Abstract:
The invention discloses a light-emitting diode lamp with high heat dissipation that uses the high heat conductible material to make the lamp cavity and coordinates with the design of directly adhering base of the flip-chip light-emitting diodes and the cavity to achieve the purpose of guiding light and dissipating heat. The flip-chip light-emitting diode is used and arranged in matrix, the brightness and the uniformity can be effectively improved. The present invention can be applied to be the light source of the liquid crystal display, the advertisement board, the scanner and so on.

Description:
BACKGROUND OF INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a light-emitting diode lamp, and more particularly, to a light-emitting diode lamp with high heat dissipation.  
         [0003]     2. Description of the Prior Art  
         [0004]     The back light module, or named back light, is popularly applied to provide light source for the liquid crystal, such as the liquid crystal display, the cell phone panel, the advertisement board and so on. The liquid crystal material has good molecule alignment and mobile characteristic, and when irritated by the light, heat, electric field or magnetic field, the molecule alignment will be easily changed to allow the light passing through and form a gray-level contrast or other electric optical effect. But the liquid crystal material is not a self-emitting material, and an external light source is needed to display. Therefore, the light-guide module with back light or front light is provided as the external light source of the liquid crystal.  
         [0005]     Generally, the light source of the light-guide module with back light or front light is cold cathode fluorescent lamp (CCFL), but the request for high voltage and alternating current power source of CCFL is an inconvenient disadvantage for the portable liquid crystal display. Subsequently, the lamp, or called light-guide tube, utilizing the light-emitting diodes as light source is developed. The light-emitting diodes are installed on one or both sides of the lamp and can luminesce in coordination with the light-guide design in the lamp. The light-emitting diode is generally a surface mount device light-emitting diode (SMD-LED) or a lamp light-emitting diode (Lamp-LED), and has the advantages of smaller volume, longer lifetime, and lighter weight and without the alternating current power source.  
         [0006]     However, the lamp using the SMD-LED and the Lamp-LED as the light source still has some disadvantages. Firstly, for enhancing the brightness, the amount of the light-emitting diodes is always increased. But the entire lamp space is limited, and the brightness is restrictedly improved with the restrictedly increased light-emitting diodes. Secondly, regarding to the efficiency of heat dissipation, although the brightness can be also improved by raising the driving current of the light-emitting diode or using high-brightness light-emitting diode, the extra thermal energy will obstruct the efficiency of heat dissipation. Thirdly, regarding to the uniformity of the light, the SMD-LED and the Lamp-LED need larger space in the lamp, so the light has a worse uniformity.  
         [0007]     In addition, illustrating with the Lamp-LED, the heat resistance is about 200° C./W, and that means 200° C. is produced when inputting 1 W. Under this high temperature, the epoxy resin will degrade, and the reliability is influenced and the input power is limited. Hence, how to lower the heat resistance and enhance the heat dissipation is an important target, especially to the product with high input power.  
         [0008]     For solving the above-mentioned disadvantages, the present invention provides a light-emitting diode lamp with high heat dissipation. The light-emitting diode lamp has a better heat dissipation with using material of high heat conductivity as the lamp cavity. The light-emitting diode lamp further uses the flip-chip light-emitting diodes arranged in matrix as the light source, and can greatly improve the electric input power and increase the light output power. No matter increase amount of the light-emitting diode or raising the input current, the present invention can provide a better light uniformity.  
       SUMMARY OF INVENTION  
       [0009]     The purpose of present invention provides a lamp with high heat dissipation that uses the high heat conductible cavity to provide better heat dissipation.  
         [0010]     Further, the purpose of present invention provides a lamp with high brightness and uniformity that uses the flip chip light-emitting diodes arranged in matrix to overcome the limitation of the arrangement space and improve the brightness and the uniformity.  
         [0011]     Furthermore, the purpose of present invention provides a high efficiency lamp that utilizes high heat conductible cavity and the flip-chip light-emitting diodes arranged in high-density matrix to accomplish the great uniformity without requiring the precise optical system.  
         [0012]     Furthermore, the purpose of present invention provides a lamp with high heat dissipation that utilizes the flip-chip light-emitting diodes arranged in matrix and the submount directly mounted on the lamp cavity to achieve the great heat dissipation.  
         [0013]     Furthermore, the purpose of present invention provides a lamp with high heat dissipation that raises the input electric power to enhance the output optical power.  
         [0014]     Furthermore, the purpose of present invention provides a lamp with high heat dissipation and high safety that using isolative and high heat conductive base and cavity to dissipate heat, and the electric power is supplied from top of the base and is isolated from the cavity that preventing electric leakage.  
         [0015]     The present invention discloses a high heat conductible cavity on which equipped a rectangular opening and a transparent cover, and flip chip light-emitting diodes arranged in matrix for providing the light source. The entire design has not only good heat dissipation but also high brightness uniformly luminescing through the transparent cover.  
         [0016]     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0017]      FIG. 1  is a structural graph of a preferred embodiment according to the present invention.  
         [0018]      FIG. 2  is an exploded structural graph of a preferred embodiment according to the present invention.  
         [0019]      FIG. 3  is a structural side view of a preferred embodiment according to the present invention.  
         [0020]      FIG. 4  is a structural graph of a light-emitting diode according to the present invention.  
         [0021]      FIG. 5  is a structural graph of another embodiment according to the present invention.  
         [0022]     FIGS.  6 ( a ) and  6 ( b ) are schematic graphs of power conduction designs on the base of the flip-chip light-emitting diode according to the present invention.  
         [0023]      FIG. 6 ( c ) is a structural graph enlarged the bakelite and the copper pillar in  FIG. 6 ( b ).  
     
    
       [0024]      10  light-emitting diode lamp  
         [0025]      12  heat conductible cavity  
         [0026]      14  transparent cover  
         [0027]      16  light-emitting diode 
         160  flip-chip light-emitting diode      162  light-emitting diode chip      164  base          
         [0031]      18  rectangular opening  
         [0032]      20  reflective pattern  
         [0033]      22  chamber  
         [0034]      24  fluorescent powder  
         [0035]      26  epoxy resin  
         [0036]      28  power line  
         [0037]      30  cavity hole  
         [0038]      32  bakelite  
         [0039]      34  copper pillar  
       DETAILED DESCRIPTION  
       [0040]     The present invention is a light-emitting diode lamp with high heat dissipation that is used to improve the disadvantages of brightness and heat dissipation of the conventional lamp.  
         [0041]     Please refer to  FIGS. 1 and 2 , which are a structural diagram and an exploded structural diagram of a preferred embodiment according to the present invention. As shown in figures, a light-emitting diode lamp  10  with high heat dissipation comprises a heat conductible cavity  12 , a transparent cover  14  and a plurality of light-emitting diodes  16 . The heat conductible cavity  12  is made by material with high heat conductivity, such as metal or ceramics. Since material of the heat conductible cavity  12  has better heat conductivity, the entire lamp  10  will also have better heat dissipation. When choosing material of the heat conductible cavity  12  among all kinds of metals, aluminum is the preferred one as its low cost and high heat conductivity. A rectangular opening  18  is further formed on the heat conductible cavity  12  for the light passing, and a reflective pattern  20  is formed under the cavity  12  corresponding to the opening  18  to reflect and uniform the light. The reflective pattern  20 , such as circular dot pattern, rectangular fillister pattern, slanting V-shaped continuous fillister pattern, V-shaped continuous fillister pattern and V-shaped intermittent fillister pattern, can enhance the refraction and uniform the light. The transparent cover  14  is equipped on the rectangular opening  18  to form a chamber  22  with the heat conductible cavity  12 . The transparent cover  14  such as a condensing lens can condense the light to improve the brightness, and always being designed in arc-shaped and made by transparent material to enhance the condensation and transmittance. A plurality of light-emitting diodes  16  is installed on one or both ends of the heat conductible cavity  12  to be the light source. Please refer to  FIG. 3 , wherein the adhesion of the light-emitting diode  16  and the heat conductible cavity  12  can further utilize a high heat conductible material, such as tin grease or silver glue, to improve the heat dissipation and achieve the effect of high brightness and high heat dissipation.  
         [0042]     The light-emitting diode  16  can be the flip-chip light-emitting diode  160  shown in  FIG. 4 . The flip-chip light-emitting diode  160  includes a light-emitting diode chip  162  and a base  164 , and the light-emitting diode  162  is mounted on the base  164  with a flip-chip way. The base  164  has a function of supplying power, whose material can be ceramics as AlN, BeO, or Al 2 O 3 , or isolative silicon material. The materials with high heat conductivity and the coefficient of expansion similar to the light-emitting diode chip  162  are all suitable. The base  164  is made with a high heat conductivity material, so the heat resistance is small and the power efficiency can be improved.  
         [0043]     In addition, on the base of the flip-chip light-emitting diode, the power supply method is isolating the cavity to prevent getting an electric shock, and is explained with two followed embodiments. As shown in  FIG. 6  ( a ), the external power line  28  is welded on the base of the flip-chip light-emitting diode via a cavity hole  30 , and the power line  28  is wrapped with plastic to isolate to the cavity  12 . Or as shown in  FIG. 6  ( b ) and its partially enlarged graph in  FIG. 6 ( c ), a copper pillar  34  whose outer edge covered with an isolative bakelite  32  is adhered on the cavity  12 , and the copper pillar  34  is used for conducting the power. Such kinds of conduction ways are too numerous to enumerate.  
         [0044]     The flip-chip light-emitting diode  160  uses the light-emitting diode chips whose size are smaller than that of the packaged surface-mounted light-emitting diode. So the flip chip light-emitting diode can be arranged in high-density matrix, and the brightness can be improved without increasing the driving current of the light-emitting diodes. In addition, the requirement of the optical system is slacker. The present invention uses a plurality of light-emitting diode chips with big size to compose a single flip-chip light-emitting diode.  
         [0045]     The light-emitting diode used in the present invention can be any color of light-emitting diodes, such as red light, white light, blue light, violet light, ultraviolet light, green light and so on.  
         [0046]     Please refer to  FIG. 5 , which is a structural diagram of another embodiment according to the present invention. For improving the efficiency of the claimed light-emitting diode lamp  10 , except forming the reflective pattern  20 , a reflective film (not shown) can be further equipped at the inner periphery of the heat conductible cavity  12  to improve the refractive efficiency. If the white light is desired, a layer of fluorescent powder  24  can be coated on the inner surface of the transparent cover  14  or stuffed in the chamber  22 . Furthermore, the chamber  22  can be further stuffed with epoxy resin  26  to enhance the light.  
         [0047]     In contrast to the prior art, the present invention using the material of high heat conductivity to be the cavity  12  can solve the conventional problem of worse heat dissipation. The light-emitting diode lamp  10  with high heat dissipation uses a plurality of light-emitting diodes  16  to be the light source. By means of the reflective pattern  20  under the lamp  12  and the reflective film in the cavity can enhance the uniformity of the light. The fluorescent powder  24  coated on the inner surface of the transparent cover  14  or stuffed in the chamber  22  can reinforce the light energy to be the white light. Then the rectangular opening  18  and the transparent cover  14  on the lamp  12  can condense the light to improve the brightness. Since the high efficient light-emitting diodes will produce much thermal energy while radiating, the present invention directly adheres the base of the flip-chip light-emitting diode and the cavity to conduct heat, and uses material with high heat conductivity, such as metal and ceramics, to be the cavity to dissipate heat rapidly. In addition, the present invention uses materials of metal, ceramics or semiconductor that can improve the crack situation of the plastic material after irradiated by the violet light or the ultraviolet light.  
         [0048]     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.