Abstract:
The present invention discloses a thin-film transistor (TFT), a liquid crystal display (LCD) panel and method for manufacturing the same. In the LCD panel, a transparent conducting layer forms a first electrode of a TFT and a second electrode of a TFT directly, and the transparent conducting layer also serves as a connecting line between a TFT and a data line and between a TFT and an LC capacitor. So it is not necessary to form a via hole over the TFT to link the TFT and the transparent conducting layer. In this way, an area of a pixel electrode can be further extended, and the aperture rate of an LCD panel can be also increased, raising a transmittance of light from light sources passing through the pixel electrode In this way, not only a design in pixels becomes more flexible but also the aperture rate of an LCD panel becomes higher.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a liquid crystal display (LCD) panel, and more particularly, to a thin-film transistor (TFT), an LCD panel and method for manufacturing the same where a transparent conducting layer is directly connected to a data line and a switch unit. 
         [0003]    2. Description of Prior Art 
         [0004]    An advanced monitor with multiple functions is an important feature for use in current consumer electronic products. Liquid crystal displays (LCDs) which are colorful monitors with high resolution are widely used in various electronic products such as monitors for mobile phones, personal digital assistants (PDAs), digital cameras, laptop computers, and notebook computers. 
         [0005]    An LCD panel of a conventional LCD comprises a plurality of pixels. Each pixel comprises three pixel units representing the three primary colors of light—Red (R), Green (G), and Blue (B). Referring to  FIG. 1  showing a schematic diagram of a pixel unit  10  of a conventional LCD panel, when a gate driver (not shown) outputs a scan signal through scan line  11  to activate each thin film transistor (TFT) of the pixel units  10  in each row in sequence, a source driver outputs corresponding data signals through data lines  12  to the pixel units in a straight row. The pixel units  10  are charged to obtain required voltage and display different gray levels. The gate driver outputs a scan signal row by row to turn on each TFT  13  of the pixel units in each row. Then, the source driver charges/discharges the turned-on pixel units in each row. Based on this sequence, all of the pixel units  10  on the LCD panel are charged. After all of the pixel units are completely charged, the pixel units  10  in the first row start to be charged again. 
         [0006]    Refer to  FIG. 2  and  FIG. 1  simultaneously.  FIG. 2  is a cross section view along a line from point A to point B to point C in  FIG. 1 . As  FIG. 2  shows, between point A and point B, a gate  131  of a TFT  13  is formed by a first metal layer, and source  132 , and a drain  133  of a TFT  13  are formed by a second metal layer. A bottom electrode plate  141  of a storage capacitor Cst is also formed by a first metal layer between point B and point C. A transparent conducting layer  15  between the TFT  13  and the storage capacitor Cst serves as a pixel electrode. 
         [0007]    Please refer to  FIGS. 3 to 7 , which illustrate diagrams of the manufacturing process for completing the structure shown in  FIG. 2 . Each of the figures represents a mask process. In other words, it requires five mask processes to complete the structure illustrated in  FIG. 2 . 
         [0008]    Refer to  FIG. 3 . During this stage of the manufacturing process, the first metal layer (not shown) is deposited on a glass substrate  101 . Meanwhile, a developing process is conducted through a first mask. The developing process contains the following steps: coating a photoresist (not shown) on the first metal layer, exposing the photoresist through the first mask having a specific pattern, and then washing out the exposed photoresist with a developer. Afterwards, the first metal layer undergoes an etching process. The etching process includes the steps of: removing the first metal layer which is not covered by the photoresist by using strong acid, forming a bottom electrode plate  141  used as the gate  131  and the storage capacitor Cst of the TFT  13  as shown in  FIG. 3  by reserving the first metal layer covered by the photoresist (roughly showing the specific pattern), and washing out the remaining photoresist. 
         [0009]    Refer to  FIG. 4 . During this stage of the manufacturing process, firstly, an isolation layer  16  is deposited. Secondly, an active layer  17  is deposited thirdly, an n+ layer  18  are deposited. Finally, a developing process is conducted through a second mask. Meanwhile, the active layer  17  and the ohmic contact layer  18  undergo an etching process. 
         [0010]    Refer to  FIG. 5 . During this stage of the manufacturing process, firstly, the second metal layer (not shown) is deposited. Next, a developing process is conducted through a third mask. Meanwhile, the second metal layer and the ohmic contact layer  18  undergo an etching process to form the drain  132  and the source  133  of the TFT  13  and a data line  12 . 
         [0011]    Refer to  FIG. 6 . During this stage of the manufacturing process, firstly, a passivation layer  19  is deposited. Next, a developing process is conducted through a fourth mask. Meanwhile, the passivation layer  19  undergoes an etching process in order to form a via  20  on top of the source  133 . 
         [0012]    At last, refer to  FIG. 7 . During this stage of the manufacturing process, firstly, the transparent conducting layer  15  is deposited. Next, a developing process is conducted through a fifth mask. Meanwhile, transparent conducting layer  15  undergoes an etching process in order to form a structure as shown in  FIG. 7 . The basic structure of the LCD panel  10  up to here is complete. 
         [0013]    However, the structure of the LCD panel  10  and its related process technology still has room to improve. For instance, an increase in an aperture rate of the pixel is necessary to increase the overall transmittance of a panel. 
       SUMMERY OF THE INVENTION 
       [0014]    An objective of the present invention is to provide a method of forming a liquid crystal display (LCD) panel, an LCD panel and a thin film transistor thereof to raising an aperture ratio of the LCD panel to improve a transmittance of the LCD panel. 
         [0015]    In one aspect of the present invention, a method of forming a liquid crystal display (LCD) panel comprises: a glass substrate is provided; a first metal layer formed on the glass substrate is etched to form a data line; a first passivation layer and a second metal layer are deposited on the glass substrate and on the first metal layer in order; the second metal layer is etched to form a control electrode of a switch unit; an isolation layer and an active layer are deposited on the first passivation layer and on the second metal layer in order; the active layer is etched simultaneously for reserving the active layer above the control electrode, and the active layer serves as a channel of the switch unit; the first passivation layer and the isolation layer above the data line are etched to form a via hole on top of the data line; a transparent conducting layer is deposited on the isolation layer, the data line, and the active layer; and the transparent conducting layer is etched to divide the transparent conducting layer into a first transparent conducting layer and a second transparent conducting layer, wherein the data line is electrically connected to the active layer through the first transparent conducting layer on the via hole, and the active layer is electrically connected to the second transparent conducting layer. 
         [0016]    In another aspect of the present invention, an LCD panel comprises: a glass substrate; a first metal layer, disposed on the glass substrate, for forming a data line; a first passivation layer, disposed on the glass substrate and on the first metal layer; a second metal layer, disposed on the first passivation layer, for forming a control electrode of a switch unit; an isolation layer, disposed on the first passivation layer and the second metal layer; an active layer, disposed on the isolation layer, for functioning as a channel of the switch unit; a via hole, formed on top of the data line; and a transparent conducting layer, disposed on the isolation layer and on the via hole, comprising a first transparent conducting layer and a second transparent conducting layer, the first transparent conducting layer electrically connected to the data line, the second transparent conducting layer functioning as a pixel electrode. Upon receiving a scan voltage by the control electrode, a data voltage from the data line is transmitted to the second transparent conducting layer through the first transparent conducting layer and the active layer. 
         [0017]    In still another aspect of the present invention, a transistor formed on a glass substrate comprises: a first passivation layer disposed on the glass substrate; a metal layer disposed on the first passivation layer and the substrate, for forming a gate of the transistor; an isolation layer, disposed on the metal layer; an active layer, disposed on the isolation layer, for functioning as a channel of the transistor; and a transparent conducting layer with an opening thereon to divide a first transparent conducting layer and a second transparent conducting layer. The first transparent conducting layer functions as a first electrode for inputting or outputting an electrical signal while the second transparent conducting layer functions as a second electrode for inputting or outputting the electrical signal. 
         [0018]    In still another aspect of the present invention, a method of forming a liquid crystal display (LCD) panel comprises: a glass substrate is provided; a first metal layer formed on the glass substrate is etched to form a control electrode of a switch unit; a first passivation layer and a second metal layer are deposited on the glass substrate and on the first metal layer in order; the second metal layer is etched to form a data line; an isolation layer and an active layer are deposited on the first passivation layer and on the second metal layer in order; the active layer is etched simultaneously for reserving the active layer above the control electrode, and the active layer serves as a channel of the switch unit; the first passivation layer and the isolation layer above the data line are etched to form a via hole on top of the data line; a transparent conducting layer is deposited on the isolation layer, the data line, and the active layer; and the transparent conducting layer is etched to divide the transparent conducting layer into a first transparent conducting layer and a second transparent conducting layer, wherein the data line is electrically connected to the active layer through the first transparent conducting layer on the via hole, and the active layer is electrically connected to the second transparent conducting layer. 
         [0019]    In yet another aspect of the present invention, a LCD panel comprises: a glass substrate; a first metal layer, disposed on the glass substrate, for functioning as a control electrode of a switch unit; a first passivation layer, disposed on the glass substrate and on the first metal layer; a second metal layer, disposed on the first passivation layer, for forming a data line; an isolation layer, disposed on the first passivation layer and the second metal layer; an active layer, disposed on the isolation layer, for functioning as a channel of the switch unit; a via hole, formed on top of the data line; and a transparent conducting layer, disposed on the isolation layer and on the via hole, comprising a first transparent conducting layer and a second transparent conducting layer, the first transparent conducting layer electrically connected to the data line, the second transparent conducting layer functioning as a pixel electrode. Upon receiving a scan voltage by the control electrode, a data voltage from the data line is transmitted to the second transparent conducting layer through the first transparent conducting layer and the active layer. 
         [0020]    In yet another aspect of the present invention, a transistor formed on a glass substrate comprises: a metal layer disposed on the glass substrate for forming a gate of the transistor; a first passivation layer disposed on the first passivation layer and the glass substrate; an isolation layer, disposed on the metal layer; an active layer, disposed on the isolation layer, for functioning as a channel of the transistor; and a transparent conducting layer with an opening thereon to divide a first transparent conducting layer and a second transparent conducting layer. The first transparent conducting layer functions as a first electrode for inputting or outputting an electrical signal while the second transparent conducting layer functions as a second electrode for inputting or outputting the electrical signal. 
         [0021]    In contrast to the prior art, the LCD panel and method for manufacturing the same of the present invention can produce LCD panels with a new TFT structure using a five-mask process. In the LCD panel, a transparent conducting layer forms a first electrode and a second electrode of a TFT directly. Meanwhile, the transparent conducting layer also serves as a connecting line between a TFT and a data line and between a TFT and an LC capacitor, without forming a via hole over the TFT to link the TFT and the transparent conducting layer. In this way, an area of a pixel electrode can be further extended, and the aperture rate of an LCD panel can be also increased, raising a transmittance of light from light sources passing through the pixel electrode. 
         [0022]    These and other features, aspects and advantages of the present disclosure will become understood with reference to the following description, appended claims and accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  shows a schematic diagram of a pixel unit of a conventional LCD panel. 
           [0024]      FIG. 2  is a cross section view along a line from point A to point B to point C in  FIG. 1 . 
           [0025]      FIGS. 3 to 7  illustrate diagrams of the manufacturing process for completing the structure shown in  FIG. 2 . 
           [0026]      FIGS. 8 to 16  illustrate schematic diagram of the LCD panel manufacturing process according to a first embodiment of the present invention. 
           [0027]      FIG. 17  is a structure diagram of an LCD panel according to the present invention. 
           [0028]      FIGS. 18 to 26  are schematic diagrams of the LCD panel manufacturing process according to a second embodiment of the present invention. 
           [0029]      FIG. 27  is a structure diagram of an LCD panel according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. 
         [0031]    Refer to  FIGS. 8 to 16 , which illustrate schematic diagram of the LCD panel manufacturing process according to a first embodiment of the present invention. Firstly, refer to  FIG. 8 . During this stage of the manufacturing process, firstly, a first metal layer (not shown) is deposited on a glass substrate  201 . Meanwhile, a developing process is conducted through a first mask. The developing process contains the following steps: coating a photoresist (not shown) on the first metal layer, exposing the photoresist through the first mask having a specific pattern, and then washing out the exposed photoresist with a developer. Afterwards, the first metal layer undergoes an etching process. The etching process includes the steps of: removing the first metal layer which is not covered by the photoresist with a strong producing a data line  22  on the first metal layer covered by the photoresist (roughly showing the specific pattern), and washing out the remaining photoresist. 
         [0032]    Refer to  FIG. 9 . During this stage of the manufacturing process, firstly, a first passivation layer  24  is deposited on the glass substrate  201  and the first metal layer. Next, a second metal layer (not shown) is deposited on the first passivation layer  24 . Next, a developing process is conducted through a second mask. Meanwhile, the second metal layer undergoes an etching process in order to generate a control electrode  261 . 
         [0033]    Refer to  FIG. 10 . During this stage of the manufacturing process, firstly, an isolation layer  28  is deposited on the control electrode  261  and the first passivation layer  24 . Next, an active layer and an ohmic contact layer are deposited on the isolation layer  28  in order. Subsequently, a developing process is conducted through a third mask. Meanwhile, the active layer  30  and the ohmic contact layer  32  undergo an etching process in order to reserve the active layer  30  and the ohmic contact layer  32  corresponding to the top of the control electrode  261 . 
         [0034]    Refer to  FIG. 11 . During this stage of the manufacturing process, a developing process is conducted through a fourth mask. Meanwhile, the isolation layer  28  and the first passivation layer  24  undergo an etching process until the data line  22  is exposed and a via hole  34  is formed. 
         [0035]    Refer to  FIG. 12 . During this stage of the manufacturing process, firstly, a transparent conducting layer  36  is deposited. Next, a layer of photoresist  38  is coated on top of the transparent conducting layer  36 . 
         [0036]    Refer to  FIG. 13 . During this stage of the manufacturing process, the photoresist  38  is exposed through a fifth mask  40 . After the photoresist  38  is radiated by the ultraviolet light, part of photoresist  38  which is not covered by the fifth mask  40  changes its solubility to a developer. So the exposed photoresist  38  can be easily washed out with the developer. 
         [0037]    Refer to  FIG. 14 . During this stage of the manufacturing process, part of the transparent conducting layer  36  and the ohmic contact layer  32 , where the photoresist  38  does not cover, is removed by performing an etching process to form an opening  42 . The opening  42  is formed on top of the control electrode  261 . The ohmic contact layer  32  at both sides of the opening  42  forms a first ohmic contact layer  321  and a second ohmic contact layer  322 , respectively. 
         [0038]    Refer to  FIG. 15 . During this stage of the manufacturing process, a second passivation layer  44  is deposited on the remaining photoresist  38  and inside the opening  42  before the rest of photoresist  38  is removed. 
         [0039]    Refer to  FIG. 16 . During this stage of the manufacturing process, both of the photoresist  38  and the second passivation layer  44  deposited on the photoresist  38  are lifted off. The second passivation layer  44  inside the opening  42  is prevented from being lifted off because it does not adhere to the photoresist  38 . Thus, the second passivation layer  44  adheres to the inner surface of the opening  42  and to the top of the active layer  30  corresponding to the opening  42 . 
         [0040]    Refer to  FIG. 17 , which is a structure diagram of an LCD panel  50  according to the present invention. The LCD panel  50  comprises a glass substrate  201  and a glass substrate  202 . An LC layer  250  is injected onto the glass substrate  201  on which the data line  22  and the switch unit  52  are arranged, and then the glass substrate  202  having a black matrix  242  and a color filter  244  covers the LC layer  250 . Another transparent electrode layer  240  covers the black matrix  242  and the color filter  244 . A common voltage is applied to the transparent electrode layer  240  functioning as a common voltage electrode layer. The transparent conducting layer  36  is divided into a first transparent conducting layer  36   a  and a second transparent conducting layer  36   b  by the opening  42 . The switch unit  52  can equivalently act as the TFT which controls data signals transmitted from the data line  22 . In other words, the control electrode  261  of the switch unit  52  can act as a gate of the TFT. Practically, the first transparent conducting layer  36   a  and the second transparent conducting layer  36   b  serve as a first electrode and a second electrode of the switch unit  52 , respectively. The first transparent conducting layer  36   a  and the second transparent conducting layer  36   b  can also serve as a source (a drain) of the TFT and a drain (a source) of the TFT, respectively. The active layer  30  serves as a channel between the drain of the switch unit  52  and the source of the switch unit  52 . The first transparent conducting layer  36   a,  functioning as a first electrode, is capable of outputting or inputting electrical signals. Correspondingly, the second transparent conducting layer  36   b,  functioning as a second electrode, is capable of inputting or outputting electrical signals. An object of the second passivation layer  44  adhering to the opening  42  is to separate the ohmic contact layer  32  from the active layer  30  functioning as a channel, so that the active layer  30  and the ohmic contact layer  32  are prevented from approaching the LC layer  250  directly and further from affecting the alignment of LC molecules. According to this embodiment, the second transparent conducting layer  36   b  serves as not only a second electrode of the TFT  52  but also, practically, a pixel electrode. Practically, an LC capacitor  56  is formed by an overlap of the pixel electrode and the transparent conducting layer  240 . Upon receiving a scanning voltage with the control electrode  52 , a data voltage transmitted from the data line  22  is transmitted to the second transparent conducting layer  36   b  (i.e., the pixel electrode) through the first transparent conducting layer  36   a  and the switch unit  52 . The alignment of the LC molecules of the LC layer  250  are adjusted according to a voltage difference between the data voltage applied on the second transparent conducting layer  36   b  and the common voltage applied on the transparent electrode layer  240 , which decides the transmittance of light beams. 
         [0041]    Refer to  FIG. 16 . The TFT  52  is formed on the glass substrate  201  according to the present embodiment. The TFT  52  comprises the first passivation layer  24  disposed on the glass substrate  201 , the gate  261  disposed on the first passivation layer  24 , the isolation layer  28  disposed on the gate  261 , the active layer  30  disposed on the isolation layer  28  and functioning as a channel of the TFT  52 , and the ohmic contact layer  32  disposed on the active layer  30  and having the opening  42 . The ohmic contact layer  32  at both sides of the opening  42  forms the first ohmic contact layer  321  and the second ohmic contact layer  322 , respectively. The transparent conducting layer  36  at both sides of the opening  42  forms the first transparent conducting layer  36   a  and the second transparent conducting layer  36   b , respectively. The first transparent conducting layer  36   a  is connected to the first ohmic contact layer  321  and serves as the first electrode for outputting or inputting electrical signals. The second transparent conducting layer  36   b  is connected to the second ohmic contact layer  322  and serves as the second electrode for outputting or inputting electrical signals. 
         [0042]    According to a preferred embodiment, the first ohmic contact layer  321  and the second ohmic contact layer  322  of the ohmic contact layer  32  is used for decreasing the resistance of the TFT  52 . According to another embodiment, the ohmic contact layer  32  is unnecessary during the manufacturing process, so the first ohmic contact layer  321  and the second ohmic contact layer  322  are not necessary for the LCD panel  50  and the TFT  52 . 
         [0043]    Refer to  FIGS. 18 to 26 , which are schematic diagrams of the LCD panel manufacturing process according to a second embodiment of the present invention. Firstly, refer to  FIG. 18 . During this stage of the manufacturing process, firstly, a first metal layer (not shown) is deposited on a glass substrate  601 . Meanwhile, a developing process is conducted through a first mask. Afterwards, the first metal layer is etched to generate a control electrode  661  of a switch unit. 
         [0044]    Refer to  FIG. 19 . During this stage of the manufacturing process, firstly, a first passivation layer  64  is deposited on the glass substrate  601  and the first metal layer. Next, a second metal layer (not shown) is deposited on the first passivation layer  64 . Next, a developing process is conducted through a second mask. Meanwhile, the second metal layer undergoes an etching process in order to generate a data line  62 . 
         [0045]    Refer to  FIG. 20 . During this stage of the manufacturing process, firstly, an isolation layer  68  is deposited on the control electrode  661  and the first passivation layer  64 . Next, an active layer and an ohmic contact layer are deposited on the isolation layer  68  in order. Subsequently, a developing process is conducted through a third mask. Meanwhile, the active layer and the ohmic contact layer undergo an etching process in order to reserve the active layer  70  and the ohmic contact layer  72  corresponding to the top of the control electrode  661 . 
         [0046]    Refer to  FIG. 21 . During this stage of the manufacturing process, a developing process is conducted through a fourth mask. Meanwhile, the isolation layer  68  undergo an etching process until the data line  62  is exposed and a via hole  74  is formed. 
         [0047]    Refer to  FIG. 22 . During this stage of the manufacturing process, firstly, a transparent conducting layer  76  is deposited. Next, a layer of photoresist  78  is coated on top of the transparent conducting layer  76 . 
         [0048]    Refer to  FIG. 23 . During this stage of the manufacturing process, the photoresist  78  is exposed through a fifth mask  90 . After the photoresist  78  is radiated by the ultraviolet light, part of photoresist  78  which is not covered by the fifth mask  90  changes its solubility to a developer. So the exposed photoresist  78  can be easily washed out with the developer. 
         [0049]    Refer to  FIG. 24 . During this stage of the manufacturing process, part of the transparent conducting layer  76  and the ohmic contact layer  72 , which is not shielded by the non-exposed photoresist  78 , is removed by performing an etching process to form an opening  82 . The opening  82  is formed on top of the control electrode  661 . The ohmic contact layer  72  at both sides of the opening  82  forms a first ohmic contact layer  721  and a second ohmic contact layer  722 , respectively. 
         [0050]    Refer to  FIG. 25 . During this stage of the manufacturing process, a second passivation layer  84  is deposited on the remaining photoresist  78  and inside the opening  82  before the remaining photoresist  78  is removed. 
         [0051]    Refer to  FIG. 26 . During this stage of the manufacturing process, both of the photoresist  78  and the second passivation layer  84  deposited on the photoresist  78  are lifted off. The second passivation layer  84  inside the opening  82  is prevented from being lifted off because it does not adhere to the photoresist  78 . Thus, the second passivation layer  84  adheres to the inner surface of the opening  82  and to the top of the active layer  70  corresponding to the opening  82 , for isolating the active layer  70  from liquid crystal molecules. 
         [0052]    Refer to  FIG. 27 , which is a structure diagram of an LCD panel  90  according to the present invention. The LCD panel  90  comprises a glass substrate  601  and a glass substrate  602 . An LC layer  650  is injected on the glass substrate  601  on which the data line  62  and the switch unit  92  are arranged, and then the glass substrate  602  having a black matrix  642  and a color filter  644  covers the LC layer  650 . Another transparent electrode layer  640  covers the black matrix  642  and the color filter  644 . A common voltage is applied to the transparent electrode layer  640  functioning as a common voltage electrode layer. The transparent conducting layer  76  is divided into a first transparent conducting layer  76   a  and a second transparent conducting layer  76   b  by the opening  82 . The switch unit  92  can equivalently act as the TFT which controls data signals transmitted from the data line  62 . In other words, the control electrode  661  of the switch unit  92  can act as a gate of the TFT. Practically, the first transparent conducting layer  76   a  and the second transparent conducting layer  76   b  serve as a first electrode and a second electrode of the switch unit  92 , respectively. The first transparent conducting layer  76   a  and the second transparent conducting layer  76   b  can also serve as a source (a drain) of the TFT and a drain (a source) of the TFT, respectively. The active layer  70  serves as a channel between the drain of the switch unit  92  and the source of the switch unit  92 . The first transparent conducting layer  76   a,  functioning as a first electrode, is capable of outputting or inputting electrical signals. Correspondingly, the second transparent conducting layer  76   b,  functioning as a second electrode, is capable of outputting or inputting electrical signals. An object of the second passivation layer  84  adhering to the opening  82  is to separate the ohmic contact layer  72  from the active layer  70  functioning as the channel, so that the active layer  70  and the ohmic contact layer  72  are prevented from approaching the LC layer  650  directly and further from affecting the alignment of LC molecules. According to this embodiment, the second transparent conducting layer  76   b  serves as not only a second electrode of the TFT  92  but also, practically, a pixel electrode. Practically, an LC capacitor  96  is formed by an overlap of the pixel electrode and the transparent conducting layer  640 . Upon receiving a scanning voltage with the control electrode  661 , a data voltage transmitted from the data line  62  is transmitted to the second transparent conducting layer  76   b  (i.e., the pixel electrode) through the first transparent conducting layer  76   a  and the switch unit  92 . The alignment of the LC molecules of the LC layer  650  are adjusted according to a voltage difference between the data voltage applied on the second transparent conducting layer  76   b  and the common voltage applied on the transparent electrode layer  640 , which decides the transmittance of light beams. 
         [0053]    Refer to  FIG. 26 . The TFT  92  is formed on the glass substrate  601  according to the present embodiment. The TFT  92  comprises the first passivation layer  64  disposed on the glass substrate  601 , the gate  661  disposed on the first passivation layer  64 , the isolation layer  68  disposed on the gate  661 , the active layer  70  disposed on the isolation layer  68  and functioning as a channel of the TFT  92 , and the ohmic contact layer  72  disposed on the active layer  70  and having the opening  82 . The ohmic contact layer  72  at both sides of the opening  82  forms the first ohmic contact layer  721  and the second ohmic contact layer  722 , respectively. The transparent conducting layer  76  at both sides of the opening  82  forms the first transparent conducting layer  76   a  and the second transparent conducting layer  76   b , respectively. The first transparent conducting layer  76   a  is connected to the first ohmic contact layer  721  and serves as the first electrode for outputting or inputting electrical signals. The second transparent conducting layer  76   b  is connected to the second ohmic contact layer  722  and serves as the second electrode for outputting or inputting electrical signals. 
         [0054]    According to a preferred embodiment, the first ohmic contact layer  721  and the second ohmic contact layer  722  of the ohmic contact layer  72  is used for decreasing the resistance of the TFT  92 . According to another embodiment, the ohmic contact layer  72  is unnecessary during the manufacturing process, so the first ohmic contact layer  721  and the second ohmic contact layer  722  are not necessary for the LCD panel  90  and the TFT  92 . 
         [0055]    Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.