Abstract:
A light-emitting diode (LED) and manufacturing method thereof are disclosed. The LED includes a transparent substrate, a plurality of transparent conductive layers, a plurality of metal circuits, and a LED chip. The LED chip is suitable for emitting a light and a portion of the light emits toward the transparent substrate. The manufacturing method of LED includes the following steps. First, a transparent conductive layer is formed on the transparent substrate. Next, a conductive pattern is fromed by etching transparent conductive layer. The intersection metal circuit is formed by disposing the metal on a portion of the transparent conductive layer. Finally, the LED chip is disposed on the metal circuit so tat the LED chip is electrically connected to the metal circuit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 98140165, filed on Nov. 25, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a light emitting diode (LED) and a manufacturing method thereof More particularly, the present invention relates to a light emitting diode with double-side emission and a manufacturing method thereof 
         [0004]    2. Description of Related Art 
         [0005]    Due to advantages of low power consumption and small volume, LEDs have been extensively applied to fabrication of different sized array light emitting module and applied in indicators in information, communication and consumptive electronic appliances and display devices. 
         [0006]    The light emitting module with double-side emission can be applied in the electronic devices, such as LED advertisement display screens or flip-open type cell phones. The light emitting module with double-side emission may achieve the goal of reducing the manufacturing costs, weight and thickness by using a panel with double-side emission. 
         [0007]    No matter the conventional packaging process of the LED module using the single LED package, the surface-mount device or the flip-chip package, the finished products requires soldering on the printed circuit board to connect the electronic circuit structure in the final steps. However, the light emitting chip is fixed on the non-transparent printed circuit board, and the goal of the double-side emission can not be accomplished. 
         [0008]    In addition, a light emitting module can have a plurality of LED dies with different color, simultaneously. Taking the white LED module of the backlight module as an example, because the white LED module is made with red, green and blue LEDs, the epitaxial materials of different color die are difference, and further the voltage characteristics are difference and the design of the control circuit is more complex. 
         [0009]    Therefore, since the light emitting module requires a complex circuit design to satisfy the demand, the LED module and packaging method thereof can be achieved the goal of double-side emission. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a light-emitting diode with double-side emission and a manufacturing method thereof. 
         [0011]    According to one embodiment of the present invention, a light-emitting diode (LED) is provided. The LED includes a transparent substrate, a first transparent conductive layer, a second transparent conductive layer, a plurality of metal circuits and a LED chip. 
         [0012]    The first transparent conductive layer and the second transparent conductive layer are respectively disposed on a region of the transparent substrate and electrically isolated from each other. The metal circuits are disposed on the first transparent conductive layer and the second transparent conductive layer respectively, and cover the portions of the first transparent conductive layer and the second transparent conductive layer. The LED chip is disposed on the metal circuits and electrically connected to the metal circuits. The LED chip is suitable for emitting a light, and a portion of the light emits toward the transparent substrate. 
         [0013]    According to one embodiment of the present invention, the manufacturing method of LED includes forming a first transparent conductive layer and a second transparent conductive layer by plating a transparent conductive material on the transparent substrate and etching the transparent conductive material. A plurality of metal circuits is respectively disposed on portions of the first transparent conductive layer and second transparent conductive layer. The LED chip is disposed on the metal circuits so that the LED chip is electrically connected to the metal circuits. 
         [0014]    According to another embodiment of the present invention, a LED is provided. The LED includes a transparent substrate, a transparent conductive pattern layer, a first metal circuit, a second metal circuit, an insulating layer and a LED chip. The transparent conductive pattern layer is disposed on the transparent substrate, and the first metal circuit and the second metal circuit on the transparent conductive pattern layer intersect with each other. The insulating layer is disposed between the second metal circuit and the first metal circuit to electrically isolate the first metal circuit and the second metal circuit. The LED chip is disposed on the first metal circuit and the second metal circuit and electrically connected to the first metal circuit and the second metal circuit. The LED chip is suitable for emitting a light, and a portion of the light emits toward the transparent substrate. 
         [0015]    According to one embodiment of the present invention, the manufacturing method of LED includes forming a transparent conductive pattern by plating a transparent conductive material on the transparent substrate and etching the transparent conductive material. The first metal circuit is deposited on a portion of the transparent conductive pattern, and the second metal circuit is deposited on the other portion of the transparent conductive pattern, so that the first metal circuit and the second metal circuit on the transparent conductive pattern layer intersect with each other, and the first metal circuit and the second metal circuit are isolated form each other through the insulating layer disposed between the first metal circuit and the second metal circuit. The LED chip is disposed on the first metal circuit and the second metal circuit and electrically connected to the first metal circuit and the second metal circuit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    In order to make the above and other objects, features and advantages of the present invention more comprehensible, several embodiments accompanied with figures are described in detail below. 
           [0017]      FIG. 1  A is a schematic cross-sectional diagram showing a transparent conductive material layer formed on a transparent substrate according to one embodiment of the present invention. 
           [0018]      FIG. 1B  is a schematic cross-sectional diagram showing a first transparent conductive layer and a second transparent conductive layer formed on the transparent conductive material layer depicted in  FIG. 1A . 
           [0019]      FIG. 1C  is a schematic cross-sectional diagram showing the metal circuits deposited on the first transparent conductive layer and the second transparent conductive layer depicted in  FIG. 1B . 
           [0020]      FIG. 1D  is a schematic cross-sectional view of an LED chip disposed on the metal circuits depicted in  FIG. 1C . 
           [0021]      FIG. 2  is a top view schematically illustrating the LED chip depicted in  FIG. 1D . 
           [0022]      FIG. 3A  is a schematic cross-sectional diagram showing a transparent conductive material layer formed on a transparent substrate according to another embodiment of the present invention. 
           [0023]      FIG. 3B  is a schematic cross-sectional diagram showing a transparent conductive pattern formed on the transparent conductive material layer depicted in  FIG. 3A . 
           [0024]      FIG. 3C  is a schematic cross-sectional diagram showing the metal circuits deposited on the transparent conductive pattern depicted in  FIG. 3B . 
           [0025]      FIG. 3D  is a schematic cross-sectional view of an insulating layer formed on the first metal circuit and the second metal circuit depicted in  FIG. 3C . 
           [0026]      FIG. 3E  is a schematic cross-sectional view of a metal layer formed on the insulating layer depicted in  FIG. 3D  to connect the different sections of the second metal circuit. 
           [0027]      FIG. 3F  is a schematic cross-sectional view of an LED chip disposed on the first metal circuit and the second metal circuit depicted in  FIG. 3E . 
           [0028]      FIG. 4  is schematic views showing an intersection circuit according to the manufacturing flow charts depicted in  FIG. 3A-3F . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0029]      FIGS. 1A-1D  are schematic cross-sectional flowcharts illustrating a manufacturing process of a light-emitting (LED) diode according to an embodiment of the present invention. 
         [0030]    First, as shown in  FIG. 1A , a transparent substrate  100  whereon a transparent conductive material layer  110  has been formed is provided. A method of forming the transparent conductive material layer  110  is, for example, evaporation. A thickness of the transparent conductive material layer  110  can be between 1600˜2100 angstrom (Å), and a resistance of the transparent conductive material layer  110  is 10 ohmic (Ω). 
         [0031]      FIG. 1B  is a schematic cross-sectional diagram showing a first transparent conductive layer and a second transparent conductive layer formed on the transparent conductive material layer depicted in  FIG. 1A . The first transparent conductive layer  113  and the second transparent conductive layer  114  are formed through etching the transparent conductive material layer  110 . The method for etching the transparent conductive material layer  110  is, for example, a lithography and etching process. 
         [0032]      FIG. 1C  is a schematic cross-sectional diagram showing the metal circuits deposited on the first transparent conductive layer and the second transparent conductive layer depicted in  FIG. 1B . The metal circuit  133  is deposited on a portion of the first transparent conductive layer  113 , and the metal circuit  134  is deposited on a portion of the second transparent conductive layer  114 . 
         [0033]      FIG. 1D  is a schematic cross-sectional view of an LED chip disposed on the metal circuits depicted in  FIG. 1C . The LED chip  140  is disposed on the first metal circuit  133  and the second metal circuit  134 , so that the LED chip  140  is electrically connected to the first metal circuit  133  and the second metal circuit  134 . The LED chip  140  is disposed on the metal circuit by flip chip, and the method of disposing includes fixing the LED chip  140  on the metal circuit through a silver glue of a eutectic bonding. 
         [0034]      FIG. 2  is a top view schematically illustrating the LED chip depicted in  FIG. 1D . The cross-sectional structure along line  1 D in  FIG. 2  is as shown in the  FIG. 1D . The LED  150  includes a transparent substrate  100 , a first transparent conductive layer  113 , a second transparent conductive layer  114 , a first metal circuit  133 , a second metal circuit  134  and a LED chip  140 . 
         [0035]    The first transparent conductive layer  113  and the second transparent conductive layer  114  are respectively disposed on a region of the transparent substrate  100  and electrically isolated from each other. The first metal circuit  133  is disposed on the first transparent conductive layer  113  and covers a portion of the first transparent conductive layer  113 . The second metal circuit  134  is disposed on the second transparent conductive layer  114  and covers a portion of the second transparent conductive layer  114 . The LED chip  140  is disposed on the first metal circuit  133  and the second metal circuit  134  and electrically connected to the first metal circuit  133  and the second metal circuit  134 . The LED chip  140  is suitable for emitting a light, and a portion of the light emits toward the transparent substrate. 
         [0036]    According to an embodiment of the present invention, the substrate comprises a glass substrate, a plastic substrate or a flexible substrate. The thickness of the transparent substrate can be 1.1 micrometers (μm). The transparent conductive layer can be a conductive layer with indium tin oxide. The material of the metal circuit is, for example, gold, aluminum, copper, or alloy thereof. 
         [0037]      FIGS. 3A-3F  are schematic cross-sectional flowcharts illustrating a manufacturing process of a light-emitting diode (LED) according to another embodiment of the present invention. 
         [0038]      FIG. 3A  is a schematic cross-sectional diagram showing a transparent conductive material layer formed on a transparent substrate. A transparent conductive material  210  is plated on a transparent substrate  200 . A method of forming the transparent conductive material  210  is, for example, evaporation. A thickness of the transparent conductive material  210  can be between 1600˜2100 angstrom (Å), and a resistance of the transparent conductive material layer  210  is 10 ohmic(Ω). 
         [0039]      FIG. 3B  is a schematic cross-sectional diagram showing a transparent conductive pattern formed by etching the transparent conductive material layer  210 . Patterns  212   a ,  212   b ,  212   c  are formed by etching the transparent conductive material layer  210 . The method for etching the transparent conductive material layer  210  is, for example, a lithography and etching process. 
         [0040]      FIG. 3C  is a schematic view of the metal circuits deposited on the transparent conductive pattern  212 . The first metal circuit  222  is deposited on a portion of the pattern  212   c  of the transparent conductive pattern, the section  223   a  of the second metal circuit  223  is deposited on a portion of the pattern  212   a , and the section  223   b  of the second metal circuit is deposited on a portion of the pattern  212   b.    
         [0041]      FIG. 3D  is a schematic view of an insulating layer formed on the first metal circuit  222 . The insulating layer  230  covers a portion of the first metal circuit  222  and extends crossing a portion of the sections  223   a ,  223   b  of the second metal circuit  223 . 
         [0042]      FIG. 3E  is a schematic view of a metal layer formed on the insulating layer to connect the sections  223   a ,  223   b  of the second metal circuit  223 . A metal layer is deposited on a portion of the insulating layer  230 , the sections  223   a ,  223   b  of the second metal circuit  223  to form a connecting section  240  to connect the sections  223   a ,  223   b  of the second metal circuit  223 . The first metal circuit  222  and the second metal circuit  223  on the transparent conductive pattern layer intersect with each other by the connecting section  240 . The insulating layer  230  is disposed between the first metal circuit  222  and the second metal circuit  223  to electrically isolate the first metal circuit  222  and the second metal circuit  223 . 
         [0043]      FIG. 3F  is a schematic view of an LED chip disposed on the first metal circuit and the second metal circuit. The first metal circuit  222  and the second metal circuit  223  respectively extend and connect to a positive electrode and a negative electrode, and the LED chip  140  is disposed on the positive electrode and the negative electrode so as to electrically connect to the first metal circuit  222  and the second metal circuit  223 . 
         [0044]      FIG. 4  is schematic views showing an intersection circuit according to the manufacturing flow charts depicted in  FIG. 3A-3F . The intersection circuit  300  includes a transparent substrate  200 , a transparent conductive pattern layer  212 , a first metal circuit  222  and a second metal circuit  223 , an insulating layer  230  and a LED chip  400 . The transparent conductive pattern layer  212  is disposed on the transparent substrate  200 , and the first metal circuit  222  and the second metal circuit  223  on the transparent conductive pattern layer  212  intersect with each other. The insulating layer  230  is disposed between the second metal circuit  223  and the first metal circuit  222  to electrically isolate the first metal circuit  222  and the second metal circuit  223 . 
         [0045]    The LED chip  400  is disposed on the first metal circuit  222  and the second metal circuit  223  and electrically connected to the first metal circuit  222  and the second metal circuit  223 . The LED chip  400  is disposed on the metal circuits by flip chip, and the method of disposing includes fixing the light emitting chip on the metal circuit through a silver glue of a eutectic bonding. The LED chip  400  is suitable for emitting a light, and a portion of the light emits toward the transparent substrate. 
         [0046]    According to an embodiment of the present invention, the substrate comprises a glass substrate, a plastic substrate or a flexible substrate. The thickness of the transparent substrate can be 1.1 micrometers (μm). The transparent conductive layer can be a conductive layer with indium tin oxide. The material of the metal circuit is, for example, gold, aluminum, copper, or alloy thereof. A material of the insulating layer is, for example, silicon oxide, nitride dioxide or a common-used insulating material. 
         [0047]    It should be noted that the above-mentioned first metal circuit, the second metal circuit, the insulating layer, the metal circuit pattern or the shape, the position, the size and the amount, the located of the positive electrode and the negative electrode of light emitting chip only serves as an example and is not intended to limit the present invention. 
         [0048]    Although the present invention has been disclosed above by the embodiments, they are not intended to limit the present invention. Anybody skilled in the art can make some modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the protecting range of the present invention falls in the appended claims.