Patent Publication Number: US-2009237365-A1

Title: Display panel and method for manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0025937 filed in the Korean Intellectual Property Office on Mar. 20, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a display panel in which input sensitivity is improved for efficiently detecting the input coordinate values of a touch by a user. 
     2. Description of the Related Art 
     A touch screen panel is an information input means which inputs information when a user touches a screen. The touch screen panel is installed on an image display surface of a display device such as a liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) device, and an electro luminescence (ELD) device. 
     The touch screen panel is greatly classified into a capacitive touch screen panel and a resistive touch screen panel. The capacitive touch screen panel has one transparent conductive film or glass for storing electrical charges. When the touch screen panel is touched by, e.g., a stylus, a small amount of charge is drawn to a contact point between the stylus and the transparent conductive film. The amount of charge detected at the contact point is converted into coordinate values. In the resistive touch screen panel, if a user touches a screen in a state that a voltage is applied to two opposite conductive layers, the two conductive layers contact, and a change in voltage or electrical current occurs at the contact point. The change in voltage or electrical current is detected and converted into coordinate values. 
     In case of the capacitive touch screen panel, electricity should be supplied to a stylus. For this reason, the resistive touch screen panel of an analog input method, which is constructed integrally with an LCD panel, is usually used. The resistive touch screen panel may be formed inside an LCD panel in order to prevent brightness of the LCD panel from being degraded. 
     In an LCD panel with an integrated touch screen panel, first sensing lines and second sensing lines are formed in a matrix form in a thin film transistor (TFT) array substrate so that a first coordinate value which represents a horizontal contact point and a second coordinate value which represents a vertical contact point can be detected. Also, a touch spacer which contacts the first and second touch sensing lines is formed in a color filter array substrate. In case of a conventional LCD panel with an integrated touch screen panel, there is a problem in that detecting error is frequently caused because the touch sensitivity is low when the touch spacer is contacting the thin film transistor array substrate. And nowadays the touch input motion become more complicated, as techniques such as dragging a point, drawing a line, writing characters and paint some portions of the screen are implemented. 
     SUMMARY 
     Aspects of the invention provide a display panel in which input sensitivity is improved by making a surface of a sensing electrode concave. Various touch motions can be detected easily with this improved display panel structure. In an exemplary embodiment, the present invention provides a display panel, including: a first substrate including a sensing electrode, a second substrate including a touch spacer, a column spacer supporting the first and second substrate and a liquid crystal layer interposing between the first and second substrate, wherein the sensing electrode facing the touch spacer having a concave surface. 
     The touch spacer has a conductive material and further a transparent conductive material. 
     The display panel further includes a first alignment layer on the sensing electrode, a second alignment layer on the touch spacer and the second alignment layer on the touch spacer becomes thinner as the alignment layer is closer to the second substrate. 
     In another exemplary embodiment, the present invention provides a first substrate including a sensing electrode, a second substrate including a touch spacer, a column spacer supporting the first and second substrate, a liquid crystal layer interposed between the first and second substrate and the sensing electrode facing the touch spacer having a concave surface and a side wall of the sensing electrode slopes. 
     In another exemplary embodiment, the present invention provides a first substrate including a sensing electrode and a thin film transistor for driving a pixel, a second substrate including a black matrix layer, a touch spacer facing the sensing electrode, a column spacer supporting the first and second substrate and a liquid crystal layer interposed between the first and second substrate wherein the sensing electrode has a concave surface. 
     The touch spacer has a conductive material, further a transparent conductive material. 
     The display panel further includes a first alignment layer on the sensing electrode and a second alignment layer on the touch spacer, wherein the second alignment layer on the touch spacer becomes thinner as the alignment layer is closer to the second substrate. 
     The thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, an active layer on the gate insulating layer, an ohmic contact layer on the active layer, a source and drain electrode on the ohmic contact layer, a passivation film having a contact hole and a pixel electrode contacting the drain electrode through the contact hole, wherein the pixel electrode and the sensing electrode is substantially the same material at the same layer. 
     The passivation film has a concave surface under the sensing electrode. 
     The display panel further includes a first sensing line and a second sensing line electrically connected to the sensing electrode and at least one of first sensing line, the second sensing line, the gate insulating layer or passivation film makes the concave surface for the sensing electrode. 
     In another exemplary embodiment, the present invention provides a method for manufacturing a display panel including: forming a touch spacer on a upper substrate, forming a sensing electrode on a lower substrate, forming a column spacer supporting the upper and lower substrate, and interposing a liquid crystal layer between the first and second substrate, wherein the sensing electrode facing the touch spacer has a concave surface. 
     The touch spacer has a conductive material or a transparent conductive material. 
     The method for manufacturing a display panel further includes forming a first alignment layer on the sensing electrode and forming a second alignment layer on the touch spacer, wherein the second alignment layer on the touch spacer becomes thinner as the alignment layer is closer to the second substrate. 
     A side wall of the sensing electrode slopes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view schematically illustrating a sensing portion in a display panel according to an exemplary embodiment of the present invention; 
         FIG. 2  is a plan view of a display panel according to the first exemplary embodiment of the present invention; 
         FIG. 3  is a cross-sectional view taken along line I-I′ of  FIG. 2 ; 
         FIG. 4  is a cross-sectional view taken along line II-II′ of  FIG. 2 ; 
         FIG. 5  is a cross-sectional view illustrating a sensing portion of a display panel according to the second exemplary embodiment of the present invention; 
         FIG. 6  is a cross-sectional view illustrating a sensing portion of a display panel according to the third exemplary embodiment of the present invention; 
         FIG. 7  is a cross-sectional view illustrating a sensing portion of a display panel according to the fourth exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. 
     It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     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. For example, if the device in the figures is turned over, elements described as “below” or “lower” other elements or features would then be oriented “above” or “upper” relative to the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a cross-sectional view schematically illustrating a sensing portion in a display panel according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , the display panel according to an exemplary embodiment of the present invention includes an upper substrate  11 , a lower substrate  12 , a column spacer  13  and a liquid crystal layer  17  interposed between the upper substrate  11  and the lower substrate  12 . On the upper substrate, a touch spacer  14  is located. The touch spacer  14  may have a conductive material, for example, conductive polymer. The touch spacer  14  may be made of several layers such as an ITO (Indium Tin Oxide) layer on an organic spacer or an IZO (Indium Zinc Oxide) layer on an inorganic protrusion, etc. Though  FIG. 1  does not show any connected electrical circuit or wiring, the conductive touch spacer  14  is electrically connected to the circuit. 
     A sensing electrode  16  is formed on the lower substrate  12 . The sensing electrode may be a transparent conductive material. The sensing electrode  16  faces the touch spacer  14  on the upper substrate  11 . The sensing electrode  16  has a concave upper surface on a well structure  15 . The well structure  15  may be formed by a photolithography method using an inorganic or organic material. Though  FIG. 1  does not show any connected electrical circuit, the conductive sensing electrode  16  is electrically connected to the circuit. 
     When a touch action is inputted to the upper substrate  11 , the touch spacer  14  contacts the sensing electrode  16  on the lower substrates. As the sensing electrode  16  has a concave surface, the touch spacer  14  can contact the sensing electrode  16  in a 3-dimensional direction. When the user simply touches the upper substrate  11  to activate a push the button in the display, the touch spacer  14  moves in the z-direction and the touch spacer  14  meets the sensing electrode  16  on the bottom portion of the sensing electrode  16   b . But when the user drags some point or draws a picture, the touch event includes an x, y, or z direction or movement, and the touch spacer  14  may move downward in the x, y and z direction. The sensing electrode  16  having a concave surface makes more contact opportunities for the touch spacer. Because the sensing electrode has a concave surface, the touch spacer has more contact points in the x and y direction. The side wall of the sensing electrode  16   s  may be contacted by the touch spacer  14 . 
     Even if there is no dragging or drawing touch event, for example there is only a z-direction touch inputted into the device, the concave sensing electrode  16  has more contact points like the side wall of the sensing electrode, so the sensitivity of the device may be increased. 
     When the touch event is inputted, the current or voltage of the sensing electrode  16  changes and the change is communicated to the driving circuit. 
     Here, the upper substrate  11  and the lower substrate  12  may be made of a transparent material such as glass, PET film, or quartz, etc. The column spacer  13  may be formed from organic material by coating and photolithography. The column spacer  13  may be formed by a ball spacer using a scattering method. The touch spacer  14  has a smaller height than that of the column spacer  13 . The well structure  15  may be formed from a SiNx, SiOx or other inorganic material by chemical vapor deposition, sputtering deposition, or evaporation method, etc. For making a well structure as illustrated in  FIG. 1  photolithography may be conducted using a slit mask or half tone mask. Although in the  FIG. 1  the sensing electrode layer  16  has a concave surface by the lower well structure  15 , the sensing electrode  16  may have a well structure by itself having concave surface using a photolithography or metal imprinting, etc. 
     EMBODIMENT 1 
       FIG. 2  is a plan view of a display panel according to the first exemplary embodiment of the present invention. 
     The display panel includes a pixel arrayed in a matrix in  FIG. 2 . The pixel is driven by the thin film transistor (hereinafter TFT) which is electrically connected to a gate line  210  and a data line  240 . A pixel electrode  260  is electrically connected to the TFT A gate electrode  211  which is connected to the gate line  210  has a gate turn on and turn off signal through the gate line  210 . A source electrode  241  which is connected to the data line  240  transmits the data signal to a drain electrode  243  which is apart from the source electrode  241 . Between the gate electrode  211  and the source electrode  241 , there is a semiconductor  211 . The pixel electrode  260  is electrically connected to the drain electrode  243  through the contact hole  251 . 
     The display panel has a sensing portion  400  for detecting the touch by the user. A first sensing line  215  which is parallel with the gate line  210  and a second sensing line  245  which is parallel with the data line  245  are located near the pixel electrode  260 . A sensing electrode includes a first sensing electrode  270  and a second sensing electrode  280  which are electrically connected to the sensing line  215 ,  245 , respectively. The touch spacer is located opposite the sensing electrodes  270  and  280  as illustrated in  FIG. 1 . When the user touches the display panel, the touch spacer may contact the sensing electrodes  270  and  280 . The changes of the voltage or current of sensing electrode  270 ,  280  by the touch are transmitted through the first and the second sensing line  215  and  245 . 
       FIG. 3  is a cross-sectional view taken along line I-I′ of  FIG. 2 ; 
     The display panel includes a first substrate  100  and a second substrate  200  with a liquid crystal layer  300  interposed therebetween. 
     The first substrate  100  includes a black matrix  110  for preventing a light leakage, a color filter layer  120  for realizing a color image, an overcoat layer  130  for mitigating a step difference between the black matrix  110  and the color filter layer  120 , and a common electrode  150  for applying a common voltage to the liquid crystal layer, which are sequentially formed on an upper substrate  101 . The first substrate  100  may further include an alignment layer (not drawn) on the common electrode  150 . 
     The upper substrate  101  may be made of a transparent insulating material such as plastic so that it can be smoothly pushed when a user touches its surface. The upper substrate  101  may be made of a transparent insulating material such as glass. 
     The black matrix  110  preventing the light leakage from a back light (not drawn) is formed to overlap a TFT. The black matrix  110  is made of an opaque organic material or an opaque metal. 
     The color filter layer  120  includes red (R), green (G) and blue (B) color filters to create various colors. The red (R), green (G) and blue (B) color filters create red, green and blue colors by absorbing and transmitting light of a certain wavelength through red, green and blue pigments contained therein, respectively. At this time, various colors can be realized by an additive color mixture of the red (R), green (G) and blue (B) light which pass through the red (R), green (G) and blue (B) color filters. 
     The overcoat layer  130  is made of a transparent organic material for step coverage and insulation of the common electrode  150 . The overcoat layer  130  also serves to protect the color filter layer  120  and the black matrix  110 . 
     The common electrode  150  is formed on the overcoat layer  130 . The common electrode  150  is made of a transparent conductive metal such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode  150  forms an electrical field for driving the liquid crystal layer together with a pixel electrode  260  by applying a common voltage to the liquid crystal layer as the pixel electrode  260  applies a pixel voltage to the liquid crystal layer. 
     The second substrate  200  includes the TFT and the pixel electrode  260  which are formed on a lower substrate  201 . 
     The gate electrode  211  is formed on the lower substrate  201 . The gate electrode  211  may have a single-layer structure or a multi-layer structure made of molybdenum (Mo), niobium (Nb), copper (Cu), aluminum (Al), chromium (Cr), silver (Ag), tungsten (W), titanium (Ti) or alloys thereof. The source and drain electrode  241 ,  243  may have a single-layer structure or a multi-layer structure made of Mo, Nb, Cu, Al, Cr, Ag, titanium (Ti), or other alloys. 
     The TFT performs a switching operation in response to a gate signal transmitted from the gate line  210  (in  FIG. 2 ) so that a pixel voltage signal of the data line  240  may be charged and maintained in the pixel electrode  260 . To this end, the TFT includes the gate electrode  211  extending from the gate line  210  (in  FIG. 2 ), a source electrode  241  extending from the data line  240 , and a drain electrode  243  apart from the source electrode  241  and electrically connected to the pixel electrode  260 . 
     The TFT further includes a gate insulating layer  220  and a semiconductor layer  230 . The gate insulating layer  220  is formed over the surface of the lower substrate  201  to cover the gate electrode  211 . The semiconductor layer  230  is formed on a portion of the gate insulating layer  220  above the gate electrode  211  to form a channel between the source electrode  241  and the drain electrode  243 . 
     The semiconductor layer  230  includes an active layer  231  and an ohmic contact layer  233 . The active layer  231  is formed to have a channel between the source and drain electrodes  241  and  243 , overlapping the gate electrode  211 . The ohmic contact layer  233  is formed on the active layer  231  for ohmic contact with the source and drain electrodes  241  and  243 . 
     The second substrate  200  further includes a passivation film  250  formed over the surface of the lower substrate  201 . The passivation film  250  is made of an inorganic insulating material, such as silicon nitride (SiNx) or silicon oxide (SiOx), or an organic insulating material, such as acrylic, polyimide or benzocyclobutene (BCB), etc. The passivation film  250  may have a single-layer structure or a multi-layer structure made of an organic insulating material or/and an inorganic insulating material. The passivation film  250  is formed to cover the TFT and the gate insulating layer  220 , thereby insulating the TFT from the pixel electrode  260 . 
     The passivation film  250  has first contact hole  251  which exposes a portion of the drain electrode  243 . The first contact hole  251  is formed by etching corresponding portions of the passivation film  250  through a photolithography process. 
     The pixel electrode  260  is formed on the passivation film  250 . The pixel electrode  260  is electrically connected to the drain electrode  243  of the TFT via the first contact hole  251 . The pixel electrode  260  is made of a transparent conductive material such as ITO, IZO, indium tin zinc oxide (ITZO), or tin oxide (TO). 
     The first substrate  200  may further include an alignment layer (not drawn) on the pixel electrode  260 . 
       FIG. 4  is a cross-sectional view taken along line II-II′ of  FIG. 2 . 
     The first substrate  100  includes a touch spacer  141  formed on the overcoat layer  130 . A protrusion for touch spacer  140  is formed on the overcoat layer  130  and the protrusion for touch spacer  140  is covered with the common electrode  150 . That is, the touch spacer  141  includes the protrusion for touch spacer  140  and the common electrode  150 . The touch spacer  141  has a predetermined height, i.e., a convex shape so that the common electrode  150  contacts first and second sensing electrodes  270  and  280  of the second substrate when a surface of the upper substrate  101  is touched by a user&#39;s finger or a stylus pen. A predetermined gap is kept between the touch spacer  141  and the first and second sensing electrodes  270  and  280  until a user touches a surface of the upper substrate  101 . Also, when a user touches a surface of the upper substrate  101 , the touch spacer  141  has the common electrode  150  to contact the first and second sensing electrodes  270  and  280  so that the contact point can be detected. In this embodiment of the invention, the height of the touch spacer  141  is smaller than that of the column spacer which maintains a cell gap between the first substrate and the second substrate (shown in  FIG. 1 ). 
     In some embodiments of the invention, the protrusion for touch spacer  140  may be made of a conductive material so that a voltage or an electrical current can be applied between the common electrode  150  and the first and second sensing electrodes  270  and  280  when the common electrode  150  gets damaged. And moreover the touch spacer  141  may be made of a conductive material itself without the common electrode  150 . 
     The second substrate includes the first sensing line  215 , the second sensing line  245  and the first and second sensing electrodes  270  and  280  which are formed on a lower substrate  201 . 
     The first sensing line  215  may be made of the same material in the same layer as the gate line  210  (in  FIG. 2 ). The second sensing line  245  may be made of the same material in the same layer as the data line  240  (in  FIG. 2 ). 
     The gate insulating layer  220  is formed on the first sensing line  215  and the second sensing line  245  is formed on the gate insulating layer  220 . The passivation film  250  is formed over the second sensing line  245 . 
     The passivation film  250  has second and third contact holes  252  and  253  which expose portions of the first and second sensing lines  215  and  245 , respectively. The second and third contact holes  252  and  253  are formed by etching corresponding portions of the passivation film  250  through a photolithography process. 
     The first and second sensing electrode may be formed of the same material of the pixel electrode which is a transparent conductive material. The first sensing electrode  270  includes a first electrode contact portion  271  which electrically contacts the first sensing line  215  and a first electrode extending portion  272  which extends from the first electrode contact portion  271 . The second sensing electrode  280  includes a second electrode contact portion  281  which electrically contacts the second sensing line  245  and a second electrode extending portion  282  which extends from the second electrode contact portion  281 . The first and second electrode extending portions  272  and  282  may have various shapes. The first and second electrode extending portions  272  and  282  may be alternately formed or symmetrically formed as if they engage each other. 
     The first electrode contact portion  271  of the first sensing electrode  270  is electrically connected to the first sensing line  215  via the second contact hole  252  which penetrates the passivation film  250  and the gate insulating layer  220 . In  FIG. 4  the second contact hole  252  exposes the second substrate  201  and the second contact hole  252  may expose some portion of the first sensing electrode  215 . The first electrode extending portion  272  of the first sensing electrode  270  is formed on the passivation film  250  in a predetermined pattern to face the second sensing electrode  280 . 
     The second electrode contact portion  281  of the second sensing electrode  280  is electrically connected to the second sensing line  245  via the third contact hole  253  which penetrates the passivation film  250 . The second electrode extending portion  282  of the second sensing electrode  280  is formed on the passivation film  250  in a predetermined pattern to face the first sensing electrode  270 . Here, the second electrode extending portion  282  may be formed on the passivation film  250  at the same height as the first electrode extending portion  272  of the first sensing electrode  270 . Therefore, when the panel is touched, the touch spacer  141  equally contacts the first and second sensing electrodes  270  and  280 . 
     The first and second sensing electrodes  270  and  280  form a concave surface, i.e. the first and second electrode extending portions  272  and  282  together form a concave surface facing the touch spacer  141  as shown in  FIG. 4 . A patterned passivation film makes up the upper part of the first and second electrode extending portion  272  and  282 , which are located in the edge of the first and second electrode extending portion  272  and  282 . An exposed gate insulating layer makes up a lower part of the first and second electrode extending portion  272  and  282 , which is located inward toward the middle portion of the touch point. 
     For this concave surface of the sensing electrode, the passivation film and the gate insulating layer can make a concave surface like a well for sensing electrodes  270  and  280 . 
     If the display panel is touched by a user, the touch spacer  141  may contact the concave surface of the sensing electrode, i.e. the first and second electrode extending portion  272  and  282 . Because the surface of the sensing electrode is concave, the touch spacer has more of a chance to contact the sensing electrodes  270  and  280  through a bottom surface and a side wall surface of the touch spacer. The more chances to make contact between the touch spacer and the sensing electrode allows for better sensitivity of the display panel. 
     When a user drags some point or draws a picture, the touch event comprises an x, y, or z direction movement, so the touch spacer  141  may move downward in the x, y and z direction. The sensing electrodes  270  and  280  having a concave surface create more contact opportunities for the touch spacer  141 . Because the sensing electrodes  270  and  280  have a concave surface, the touch spacer  141  has more contact points in the x and y direction. The side wall of the sensing electrodes  270  and  280  may be contacted by the touch spacer  141 . 
     When the upper substrate  101  is touched by a user&#39;s finger or a stylus pen, the first and second sensing electrodes  270  and  280  are contacted through the touch spacer  141 , so that a resistance value varies depending on a contact position. Since an electrical current or voltage depends on the varied resistance value, the detected electrical current or voltage is outputted as a horizontal coordinate signal through the first sensing line  215  and as a vertical coordinate signal through the second sensing line  245 . The outputted coordinate signals are converted into coordinate values by a driving circuit, so that a command or an application program corresponding to the measured coordinate values is executed. 
     EMBODIMENT 2 
       FIG. 5  is a cross-sectional view illustrating a sensing portion of a display panel according to the second exemplary embodiment of the present invention; 
     The following explanation describes a second embodiment of the present invention. Here, for convenience of explanation, those members that have the same functions and that are described in  FIGS. 2 to 4  are indicated by the same reference numerals and the description thereof is omitted. 
     Referring to the  FIG. 5 , in the second embodiment of present invention, the first and second electrode extending portions  272  and  282  have an inclined portion facing touch spacer  141  on the upper substrate. Side walls of the concave the sensing electrodes  270  and  280  facing touch spacer  141  are sloped. The passivation film  250  has an inclined surface so that the sensing electrodes  270  and  280  can have a slope. The inclined side wall of the sensing electrode may face the edge of the touch spacer  141 , so the touch spacer&#39;s edge can safely contact sensing electrodes  270  and  280 . 
     For the inclined surface of the passivation film, the passivation film may be dry etched. If the passivation film is made of an organic photo sensitive material, a slit photo mask or half tone mask may be used in a photolithography method. 
     EMBODIMENT 3 
       FIG. 6  is a cross-sectional view illustrating a sensing portion of a display panel according to the third exemplary embodiment of the present invention. 
     The following explanation describes a third embodiment of the present invention. Here, for convenience of explanation, those members that have the same functions and that are described in  FIGS. 2 to 4  are indicated by the same reference numerals and the description thereof is omitted. 
     Referring to  FIG. 6 , the display panel includes an alignment layer in the first substrate and the second substrate. The alignment layer  290  is formed on the sensing electrodes  270  and  280  and the alignment layer  160  is formed on the touch spacer  141 . The alignment layers  160  and  290  in this embodiment of the invention are the uppermost layer in the first and second substrate to prevent disorientation of the liquid crystal molecules. The alignment layers may be made of an inorganic material or organic material. 
     The alignment layer  160  on the touch spacer has a thinner portion than the other portion of the alignment layer  160 . On the upper portion of the touch spacer, the alignment layer has a thinner thickness. The alignment layer  160  on the touch spacer becomes thinner as the alignment layer  160  is closer to the second substrate. It is better to transmit the current or voltage of the touch spacer  141 , the common voltage of the common electrode, to the sensing electrodes  270  and  280 . Because the function of the alignment layer is insulation from electricity therebetween, the thinner thickness of the alignment layer at the contact point makes allows for better sensitivity and better detecting efficiency for the touch event (the better transmission of the electricity). 
     In  FIG. 6 , the sensing electrode also has a concave surface in the sensing electrodes  270  and  280 . The thinner alignment layer  160  on the touch spacer can meet the curved surface of the sensing electrodes  270  and  280 . 
     EMBODIMENT 4 
       FIG. 7  is a cross-sectional view illustrating a sensing portion of a display panel according to the fourth exemplary embodiment of the present invention. 
     The following explanation describes a fourth embodiment of the present invention. Here, for convenience of explanation, those members that have the same functions and that are described in  FIGS. 2 and 3  are indicated by the same reference numerals and the description thereof is omitted. 
     Referring to  FIG. 7 , the first substrate  100  is similar to that of  FIG. 4 . So the explanation about the first substrate is omitted. The second substrate  200  includes the first sensing line  215 , the second sensing line  245  and the first and second sensing electrodes  270  and  280  which are formed on a lower substrate  201 . 
     The first sensing line  215  may be made of the same material in the same layer as the gate line  210  (in  FIG. 2 ). The second sensing line  245  may be made of the same material in the same layer as the data line  240  (in  FIG. 2 ). 
     The gate insulating layer  220  is formed on the first sensing line  215  and the second sensing line  245  is formed on the gate insulating layer  220 . The passivation film  250  is formed over the second sensing line  245 . 
     The passivation film  250  has second and third contact holes  252  and  253  which expose portions of the first and second sensing lines  215  and  245 , respectively. The second contact holes  252  are formed by etching corresponding portions of the passivation film  250  and the gate insulating layer  220  through a photolithography process, and the third contact holes  253  are formed by etching corresponding portions of the passivation film  250  through a photolithography process. 
     The first and second sensing electrodes  270  and  280  may be formed of the same material of the pixel electrode which is transparent conductive material on the passivation film. And the first sensing electrode  270  faces the second sensing electrode  280 . The first sensing electrode electrically contacts the first sensing line  215  through the second contact hole  252 . The side wall of the second contact hole may slope, which is formed by the photolithography method. The passivation film may be made of an organic material or an inorganic material. 
     The sloped side wall of the second contact hole  252  are inclined so that the sensing electrodes  270  and  280  have a concave surface facing the touch spacer  141  as shown in  FIG. 7 . The sensing electrodes  270  and  280  may have an inward curve in middle. 
     The second sensing electrode  280  electrically contacts the second sensing line  245  through the third contact hole  253 . The first and second electrodes  270  and  280  may have various shapes. Portions of the first and second electrodes  270  and  280  may be alternately formed or symmetrically formed as if they engage each other. 
     If the display panel is touched by user, the touch spacer  141  may contact the concave surface of the sensing electrode, i.e. the first and second electrodes  270  and  280 . Because the surface of the sensing electrode is concave, the touch spacer has more of a chance to contact the sensing electrodes  270  and  280  through a bottom surface and a side wall surface of the touch spacer. Sensitivity of the display panel is increased by providing more chances to make contact between the touch spacer  141  and the sensing electrodes  270  and  280 . 
     When a user drags some point or draws a picture, the touch event comprises an x, y, or z direction movement, so the touch spacer  141  may move downward in the x, y and z direction. The sensing electrodes  270  and  280  having a concave surface make more contact opportunity for the touch spacer  141 . Because the sensing electrodes  270  and  280  have a concave surface, the touch spacer  141  has more contact points in the x and y direction. The side wall of the sensing electrodes  270  and  280  may be contacted by the touch spacer  141 . 
     &lt;Manufacturing Method&gt; 
     A method for manufacturing a liquid crystal display panel according to an exemplary embodiment of the present invention is described below. 
     The method for manufacturing a display panel according to an exemplary embodiment of the present invention includes forming a first substrate (i.e., color filter array substrate) and forming a second substrate (i.e., TFT array substrate). 
     As shown in  FIG. 3 , a black matrix  110  is formed on an upper substrate  101 . 
     The black matrix  110  is formed such that an opaque organic material layer or an opaque metal layer is deposited on the upper substrate  101  and is patterned by a photolithography process and an etching process. The black matrix  110  is formed at a predetermined width to prevent opaque metal patterns of the second substrate from being seen. The upper substrate  101  is made of a transparent insulating material such as plastic so that it can be smoothly pushed when its surface is touched. 
     A color filter layer  120  is formed on the upper substrate  101  having the black matrix  110  as shown in  FIG. 3 . The color filter layer  120  is formed such that red (R), green (G) and blue (B) color filters are formed by a photolithography method. The color filters may be formed by an ink jet method. 
     Next, as shown in  FIG. 3 , an overcoat layer  130  is formed over the whole surface of the upper substrate  101  to cover the black matrix  110  and the color filter layer  120 . 
     The overcoat layer  130  is formed at a predetermined thickness to protect the color filter layer  120  and to obtain excellent step coverage when a common electrode  150  is formed. The overcoat layer  130  may be formed by depositing acrylic resin using, for example, a spin coating technique. 
     Then, as shown in  FIG. 4 , a touch spacer  141  is formed on the overcoat layer  130  by using an organic material or an inorganic material. 
     In order to form the touch spacer  141 , an organic layer is deposited over the whole surface of the upper substrate  101 . A photoresist is coated on the organic layer and is subjected to a light exposure process and a development process of a photolithography process to thereby form a photoresist pattern. The organic layer is patterned by an etching process using the photoresist pattern as a mask, thereby forming a protrusion for the touch spacer  140 . The organic layer may be formed using a photosensitive organic layer without a photoresist. The organic layer may be formed by using an inkjet printing method. The touch spacer  141  may be made in various forms. 
     Subsequently, as shown in  FIG. 4 , the common electrode  150  is formed over the whole surface of the upper substrate  101  to cover the overcoat layer  130  and the protrusion for touch spacer  140 . 
     In more detail, a transparent conductive material layer is deposited over the whole surface of the upper substrate  101  to cover the overcoat layer  130  and the protrusion for touch spacer  140  by using, for example, a sputtering technique. The transparent conductive material layer is made of a transparent conductive material such as ITO or IZO. The transparent conductive material layer may be patterned into the common electrode  150  by a photolithography process and an etching process using a mask. 
     Next, as shown in  FIG. 6 , an alignment layer is formed on the common electrode  150 . The alignment layer may be made of an inorganic material or an organic material. If an organic material is used, the alignment layer can be formed using a roll coating printing method, a spin coating method, an ink jet printing method, etc. When the alignment layer is formed by a coating method, a coated organic material is flown down through the slopes of the substrate and the upper portion of the touch spacer  141  may have the thinner thickness of the alignment layer. 
     The steps of forming the second substrate are described below in detail with reference to  FIGS. 2 to 4 . 
     A gate metal pattern having a gate line  210 , a gate electrode  211  and a first sensing line  215  is formed on a lower substrate  201 . The gate metal pattern is formed such that a gate metal layer is deposited by a deposition technique such as a sputtering technique and is then patterned by a photolithography process and an etching process. The lower substrate  210  is made of a transparent insulating material such as glass or plastic. 
     The gate line  210  is formed in a first direction, and the gate electrode  211  extends from the gate line  210 . The first sensing line  215  is formed in the first direction parallel with the gate line  210 . The first sensing line  215  is apart from the gate line  210 . For example, the first sensing line  215  is at a distance of about 5 μm from the gate line  210 . 
     Then, as shown in  FIGS. 3 and 4 , a gate insulating layer  220  is formed over the whole surface of the lower substrate  201  having the gate metal pattern by using a plasma enhanced chemical vapor deposition (PECVD) technique. The gate insulating layer  220  is formed by depositing an insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) over the whole surface of the lower substrate  201 . The gate insulating layer  220  is formed to cover the gate metal pattern formed on the lower substrate  201 , thereby electrically insulating the gate metal pattern. 
     As shown in  FIG. 3 , a semiconductor layer  230  includes an active layer  231 . An ohmic contact layer  233  is formed on a portion of the gate insulating layer  220  over the gate electrode  211 . The active layer  231  is formed such that a poly-silicon layer or an amorphous silicon layer is deposited and patterned by a photolithography process and an etching process, and the ohmic contact layer  233  is formed such that a doped poly-silicon layer or a doped amorphous silicon layer is deposited and patterned by a photolithography process and an etching process. 
     Subsequently, as shown in  FIGS. 2 to 4 , a data metal pattern having a data line  240 , a source electrode  241 , a drain electrode  243 , and a second sensing line  245  is formed on the lower substrate  201  having the semiconductor layer  230 . 
     In more detail, the data metal pattern is formed such that a metal layer is deposited on the lower substrate  201  having the semiconductor layer  230  and patterned by a photolithography process and an etching process. 
     The data line  240  is formed to cross the gate line  210 . One side of the drain electrode  243  faces the source electrode  241 , and the other side is electrically connected to the pixel electrode  260  to have a wider area on one side. 
     As shown in  FIGS. 2 to 4 , a passivation film  150  is formed over the whole surface of the lower substrate  201 . First to third contact holes  251  to  253  are formed in the passivation film  250 . 
     The passivation film  250  is formed over the whole surface of the lower substrate  201  by using a deposition technique such as a PECVD technique or a spin coating technique. The first and third contact holes  251  and  253  are formed by a photolithography process and an etching process using a mask to penetrate the passivation film  250 . At the same time, the second contact hole is formed to penetrate the passivation film  250  and the gate insulating layer  220 . The first contact hole  251  exposes a portion of the drain electrode  243 . The third contact hole  253  exposes a portion of the second sensing line  245 , and the second contact hole  252  exposes a portion of the first sensing line  215 . The passivation film  250  may be formed of an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) or an organic insulating material such as acrylic, polyimide or benzocyclobutene (BCB). 
     Thereafter, as shown in  FIGS. 2 to 4 , a pixel electrode  260  and first and second sensing electrodes  270  and  280  are formed on the passivation film  250 . 
     More specifically, a transparent conductive material layer such as ITO, IZO or TO is deposited on the passivation film  250  by using a deposition technique such as a sputtering technique and then patterned by a photolithograph process and an etching process using a mask, thereby forming the pixel electrode  260  in a pixel region. 
     The first and second sensing electrodes  270  and  280  may be formed on the passivation film  250  at the same height as in  FIG. 4 . The first and second sensing electrodes  270  and  280  are electrically connected to the first and second sensing lines  215  and  245  via the second and third contact holes  252  and  253 , respectively. The first sensing electrode  270  is electrically connected to the first sensing line  215  via the second contact hole  252  and a portion of the first sensing electrode  270  is extended toward the second contact electrode  280 . The second sensing electrode  280  is electrically connected to the second sensing line  245  via the third contact hole  253  and a portion of the second sensing electrode  280  is extended toward the first sensing electrode  270 . 
     Next, as shown in  FIG. 6 , an alignment layer  290  is formed on the sensing electrodes  270  and  280 . The alignment layer may be made of an inorganic material or organic material. If an organic material is used, the alignment layer is formed using a roll coating printing method, a spin coating method, an ink jet printing method, etc. 
     Next, the first substrate  100  and the second substrate  200  are attached and a liquid crystal  300  is interposed. The liquid crystal may be dropped on the first substrate or the second substrate by one drop filing method and then the two substrates may be attached.