Abstract:
A display device includes a plurality of gate lines and a plurality of data lines crossing each other on a first substrate, to define a pixel; a first thin film transistor in a portion where the gate lines and the data lines cross each other; a plurality of position detection lines on the first substrate, the position detection lines spaced a constant distance from the data lines and crossing the gate lines; a second thin film transistor for detecting a position, in a portion on the first substrate where the gate lines and the position detection lines cross each other; a protrusion pattern protruding from a second substrate and corresponding to a drain electrode of the second thin film transistor; and a transparent conductive layer on the protrusion pattern, electrically connected to the drain electrode when touching.

Description:
[0001]    The present application claims the benefit of Korean Patent Application No. 10-2008-0042668 filed on May 8, 2008, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a display device and a method of manufacturing the same, which can simplify structure thereof. 
         [0004]    2. Discussion of the Related Art 
         [0005]    Personal computers, portable transmitting devices, and other personal data-processing devices process texts and graphics with various input devices including keyboards, mice and digitizers. 
         [0006]    Such input devices, as interfaces corresponding to the purpose of PCs, continue to evolve for simple and easy operation. 
         [0007]    Today, beyond meeting requirements relating to a common function of an input device, delicate technologies become more important, which includes reliability, services with new functions, durability, a design allowing for materials and substances, and manufacturing and producing methods. 
         [0008]    Specifically, touch panels are well known as an input device that is simple to operate, and easy to input data in mobile situations, and makes it possible to input characters without an additional input device. 
         [0009]    Such a touch panel commonly includes an upper substrate having upper electrodes and a lower substrate having lower electrodes, in which the upper and lower substrates are spaced apart from each other. When touching, with an input member such as a pen or a finger, a certain point of the upper substrate including the upper electrodes, the upper electrode in the upper substrate corresponding to the touched point is electrically connected to the lower electrode disposed in the lower substrate, then a voltage value changed depending on a resistance value or capacitance value corresponding to the touched point is determined, and then position coordinates are detected at a position detection driver according to the change of potential difference. 
         [0010]    Such a touch panel is disposed on a top of a display device such that a user directly touches e.g., an icon displayed on the display device with his/her finger or stuff and desired content is selected for the user. 
         [0011]    However, since the touch panel is disposed on the top of the display device, a product including the touch panel becomes thick and large. Also, position detection drivers should be provided for supplying a driving voltage for an x-axis and a y-axis, which results in complicated structure. 
       SUMMARY OF THE INVENTION 
       [0012]    Accordingly, the present invention is directed to a liquid crystal display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
         [0013]    An advantage of the present invention is to provide a display device and a method of manufacturing the same, which can simplify structure thereof. 
         [0014]    Additional features and advantages of the invention will be set forth in part in the description which follows and in part will become apparent from the description may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0015]    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a display device includes a plurality of gate lines and a plurality of data lines crossing each other on a first substrate, to define a pixel; a first thin film transistor in a portion where the gate lines and the data lines cross each other; a plurality of position detection lines on the first substrate, the position detection lines spaced a constant distance from the data lines and crossing the gate lines; a second thin film transistor for detecting a position, in a portion on the first substrate where the gate lines and the position detection lines cross each other; a protrusion pattern protruding from a second substrate and corresponding to a drain electrode of the second thin film transistor; and a transparent conductive layer on the protrusion pattern, electrically connected to the drain electrode when touching. 
         [0016]    In another aspect of the present invention, a method of manufacturing a display device, the method includes forming a thin film transistor substrate comprising: forming a first thin film transistor in a portion where gate lines and data lines cross each other; and forming a second thin film transistor in a portion where and the gate lines and position detection lines spaced a constant distance from the data lines cross each other; and forming a color filter substrate comprising a protrusion pattern in a portion corresponding to a drain electrode of the second thin film transistor. 
         [0017]    It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiment(s) and together with the description serve to explain the principle of the invention. 
           [0019]    In the drawings: 
           [0020]      FIG. 1  is a schematic view illustrating a liquid crystal display device according to an embodiment. 
           [0021]      FIG. 2  is a plan view illustrating a pixel taken from a region A of  FIG. 1 . 
           [0022]      FIG. 3  is a cross-sectional view illustrating a liquid crystal display device taken along lines I-I′ and II-II′ of  FIG. 2 . 
           [0023]      FIGS. 4A to 4E  are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to an embodiment. 
           [0024]      FIGS. 5A to 5D  are cross-sectional views illustrating a method of manufacturing a color filter substrate according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0025]    Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
         [0026]      FIG. 1  is a schematic view illustrating a liquid crystal display device according to an embodiment.  FIG. 2  is a plan view illustrating a pixel taken from a region A of  FIG. 1 .  FIG. 3  is a cross-sectional view illustrating a liquid crystal display device taken along lines I-I′ and II-II′ of  FIG. 2 . 
         [0027]    Referring to  FIGS. 1 to 3 , the liquid crystal display device includes a liquid crystal display panel  110 , a data driver  120 , a gate driver  130 , and a timing controller  150 . The liquid crystal display panel  110  includes a color filter substrate and a thin film transistor substrate that are attached to each other. The data driver  120  supplies data signals to data lines DL 1  through DLm of the liquid crystal display panel  110 . The gate driver  130  supplies scan signals to gate lines GL 1  through GLn of the liquid crystal display panel  110 . The timing controller  150  controls the data driver  120  and the gate driver  130 . 
         [0028]    The gate lines GL 1  through GLn cross the data lines DL 1  through DLm at the thin film transistor substrate of the liquid crystal display panel  110 , to form cross portions where first thin film transistors TFT 1  for driving liquid crystal cells Clc are disposed. 
         [0029]    The thin film transistor substrate of the liquid crystal display panel  110  further includes position detection lines PL 1  through PLm- 1  and a position detection driver  170 . The position detection lines PL 1  through PLm- 1  are parallel with the data lines DL 1  through DLm. The position detection driver  170  is adapted to supply a constant position detection voltage to the position detection lines PL 1  through PLm- 1 . 
         [0030]    The first thin film transistors TFT 1  are disposed at the liquid crystal cells Clc of the thin film transistor substrate, respectively. The first thin film transistors TFT 1  serve as a switch device. First gate electrodes  141  of the first thin film transistors TFT 1  are connected to the gate lines GL 1  through GLn. First source electrodes  145  are connected to the data lines DL 1  through DLm. A first drain electrode  146  is connected to a pixel electrode  149  of the liquid crystal cell Clc and one electrode of a first storage capacitor Cst 1 . A common voltage Vcom is supplied to a common electrode of the liquid crystal cell Clc. When the first thin film transistor TFT 1  is turned on, the first storage capacitors Cst 1  are charged with data voltages supplied from the data lines DL 1  through DLm to maintain the liquid crystal cell Clc at a constant voltage. 
         [0031]    Second thin film transistors TFT 2  are disposed in portions of the thin film transistor substrate where the gate lines GL 1  through GLn cross the position detection lines PL 1  through PLm- 1 . Second gate electrodes  171  of the second thin film transistors TFT 2  are connected to the gate lines GL 1  through GLn. Second source electrodes  176  are connected to the position detection lines PL 1  through PLm- 1 . A second drain electrode  175  is connected to a sensing electrode  179 . 
         [0032]    Second storage capacitors Cst 2  for detecting a position are provided to the position detection lines PL 1  through PLm- 1 . The second storage capacitor Cst 2  is adjacent to the second source electrode  176  of the second thin film transistor TFT 2  and charged with the constant position detection voltage supplied from the position detection driver  170 . 
         [0033]    The color filter substrate of the liquid crystal display panel  110  includes a protrusion pattern  166  and a support pattern  165 . The protrusion pattern  166  is disposed in a corresponding region to the second drain electrode  175  of the second thin film transistor TFT 2 . The support pattern  165  is adapted to keep a constant gap between the color filter substrate and the thin film transistor substrate. A transparent conductive layer  169  is disposed on the protrusion pattern  166  and the support pattern  165 . 
         [0034]    When scan pulses are sequentially supplied to the gate lines GL 1  through GLn, the first thin film transistors TFT 1  are turned on, and channels are formed between the source electrodes  145  and the first drain electrodes  146 , so that voltages of the data lines DL 1  through DLm are supplied to the pixel electrodes  149  of the liquid crystal cells Clc. At this point, molecular arrangement of the liquid crystal cells Clc are changed according to electric fields between the pixel electrodes  149  and the common electrodes, to modulate incident light. 
         [0035]    In addition, when the scan pulses are sequentially supplied to the gate lines GL 1  through GLn, the second thin film transistors TFT 2  are turned on, and channels are formed between the second source electrodes  176  and the second drain electrodes  175 , so that the second storage capacitors Cst 2  are charged with the position detection voltages from the position detection lines PL 1  through PLm- 1 . 
         [0036]    The data driver  120  supplies a data signal to the data lines DL 1  through DLm in response to a data drive control signal DDC supplied from the timing controller  150 . Also, the data driver  120  samples and latches an image data “Data R, G, B” input from the timing controller  150 , then converts the latched data into an analogue data voltage by a gamma reference voltage, and then supplies the converted data to the data lines DL 1  through DLm. The gamma reference voltage is supplied from a gamma reference voltage generation unit (not shown) through a gamma reference voltage selection unit (not shown). The analogue data voltage is used to express a gray scale in the liquid crystal cell Clc of the liquid crystal display panel  110 . 
         [0037]    The data drive control signal supplied from the timing controller  150  includes SSP, SSC, SOE, and POL. 
         [0038]    The gate driver  130  sequentially generates the scan pulses using a gate drive control signal GDC supplied from the timing controller  150  and supplies the generated scan pulses to the gate lines GL 1  through GLn. 
         [0039]    The GDC supplied from the timing controller  150  includes GSP, GSC, and GOE. 
         [0040]    The position detection driver  170  generates the position detection voltages, and when the second thin film transistors TFT 2  are turned on by the scan signals supplied to the gate lines GL 1  through GLn, the position detection driver  170  supplies the position detection voltages to the position detection lines PL 1  through PLm- 1  and the second storage capacitors Cst 2  are charged with the position detection voltages. At this point, when the liquid crystal display panel  110  is touched with a finger or a pen, the protrusion pattern  166  disposed on the color filter substrate in a corresponding pixel contacts the second drain electrode  175  of the second thin film transistor TFT 2 , so that potential of the position detection voltage stored in the second storage capacitor Cst 2  is changed. More particularly, since the transparent conductive layer  169  is disposed on the protrusion pattern  166 , and a driving signal is supplied to the transparent conductive layer  169 , when the transparent conductive layer  169  contacts the second drain electrode  175 , the potential of the position detection voltage stored in the adjacent second storage capacitor Cst 2  is changed. 
         [0041]    The potential change of the position detection voltage is used to determine position coordinates in an x-axis direction (a perpendicular direction to the position detection lines). Position coordinates in a y-axis direction (a perpendicular direction to the gate lines) is determined through feedback of a gate control signal supplied to turn on the second thin film transistor TFT 2 . 
         [0042]    The liquid crystal display device includes the second thin film transistor TFT 2  in the portions where the gate lines GL 1  through GLn cross the position detection lines PL 1  through PLm- 1 , and the protrusion pattern  166  at the color filter substrate corresponding to the second drain electrode  175  of the second thin film transistor TFT 2 . Thus, x-axis position coordinates are detected by bringing the transparent conductive layer  169  disposed on the protrusion pattern  166  in contact with the second drain electrode  175  through touching, and y-axis position coordinates are detected with the gate control signal. This makes it possible to realize a display device integrated with a multi-touch function. 
         [0043]    At this point, a driving signal, supplied to the transparent conductive layer  169  of the color filter substrate, is refreshed by respective frames. The driving signal may be the common voltage Vcom supplied to the liquid crystal display panel  110 . 
         [0044]    Thus, according to this embodiment, the second thin film transistor TFT 2  is disposed in the cross portions of the gate lines GL 1  through GLn and the position detection lines PL 1  through PLm- 1 , and the protrusion pattern  166  is provided to the color filter substrate corresponding to the second drain electrode  175  of the second thin film transistor TFT 2 . This makes it to realize a display device having both a touch function and slim design. 
         [0045]    Also, according to this embodiment, the multi-touch is possible, and y-axis position coordinates are detected with the gate control signal, thus only the position detection driver  170  for detecting x-axis position coordinates is provided, thereby achieving simple structure. 
         [0046]    The structure of the thin film transistor substrate and the color filter substrate in the liquid crystal display device will now be described in more detail with reference to  FIG. 3 . 
         [0047]    The thin film transistor substrate includes the first and second gate electrodes  141  and  171  on a first mother substrate  140 , and gate dielectrics  142  and  172  are formed on the first mother substrate  140  with the first and second gate electrodes  141  and  171 . 
         [0048]    First and second active patterns  143  and  173  are disposed on the gate dielectrics  142  and  172 , and first and second ohmic contact patterns  144  and  174  are disposed on the first and second active patterns  143  and  173 . 
         [0049]    The first source electrode  145  and the first drain electrode  146  are disposed on the first active pattern  143  and the first ohmic contact pattern  144 . The second source electrode  176  and the second drain electrode  175  are disposed on the second active pattern  173  and the second ohmic contact pattern  174 . 
         [0050]    A passivation layer  147  is disposed on the gate dielectrics  142  and  172  with the first and second source electrodes  145  and  176  and the first and second drain electrodes  146  and  175 . A first planarization layer  148  is disposed on the passivation layer  147 . 
         [0051]    Contact holes are disposed in the first planarization layer  148  to expose the first and second drain electrodes  146  and  175 . 
         [0052]    The first drain electrode  146  is electrically connected to the pixel electrode  149 , and the second drain electrode  175  contacts the sensing electrode  179 . That is, the pixel electrode  149  and the sensing electrode  179  are disposed on the first planarization layer  148 . 
         [0053]    The color filter substrate includes light-blocking patterns  161  on a second mother substrate  160  facing the thin film transistor substrate such that the light-blocking patterns  161  correspond to the gate lines GL 1  through GLn of  FIG. 1 , the data lines DL 1  through DLm of  FIG. 1 , and the first and second thin film transistor TFT 1  and TFT 2 . 
         [0054]    A color filter  162  is disposed on the second mother substrate  160  with the light-blocking patterns  161 . The color filter  162  may be any one of a red color filter, a green color filter, and a blue color filter. 
         [0055]    The support pattern  165  and the protrusion pattern  166  are disposed on the light-blocking patterns  161 . An end of the support pattern  165  contacts the thin film transistor substrate, but an end of the protrusion pattern  166  does not contact the thin film transistor substrate. The support pattern  165  is longer than the protrusion pattern  166 . That is, only an external pressure (an arrow of  FIG. 3 ) brings the protrusion pattern  166  in contact with the thin film transistor substrate. 
         [0056]    A second planarization layer  163  is disposed on the light-blocking patterns  161  and the color filter  162 , except for the support pattern  165  and the protrusion pattern  166 . The transparent conductive layer  169  is disposed on the protrusion pattern  166  and the support pattern  165  with the second planarization layer  163 . 
         [0057]      FIGS. 4A to 4E  are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to an embodiment. 
         [0058]    Referring to  FIG. 4A , a conductive material is formed on a first mother substrate  140  through a depositing method such as a sputtering process, and first and second gate electrodes  141  and  171  are formed through a photolithography process and an etching process with a mask. Although not shown, the first and second gate electrodes  141  and  171  and gate lines are simultaneously formed. 
         [0059]    The first and second gate electrodes  141  and  171  contain any one of metals including aluminum (Al), aluminum alloy (AlNd), tungsten (W), copper (Cu), molybdenum (Mo), chrome (Cr) and molybdenum-tungsten (MoW). 
         [0060]    Gate dielectrics  142  and  172  are deposited on the first mother substrate  140  with the first and second gate electrodes  141  and  171 . 
         [0061]    The gate dielectrics  142  and  172  may be one of a silicon nitride (SiNx) layer, a silicon oxide (SiO 2 ) layer, and a stacked layer of the silicon nitride (SiNx) and silicon oxide (SiO 2 ) layers, which are formed through any one of a chemical vapor deposition method and a sputtering method. 
         [0062]    Referring to  FIGS. 4B and 4C , an amorphous silicon layer, an impurity-doped amorphous silicon layer, and a conductive layer are sequentially stacked on the gate dielectrics  142  and  172 , and then a photolithography process and an etching process with a mask are performed such that a first active pattern  143 , a first ohmic contact pattern  144 , a first source electrode  145 , and a first drain electrode  146  are formed in a region corresponding to the first gate electrode  141 , and simultaneously, a second active pattern  173 , a second ohmic contact pattern  174 , a second source electrode  176 , and a second drain electrode  175  are formed in a region corresponding to the second gate electrode  171 . 
         [0063]    The source electrode  145  and the first drain electrode  146  are separated by a first contact hole  180   a , and the second source electrode  176  and the second drain electrode  175  are separated by a second contact hole  180   b.    
         [0064]    Referring to  FIG. 4D , a passivation layer  147  is formed on an entire surface of the first mother substrate  140  with first and second thin film transistor TFT 1  and TFT 2 . 
         [0065]    A first planarization layer  148  is formed on the passivation layer  147 , and third and fourth contact holes  180   c  and  180   d  are formed in the first planarization layer  148  through a photolithography process and an etching process to expose the first and second drain electrodes  146  and  175  to the outside. 
         [0066]    Referring to  FIG. 4E , any one of transparent conductive metal groups including indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) is deposited on an entire surface of the first planarization layer  148  with the third and fourth contact holes  180   c  and  180   d , then a photolithography process and an etching process using a mask to form a pixel electrode  149  and a sensing electrode  179 . 
         [0067]      FIGS. 5A to 5D  are cross-sectional views illustrating a method of manufacturing a color filter substrate according to an embodiment. 
         [0068]    Referring to  FIG. 5A , light-blocking patterns  161  are formed on a second mother substrate  160  of the color filter substrate facing a thin film transistor substrate. The light-blocking patterns  161  contain a carbonate based organic material or a metal thin film including chrome and are formed through a photolithograph process and an etching process. 
         [0069]    A high-molecular organic material  164  is applied on the second mother substrate  160  with the light-blocking patterns  161 . 
         [0070]    Referring to  FIG. 5B , a photolithography process and an etching process with a diffraction mask is performed on the high-molecular organic material  164  to form a support pattern  165  and a protrusion pattern  166 . 
         [0071]    An exposure amount of the support pattern  165  are greater than that of the protrusion pattern  166  by controlling the exposure amounts according to a diffraction intensity of the diffraction mask such that the support pattern  165  has a larger thickness than the protrusion pattern  166 . 
         [0072]    Referring to  FIG. 5C , on the basis of a boundary of the light-blocking patterns  161 , a color filter  162  is formed on the second mother substrate  160  corresponding to a pixel. 
         [0073]    The color filter  162  may be formed as any one of red, green and blue color filters, and be out of the support pattern  165  and the protrusion pattern  166 . 
         [0074]    A second planarization layer  163  is formed on the second mother substrate  160  with the color filter  162  and the light-blocking patterns  161 . 
         [0075]    The second planarization layer  163  protects the color filter  162  and planarizes the second mother substrate  160  and has a less thickness than those of the support pattern  165  and the protrusion pattern  166 . 
         [0076]    Referring to  FIG. 5D , any one of a transparent conductive metal groups including indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) is deposited on the second planarization layer  163  with the support pattern  165  and the protrusion pattern  166 , to from a transparent conductive layer  169 . 
         [0077]    As described above, the liquid crystal display device according to the embodiment includes the thin film transistor for detecting positions in the portions where the gate lines and the position detection lines of the thin film transistor substrate cross each other, and the protrusion pattern is provided to the color filter substrate corresponding to the drain electrode of the thin film transistor. Thus, when being pressed by an external touch, the transparent conductive layer disposed on the protrusion pattern contacts the drain electrode to detect the position detection voltage change of the storage capacitor disposed at the position detection line adjacent to the thin film transistor, so that x-axis position coordinates are detected, and y-axis position coordinates are detected with the feedback of the gate control signal. This makes it possible to realize a display device integrated with the touch function. 
         [0078]    Thus, according to the embodiments, a display device having both a touch function and slim design can be realized. 
         [0079]    Also, the multi-touch is possible, and y-axis position coordinates are detected with the gate control signal, thus only the position detection driver detecting x-axis position coordinates is provided, thereby achieving simple structure. 
         [0080]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.