Abstract:
A display device is disclosed, which includes: a substrate; a first conductive layer disposed on the substrate and including a gate with a gate edge parallel to a first direction; a semiconductor layer disposed on the first conductive layer; and a second conductive layer disposed on the semiconductor layer and including a drain and a data line extending along the first direction, the second conductive layer electrically connecting to the semiconductor layer, the drain including a drain edge parallel to the first direction, the gate edge located between the data line and the drain edge, and a projection of the drain on the substrate located in a projection of the semiconductor layer on the substrate. Herein, a maximum width of the semiconductor layer overlapping the gate edge along the first direction is smaller than maximum widths thereof overlapping the gate and the drain edge along the first direction.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefits of the Taiwan Patent Application Serial Number 103117752, filed on May 21, 2014, the subject matter of which is incorporated herein by reference. 
         [0002]    This application is a continuation (CA) of U.S. Patent application for “Display device”, U.S. application Ser. No. 14/669,557 filed Mar. 26, 2015, and the subject matter of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a display device, and especially to a display device able to reduce the resistance and avoid the electrical interference between the first conductive layer and the second conductive layer. 
         [0005]    2. Description of Related Art 
         [0006]    Since the technology of display devices developed quickly, the display devices with thin thickness, low weight, and compact size are the major products on the market. In fact, the old cathode-ray tube displays are greatly replaced by the liquid crystal displays (LCD) in major areas around the world. Nowadays, the liquid crystal displays (LCD) is widely applied in many electrical devices such as mobile phones, notebook computers, cameras, video recorders, music players, global positioning system devices, and televisions. Moreover, since the demand of the devices with human-friendly operation, and simplification is strong, the display device with touch panel will be widely used in people&#39;s daily life. 
         [0007]    The thin film transistor liquid crystal display (TFT-LCD) uses the thin film transistor technology to improve the image quality. In short, the TFT-LCD is made of two glass substrate and a liquid crystal layer located there between. The top glass substrate is a color filter substrate, and the bottom substrate is a transistor substrate. When a current is applied to the transistor, an electrical field generates and further rotates the liquid crystal molecules to change the polarity of the incident light. Through the assistance of foreign polarizers, the darkness or the brightness of pixels on the display can be controlled and adjusted. Hence, by controlling the brightness of plural pixels, the image of a frame can be displayed. Generally, many types of TFT-LCD are widely used now. The common types are twisted nematic (TN) type, super twisted nematic (STN) type, vertical alignment (VA) type, in-plane switching (IPS) type, and fringe field switching (FFS) type. 
         [0008]    Even though the technologies of display device become much more matured now, the consumers&#39; demand for high image quality is still strong. Hence, a display device with improved display quality is still needed to be made to meet the demand for the market. 
       SUMMARY OF THE INVENTION 
       [0009]    An object of the present invention is to provide a display device able to reduce resistance, and prevent electrical disturbance between the first conductive layer and the second conductive layer. 
         [0010]    To achieve the above object, the present invention provides a display device, comprising: a substrate comprising a display region and a non-display region surrounding the display region; a first conductive layer disposed on the substrate; a semiconductor layer disposed on the substrate and having a first portion and a second portion, wherein the first conductive layer is located between the first portion and the substrate, and the second portion doesn&#39;t overlap the first conductive layer; and a second conductive layer disposed on a top surface of the semiconductor layer, and combined with the first conductor layer and the semiconductor layer to form plural thin film transistors located in the display region, wherein the second conductive layer comprises plural data lines, each data line has a first side and a second side, the first side and the second side are arranged with an interval, and part of the first side is near to a channel of one of thin film transistors corresponding to the first side; wherein the second side of each data line is spaced from the neighboring side of the semiconductor layer in a first distance on the first portion of the semiconductor layer, the second side of each data line is spaced from the neighboring side of the semiconductor layer in a second distance on the second portion of the semiconductor layer, and the first distance is greater than the second distance. 
         [0011]    The present invention provides another display device, comprising: a substrate comprising a display region and a non-display region surrounding the display region; a first conductive layer disposed on the substrate; a semiconductor layer disposed on the substrate and partially covering the first conductive layer, and there is a spacing between a first side of the semiconductor layer and a second side of the second conductive layer from a top view, wherein the first side of the semiconductor layer is adjacent to the second side of the second conductive layer; wherein the spacing in the display region is a first distance, the spacing in the non-display region is a second distance, and the first distance is smaller than the second distance. 
         [0012]    As a result, in the display device of the present invention, because the first distance which is defined by the first portion of the semiconductor layer and the substrate having a first conductive layer there between to the second side of the neighboring data line is greater than the second distance which is defined by the second portion of the semiconductor layer and the substrate without a first conductive layer there between to the second side of the neighboring data line. That can avoid electrical disturbance between the first conductive layer and the second conductive layer, and avoid effective penetration percentage in the region without conductive layers. Besides, the fifth distance defined by one side of the second conductive layer in the non-display region and the neighboring side of the semiconductor layer located thereunder is greater than the sixth distance defined by one side of the corresponding second conductive layer in the display region and the neighboring side of the semiconductor layer located thereunder, so that it can reduce resistance effectively and avoid increasing parasite capacitance to affect efficiency of the liquid crystal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  shows the schematic diagram of the display device according to a preferable embodiment of the present invention. 
           [0014]      FIG. 2A  shows the schematic diagram of the pixel structure in display region according to a preferable embodiment of the present invention. 
           [0015]      FIG. 2B  shows the cross-sectional view of the section line “a” in  FIGS. 2A . 
           [0016]      FIG. 2C  shows the cross-sectional view of the section line “b” in  FIGS. 2A . 
           [0017]      FIG. 2D  shows the cross-sectional view of the section line “c” in  FIGS. 2A . 
           [0018]      FIG. 3  shows the schematic diagram of the pixel structure in display region according to another preferable embodiment of the present invention. 
           [0019]      FIG. 4  shows the schematic diagram of the pixel structure in display region according to further another preferable embodiment of the present invention. 
           [0020]      FIG. 5A  shows the schematic diagram of the pixel structure in non-display region according to a preferable embodiment of the present invention. 
           [0021]      FIG. 5B  shows the cross-sectional view of the section line “d” in  FIGS. 5A . 
           [0022]      FIG. 5C  shows the cross-sectional view of the section line “e” in  FIGS. 5C . 
           [0023]      FIG. 6  shows the cross-sectional view of the pixel structure according to another preferable embodiment of the present invention. 
           [0024]      FIG. 7  shows the cross-sectional view of the pixel structure according to further another preferable embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    Hereinafter, exemplary embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms. The following embodiments are described in order to enable those of ordinary skill in the art to embody and practice the present invention, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible. 
       Embodiment 1 
       [0026]    Please refer to  FIG. 1 . A display device  100  including a non-display region  51  and a display region  52  is provided. As shown in  FIG. 2 , the pixel structure in the display region  52  includes a substrate having a non-display region  51  and a display region  52  surrounding the display region  51 ; a first conductive layer  1  disposed on the substrate; an insulation layer locating and covering the first conductive layer  1 ; a semiconductor layer  2  locating on the insulation layer and having a first portion  21  and a second portion  22 , wherein the first conductive layer  1  locates between the first portion  21  and the substrate, and the second portion  22  doesn&#39;t overlap the first conductive layer  1 ; and a second conductive layer  3  locating on the top surface of the semiconductor layer  2 , and further including data lines  31  and electrodes  32  in the display region  52 . Moreover, each data line  31  has a first side  311  and a second side  312 , and the first side  311  is separated from the second side  312  through the data line  31 . The first conductive layer  1 , the semiconductor layer  2 , and the second conductive layer  3  are combined together to form plural thin film transistors  4 . One part of the first side  311  is near to the channel  7  of at least one thin film transistor  4 . The second side  312  is not near to the channel  7  of the thin film transistor  4 . The shape profile of the second side  312  is the same as that of side profile  23  of the semiconductor layer  2 . 
         [0027]    Please refer to the enlarged view diagram of the region in  FIG. 2A . The second side  312  of the data line  31  is spaced from the neighboring side of the first portion  21  in a first distance. The second side  312  of the data line  31  is spaced from the neighboring side of the second portion  22  in a second distance there between. Moreover, the first distance is greater than the second distance. The cross-sectional view of the section line “a” is shown in  FIG. 2B . The structure of the pixel subsequently includes a substrate  5 , a first conductive layer  1 , an insulation layer  6 , a semiconductor layer (i.e. the first portion  21  in this cross-sectional view), and a second conductive layer  3 . The second side  312  of a data line  31  of the second conductive layer  3  contacts the semiconductor  2  with a first contact border  33 . Then a first distance D 1  is defined by the interval width between the first contact border  33  and the first portion  21  of the semiconductor layer. In addition, the cross-sectional view of the section line “b” is shown in  FIG. 2C . The structure of the pixel subsequently includes a substrate  5 , an insulation layer  6 , a semiconductor (i.e. the second portion  22  in this cross-sectional view), and a second conductive layer  3 . Likewise, a second distance D 2  is defined by the interval width between the first contact border  33  and the second portion  22  of the semiconductor layer. The first distance D 1  is greater than the second distance D 2 . 
         [0028]    Referring to  FIG. 2D ,  FIG. 2D  is a cross-sectional view according to the sectional line “c” in  FIG. 2A , and is the details of the structure of the thin film transistor  4  is shown here. The pixel structure subsequently includes a substrate  5 , a first conductive layer  1 (including a gate), an insulation layer  6 , a semiconductor layer  2  (including a channel  7 ), and a second conductive layer  3  (including a source, a drain made of a data line  31 , and electrode  32 , respectively). The first side  311  of the data line is close to one side of the channel  7 , and the second side  312  locates on the other side opposite to the first side  311 . 
         [0029]    In the present embodiment, the first distance D 1  is in a range of 0.7 μm to 1.5 μm, preferably 0.8 μm to 1.1 μm. The second distance D 2  is in a range of 0.3 μm to 1.0 μm, preferably 0.5 μm to 0.7 μm. The ratio of first distance D 1  to the second distance D 2  preferably is 1.3 to 1.7, but is not limited thereto. If the first distance D 1  and the second distance D 2  is greater than the range illustrated above, then the achievement of the neighboring semiconductor  2  (i.e. the semiconductor neighboring to the pixel) is not possible to be achieved in the manufacturing process. In addition, when the ratio of the first distance D 1  to the second distance D 2  is in the range described above, it can shield the electromagnetic interference and reduce the resistance of the data line. 
         [0030]    However, the pixel structure in the display region  52  is not limited thereto, and it can be any common structure known by the people skilled in the art. In  FIG. 3 , and  FIG. 4 , the structure characters are the same as those of  FIG. 2A . The second side  312  of the data line  31  is spaced from one side of the first portion  21  with an interval of first distance D 1 , and the second side  312  of the data line  31  is spaced from one side of the second portion  22  with another interval of second distance D 2 . The first distance D 1  is greater than the second distance D 2 . 
         [0031]    In addition, the pixel structure in the non-display region is shown in  FIG. 5A . The second conductive layer  3  includes plural circuit lines  33  in the non-display region  51 . One side  34  of the circuit lines  33  and the neighboring side of the first portion  21  of the semiconductor layer  2  is separated by an interval of third distance D 3 , the side  34  of circuit lines  33  and the neighboring side of the second portion  22  of the semiconductor layer  2  is separated by an interval of fourth distance D 4 , and the third distance is greater than the fourth distance. The cross-sectional view of the section line “d” is shown in  FIG. 5B . The structure of the pixel subsequently includes a substrate  5 , a first conductive layer  1 , an insulation layer  6 , a semiconductor  2 , and a second conductive layer  3 . The side  34  of a data line  3  of the second conductive layer  3  contacts the semiconductor  2  with a second contact border  35 . The second contact border  35  and the neighboring side of the first portion  21  of the semiconductor layer are separated by an interval of third distance D 3 . Furthermore, the cross-sectional view of the section line “e” is shown in  FIG. 5C . The structure of the pixel subsequently includes a substrate  5 , an insulation layer  6 , a semiconductor  2 , and a second conductive layer  3 . The second contact border  35  and the neighboring side of the second portion  22  of the semiconductor layer are separated by an interval of fourth distance D 4 . In the present embodiment, the third distance can be 1 μm to 2 μm, and preferably 1.4 μm to 1.7 μm. 
         [0032]    In other words, by way of controlling the etching step or using a gray tone mask, the condition that the first distance D 1  is greater than the second distance D 2  and the third distance D 3  is greater than the fourth distance D 4  can be achieved. It is known that when a first conductive layer locates between the semiconductor layer  2  and the substrate  5 , a parasite capacitance generates and the parasite capacitance further interferes with the transmission of electrical signals through the second conductive layer  3 . However, the parasite capacitance can be reduced by shrinking the second conductive layer  3  on the semiconductor layer  2 . Moreover, when the semiconductor layer  2  doesn&#39;t overlap the first conductive layer  1 , the light scattering from the passing of the light from the backlight module can be improved, and the contrast deterioration caused by the scattering from the interface can be avoided by shortening the width of the second distance D 2 . 
         [0033]    Furthermore, the third distance D 3  defined by the second contact border  35  in the non-display region  51  and the first portion  21  of the semiconductor layer is greater than the second distance D 2  defined by the second side  312  of the data line  31  in the display region  52  and second portion  22  of the semiconductor, or the third distance D 3  is greater than first distance D 1  defined by the second side  312  of the data line  31  and the first portion  21 . 
         [0034]    To reduce the resistance of the circuit line  33  of the second conductive layer  3  in the non-display region  51 , the distance (i.e. the third distance) between the circuit line  33  and the semiconductor layer  2  is increased. Then the resistance can be reduced and the efficient width of the conductive lines can be increased. Hence, in the present embodiment, the first distance D 1  in the display region  52  is set to be greater than the second distance D 2 , and the third distance in the non-display region is set to be greater than the first distance D 1  in the display region  52  at the same time to improve the display quality of the display device. 
       Embodiment 2 
       [0035]    Another display device (similar to the display device shown in  FIG. 1 , including a display region  51  and a non-display  52  surrounding the display region  51 ) is also provided in the present embodiment. Part of the pixel structure cross-sectional view (shown in  FIG. 6 ) subsequently includes a substrate  5  including a display region  51  and a non-display  52 , a first conductive layer  1  located on the substrate  5 , an insulation layer  6  located on and covering the first conductive layer  1 , a semiconductor layer  2  located on the substrate  5  and partially covering the first conductive layer  1 , and a second conductive layer  3  formed on the top surface of the semiconductor layer  2 . The sides  36 ,  36 ′ of the second conductive layer contact with the semiconductor layers through contact borders  37 ,  37 ′. The contact border  37  in the non-display region  51  and the neighboring side of the semiconductor layer  2  are separated by an interval of a fifth distance D 5 , the contact border  37 ′ in the display region  52  and the neighboring side of the semiconductor layer  2  are separated by an interval of a sixth distance D 6 , and the fifth distance D 5  is greater than the sixth distance D 6 . 
         [0036]    In the present embodiment, the second conductive layer  3  may include plural data lines in the display region  52 . Each data line has a first side and a second side, and the first side is separated from the second side through the data line. Moreover, part of the first side in the display region  52  is near to the channel of a thin film transistor, and the second side is not near to the channel of the thin film transistor. The shape of the second side is the same as that of the side profile of the semiconductor layer. The sixth distance D 6  is the distance between the contact border  37 ′ of the second side and the neighboring side of the semiconductor layer. 
         [0037]    In the present embodiment, the fifth distance D 5  may be in a range of 0.7 μm to 2.0 μm, and the sixth distance D 6  may be in a range of 0.3 μm to 1.5 μm. The ratio of the fifth distance D 5  to the sixth distance D 6  is preferred to be 1.2 to 1.6, but the present invention is not limited thereto. 
         [0038]    Another part of cross-sectional view of the pixel structure as shown in  FIG. 7 , a semiconductor layer may have a first portion  21  and a second portion  22 , wherein the first conductive layer  1  locates between the first portion  21  and the substrate  5 , and first conductive layer  1  doesn&#39;t locate between the second portion  22  and the substrate  5 ; the contact border  37 ′ and the neighboring side of the first portion  21  are separated by an interval of a seventh distance D 7 , the contact border  37 ′ and the neighboring side of the second portion  22  are separated by an interval of a eighth distance D 8 , and the seventh distance D 7  is greater than the eighth distance D 8 . In the present embodiment, the seventh distance D 7  may be in a range of 1 μm to 2 μm. 
         [0039]    Therefore, in order to reduce resistance, the distance between the second conductive layer and the neighboring side of the semiconductor layer in non-display region should be greater than that between the second conductive layer and the neighboring side of the semiconductor layer in display region. Besides, if the distance (i.e. sixth distance D 6 ) in display region between the semiconductor layer and the data line thereon increases, parasite capacitance between the semiconductor layer and the first conductive layer thereunder may also increase, so that efficiency of the liquid crystal is getting worse. To avoid affecting efficiency of the liquid crystal, the seventh distance D 7  in non-display region is set to greater than the sixth distance D 6  and the eighth distance D 8  in display region preferably. 
         [0040]    The display device of the present invention may be completely fabricated by the people skilled in the art, so we will not go further on this here. The first conductive layer  1 , the second conductive layer  2  may use the common conducting material in the art such as metal, alloy, metallic oxide, metallic nitrogen-oxide, or other common electrode material in the art; and preferably is metal. The substrate may use the common substrate material such as glass substrate, plastic substrate, silicon substrate, ceramic substrate. The insulation layer may use the common gate insulating material such as silicon nitride (SiN); and the semiconductor layer may use the common semiconducting material, including amorphous silicon, poly silicon, or organic material such as P13, DH4T, and pentacene. 
         [0041]    In the embodiment illustrated above, it will be understood by those skilled in the art that some components in display device has been omitted, for example the pixel structure of the aforementioned embodiment can combine with a colorful optical filter substrate, liquid crystal layer, backlight module to form a liquid crystal display device. The display device of the present invention can be a variety of flat panel display, for example, it can be a liquid crystal display (LCD), or an organic light emitting diode display (OLED); practical application such as car displays, electromagnetic isolation glass, cell phones, solar cells, portable LCD video games, home appliances LCD panel, instrument displays, organic light-emitting diode displays, LCD monitors, notebook computers, LCD TVs, plasma monitors, color filters electrodes or the combination thereof. 
         [0042]    Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.