Abstract:
The present invention relates to the technical field of LED packaging, in particular to an easily-assembled COB lamp bead, a support for the lamp bead, a method for manufacturing the lamp bead and an easily-assembled LED module using the lamp bead. For the LED lamp bead provided by the present invention, as a first metal welding layer is provided on the bottom surface, it is just required to directly weld the lamp bead in a heat sink during assembling. Due to a power-taking slot formed of a positive plate and a negative plate in a matched manner, it is just required to insert one end of a driving circuit board, having a conductive terminal, into the slot during assembling. Hence, the whole assembling process is very simple, and both the efficiency and quality of assembling are effectively improved.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the technical field of LED packaging, in particular to an easily-assembled COB lamp bead, a support for the lamp bead, a method for manufacturing the lamp bead and an easily-assembled LED module using the lamp bead. 
       BACKGROUND OF THE INVENTION 
       [0002]    LED packaging is an important link of the production of LED lamp beads. At present, high-power LED lamp beads are generally Surface Mount Device (SMD) packaged. Although this packaging mode is relatively mature, it is required to fix wafers on a lead frame to form a separate device and then weld a plurality of separate devices onto a substrate (PCB), resulting in the disadvantages of completed process, high cost, large heat resistance and the like. In the art, it tends to develop Chip On Board (COB). 
         [0003]    COB is to directly fix LED wafers onto a substrate (PCB) for packaging, resulting in the advantages of high productivity, low heat resistance, good optical property and the like. At present, the substrates employed by COB mainly include conductive substrates made of copper or other conductive metals and insulating substrates made of ceramics or other insulating materials. For a conductive substrate having a structure as shown in  FIG. 1(   a ), LED wafers B- 5  are directly fixed onto a copper substrate B- 1 , a lamp cup B- 2  (enclosure) is formed of PPA material on the cupper substrate and then filled with packaging glue B- 3 , a copper terminal B- 4  is provided on the lamp cup, and the LED wafers B- 5  are bonded and connected to the copper terminal B- 4  for taking power. Generally, the copper terminal B- 4  extends outside to be partially exposed, facilitating the copper terminal B- 4  to be connected to the driving circuit. For an insulating substrate having a structure as shown in  FIG. 1(   b ), a conductive layer B- 7  is plated on a ceramic substrate B- 6 , LED wafers B- 5  are fixed in a wafer fixing region on the conductive layer B- 7  and connected together by bonding wires, and a lamp cup B- 2  (enclosure) is formed around the wafer fixing region and filled with packaging glue B- 3 , wherein the conductive layer B- 7  partially extends to the outside of the lamp cup B- 2  to be exposed, facilitating the electrical connection to the driving circuit. 
         [0004]    Therefore, a conductive region for connecting a driving circuit is exposed from the surface of each of the packaged LED beads. Meanwhile, to mount the lamp bead onto a heat sink, a fixed pore is generally further formed on the substrate. As disclosed in Patent CN102853299A, when assembling such a lamp bead, it is generally required to fix a substrate onto a heat sink first by fastening screws or other fastening elements in aid of the fixed pore, and then, weld a conductive lead in the conductive region and weld the other end of the conductive lead onto the driving circuit board. Apparently, such a structure has the following disadvantages: 
         [0005]    the fixing operation is complicated as screws or other auxiliary fastening components are required, and ceramic substrates or other fragile substrates are very likely to be damaged during the fixation, causing high defect rate; and 
         [0006]    the assembling efficiency is greatly reduced as the welding of the conductive leads is complicated, and it is likely to make the whole lamp unqualified due to the substandard welding at the welding points. 
         [0007]    Therefore, the existing lamp bead structure makes the assembling process difficult, thereby causing the problems of low assembling efficiency and poor assembling quality. 
       SUMMARY OF THE INVENTION 
       [0008]    One objective of the present invention is to provide an LED lamp bead which is easy to be secured to a heat sink without any lead welding and thus to be assembled simply and which improves both the assembly efficiency and quality, in order to avoid deficiencies in the prior art. 
         [0009]    Another objective of the present invention is to provide a support for the lamp bead and an LED module using the lamp bead, in order to avoid deficiencies in the prior art. 
         [0010]    Yet another objective of the present invention is to provide a method for manufacturing the LED lamp bead with simple steps, saved cost and high productivity, in order to avoid deficiencies in the prior art. 
         [0011]    The objectives of the present invention are achieved by the following technical solutions. 
         [0012]    A support for an easily-assembled COB lamp bead is provided, including a substrate and a power-taking plate for supplying power to the substrate, wherein one surface of the substrate is plated with a first metal welding layer to form a welding surface, the power-taking plate including a positive plate and a negative plate, which are electrically conductive, the positive plate and the negative plate being insulated from and matched with each other to form a power-taking slot. 
         [0013]    Preferably, the support is obtained by punching a conductive plate. 
         [0014]    An easily-assembled COB lamp bead is provided, including a support onto which LED wafers are adhered on its front surface, wherein the bottom surface of the support is plated with a first metal welding layer, the support including a substrate and a power-taking plate for supplying power to the LED wafers, the power-taking plate including a positive plate and a negative plate, which are electrically conductive, the positive plate and the negative plate being insulated from and matched with each other to form a power-taking slot. 
         [0015]    Preferably, a lamp cup is formed on the front surface of the support, the lamp cup including a cup cavity to which the substrate is exposed to form a wafer fixing region for fixing the LED wafers; and each of the positive plate and the negative plate includes a power supply region, a fixing region and a power taking region, the power supply region being exposed to the cup cavity, the fixing region is embedded on a wide wall of the lamp cup, the power taking region being exposed outside the lamp cup and forming the power-taking slot. 
         [0016]    Preferably, a first spacer for isolating the substrate from the power-taking plate is provided in the cup cavity. 
         [0017]    Preferably, a second spacer for isolating the positive plate from the negative plate is provided in the cup cavity. 
         [0018]    Preferably, the first metal welding layer includes a nickel layer covering the bottom surface of the support and a silver layer covering the nickel layer. 
         [0019]    An easily-assembled LED module is provided, including a heat sink, a lamp bead fixed in the heat sink and a driving circuit board for supplying current to the lamp bead, wherein the lamp bead is the easily-assembled lamp bead according to any one of claims  3 - 7 ; a junction surface of the heat sink with the lamp bead is plated with a second metal welding layer, the first metal welding layer and the second metal welding layer being fixed with each other by welding; and a power supply terminal is provided at one end portion of the driving circuit board, the power supply terminal being snapped in the power-taking slot to supply power to the power-taking plate. 
         [0020]    Preferably, an inner cavity is formed in the heat sink, the driving circuit board being disposed in the inner cavity; a welding surface of the heat sink and the lamp bead is provided with a through hole; a conductive region, in which the conductive terminal is to be provided, of the driving circuit board is in interference fit with the conductive slot, the size between the two sides of the conductive region being larger than that of the power-taking slot and the length of the conductive region being equal to the depth of the power-taking slot. 
         [0021]    Finally, a method for manufacturing an easily-assembled COB lamp bead, including the following steps of: a plate making step, an injection molding step, a wafer fixing step, a glue filling step and a separation step, wherein: 
         [0022]    the plate making step: punching a conductive plate to form a support, the support including a substrate, a positive plate and a negative plate, the substrate, the positive plate and the negative plate being connected to the plate by connecting bars, respectively; 
         [0023]    the injection molding step: injection-molding a lamp cup on the plate with the support punched thereon, the lamp cup including a cup cavity, the cup cavity and the substrate forming a wafer fixing region, the cup cavity, the positive plate and the negative plate forming a power supply region; 
         [0024]    the wafer fixing step: fixing LED wafers in the wafer fixing region of the substrate, and conductively connecting the substrate to the positive plate and the negative plate, respectively; 
         [0025]    the glue filling step: filling packaging glue in the cup cavity; and 
         [0026]    the separation step: cutting off the connecting bars between the substrate, the positive plate and the negative plate, and the plate, to allow the lamp bead to separate from the plate. 
         [0027]    The present invention has the following beneficial effects that. For the LED lamp bead, as a first metal welding layer is provided on the bottom surface, it is just required to directly weld the lamp bead in a heat sink during assembling; due to a power-taking slot formed of a positive plate and a negative plate in a matched mode, it is just required to insert one end of a driving circuit board, having a conductive terminal, into the slot during assembling. Hence, the whole assembling process is very simple, and both the efficiency and quality of assembling are effectively improved. For the LED lamp bead of the present invention, as a first metal welding layer is provided on the bottom surface, and due to a power-taking slot formed of a positive plate and a negative plate in a matched mode, the LED lamp bead made of this support has the beneficial effects as mentioned above. For the LED module of the present invention, as a metal welding layer is provided on the bottom surface and the junction surface of the heat sink and the lamp bead is plated with a second metal welding layer, it is just required to directly weld the heat sink and the lamp bead together by tin paste during the assembling. Hence, the process is simple. Meanwhile, when assembling the driving circuit board of the LED module with the LED lamp bead, the power supply terminal of the LED driving board is directly snapped into the power-taking slot of the LED lamp bead, resulting in simple assembly, high efficiency and stable quality. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The present invention will be described reference to the accompanying drawings. Embodiments mentioned in the drawings do not form any limitation to the present invention. It is possible for one of ordinary skill in the art to obtain other drawings according to the following drawings without any creative efforts. 
           [0029]      FIG. 1  is a structure diagram of the background of the present invention; 
           [0030]      FIG. 2  is an exploded view of embodiment 1 of the present invention; 
           [0031]      FIG. 3  is a structure diagram of a lamp bead according to embodiment 1 of the present invention; 
           [0032]      FIG. 4  is a diagram of a conductive plate in progress according to embodiment 1 of the present invention; and 
           [0033]      FIG. 5  is a structure diagram of a driving circuit board according to embodiment 2 of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    The present invention will be further described by the following embodiments. 
       Embodiment 1 
       [0035]    An easily-assembled LED module as shown in  FIG. 3  includes a columnar heat sink  1  (it may also be a heat sink  1  of a sunflower structure or other structures). One end of the heat sink  1  is open, while the other end thereof is a lamp bead  3  setting surface  11  for allowing a lamp bead  3  arranged thereon. The lamp bead  3  arrangement surface  11  is plated with a nickel layer (not shown). An inner cavity, having a driving circuit board  2  accommodated therein, is formed in the heat sink  1 . One end of the driving circuit board  2  is provided with a power supply terminal to form a conductive region  21 . The power supply terminal includes a positive terminal  211  and a negative terminal  212 . In this embodiment, the size of the conductive region  21  of the driving circuit board  2  is smaller than that of other parts of the circuit board, so that only the conductive region  21  of the driving circuit board  2  can pass through a through hole  12  on the lamp bead  3  arrangement surface  11  of the heat sink  1 . As shown in  FIG. 4 , the lamp bead  3  on the lamp bead  3  arrangement surface  11  of the heat sink  1  includes a support, a lamp cup  34  and packaging glue  35 . The bottom surface of the support is plated with a nickel layer, while a silver layer is plated on the surface of the nickel layer. Both the nickel layer and the silver layer are metal welding layers. When it is required to fix the lamp bead  3  onto the heat sink  1 , the welding fixation between the lamp bead  3  and the heat sink  1  may be realized by tin paste or other solders. 
         [0036]    Specifically, as shown in  FIG. 3 , the support includes a substrate  31  and a power-taking plate consisting of a positive plate  32  and a negative plate  33 . The substrate  31 , the positive plate  32  and the negative plate  33  are fixedly connected to the lamp cup  34 , respectively, so that the relative positions of the substrate  31 , the positive plate  32  and the negative plate  33  are fixed, wherein the lamp cup  34  includes a cup cavity  341  to which the substrate  31  is exposed to form a wafer fixing region, a plurality LED wafers (not shown) are arranged on the wafer fixing region, and the LED wafers (or the LED wafers and the substrate  31 , or the LED wafers and the power-taking plate) are conductively connected by bonding wires. Specifically, fixing the LED onto the substrate  31  may be realized by the conventional methods in the art and will not be repeatedly described here. As shown, both the positive plate  32  and the negative plate  33  are of a U-shaped structure. A portion of each of the positive plate and the negative plate partially in the cup cavity  341  is exposed to form a power supply region  38  for supplying power to the LED wafers, respectively, and the other portion thereof is embedded in the lamp cup  34  to allow the positive plate  32  and the negative plate  33  to be fixed by the lamp cup  34 . The later portion is a fixing region of the positive plate  32  and the negative plate  33 . More importantly, both the positive plate  32  and the negative plate  33  have portions exposed outside the lamp cup  34  to form a power-taking region  37  for directly taking power from the driving circuit board  2 . The power-taking region  37  of the positive plate  32  and power-taking region  37  of the negative plate  33  are matched with each other to form a power-taking slot  36 . The power-taking slot is used for allowing the conductive region  21  of the driving circuit board  2  to inert therein. The conductive region  21  is arranged to be in interference fit with the power-taking slot  36 . When the conductive region  21  is inserted into the power-taking slot  36 , the positive terminal  211  of the driving circuit board  2  will be connected to the positive plate  32 , and the negative terminal  21  will be connected to the negative plate  33 , so that an ON loop is formed between the power-taking plate and the driving circuit board  2 . 
         [0037]    In conclusion, the LED module is very easy to assemble. The assembling may be completed, by coating tin paste or other solders onto the heat sink  1 , then welding the LED lamp bead  3  onto the heat sink  1 , and inserting the driving circuit board  2  from the opening at the lower end of the heat sink  1  to allow the conductive region  21  thereof to pass through the through hole  12  of the lamp bead  3  arrangement surface  11  of the heat sin 1 until the conductive region  21  is inserted into the power-taking hole  36 . The LED module is simple in assembling and advantageous for automation, and can effectively improve the efficiency and quality of assembling. 
         [0038]    It is to be noted that: 
         [0039]    (1) The reason why a nickel layer and a silver layer in this embodiment are plated on the rear surface of the support as metal welding layers is mainly that the silver layer and the nickel layer can provide corresponding protection for the lamp bead  3 . According to actual needs, it is also possible to plate only one of the nickel layer and the silver layer on the rear surface of the support, as long as the thickness is properly increased. Further, for those skilled in the art, either the nickel layer on the heat sink  1  or the nickel layer and the silver layer on the rear surface of the support may be replaced by other metal materials beneficial to welding, and such metal materials will not be described here. 
         [0040]    (2) The case where “the power-taking region  37  of the positive plate  32  and power-taking region  37  of the negative plate  33  are matched with each other to form a power-taking slot  36 ” described herein includes a case where the power-taking region  37  of the positive plate  32  and power-taking region  37  of the negative plate  33  are matched with each other or matched with other parts of the lamp bead  3  to form a power-taking slot  36 , for example, a case where the power-taking region  37  of the positive plate  32 , power-taking region  37  of the negative plate  33  and the outer wall of the lamp cup  34  together form a power-taking slot  36 . 
         [0041]    (3) The support in this embodiment is formed by directly punching copper material. Of course, it is also possible to form the support from other materials (as stated in the background art), for example, insulating material, as required, as long as a conductive film is plated on the surface of the support to provide for the electrical conductivity. 
         [0042]    (4) Although both the positive plate  32  and the negative plate  33  in this embodiment are of a U-shaped structure, for those skilled in the art, structures in other shapes such as an L-shape may be possible, as required, as long as the positive plate  32  and the negative plate  33  are allowed to form the power supply region  38  in the cup cavity  341 , form the power-taking region  327  outside the lamp cup  34  and form the power-taking slot  36  in a matched manner. 
         [0043]    In addition, as shown in  FIG. 3 , a first spacer  342  for isolating the substrate  31  from the power-taking plate and a second spacer  343  for isolating the positive plate  32  from the negative plate  33  are provided in the cup cavity  341  of the lamp cap  34 . The first spacer  342  and the second spacer  343  may effectively improve the safety performance between the substrate  31  and the power-taking plate, as well as between the positive plate  32  and the negative plate  33 , for example, the creep distance between the substrate  31  and the power-taking plate and the insulating performance between the positive plate  32  and the negative plate  33 . 
         [0044]    Specifically, the method for manufacturing the lamp bead  3 , including the following steps: 
         [0045]    a plate making step: as shown in  FIG. 5 , punching a conductive plate  4  to form a support, the support including a substrate  31 , a positive plate  32  and a negative plate  33 , the substrate  31 , the positive plate  32  and the negative plate  33  being connected to the plate by connecting bars  41 , respectively; 
         [0046]    a injection molding step: injection-molding a lamp cup  34  on the plate with the support punched thereon; 
         [0047]    a wafer fixing step: fixing LED wafers in the wafer fixing region of the substrate  31 , and conductively connecting the substrate  31  to the positive plate  32  and the negative plate  33 , respectively; 
         [0048]    a glue filling step: filling packaging glue  35  in the cup cavity  341  to form a lamp bead  3 ; and 
         [0049]    a separation step: cutting off the connecting bars  41  between the substrate  31 , the positive plate  32  and the negative plate  33 , and the plate, to allow the lamp bead  3  to separate from the plate. 
       Embodiment 2 
       [0050]    Another implementation of an easily-assembled LED module is provided here. The main technical solution of this embodiment is the same as embodiment 1, and the features not explained in this embodiment refer to those of embodiment 1 and will not be repeatedly described herein. This embodiment differs from embodiment 1 in that, as shown in  FIG. 5 , the length of the conductive region  21  is equal to the depth of the power-taking slot  36 , one end of the conductive region  21  being a driving circuit board  2  body having a size larger than that of the power-taking slot, while the other end thereof being connected to a fixing portion  22  having a size larger than that of the power-taking slot  36 . That is, a fixing portion  22  is further provided at the upper end of the conductive region  21 , and the fixing portion  22  may be separately connected to the conductive region  21 . When in assembling, the driving circuit board  2  is inserted in position and the fixing portion  22  is fixedly connected to the conductive region  21 , so that the driving circuit board  2 , the lamp bead  3  and the heat sink  1  are joined more firmly. Of course, the fixing portion  22  may also be integrated with the driving circuit board  2 . In this case, for assembling, the through hole  12  and the power-taking slot  36  may be differently sized in different directions, so that the fixing portion  22  is inserted along the larger size direction of the through hole  12  and the power-taking slot  36  and then rotated by a certain angle to be snapped in the smaller size direction. 
         [0051]    It should be noted that, the above embodiments are merely provided to describe the technical solutions of the present invention, instead of limiting the protection scope of the present invention. Although the present invention has been described in details by preferred embodiments, it should be understood that modifications or equivalent replacements may be made by one of ordinary skill in the art without departing from the spirit and scope of the technical solutions of the present invention.