Patent Publication Number: US-11649934-B2

Title: LED tube lamp

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 16/823,352 filed on Mar. 19, 2020 which is a continuation application of U.S. application Ser. No. 16/420,506 filed on May 23, 2019 which is a continuation application of U.S. application Ser. No. 16/026,331 filed on Jul. 3, 2018 which is a C.A. of U.S. application Ser. No. 15/888,335 filed on Feb. 5, 2018. 
     The U.S. application Ser. No. 15/888,335 is a C.A. of U.S. application Ser. No. 15/643,034 filed on Jul. 6, 2017 which is a continuation-in-part application of U.S. application Ser. No. 15/298,955 filed on Oct. 20, 2016 and issued at U.S. Pat. No. 9,845,923 on Dec. 19, 2017, U.S. application Ser. No. 15/055,630 filed on Feb. 28, 2016, U.S. application Ser. No. 15/339,221 filed on Oct. 31, 2016, U.S. application Ser. No. 15/258,068 filed on Sep. 7, 2016, U.S. application Ser. No. 15/211,783 filed on Jul. 15, 2016, and U.S. application Ser. No. 15/483,368 filed on Apr. 10, 2017, wherein the Ser. No. 15/298,955 application is a continuation application of U.S. application Ser. No. 14/865,387 filed in United States on Sep. 25, 2015, which itself claims Chinese priorities under 35 U.S.C. § 119(a) of Patent Applications No. CN 201410507660.9 filed on 2014 Sep. 28; CN 201410508899.8 filed on 2014 Sep. 28; CN 201410623355.6 filed on 2014 Nov. 6; CN 201410734425.5 filed on 2014 Dec. 5; CN 201510075925.7 filed on 2015 Feb. 12; CN 201510104823.3 filed on 2015 Mar. 10; CN 201510134586.5 filed on 2015 Mar. 26; CN 201510133689.x filed on 2015 Mar. 25; CN 201510136796.8 filed on 2015 Mar. 27; CN 201510173861.4 filed on 2015 Apr. 14; CN 201510155807.7 filed on 2015 Apr. 3; CN 201510193980.6 filed on 2015 Apr. 22; CN 201510372375.5 filed on 2015 Jun. 26; CN 201510259151.3 filed on 2015 May 19; CN 201510268927.8 filed on 2015 May 22; CN 201510284720.x filed on 2015 May 29; CN 201510338027.6 filed on 2015 Jun. 17; CN 201510315636.x filed on 2015 Jun. 10; CN 201510373492.3 filed on 2015 Jun. 26; CN 201510364735.7 filed on 2015 Jun. 26; CN 201510378322.4 filed on 2015 Jun. 29; CN 201510391910.1 filed on 2015 Jul. 2; CN 201510406595.5 filed on 2015 Jul. 10; CN 201510482944.1 filed on 2015 Aug. 7; CN 201510486115.0 filed on 2015 Aug. 8; CN 201510428680.1 filed on 2015 Jul. 20; CN 201510483475.5 filed on 2015 Aug. 8; CN 201510555543.4 filed on 2015 Sep. 2; CN 201510557717.0 filed on 2015 Sep. 6; CN 201510595173.7 filed on 2015 Sep. 18; CN 201510724263.1 filed on 2015 Oct. 29; and CN 201510726365.7 filed on 2015 Oct. 30, the disclosures of which are incorporated herein in their entirety by reference. This application is also a continuation application of U.S. application Ser. No. 15/211,783 filed on Jul. 15, 2016 which is a continuation-in-part application of U.S. application Ser. No. 14/865,387 filed on Sep. 25, 2015, the disclosures of which are incorporated herein in their entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to illumination devices, and more particularly to an LED tube lamp and its components including the light sources, electronic components, and end caps. 
     BACKGROUND 
     LED lighting technology is rapidly developing to replace traditional incandescent and fluorescent lightings. LED tube lamps are mercury-free in comparison with fluorescent tube lamps that need to be filled with inert gas and mercury. Thus, it is not surprising that LED tube lamps are becoming a highly desired illumination option among different available lighting systems used in homes and workplaces, which used to be dominated by traditional lighting options such as compact fluorescent light bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tube lamps include improved durability and longevity and far less energy consumption; therefore, when taking into account all factors, they would typically be considered as a cost effective lighting option. 
     Typical LED tube lamps have a lamp tube, a circuit board disposed inside the lamp tube with light sources being mounted on the circuit board, and end caps accompanying a power supply provided at two ends of the lamp tube with the electricity from the power supply transmitting to the light sources through the circuit board. However, existing LED tube lamps have certain drawbacks. For example, the electrical components and fuses in the LED tube lamps may not perform properly due to increasing temperature inside the LED tube lamps during the use of the LED tube lamps. Specifically, the fuses very likely incorrectly cause open circuit in response to high environmental temperatures inside the LED tube lamps instead of high electrical current flow. The electrical components operate in unexpected ways which are different from circuit design. 
     Grainy visual appearances are also often found in the aforementioned conventional LED tube lamp. The LED chips spatially arranged on the circuit board inside the lamp tube are considered as spot light sources, and the lights emitted from these LED chips generally do not contribute uniform illuminance for the LED tube lamp without proper optical manipulation. As a result, the entire tube lamp would exhibit a grainy or non-uniform illumination effect to a viewer of the LED tube lamp, thereby negatively affecting the visual comfort and even narrowing the viewing angles of the lights. As a result, the quality and aesthetics requirements of average consumers would not be satisfied. To address this issue, the Chinese patent application with application no. CN 201320748271.6 discloses a diffusion tube is disposed inside a glass lamp tube to avoid grainy visual effects. 
     The Chinese patent application no. 201320156110.8 filed on Mar. 29, 2013 discloses a flexible lamp board type LED lamp tube. The flexible lamp board type LED lamp tube includes a lamp cover, a flexible LED lamp board fixed on the inner wall of the lamp cover, and lamp caps respectively installed at both ends of the lamp cover, and the lamp cap. The flexible LED lamp board is electrically connected to the flexible LED lamp board. The flexible LED lamp board includes a flexible substrate with a connecting line and LED lamp beads mounted on the flexible substrate. The flexible substrate is attached to the inner wall of the lamp cover. 
     The Chinese patent application no. 201320759840.7 filed on Nov. 26, 2013 discloses an LED lamp tube adopting flexible lamp board. The LED lamp tube comprises a lamp tube body comprising an elongated lamp body, an LED light source assembly arranged on the lamp body, a lamp cover and lamp head assembly at two ends of the lamp body. The LED light source assembly is a flexible LED strip attached to the end surface of the lamp body. 
     U.S. Pat. No. 8,791,650 filed on Dec. 10, 2011 discloses an LED lighting system. The LED lighting system is provided for connection to a variable power source providing input power, the LED lighting system having at least one power analyzing and processing circuitry connecting to the variable power source, and being configured to identify one or more characteristics of the input power, where the characteristics are selected from amplitude, frequency and pulse width of the input power, compare one or more of the characteristics of the input power to preset control criteria either in hardware or software or both to yield a comparison result, and then control the current control circuitry according to the comparison result. 
     US patent publication no. 2014/0084800A1 is a driving light emitting diode (LED) lamps using power received from ballast stabilizers. A circuit drives an LED lamp based on alternating current (AC) power received from a ballast stabilizer. The circuit includes an inductive load, a rectifying circuit, and an output circuit. The inductive load is coupled to and receives the AC power from the ballast stabilizer. The rectifying circuit is electrically coupled to the inductive load and rectifies the AC power to produce a unidirectional current. The output circuit receives the unidirectional current from the rectifying circuit, and produces an output current for driving the LED lamp. Various additional circuits and illuminating apparatuses for producing light from AC power using a LED lamp are also provided. 
     Accordingly, the present disclosure and its embodiments are herein provided. 
     SUMMARY OF THE INVENTION 
     It&#39;s especially noted that the present disclosure may actually include one or more inventions claimed currently or not yet claimed, and for avoiding confusion due to unnecessarily distinguishing between those possible inventions at the stage of preparing the specification, the possible plurality of inventions herein may be collectively referred to as “the (present) invention” herein. 
     Various embodiments are summarized in this section and are described with respect to the “present invention,” which terminology is used to describe certain presently disclosed embodiments, whether claimed or not, and is not necessarily an exhaustive description of all possible embodiments, but rather is merely a summary of certain embodiments. Certain of the embodiments described below as various aspects of the “present invention” can be combined in different manners to form an LED tube lamp or a portion thereof. 
     The present invention provides a novel LED tube lamp, and aspects thereof. 
     According to some embodiments, an LED tube lamp comprises a lamp tube, a diffusive layer covered on a surface of the lamp tube, two end caps, a light strip, LED light sources on the light strip, and a power supply. Each of the two end caps is coupled to a respective end of the lamp tube. The light strip is attached to an inner circumferential surface of the lamp tube. The power supply module comprises a printed circuit board electrically connected to the light strip, a rectifying circuit and a filtering circuit coupled to the rectifying circuit. An end of the light strip is detached from the inner circumferential surface of the lamp tube and electrically connected to the printed circuit board. 
     According to some embodiments, the end of the light strip is detached from the inner circumferential surface of the lamp tube within the lamp tube. 
     According to some embodiments, the light strip is soldered to the printed circuit board. 
     According to some embodiments, the end of the light strip is detached from the inner circumferential surface of the lamp tube to form a freely ending portion with the freely ending portion being curled up, coiled or deformed in shape to be fittingly accommodated within the LED tube lamp. 
     According to some embodiments, the freely ending portion forms a shape of “Z” or “S” inside the LED tube lamp. 
     According to some embodiments, the LED tube lamp further comprises a protective layer disposed on the light strip. 
     According to some embodiments, the end of the light strip and the printed circuit board are stacked on each other. 
     According to some embodiments, the light strip comprises two soldering pads arranged at the freely ending portion, and each of the two soldering pads is formed with a through-hole. 
     According to some embodiments, the light strip comprises two soldering pads arranged at the freely ending portion, and each of the two soldering pads is formed with a notch. 
     According to some embodiments, the first filtering unit comprises a first capacitor. The first capacitor has an end electrically connected to the first rectifying output terminal and the other end electrically connected to the second rectifying output terminal. 
     According to some embodiments, the filtering circuit comprises an EMI-reducing capacitor coupled between input terminals of the rectifying circuit. 
     According to some embodiments, the filtering circuit comprises a first resistor and a second capacitor. The first resistor has an end coupled to a pin on one of the end caps. The second capacitor has an end coupled to the other end of the first resistor, and the other end coupled to one of input terminals of the rectifying circuit. 
     According to some embodiments, the filtering circuit comprises a passive component coupled to the second capacitor in parallel. 
     According to some embodiments, the passive component is an inductor. 
     According to some embodiments, the rectifying circuit comprises a first diode, a second diode, a third diode and a fourth diode. The first diode has an anode connected to the second output terminal, and a cathode connected to a pin on one of the end caps. The second diode has an anode connected to the second output terminal, and a cathode connected to a pin on the other one of the end caps. The third diode has an anode connected to the pin on the one of the end caps, and a cathode connected to the first output terminal. The fourth diode has an anode connected to the pin on the other one of the end caps, and a cathode connected to the first output terminal. 
     According to some embodiments, the rectifying circuit further comprises a terminal adapter circuit coupled to the cathode of the first diode, the anode of the second diode, and the pins on both of the end caps. The terminal adapter circuit is configured to transmit signal received from at least one of the pins to the cathode of the first diode and the anode of the second diode. 
     According to some embodiments, the terminal adapter circuit comprises a third capacitor and a fourth capacitor. The third capacitor has an end connected to the pin on the other one of the end caps, and the other end connected to the cathode of the first diode and the anode of the second diode. The fourth capacitor has an end connected to the pin on the one of the end caps, and the other end connected to the other end of the third capacitor. 
     According to some embodiments, the terminal adapter circuit comprises a first fuse and a second fuse. The first fuse has an end connected to the pin on the other one of the end caps, and the other end connected to the cathode of the first diode and the anode of the second diode. The second fuse has an end connected to the pin on the one of the end caps, and the other end connected to the other end of the first fuse. 
     According to some embodiments, the printed circuit board comprises two first soldering pads arranged on a top surface thereof. The plurality of LED light sources is mounted on a top surface of the light strip. The end of the light strip is detached from the inner circumferential surface of the lamp tube to form a freely ending portion soldered to the two first soldering pads on the top surface of the printed circuit board. 
     According to some embodiments, the light strip comprises two second soldering pads arranged at the freely ending portion. Each of the two second soldering pads is formed with a through-hole and is soldered to a corresponding one of the two first soldering pads. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view schematically illustrating an LED tube lamp according to one embodiment of the present invention; 
         FIG.  1 A  is a perspective view schematically illustrating the different length end caps of an LED tube lamp according to another embodiment of the present invention to illustrate; 
         FIG.  1 B  is an exemplary exploded view schematically illustrating the LED tube lamp shown in  FIG.  1   ; 
         FIG.  2    illustrates an exploded view of an LED tube lamp including a heat shrink sleeve according to an embodiment of the present invention; 
         FIG.  3    is a perspective view schematically illustrating front and top of an end cap of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  4    is an exemplary perspective view schematically illustrating bottom of the end cap as shown in  FIG.  3   ; 
         FIG.  5    is a plane cross-sectional partial view schematically illustrating a connecting region of the end cap and the lamp tube of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  6    is a perspective cross-sectional view schematically illustrating inner structure of an all-plastic end cap (having a magnetic metal member and hot melt adhesive inside) according to another embodiment of the present invention; 
         FIG.  7    is a perspective view schematically illustrating the all-plastic end cap and the lamp tube being bonded together by utilizing an induction coil according to certain embodiments of the present invention; 
         FIG.  8    is a perspective view schematically illustrating a supporting portion and a protruding portion of the electrically insulating tube of the end cap of the LED tube lamp according to another embodiment of the present invention; 
         FIG.  9    is an exemplary plane cross-sectional view schematically illustrating the inner structure of the electrically insulating tube and the magnetic metal member of the end cap of  FIG.  8    taken along a line X-X; 
         FIG.  10    is a plane view schematically illustrating the configuration of the openings on surface of the magnetic metal member of the end cap of the LED tube lamp according to another embodiment of the present invention; 
         FIG.  11    is a plane view schematically illustrating the indentation/embossment on a surface of the magnetic metal member of the end cap of the LED tube lamp according to certain embodiments of the present invention; 
         FIG.  12    is an exemplary plane cross-sectional view schematically illustrating the structure of the connection of the end cap of  FIG.  8    and the lamp tube along a radial axis of the lamp tube, where the electrically insulating tube is in shape of a circular ring; 
         FIG.  13    is an exemplary plane cross-sectional view schematically illustrating the structure of the connection of the end cap of  FIG.  8    and the lamp tube along a radial axis of the lamp tube, where the electrically insulating tube is in shape of an elliptical or oval ring; 
         FIG.  14    is a perspective view schematically illustrating still another end cap of an LED tube lamp according to still another embodiment of the prevent invention; 
         FIG.  15    is a plane cross-sectional view schematically illustrating end structure of a lamp tube of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  16    is an exemplary plane cross-sectional view schematically illustrating the local structure of the transition region of the end of the lamp tube of  FIG.  15   ; 
         FIG.  17    is a plane cross-sectional view schematically illustrating inside structure of the lamp tube of the LED tube lamp according to one embodiment of the present invention, wherein two reflective films are respectively adjacent to two sides of the LED light strip along the circumferential direction of the lamp tube; 
         FIG.  18    is a plane cross-sectional view schematically illustrating inside structure of the lamp tube of the LED tube lamp according to another embodiment of the present invention, wherein only a reflective film is disposed on one side of the LED light strip along the circumferential direction of the lamp tube; 
         FIG.  19    is a plane cross-sectional view schematically illustrating inside structure of the lamp tube of the LED tube lamp according to still another embodiment of the present invention, wherein the reflective film is under the LED light strip and extends at both sides along the circumferential direction of the lamp tube; 
         FIG.  20    is a plane cross-sectional view schematically illustrating inside structure of the lamp tube of the LED tube lamp according to yet another embodiment of the present invention, wherein the reflective film is under the LED light strip and extends at only one side along the circumferential direction of the lamp tube; 
         FIG.  21    is a plane cross-sectional view schematically illustrating inside structure of the lamp tube of the LED tube lamp according to still yet another embodiment of the present invention, wherein two reflective films are respectively adjacent to two sides of the LED light strip and extending along the circumferential direction of the lamp tube; 
         FIG.  22    is a plane sectional view schematically illustrating the LED light strip is a bendable circuit sheet with ends thereof passing across the transition region of the lamp tube of the LED tube lamp to be soldering bonded to the output terminals of the power supply according to one embodiment of the present invention; 
         FIG.  23    is a plane cross-sectional view schematically illustrating a bi-layered structure of the bendable circuit sheet of the LED light strip of the LED tube lamp according to an embodiment of the present invention; 
         FIG.  24    is a perspective view schematically illustrating the soldering pad of the bendable circuit sheet of the LED light strip for soldering connection with the printed circuit board of the power supply of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  25    is a plane view schematically illustrating the arrangement of the soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  26    is a plane view schematically illustrating a row of three soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to another embodiment of the present invention; 
         FIG.  27    is a plane view schematically illustrating two rows of soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to still another embodiment of the present invention; 
         FIG.  28    is a plane view schematically illustrating a row of four soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to yet another embodiment of the present invention; 
         FIG.  29    is a plane view schematically illustrating two rows of two soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to yet still another embodiment of the present invention; 
         FIG.  30    is a plane view schematically illustrating through holes are formed on the soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  31    is a plane cross-sectional view schematically illustrating soldering bonding process utilizing the soldering pads of the bendable circuit sheet of the LED light strip of  FIG.  30    taken from side view and the printed circuit board of the power supply according to one embodiment of the present invention; 
         FIG.  32    is a plane cross-sectional view schematically illustrating soldering bonding process utilizing the soldering pads of the bendable circuit sheet of the LED light strip of  FIG.  30    taken from side view and the printed circuit board of the power supply according to another embodiment of the present invention, wherein the through hole of the soldering pads is near the edge of the bendable circuit sheet; 
         FIG.  33    is a plane view schematically illustrating notches formed on the soldering pads of the bendable circuit sheet of the LED light strip of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  34    is an exemplary plane cross-sectional view of  FIG.  33    taken along a line A-A′; 
         FIG.  35    is a perspective view schematically illustrating a circuit board assembly composed of the bendable circuit sheet of the LED light strip and the printed circuit board of the power supply according to another embodiment of the present invention; 
         FIG.  36    is a perspective view schematically illustrating another arrangement of the circuit board assembly of  FIG.  35   ; 
         FIG.  37    is a perspective view schematically illustrating an LED lead frame for the LED light sources of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  38    is a perspective view schematically illustrating a power supply of the LED tube lamp according to one embodiment of the present invention; 
         FIG.  39    is a perspective view schematically illustrating the printed circuit board of the power supply, which is perpendicularly adhered to a hard circuit board made of aluminum via soldering according to another embodiment of the present invention; 
         FIG.  40    is a perspective view illustrating a thermos-compression head used in soldering the bendable circuit sheet of the LED light strip and the printed circuit board of the power supply according to one embodiment of the present invention; 
         FIG.  41    is a plane view schematically illustrating the thickness difference between two solders on the pads of the bendable circuit sheet of the LED light strip or the printed circuit board of the power supply according to one embodiment of the invention; 
         FIG.  42    is a perspective view schematically illustrating the soldering vehicle for soldering the bendable circuit sheet of the LED light strip and the printed circuit board of the power supply according to one embodiment of the invention; 
         FIG.  43    is an exemplary plan view schematically illustrating a rotation status of the rotary platform of the soldering vehicle in  FIG.  41   ; 
         FIG.  44    is a plan view schematically illustrating an external equipment for heating the hot melt adhesive according to another embodiment of the present invention; 
         FIG.  45    is a cross-sectional view schematically illustrating the hot melt adhesive having uniformly distributed high permeability powder particles with small particle size according to one embodiment of the present invention; 
         FIG.  46    is a cross-sectional view schematically illustrating the hot melt adhesive having non-uniformly distributed high permeability powder particles with small particle size according to another embodiment of the present invention, wherein the powder particles form a closed electric loop; 
         FIG.  47    is a cross-sectional view schematically illustrating the hot melt adhesive having non-uniformly distributed high permeability powder particles with large particle size according to yet another embodiment of the present invention, wherein the powder particles form a closed electric loop; 
         FIG.  48    is a perspective view schematically illustrating the bendable circuit sheet of the LED light strip is formed with two conductive wiring layers according to another embodiment of the present invention; 
         FIG.  49 A  is a block diagram of an exemplary power supply module  250  in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  49 B  is a block diagram of an exemplary power supply module  250  in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  49 C  is a block diagram of an exemplary LED lamp according to some embodiments of the present invention; 
         FIG.  49 D  is a block diagram of an exemplary power supply module  250  in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  49 E  is a block diagram of an LED lamp according to some embodiments of the present invention; 
         FIG.  50 A  is a schematic diagram of a rectifying circuit according to some embodiments of the present invention; 
         FIG.  50 B  is a schematic diagram of a rectifying circuit according to some embodiments of the present invention; 
         FIG.  50 C  is a schematic diagram of a rectifying circuit according to some embodiments of the present invention; 
         FIG.  50 D  is a schematic diagram of a rectifying circuit according to some embodiments of the present invention; 
         FIG.  51 A  is a schematic diagram of a terminal adapter circuit according to some embodiments of the present invention; 
         FIG.  51 B  is a schematic diagram of a terminal adapter circuit according to some embodiments of the present invention; 
         FIG.  51 C  is a schematic diagram of a terminal adapter circuit according to some embodiments of the present invention; 
         FIG.  51 D  is a schematic diagram of a terminal adapter circuit according to some embodiments of the present invention; 
         FIG.  52 A  is a block diagram of a filtering circuit according to some embodiments of the present invention; 
         FIG.  52 B  is a schematic diagram of a filtering unit according to some embodiments of the present invention; 
         FIG.  52 C  is a schematic diagram of a filtering unit according to some embodiments of the present invention; 
         FIG.  52 D  is a schematic diagram of a filtering unit according to some embodiments of the present invention; 
         FIG.  52 E  is a schematic diagram of a filtering unit according to some embodiments of the present invention; 
         FIG.  53 A  is a schematic diagram of an LED module according to some embodiments of the present invention; 
         FIG.  53 B  is a schematic diagram of an LED module according to some embodiments of the present invention; 
         FIG.  53 C  is a plan view of a circuit layout of the LED module according to some embodiments of the present invention; 
         FIG.  53 D  is a plan view of a circuit layout of the LED module according to some embodiments of the present invention; 
         FIG.  53 E  is a plan view of a circuit layout of the LED module according to some embodiments of the present invention; 
         FIG.  54 A  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  54 B  is a block diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 C  is a schematic diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 D  is a schematic diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 E  is a schematic diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 F  is a schematic diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 G  is a block diagram of a driving circuit according to some embodiments of the present invention; 
         FIG.  54 H  is a graph illustrating the relationship between the voltage Vin and the objective current Iout according to certain embodiments of the present invention; 
         FIG.  55 A  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  55 B  is a schematic diagram of an anti-flickering circuit according to some embodiments of the present invention; 
         FIG.  56 A  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  56 B  is a schematic diagram of a protection circuit according to some embodiments of the present invention; 
         FIG.  57 A  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 B  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 C  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 D  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 E  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 F  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 G  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 H  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  57 I  is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiment of the present invention; 
         FIG.  58 A  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 B  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 C  illustrates an arrangement with a ballast-compatible circuit in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 D  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 E  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 F  is a schematic diagram of a ballast-compatible circuit according to some embodiments of the present invention; 
         FIG.  58 G  is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments of the present invention; 
         FIG.  58 H  is a schematic diagram of a ballast-compatible circuit according to some embodiments of the present invention; 
         FIG.  58 I  illustrates a ballast-compatible circuit according to some embodiments of the present invention; 
         FIG.  59 A  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  59 B  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  59 C  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  59 D  is a schematic diagram of a ballast-compatible circuit according to some embodiments of the present invention, which is applicable to the embodiments shown in  FIGS.  59 A and  59 B  and the described modification thereof; 
         FIG.  60 A  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  60 B  is a schematic diagram of a filament-simulating circuit according to some embodiments of the present invention; 
         FIG.  60 C  is a schematic block diagram including a filament-simulating circuit according to some embodiments of the present invention; 
         FIG.  60 D  is a schematic block diagram including a filament-simulating circuit according to some embodiments of the present invention; 
         FIG.  60 E  is a schematic diagram of a filament-simulating circuit according to some embodiments of the present invention; 
         FIG.  60 F  is a schematic block diagram including a filament-simulating circuit according to some embodiments of the present invention; 
         FIG.  61 A  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  61 B  is a schematic diagram of an OVP circuit according to an embodiment of the present invention; 
         FIG.  62 A  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  62 B  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  62 C  is a block diagram of a ballast detection circuit according to some embodiments of the present invention; 
         FIG.  62 D  is a schematic diagram of a ballast detection circuit according to some embodiments of the present invention; 
         FIG.  62 E  is a schematic diagram of a ballast detection circuit according to some embodiments of the present invention; 
         FIG.  63 A  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  63 B  is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  63 C  is a schematic diagram of an auxiliary power module according to an embodiment of the present invention; 
         FIG.  64    is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments of the present invention; 
         FIG.  65    illustrates a block diagram of an exemplary power supply module in an LED tube lamp according to one embodiment of the present invention; 
         FIG.  66    illustrates a perspective view of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  67    illustrates an exploded view of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  68    illustrates a partial view of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  69    illustrates a part of a cross section of  FIG.  3    along the line A-A′; 
         FIG.  70    illustrates a part of a cross section of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  71    illustrates a part of a cross section of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIGS.  72  to  79    illustrate partial views of LED tube lamps according to several embodiments of the instant disclosure; 
         FIGS.  80  to  83    illustrate a part of cross sections of LED tube lamps according to several embodiments of the instant disclosure; 
         FIGS.  84  and  85    illustrate a part of cross sections of LED tube lamps installed to lamp bases according to several embodiments of the instant disclosure; 
         FIG.  86    illustrates a perspective view of an LED tube lamp installed to a lamp base according to an embodiment of the instant disclosure; 
         FIG.  87    illustrates a partial view of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  88    illustrates a part of a cross section of  FIG.  87    along the line B-B′; 
         FIG.  89    illustrates a partially steric cross section of  FIG.  87   ; 
         FIG.  90    illustrates a partially steric cross section of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  91    illustrates a part of a cross section of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  92    illustrates an end view of an LED tube lamp in which the viewing angle is substantially parallel with an axle of an end cap according to an embodiment of the instant disclosure; 
         FIG.  93    illustrates a radial cross section of an end cap of  FIG.  92   ; 
         FIG.  94    illustrates a part of an axial cross section of  FIG.  92    along the line C-C′; 
         FIGS.  95  and  96    illustrate a part of axial cross sections of LED tube lamps according to several embodiments of the instant disclosure; 
         FIG.  97    illustrates a partial view of an LED tube lamp according to an embodiment of the instant disclosure, and some components thereof are transparent; 
         FIG.  98    illustrates a partial view of an LED tube lamp according to an embodiment of the instant disclosure; 
         FIG.  99    illustrates a part of a cross section of  FIG.  98    along the line D-D′, and a light sensor is added; 
         FIG.  100    illustrates a partial view of a LED light strip and a power supply soldered to each other according to an embodiment of the instant disclosure; and 
         FIGS.  101  to  103    illustrate diagrams of a soldering process of the LED light strip and the power supply according to an embodiment of the instant disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides a novel LED tube lamp. The present disclosure will now be described in the following embodiments with reference to the drawings. The following descriptions of various embodiments of this invention are presented herein for purpose of illustration and giving examples only. It is not intended to be exhaustive or to be limited to the precise form disclosed. These example embodiments are just that—examples—and many implementations and variations are possible that do not require the details provided herein. It should also be emphasized that the disclosure provides details of alternative examples, but such listing of alternatives is not exhaustive. Furthermore, any consistency of detail between various examples should not be interpreted as requiring such detail—it is impracticable to list every possible variation for every feature described herein. The language of the claims should be referenced in determining the requirements of the invention. 
     In the drawings, the size and relative sizes of components may be exaggerated for clarity. Like numbers refer to like elements throughout. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”. 
     It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, or steps, these elements, components, regions, layers, and/or steps should not be limited by these terms. Unless the context indicates otherwise, these terms are only used to distinguish one element, component, region, layer, or step from another element, component, region, or step, for example as a naming convention. Thus, a first element, component, region, layer, or step discussed below in one section of the specification could be termed a second element, component, region, layer, or step in another section of the specification or in the claims without departing from the teachings of the present invention. In addition, in certain cases, even if a term is not described using “first,” “second,” etc., in the specification, it may still be referred to as “first” or “second” in a claim in order to distinguish different claimed elements from each other. 
     It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to or “on” another element, it can be directly connected or coupled to or on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). However, the term “contact,” as used herein refers to direct contact (i.e., touching) unless the context indicates otherwise. 
     Embodiments described herein will be described referring to plan views and/or cross-sectional views by way of ideal schematic views. Accordingly, the exemplary views may be modified depending on manufacturing technologies and/or tolerances. Therefore, the disclosed embodiments are not limited to those shown in the views, but include modifications in configuration formed on the basis of manufacturing processes. Therefore, regions exemplified in figures may have schematic properties, and shapes of regions shown in figures may exemplify specific shapes of regions of elements to which aspects of the invention are not limited. 
     Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     Terms such as “same,” “equal,” “planar,” or “coplanar,” as used herein when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to reflect this meaning. 
     Terms such as “about” or “approximately” may reflect sizes, orientations, or layouts that vary only in a small relative manner, and/or in a way that does not significantly alter the operation, functionality, or structure of certain elements. For example, a range from “about 0.1 to about 1” may encompass a range such as a 0%-5% deviation around 0.1 and a 0% to 5% deviation around 1, especially if such deviation maintains the same effect as the listed range. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     As used herein, items described as being “electrically connected” are configured such that an electrical signal can be passed from one item to the other. Therefore, a passive electrically conductive component (e.g., a wire, pad, internal electrical line, etc.) physically connected to a passive electrically insulative component (e.g., a prepreg layer of a printed circuit board, an electrically insulative adhesive connecting two devices, an electrically insulative underfill or mold layer, etc.) is not electrically connected to that component. Moreover, items that are “directly electrically connected,” to each other are electrically connected through one or more passive elements, such as, for example, wires, pads, internal electrical lines, resistors, etc. As such, directly electrically connected components do not include components electrically connected through active elements, such as transistors or diodes. 
     Components described as thermally connected or in thermal communication are arranged such that heat will follow a path between the components to allow the heat to transfer from the first component to the second component. Simply because two components are part of the same device or board does not make them thermally connected. In general, components which are heat-conductive and directly connected to other heat-conductive or heat-generating components (or connected to those components through intermediate heat-conductive components or in such close proximity as to permit a substantial transfer of heat) will be described as thermally connected to those components, or in thermal communication with those components. On the contrary, two components with heat-insulative materials therebetween, which materials significantly prevent heat transfer between the two components, or only allow for incidental heat transfer, are not described as thermally connected or in thermal communication with each other. The terms “heat-conductive” or “thermally-conductive” do not apply to any material that provides incidental heat conduction, but are intended to refer to materials that are typically known as good heat conductors or known to have utility for transferring heat, or components having similar heat conducting properties as those materials. 
     Referring to  FIGS.  1 ,  1 A,  1 B and  2   , an LED tube lamp of one embodiment of the present invention includes a lamp tube  1 , an LED light strip  2  disposed inside the lamp tube  1 , and two end caps  3  respectively disposed at two ends of the lamp tube  1 . The lamp tube  1  may be made of plastic or glass. The lengths of the two end caps  3  may be same or different. Referring to  FIG.  1 A , the length of one end cap may in some embodiments be about 30% to about 80% times the length of the other end cap. 
     In one embodiment, the lamp tube  1  is made of glass with strengthened or tempered structure to avoid being easily broken and incurring electrical shock occurred to conventional glass made tube lamps, and to avoid the fast aging process that often occurs in plastic made tube lamps. The glass made lamp tube  1  may be additionally strengthened or tempered by a chemical tempering method or a physical tempering method in various embodiments of the present invention. 
     An exemplary chemical tempering method is accomplished by exchanging the Na ions or K ions on the glass surface with other alkali metal ions and therefore changes composition of the glass surface. The sodium (Na) ions or potassium (K) ions and other alkali metal ions on the glass surface are exchanged to form an ion exchange layer on the glass surface. The glass is then under tension on the inside while under compression on the outside when cooled to room temperature, so as to achieve the purpose of increased strength. The chemical tempering method includes but is not limited to the following glass tempering methods: high temperature type ion exchange method, the low temperature type ion exchange method, dealkalization, surface crystallization, and/or sodium silicate strengthening methods, further explained as follows. 
     An exemplary embodiment of the high temperature type ion exchange method includes the following steps: Inserting glass containing sodium oxide (Na 2 O) or potassium oxide (K 2 O) in the temperature range of the softening point and glass transition point into molten salt of lithium, so that the Na ions in the glass are exchanged for Li ions in the molten salt. Later, the glass is then cooled to room temperature, since the surface layer containing Li ions has a different expansion coefficient with respect to the inner layer containing Na ions or K ions, thus the surface produces residual stress and is reinforced. Meanwhile, the glass containing Al 2 O 3 , TiO 2  and other components, by performing ion exchange, can produce glass crystals having an extremely low coefficient of expansion. The crystallized glass surface after cooling produces a significant amount of pressure, up to 700 MPa, which can enhance the strength of glass. 
     An exemplary embodiment of the low-temperature ion exchange method includes the following steps: First, a monovalent cation (e.g., K ions) undergoes ion exchange with the alkali ions (e.g. Na ion) on the surface layer at a temperature range that is lower than the strain point temperature, so as to allow the K ions to penetrate the surface. For example, for manufacturing a Na 2 O+CaO+SiO 2  system glass, the glass can be impregnated for ten hours at more than four hundred degrees in the molten salt. The low temperature ion exchange method can easily obtain glass of higher strength, and the processing method is simple, does not damage the transparent nature of the glass surface, and does not undergo shape distortion. 
     An exemplary embodiment of dealkalization includes treating glass using platinum (Pt) catalyst along with sulfurous acid gas and water in a high temperature atmosphere. The Na +  ions are migrated out and bleed from the glass surface to be reacted with the Pt catalyst, so that the surface layer becomes a SiO 2  enriched layer, which results in a low expansion glass and produces compressive stress upon cooling. 
     The surface crystallization method and the high temperature type ion exchange method are different, but only the surface layer is treated by heat treatment to form low expansion coefficient microcrystals on the glass surface, thus reinforcing the glass. 
     An exemplary embodiment of the sodium silicate glass strengthening method is a tempering method using sodium silicate (water glass) in water solution at 100 degrees Celsius and several atmospheres of pressure treatment, where a stronger/higher strength glass surface that is harder to scratch is thereby produced. 
     An exemplary embodiment of the physical tempering method includes but is not limited to applying a coating to or changing the structure of an object such as to strengthen the easily broken position. The applied coating can be, for example, a ceramic coating, an acrylic coating, or a glass coating depending on the material used. The coating can be performed in a liquid phase or gaseous phase. 
     The above glass tempering methods described including physical tempering methods and chemical tempering methods can be accomplished singly or combined together in any fashion. 
     Referring to  FIG.  1 B  and  FIG.  15   , a glass made lamp tube of an LED tube lamp according to one embodiment of the present invention has structure-strengthened end regions described as follows. The glass made lamp tube  1  includes a main body region  102 , two rear end regions  101  (or just end regions  101 ) respectively formed at two ends of the main body region  102 , and end caps  3  that respectively sleeve the rear end regions  101 . The outer diameter of at least one of the rear end regions  101  is less than the outer diameter of the main body region  102 . In the embodiment of  FIGS.  1 B and  15   , the outer diameters of the two rear end regions  101  are less than the outer diameter of the main body region  102 . In addition, the surface of the rear end region  101  is in parallel with the surface of the main body region  102  in a cross-sectional view. Specifically, the glass made lamp tube  1  is strengthened at both ends, such that the rear end regions  101  are formed to be strengthened structures. In certain embodiments, the rear end regions  101  with strengthened structure are respectively sleeved with the end caps  3 , and the outer diameters of the end caps  3  and the main body region  102  have little or no differences. For example, the end caps  3  may have the same or substantially the same outer diameters as that of the main body region  102  such that there is no gap between the end caps  3  and the main body region  102 . In this way, a supporting seat in a packing box for transportation of the LED tube lamp contacts not only the end caps  3  but also the lamp tube  1  and makes uniform the loadings on the entire LED tube lamp to avoid situations where only the end caps  3  are forced, therefore preventing breakage at the connecting portion between the end caps  3  and the rear end regions  101  due to stress concentration. The quality and the appearance of the product are therefore improved. 
     In one embodiment, the end caps  3  and the main body region  102  have substantially the same outer diameters. These diameters may have a tolerance for example within +/−0.2 millimeter (mm), or in some cases up to +/−1.0 millimeter (mm). Depending on the thickness of the end caps  3 , the difference between an outer diameter of the rear end regions  101  and an outer diameter of the main body region  102  can be about 1 mm to about 10 mm for typical product applications. In some embodiments, the difference between the outer diameter of the rear end regions  101  and the outer diameter of the main body region  102  can be about 2 mm to about 7 mm. 
     Referring to  FIG.  2   , the LED tube lamp  1  may have a heat shrink sleeve  190  covering on the outer surface of the lamp tube  1 . In some embodiments, the heat shrink sleeve  190  may have a thickness ranging between 20 μm and 200 μm and is substantially transparent with respect to the wavelength of light from the LED light sources  202 . In some embodiments, the heat shrink sleeve  190  may be made of PFA (perfluoroalkoxy) or PTFE (polytetrafluoroethylene). The heat shrink sleeve  190  may be slightly larger than the lamp tube  1  and may be shrunk and tightly cover the outer surface of the lamp tube  1  while being heated to an appropriate temperature (ex, 260° C. for PFA and PTFE). 
     Referring to  FIG.  15   , the lamp tube  1  is further formed with a transition region  103  between the main body region  102  and the rear end regions  101 . In one embodiment, the transition region  103  is a curved region formed to have cambers at two ends to smoothly connect the main body region  102  and the rear end regions  101 , respectively. For example, the two ends of the transition region  103  may be arc-shaped in a cross-section view along the axial direction of the lamp tube  1 . Furthermore, one of the cambers connects the main body region  102  while the other one of the cambers connects the rear end region  101 . In some embodiments, the arc angle of the cambers is greater than 90 degrees while the outer surface of the rear end region  101  is a continuous surface in parallel with the outer surface of the main body region  102  when viewed from the cross-section along the axial direction of the lamp tube. In other embodiments, the transition region  103  can be without curve or arc in shape. In certain embodiments, the length of the transition region  103  along the axial direction of the lamp tube  1  is between about 1 mm to about 4 mm. Upon experimentation, it was found that when the length of the transition region  103  along the axial direction of the lamp tube  1  is less than 1 mm, the strength of the transition region would be insufficient; when the length of the transition region  103  along the axial direction of the lamp tube  1  is more than 4 mm, the main body region  102  would be shorter and the desired illumination surface would be reduced, and the end caps  3  would be longer and the more materials for the end caps  3  would be needed. 
     Referring to  FIG.  5    and  FIG.  16   , in certain embodiments, the lamp tube  1  is made of glass, and has a rear end region  101 , a main body region  102 , and a transition region  103 . The transition region  103  has two arc-shaped cambers at both ends to form an S shape; one camber positioned near the main body region  102  is convex outwardly, while the other camber positioned near the rear end region  101  is concaved inwardly. Generally speaking, the radius of curvature, R1, of the camber/arc between the transition region  103  and the main body region  102  is smaller than the radius of curvature, R2, of the camber/arc between the transition region  103  and the rear end region  101 . The ratio R1:R2 may range, for example, from about 1:1.5 to about 1:10, and in some embodiments is more effective from about 1:2.5 to about 1:5, and in some embodiments is even more effective from about 1:3 to about 1:4. In this way, the camber/arc of the transition region  103  positioned near the rear end region  101  is in compression at outer surfaces and in tension at inner surfaces, and the camber/arc of the transition region  103  positioned near the main body region  102  is in tension at outer surfaces and in compression at inner surfaces. Therefore, the goal of strengthening the transition region  103  of the lamp tube  1  is achieved. 
     Taking the standard specification for T8 lamp as an example, the outer diameter of the rear end region  101  is configured between 20.9 mm to 23 mm. An outer diameter of the rear end region  101  is less than 20.9 mm would be too small to fittingly insert the power supply into the lamp tube  1 . The outer diameter of the main body region  102  is in some embodiments configured to be between about 25 mm to about 28 mm. An outer diameter of the main body region  102  being less than 25 mm would be inconvenient to strengthen the ends of the main body region  102  as far as the current manufacturing skills are concerned, while an outer diameter of the main body region  102  being greater than 28 mm is not compliant to the industrial standard. 
     Referring to  FIGS.  3  and  4   , in one embodiment of the invention, each end cap  3  includes an electrically insulating tube  302 , a thermal conductive member  303  sleeving over the electrically insulating tube  302 , and two hollow conductive pins  301  disposed on the electrically insulating tube  302 . The thermal conductive member  303  can be a metal ring that is tubular in shape. 
     Referring  FIG.  5   , in one embodiment, one end of the thermal conductive member  303  extends away from the electrically insulating tube  302  of the end cap  3  and towards one end of the lamp tube  1  and is bonded and adhered to the end of the lamp tube  1  using a hot melt adhesive  6 . In this way, the end cap  3  by way of the thermal conductive member  303  extends to the transition region  103  of the lamp tube  1 . In one embodiment, the thermal conductive member  303  and the transition region  103  are closely connected such that the hot melt adhesive  6  would not overflow out of the end cap  3  and remain on the main body region  102  when using the hot melt adhesive  6  to join the thermal conductive member  303  and the lamp tube  1 . In addition, the electrically insulating tube  302  facing toward the lamp tube  1  does not have an end extending to the transition region  103 , and that there is a gap between the electrically insulating tube  302  and the transition region  103 . In one embodiment, the electrically insulating tube  302  is not limited to being made of plastic or ceramic, any material that is not a good electrical conductor can be used. 
     The hot melt adhesive  6  is a composite including a so-called commonly known as “welding mud powder”, and in some embodiments includes one or more of phenolic resin 2127#, shellac, rosin, calcium carbonate powder, zinc oxide, and ethanol. Rosin is a thickening agent with a feature of being dissolved in ethanol but not dissolved in water. In one embodiment, a hot melt adhesive  6  having rosin could be expanded to change its physical status to become solidified when being heated to high temperature in addition to the intrinsic viscosity. Therefore, the end cap  3  and the lamp tube  1  can be adhered closely by using the hot melt adhesive to accomplish automatic manufacture for the LED tube lamps. In one embodiment, the hot melt adhesive  6  may be expansive and flowing and finally solidified after cooling. In this embodiment, the volume of the hot melt adhesive  6  expands to about 1.3 times the original size when heated from room temperature to about 200 to 250 degrees Celsius. The hot melt adhesive  6  is not limited to the materials recited herein. Alternatively, a material for the hot melt adhesive  6  to be solidified immediately when heated to a predetermined temperature can be used. The hot melt adhesive  6  provided in each embodiments of the present invention is durable with respect to high temperature inside the end caps  3  due to the heat resulted from the power supply. Therefore, the lamp tube  1  and the end caps  3  could be secured to each other without decreasing the reliability of the LED tube lamp. 
     Furthermore, there is formed an accommodation space between the inner surface of the thermal conductive member  303  and the outer surface of the lamp tube  1  to accommodate the hot melt adhesive  6 , as indicated by the dotted line B in  FIG.  5   . For example, the hot melt adhesive  6  can be filled into the accommodation space at a location where a first hypothetical plane (as indicated by the dotted line B in  FIG.  5   ) being perpendicular to the axial direction of the lamp tube  1  would pass through the thermal conductive member, the hot melt adhesive  6 , and the outer surface of the lamp tube  1 . The hot melt adhesive  6  may have a thickness, for example, of about 0.2 mm to about 0.5 mm. In one embodiment, the hot melt adhesive  6  will be expansive to solidify in and connect with the lamp tube  1  and the end cap  3  to secure both. The transition region  103  brings a height difference between the rear end region  101  and the main body region  102  to avoid the hot melt adhesives  6  being overflowed onto the main body region  102 , and thereby saves manpower to remove the overflowed adhesive and increase the LED tube lamp productivity. The hot melt adhesive  6  is heated by receiving heat from the thermal conductive member  303  to which an electricity from an external heating equipment is applied, and then expands and finally solidifies after cooling, such that the end caps  3  are adhered to the lamp tube  1 . 
     Referring to  FIG.  5   , in one embodiment, the electrically insulating tube  302  of the end cap  3  includes a first tubular part  302   a  and a second tubular part  302   b  connected along an axial direction of the lamp tube  1 . The outer diameter of the second tubular part  302   b  is less than the outer diameter of the first tubular part  302   a . In some embodiments, the outer diameter difference between the first tubular part  302   a  and the second tubular part  302   b  is between about 0.15 mm and about 0.30 mm. The thermal conductive member  303  sleeves over the outer circumferential surface of the second tubular part  302   b . The outer surface of the thermal conductive member  303  is coplanar or substantially flush with respect to the outer circumferential surface of the first tubular part  302   a . For example, the thermal conductive member  303  and the first tubular part  302   a  have substantially uniform exterior diameters from end to end. As a result, the entire end cap  3  and thus the entire LED tube lamp may be smooth with respect to the outer appearance and may have a substantially uniform tubular outer surface, such that the loading during transportation on the entire LED tube lamp is also uniform. In one embodiment, a ratio of the length of the thermal conductive member  303  along the axial direction of the end cap  3  to the axial length of the electrically insulating tube  302  ranges from about 1:2.5 to about 1:5. 
     In one embodiment, for sake of secure adhesion between the end cap  3  and the lamp tube  1 , the second tubular part  302   b  is at least partially disposed around the lamp tube  1 , and the accommodation space further includes a space encompassed by the inner surface of the second tubular part  302   b  and the outer surface of the rear end region  101  of the lamp tube  1 . The hot melt adhesive  6  is at least partially filled in an overlapped region (shown by a dotted line “A” in  FIG.  5   ) between the inner surface of the second tubular part  302   b  and the outer surface of the rear end region  101  of the lamp tube  1 . For example, the hot melt adhesive  6  may be filled into the accommodation space at a location where a second hypothetical plane (shown by the dotted line A in  FIG.  5   ) being perpendicular to the axial direction of the lamp tube  1  would pass through the thermal conductive member  303 , the second tubular part  302   b , the hot melt adhesive  6 , and the rear end region  101 . 
     The hot melt adhesive  6  is not required to completely fill the entire accommodation space as shown in  FIG.  5   , especially where a gap is reserved or formed between the thermal conductive member  303  and the second tubular part  302   b . For example, in some embodiments, the hot melt adhesive  6  can be only partially filled into the accommodation space. During manufacturing of the LED tube lamp, the amount of the hot melt adhesive  6  coated and applied between the thermal conductive member  303  and the rear end region  101  may be appropriately increased, such that in the subsequent heating process, the hot melt adhesive  6  can be caused to expand and flow in between the second tubular part  302   b  and the rear end region  101 , and thereby solidify after cooling to join the second tubular part  302   b  and the rear end region  101 . 
     During fabrication of the LED tube lamp, the rear end region  101  of the lamp tube  1  is inserted into one of the end caps  3 . In some embodiments, the axial length of the inserted portion of the rear end region  101  of the lamp tube  1  accounts for approximately one-third (⅓) to two-thirds (⅔) of the total axial length of the thermal conductive member  303 . One benefit is that, there will be sufficient creepage distance between the hollow conductive pins  301  and the thermal conductive member  303 , and thus it is not easy to form a short circuit leading to dangerous electric shock to individuals. On the other hand, the creepage distance between the hollow conductive pin  301  and the thermal conductive member  303  is increased due to the electrically insulating effect of the electrically insulating tube  302 , and thus a high voltage test is more likely to pass without causing electrical shocks to people. 
     Furthermore, the presence of the second tubular part  302   b  interposed between the hot melt adhesive  6  and the thermal conductive member  303  may reduce the heat from the thermal conductive member  303  to the hot melt adhesive  6 . To help prevent or minimize this problem, referring to  FIG.  4    in one embodiment, the end of the second tubular part  302   b  facing the lamp tube  1  (i.e., away from the first tubular part  302   a ) is circumferentially provided with a plurality of notches  302   c . These notches  302   c  help to increase the contact areas between the thermal conductive member  303  and the hot melt adhesive  6  and therefore provide rapid heat conduction from the thermal conductive member  303  to the hot melt adhesive  6  so as to accelerate the solidification of the hot melt adhesive  6 . Moreover, the hot melt adhesive  6  electrically insulates the thermal conductive member  303  and the lamp tube  1  so that a user would not be electrically shocked when he touches the thermal conductive member  303  connected to a broken lamp tube  1 . 
     The thermal conductive member  303  can be made of various heat conducting materials. The thermal conductive member  303  can be a metal sheet such as an aluminum alloy. The thermal conductive member  303  sleeves the second tubular part  302   b  and can be tubular or ring-shaped. The electrically insulating tube  302  may be made of electrically insulating material, but in some embodiments have low thermal conductivity so as to prevent the heat from reaching the power supply module located inside the end cap  3  and therefore negatively affecting performance of the power supply module. In one embodiment, the electrically insulating tube  302  is a plastic tube. 
     Alternatively, the thermal conductive member  303  may be formed by a plurality of metal plates circumferentially arranged on the tubular part  302   b  with either an equidistant space or a non-equidistant space. 
     The end cap  3  may be designed to have other kinds of structures or include other elements. Referring to  FIG.  6   , the end cap  3  according to another embodiment further includes a magnetic metal member  9  within the electrically insulating tube  302  but excludes the thermal conductive member  3 . The magnetic metal member  9  is fixedly arranged on the inner circumferential surface of the electrically insulating tube  302  and therefore interposed between the electrically insulating tube  302  and the lamp tube  1  such that the magnetic metal member  9  is partially overlapped with the lamp tube  1  in the radial direction. In this embodiment, the whole magnetic metal member  9  is inside the electrically insulating tube  302 , and the hot melt adhesive  6  is coated on the inner surface of the magnetic metal member  9  (the surface of the magnetic metal tube member  9  facing the lamp tube  1 ) and adhered to the outer peripheral surface of the lamp tube  1 . In some embodiments, the hot melt adhesive  6  covers the entire inner surface of the magnetic metal member  9  in order to increase the adhesion area and to improve the stability of the adhesion. 
     Referring to  FIG.  7   , when manufacturing the LED tube lamp of this embodiment, the electrically insulating tube  302  is inserted in an external heating equipment which is in some embodiments an induction coil  11 , so that the induction coil  11  and the magnetic metal member  9  are disposed opposite (or adjacent) to one another along the radially extending direction of the electrically insulating tube  302 . The induction coil  11  is energized and forms an electromagnetic field, and the electromagnetic field induces the magnetic metal member  9  to create an electrical current and become heated. The heat from the magnetic metal member  9  is transferred to the hot melt adhesive  6  to make the hot melt adhesive  6  expansive and flowing and then solidified after cooling, and the bonding for the end cap  3  and the lamp tube  1  can be accomplished. The induction coil  11  may be made, for example, of red copper and composed of metal wires having width of, for example, about 5 mm to about 6 mm to be a circular coil with a diameter, for example, of about 30 mm to about 35 mm, which is a bit greater than the outer diameter of the end cap  3 . Since the end cap  3  and the lamp tube  1  may have the same outer diameters, the outer diameter may change depending on the outer diameter of the lamp tube  1 , and therefore the diameter of the induction coil  11  used can be changed depending on the type of the lamp tube  1  used. As examples, the outer diameters of the lamp tube for T12, T10, T8, T5, T4, and T2 are 38.1 mm, 31.8 mm, 25.4 mm, 16 mm, 12.7 mm, and 6.4 mm, respectively. 
     Furthermore, the induction coil  11  may be provided with a power amplifying unit to increase the alternating current power to about 1 to 2 times the original. In some embodiments, it is better that the induction coil  11  and the electrically insulating tube  302  are coaxially aligned to make energy transfer more uniform. In some embodiments, a deviation value between the axes of the induction coil  11  and the electrically insulating tube  302  is not greater than about 0.05 mm. When the bonding process is complete, the end cap  3  and the lamp tube  1  are moved away from the induction coil. Then, the hot melt adhesive  6  absorbs the energy to be expansive and flowing and solidified after cooling. In one embodiment, the magnetic metal member  9  can be heated to a temperature of about 250 to about 300 degrees Celsius; the hot melt adhesive  6  can be heated to a temperature of about 200 to about 250 degrees Celsius. The material of the hot melt adhesive is not limited here, and a material for allowing the hot melt adhesive to immediately solidify when absorbing heat energy can also be used. 
     In one embodiment, the induction coil  11  may be fixed in position to allow the end cap  3  and the lamp tube  1  to be moved into the induction coil  11  such that the hot melt adhesive  6  is heated to expand and flow and then solidify after cooling when the end cap  3  is again moved away from the induction coil  11 . Alternatively, the end cap  3  and the lamp tube  1  may be fixed in position to allow the induction coil  11  to be moved to encompass the end cap  3  such that the hot melt adhesive  6  is heated to expand and flow and then solidify after cooling when the induction coil  11  is again moved away from the end cap  3 . In one embodiment, the external heating equipment for heating the magnetic metal member  9  is provided with a plurality of devices the same as the induction coils  11 , and the external heating equipment moves relative to the end cap  3  and the lamp tube  1  during the heating process. In this way, the external heating equipment moves away from the end cap  3  when the heating process is completed. However, the length of the lamp tube  1  is far greater than the length of the end cap  3  and may be up to above 240 cm in some special appliances, and this may cause bad connection between the end cap  3  and the lamp tube  1  during the process that the lamp tube  1  accompany with the end cap  3  to relatively enter or leave the induction coil  11  in the back and for the direction as mentioned above when a position error exists. 
     Referring to  FIG.  44   , an external heating equipment  110  having a plurality sets of upper and lower semicircular fixtures  11   a  is provided to achieve same heating effect as that brought by the induction coils  11 . In this way, the above-mentioned damage risk due to the relative movement in back-and-forth direction can be reduced. The upper and lower semicircular fixtures  11   a  each has a semicircular coil made by winding a metal wire of, for example, about 5 mm to about 6 mm wide. The combination of the upper and lower semicircular fixtures form a ring with a diameter, for example, of about 30 mm to about 35 mm, and the inside semicircular coils form a closed loop to become the induction coil  11  as mentioned. In this embodiment, the end cap  3  and the lamp tube  1  do not relatively move in the back-and-forth manner, but roll into the notch of the lower semicircular fixture. Specifically, an end cap  3  accompanied with a lamp tube  1  initially roll on a production line, and then the end cap  3  rolls into the notch of a lower semicircular fixture, and then the upper and the lower semicircular fixtures are combined to form a closed loop, and the fixtures are detached when heating is completed. This method reduces the need for high position precision and yield problems in production. 
     Referring to  FIG.  6   , the electrically insulating tube  302  is further divided into two parts, namely a first tubular part  302   d  and a second tubular part  302   e , i.e. the remaining part. In order to provide better support of the magnetic metal member  9 , an inner diameter of the first tubular part  302   d  for supporting the magnetic metal member  9  is larger than the inner diameter of the second tubular part  302   e  which does not have the magnetic metal member  9 , and a stepped structure is formed at the connection of the first tubular part  302   d  and the second tubular part  302   e . In this way, an end of the magnetic metal member  9  as viewed in an axial direction is abutted against the stepped structure such that the entire inner surface of the end cap is smooth and plain. Additionally, the magnetic metal member  9  may be of various shapes, e.g., a sheet-like or tubular-like structure being circumferentially arranged or the like, where the magnetic metal member  9  is coaxially arranged with the electrically insulating tube  302 . 
     Referring to  FIGS.  8  and  9   , the electrically insulating tube may be further formed with a supporting portion  313  on the inner surface of the electrically insulating tube  302  to be extending inwardly such that the magnetic metal member  9  is axially abutted against the upper edge of the supporting portion  313 . In some embodiments, the thickness of the supporting portion  313  along the radial direction of the electrically insulating tube  302  is between 1 mm to 2 mm. The electrically insulating tube  302  may be further formed with a protruding portion  310  on the inner surface of the electrically insulating tube  302  to be extending inwardly such that the magnetic metal member  9  is radially abutted against the side edge of the protruding portion  310  and that the outer surface of the magnetic metal member  9  and the inner surface of the electrically insulating tube  302  is spaced apart with a gap. The thickness of the protruding portion  310  along the radial direction of the electrically insulating tube  302  is less than the thickness of the supporting portion  313  along the radial direction of the electrically insulating tube  302  and in some embodiments be 0.2 mm to 1 mm in an embodiment. 
     Referring to  FIG.  9   , the protruding portion  310  and the supporting portion are connected along the axial direction, and the magnetic metal member  9  is axially abutted against the upper edge of the supporting portion  313  while radially abutted against the side edge of the protruding portion  310  such that at least part of the protruding portion  310  intervenes between the magnetic metal member  9  and the electrically insulating tube  302 . The protruding portion  310  may be arranged along the circumferential direction of the electrically insulating tube  302  to have a circular configuration. Alternatively, the protruding portion  310  may be in the form of a plurality of bumps arranged on the inner surface of the electrically insulating tube  302 . The bumps may be equidistantly or non-equidistantly arranged along the inner circumferential surface of the electrically insulating tube  302  as long as the outer surface of the magnetic metal member  9  and the inner surface of the electrically insulating tube  302  are in a minimum contact and simultaneously hold the hot melt adhesive  6 . In other embodiments, an entirely metal made end cap  3  could be used with an insulator disposed under the hollow conductive pin to endure the high voltage. 
     Referring to  FIG.  10   , in one embodiment, the magnetic metal member  9  can have one or more openings  91  that are circular. However, the openings  91  may instead be, for example, oval, square, star shaped, etc., as long as the contact area between the magnetic metal member  9  and the inner peripheral surface of the electrically insulating tube  302  can be reduced and the function of the magnetic metal member  9  to heat the hot melt adhesive  6  can be performed. In some embodiments, the openings  91  occupy about 10% to about 50% of the surface area of the magnetic metal member  9 . The opening  91  can be arranged circumferentially on the magnetic metal member  9  in an equidistantly spaced or non-equidistantly spaced manner. 
     Referring to  FIG.  11   , in other embodiments, the magnetic metal member  9  has an indentation/embossment  93  on a surface facing the electrically insulating tube  302 . The embossment is raised from the inner surface of the magnetic metal member  9 , while the indentation is depressed under the inner surface of the magnetic metal member  9 . The indentation/embossment reduces the contact area between the inner peripheral surface of the electrically insulating tube  302  and the outer surface of the magnetic metal member  9  while maintaining the function of melting and curing the hot melt adhesive  6 . In sum, the surface of the magnetic metal member  9  can be configured to have openings, indentations, or embossments or any combination thereof to achieve the goal of reducing the contact area between the inner peripheral surface of the electrically insulating tube  302  and the outer surface of the magnetic metal member  9 . At the same time, the firm adhesion between the magnetic metal member  9  and the lamp tube  1  should be secured to accomplish the heating and solidification of the hot melt adhesive  6 . 
     Referring to  FIG.  12   , in one embodiment, the magnetic metal member  9  is a circular ring. Referring to  FIG.  13   , in another embodiment, the magnetic metal member  9  is a non-circular ring such as but not limited to an oval ring. When the magnetic metal member  9  is an oval ring, the minor axis of the oval ring is slightly larger than the outer diameter of the end region of the lamp tube  1  such that the contact area of the inner peripheral surface of the electrically insulating tube  302  and the outer surface of the magnetic metal member  9  is reduced and the function of melting and curing the hot melt adhesive  6  still performs properly. For example, the inner surface of the electrically insulating tube  302  may be formed with supporting portion  313  and the magnetic metal member  9  in a non-circular ring shape is seated on the supporting portion  313 . Thus, the contact area of the outer surface of the magnetic metal member  9  and the inner surface of the electrically insulating tube  302  could be reduced while that the function of solidifying the hot melt adhesive  6  could be performed. In other embodiments, the magnetic metal member  9  can be disposed on the outer surface of the end cap  3  to replace the thermal conductive member  303  as shown in  FIG.  5    and to perform the function of heating and solidifying the hot melt adhesive  6  via electromagnetic induction. 
     Referring to  FIGS.  45  to  47   , in other embodiments, the magnetic metal member  9  may be omitted. Instead, in some embodiments, the hot melt adhesive  6  has a predetermined proportion of high permeability powders  65  having relative permeability ranging, for example, from about 10 2  to about 10 6 . The powders can be used to replace the calcite powders originally included in the hot melt adhesive  6 , and in certain embodiments, a volume ratio of the high permeability powders  65  to the calcite powders may be about 1:3˜1:1. In some embodiments, the material of the high permeability powders  65  is one of iron, nickel, cobalt, alloy thereof, or any combination thereof; the weight percentage of the high permeability powders  65  with respect to the hot melt adhesive is about 10% to about 50%; and/or the powders may have mean particle size of about 1 to about 30 micrometers. Such a hot melt adhesive  6  allows the end cap  3  and the lamp tube  1  to adhere together and be qualified in a destruction test, a torque test, and a bending test. Generally speaking, the bending test standard for the end cap of the LED tube lamp is greater than 5 newton-meters (Nt-m), while the torque test standard is greater than 1.5 newton-meters (Nt-m). In one embodiment, upon the ratio of the high permeability powders  65  to the hot melt adhesive  6  and the magnetic flux applied, the end cap  3  and the end of the lamp tube  1  secured by using the hot melt adhesive  6  are qualified in a torque test of 1.5 to 5 newton-meters (Nt-m) and a bending test of 5 to 10 newton-meters (Nt-m). The induction coil  11  is first switched on and allow the high permeability powders uniformly distributed in the hot melt adhesive  6  to be charged, and therefore allow the hot melt adhesive  6  to be heated to be expansive and flowing and then solidified after cooling. Thereby, the goal of adhering the end cap  3  onto the lamp tube  1  is achieved. 
     Referring to  FIGS.  45  to  47   , the high permeability powders  65  may have different distribution manners in the hot melt adhesive  6 . As shown in  FIG.  45   , the high permeability powders  65  have mean particle size of about 1 to about 5 micrometers and are distributed uniformly in the hot melt adhesive  6 . When such a hot melt adhesive  6  is coated on the inner surface of the end cap  3 , though the high permeability powders  65  cannot form a closed loop due to the uniform distribution, they can still be heated due to magnetic hysteresis in the electromagnetic field, so as to heat the hot melt adhesive  6 . As shown in  FIG.  46   , the high permeability powders  65  have mean particle size of about 1 to about 5 micrometers and are distributed randomly in the hot melt adhesive  6 . When such a hot melt adhesive  6  is coated on the inner surface of the end cap  3 , the high permeability powders  65  form a closed loop due to the random distribution; they can be heated due to magnetic hysteresis or the closed loop in the electromagnetic field, so as to heat the hot melt adhesive  6 . As shown in  FIG.  47   , the high permeability powders  65  have mean particle size of about 5 to about 30 micrometers and are distributed randomly in the hot melt adhesive  6 . When such a hot melt adhesive  6  is coated on the inner surface of the end cap  3 , the high permeability powders  65  form a closed loop due to the random distribution; they can be heated due to magnetic hysteresis or the closed loop in the electromagnetic field, so as to heat the hot melt adhesive  6 . Accordingly, depending on the adjustment of the particle size, the distribution density and the distribution manner of the high permeability powders  65 , and the electromagnetic flux applied to the end cap  3 , the heating temperature of the hot melt adhesive  6  can be controlled. In one embodiment, the hot melt adhesive  6  is flowing and solidified after cooling from a temperature of about 200 to about 250 degrees Celsius. In another embodiment, the hot melt adhesive  6  is immediately solidified at a temperature of about 200 to about 250 degrees Celsius. 
     Referring to  FIGS.  14  and  39   , in one embodiment, an end cap  3 ′ has a pillar  312  at one end, the top end of the pillar  312  is provided with an opening having a groove  314  of, for example 0.1±1% mm depth at the periphery thereof for positioning a conductive lead  53  as shown in  FIG.  39   . The conductive lead  53  passes through the opening on top of the pillar  312  and has its end bent to be disposed in the groove  314 . After that, a conductive metallic cap  311  covers the pillar  312  such that the conductive lead  53  is fixed between the pillar  312  and the conductive metallic cap  311 . In some embodiments, the inner diameter of the conductive metallic cap  311  is 7.56±5% mm, the outer diameter of the pillar  312  is 7.23±5% mm, and the outer diameter of the conductive lead  53  is 0.5±1% mm. Nevertheless, the mentioned sizes are not limited here once that the conductive metallic cap  311  closely covers the pillar  312  without using extra adhesives and therefore completes the electrical connection between the power supply  5  and the conductive metallic cap  311 . 
     Referring to  FIGS.  1 B,  3 ,  12 , and  13   , in one embodiment, the end cap  3  may have openings  304  to dissipate heat generated by the power supply modules inside the end cap  3  so as to prevent a high temperature condition inside the end cap  3  that might reduce reliability. In some embodiments, the openings are in a shape of an arc; especially in a shape of three arcs with different length. In one embodiment, the openings are in a shape of three arcs with gradually varying length. The openings on the end cap  3  can be in any one of the above-mentioned shape or any combination thereof. 
     In other embodiments, the end cap  3  is provided with a socket (not shown) for installing the power supply module. 
     Referring to  FIG.  17   , in one embodiment, the lamp tube  1  further has a diffusion film  13  coated and bonded to the inner surface thereof so that the light outputted or emitted from the LED light sources  202  is diffused by the diffusion film  13  and then pass through the lamp tube  1 . The diffusion film  13  can be in form of various types, such as a coating onto the inner surface or outer wall of the lamp tube  1 , or a diffusion coating layer (not shown) coated at the surface of each LED light source  202 , or a separate membrane covering the LED light source  202 . 
     Referring again to  FIG.  17   , in one embodiment, when the diffusion film  13  is in the form of a sheet, it covers but is not in contact with the LED light sources  202 . The diffusion film  13  in the form of a sheet is usually called an optical diffusion sheet or board, usually a composite made of mixing diffusion particles into polystyrene (PS), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and/or polycarbonate (PC), and/or any combination thereof. The light passing through such composite is diffused to expand in a wide range of space such as a light emitted from a plane source, and therefore makes the brightness of the LED tube lamp uniform. 
     In alternative embodiments, the diffusion film  13  is in form of an optical diffusion coating, which is composed of any one of calcium carbonate, halogen calcium phosphate and aluminum oxide, or any combination thereof. When the optical diffusion coating is made from a calcium carbonate with suitable solution, an excellent light diffusion effect and transmittance to exceed 90% can be obtained. Furthermore, the diffusion film  13  in form of an optical diffusion coating may be applied to an outer surface of the rear end region  101  having the hot melt adhesive  6  to produce increased friction resistance between the end cap  3  and the rear end region  101 . Compared with an example without any optical diffusion coating, the rear end region  101  having the diffusion film  13  is beneficial, for example for preventing accidental detachment of the end cap  3  from the lamp tube  1 . 
     In one embodiment, the composition of the diffusion film  13  in form of the optical diffusion coating includes calcium carbonate, strontium phosphate (e.g., CMS-5000, white powder), thickener, and a ceramic activated carbon (e.g., ceramic activated carbon SW-C, which is a colorless liquid). Specifically, in one example, such an optical diffusion coating on the inner circumferential surface of the glass tube has an average thickness ranging between about 20 and about 30 μm. A light transmittance of the diffusion film  13  using this optical diffusion coating is about 90%. Generally speaking, the light transmittance of the diffusion film  13  ranges from 85% to 96%. In addition, this diffusion film  13  can also provide electrical isolation for reducing risk of electric shock to a user upon breakage of the lamp tube  1 . Furthermore, the diffusion film  13  provides an improved illumination distribution uniformity of the light outputted by the LED light sources  202  such that the light can illuminate the back of the light sources  202  and the side edges of the bendable circuit sheet so as to avoid the formation of dark regions inside the lamp tube  1  and improve the illumination comfort. In another possible embodiment, the light transmittance of the diffusion film can be 92% to 94% while the thickness ranges from about 200 to about 300 μm. 
     In another embodiment, the optical diffusion coating can also be made of a mixture including a calcium carbonate-based substance, some reflective substances like strontium phosphate or barium sulfate, a thickening agent, ceramic activated carbon, and deionized water. The mixture is coated on the inner circumferential surface of the glass tube and has an average thickness ranging between about 20 and about 30 μm. In view of the diffusion phenomena in microscopic terms, light is reflected by particles. The particle size of the reflective substance such as strontium phosphate or barium sulfate will be much larger than the particle size of the calcium carbonate. Therefore, adding a small amount of reflective substance in the optical diffusion coating can effectively increase the diffusion effect of light. 
     In other embodiments, halogen calcium phosphate or aluminum oxide can also serve as the main material for forming the diffusion film  13 . The particle size of the calcium carbonate is, for example, about 2 to 4 μm, while the particle size of the halogen calcium phosphate and aluminum oxide are about 4 to 6 μm and 1 to 2 μm, respectively. When the light transmittance is required to be 85% to 92%, the average thickness for the optical diffusion coating mainly having the calcium carbonate may be about 20 to about 30 μm, while the average thickness for the optical diffusion coating mainly having the halogen calcium phosphate may be about 25 to about 35 μm, and/or the average thickness for the optical diffusion coating mainly having the aluminum oxide may be about 10 to about 15 μm. However, when the required light transmittance is up to 92% and even higher, the optical diffusion coating mainly having the calcium carbonate, the halogen calcium phosphate, or the aluminum oxide should be even thinner. 
     The main material and the corresponding thickness of the optical diffusion coating can be decided according to the place for which the lamp tube  1  is used and the light transmittance required. It is noted that the higher the light transmittance of the diffusion film is required, the more apparent the grainy visual of the light sources is. 
     Referring to  FIG.  17   , the inner circumferential surface of the lamp tube  1  may also be provided or bonded with a reflective film  12 . The reflective film  12  is provided around the LED light sources  202  and occupies a portion of an area of the inner circumferential surface of the lamp tube  1  arranged along the circumferential direction thereof. As shown in  FIG.  17   , the reflective film  12  is disposed at two sides of the LED light strip  2  extending along a circumferential direction of the lamp tube  1 . The LED light strip  2  is basically in a middle position of the lamp tube  1  and between the two reflective films  12 . The reflective film  12 , when viewed by a person looking at the lamp tube from the side (in the X-direction shown in  FIG.  17   ), serves to block the LED light sources  202 , so that the person does not directly see the LED light sources  202 , thereby reducing the visual graininess effect. On the other hand, that the lights emitted from the LED light sources  202  are reflected by the reflective film  12  facilitates the divergence angle control of the LED tube lamp, so that more lights illuminate toward directions without the reflective film  12 , such that the LED tube lamp has higher energy efficiency when providing the same level of illumination performance. 
     Specifically, the reflective film  12  is provided on the inner peripheral surface of the lamp tube  1  and has an opening  12   a  configured to accommodate the LED light strip  2 . The size of the opening  12   a  is the same or slightly larger than the size of the LED light strip  2 . During assembly, the LED light sources  202  are mounted on the LED light strip  2  (a bendable circuit sheet) provided on the inner surface of the lamp tube  1 , and then the reflective film  12  is adhered to the inner surface of the lamp tube  1 , so that the opening  12   a  of the reflective film  12  correspondingly matches the LED light strip  2  in a one-to-one relationship, and the LED light strip  2  is exposed to the outside of the reflective film  12 . 
     In one embodiment, the reflectance of the reflective film  12  is generally at least greater than 85%, in some embodiments greater than 90%, and in some embodiments greater than 95%, to be most effective. In one embodiment, the reflective film  12  extends circumferentially along the length of the lamp tube  1  occupying about 30% to 50% of the inner surface area of the lamp tube  1 . In other words, a ratio of a circumferential length of the reflective film  12  along the inner circumferential surface of the lamp tube  1  to a circumferential length of the lamp tube  1  is about 0.3 to 0.5. In the illustrated embodiment of  FIG.  17   , the reflective film  12  is disposed substantially in the middle along a circumferential direction of the lamp tube  1 , so that the two distinct portions or sections of the reflective film  12  disposed on the two sides of the LED light strip  2  are substantially equal in area. The reflective film  12  may be made of PET with some reflective materials such as strontium phosphate or barium sulfate or any combination thereof, with a thickness between about 140 μm and about 350 μm or between about 150 μm and about 220 μm for a more preferred effect in some embodiments. As shown in  FIG.  18   , in other embodiments, the reflective film  12  may be provided along the circumferential direction of the lamp tube  1  on only one side of the LED light strip  2  while occupying the same percentage of the inner surface area of the lamp tube  1  (e.g., 15% to 25% for the one side). Alternatively, as shown in  FIGS.  19  and  20   , the reflective film  12  may be provided without any opening, and the reflective film  12  is directly adhered or mounted to the inner surface of the lamp tube  1  and followed by mounting or fixing the LED light strip  2  on the reflective film  12  such that the reflective film  12  positioned on one side or two sides of the LED light strip  2 . 
     In the above mentioned embodiments, various types of the reflective film  12  and the diffusion film  13  can be adopted to accomplish optical effects including single reflection, single diffusion, and/or combined reflection-diffusion. For example, the lamp tube  1  may be provided with only the reflective film  12 , and no diffusion film  13  is disposed inside the lamp tube  1 , such as shown in  FIGS.  19 ,  20 , and  21   . 
     In other embodiments, the width of the LED light strip  2  (along the circumferential direction of the lamp tube) can be widened to occupy a circumference area of the inner circumferential surface of the lamp tube  1 . Since the LED light strip  2  has on its surface a circuit protective layer made of an ink which can reflect lights, the widened part of the LED light strip  2  functions like the reflective film  12  as mentioned above. In some embodiments, a ratio of the length of the LED light strip  2  along the circumferential direction to the circumferential length of the lamp tube  1  is about 0.3 to 0.5. The light emitted from the light sources could be concentrated by the reflection of the widened part of the LED light strip  2 . 
     In other embodiments, the inner surface of the glass made lamp tube may be coated totally with the optical diffusion coating, or partially with the optical diffusion coating (where the reflective film  12  is coated have no optical diffusion coating). No matter in what coating manner, in some embodiments, it is more desirable that the optical diffusion coating be coated on the outer surface of the rear end region of the lamp tube  1  so as to firmly secure the end cap  3  with the lamp tube  1 . 
     In the present invention, the light emitted from the light sources may be processed with the abovementioned diffusion film, reflective film, other kinds of diffusion layer sheets, adhesive film, or any combination thereof. 
     Referring again to  FIG.  1 B , the LED tube lamp according to some embodiments of present invention also includes an adhesive sheet  4 , an insulation adhesive sheet  7 , and an optical adhesive sheet  8 . The LED light strip  2  is fixed by the adhesive sheet  4  to an inner circumferential surface of the lamp tube  1 . The adhesive sheet  4  may be but is not limited to a silicone adhesive. The adhesive sheet  4  may be in form of several short pieces or a long piece. Various kinds of the adhesive sheet  4 , the insulation adhesive sheet  7 , and the optical adhesive sheet  8  can be combined to constitute various embodiments of the present invention. 
     The insulation adhesive sheet  7  is coated on the surface of the LED light strip  2  that faces the LED light sources  202  so that the LED light strip  2  is not exposed and thus electrically insulated from the outside environment. In application of the insulation adhesive sheet  7 , a plurality of through holes  71  on the insulation adhesive sheet  7  are reserved to correspondingly accommodate the LED light sources  202  such that the LED light sources  202  are mounted in the through holes  701 . The material composition of the insulation adhesive sheet  7  may include, for example vinyl silicone, hydrogen polysiloxane and aluminum oxide. The insulation adhesive sheet  7  has a thickness, for example, ranging from about 100 μm to about 140 μm (micrometers). The insulation adhesive sheet  7  having a thickness less than 100 μm typically does not produce sufficient insulating effect, while the insulation adhesive sheet  7  having a thickness more than 140 μm may result in material waste. 
     The optical adhesive sheet  8 , which is a clear or transparent material, is applied or coated on the surface of the LED light source  202  in order to ensure optimal light transmittance. After being applied to the LED light sources  202 , the optical adhesive sheet  8  may have a granular, strip-like or sheet-like shape. The performance of the optical adhesive sheet  8  depends on its refractive index and thickness. The refractive index of the optical adhesive sheet  8  is in some embodiments between 1.22 and 1.6. In some embodiments, it is better for the optical adhesive sheet  8  to have a refractive index being a square root of the refractive index of the housing or casing of the LED light source  202 , or the square root of the refractive index of the housing or casing of the LED light source  202  plus or minus 15%, to contribute better light transmittance. The housing/casing of the LED light sources  202  is a structure to accommodate and carry the LED dies (or chips) such as a LED lead frame  202   b  as shown in  FIG.  37   . The refractive index of the optical adhesive sheet  8  may range from 1.225 to 1.253. In some embodiments, the thickness of the optical adhesive sheet  8  may range from 1.1 mm to 1.3 mm. The optical adhesive sheet  8  having a thickness less than 1.1 mm may not be able to cover the LED light sources  202 , while the optical adhesive sheet  8  having a thickness more than 1.3 mm may reduce light transmittance and increases material cost. 
     In some embodiments, in the process of assembling the LED light sources to the LED light strip, the optical adhesive sheet  8  is first applied on the LED light sources  202 ; then the insulation adhesive sheet  7  is coated on one side of the LED light strip  2 ; then the LED light sources  202  are fixed or mounted on the LED light strip  2 ; the other side of the LED light strip  2  being opposite to the side of mounting the LED light sources  202  is bonded and affixed to the inner surface of the lamp tube  1  by the adhesive sheet  4 ; finally, the end cap  3  is fixed to the end portion of the lamp tube  1 , and the LED light sources  202  and the power supply  5  are electrically connected by the LED light strip  2 . As shown in the embodiment of  FIG.  22   , the bendable circuit sheet  2  passes the transition region  103  to be soldered or traditionally wire-bonded with the power supply  5 , and then the end cap  3  having the structure as shown in  FIG.  3  or  4    or  FIG.  6    is adhered to the strengthened transition region  103  via methods as shown in  FIG.  5    or  FIG.  7   , respectively to form a complete LED tube lamp. 
     In this embodiment, the LED light strip  2  is fixed by the adhesive sheet  4  to an inner circumferential surface of the lamp tube  1 , so as to increase the light illumination angle of the LED tube lamp and broaden the viewing angle to be greater than 330 degrees. By means of applying the insulation adhesive sheet  7  and the optical adhesive sheet  8 , electrical insulation of the entire light strip  2  is accomplished such that electrical shock would not occur even when the lamp tube  1  is broken and therefore safety could be improved. 
     Furthermore, the inner peripheral surface or the outer circumferential surface of the glass made lamp tube  1  may be covered or coated with an adhesive film (not shown) to isolate the inside from the outside of the glass made lamp tube  1  when the glass made lamp tube  1  is broken. In this embodiment, the adhesive film is coated on the inner peripheral surface of the lamp tube  1 . The material for the coated adhesive film includes, for example, methyl vinyl silicone oil, hydro silicone oil, xylene, and calcium carbonate, wherein xylene is used as an auxiliary material. The xylene will be volatilized and removed when the coated adhesive film on the inner surface of the lamp tube  1  solidifies or hardens. The xylene is mainly used to adjust the capability of adhesion and therefore to control the thickness of the coated adhesive film. 
     In one embodiment, the thickness of the coated adhesive film is preferably between about 100 and about 140 micrometers (μm). The adhesive film having a thickness being less than 100 micrometers may not have sufficient shatterproof capability for the glass tube, and the glass tube is thus prone to crack or shatter. The adhesive film having a thickness being larger than 140 micrometers may reduce the light transmittance and also increase material cost. The thickness of the coated adhesive film may be between about 10 and about 800 micrometers (μm) when the shatterproof capability and the light transmittance are not strictly demanded. 
     In one embodiment, the inner peripheral surface or the outer circumferential surface of the glass made lamp tube  1  is coated with an adhesive film such that the broken pieces are adhered to the adhesive film when the glass made lamp tube is broken. Therefore, the lamp tube  1  would not be penetrated to form a through hole connecting the inside and outside of the lamp tube  1  and thus prevents a user from touching any charged object inside the lamp tube  1  to avoid electrical shock. In addition, the adhesive film is able to diffuse light and allows the light to transmit such that the light uniformity and the light transmittance of the entire LED tube lamp increases. The adhesive film can be used in combination with the adhesive sheet  4 , the insulation adhesive sheet  7  and the optical adhesive sheet  8  to constitute various embodiments of the present invention. As the LED light strip  2  is configured to be a bendable circuit sheet, no coated adhesive film is thereby required. 
     Furthermore, the light strip  2  may be an elongated aluminum plate, FR 4 board, or a bendable circuit sheet. When the lamp tube  1  is made of glass, adopting a rigid aluminum plate or FR4 board would make a broken lamp tube, e.g., broken into two parts, remain a straight shape so that a user may be under a false impression that the LED tube lamp is still usable and fully functional, and it is easy for him to incur electric shock upon handling or installation of the LED tube lamp. Because of added flexibility and bendability of the flexible substrate for the LED light strip  2 , the problem faced by the aluminum plate, FR4 board, or conventional 3-layered flexible board having inadequate flexibility and bendability, are thereby addressed. In certain embodiments, a bendable circuit sheet is adopted as the LED light strip  2  for that such a LED light strip  2  would not allow a ruptured or broken lamp tube to maintain a straight shape and therefore instantly inform the user of the disability of the LED tube lamp and avoid possibly incurred electrical shock. The following are further descriptions of the bendable circuit sheet used as the LED light strip  2 . 
     Referring to  FIG.  23   , in one embodiment, the LED light strip  2  includes a bendable circuit sheet having a conductive wiring layer  2   a  and a dielectric layer  2   b  that are arranged in a stacked manner, wherein the wiring layer  2   a  and the dielectric layer  2   b  have same areas. The LED light source  202  is disposed on one surface of the wiring layer  2   a , the dielectric layer  2   b  is disposed on the other surface of the wiring layer  2   a  that is away from the LED light sources  202 . The wiring layer  2   a  is electrically connected to the power supply  5  to carry direct current (DC) signals. Meanwhile, the surface of the dielectric layer  2   b  away from the wiring layer  2   a  is fixed to the inner circumferential surface of the lamp tube  1  by means of the adhesive sheet  4 . The wiring layer  2   a  can be a metal layer or a power supply layer including wires such as copper wires. 
     In another embodiment, the outer surface of the wiring layer  2   a  or the dielectric layer  2   b  may be covered with a circuit protective layer made of ink that functions to resist soldering and increase reflectivity. Alternatively, the dielectric layer can be omitted and the wiring layer can be directly bonded to the inner circumferential surface of the lamp tube, and the outer surface of the wiring layer  2   a  is coated with the circuit protective layer. Whether the wiring layer  2   a  has a one-layered, or two-layered structure, the circuit protective layer can be adopted. In some embodiments, the circuit protective layer is disposed only on one side/surface of the LED light strip  2 , such as the surface having the LED light source  202 . In some embodiments, the bendable circuit sheet is a one-layered structure made of just one wiring layer  2   a , or a two-layered structure made of one wiring layer  2   a  and one dielectric layer  2   b , and thus is more bendable or flexible to curl when compared with the conventional three-layered flexible substrate (one dielectric layer sandwiched with two wiring layers). As a result, the bendable circuit sheet of the LED light strip  2  can be installed in a lamp tube with a customized shape or non-tubular shape, and fitly mounted to the inner surface of the lamp tube. The bendable circuit sheet closely mounted to the inner surface of the lamp tube is preferable in some cases. In addition, using fewer layers of the bendable circuit sheet improves the heat dissipation and lowers the material cost. 
     Nevertheless, the bendable circuit sheet is not limited to being one-layered or two-layered; in other embodiments, the bendable circuit sheet may include multiple layers of the wiring layers  2   a  and multiple layers of the dielectric layers  2   b , in which the dielectric layers  2   b  and the wiring layers  2   a  are sequentially stacked in a staggered manner, respectively. These stacked layers are away from the surface of the outermost wiring layer  2   a  which has the LED light source  202  disposed thereon and is electrically connected to the power supply  5 . Moreover, the length of the bendable circuit sheet is greater than the length of the lamp tube. 
     Referring to  FIG.  48   , in one embodiment, the LED light strip  2  includes a bendable circuit sheet having in sequence a first wiring layer  2   a , a dielectric layer  2   b , and a second wiring layer  2   c . The thickness of the second wiring layer  2   c  is greater than that of the first wiring layer  2   a , and the length of the LED light strip  2  is greater than that of the lamp tube  1 . The end region of the light strip  2  extending beyond the end portion of the lamp tube  1  without disposition of the light source  202  is formed with two separate through holes  203  and  204  to respectively electrically communicate the first wiring layer  2   a  and the second wiring layer  2   c . The through holes  203  and  204  are not communicated to each other to avoid short. 
     In this way, the greater thickness of the second wiring layer  2   c  allows the second wiring layer  2   c  to support the first wiring layer  2   a  and the dielectric layer  2   b , and at the same time allow the LED light strip  2  to be mounted onto the inner circumferential surface without being subject to shifting or deformation, thus improving the yield rate of the product. In addition, the first wiring layer  2   a  and the second wiring layer  2   c  are in electrical communication such that the circuit layout of the first wiring layer  2   a  can be extended downward to the second wiring layer  2   c  to reach the circuit layout of the entire LED light strip  2 . Moreover, since the area for the circuit layout becomes two-layered, the area of each single layer and therefore the width of the LED light strip  2  can be reduced such that more LED light strips  2  can be put on a production line to increase productivity. 
     Furthermore, the first wiring layer  2   a  and the second wiring layer  2   c  of the end region of the LED light strip  2  that extends beyond the end portion of the lamp tube  1  without disposition of the light source  202  can be used to accomplish the circuit layout of a power supply module so that the power supply module can be directly disposed on the bendable circuit sheet of the LED light strip  2 . 
     Referring to  FIG.  1 B , in one embodiment, the LED light strip  2  has a plurality of LED light sources  202  mounted thereon, and the end cap  3  has a power supply  5  installed therein. The LED light sources  202  and the power supply  5  are electrically connected by the LED light strip  2 . The power supply  5  may be a single integrated unit (i.e., all of the power supply components are integrated into one module unit) installed in one end cap  3 . Alternatively, the power supply  5  may be divided into two separate units (i.e. the power supply components are divided into two parts) installed in two end caps  3 , respectively. When only one end of the lamp tube  1  is strengthened by a glass tempering process, it may be preferable that the power supply  5  is a single integrated unit and installed in the end cap  3  corresponding to the strengthened end of the lamp tube  1 . 
     The power supply  5  can be fabricated by various ways. For example, the power supply  5  may be an encapsulation body formed by injection molding a silica gel with high thermal conductivity such as being greater than 0.7 w/m·k. This kind of power supply has advantages of high electrical insulation, high heat dissipation, and regular shape to match other components in an assembly. Alternatively, the power supply  5  in the end caps may be a printed circuit board having components that are directly exposed or packaged by a heat shrink sleeve. The power supply  5  according to some embodiments of the present invention can be a single printed circuit board provided with a power supply module as shown in  FIG.  23    or a single integrated unit as shown in  FIG.  38   . 
     Referring to  FIGS.  1 B and  38   , in one embodiment of the present invention, the power supply  5  is provided with a male plug  51  at one end and a metal pin  52  at the other end, one end of the LED light strip  2  is correspondingly provided with a female plug  201 , and the end cap  3  is provided with a hollow conductive pin  301  to be connected with an outer electrical power source. Specifically, the male plug  51  is fittingly inserted into the female plug  201  of the LED light strip  2 , while the metal pins  52  are fittingly inserted into the hollow conductive pins  301  of the end cap  3 . The male plug  51  and the female plug  201  function as a connector between the power supply  5  and the LED light strip  2 . Upon insertion of the metal pin  502 , the hollow conductive pin  301  is punched with an external punching tool to slightly deform such that the metal pin  502  of the power supply  5  is secured and electrically connected to the hollow conductive pin  301 . Upon turning on the electrical power, the electrical current passes in sequence through the hollow conductive pin  301 , the metal pin  502 , the male plug  501 , and the female plug  201  to reach the LED light strip  2  and go to the LED light sources  202 . However, the power supply  5  of the present invention is not limited to the modular type as shown in  FIG.  38   . The power supply  5  may be a printed circuit board provided with a power supply module and electrically connected to the LED light strip  2  via the abovementioned male plug  51  and female plug  52  combination. 
     In another embodiment, a traditional wire bonding technique can be used instead of the male plug  51  and the female plug  52  for connecting any kind of the power supply  5  and the light strip  2 . Furthermore, the wires may be wrapped with an electrically insulating tube to protect a user from being electrically shocked. However, the bonded wires tend to be easily broken during transportation and can therefore cause quality issues. 
     In still another embodiment, the connection between the power supply  5  and the LED light strip  2  may be accomplished via tin soldering, rivet bonding, or welding. One way to secure the LED light strip  2  is to provide the adhesive sheet  4  at one side thereof and adhere the LED light strip  2  to the inner surface of the lamp tube  1  via the adhesive sheet  4 . Two ends of the LED light strip  2  can be either fixed to or detached from the inner surface of the lamp tube  1 . 
     In case that two ends of the LED light strip  2  are fixed to the inner surface of the lamp tube  1 , it may be preferable that the bendable circuit sheet of the LED light strip  2  is provided with the female plug  201  and the power supply is provided with the male plug  51  to accomplish the connection between the LED light strip  2  and the power supply  5 . In this case, the male plug  51  of the power supply  5  is inserted into the female plug  201  to establish electrical connection. 
     In case that two ends of the LED light strip  2  are detached from the inner surface of the lamp tube and that the LED light strip  2  is connected to the power supply  5  via wire-bonding, any movement in subsequent transportation is likely to cause the bonded wires to break. Therefore, a preferable option for the connection between the light strip  2  and the power supply  5  could be soldering. Specifically, referring to  FIG.  22   , the ends of the LED light strip  2  including the bendable circuit sheet are arranged to pass over the strengthened transition region  103  and directly soldering bonded to an output terminal of the power supply  5  such that the product quality is improved without using wires. In this way, the female plug  201  and the male plug  51  respectively provided for the LED light strip  2  and the power supply  5  are no longer needed. 
     Referring to  FIG.  24   , an output terminal of the printed circuit board of the power supply  5  may have soldering pads “a” provided with an amount of tin solder with a thickness sufficient to later form a solder joint. Correspondingly, the ends of the LED light strip  2  may have soldering pads “b”. The soldering pads “a” on the output terminal of the printed circuit board of the power supply  5  are soldered to the soldering pads “b” on the LED light strip  2  via the tin solder on the soldering pads “a”. The soldering pads “a” and the soldering pads “b” may be face to face during soldering such that the connection between the LED light strip  2  and the printed circuit board of the power supply  5  is the most firm. However, this kind of soldering typically includes that a thermo-compression head presses on the rear surface of the LED light strip  2  and heats the tine solder, i.e. the LED light strip  2  intervenes between the thermo-compression head and the tin solder, and therefore may easily cause reliability problems. Referring to  FIG.  30   , a through hole may be formed in each of the soldering pads “b” on the LED light strip  2  to allow the soldering pads “b” overlay the soldering pads “b” without face-to-face and the thermo-compression head directly presses tin solders on the soldering pads “a” on surface of the printed circuit board of the power supply  5  when the soldering pads “a” and the soldering pads “b” are vertically aligned. This is an easy way to accomplish in practice. 
     Referring again to  FIG.  24   , two ends of the LED light strip  2  detached from the inner surface of the lamp tube  1  are formed as freely extending portions  21 , while most of the LED light strip  2  is attached and secured to the inner surface of the lamp tube  1 . One of the freely extending portions  21  has the soldering pads “b” as mentioned above. Upon assembling of the LED tube lamp, the freely extending end portions  21  along with the soldered connection of the printed circuit board of the power supply  5  and the LED light strip  2  would be coiled, curled up or deformed to be fittingly accommodated inside the lamp tube  1 . When the bendable circuit sheet of the LED light strip  2  includes in sequence the first wiring layer  2   a , the dielectric layer  2   b , and the second wiring layer  2   c  as shown in  FIG.  48   , the freely extending end portions  21  can be used to accomplish the connection between the first wiring layer  2   a  and the second wiring layer  2   c  and arrange the circuit layout of the power supply  5 . 
     In this embodiment, during the connection of the LED light strip  2  and the power supply  5 , the soldering pads “b” and the soldering pads “a” and the LED light sources  202  are on surfaces facing toward the same direction and the soldering pads “b” on the LED light strip  2  are each formed with a through hole “e” as shown in  FIG.  30    such that the soldering pads “b” and the soldering pads “a” communicate with each other via the through holes “e”. When the freely extending end portions  21  are deformed due to contraction or curling up, the soldered connection of the printed circuit board of the power supply  5  and the LED light strip  2  exerts a lateral tension on the power supply  5 . Furthermore, the soldered connection of the printed circuit board of the power supply  5  and the LED light strip  2  also exerts a downward tension on the power supply  5  when compared with the situation where the soldering pads “a” of the power supply  5  and the soldering pads “b” of the LED light strip  2  are face to face. This downward tension on the power supply  5  comes from the tin solders inside the through holes “e” and forms a stronger and more secure electrical connection between the LED light strip  2  and the power supply  5 . 
     Referring to  FIG.  25   , in one embodiment, the soldering pads “b” of the LED light strip  2  are two separate pads to electrically connect the positive and negative electrodes of the bendable circuit sheet of the LED light strip  2 , respectively. The size of the soldering pads “b” may be, for example, about 3.5×2 mm 2 . The printed circuit board of the power supply  5  is correspondingly provided with soldering pads “a” having reserved tin solders, and the height of the tin solders suitable for subsequent automatic soldering bonding process is generally, for example, about 0.1 to 0.7 mm, in some preferable embodiments about 0.3 to about 0.5 mm, and in some even more preferable embodiments about 0.4 mm. An electrically insulating through hole “c” may be formed between the two soldering pads “b” to isolate and prevent the two soldering pads from electrically short during soldering. Furthermore, an extra positioning opening “d” may also be provided behind the electrically insulating through hole “c” to allow an automatic soldering machine to quickly recognize the position of the soldering pads “b”. 
     For the sake of achieving scalability and compatibility, the amount of the soldering pads “b” on each end of the LED light strip  2  may be more than one such as two, three, four, or more than four. When there is only one soldering pad “b” provided at each end of the LED light strip  2 , the two ends of the LED light strip  2  are electrically connected to the power supply  5  to form a loop, and various electrical components can be used. For example, a capacitance may be replaced by an inductance to perform current regulation. Referring to  FIG.  26  to  28   , when each end of the LED light strip  2  has three soldering pads, the third soldering pad can be grounded; when each end of the LED light strip  2  has four soldering pads, the fourth soldering pad can be used as a signal input terminal. Correspondingly, in some embodiments, the power supply  5  should have the same amount of soldering pads “a” as that of the soldering pads “b” on the LED light strip  2 . In some embodiments, as long as electrical short between the soldering pads “b” can be prevented, the soldering pads “b” should be arranged according to the dimension of the actual area for disposition, for example, three soldering pads can be arranged in a row or two rows. In other embodiments, the amount of the soldering pads “b” on the bendable circuit sheet of the LED light strip  2  may be reduced by rearranging the circuits on the bendable circuit sheet of the LED light strip  2 . The lesser the amount of the soldering pads, the easier the fabrication process becomes. On the other hand, a greater number of soldering pads may improve and secure the electrical connection between the LED light strip  2  and the output terminal of the power supply  5 . 
     Referring to  FIG.  30   , in another embodiment, the soldering pads “b” each is formed with a through hole “e” having a diameter generally of about 1 to 2 mm, in some preferred embodiments of about 1.2 to 1.8 mm, and in yet further preferred embodiments of about 1.5 mm. The through hole “e” communicates the soldering pad “a” with the soldering pad “b” so that the tin solder on the soldering pads “a” passes through the through holes “e” and finally reach the soldering pads “b”. A smaller through hole “e” would make it difficult for the tin solder to pass. The tin solder accumulates around the through holes “e” upon exiting the through holes “e” and condense to form a solder ball “g” with a larger diameter than that of the through holes “e” upon condensing. Such a solder ball “g” functions as a rivet to further increase the stability of the electrical connection between the soldering pads “a” on the power supply  5  and the soldering pads “b” on the LED light strip  2 . 
     Referring to  FIGS.  31  to  32   , in other embodiments, when a distance from the through hole “e” to the side edge of the LED light strip  2  is less than 1 mm, the tin solder may pass through the through hole “e” to accumulate on the periphery of the through hole “e”, and extra tin solder may spill over the soldering pads “b” to reflow along the side edge of the LED light strip  2  and join the tin solder on the soldering pads “a” of the power supply  5 . The tin solder then condenses to form a structure like a rivet to firmly secure the LED light strip  2  onto the printed circuit board of the power supply  5  such that reliable electric connection is achieved. Referring to  FIGS.  33  and  34   , in another embodiment, the through hole “e” can be replaced by a notch “f” formed at the side edge of the soldering pads “b” for the tin solder to easily pass through the notch “f” and accumulate on the periphery of the notch “f” and to form a solder ball with a larger diameter than that of the notch “e” upon condensing. Such a solder ball may be formed like a C-shape rivet to enhance the secure capability of the electrically connecting structure. 
     The abovementioned through hole “e” or notch “f” might be formed in advance of soldering or formed by direct punching with a thermo-compression head, as shown in  FIG.  40   , during soldering. The portion of the thermo-compression head for touching the tin solder may be flat, concave, or convex, or any combination thereof. The portion of the thermo-compression head for restraining the object to be soldered such as the LED light strip  2  may be strip-like or grid-like. The portion of the thermo-compression head for touching the tin solder does not completely cover the through hole “e” or the notch “f” to make sure that the tin solder is able to pass through the through hole “e” or the notch “f”. The portion of the thermo-compression head being concave may function as a room to receive the solder ball. 
     Referring to  FIG.  40   , a thermo-compression head  41  used for bonding the soldering pads “a” on the power supply  5  and the soldering pads “b” on the light strip  2  is mainly composed of four sections: a bonding plane  411 , a plurality of concave guiding tanks  412 , a plurality of concave molding tanks  413 , and a restraining plane  414 . The bonding plane  411  is a portion actually touching, pressing and heating the tin solder to perform soldering bonding. The bonding plane  411  may be flat, concave, convex or any combination thereof. The concave guiding tanks  412  are formed on the bonding plane  411  and opened near an edge of the bonding plane  411  to guide the heated and melted tin solder to flow into the through holes or notches formed on the soldering pads. For example, the guiding tanks  412  may function to guide and stop the melted tin solders. The concave molding tanks  413  are positioned beside the guiding tanks  412  and have a concave portion more depressed than that of the guiding tanks  412  such that the concave molding tanks  413  each form a housing to receive the solder ball. The restraining plane  414  is a portion next to the bonding plane  411  and formed with the concave molding tanks  413 . The restraining plane  414  is lower than the bonding plane  411  such that the restraining plane  414  firmly presses the LED light strip  2  on the printed circuit board of the power supply  5  while the bonding plane  411  presses against the soldering pads “b” during the soldering bonding. The restraining plane  414  may be strip-like or grid-like on surface. The difference of height of the bonding plane  411  and the restraining plane  414  is the thickness of the LED light strip  2 . 
     Referring to  FIGS.  41 ,  25 , and  40   , soldering pads corresponding to the soldering pads of the LED light strip are formed on the printed circuit board of the power supply  5  and tin solder is reserved on the soldering pads on the printed circuit board of the power supply  5  for subsequent soldering bonding performed by an automatic soldering bonding machine. The tin solder in some embodiments has a thickness of about 0.3 mm to about 0.5 mm such that the LED light strip  2  can be firmly soldered to the printed circuit board of the power supply  5 . As shown in  FIG.  41   , in case of having height difference between two tin solders respectively reserved on two soldering pads on the printed circuit board of the power supply  5 , the higher one will be touched first and melted by the thermo-compression head  41  while the other one will be touched and start to melt until the higher one is melted to a height the same as the height of the other one. This usually incurs unsecured soldering bonding for the reserved tin solder with smaller height, and therefore affects the electrical connection between the LED light strip  2  and the printed circuit board of the power supply  5 . To alleviate this problem, in one embodiment, the present invention applies the kinetic equilibrium principal and installs a linkage mechanism on the thermo-compression head  41  to allow rotation of the thermo-compression head  41  during a soldering bonding such that the thermo-compression head  41  starts to heat and melt the two reserved tin solders only when the thermo-compression head  41  detects that the pressure on the two reserved tin solders are the same. 
     In the abovementioned embodiment, the thermo-compression head  41  is rotatable while the LED light strip  2  and the printed circuit board of the power supply  5  remain unmoved. Referring to  FIG.  42   , in another embodiment, the thermo-compression head  41  is unmoved while the LED light strip is allowed to rotate. In this embodiment, the LED light strip  2  and the printed circuit board of the power supply  5  are loaded on a soldering vehicle  60  including a rotary platform  61 , a vehicle holder  62 , a rotating shaft  63 , and two elastic members  64 . The rotary platform  61  functions to carry the LED light strip  2  and the printed circuit board of the power supply  5 . The rotary platform  61  is movably mounted to the vehicle holder  62  via the rotating shaft  63  so that the rotary platform  61  is able to rotate with respect to the vehicle holder  62  while the vehicle holder  62  bears and holds the rotary platform  61 . The two elastic members  64  are disposed on two sides of the rotating shaft  63 , respectively, such that the rotary platform  61  in connection with the rotating shaft  63  always remains at the horizontal level when the rotary platform  61  is not loaded. In this embodiment, the elastic members  64  are springs for example, and the ends thereof are disposed corresponding to two sides of the rotating shaft  63  so as to function as two pivots on the vehicle holder  62 . As shown in  FIG.  42   , when two tin solders reserved on the LED light strip  2  pressed by the thermo-compression head  41  are not at the same height level, the rotary platform  61  carrying the LED light strip  2  and the printed circuit board of the power supply  5  will be driven by the rotating shaft  63  to rotate until the thermo-compression head  41  detects the same pressure on the two reserved tin solders, and then starts a soldering bonding. Referring to  FIG.  43   , when the rotary platform  61  rotates, the elastic members  64  at two sides of the rotating shaft  63  are compressed or pulled; and the driving force of the rotating shaft  63  releases and the rotary platform  61  returns to the original height level by the resilience of the elastic members  64  when the soldering bonding is completed. 
     In other embodiments, the rotary platform  61  may be designed to have mechanisms without using the rotating shaft  63  and the elastic members  64 . For example, the rotary platform  61  may be designed to have driving motors and active rotary mechanisms, and therefore the vehicle holder  62  is saved. Accordingly, other embodiments utilizing the kinetic equilibrium principle to drive the LED light strip  2  and the printed circuit board of the power supply  5  to move in order to complete the soldering bonding process are within the spirit of the present invention. 
     Referring to  FIGS.  35  and  36   , in another embodiment, the LED light strip  2  and the power supply  5  may be connected by utilizing a circuit board assembly  25  instead of soldering bonding. The circuit board assembly  25  has a long circuit sheet  251  and a short circuit board  253  that are adhered to each other with the short circuit board  253  being adjacent to the side edge of the long circuit sheet  251 . The short circuit board  253  may be provided with power supply module  250  to form the power supply  5 . The short circuit board  253  is stiffer or more rigid than the long circuit sheet  251  to be able to support the power supply module  250 . 
     The long circuit sheet  251  may be the bendable circuit sheet of the LED light strip including a wiring layer  2   a  as shown in  FIG.  23   . The wiring layer  2   a  of the long circuit sheet  251  and the power supply module  250  may be electrically connected in various manners depending on the application desired. As shown in  FIG.  35   , the power supply module  250  and the long circuit sheet  251  having the wiring layer  2   a  on a surface are on the same side of the short circuit board  253  such that the power supply module  250  is directly connected to the long circuit sheet  251 . As shown in  FIG.  36   , alternatively, the power supply module  250  and the long circuit sheet  251  including the wiring layer  2   a  on surface are on opposite sides of the short circuit board  253  such that the power supply module  250  is directly connected to the short circuit board  253  and indirectly connected to the wiring layer  2   a  of the LED light strip  2  by way of the short circuit board  253 . 
     As shown in  FIG.  35   , in one embodiment, the long circuit sheet  251  and the short circuit board  253  are adhered together first, and the power supply module  250  is subsequently mounted on the wiring layer  2   a  of the long circuit sheet  251  serving as the LED light strip  2 . The long circuit sheet  251  of the LED light strip  2  herein is not limited to include only one wiring layer  2   a  and may further include another wiring layer such as the wiring layer  2   c  shown in  FIG.  48   . The light sources  202  are disposed on the wiring layer  2   a  of the LED light strip  2  and electrically connected to the power supply  5  by way of the wiring layer  2   a . As shown in  FIG.  36   , in another embodiment, the long circuit sheet  251  of the LED light strip  2  may include a wiring layer  2   a  and a dielectric layer  2   b . The dielectric layer  2   b  may be adhered to the short circuit board  253  first and the wiring layer  2   a  is subsequently adhered to the dielectric layer  2   b  and extends to the short circuit board  253 . All these embodiments are within the scope of applying the circuit board assembly concept of the present invention. 
     In the above-mentioned embodiments, the short circuit board  253  may have a length generally of about 15 mm to about 40 mm and in some preferable embodiments about 19 mm to about 36 mm, while the long circuit sheet  251  may have a length generally of about 800 mm to about 2800 mm and in some embodiments of about 1200 mm to about 2400 mm. A ratio of the length of the short circuit board  253  to the length of the long circuit sheet  251  ranges from, for example, about 1:20 to about 1:200. 
     When the ends of the LED light strip  2  are not fixed on the inner surface of the lamp tube  1 , the connection between the LED light strip  2  and the power supply  5  via soldering bonding could not firmly support the power supply  5 , and it may be necessary to dispose the power supply  5  inside the end cap  3 . For example, a longer end cap to have enough space for receiving the power supply  5  would be needed. However, this will reduce the length of the lamp tube under the prerequisite that the total length of the LED tube lamp is fixed according to the product standard and may therefore decrease the effective illuminating areas. 
     Referring to  FIG.  39   , in one embodiment, a hard circuit board  22  made of aluminum is used instead of the bendable circuit sheet, such that the ends or terminals of the hard circuit board  22  can be mounted at ends of the lamp tube  1 , and the power supply  5  is solder bonded to one of the ends or terminals of the hard circuit board  22  in a manner such that the printed circuit board of the power supply  5  is not parallel but may be perpendicular to the hard circuit board  22  to save space in the longitudinal direction used for the end cap. This solder bonding technique may be more convenient to accomplish and the effective illuminating areas of the LED tube lamp could also remain. Moreover, a conductive lead  53  for electrical connection with the end cap  3  could be formed directly on the power supply  5  without soldering other metal wires between the power supply  5  and the hollow conductive pin  301  as shown in  FIG.  3   , and which facilitates the manufacturing of the LED tube lamp. 
     Next, examples of the circuit design and using of the power supply module  250  are described as follows. 
       FIG.  49 A  is a block diagram of a power supply module  250  in an LED tube lamp according to an embodiment of the present invention. Referring to  FIG.  49 A , an AC power supply  508  is used to supply an AC supply signal, and may be an AC powerline with a voltage rating, for example, in 100-277 volts and a frequency rating, for example, of 50 or 60 Hz. A lamp driving circuit  505  receives and then converts the AC supply signal into an AC driving signal as an external driving signal. Lamp driving circuit  505  may be for example an electronic ballast used to convert the AC powerline into a high-frequency high-voltage AC driving signal. Common types of electronic ballast include instant-start ballast, program-start or rapid-start ballast, etc., which may all be applicable to the LED tube lamp of the present invention. The voltage of the AC driving signal is likely higher than 300 volts and is in some embodiments in the range of about 400-700 volts. The frequency of the AC driving signal is likely higher than 10 k Hz and is in some embodiments in the range of about 20 k-50 k Hz. The LED tube lamp  500  receives an external driving signal and is thus driven to emit light. In one embodiment, the external driving signal comprises the AC driving signal from lamp driving circuit  505 . In one embodiment, LED tube lamp  500  is in a driving environment in which it is power-supplied at its one end cap having two conductive pins  501  and  502 , which are coupled to lamp driving circuit  505  to receive the AC driving signal. The two conductive pins  501  and  502  may be electrically connected to, either directly or indirectly, the lamp driving circuit  505 . 
     It is worth noting that lamp driving circuit  505  may be omitted and is therefore depicted by a dotted line. In one embodiment, if lamp driving circuit  505  is omitted, AC power supply  508  is directly connected to pins  501  and  502 , which then receive the AC supply signal as an external driving signal. 
     In addition to the above use with a single-end power supply, LED tube lamp  500  may instead be used with a dual-end power supply to one pin at each of the two ends of an LED lamp tube.  FIG.  49 B  is a block diagram of a power supply module  250  in an LED tube lamp according to one embodiment of the present invention. Referring to  FIG.  49 B , compared to that shown in  FIG.  49 A , pins  501  and  502  are respectively disposed at the two opposite end caps of LED tube lamp  500 , forming a single pin at each end of LED tube lamp  500 , with other components and their functions being the same as those in  FIG.  49 A . 
       FIG.  49 C  is a block diagram of an LED lamp according to one embodiment of the present invention. Referring to  FIG.  49 C , the power supply module of the LED lamp summarily includes a rectifying circuit  510 , a filtering circuit  520 , and an LED driving module  530 . Rectifying circuit  510  is coupled to pins  501  and  502  to receive and then rectify an external driving signal, so as to output a rectified signal at output terminals  511  and  512 . The external driving signal may be the AC driving signal or the AC supply signal described with reference to  FIGS.  49 A and  49 B , or may even be a DC signal, which embodiments do not alter the LED lamp of the present invention. Filtering circuit  520  is coupled to the first rectifying circuit for filtering the rectified signal to produce a filtered signal, as recited in the claims. For instance, filtering circuit  520  is coupled to terminals  511  and  512  to receive and then filter the rectified signal, so as to output a filtered signal at output terminals  521  and  522 . LED driving module  530  is coupled to filtering circuit  520 , to receive the filtered signal for emitting light. For instance, LED driving module  530  may be a circuit coupled to terminals  521  and  522  to receive the filtered signal and thereby to drive an LED unit (not shown) in LED driving module  530  to emit light. Details of these operations are described in below descriptions of certain embodiments. 
     It is worth noting that although there are two output terminals  511  and  512  and two output terminals  521  and  522  in embodiments of these Figs., in practice the number of ports or terminals for coupling between rectifying circuit  510 , filtering circuit  520 , and LED driving module  530  may be one or more depending on the needs of signal transmission between the circuits or devices. 
     In addition, the power supply module of the LED lamp described in  FIG.  49 C , and embodiments of the power supply module of an LED lamp described below, may each be used in the LED tube lamp  500  in  FIGS.  49 A and  49 B , and may instead be used in any other type of LED lighting structure having two conductive pins used to conduct power, such as LED light bulbs, personal area lights (PAL), plug-in LED lamps with different types of bases (such as types of PL-S, PL-D, PL-T, PL-L, etc.), etc. 
       FIG.  49 D  is a block diagram of a power supply module  250  in an LED tube lamp according to an embodiment of the present invention. Referring to  FIG.  49 D , an AC power supply  508  is used to supply an AC supply signal. A lamp driving circuit  505  receives and then converts the AC supply signal into an AC driving signal. An LED tube lamp  500  receives an AC driving signal from lamp driving circuit  505  and is thus driven to emit light. In this embodiment, LED tube lamp  500  is power-supplied at its both end caps respectively having two pins  501  and  502  and two pins  503  and  504 , which are coupled to lamp driving circuit  505  to concurrently receive the AC driving signal to drive an LED unit (not shown) in LED tube lamp  500  to emit light. AC power supply  508  may be e.g. the AC powerline, and lamp driving circuit  505  may be a stabilizer or an electronic ballast. 
       FIG.  49 E  is a block diagram of an LED lamp according to an embodiment of the present invention. Referring to  FIG.  49 E , the power supply module of the LED lamp summarily includes a rectifying circuit  510 , a filtering circuit  520 , an LED driving module  530 , and a filtering circuit  540 . Rectifying circuit  510  is coupled to pins  501  and  502  to receive and then rectify an external driving signal conducted by pins  501  and  502 . Rectifying circuit  540  is coupled to pins  503  and  504  to receive and then rectify an external driving signal conducted by pins  503  and  504 . Therefore, the power supply module of the LED lamp may include two rectifying circuits  510  and  540  configured to output a rectified signal at output terminals  511  and  512 . Filtering circuit  520  is coupled to terminals  511  and  512  to receive and then filter the rectified signal, so as to output a filtered signal at output terminals  521  and  522 . LED driving module  530  is coupled to terminals  521  and  522  to receive the filtered signal and thereby to drive an LED unit (not shown) in LED driving module  530  to emit light. 
     The power supply module of the LED lamp in this embodiment of  FIG.  49 E  may be used in LED tube lamp  500  with a dual-end power supply in  FIG.  49 D . It is worth noting that since the power supply module of the LED lamp comprises rectifying circuits  510  and  540 , the power supply module of the LED lamp may be used in LED tube lamp  500  with a single-end power supply in  FIGS.  49 A and  49 B , to receive an external driving signal (such as the AC supply signal or the AC driving signal described above). The power supply module of an LED lamp in this embodiment and other embodiments herein may also be used with a DC driving signal. 
       FIG.  50 A  is a schematic diagram of a rectifying circuit according to an embodiment of the present invention. Referring to  FIG.  50 A , rectifying circuit  610  includes rectifying diodes  611 ,  612 ,  613 , and  614 , configured to full-wave rectify a received signal. Diode  611  has an anode connected to output terminal  512 , and a cathode connected to pin  502 . Diode  612  has an anode connected to output terminal  512 , and a cathode connected to pin  501 . Diode  613  has an anode connected to pin  502 , and a cathode connected to output terminal  511 . Diode  614  has an anode connected to pin  501 , and a cathode connected to output terminal  511 . 
     When pins  501  and  502  receive an AC signal, rectifying circuit  610  operates as follows. During the connected AC signal&#39;s positive half cycle, the AC signal is input through pin  501 , diode  614 , and output terminal  511  in sequence, and later output through output terminal  512 , diode  611 , and pin  502  in sequence. During the connected AC signal&#39;s negative half cycle, the AC signal is input through pin  502 , diode  613 , and output terminal  511  in sequence, and later output through output terminal  512 , diode  612 , and pin  501  in sequence. Therefore, during the connected AC signal&#39;s full cycle, the positive pole of the rectified signal produced by rectifying circuit  610  remains at output terminal  511 , and the negative pole of the rectified signal remains at output terminal  512 . Accordingly, the rectified signal produced or output by rectifying circuit  610  is a full-wave rectified signal. 
     When pins  501  and  502  are coupled to a DC power supply to receive a DC signal, rectifying circuit  610  operates as follows. When pin  501  is coupled to the anode of the DC supply and pin  502  to the cathode of the DC supply, the DC signal is input through pin  501 , diode  614 , and output terminal  511  in sequence, and later output through output terminal  512 , diode  611 , and pin  502  in sequence. When pin  501  is coupled to the cathode of the DC supply and pin  502  to the anode of the DC supply, the DC signal is input through pin  502 , diode  613 , and output terminal  511  in sequence, and later output through output terminal  512 , diode  612 , and pin  501  in sequence. Therefore, no matter what the electrical polarity of the DC signal is between pins  501  and  502 , the positive pole of the rectified signal produced by rectifying circuit  610  remains at output terminal  511 , and the negative pole of the rectified signal remains at output terminal  512 . 
     Therefore, rectifying circuit  610  in this embodiment can output or produce a proper rectified signal regardless of whether the received input signal is an AC or DC signal. 
       FIG.  50 B  is a schematic diagram of a rectifying circuit according to an embodiment of the present invention. Referring to  FIG.  50 B , rectifying circuit  710  includes rectifying diodes  711  and  712 , configured to half-wave rectify a received signal. Diode  711  has an anode connected to pin  502 , and a cathode connected to output terminal  511 . Diode  712  has an anode connected to output terminal  511 , and a cathode connected to pin  501 . Output terminal  512  may be omitted or grounded depending on actual applications. 
     Next, exemplary operation(s) of rectifying circuit  710  is described as follows. 
     In one embodiment, during a received AC signal&#39;s positive half cycle, the electrical potential at pin  501  is higher than that at pin  502 , so diodes  711  and  712  are both in a cutoff state as being reverse-biased, making rectifying circuit  710  not outputting a rectified signal. During a received AC signal&#39;s negative half cycle, the electrical potential at pin  501  is lower than that at pin  502 , so diodes  711  and  712  are both in a conducting state as being forward-biased, allowing the AC signal to be input through diode  711  and output terminal  511 , and later output through output terminal  512 , a ground terminal, or another end of the LED tube lamp not directly connected to rectifying circuit  710 . Accordingly, the rectified signal produced or output by rectifying circuit  710  is a half-wave rectified signal. 
       FIG.  50 C  is a schematic diagram of a rectifying circuit according to an embodiment of the present invention. Referring to  FIG.  50 C , rectifying circuit  810  includes a rectifying unit  815  and a terminal adapter circuit  541 . In this embodiment, rectifying unit  815  comprises a half-wave rectifier circuit including diodes  811  and  812  and configured to half-wave rectify. Diode  811  has an anode connected to an output terminal  512 , and a cathode connected to a half-wave node  819 . Diode  812  has an anode connected to half-wave node  819 , and a cathode connected to an output terminal  511 . Terminal adapter circuit  541  is coupled to half-wave node  819  and pins  501  and  502 , to transmit a signal received at pin  501  and/or pin  502  to half-wave node  819 . By means of the terminal adapting function of terminal adapter circuit  541 , rectifying circuit  810  allows of two input terminals (connected to pins  501  and  502 ) and two output terminals  511  and  512 . 
     Next, in certain embodiments, rectifying circuit  810  operates as follows. 
     During a received AC signal&#39;s positive half cycle, the AC signal may be input through pin  501  or  502 , terminal adapter circuit  541 , half-wave node  819 , diode  812 , and output terminal  511  in sequence, and later output through another end or circuit of the LED tube lamp. During a received AC signal&#39;s negative half cycle, the AC signal may be input through another end or circuit of the LED tube lamp, and later output through output terminal  512 , diode  811 , half-wave node  819 , terminal adapter circuit  541 , and pin  501  or  502  in sequence. 
     It&#39;s worth noting that terminal adapter circuit  541  may comprise a resistor, a capacitor, an inductor, or any combination thereof, for performing functions of voltage/current regulation or limiting, types of protection, current/voltage regulation, etc. Descriptions of these functions are presented below. 
     In practice, rectifying unit  815  and terminal adapter circuit  541  may be interchanged in position (as shown in  FIG.  50 D ), without altering the function of half-wave rectification.  FIG.  50 D  is a schematic diagram of a rectifying circuit according to an embodiment of the present invention. Referring to  FIG.  50 D , diode  811  has an anode connected to pin  502  and diode  812  has a cathode connected to pin  501 . A cathode of diode  811  and an anode of diode  812  are connected to half-wave node  819 . Terminal adapter circuit  541  is coupled to half-wave node  819  and output terminals  511  and  512 . During a received AC signal&#39;s positive half cycle, the AC signal may be input through another end or circuit of the LED tube lamp, and later output through output terminal  512  or  512 , terminal adapter circuit  541 , half-wave node  819 , diode  812 , and pin  501  in sequence. During a received AC signal&#39;s negative half cycle, the AC signal may be input through pin  502 , diode  811 , half-wave node  819 , terminal adapter circuit  541 , and output node  511  or  512  in sequence, and later output through another end or circuit of the LED tube lamp. 
     It is worth noting that terminal adapter circuit  541  in embodiments shown in  FIGS.  50 C and  50 D  may be omitted and is therefore depicted by a dotted line. If terminal adapter circuit  541  of  FIG.  50 C  is omitted, pins  501  and  502  will be coupled to half-wave node  819 . If terminal adapter circuit  541  of  FIG.  50 D  is omitted, output terminals  511  and  512  will be coupled to half-wave node  819 . 
     Rectifying circuit  510  as shown and explained in  FIGS.  50 A-D  can constitute or be the rectifying circuit  540  shown in  FIG.  49 E , as having pins  503  and  504  for conducting instead of pins  501  and  502 . 
     Next, an explanation follows as to choosing embodiments and their combinations of rectifying circuits  510  and  540 , with reference to  FIGS.  49 C and  49 E . 
     Rectifying circuit  510  in embodiments shown in  FIG.  49 C  may comprise the rectifying circuit  610  in  FIG.  50 A . 
     Rectifying circuits  510  and  540  in embodiments shown in  FIG.  49 E  may each comprise any one of the rectifying circuits in  FIGS.  50 A-D , and terminal adapter circuit  541  in  FIGS.  50 C-D  may be omitted without altering the rectification function needed in an LED tube lamp. When rectifying circuits  510  and  540  each comprise a half-wave rectifier circuit described in  FIGS.  50 B-D , during a received AC signal&#39;s positive or negative half cycle, the AC signal may be input from one of rectifying circuits  510  and  540 , and later output from the other rectifying circuit  510  or  540 . Further, when rectifying circuits  510  and  540  each comprise the rectifying circuit described in  FIG.  50 C or  50 D , or when they comprise the rectifying circuits in  FIGS.  50 C and  50 D  respectively, only one terminal adapter circuit  541  may be needed for functions of voltage/current regulation or limiting, types of protection, current/voltage regulation, etc. within rectifying circuits  510  and  540 , omitting another terminal adapter circuit  541  within rectifying circuit  510  or  540 . 
       FIG.  51 A  is a schematic diagram of the terminal adapter circuit according to an embodiment of the present invention. Referring to  FIG.  51 A , terminal adapter circuit  641  comprises a capacitor  642  having an end connected to pins  501  and  502 , and another end connected to half-wave node  819 . Capacitor  642  has an equivalent impedance to an AC signal, which impedance increases as the frequency of the AC signal decreases, and decreases as the frequency increases. Therefore, capacitor  642  in terminal adapter circuit  641  in this embodiment works as a high-pass filter. Further, terminal adapter circuit  641  is connected in series to an LED unit in the LED tube lamp, producing an equivalent impedance of terminal adapter circuit  641  to perform a current/voltage limiting function on the LED unit, thereby preventing damaging of the LED unit by an excessive voltage across and/or current in the LED unit. In addition, choosing the value of capacitor  642  according to the frequency of the AC signal can further enhance voltage/current regulation. 
     It&#39;s worth noting that terminal adapter circuit  641  may further include a capacitor  645  and/or capacitor  646 . Capacitor  645  has an end connected to half-wave node  819 , and another end connected to pin  503 . Capacitor  646  has an end connected to half-wave node  819 , and another end connected to pin  504 . For example, half-wave node  819  may be a common connective node between capacitors  645  and  646 . And capacitor  642  acting as a current regulating capacitor is coupled to the common connective node and pins  501  and  502 . In such a structure, series-connected capacitors  642  and  645  exist between one of pins  501  and  502  and pin  503 , and/or series-connected capacitors  642  and  646  exist between one of pins  501  and  502  and pin  504 . Through equivalent impedances of series-connected capacitors, voltages from the AC signal are divided. Referring to  FIGS.  49 E and  51 A , according to ratios between equivalent impedances of the series-connected capacitors, the voltages respectively across capacitor  642  in rectifying circuit  510 , filtering circuit  520 , and LED driving module  530  can be controlled, making the current flowing through an LED module in LED driving module  530  being limited within a current rating, and then protecting/preventing filtering circuit  520  and LED driving module  530  from being damaged by excessive voltages. 
       FIG.  51 B  is a schematic diagram of the terminal adapter circuit according to an embodiment of the present invention. Referring to  FIG.  51 B , terminal adapter circuit  741  comprises capacitors  743  and  744 . Capacitor  743  has an end connected to pin  501 , and another end connected to half-wave node  819 . Capacitor  744  has an end connected to pin  502 , and another end connected to half-wave node  819 . Compared to terminal adapter circuit  641  in  FIG.  51 A , terminal adapter circuit  741  has capacitors  743  and  744  in place of capacitor  642 . Capacitance values of capacitors  743  and  744  may be the same as each other or may differ from each other depending on the magnitudes of signals to be received at pins  501  and  502 . 
     Similarly, terminal adapter circuit  741  may further comprise a capacitor  745  and/or a capacitor  746 , respectively connected to pins  503  and  504 . Thus, each of pins  501  and  502  and each of pins  503  and  504  may be connected in series to a capacitor, to achieve the functions of voltage division and other protections. 
       FIG.  51 C  is a schematic diagram of the terminal adapter circuit according to an embodiment of the present invention. Referring to  FIG.  51 C , terminal adapter circuit  841  comprises capacitors  842 ,  843 , and  844 . Capacitors  842  and  843  are connected in series between pin  501  and half-wave node  819 . Capacitors  842  and  844  are connected in series between pin  502  and half-wave node  819 . In such a circuit structure, if any one of capacitors  842 ,  843 , and  844  is shorted, there is still at least one capacitor (of the other two capacitors) between pin  501  and half-wave node  819  and between pin  502  and half-wave node  819 , which performs a current-limiting function. Therefore, in the event that a user accidentally gets an electric shock, this circuit structure will prevent an excessive current flowing through and then seriously hurting the body of the user. 
     Similarly, terminal adapter circuit  841  may further comprise a capacitor  845  and/or a capacitor  846 , respectively connected to pins  503  and  504 . Thus, each of pins  501  and  502  and each of pins  503  and  504  may be connected in series to a capacitor, to achieve the functions of voltage division and other protections. 
       FIG.  51 D  is a schematic diagram of the terminal adapter circuit according to an embodiment of the present invention. Referring to  FIG.  51 D , terminal adapter circuit  941  comprises fuses  947  and  948 . Fuse  947  has an end connected to pin  501 , and another end connected to half-wave node  819 . Fuse  948  has an end connected to pin  502 , and another end connected to half-wave node  819 . With the fuses  947  and  948 , when the current through each of pins  501  and  502  exceeds a current rating of a corresponding connected fuse  947  or  948 , the corresponding fuse  947  or  948  will accordingly melt and then break the circuit to achieve overcurrent protection. 
     Each of the embodiments of the terminal adapter circuits as in rectifying circuits  510  and  810  coupled to pins  501  and  502  and shown and explained above can be used or included in the rectifying circuit  540  shown in  FIG.  49 E , as when conductive pins  503  and  504  and conductive pins  501  and  502  are interchanged in position. 
     Capacitance values of the capacitors in the embodiments of the terminal adapter circuits shown and described above are in some embodiments in the range, for example, of about 100 pF-100 nF. Also, a capacitor used in embodiments may be equivalently replaced by two or more capacitors connected in series or parallel. For example, each of capacitors  642  and  842  may be replaced by two series-connected capacitors, one having a capacitance value chosen from the range, for example of about 1.0 nF to about 2.5 nF and which may be in some embodiments preferably 1.5 nF, and the other having a capacitance value chosen from the range, for example of about 1.5 nF to about 3.0 nF, and which is in some embodiments about 2.2 nF. 
       FIG.  52 A  is a block diagram of the filtering circuit according to an embodiment of the present invention. Rectifying circuit  510  is shown in  FIG.  52 A  for illustrating its connection with other components, without intending filtering circuit  520  to include rectifying circuit  510 . Referring to  FIG.  52 A , filtering circuit  520  includes a filtering unit  523  coupled to rectifying output terminals  511  and  512  to receive, and to filter out ripples of, a rectified signal from rectifying circuit  510 , thereby outputting a filtered signal whose waveform is smoother than the rectified signal. Filtering circuit  520  may further comprise another filtering unit  524  coupled between a rectifying circuit and a pin, which are for example rectifying circuit  510  and pin  501 , rectifying circuit  510  and pin  502 , rectifying circuit  540  and pin  503 , or rectifying circuit  540  and pin  504 . Filtering unit  524  is for filtering of a specific frequency, in order to filter out a specific frequency component of an external driving signal. In this embodiment of  FIG.  52 A , filtering unit  524  is coupled between rectifying circuit  510  and pin  501 . Filtering circuit  520  may further comprise another filtering unit  525  coupled between one of pins  501  and  502  and a diode of rectifying circuit  510 , or between one of pins  503  and  504  and a diode of rectifying circuit  540 , for reducing or filtering out electromagnetic interference (EMI). In this embodiment, filtering unit  525  is coupled between pin  501  and a diode (not shown in  FIG.  52 A ) of rectifying circuit  510 . Since filtering units  524  and  525  may be present or omitted depending on actual circumstances of their uses, they are depicted by a dotted line in  FIG.  52 A . 
       FIG.  52 B  is a schematic diagram of the filtering unit according to an embodiment of the present invention. Referring to  FIG.  52 B , filtering unit  623  includes a capacitor  625  having an end coupled to output terminal  511  and a filtering output terminal  521  and another end coupled to output terminal  512  and a filtering output terminal  522 , and is configured to low-pass filter a rectified signal from output terminals  511  and  512 , so as to filter out high-frequency components of the rectified signal and thereby output a filtered signal at output terminals  521  and  522 . 
       FIG.  52 C  is a schematic diagram of the filtering unit according to an embodiment of the present invention. Referring to  FIG.  52 C , filtering unit  723  comprises a pi filter circuit including a capacitor  725 , an inductor  726 , and a capacitor  727 . As is well known, a pi filter circuit looks like the symbol π in its shape or structure. Capacitor  725  has an end connected to output terminal  511  and coupled to output terminal  521  through inductor  726 , and has another end connected to output terminals  512  and  522 . Inductor  726  is coupled between output terminals  511  and  521 . Capacitor  727  has an end connected to output terminal  521  and coupled to output terminal  511  through inductor  726 , and has another end connected to output terminals  512  and  522 . 
     As seen between output terminals  511  and  512  and output terminals  521  and  522 , filtering unit  723  compared to filtering unit  623  in  FIG.  52 B  additionally has inductor  726  and capacitor  727 , which are like capacitor  725  in performing low-pass filtering. Therefore, filtering unit  723  in this embodiment compared to filtering unit  623  in  FIG.  52 B  has a better ability to filter out high-frequency components to output a filtered signal with a smoother waveform. 
     Inductance values of inductor  726  in the embodiment described above are chosen in some embodiments in the range of about 10 nH to about 10 mH. And capacitance values of capacitors  625 ,  725 , and  727  in the embodiments described above are chosen in some embodiments in the range, for example, of about 100 pF to about 1 uF. 
       FIG.  52 D  is a schematic diagram of the filtering unit according to an embodiment of the present invention. Referring to  FIG.  52 D , filtering unit  824  includes a capacitor  825  and an inductor  828  connected in parallel. Capacitor  825  has an end coupled to pin  501 , and another end coupled to rectifying output terminal  511 , and is configured to high-pass filter an external driving signal input at pin  501 , so as to filter out low-frequency components of the external driving signal. Inductor  828  has an end coupled to pin  501  and another end coupled to rectifying output terminal  511 , and is configured to low-pass filter an external driving signal input at pin  501 , so as to filter out high-frequency components of the external driving signal. Therefore, the combination of capacitor  825  and inductor  828  works to present high impedance to an external driving signal at one or more specific frequencies. Thus, the parallel-connected capacitor and inductor work to present a peak equivalent impedance to the external driving signal at a specific frequency. 
     Through appropriately choosing a capacitance value of capacitor  825  and an inductance value of inductor  828 , a center frequency f on the high-impedance band may be set at a specific value given by 
               f   =     1     2   ⁢   π   ⁢     LC           ,         
where L denotes inductance of inductor  828  and C denotes capacitance of capacitor  825 . The center frequency is in some embodiments in the range of about 20˜30 kHz and may be preferably about 25 kHz. And an LED lamp with filtering unit  824  is able to be certified under safety standards, for a specific center frequency, as provided by Underwriters Laboratories (UL).
 
     It&#39;s worth noting that filtering unit  824  may further comprise a resistor  829 , coupled between pin  501  and filtering output terminal  511 . In  FIG.  52 D , resistor  829  is connected in series to the parallel-connected capacitor  825  and inductor  828 . For example, resistor  829  may be coupled between pin  501  and parallel-connected capacitor  825  and inductor  828 , or may be coupled between filtering output terminal  511  and parallel-connected capacitor  825  and inductor  828 . In this embodiment, resistor  829  is coupled between pin  501  and parallel-connected capacitor  825  and inductor  828 . Further, resistor  829  is configured for adjusting the quality factor (Q) of the LC circuit comprising capacitor  825  and inductor  828 , to better adapt filtering unit  824  to application environments with different quality factor requirements. Since resistor  829  is an optional component, it is depicted in a dotted line in  FIG.  52 D . 
     Capacitance values of capacitor  825  are in some embodiments in the range of about 10 nF-2 uF. Inductance values of inductor  828  are in some embodiments smaller than 2 mH and may be preferably smaller than 1 mH. Resistance values of resistor  829  are in some embodiments larger than 50 ohms, and in some embodiments preferably larger than 500 ohms. 
     Besides the filtering circuits shown and described in the above embodiments, traditional low-pass or band-pass filters can be used as the filtering unit in the filtering circuit in the present invention. 
       FIG.  52 E  is a schematic diagram of the filtering unit according to an embodiment of the present invention. Referring to  FIG.  52 E , in this embodiment filtering unit  925  is disposed in rectifying circuit  610  as shown in  FIG.  50 A , and is configured for reducing the EMI (Electromagnetic interference) caused by rectifying circuit  610  and/or other circuits. In this embodiment, filtering unit  925  includes an EMI-reducing capacitor coupled between pin  501  and the anode of rectifying diode  613 , and also between pin  502  and the anode of rectifying diode  614 , to reduce the EMI associated with the positive half cycle of the AC driving signal received at pins  501  and  502 . The EMI-reducing capacitor of filtering unit  925  is also coupled between pin  501  and the cathode of rectifying diode  611 , and between pin  502  and the cathode of rectifying diode  612 , to reduce the EMI associated with the negative half cycle of the AC driving signal received at pins  501  and  502 . In some embodiments, rectifying circuit  610  comprises a full-wave bridge rectifier circuit including four rectifying diodes  611 ,  612 ,  613 , and  614 . The full-wave bridge rectifier circuit has a first filtering node connecting an anode and a cathode respectively of two diodes  613  and  611  of the four rectifying diodes  611 ,  612 ,  613 , and  614 , and a second filtering node connecting an anode and a cathode respectively of the other two diodes  614  and  612  of the four rectifying diodes  611 ,  612 ,  613 , and  614 . And the EMI-reducing capacitor of the filtering unit  925  is coupled between the first filtering node and the second filtering node. 
     Similarly, with reference to  FIGS.  50 C, and  51 A- 51 C , any capacitor in each of the circuits in  FIGS.  51 A- 51 C  is coupled between pins  501  and  502  (or pins  503  and  504 ) and any diode in  FIG.  50 C , so any or each capacitor in  FIGS.  51 A- 51 C  can work as an EMI-reducing capacitor to achieve the function of reducing EMI. For example, rectifying circuit  510  in  FIGS.  49 C and  49 E  may comprise a half-wave rectifier circuit including two rectifying diodes and having a half-wave node connecting an anode and a cathode respectively of the two rectifying diodes, and any or each capacitor in  FIGS.  51 A- 51 C  may be coupled between the half-wave node and at least one of the first pin and the second pin. And rectifying circuit  540  in  FIG.  49 E  may comprise a half-wave rectifier circuit including two rectifying diodes and having a half-wave node connecting an anode and a cathode respectively of the two rectifying diodes, and any or each capacitor in  FIGS.  51 A- 51 C  may be coupled between the half-wave node and at least one of the third pin and the fourth pin. 
     It&#39;s worth noting that the EMI-reducing capacitor in the embodiment of  FIG.  52 E  may also act as capacitor  825  in filtering unit  824 , so that in combination with inductor  828  and the capacitor  825  performs the functions of reducing EMI and presenting high impedance to an external driving signal at specific frequencies. For example, when the rectifying circuit comprises a full-wave bridge rectifier circuit, capacitor  825  of filtering unit  824  may be coupled between the first filtering node and the second filtering node of the full-wave bridge rectifier circuit. When the rectifying circuit comprises a half-wave rectifier circuit, capacitor  825  of filtering unit  824  may be coupled between the half-wave node of the half-wave rectifier circuit and at least one of the first pin and the second pin. 
       FIG.  53 A  is a schematic diagram of an LED module according to an embodiment of the present invention. Referring to  FIG.  53 A , LED module  630  has an anode connected to the filtering output terminal  521 , has a cathode connected to the filtering output terminal  522 , and comprises at least one LED unit  632 . When two or more LED units are included, they are connected in parallel. The anode of each LED unit  632  is connected to the anode of LED module  630  and thus output terminal  521 , and the cathode of each LED unit  632  is connected to the cathode of LED module  630  and thus output terminal  522 . Each LED unit  632  includes at least one LED  631 . When multiple LEDs  631  are included in an LED unit  632 , they are connected in series, with the anode of the first LED  631  connected to the anode of this LED unit  632 , and the cathode of the first LED  631  connected to the next or second LED  631 . And the anode of the last LED  631  in this LED unit  632  is connected to the cathode of a previous LED  631 , with the cathode of the last LED  631  connected to the cathode of this LED unit  632 . 
     It&#39;s worth noting that LED module  630  may produce a current detection signal S 531  reflecting a magnitude of current through LED module  630  and used for controlling or detecting on the LED module  630 . 
       FIG.  53 B  is a schematic diagram of an LED module according to an embodiment of the present invention. Referring to  FIG.  53 B , LED module  630  has an anode connected to the filtering output terminal  521 , has a cathode connected to the filtering output terminal  522 , and comprises at least two LED units  732 , with the anode of each LED unit  732  connected to the anode of LED module  630 , and the cathode of each LED unit  732  connected to the cathode of LED module  630 . Each LED unit  732  includes at least two LEDs  731  connected in the same way as described in  FIG.  53 A . For example, the anode of the first LED  731  in an LED unit  732  is connected to the anode of this LED unit  732 , the cathode of the first LED  731  is connected to the anode of the next or second LED  731 , and the cathode of the last LED  731  is connected to the cathode of this LED unit  732 . Further, LED units  732  in an LED module  630  are connected to each other in this embodiment. All of the n-th LEDs  731  respectively of the LED units  732  are connected by every anode of every n-th LED  731  in the LED units  732 , and by every cathode of every n-th LED  731 , where n is a positive integer. In this way, the LEDs in LED module  630  in this embodiment are connected in the form of a mesh. 
     Compared to the embodiments of  FIGS.  54 A- 54 G , LED driving module  530  of the above embodiments includes LED module  630 , but does not include a driving circuit for the LED module  630 . 
     Similarly, LED module  630  in this embodiment may produce a current detection signal S 531  reflecting a magnitude of current through LED module  630  and used for controlling or detecting on the LED module  630 . 
     In actual practice, the number of LEDs  731  included by an LED unit  732  is in some embodiments in the range of 15-25, and preferably in the range of 18-22. 
       FIG.  53 C  is a plan view of a circuit layout of the LED module according to an embodiment of the present invention. Referring to  FIG.  53 C , in this embodiment LEDs  831  are connected in the same way as described in  FIG.  53 B , and three LED units are assumed in LED module  630  and described as follows for illustration. A positive conductive line  834  and a negative conductive line  835  are to receive a driving signal, for supplying power to the LEDs  831 . For example, positive conductive line  834  may be coupled to the filtering output terminal  521  of the filtering circuit  520  described above, and negative conductive line  835  coupled to the filtering output terminal  522  of the filtering circuit  520 , to receive a filtered signal. For the convenience of illustration, all three of the n-th LEDs  831  respectively of the three LED units are grouped as an LED set  833  in  FIG.  53 C . 
     Positive conductive line  834  connects the three first LEDs  831  respectively of the leftmost three LED units, at the anodes on the left sides of the three first LEDs  831  as shown in the leftmost LED set  833  of  FIG.  53 C . Negative conductive line  835  connects the three last LEDs  831  respectively of the leftmost three LED units, at the cathodes on the right sides of the three last LEDs  831  as shown in the rightmost LED set  833  of  FIG.  53 C . And of the three LED units, the cathodes of the three first LEDs  831 , the anodes of the three last LEDs  831 , and the anodes and cathodes of all the remaining LEDs  831  are connected by conductive lines or parts  839 . 
     For example, the anodes of the three LEDs  831  in the leftmost LED set  833  may be connected together by positive conductive line  834 , and their cathodes may be connected together by a leftmost conductive part  839 . The anodes of the three LEDs  831  in the second leftmost LED set  833  are also connected together by the leftmost conductive part  839 , whereas their cathodes are connected together by a second leftmost conductive part  839 . Since the cathodes of the three LEDs  831  in the leftmost LED set  833  and the anodes of the three LEDs  831  in the second leftmost LED set  833  are connected together by the same leftmost conductive part  839 , in each of the three LED units the cathode of the first LED  831  is connected to the anode of the next or second LED  831 , with the remaining LEDs  831  also being connected in the same way. Accordingly, all the LEDs  831  of the three LED units are connected to form the mesh as shown in  FIG.  53 B . 
     It&#39;s worth noting that in this embodiment the length  836  of a portion of each conductive part  839  that immediately connects to the anode of an LED  831  is smaller than the length  837  of another portion of each conductive part  839  that immediately connects to the cathode of an LED  831 , making the area of the latter portion immediately connecting to the cathode larger than that of the former portion immediately connecting to the anode. The length  837  may be smaller than a length  838  of a portion of each conductive part  839  that immediately connects the cathode of an LED  831  and the anode of the next LED  831 , making the area of the portion of each conductive part  839  that immediately connects a cathode and an anode larger than the area of any other portion of each conductive part  839  that immediately connects to only a cathode or an anode of an LED  831 . Due to the length differences and area differences, this layout structure improves heat dissipation of the LEDs  831 . 
     In some embodiments, positive conductive line  834  includes a lengthwise portion  834   a , and negative conductive line  835  includes a lengthwise portion  835   a , which are conducive to making the LED module have a positive “+” connective portion and a negative “−” connective portion at each of the two ends of the LED module, as shown in  FIG.  53 C . Such a layout structure allows for coupling any of other circuits of the power supply module of the LED lamp, including e.g. filtering circuit  520  and rectifying circuits  510  and  540 , to the LED module through the positive connective portion and/or the negative connective portion at each or both ends of the LED lamp. Thus the layout structure increases the flexibility in arranging actual circuits in the LED lamp. 
       FIG.  53 D  is a plan view of a circuit layout of the LED module according to another embodiment of the present invention. Referring to  FIG.  53 D , in this embodiment LEDs  931  are connected in the same way as described in  FIG.  53 A , and three LED units each including 7 LEDs  931  are assumed in LED module  630  and described as follows for illustration. A positive conductive line  934  and a negative conductive line  935  are to receive a driving signal, for supplying power to the LEDs  931 . For example, positive conductive line  934  may be coupled to the filtering output terminal  521  of the filtering circuit  520  described above, and negative conductive line  935  coupled to the filtering output terminal  522  of the filtering circuit  520 , to receive a filtered signal. For the convenience of illustration, all seven LEDs  931  of each of the three LED units are grouped as an LED set  932  in  FIG.  53 D . Thus there are three LED sets  932  corresponding to the three LED units. 
     Positive conductive line  934  connects to the anode on the left side of the first or leftmost LED  931  of each of the three LED sets  932 . Negative conductive line  935  connects to the cathode on the right side of the last or rightmost LED  931  of each of the three LED sets  932 . In each LED set  932 , of two consecutive LEDs  931  the LED  931  on the left has a cathode connected by a conductive part  939  to an anode of the LED  931  on the right. By such a layout, the LEDs  931  of each LED set  932  are connected in series. 
     It&#39;s also worth noting that a conductive part  939  may be used to connect an anode and a cathode respectively of two consecutive LEDs  931 . Negative conductive line  935  connects to the cathode of the last or rightmost LED  931  of each of the three LED sets  932 . And positive conductive line  934  connects to the anode of the first or leftmost LED  931  of each of the three LED sets  932 . Therefore, as shown in  FIG.  53 D , the length (and thus area) of the conductive part  939  is larger than that of the portion of negative conductive line  935  immediately connecting to a cathode, which length (and thus area) is then larger than that of the portion of positive conductive line  934  immediately connecting to an anode. For example, the length  938  of the conductive part  939  may be larger than the length  937  of the portion of negative conductive line  935  immediately connecting to a cathode of an LED  931 , which length  937  is then larger than the length  936  of the portion of positive conductive line  934  immediately connecting to an anode of an LED  931 . Such a layout structure improves heat dissipation of the LEDs  931  in LED module  630 . 
     Positive conductive line  934  may include a lengthwise portion  934   a , and negative conductive line  935  may include a lengthwise portion  935   a , which are conducive to making the LED module have a positive “+” connective portion and a negative “−” connective portion at each of the two ends of the LED module, as shown in  FIG.  53 D . Such a layout structure allows for coupling any of other circuits of the power supply module of the LED lamp, including e.g. filtering circuit  520  and rectifying circuits  510  and  540 , to the LED module through the positive connective portion  934   a  and/or the negative connective portion  935   a  at each or both ends of the LED lamp. Thus the layout structure increases the flexibility in arranging actual circuits in the LED lamp. 
     Further, the circuit layouts as shown in  FIGS.  53 C and  53 D  may be implemented with a bendable circuit sheet or substrate, which may even be called flexible circuit board depending on its specific definition used. For example, the bendable circuit sheet may comprise one conductive layer where positive conductive line  834 , positive lengthwise portion  834   a , negative conductive line  835 , negative lengthwise portion  835   a , and conductive parts  839  shown in  FIG.  53 C , and positive conductive line  934 , positive lengthwise portion  934   a , negative conductive line  935 , negative lengthwise portion  935   a , and conductive parts  939  shown in  FIG.  53 D  are formed by the method of etching. 
       FIG.  53 E  is a plan view of a circuit layout of the LED module according to another embodiment of the present invention. The layout structures of the LED module in  FIGS.  53 E and  53 C  each correspond to the same way of connecting LEDs  831  as that shown in  FIG.  53 B , but the layout structure in  FIG.  53 E  comprises two conductive layers, instead of only one conductive layer for forming the circuit layout as shown in  FIG.  53 C . Referring to  FIG.  53 E , the main difference from the layout in  FIG.  53 C  is that positive conductive line  834  and negative conductive line  835  have a lengthwise portion  834   a  and a lengthwise portion  835   a , respectively, that are formed in a second conductive layer instead. The difference is elaborated as follows. 
     Referring to  FIG.  53 E , the bendable circuit sheet of the LED module comprises a first conductive layer  2   a  and a second conductive layer  2   c  electrically insulated from each other by a dielectric layer  2   b  (not shown). Of the two conductive layers, positive conductive line  834 , negative conductive line  835 , and conductive parts  839  in  FIG.  53 E  are formed in first conductive layer  2   a  by the method of etching for electrically connecting the plurality of LED components  831  e.g. in a form of a mesh, whereas positive lengthwise portion  834   a  and negative lengthwise portion  835   a  are formed in second conductive layer  2   c  by etching for electrically connecting to (the filtering output terminal of) the filtering circuit. Further, positive conductive line  834  and negative conductive line  835  in first conductive layer  2   a  have via points  834   b  and via points  835   b , respectively, for connecting to second conductive layer  2   c . And positive lengthwise portion  834   a  and negative lengthwise portion  835   a  in second conductive layer  2   c  have via points  834   c  and via points  835   c , respectively. Via points  834   b  are positioned corresponding to via points  834   c , for connecting positive conductive line  834  and positive lengthwise portion  834   a . Via points  835   b  are positioned corresponding to via points  835   c , for connecting negative conductive line  835  and negative lengthwise portion  835   a . A preferable way of connecting the two conductive layers is to form a hole connecting each via point  834   b  and a corresponding via point  834   c , and to form a hole connecting each via point  835   b  and a corresponding via point  835   c , with the holes extending through the two conductive layers and the dielectric layer in-between. And positive conductive line  834  and positive lengthwise portion  834   a  can be electrically connected by welding metallic part(s) through the connecting hole(s), and negative conductive line  835  and negative lengthwise portion  835   a  can be electrically connected by welding metallic part(s) through the connecting hole(s). 
     Similarly, the layout structure of the LED module in  FIG.  53 D  may alternatively have positive lengthwise portion  934   a  and negative lengthwise portion  935   a  disposed in a second conductive layer, to constitute a two-layer layout structure. 
     It&#39;s worth noting that the thickness of the second conductive layer of a two-layer bendable circuit sheet is in some embodiments larger than that of the first conductive layer, in order to reduce the voltage drop or loss along each of the positive lengthwise portion and the negative lengthwise portion disposed in the second conductive layer. Compared to a one-layer bendable circuit sheet, since a positive lengthwise portion and a negative lengthwise portion are disposed in a second conductive layer in a two-layer bendable circuit sheet, the width (between two lengthwise sides) of the two-layer bendable circuit sheet is or can be reduced. On the same fixture or plate in a production process, the number of bendable circuit sheets each with a shorter width that can be laid together at most is larger than the number of bendable circuit sheets each with a longer width that can be laid together at most. Thus adopting a bendable circuit sheet with a shorter width can increase the efficiency of production of the LED module. And reliability in the production process, such as the accuracy of welding position when welding (materials on) the LED components, can also be improved, because a two-layer bendable circuit sheet can better maintain its shape. 
     As a variant of the above embodiments, a type of LED tube lamp is provided that has at least some of the electronic components of its power supply module disposed on a light strip of the LED tube lamp. For example, the technique of printed electronic circuit (PEC) can be used to print, insert, or embed at least some of the electronic components onto the light strip. 
     In one embodiment, all electronic components of the power supply module are disposed on the light strip. The production process may include or proceed with the following steps: preparation of the circuit substrate (e.g. preparation of a flexible printed circuit board); ink jet printing of metallic nano-ink; ink jet printing of active and passive components (as of the power supply module); drying/sintering; ink jet printing of interlayer bumps; spraying of insulating ink; ink jet printing of metallic nano-ink; ink jet printing of active and passive components (to sequentially form the included layers); spraying of surface bond pad(s); and spraying of solder resist against LED components. 
     In certain embodiments, if all electronic components of the power supply module are disposed on the light strip, electrical connection between terminal pins of the LED tube lamp and the light strip may be achieved by connecting the pins to conductive lines which are welded with ends of the light strip. In this case, another substrate for supporting the power supply module is not required, thereby allowing an improved design or arrangement in the end cap(s) of the LED tube lamp. In some embodiments, (components of) the power supply module are disposed at two ends of the light strip, in order to significantly reduce the impact of heat generated from the power supply module&#39;s operations on the LED components. Since no substrate other than the light strip is used to support the power supply module in this case, the total amount of welding or soldering can be significantly reduced, improving the general reliability of the power supply module. 
     Another case is that some of all electronic components of the power supply module, such as some resistors and/or smaller size capacitors, are printed onto the light strip, and some bigger size components, such as some inductors and/or electrolytic capacitors, are disposed in the end cap(s). The production process of the light strip in this case may be the same as that described above. And in this case disposing some of all electronic components on the light strip is conducive to achieving a reasonable layout of the power supply module in the LED tube lamp, which may allow of an improved design in the end cap(s). 
     As a variant embodiment of the above, electronic components of the power supply module may be disposed on the light strip by a method of embedding or inserting, e.g. by embedding the components onto a bendable or flexible light strip. In some embodiments, this embedding may be realized by a method using copper-clad laminates (CCL) for forming a resistor or capacitor; a method using ink related to silkscreen printing; or a method of ink jet printing to embed passive components, wherein an ink jet printer is used to directly print inks to constitute passive components and related functionalities to intended positions on the light strip. Then through treatment by ultraviolet (UV) light or drying/sintering, the light strip is formed where passive components are embedded. The electronic components embedded onto the light strip include for example resistors, capacitors, and inductors. In other embodiments, active components also may be embedded. Through embedding some components onto the light strip, a reasonable layout of the power supply module can be achieved to allow of an improved design in the end cap(s), because the surface area on a printed circuit board used for carrying components of the power supply module is reduced or smaller, and as a result the size, weight, and thickness of the resulting printed circuit board for carrying components of the power supply module is also smaller or reduced. Also, in this situation since welding points on the printed circuit board for welding resistors and/or capacitors if they were not to be disposed on the light strip are no longer used, the reliability of the power supply module is improved, in view of the fact that these welding points are most liable to (cause or incur) faults, malfunctions, or failures. Further, the length of conductive lines needed for connecting components on the printed circuit board is therefore also reduced, which allows of a more compact layout of components on the printed circuit board and thus improving the functionalities of these components. 
     Next, methods to produce embedded capacitors and resistors are explained as follows. 
     Usually, methods for manufacturing embedded capacitors employ or involve a concept called distributed or planar capacitance. The manufacturing process may include the following step(s). On a substrate of a copper layer a very thin insulation layer is applied or pressed, which is then generally disposed between a pair of layers including a power conductive layer and a ground layer. The very thin insulation layer makes the distance between the power conductive layer and the ground layer very short. A capacitance resulting from this structure can also be realized by a conventional technique of a plated-through hole. Basically, this step is used to create this structure comprising a big parallel-plate capacitor on a circuit substrate. 
     Of products of high electrical capacity, certain types of products employ distributed capacitances, and other types of products employ separate embedded capacitances. Through putting or adding a high dielectric-constant material such as barium titanate into the insulation layer, the high electrical capacity is achieved. 
     A usual method for manufacturing embedded resistors employ conductive or resistive adhesive. This may include, for example, a resin to which conductive carbon or graphite is added, which may be used as an additive or filler. The additive resin is silkscreen printed to an object location, and is then after treatment laminated inside the circuit board. The resulting resistor is connected to other electronic components through plated-through holes or microvias. Another method is called Ohmega-Ply, by which a two metallic layer structure of a copper layer and a thin nickel alloy layer constitutes a layer resistor relative to a substrate. Then through etching the copper layer and nickel alloy layer, different types of nickel alloy resistors with copper terminals can be formed. These types of resistor are each laminated inside the circuit board. 
     In an embodiment, conductive wires/lines are directly printed in a linear layout on an inner surface of the LED glass lamp tube, with LED components directly attached on the inner surface and electrically connected by the conductive wires. In some embodiments, the LED components in the form of chips are directly attached over the conductive wires on the inner surface, and connective points are at terminals of the wires for connecting the LED components and the power supply module. After being attached, the LED chips may have fluorescent powder applied or dropped thereon, for producing white light or light of other color by the operating LED tube lamp. 
     In some embodiments, luminous efficacy of the LED or LED component is 80 lm/W or above, and in some embodiments, it may be preferably 120 lm/W or above. Certain more optimal embodiments may include a luminous efficacy of the LED or LED component of 160 lm/W or above. White light emitted by an LED component in the invention may be produced by mixing fluorescent powder with the monochromatic light emitted by a monochromatic LED chip. The white light in its spectrum has major wavelength ranges of 430-460 nm and 550-560 nm, or major wavelength ranges of 430-460 nm, 540-560 nm, and 620-640 nm. 
       FIG.  54 A  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. As shown in  FIG.  54 A , the power supply module of the LED lamp includes rectifying circuits  510  and  540 , a filtering circuit  520 , and an LED driving module  530 . LED driving module  530  in this embodiment comprises a driving circuit  1530  and an LED module  630 . According to the above description in  FIG.  49 E , driving circuit  1530  in  FIG.  54 A  comprises a DC-to-DC converter circuit, and is coupled to filtering output terminals  521  and  522  to receive a filtered signal and then perform power conversion for converting the filtered signal into a driving signal at driving output terminals  1521  and  1522 . The LED module  630  is coupled to driving output terminals  1521  and  1522  to receive the driving signal for emitting light. In some embodiments, the current of LED module  630  is stabilized at an objective current value. Descriptions of this LED module  630  are the same as those provided above with reference to  FIGS.  53 A- 53 D . 
     It&#39;s worth noting that rectifying circuit  540  is an optional element and therefore can be omitted, so it is depicted in a dotted line in  FIG.  54 A . Accordingly, LED driving module  530  in embodiments of  FIGS.  54 A,  54 C, and  54 E  may comprise a driving circuit  1530  and an LED module  630 . Therefore, the power supply module of the LED lamp in this embodiment can be used with a single-end power supply coupled to one end of the LED lamp, and can be used with a dual-end power supply coupled to two ends of the LED lamp. With a single-end power supply, examples of the LED lamp include an LED light bulb, a personal area light (PAL), etc. 
       FIG.  54 B  is a block diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 B , the driving circuit includes a controller  1531 , and a conversion circuit  1532  for power conversion based on a current source, for driving the LED module to emit light. Conversion circuit  1532  includes a switching circuit  1535  and an energy storage circuit  1538 . And conversion circuit  1532  is coupled to filtering output terminals  521  and  522  to receive and then convert a filtered signal, under the control by controller  1531 , into a driving signal at driving output terminals  1521  and  1522  for driving the LED module. Under the control by controller  1531 , the driving signal output by conversion circuit  1532  comprises a steady current, making the LED module emitting steady light. 
       FIG.  54 C  is a schematic diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 C , a driving circuit  1630  in this embodiment comprises a buck DC-to-DC converter circuit having a controller  1631  and a converter circuit. The converter circuit includes an inductor  1632 , a diode  1633  for “freewheeling” of current, a capacitor  1634 , and a switch  1635 . Driving circuit  1630  is coupled to filtering output terminals  521  and  522  to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals  1521  and  1522 . 
     In this embodiment, switch  1635  comprises a metal-oxide-semiconductor field-effect transistor (MOSFET) and has a first terminal coupled to the anode of freewheeling diode  1633 , a second terminal coupled to filtering output terminal  522 , and a control terminal coupled to controller  1631  used for controlling current conduction or cutoff between the first and second terminals of switch  1635 . Driving output terminal  1521  is connected to filtering output terminal  521 , and driving output terminal  1522  is connected to an end of inductor  1632 , which has another end connected to the first terminal of switch  1635 . Capacitor  1634  is coupled between driving output terminals  1521  and  1522 , to stabilize the voltage between driving output terminals  1521  and  1522 . Freewheeling diode  1633  has a cathode connected to driving output terminal  1521 . 
     Next, a description follows as to an exemplary operation of driving circuit  1630 . 
     Controller  1631  is configured for determining when to turn switch  1635  on (in a conducting state) or off (in a cutoff state), according to a current detection signal S 535  and/or a current detection signal S 531 . For example, in some embodiments, controller  1631  is configured to control the duty cycle of switch  1635  being on and switch  1635  being off, in order to adjust the size or magnitude of the driving signal. Current detection signal S 535  represents the magnitude of current through switch  1635 . Current detection signal S 531  represents the magnitude of current through the LED module coupled between driving output terminals  1521  and  1522 . According to any of current detection signal S 535  and current detection signal S 531 , controller  1631  can obtain information on the magnitude of power converted by the converter circuit. When switch  1635  is switched on, a current of a filtered signal is input through filtering output terminal  521 , and then flows through capacitor  1634 , driving output terminal  1521 , the LED module, inductor  1632 , and switch  1635 , and then flows out from filtering output terminal  522 . During this flowing of current, capacitor  1634  and inductor  1632  are performing storing of energy. On the other hand, when switch  1635  is switched off, capacitor  1634  and inductor  1632  perform releasing of stored energy by a current flowing from freewheeling capacitor  1633  to driving output terminal  1521  to make the LED module continuing to emit light. 
     It&#39;s worth noting that capacitor  1634  is an optional element, so it can be omitted and is thus depicted in a dotted line in  FIG.  54 C . In some application environments, the natural characteristic of an inductor to oppose instantaneous change in electric current passing through the inductor may be used to achieve the effect of stabilizing the current through the LED module, thus omitting capacitor  1634 . 
       FIG.  54 D  is a schematic diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 D , a driving circuit  1730  in this embodiment comprises a boost DC-to-DC converter circuit having a controller  1731  and a converter circuit. The converter circuit includes an inductor  1732 , a diode  1733  for “freewheeling” of current, a capacitor  1734 , and a switch  1735 . Driving circuit  1730  is configured to receive and then convert a filtered signal from filtering output terminals  521  and  522  into a driving signal for driving an LED module coupled between driving output terminals  1521  and  1522 . 
     Inductor  1732  has an end connected to filtering output terminal  521 , and another end connected to the anode of freewheeling diode  1733  and a first terminal of switch  1735 , which has a second terminal connected to filtering output terminal  522  and driving output terminal  1522 . Freewheeling diode  1733  has a cathode connected to driving output terminal  1521 . And capacitor  1734  is coupled between driving output terminals  1521  and  1522 . 
     Controller  1731  is coupled to a control terminal of switch  1735  and is configured for determining when to turn switch  1735  on (in a conducting state) or off (in a cutoff state), according to a current detection signal S 535  and/or a current detection signal S 531 . When switch  1735  is switched on, a current of a filtered signal is input through filtering output terminal  521 , and then flows through inductor  1732  and switch  1735 , and then flows out from filtering output terminal  522 . During this flowing of current, the current through inductor  1732  increases with time, with inductor  1732  being in a state of storing energy, while capacitor  1734  enters a state of releasing energy, making the LED module continuing to emit light. On the other hand, when switch  1735  is switched off, inductor  1732  enters a state of releasing energy as the current through inductor  1732  decreases with time. In this state, the current through inductor  1732  then flows through freewheeling diode  1733 , capacitor  1734 , and the LED module, while capacitor  1734  enters a state of storing energy. 
     It&#39;s worth noting that capacitor  1734  is an optional element, so it can be omitted and is thus depicted in a dotted line in  FIG.  54 D . When capacitor  1734  is omitted and switch  1735  is switched on, the current of inductor  1732  does not flow through the LED module, making the LED module not emit light; but when switch  1735  is switched off, the current of inductor  1732  flows through freewheeling diode  1733  to reach the LED module, making the LED module emit light. Therefore, by controlling the time that the LED module emits light, and the magnitude of current through the LED module, the average luminance of the LED module can be stabilized to be above a defined value, thus also achieving the effect of emitting a steady light. 
       FIG.  54 E  is a schematic diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 E , a driving circuit  1830  in this embodiment comprises a buck DC-to-DC converter circuit having a controller  1831  and a converter circuit. The converter circuit includes an inductor  1832 , a diode  1833  for “freewheeling” of current, a capacitor  1834 , and a switch  1835 . Driving circuit  1830  is coupled to filtering output terminals  521  and  522  to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals  1521  and  1522 . 
     Switch  1835  has a first terminal coupled to filtering output terminal  521 , a second terminal coupled to the cathode of freewheeling diode  1833 , and a control terminal coupled to controller  1831  to receive a control signal from controller  1831  for controlling current conduction or cutoff between the first and second terminals of switch  1835 . The anode of freewheeling diode  1833  is connected to filtering output terminal  522  and driving output terminal  1522 . Inductor  1832  has an end connected to the second terminal of switch  1835 , and another end connected to driving output terminal  1521 . Capacitor  1834  is coupled between driving output terminals  1521  and  1522 , to stabilize the voltage between driving output terminals  1521  and  1522 . 
     Controller  1831  is configured for controlling when to turn switch  1835  on (in a conducting state) or off (in a cutoff state), according to a current detection signal S 535  and/or a current detection signal S 531 . When switch  1835  is switched on, a current of a filtered signal is input through filtering output terminal  521 , and then flows through switch  1835 , inductor  1832 , and driving output terminals  1521  and  1522 , and then flows out from filtering output terminal  522 . During this flowing of current, the current through inductor  1832  and the voltage of capacitor  1834  both increase with time, so inductor  1832  and capacitor  1834  are in a state of storing energy. On the other hand, when switch  1835  is switched off, inductor  1832  is in a state of releasing energy and thus the current through it decreases with time. In this case, the current through inductor  1832  circulates through driving output terminals  1521  and  1522 , freewheeling diode  1833 , and back to inductor  1832 . 
     It&#39;s worth noting that capacitor  1834  is an optional element, so it can be omitted and is thus depicted in a dotted line in  FIG.  54 E . When capacitor  1834  is omitted, no matter whether switch  1835  is turned on or off, the current through inductor  1832  will flow through driving output terminals  1521  and  1522  to drive the LED module to continue emitting light. 
       FIG.  54 F  is a schematic diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 F , a driving circuit  1930  in this embodiment comprises a buck DC-to-DC converter circuit having a controller  1931  and a converter circuit. The converter circuit includes an inductor  1932 , a diode  1933  for “freewheeling” of current, a capacitor  1934 , and a switch  1935 . Driving circuit  1930  is coupled to filtering output terminals  521  and  522  to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals  1521  and  1522 . 
     Inductor  1932  has an end connected to filtering output terminal  521  and driving output terminal  1522 , and another end connected to a first end of switch  1935 . Switch  1935  has a second end connected to filtering output terminal  522 , and a control terminal connected to controller  1931  to receive a control signal from controller  1931  for controlling current conduction or cutoff of switch  1935 . Freewheeling diode  1933  has an anode coupled to a node connecting inductor  1932  and switch  1935 , and a cathode coupled to driving output terminal  1521 . Capacitor  1934  is coupled to driving output terminals  1521  and  1522 , to stabilize the driving of the LED module coupled between driving output terminals  1521  and  1522 . 
     Controller  1931  is configured for controlling when to turn switch  1935  on (in a conducting state) or off (in a cutoff state), according to a current detection signal S 531  and/or a current detection signal S 535 . When switch  1935  is turned on, a current is input through filtering output terminal  521 , and then flows through inductor  1932  and switch  1935 , and then flows out from filtering output terminal  522 . During this flowing of current, the current through inductor  1932  increases with time, so inductor  1932  is in a state of storing energy; but the voltage of capacitor  1934  decreases with time, so capacitor  1934  is in a state of releasing energy to keep the LED module continuing to emit light. On the other hand, when switch  1935  is turned off, inductor  1932  is in a state of releasing energy and its current decreases with time. In this case, the current through inductor  1932  circulates through freewheeling diode  1933 , driving output terminals  1521  and  1522 , and back to inductor  1932 . During this circulation, capacitor  1934  is in a state of storing energy and its voltage increases with time. 
     It&#39;s worth noting that capacitor  1934  is an optional element, so it can be omitted and is thus depicted in a dotted line in  FIG.  54 F . When capacitor  1934  is omitted and switch  1935  is turned on, the current through inductor  1932  does not flow through driving output terminals  1521  and  1522 , thereby making the LED module not emit light. On the other hand, when switch  1935  is turned off, the current through inductor  1932  flows through freewheeling diode  1933  and then the LED module to make the LED module emit light. Therefore, by controlling the time that the LED module emits light, and the magnitude of current through the LED module, the average luminance of the LED module can be stabilized to be above a defined value, thus also achieving the effect of emitting a steady light. 
       FIG.  54 G  is a block diagram of the driving circuit according to an embodiment of the present invention. Referring to  FIG.  54 G , the driving circuit includes a controller  2631 , and a conversion circuit  2632  for power conversion based on an adjustable current source, for driving the LED module to emit light. Conversion circuit  2632  includes a switching circuit  2635  and an energy storage circuit  2638 . And conversion circuit  2632  is coupled to filtering output terminals  521  and  522  to receive and then convert a filtered signal, under the control by controller  2631 , into a driving signal at driving output terminals  1521  and  1522  for driving the LED module. Controller  2631  is configured to receive a current detection signal S 535  and/or a current detection signal S 539 , for controlling or stabilizing the driving signal output by conversion circuit  2632  to be above an objective current value. Current detection signal S 535  represents the magnitude of current through switching circuit  2635 . Current detection signal S 539  represents the magnitude of current through energy storage circuit  2638 , which current may be e.g. an inductor current in energy storage circuit  2638  or a current output at driving output terminal  1521 . Any of current detection signal S 535  and current detection signal S 539  can represent the magnitude of current Iout provided by the driving circuit from driving output terminals  1521  and  1522  to the LED module. Controller  2631  is coupled to filtering output terminal  521  for setting the objective current value according to the voltage Vin at filtering output terminal  521 . Therefore, the current Iout provided by the driving circuit or the objective current value can be adjusted corresponding to the magnitude of the voltage Vin of a filtered signal output by a filtering circuit. 
     It&#39;s worth noting that current detection signals S 535  and S 539  can be generated by measuring current through a resistor or induced by an inductor. For example, a current can be measured according to a voltage drop across a resistor in conversion circuit  2632  the current flows through, or which arises from a mutual induction between an inductor in conversion circuit  2632  and another inductor in its energy storage circuit  2638 . 
     The above driving circuit structures are especially suitable for an application environment in which the external driving circuit for the LED tube lamp includes electronic ballast. An electronic ballast is equivalent to a current source whose output power is not constant. In an internal driving circuit as shown in each of  FIGS.  54 C- 54 F , power consumed by the internal driving circuit relates to or depends on the number of LEDs in the LED module, and could be regarded as constant. When the output power of the electronic ballast is higher than power consumed by the LED module driven by the driving circuit, the output voltage of the ballast will increase continually, causing the level of an AC driving signal received by the power supply module of the LED lamp to continually increase, so as to risk damaging the ballast and/or components of the power supply module due to their voltage ratings being exceeded. On the other hand, when the output power of the electronic ballast is lower than power consumed by the LED module driven by the driving circuit, the output voltage of the ballast and the level of the AC driving signal will decrease continually so that the LED tube lamp fail to normally operate. 
     It&#39;s worth noting that the power needed for an LED lamp to work is already lower than that needed for a fluorescent lamp to work. If a conventional control mechanism of e.g. using a backlight module to control the LED luminance is used with a conventional driving system of e.g. a ballast, a problem will probably arise of mismatch or incompatibility between the output power of the external driving system and the power needed by the LED lamp. This problem may even cause damaging of the driving system and/or the LED lamp. To prevent this problem, using e.g. the power/current adjustment method described above in  FIG.  54 G  enables the LED (tube) lamp to be better compatible with traditional fluorescent lighting system. 
       FIG.  54 H  is a graph illustrating the relationship between the voltage Vin and the objective current value Iout according to an embodiment of the present invention. In  FIG.  54 H , the variable Vin is on the horizontal axis, and the variable Iout is on the vertical axis. In some cases, when the level of the voltage Vin of a filtered signal is between the upper voltage limit VH and the lower voltage limit VL, the objective current value Iout will be about an initial objective current value. The upper voltage limit VH is higher than the lower voltage limit VL. When the voltage Vin increases to be higher than the upper voltage limit VH, the objective current value Iout will increase with the increasing of the voltage Vin. During this stage, a situation that may be preferable is that the slope of the relationship curve increase with the increasing of the voltage Vin. When the voltage Vin of a filtered signal decreases to be below the lower voltage limit VL, the objective current value Iout will decrease with the decreasing of the voltage Vin. During this stage, a situation that may be preferable is that the slope of the relationship curve decrease with the decreasing of the voltage Vin. For example, during the stage when the voltage Vin is higher than the upper voltage limit VH or lower than the lower voltage limit VL, the objective current value Iout is in some embodiments a function of the voltage Vin to the power of 2 or above, in order to make the rate of increase/decrease of the consumed power higher than the rate of increase/decrease of the output power of the external driving system. Thus, adjustment of the objective current value Iout is in some embodiments a function of the filtered voltage Vin to the power of 2 or above. 
     In another case, when the voltage Vin of a filtered signal is between the upper voltage limit VH and the lower voltage limit VL, the objective current value Iout of the LED lamp will vary, increase or decrease, linearly with the voltage Vin. During this stage, when the voltage Vin is at the upper voltage limit VH, the objective current value Iout will be at the upper current limit IH. When the voltage Vin is at the lower voltage limit VL, the objective current value Iout will be at the lower current limit IL. The upper current limit IH is larger than the lower current limit IL. And when the voltage Vin is between the upper voltage limit VH and the lower voltage limit VL, the objective current value Iout will be a function of the voltage Vin to the power of 1. 
     With the designed relationship in  FIG.  54 H , when the output power of the ballast is higher than the power consumed by the LED module driven by the driving circuit, the voltage Vin will increase with time to exceed the upper voltage limit VH. When the voltage Vin is higher than the upper voltage limit VH, the rate of increase of the consumed power of the LED module is higher than that of the output power of the electronic ballast, and the output power and the consumed power will be balanced or equal when the voltage Vin is at a high balance voltage value VH+ and the current Iout is at a high balance current value IH+. In this case, the high balance voltage value VH+ is larger than the upper voltage limit VH, and the high balance current value IH+ is larger than the upper current limit IH. On the other hand, when the output power of the ballast is lower than the power consumed by the LED module driven by the driving circuit, the voltage Vin will decrease to be below the lower voltage limit VL. When the voltage Vin is lower than the lower voltage limit VL, the rate of decrease of the consumed power of the LED module is higher than that of the output power of the electronic ballast, and the output power and the consumed power will be balanced or equal when the voltage Vin is at a low balance voltage value VL− and the objective current value Iout is at a low balance current value IL−. In this case, the low balance voltage value VL− is smaller than the lower voltage limit VL, and the low balance current value IL− is smaller than the lower current limit IL. 
     In some embodiments, the lower voltage limit VL is defined to be around 90% of the lowest output power of the electronic ballast, and the upper voltage limit VH is defined to be around 110% of its highest output power. Taking a common AC powerline with a voltage range of 100-277 volts and a frequency of 60 Hz as an example, the lower voltage limit VL may be set at 90 volts (=100*90%), and the upper voltage limit VH may be set at 305 volts (=277*110%). 
     With reference to  FIGS.  35  and  36   , a short circuit board  253  includes a first short circuit substrate and a second short circuit substrate respectively connected to two terminal portions of a long circuit sheet  251 , and electronic components of the power supply module are respectively disposed on the first short circuit substrate and the second short circuit substrate. The first short circuit substrate and the second short circuit substrate may have roughly the same length, or different lengths. In general, the first short circuit substrate (i.e. the right circuit substrate of short circuit board  253  in  FIG.  35    and the left circuit substrate of short circuit board  253  in  FIG.  36   ) has a length that is about 30%-80% of the length of the second short circuit substrate (i.e. the left circuit substrate of short circuit board  253  in  FIG.  35    and the right circuit substrate of short circuit board  253  in  FIG.  36   ). In some embodiments the length of the first short circuit substrate is about ⅓˜⅔ of the length of the second short circuit substrate. For example, in one embodiment, the length of the first short circuit substrate may be about half the length of the second short circuit substrate. The length of the second short circuit substrate may be, for example in the range of about 15 mm to about 65 mm, depending on actual application occasions. In certain embodiments, the first short circuit substrate is disposed in an end cap at an end of the LED tube lamp, and the second short circuit substrate is disposed in another end cap at the opposite end of the LED tube lamp. 
     For example, capacitors of the driving circuit, such as capacitors  1634 ,  1734 ,  1834 , and  1934  in  FIGS.  54 C ˜ 54 F, in practical use may include two or more capacitors connected in parallel. Some or all capacitors of the driving circuit in the power supply module may be arranged on the first short circuit substrate of short circuit board  253 , while other components such as the rectifying circuit, filtering circuit, inductor(s) of the driving circuit, controller(s), switch(es), diodes, etc. are arranged on the second short circuit substrate of short circuit board  253 . Since inductors, controllers, switches, etc. are electronic components with higher temperature, arranging some or all capacitors on a circuit substrate separate or away from the circuit substrate(s) of high-temperature components helps prevent the working life of capacitors (especially electrolytic capacitors) from being negatively affected by the high-temperature components, thus improving the reliability of the capacitors. Further, the physical separation between the capacitors and both the rectifying circuit and filtering circuit also contributes to reducing the problem of EMI. 
     In some embodiments, the driving circuit has power conversion efficiency of 80% or above, which may preferably be 90% or above, and may even more preferably be 92% or above. Therefore, without the driving circuit, luminous efficacy of the LED lamp according to some embodiments may preferably be 120 lm/W or above, and may even more preferably be 160 lm/W or above. On the other hand, with the driving circuit in combination with the LED component(s), luminous efficacy of the LED lamp in the invention may preferably be, in some embodiments, 120 lm/W*90%=108 lm/W or above, and may even more preferably be, in some embodiments 160 lm/W*92%=147.2 lm/W or above. 
     In view of the fact that the diffusion film or layer in an LED tube lamp has light transmittance of 85% or above, luminous efficacy of the LED tube lamp of the invention is in some embodiments 108 lm/W*85%=91.8 lm/W or above, and may be, in some more effective embodiments, 147.2 lm/W*85%=125.12 lm/W. 
       FIG.  55 A  is a block diagram of using a power supply module in an LED lamp according to an embodiment of the present invention. Compared to  FIG.  54 A , the embodiment of  FIG.  55 A  includes rectifying circuits  510  and  540 , a filtering circuit  520 , and an LED driving module  530 , and further includes an anti-flickering circuit  550  coupled between filtering circuit  520  and LED driving module  530 . It&#39;s noted that rectifying circuit  540  may be omitted and is thus depicted in a dotted line in  FIG.  55 A . 
     Anti-flickering circuit  550  is coupled to filtering output terminals  521  and  522 , to receive a filtered signal, and under specific circumstances to consume partial energy of the filtered signal so as to reduce (the incidence of) ripples of the filtered signal disrupting or interrupting the light emission of the LED driving module  530 . In general, filtering circuit  520  has such filtering components as resistor(s) and/or inductor(s), and/or parasitic capacitors and inductors, which may form resonant circuits. Upon breakoff or stop of an AC power signal, as when the power supply of the LED lamp is turned off by a user, the amplitude(s) of resonant signals in the resonant circuits will decrease with time. But LEDs in the LED module of the LED lamp are unidirectional conduction devices and require a minimum conduction voltage for the LED module. When a resonant signal&#39;s trough value is lower than the minimum conduction voltage of the LED module, but its peak value is still higher than the minimum conduction voltage, the flickering phenomenon will occur in light emission of the LED module. In this case anti-flickering circuit  550  works by allowing a current matching a defined flickering current value of the LED component to flow through, consuming partial energy of the filtered signal which should be higher than the energy difference of the resonant signal between its peak and trough values, so as to reduce the flickering phenomenon. In certain embodiments, a preferred occasion for anti-flickering circuit  550  to work is when the filtered signal&#39;s voltage approaches (and is still higher than) the minimum conduction voltage. 
     It&#39;s worth noting that anti-flickering circuit  550  may be more suitable for the situation in which LED driving module  530  does not include driving circuit  1530 , for example, when LED module  630  of LED driving module  530  is (directly) driven to emit light by a filtered signal from a filtering circuit. In this case, the light emission of LED module  630  will directly reflect variation in the filtered signal due to its ripples. In this situation, the introduction of anti-flickering circuit  550  will prevent the flickering phenomenon from occurring in the LED lamp upon the breakoff of power supply to the LED lamp. 
       FIG.  55 B  is a schematic diagram of the anti-flickering circuit according to an embodiment of the present invention. Referring to  FIG.  55 B , anti-flickering circuit  650  includes at least a resistor, such as two resistors connected in series between filtering output terminals  521  and  522 . In this embodiment, anti-flickering circuit  650  in use consumes partial energy of a filtered signal continually. When in normal operation of the LED lamp, this partial energy is far lower than the energy consumed by LED driving module  530 . But upon a breakoff or stop of the power supply, when the voltage level of the filtered signal decreases to approach the minimum conduction voltage of LED module  630 , this partial energy is still consumed by anti-flickering circuit  650  in order to offset the impact of the resonant signals which may cause the flickering of light emission of LED module  630 . In some embodiments, a current equal to or larger than an anti-flickering current level may be set to flow through anti-flickering circuit  650  when LED module  630  is supplied by the minimum conduction voltage, and then an equivalent anti-flickering resistance of anti-flickering circuit  650  can be determined based on the set current. 
       FIG.  56 A  is a block diagram of using a power supply module in an LED lamp according to an embodiment of the present invention. Compared to  FIG.  55 A , the embodiment of  FIG.  56 A  includes rectifying circuits  510  and  540 , a filtering circuit  520 , an LED driving module  530 , and an anti-flickering circuit  550 , and further includes a protection circuit  560 . Protection circuit  560  is coupled to filtering output terminals  521  and  522 , to detect the filtered signal from filtering circuit  520  for determining whether to enter a protection state. Upon entering a protection state, protection circuit  560  works to limit, restrain, or clamp down on the level of the filtered signal, preventing damaging of components in LED driving module  530 . And rectifying circuit  540  and anti-flickering circuit  550  may be omitted and are thus depicted in a dotted line in  FIG.  56 A . 
       FIG.  56 B  is a schematic diagram of the protection circuit according to an embodiment of the present invention. Referring to  FIG.  56 B , a protection circuit  660  includes a voltage clamping circuit, a voltage division circuit, capacitors  663  and  670 , resistor  669 , and a diode  672 , for entering a protection state when a current and/or voltage of the LED module is/are or might be excessively high, thus preventing damaging of the LED module. The voltage clamping circuit includes a bidirectional triode thyristor (TRIAC)  661  and a DIAC or symmetrical trigger diode  662 . The voltage division circuit includes bipolar junction transistors (BJT)  667  and  668  and resistors  664 ,  665 ,  666 , and  671 . 
     Bidirectional triode thyristor  661  has a first terminal connected to filtering output terminal  521 , a second terminal connected to filtering output terminal  522 , and a control terminal connected to a first terminal of symmetrical trigger diode  662 , which has a second terminal connected to an end of capacitor  663 , which has another end connected to filtering output terminal  522 . Resistor  664  is in parallel to capacitor  663 , and has an end connected to the second terminal of symmetrical trigger diode  662  and another end connected to filtering output terminal  522 . Resistor  665  has an end connected to the second terminal of symmetrical trigger diode  662  and another end connected to the collector terminal of BJT  667 , whose emitter terminal is connected to filtering output terminal  522 . Resistor  666  has an end connected to the second terminal of symmetrical trigger diode  662  and another end connected to the collector terminal of BJT  668  and the base terminal of BJT  667 . The emitter terminal of BJT  668  is connected to filtering output terminal  522 . Resistor  669  has an end connected to the base terminal of BJT  668  and another end connected to an end of capacitor  670 , which has another end connected to filtering output terminal  522 . Resistor  671  has an end connected to the second terminal of symmetrical trigger diode  662  and another end connected to the cathode of diode  672 , whose anode is connected to filtering output terminal  521 . 
     It&#39;s worth noting that according to some embodiments, the resistance of resistor  665  should be smaller than that of resistor  666 . 
     Next, an exemplary operation of protection circuit  660  in overcurrent protection is described as follows. 
     The node connecting resistor  669  and capacitor  670  is to receive a current detection signal S 531 , which represents the magnitude of current through the LED module. The other end of resistor  671  is a voltage terminal  521 ′. In this embodiment concerning overcurrent protection, voltage terminal  521 ′ may be coupled to a biasing voltage source, or be connected through diode  672  to filtering output terminal  521 , as shown in  FIG.  56 B , to take a filtered signal as a biasing voltage source. If voltage terminal  521 ′ is coupled to an external biasing voltage source, diode  672  may be omitted, so it is depicted in a dotted line in  FIG.  56 B . The combination of resistor  669  and capacitor  670  can work to filter out high frequency components of the current detection signal S 531 , and then input the filtered current detection signal S 531  to the base terminal of BJT  668  for controlling current conduction and cutoff of BJT  668 . The filtering function of resistor  669  and capacitor  670  can prevent misoperation of BJT  668  due to noises. In practical use, resistor  669  and capacitor  670  may be omitted, so they are each depicted in a dotted line in  FIG.  56 B . When they are omitted, current detection signal S 531  is input directly to the base terminal of BJT  668 . 
     When the LED lamp is operating normally and the current of the LED module is within a normal range, BJT  668  is in a cutoff state, and resistor  66  works to pull up the base voltage of BJT  667 , which therefore enters a conducting state. In this state, the electric potential at the second terminal of symmetrical trigger diode  662  is determined based on the voltage at voltage terminal  521 ′ of the biasing voltage source and voltage division ratios between resistor  671  and parallel-connected resistors  664  and  665 . Since the resistance of resistor  665  is relatively small, voltage share for resistor  665  is smaller and the electric potential at the second terminal of symmetrical trigger diode  662  is therefore pulled down. Then, the electric potential at the control terminal of bidirectional triode thyristor  661  is in turn pulled down by symmetrical trigger diode  662 , causing bidirectional triode thyristor  661  to enter a cutoff state, which cutoff state makes protection circuit  660  not being in a protection state. 
     When the current of the LED module exceeds an overcurrent value, the level of current detection signal S 531  will increase significantly to cause BJT  668  to enter a conducting state and then pull down the base voltage of BJT  667 , which thereby enters a cutoff state. In this case, the electric potential at the second terminal of symmetrical trigger diode  662  is determined based on the voltage at voltage terminal  521 ′ of the biasing voltage source and voltage division ratios between resistor  671  and parallel-connected resistors  664  and  666 . Since the resistance of resistor  666  is relatively high, voltage share for resistor  666  is larger and the electric potential at the second terminal of symmetrical trigger diode  662  is therefore higher. Then the electric potential at the control terminal of bidirectional triode thyristor  661  is in turn pulled up by symmetrical trigger diode  662 , causing bidirectional triode thyristor  661  to enter a conducting state, which conducting state works to restrain or clamp down on the voltage between filtering output terminals  521  and  522  and thus makes protection circuit  660  being in a protection state. 
     In this embodiment, the voltage at voltage terminal  521 ′ of the biasing voltage source is determined based on the trigger voltage of bidirectional triode thyristor  661 , and voltage division ratio between resistor  671  and parallel-connected resistors  664  and  665 , or voltage division ratio between resistor  671  and parallel-connected resistors  664  and  666 . Through voltage division between resistor  671  and parallel-connected resistors  664  and  665 , the voltage from voltage terminal  521 ′ at symmetrical trigger diode  662  will be lower than the trigger voltage of bidirectional triode thyristor  661 . Otherwise, through voltage division between resistor  671  and parallel-connected resistors  664  and  666 , the voltage from voltage terminal  521 ′ at symmetrical trigger diode  662  will be higher than the trigger voltage of bidirectional triode thyristor  661 . For example, in some embodiments, when the current of the LED module exceeds an overcurrent value, the voltage division circuit is adjusted to the voltage division ratio between resistor  671  and parallel-connected resistors  664  and  666 , causing a higher portion of the voltage at voltage terminal  521 ′ to result at symmetrical trigger diode  662 , achieving a hysteresis function. Specifically, BJTs  667  and  668  as switches are respectively connected in series to resistors  665  and  666  which determine the voltage division ratios. The voltage division circuit is configured to control turning on which one of BJTs  667  and  668  and leaving the other off for determining the relevant voltage division ratio, according to whether the current of the LED module exceeds an overcurrent value. And the clamping circuit determines whether to restrain or clamp down on the voltage of the LED module according to the applying voltage division ratio. 
     Next, an exemplary operation of protection circuit  660  in overvoltage protection is described as follows. 
     The node connecting resistor  669  and capacitor  670  is to receive a current detection signal S 531 , which represents the magnitude of current through the LED module. As described above, protection circuit  660  still works to provide overcurrent protection. The other end of resistor  671  is a voltage terminal  521 ′. In this embodiment concerning overvoltage protection, voltage terminal  521 ′ is coupled to the positive terminal of the LED module to detect the voltage of the LED module. Taking previously described embodiments for example, in embodiments of  FIGS.  53 A and  53 B , LED driving module  530  does not include driving circuit  1530 , and the voltage terminal  521 ′ would be coupled to filtering output terminal  521 . Whereas in embodiments of  FIGS.  54 A ˜ 54 G, LED driving module  530  includes driving circuit  1530 , and the voltage terminal  521 ′ would be coupled to driving output terminal  1521 . In this embodiment, voltage division ratios between resistor  671  and parallel-connected resistors  664  and  665 , and voltage division ratios between resistor  671  and parallel-connected resistors  664  and  666  will be adjusted according to the voltage at voltage terminal  521 ′, for example, the voltage at driving output terminal  1521  or filtering output terminal  521 . Therefore, normal overcurrent protection can still be provided by protection circuit  660 . 
     In some embodiments, when the LED lamp is operating normally, assuming overcurrent condition does not occur, the electric potential at the second terminal of symmetrical trigger diode  662  is determined based on the voltage at voltage terminal  521 ′ and voltage division ratios between resistor  671  and parallel-connected resistors  664  and  665 , and is insufficient to trigger bidirectional triode thyristor  661 . Then bidirectional triode thyristor  661  is in a cutoff state, making protection circuit  660  not being in a protection state. On the other hand, when the LED module is operating abnormally with the voltage at the positive terminal of the LED module exceeding an overvoltage value, the electric potential at the second terminal of symmetrical trigger diode  662  is sufficiently high to trigger bidirectional triode thyristor  661  when the voltage at the first terminal of symmetrical trigger diode  662  is larger than the trigger voltage of bidirectional triode thyristor  661 . Then bidirectional triode thyristor  661  enters a conducting state, making protection circuit  660  being in a protection state to restrain or clamp down on the level of the filtered signal. 
     As described above, protection circuit  660  provides one or two of the functions of overcurrent protection and overvoltage protection. 
     In some embodiments, protection circuit  660  may further include a zener diode connected to resistor  664  in parallel, which zener diode is used to limit or restrain the voltage across resistor  664 . The breakdown voltage of the zener diode is in some embodiments in the range of about 25˜50 volts, and in some embodiments preferably be about 36 volts. 
     Further, a silicon controlled rectifier may be substituted for bidirectional triode thyristor  661 , without negatively affecting the protection functions. Using a silicon controlled rectifier instead of a bidirectional triode thyristor  661  has a lower voltage drop across itself in conduction than that across bidirectional triode thyristor  661  in conduction. 
     In one embodiment, values of the parameters of protection circuit  660  may be set as follows. Resistance of resistor  669  may be about 10 ohms. Capacitance of capacitor  670  may be about 1 nF. Capacitance of capacitor  633  may be about 10 nF. The (breakover) voltage of symmetrical trigger diode  662  may be in the range of about 26˜36 volts. Resistance of resistor  671  may be in the range of about 300 k˜600 k ohms, and may preferably be, in some embodiments, about 540 k ohms. Resistance of resistor  666  is in some embodiments in the range of about 100 k˜300 k ohms, and may preferably be, in some embodiments, about 220 k ohms. Resistance of resistor  665  is in some embodiments in the range of about 30 k˜100 k ohms, and may preferably be, in some embodiments about 40 k ohms. Resistance of resistor  664  is in some embodiments in the range of about 100 k˜300 k ohms, and may preferably be, in some embodiments about 220 k ohms. 
       FIG.  57 A  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to  FIG.  54 A , the embodiment of  FIG.  57 A  includes rectifying circuits  510  and  540 , a filtering circuit  520 , and an LED driving module  530  including a driving circuit  1530  and an LED module  630 , and further includes a mode switching circuit  580 . Mode switching circuit  580  is coupled to at least one of filtering output terminals  521  and  522  and at least one of driving output terminals  1521  and  1522 , for determining whether to perform a first driving mode or a second driving mode, as according to a frequency of the external driving signal. In the first driving mode, a filtered signal from filtering circuit  520  is input into driving circuit  1530 , while in the second driving mode the filtered signal bypasses at least a component of driving circuit  1530 , making driving circuit  1530  stop working in conducting the filtered signal, allowing the filtered signal to (directly) reach and drive LED module  630 . The bypassed component(s) of driving circuit  1530  may include an inductor or a switch, which when bypassed makes driving circuit  1530  unable to transfer and/or convert power, and then stop working in conducting the filtered signal. If driving circuit  1530  includes a capacitor, the capacitor can still be used to filter out ripples of the filtered signal in order to stabilize the voltage across the LED module. When mode switching circuit  580  determines on performing the first driving mode, allowing the filtered signal to be input to driving circuit  1530 , driving circuit  1530  then transforms the filtered signal into a driving signal for driving LED module  630  to emit light. On the other hand, when mode switching circuit  580  determines on performing the second driving mode, allowing the filtered signal to bypass driving circuit  1530  to reach LED module  630 , filtering circuit  520  becomes in effect a driving circuit for LED module  630 . Then filtering circuit  520  provides the filtered signal as a driving signal for the LED module for driving the LED module to emit light. 
     It&#39;s worth noting that mode switching circuit  580  can determine whether to perform the first driving mode or the second driving mode based on a user&#39;s instruction or a detected signal received by the LED lamp through pins  501 ,  502 ,  503 , and  504 . With the mode switching circuit, the power supply module of the LED lamp can adapt to or perform one of appropriate driving modes corresponding to different application environments or driving systems, thus improving the compatibility of the LED lamp. In some embodiments, rectifying circuit  540  may be omitted, and is thus depicted in a dotted line in  FIG.  57 A . 
       FIG.  57 B  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 B , a mode switching circuit  680  includes a mode switch  681  suitable for use with the driving circuit  1630  in  FIG.  54 C . Referring to  FIGS.  57 B and  54 C , mode switch  681  has three terminals  683 ,  684 , and  685 , wherein terminal  683  is coupled to driving output terminal  1522 , terminal  684  is coupled to filtering output terminal  522 , and terminal  685  is coupled to the inductor  1632  in driving circuit  1630 . 
     When mode switching circuit  680  determines on performing a first driving mode, mode switch  681  conducts current in a first conductive path through terminals  683  and  685  and a second conductive path through terminals  683  and  684  is in a cutoff state. In this case, driving output terminal  1522  is coupled to inductor  1632 , and therefore driving circuit  1630  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  680  determines on performing a second driving mode, mode switch  681  conducts current in the second conductive path through terminals  683  and  684  and the first conductive path through terminals  683  and  685  is in a cutoff state. In this case, driving output terminal  1522  is coupled to filtering output terminal  522 , and therefore driving circuit  1630  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1632  and switch  1635  in driving circuit  1630 . 
       FIG.  57 C  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 C , a mode switching circuit  780  includes a mode switch  781  suitable for use with the driving circuit  1630  in  FIG.  54 C . Referring to  FIGS.  57 C and  54 C , mode switch  781  has three terminals  783 ,  784 , and  785 , wherein terminal  783  is coupled to filtering output terminal  522 , terminal  784  is coupled to driving output terminal  1522 , and terminal  785  is coupled to switch  1635  in driving circuit  1630 . 
     When mode switching circuit  780  determines on performing a first driving mode, mode switch  781  conducts current in a first conductive path through terminals  783  and  785  and a second conductive path through terminals  783  and  784  is in a cutoff state. In this case, filtering output terminal  522  is coupled to switch  1635 , and therefore driving circuit  1630  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  780  determines on performing a second driving mode, mode switch  781  conducts current in the second conductive path through terminals  783  and  784  and the first conductive path through terminals  783  and  785  is in a cutoff state. In this case, driving output terminal  1522  is coupled to filtering output terminal  522 , and therefore driving circuit  1630  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1632  and switch  1635  in driving circuit  1630 . 
       FIG.  57 D  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 D , a mode switching circuit  880  includes a mode switch  881  suitable for use with the driving circuit  1730  in  FIG.  54 D . Referring to  FIGS.  57 D and  54 D , mode switch  881  has three terminals  883 ,  884 , and  885 , wherein terminal  883  is coupled to filtering output terminal  521 , terminal  884  is coupled to driving output terminal  1521 , and terminal  885  is coupled to inductor  1732  in driving circuit  1730 . 
     When mode switching circuit  880  determines on performing a first driving mode, mode switch  881  conducts current in a first conductive path through terminals  883  and  885  and a second conductive path through terminals  883  and  884  is in a cutoff state. In this case, filtering output terminal  521  is coupled to inductor  1732 , and therefore driving circuit  1730  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  880  determines on performing a second driving mode, mode switch  881  conducts current in the second conductive path through terminals  883  and  884  and the first conductive path through terminals  883  and  885  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and therefore driving circuit  1730  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1732  and freewheeling diode  1733  in driving circuit  1730 . 
       FIG.  57 E  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 E , a mode switching circuit  980  includes a mode switch  981  suitable for use with the driving circuit  1730  in  FIG.  54 D . Referring to  FIGS.  57 E and  54 D , mode switch  981  has three terminals  983 ,  984 , and  985 , wherein terminal  983  is coupled to driving output terminal  1521 , terminal  984  is coupled to filtering output terminal  521 , and terminal  985  is coupled to the cathode of diode  1733  in driving circuit  1730 . 
     When mode switching circuit  980  determines on performing a first driving mode, mode switch  981  conducts current in a first conductive path through terminals  983  and  985  and a second conductive path through terminals  983  and  984  is in a cutoff state. In this case, filtering output terminal  521  is coupled to the cathode of diode  1733 , and therefore driving circuit  1730  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  980  determines on performing a second driving mode, mode switch  981  conducts current in the second conductive path through terminals  983  and  984  and the first conductive path through terminals  983  and  985  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and therefore driving circuit  1730  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1732  and freewheeling diode  1733  in driving circuit  1730 . 
       FIG.  57 F  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 F , a mode switching circuit  1680  includes a mode switch  1681  suitable for use with the driving circuit  1830  in  FIG.  54 E . Referring to  FIGS.  57 F and  54 E , mode switch  1681  has three terminals  1683 ,  1684 , and  1685 , wherein terminal  1683  is coupled to filtering output terminal  521 , terminal  1684  is coupled to driving output terminal  1521 , and terminal  1685  is coupled to switch  1835  in driving circuit  1830 . 
     When mode switching circuit  1680  determines on performing a first driving mode, mode switch  1681  conducts current in a first conductive path through terminals  1683  and  1685  and a second conductive path through terminals  1683  and  1684  is in a cutoff state. In this case, filtering output terminal  521  is coupled to switch  1835 , and therefore driving circuit  1830  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  1680  determines on performing a second driving mode, mode switch  1681  conducts current in the second conductive path through terminals  1683  and  1684  and the first conductive path through terminals  1683  and  1685  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and therefore driving circuit  1830  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1832  and switch  1835  in driving circuit  1830 . 
       FIG.  57 G  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 G , a mode switching circuit  1780  includes a mode switch  1781  suitable for use with the driving circuit  1830  in  FIG.  54 E . Referring to  FIGS.  57 G and  54 E , mode switch  1781  has three terminals  1783 ,  1784 , and  1785 , wherein terminal  1783  is coupled to filtering output terminal  521 , terminal  1784  is coupled to driving output terminal  1521 , and terminal  1785  is coupled to inductor  1832  in driving circuit  1830 . 
     When mode switching circuit  1780  determines on performing a first driving mode, mode switch  1781  conducts current in a first conductive path through terminals  1783  and  1785  and a second conductive path through terminals  1783  and  1784  is in a cutoff state. In this case, filtering output terminal  521  is coupled to inductor  1832 , and therefore driving circuit  1830  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  1780  determines on performing a second driving mode, mode switch  1781  conducts current in the second conductive path through terminals  1783  and  1784  and the first conductive path through terminals  1783  and  1785  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and therefore driving circuit  1830  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing inductor  1832  and switch  1835  in driving circuit  1830 . 
       FIG.  57 H  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 H , a mode switching circuit  1880  includes mode switches  1881  and  1882  suitable for use with the driving circuit  1930  in  FIG.  54 F . Referring to  FIGS.  57 H and  54 F , mode switch  1881  has three terminals  1883 ,  1884 , and  1885 , wherein terminal  1883  is coupled to driving output terminal  1521 , terminal  1884  is coupled to filtering output terminal  521 , and terminal  1885  is coupled to freewheeling diode  1933  in driving circuit  1930 . And mode switch  1882  has three terminals  1886 ,  1887 , and  1888 , wherein terminal  1886  is coupled to driving output terminal  1522 , terminal  1887  is coupled to filtering output terminal  522 , and terminal  1888  is coupled to filtering output terminal  521 . 
     When mode switching circuit  1880  determines on performing a first driving mode, mode switch  1881  conducts current in a first conductive path through terminals  1883  and  1885  and a second conductive path through terminals  1883  and  1884  is in a cutoff state, and mode switch  1882  conducts current in a third conductive path through terminals  1886  and  1888  and a fourth conductive path through terminals  1886  and  1887  is in a cutoff state. In this case, driving output terminal  1521  is coupled to freewheeling diode  1933 , and filtering output terminal  521  is coupled to driving output terminal  1522 . Therefore, driving circuit  1930  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  1880  determines on performing a second driving mode, mode switch  1881  conducts current in the second conductive path through terminals  1883  and  1884  and the first conductive path through terminals  1883  and  1885  is in a cutoff state, and mode switch  1882  conducts current in the fourth conductive path through terminals  1886  and  1887  and the third conductive path through terminals  1886  and  1888  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and filtering output terminal  522  is coupled to driving output terminal  1522 . Therefore, driving circuit  1930  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing freewheeling diode  1933  and switch  1935  in driving circuit  1930 . 
       FIG.  57 I  is a schematic diagram of the mode switching circuit in an LED lamp according to an embodiment of the present invention. Referring to  FIG.  57 I , a mode switching circuit  1980  includes mode switches  1981  and  1982  suitable for use with the driving circuit  1930  in  FIG.  54 F . Referring to  FIGS.  57 I and  54 F , mode switch  1981  has three terminals  1983 ,  1984 , and  1985 , wherein terminal  1983  is coupled to filtering output terminal  522 , terminal  1984  is coupled to driving output terminal  1522 , and terminal  1985  is coupled to switch  1935  in driving circuit  1930 . And mode switch  1982  has three terminals  1986 ,  1987 , and  1988 , wherein terminal  1986  is coupled to filtering output terminal  521 , terminal  1987  is coupled to driving output terminal  1521 , and terminal  1988  is coupled to driving output terminal  1522 . 
     When mode switching circuit  1980  determines on performing a first driving mode, mode switch  1981  conducts current in a first conductive path through terminals  1983  and  1985  and a second conductive path through terminals  1983  and  1984  is in a cutoff state, and mode switch  1982  conducts current in a third conductive path through terminals  1986  and  1988  and a fourth conductive path through terminals  1986  and  1987  is in a cutoff state. In this case, driving output terminal  1522  is coupled to filtering output terminal  521 , and filtering output terminal  522  is coupled to switch  1935 . Therefore, driving circuit  1930  is working normally, which working includes receiving a filtered signal from filtering output terminals  521  and  522  and then transforming the filtered signal into a driving signal, output at driving output terminals  1521  and  1522  for driving the LED module. 
     When mode switching circuit  1980  determines on performing a second driving mode, mode switch  1981  conducts current in the second conductive path through terminals  1983  and  1984  and the first conductive path through terminals  1983  and  1985  is in a cutoff state, and mode switch  1982  conducts current in the fourth conductive path through terminals  1986  and  1987  and the third conductive path through terminals  1986  and  1988  is in a cutoff state. In this case, driving output terminal  1521  is coupled to filtering output terminal  521 , and filtering output terminal  522  is coupled to driving output terminal  1522 . Therefore, driving circuit  1930  stops working, and a filtered signal is input through filtering output terminals  521  and  522  to driving output terminals  1521  and  1522  for driving the LED module, while bypassing freewheeling diode  1933  and switch  1935  in driving circuit  1930 . 
     It&#39;s worth noting that the mode switches in the above embodiments may each comprise, for example, a single-pole double-throw switch, or comprise two semiconductor switches (such as metal oxide semiconductor transistors), for switching a conductive path on to conduct current while leaving the other conductive path cutoff. Each of the two conductive paths provides a path for conducting the filtered signal, allowing the current of the filtered signal to flow through one of the two paths, thereby achieving the function of mode switching or selection. For example, with reference to  FIGS.  49 A,  49 B, and  49 D  in addition, when the lamp driving circuit  505  is not present and the LED tube lamp  500  is directly supplied by the AC power supply  508 , the mode switching circuit may determine on performing a first driving mode in which the driving circuit (such as driving circuit  1530 ,  1630 ,  1730 ,  1830 , or  1930 ) transforms the filtered signal into a driving signal of a level meeting a required level to properly drive the LED module to emit light. On the other hand, when the lamp driving circuit  505  is present, the mode switching circuit may determine on performing a second driving mode in which the filtered signal is (almost) directly used to drive the LED module to emit light; or alternatively the mode switching circuit may determine on performing the first driving mode to drive the LED module to emit light. 
       FIG.  58 A  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to  FIG.  49 E , the embodiment of  FIG.  58 A  includes rectifying circuits  510  and  540 , a filtering circuit  520 , and an LED driving module  530 , and further includes a ballast-compatible circuit  1510 . The ballast-compatible circuit  1510  may be coupled between pin  501  and/or pin  502  and rectifying circuit  510 . This embodiment is explained assuming the ballast-compatible circuit  1510  to be coupled between pin  501  and rectifying circuit  510 . With reference to  FIGS.  49 A,  49 B, and  49 D  in addition to  FIG.  58 A , lamp driving circuit  505  comprises a ballast configured to provide an AC driving signal to drive the LED lamp in this embodiment. 
     In an initial stage upon the activation of the driving system of lamp driving circuit  505 , lamp driving circuit  505 &#39;s ability to output relevant signal(s) has not risen to a standard state. However, in the initial stage the power supply module of the LED lamp instantly or rapidly receives or conducts the AC driving signal provided by lamp driving circuit  505 , which initial conduction is likely to fail the starting of the LED lamp by lamp driving circuit  505  as lamp driving circuit  505  is initially loaded by the LED lamp in this stage. For example, internal components of lamp driving circuit  505  may need to retrieve power from a transformed output in lamp driving circuit  505 , in order to maintain their operation upon the activation. In this case, the activation of lamp driving circuit  505  may end up failing as its output voltage could not normally rise to a required level in this initial stage; or the quality factor (Q) of a resonant circuit in lamp driving circuit  505  may vary as a result of the initial loading from the LED lamp, so as to cause the failure of the activation. 
     In this embodiment, in the initial stage upon activation, ballast-compatible circuit  1510  will be in an open-circuit state, preventing the energy of the AC driving signal from reaching the LED module. After a defined delay upon the AC driving signal as an external driving signal being input to the LED tube lamp, ballast-compatible circuit  1510  switches from a cutoff state during the delay to a conducting state, allowing the energy of the AC driving signal to start to reach the LED module. By means of the delayed conduction of ballast-compatible circuit  1510 , operation of the LED lamp simulates the lamp-starting characteristics of a fluorescent lamp, that is, internal gases of the fluorescent lamp will normally discharge for light emission after a delay upon activation of a driving power supply. Therefore, ballast-compatible circuit  1510  further improves the compatibility of the LED lamp with lamp driving circuits  505  such as an electronic ballast. 
     In this embodiment, rectifying circuit  540  may be omitted and is therefore depicted by a dotted line in  FIG.  58 A . 
       FIG.  58 B  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to  FIG.  58 A , ballast-compatible circuit  1510  in the embodiment of  FIG.  58 B  is coupled between pin  503  and/or pin  504  and rectifying circuit  540 . As explained regarding ballast-compatible circuit  1510  in  FIG.  58 A , ballast-compatible circuit  1510  in  FIG.  58 B  performs the function of delaying the starting of the LED lamp, or causing the input of the AC driving signal to be delayed for a predefined time, in order to prevent the failure of starting by lamp driving circuits  505  such as an electronic ballast. 
     Apart from coupling ballast-compatible circuit  1510  between terminal pin(s) and rectifying circuit in the above embodiments, ballast-compatible circuit  1510  may alternatively be included within a rectifying circuit with a different structure.  FIG.  58 C  illustrates an arrangement with a ballast-compatible circuit in an LED lamp according to a preferred embodiment of the present invention. Referring to  FIG.  58 C , the rectifying circuit assumes the circuit structure of rectifying circuit  810  in  FIG.  50 C . Rectifying circuit  810  includes rectifying unit  815  and terminal adapter circuit  541 . Rectifying unit  815  is coupled to pins  501  and  502 , terminal adapter circuit  541  is coupled to filtering output terminals  511  and  512 , and the ballast-compatible circuit  1510  in  FIG.  58 C  is coupled between rectifying unit  815  and terminal adapter circuit  541 . In this case, in the initial stage upon activation of the ballast, an AC driving signal as an external driving signal is input to the LED tube lamp, where the AC driving signal can only reach rectifying unit  815 , but cannot reach other circuits such as terminal adapter circuit  541 , other internal filter circuitry, and the LED driving module. Moreover, parasitic capacitors associated with rectifying diodes  811  and  812  within rectifying unit  815  are quite small in capacitance and thus can be ignored. Accordingly, lamp driving circuit  505  in the initial stage isn&#39;t loaded with or effectively connected to the equivalent capacitor or inductor of the power supply module of the LED lamp, and the quality factor (Q) of lamp driving circuit  505  is therefore not adversely affected in this stage, resulting in a successful starting of the LED lamp by lamp driving circuit  505 . 
     It&#39;s worth noting that under the condition that terminal adapter circuit  541  does not include components such as capacitors or inductors, interchanging rectifying unit  815  and terminal adapter circuit  541  in position, meaning rectifying unit  815  is connected to filtering output terminals  511  and  512  and terminal adapter circuit  541  is connected to pins  501  and  502 , does not affect or alter the function of ballast-compatible circuit  1510 . 
     Further, as explained in  FIGS.  50 A   50 D, when a rectifying circuit is connected to pins  503  and  504  instead of pins  501  and  502 , this rectifying circuit may constitute the rectifying circuit  540 . That is, the circuit arrangement with a ballast-compatible circuit  1510  in  FIG.  58 C  may be alternatively included in rectifying circuit  540  instead of rectifying circuit  810 , without affecting the function of ballast-compatible circuit  1510 . 
     In some embodiments, as described above terminal adapter circuit  541  does not include components such as capacitors or inductors. Or when rectifying circuit  610  in  FIG.  50 A  constitutes the rectifying circuit  510  or  540 , parasitic capacitances in the rectifying circuit  510  or  540  are quite small and thus can be ignored. These conditions contribute to not affecting the quality factor of lamp driving circuit  505 . 
       FIG.  58 D  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to the embodiment of  FIG.  58 A , ballast-compatible circuit  1510  in the embodiment of  FIG.  58 D  is coupled between rectifying circuit  540  and filtering circuit  520 . Since rectifying circuit  540  also does not include components such as capacitors or inductors, the function of ballast-compatible circuit  1510  in the embodiment of  FIG.  58 D  will not be affected. 
       FIG.  58 E  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to the embodiment of  FIG.  58 A , ballast-compatible circuit  1510  in the embodiment of  FIG.  58 E  is coupled between rectifying circuit  510  and filtering circuit  520 . Similarly, since rectifying circuit  510  does not include components such as capacitors or inductors, the function of ballast-compatible circuit  1510  in the embodiment of  FIG.  58 E  will not be affected. 
       FIG.  58 F  is a schematic diagram of the ballast-compatible circuit according to an embodiment of the present invention. Referring to  FIG.  58 F , a ballast-compatible circuit  1610  has an initial state in which an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals  1611  and  1621 . Upon receiving an input signal at ballast-compatible circuit input terminal  1611 , a delay will pass until a current conduction occurs through and between ballast-compatible circuit input and output terminals  1611  and  1621 , transmitting the input signal to ballast-compatible circuit output terminal  1621 . 
     Ballast-compatible circuit  1610  includes a diode  1612 , resistors  1613 ,  1615 ,  1618 ,  1620 , and  1622 , a bidirectional triode thyristor (TRIAC)  1614 , a DIAC or symmetrical trigger diode  1617 , a capacitor  1619 , and ballast-compatible circuit input and output terminals  1611  and  1621 . It&#39;s noted that the resistance of resistor  1613  should be quite large so that when bidirectional triode thyristor  1614  is cutoff in an open-circuit state, an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals  1611  and  1621 . 
     Bidirectional triode thyristor  1614  is coupled between ballast-compatible circuit input and output terminals  1611  and  1621 , and resistor  1613  is also coupled between ballast-compatible circuit input and output terminals  1611  and  1621  and in parallel to bidirectional triode thyristor  1614 . Diode  1612 , resistors  1620  and  1622 , and capacitor  1619  are series-connected in sequence between ballast-compatible circuit input and output terminals  1611  and  1621 , and are connected in parallel to bidirectional triode thyristor  1614 . Diode  1612  has an anode connected to bidirectional triode thyristor  1614 , and has a cathode connected to an end of resistor  1620 . Bidirectional triode thyristor  1614  has a control terminal connected to a terminal of symmetrical trigger diode  1617 , which has another terminal connected to an end of resistor  1618 , which has another end connected to a node connecting capacitor  1619  and resistor  1622 . Resistor  1615  is connected between the control terminal of bidirectional triode thyristor  1614  and a node connecting resistor  1613  and capacitor  1619 . 
     When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input to ballast-compatible circuit input terminal  1611 , bidirectional triode thyristor  1614  will be in an open-circuit state, not allowing the AC driving signal to pass through and the LED lamp is therefore also in an open-circuit state. In this state, the AC driving signal is charging capacitor  1619  through diode  1612  and resistors  1620  and  1622 , gradually increasing the voltage of capacitor  1619 . Upon continually charging for a period of time, the voltage of capacitor  1619  increases to be above the trigger voltage value of symmetrical trigger diode  1617  so that symmetrical trigger diode  1617  is turned on in a conducting state. Then the conducting symmetrical trigger diode  1617  will in turn trigger bidirectional triode thyristor  1614  on in a conducting state. In this situation, the conducting bidirectional triode thyristor  1614  electrically connects ballast-compatible circuit input and output terminals  1611  and  1621 , allowing the AC driving signal to flow through ballast-compatible circuit input and output terminals  1611  and  1621 , thus starting the operation of the power supply module of the LED lamp. In this case the energy stored by capacitor  1619  will maintain the conducting state of bidirectional triode thyristor  1614 , to prevent the AC variation of the AC driving signal from causing bidirectional triode thyristor  1614  and therefore ballast-compatible circuit  1610  to be cutoff again, or to prevent the problem of bidirectional triode thyristor  1614  alternating or switching between its conducting and cutoff states. 
     In general, in hundreds of milliseconds upon activation of a lamp driving circuit  505  such as an electronic ballast, the output voltage of the ballast has risen above a certain voltage value as the output voltage hasn&#39;t been adversely affected by the sudden initial loading from the LED lamp. A detection mechanism to detect whether lighting of a fluorescent lamp is achieved may be disposed in lamp driving circuits  505  such as an electronic ballast. In this detection mechanism, if a fluorescent lamp fails to be lit up for a defined period of time, an abnormal state of the fluorescent lamp is detected, causing the fluorescent lamp to enter a protection state. In view of these facts, in certain embodiments, the delay provided by ballast-compatible circuit  1610  until conduction of ballast-compatible circuit  1610  and then the LED lamp should be and may preferably be in the range of about 0.1˜3 seconds. 
     It&#39;s worth noting that an additional capacitor  1623  may be coupled in parallel to resistor  1622 . Capacitor  1623  works to reflect or support instantaneous change in the voltage between ballast-compatible circuit input and output terminals  1611  and  1621 , and will not affect the function of delayed conduction performed by ballast-compatible circuit  1610 . 
       FIG.  58 G  is a block diagram of a power supply module in an LED lamp according to an embodiment of the present invention. Compared to the embodiment of  FIG.  49 D , lamp driving circuit  505  in the embodiment of  FIG.  58 G  drives a plurality of LED tube lamps  500  connected in series, wherein a ballast-compatible circuit  1610  is disposed in each of the LED tube lamps  500 . For the convenience of illustration, two series-connected LED tube lamps  500  are assumed for example and explained as follows. 
     Because the two ballast-compatible circuits  1610  respectively of the two LED tube lamps  500  can actually have different delays until conduction of the LED tube lamps  500 , due to various factors such as errors occurring in production processes of some components, the actual timing of conduction of each of the ballast-compatible circuits  1610  is different. Upon activation of a lamp driving circuit  505 , the voltage of the AC driving signal provided by lamp driving circuit  505  will be shared out by the two LED tube lamps  500  roughly equally. Subsequently when only one of the two LED tube lamps  500  first enters a conducting state, the voltage of the AC driving signal then will be borne mostly or entirely by the other LED tube lamp  500 . This situation will cause the voltage across the ballast-compatible circuits  1610  in the other LED tube lamp  500  that is not conducting to suddenly increase or be doubled, meaning the voltage between ballast-compatible circuit input and output terminals  1611  and  1621  might even be suddenly doubled. In view of this, if capacitor  1623  is included, the voltage division effect between capacitors  1619  and  1623  will instantaneously increase the voltage of capacitor  1619 , making symmetrical trigger diode  1617  triggering bidirectional triode thyristor  1614  into a conducting state, thus causing the two ballast-compatible circuits  1610  respectively of the two LED tube lamps  500  to become conducting almost at the same time. Therefore, by introducing capacitor  1623 , the situation, where one of the two ballast-compatible circuits  1610  respectively of the two series-connected LED tube lamps  500  that is first conducting has its bidirectional triode thyristor  1614  then suddenly cutoff as having insufficient current passing through due to the discrepancy between the delays provided by the two ballast-compatible circuits  1610  until their respective conductions, can be avoided. Therefore, using each ballast-compatible circuit  1610  with capacitor  1623  further improves the compatibility of the series-connected LED tube lamps with each of lamp driving circuits  505  such as an electronic ballast. 
     In practical use, a suggested range of the capacitance of capacitor  1623  is about 10 pF to about 1 nF, which may preferably be in the range of about 10 pF to about 100 pF, and may be even more desirable at about 47 pF. 
     It&#39;s worth noting that diode  1612  is used or configured to rectify the signal for charging capacitor  1619 . Therefore, with reference to  FIGS.  58 C,  58 D, and  58 E , in the case when ballast-compatible circuit  1610  is arranged following a rectifying unit or circuit, diode  1612  may be omitted. Thus diode  1612  is depicted in a dotted line in  FIG.  58 F . 
       FIG.  58 H  is a schematic diagram of the ballast-compatible circuit according to another embodiment of the present invention. Referring to  FIG.  58 H , a ballast-compatible circuit  1710  has an initial state in which an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals  1711  and  1721 . Upon receiving an input signal at ballast-compatible circuit input terminal  1711 , ballast-compatible circuit  1710  will be in a cutoff state when the level of the input external driving signal is below a defined value corresponding to a conduction delay of ballast-compatible circuit  1710 ; and ballast-compatible circuit  1710  will enter a conducting state upon the level of the input external driving signal reaching the defined value, thus transmitting the input signal to ballast-compatible circuit output terminal  1721 . 
     Ballast-compatible circuit  1710  includes a bidirectional triode thyristor (TRIAC)  1712 , a DIAC or symmetrical trigger diode  1713 , resistors  1714 ,  1716 , and  1717 , and a capacitor  1715 . Bidirectional triode thyristor  1712  has a first terminal connected to ballast-compatible circuit input terminal  1711 ; a control terminal connected to a terminal of symmetrical trigger diode  1713  and an end of resistor  1714 ; and a second terminal connected to another end of resistor  1714 . Capacitor  1715  has an end connected to another terminal of symmetrical trigger diode  1713 , and has another end connected to the second terminal of bidirectional triode thyristor  1712 . Resistor  1717  is in parallel connection with capacitor  1715 , and is therefore also connected to said another terminal of symmetrical trigger diode  1713  and the second terminal of bidirectional triode thyristor  1712 . And resistor  1716  has an end connected to the node connecting capacitor  1715  and symmetrical trigger diode  1713 , and has another end connected to ballast-compatible circuit output terminal  1721 . 
     When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input to ballast-compatible circuit input terminal  1711 , bidirectional triode thyristor  1712  will be in an open-circuit state, not allowing the AC driving signal to pass through and the LED lamp is therefore also in an open-circuit state. The input of the AC driving signal causes a potential difference between ballast-compatible circuit input terminal  1711  and ballast-compatible circuit output terminal  1721 . When the AC driving signal increases with time to eventually reach a sufficient amplitude (which is a defined level after the delay) after a period of time, the signal level at ballast-compatible circuit output terminal  1721  has a reflected voltage at the control terminal of bidirectional triode thyristor  1712  after passing through resistor  1716 , parallel-connected capacitor  1715  and resistor  1717 , and resistor  1714 , wherein the reflected voltage then triggers bidirectional triode thyristor  1712  into a conducting state. This conducting state makes ballast-compatible circuit  1710  entering a conducting state which causes the LED lamp to operate normally. Upon bidirectional triode thyristor  1712  conducting, a current flows through resistor  1716  and then charges capacitor  1715  to store a specific voltage on capacitor  1715 . In this case, the energy stored by capacitor  1715  will maintain the conducting state of bidirectional triode thyristor  1712 , to prevent the AC variation of the AC driving signal from causing bidirectional triode thyristor  1712  and therefore ballast-compatible circuit  1710  to be cutoff again, or to prevent the situation of bidirectional triode thyristor  1712  alternating or switching between its conducting and cutoff states. 
       FIG.  58 I  illustrates the ballast-compatible circuit according to an embodiment of the present invention. Referring to  FIG.  58 I , a ballast-compatible circuit  1810  includes a housing  1812 , a metallic electrode  1813 , a bimetallic strip  1814 , and a heating filament  1816 . Metallic electrode  1813  and heating filament  1816  protrude from the housing  1812 , so that they each have a portion inside the housing  1812  and a portion outside of the housing  1812 . Metallic electrode  1813 &#39;s outside portion has a ballast-compatible circuit input terminal  1811 , and heating filament  1816 &#39;s outside portion has a ballast-compatible circuit output terminal  1821 . Housing  1812  is hermetic or tightly sealed and contains inertial gas  1815  such as helium gas. Bimetallic strip  1814  is inside housing  1812  and is physically and electrically connected to the portion of heating filament  1816  that is inside the housing  1812 . And there is a spacing between bimetallic strip  1814  and metallic electrode  1813 , so that ballast-compatible circuit input terminal  1811  and ballast-compatible circuit output terminal  1821  are not electrically connected in the initial state of ballast-compatible circuit  1810 . Bimetallic strip  1814  may include two metallic strips with different temperature coefficients, wherein the metallic strip closer to metallic electrode  1813  has a smaller temperature coefficient, and the metallic strip more away from metallic electrode  1813  has a larger temperature coefficient. 
     When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input at ballast-compatible circuit input terminal  1811  and ballast-compatible circuit output terminal  1821 , a potential difference between metallic electrode  1813  and heating filament  1816  is formed. When the potential difference increases enough to cause electric arc or arc discharge through inertial gas  1815 , meaning when the AC driving signal increases with time to eventually reach the defined level after a delay, then inertial gas  1815  is then heated to cause bimetallic strip  1814  to swell toward metallic electrode  1813  (as in the direction of the broken-line arrow in  FIG.  58 I ), with this swelling eventually causing bimetallic strip  1814  to bear against metallic electrode  1813 , forming the physical and electrical connections between them. In this situation, there is electrical conduction between ballast-compatible circuit input terminal  1811  and ballast-compatible circuit output terminal  1821 . Then the AC driving signal flows through and thus heats heating filament  1816 . In this heating process, heating filament  1816  allows a current to flow through when electrical conduction exists between metallic electrode  1813  and bimetallic strip  1814 , causing the temperature of bimetallic strip  1814  to be above a defined conduction temperature. As a result, since the respective temperature of the two metallic strips of bimetallic strip  1814  with different temperature coefficients are maintained above the defined conduction temperature, bimetallic strip  1814  will bend against or toward metallic electrode  1813 , thus maintaining or supporting the physical joining or connection between bimetallic strip  1814  and metallic electrode  1813 . 
     Therefore, upon receiving an input signal at ballast-compatible circuit input and output terminals  1811  and  1821 , a delay will pass until an electrical/current conduction occurs through and between ballast-compatible circuit input and output terminals  1811  and  1821 . 
     Therefore, an exemplary ballast-compatible circuit such as described herein may be coupled between any pin and any rectifying circuit described above in the invention, wherein the ballast-compatible circuit will be in a cutoff state in a defined delay upon an external driving signal being input to the LED tube lamp, and will enter a conducting state after the delay. Otherwise, the ballast-compatible circuit will be in a cutoff state when the level of the input external driving signal is below a defined value corresponding to a conduction delay of the ballast-compatible circuit; and ballast-compatible circuit will enter a conducting state upon the level of the input external driving signal reaching the defined value. Accordingly, the compatibility of the LED tube lamp described herein with lamp driving circuits  505  such as an electronic ballast is further improved by using such a ballast-compatible circuit. 
       FIG.  59 A  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  49 E , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , and the LED driving module  530 , and further comprises two ballast-compatible circuits  1540 . The two ballast-compatible circuits  1540  are coupled respectively between the pin  503  and the rectifying output terminal  511  and between the pin  504  and the rectifying output terminal  511 . Referring to  FIG.  49 A ,  FIG.  49 B  and  FIG.  49 D , the lamp driving circuit  505  is an electronic ballast for supplying an AC driving signal to drive the LED lamp of the present invention. 
     Two ballast-compatible circuits  1540  are initially in conducting states, and then enter into cutoff states in a delay. Therefore, in an initial stage upon activation of the lamp driving circuit  505 , the AC driving signal is transmitted through the pin  503 , the corresponding ballast-compatible circuit  1540 , the rectifying output terminal  511  and the rectifying circuit  510 , or through the pin  504 , the corresponding ballast-compatible circuit  1540 , the rectifying output terminal  511  and the rectifying circuit  510  of the LED lamp, and the filtering circuit  520  and LED driving module  530  of the LED lamp are bypassed. Thereby, the LED lamp presents almost no load and does not affect the quality factor of the lamp driving circuit  505  at the beginning, and so the lamp driving circuit can be activated successfully. The two ballast-compatible circuits  1540  are cut off after a time period while the lamp driving circuit  505  has been activated successfully. After that, the lamp driving circuit  505  has a sufficient drive capability for driving the LED lamp to emit light. 
       FIG.  59 B  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  59 A , the two ballast-compatible circuits  1540  are changed to be coupled respectively between the pin  503  and the rectifying output terminal  512  and between the pin  504  and the rectifying output terminal  512 . Similarly, two ballast-compatible circuits  1540  are initially in conducting states, and then changed to cutoff states after an objective delay. Thereby, the lamp driving circuit  505  drives the LED lamp to emit light after the lamp driving circuit  505  has activated. 
     It is worth noting that the arrangement of the two ballast-compatible circuits  1540  may be changed to be coupled between the pin  501  and the rectifying terminal  511  and between the pin  501  and the rectifying terminal  511 , or between the pin  501  and the rectifying terminal  512  and between the pin  501  and the rectifying terminal  512 , for having the lamp driving circuit  505  drive the LED lamp to emit light after being activated. 
       FIG.  59 C  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIGS.  59 A and  59 B , the rectifying circuit  810  shown in  FIG.  50 C  replaces the rectifying circuit  540 , and the rectifying unit  815  of the rectifying circuit  810  is coupled to the pins  503  and  504  and the terminal adapter circuit  541  thereof is coupled to the rectifying output terminals  511  and  512 . The arrangement of the two ballast-compatible circuits  1540  is also changed to be coupled respectively between the pin  501  and the half-wave node  819  and between the pin  502  and the half-wave node  819 . 
     In an initial stage upon activation of the lamp driving circuit  505 , two ballast-compatible circuits  1540  are initially in conducting states. At this moment, the AC driving signal is transmitted through the pin  501 , the corresponding ballast-compatible circuit  1540 , the half-wave node  819  and the rectifying unit  815  or the pin  502 , the corresponding ballast-compatible circuit  1540 , the half-wave node  819  and the rectifying unit  815  of the LED lamp, and the terminal adapter circuit  541 , the filtering circuit  520  and LED driving module  530  of the LED lamp are bypassed. Thereby, the LED lamp presents almost no load and does not affect the quality factor of the lamp driving circuit  505  at the beginning, and so the lamp driving circuit can be activated successfully. The two ballast-compatible circuits  1540  are cut off after a time period while the lamp driving circuit  505  has been activated successfully. After that, the lamp driving circuit  505  has a sufficient drive capability for driving the LED lamp to emit light. 
     It is worth noting that the rectifying circuit  810  shown in  FIG.  50 C  may replace the rectifying circuit  510  of the present embodiment shown in  FIG.  59 C  instead of the rectifying circuit  540 . Wherein, the rectifying unit  815  of the rectifying circuit  810  is coupled to the pins  501  and  502  and the terminal adapter circuit  541  thereof is coupled to the rectifying output terminals  511  and  512 . The arrangement of the two ballast-compatible circuits  1540  is also changed to be coupled respectively between the pin  503  and the half-wave node  819  and between the pin  504  and the half-wave node  819 . 
       FIG.  59 D  is a schematic diagram of a ballast-compatible circuit according to an embodiment of the present invention, which is applicable to the embodiments shown in  FIGS.  59 A and  59 B  and the described modification thereof. 
     A ballast-compatible circuit  1640  comprises resistors  1643 ,  1645 ,  1648  and  1650 , capacitors  1644  and  1649 , diodes  1647  and  1652 , bipolar junction transistors (BJT)  1646  and  1651 , a ballast-compatible circuit terminal  1641  and a ballast-compatible circuit terminal  1642 . One end of the resistor  1645  is coupled to the ballast-compatible circuit terminal  1641 , and the other end is coupled to an emitter of the BJT  1646 . A collector of the BJT  1646  is coupled to a positive end of the diode  1647 , and a negative end thereof is coupled to the ballast-compatible circuit terminal  1642 . The resistor  1643  and the capacitor  1644  are connected in series with each other and coupled between the emitter and the collector of the BJT  1646 , and the connection node of the resistor  1643  and the capacitor  1644  is coupled to a base of the BJT  1646 . One end of the resistor  1650  is coupled to the ballast-compatible circuit terminal  1642 , and the other end is coupled to an emitter of the BJT  1651 . A collector of the BJT  1651  is coupled to a positive end of the diode  1652 , and a negative end thereof is coupled to the ballast-compatible circuit terminal  1641 . The resistor  1648  and the capacitor  1649  are connected in series with each other and coupled between the emitter and the collector of the BJT  1651 , and the connection node of the resistor  1648  and the capacitor  1649  is coupled to a base of the BJT  1651 . 
     In an initial stage upon the lamp driving circuit  505 , e.g. electronic ballast, being activated, voltages across the capacitors  1644  and  1649  are about zero. At this time, the BJTs  1646  and  1651  are in conducting state and the bases thereof allow currents to flow through. Therefore, in an initial stage upon activation of the lamp driving circuit  505 , the ballast-compatible circuits  1640  are in conducting state. The AC driving signal charges the capacitor  1644  through the resistor  1643  and the diode  1647 , and charges the capacitor  1649  through the resistor  1648  and the diode  1652 . After a time period, the voltages across the capacitors  1644  and  1649  reach certain voltages so as to reduce the voltages of the resistors  1643  and  1648 , thereby cutting off the BJTs  1646  and  1651 , i.e., the states of the BJTs  1646  and  1651  are cutoff states. At this time, the state of the ballast-compatible circuit  1640  is changed to the cutoff state. Thereby, the internal capacitor(s) and inductor(s) do not affect in Q-factor of the lamp driving circuit  505  at the beginning for ensuring the lamp driving circuit activating. Hence, the ballast-compatible circuit  1640  improves the compatibility of LED lamp with the electronic ballast. 
     In summary, the two ballast-compatible circuits of the present invention are respectively coupled between a connection node of the rectifying circuit and the filtering circuit (i.e., the rectifying output terminal  511  or  512 ) and the pin  501  and between the connection node and the pin  502 , or coupled between the connection node and the pin  503  and the connection node and the pin  504 . The two ballast-compatible circuits conduct for an objective delay upon the external driving signal being input into the LED tube lamp, and then are cut off for enhancing the compatibility of the LED lamp with the electronic ballast. 
       FIG.  60 A  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  49 E , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , and the LED driving module  530 , and further comprises two filament-simulating circuits  1560 . The filament-simulating circuits  1560  are respectively coupled between the pins  501  and  502  and coupled between the pins  503  and  504 , for improving a compatibility with a lamp driving circuit having filament detection function, e.g.: program-start ballast. 
     In an initial stage upon the lamp driving circuit having filament detection function being activated, the lamp driving circuit will determine whether the filaments of the lamp operate normally or are in an abnormal condition of short-circuit or open-circuit. When determining the abnormal condition of the filaments, the lamp driving circuit stops operating and enters a protection state. In order to avoid that the lamp driving circuit erroneously determines the LED tube lamp to be abnormal due to the LED tube lamp having no filament, the two filament-simulating circuits  1560  simulate the operation of actual filaments of a fluorescent tube to have the lamp driving circuit enter into a normal state to start the LED lamp normally. 
       FIG.  60 B  is a schematic diagram of a filament-simulating circuit according to an embodiment of the present invention. The filament-simulating circuit comprises a capacitor  1663  and a resistor  1665  connected in parallel, and two ends of the capacitor  1663  and two ends of the resistor  1665  are re respectively coupled to filament simulating terminals  1661  and  1662 . Referring to  FIG.  60 A , the filament simulating terminals  1661  and  1662  of the two filament simulating  1660  are respectively coupled to the pins  501  and  502  and the pins  503  and  504 . During the filament detection process, the lamp driving circuit outputs a detection signal to detect the state of the filaments. The detection signal passes the capacitor  1663  and the resistor  1665  and so the lamp driving circuit determines that the filaments of the LED lamp are normal. 
     In addition, a capacitance value of the capacitor  1663  is low and so a capacitive reactance (equivalent impedance) of the capacitor  1663  is far lower than an impedance of the resistor  1665  due to the lamp driving circuit outputting a high-frequency alternative current (AC) signal to drive LED lamp. Therefore, the filament-simulating circuit  1660  consumes fairly low power when the LED lamp operates normally, and so it almost does not affect the luminous efficiency of the LED lamp. 
       FIG.  60 C  is a schematic block diagram including a filament-simulating circuit according to an embodiment of the present invention. In the present embodiment, the filament-simulating circuit  1660  replaces the terminal adapter circuit  541  of the rectifying circuit  810  shown in  FIG.  50 C , which is adopted as the rectifying circuit  510  or/and  540  in the LED lamp. For example, the filament-simulating circuit  1660  of the present embodiment has both of filament simulating and terminal adapting functions. Referring to  FIG.  60 A , the filament simulating terminals  1661  and  1662  of the filament-simulating circuit  1660  are respectively coupled to the pins  501  and  502  or/and pins  503  and  504 . The half-wave node  819  of rectifying unit  815  in the rectifying circuit  810  is coupled to the filament simulating terminal  1662 . 
       FIG.  60 D  is a schematic block diagram including a filament-simulating circuit according to another embodiment of the present invention. Compared to that shown in  FIG.  60 C , the half-wave node is changed to be coupled to the filament simulating terminal  1661 , and the filament-simulating circuit  1660  in the present embodiment still has both of filament simulating and terminal adapting functions. 
       FIG.  60 E  is a schematic diagram of a filament-simulating circuit according to another embodiment of the present invention. A filament-simulating circuit  1760  comprises capacitors  1763  and  1764 , and the resistors  1765  and  1766 . The capacitors  1763  and  1764  are connected in series and coupled between the filament simulating terminals  1661  and  1662 . The resistors  1765  and  1766  are connected in series and coupled between the filament simulating terminals  1661  and  1662 . Furthermore, the connection node of capacitors  1763  and  1764  is coupled to that of the resistors  1765  and  1766 . Referring to  FIG.  60 A , the filament simulating terminals  1661  and  1662  of the filament-simulating circuit  1760  are respectively coupled to the pins  501  and  502  and the pins  503  and  504 . When the lamp driving circuit outputs the detection signal for detecting the state of the filament, the detection signal passes the capacitors  1763  and  1764  and the resistors  1765  and  1766  so that the lamp driving circuit determines that the filaments of the LED lamp are normal. 
     It is worth noting that in some embodiments, capacitance values of the capacitors  1763  and  1764  are low and so a capacitive reactance of the serially connected capacitors  1763  and  1764  is far lower than an impedance of the serially connected resistors  1765  and  1766  due to the lamp driving circuit outputting the high-frequency AC signal to drive LED lamp. Therefore, the filament-simulating circuit  1760  consumes fairly low power when the LED lamp operates normally, and so it almost does not affect the luminous efficiency of the LED lamp. Moreover, any one of the capacitor  1763  and the resistor  1765  is short circuited or is an open circuit, or any one of the capacitor  1764  and the resistor  1766  is short circuited or is an open circuit, the detection signal still passes through the filament-simulating circuit  1760  between the filament simulating terminals  1661  and  1662 . Therefore, the filament-simulating circuit  1760  still operates normally when any one of the capacitor  1763  and the resistor  1765  is short circuited or is an open circuit or any one of the capacitor  1764  and the resistor  1766  is short circuited or is an open circuit, and so it has quite high fault tolerance. 
       FIG.  60 F  is a schematic block diagram including a filament-simulating circuit according to an embodiment of the present invention. In the present embodiment, the filament-simulating circuit  1860  replaces the terminal adapter circuit  541  of the rectifying circuit  810  shown in  FIG.  50 C , which is adopted as the rectifying circuit  510  or/and  540  in the LED lamp. For example, the filament-simulating circuit  1860  of the present embodiment has both of filament simulating and terminal adapting functions. An impedance of the filament-simulating circuit  1860  has a negative temperature coefficient (NTC), i.e., the impedance at a higher temperature is lower than that at a lower temperature. In the present embodiment, the filament-simulating circuit  1860  comprises two NTC resistors  1863  and  1864  connected in series and coupled to the filament simulating terminals  1661  and  1662 . Referring to  FIG.  60 A , the filament simulating terminals  1661  and  1662  are respectively coupled to the pins  501  and  502  or/and the pins  503  and  504 . The half-wave node  819  of the rectifying unit  815  in the rectifying circuit  810  is coupled to a connection node of the NTC resistors  1863  and  1864 . 
     When the lamp driving circuit outputs the detection signal for detecting the state of the filament, the detection signal passes the NTC resistors  1863  and  1864  so that the lamp driving circuit determines that the filaments of the LED lamp are normal. The impedance of the serially connected NTC resistors  1863  and  1864  is gradually decreased with the gradually increasing of temperature due to the detection signal or a preheat process. When the lamp driving circuit enters into the normal state to start the LED lamp normally, the impedance of the serially connected NTC resistors  1863  and  1864  is decreased to a relative low value and so the power consumption of the filament simulation circuit  1860  is lower. 
     An exemplary impedance of the filament-simulating circuit  1860  can be 10 ohms or more at room temperature (25 degrees Celsius) and may be decreased to a range of about 2-10 ohms when the lamp driving circuit enters into the normal state. It may be preferred that the impedance of the filament-simulating circuit  1860  is decreased to a range of about 3-6 ohms when the lamp driving circuit enters into the normal state. 
       FIG.  61 A  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  49 E , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , and the LED driving module  530 , and further comprises an over voltage protection (OVP) circuit  1570 . The OVP circuit  1570  is coupled to the filtering output terminals  521  and  522  for detecting the filtered signal. The OVP circuit  1570  clamps the level of the filtered signal when determining the level thereof higher than a defined OVP value. Hence, the OVP circuit  1570  protects the LED driving module  530  from damage due to an OVP condition. The rectifying circuit  540  may be omitted and is therefore depicted by a dotted line. 
       FIG.  61 B  is a schematic diagram of an overvoltage protection (OVP) circuit according to an embodiment of the present invention. The OVP circuit  1670  comprises a voltage clamping diode  1671 , such as zener diode, coupled to the filtering output terminals  521  and  522 . The voltage clamping diode  1671  is conducted to clamp a voltage difference at a breakdown voltage when the voltage difference of the filtering output terminals  521  and  522  (i.e., the level of the filtered signal) reaches the breakdown voltage. The breakdown voltage may be preferred in a range of about 40 V to about 100 V, and more preferred in a range of about 55 V to about 75V. 
       FIG.  62 A  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  60 A , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , the LED driving module  530  and the two filament-simulating circuits  1560 , and further comprises a ballast detection circuit  1590 . The ballast detection circuit  1590  may be coupled to any one of the pins  501 ,  502 ,  503  and  504  and a corresponding rectifying circuit of the rectifying circuits  510  and  540 . In the present embodiment, the ballast detection circuit  1590  is coupled between the pin  501  and the rectifying circuit  510 . 
     The ballast detection circuit  1590  detects the AC driving signal or a signal input through the pins  501 ,  502 ,  503  and  504 , and determines whether the input signal is provided by an electric ballast based on the detected result. 
       FIG.  62 B  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  62 A , the rectifying circuit  810  shown in  FIG.  50 C  replaces the rectifying circuit  510 . The ballast detection circuit  1590  is coupled between the rectifying unit  815  and the terminal adapter circuit  541 . One of the rectifying unit  815  and the terminal adapter circuit  541  is coupled to the pines  503  and  504 , and the other one is coupled to the rectifying output terminal  511  and  512 . In the present embodiment, the rectifying unit  815  is coupled to the pins  503  and  504 , and the terminal adapter circuit  541  is coupled to the rectifying output terminal  511  and  512 . Similarly, the ballast detection circuit  1590  detects the signal input through the pins  503  and  504  for determining the input signal whether provided by an electric ballast according to the frequency of the input signal. 
     In addition, the rectifying circuit  810  may replace the rectifying circuit  510  instead of the rectifying circuit  540 , and the ballast detection circuit  1590  is coupled between the rectifying unit  815  and the terminal adapter circuit  541  in the rectifying circuit  510 . 
       FIG.  62 C  is a block diagram of a ballast detection circuit according to an embodiment of the present invention. The ballast detection circuit  1590  comprises a detection circuit  1590   a  and a switch circuit  1590   b . The switch circuit  1590   b  is coupled to switch terminals  1591  and  1592 . The detection circuit  1590   a  is coupled to the detection terminals  1593  and  1594  for detecting a signal transmitted through the detection terminals  1593  and  1594 . Alternatively, the switch terminals  1591  and  1592  serves as the detection terminals and the detection terminals  1593  and  1594  are omitted. For example, in certain embodiments, the switch circuit  1590   b  and the detection circuit  1590   a  are commonly coupled to the switch terminals  1591  and  1592 , and the detection circuit  1590   a  detects a signal transmitted through the switch terminals  1591  and  1592 . Hence, the detection terminals  1593  and  1594  are depicted by dotted lines. 
       FIG.  62 D  is a schematic diagram of a ballast detection circuit according to an embodiment of the present invention. The ballast detection circuit  1690  comprises a detection circuit  1690   a  and a switch circuit  1690   b , and is coupled between the switch terminals  1591  and  1592 . The detection circuit  1690   a  comprises a symmetrical trigger diode  1691 , resistors  1692  and  1696  and capacitors  1693 ,  1697  and  1698 . The switch circuit  1690   b  comprises a TRIAC  1699  and an inductor  1694 . 
     The capacitor  1698  is coupled between the switch terminals  1591  and  1592  for generating a detection voltage in response to a signal transmitted through the switch terminals  1591  and  1592 . When the signal is a high frequency signal, the capacitive reactance of the capacitor  1698  is fairly low and so the detection voltage generated thereby is quite high. The resistor  1692  and the capacitor  1693  are connected in series and coupled between two ends of the capacitor  1698 . The serially connected resistor  1692  and the capacitor  1693  is used to filter the detection signal generated by the capacitor  1698  and generates a filtered detection signal at a connection node thereof. The filter function of the resistor  1692  and the capacitor  1693  is used to filter high frequency noise in the detection signal for preventing the switch circuit  1690   b  from misoperation due to the high frequency noise. The resistor  1696  and the capacitor  1697  are connected in series and coupled between two ends of the capacitor  1693 , and transmit the filtered detection signal to one end of the symmetrical trigger diode  1691 . The serially connected resistor  1696  and capacitor  1697  performs second filtering of the filtered detection signal to enhance the filter effect of the detection circuit  1690   a . Based on requirement for filtering level of different application, the capacitor  1697  may be omitted and the end of the symmetrical trigger diode  1691  is coupled to the connection node of the resistor  1692  and the capacitor  1693  through the resistor  1696 . Alternatively, both of the resistor  1696  and the capacitor  1697  are omitted and the end of the symmetrical trigger diode  1691  is directly coupled to the connection node of the resistor  1692  and the capacitor  1693 . Therefore, the resistor  1696  and the capacitor  1697  are depicted by dotted lines. The other end of the symmetrical trigger diode  1691  is coupled to a control end of the TRIAC  1699  of the switch circuit  1690   b . The symmetrical trigger diode  1691  determines whether to generate a control signal  1695  to trigger the TRIAC  1699  on according to a level of a received signal. A first end of the TRIAC  1699  is coupled to the switch terminal  1591  and a second end thereof is coupled to the switch terminal through the inductor  1694 . The inductor  1694  is used to protect the TRIAC  1699  from damage due to a situation where the signal transmitted into the switch terminals  1591  and  1592  is over a maximum rate of rise of Commutation Voltage, a peak repetitive forward (off-state) voltage or a maximum rate of change of current. 
     When the switch terminals  1591  and  1592  receive a low frequency signal or a DC signal, the detection signal generated by the capacitor  1698  is high enough to make the symmetrical trigger diode  1691  generate the control signal  1695  to trigger the TRIAC  1699  on. At this time, the switch terminals  1591  and  1592  are shorted to bypass the circuit(s) connected in parallel with the switch circuit  1690   b , such as a circuit coupled between the switch terminals  1591  and  1592 , the detection circuit  1690   a  and the capacitor  1698 . 
     In some embodiments, when the switch terminals  1591  and  1592  receive a high frequency AC signal, the detection signal generated by the capacitor  1698  is not high enough to make the symmetrical trigger diode  1691  generate the control signal  1695  to trigger the TRIAC  1699  on. At this time, the TRIAC  1699  is cut off and so the high frequency AC signal is mainly transmitted through external circuit or the detection circuit  1690   a.    
     Hence, the ballast detection circuit  1690  can determine whether the input signal is a high frequency AC signal provided by an electric ballast. If yes, the high frequency AC signal is transmitted through the external circuit or the detection circuit  1690   a ; if no, the input signal is transmitted through the switch circuit  1690   b , bypassing the external circuit and the detection circuit  1690   a.    
     It is worth noting that the capacitor  1698  may be replaced by external capacitor(s), such as at least one capacitor in the terminal adapter circuits shown in  FIG.  51 A-C . Therefore, the capacitor  1698  may be omitted and be therefore depicted by a dotted line. 
       FIG.  62 E  is a schematic diagram of a ballast detection circuit according to an embodiment of the present invention. The ballast detection circuit  1790  comprises a detection circuit  1790   a  and a switch circuit  1790   b . The switch circuit  1790   b  is coupled between the switch terminals  1591  and  1592 . The detection circuit  1790   a  is coupled between the detection terminals  1593  and  1594 . The detection circuit  1790   a  comprises inductors  1791  and  1792  with mutual induction, capacitor  1793  and  1796 , a resistor  1794  and a diode  1797 . The switch circuit  1790   b  comprises a switch  1799 . In the present embodiment, the switch  1799  is a P-type Depletion Mode MOSFET, which is cut off when the gate voltage is higher than a threshold voltage and conducted when the gate voltage is lower than the threshold voltage. 
     The inductor  1792  is coupled between the detection terminals  1593  and  1594  and induces a detection voltage in the inductor  1791  based on a current signal flowing through the detection terminals  1593  and  1594 . The level of the detection voltage is varied with the frequency of the current signal, and may be increased with the increasing of that frequency and reduced with the decreasing of that frequency. 
     In some embodiments, when the signal is a high frequency signal, the inductive reactance of the inductor  1792  is quite high and so the inductor  1791  induces the detection voltage with a quite high level. When the signal is a low frequency signal or a DC signal, the inductive reactance of the inductor  1792  is quite low and so the inductor  1791  induces the detection voltage with a quite high level. One end of the inductor  1791  is grounded. The serially connected capacitor  1793  and resistor  1794  is connected in parallel with the inductor  1791 . The capacitor  1793  and resistor  1794  receive the detection voltage generated by the inductor  1791  and filter a high frequency component of the detection voltage to generate a filtered detection voltage. The filtered detection voltage charges the capacitor  1796  through the diode  1797  to generate a control signal  1795 . Due to the diode  1797  providing a one-way charge for the capacitor  1796 , the level of control signal generated by the capacitor  1796  is the maximum value of the detection voltage. The capacitor  1796  is coupled to the control end of the switch  1799 . First and second ends of the switch  1799  are respectively coupled to the switch terminals  1591  and  1592 . 
     When the signal received by the detection terminal  1593  and  1594  is a low frequency signal or a DC signal, the control signal  1795  generated by the capacitor  1796  is lower than the threshold voltage of the switch  1799  and so the switch  1799  are conducted. At this time, the switch terminals  1591  and  1592  are shorted to bypass the external circuit(s) connected in parallel with the switch circuit  1790   b , such as the least one capacitor in the terminal adapter circuits shown in  FIG.  51 A-c . 
     When the signal received by the detection terminal  1593  and  1594  is a high frequency signal, the control signal  1795  generated by the capacitor  1796  is higher than the threshold voltage of the switch  1799  and so the switch  1799  are cut off. At this time, the high frequency signal is transmitted by the external circuit(s). 
     Hence, the ballast detection circuit  1790  can determine whether the input signal is a high frequency AC signal provided by an electric ballast. If yes, the high frequency AC signal is transmitted through the external circuit(s); if no, the input signal is transmitted through the switch circuit  1790   b , bypassing the external circuit. 
     Next, exemplary embodiments of the conduction (bypass) and cut off (not bypass) operations of the switch circuit in the ballast detection circuit of an LED lamp will be illustrated. For example, the switch terminals  1591  and  1592  are coupled to a capacitor connected in series with the LED lamp, e.g., a signal for driving the LED lamp also flows through the capacitor. The capacitor may be disposed inside the LED lamp to be connected in series with internal circuit(s) or outside the LED lamp to be connected in series with the LED lamp. Referring to  FIG.  49 A,  49 B , or  49 D, the AC power supply  508  provides a low voltage and low frequency AC driving signal as an external driving signal to drive the LED tube lamp  500  while the lamp driving circuit  505  does not exist. At this moment, the switch circuit of the ballast detection circuit is conducted, and so the alternative driving signal is provided to directly drive the internal circuits of the LED tube lamp  500 . When the lamp driving circuit  505  exists, the lamp driving circuit  505  provides a high voltage and high frequency AC driving signal as an external driving signal to drive the LED tube lamp  500 . At this moment, the switch circuit of the ballast detection circuit is cut off, and so the capacitor is connected in series with an equivalent capacitor of the internal circuit(s) of the LED tube lamp for forming a capacitive voltage divider network. Thereby, a division voltage applied in the internal circuit(s) of the LED tube lamp is lower than the high voltage and high frequency AC driving signal, e.g.: the division voltage is in a range of 100-270V, and so no over voltage causes the internal circuit(s) damage. Alternatively, the switch terminals  1591  and  1592  is coupled to the capacitor(s) of the terminal adapter circuit shown in  FIG.  51 A  to  FIG.  51 C  to have the signal flowing through the half-wave node as well as the capacitor(s), e.g., the capacitor  642  in  FIG.  51 A , or the capacitor  842  in  FIG.  51 C . When the high voltage and high frequency AC signal generated by the lamp driving circuit  505  is input, the switch circuit is cut off and so the capacitive voltage divider is performed; and when the low frequency AC signal of the commercial power or the direct current of battery is input, the switch circuit bypasses the capacitor(s). 
     It is worth noting that the switch circuit may have plural switch unit to have two or more switch terminal for being connected in parallel with plural capacitors, (e.g., the capacitors  645  and  645  in  FIG.  51 A , the capacitors  643 ,  645  and  646  in  FIG.  51 A , the capacitors  743  and  744  or/and the capacitors  745  and  746  in  FIG.  50 B , the capacitors  843  and  844  in  FIG.  51 C , the capacitors  845  and  846  in  FIG.  51 C , the capacitors  842 ,  843  and  844  in  FIG.  51 C , the capacitors  842 ,  845  and  846  in  FIG.  51 C , and the capacitors  842 ,  843 ,  844 ,  845  and  846  in  FIG.  51 C ) for bypassing the plural capacitor. 
     In addition, the ballast detection circuit of the present invention can be used in conjunction with the mode switching circuits shown in  FIG.  57 A- 57 I . The switch circuit of the ballast detection circuit is replaced with the mode switching circuit. The detection circuit of the ballast detection circuit is coupled to one of the pins  501 ,  502 ,  503  and  504  for detecting the signal input into the LED lamp through the pins  501 ,  502 ,  503  and  504 . The detection circuit generates a control signal to control the mode switching circuit being at the first mode or the second mode according to whether the signal is a high frequency, low frequency or DC signal, i.e., the frequency of the signal. 
     For example, when the signal is a high frequency signal and higher than a defined mode switch frequency, such as the signal provided by the lamp driving circuit  505 , the control signal generated by the detection circuit makes the mode switching circuit be at the second mode for directly inputting the filtered signal into the LED module. When the signal is a low frequency signal or a direct signal and lower than the defined mode switch frequency, such as the signal provided by the commercial power or the battery, the control signal generated by the detection circuit makes the mode switching circuit be at the first mode for directly inputting the filtered signal into the driving circuit. 
       FIG.  63 A  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  60 A , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , the LED driving module  530 , the two filament-simulating circuits  1560 , and further comprises an auxiliary power module  2510 . The auxiliary power module  2510  is coupled between the filtering output terminal  521  and  522 . The auxiliary power module  2510  detects the filtered signal in the filtering output terminals  521  and  522 , and determines whether providing an auxiliary power to the filtering output terminals  521  and  522  based on the detected result. When the supply of the filtered signal is stopped or a level thereof is insufficient, i.e., when a drive voltage for the LED module is below a defined voltage, the auxiliary power module provides auxiliary power to keep the LED driving module  530  continuing to emit light. The defined voltage is determined according to an auxiliary power voltage of the auxiliary power module  2510 . The rectifying circuit  540  and the filament-simulating circuit  1560  may be omitted and are therefore depicted by dotted lines. 
       FIG.  63 B  is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to that shown in  FIG.  63 A , the present embodiment comprises the rectifying circuits  510  and  540 , the filtering circuit  520 , the LED driving module  530 , the two filament-simulating circuits  1560 , and the LED driving module  530  further comprises the driving circuit  1530  and the LED module  630 . The auxiliary power module  2510  is coupled between the driving output terminals  1521  and  1522 . 
     The auxiliary power module  2510  detects the driving signal in the driving output terminals  1521  and  1522 , and determines whether to provide an auxiliary power to the driving output terminals  1521  and  1522  based on the detected result. When the driving signal is no longer being supplied or a level thereof is insufficient, the auxiliary power module provides the auxiliary power to keep the LED module  630  continuously light. The rectifying circuit  540  and the filament-simulating circuit  1560  may be omitted and are therefore depicted by dotted lines. 
       FIG.  63 C  is a schematic diagram of an auxiliary power module according to an embodiment of the present invention. The auxiliary power module  2610  comprises an energy storage unit  2613  and a voltage detection circuit  2614 . The auxiliary power module further comprises an auxiliary power positive terminal  2611  and an auxiliary power negative terminal  2612  for being respectively coupled to the filtering output terminals  521  and  522  or the driving output terminals  1521  and  1522 . The voltage detection circuit  2614  detects a level of a signal at the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612  to determine whether releasing outward the power of the energy storage unit  2613  through the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612 . 
     In the present embodiment, the energy storage unit  2613  is a battery or a supercapacitor. When a voltage difference of the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612  (the drive voltage for the LED module) is higher than the auxiliary power voltage of the energy storage unit  2613 , the voltage detection circuit  2614  charges the energy storage unit  2613  by the signal in the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612 . When the drive voltage is lower than the auxiliary power voltage, the energy storage unit  2613  releases the stored energy outward through the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612 . 
     The voltage detection circuit  2614  comprises a diode  2615 , a bipolar junction transistor (BJT)  2616  and a resistor  2617 . A positive end of the diode  2615  is coupled to a positive end of the energy storage unit  2613  and a negative end of the diode  2615  is coupled to the auxiliary power positive terminal  2611 . The negative end of the energy storage unit  2613  is coupled to the auxiliary power negative terminal  2612 . A collector of the BJT  2616  is coupled to the auxiliary power positive terminal  2611 , and the emitter thereof is coupled to the positive end of the energy storage unit  2613 . One end of the resistor  2617  is coupled to the auxiliary power positive terminal  2611  and the other end is coupled to a base of the BJT  2616 . When the collector of the BJT  2616  is a cut-in voltage higher than the emitter thereof, the resistor  2617  conducts the BJT  2616 . When the power source provides power to the LED tube lamp normally, the energy storage unit  2613  is charged by the filtered signal through the filtering output terminals  521  and  522  and the conducted BJT  2616  or by the driving signal through the driving output terminals  1521  and  1522  and the conducted BJT  2616  unit that the collector-emitter voltage of the BJT  2616  is lower than or equal to the cut-in voltage. When the filtered signal or the driving signal is no longer being supplied or the level thereof is insufficient, the energy storage unit  2613  provides power through the diode  2615  to keep the LED driving module  530  or the LED module  630  continuously light. 
     It is worth noting that in some embodiments, the maximum voltage of the charged energy storage unit  2613  is the cut-in voltage of the BJT  2616  lower than a voltage difference applied between the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612 . The voltage difference provided between the auxiliary power positive terminal  2611  and the auxiliary power negative terminal  2612  is a turn-on voltage of the diode  2615  lower than the voltage of the energy storage unit  2613 . Hence, when the auxiliary power module  2610  provides power, the voltage applied at the LED module  630  is lower (about the sum of the cut-in voltage of the BJT  2616  and the turn-on voltage of the diode  2615 ). In the embodiment shown in the  FIG.  63 B , the brightness of the LED module  630  is reduced when the auxiliary power module supplies power thereto. Thereby, when the auxiliary power module is applied to an emergency lighting system or a constant lighting system, the user realizes the main power supply, such as commercial power, is abnormal and then performs necessary precautions therefor. 
       FIG.  64    is a block diagram of a power supply module in an LED tube lamp according to an embodiment of the present invention. Compared to the above mentioned embodiments, the circuits for driving the LED module is installed outside of the LED tube lamp. For example, the LED tube lamp  3500  is driven to emit light by an external driving power  3530  through external driving terminals  3501  and  3502 . The LED tube lamp  3500  comprises the LED module  630  and a current control circuit  3510 , and does not comprise the rectifying circuit, filtering circuit and the driving circuit. In the present embodiment, the external driving terminals  3501  and  3502  serve as the pins  501  and  502  shown in  FIG.  49 A  and  FIG.  49 B . 
     The external driving power  3530  may be directly connected with the commercial power or the ballast for receiving power and converting into an external driving signal to input into the LED tube lamp  3500  through the external driving terminals  3501  and  3502 . The external driving signal may be a DC signal, and may preferably be a stable DC current signal. Under a normal condition, the current control circuit  3510  conducts to have a current flowing through and driving the LED module  630  to emit light. The current control circuit  3510  may further detect the current of the LED module  630  for performing a steady current or voltage control and have a function of ripple filter. Under an abnormal condition, the current control circuit  3510  is cut off to stop inputting the power of the external driving power  3530  into the LED module  630  and enters into a protection state. 
     When the current control circuit  3510  determines that the current of the LED module  630  is lower than a defined current or a minimum current of a defined current range, the current control circuit  3510  is completely conducted, i.e., the impedance of the current control circuit  3510  comes down a minimum value. 
     When the current control circuit  3510  determines that the current of the LED module  630  is higher than a defined current or a maximum current of a defined current range, the current control circuit  3510  is cutoff to stop inputting power into the LED tube lamp  3500 . The maximum current of a defined current range is in some embodiments set at a value about 30% higher than a rated current of the LED module  630 . Thereby, the current control circuit  3510  can keep the brightness of the LED lamp as much as possible when a driving capability of the external driving power  3530  is reduced. Furthermore, the current control circuit  3510  can prevent the LED module  630  from over current when the driving capability of the external driving power  3530  is abnormally increased. Hence, the current control circuit  3510  has a function of over-current protection. 
     It is worth noting that the external driving power  3530  may be a DC voltage signal. Under a normal condition, the current control circuit  3510  stabilizes the current of the LED module  630  or controls the current linearly, e.g, the current of the LED module  630  is varied linearly with a level of the DC voltage signal. For controlling the current of the LED module at a current value or linearly, a voltage across the current control circuit  3510  is increased with the level of the DC voltage signal provided by the external driving power  3530  and a power consumption thereof is also increased. The current control circuit  3510  may have a temperature detector. When the level of the DC voltage signal provided by the external driving power  3530  is over a high threshold, the current control circuit  3510  enters into a state of over temperature protection to stop inputting power of the external driving power  3530  into the LED tube lamp  3500 . For example, when the temperature detector detects the temperature of the current control circuit  3510  at 120° C., the current control circuit  3510  enters into the state of over temperature protection. Thereby, the current control circuit  3510  has both over temperature and over voltage protections. 
     In some embodiments, due to the external driving power, the length of the end caps are shortened. For ensuring the total length of the LED tube lamp to conform to a standard for a fluorescent lamp, a length of the lamp tube is lengthened to compensate the shortened length of the end caps. Due to the lengthened length of the lamp tube, the LED light string is correspondingly lengthened. Therefore, the interval of adjacent two LEDs disposed on the LED light string becomes greater under the same illuminance requirement. The greater interval increases the heat dissipation of the LEDs and so the operation temperature of the LEDs is lowered and the life-span of the LED tube lamp is extended. 
     Referring to  FIG.  37   , in one embodiment, each of the LED light sources  202  may be provided with an LED lead frame  202   b  having a recess  202   a , and an LED chip  18  disposed in the recess  202   a . The recess  202   a  may be one or more than one in amount. The recess  202   a  may be filled with phosphor covering the LED chip  18  to convert emitted light therefrom into a desired light color. Compared with a conventional LED chip being a substantial square, the LED chip  18  in this embodiment may be preferably rectangular with the dimension of the length side to the width side at a ratio ranges generally from about 2:1 to about 10:1, in some embodiments from about 2.5:1 to about 5:1, and in some more desirable embodiments from about 3:1 to about 4.5:1. Moreover, the LED chip  18  is in some embodiments arranged with its length direction extending along the length direction of the lamp tube  1  to increase the average current density of the LED chip  18  and improve the overall illumination field shape of the lamp tube  1 . The lamp tube  1  may have a number of LED light sources  202  arranged into one or more rows, and each row of the LED light sources  202  is arranged along the length direction (Y-direction) of the lamp tube  1 . 
     Referring again to  FIG.  37   , the recess  202   a  is enclosed by two parallel first sidewalls  15  and two parallel second sidewalls  16  with the first sidewalls  15  being lower than the second sidewalls  16 . The two first sidewalls  15  are arranged to be located along a length direction (Y-direction) of the lamp tube  1  and extend along the width direction (X-direction) of the lamp tube  1 , and two second sidewalls  16  are arranged to be located along a width direction (X-direction) of the lamp tube  1  and extend along the length direction (Y-direction) of the lamp tube  1 . The extending direction of the first sidewalls  15  may be substantially rather than exactly parallel to the width direction (X-direction) of the lamp tube  1 , and the first sidewalls may have various outlines such as zigzag, curved, wavy, and the like. Similarly, the extending direction of the second sidewalls  16  may be substantially rather than exactly parallel to the length direction (Y-direction) of the lamp tube  1 , and the second sidewalls may have various outlines such as zigzag, curved, wavy, and the like. In one row of the LED light sources  202 , the arrangement of the first sidewalls  15  and the second sidewalls  16  for each LED light source  202  can be same or different. 
     Having the first sidewalls  15  being lower than the second sidewalls  16  and proper distance arrangement, the LED lead frame  202   b  allows dispersion of the light illumination to cross over the LED lead frame  202   b  without causing uncomfortable visual feeling to people observing the LED tube lamp along the Y-direction. In some embodiments, the first sidewalls  15  may not be lower than the second sidewalls, however, and in this case the rows of the LED light sources  202  are more closely arranged to reduce grainy effects. On the other hand, when a user of the LED tube lamp observes the lamp tube thereof along the X-direction, the second sidewalls  16  also can block user&#39;s line of sight from seeing the LED light sources  202 , and which reduces unpleasing grainy effects. 
     Referring again to  FIG.  37   , the first sidewalls  15  each includes an inner surface  15   a  facing toward outside of the recess  202   a . The inner surface  15   a  may be designed to be an inclined plane such that the light illumination easily crosses over the first sidewalls  15  and spreads out. The inclined plane of the inner surface  15   a  may be flat or cambered or combined shape. In some embodiments, when the inclined plane is flat, the slope of the inner surface  15   a  ranges from about 30 degrees to about 60 degrees. Thus, an included angle between the bottom surface of the recess  202   a  and the inner surface  15   a  may range from about 120 to about 150 degrees. In some embodiments, the slope of the inner surface  15   a  ranges from about 15 degrees to about 75 degrees, and the included angle between the bottom surface of the recess  202   a  and the inner surface  15   a  ranges from about 105 degrees to about 165 degrees. 
     There may be one row or several rows of the LED light sources  202  arranged in a length direction (Y-direction) of the lamp tube  1 . In case of one row, in one embodiment, the second sidewalls  16  of the LED lead frames  202   b  of all of the LED light sources  202  located in the same row are disposed in same straight lines to respectively form two walls for blocking the user&#39;s line of sight seeing the LED light sources  202 . In case of several rows, in some embodiments, only the LED lead frames  202   b  of the LED light sources  202  disposed in the outermost two rows are disposed in same straight lines to respectively form walls for blocking user&#39;s line of sight seeing the LED light sources  202 . In case of several rows, it may be required only that the LED lead frames  202   b  of the LED light sources  202  disposed in the outermost two rows are disposed in same straight lines to respectively from walls for blocking user&#39;s line of sight seeing the LED light sources  202 . The LED lead frames  202   b  of the LED light sources  202  disposed in the other rows can have different arrangements. For example, as far as the LED light sources  202  located in the middle row (third row) are concerned, the LED lead frames  202   b  thereof may be arranged such that: each LED lead frame  202   b  has the first sidewalls  15  arranged along the length direction (Y-direction) of the lamp tube  1  with the second sidewalls  16  arranged along in the width direction (X-direction) of the lamp tube  1 ; each LED lead frame  202   b  has the first sidewalls  15  arranged along the width direction (X-direction) of the lamp tube  1  with the second sidewalls  16  arranged along the length direction (Y-direction) of the lamp tube  1 ; or the LED lead frames  202   b  are arranged in a staggered manner. To reduce grainy effects caused by the LED light sources  202  when a user of the LED tube lamp observes the lamp tube thereof along the X-direction, it may be enough to have the second sidewalls  16  of the LED lead frames  202   b  of the LED light sources  202  located in the outmost rows to block user&#39;s line of sight from seeing the LED light sources  202 . Different arrangements may be used for the second sidewalls  16  of the LED lead frames  202   b  of one or several of the LED light sources  202  located in the outmost two rows. 
     In summary, when a plurality of the LED light sources  202  are arranged in a row extending along the length direction of the lamp tube  1 , the second sidewalls  16  of the LED lead frames  202   b  of all of the LED light sources  202  located in the same row may be disposed in same straight lines to respectively form walls for blocking user&#39;s line of sight seeing the LED light sources  202 . When a plurality of the LED light sources  202  are arranged in a number of rows being located along the width direction of the lamp tube  1  and extending along the length direction of the lamp tube  1 , the second sidewalls  16  of the LED lead frames  202   b  of all of the LED light sources  202  located in the outmost two rows may be disposed in straight lines to respectively form two walls for blocking user&#39;s line of sight seeing the LED light sources  202 . The one or more than one rows located between the outmost rows may have the first sidewalls  15  and the second sidewalls  16  arranged in a way the same as or different from that for the outmost rows. 
     As to  FIG.  65   ,  FIG.  65    illustrates a block diagram of an exemplary power supply module in an LED tube lamp according to one embodiment of the present invention. This embodiment is a combination of some features described in  FIGS.  2 ,  52 D,  51 A,  50 C,  52 B, and  53 A . According to this embodiment, the LED tube lamp comprises a lamp tube  1 , a heat shrink sleeve  190  covering on an outer surface of the lamp tube  1 , an LED light strip  2  in the lamp tube  1 , a plurality of LED light sources  202  (similar to LEDs  631  in  FIG.  53 A ) on the LED light strip  2 , two end caps  3  respectively coupled to two opposite ends of the lamp tube  1 , and a power supply circuit  258  on the light strip  2 . The power supply circuit  258  comprises a plurality of electronic components. 
     The LED light strip  2  with the plurality of LED light sources  202  and power supply circuit  258  is in the lamp tube  1 . In other words, all the electronic components of the power supply circuit  258  are on the light strip  2 . Each of the end caps  3  comprises two conductive pins  301  for receiving an external driving signal. The electrical connection between the LED light strip  2  and the pins  301  may be achieved by wire bonding. 
     In one embodiment, the thickness of the heat shrink sleeve  190  is from 20 um to 200 um and the heat shrink sleeve  190  is substantially transparent with respect to wavelength of light from the plurality of LED light sources  202 . 
     In one embodiment, the LED tube lamp further comprises a reflective film  12  on an inner circumferential surface of the lamp tube  1 . The ratio of a circumferential length of the reflective film  12  along the inner circumferential surface of the lamp tube  1  to a circumferential length of the lamp tube  1  is about 0.3 to 0.5. The reflective film  12  has an opening  12   a  for accommodating the LED light strip  2 . 
     In one embodiment, the LED tube lamp further comprises a diffusion film  13  on the inner surface of the lamp tube  1 . 
     In one embodiment, the LED light strip  2  has a widened part occupying a circumference area of the inner surface of the lamp tube  1  and a ratio of the length of the LED light strip  2  along the circumferential direction to the circumferential length of the lamp tube  1  is about 0.3 to 0.5. 
     In one embodiment, the LED light strip  2  is fixed by an adhesive sheet to an inner circumferential surface of the lamp tube. 
     In one embodiment, the power supply circuit  258  comprises a rectifying circuit  810 , a filtering circuit  623 , and an LED module  630 . The rectifying circuit  810  is configured to receive and rectify the external driving signal from the two pins  301  (shown as pins  501  and  502  in  FIG.  65   ) of corresponding one of the end caps  3  and then produce a rectified signal. In this embodiment, the power supply circuit  258  may comprise two rectifying circuits  810  (similar to the rectifying circuits  810  in  FIG.  50 C ), which may respectively correspond to the rectifying circuit  510  and the rectifying circuit  540  mentioned above in  FIG.  49 E . 
     The filtering circuit  623  is connected to the rectifying circuit  810  and configured to produce a filtered signal. In one embodiment, the power supply circuit  258  may comprise two filtering circuits  623  and the filtering circuits  623  may be referred to as filtering units  623  of  FIG.  52 B . Each of the filtering circuits  623  filters the rectified signal as from corresponding one of the rectifying circuits  810  to produce a filtered signal. The LED module  630  has the plurality of LED light sources  202  ( 631 ) for receiving the filtered signal and emitting light. 
     “Corresponding” in above paragraph means the electrical circuit/component on the same side of the lamp tube  1 . For example, the rectifying circuit  810  on the left side of  FIG.  65    corresponds to the end cap  3  on the left side, and the two pins  301  on the left side, the filtering circuit  623  on the left side, if any. Likewise, the rectifying circuit  810  on the right side of  FIG.  65    if any corresponds to the end cap  3  on the right side and the two pins  301  on the right side, and the filtering circuit  623  on the right side, if any. 
     The power supply circuit  258  may further comprise a filtering unit  824  as mentioned above in  FIG.  52 D . The filtering unit  824  is connected between one pin of one of the two end caps and the rectifying circuit  810 . In some embodiments, the filtering unit  824  comprises an inductor  828 . The rectifying circuit  810  comprises a current-limiting capacitor  642  and a rectifying unit  815  connected with the current-limiting capacitor  642 . The filtering circuit  623  comprises a capacitor  625 . In this embodiment, the power supply circuit  258  may comprise four filtering units  824  as shown in  FIG.  65    (the filtering unit  824  is similar to that in  FIG.  52 D ). The filtering units  824  are, respectively, connected between the four pins  301  and the corresponding rectifying circuits  810 . Specifically, the pins  301  on the left side are connected to the rectifying circuit  810  on the left side of the  FIG.  65    while the pins  301  on the right side are connected to the rectifying circuit  810  on the right side of the  FIG.  65   . In one embodiment, the filtering units  824  each comprise an inductor  828 . And each of the rectifying circuits  810  comprises a current-limiting capacitor  642  and a half-wave rectifying unit  815  connected with the current-limiting capacitor  642 . It should be noted that current-limiting capacitor  642  can be a part of, or be regarded as belonging to, a terminal adapter circuit  541  introduced in  FIGS.  50 C and  50 D  and also marked in  FIG.  65   . And each of the four inductors  828  in  FIG.  65    can alternatively be regarded as a part of the terminal adapter circuit  541  in  FIG.  65   , since it&#39;s mentioned above that a terminal adapter circuit  541  (as in  FIGS.  50 C and  50 D ) may comprise a resistor, a capacitor, an inductor, or any combination thereof. In one embodiment, each of the end caps  3  comprises a plurality of openings  304  formed on the end caps. The plurality of openings  304  of one of the end caps  3  are symmetric to each other with respect to a plane passing through the middle of a line connecting the two pins  301  and perpendicular to the line connecting the two pins  301 . The number of the openings  304  on one of the end caps  3  is two. Alternatively, the number of the plurality of openings  304  on one of the end caps is three and the three openings  304  are arranged in a shape of an arc. All the electronic components of the power supply circuit  258  including the rectifying circuits  810 , the filtering circuits  623 , the LED module  630 , and the filtering units  824  are on the LED light strip  2 . The filtering units  824  are inductors  828  and the inductors  828  are closer to the openings  304  of corresponding one of the end caps  3 . Accordingly, heat from the inductors  828  may be dissipated more efficiently. 
     In one embodiment, the LED tube lamp further comprises a hot melt adhesive. The end caps  3  are adhered, respectively, to opposite ends of the lamp tube  1  via the hot melt adhesive. 
     The LED tube lamps according to various different embodiments of the present invention are described as above. With respect to an entire LED tube lamp, the features including “having the structure-strengthened end region”, “adopting the bendable circuit sheet as the LED light strip”, “coating the adhesive film on the inner surface of the lamp tube”, “coating the diffusion film on the inner surface of the lamp tube”, “covering the diffusion film in form of a sheet above the LED light sources”, “coating the reflective film on the inner surface of the lamp tube”, “the end cap including the thermal conductive member”, “the end cap including the magnetic metal member”, “the LED light source being provided with the lead frame”, and “utilizing the circuit board assembly to connect the LED light strip and the power supply” may be applied in practice singly or integrally such that only one of the features is practiced or a number of the features are simultaneously practiced. 
     Furthermore, any of the features “having the structure-strengthened end region”, “adopting the bendable circuit sheet as the LED light strip”, “coating the adhesive film on the inner surface of the lamp tube”, “coating the diffusion film on the inner surface of the lamp tube”, “covering the diffusion film in form of a sheet above the LED light sources”, “coating the reflective film on the inner surface of the lamp tube”, “the end cap including the thermal conductive member”, “the end cap including the magnetic metal member”, “the LED light source being provided with the lead frame”, “utilizing the circuit board assembly (including a long circuit sheet and a short circuit board) to connect the LED light strip and the power supply”, “a rectifying circuit”, “a filtering circuit”, “a driving circuit”, “a terminal adapter circuit”, “an anti-flickering circuit”, “a protection circuit”, “a mode switching circuit”, “an overvoltage protection circuit”, “a ballast detection circuit”, “a ballast-compatible circuit”, “a filament-simulating circuit”, and “an auxiliary power module” includes any related technical points and their variations and any combination thereof as described in the abovementioned embodiments of the present invention. 
     As an example, the feature “having the structure-strengthened end region” may include “the lamp tube includes a main body region, a plurality of rear end regions, and a transition region connecting the main body region and the rear end regions, wherein the two ends of the transition region are arc-shaped in a cross-section view along the axial direction of the lamp tube; the rear end regions are respectively sleeved with end caps; the outer diameter of at least one of the rear end regions is less than the outer diameter of the main body region; the end caps have same outer diameters as that of the main body region.” 
     As an example, the feature “adopting the bendable circuit sheet as the LED light strip” includes “the connection between the bendable circuit sheet and the power supply is by way of wire bonding or soldering bonding; the bendable circuit sheet includes a wiring layer and a dielectric layer arranged in a stacked manner; the bendable circuit sheet has a circuit protective layer made of ink to reflect lights and has widened part along the circumferential direction of the lamp tube to function as a reflective film.” 
     As an example, the feature “coating the diffusion film on the inner surface of the lamp tube” may include “the composition of the diffusion film includes calcium carbonate, halogen calcium phosphate and aluminum oxide, or any combination thereof, and may further include thickener and a ceramic activated carbon; the diffusion film may be a sheet covering the LED light source.” 
     As an example, the feature “coating the reflective film on the inner surface of the lamp tube” may include “the LED light sources are disposed above the reflective film, within an opening in the reflective film or beside the reflective film.” 
     As an example, the feature “the end cap including the thermal conductive member” may include “the end cap includes an electrically insulating tube, the hot melt adhesive is partially or completely filled in the accommodation space between the inner surface of the thermal conductive member and the outer surface of the lamp tube.” The feature “the end cap including the magnetic metal member” may include “the magnetic metal member is circular or non-circular, has openings or indentation/embossment to reduce the contact area between the inner peripheral surface of the electrically insulating tube and the outer surface of the magnetic metal member; has supporting portions and protruding portions to support the magnetic metal member or reduce the contact area between the electrically insulating tube and the magnetic metal member.” 
     As an example, the feature “the LED light source being provided with the lead frame” may include “the lead frame has a recess for receiving an LED chip, the recess is enclosed by first sidewalls and second sidewalls with the first sidewalls being lower than the second sidewalls, wherein the first sidewalls are arranged to locate along a length direction of the lamp tube while the second sidewalls are arranged to locate along a width direction of the lamp tube.” 
     As an example, the feature “utilizing the circuit board assembly to connect the LED light strip and the power supply” may include “the circuit board assembly has a long circuit sheet and a short circuit board that are adhered to each other with the short circuit board being adjacent to the side edge of the long circuit sheet; the short circuit board is provided with a power supply module to form the power supply; the short circuit board is stiffer than the long circuit sheet.” 
     According to the design of the power supply module, the external driving signal may be low frequency AC signal (e.g., commercial power), high frequency AC signal (e.g., that provided by a ballast), or a DC signal (e.g., that provided by a battery), input into the LED tube lamp through a drive architecture of single-end power supply or dual-end power supply. For the drive architecture of dual-end power supply, the external driving signal may be input by using only one end thereof as single-end power supply. 
     The LED tube lamp may omit the rectifying circuit when the external driving signal is a DC signal. 
     According to the design of the rectifying circuit in the power supply module, there may be a signal rectifying circuit, or dual rectifying circuit. First and second rectifying circuits of the dual rectifying circuit are respectively coupled to the two end caps disposed on two ends of the LED tube lamp. The single rectifying circuit is applicable to the drive architecture of signal-end power supply, and the dual rectifying circuit is applicable to the drive architecture of dual-end power supply. Furthermore, the LED tube lamp having at least one rectifying circuit is applicable to the drive architecture of low frequency AC signal, high frequency AC signal or DC signal. 
     The single rectifying circuit may be a half-wave rectifier circuit or full-wave bridge rectifying circuit. The dual rectifying circuit may comprise two half-wave rectifier circuits, two full-wave bridge rectifying circuits or one half-wave rectifier circuit and one full-wave bridge rectifying circuit. 
     According to the design of the pin in the power supply module, there may be two pins in single end (the other end has no pin), two pins in corresponding end of two ends, or four pins in corresponding end of two ends. The designs of two pins in single end two pins in corresponding end of two ends are applicable to signal rectifying circuit design of the of the rectifying circuit. The design of four pins in corresponding end of two ends is applicable to dual rectifying circuit design of the of the rectifying circuit, and the external driving signal can be received by two pins in only one end or in two ends. 
     According to the design of the filtering circuit of the power supply module, there may be a single capacitor, or π filter circuit. The filtering circuit filters the high frequency component of the rectified signal for providing a DC signal with a low ripple voltage as the filtered signal. The filtering circuit also further comprises the LC filtering circuit having a high impedance for a specific frequency for conforming to current limitations in specific frequencies of the UL standard. Moreover, the filtering circuit according to some embodiments further comprises a filtering unit coupled between a rectifying circuit and the pin(s) for reducing the EMI. 
     According to the design of the LED driving module of the power supply module according to some embodiments, the LED driving may comprise the LED module and the driving circuit or only the LED module. The LED module may be connected with a voltage stabilization circuit for preventing the LED module from over voltage. The voltage stabilization circuit may be a voltage clamping circuit, such as zener diode, DIAC and so on. When the rectifying circuit has a capacitive circuit, in some embodiments, two capacitors are respectively coupled between corresponding two pins in two end caps and so the two capacitors and the capacitive circuit as a voltage stabilization circuit perform a capacitive voltage divider. 
     If there are only the LED module in the LED driving module and the external driving signal is a high frequency AC signal, a capacitive circuit is in at least one rectifying circuit and the capacitive circuit is connected in series with a half-wave rectifier circuit or a full-wave bridge rectifying circuit of the rectifying circuit and serves as a current modulation circuit to modulate the current of the LED module due to that the capacitor equates a resistor for a high frequency signal. Thereby, even different ballasts provide high frequency signals with different voltage levels, the current of the LED module can be modulated into a defined current range for preventing overcurrent. In addition, an energy-releasing circuit is connected in parallel with the LED module. When the external driving signal is no longer supplied, the energy-releasing circuit releases the energy stored in the filtering circuit to lower a resonance effect of the filtering circuit and other circuits for restraining the flicker of the LED module. 
     In some embodiments, if there are the LED module and the driving circuit in the LED driving module, the driving circuit may be a buck converter, a boost converter, or a buck-boost converter. The driving circuit stabilizes the current of the LED module at a defined current value, and the defined current value may be modulated based on the external driving signal. For example, the defined current value may be increased with the increasing of the level of the external driving signal and reduced with the reducing of the level of the external driving signal. Moreover, a mode switching circuit may be added between the LED module and the driving circuit for switching the current from the filtering circuit directly or through the driving circuit inputting into the LED module. 
     A protection circuit may be additionally added to protect the LED module. The protection circuit detects the current and/or the voltage of the LED module to determine whether to enable corresponding over current and/or over voltage protection. 
     According to the design of the ballast detection circuit of the power supply module, the ballast detection circuit is substantially connected in parallel with a capacitor connected in series with the LED module and determines the external driving signal whether flowing through the capacitor or the ballast detection circuit (i.e., bypassing the capacitor) based on the frequency of the external driving signal. The capacitor may be a capacitive circuit in the rectifying circuit. 
     According to the design of the filament-simulating circuit of the power supply module, there may be a single set of a parallel-connected capacitor and resistor, two serially connected sets, each having a parallel-connected capacitor and resistor, or a negative temperature coefficient circuit. The filament-simulating circuit is applicable to program-start ballast for avoiding the program-start ballast determining the filament abnormally, and so the compatibility of the LED tube lamp with program-start ballast is enhanced. Furthermore, the filament-simulating circuit almost does not affect the compatibilities for other ballasts, e.g., instant-start and rapid-start ballasts. 
     According to the design of the ballast-compatible circuit of the power supply module in some embodiments, the ballast-compatible circuit can be connected in series with the rectifying circuit or connected in parallel with the filtering circuit and the LED driving module. Under the design of being connected in series with the rectifying circuit, the ballast-compatible circuit is initially in a cutoff state and then changes to a conducting state in an objective delay. Under the design of being connected in parallel with the filtering circuit and the LED driving module, the ballast-compatible circuit is initially in a conducting state and then changes to a cutoff state in an objective delay. The ballast-compatible circuit makes the electronic ballast really activate during the starting stage and enhances the compatibility for instant-start ballast. Furthermore, the ballast-compatible circuit almost does not affect the compatibilities with other ballasts, e.g., program-start and rapid-start ballasts. 
     According to the design of the auxiliary power module of the power supply module, the energy storage unit may be a battery or a supercapacitor, connected in parallel with the LED module. The auxiliary power module is applicable to the LED driving module having the driving circuit. 
     According to the design of the LED module of the power supply module, the LED module comprises plural strings of LEDs connected in parallel with each other, wherein each LED may have a single LED chip or plural LED chips emitting different spectrums. Each LEDs in different LED strings may be connected with each other to form a mesh connection. 
     Referring to  FIG.  66    and  FIG.  67   , the instant disclosure provides an embodiment of an LED tube lamp  50  which comprises a tube  100 , an LED light strip  200 , and end caps  300 . The LED light strip  200  is disposed inside the tube  100 . Two end caps  300  are respectively disposed on two ends of the tube  100 . The LED tube lamp  100  can be a plastic tube, a glass tube, a plastic-metal combined tube, or a glass-metal combined tube. The two end caps  300  can have the same size or have different sizes. Referring to  FIG.  67   , several LED light sources  202  are disposed on the LED light strip  200 , and a power supply  400  is disposed in the end cap  300 . The power supply  400  may be in the form of a single integrated unit (e.g., with all components of the power supply  400  are within a body) disposed in an end cap  300  at one end of the tube  100 . Alternatively, the power supply  400  may be in form of two separate parts (e.g., with the components of the power supply  400  are separated into two pieces) respectively disposed in two end caps  300 . The LED light sources  202  and the power supply  400  can be electrically connected to each other via the LED light strip  200 . The LED light strip  200  can be a bendable circuit sheet. Moreover, in some embodiments, the length of the bendable circuit sheet is greater than the length of the tube  100  (not including the length of the two end caps  300  respectively connected to two ends of the tube  100 ), or at least greater than a central portion of the tube  100  between two transition regions (e.g., where the circumference of the tube narrows) on either end. In one embodiment, the longitudinally projected length of the bendable circuit sheet as the LED light strip  200  is larger than the length of the tube  100 . Middle part of the LED light strip  200  can be mounted on the inner surface of the tube  100 . Instead, two opposite, short edges of the LED light strip  200  are not mounted on the inner surface of the tube  100 . The LED light strip  200  comprises two freely extending end portions  210 . The two freely extending end portions  210  are respectively disposed on the two opposite, short edges of the LED light strip  200 . The two freely extending end portions  210  respectively extend outside the tube  100  through two holes at two opposite ends of the tube  100  along the axial direction of the tube  100 . The two freely extending end portions  210  can respectively extend to inside area of the end caps  300  and can be electrically connected to the power supply  400 . Each of the end caps  300  comprises a pair of hollow conductive pins  301  utilized for being connected to an outer electrical power source. When the LED tube lamp  50  is installed to a lamp base, the hollow conductive pins  301  are plugged into corresponding conductive sockets of the lamp base such that the LED tube lamp  50  can be electrically connected to the lamp base. In one embodiment, the LED light strip  2  includes a bendable circuit sheet having a conductive wiring layer and a dielectric layer that are arranged in a stacked manner, wherein the wiring layer and the dielectric layer have same area or the wiring layer has a bit less area (not shown) than the dielectric layer. The LED light source  202  is disposed on one surface of the wiring layer, the dielectric layer is disposed on the other surface of the wiring layer that is away from the LED light sources  202 . The wiring layer is electrically connected to the power supply  400  to carry direct current (DC) signals. Meanwhile, the surface of the dielectric layer away from the wiring layer is fixed to the inner circumferential surface of the tube  100  by means of the adhesive sheet (not shown). The wiring layer can be a metal layer or a power supply layer including wires such as copper wires. 
     In another embodiment, the outer surface of the wiring layer or the dielectric layer may be covered with a circuit protective layer made of an ink with function of resisting soldering and increasing reflectivity (not shown). Alternatively, the dielectric layer can be omitted and the wiring layer can be directly bonded to the inner circumferential surface of the tube  100 , and the outer surface of the wiring layer is coated with the circuit protective layer. Whether the wiring layer has a one-layered, or two-layered structure, the circuit protective layer can be adopted. In some embodiments, the circuit protective layer is disposed only on one side/surface of the LED light strip  200 , such as the surface having the LED light source  202 . In some embodiments, the bendable circuit sheet is a one-layered structure made of just one wiring layer, or a two-layered structure made of one wiring layer and one dielectric layer, and thus is more bendable or flexible to curl when compared with the conventional three-layered flexible substrate (one dielectric layer sandwiched with two wiring layers). As a result, the bendable circuit sheet of the LED light strip  200  can be installed in a tube with a customized shape or non-tubular shape, and fitly mounted to the inner surface of the tube  100 . The bendable circuit sheet closely mounted to the inner surface of the tube  100   n  is preferable in some cases. In addition, using fewer layers of the bendable circuit sheet improves the heat dissipation and lowers the material cost. 
     Nevertheless, the bendable circuit sheet is not limited to being one-layered or two-layered; in other embodiments, the bendable circuit sheet may include multiple layers of the wiring layers and multiple layers of the dielectric layers, in which the dielectric layers and the wiring layers are sequentially stacked in a staggered manner, respectively (not shown). These stacked layers are away from the surface of the outermost wiring layer which has the LED light source  202  disposed thereon and is electrically connected to the power supply  400 . Moreover, the projected length of the bendable circuit sheet is greater than the length of the tube  100 . 
     In one embodiment, the LED light strip  200  includes a bendable circuit sheet having in sequence a first wiring layer, a dielectric layer, and a second wiring layer (not shown). The thickness of the second wiring layer is greater than that of the first wiring layer, and/or the projected length of the LED light strip  200  is greater than that of the tube  100 . The end region of the light strip  200  extending beyond the end portion of the tube  100  without disposition of the light source  202  is formed with two separate through holes to respectively electrically communicate the first wiring layer and the second wiring layer (not shown). The through holes are not communicated to each other to avoid short circuit. 
     In this way, the greater thickness of the second wiring layer allows the second wiring layer to support the first wiring layer and the dielectric layer, and meanwhile allow the LED light strip  200  to be mounted onto the inner circumferential surface without being liable to shift or deform, and thus the yield rate of product can be improved. In addition, the first wiring layer and the second wiring layer are in electrical communication such that the circuit layout of the first wiring layer can be extended downward to the second wiring layer to reach the circuit layout of the entire LED light strip  200 . In some circumstances, the first wiring connects the anode and the second wiring connects the cathode. Moreover, since the land for the circuit layout becomes two-layered, the area of each single layer and therefore the width of the LED light strip  200  can be reduced such that more LED light strips  200  can be put on a production line to increase productivity. Furthermore, the first wiring layer and the second wiring layer of the end region of the LED light strip  200  that extends beyond the end portion of the tube  100  without disposition of the light source  202  can be used to accomplish the circuit layout of a power supply  400  so that the power supply  400  can be directly disposed on the bendable circuit sheet of the LED light strip  200 . 
     As shown in  FIG.  67   , the tube  100  comprises two rear end regions  101 , two transition regions, and one main body region  102 . The two rear end regions  101  are at two opposites ends of the main body region  102 . The two transition regions are respectively between the two rear end regions  101  and the main body region  102 . The two end caps  300  are respectively connected to the two rear end regions  101 . The rear end regions  101  are the portions of the tube  100  shrunk in the radial direction. The rear end regions  101  form shrunk holes. The bore of the rear end region  101  is less than that of the main body region  102 . In other words, in the transition region, the tube  100  narrows, or tapers to have a smaller diameter when moving along the length of the tube  100  from the main body region  102  to the rear end region  101 . The tapering/narrowing may occur in a continuous, smooth manner (e.g., to be a smooth curve without any linear angles). By avoiding angles, in particular any acute angles, the tube  100  is less likely to break or crack under pressure. Furthermore, the transition region is formed by two curves at both ends, wherein one curve is toward inside of the tube  100  and the other curve is toward outside of the tube  100 . For example, one curve closer to the main body region  102  is convex from the perspective of an inside of the tube  100  and one curve closer to the rear end region  101  is concave from the perspective of an inside of the tube  100 . The transition region of the tube  100  in one embodiment includes only smooth curves, and does not include any angled surface portions. As shown in  FIG.  816   , the appearance of the LED tube lamp  50  is identical from the tube  100  to the end caps  300 , meaning that the outer surfaces of the end caps  300  are aligned with that of the tube  100 . 
     Referring to  FIG.  68    and  FIG.  69   ,  FIG.  68    is a partial view of the LED tube lamp  50 , and  FIG.  69    is a cross section of  FIG.  68    along the line A-A′. The end cap  300  of the embodiment further comprises a lateral wall  304 , an end wall  302 , and an opening  320 . The lateral wall  304  is tubular shape. The lateral wall  304  and the tube  100  are coaxial and are connected to each other. More specifically, the lateral wall  304  and the tube  100  are substantially coaxial but the alignment of the axial directions of the lateral wall  304  and the tube  100  may have a slightly shift due to manufacturing tolerance. The end wall  302  is substantially perpendicular to the axial direction of the lateral wall  304 . The end wall  302  is connected to an end of the lateral wall  304  away from the tube  100 . More specifically, the end wall  302  is substantially perpendicular to the axial direction of the lateral wall  304  but the angle between the end wall  302  and the axial direction of the lateral wall  304  may not be exactly 90 degrees maybe due to manufacturing tolerance. This is still within the scope of substantially perpendicular. Even if the end wall  302  relative to the axial direction of the lateral wall  304  is slightly inclined, the end wall  302  and the lateral wall  304  can still form a receiving space for receiving the power supply  400  and can mate the lamp base. The end wall  302  and the lateral wall  304  form an inner space of the end cap  300 . The power supply  400  is disposed in the inner space of the end cap  300 . The opening  320  penetrates through the end wall  302 . The inner space of the end cap  300  can communicate with outside area through the opening  320 . Air can flow through the opening  320  between the inner space of the end cap  300  and outside area. Moreover, the opening  320  is good for pressure releasing, and a light sensor can be configured inside the end cap  300  to collimate with the opening  320  for light detection and electric-shock prevention during installation of the LED tube lamp  50  to a lamp base (not shown). 
     The power supply  400  can be a module, e.g., an integrated power module. The power supply  400  may be in the form of a single integrated unit (e.g., with all components of the power supply  400  are within a body) disposed in an end cap  300  at one end of the tube  100 . Alternatively, the power supply  400  may be in form of two separate parts (e.g., with the components of the power supply  400  are separated into two pieces) respectively disposed in two end caps  300 . The power supply  400  further comprises a pair of metal wires  410 . The metal wires  410  extend from the power supply  400  to the inside of the hollow conductive pins  301  and are connected to the hollow conductive pins  301 . In other words, the power supply  400  can be electrically connected to the outer electrical power source through the metal wires  410  and the hollow conductive pins  301 . The hollow conductive pins  301  are disposed outside the end wall  302  and extend along the axial direction of the lateral wall  304 . Referring to  FIG.  69   , when the LED tube lamp  50  is installed to a horizontal lamp base (not shown), the axle of the lateral wall  304  is substantially parallel with the horizontal direction “H”, and the pair of the hollow conductive pins  301  are at the same altitude and overlap each other in the vertical direction “V”. Under the circumstances, the altitude of the opening  320  is higher than that of the axle of the lateral wall  304  in the vertical direction “V”. 
     In the embodiment, as shown in  FIG.  69   , the axial direction of the opening  320  is substantially parallel with that of the lateral wall  304 . The axial direction of the opening  320  is defined as an extending direction of the opening  320  extending from the inner surface of the end wall  302  (the surface inside the end cap  300 ) to the outer surface of the end wall  302  (the surface outside). In the embodiment, the opening  320  is substantially aligned with the inner surface of the lateral wall  304  (the surface inside the end cap  300 ). Specifically, a part of the inner surface of the opening  320  is substantially aligned with a part of the inner surface of the lateral wall  304 . 
     In the embodiment, as shown in  FIG.  69   , an end wall radius “r” is defined as the shortest distance between the center of the end wall  302  (the point of the end wall  302  through which the axle of the lateral wall  304  passes) and the periphery of the end wall  302  in the radial direction of the end cap  300  (the direction substantially parallel with the vertical direction “V” shown in  FIG.  69   ). A distance “L” is defined as the shortest distance between the center of the end wall  302  and the opening  320  in the radial direction of the end cap  300 . The distance “L” is a ratio from 2/5 to 4/5 of the end wall radius “r”. That is to say, the relation of the opening  320  and the end wall  302  matches an equation listed below:
 
0.4r≤L≤0.8r
 
     When the position of the opening  320  relative to the center of the end wall  302  matches the aforementioned equation, the convection of air between the LED tube lamp  50  and outside area can be performed more efficiently. 
     In some embodiments, an LED tube lamp comprise a tube  50 , an LED light strip  200  disposed inside the tube  50 , a plurality of LED light sources  202  mounted on the LED light strip  200 , a power supply  400 , a first end cap  300 , and a second end cap  300 . The power supply  400  comprises a circuit board  420  (referring to  FIG.  81   ), a plurality of electronic components and a heat-dissipating element  440   a  (referring to  FIG.  81   ). At least a part of the plurality of electronic components and the heat-dissipating element  440   a  are on the circuit board. The first end cap  300  and the second end cap  300  are respectively attached at two ends of the tube  50 . Each of the first and second end caps  300  comprises a lateral wall  304  and an end wall  302  having an opening  320 . The lateral wall  304  is substantially coaxial with the tube  50  and connected to the tube  50 . The end wall  302  is substantially perpendicular to an axial direction of the lateral wall  304  and connected to an end of the lateral wall  304  away from the tube  50 . The circuit board is inside the first end cap  300 . The heat-dissipating element  440   a  is disposed closer to the opening  320  on the end wall  302  of the first end cap than are the plurality of the electronic components disposed in the first end cap  300 . 
     According to some embodiments, all of the plurality of electronic components is on the circuit board  420 . 
     According to some embodiments, a part, instead of its entirety, of the circuit board  420  is in the first end cap  300 . 
     According to some embodiments, the power supply  400  comprises another circuit board  420 , a plurality of another electronic components and another heat-dissipating element  440   a . At least a part of the plurality of another electronic components and the another heat-dissipating element  440   a  are on the another circuit board  420 . The another circuit board  420  is inside the second end cap  300 . The another heat-dissipating element  440   a  is closer to the opening  320  on the end wall  302  of the second end cap  300  than are the part of the plurality of the another electronic components in the second end cap  300 . 
     According to some embodiments, all of the plurality of another electronic components is on the another circuit board  420 . 
     According to some embodiments, a part, instead of its entirety, of the another circuit board  420  is in the second end cap. 
     Referring to  FIG.  70   , the difference between the LED tube lamps  50  of  FIG.  70    and  FIG.  69    is the forms of the openings  320 . In the embodiment, as shown in  FIG.  70   , the opening  320  can be inclined. The axial direction of the opening  320  and the axial direction of the lateral wall  304  define an angle  61 . The angle  61  is an acute angle. The axial direction of the opening  320  is defined as an extending direction of the opening  320  extending from the inner surface of the end wall  302  to the outer surface of the end wall  302 . When the LED tube lamp  50  is installed to the horizontal lamp base, the axial directions of the tube  100  and the end cap  300  are substantially parallel with the horizontal direction “H”, and the altitude of the opening  320  is higher than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V”. When the power supply  400  generates heat in operation, the inclined opening  320  shown in  FIG.  70    is beneficial to the process that heated air rises (along the vertical direction “V”) and flows to outside area through the opening  320 . 
     Additionally, two openings  320  are acceptable. As shown in  FIG.  70   , two inclined openings  320  are substantially symmetrical to each other. When the LED tube lamp  50  is installed to the horizontal lamp base, the axial directions of the tube  100  and the end cap  300  are substantially parallel with the horizontal direction “H”, and the altitude of one of the two openings  320  is higher than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V” while the other one of the two openings  320  is lower than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V”. Each of the axial directions of the two openings  320  and the axial direction of the lateral wall  304  respectively define an acute angle. When the power supply  400  generates heat in operation, the upper opening  320  shown in  FIG.  70    is beneficial to the process that heated air rises (along the vertical direction “V”) and flows to outside area through the upper opening  320 , and the lower opening  320  shown in  FIG.  70    is beneficial to the process that cool air from outside area flow to inside of the end cap  300  through the lower opening  320 . As a result, convection of the heated air and cool air is improved, and, consequently, the effect of heat dissipation is better. 
     Referring to  FIG.  71   , the difference between the LED tube lamps  50  of  FIG.  71    and  FIG.  69    is the forms of the openings  320 . As shown in  FIG.  71   , the opening  320  is not aligned with the inner surface of the lateral wall  304 . Comparing to the opening  320  of  FIG.  69   , the opening  320  of  FIG.  71    is away from the end wall  302 . 
     If the opening  320  is too large, dust from outside area may easily pass through the opening  320  and enter the inner space of the end cap  300 . Dust may accumulate on the power supply  400  and negatively affect heat dissipation. To prevent dust from passing through the opening  320 , the radial area of the opening  320  is preferably less than 1/10 of the radial area of the end wall  302 . Under the circumstances, dust is restricted to pass through the opening  320  to enter the inner space of the end cap  300 . In an example that the LED tube lamp  50  is a T8 tube lamp of which the external diameter of the tube  100  is 25 mm to 28 mm, and the external diameter of the end cap  300  (i.e., the diameter of the end wall  302  in the vertical direction “V” shown in  FIG.  69   ) is equal to that of the tube  100 . If the diameter of the end wall  302  in the vertical direction “V” shown in  FIG.  69    is 25 mm, the area of the end wall  302  in the vertical direction “V” is 490.625 mm2 (square of the radius of the end wall  302  times 3.14), and the bore area (the radial area) of the opening  320  in the vertical direction “V” is 0.5 mm2 to 6 mm2. For example, the radial area of the opening  320  is 6 mm2 and the radial area of the end wall  302  is 490.625 mm2, the radial area of the opening  320  is about 1/100 of the radial area of the end wall  302 . Under the circumstances, dust is hard to pass through the opening  320  to enter the inner space of the end cap  300 . In different embodiments, the bore area (the radial area) of the opening  320  in the vertical direction “V” is 0.5 mm2 to 3 mm2. Under the circumstances, dust is much harder to pass through the opening  320  to enter the inner space of the end cap  300 . 
     In different embodiments, the end cap  300  further comprises a dust-proof net (not shown). The dust-proof net is a net with fine meshes. The dust-proof net can cover the opening  320 . For example, the dust-proof net can be mounted on the outer surface or the inner surface of the end wall  302  and cover the opening  320 . As a result, the dust-proof net can prevent dust from entering the opening  320  and improve ventilation. 
     Referring to  FIG.  72   , the difference between the end caps  300  of  FIG.  72    and  FIG.  68    is the forms of the openings  320 . The opening  320  shown in  FIG.  68    is a circular opening. In the embodiment, the opening  320  shown in  FIG.  72    is an arc-shaped opening which is long and flat. The opening  320  shown in  FIG.  72    includes two opposite long edges  3201  (arc edges) and two opposite short edges  320   s  between the two long edges  3201 . The opening  320  has an interval “I” which is the shortest distance between the two long edges  3201 . Under the circumstances, the interval “I” of the opening  320  is much shorter than the length of the long edge  3201 . Even if the interval “I” of the opening  320  is equal to or slightly less than the diameter (i.e., the bore) of the opening  320  shown in  FIG.  68   , the bore area of the opening  320  shown in  FIG.  72    is still greater than that of the opening  320  shown in  FIG.  68   . As a result, the opening  320  of  FIG.  72    can not only prevent most of the dust from passing through but also improve ventilation. In an embodiment, the distance of the interval “I” of the opening is between 0.5 mm to 1.5 mm, and the length of the long edge  3201  of the opening is between 1 mm to 7 mm. 
     In different embodiments, the number, the shape, the position, or the arrangement of the opening(s)  320  can be varied according to different designs. Details are described below. 
     Referring to  FIG.  73   , the difference between the end caps  300  of  FIG.  73    and  FIG.  72    is the amount and forms of the openings  320 . In the embodiment, there are two openings  320  shown in  FIG.  73   , and the two openings  320  are substantially symmetrical to each other. The two symmetrical openings  320  shown in  FIG.  73    are beneficial to convection of heated air and cool air. The better the convection is, the better the effect of heat dissipation is. 
     Referring to  FIG.  74   , the difference between the end caps  300  of  FIG.  74    and  FIG.  72    is the amount and forms of the openings  320 . In the embodiment, there are two openings  320  shown in  FIG.  74   , and the two openings  320  are adjacent to each other. Under the circumstances that the interval between the two long edges of either opening  320  shown in  FIG.  74    is substantially equal to that of the opening  320  shown in  FIG.  72   , the sum of the bore areas of the two adjacent openings  320  shown in  FIG.  74    is greater than the bore area of the single opening  320  shown in  FIG.  72   . The two adjacent openings  320  shown in  FIG.  74    are not only beneficial to convection but also beneficial to prevent most of the dust from passing through the opening  320  and entering the end cap  300 . 
     Referring to  FIG.  75   , the difference between the end caps  300  of  FIG.  75    and  FIG.  74    is the amount and forms of the openings  320 . In the embodiment, there are two set of two openings  320  shown in  FIG.  75   , and the two set of two openings  320  are symmetrical to each other. The two set of two openings  320  shown in  FIG.  75    are not only beneficial to convection of heated air and cool air but also beneficial to prevent dust from passing through the opening  320  and entering the end cap  300 . 
     Referring to  FIG.  76   , the difference between the end caps  300  of  FIG.  76    and  FIG.  74    is the forms of the openings  320 . The two short edges opposite to each other of each opening  320  shown in  FIG.  9    are round. In the embodiment, the two short edges opposite to each other of each opening  320  shown in  FIG.  76    are rectangular. Referring to  FIG.  77   , the difference between the end caps  300  of  FIG.  77    and  FIG.  10    is the forms of the openings  320 . The two short edges opposite to each other of each opening  320  shown in  FIG.  10    are round. In the embodiment, the two short edges opposite to each other of each opening  320  shown in  FIG.  77    are rectangular. In different embodiments, the opening  320  can be a long, narrow and straight shaped opening. 
     Referring to  FIG.  78   , the difference between the end caps  300  of  FIG.  78    and  FIG.  3    is the amount and forms of the openings  320 . In the embodiment, the end cap  300  shown in  FIG.  78    comprises several openings  320 . The openings  320  are a plurality of circular shaped openings and are asymmetrically arranged on the end wall  302 . Referring to  FIG.  3    and  FIG.  78   , when the LED tube lamp  50  is installed to the horizontal lamp base, the axial directions of the tube  100  and the end cap  300  are substantially parallel with the horizontal direction “H”, and the altitude of at least one of the openings  320  shown in  FIG.  78    is higher than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V”. In the embodiment, the altitudes of all of the openings  320  shown in  FIG.  78    are higher than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V”. In different embodiments, the openings  320  symmetrically arranged on the end wall  302  have different shapes, e.g., a long, circular shape. Moreover, at least a part of at least one of the openings  320  is higher than the axle of the tube  100  and the end cap  300  in the vertical direction “V”. 
     Referring to  FIG.  79   , the difference between the end caps  300  of  FIG.  79    and  FIG.  78    is the amount, arrangement, and forms of the openings  320 . In the embodiment, the end cap  300  shown in  FIG.  79    comprises several openings  320 , and the openings  320  relative to the axle of the end cap  300  are symmetrical. The openings  320  are arranged on the end wall  302  and are around the axle of the end cap  300  in point symmetry. 
     Referring to  FIG.  80   , the differences between the LED tube lamps  50  of FIG.  80  and  FIG.  4    are the forms of the power supply  400  and the opening  320 . The power supply  400  shown in  FIG.  80    comprises a printed circuit board  420  and one or more electronic components  430 . The printed circuit board  420  comprises a first surface  421  and a second surface  422  opposite to and substantially parallel with each other. The first surface  421  and the second surface  422  of the printed circuit board  420  are perpendicular to the axial direction of the lateral wall  304 . The second surface  422  of the printed circuit board  420  relative to the first surface  421  is closer to the end wall  302  of the end cap  300  which at least part of the power supply  400  is inside. The electronic components  430  are disposed on the first surface  421  of the printed circuit board  420 . The electronic components  430  can be, for example, capacitors. 
     In the embodiment, as shown in  FIG.  80   , the second surface  422  of the printed circuit board  420  contacts the inner surface of the end wall  302 . Moreover, the metal wires  410  (not shown in  FIG.  80   ) of the power supply  400  can be directly inserted in the hollow conductive pins  301  from the printed circuit board  420 . Alternatively, the hollow conductive pins  301  can be directly contacted by a pair of corresponding contacts (not shown) on the second surface  422  of the printed circuit board  420 . In addition, the freely extending end portion  210  is connected to the first surface  421  of the printed circuit board  420 . In different embodiments, the second surface  422  of the printed circuit board  420  does not contact the inner surface of the end wall  302  and instead the second surface  422  of the printed circuit board  420  is spaced from the inner surface of the end wall  302  by a predetermined interval. The interval between the printed circuit board  420  and the end wall  302  is beneficial to convection of air. In addition, the freely extending end portion  210  is connected to the second surface  422  of the printed circuit board  420  (not shown). 
     In the embodiment, as shown in  FIG.  80   , the second surface  422  of the printed circuit board  420  fully contacts the inner surface of the end wall  302  and covers the opening  320 ; therefore, heat generated by the printed circuit board  420  can be directly transferred to cool air outside the end cap  300  through the opening  320  and, consequently, the effect of heat dissipation is improved. Furthermore, under the circumstances that the second surface  422  of the printed circuit board  420  fully covers the opening  320 , dust is blocked by the printed circuit board  420  so that dust won&#39;t pass through the opening  320  to enter the inner space of the end cap  300 . Thus, the bore area of the opening  320  shown in  FIG.  80    can be greater than that of the opening  320  shown in  FIG.  4   . 
     In different embodiments, the second surface  422  of the printed circuit board  420  contacts the inner surface of the end wall  302  while the end cap  300  has no opening  320 . In the situation, the end wall  302  can comprise a material with high thermal conductivity. The end wall  302 , for example, can be made by composite materials. The part of the end wall  320  which is connected to the hollow conductive pins  301  is made by an insulating material, and the other part of the end wall  320  is made by aluminum. Heat generated by the printed circuit board  420  can be directly transferred to the part of aluminum of the end wall  302  and then can be transferred to cool air outside the end cap  300  through the part of Aluminum; therefore, the effect of heat dissipation is improved. In different embodiments, the opening  320  can be disposed on the lateral wall  304  such that when the LED tube lamp  50  is installed to the horizontal lamp base, the altitude of the opening  320  on the lateral wall  304  is higher than that of the axle of the tube  100  and the end cap  300  in the vertical direction “V”. 
     Referring to  FIG.  81   , the difference between the LED tube lamps  50  of  FIG.  81    and  FIG.  80    is that the power supply  400  shown in  FIG.  81    further comprises a heat-dissipating element or a driving module  440 . The heat-dissipating element or driving module  440  is disposed on the second surface  422  of the printed circuit board  420  and extends into the opening  320 . In an embodiment, the heat-dissipating element  440   a  is a metal heat pipe or a metal fin. Heat generated by electronic components  430  on the printed circuit board  420  can be transferred to the heat-dissipating element  440   a  and then can be transferred to cool air outside the end cap  300  through the heat-dissipating element  440   a ; therefore; therefore, the effect of heat dissipation is improved. Since the driving module  440   b  is a main heat source among the electronic components of the power supply  400 , the idea of separation of the general electronic components  430  (the general electronic components  430  generating less heat than the driving module  440   b ) and the driving module  440   b  is beneficial to improve the effect of heat dissipation. For example, the general electronic components  430  are disposed on the first surface  421  of the printed circuit board  420  and the driving module  440   b  generating significant heat is disposed on the second surface  422  of the printed circuit board  420  and locates adjacently to the at least one opening  320 . The heat-dissipating element or driving module  440  can be disposed in the opening  320  such that the heat generated by the driving module  440   b  or the heat of heat-dissipating element can be directly transferred to cool air outside the end cap  300 ; therefore, the effect of heat dissipation is improved. The driving module  440   b  comprises one or more specific electronic components generating significant heat including an inductor, a transistor, or an integrated circuit. The arrangement of having the inductor, the transistor, or the integrated circuit positioned in the opening  320  is beneficial to improve the effect of heat dissipation. 
     In different embodiments, several heat-dissipating elements or driving modules  440  of the power supply  400  can be respectively disposed in several openings  320 . For example, the inductor, the transistor, and the integrated circuit can be respectively disposed in different openings  320 . Alternatively, the heat-dissipating element, the inductor, the transistor, and the integrated circuit can be respectively disposed in different openings  320 . 
     Referring to  FIG.  81    and  FIG.  82   , the difference between  FIG.  81    and  FIG.  82    is whether the heat-dissipating element or driving module  440  and the opening  320  are sealed in the radial direction of the opening  320 . The heat-dissipating element or driving module  440  (the heat-dissipating element  440   a  in the example) and the opening  320  shown in  FIG.  81    are sealed, which means that the shape and the size of the cross section of the heat-dissipating element or driving module  440  in the radial direction exactly match the shape and the size of the bore of the opening  320  in the radial direction. In one embodiment, at least one component of the heat-dissipating element or the driving module  440  and the at least one opening  320  are substantially sealed in the radial direction of the at least one opening. Instead, there is a gap “G” between the heat-dissipating element or driving module  440  (the driving module  440   b  in the example) and the opening  320  in the radial direction shown in  FIG.  82   . Thus, the outside air can freely flow through the gap “G” to enter the end cap  300  while the heat-dissipating element or driving module  440  is in the opening  320 . The effect that the heat-dissipating element or driving module  440  and the opening  320  are sealed in the radial direction is. In some embodiments, the sealed effect is not required to be the same as the effect of air tight sealing. There may be small gaps hard to be seen by eyes but still exist between the heat-dissipating element or driving module  440  and the opening  320  shown in  FIG.  81   . However, the small gaps between the heat-dissipating element or driving module  440  and the opening  320  shown in  FIG.  81    is much smaller than the gap “G” shown in  FIG.  82    and, consequently, the heat-dissipating element or driving module  440  and the opening  320  shown in  FIG.  81    block cool air outside the opening  320  to a great extent. 
     Referring to  FIG.  83   , the differences between the LED tube lamps  50  of  FIG.  83    and  FIG.  4    are the forms of the power supply  400 . The power supply  400  shown in  FIG.  83    comprises a printed circuit board  420 , one or more electronic components  430 , and a heat-dissipating element or driving module  440 . The printed circuit board  420  comprises a first surface  421  and a second surface  422  opposite to and substantially parallel with each other. The first surface  421  and the second surface  422  of the printed circuit board  420  are substantially parallel with the axial direction of the lateral wall  304 . The electronic components  430  and the heat-dissipating element or driving module  440  (the driving module  440   b  in the example) are all disposed on the first surface  421  of the printed circuit board  420 . The heat-dissipating element or driving module  440  relative to the electronic components  430  is closer to the opening  320 . In an embodiment, the heat-dissipating element  440   a  is a metal heat pipe or a metal fin. Heat generated by the printed circuit board  420  can be transferred to the heat-dissipating element  440   a . Since the heat-dissipating element  440   a  relative to the electronic components  430  is closer to the opening  320 , it is beneficial to heat exchange between the heat-dissipating element  440   a  and outside cool air, and, consequently, the effect of heat dissipation is better. In an embodiment, the driving module  440   b  relative to the electronic components  430  (the general electronic components generating less heat than the driving module  440   b ) is closer to the opening  320 , which is beneficial to heat exchange between the driving module  440   b  and outside cool air. Thus, the effect of heat dissipation is better. The driving module  440   b  comprises one or more specific electronic components generating significant heat. The specific electronic components includes an inductor, a transistor, or an integrated circuit. The arrangement that the inductor, the transistor, or the integrated circuit relative to the general electronic components  430  is closer to the opening  320  is beneficial to improve the effect of heat dissipation. 
     Referring to  FIG.  84   ,  FIG.  84    is a part of a cross section of the LED tube lamp  50  installed to a lamp base  1060 . The LED tube lamp  50  shown in  FIG.  84    comprises a coupling structure. A part of the coupling structure is disposed on the rear end region  101  of the tube  100 , and the other part of the coupling structure is disposed on the end cap  300 . The tube  100  and the end cap  300  can be connected to each other by the coupling structure. The coupling structure comprises a first thread  3001  disposed on the lateral wall  304  and a second thread  1001  disposed on the rear end region  101  of the tube  100 . The first thread  3001  is on the inner surface of the lateral wall  304  and is at an end of the lateral wall  304  away from the end wall  302 . The second thread  1001  is on the outer surface of the rear end region  101  of the tube  100  and is close to the open end of the tube  100  (i.e., the two opposite ends of the tube  100 ). The first thread  3001  is corresponding to the second thread  1001 . The end cap  300  can be connected to the tube  100  by relative rotation of the first thread  3001  and the second thread  1001 . Based on the coupling structure, the end cap  300  can be easily assembled to the tube  100  or disassembled from the tube  100 . 
     As shown in  FIG.  84   , in the embodiment, when the relative rotation of the first thread  3001  and the second thread  1001  is done and the first thread  3001  fully matches the second thread  1001  (i.e., the end cap  300  is properly assembled to the tube  100 ), the opening  320  is rotated about the axle of the tube  100  to a predetermined position. Specifically, while the lamp base  1060  is horizontal or substantially horizontal and the LED tube lamp  50  is horizontally installed to the lamp base  1060 , the axial directions of the tube  100  and the end cap  300  are substantially parallel with the horizontal direction “H”, and the predetermined position means that the altitude of the opening  320  is higher than that of the axle of the lateral wall  302  in the vertical direction “V” in the configuration. 
     As shown in  FIG.  84   , in the embodiment, the coupling structure further comprises a first positioning unit  3002  disposed on the lateral wall  304  and a second positioning unit  1002  disposed on the rear end region  101  of the tube  100 . The first positioning unit  3002  is corresponding to the second positioning unit  1002 . When the relative rotation of the first thread  3001  and the second thread  1001  is done and the first thread  3001  fully matches the second thread  1001 , the first positioning unit  3002  mates the second positioning unit  1002 , such that the tube  100  and the end cap  300  are positioned to each other. In the embodiment, the first positioning unit  3002  is a concave point on the inner surface of the lateral wall  304 , and the second positioning unit  1002  is a convex point on the outer surface of the rear end region  101  of the tube  100 . When the first thread  3001  fully matches the second thread  1001 , the convex point of the second positioning unit  1002  falls in the concave point of the first positioning unit  3002  to assist the fixation of the LED tube lamp  50  and to inform people assembling the LED tube lamp  50  that the end cap  300  has been properly assembled to the tube  100 . More particularly, when the first positioning unit  3002  and the second positioning unit  1002  are coupled to each other along with slightly sound and vibration, people assembling the LED tube lamp  50  can be informed by hearing the sound or feeling the vibration and can immediately realize that the end cap  300  has been properly assembled to the tube  100 . In the assembling process of the LED tube lamp  50 , operator, based on the sound and the vibration generated by the mating (coupling) of the first positioning unit  3002  and the second positioning unit  1002 , can finish the assembling process of an assembled LED tube lamp  50  in time. Thus, the efficiency of assembling can be improved. 
     In different embodiments, the first positioning unit  3002  can be a convex point, and the second positioning unit  1002  can be a concave point. In different embodiments, the first positioning unit  3002  and the second positioning unit  1002  can respectively be disposed on different positions of the end cap  300  and the rear end region  101  of the tube  100  on the premise that the first positioning unit  3002  mates the second positioning unit  1002  only when the end cap  300  is properly assembled to the tube  100 . 
     As shown in  FIG.  84   , the method of having the LED tube lamp  50  installed to the lamp base  1060  is: plugging the hollow conductive pins  301  of the end cap  300  into the conductive sockets  61  of the lamp base  1060 , and rotating the LED tube lamp  50  about the axle of the tube  100  and the end cap  300  until the hollow conductive pins  301  in the conductive sockets  61  are rotated to a predetermined position. The assembling is done when the hollow conductive pins  301  in the conductive sockets  61  are in the predetermined position. 
     In the embodiment, torque applied to the tube  100  and the end cap  300  to have the first thread  3001  and the second thread  1001  relatively rotated until the first thread  3001  fully matches the second thread  1001  is greater than that applied to the LED tube lamp  50  to have the LED tube lamp  50  installed to the lamp base  1060  (i.e., torque for rotating the hollow conductive pins  301  in the conductive sockets  61 ). In other words, friction force between the first thread  3001  and the second thread  1001  of the assembled LED tube lamp  50  is greater than that between the hollow conductive pins  301  and the conductive sockets  61  when the LED tube lamp  50  is installed to the lamp base  1060 . In an embodiment, the friction force between the first thread  3001  and the second thread  1001  is at least twice greater than that between the hollow conductive pins  301  and the conductive sockets  61 . When the installed LED tube lamp  50  is going to be uninstalled from the lamp base  1060 , the hollow conductive pins  301  in the conductive sockets  61  have to be reversely rotated to a predetermined position in advance, and then the LED tube lamp  50  can be unplugged from the lamp base  1060  (i.e., the hollow conductive pins  301  can be unplugged from the conductive sockets  61 ). Since the friction force between the first thread  3001  and the second thread  1001  is greater than that between the hollow conductive pins  301  and the conductive sockets  61 , the relative position of the first thread  3001  and the second thread  1001  remains still during the reverse rotation of the hollow conductive pins  301  in the conductive sockets  61 . As a result, the end cap  300  won&#39;t accidentally loose from the tube  100  during the process of uninstalling the LED tube lamp  50  from the lamp base  1060 . 
     Referring to  FIG.  85   ,  FIG.  85    is a part of a cross section of the LED tube lamp  50  installed to the lamp base  1060 , the difference between the LED tube lamps  50  of the  FIG.  85    and  FIG.  84    is with respect to the coupling structures. As shown in  FIG.  85   , the coupling structure comprises an annular convex portion  3003  disposed on the lateral wall  304  and an annular trough  1003  disposed on the rear end region  101  of the tube  100 . The annular convex portion  3003  is on the inner surface of the lateral wall  304  and is at an end of the lateral wall  304  away from the end wall  302 . The annular trough  1003  is on the outer surface of the rear end region  101  of the tube  100 . The annular convex portion  3003  is corresponding to the annular trough  1003 . The end cap  300  can be connected to the tube  100  by the coupling of the annular convex portion  3003  and the annular trough  1003 . The annular convex portion  3003  and the annular trough  1003  are rotatably connected to each other. More particularly, the annular convex portion  3003  is capable of sliding along the annular trough  1003 , and, consequently, the tube  100  and the end cap  300  have a degree of freedom capable of rotating relative to each other about the axle of the tube  100  and the end cap  300  by the annular convex portion  3003  and the annular trough  1003 . 
     As shown in  FIG.  85   , in the embodiment, the coupling structure further comprises a first positioning unit  3002  disposed on the lateral wall  304  and a second positioning unit  1002  disposed on the rear end region  101  of the tube  100 . The structure and the function of the first positioning unit  3002  and the second positioning unit  1002  are described above and there is no need to repeat. Although the tube  100  and the end cap  300  are rotatably connected to each other by the coupling of the annular convex portion  3003  and the annular trough  1003 , the first positioning unit  3002  mates the second positioning unit  1002  (e.g., the concave point of the first positioning unit  3002  and the convex point of the second positioning unit  1002  are coupled to each other) when the tube  100  and the end cap  300  are rotated relative to each other to a predetermined position to assist the positioning in the assembling process of the tube  100  and the end cap  300  and to enhance the fixation of the tube  100  and the end cap  300 . Based on the coupling structure, the end cap  300  can be easily assembled to the tube  100  or disassembled from the tube  100 . 
     As shown in  FIG.  85   , in the embodiment, the rear end regions  101  of the tube  100  utilized for being connected to the end cap  300  is shrunk in the radial direction. The extent that the rear end regions  101  shrunk (i.e., difference between the main body region  102  and the rear end regions  101  in radial direction) is equivalent to the thickness of the lateral wall  304  of the end cap  300 . Thus, the outer surface of the lateral wall  304  of the end cap  300  is aligned with the outer surface of the main body region  102  of the tube  100  while the end cap  300  and the tube  100  are connected to each other. 
     In different embodiments, the annular trough  1003  can be disposed on the lateral wall  304 , and the annular convex portion  3003  can be disposed on the rear end region  101  of the tube  100 . Additionally, the coupling structure can further comprise a hot melt adhesive. The hot melt adhesive can be disposed in the joint of the tube  100  and the end cap  300  (e.g., between the rear end region  101  and the lateral wall  304 ). When assembling the tube  100  and the end cap  300 , the end cap  300  can be assembled to the tube  100  via the coupling structure in advance, and the hot melt adhesive is in liquid state in the assembling process. After heating up the hot melt adhesive, and upon expansion due to heat absorption, the hot melt adhesive flows, and then solidifies upon cooling, thereby bonding together the end cap  300  to the tube  100  (not shown). The volume of the hot melt adhesive may expand to about 1.3 times the original size when heated from room temperature (e.g., between about 15 and 30 degrees Celsius) to about 200 to 250 degrees Celsius. The end cap  300  and the end of the tube  100  could be secured by using the hot melt adhesive and therefore qualified in a torque test of about 1.5 to about 5 newton-meters (Nt-m) and/or in a bending test of about 5 to about 10 newton-meters (Nt-m). During the heating and solidification of the hot melt adhesive, the heat and pressure inside the end cap increase and are then released through the at least one opening  320  on the end cap  300 . After the hot melt adhesive hardens, the end cap  300  can be firmly fixed to the tube  100 . Under the circumstances, the end cap  300  and the tube  100  is hard to disassemble unless the hardened hot melt adhesive returns to liquid state by certain process. The design of the LED tube lamp  50  is to take into account both the convenience regarding the assembling process of the LED tube lamp  50  and the robustness regarding the assembled LED tube lamp  50 . 
     Referring to  FIG.  86   ,  FIG.  86    is a perspective view of the LED tube lamp  50  installed to an inclined lamp base  1060 . In different embodiments, the LED tube lamp  50  can be installed to an inclined or a vertical lamp base  1060  in an inclined or vertical pose. In the embodiment, as shown in  FIG.  86   , the lamp base  1060  is inclined. Thus, the axle of the LED tube lamp  50  and the horizontal direction “H” define an acute angle while the LED tube lamp  50  is installed to the lamp base  1060 . Under the circumstances that the LED tube lamp  50  installed to the lamp base  1060  is inclined, the altitude of the opening  320  of the end cap  300  is still higher than that of the axle of the LED tube lamp  50  in the vertical direction “V”, which is beneficial to improve the effect of heat dissipation. 
     Referring to  FIGS.  87 ,  88  and  89   ,  FIG.  87    is a partial view of the LED tube lamp  50 ,  FIG.  88    is a cross section of  FIG.  87    along the line B-B′, and  FIG.  89    is a partially cross section of  FIG.  87   . Wherein a part of components of the end cap  300  is not shown in  FIG.  89   . The difference between the end cap  300  of  FIGS.  87  to  89    and the end cap  300  of  FIG.  68    is the forms of the openings  320 . Additionally, the end cap  300  of  FIGS.  87  to  89    further comprises two vertical ribs  330 , and the vertical ribs  330  are utilized for fixation of the printed circuit board  420  of the power supply  400 . Thus, the relative position between the printed circuit board  420  of the power supply  400  and the end cap  300  of  FIGS.  87  to  89    can be varied based on the shape of the vertical ribs  300 . 
     As shown in  FIG.  87   , in the embodiment, the opening  320  has a bow-shaped opening. The size and the position of the opening  320  are corresponding to the two vertical ribs  330 . That is to say, the two vertical ribs can be seen from outside the opening  320  in the viewing angle which is substantially parallel with and is along the axial direction of the end cap  300 . Furthermore, the two vertical ribs  330  are disposed on the inner surface of the lateral wall  304 , and the two vertical ribs are spaced from each other and extend along the axial direction of the lateral wall  304 . The vertical ribs  330  are perpendicular to a plane at which the printed circuit board  420  of the power supply  400  is located. In other words, the two vertical ribs  330  are perpendicular to a side of the printed circuit board  420  of the power supply  400  in the radial direction of the end cap  300 . For illustration, as shown in  FIG.  88   , when the LED tube lamp  50  is horizontally installed, the axial directions of the end cap  300  is substantially parallel with the horizontal direction “H”, and the vertical ribs  300  extend from the inner surface of the lateral wall  304  along the vertical direction “V” and is connected to the printed circuit board  420  of the power supply  400 . 
     As shown in  FIG.  88    and  FIG.  89   , the vertical rib  330  comprises a first side  331 , a second side  332 , and a third side  333 . The first side  331  and the second side  332  are opposite to each other. The second side  332  relative to the first side  331  is closer to the opening  320 . The third side  333  is away from the lateral wall  304  and is between the first side  331  and the second side  332 . The third side  333  is connected to the printed circuit board  420  of the power supply  400 . The third side  333  is, but is not limited to, adhered to or coupled to the printed circuit board  420  of the power supply  400 . 
     In the embodiment, as shown in  FIGS.  87  to  89   , the shortest distance between the third side  333  of the vertical rib  330  and the lateral wall  304  gradually decreases along the axial direction of the lateral wall  304  towards the end wall  302 . For illustration, as shown in  FIG.  88   , the height of any point of the vertical rib  330  along the horizontal direction “H” relative to the lateral wall  304  in the vertical direction “V” is the shortest distance between the third side  333  of the vertical rib  330  and the lateral wall  304 . The height of the vertical rib  330  gradually decreases along the axial direction of the lateral wall  304  towards the end wall  302 . That is to say, the height of the vertical rib  330  relative to the lateral wall  304  gradually decreases from the first side  331  to the second side  332 . Thus, an extending direction of the third side  333  and the axial direction of the end cap  300  define an acute angle, and, consequently, the printed circuit board  420  of the power supply  400  connected to the third side  333  is inclined. For illustration, as shown in  FIG.  88   , the altitude of one side of the printed circuit board  420  of the power supply  400  close to the end wall  302  is different from that of the other side of the printed circuit board  420  of the power supply  400  away from the end wall  302  in the vertical direction “V”. The altitude of the side of the printed circuit board  420  of the power supply  400  close to the end wall  302  is higher than that of the other side of the printed circuit board  420  of the power supply  400  away from the end wall  302 . The side of the printed circuit board  420  of the power supply  400  close to the end wall  302  relative to the other side of the printed circuit board  420  of the power supply  400  is closer to the opening  320 . Under the circumstances, heated air generated by the power supply  400  can rise along the inclined power supply  400  and flow through the opening  320  to outside area of the end cap  300 , which is beneficial to improve the effect of heat dissipation. 
     Referring to  FIG.  90   , the difference between the end cap  300  of  FIG.  90    and the end cap  300  of  FIGS.  87  to  89    is the forms of the vertical ribs  330 . The shortest distance between the third side  333  of the vertical rib  330  shown in  FIG.  90    and the lateral wall  304  gradually increases along the axial direction of the lateral wall  304  towards the end wall  302 . That is to say, the height of the vertical rib  330  relative to the lateral wall  304  gradually increases from the first side  331  to the second side  332 . Under the circumstances, the altitude of one side of the printed circuit board  420  of the power supply  400  connected to the third side  333  of the vertical rib  330  close to the end wall  302  is lower than that of the other side of the printed circuit board  420  of the power supply  400  away from the end wall  302 . The configuration of the vertical ribs  330  and the printed circuit board  420  of the power supply  400  shown in  FIG.  90    is beneficial to convection of inside heated air and outside cool air since outside cool air can easily enter the inner space of the end cap  300 . 
     Referring to  FIG.  91   , the difference between the end cap  300  of  FIG.  91    and the end cap  300  of  FIGS.  87  to  89    is the forms of the vertical ribs  330 . In addition, the power supply  400  shown in  FIG.  91    further comprises a printed circuit board  420 . In different embodiments, the power supply  400  can further comprise a power module disposed on the printed circuit board  420  or can further comprise one or more electronic components  430  and one or more heat-dissipating elements or driving modules  440  disposed on the printed circuit board  420 . In different embodiments, the power supply  400  can be a module, e.g., an integrated power module integrated with the printed circuit board  420  and electronic components. 
     As shown in  FIG.  91   , in the embodiment, the power supply  400  further comprises electronic components  430  and a heat-dissipating element or driving module  440  disposed on the printed circuit board  420 . Specifically, the printed circuit board  420  comprises a first surface  421  and a second surface  422  opposite to each other. The electronic components  430  and the heat-dissipating element or driving module  440  are disposed on the first surface  421 . The second surface  422  is connected to the third sides  333  of the vertical ribs  330 . In the embodiment, the height of the vertical rib  330  relative to the lateral wall  304  from the first side  331  to the second side  332  is identical, and, consequently, the printed circuit board  420  connected to the third side  333  is horizontal but not inclined. The heat-dissipating element or driving module  440  can be a heat-dissipating element, an inductor, a transistor, or an integrated circuit. The heat-dissipating element or driving module  440  relative to the electronic components  430  is closer to the opening  320 . In addition, the second surface  422  of the printed circuit board  420  is spaced from the lateral wall  304  by a certain interval based on the vertical ribs  330 . An extending direction of the vertical rib  330  from the first side  331  to the second side  332  is towards the opening  320 . As a result, there is a space for convection of air between the power supply  400  and the lateral wall  304 , and heated air can easily flow through the opening  320  to outside area of the end cap  300 . 
     Referring to  FIGS.  92  to  94   ,  FIG.  92    is an end view of the LED tube lamp  50  in which the viewing angle is substantially parallel with the axle of the end cap  300 ,  FIG.  93    is a radial cross section of the end cap  300  of  FIG.  92   , and  FIG.  94    is a part of an axial cross section of  FIG.  92    along the line C-C′. The difference between the end caps  300  between  FIGS.  92  to  94    and  FIG.  91    is that the end cap  300  shown in  FIGS.  92  to  94    further comprises two horizontal ribs  340 , and the power supply  400  shown in  FIGS.  92  to  94    is a power module. 
     The opening  320  is the bow-shaped opening, as described above. The size and the position of the opening  320  are corresponding to the two vertical ribs  330 . More particularly, a projection of the two vertical ribs  330  is inside a projection of the opening  320  on a plane of projection perpendicular to the axial direction of the end cap  300 . In other words, as shown in  FIG.  92   , the two vertical ribs can be seen from outside the opening  320  when seeing into the opening  320  along the axial direction of the end cap  300 . As a result, the space for convection between the two vertical ribs  330  and power supply  400  is corresponding to the opening  320  which is beneficial to improve the effect of heat dissipation. 
     In the embodiment, as shown in  FIGS.  92  to  94   , the two horizontal ribs  340  are disposed on the inner surface of the lateral wall  304 , and the two horizontal ribs  340  are spaced from each other and extend along the axial direction of the lateral wall  304 . Each of the horizontal ribs  340  has a long and flat shape. The two horizontal ribs  340  are opposite to each other and are symmetric. The two horizontal ribs  340  are respectively corresponding to the two vertical ribs  330 . The printed circuit board  420  of the power supply  400  is sandwiched between the vertical ribs  330  and the horizontal ribs  340 . In other words, one side of the printed circuit board  420  of the power supply  400  is connected to the vertical ribs  330 , and the other side of the printed circuit board  420  of the power supply  400  is connected to the horizontal ribs  340 . The collaboration of the vertical ribs  330  and the horizontal ribs  340  can firmly clamp and fix the printed circuit board  420  of the power supply  400 . 
     Referring to  FIG.  95   , the difference between the end caps  300  of  FIG.  95    and  FIG.  94    is that the horizontal rib  340  shown in  FIG.  94    is a whole piece and instead, the horizontal rib  340  shown in  FIG.  95    has a cut portion. More particularly, the horizontal rib  340  shown in  FIG.  95    comprises a first rib portion  341 , a second rib portion  342 , and a cut portion  343 . The cut portion  343  is between the first rib portion  341  and the second rib portion  342 . That is to say, the first rib portion  341  and the second rib portion  342  are spaced from each other by the cut portion  343 . The cut portion  343  can be utilized for convection of air and is beneficial to improve the effect of heat dissipation. 
     In addition, the difference between the end caps  300  of  FIG.  95    and  FIG.  94    is that the end cap  300  shown in  FIG.  95    further comprises a blocking plate  350 . The blocking plate  350  is disposed on the inner surface of the lateral wall  304 . The blocking plate  350  and the end wall  302  are spaced from each other in the axial direction of the lateral wall  304 . A side of the printed circuit board  420  of the power supply  400  facing towards the end wall  302  contacts the blocking plate  350 . The printed circuit board  420  of the power supply  400  is spaced from the end wall  302  by the blocking plate  350  such that there is a gap between the printed circuit board  420  of the power supply  400  and the end wall  302  in the axial direction of the lateral wall  304 . The gap can be utilized for convection of air and is beneficial to improve the effect of heat dissipation. 
     Referring to  FIG.  96   , the difference between the end caps  300  of  FIG.  96    and  FIG.  94    is that the horizontal rib  340  shown in  FIG.  94    is a whole piece and instead, the horizontal rib  340  shown in  FIG.  96    comprises one or more through holes. More particularly, each of the horizontal ribs  340  shown in  FIG.  96    comprises a plurality of ventilating holes  344 . The ventilating hole  344  penetrates through the horizontal rib  340  and the ventilating holes  344  are arranged on the horizontal rib  340 . The ventilating holes  344  can be utilized for convection of air and is beneficial to improve the effect of heat dissipation. 
     Referring to  FIG.  97   , the difference between the LED tube lamps  50  of  FIG.  97    and  FIGS.  66  to  69    is with respect to the relationship of the LED light strip  200  and the printed circuit board  420  of the power supply  400 . A plane at which the LED light strip  200  shown in  FIGS.  66  to  69    locates is substantially parallel with a plane at which the printed circuit board  420  of the power supply  400  locates. However, a plane at which the LED light strip  200  shown in  FIG.  97    locates is not parallel with a plane at which the printed circuit board  420  of the power supply  400  locates. More particularly, as shown in  FIG.  97   , the LED light strip  200  locates at a first plane P 1 , and the printed circuit board  420  of the power supply  400  locates at a second plane P 2 . The first plane P 1  and the second plane P 2  are substantially parallel with the axial direction of the tube  100 , and the first plane P 1  and the second plane P 2  define an angle θ 2  about the axial direction of the tube  100 . The angle θ 2  is greater than 0 degree and is less than 90 degrees. In other words, comparing to the printed circuit board  420  of the power supply  400  and the LED light strip  200  shown in  FIGS.  66  to  69   , the printed circuit board  420  of the power supply  400  shown in  FIG.  97    relative to the LED light strip  200  rotates about the axial direction of the tube  100  to the angle θ 2 . Based on the configuration that the plane at which the LED light strip  200  locates and the plane at which the printed circuit board  420  of the power supply  400  locates are not parallel with each other and instead intersect on a plane of projection along the axial direction of the tube  100 , the heated air heated by the LED light strip  200  and the LED light sources  202  can easily flow through the tube  100  to the end cap  300  so as to further flow through the opening  320  to outside area of the end cap  300 , which is beneficial to improve the effect of heat dissipation. 
     Referring to  FIG.  98   , the difference between the end caps  300  of  FIG.  98    and  FIGS.  66  to  69    is the forms of the openings  320 . The opening  320  shown in  FIG.  98    is, but is not limited to, at the center of the end wall  302 . In the assembling process of the LED tube lamp  50 , two end caps  300  have to be assembled to two ends of the tube  100 . After one of the two end caps  300  is assembled to one end of the tube  100 , it is more difficult to have the other end caps  300  assembled to the other end of the tube  100 . The reason is that if the inner space of the tube  100  and end caps  300  is sealed or is almost sealed, the pressure inside the tube  100  and end caps  300  increases along with compression of gas inside the tube  100  and end caps  300 . More strength is required to assemble the end cap  300  to the tube  100  to against the increased pressure inside the tube  100  and end caps  300 , which leads to difficulty of assembling. The opening  320  shown in  FIG.  98    can function as a pressure-releasing tunnel. Under the circumstances, gas inside the tube  100  and end caps  300  can be released through the opening  320  during the process of assembling the last one of the two end caps  300  to the tube  100 , such that the pressure inside the tube  100  and end caps  300  can be constant. It is beneficial to the assembling process of the LED tube lamp  50  and to improve the efficiency of assembling. On the other hand, if there is no opening on the end caps  300 , the pressure inside the tube  100  and the end caps  300  of the LED tube lamp  50  may become negative pressure resulting from the lowering of the temperature inside the tube  100  and the end caps  300 . The opening  320  functioning as the pressure-releasing tunnel also allows the outside gas capable of flowing into the tube  100  and the end caps  300  such that the pressure inside the tube  100  and the end caps  300  can remain constant (equal to the pressure outside the tube  100  and the end caps  300 ); therefore, during a disassembling process of the LED tube lamp  50 , the end cap  300  is easily to be disassembled from the tube  100 . 
     In addition, when the LED tube lamp  50  operates, the electronic components of the LED tube lamp  50  keep generating heat such that the temperature inside the LED tube lamp  50  increases. According to the equation of state of a hypothetical ideal gas, the result of multiplication of pressure and volume of gas inside the LED tube lamp  50  increases along with the increase of the temperature. If gas is sealed in the tube  100  and the end caps  300 , the volume of the gas is constant. Thus, the pressure increases along with the increase of the temperature. Under the circumstances, when the LED tube lamp  50  continuously operates, the electronic components continuously suffer high temperature and high pressure and, consequently, are easily damaged. The opening  320  shown in  FIG.  98    can function as a pressure-releasing tunnel. In other words, the expanding gas can be released from the opening  320  when the temperature of the gas inside the LED tube lamp  50  increases, which is beneficial to decrease the pressure inside the LED tube lamp  50 . 
     Referring to  FIG.  99   ,  FIG.  99    is a part of a cross section of  FIG.  98    along the line D-D′. The difference between  FIG.  99    and  FIG.  98    is that the LED tube lamp  50  shown in  FIG.  99    further comprises a light sensor  450  and a circuit safety switch (not shown). In the embodiment, the light sensor  450  and the circuit safety switch are, but are not limited to, disposed on the printed circuit board  420  of the power supply  400  and are electrically connected to the printed circuit board  420  of the power supply  400 . Moreover, the power supply  400  can comprise a built-in electricity source. For example, the power supply  400  can comprise a mini battery; therefore, the power supply  400  can be supplied by the mini battery so as to supply the operation of the light sensor  450  and the circuit safety switch before the LED tube lamp  50  is installed to a lamp base. The circuit safety switch is integrated in the power supply  400 . The light sensor  450  is positioned corresponding to the opening  320 , and the light sensor  450  is collimated with the opening  320 . In different embodiments, the light sensor  450  does not extend into the opening  320 . Alternatively, the light sensor  450  can extend into the opening  320 . The light sensor  450  can sense light inside the opening  320  or ambient light outside the opening  320  but near the end wall  302 . Furthermore, the light sensor  450  can generate sensing signals according to the intensity of the sensed light (e.g., brightness). The sensing signals are transmitted to the circuit safety switch. The circuit safety switch determines whether to close or to open the circuit of the power supply  400  based on the received sensing signals. 
     How the light sensor  450  and the circuit safety switch work are described below and the description is merely an example but not a limitation. When the brightness sensed by either one of the light sensors  450  of the end caps  300  is greater than a predetermined threshold, the circuit safety switch opens the circuit of the power supply  400 . When the brightness sensed by both of the light sensors  450  of the end caps  300  are less than the predetermined threshold, the circuit safety switch closes the circuit of the power supply  400 . 
     For instance, when a user holds the LED tube lamp  50  and is going to install the LED tube lamp  50  to the lamp base  1060  (referring to  FIGS.  84  to  86   ), the end caps  300  at two ends of the LED tube lamp  50  are exposed to the environment and do not obstructed by anything such that the brightness sensed by both of the light sensors  450  of the end caps  300  are greater than the predetermined threshold, the circuit safety switch opens the circuit of the power supply  400 . Next, when the user has the hollow conductive pins  301  of the end cap  300  of one end of the LED tube lamp  50  plugged into the conductive sockets  61  of one end of the lamp base  1060 , the light sensor  450  in the end cap  300  having been plugged into one end of the lamp base  1060  is obstructed by the lamp base  1060 , and, consequently, brightness sensed by the light sensor  450  is less than the predetermined threshold. However, brightness sensed by the light sensor  450  in the other end cap  300  which is not yet plugged into the conductive sockets  1061  is still greater than the predetermined threshold. In the situation, the circuit safety switch still has the circuit of the power supply  400  remain open. Thus, there is no risk of electric shock to the user. Finally, when the user properly install the LED tube lamp  50  to the lamp base  60 , both of the end caps  300  at two ends of the LED tube lamp  50  are obstructed by the lamp base  60 , and brightness sensed by both of the light sensors  450  of the two end caps  300  are less than the predetermined threshold. Under the circumstances that brightness sensed by both of the light sensors  450  of the two end caps  300  are less than the predetermined threshold, the circuit safety switch closes the circuit of the power supply  400 , and the power supply  400  of which the circuit is closed can receive electricity from the lamp base  60  and can supply the LED light strip  200  and the LED light source  202 . 
     According to the light sensors  450  and the circuit safety switches of the LED tube lamp  50  shown in  FIG.  99   , under the circumstances that the hollow conductive pins  301  of the end cap  300  of one end of the LED tube lamp  50  is plugged into the conductive sockets  61  of one end of the lamp base  60  and the hollow conductive pins  301  of the end cap  300  of the other end of the LED tube lamp  50  is still exposed to environment, the circuit safety switches automatically open the circuits of the power supply  400  (or have the circuits of the power supply  400  remain open). Thus, the user has no risk of electric shock even if the exposed hollow conductive pins  301  are contacted by the user. As a result, safety regarding the use of the LED tube lamp  50  can be ensured. 
     Referring to  FIG.  100    to  FIG.  103   ,  FIG.  100    is a perspective view of a LED light strip  200 , e.g., a bendable circuit sheet, and a printed circuit board  420  of a power supply  400  soldered to each other and  FIG.  101    to  FIG.  103    are diagrams of a soldering process of the LED light strip  200  and the printed circuit board  420  of the power supply  400 . In the embodiment, the LED light strip  200  and the freely extending end portions  210  have the same structure. The freely extending end portions  210  are the portions of two opposite ends of the LED light strip  200  and are utilized for being connected to the printed circuit board  420 . The LED light strip  200  and the power supply  400  are electrically connected to each other by soldering. Two opposite ends of the LED light strip  200  are utilized for being respectively soldered to the printed circuit board  420  of the power supply  400 . In other embodiments, only one end of the LED light strip  200  is soldered to the power supply  400 . The LED light strip  200  is, but not limited to, a bendable circuit sheet, and the LED light strip  200  comprises a circuit layer  200   a  and a circuit protecting layer  200   c  over a side of the circuit layer  200   a.    
     In one embodiment, the LED light strip  200  includes a bendable circuit sheet having a conductive wiring layer and a dielectric layer that are arranged in a stacked manner, wherein the wiring layer and the dielectric layer have same areas (not shown) or the wiring layer has less area than the dielectric layer. The LED light source  202  is disposed on one surface of the wiring layer, the dielectric layer is disposed on the other surface of the wiring layer that is away from the LED light sources  202 . The wiring layer is electrically connected to the power supply  400  to carry direct current (DC) signals. Meanwhile, the surface of the dielectric layer away from the wiring layer is fixed to the inner circumferential surface of the tube  100  by means of an adhesive sheet (not shown). The wiring layer can be a metal layer or a power supply layer including wires such as copper wires. 
     In another embodiment, the outer surface of the wiring layer or the dielectric layer may be covered with a circuit protective layer made of an ink that functions to resist soldering and increases reflectivity (not shown). Alternatively, the dielectric layer can be omitted and the wiring layer can be directly bonded to the inner circumferential surface of the tube  100 , and the outer surface of the wiring layer is coated with the circuit protective layer. Whether the wiring layer has a one-layered, or two-layered structure, the circuit protective layer can be adopted. In some embodiments, the circuit protective layer is disposed only on one side/surface of the LED light strip  200 , such as the surface having the LED light source  202 . In some embodiments, the bendable circuit sheet is a one-layered structure made of just one wiring layer, or a two-layered structure made of one wiring layer and one dielectric layer, and thus is more bendable or flexible to curl when compared with the conventional three-layered flexible substrate (one dielectric layer sandwiched with two wiring layers). As a result, the bendable circuit sheet of the LED light strip  200  can be installed in a tube with a customized shape or non-tubular shape, and fitly mounted to the inner surface of the tube  100 . The bendable circuit sheet closely mounted to the inner surface of the tube  100  is preferable in some cases. In addition, using fewer layers of the bendable circuit sheet improves the heat dissipation and lowers the material cost. 
     Nevertheless, the bendable circuit sheet is not limited to being one-layered or two-layered; in other embodiments, the bendable circuit sheet may include multiple layers of the wiring layers and multiple layers of the dielectric layers, in which the dielectric layers and the wiring layers are sequentially stacked in a staggered manner, respectively (not shown). These stacked layers are away from the surface of the outermost wiring layer which has the LED light source  202  disposed thereon and is electrically connected to the power supply  400 . Moreover, the length of the bendable circuit sheet is greater than the length of the tube  100 . 
     In one embodiment, the LED light strip  200  includes a bendable circuit sheet having in sequence a first wiring layer, a dielectric layer, and a second wiring layer. The thickness of the second wiring layer is greater than that of the first wiring layer, and the length of the LED light strip  200  is greater than that of the tube  100 . The end region of the light strip  200  extending beyond the end portion of the tube  100  without disposition of the light source  202  is formed with two separate through holes to respectively electrically communicate the first wiring layer and the second wiring layer. The two separate through holes are not communicated to each other to avoid short. 
     In this way, the greater thickness of the second wiring layer allows the second wiring layer to support the first wiring layer and the dielectric layer, and meanwhile allow the LED light strip  200  to be mounted onto the inner circumferential surface without being liable to shift or deform, and thus the yield rate of product can be improved. In addition, the first wiring layer and the second wiring layer are in electrical communication such that the circuit layout of the first wiring layer can be extended downward to the second wiring layer to reach the circuit layout of the entire LED light strip  200 . Moreover, since the land for the circuit layout becomes two-layered, the area of each single layer and therefore the width of the LED light strip  200  can be reduced such that more LED light strips  200  can be put on a production line to increase productivity. Furthermore, the first wiring layer and the second wiring layer of the end region of the LED light strip  200  that extends beyond the end portion of the tube  100  without disposition of the light source  202  can be used to accomplish the circuit layout of a power supply  400  so that the power supply  400  can be directly disposed on the bendable circuit sheet of the LED light strip  200 . 
     Moreover, the LED light strip  200  comprises two opposite surfaces which are a first surface  2001  and a second surface  2002 . The first surface  2001  is the one on the circuit layer  200   a  and away from the circuit protecting layer  200   c . The second surface  2002  is the other one on the circuit protecting layer  200   c  and away from the circuit layer  200   a . Several LED light sources  202  are disposed on the first surface  2001  and are electrically connected to circuits of the circuit layer  200   a . The circuit protecting layer  200   c  has less electrical and thermal conductivity but being beneficial to protect the circuits. The first surface  2001  of the LED light strip  200  comprises soldering pads “b”. Soldering material “g” can be placed on the soldering pads “b”. In the embodiment, the LED light strip  200  further comprises a notch “f”. The notch “f” is disposed on an edge of the end of the LED light strip  200  soldered to the printed circuit board  420  of the power supply  400 . The printed circuit board  420  comprises a power circuit layer  420   a  and soldering pads “a”. Moreover, the printed circuit board  420  comprises two opposite surfaces which are a first surface  421  and a second surface  422 . The second surface  422  is the one on the power circuit layer  420   a . The soldering pads “a” are respectively disposed on the first surface  421  and the second surface  422 . The soldering pads “a” on the first surface  421  are corresponding to those on the second surface  422 . Soldering material “g” can be placed on the soldering pad “a”. In the embodiment, considering the stability of soldering and the optimization of automatic process, the LED light strip  200  is disposed below the printed circuit board  420  (the direction is referred to  FIG.  101   ). That is to say, the first surface  2001  of the LED light strip  200  is connected to the second surface  422  of the printed circuit board  420 . 
     As shown in  FIG.  102    and  FIG.  103   , in the soldering process of the LED light strip  200  and the printed circuit board  420 , the circuit protecting layer  200   c  of the LED light strip  200  is placed on a supporting table  52  (i.e., the second surface  2002  of the LED light strip  200  contacts the supporting table  52 ) in advance. The soldering pads “a” on the second surface  422  of the printed circuit board  420  directly sufficiently contact the soldering pads “b” on the first surface  2001  of the LED light strip  200 . And then a thermo-compression heating head  51  presses on a portion where the LED light strip  200  and the printed circuit board  420  are soldered to each other. When soldering, the soldering pads “b” on the first surface  2001  of the LED light strip  200  contact the soldering pads “a” on the second surface  422  of the printed circuit board  420 , and the soldering pads “a” on the first surface  421  of the printed circuit board  420  contact the thermo-compression heating head  51 . Under the circumstances, the heat from the thermo-compression heating head  51  can directly transmit through the soldering pads “a” on the first surface  421  of the printed circuit board  420  and the soldering pads “a” on the second surface  422  of the printed circuit board  420  to the soldering pads “b” on the first surface  2001  of the LED light strip  200 . The transmission of the heat between the thermo-compression heating head  51  and the soldering pads “a” and “b” is not likely to be affected by the circuit protecting layer  200   c  which has relatively less thermal conductivity, and, consequently, the efficiency and stability regarding the connections and soldering process of the soldering pads “a” and “b” of the printed circuit board  420  and the LED light strip  200  can be improved. As shown in  FIG.  102   , the printed circuit board  420  and the LED light strip  200  are firmly connected to each other by the soldering material “g”. Components between the virtual line M and the virtual line N of  FIG.  102    from top to bottom are the soldering pads “a” on the first surface  421  of the printed circuit board  420 , the printed circuit board  420 , the power circuit layer  420   a , the soldering pads “a” on the second surface  422  of the printed circuit board  420 , the soldering pads “b” on the first surface  2001  of LED light strip  200 , the circuit layer  200   a  of the LED light strip  200 , and the circuit protecting layer  200   c  of the LED light strip  200 . The connection of the printed circuit board  420  and the LED light strip  200  are firm and stable. 
     In other embodiments, an additional circuit protecting layer can be disposed over the first surface  2001  of the circuit layer  200   a . In other words, the circuit layer  200   a  is sandwiched between two circuit protecting layers  200   c , and therefore the first surface  2001  of the circuit layer  200   a  can be protected by the circuit protecting layer  200   c . A part of the circuit layer  200   a  (the part having the soldering pads “b”) is exposed for being connected to the soldering pads “a” of the printed circuit board  420 . Under the circumstances, a part of the bottom of the LED light source  202  contacts the circuit protecting layer  200   c  on the first surface  2001  of the circuit layer  200   a , and the other part of the bottom of the LED light source  202  contacts the circuit layer  200   a.    
     In addition, according to the embodiment shown in  FIG.  100    to  FIG.  103   , the printed circuit board  420  further comprises through holes “h” passing through the soldering pads “a”. In an automatic soldering process, when the thermo-compression heating head  51  automatically presses the printed circuit board  420 , the soldering material “g” on the soldering pads “a” can be pushed into the through holes “h” by the thermo-compression heating head  51  accordingly, which fits the needs of automatic process. 
     Power supply may be otherwise referred to as a power conversion module/circuit or power module, and encompass the conventional meanings of the term “power supply” commonly understood by one of ordinary skill in the art, including a meaning of “a circuit that converts ac line voltage to dc voltage and supplies power to the LED or LED module”. They are called a “power supply” herein as they are for supplying or providing power, from external signal(s) as from AC powerline or a ballast, to the LED module. And these different terms of a “power conversion module/circuit” and a “power module” may be used herein or in future continuing applications to mean/denote the power supply. 
     As depicted above, in some embodiments, power supply  5  may include a printed circuit board and electronic components. The electronic components have at least one inductor, transistor, capacitor, resistor, or integrated circuit on the first surface of the printed circuit board. The expression of “have at least one . . . or” in the disclosure excluding its parent and child applications means at least one, or any combination thereof. For example, the electronic components may comprise one inductor. The electronic components may comprise two inductors. The electronic components may comprise one resistor. The electronic components may comprise two resistors. The electronic components may comprise one transistor. The electronic components may comprise one integrated circuit. The electronic components may comprise one integrated circuit and one resistor. Alternatively, the electronic components may comprise any combination of at least two of an inductor, a transistor, a capacitor, a resistor, and an integrated circuit. In other words, electronic components may be at least one selected from the group consisting essentially of an inductor, a transistor, a capacitor, a resistor, and an integrated circuit. 
     If any terms in this application conflict with terms used in any application(s) from which this application claims priority, or terms incorporated by reference into this application or the application(s) from which this application claims priority, a construction based on the terms as used or defined in this application should be applied. 
     The above-mentioned features of the present invention can be accomplished in any combination to improve the LED tube lamp, and the above embodiments are described by way of example only. The present invention is not herein limited, and many variations are possible without departing from the spirit of the present invention and the scope as defined in the appended claims.