Patent Publication Number: US-2015070881-A1

Title: Led light tube of module type

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a light emitting diode (LED) light tube, more particularly to a module type integrally formed LED light tube including a modularized LED base and a modularized wire-holding frame unit. 
     2. The Prior Arts 
     Owing to high efficiency, long lasting, small size, low energy consuming, swift in response, and mature advance in the modern electronics lately, a majority of traditional light bulbs or light tubes are gradually replaced with LED light tubes. It is in the trend of research how to apply the LEDs in the mostly and highly used fluorescent lamps. 
     A prior art LED light tube generally includes a light tube, a heat dissipation plate, a printed circuit board, a plurality of LED units and two conductive caps. The heat dissipation plate is mounted within the light tube while the printed circuit board is mounted on the heat dissipation plate. The LED units are connected electrically with the printed circuit board. 
     During the assembly, the LED units are first of all soldered on the printed circuit board, after which, the LED units and the printed circuit board are mounted on the heat dissipation plate via assembly elements. The above-mentioned elements are available in form of finished products, wherein the LED units are manufactured from wafer by high-tech companies, the dies by the medium size companies while the packing is done by small size companies. In addition, the printed circuit board is fabricated via etching, exposure process and coating process. 
     SUMMARY OF THE INVENTION 
     A prior art LED light tube includes a plurality of LED units and a printed circuit plate which are fabricated through several processes and they are assembled together so as to form the LED light tube. The preceding several processes and assembly process and several structure of the LED units and the printed circuit plate are in fact not directly related to the LED light tube so that an overall manufacturing cost thereof cannot be reduced, thereby wasting a relatively large amount of materials. 
     Regarding an LED unit, the high tech companies usually fabricated wafers, which are transported to medium size companies, where the wafer is fabricated into LED dies, each of which is again wire bond and is molded by small size companies via molded compound to produce as the LED unit. It is noted that a large amount of molded compound consisting of fluorescent glue is required to conduct the molded process. The manufacturing cost is therefore high and consequently results in long manufacturing time. 
     The main objective of the present invention is to provide a module type integrally formed LED light tube. The module type integrally formed LED light tube of the present invention accordingly includes a modularized LED base having a light emitting side formed with a recess, at least one illumination unit and at least one bridging unit being fixed on a bottom surface of the recess, the illumination unit and the bridging unit being connected electrically via wire-bond technique, wherein the illumination unit is constituted by a plurality of LED dies and the bridging unit is constituted by a plurality of conductive elements, one conductive element being disposed between an adjacent pair of the LED dies; a heat dissipation base for receiving and supporting the modularized LED base thereon and having two opposite peripheral sides respectively formed sliding grooves; a circuit unit disposed on the heat dissipation base in such a manner that the circuit is located adjacent to one side of the recess; an optical layer disposed over and covering the illumination unit and the bridging unit; a protection layer disposed over and covering the optical layer; and a diffusion shield disposed above the heat dissipation base and having two peripheral sides formed with downwardly and inwardly bent projections slidably engaging the sliding grooves of the heat dissipation base, thereby enclosing the LED dies therein such that the diffusion shield is located above and transversely to a light emitting path of the LED dies. 
     In the present invention, the recess in a modularized LED base is relatively narrow in width and since the optical layer and the protection layer only need to cover the relatively small width of the recess for shielding the LED units, the cost of material expense is greatly reduced and hence shortening the manufacture time. 
     One distinct feature of the present invention resides in that once the LED dies and the conductive elements are disposed on the bottom surface of the recess in the modularized LED base, the optical layer and the protection layer can be sequentially disposed over the LED dies, thereby finishing the production of the LED light tube of the present invention. Under such a situation, several processes of the prior are deleted, thereby shortening manufacture time and enhancing the production yield. 
     Another distinct feature of the present invention resides in that the LED dies coupled electrically via the conductive elements for various objective can shorten the distance between adjacent pair of the LED dies. Hence an appropriate adjustment can be conducted among the LED dies in order to achieve densely arrangement of the LED dies so that the LED light tubes thus produced can provide the outmost amount of brightness. At the same time, during the wire-bond operation, since the LED dies and the conducting elements can be kept at appropriate distance, since shorter wires are required for wire bond purpose, tangling among the wires can be avoided. 
     In accordance with the integrally formed and modularized concept, an LED base with the recess is modularized in such a manner that the illumination unit and the bridging unit are formed in the recess. The heat dissipation base is fabricated in such a manner to have a plurality of heat dissipation fins with increased surface to provide the outmost heat dissipation effect. In addition, a modularized wire-holding frame unit is provided according to the present invention for interconnecting electrically the circuit units and the conductive elements. 
     Therefore, owing to virtue of modularization of the LED base and the wire-holding frame unit, the LED light tubes of different longitudinal lengths can be formed for different specifications. Hence, the cost of material expense is greatly reduced and hence shortening the manufacture time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which: 
         FIG. 1  shows a perspective view of a modularized LED base employed in an integrally formed light emitting diode (LED) light tube of the present invention; 
         FIG. 2   a  is a perspective view of a heat dissipation base employed in the integrally formed LED light tube of the present invention; 
         FIG. 2   b  is a perspective view of another heat dissipation base employed in the integrally formed LED light tube of the present invention; 
         FIG. 2   c  is a perspective view of yet another heat dissipation base employed in the integrally formed LED light tube of the present invention; 
         FIG. 3   a  illustrates a conductive element employed in the integrally formed LED light tube of the present invention; 
         FIG. 3   b  illustrates another conductive element employed in the integrally formed LED light tube of the present invention; 
         FIG. 4  is a perspective of the first embodiment of the integrally formed LED light tube of the present invention; 
         FIG. 5  is an exploded view of  FIG. 4 ; 
         FIG. 6  is a perspective of the second embodiment of the integrally formed LED light tube of the present invention; 
         FIG. 7  shows a cross-section view of the third embodiment of the integrally formed LED light tube of the present invention; and 
         FIG. 8  shows a cross-section view of the fourth embodiment of the integrally formed LED light tube of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a perspective view of a modularized LED base employed in an integrally formed light emitting diode (LED) light tube of the present invention. As shown in  FIG. 1 , the LED light tube  10  of module type according to the present invention includes a modularized LED base  1  having a light emitting side ES formed with a recess  11 , at least one illumination unit and at least one bridging unit being fixed on a bottom surface of the recess  11 . Preferably, the recess  11  has two lateral side walls extending inclinedly from two opposite sides of the bottom surface within a range of 40°˜65°. 
     In this embodiment, the illumination unit and the bridging unit are connected electrically via wire-bond technique, wherein the illumination unit is constituted by a plurality of LED dies  31  and the bridging unit is constituted by a plurality of conductive elements  33 , one conductive element  33  is disposed between an adjacent pair of the LED dies  31  or one LED die  31  is disposed between an adjacent pair of the conductive elements  33 . Note that a gold wire is applied for the wire-bond. 
     Note that arrangement among the LED dies  31  and the conductive elements  33  depends on the actual application, for instance, the arrangement can be one regular basis: one LED die  31  followed by one conductive element  33  and followed by one LED die  31 . Alternatively, the arrangement can be one LED die  31  followed by two or three successive conductive element  33  or a series of LED dies  31  followed by a series of conductive elements  33 . However, the arrangement of the above-mentioned elements should not be limited only thereto. 
       FIG. 2   a  is a perspective view of a heat dissipation base employed in the integrally formed LED light tube of the present invention. The LED light tube of the present invention further includes a heat dissipation base  2  for receiving and supporting the modularized LED base  1  thereon. The heat dissipation base  2  is preferably made from aluminum via extrusion method, has an interior portion that is semi-circle shape in cross-section and that defines a reception chamber  21  therein. A driver is disposed within the reception chamber  21  in the heat dissipation base  1  for driving the illumination unit. 
     The heat dissipation base  2  has two opposite peripheral sides respectively formed with a first pair of sliding grooves  23  and a second pair circular sliding grooves  25 , their purpose will be explained in the following paragraphs. 
     The heat dissipation base  2  further has an upper portion that defines two sliding channels  27  at two peripheral portions thereof, and an intermediate channel  271  between the sliding channels  27 . Preferably, the modularized LED base  1  has a positioning seat  1   a  fixed in the intermediate channel  271  in the heat dissipation base  1  (see  FIG. 2   a ) such that the positioning seat  1   a  is located between the sliding channel  27 . 
     Referring again to  FIG. 2   a , two circuit units  5  are disposed respectively within the sliding channels  27  in the heat dissipation base  1  such that the circuit units  5  are located adjacent to two sides of the recess  11 . In this embodiment, the circuit units  5  are electrically connected to two of the conductive elements  3  via an external wire  41 . 
     In the event, only a single circuit unit  5  is implemented, the positive and negative ends  51 ,  53  of the circuit unit  5  are connected electrically to a power line  55 , which is latter coupled electrically the driver in the reception chamber  21 . In this embodiment, a printed circuit board (PCB), a ceramic printed circuit board or other printed circuit serves as the conductive circuit  5 . 
     Preferably, the positive and negative ends of the above circuit unit  5  are connected electrically to two of the conductive elements  33  via the external wire  41 . 
     In the event, two circuit units  5  are implemented, one circuit unit  5  serves as the positive end while the other circuit unit  5  serves as the negative end connected respectively to the power line  55 . 
       FIG. 2   b  is a perspective view of another heat dissipation base employed in the integrally formed LED light tube of the present invention. As best shown in  FIG. 2   b , the heat dissipation base  2  has a lower portion that surrounds the interior portion, and a plurality of heat dissipation fins  28  projecting outwardly and radially from the lower portion. Each of the heat dissipation fins  28  has external surface in wave configuration. 
       FIG. 2   c  is a perspective view of yet another heat dissipation base employed in the integrally formed LED light tube of the present invention. As best shown in  FIG. 2   c , the heat dissipation base  2  has a lower portion that is located below the interior portion and that is formed with a plurality of heat dissipation fins  28  projecting downwardly in a parallel manner. Each of the heat dissipation fins  28  has a truncated cone-shaped upper portion and a lower portion with external surface in a waveform configuration, the total structure thereof increases an overall surface area to enhance the heat dissipation effect of the LED light tube of the present invention. 
     An important factor to note in the above embodiment is that the middle heat dissipation fin  28  has the greatest surface area while the surface area of the heat dissipation fin decreases gradually outward with respect to the middle ones. By virtue of such configuration, undesired heat from the modularized LED base can be dissipated effectively to an exterior of the LED light tube of the present invention. 
     Another important factor to note is that the arrangement, configuration and size of the heat dissipation fins are to be designed in accordance with the actual need, and therefore should not be limited only to those described above. 
       FIG. 3   a  illustrates a conductive element employed in the integrally formed LED light tube of the present invention and  FIG. 3   b  illustrates another conductive element employed in the integrally formed LED light tube of the present invention. As best shown in  FIG. 3   a , each of the conductive elements  33  has a top surface formed with a conductive circuit  331  and two joining pads  333  at two opposite ends of the conductive circuit  331  to facilitate wire bonding or soldering purposes during the fabrication or manufacturing process. 
     Alternatively, each of the conductive elements  33  further includes at least one soldering ball  335  disposed on one joining pad  333  of a respective one of the conductive elements  33  to facilitate wire bonding or soldering purposes during the manufacturing process, as best shown in  FIG. 3   b . The soldering ball  335  is suitable for high temperature soldering purpose. 
     In this embodiment, each of the conductive elements  33  is a multi layer structure having a lower layer made from a silicone wafer, a ceramic chip, glass chip, or non-moisture materials. The lower layer is preferably constituted by from bottom to top a titanium layer and an aluminum layer, each is formed through bumping process. 
       FIG. 4  is a perspective of the first embodiment of the integrally formed LED light tube of the present invention and  FIG. 5  is an exploded view of  FIG. 4 , wherein, the positioning seat  1   a  of the modularized LED base  1  has two opposite ends respectively located adjacent to two opposite ends of the recess, at least one of the opposite ends of the positioning seat  1   a  is formed with first and second retention holes  11   a,    13   a.  In one embodiment of the present invention, the first and second retention holes  11   a,    13   a  can be formed through the heat dissipation base  2 . 
     The first LED light tube of the present invention further includes a modularized wire-holding frame unit  43  interconnecting electrically two of the circuit units  5  and two of the conductive elements  33 . The modularized wire-holding frame unit  43  is constituted by a wire-holding frame  431  and an encapsulated block  433  encapsulating partially the wire-holding frame  431  in such a manner that two conductive plates  4331  of the wire-holding frame  431  project outwardly from the encapsulated block  433  for electrically connected to the conductive elements  33 . 
     In this embodiment, the encapsulated block  433  has two positioning legs  4311  extending into and engaging the first and second retention holes  11   a,    13   a  in the positioning seat  1   a  to prevent untimely removal of the modularized wire-holding frame unit  43  from the modularized LED base  1 . The encapsulated block  433  further has an upper groove  4313  in alignment with and in spatial communication with the recess  11  in the modularized LED base  1 , and an access opening  43131  formed below the upper groove  4313  to permit extension through of the external wire  41 . Note that the modularized wire-holding frame unit  43  is electrically isolated with the modularized LED base  1  in order to prevent occurrence of short-circuit therebetween. 
       FIG. 6  is a perspective of the second embodiment of the integrally formed LED light tube of the present invention. The second embodiment is similar to the first embodiment in structure, except that a plurality of modularized LED bases  1  are mounted on the heat dissipation base  2 . 
       FIG. 7  shows a cross-section view of the third embodiment of the integrally formed LED light tube of the present invention. The third embodiment is similar to the first embodiment in structure, except that the third embodiment further includes a diffusion shield  6  of semi-circular cross-section, disposed above the heat dissipation base  2 , and has two peripheral sides formed with downwardly and inwardly bent projections  61  slidably engaging the sliding grooves  23  of the heat dissipation base  2 , thereby enclosing the LED dies  31  therein such that the diffusion shield  6  is located above and transversely to a light emitting path of the LED dies  31 . Under this condition, the LED light tube of the present invention can provide the outmost amount of brightness and relatively large angle of light. 
       FIG. 8  shows a cross-section view of the fourth embodiment of the integrally formed LED light tube of the present invention. The fourth embodiment is similar to the first embodiment in structure; except that the fourth embodiment further includes an optical layer  100  disposed on the recess  11  of the heat dissipation base  2  in such a manner to cover the LED dies  31  and the conductive elements  33 . In this embodiment, the optical layer  100  provides the optical effects relative to the LED dies  31 , such as color mixing for the light emitted from the LED dies  31 . The optical layer  100  is preferably made from fluorescent glue or material mixture consisting of fluorescent glue and silicon resin. The fourth embodiment further includes a protection layer  200  disposed above and covering the optical layer  100  so as to isolate the vapor and dust from getting interior of the optical layer  100 . Preferably, the protection layer  200  is mainly made from silicon resin. 
     Referring to  FIGS. 4 and 8  again, the optical layer  100  and the protection layer  200  cover the recess  11  in the modularized LED base  1  and the upper groove  4313  in the encapsulated block  433  so as to prevent the vapor and dust from getting interior of the optical layer  100 , thereby preventing damage of the optical effects provided by the layer  100 . From  FIG. 4 , note that the recess  11  and the upper groove  4313  are relatively narrow in width and since the optical layer and the protection layer only need to cover the relatively small width of the recess  11  and the upper groove  4313  for shielding the LED dies  31 , the cost of material expense is greatly reduced and hence shortening the manufacture time. 
     One distinct feature of the present invention resides in that once the LED dies and the conductive elements are disposed on the bottom surface of the recess in the modularized LED, the optical layer and the protection layer can be sequentially disposed over the LED dies, thereby finishing the production of the LED light tube of the present invention. Under such a situation, several fabrication steps of the prior are deleted, thereby shortening the fabrication time and process, which in turn provides high product yield of the LED light tube of the present invention. 
     Another distinct feature of the present invention resides in that the LED dies coupled electrically via the conductive elements for various objective can shorten the distance between adjacent pair of the LED dies. Hence an appropriate adjustment can be conducted among the LED dies in order to achieve densely arrangement of the LED dies so that the LED light tubes thus produced can provide the outmost amount of brightness. At the same time, during the wire-bond operation, since the LED dies and the conducting elements can be kept at appropriate distance, since shorter wires are required for wire bond purpose, tangling among the wires can be avoided. 
     In accordance with the integrally formed concept, the modularized LED base with the recess, the illumination unit and the bridging unit are integrally fabricated, which is latter disposed on the heat dissipation base is fabricated in such a manner to have a plurality of heat dissipation fins of different lengths so as to dissipate heat therefrom. Hence, the LED light tube of the present invention survives a longer service life and provides high efficient brightness. 
     In addition, owing to modularization of the LED base and the wire-holding frame unit, and since they can be ready made in advance, the LED light tube of different specifications can be quickly produced. The cost of material expense is greatly reduced and hence shortening the manufacture time. 
     While the invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangement included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.