Abstract:
The present invention provides a touch integrated display device which reduces a thickness of a display device and can improve touch performance. The touch integrated display device according to one embodiment of the present invention can include: a TFT positioned on a lower substrate; a pixel electrode connected to the TFT; a common electrode facing the pixel electrode to form electric field; a liquid crystal layer positioned on the common electrode; an upper substrate facing the lower substrate which is positioned at both sides of the liquid crystal layer; a driving electrode which is positioned on one side of the upper substrate adjacent to the liquid crystal layer; and a sensing electrode which is positioned on the other side of the upper substrate and faces the driving electrode.

Description:
[0001]    This application claims the benefit of Korean Patent Application No. 10-2011-0017176 filed on Feb. 25, 2011 which is hereby incorporated by reference 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    This document relates to a touch display device, and more particularly to a touch integrated display device which can reduce thickness and improve touch performance. 
         [0004]    2. Description of the Related Art 
         [0005]    Various input devices, such as a keyboard, a mouse, a trackball, a joystick, a digitizer, and the like, are used for an interface between a user and home appliances or various information communication devices. However, in order to use the above input devices, the user should learn how to use the input devices and the quality thereof is not easily improved by causing inconvenience, such as a space necessary for installation thereof. Accordingly, a demand exists for input devices which have convenient and simple functions and can reduce malfunctions. In response, a touch panel has been proposed to enable a user to contact a screen using a hand or a pen to input information. 
         [0006]    The touch panel has simple functions, reduces the malfunctions, and enables the user to perform an input without using an additional input device. In addition, the touch panel can be applied to various display devices by enabling the user to perform rapid and easy operations through contents displayed on the screen. 
         [0007]    The touch panels can be classified into an add-on type, an on-cell type, and an in-cell type according to structures thereof. The add-on type is a type in which the touch panel is attached on an upper surface of a display device after the display device and the touch panel are separately manufactured. The on-cell type is a type in which elements included in the touch panel are directly formed on a surface of an upper glass substrate of the display device. The in-cell type is a type in which the elements constituting the touch panel are directly formed in the inside of the display device. 
         [0008]    However, the add-on type has a structure in which the completed touch panel is mounted on the display device and has the problems, such as increased thickness or reduced visibility due to low brightness of the display device. In addition, the on-cell type touch has a structure in which the touch panel is formed on an upper surface of the display device and can reduce the thickness in comparison with the add-on type but has the problems that the entire thickness is increased by a driving electrode layer, a sensing electrode layer, and an insulation layer for insulating the driving electrode layer and the sensing electrode layer and the increase of the entire thickness and the number of processes causes an increase in manufacturing costs. In addition, the in-cell type can reduce thickness of the display device by forming elements constituting the touch panel in the inside of the display device but has the problem that a driving electrode and a sensing electrode for composing the touch panel cause wirings and parasitic capacitance of the display device and the touch recognition performance is thereby lowered. 
         [0009]    Accordingly, a need for display devices rises to solve the problems. 
       SUMMARY 
       [0010]    An aspect of this document is to provide a touch integrated display device which can reduce thickness of a display device and improve touch performance. 
         [0011]    The touch integrated display device according to an aspect of the present invention can include a thin film transistor (TFT) positioned on a lower substrate, a pixel electrode connected to the TFT, a common electrode which faces the pixel electrode to form electric field, a liquid crystal layer positioned on the common electrode, an upper substrate facing the lower substrate which is positioned at both sides of the liquid crystal layer, a driving electrode which is positioned on one side of the upper substrate adjacent to the liquid crystal layer, and a sensing electrode which is positioned on the other side of the upper substrate and faces the driving electrode. 
         [0012]    The touch integrated display device according to an aspect of the present invention can include a TFT positioned on a lower substrate, a pixel electrode connected to the TFT, a liquid crystal layer positioned on the pixel electrode, an upper substrate facing the lower substrate which is positioned at both sides of the liquid crystal layer, a common electrode positioned on one side of the upper substrate adjacent to the liquid crystal layer, and a sensing electrode positioned on the other side of the upper substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0014]      FIG. 1  is a block diagram illustrating a touch integrated display device according to an embodiment of the present invention; 
           [0015]      FIG. 2A  is a plan view illustrating a lower substrate of a display device according to an embodiment of the present invention and  FIG. 2B  is a cross sectional view taken along line I-I′ of  FIG. 2A ; 
           [0016]      FIG. 3A  is a perspective view illustrating an upper substrate of a display device according to an embodiment of the present invention and  FIG. 3B  is a cross sectional view taken along line II-II′ of  FIG. 3A ; 
           [0017]      FIG. 4  is a view illustrating a touch integrated display device according to a first embodiment of the present invention; 
           [0018]      FIGS. 5A and 5B  are views illustrating a touch integrated display device according to a second embodiment of the present invention; 
           [0019]      FIG. 6  is a view illustrating a touch integrated display device according to a third embodiment of the present invention; 
           [0020]      FIG. 7  is a view illustrating a touch integrated display device according to a fourth embodiment of the present invention; 
           [0021]      FIG. 8  is a timing view of a touch integrated display device according to an embodiment of the present invention; 
           [0022]      FIG. 9  is a view illustrating a touch integrated display device according to a fifth embodiment of the present invention; and 
           [0023]      FIG. 10  is a timing view illustrating the touch integrated display device according to the fifth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    Exemplary embodiments of the present invention will be described in greater detail with reference to the accompanying drawings. 
         [0025]      FIG. 1  is a block diagram illustrating a touch integrated display device according to an embodiment of the present invention. 
         [0026]    Referring to  FIG. 1 , a touch integrated display device includes a liquid crystal display panel  100  including an upper substrate having color filters and a lower substrate having a TFT array, a backlight unit, a timing controller  101 , a data driver  102 , a gate driver  103 , a host controller  120 , a touch element  200 , a driving electrode driver  210 , a sensing electrode driver  230 , a touch controller  250 , and a touch recognition processor  270 . 
         [0027]    The liquid crystal panel  100  includes a liquid crystal layer and a spacer for maintaining a cell gap of the liquid crystal layer between the upper and lower substrates. 
         [0028]    The backlight unit is arranged under the liquid crystal display panel  100 . The backlight unit includes a plurality of light sources to uniformly irradiate light to the liquid crystal display panel  100 . The backlight unit can include a direct type backlight unit or an edge type backlight unit. The backlight unit can include at least one of light sources, such as a HCFL (Hot Cathode Fluorescent Lamp), a CCFL (Cold Cathode Fluorescent Lamp), an EEFL (External Electrode Fluorescent Lamp), and a LED (Light Emitting Diode). 
         [0029]    The data driver  102  samples and latches digital video data RGB under control of the timing controller  101 . The data driver  102  inverts a polarity of a data voltage by converting the digital video data RGB to positive/negative gamma compensation voltages GMA 1 -GMAn. The positive/negative gamma compensation voltages outputted from the data driver  102  are synchronized with a gate pulse outputted from the gate driver  103 . Source drive ICs (Integrated Circuits) of the data driver  102  can be respectively connected to data lines  104  of the liquid crystal display panel  100  in a Chip On Glass (COG) process or a Tape Automated Bonding (TAB) process. The source drive ICs are integrated in the timing controller  101  as one chip IC. 
         [0030]    The gate driver  103  sequentially outputs gate pulses (or scan pulses) in a display mode under the control of the timing controller  101  and shifts a swing voltage of the output gate pulses to a gate high voltage VGH and a gate low voltage VGL. The gate pulses outputted from the gate driver  103  are synchronized with the data voltage outputted from the data driver and are sequentially supplied to gate lines  105 . The gate high voltage VGH is greater than or equal to a threshold voltage of the TFT, and the gate low voltage VGL is lower than the threshold voltage of the TFT. Gate driving ICs of the gate driver  103  are connected to gate lines  105  of the lower substrate of the liquid crystal display panel  100  through a TAB process or can be directly formed on the lower substrate of the liquid crystal display panel  100  together with pixels through a Gate In Panel (GIP) process. 
         [0031]    The timing controller  101  generates a data timing control signal for controlling operation timing of the data driver  102  and the polarity of the data voltage by using a timing signal from the host controller  120  and a gate timing control signal for controlling operation timing of the gate driver  103 . 
         [0032]    The gate timing control signal includes a gate start pulse GSP, a gate shift clock GSC, a gate output enable signal GOE, and the like. The gate start pulse GSP is applied to a first gate driving IC for outputting a first gate pulse at each frame period from the gate driver  103  and controls the shift start timing of the gate driving IC. The gate shift clock GSC is a clock signal which is commonly inputted into the gate driving ICs of the gate driver  103  and shifts the gate start pulse GSP. The gate output enable signal GOE controls the output timing of the gate driving ICs of the gate driver  103 . 
         [0033]    The data timing control signal includes a source start pulse SSP, a source sampling clock SSC, a polarity control signal POL, and a source output enable signal SOE, and the like. The source start SSP is applied to a first source driving IC for first sampling the data in the data driver  102  and controls the data sampling start timing. The source sampling clock SSC is a clock signal for controlling the sampling timing of the data within the source driving ICs based on a rising or falling edge. The polarity control signal POL controls a polarity of the data voltages outputted from the source driving ICs. The source output enable signal SOE controls the output timing of the source driving ICs. When the digital video data RGB are inputted through a mini Low Voltage Differential Signaling (LVDS) interface to the data driver  102 , the source start pulse SSP and the source sampling clock SSC can be omitted. 
         [0034]    The host controller  120  transmits digital video data RGB of an input image and timing signals Vsync, Hsync, DE, MCLK necessary for driving the display through interfaces of the LVDS interface, a Transition Minimized Differential Signaling (TMDS) interface, and the like to the timing controller  101 . In a display device according to first to fourth embodiments to be described below, the host controller  120  receives touch coordinates from the touch controller and performs an application corresponding to the touch coordinates. In a display device according to a fifth embodiment, the host controller  120  supplies a control signal for controlling a power supply unit (not shown) to supply a common voltage Vcom to a common electrode in a display driving period for displaying an image on a screen of the display device or to supply a touch driving voltage Vtsp to the common electrode in a touch driving period for recognizing a touch. 
         [0035]    The touch element  200  includes a plurality of driving electrodes  201  which are arranged in parallel to each other in a first direction (for example, a X-direction), a plurality of sensing electrodes  203  which are arranged in parallel to each other in a second direction (for example, a Y-direction) crossing the first direction, and an upper substrate (not shown) which is positioned between the driving electrodes  201  and the sensing electrodes  203  and prevents an electrical contact between the sensing electrodes  203  and the driving electrodes  201 . 
         [0036]    The driving electrode driver  210  scans the driving electrodes  201  by sequentially supplying the pulse voltages Vtsp generated from the power supply unit (not shown) to the driving electrodes  201  of the touch element  200 . The sensing electrode driver  230  senses the pulse voltage Vtsp and transmits the sensed pulse voltage to the touch recognition processor  270  after finishing the scanning operation for the driving electrodes  201 . 
         [0037]    The touch recognition processor  270  is connected to the sensing electrodes  203  of the touch element  200 , differentially amplifies voltages of initial capacitance and touch capacitance of conductive patterns of the touch element  200 , and converts the results to digital data. The touch recognition processor  270  determines a touch position based on a difference between the initial capacitance and the touch capacitance by using a touch recognition algorithm and outputs touch data for indicating the touch position to the touch controller  250 . 
         [0038]    The touch controller  250  generates a scanning control signal to a driving electrode driver  210  for driving the touch element  200 . The touch controller  250  receives the scanning control signal from the timing controller  101  and applies the scanning control signal to the driving electrode driver  210 . 
         [0039]      FIG. 2A  is a plan view illustrating a lower substrate of a display device according to an embodiment of the present invention, and  FIG. 2B  is a cross sectional view taken line I-I′ of  FIG. 2A . 
         [0040]    Referring to  FIG. 2A , a gate line  310  is extended in one direction on a lower substrate  300 , and a data line  320  is positioned across the gate line  310  and defines a sub-pixel P. A common line  330  is arranged in parallel to the gate line  310  and intersects with the data line  320 . The sub-pixel P is defined at the intersection among the gate line  310 , the data line  320 , and the common line  330 . 
         [0041]    A TFT Tr is positioned at the sub-pixel P and includes a gate electrode G connected to the gate line  310 , a gate insulating layer (not shown), a semiconductor layer  317 , a source electrode S connected electrically to the data line  320 , and a drain electrode D separated from the source electrode S. 
         [0042]    A plate type common electrode  335  is positioned at the sub-pixel P, and a bar type pixel electrode  340   a  having a plurality of openings  340   b  is positioned and corresponds to the common electrode  335  in the sub-pixel P. The common electrode  335  is electrically connected through a first contact hole CH 1  to the common line  330  to receive a voltage. The pixel electrode  340   a  is electrically connected through a second contact hole CH 2  to the drain electrode D. 
         [0043]    Referring to  FIG. 2B , the gate line (not shown) and the gate electrode G are positioned in one direction on the lower substrate  300  and the common electrode  330  which is arranged in parallel to and is separated from the gate line (not shown) is positioned on the same plane. 
         [0044]    A gate insulating layer  314  is positioned on the gate electrode G and the common line  330  and insulates the gate electrode G and the common line  330  from each other. The semiconductor layer  317  is positioned on an area corresponding to the gate electrode G on the gate insulating layer  314 . The source electrode S and the drain electrode D are respectively positioned at both ends of the semiconductor layer  317 . As a consequence, a TFT Tr including the gate electrode G, the semiconductor layer  317 , the source electrode S, and the drain electrode D is formed. 
         [0045]    A first protective layer  325  including the TFT is positioned on the lower substrate  300 . The common electrode  335  and the common line  330  are electrically connected to each other through the first contact hole CH 1  which penetrates the gate insulating layer  314  and the first protective layer  325  to expose the common line  330 . The pixel electrode  340   a  and the drain electrode D are electrically connected to each other through a second contact hole CH 2  which penetrates the first protective layer  325  to expose the drain electrode D. A second protective layer  345  is positioned between the pixel electrode  340   a  and the common electrode  335  to insulate the pixel electrode  340   a  and the common electrode  335  from each other. 
         [0046]      FIG. 3A  is a perspective view illustrating an upper substrate according to an embodiment of the present invention, and  FIG. 3B  is a cross sectional view taken line II-II′ of  FIG. 3A . 
         [0047]    Referring to  FIGS. 3A and 3B , a display device according to an embodiment of the present invention includes black matrixes  365  and color filters  360  which are positioned on a lower part of an upper substrate  350 , an overcoat layer  370  positioned on the color filters  360 , driving electrodes  380  positioned on the overcoat layer  370 , sensing electrodes  390  positioned on the upper substrate  350 , and an upper polarizer  400  positioned on the sensing electrodes  390 . 
         [0048]    Specifically, the driving electrodes  380  and the sensing electrodes  390  are positioned at both sides of the upper substrate  350  to form the touch element. 
         [0049]    The driving electrodes  380  are formed along a first direction on the lower surface of the upper substrate  350 . For example, the driving electrodes  380  can be formed to have a regular pattern, such as a diamond pattern, on the lower surface of the upper substrate  350 . As described above, the driving electrodes  380  can include a plurality of X patterns which are formed to connect the driving electrodes  380  positioned in one column having the same X-coordinates with each other. The driving electrodes  380  are not limited to having the diamond shape and can have various shapes, such as combinations of repeated polygons including shapes of a square, a rectangle, a diamond, a pyramid, an inverse pyramid, a sawtooth, and the like. 
         [0050]    The sensing electrodes  390  are arranged along a second direction on the upper substrate  350  alternately arranged with the driving electrode  380  while not overlapping the driving electrodes  380 . For example, the sensing electrodes  390  and the driving electrodes  380  are formed to have the same diamond pattern. The sensing electrodes  390  can include a plurality of Y patterns which are formed to connect the sensing electrodes  390  positioned in one row having the same Y-coordinates with each other. 
         [0051]    The sensing electrodes and the driving electrodes  390  and  380  are formed of a transparent material through which light emitted from the display panel passes. The sensing electrodes and the driving electrodes  390  and  380  are formed of a transparent electrode material, such as Indium Tin Oxide (ITO). 
         [0052]    Each of the sensing and driving electrodes  390  and  380  can have a thickness that can be set to be within a range in which a transmittance of light emitted from the display panel is secured and a relatively low surface resistance is obtained. A thickness of the sensing electrodes and the driving electrodes  390  and  380  can be set to be optimized in consideration of the transmittance and the surface resistance. 
         [0053]    For example, the sensing electrodes and the driving electrodes  390  and  380  can include an ITO pattern having a thickness of 100-300 Å. The embodiments of the present invention are not limited thereto and the thickness of the sensing and driving electrodes  390  and  380  can be changed in consideration of the transmittance and/or the surface resistance. 
         [0054]    As described in  FIG. 3B , while components of a touch element as described above are assembled, when a finger of a person or an object contacts an upper part of the upper substrate  350 , capacitance of the sensing electrodes and the driving electrodes  390  and  380  is changed at the contact position. The change in the capacitance is converted to an electrical signal by a touch recognition processor so that the contact position is detected and a display device is operated. 
         [0055]    Various touch integrated display devices according to embodiments of the present invention are described in detail. 
         [0056]      FIG. 4  is a view illustrating a touch integrated display device according to a first embodiment of the present invention. 
         [0057]    Referring to  FIG. 4 , in the touch integrated display device according to the first embodiment of the present invention, a gate electrode G and a common line  530  are positioned on a lower substrate  500 , and a gate insulating layer  515  is positioned to insulate the gate electrode G from the common line  530 . A semiconductor layer  517  is positioned on the gate insulating layer  515 , and a source electrode S and a drain electrode D are respectively connected to two ends of the semiconductor layer  517 . A first protective layer  525  is positioned on the lower substrate  500  including the source electrode S and the drain electrode D. A common electrode  535  is connected to the common line  530  through a first contact hole CH 1  which penetrates the first protective layer  525  and the gate insulating layer  515 . A second protective layer  545  is positioned on the common electrode  535 . A pixel electrode  540   a  is electrically connected to the drain electrode D through a second contact hole CH 2  which penetrates the second protective layer  545  and the first protective layer  525 . The pixel electrode  540   a  includes a plurality of bar type openings  640   b.    
         [0058]    A liquid crystal layer  549  is positioned on the lower substrate  500 , and an upper substrate  550  is positioned on the liquid crystal layer  549 . The upper substrate  550  includes a black matrix  565  and a color filter  560  positioned at a lower part of the upper substrate  550 , an overcoat layer  570  positioned on the color filter  560 , and driving electrodes  580  positioned on the overcoat layer  570 . Sensing electrodes  590  are positioned on the upper substrate  550 , an upper polarizer  595   a  is positioned on the sensing electrodes  590 , and a lower polarizer  595   b  is positioned at a lower part of the lower substrate. The sensing electrodes  590  can be obtained by dividing an anti-electrostatic transparent conductive layer included in a conventional display device. 
         [0059]    The touch integrated display device includes a touch element which includes the driving electrodes  580  positioned at the lower surface of the upper substrate  550  and the sensing electrodes  590  positioned at the upper surface of the upper substrate  550 . The pixel electrode  540   a  and the common electrode  535  are formed at the lower substrate to drive the display panel. 
         [0060]    The liquid crystal layer  549  according to the following embodiments can be driven by an In-Plane Switching (IPS) method or by a Fringe Field Switching (FFS) method. In the following embodiments, the same elements as described in connection with  FIG. 4  may be denoted by the same or substantially the same reference numerals. 
         [0061]      FIGS. 5A and 5B  are views illustrating a touch integrated display device according to a second embodiment of the present invention. 
         [0062]    Referring to  FIGS. 5A and 5B , in the touch integrated display device according to the second embodiment of the present invention, the driving electrodes  580  described in connection with  FIGS. 4A and 4B  are not formed, and black matrixes  565  instead plays a role as the driving electrodes  580 . 
         [0063]    More specifically, referring to  FIG. 5B , the black matrixes  565  are arranged in parallel to each other in an X-direction on the upper substrate  550  and R, G, and B, and color filters  560  are respectively positioned at sub-pixel regions. The black matrixes  565  are divided along a direction perpendicular to a longitudinal direction of the sub-pixel P, that is, a y-direction. For example, the black matrixes  565  are divided in a direction intersecting the sensing electrodes and include a metal material so that the black matrixes  565  play a role as the driving electrodes. 
         [0064]    As such, in the touch integrated display device according to the second embodiment of the present invention, the black matrixes  565  are divided and include a metal material so that the black matrixes  565  can play a role as the driving electrodes of the touch element. 
         [0065]      FIG. 6  is a view illustrating a touch integrated display device according to a third embodiment of the present invention, and  FIG. 7  is a view illustrating a touch integrated display device according to a fourth embodiment of the present invention. 
         [0066]    Referring to  FIG. 6 , the touch integrated display device according to the third embodiment of the present invention includes the upper polarizer  595   a  attached on the upper surface of the upper substrate  550 , an electrode film  610  positioned on the sensing electrodes  590 , an adhesive  620  positioned on the electrode film  610 , and a reinforcing glass plate  630  attached to the electrode film  610  through the adhesive  620 . 
         [0067]    According to an embodiment, the sensing electrodes  590  are formed on the electrode film  610 . The electrode film  610  is attached on the upper substrate to which the upper polarizer  595   a  is attached. The adhesive  620  is formed on the upper substrate  550  to which the electrode film  610  is attached, and the reinforcing glass plate  630  is attached on the adhesive  620 . 
         [0068]    Referring to  FIG. 7 , in the touch integrated display device according to the fourth embodiment, the sensing electrodes  590  are formed on the electrode film  610 , and the electrode film  610  is attached on the reinforcing glass plate  610 . The adhesive  620  is formed on the upper substrate  550  to which the upper polarizer  595   a  is formed and the reinforcing glass plate  630  is attached on the adhesive  620 . 
         [0069]    Next, operations of the touch integrated display devices according to the first to fourth embodiments are described. Hereinafter, 60 Hz time division driving is described as an example. 
         [0070]      FIG. 8  is a timing view of a touch integrated display device according to an embodiment of the present invention. 
         [0071]    Referring to  FIG. 8 , a touch integrated display device according to an embodiment of the present invention is driven by a time division drive method. In the time division drive method, as described in  FIG. 8 , one period includes a display drive period and a touch drive period. Touch driving is in an off state during the display period, and display driving is in an off state during the touch period to minimize signal interference between the touch driving and display driving. For example, one period is 16.7 ms in the 60 Hz time division driving and is divided into a display period (about 10 ms) and a touch period (about 6.7 ms). 
         [0072]    In the display period, the host controller  120 , for example, supplies the common voltage Vcom through the gate line  103  to the common electrode. The data driver  102  is synchronized with a gate pulse Gate outputted from the gate driver  103  and supplies a pixel voltage Data corresponding to the digital video data through the data line  104  to the pixel electrode. As the electric field is formed in the liquid crystal layer by the common electrode Vcom and the pixel voltage Data applied to the pixel electrode and the common electrode, respectively, a state of the liquid crystal is changed thus performing a display operation. The touch recognition processor  270  connected to the sensing electrodes  203  of the touch elements measures and stores the voltage value of the initial capacitance of each of the driving electrodes  201  and the sensing electrodes  203 . 
         [0073]    Next, in the touch drive period, the host controller  120 , for example, supplies the touch driving voltage Vtsp to the driving electrodes  201  of the touch element. The touch recognition processor  270  connected to the sensing electrodes  203  differentially amplifies the stored voltage value of the initial capacitance of each of the driving electrodes  201  and the sensing electrodes  203  and the voltage Vd of the capacitance measured in the touch drive period and converts the result to the digital data. A touch recognition processor  107  determines the touch position based on the difference between the initial capacitance and the touch capacitance by using a touch recognition algorithm and outputs touch coordinates data for indicating the touch position. 
         [0074]    The touch integrated display device is driven by the time division drive method in which the touch driving is in the off state and the touch drive voltage Vtsp is not supplied during the display period and the display driving is in the off state and the common voltage Vcom is not supplied during the touch drive period. 
         [0075]    As described above, the touch integrated display devices according to the first to fourth embodiments of the present invention reduce thickness, improve visibility, and prevent generation of the parasitic capacitance by forming a touch element in the touch integrated display devices. 
         [0076]      FIG. 9  is a view illustrating a touch integrated display device according to a fifth embodiment of the present invention. 
         [0077]      FIG. 10  is a timing view illustrating the touch integrated display device according to the fifth embodiment of the present invention. 
         [0078]    Referring to  FIG. 9 , in the touch integrated display device according to the fifth embodiment of the present invention, a gate line (not shown) and a gate electrode G are arranged in one direction on a lower substrate  700 . A gate insulating layer  715  is positioned on the gate electrode G for insulation of the gate electrode G, and a semiconductor layer  717  is positioned on a region corresponding to the gate electrode G on the gate insulating layer  715 . A source electrode S and a drain electrode D are positioned at two ends of the semiconductor layer  717 . Accordingly, a TFT Tr including the gate electrode G, the semiconductor layer  317 , the source electrode S, and the drain electrode D is formed. 
         [0079]    A protective layer  725  is positioned on the lower substrate  700  including the TFT Tr. A pixel electrode  740  and the drain electrode D are electrically connected through a third contact hole CH 3  which penetrates the protective layer  725  and exposes the drain electrode D. A liquid crystal layer  749  is positioned on the lower substrate  700 . The liquid crystal layer  749  of the present embodiment can be driven by a driving method, such as a Twisted Nematic (TN) method or a Vertical Alignment (VA) method. 
         [0080]    An upper substrate  750  is positioned on the liquid crystal layer  749 . The upper substrate  750  includes black matrixes  765  and a color filter  760  positioned at a lower part of the upper substrate  750 , an overcoat layer  770  positioned on the color filter  760 , and a common electrode  780  positioned on the overcoat layer  770 . Sensing electrodes  790  are positioned on the upper substrate  750 , an upper polarizer  795   a  is positioned on the sensing electrodes  790 , and a lower polarizer  795   b  is positioned at a lower part of the lower substrate. 
         [0081]    In a touch integrated display device according to an embodiment, the touch element is formed by forming the common electrode  780  at a lower surface of the upper substrate  750  and forming the sensing electrodes  790  on an upper surface of the upper substrate  750 . In the lower substrate  700 , the display panel is driven by the pixel electrode  740  and the common electrode  780  of the pixel electrode  740 . The common electrode  780  formed at the upper substrate  750  plays a role as the driving electrodes of the touch element together with the sensing electrodes  790 . The common electrode  780  drives the liquid crystal layer  749  together with pixel electrode  740  formed at the lower substrate  700 . The common electrode  780  intersects the sensing electrodes  790  and is divided into a plurality of electrodes to play a role as the driving electrodes of the touch element. 
         [0082]    Referring to  FIG. 10 , the touch integrated display device according to the fifth embodiment of the present invention is driven by the time division drive method. One period in the time division driving, as illustrated in  FIG. 10 , includes a display period and a touch period. The touch driving is in an off state during a display period, and the display driving is an off state during a touch period. For example, one period is 16.7 ms in the 60 Hz time division driving and is divided into a display period (about 10 ms) and a touch period (about 6.7 ms). 
         [0083]    In the display period, the host controller, for example, supplies the common voltage Vcom through the gate line to the common electrode  780  formed with the driving electrodes of the touch element. The data driver is synchronized with a gate pulse Gate outputted from the gate driver and supplies the pixel voltage Data corresponding to the digital video data through the data line to the pixel electrode  740 . As the electric field is formed in the liquid crystal layer by the common electrode Vcom and the pixel voltage Data applied to the pixel electrode  740  and the common electrode  780 , respectively, a state of the liquid crystal is changed thus performing a display operation. The touch recognition processor connected to the sensing electrodes  790  of the touch elements measures and stores the voltage value of the initial capacitance of each of the common electrodes  780  and the sensing electrodes  790 . 
         [0084]    Next, in the touch drive period, the host controller, for example, supplies the touch driving voltage Vtsp to the common electrodes  780 . The touch recognition processor connected to the sensing electrodes  790  differentially amplifies the stored voltage value of the initial capacitance of each of the common electrodes  780  and the sensing electrodes  790  and the voltage Vd of the capacitance measured in the touch drive period and converts the result to the digital data. The touch recognition processor determines the touch position based on the difference between the initial capacitance and the touch capacitance by using the touch recognition algorithm and outputs the touch coordinates data for indicating the touch position. 
         [0085]    In the touch integrated display device, the touch driving is in the off state and the common voltage Vcom is supplied and the touch driving voltage Vtsp is not supplied during the display period. The display driving is in the off state and the common voltage Vcom is not supplied to the common electrode and the touch driving voltage Vtsp is supplied to the common electrode during the touch drive period. 
         [0086]    The touch integrated display device according to the fifth embodiment of the present invention may reduce thickness, improve visibility, and prevent generation of the parasitic capacitance by sharing the common electrode for driving the liquid crystal display panel and the common electrode for driving the touch element. 
         [0087]    The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the foregoing embodiments is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Moreover, unless the term “means” is explicitly recited in a limitation of the claims, such limitation is not intended to be interpreted under 35 USC 112(6).