Patent Publication Number: US-11644723-B2

Title: Electrostatic discharge (ESD) protection structure and display panel

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
     This application claims the priority to the Chinese Patent Application 2018113323235, filed with National Intellectual Property Administration, PRC on Nov. 9, 2018 and entitled “ELECTROSTATIC DISCHARGE (ESD) PROTECTION STRUCTURE AND DISPLAY APPARATUS”, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     This application relates to the field of display, and in particular, to an electrostatic discharge (ESD) protection structure and a display apparatus. 
     BACKGROUND 
     Statements herein only provide background information related to this application, and do not necessarily constitute prior art. 
     A thin film transistor liquid crystal display (TFT-LCD) is currently one of main types of flat panel displays, and becomes an important display platform in modern IT and video products. In a main driving principle of the thin film transistor liquid crystal display (TFT-LCD), a system motherboard connects compressed red (R), green (G), and blue (B) signals, a control signal, and power to an electronic connector on a printed circuit board (PCB) through wires. Data is processed by a driving chip (timing controller IC, TCON IC) on the printed circuit board (PCB), and then connected to a display area by the printed circuit board (PCB) through source-chip on film (S-COF) and gate-chip on film (G-COF), so that the liquid crystal display (LCD) obtains required power supply and signals. 
     A refresh rate of a traditional panel is 60 Hz, which means that a screen is refreshed for 60 times per second. Each refresh is to charge and discharge each display pixel in the display area. When a picture is in a fast-moving state (such as playing a video, a game, scrolling, etc.), such refresh rate is still necessary. However, if the picture is a static picture, refreshing is still performed continuously; causing a lot of unnecessary loss of power consumption. 
     SUMMARY 
     In order to resolve defects in the foregoing, this application provides, based on traditional design that only a signal transmission wire is provided, an additional structure to achieve electrostatic discharge (ESD) protection, selective refreshing, and other effects. 
     An objective of this application is achieved by using the following technical solutions and an electrostatic discharge (ESD) protection structure of a display panel is provided according to this application. The ESD protection structure includes: a driving chip configured to send a driving signal; a plurality of signal lines arranged in a display area, where the display area is equally divided into a first signal line area and a second signal line area along a horizontal direction, each of the plurality of signal lines located in the first signal line area is coupled with a positive polarity switch, each of the plurality of signal lines located in the second signal line area is coupled with a negative polarity switch, and the positive polarity switch and the negative polarity switch are electrically connected to the driving chip; and ESD protection circuits, each including a forward diode and a backward diode. When the plurality of signal lines located in the first signal line area output low level signals and the plurality of signal lines located in the second signal line area output high level signals, the display area is not refreshed. 
     In one or more embodiments of this application, the forward diode has unilateral conductivity. 
     In one or more embodiment of this application, the backward diode has unilateral conductivity. 
     In one or more embodiments of this application, when the positive polarity switch and the negative polarity switch are turned on, an output end is electrically connected to an input end. 
     In one or more embodiments of this application, when the output end is electrically connected to the input end, an output value of the output end is equal to an input value of the corresponding input end. 
     In one or more embodiments of this application, when the positive polarity switch and the negative polarity switch are turned off, output of the output end is reversely cut off by the diode. 
     In one or more embodiments of this application, when the output of the output end is reversely cut off by the diode, the input end corresponding to the output end has no input value. 
     In one or more embodiments of this application, during displaying in the display area, a timing controller stores a previous picture and compares the previous picture to a current picture, and when the previous picture and the current picture are different, an output value of the driving signal in the first signal line area is high (H), and an output value of the driving signal in the second signal line area is low (L). 
     In one or more embodiments of this application, during displaying in the display area, a timing controller stores the previous picture and compares the previous picture to the current picture, and when the previous picture and the current picture are the same, the output value of the driving signal in the first signal line area is low (L), and the output value of the driving signal in the second signal line area is high (H), so that a gate output end is disconnected from a corresponding panel input end and the display area is not refreshed. 
     The objective and the solutions of this application may further be implemented in the following technical measures. For a display apparatus provided according to this application, the display apparatus includes a display panel. The display panel includes a plurality of pixels for displaying an image, and includes the foregoing ESD protection structure. 
     Through this application, design of the ESD protection structure is provided, and based on traditional design that only a signal transmission wire is provided, an additional structure is increased to achieve electrostatic discharge (ESD) protection, selective refreshing, and other effects. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram of a driving architecture of a display panel. 
         FIG.  2    is a schematic diagram of design of an electrostatic discharge (ESD) protection structure according to an embodiment of this application. 
         FIG.  3    is a schematic diagram of an ESD protection circuit of a single gate according to an embodiment of this application. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The following embodiments are described with reference to the accompanying drawings, and are used to exemplify particular embodiments that this application can be used to implement. The directional terms mentioned in this application, for example, “upper”, “lower”, “before”, “after”, “left”, “right”, “inside”, “outside”, and “side”, are only references to the directions in the drawings. Therefore, the used direction terms are intended to describe and understand this application, but are not intended to limit this application. 
     The drawings and description are considered to be illustrative in nature rather than restrictive. In the figures, structurally similar units are denoted by the same reference numerals. In addition, for understanding and ease of description, the size and thickness of each component in the drawings are arbitrarily shown, but this application is not limited to this. 
     In addition, in this specification, unless explicitly described to the contrary, the word “including” will be understood to mean including the component but not excluding any other component. Besides, in this specification, “on” means that it is above or below the target component and does not mean that it is necessary to be on top based on the direction of gravity. 
     In order to further explain technical means adopted by this application for achieving an intended application purpose and effects, in combination with the accompanying drawings and optional embodiments, specific implementation, structures, features, and effects of electrostatic discharge (ESD) protection and selective refreshing provided according to this application are described in detail below. 
       FIG.  1    is a schematic diagram of a driving architecture of a display panel.  FIG.  1    illustrates a basic idea of this application. A display panel (thin film transistor liquid crystal display (TFT-LCD)) is currently one of main types of flat panel displays, and becomes an important display platform in modern IT and video products. In a main driving principle of the display panel (thin film transistor liquid crystal display (TFT-LCD)), a system motherboard connects compressed red (R), green (G), and blue (B) signals, a control signal, and power to an electronic connector on a printed circuit board (PCB)  110  through wires. Data is processed by a driving chip (timing controller IC, TCON IC)  120  on the printed circuit board (PCB)  110 , and then connected to a display area  100  by the printed circuit hoard (PCB)  110  through source-chip on film (S-COF)  130  and gate-chip on film (G-COF)  140 , so that the liquid crystal display (LCD) obtains required power supply and signals. 
     In the following embodiments, only a gate is taken as an example for illustration, but not limited thereto. Implementation of this application may be applied to both a source and the gate. 
     With reference to  FIG.  1   ,  FIG.  2   , and  FIG.  3   ,  FIG.  2    is a schematic diagram of design of an electrostatic discharge (ESD) protection structure according to an embodiment of this application.  FIG.  3    is a schematic diagram of an ESD protection circuit of a single gate according to an embodiment of this application. As shown in  FIG.  2   , the ESD protection structure includes a driving chip (timing controller IC, TCON IC)  120 , a gate-chip on film (G-COF)  140 , and a display area  100 . 
     The display panel provided in this application includes the display area and a plurality of gates  140  arranged on a side of the display area. The ESD protection structure includes: a driving chip (timing controller IC, TCON IC)  120  configured to send a driving signal; a plurality of signal lines  143  (see  FIG.  2   ) arranged on a side of the gate  140  of the display area (as shown in  FIG.  1   ), where the display area is equally divided into a first signal line area  145  and a second signal line  145  area along a horizontal direction (see  FIG.  3   ), each of the plurality of signal lines  143  located in the first signal line area  145  is coupled with a positive polarity switch (MOS, M1), each of the plurality of signal lines  143  located in the second signal line area  147  is coupled with a negative polarity switch (MOS, M2), and the positive polarity switch (MOS, M1) and the negative polarity switch (MOS, M2) are electrically connected to the driving chip (timing controller IC, ICON IC)  120 ; and an ESD protection circuit  141  correspondingly arranged on the gate in a one-to-one manner. Each of the ESD protection circuits includes a forward diode (D1) and a backward diode (D1). When the plurality of signal lines  143  located in the first signal line area  145  output low (L) level signals and the plurality of signal lines  143  located in the second signal line area  147  output high (H) level signals, the display area is not refreshed. 
     Further, in  FIG.  3   , D1 is a diode with unilateral conductivity. M1 is a positive polarity switch MOS and is called a positive polarity switch (MOS, M1) below. When a gate voltage thereof is high (H), the positive polarity switch (MOS, M1) is turned on. When the gate voltage thereof is low (L), the positive switch (MOS, M1) is turned off. M2 is a negative switch MOS and is called a negative polarity switch (MOS, M2) below. When the gate voltage thereof is low (L), the negative polarity switch (MOS, M2) is turned on, and when the gate voltage is high (H), the negative polarity switch (MOS, M2) is turned off A control signal C is output of the driving chip (timing controller IC, TCON IC)  120  and is connected to the gates of the positive polarity switch (MOS, M1) and the negative polarity switch (MOS, M2). The panel is divided into two parts along the horizontal direction. The first part has a positive polarity switch (MOS, M1), and the second part has a negative polarity switch (MOS, M2). Specifically, for a machine type with vertical HD resolution of  768 , a gate output end n is a gate output end  384 , a cell panel input end n is a panel input end  384 ; a gate output end n+1 is a gate output end  385 , and a panel input end n+1 is a panel input end  385 ; and a gate output end  2   n  is a gate output end  768 , and a panel input end  2   n  is a panel input end  768 . When the positive polarity switch (MOS, M1) and the negative polarity switch (MOS, M2) are turned on, the gate output end may be connected to a corresponding panel input end, and at this time, and the gate output end=the panel Input end. When the positive polarity switch (MOS, M1) and the negative polarity switch (MOS, M2) are turned off, output of the gate output end is reversely cut off by a backward diode (D1), and the corresponding panel input end has no output. 
     When the panel performs display, the control signal C is controlled by the driving chip (timing controller IC, TCON IC)  120 . When the system is running, normally, the driving chip (timing controller IC, TCON IC)  120  stores a previous picture and compares the previous picture to a current picture. In a case that the previous picture and the current picture are different, when a gate output end  1  to a gate output end n perform output, output of the control signal C is high (H), and when a gate output end n+1 to a gate output end  2   n  perform output, output of the control signal C is low (L). At this time, the gate output end=the panel input end. The panel performs display normally. When the previous picture and the current picture are the same, when the gate output end  1  to the gate output end n perform output, the output of the control signal C is low (L), and when the gate output end n+1 to the gate output end  2   n  perform output, the output of the control signal C is high (H). At this time, the gate output end is disconnected from the panel input end, and the panel input end has no output. At this time, output of the source-chip on film (S-COF) is not input into the display area, and the display area is not refreshed, causing no loss of power consumption. 
     When a positive polarity switch (MOS, M1) of the first part of the panel in the vertical direction is turned on, a negative polarity switch (MOS, M2) of the second part is turned off, and the gate output end of the second part is disconnected from the panel input end. At this time, external electrostatic discharge is not conducted to the inside of a panel through the gate output end, so that a probability of being injured by the electrostatic discharge (ESD) in the panel is reduced. When the negative polarity switch (MOS, M2) is turned on, and the positive polarity switch (MOS, M1) is turned off, in the same principle, the probability of being injured by the electrostatic discharge (ESD) in the first part of the panel is reduced. 
     Based on the foregoing, ESD and selective refreshing can be achieved. 
     In the processing methods in  FIG.  2    and  FIG.  3   , the following advantages are provided. In a case that the previous picture and the current picture are the same, when the gate output end  1  to the gate output end n perform output, the output of the control signal C is low (L), and when the gate output end n+1 to the gate output end  2   n  perform output, the output of the control signal C is high (H). At this time, the gate output end is disconnected from the panel input end, and the panel input end has no output. At this time, output of the source-chip on film (S-COF) is not input into the display area, and the display area is not refreshed, causing no loss of power consumption. 
     In some embodiments, when a positive polarity switch (MOS, M1) of the first part of the display panel in the vertical direction is turned on, and a negative polarity switch (MOS, M2) of the second part is turned off, and the gate output end of the second part is disconnected from the panel input end. At this time, external electrostatic discharge is not conducted to the inside of a panel through the gate output end, so that a probability of being injured by the electrostatic discharge (ESD) in the panel is reduced. When the negative polarity switch (MOS, M2) is turned on, and the positive polarity switch (MOS, M1) is turned off, in the same principle, the probability of being injured by the electrostatic discharge (ESD) in the first part of the panel is reduced. 
     Based on the foregoing methods, the following can be implemented: Based on traditional design that only a signal transmission wire is provided, an additional structure is increased to achieve electrostatic discharge (ESD) protection and selective refreshing. 
     The terms such as “in an embodiment of this application” and “in various embodiments” are repeatedly used. The terms used usually do not refer to the same embodiment, but the terms can also refer to the same embodiment. Words such as “comprise”, “have” and “include” are synonyms, unless the context shows other meanings 
     The above descriptions are merely optional embodiments of this application, and are not intended to restrict the application in any form. Although this application is described above with reference to the optional embodiments, the embodiments are not intended to limit this application. A person of skilled in the art may make some equivalent variations, alterations or modifications to the above-disclosed technical content without departing from the scope of the technical solutions of this application to obtain equivalent embodiments. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the application without departing from the content of the technical solutions of this application shall fall within the scope of the technical solutions of this application.