Abstract:
An LCD and a touch display panel that can be integrated in the LCD are provided. The touch display panel comprises an active device matrix substrate that includes multiple sensing lines disposed on multiple data lines correspondingly and arranged parallel thereto, and multiple sensing devices formed on multiple scan lines. When an external pressure is exerted, a current is generated in the sensing lines, and the X and Y coordinates of the touch point is determined from a slight leakage current generated in the scan lines. The conventional external touch screen LCD device is substantially improved in response accuracy of the touch coordinates, material costs, and mechanical thickness.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 97150574, filed Dec. 25, 2008. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a touch display panel and a liquid crystal display (LCD). More particularly, the present invention relates to an LCD with a built-in touch display panel suitable for being pressed by a finger or a stylus. 
     2. Description of Related Art 
     Several types of touch display panels are now commonly employed in display that require both display and input capabilities, such as resistance sensing, capacitance sensing, and wave sensing (e.g., acoustic, infrared, or laser) touch display panels. Referred to as the external touch LCD, resistance and capacitance sensing touch LCD are implemented by stacking a touch display panel and an LCD. Since the stacked touch display panel is transparent, images can be transmitted to overlap with the touch screen images above, where the touch display functions as an input interface. However, in these conventional techniques, incorporation of an additional touch display panel significantly increases the total weight of the LCD. Consequently, market demands of a thin, lightweight display is not met. Also, directly stacking the touch display panel and the LCD significantly increases the thickness of the touch LCD. Additionally, a rubber cushion is often placed in between the touch display panel and the LCD in order to reduce vibrations. Therefore, conventional touch LCD often face a significant increase in thickness, causing loss of device mobility. Furthermore, because light has to pass through a plurality of layers in the touch display panel, absorption significantly reduces light transmittance. Moreover, touch-points on the resistance sensing, capacitance sensing, and the wave sensing touch LCDs are not the actual imaged points on the panel. Therefore, there is a discrepancy between the touch coordinates and the actual imaged points on the panel. Accordingly, what is desired is a touch LCD that is lightweight, thin, and accurate in reflecting the touch position. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to providing an LCD with a built-in touch display panel, in order to more accurately respond to the touch coordinates and to substantially reduce the material costs and the mechanical thickness of the conventional external touch LCD. 
     In the present invention, a touch screen LCD panel including an active device matrix substrate, an opposite substrate, and a liquid crystal layer is provided. The active device matrix substrate includes a plurality of data lines, a plurality of scan lines, a plurality of active devices, a plurality of pixel electrodes, a plurality of sensing lines, and a plurality of sensing devices. The opposite substrate is disposed opposing the active device matrix substrate, and the opposite substrate includes a black matrix, an opposite electrode, a plurality of first pillars, and a plurality of second pillars. The first and second pillars are respectively disposed opposing the sensing lines and the sensing devices. The liquid crystal layer is disposed between the active device matrix substrate and the opposite substrate. According to an external pressure, at least one of the first pillars is electrically connected to least one of the sensing lines and at least one of the second pillars is electrically connected to least one of the sensing devices. 
     The present invention further provides an LCD device that includes a touch display panel and a backlight module. The touch display panel includes an active matrix panel, an opposite substrate, and a liquid crystal layer. The active device matrix substrate includes a plurality of data lines, a plurality of scan lines, a plurality of active devices, a plurality of pixel electrodes, a plurality of sensing lines, and a plurality of sensing devices. The opposite substrate is disposed opposing the active device matrix substrate, and the opposite substrate includes a black matrix, a plurality of opposing electrodes, a plurality of first pillars, and a plurality of second pillars. The first and second pillars are respectively disposed opposing the sensing lines and the sensing devices. The liquid crystal layer is disposed between the active device matrix substrate and the opposite substrate. According to an external pressure, at least one of the first pillars is electrically connected to least one of the sensing lines and at least one of the second pillars is electrically connected to at least one of the sensing devices. The backlight module is disposed at a side of the active device matrix substrate away from the opposite substrate. The backlight module is a side-edge type backlight module or a direct-type backlight module, for instance. 
     In summary, embodiments of the present invention may provide an LCD with a built-in touch display panel by integrating the sensing lines and the sensing devices on the active device matrix substrate and disposing a plurality of touch-points on the opposite substrate. Consequently, substantial improvements are made to the conventional external touch LCD in response accuracy of the touch coordinates, the manufacturing cost (without additional fabrication steps for the sensing lines and the sensing devices), and the mechanical thickness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic view of a touch liquid crystal display (LCD) in accordance with one embodiment of the present invention. 
         FIG. 2  is a partially magnified schematic view of an active device matrix substrate in accordance with the present invention. 
         FIG. 3  is a schematic view along an A-A′ cross-section of a sensing line on the active device matrix substrate in accordance with the present invention. 
         FIG. 4  is a schematic view along a B-B′ cross-section of a sensing device on the active device matrix substrate in accordance with the present invention. 
         FIG. 5  is a schematic top view of a film surface of an opposite substrate in accordance with the present invention. 
         FIG. 6  is a schematic view of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. 
         FIGS. 7A and 7B  are schematic view along the A-A′ cross-section of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. 
         FIGS. 8A and 8B  are schematic view along the B-B′ cross-section of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In order to make aforementioned and other objects, features, and advantages of the present invention more comprehensible, several embodiments accompanied with figures are described in detail underneath. It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
     Referring to  FIG. 1 ,  FIG. 1  is a schematic view of a touch liquid crystal display (LCD) in accordance with one embodiment of the present invention. As shown in  FIG. 1 , the touch LCD  10  of the present embodiment includes a touch display panel  20  and a backlight module  30 . The touch display panel  20  includes an active device matrix substrate  21 , an opposite substrate  22  that is disposed opposing the active device matrix substrate  21 , and a liquid crystal layer  23  that is disposed between the active device matrix substrate  21  and the opposite substrate  22 . The backlight module  30  is disposed at a side of the active device matrix substrate  21  away from the opposite substrate  22 . The backlight module  30  is a side-edge type backlight module or direct-type backlight module, for instance. 
     A detailed depiction of the active device matrix substrate  21  can be found in  FIG. 2 .  FIG. 2  is a partially magnified schematic view of an active device matrix substrate in accordance with the present invention. As shown in  FIG. 2 , major components of an LCD panel such as a plurality of scan lines  211 , a plurality of data lines  213 , a plurality of active devices  218 , and a plurality of pixel electrodes  215  are disposed on the active device matrix substrate  21 . The scan lines  211  cross the data lines  213  perpendicularly. The active devices  218  can be thin film transistors (TFTs) disposed on a plurality of intersections of the data lines  213  and the scan lines  211 . The pixel electrodes  215  are electrically connected to the active devices  218  for receiving a driving signal from the data lines  213 . A plurality of sensing lines  216  are disposed on the data lines  213  and arranged parallel thereto. A plurality of sensing devices  217  are disposed on the scan lines  211 . 
     A detailed depiction of the sensing line  216  can be found in  FIG. 3 .  FIG. 3  is a schematic view along an A-A′ cross-section of a sensing line on the active device matrix substrate in accordance with the present invention. As shown in  FIG. 3 , a gate insulating layer  212  is formed on a substrate  210 . The data line  213  is formed on the gate insulating layer  212 . The sensing line  216  is disposed on the data line  213  and arranged parallel thereto. A passivation layer  214  is disposed between the data line  213  and the sensing line  216  in order to electrically insulate these two conductive layers. The sensing line  216  and the pixel electrode  215  (see  FIG. 2 ) are formed in a same layer process. 
     A detailed depiction of the sensing device  217  can be found in  FIG. 4 .  FIG. 4  is a schematic view along a B-B′ cross-section of a sensing device on the active device matrix substrate in accordance with the present invention. As shown in  FIG. 4 , a gate  2171 , the passivation layer  212 , a semiconductor layer  2176 , a source  2172 , and a drain  2173  are sequentially formed on the substrate  210 . The sensing device  217  can be a TFT having the gate  2171  that is formed with the scan line  211  in a same layer process. The sensing device  217  has a source  2172  and a drain  2173  that are formed with the data line  213  in a same layer process. The gate  2171  and the source  2172  of the sensing device  217  are electrically connected via a transparent conductive layer  2174 . The drain  2173  of the sensing device  217  is electrically connected with a sensing electrode  2175 . The sensing line  216 , the transparent conductive layer  2174 , the sensing electrode  2175 , and the pixel electrode  215  are formed in a same layer process. 
     In order to substantially improve a touch capability of the touch display panel  20 , a plurality of touch-points is disposed on the opposite substrate  22  (see  FIG. 1 ). Detailed depiction of the touch-points can be found in  FIG. 5 .  FIG. 5  is a schematic top view of a film surface of an opposite substrate in accordance with the present invention. As shown in  FIG. 5 , the opposite substrate  22  of the present embodiment includes a black matrix  221 , a first pillar  222 , a second pillar  223 , and an opposite electrode  224 . The first pillar  222  and the second pillar  223  are disposed on the black matrix  221 . The opposite electrode  224  covers the first pillar  222  and the second pillar  223 . 
     After panel assembly, as depicted in  FIG. 6 , the aforementioned first pillar  222  and the second pillar  223  are each respectively disposed opposing the sensing line  216  and the sensing device  217 .  FIG. 6  is a schematic view of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. As shown in  FIG. 6 , the first pillar  222  is disposed opposing the sensing line  216 , and the second pillar  223  is disposed opposing the sensing device  217 . When an external pressure is exerted on the touch display panel  20 , the first pillar  222  near a press-point is electrically connected to the sensing line  216 , while the second pillar  223  near the press-point near is electrically connected to the sensing device  217 . 
       FIGS. 7A and 7B  are schematic view along the A-A′ cross-section of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. As shown in  FIG. 7A , the black matrix  221  is formed on a substrate  220  of the opposite substrate  22 . The first pillar  222  is disposed on the black matrix  221  and arranged opposing the sensing line  216 . A height of the first pillar  222  is approximately less than a panel spacing of 1 μm. The opposite electrode  224  is disposed opposing the active device matrix substrate  21 , and the opposite electrode  224  covers the first pillar  222 . Referring to  FIG. 7B , when the external pressure causes the opposite electrode  224  on the first pillar  222  to electrically connect with the sensing line  216 , due to the opposite electrode  224  having a Vcom voltage, the sensing line  216  generates a sensing current. The sensing current is detected by a receiving terminal of the data line  213  (not drawn, disposed at an opposite side of a transmitting terminal of the data line  213 ). Consequently, an X coordinate of the touch-point is determined. 
       FIGS. 8A and 8B  are schematic view along the B-B′ cross-section of the active device matrix substrate after assembly with the opposite substrate in accordance with the present invention. As shown in  FIG. 8A , the black matrix  221  is formed on the substrate  220  of the opposite substrate  22 . The second pillar  223  is disposed on the black matrix  221  and arranged opposing the sensing electrode  2175  of the sensing device  217  (see  FIG. 6 ). A height of the second pillar  223  is approximately less than the panel spacing of 1 μm. The opposite electrode  224  is disposed opposing the active device matrix substrate  21 , and the opposite electrode  224  covers the second pillar  223 . Referring to  FIG. 8B , when external pressure causes the opposite electrode  224  of the second pillar  223  to electrically connect with the sensing electrode  2175 , a signal transmitting from the scan line  211  to the opposite electrode  224  has a slight leakage current. Consequently, a slight current anomaly can be detected in the current of the scan line  211 . The slight leakage current can be detected by a receiving terminal of the scan line  211  (not shown, disposed at an opposing side to a transmitting terminal of the scan line  211 ). Consequently, an Y coordinate of the touch-point is determined. 
     Accordingly, embodiments of the present invention may provide an LCD with a built-in touch display panel that is implemented by disposing a parallel sensing line on a data line of an active device matrix substrate. In addition, a sensing device is disposed on the scan line. When an external pressure is exerted, the sensing device provides a current on the sensing line, the sensing line being located on the date line. Furthermore, a scan line generates a leakage current, from which a determination of the X and Y coordinates of the touch-point may be made. Embodiments of the present invention may provide an LCD with a built-in touch display panel that responds to touch coordinates more accurately. The additional sensing line and the sensing device are compatible with the available manufacturing techniques, and no extra fabrication steps are needed. Consequently, embodiments of the present invention may substantially improve upon the conventional external touch LCD in its material costs and its mechanical thickness. 
     Although the present invention has been disclosed by the above embodiments, they are not intended to limit the present invention. Anybody skilled in the art may make some modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the protection range of the present invention falls in the appended claims.