Abstract:
The present invention relates to an alternating current driven light emitting diode module. The alternating current driven light emitting diode module includes an alternating current driven light emitting diode chip, a first thermal conduction plate, and a ceramic substrate. The first thermal conduction plate is arranged on the ceramic substrate. The alternating current driven light emitting diode chip is arranged on the first thermal conduction plate. The alternating current driven light emitting diode module has better heat dissipating property and better insulation property.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a light emitting diode module, and more particularly to a light emitting diode module driven by alternating current. 
       BACKGROUND OF THE INVENTION 
       [0002]    Light Emitting Diode (LED) is a solid semiconductor light emitting device. The LED produces photons and thus emits light by electron-hole pair recombination. The LED has advantages of high luminous efficiency, small size, long life, and low pollution, and has broad application prospects in illumination devices, back light modules, and display devices, etc. 
         [0003]    The LEDs can be divided into direct current (DC) driven LEDs and alternating current (AC) driven LEDs with respect to different drive modes of the LED chips. 
         [0004]    Because the DC driven LEDs is necessary to be driven by direct current, an external circuit such as an inverter is provided and used to transform alternating current in daily power environment into direct current. However, the external circuit increases manufacturing cost, and takes up space, thus resulting in difficulty in minimizing size of the DC driven LEDs. In addition, heat generated by the external circuit increases the burden for heat dissipation function of the LEDs, thus shortening lifespan of the DC driven LEDs. 
         [0005]    Generally, AC driven LED modules refers to LEDs which can be used by directly connecting to an alternating current voltage. The AC driven LED modules can be directly used without provision of the external circuit such as the inverter, and the AC driven LED modules can be operated by applying low current. Compared to the DC driven LEDs, the AC driven LED modules have advantages of small size, cost efficiency, and long life. In recent years, application and research of the AC driven LED modules are brought into spotlight. 
         [0006]    However, heat dissipating efficiency of the AC driven LED modules is ordinary. When the AC driven LEDs generate relatively more heat, the heat is difficult to be dissipated timely and quickly, thus lifespan and reliability of the AC driven LED modules are negatively affected. 
       SUMMARY OF THE INVENTION 
       [0007]    Considering shortcomings of the conventional AC driven LED modules, the inventor of the present invention is actively doing research and making innovation, and is expecting to design an AC driven LED module with novel structure, based on many years of experience and expertise in designing and manufacturing similar products, and with the use of academic theory. The AC driven LED module in the present invention is carried out by improving the conventional AC driven LED module to have practical applicability. Through continuous research, design, and repeatedly test and improvement, the present AC driven LED module with practical value is finally carried out. 
         [0008]    One object of the present invention is to overcome the conventional shortcomings of the conventional AC driven LED modules and provide an AC driven LED module with novel structure. The AC driven LED module in the present invention has better heat dissipating efficiency and insulation property than before. 
         [0009]    The object of the present invention is achieved by the following technical solution, in which an AC driven LED module is provided. The AC driven LED module includes an AC driven LED chip, a first thermal conduction plate, and a ceramic substrate. The LED chip is driven by alternating current. The first thermal conduction plate is arranged on the ceramic substrate. The AC driven LED chip is arranged on the first thermal conduction plate. 
         [0010]    The object of the present invention is further achieved by the following technical solutions. 
         [0011]    The AC driven LED module as described above, wherein material of the ceramic substrate is aluminum oxide or aluminum nitride. 
         [0012]    The AC driven LED module as described above, wherein the AC driven LED module further includes a thermal conduction bar. An end of the thermal conduction bar is connected to the first thermal conduction plate. An opposite other end of the thermal conduction bar extends into the ceramic substrate. Material of the first thermal conduction plate and the thermal conduction bar is metal, such as aluminum or copper. 
         [0013]    The AC driven LED module as described above, wherein the first thermal conduction plate and the thermal conduction bar are integrally manufactured and connected to each other, or are fixedly attached to each other via welding or screwing. 
         [0014]    The AC driven LED module as described above, wherein the ceramic substrate includes a bottom surface, a top surface opposite to the bottom surface, and a connection hole defined in the top surface and extending into the ceramic substrate. The first thermal conduction plate is arranged on the top surface. The thermal conduction bar extends into the ceramic substrate by cooperating with the connection hole. 
         [0015]    The AC driven LED module as described above, wherein a thermal adhesive is provided and filled between the thermal conduction bar and a sidewall of the connection hole. 
         [0016]    The AC driven LED module as described above, wherein the ceramic substrate includes a bottom surface, a top surface opposite to the bottom surface, and a connection hole defined in the top surface and extending through the bottom surface. The first thermal conduction plate is arranged on the top surface. The connection hole is a step hole. A portion of the hole with wider diameter is located adjacent to bottom surface. The thermal conduction bar is moved toward the bottom surface and inserted into the connection hole, and is further connected to the first thermal conduction plate after inserted into the connection hole. 
         [0017]    The AC driven LED module as described above, wherein a thermal adhesive is provided and filled between the thermal conduction bar and a sidewall of the connection hole. 
         [0018]    The AC driven LED module as described above, wherein the AC driven LED module further includes a thermal conduction bar. An end of the thermal conduction bar is connected to the first thermal conduction plate. The ceramic substrate is formed on the first thermal conduction plate and covers an opposite other end of the thermal conduction bar by injection molding. 
         [0019]    The AC driven LED module as described above, wherein the end of the thermal conduction bar covered by the ceramic substrate includes a thermal diffusion portion. 
         [0020]    The AC driven LED module as described above, wherein the thermal diffusion portion covered by the ceramic substrate is bent. 
         [0021]    The AC driven LED module as described above, wherein the AC driven LED module further includes a second thermal conduction plate. The ceramic substrate includes a top surface, a bottom surface opposite to the top surface, and a peripheral surface located between and adjoining the top surface and the bottom surface. The first thermal conduction plate is arranged on the top surface. The second thermal conduction plate is arranged adjacent to the bottom surface or the peripheral surface. The thermal conduction bar is connected to the first thermal conduction plate and the second thermal conduction plate. Material of the first thermal conduction plate, the thermal conduction bar, and the second thermal conduction plate is metal, such as aluminum or copper. 
         [0022]    The AC driven LED module as described above, wherein the first thermal conduction plate, the second thermal conduction plate, and the thermal conduction bar are integrally manufactured and connected to one another, or are fixedly attached to each other via welding or screwing. 
         [0023]    The present invention has apparent advantages and beneficial effects compared to the conventional technologies. Based on the technical solution described above, the AC driven LED module of the present invention at least has the advantages and beneficial effects as follows: 
         [0024]    The AC driven LED module as described above, as the ceramic substrate has better heat dissipating property, thus heat, which is generated by the AC driven LED chip and transferred to the ceramic substrate through the first thermal conduction plate, can be quickly dissipated to ambient environment by the ceramic substrate. In addition, as the AC driven LED module further includes a thermal conduction bar, and the thermal conduction bar has better thermal conductive property, shortage of insufficient thermal conductive property of the ceramic substrate can be compensated by the thermal conduction bar. Speed of the heat, which is generated by the AC driven LED chip, transferring from the AC driven LED chip to the ceramic substrate is accelerated, thus heat dissipating efficiency of the AC driven LED is further increased. 
         [0025]    The above mentioned object and other objects, features, and advantages of the present invention can be better understood with reference to the following embodiments and drawings. 
         [0026]    In summary, the present invention relates to an AC driven LED module. The AC driven LED module includes an AC driven LED chip, a first thermal conduction plate, and a ceramic substrate. The first thermal conduction plate is arranged on the ceramic substrate. The AC driven LED chip is arranged on the first thermal conduction plate. The AC driven LED module has advantages of better heat dissipating property and better insulation property. The present invention has many advantages and many practical values described above, either structure or function of the product is improved a lot. In addition, the present invention makes significant technical progress, and produces useful and practical results. Furthermore, the present invention has outstanding technical effect compared to the conventional AC driven LED module, and is more suitable for practical use. The present invention truly is a novel, unobvious, and practical design. 
         [0027]    It is understood that the exemplary embodiments described above is summary of technical solution of the present invention. For clearly understanding the technical solution of the present invention, thus facilitating application of the present invention according to the specification, and also for clearly understanding the above mentioned object and other objects, features, and advantages of the present invention, embodiments and drawings are provided, as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
           [0029]      FIG. 1  is schematic cross section of an AC driven LED module in accordance with a first embodiment of the present invention. 
           [0030]      FIG. 2  is schematic cross section of an AC driven LED module in accordance with a second embodiment of the present invention. 
           [0031]      FIG. 3  is schematic cross section of an AC driven LED module in accordance with a third embodiment of the present invention. 
           [0032]      FIG. 4  is schematic cross section of an AC driven LED module in accordance with a fourth embodiment of the present invention. 
           [0033]      FIG. 5  is schematic cross section of an AC driven LED module in accordance with a fifth embodiment of the present invention. 
           [0034]      FIG. 6  is schematic cross section of an AC driven LED module in accordance with a sixth embodiment of the present invention. 
           [0035]      FIG. 7  is schematic cross section of an AC driven LED module in accordance with a seventh embodiment of the present invention. 
           [0036]      FIG. 8  is schematic cross section of an AC driven LED module in accordance with an eighth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0037]    For clearly illustration of technical solution and beneficial effect for achieving the object of the present invention, embodiments, structures, features, and beneficial effects of the present invention are described, as follows. 
         [0038]      FIG. 1  is schematic cross section of an AC driven LED module in accordance with a first embodiment of the present invention. An AC driven LED module  10  in accordance with the first embodiment includes an AC driven LED chip  12 , a first thermal conduction plate  14 , and a ceramic substrate  16 . The first thermal conduction plate  14  is arranged on the ceramic substrate  16 . The LED chip  12  is arranged on the first thermal conduction plate  14 . The first thermal conduction plate  14  is made of material with better thermal conductive property, such as metallic material. The ceramic substrate  16  is made of ceramic material with better heat dissipating property, such as aluminum oxide, aluminum nitride, or silicon carbide. 
         [0039]    In this embodiment, the AC driven LED module  10  further includes a thermal conduction bar  18 . The thermal conduction bar  18  and the first thermal conduction plate  14  are integrally manufactured and connected to each other. Similar to the first thermal conduction plate  14 , the thermal conduction bar  18  is made of material with better thermal conductive property, for example metal, such as aluminum or copper. In this embodiment, the thermal conduction bar  18  is made of aluminum, thus the thermal conduction bar  18  is cost efficient. It is noted that material of the thermal conduction bar  18  and material of the first thermal conduction plate  14  can be same as each other, or different from each other. Preferably, material of the thermal conduction bar  18  is same as material of the first thermal conduction plate  14 , thus the thermal conduction bar  18  and the first thermal conduction plate  14  can be easily integrally manufactured and connected to each other. The ceramic substrate  16  includes a bottom surface  164 , a top surface  166  opposite to the bottom surface  164 , and a connection hole  162 . The first thermal conduction plate  14  is arranged on the top surface  166 . The connection hole  162  is defined in the top surface  166 , and extends into the ceramic substrate  16  but does not extend through the bottom surface  164 . An end of the thermal conduction bar  18  distant from the first thermal conduction plate  14  is shaped to cooperate with the connection hole  162 . That is, the thermal conduction bar  18  extends inside the ceramic substrate  16  by cooperating with the connection hole  162 . 
         [0040]    In use, as the ceramic substrate  16  has better heat dissipating property, thus heat, which is generated by the AC driven LED chip  12  and transferred to the ceramic substrate  16  through the first thermal conduction plate  14 , can be quickly dissipated. The ceramic substrate  16  may has porous structure, for example. When the ceramic substrate  16  is exposed in the air, the air can be introduced into an interior of the ceramic substrate  16  through holes of the ceramic substrate  16 , thus creating thermal convection inside the ceramic substrate  16 . The air can be exhausted out of the ceramic substrate  16  by thermal convection to dissipate heat inside the ceramic substrate  16 . In this manner, heat generated by the AC driven LED chip  12  can be quickly transferred to the ceramic substrate  16 , and further dissipated to an exterior of the AC driven LED module  10  by thermal convection. Thus, heat dissipating efficiency of the AC driven LED module  10  is increased, lifespan of the AC driven LED module  10  is elongated, and reliability of the AC driven LED module  10  is enhanced. In addition, the AC driven LED module  10  might further include the thermal conduction bar  18  as in the embodiment. The thermal conduction bar  18  has better thermal conductive property, and is used to increase a surface area of the ceramic substrate  16  for transferring heat generated by the AC driven LED  12 . Thus, speed of the heat transferred to the ceramic substrate  16  is accelerated, heat dissipating efficiency of the AC driven LED module  10  is further increased. 
         [0041]      FIG. 2  is schematic cross section of an AC driven LED module in accordance with a second embodiment of the present invention. The AC driven LED module  20  of the second embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  22 , a first thermal conduction plate  24 , a ceramic substrate  26 , and a thermal conduction bar  28 . The AC driven LED module  20  differs from the AC driven LED module  10  in that the thermal conduction bar  28  and the first thermal conduction plate  24  are fixedly attached to each other via welding. 
         [0042]      FIG. 3  is schematic cross section of an AC driven LED module in accordance with a third embodiment of the present invention. The AC driven LED module  30  of the third embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  32 , a first thermal conduction plate  34 , a ceramic substrate  36 , and a thermal conduction bar  38 . The AC driven LED module  30  differs from the AC driven LED module  10  in that the thermal conduction bar  38  and the first thermal conduction plate  34  are fixedly attached to each other via a screw  35 . 
         [0043]      FIG. 4  is schematic cross section of an AC driven LED module in accordance with a fourth embodiment of the present invention. The AC driven LED module  40  of the fourth embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  42 , a first thermal conduction plate  44 , a ceramic substrate  46 , and a thermal conduction bar  48 . The AC driven LED module  40  differs from the AC driven LED module  10  in that a thermal adhesive  49  is provided and filled between the thermal conduction bar  48  and a sidewall of the connection hole  462 . As the thermal conduction bar  48  and the sidewall of the connection hole  462  is filled with the thermal adhesive  49 , atmosphere remained between the thermal conduction bar  48  and the sidewall of the connection hole  462  can be squeezed out of the connection hole  462 . Thermal resistant between the thermal conduction bar  48  and the ceramic substrate  46  is reduced. In this manner, heat dissipating efficiency of the AC driven LED module  40  is accordingly increased. 
         [0044]      FIG. 5  is schematic cross section of an AC driven LED module in accordance with a fifth embodiment of the present invention. The AC driven LED module  50  of the fifth embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  52 , a first thermal conduction plate  54 , a ceramic substrate  56 , and a thermal conduction bar  58 . The ceramic substrate  56  includes a bottom surface  564 , a top surface  566  opposite to the bottom surface  564 , and a connection hole  562 . The AC driven LED module  50  differs from the AC driven LED module  10  in that the connection hole  562  is a step hole, and the connection hole  562  extends through both of the bottom surface  564  and the top surface  566 . The connection hole  562  includes a first hole portion  561  and a second hole portion  563 . The second hole portion  563  is close to the bottom surface  564 , and the first hole portion  561  is farther from the bottom surface  564 . A diameter of the second hole portion  563  is greater than that of the first hole portion  561 . In assembly, the thermal conduction bar  58  can be moved toward the bottom surface  564  and inserted in the connection hole  562 , and then fixedly attached to the first thermal conduction plate  54  via a screw  55 . As the thermal conduction bar  58  can be moved toward the bottom surface  564  first and then inserted in the connection hole  562 , thus the thermal conduction bar  58  can be assembled after the AC driven LED chip  52 , the first thermal conduction plate  54 , and the ceramic substrate  56  are assembled together. Therefore, assembly of the AC driven LED module  50  is quite convenient. In addition, a wider portion of the thermal conduction bar  58  corresponding to the connection hole  562  is located at a side of the thermal conduction bar  58  close to the bottom surface  564 . With this configuration, the thermal conduction bar  58  can be used to quickly transfer more heat to a portion the ceramic substrate  56  close to the bottom surface  564 . Heat dissipating efficiency of the AC driven LED module  50  thus is further increased. It is noted a thermal adhesive (not shown) also can be provided and filled between the thermal conduction bar  58  and a sidewall of the connection hole  562 . 
         [0045]      FIG. 6  is schematic cross section of an AC driven LED module in accordance with a sixth embodiment of the present invention. The AC driven LED module  60  of the sixth embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  62 , a first thermal conduction plate  64 , a ceramic substrate  66 , and a number of thermal conduction bars  68 . The ceramic substrate  66  defines a number of connection holes  662 . The AC driven LED module  60  differs from the AC driven LED module  10  in that the AC driven LED module  60  includes a number of the connection holes  662  and a number of the thermal conduction bars  68 . 
         [0046]      FIG. 7  is schematic cross section of an AC driven LED module in accordance with a seventh embodiment of the present invention. The AC driven LED module  70  of the seventh embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  72 , a first thermal conduction plate  74 , a ceramic substrate  76 , and a thermal conduction bar  78 . The AC driven LED module  70  differs from the AC driven LED module  10  in that the ceramic substrate  76  is formed on the first thermal conduction plate  74  by injection molding. The ceramic substrate  76  covers the thermal conduction bar  78 , and is arranged at a side of the first thermal conduction plate  74  facing away from the AC driven LED chip  72 . In addition, an end of the thermal conduction bar  78  covered by the ceramic substrate  76  includes a thermal diffusion portion  782 . The thermal diffusion portion  782  is used to increase a surface area of the thermal conduction bar  78  in the ceramic substrate  76  contacting the ceramic substrate  76 . The thermal diffusion portion  782  can be bent. As the ceramic substrate  76  covers the thermal conduction bar  78  by injection molding, the thermal conduction bar  78  intimately contacts the ceramic substrate  76  to avoid air layer formed between the thermal conduction bar  78  and the ceramic substrate  76 . Thus, thermal resistant between the thermal conduction bar  78  and the ceramic substrate  76  can be reduced. Heat dissipating efficiency of the AC driven LED module  70  is accordingly increased. Furthermore, as the end of the thermal conduction bar  78  covered by the ceramic substrate  76  includes the thermal diffusion portion  782 , heat can be accelerated to be dispersed in the ceramic substrate  76 . Accordingly, heat dissipating property of the ceramic substrate  76  can be fully used. Thus, heat dissipating efficiency of the AC driven LED module  70  is further increased. 
         [0047]      FIG. 8  is schematic cross section of an AC driven LED module in accordance with an eighth embodiment of the present invention. The AC driven LED module  80  of the eighth embodiment in the present invention is similar to the AC driven LED module  10 , and includes an AC driven LED chip  82 , a first thermal conduction plate  84 , a ceramic substrate  86 , and a thermal conduction bar  88 . The AC driven LED module  80  differs from the AC driven LED module  10  in that the AC driven LED module  80  further includes a second thermal conduction plate  89 . The ceramic substrate  86  includes a top surface  866 , a bottom surface  864  opposite to the top surface  866 , and a peripheral surface  865 . The peripheral surface  865  is located between and adjoins the top surface  866  and the bottom surface  864 . The first thermal conduction plate  84  is arranged on the top surface  866 . The second thermal conduction plate  89  is arranged below and contacts the bottom surface  864 . The thermal conduction bar  88  is connected to the first thermal conduction plate  84  and the second thermal conduction plate  89 . In detail, the first thermal conduction plate  84  and the thermal conduction bar  88  are integrally manufactured and connected to each other. The second thermal conduction plate  89  and the thermal conduction bar  88  are fixedly attached to each other by a screw  85 . In alternative embodiments, the second thermal conduction plate  89  can be attached to the thermal conduction bar  88  in other ways, only if the first thermal conduction plate  84  and the second thermal conduction plate  89  can be connected to each other through the thermal conduction bar  88 . Material of the second thermal conduction plate  89  is similar as that of the first thermal conduction plate  84  and the thermal conduction bar  88 . In the present invention, material of the second thermal conduction plate  89  is aluminum or copper. As the AC driven LED module  80  further includes the second thermal conduction plate  89 , thus heat dissipating efficiency of the AC driven LED module  80  can be further increased. It is noted, in other alternative embodiments, the second thermal conduction plate  89  can be arranged adjacent to the peripheral surface  865  to contact the peripheral surface  865 , for example. In still other alternative embodiments, either or both of the first thermal conduction plate  84  and the second thermal conduction plate  89 , as well as the thermal conduction bar  88  can be connected to one another in other ways. For example, the first thermal conduction plate  84  and the thermal conduction bar  88  can be fixedly attached to each other via welding or screwing. The second thermal conduction plate  89  and the thermal conduction bar  88  can be integrally manufactured and connected to each other or fixedly attached to each other via welding. The first thermal conduction plate  84 , the second thermal conduction plate  89 , and the thermal conduction bar  88  can be integrally manufactured and connected to one another. 
         [0048]    In summary, the AC driven LED module as described above, as the ceramic substrate has better heat dissipating property and insulation property, thus heat, which is generated by the AC driven LED chip and transferred to the ceramic substrate through the first thermal conduction plate, can be quickly dissipated to ambient environment by the ceramic substrate. In addition, as the AC driven LED module further includes a thermal conduction bar, and the thermal conduction bar has better thermal conductive property, thus shortage of insufficient thermal conductive property of the ceramic substrate can be compensated by the thermal conduction bar. Speed of the heat, which is generated by the AC driven LED chip, transferring from the AC driven LED chip to the ceramic substrate is accelerated, thus heat dissipating efficiency of the AC driven LED is further increased. 
         [0049]    In addition, it is noted in the AC driven LED module as described above, the thermal conduction bar can be omitted when requirement for heat dissipating property is relatively less and a relatively larger contacting area of the first thermal conduction plate and the ceramic substrate is needed. 
         [0050]    While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.