Abstract:
A control method for a touch display device including a display panel is provided. The display panel includes multiple first gate lines and multiple second gate lines respectively corresponding to a first field and a second field of a frame, and multiple sensing electrodes for touch sensing. Within one single frame period, the control method includes: scanning the first gate lines to update the first field; controlling the sensing electrodes to perform touch sensing and providing a first touch report; scanning the second gates lines to update the second field; and controlling the sensing electrodes to perform touch sensing and providing a second touch report. At least one of the first gates lines is located between two of the second gate lines, and at least one of the second gate lines is located between two of the first gate lines.

Description:
[0001]    This application claims the benefit of Taiwan application Serial No. 105103771, filed Feb. 4, 2016, the subject matter of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates in general to a touch display device, and more particularly to a touch display device capable of increasing a touch report rate and an associated control method. 
         [0004]    Description of the Related Art 
         [0005]    A touch display device is an image display device that includes an input device. The display device may be, for example, a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDD) or an electroluminescent display (ELD). A touch display device allows a user to input an instruction or message by touching or pressing a touch sensor on a screen through a finger or a stylus, while viewing an image displayed on the screen of the display device. 
         [0006]    A conventional touch display device is formed by additionally attaching a touch panel including touch sensors on a common display screen without a touch function. Such type of touch display device is generally referred to as an add-on type touch panel. Compared to a common display screen without a touch function, an add-on type touch panel usually suffers from issues of a larger thickness and poorer light transmittance. 
         [0007]    To overcome the issues above and to at the same time eliminate the additional manufacturing process of attaching a touch panel, an in-cell touch technology has been developed for a touch display device. For example, an in-cell touch panel directly places touch sensors into a display screen. In other words, when the manufacture of the display screen is complete, the touch sensors are simultaneously formed without involving the additional process of attaching a touch panel. 
         [0008]    For an in-cell touch screen, the time for updating data of all pixels thereon is referred to as one display frame period, and is usually defined by a cycle of a vertical synchronization signal. The reciprocal of the display frame period is generally referred to as a frame update rate, or simply frame rate. 
         [0009]    In an in-cell touch screen, some electrodes are required to handle dual functions of image display and touch sensing. Therefore, a time-division method is frequently adopted for these electrodes to sometimes control the function of image display and sometimes handle the function of touch sensing. One simplest is approach is that, after the data of all of the pixels is updated once and before the next display frame period begins, touch sensing is performed and a touch report is transmitted. A frequency of generating touch point information is usually referred to as a touch report rate. In a common in-cell touch screen, the touch report rate is equal to the frame rate. For example, if the frame rate is 60 Hz, the touch report rate of the common in-cell touch screen is also 60 Hz. 
         [0010]      FIG. 1  shows an LCD panel  10  and an associated control circuit, which together serve as an example of a touch display device. On the LCD panel  10 , a gate driver circuit  12 , gate lines G 1 , G 2 , . . . and G N , and data lines D 1 , D 2 , . . . and D M  are formed. The LCD panel  10  includes an active region  14 , in which a gate line and a data line  14  intersect to control a pixel. A data driving circuit  16  controls the data lines D 1 , D 2 , . . . and D M . A timing controller  18  provides a corresponding signal to the gate driver circuit  12  to cause the gate driver circuit  12  to sequentially scan the gate lines G 1 , G 2 , . . . and G N . The timing controller  18  also writes a digital signal into a register of the data driving circuit  16  according to an audio/video signal, and converts the digital signal to an analog data signal to drive the data lines D 1 , D 2 , . . . and D M . 
         [0011]      FIG. 1  further depicts an equivalent circuit in a pixel Cell nm  correspondingly controlled by the gate line G n  and the data line Dm. The pixel Cell nm  may be a pixel of any of the colors red, green and blue. The gate line G n  may turn on or turn off a thin-film transistor (TFT) TM nm . Through the turned on TFT TM nm , the data driving circuit  16  may store a data voltage V nm  in a capacitor C nm  of the pixel. A difference between a common voltage V COM  on a common electrode and a data voltage V nm  on a data electrode determines a twist level of the liquid crystals between the two electrodes, and thus determines a level of transmittance of light emitted from a backlight source (not shown) through the pixel Cell nm . 
         [0012]      FIG. 2  shows an operating timing applied to the touch display device in  FIG. 1 . The LCD panel  10  operates in a progressive scan mode. The gate lines G 1 , G 2 , . . . and G N  are scanned for display in a period  20 . The gate driver circuit  12  sequentially scan the gate lines G 1 , G 2 , . . . and G N . For example, the gate driving circuit  12  first pulls the gate line G 1  to a high voltage while keeping the other gate lines at a low voltage. As such, the TFT of all of the pixels connected to the gate line G 1  are all turned on. At this point, the data driving circuit  16  may write appropriate data voltages into all of the pixels connected to the gate line G 1  through the data lines D 1 , D 2 , . . . and D M , respectively. The gate driver circuit  12  then pulls the gate line G 1  down to a low voltage, and pulls the gate line G 2  to a high voltage, and the data driving circuit  16  writes appropriate data voltages into all of the pixels connected to the gate line G 2  through the data lines D 1 , D 2 , . . . and D M , respectively. Thus, in the period  20 , the data voltages of all of the pixels in  FIG. 1  are updated. An entire image formed by all of the pixels in  FIG. 1  is commonly referred to as a frame. In other words, one frame is updated in the period  20 . 
         [0013]    In a period  22 , touch detection and report are performed. After one frame is updated in the period  20 , touch detection and report may be performed using the data lines D 1 , D 2 , . . . and D M  or the common electrode in  FIG. 1  in the period  22  to provide one touch report. 
         [0014]    In periods  24  and  26 , the periods  20  and  22  are repeated. It should be noted that, as shown in  FIG. 2 , the periods  20  and  22  are completed in one frame period T FRAME , and the periods  24  and  26  are completed in a next frame period T FRAME . If the frame rate in  FIG. 2  is 60 Hz, the frame period T FRAME  in  FIG. 2  is 1/60 second, and the touch report rate, the same as the frame rate, is also 60 Hz. 
         [0015]    However, to provide a more sensitive and fast touch response, some software system manufacturers demand a touch report rate to be as high as 100 Hz. Therefore, there is a need for a solution for increasing the touch report rate. 
       SUMMARY OF THE INVENTION 
       [0016]    According to an embodiment of the present invention, a touch display device includes a display panel, a gate driver, a touch detection circuit and a timing controller. The display panel includes a plurality of first gate lines and a plurality of second gate lines. One least one of the first gates lines is located between two adjacent second gate lines, and at least one of the second gate lines is located between two adjacent first gate lines. The display panel includes a plurality of sensing electrodes for touch detection. The gate driver drives the first and second gate lines. The touch detection circuit is connected to the sensing electrodes, and provides a first touch report and a second touch report within in one single frame period. The timing controller controls the gate driver to scan the first gate lines and the second gate lines in a first period and a second period, respectively, within the one single frame period. The first touch report is between the first and second periods, and is provided by the touch detection circuit. 
         [0017]    According to another embodiment of the present invention, a control method for a touch display device is provided. The touch display device includes a display panel. The display panel includes a plurality of gate lines and a plurality of second gate lines corresponding to a first field and a second field of a frame, respectively, and a plurality of sensing electrodes for touch detection. Within one single frame period, the control method includes: scanning the first gate lines to update the first field at the display panel; controlling the sensing electrodes to perform touch detection and providing a first touch report; scanning the second gate lines to update the second field at the display panel; and controlling the sensing electrodes to perform touch sensing and providing a second touch report. At least one of the first gate lines is located between two of the second gate lines, and at least one of the second gate lines is located between two of the first gate lines. 
         [0018]    The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  (prior art) is an LCD panel and an associated control circuit jointly serving as an example of a touch display device; 
           [0020]      FIG. 2  (prior art) is an operating timing applied to the touch display device in  FIG. 1 ; 
           [0021]      FIG. 3  is a touch display device according to an embodiment of the present invention; 
           [0022]      FIG. 4  shows a touch integrated circuit and a common electrode plate located in an active region; 
           [0023]      FIG. 5  is an example of two gate driver circuits; 
           [0024]      FIG. 6  is a diagram of an operating timing applied to the touch display device in  FIG. 3 ; 
           [0025]      FIG. 7  shows signal timings of  FIG. 3 ; and 
           [0026]      FIG. 8  is an operating timing according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Throughout the disclosure, as anticipatable by one person skilled in the art based on the teaching of the disclosure, same denotations represent elements having identical or similar structures, functions and principles. To keep the disclosure concise and simple, details of elements with the same denotations are not repeatedly described. 
         [0028]      FIG. 3  shows a touch display device  30  according to an embodiment of the present invention. The touch display device  30  includes an LCD panel  31 , a data driving circuit  36 , a timing controller  38  and a touch integrated circuit  39 . 
         [0029]    Two gate driving circuits  32   l  and  32   r , gate lines G 1 , G 2 , . . . and G N , and data lines D 1 , D 2 , . . . and D M  are formed on the LCD panel  31 . The LCD panel  31  includes an active region  34 , in which one gate line intersects one data line to substantially control one pixel, as an example shown in  FIG. 1 . Parts in  FIG. 3  that are identical or similar to those in  FIG. 1  are omitted for brevity. In  FIG. 3 , the gate lines G 1 , G 2 , . . . and G N  are divided into two groups—a first group including odd-number gate lines G 1 , G 3 , . . . and G N-1 , and the other group including even-number gate lines G 2 , G 4 , . . . and G N . The gate line G 2  is between the gate lines G 1  and G 3 , and the gate line G 3  is between the gate lines G 2  and G 4 . In the embodiment in  FIG. 3 , assume that N is an even number. The gate driving circuits  32   l  and  32   r  collectively form a gate driver that controls all of the gate lines G 1 , G 2 , . . . and G N . The gate driving circuits  32   l  and  32   r  are located outside the active region  34 , and are near left and right sides of the active region  34 , respectively. The gate driving circuit  32   l  may drive the odd-number gate lines but not the even-number gate lines, and the gate driving circuit  32   r  may drive the even-number gate lines but not the odd-number gate lines. 
         [0030]    The data driving circuit  36  controls the data lines D 1 , D 2 , . . . and D M . The timing controller  38  provides corresponding signals to the gate driving circuits  32   l  and  32   r  and controls the data driving circuit  3 . Associate details of the operating timing are to be described shortly. 
         [0031]      FIG. 4  shows an example of the touch integrated circuit  39  and common electrode plates  37  located in the active region  34  for explaining the touch detection performed by the touch display device  30 . Each of the common electrode plates  37  corresponds to one or multiple pixels to serve as a sensing electrode. The touch integrated circuit  38  serves as a touch detection circuit, and may sequentially measure self capacitance changes of the common electrode plates  37  to determine whether a touch point occurs and a position of the touch point to perform touch report. The LCD panel  31  is a capacitive touch panel. In one embodiment, the touch integrated circuit  39  may sequentially measure individual self capacitance changes of the common electrode plates  37  on one entire row one row after another to perform touch detection and report. When the pixels on the LCD panel  31  are being updated, the touch integrated circuit  39  provides the common voltage V COM  in a constant value to all of the common electrode plates  37 , and so the touch display device  30  cannot simultaneously perform touch detection and report. The present invention is not limited to the structure shown in  FIG. 4 . It should be noted that, the structure in  FIG. 4  is an example for explaining one type of structure used for touch detection, and how touch detection and report cannot be simultaneously performed with updating the pixels. 
         [0032]      FIG. 5  shows an example of the gate driving circuits  32   l  and  32   r , each being a shift register. The timing controller  38  provides a clock signal CLK and a starting pulse SP ODD  to the gate driving circuit  32   l , but provides the clock signal CLK and a starting pulse SP EVEN  to the gate driving circuit  32   r . Time points at which the starting pulse SP ODD  and the starting pulse SP EVEN  occur are determined by the timing controller  38 . The starting pulse SP ODD  first shifts to the gate line G 1 , the gate line G 3 , the gate line G 5 , and so on, and eventually leaves the gate line G N-1  as the clock signal CLK switches. Similarly, starting from the gate line G 2 , the starting pulse SP EVEN  gradually shifts to the gate line G N  and eventually leaves the gate line G N  as the clock signal CLK switches. The gate driving circuits  32   l  and  32   r  may be integrated in the LCD panel  31 . For example, the switches in the gate driving circuits  32   l  and  32   r  may be formed by TFTs identical or similar to the TFT TM nm  in the pixels. 
         [0033]      FIG. 6  shows an operating timing applied to the touch display device  30  in  FIG. 3 , and  FIG. 7  shows signal timings of  FIG. 3 . In this embodiment, the touch display device  30  operates in an interlaced scan mode. 
         [0034]    The gate lines G 1 , G 3 , . . . and G N-1  are scanned for display in a period  40 , which is completed in a period T odd  in  FIG. 7 . As shown in  FIG. 3 , the timing controller  38  initially provides the starting pulse SP ODD . As the clock signal CLK switches, the gate driving circuit  32   l  sequentially scan the gate lines G 1 , G 3 , . . . and G N-1 . Meanwhile, the gate driving circuit  32   r  keeps the voltages on all of the even-number gate lines (the gate lines G 2 , G 4 , . . . and G N ) unchanged. The data driving circuit  36  may write appropriate data voltages into all of the pixels of the odd-number gate lines through the data lines D 1 , D 2 , . . . and D M . Each of the common electrode plates  37  is provided with the fixed common voltage V COM  by the touch integrated circuit  39  at this point. Throughout the specification, an image formed by all of the pixels of the odd-number gate lines is referred to as an odd field; an image formed by of the pixels of the even-number gate lines is referred to as an even field. One odd field and one even field form one frame. In brief, the odd field is updated in the period  40 . 
         [0035]    Touch detection and report are performed in a period  42 , which is completed in a period T tr1  in  FIG. 7 . After the odd field is updated in the period  40 , touch detection and report may be performed using the common electrode plates  37  in  FIG. 4  in the period  42 . For example, the voltages on the common electrode plates  37  are sequentially changed to measure the individual self capacitance changes of the common electrode plates  37 , so as to determine whether a touch point occurs and a position of the touch point. A first touch report is provided in the period  42 . 
         [0036]    The gate lines G 2 , G 4 , . . . and G N  a in a period  44 , which is completed in a period T even  in  FIG. 7 . As shown in  FIG. 7 , the timing controller  38  initially provides the starting pulse SP EVEN . As the clock signal CLK switches, the gate driving circuit  32   r  sequentially scans the gate lines G 2 , G 4 , . . . and G N . Meanwhile, the gate driving circuit  32   l  keeps the voltages on all of the odd-number gate lines (G 1 , G 3 , . . . and G N-1 ) unchanged. The data driving circuit  36  may write appropriate data voltages into all of the pixels of the even-number gate lines through the data lines D 1 , D 2 , . . . and D M . Similarly, each of the common electrode plates  37  is provided with the constant common voltage V COM  by the touch integrated circuit  39 . In brief, the even field is updated in the period  44 . 
         [0037]    Touch detection and report are performed in a period  46 , which is completed in a period T tr2  in  FIG. 7 . A second touch report is provided in the period  46 , and associated details may be identical or similar to those in the period  42 . 
         [0038]    As shown in  FIG. 6 , the odd field is updated in the period  40 , and the even field is updated in the period  44 . Thus, in one frame period T FRAME , one entire frame is updated. 
         [0039]    The periods  40 ,  42 ,  44  and  46  are repeated in the periods  48 ,  50 ,  52  and  54 , respectively. As shown in  FIG. 6 , the periods  40 ,  42 ,  44  and  46  are completed in one frame period T FRAME , and the periods  48 ,  50 ,  52  and  54  are completed in the next frame period T FRAME . In  FIG. 6 , there are two touch reports in one frame period T FRAME . If the frame rate in  FIG. 6  is 60 Hz, the touch report rate in  FIG. 6  is 120 Hz, which is twice the frame rate. 
         [0040]    The present invention does not limit the touch report rate to be twice the frame rate, and the touch report rate may also be three or more times the frame rate. For example, the gate lines G 1 , G 2 , G 3  . . . are divided into three groups—a first group including the gate lines G 1 , G 4  . . . , a second group including the gate lines G 2 , G 5  . . . , and a third group including the gate lines G 3 , G 6  . . . . A first field is an image displayed by the pixels in the first group, a second field is an image displayed by the pixels in the second group, and a third field is an image displayed by the pixels in the third group. The first, second and third fields together from one frame.  FIG. 8  shows an operating timing implemented according to the present invention. In one frame period T FRAME , the first, second and third fields are sequentially updated. The touch detection and report are performed once each time a field is updated. Thus, if the frame rate in  FIG. 8  is 60 Hz, the touch report rate in  FIG. 6  is 180 Hz, which is three times the frame rate. 
         [0041]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.