Abstract:
Disclosed is an integrated LED bulb that utilizes LEDs and can be used as a standard replacement bulb for incandescent lights that operate on standard household current. One or more LEDs are disposed in a lens  102  that is capable of high optical transmission efficiencies. A base portion encapsulates a printed circuit board and connectors, as well as the LED pin leads to hold the package in a secure mounting. The lens can be molded directly to the base or can be removable. The base can be formed to fit standard threaded sockets or bayonet sockets.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. patent application Ser. No. 11/189,066 entitled “C7, C9 LED Bulb and Embedded PCB Circuit Board,” by Jing Jing Yu, filed Jul. 26, 2005, and is based upon U.S. Provisional Patent Application Ser. No. 60/949,804, entitled “Watertight LED Lamp,” by Jing Jing Yu, filed Jul. 13, 2007. The entire contents of the above mentioned applications are hereby specifically incorporated herein by reference for all they disclose and teach. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Lighting is an important part of everyday life. Since the time that light bulbs were invented in 1879, light bulbs have had a significant effect on human activity by providing illumination in areas and at times that would not otherwise allow such activities. One of the goals of developing lighting technologies is to meet desired illumination requirements for various activities in various venues, such as homes, offices, restaurants, etc., and for various purposes, including utility and decorative purposes.  
         [0003]     Light emitting diodes (LEDs) are semiconductor diodes that belong to the group of electroluminescent luminaries. Photons are emitted from LEDs by recombining charge-carrier pairs in a semiconductor with an appropriate energy band gap. As a result, LEDs provide narrow bands of radiation. LEDs constitute desirable sources of lighting because they operate at low voltage and power, are small and have an extended lifetime and stability.  
       SUMMARY OF THE INVENTION  
       [0004]     An embodiment of the present invention may comprise: an integrated LED bulb that replaces C-type incandescent bulbs comprising: a lens; a printed circuit board comprising: conductor leads that are connected to electrical conductors that connect to an alternating current electrical source; a full wave rectifier that rectifies the alternating current electrical source to generate a full wave rectified output signal; an integrating capacitor that integrates the full wave rectified output signal to generate an integrated direct current signal; a zener diode that controls the voltage level of the integrated direct current signal to produce a substantially constant output voltage; at least one light emitting diode disposed in the lens that is connected in parallel with the zener diode, and that generates a substantially constant optical output in response to the substantially constant output voltage produced by the zener diode, the light emitting diode having pin leads that are soldered directly to the printed circuit board; a base that is over-molded around the printed circuit board, the conductors, and the leads that are connected to the electrical conductors and the pin leads that are soldered to the printed circuit boards to form a secure, stable base that protects the printed circuit board, and which has a standard format for C-type bulbs, so that the base fits into standard C-type bulb sockets that are attached to the alternating current electrical source.  
         [0005]     Another embodiment of the present invention may comprise: a method of making an LED bulb that replaces C-type incandescent bulbs comprising: providing a lens; providing at least one LED; connecting the at least one LED in parallel with a zener diode disposed on a printed circuit board using LED pin leads that are soldered to connectors on the printed circuit board; connecting the zener diode in parallel with an integrating capacitor disposed on the printed circuit board so that a substantially constant output voltage is produced that is applied to the at least one LED to provide a substantially constant optical output; connecting the integrating capacitor in parallel with a full wave rectifier disposed on the printed circuit board so that a source of alternating current applied to the full wave rectifier is integrated by the integrating capacitor; connecting electrical conductors to the full wave rectifier; and molding a base around the printed circuit board, the LED pin leads, the conductors and the conductor leads to form a secure, stable base that has a standard format for C-type bulbs, so that the base fits into standard C-type bulb sockets that are attached to the source of alternating current. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a schematic illustration of an integrated LED bulb.  
         [0007]      FIG. 2  is a circuit diagram of an embodiment of a printed circuit board that is used with an integrated LED bulb.  
         [0008]      FIG. 3  is a circuit diagram of another embodiment of a printed circuit board that is used with an integrated LED bulb.  
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0009]      FIG. 1  discloses an integrated LED bulb  100 . As shown in  FIG. 1 , the LED bulb  100  may be a C7 type bulb, or a C9 type bulb, such as those used as screw-in Christmas tree light bulbs. The C7 type and C9 type bulbs can also have bayonet type connectors, although the screw-in type is a more common type of connector. The integrated LED bulb  100  includes a lens  102  that is connected to a base  112 . Connection of the lens  102  to the base  112  can be effectuated in the manner disclosed in U.S. Provisional Patent Application 60/949,804, filed Jul. 13, 2007, entitled “Water Tight LED Lamp,” which is specifically incorporated herein by reference for all that it discloses and teaches. In other words, the lens  102  may have a neck portion that is inserted into a socket in the base  112 . Alternatively, base  112  and lens  102  may be attached by using thermal bonding, sonic bonding, or solvent bonding, a friction interference fit, use of an adhesive or threaded screws that allow the lens  102  to be screwed into the base  112 . Further, the neck of the lens  102  may be over-molded by the base material  112  during fabrication. LED lens  102  functions as a housing for the LED  104  and is void of any materials except for air. Since, the volume inside the lens  102  contains air, the LED  104  can transmit light rays without significant attenuation. The LED lens  102  is made of a transparent material that is capable of transmitting the light generated by the LED  104  with minimal attenuation. The lens  102  can have various optical properties, including dispersion properties, diffraction properties, frosting, coloring, transport, or other options. The lens  102  can be made of a hard clear plastic material, such as calcium carbonate, glass or any other suitable material.  
         [0010]     Typical C7 and C9 type bulbs use tungsten filaments that generate light in an evacuated bulb. Most of the electrical power is dissipated as heat in these types of bulbs. Alternatively, C7 and C9 type of bulbs have been implemented with LEDs that are encapsulated in a solid optical transmission medium, such as a plastic material. The use of the optical medium results in significant optical loss. Further, the C7 and C9 type of LED bulbs only operate on DC current and cannot be used with AC current, such as standard 110 volt AC house current.  
         [0011]     The embodiment illustrated in  FIG. 1 , incorporates a printed circuit board  106  in the base  112  that converts standard household  117  volt rms alternating current into a DC signal that is applied to the LED  104 . In this manner, the LED bulb  100  can be used with standard household current in standard screw-in or bayonet type sockets. The printed circuit board  106  can be over-molded directly into the base  112 . In that regard, the LED pins  110  that are connected to the printed circuit board, can also be over-molded into the base  112 , as illustrated in  FIG. 1 . The over-molding of the printed circuit board  106  and the LED pins  110 , as shown in  FIG. 1 , provide for a stable and secure mounting of these items in the base  112 . Similarly, brass connectors  108  are connected to voltage input port  114  and voltage input port  116 . Voltage input port  114  and voltage input port  116  are electrically connected to the printed circuit board  106 . Brass connectors  108  and voltage input ports  114 ,  116  are similarly molded directly into the base  112  and, as such, are securely held to the base  112 . In other words, all of the components are mounted directly in the base, which can be inserted directly into the socket. This substantially minimizes the size of the integrated LED bulb and allows the integrated LED bulb to exactly match the formats of various C-type of bulbs, even when the smaller candelabra type of threaded screw base is used.  
         [0012]     Although  FIG. 1  illustrates a single LED  104 , multiple LEDs can be included in the integrated LED bulb  100 . Each of the LEDs  104  can be separately soldered to the printed circuit board  106 . The LED lens  102  provides sufficient space for the inclusion of multiple LEDs in the LED bulb  100 . Multiple LEDs increase the luminescent output of the LED bulb  100 . Lens  102  is made sufficiently large to accommodate multiple LEDs  104   
         [0013]      FIG. 2  is a circuit diagram  200  illustrating the circuit of the printed circuit board  106  and items connected to the printed circuit board  106 . As shown in  FIG. 2 , the AC input port  202  has connectors  204 ,  206  that connect to the circuit illustrated in  FIG. 2 . The AC input port constitutes the brass connectors  108  illustrated in  FIG. 1  that connect to a standard household  110  volt AC power source. Fuse  208  protects the circuit  200  from excessive electric current, which protects the LEDs  222  and additional LEDs  224 , as well as the circuit  200  from burnout. Fuse  208  can be separately mounted in base  112  and can be replaceable, if desired, using a standard replaceable fuse housing. The parallel connected capacitor  210  and resistor  212  help to smooth the AC signal at the AC input port  202 . Resistor  214  lowers the voltage that is applied to the AC to DC converter/bridge  216 . The output of the AC to DC converter/bridge  216  can either be a full wave rectified signal or may be a DC signal. Capacitor  218  is sized as a larger capacitor that is capable of being charged to the peak voltage of the full wave rectified signal at the output of an AC to DC bridge, such as the full wave rectifier bridge illustrated in  FIG. 3 . Zener diode  220  establishes and maintains a zener voltage across the input of LED  222 . The zener diode not only controls the DC voltage across the integrating capacitor  218 , but also maintains a steady, constant voltage across the LED  222  and additional LEDs  224 , so that no flickering occurs in the light. In other words, a constant optical output is provided by the constant voltage across the zener diode  220 . As also shown in  FIG. 2 , additional LEDs  224  can be added in parallel to LED  222 . The LED  222  and the additional LEDs  224  can be soldered directly to the printed circuit board  106 . The AC to DC converter/bridge  216 , as indicated above, can either be a bridge such as a full wave rectifier bridge illustrated in  FIG. 3 , a half wave rectifier bridge, or other type of bridge circuit, or an AC to DC converter.  
         [0014]     Various types of AC to DC converters can be used for converter  216 . For example, a simple single chip voltage regulator can be used as the AC to DC converter  216 . Alternatively, circuits, such as those illustrated in U.S. Patent Application Publication No. US2005/0057187, published Mar. 17, 2005, entitled “Universal Light Emitting Illumination Device and Method,” as shown in  FIG. 11 , and disclosed in paragraphs 40 through 44, can be used. The advantage to all of these circuits is that they can be placed on a very small printed circuit board that can be over-molded into the base of the integrated bulb, which is inserted into a standard socket. In this manner, the circuit components are protected in the base and encapsulated in a plastic housing to prevent damage. These items are not open in the lens where they can become loose or damaged, but rather are encapsulated within the base having a standard format for connection to a standard socket.  
         [0015]      FIG. 3  is a circuit diagram  300  of an embodiment using a full wave rectifier bridge  302 . As shown in  FIG. 3 , the full wave rectifier bridge  302  generates a full wave rectified signal at its output  304  as a result of the AC signal that is applied to the input  306 . Capacitor  308  stores the peak voltage on the full wave rectified signal at the output  304 . This voltage is stabilized using the zener diode  310 .  
         [0016]     The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.