Patent Publication Number: US-9886892-B2

Title: Gate driving circuit, gate driving method, and display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a Section 371 National Stage Application of International Application No. PCT/CN2015/076736, filed on 16 Apr. 2015, entitled “GATE DRIVING CIRCUIT, GATE DRIVING METHOD, AND DISPLAY APPARATUS”, which has not yet published, which claims priority to Chinese Application No. 201410584227.5, filed on 27 Oct. 2014, incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technology, and more particularly, to a gate driving circuit, a gate driving method, and a display apparatus. 
     BACKGROUND 
     An amorphous silicon bottom gate type Thin Film Transistor (TFT), as a switch element, is primarily characterized in that there is a jump voltage (ΔVp) at a switching instant, and when different voltages are applied to the TFT, the generated jump voltages ΔVp are also different. In a flicker pattern, such jump voltage may results in a problem that an image flickers seriously. 
     In view of the above problem, a low order voltage (the low order voltage and a high order voltage commonly form a multi-order gate voltage MLG) is generally provided before gate off to reduce ΔVp, thereby improving the flicker phenomenon. The longer the low order voltage is applied, the more obvious the effect of overcoming the flicker phenomenon is. However, in a high resolution display apparatus, the charging time for each pixel in one frame is relatively short. As a result, if the low order voltage is applied for a long time, the charging rate for the pixel is not sufficient, which will influence the display quality. If the low order voltage is applied for a short time, the effect of overcoming the flicker phenomenon is not sufficiently obvious, i.e., the flicker phenomenon due to ΔVp cannot be effectively avoided. 
     SUMMARY 
     Therefore, embodiments of the present disclosure provide a gate driving circuit and a gate driving method which can not only avoid image flicker but also can avoid V-Block. 
     According to an aspect of the present disclosure, a gate driving circuit is provided, comprising: a driving control unit and a gate signal generation unit, wherein the driving control unit is configured to generate different driving control signals suitable for different display patterns; and the gate signal generation unit is connected to the driving control unit and is configured to generate a multi-order gate voltage in response to the driving control signal generated by the driving control unit, wherein duration of a low order voltage included in the generated multi-order gate voltage corresponds to the respective display pattern. 
     In an implementation of the present disclosure, the driving control unit comprises: a timing controller and multiple controlled switch unit, wherein the timing controller has multiple pulse signal output ends suitable for generating multiple pulse signals and is configured to output pulse signals with different widths through different pulse signal output ends, wherein a pulse signal is suitable for a display pattern; and each of the controlled switch units is arranged between a pulse signal output end of the timing controller and a driving control signal input end of the gate signal generation unit, and various controlled switch units are connected to different pulse signal output ends, 
     wherein the multi-order gate voltage is generated by the gate signal generation unit in response to the pulse signal, and comprises a low order voltage in duration consistent with a width of the pulse signal. 
     In an implementation of the present disclosure, the various controlled switch units are transistors having first electrodes respectively connected to pulse signal output ends of the timing controller and second electrodes respectively connected to driving control signal input ends of the gate signal generation unit. 
     In an implementation of the present disclosure, the driving control unit further comprises a controller connected to a control end of each controlled switch unit, and configured to control turn-on/turn-off of the respective controlled switch unit in response to the detected display pattern. 
     In an implementation of the present disclosure, the timing controller is suitable for generating three pulse signals with different widths suitable for a normal pattern, a flicker pattern, and a gray level display pattern respectively. 
     According to another aspect of the present disclosure, a gate driving method is provided, comprising: 
     generating a driving control signal corresponding to a current display pattern according to the current display pattern; and generating, by a gate signal generation unit, a multi-order gate voltage according to the driving control signal, wherein duration of a low order voltage included in the generated multi-order gate voltage corresponds to the respective display pattern. 
     In an implementation of the present disclosure, in a flicker pattern, the gate signal generation unit generates a multi-order gate voltage having a low order voltage in first duration; in a normal display pattern, the gate signal generation unit generates a multi-order gate voltage having a low order voltage in second duration; and in a gray level display pattern, the gate signal generation unit generates a multi-order gate voltage having a low order voltage in third duration, wherein the first duration is larger than the second duration and the second duration is larger than the third duration. 
     According to another aspect of the present disclosure, a display apparatus is provided, comprising the gate driving circuit described in any of the above embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a structural diagram of a gate driving circuit according to an embodiment of the present disclosure; 
         FIG. 2  illustrates a structural diagram of a driving control unit in  FIG. 1 ; and 
         FIG. 3  illustrates a timing diagram of a part of signals in a gate driving circuit according to an embodiment of the present application. 
         FIG. 4A  illustrates illustrations of the gray level display pattern and  FIG. 4B  illustrates illustrations of the flicker pattern. 
     
    
    
     DETAILED DESCRIPTION 
     Detailed description of the present disclosure will be further described below in conjunction with accompanying drawings and embodiments. The following embodiments are merely used to illustrate the technical solutions of the present disclosure more clearly, instead of limiting the protection scope of the present disclosure. 
     The embodiments of the present disclosure provide a gate driving circuit. As shown in  FIG. 1 , the gate driving circuit comprises a driving control unit  10  configured to generate a driving control signal corresponding to a respective display pattern; and a gate signal generation unit  20  connected to the driving control unit  10  and configured to generate a multi-order gate voltage in response to the driving control signal generated by the driving control unit  10 , wherein duration of a low order voltage included in the generated multi-order gate voltage corresponds to the respective display pattern. 
     Those skilled in the art should understand that in the embodiments of the present disclosure, as the driving control unit can generate a corresponding driving control signal in a respective display pattern, the driving signal generation unit can determine a current display pattern according to a current input driving control signal, and generate a multi-order gate voltage having a low order voltage in duration corresponding to the respective display pattern. In a specific implementation, duration of a low order voltage in a particular display pattern may be set according to the requirements of those skilled in the art. In order to achieve a better display effect, the terms “corresponding” means that the low order gate voltage in the respective multi-order gate voltage can avoid the display problem generated in the display pattern. 
     It should be understood that the terms “low order voltage” in the embodiments of the present disclosure refer to a voltage with a smaller absolute value in the multi-order gate voltage. Specifically, for an active-high gate voltage, the low order voltage should be lower than the high level voltage, and for an active-low gate voltage, an absolute value of the low order voltage should be lower than an absolute value of the low level signal. 
     The gate driving circuit according to the present disclosure can achieve driving for display by using a multi-order gate voltage having a low order voltage in long duration when the display pattern of the display apparatus is a flicker pattern, so as to eliminate the undesirable phenomenon that an image flickers, and achieve driving for display by using a multi-order gate voltage having a low order voltage in short duration when the display pattern is a gray level display pattern, so as to avoid V-Block, thereby improving the quality of the image display. Even if the whole effective gate voltage signal has short duration, the gate driving circuit according to the embodiments of the present disclosure can also prevent the V-Block phenomenon while avoiding the image from flickering. The effect of avoiding the image from flickering is more obvious especially in a high PPI display apparatus. 
     Specifically, the gate signal generation unit here may be a conventional driver Integrated Circuit (Driver-IC). The following description is given by taking the gate signal generation unit being a Driver-IC as an example. The Driver-IC is used to generate a gate voltage signal required for driving a gate. In practical applications, various effective gate voltage signals for driving and controlling have the same duration. 
     In an alternative implementation, as shown in  FIG. 2 , the driving control unit  20  in  FIG. 1  may specifically comprise: 
     a timing controller TCON and three controlled switch units T 1 , T 2  and T 3 . The TCON has at least three pulse signal output ends OE 1 , OE 2  and OE 3 , which can generate three pulse signals with different widths, and output the pulse signals through respective pulse signal output ends, wherein the three pulse signals with different widths correspond to a display pattern, a flicker pattern, and a gray level display pattern respectively. A first end of the first controlled switch unit T 1  is connected to OE 1 , a first end of the second controlled switch unit is connected to OE 2 , and a first end of the third switch unit is connected to OE 3 . Second ends of various controlled switch units are connected to driving control signal input ends of the Driver-IC. Generally, the low order voltage has the longest duration in the flicker pattern, has smaller duration in the normal pattern than the flicker pattern, and has the smallest duration in the gray level display pattern. 
     In this case, the pulse signals become the driving control signal. The Driver-IC generates respective multi-order gate voltages in response to the pulse signals with different duration. 
     More specifically, the Driver-IC may generate a multi-order gate voltage in response to a pulse signal, wherein the multi-order gate voltage comprises a low order voltage in duration consistent with a width of the pulse signal. 
     In practical applications, a particular controlled switch unit may be controlled to turn on at the right time by applying suitable control signals to the control ends of various controlled switch units, so that the Driver-IC generates a suitable multi-order gate voltage, thereby improving the image quality. 
     In a specific implementation, as shown in  FIG. 2 , the TCON further comprises a clock signal output end for outputting a clock signal STV to achieve image synchronization. 
     It should be noted that although  FIG. 2  illustrates a condition that the TCON generates three pulse signals with different widths and outputs the pulse signals through three pulse signal output ends, in practical applications, the TCON may also only generate two pulse signals with different widths and output the pulse signals through two pulse signal output ends, which can also avoid the problems of flicker and V-Block at the same time. The same problem can also be solved by generating more than three pulse signals with different widths and providing more than three output ends. However, such scheme may have a relatively complex design. Such configuration in the embodiments of the present disclosure has an advantage of providing a multi-order gate voltage corresponding to a normal display pattern, to achieve a better display effect and a relatively simple design. 
     The driving control unit illustrated in  FIG. 2  has features of a simple structure and ease of control. However, in practical applications, the functions of the driving control unit may also be achieved by other structures. That is, the structure in  FIG. 2  should not be construed as limiting the protection scope of the present disclosure. 
     Further, as shown in  FIG. 2 , various controlled units T 1 , T 2  and T 3  according to the embodiments of the present disclosure are transistors. T 1 , T 2  and T 3  have first electrodes respectively connected to the pulse signal output ends OE 1 -OE 3  of the TCON, and second electrodes respectively connected to the driving control signal input ends of the Driver IC. Of course, in practical applications, other switch units which can be turned on or turned off according to the control signal may also be selected. 
     Generally, the width of the pulse signal finally determines the duration of the low order voltage in the multi-order gate voltage. As shown in  FIG. 3 , when T 1  is turned on, OE 1  inputs a pulse signal with a width of t 1  to the Driver-IC. In this case, the duration of the low order voltage in the multi-order gate voltage MLG 1  generated by the Driver-IC is also t 1 . Correspondingly, when T 2  is turned on, OE 2  inputs a pulse signal with a width of t 2  to the Driver-IC. In this case, the duration of the low order voltage in the multi-order gate voltage MLG 2  generated by the Driver-IC is also t 2 . When T 3  is turned on, OE 3  inputs a pulse signal with a width of t 3  to the Driver-IC. In this case, the duration of the low order voltage in the multi-order gate voltage MLG 3  generated by the Driver-IC is also t 3 . Further, it can be seen from the figure that the total duration of various effective multi-order gate voltages MLG 1 , MLG 2  and MLG 3  should be consistent, and have the same starting position as that of the STV. 
     Further, as shown in  FIG. 2 , the driving control unit according to the embodiments of the present disclosure further comprises a controller MCU, which is connected to control ends (gates) of various controlled switch units and controls turn-on/turn-off of respective controlled switch units according to the detected display type. 
       FIG. 4A  illustrates illustrations of the gray level display pattern and  FIG. 4B  illustrates illustrations of the flicker pattern. 
     In a specific implementation, the controller here may be a main controller MCU of the whole display apparatus, which controls the light-emitting and display of the whole display apparatus, and can acquire the display pattern of the next frame before the next frame is displayed. In this case, the main controller controls turn-on/turn-off of various switch units according to the display pattern of the next frame. 
     The embodiments of the present disclosure further provide a gate driving method, comprising: 
     generating a driving control signal corresponding to a current display pattern according to the current display pattern, and generating, by a gate signal generation unit, a multi-order gate voltage according to the driving control signal, wherein duration of a low order voltage included in the generated multi-order gate voltage corresponds to the respective display pattern. 
     According to the embodiments of the present disclosure, in a flicker pattern, a multi-order gate voltage having a low order voltage in long duration is applied, which can better prohibit a jump voltage of the switch TFT and reduce the flicker degree. In a gray level display pattern, a multi-order gate voltage having a low order voltage in short duration is applied, which can better improve the charging rate and avoid the phenomenon of V-Block. In a normal display pattern, the duration of the low order voltage in the applied multi-order gate voltage is between the long duration and the short duration described above, which achieves moderate charging time for a capacitor, and is beneficial for improving the image quality. For example, in a case that the multi-order voltage is a two-order voltage, the low order voltage may have a value equal to 30%-60% of a normal driving voltage, and have duration which occupies 5%-50% of the duration of the whole multi-order voltage. 
     The gate driving method according to the embodiments of the present disclosure may be achieved by the above gate driving circuit. 
     The embodiments of the present disclosure further provide a display apparatus, comprising the gate driving circuit described in any of the above embodiments. 
     The display apparatus here may be any product or component having a display function such as an electronic paper, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator or the like. 
     The above description is merely preferable embodiments of the present disclosure. It should be noted that a number of improvements and variations can further be made by those skilled in the art without departing from the technical principle of the present disclosure, and all of these improvements and variations should also be construed as falling within the protection scope of the present disclosure.