Patent Publication Number: US-11657776-B2

Title: Driving method and drive circuit of display panel

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
     This application claims the priority to the Chinese Patent Application No. CN201811465418.4, filed with National Intellectual Property Administration, PRC on Monday, Dec. 3, 2018 and entitled “DRIVING METHOD AND DRIVE CIRCUIT OF DISPLAY PANEL”, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present application relates to the technical field of display, especially a driving method and a drive circuit of a display panel. 
     BACKGROUND 
     The statements herein merely provide background information related to the present application and do not necessarily constitute the conventional art. 
     With the development and advancement of science and technology, Liquid Crystal Display (LCD) has become the mainstream of display products due to its thin body, low power consumption and low radiation, and has been widely used. Most of the liquid crystal displays on the market are backlight liquid crystal displays, which include liquid crystal panels and backlight modules. The working principle of liquid crystal panels is to place liquid crystal molecules in two parallel glass substrates and apply driving voltage on the two glass substrates to control the rotation direction of the liquid crystal molecules, so as to refract the light of the backlight modules to generate a picture. 
     Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has been playing a leading role in the display field because of its low power consumption, excellent picture quality and high yield. Likewise, the thin film transistor liquid crystal display includes a liquid crystal panel and a backlight module, the liquid crystal panel includes a color filter substrate (which is also called color filter substrate), thin film transistor substrate and mask, and the above substrate includes a transparent electrode on the opposite inner side. A layer of Liquid Crystal (LC) molecules are sandwiched between the two substrates. 
     With the increasing size and resolution of LCD TV, the difference will be minimized by two-sided drive of data line, but this method will bring great difficulty to the production line, and at the same time, it will double the data lines, resulting in a significant increase in manufacturing costs. 
     SUMMARY 
     The purpose of the present application is to provide a driving method and a drive circuit of a display panel, so as to solve the poor display effect of the display panel. 
     To achieve the above objective, the present application discloses a driving method of a display panel. 
     A driving method of a display panel, including: 
     according to the distance from the data driving chip, the display panel is divided into a plurality of charging regions in advance, each charging area is provided with a unique digital code, and the corresponding information of the charging area and the digital code is stored in the timing control chip in advance; 
     detecting a charging area where the pixel to be charged is located, and outputting a corresponding digital code according to the charging area by a timing control chip: 
     the gamma chip receives the digital code and generates a gamma voltage corresponding to the digital code according to the input operating voltage to drive charging operation of the charging area corresponding to the digital code. 
     Optionally, the display panel further includes an operating voltage circuit that generates the operating voltage; the gamma chip includes a reference voltage generation circuit and a gamma voltage generation circuit; the input terminal of the reference voltage generation circuit is coupled to the timing control chip and the operating voltage circuit respectively, and the input terminal of the gamma voltage generation circuit is coupled to the reference voltage generation circuit. 
     Optionally, the step that the gamma chip receives the digital code and generates a gamma voltage corresponding to the digital code according to the input operating voltage to drive charging operation of the charging area corresponding to the digital code includes: 
     the reference voltage generation circuit receives the digital code and generates a reference voltage corresponding to the digital code according to the input operating voltage. 
     Optionally, the step that the reference voltage generation circuit receives the digital code and generates a reference voltage corresponding to the digital code according to the input operating voltage includes: 
     the gamma voltage generation circuit receives a reference voltage and generates a gamma voltage corresponding to the digital code to drive charging operation of the charging area corresponding to the digital code. 
     Optionally, the step that the gamma voltage generation circuit receives a reference voltage and generates a gamma voltage corresponding to the digital code to drive charging operation of the charging area corresponding to the digital code includes: 
     the reference voltage generation circuit receives the digital code and multiplies the working voltage by the digital voltage to obtain the reference voltage. 
     Optionally, the step that the reference voltage generation circuit receives the digital code and multiplies the working voltage by the digital voltage to obtain the reference voltage includes: 
     the gamma voltage generation circuit receives the digital code and generates a gamma voltage corresponding to the digital code according to the reference voltage. 
     Optionally, the gamma chip further includes a gamma voltage division coefficient memory storing gamma voltage division coefficients; 
     the step that the gamma voltage generation circuit receives a reference voltage and generates a gamma voltage corresponding to the digital code to drive charging operation of the charging area corresponding to the digital code includes: 
     the gamma voltage generation circuit receives a reference voltage and generates a corresponding gamma voltage according to the corresponding gamma voltage division coefficient to drive charging operation of the charging area corresponding to the digital code. 
     Optionally, the first side and the second side of the display panel are provided with a data driving chip, which adopts a data line double-sided driving mode; 
     or only the first side or the second side of the display panel is provided with a data driving chip, which adopts a data line single-sided driving mode. 
     Optionally, the farther the charging area is away from the data driving chip, the larger the corresponding gamma voltage is. 
     Optionally, the display area of the display panel is sequentially divided into a plurality of charging areas according to the number of rows of data lines, and each charging area has a unique digital code. 
     Optionally, the step of detecting a charging area where the pixel to be charged is located, and outputting a corresponding digital code according to the charging area by a timing control chip includes: 
     The number of rows of counting data lines of the counter of the timing control chip; 
     optionally, the step that the number of rows of counting data lines of the counter of the timing control chip includes: 
     the timing control chip identifies the count value of the counter, and obtains and outputs the corresponding digital code from the memory. 
     Optionally, if the count value of the counter is greater than or equal to 100 and less than or equal to 200, a digital code 2 corresponding to 1.2 times standard gamma voltage is obtained. 
     Optionally, if the count value of the counter X is greater than or equal to 200 and less than or equal to 300, a numeric code 3 corresponding to 1.3 times standard gamma voltage is obtained. 
     Optionally, if the count value of the counter X is greater than or equal to 300 and less than or equal to 400, a numeric code 4 corresponding to 1.4 times standard gamma voltage is obtained. 
     The present application also discloses a driving method of a display panel, including: 
     According to the distance from the data driving chip, the display panel is divided into a plurality of charging areas in advance according to the number of rows of data lines, each charging area has a unique digital code, and the corresponding information of the charging area and the digital code is stored in the timing control chip in advance; 
     the number of rows of counting data lines of the counter of the timing control chip; 
     the timing control chip identifies the count value of the counter, and obtains and outputs the corresponding digital code from the memory; 
     the reference voltage generation circuit receives the digital code and generates a reference voltage corresponding to the digital code according to the input operating voltage of the operating voltage circuit; 
     the gamma voltage generation circuit receives a reference voltage and generates a corresponding gamma voltage according to the corresponding gamma voltage division coefficient to drive charging operation of the charging area corresponding to the digital code; 
     the farther the charging area is from the data driving chip, the larger the corresponding gamma voltage is. 
     The present application also discloses a driving circuit of a display panel, using the above driving method, which includes: 
     according to the distance from the data driving chip, the display panel is divided into a plurality of charging regions in advance, each charging area is provided with a unique digital code, and the corresponding information of the charging area and the digital code is stored in the timing control chip in advance; 
     detecting a charging area where the pixel to be charged is located, and outputting a corresponding digital code according to the charging area by a timing control chip; 
     the gamma chip receives the digital code and generates a gamma voltage corresponding to the digital code according to the input operating voltage to drive charging operation of the charging area corresponding to the digital code. 
     In the present application, the gamma voltage can be adjusted according to the charging difference of the charging area, and the darker charging area is given an actual gamma voltage higher than the standard gamma voltage, so that the lightness of the corresponding charging area is enhanced and the lightness difference with other areas is reduced or even eliminated. Further, the present application realizes the generation of different gamma voltages to different charging areas by supplying different reference voltages to the gamma voltage generation circuit; based on different reference voltages, the gamma voltage generation circuit generates different gamma circuits through the same circuit, thereby avoiding circuit changes caused by changing the structure of the gamma voltage generation circuit and upgrading the production line caused by circuit changes, so as to avoid an increase in generation cost. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are included to provide an understanding of embodiments of the present application and constitute a part of the specification, illustrate embodiments of the application and, together with the text description, explain the principles of the application. Obviously, the drawings in the following description are merely some embodiments of the present application, and those skilled in the art can obtain other drawings according to the drawings without any inventive labor. In the drawings: 
         FIG.  1    is a schematic diagram of a driving method flow of a display panel in an embodiment of the present application: 
         FIG.  2    is a specific schematic diagram of a driving method flow of a display panel in an embodiment of the present application; 
         FIG.  3    is a structural schematic diagram of a display panel in an embodiment of the present application; 
         FIG.  4    is a schematic diagram of a drive circuit of a display panel in an embodiment of the present application. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The specific structural and functional details disclosed herein are merely representative and are illustrative of the exemplary embodiments of the present application. However, the present application may be embodied in many alternative forms and should not be construed as being limited only to the embodiments set forth herein. 
     In the description of the present application, it should be understood that, the terms “center”, “horizontally”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like for indicating an orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are intended solely to facilitate description and simplification of the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus is not to be construed as limiting the present application. Further, the terms “first” and “second” are only for the purpose of description and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as “first,” and “second,” may explicitly or implicitly include one or more of the features. In the description of the present application, “multiple” means two or more unless otherwise noted. In addition, the term “including” and any variations thereof are intended to cover non-exclusive inclusion. 
     In the description of the present application, it should be noted that, unless expressly specified and defined otherwise, the terms “mount”, “attach” and “connect” are to be understood broadly, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be an either mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and can be an internal connection between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances. 
     The terms used herein are merely intended to describe specific embodiments and are not intended to limit the exemplary embodiments. Unless clearly indicated by the context otherwise, the singular forms “a” or “an” are intended to include the plural. It should also be understood that the terms “include” and/or “comprise” as used herein specify the presence of the features, integers, steps, operations, units and/or components set forth without excluding the presence or addition of one or more other features, integers, steps, operations, units, components and/or combinations thereof. 
     The present application will now be described by reference to the accompanying drawings and alternative embodiments. 
     As shown in  FIGS.  1  to  4   , the embodiment of the present application discloses a driving method of a display panel  100 , including: 
     S 10 : according to the distance from the data driving chip  140 , the display panel  100  being divided into a plurality of charging regions in advance, each charging area being provided with a unique digital code, and the corresponding information of the charging area and the digital code being stored in the timing control chip  110  in advance; 
     S 11 : detecting a charging area where the pixel to be charged is located, and outputting a corresponding digital code according to the charging area by a timing control chip  110 ; 
     S 12 : the gamma chip  120  receiving the digital code and generating a gamma voltage corresponding to the digital code according to the input operating voltage to drive charging operation of the charging area corresponding to the digital code. 
     As the size and resolution of the liquid crystal television become larger and higher, the charging difference between the proximal end and the distal end of the data line from the data driving chip  140  becomes more and more obvious when the data line charges the panel, lying in that the charging effect of the distal end is poor and the lightness is low, and the charging effect of the proximal end is good and the lightness is high. In the present scheme, the gamma voltage can be adjusted according to the charging difference of the charging area, and the darker charging area is given an actual gamma voltage higher than the standard gamma voltage, so that the lightness of the corresponding charging area is enhanced and the lightness difference with other areas is reduced or even eliminated. Further, the present scheme realizes the generation of different gamma voltages to different charging areas by supplying different reference voltages to the gamma voltage generation circuit  122 ; based on different reference voltages, the gamma voltage generation circuit  122  generates different gamma voltages through the same circuit, thereby avoiding circuit changes caused by changing the structure of the gamma voltage generation circuit  122  and upgrading the production line caused by circuit changes, so as to avoid an increase in generation cost. 
     In one or more embodiments, the display panel  100  further includes an operating voltage circuit  130  that generates the operating voltage; the gamma chip  120  includes a reference voltage generation circuit  121  and a gamma voltage generation circuit  122 ; the input terminal of the reference voltage generation circuit  121  is coupled to the timing control chip  110  and the operating voltage circuit  130  respectively, and the input terminal of the gamma voltage generation circuit  122  is coupled to the reference voltage generation circuit  121 ; 
     the step that the gamma chip  120  receives the digital code and generates a gamma voltage corresponding to the digital code according to the input operating voltage to drive charging operation of the charging area corresponding to the digital code includes: 
     the reference voltage generation circuit  121  receives the digital code and generates a reference voltage corresponding to the digital code according to the input operating voltage; 
     the gamma voltage generation circuit  122  receives a reference voltage and generates a gamma voltage corresponding to the digital code to drive charging operation of the charging area corresponding to the digital code. 
     In the present application, the reference voltage generation circuit  121  converts the input operating voltage into a reference voltage; the gamma voltage generate circuit  122  drives a gamma voltage output from a reference voltage; then, the reference voltage is also used as the reference voltage of the gamma voltage generation circuit  122 , and all the gamma voltages are obtained by dividing the reference voltages, so that the magnitude of the reference voltage is changed, and different magnitudes of the gamma voltages are obtained. This method is simple and easy to operate, without changing or adding other devices, and reduces the difficulty of production. 
     In one or more embodiments, the reference voltage generation circuit  121  receives the digital code and multiplies the working voltage by the digital voltage to obtain the reference voltage; 
     the gamma voltage generation circuit  122  receives the digital code and generates a gamma voltage corresponding to the digital code according to the reference voltage. 
     In the present application, the gamma voltage is obtained by dividing the reference voltage. Now we can amplify the operating voltage that produces the reference voltage. Then, a reference voltage larger than the original can be obtained, so that a gamma voltage larger than the original can be obtained to compensate the voltage of the charging area, so that the lightness of the charging area with darker lightness can be improved, and the lightness and darkness phenomenon between the proximal end and the distal end of the data line can be reduced or even be eliminated. 
     The digital encode can be determined according to actual requirements and the lightness difference of the display panel. For example, when the reference voltage is obtained by voltage division, the digital code can be made smaller than or equal to 0, but the charging area farther from the data driving chip has the larger gamma voltage, and the corresponding digital code is larger. 
     In an embodiment, the gamma chip  120  further includes a gamma voltage division coefficient memory  123  storing gamma voltage division coefficients; 
     the step that the gamma voltage generation circuit  122  receives a reference voltage and generates a gamma voltage corresponding to the digital code to drive charging operation of the charging area corresponding to the digital code includes: 
     the gamma voltage generation circuit  122  receives a reference voltage and generates a corresponding gamma voltage according to the corresponding gamma voltage division coefficient to drive charging operation of the charging area corresponding to the digital code. 
     In this scheme, according to different gamma voltage division coefficients, different magnitudes of gamma voltage division are performed to obtain corresponding digital code and gamma voltage under lightness requirements, and under the same other conditions, if the charging area is farther away from the data driving chip, the corresponding gamma voltage is larger. The gamma voltage division coefficient memory  123  stores a large number of gamma voltage division coefficients, which can be provided at the gamma chip to reduce the pressure of cross-board data transmission. 
     In one or more embodiments, the first side and the second side of the display panel  100  are provided with a data driving chip  140 , which adopts a data line double-sided driving mode: 
     or only the first side or the second side of the display panel  100  is provided with a data driving chip  140 , which adopts a data line single-sided driving mode. 
     The scheme can be applied to the data line unilateral drive architecture, so that the technical difficulty caused by the double-side drive mode of the data line and the production difficulty caused by the double-side drive mode of the data line can be avoided, and the increase of the manufacturing cost and the space occupation can be avoided; it is also possible to use a data line with double-sided driving architecture; in the double-sided driving architecture, the pixel is located at the farther place of the two-side data driving chip  140 , and the lightness of the pixel is still dark. By using the method of the present application, the phenomenon can be avoided, and the number and difficulty of dividing the charging areas can be reduced by adopting the data line double-sided driving architecture, and the computational difficulty and the demand of the gamma circuit can be reduced. When the data driving chip is set on one side, the gamma voltage at the far end of the data line is larger. When the data driving chips are set on both sides, the gamma voltage of the charging area corresponding to the middle of the data line is the largest. 
     Of course, taking the display panel as an example, with the viewer as the center, the first side is an upper side of the display panel, and the second side is the lower side of the display panel; in addition, those skilled in the art may set the first side as the lower side of the display panel and the second side as the upper side of the display panel as needed. 
     In an embodiment, the farther the charging area is away from the data driving chip  140 , the larger the corresponding gamma voltage is. 
     In the scheme, if the charging area is farther from the data driving chip  140 , the standard gamma voltage loss generated by the data driving chip  140  is greater due to the increase in the distance of the resistance of the charging area, and thus the lightness of the charging area is darker as the charging area is farther from the data driving chip  140 ; an actual gamma voltage with a greater difference than the standard gamma low voltage is applied, so that more voltage compensation can be obtained for a charging area farther from the data driving chip  140  and having a high loss, and less voltage compensation can be obtained for a charging area farther from the data driving chip  140  and having a low loss. In this way, the lightness difference between the charging areas can be reduced and even be eliminated. In other words, if the difference from the standard gamma voltage is larger, that is, the gamma voltage in the charging area closest to the data driving chip  140  corresponds to the standard gamma voltage; in order to cancel the loss of the gamma voltage, when the farther charging area has a larger gamma voltage, the increase magnitude corresponds to the degree of loss. 
     In an embodiment, the display area of the display panel  100  is sequentially divided into a plurality of charging areas according to the number of rows of data lines, and each charging area has a unique digital code. 
     In this scheme, each charging area has a unique digital code. When the gamma voltage generation circuit  122  outputs the gamma voltage for drive, one charging area corresponds to only one gamma voltage, which ensures that the gamma voltage generation circuit generates gamma voltages for accurate voltage compensation for each of the charging areas so that the lightness difference between the respective charging areas of the display panel  100  is reduced or eliminated. 
     In an embodiment, the step of detecting a charging area where the pixel to be charged is located, and outputting a corresponding digital code according to the charging area by a timing control chip  110  includes: 
     the number of rows of counting data lines of the counter  111  of the timing control chip  110 ; 
     the timing control chip  110  identifies the count value of the counter  111 , and obtains and outputs the corresponding digital code from the memory. 
     In the scheme, the timing control chip  110  includes a row counter  111 . Since the principle of the row counter  111  is to count X plus 1 for each row charged, and the distance between the corresponding pixel and the data driving chip  140  varies with the number of rows of the scan lines, the distance between the pixel and the data driving chip  140  can be expressed by the number of rows. In this way, we can design the control mode when the count X is different values according to the requirements. Specifically, for example, we can divide the count X into four steps:  100 ,  200 ,  300  and  400 ; if the row value X is less than or equal to 100, the corresponding digital code 1 (1.1 times the standard gamma voltage) is obtained; if the row value X is greater than or equal to 100 and less than or equal to 200, the corresponding digital code 2 (1.2 times the standard gamma voltage) is obtained; if the row value X is greater than or equal to 200 and less than or equal to 300, the corresponding numeric code 3 (1.3 times the standard gamma voltage) is obtained; if the row value X is greater than or equal to 300 and less than or equal to 400, a numeric code 4 (1.4 times the standard gamma voltage) is obtained. By analogy, there are also four sets of digital codes of different sizes, and the gamma voltage corresponding to each set of digital codes increases in turn; of course, for example, when the reference voltage is equal to the operating voltage multiplied by the digital code, the digital code may also be scaling factor values such as 0.5, 0.55 and 0.6 respectively. 
     The detection and control circuit of the timing control chip  110  recognizes the count value of the row counter  111 , and transmits the corresponding digital code to the gamma chip  120  according to the count value. The gamma chip  120  generates gamma voltages according to the digital code to charge the corresponding charging area according to the digital code, and improves the lightness difference of the different charging areas; in addition, each set of digital codes may include and correspond to a plurality of gamma voltages, and gamma voltages can be adjusted precisely for distant and proximal charging areas. 
     In addition, a detection and control circuit is added to the timing control chip  110  to recognize the different sizes of the X of the row counter  111  and make corresponding different outputs. 
     In an embodiment, the timing control chip  110  can be a timing control chip; the gamma chip  120  can be a gamma chip; the gamma voltage division coefficient memory  123  can be a gamma voltage division coefficient memory; the operating voltage circuit  130  can be an operating voltage circuit; the data driving chip  140  can be a data driving chip. 
     As shown in  FIG.  2   , as an embodiment of the present application, it discloses a driving method of a display panel  100 , including: 
     S 20 : according to the distance from the data driving chip  140 , the display panel being divided into a plurality of charging areas in advance according to the number of rows of data lines, each charging area having a unique digital code, and the corresponding information of the charging area and the digital code being stored in the timing control chip  110  in advance; 
     S 21 : the counter  111  of the timing control chip  110  counting the number of rows of data lines: 
     S 22 : the timing control chip  110  identifying the count value of the counter  111 , and obtaining and outputting the corresponding digital code from the memory  111 ; 
     S 23 : the reference voltage generation circuit  121  receiving the digital code and generating a reference voltage corresponding to the digital code according to the input operating voltage; 
     S 24 : the gamma voltage generation circuit  122  receives a reference voltage and generates a corresponding gamma voltage according to the corresponding gamma voltage division coefficient to drive charging operation of the charging area corresponding to the digital code. 
     In the drive circuit of the scheme, through the timing control chip  110 , the digital code is output to the gamma chip  120  according to the corresponding charging area, the gamma chip  120  further controls the voltage at which the input operates to generate the corresponding reference voltage, and the reference voltage serves as a basis for generating the gamma voltage of the gamma chip  120 ; the gamma voltage stores a large number of gamma voltage division coefficients. By performing voltage division processing in the gamma chip, the gamma voltage of the charging area can be adjusted and the operation of the processing data of the timing control chip  110  can be reduced. The memory space of the timing control chip  110  can be saved, and the manufacturing cost of the display panel can be further reduced. 
     In an embodiment, as shown in  FIGS.  1  to  4   , it discloses a drive circuit  200  of a display panel  100  and the method for using the above drive circuit. 
     It should be noted that, the limitation of the steps involved in this scheme, without affecting the implementation of the specific scheme, it is not determined to limit the sequence of steps, and the previous steps may be executed first, later, or even simultaneously, and shall be deemed to fall within the scope of the present application as long as the scheme can be implemented. 
     The technical scheme of the present application can be widely used in various display panels, such as Twisted Nematic (TN) display panels, In-Plane Switching (IPS) display panels, Vertical Alignment (VA) display panels and Multi-Domain Vertical Alignment (MVA) display panels, and, of course, other types of display panels, such as Organic Light-Emitting Diode (OLED) display panels. 
     The above content is a detailed description of the present application in conjunction with specific alternative embodiments, and it is not to be construed that specific embodiments of the present application are limited to these descriptions. For those of ordinary skill in the art to which this application belongs, a number of simple derivations or substitutions may be made without departing from the spirit of this application, all of which shall be deemed to fall within the scope of this application.