Patent Publication Number: US-2011075059-A1

Title: Liquid crystal display touch panel

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to liquid crystal displays (LCDs), and more particularly, to an integrated LCD touch panel. 
     2. Description of the Related Art 
     Touch panels of an electronic device detect contact with a display surface and use the detected contact to implement desired operations of the electronic device. Analog resistive, capacitive, electromagnetic, surface acoustic wave, and infrared touch panels are all popularly used. Often, an LCD touch panel can be either a conventional LCD combined with an external touch panel, or an integrated LCD touch panel. Compared with the combined LCD touch panel, the integrated LCD touch panel provides a clearer image and higher display performance at low cost. 
     Referring to  FIGS. 7 and 8 , a typical integrated LCD touch panel  80  includes a TFT (Thin Film Transistor) substrate  81 , and a color filter substrate  82  opposite thereto. The TFT substrate  81  includes a number of X sensor lines  811 , a number of Y sensor lines  812 , and a number of detection electrodes  813 . The X sensor lines  811  are parallel to each other and evenly spaced on the TFT substrate  81 . The Y sensor lines  812  are parallel to each other and evenly spaced on the TFT substrate  81 . The X sensor lines  811  intersect with the Y sensor lines  812 , and the X and Y sensor lines  811 ,  812  cooperatively define a number of sub-pixel areas. The detection electrodes  813  are arranged on the TFT substrate  81  adjoining the X sensor lines  811  and the Y sensor lines  812 . The color filter substrate  82  includes a number of contact electrodes  821  (see  FIG. 7 ) and a common electrode layer (not labeled) electrically connected to the contact electrodes  821 . Contact by an external object with an outer surface of the color filter substrate  82  moves a contact electrode  821  corresponding to the contact position toward the TFT substrate  81  whereby the contact electrode  821  makes contact with one of the detection electrodes  813 . A voltage between the detection electrode  813  and the X sensor line  811 , and a voltage between the detection electrode  813  and the Y sensor line  812  are both changed. As a result, a driving control module (not shown) electrically connected to the X and Y sensor lines  811 ,  812  determines the touch position via the X and Y sensor lines  811 ,  812 . 
     However, an aperture ratio of the integrated LCD touch panel is reduced due to the detection electrodes  813  sharing the sub-pixel areas. In addition, a cost of the integrated LCD touch panel is unduly high due to the employment of many X and Y sensor lines  811 ,  812 . Furthermore, when the contact electrode  821  contacts the detection electrodes  813 , the contact electrode  821  generates a short circuit with the X sensor line  811  and the Y sensor line  812 . This causes voltage drift between the common electrode layer and a pixel electrode (not shown), which degrades the display quality. 
     Therefore, there is room for improvement within the art. 
     SUMMARY 
     According to one aspect of the present disclosure, there is provided an integrated liquid crystal display (LCD) touch panel. An embodiment of the disclosure discloses an LCD touch panel includes a first substrate, a second substrate, a liquid crystal layer and a driving control module. The first substrate includes scan lines, data lines and contact sensor modules. Each contact sensor module includes a sensor readout line parallel to a corresponding data line, a readout transistor electrically connected to the sensor readout line and a corresponding scan line, and a contact electrode electrically connected to the readout transistor. The second substrate is parallel to the first substrate, and includes protrusions at a surface of the second substrate which faces toward the first substrate. The protrusions are positioned opposite to the contact electrodes, respectively. The liquid crystal layer is sandwiched between the first substrate and the second substrate. The driving control module is electrically connected to the sensor readout lines and the data lines. Each of the readout transistors is in a readout state when the readout transistor receives an input voltage from the adjacent scan line; and when the second substrate is elastically deformed one of the protrusions electrically contacts the corresponding contact electrode and the readout transistor receives a voltage signal from the contact electrode such that the readout transistor is activated and sends a sensing signal to the driving control module, which detects the position of the contacted readout transistor via the adjacent scan line and the corresponding sensor readout line. 
     An embodiment of the disclosure discloses an LCD touch panel includes a thin film transistor (TFT) substrate and a color filter (CF) substrate. The TFT substrate includes parallel scan lines, parallel data lines, sensor readout lines and contact sensor modules. The scan lines and the data lines cooperatively define a plurality of sub-pixel areas. The sensor readout lines are adjacent and parallel to the data lines, respectively. The contact sensor modules are disposed in the sub-pixel areas, respectively. Each contact sensor module includes a readout transistor electrically connected to a corresponding adjacent sensor readout line and a corresponding adjacent scan line, and a contact electrode electrically connected to the readout transistor. The CF substrate is parallel to the TFT substrate, and includes protrusions, a liquid crystal layer and a driving control module. The protrusions are located at an inner surface of the CF substrate, and positioned opposite to the contact electrodes, respectively. The liquid crystal layer is sandwiched between the TFT substrate and the CF substrate. The driving control module is electrically connected to the sensor readout lines and the data lines. Each of the readout transistors is in a readout state when the readout transistor receives an input voltage from the adjacent scan line; and when an outside of the second substrate is pressed inward one of the protrusions electrically contacts the corresponding contact electrode and the readout transistor receives a voltage signal from the contact electrode such that the readout transistor is activated and sends a sensing signal to the driving control module, which detects the position of the contacted readout transistor via the adjacent scan line and the corresponding sensor readout line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, and all the views are schematic. 
         FIG. 1  is essentially a plan view of a sub-pixel region of a first embodiment of a liquid crystal display with an internal touch panel. 
         FIG. 2  is a cross-section of part of the liquid crystal display of  FIG. 1 , corresponding to line II-II thereof. 
         FIG. 3  is similar to  FIG. 2 , but shows the sub-pixel region when the internal touch panel is pressed. 
         FIG. 4  is essentially a plan view of a sub-pixel region of a second embodiment of a liquid crystal display with an internal touch panel. 
         FIG. 5  is a cross-section of part of the liquid crystal display of  FIG. 4 , corresponding to line V-V thereof. 
         FIG. 6  is similar to  FIG. 5 , but shows the sub-pixel region when the internal touch panel is pressed. 
         FIG. 7  is a cross-section of a pixel region of a typical liquid crystal display with an internal touch panel, the liquid crystal display also including a TFT substrate and a color filter substrate. 
         FIG. 8  is a plan view of the TFT substrate of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a first embodiment of an integrated LCD touch panel  100  includes a first substrate  10 , a second substrate  20 , a liquid crystal layer  30  and a driving control module  40 . The first substrate  10  is parallel to the second substrate  20 . The liquid crystal layer  30  is sandwiched between the first substrate  10  and the second substrate  20 . The driving control module  40  is configured to detect contact that occurs with an external surface of the second substrate  20 . Such contact is typically a user&#39;s fingertip or stylus touching the external surface of the second substrate  20 . 
     The first substrate  10  includes a main body  11 , a number of scan lines  12 , a number of data lines  14 , a number of sub-pixel driving control modules  16 , and a number of contact sensor modules  18 . The scan lines  12  are arranged at a surface of the main body  11  facing the second substrate  20 , and are parallel to each other and evenly spaced from each other. The data lines  14  are parallel to each other and evenly spaced from each other, and intersect with the scan lines  12 . The scan lines  12  and the data lines  14  cooperatively define a number of sub-pixel areas (not labeled). The sub-pixel driving control modules  16  and the contact sensor modules  18  are in each of the sub-pixel areas. 
     Each sub-pixel driving control module  16  includes a display control transistor  162  and a sub-pixel electrode  164 . The display control transistor  162  is respectively electrically connected to the adjacent scan line  12 , the adjacent data line  14 , and the sub-pixel electrode  164 . Each sub-pixel driving control module  16  further includes a driving control chip (not shown) electrically connected to the scan lines  12  and the data lines  14 . The driving control chip controls an on-off status of the display control transistor  162  and a voltage of the sub-pixel electrode  164 . 
     Each contact sensor module  18  is located in the vicinity of a corresponding intersection of the scan lines  12  and the data lines  14 . Each contact sensor module  18  includes a sensor readout line  182 , a readout transistor  184 , and a contact electrode  186 . The sensor readout line  182  is parallel to the data line  14 . The readout transistor  184  is electrically connected to the adjacent sensor readout line  182 , the adjacent data line  14 , and the contact electrode  186 . The scan line  12  inputs a voltage to the readout transistor  184 , such that the readout transistor  184  is in a readout state. When the readout transistor  184  is in a readout state, the contact electrode  186  sends a sensor voltage signal to the readout transistor  184 , and the readout transistor  184  is activated and sends a sensing signal to the driving control module  40  via the sensor readout line  182 . The driving control module  40  detects the position of the contacted readout transistor  184  via the adjacent scan line  12  and the adjacent sensor readout line  182 . 
     In the illustrated embodiment, the readout transistor  184  is a MOSTFT (Metal-Oxide Semiconductor Field Effect Transistor). The readout transistor  184  includes a gate electrode  1842 , a source electrode  1844  and a drain electrode  1846 . The gate electrode  1842  is electrically connected to the scan line  12 . The source electrode  1844  is electrically connected to the sensor readout line  182 . The drain electrode  1846  is electrically connected to the contact electrode  186 . In one embodiment, for instance, a protection layer  1848  covers the drain electrode  1846 . The protection layer  1848  defines a through hole (not labeled) to partially receive the contact electrode  186 , such that the contact electrode  186  electrically contacts the drain electrode  1846 . The readout transistor  184  is formed by a fourth photo-etching process (PEP4) or a fifth photo-etching process (PEPS). 
     The second substrate  20  includes a main body  21 , a number of protrusions  22 , a common electrode  23 , and a color filter layer (not labeled). The color filter layer is on an inner surface of the main body  21  which faces toward the first substrate  10 . The color filter layer includes a number of red, green and blue filter units. The protrusions  22  are provided on a surface of an underside of the color filter layer, and are positioned opposite to the contact electrodes  186 , respectively. The common electrode  23  is plated on the surface of the color filter layer and the protrusions  22 , so that the surface of the color filter layer and the protrusions  22  conduct electricity. A voltage can thus be generated between the common electrode  23  and the sub-pixel electrode  164  of each sub-pixel area. 
     Referring also to  FIG. 3 , contact with an outer surface of the second substrate  20  elastically deforms the second substrate  20  and moves one or more of the protrusions  22  corresponding to the touch position toward the first substrate  10 . In the following description, it is assumed that only one protrusion  22  moves. The protrusion  22  moves until the common electrode  23  contacts the contact electrode  186 . A voltage signal is transmitted from the common electrode  23  to the readout transistor  184  via the contact electrode  186 . The readout transistor  184  is activated, such that a current is transmitted from the drain electrode  184  to the sensor readout line  182  via the source electrode  1844 . The driving control module  40  detects a position of the contacted readout transistor  184  via the sensor readout line  182  and the scan line  12 , such that the driving control module  40  detects the contact position. 
     The gate electrode  1842  of the readout transistor  184  is electrically connected to the scan line  12 , and the driving control module  40  receives a sensing signal from the scan line  12  by scanning. Thus the driving control module  40  can quickly detect the contact position. The contact sensor module  18  and the sub-pixel driving control module  16  share the same scan line  12 , and do not need a number of X sensor lines. Thus an aperture ratio of the liquid crystal display with the internal touch panel  100  is increased. The readout transistor  184  can eliminate voltage drift between the common electrode  23  and the sub-pixel electrode  164 , and thus optical viewing characteristics of the integrated LCD touch panel are improved. 
     It is to be understood that fewer contact sensor modules  18  than data lines  14  can be deployed, and fewer readout transistors  184  than display control transistors  162  can be deployed. 
     Referring to  FIGS. 4 to 6 , a second embodiment of an integrated LCD touch panel  200  differs from the first embodiment of the integrated LCD touch panel  100  only in that a readout transistor  194  includes a gate electrode  1942 , a source electrode  1944 , a drain electrode  1946  and an oxidation layer  1949 . The gate electrode  1942  is electrically connected to the contact electrode  186 . The source electrode  1944  is electrically connected to the sensor readout line  182 . The drain electrode  1946  is electrically connected to the scan line  12 . The oxidation layer  1949  covers the gate electrode  1942 . The oxidation layer  1949  defines a through hole  1948  to partially receive the contact electrode  186 , such that the contact electrode  186  electrically contacts the gate electrode  1942 . When the common electrode  23  is put into electrically contact with the contact electrode  186 , the readout transistor  194  is activated. Current is then transmitted from the drain electrode  1946  to the source electrode  1944 , such that the driving control module  40  receives a voltage signal from the readout transistor  194  via the sensor readout line  182 . The contact electrode  186  electrically contacts the gate electrode  1942 , thus no voltage drift is generated between the common electrode  23  and the sub-pixel electrode  164 . 
     Finally, while the present disclosure has been described with reference to particular embodiments, the description is illustrative and is not to be construed as limiting the disclosure. Therefore, various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.