Line defect detection method and device for display panel

Abstract

The invention discloses a line defect detection method and device for a display panel. The method comprises the following steps: dividing a first pixel driving circuit column with line defects into N pixel driving circuit groups; in the direction from the display area to the binding area, the data lines and the compensation signal lines connected with the first pixel driving circuit columns are sequentially cut off at the positions between every two adjacent pixel driving circuit groups; when the position between the ith pixel driving circuit group and the (i + 1) th pixel driving circuit group is cut off, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the induction line type defect detection signal in the defect detection stage is smaller than a detection threshold value, the detection stage is switched to the (i + 1) th pixel driving circuit group; the defect position of the locking line defect is located in the ith pixel driving circuit group; the induction line type defect detection signal is a difference value between the induction signal before a set time period and after the set time period. According to the technical scheme provided by the invention, the short-circuit line defect position of the display panel can be accurately locked.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a method and device for detecting line defects of a display panel. Background Art

[0002] OLED, or Organic Light-Emitting Diode, is also called an organic electroluminescent device. It refers to the phenomenon that the luminescent material emits light through carrier injection and recombination under the drive of an electric field. Compared with liquid crystal display (LCD) devices, organic light-emitting display devices are lighter and thinner, and have better viewing angles and contrast, etc., so they have attracted widespread attention.

[0003] In the OLED panel process, a large number of metal patterns such as data lines, power signal lines and reference voltage signal lines are set. Among them, because the data lines and reference voltage signal lines are close to each other, there is a possibility that foreign matter from the upper metal layer will fall to the lower metal layer, which can easily lead to a short circuit between the data lines and the reference voltage signal lines, forming a line defect. In the display process of the display panel, dark lines will be formed in the entire row or column, affecting the normal display of the display panel. Summary of the invention

[0004] An embodiment of the present invention provides a method for detecting line defects of a display panel, so as to accurately lock the position of a line defect where a short circuit occurs in the display panel.

[0005] In a first aspect, an embodiment of the present invention provides a method for detecting line defects of a display panel, wherein the display panel comprises a display area and a binding area located at one side of the display area along a first direction; the display area comprises a plurality of pixel driving circuit columns extending along the first direction and arranged in sequence along a second direction; the first direction intersects with the second direction; the display area further comprises a data line and a compensation signal line extending along the first direction; the data line is used to provide a data signal for a corresponding pixel driving circuit; the compensation signal line is used to provide a compensation signal for a corresponding pixel driving circuit and output a sensing signal corresponding to the pixel driving circuit;

[0006] The line defect detection method of the display panel comprises:

[0007] Divide the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction; each of the pixel driving circuit groups includes a plurality of pixel driving circuits; N is an integer greater than 1;

[0008] Cutting off the data lines and compensation signal lines connected to the first pixel driving circuit column in sequence at positions between two adjacent pixel driving circuit groups along the first direction from the display area to the binding area;

[0009] When the data line and the compensation signal line are cut off at the position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after a set time period; 1≤i≤N-1; i is an integer.

[0010] As a preferred scheme of the line defect detection method of the display panel, when the data line and the compensation signal line are cut off to the position between the N-1th pixel driving circuit group and the Nth pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column displays a dark line, and / or the sensing line type bad detection signal obtained according to the sensing signal is greater than or equal to the detection threshold, then the defect position of the locked line defect is located at the Nth pixel driving circuit group.

[0011] As a preferred solution of the method for detecting line defects of a display panel, the set time period is 50S; and the detection threshold is 450-500mA.

[0012] As a preferred solution of the line defect detection method of the display panel, the pixel driving circuit includes: a switching transistor, a driving transistor, a sensing transistor and a storage capacitor; the control end of the switching transistor is connected to a scanning signal; the first end of the switching transistor is electrically connected to the corresponding data line; the second end of the switching transistor is electrically connected to the control end of the driving transistor; the first end of the driving transistor is connected to a first power supply signal; the second end of the driving transistor is electrically connected to the first end of the corresponding light-emitting element; the second end of the light-emitting element is connected to a second power supply signal; the first electrode of the storage capacitor is electrically connected to the control end of the driving transistor; the second electrode of the storage capacitor is electrically connected to the first end of the driving transistor The two ends are electrically connected; the control end of the sensing transistor is connected to a control signal; the first end of the sensing transistor is electrically connected to the second end of the driving transistor; the second end of the sensing transistor is electrically connected to the corresponding compensation signal line; the pixel driving circuit is configured as follows: in the driving stage, the switching transistor, the driving transistor and the sensing transistor are turned on, and the data signal input by the data line and the compensation signal input by the compensation signal line control the light-emitting element to emit light; in the bad detection stage, the switching transistor, the driving transistor and the sensing transistor are turned off; in the first stage, the compensation signal line inputs a charging signal to the second end of the sensing transistor; in the second stage, the compensation signal line outputs a sensing signal.

[0013] As a preferred solution of the line defect detection method of the display panel, before dividing the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction, it also includes: controlling the display panel to execute the driving stage, and obtaining the pixel driving circuit column in which the corresponding light-emitting element in the display area displays a dark line as the first pixel driving circuit column; the dark line is a display state in which the display brightness of the light-emitting element corresponding to the pixel driving circuit column is lower than the brightness threshold.

[0014] As a preferred solution of the method for detecting line defects of a display panel, the brightness threshold is the average brightness of the light-emitting elements corresponding to the pixel driving circuit columns without line defects in the current driving stage.

[0015] As a preferred scheme of the line defect detection method of the display panel, when the data line and the compensation signal line are cut off to the position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel driving circuit group, including: when the data line and the compensation signal line are cut off to the set position of the i-th pixel driving circuit group, controlling the display panel to execute the driving stage, and judging whether the light-emitting element corresponding to the first pixel driving circuit column displays a dark line; and controlling the display panel to execute the sensing stage, and judging whether the sensing line type bad detection signal is less than the detection threshold; if the light-emitting element corresponding to the first pixel driving circuit column does not display a dark line, and / or the sensing line type bad detection signal is less than the detection threshold, then the specific position of the locked line defect is located in the i-th pixel driving circuit group.

[0016] As a preferred solution of the line defect detection method of the display panel, the defect position of the locked line defect is located after the i-th pixel driving circuit group, and also includes: locating the defect position in the i-th pixel driving circuit group to the short-circuit position of the data line and the compensation signal line through a microscope; performing cross-sectional analysis on the short-circuit position through a focused ion beam process and feeding back to the controller.

[0017] As a preferred solution of the line defect detection method of the display panel, the display area includes pixel units arranged in an array; the pixel units include a first pixel driving circuit, a second pixel driving circuit, a third pixel driving circuit and a fourth pixel driving circuit arranged along a second direction;

[0018] The first pixel driving circuit is used to drive the corresponding first color light emitting element; the second pixel driving circuit is used to drive the corresponding second color light emitting element; the third pixel driving circuit is used to drive the corresponding third color light emitting element; the fourth pixel driving circuit is used to drive the corresponding fourth color light emitting element; the pixel units form a pixel unit column along the first direction; the same pixel unit column shares one data line; the same pixel unit column shares one compensation signal line; the line defect detection method of the display panel comprises: dividing the first pixel unit column with line defects into N pixel unit groups along the first direction; cutting off the data line and the compensation signal line connected to the first pixel unit column in the direction from the display area to the binding area along the first direction at the position between two adjacent pixel unit groups; when cutting off the data line and the compensation signal line at the position between the i-th pixel unit group and the i+1-th pixel unit group, if the light emitting element corresponding to the first pixel unit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel unit group.

[0019] In a second aspect, an embodiment of the present invention further provides a line defect detection device for a display panel, which is applicable to the line defect detection method for a display panel provided by any embodiment of the present invention, comprising: a controller and a laser cutting device;

[0020] The controller is used to divide the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction; each of the pixel driving circuit groups includes a plurality of pixel driving circuits; N is an integer greater than 1;

[0021] The laser cutting device is electrically connected to the controller and is used to sequentially cut the data lines and compensation signal lines connected to the first pixel driving circuit column at the position between two adjacent pixel driving circuit groups along the first direction from the display area to the binding area;

[0022] The controller is also used to obtain that the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line when the laser cutting device cuts off the data line and the compensation signal line between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, and accordingly lock the defect position of the line defect to be located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after a set time period; 1≤i≤N-1; i is an integer.

[0023] In the present invention, the display panel includes a pixel driving circuit column extending along a first direction, and if there is a pixel driving circuit column with a line defect, it can be called a first pixel driving circuit column. In the process of line defect detection, the first pixel driving circuit column with a line defect is divided into N pixel driving circuit groups along the first direction; each pixel driving circuit group includes a plurality of pixel driving circuits arranged along the first direction; then, the data lines and compensation signal lines between adjacent pixel driving circuit groups in the first pixel driving circuit column can be cut off one by one from the side away from the binding area, and after cutting off one data line and compensation signal line, the display panel is controlled to be in a driving stage and a bad detection stage in sequence, and in the driving stage, the light-emitting element connected to the first pixel driving circuit column is detected whether it displays a dark line, and the sensing line type bad detection signal is obtained in the bad detection stage. Finally, when the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, it is determined that the defect position of the line defect is located in the i-th pixel driving circuit group. This embodiment can accurately lock the pixel driving circuit group where the line defect occurs, so that subsequent staff can directly lock the short-circuit position of the data line and the compensation signal line from the pixel driving circuit group. There is no need for the staff to check the pixel driving circuits one by one, which improves the efficiency of line defect inspection and the positioning accuracy of line defects, and facilitates tracing and analysis of the causes of line defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic flow chart of a method for detecting line defects of a display panel provided by an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0026] Figure 3 A schematic structural diagram of a pixel driving circuit provided by an embodiment of the present invention;

[0027] Figure 4 A schematic structural diagram of another pixel driving circuit provided by an embodiment of the present invention;

[0028] Figure 5 A waveform diagram of an induction signal provided by an embodiment of the present invention;

[0029] Figure 6 A layout diagram of a pixel driving circuit provided by an embodiment of the present invention;

[0030] Figure 7 for Figure 6 A partial enlarged view of the middle area C1;

[0031] Figure 8 for Figure 7 A magnified view of the local structure at the short-circuit position;

[0032] Fig. 9 A schematic structural diagram of a line defect detection device for a display panel provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] An embodiment of the present invention provides a method for detecting line defects of a display panel, such as Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of a flow chart of a method for detecting line defects of a display panel provided by an embodiment of the present invention, Figure 2 A structural diagram of a display panel provided by an embodiment of the present invention. The display panel includes a display area AA and a binding area B1 located on one side of the display area AA along a first direction Y; the display area AA includes a plurality of pixel driving circuit columns 115 extending along the first direction Y and arranged in sequence along a second direction X; the first direction Y intersects with the second direction X, and optionally, the first direction Y and the second direction X can be arranged perpendicularly; the display area AA also includes a data line ( Figure 2 Not shown) and compensation signal line ( Figure 2 The data line is used to provide a data signal to the corresponding pixel driving circuit; the compensation signal line is used to provide a compensation signal to the corresponding pixel driving circuit and output a sensing signal of the corresponding pixel driving circuit;

[0035] Specifically, the method for detecting line defects of a display panel includes the following steps:

[0036] Step S101 : dividing a first pixel driving circuit column with line defects into N pixel driving circuit groups along a first direction; each pixel driving circuit group includes a plurality of pixel driving circuits; and N is an integer greater than 1.

[0037] Figure 3 A schematic diagram of a pixel driving circuit according to an embodiment of the present invention is provided. Figure 2 and Figure 3In this embodiment, a pixel driving circuit column 115 that may have a line defect among the plurality of pixel driving circuit columns 115 has a light emitting element 114 whose brightness is significantly lower than that of the light emitting elements 114 of other pixel driving circuit columns during the normal driving process of the display panel, forming a dark line on the display effect. In this embodiment, the pixel driving circuit column that forms a dark line on the display effect may be called the first pixel driving circuit column 112, and the first pixel driving circuit column 112 is divided into N pixel driving circuit groups 111 along the first direction Y. The pixel driving circuit group 111 includes a plurality of pixel driving circuits 113 arranged in sequence along the first direction Y, and each pixel driving circuit 113 is used to provide a driving current for a corresponding light emitting element 114.

[0038] Step S102 , cutting off the data lines and compensation signal lines connected to the first pixel driving circuit column in sequence at a position between two adjacent pixel driving circuit groups along a first direction from the display area to the binding area.

[0039] Figure 4 A schematic diagram of another pixel driving circuit provided by an embodiment of the present invention, referring to Figure 3 and Figure 4 The data line Vdata and the compensation signal line Vref extend along the first direction Y. When the data line Vdata and the compensation signal line Vref are cut, the data line Vdata and the compensation signal line Vref need to be cut in a direction perpendicular to the first direction Y. The cutting position is the position between two adjacent pixel driving circuit groups 111. Figure 4 As shown, the cutting position 21 marked with "×" in the figure is the position where the pixel driving circuit groups are cut.

[0040] Step S103, when the data line and the compensation signal line are cut off to the position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after the set time period; 1≤i≤N-1; i is an integer.

[0041] Continue to refer Figure 3 and Figure 4Optionally, the pixel driving circuit includes: a switching transistor T1, a driving transistor T2, a sensing transistor T3 and a storage capacitor Cst; the control end of the switching transistor T1 is connected to the scanning signal SCAN; the first end of the switching transistor T1 is electrically connected to the corresponding data line Vdata; the second end of the switching transistor T1 is electrically connected to the control end of the driving transistor T2; the first end of the driving transistor T2 is connected to the first power signal EVDD; the second end of the driving transistor T2 is electrically connected to the first end of the corresponding light-emitting element 114; the second end of the light-emitting element 114 is connected to the second power signal EVSS; the first electrode of the storage capacitor Cst is electrically connected to the control end of the driving transistor T2; the second electrode of the storage capacitor Cst is electrically connected to the second end of the driving transistor T2; the control end of the sensing transistor T3 is connected to the control signal SENSE; the sensing The first end of the transistor T3 is electrically connected to the second end of the driving transistor T2; the second end of the sensing transistor T3 is electrically connected to the corresponding compensation signal line Vref; the pixel driving circuit is configured as follows: in the driving stage, the switching transistor T1, the driving transistor T2 and the sensing transistor T3 are turned on, and the data signal input by the data line Vdata and the compensation signal input by the compensation signal line Vref control the light-emitting element 114 to emit light; in the driving stage, all transistors are turned on to drive the light-emitting element 114, and the compensation signal line Vref can output the driving current of the light-emitting element 114 to the controller. When the controller detects that the driving current of the light-emitting element 114 is different from that of the surrounding light-emitting elements, the corresponding compensation current can be calculated and generated, and the compensation current is transmitted to the first end of the light-emitting element 114 through the compensation signal line Vref and the sensing transistor T3. When the data line Vdata and the compensation signal line Vref are not short-circuited, the data signal of the data line Vdata and the compensation signal input by the compensation signal line Vref jointly apply a voltage to drive the light-emitting element 114. However, when the data line Vdata and the compensation signal line Vref are short-circuited, the voltage value detected by the second end of the sensing transistor T3 will increase, and the compensation current transmitted by the compensation signal line Vref to the second end of the sensing transistor T3 will be reduced, resulting in that when the display panel is driven normally, the compensation value of the compensation signal line Vref for the first pixel driving circuit column is lower than the compensation value of the surrounding pixel driving circuit columns, and the display effect presented is that the first pixel driving circuit column forms a dark line with a brightness lower than that of the surrounding pixel driving circuit columns.

[0042] In the bad detection stage, the switch transistor T1, the driving transistor T2 and the sensing transistor T3 are turned off; in the first stage, the compensation signal line Vref inputs a charging signal to the second end of the sensing transistor T3 to charge the second end of the sensing transistor T3; in the second stage, the compensation signal line Vref outputs a sensing signal to detect the discharge state of the second end of the sensing transistor T3, specifically detecting the falling speed of the sensing current at the second end of the sensing transistor T3. If the data line Vdata and the compensation signal line Vref are short-circuited at this time, the sensing current output from the second end will decrease rapidly.

[0043] When cutting to the data line and compensation signal line between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, first, it is necessary to control the display panel to enter the driving stage, and determine whether the light-emitting element corresponding to the first pixel driving circuit column displays a dark line. It should be noted that the display of a dark line means that there is a short circuit between the data line Vdata and the compensation signal line Vref, and the disappearance of the dark line (increase in display brightness) means that there is no short circuit between the data line Vdata and the compensation signal line Vref. If the data line and compensation signal line between the i-1-th pixel driving circuit group and the i-th pixel driving circuit group are cut, it is detected that the light-emitting element corresponding to the first pixel driving circuit column displays a dark line, and when the data line and compensation signal line between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group are cut, it is detected that the dark line of the light-emitting element corresponding to the first pixel driving circuit column disappears, then it can be determined that the short circuit position is within the i-th pixel driving circuit group.

[0044] Similarly, it is also necessary to control the display panel to enter the bad detection stage, which includes the first stage and the second stage. Specifically, a charging signal is input in the first stage, and the second stage is directly entered after the charging is completed, that is, the detection compensation signal line Vref outputs a sensing signal. When the difference between the sensing signal before and after the set time period is large, or the sensing current drop value is large within the set time period, that is, when the sensing line type bad detection signal (Sensing LDDetection, SLDD) is too large (greater than or equal to the detection threshold), it indicates that there is a short circuit phenomenon. When the sensing line type bad detection signal is less than the detection threshold, there is no short circuit line type. In this embodiment, if the sensing line type bad detection signal is greater than or equal to the detection threshold when the data line and the compensation signal line are cut to the position between the i-1 pixel driving circuit group and the i-th pixel driving circuit group, the sensing line type bad detection signal is greater than or equal to the detection threshold, and when the data line and the compensation signal line are cut to the position between the i-th pixel driving circuit group and the i+1th pixel driving circuit group, the sensing line type bad detection signal is less than the detection threshold, then it can be determined that the short circuit position is within the i-th pixel driving circuit group. In this embodiment, one of the above two judgment conditions may be selected to judge the position of the line defect, or both judgment conditions may be selected at the same time to enhance the accuracy of the final short circuit position judgment.

[0045] Figure 5 The waveform diagram of the sensing signal provided by the embodiment of the present invention. Optionally, the time period is set to 50S; the detection threshold is 450-500mA. When there is a short circuit between the compensation signal line Vref and the data line Vdata, the short circuit situation is judged by the difference in discharge degree. In the first stage, all transistors are in the off state, and the charging voltage input to the second end of the sensing transistor T3 can be 3V (lower). After charging, it enters the second stage and detects the induced current after a certain period of time (every 5S). Draw a discharge curve, Figure 5 The discharge curve without short circuit is shown in the figure: normal line; and the discharge curve with short circuit discharge is shown in the figure: bad line. The current drop value in the bad line is greater than the current drop value in the normal line. For example, when the difference of the sensed current is greater than 450mA within the set time period 50S, the discharge curve is a bad line, which can be defined as the NG state, and at this time, the compensation signal line Vref is short-circuited.

[0046] In an embodiment of the present invention, the display panel includes a pixel driving circuit column extending along a first direction, and if there is a pixel driving circuit column with a line defect, it can be called a first pixel driving circuit column. In the process of line defect detection, the first pixel driving circuit column with a line defect is divided into N pixel driving circuit groups along the first direction; each pixel driving circuit group includes a plurality of pixel driving circuits arranged along the first direction; then, the data lines and compensation signal lines between adjacent pixel driving circuit groups in the first pixel driving circuit column can be cut off one by one from the side away from the binding area, and after cutting off one data line and compensation signal line, the display panel is controlled to be in a driving stage and a bad detection stage in sequence, and whether the light-emitting element connected to the first pixel driving circuit column displays a dark line during the driving stage, and a sensing line type bad detection signal is obtained during the bad detection stage. Finally, when the light-emitting element corresponding to the first pixel driving circuit column does not display a dark line during the driving stage, or the sensing line type bad detection signal during the bad detection stage is less than the detection threshold, it is determined that the defect position of the line defect is located in the i-th pixel driving circuit group. This embodiment can accurately lock the pixel driving circuit group where the line defect occurs, so that subsequent staff can directly lock the short-circuit position of the data line and the compensation signal line from the pixel driving circuit group. There is no need for the staff to check the pixel driving circuits one by one, which improves the efficiency of line defect inspection and the positioning accuracy of line defects, and facilitates tracing and analysis of the causes of line defects.

[0047] The above is the core idea of ​​the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] On the basis of the above embodiment, when the data line and the compensation signal line are cut off to the position between the N-1th pixel driving circuit group and the Nth pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column displays a dark line, and / or the sensing line type bad detection signal obtained according to the sensing signal is greater than or equal to the detection threshold, then the defect position of the locked line defect is located in the Nth pixel driving circuit group.

[0049] When the data line and the compensation signal line between the N-1 pixel driving circuit group and the N pixel driving circuit group are cut off, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, the defect position of the locked line defect is located in the N-1 pixel driving circuit group. It is worth noting that if the data line and the compensation signal line between the N-1 pixel driving circuit group and the N pixel driving circuit group are cut off, the light-emitting element corresponding to the first pixel driving circuit column still displays a dark line, or the sensing line type bad detection signal is greater than or equal to the detection threshold, it means that the short circuit position is not in the N-1 pixel driving circuit group, but in the N pixel driving circuit group. In this embodiment, when the data line and the compensation signal line between the N-1 pixel driving circuit group and the N pixel driving circuit group are cut off, it can be determined whether the position of the final line defect is in the N-1 pixel driving circuit group or in the N pixel driving circuit group. The line defect detection method in this embodiment can quickly lock a specific pixel driving circuit group, thereby improving the reliability of line defect detection.

[0050] Optionally, each pixel driving circuit group includes M pixel driving circuits; M is an integer greater than 1. In this embodiment, the first pixel driving circuit column can be evenly divided into N first pixel driving circuit columns along the first direction, that is, each group includes M pixel driving circuits, thereby improving the clarity of the pixel driving circuit group range and further improving the accuracy of short circuit position detection.

[0051] Optionally, before dividing the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction, it also includes: controlling the display panel to execute the driving stage, and obtaining the pixel driving circuit column in the display area where the corresponding light-emitting element is displayed as a dark line as the first pixel driving circuit column; the dark line is a display state in which the display brightness of the light-emitting element corresponding to the pixel driving circuit column is lower than the brightness threshold. Optionally, the brightness threshold is the average brightness of the light-emitting element corresponding to the pixel driving circuit column without line defects in the current driving stage. In this embodiment, the dark line is a display state in which the display brightness of the light-emitting element corresponding to the pixel driving circuit column is lower than the brightness threshold. The brightness threshold can be based on the average brightness of the light-emitting elements corresponding to other pixel driving circuit columns except the first pixel driving circuit column in the current frame, or it can be other values ​​set by the controller that meet the line defect judgment. This embodiment does not specifically limit this. In addition, the brightness threshold may not be set to the average brightness of the light-emitting element corresponding to the pixel driving circuit column without line defects. Instead, the value is taken as the brightness range of the light-emitting elements corresponding to the pixel driving circuit column without line defects. For example, if the brightness of the light-emitting elements specified by the pixel driving circuit column without line defects is as low as the first brightness value and as high as the second brightness value, then the brightness threshold can be the brightness range between the first brightness value and the second brightness value, and the display brightness of the light-emitting elements corresponding to the first pixel driving circuit column is lower than the above brightness range.

[0052] Optionally, when the data line and the compensation signal line at the position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group are cut off, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locking line defect is located in the i-th pixel driving circuit group, including: when the data line and the compensation signal line at the set position of the i-th pixel driving circuit group are cut off, the display panel is controlled to execute the driving stage, and whether the light-emitting element corresponding to the first pixel driving circuit column displays a dark line; and the display panel is controlled to execute the sensing stage, and whether the sensing line type bad detection signal is less than the detection threshold; if the light-emitting element corresponding to the first pixel driving circuit column does not display a dark line, and / or the sensing line type bad detection signal is less than the detection threshold, then the specific position of the locking line defect is located in the i-th pixel driving circuit group. As can be seen from the above, in this embodiment, when the data line and the compensation signal line between two adjacent pixel driving circuit groups are cut off, the driving stage and the sensing stage need to be executed once. In the driving stage, the entire display panel is driven normally so that the first pixel driving circuit column presents a bright line or a dark line; in the sensing stage, the display panel is not driven normally, but a charging signal is passed through the second end of the sensing transistor T3 in the first stage of the sensing stage, and a sensing signal is detected at the second end of the sensing transistor T3 in the second stage to determine whether the sensing line type bad detection signal is less than the detection threshold. Through different detection means in the two stages, the accuracy of line defect detection of the display panel is further enhanced.

[0053] Optionally, after the defect position of the locked line defect is located at the i-th pixel driving circuit group, it also includes: locating the defect position in the i-th pixel driving circuit group to the short-circuit position of the data line and the compensation signal line through a microscope; performing cross-sectional analysis on the short-circuit position through a focused ion beam process and feeding back to the controller. After determining the pixel driving circuit group where the final line defect is located, the pixel driving circuit group can also be magnified through a microscope to specifically determine the short-circuit position to the specific pixel driving circuit location. Finally, the short-circuit position is analyzed through a focused ion beam process and fed back to the controller, so as to analyze the cause of the short circuit and the film layer where the impurities causing the short circuit are located, and then improve the process of the film layer where the impurities are located to prevent the problem of line defects from occurring in the process.

[0054] Figure 6 This is a layout diagram of a pixel driving circuit provided in an embodiment of the present invention. Figure 7 for Figure 6 A partial enlarged view of the middle area C1. Figure 8 for Figure 7 A magnified view of the local structure of the short-circuit position C2. Optionally, the display area includes pixel units arranged in an array; Figure 6 for Figure 4 The layout diagram of the pixel unit in the embodiment of the present invention, the pixel unit includes a first pixel driving circuit 1131, a second pixel driving circuit 1132, a third pixel driving circuit 1133 and a fourth pixel driving circuit 1134 arranged along the second direction X; the first pixel driving circuit 1131 is used to drive the corresponding first color light emitting element B; the second pixel driving circuit 1132 is used to drive the corresponding second color light emitting element W; the third pixel driving circuit 1133 is used to drive the corresponding third color light emitting element R; the fourth pixel driving circuit 1134 is used to drive the corresponding fourth color light emitting element G; the pixel unit forms a pixel unit column along the first direction Y; the same pixel unit column shares a data line (data line Vdata (B), data line Vdata (W), data line Vdata (R) and data line Vdata (G) can be time-division multiplexed) A data line Vdata is used to reduce the number of terminals of the driving chip of the display panel); a compensation signal line Vref is used in common for the same pixel unit column; a line defect detection method for a display panel includes: dividing a first pixel unit column with a line defect into N pixel unit groups along a first direction; cutting off the data line Vdata and the compensation signal line Vref connected to the first pixel unit column in the direction from the display area to the binding area in the first direction Y in sequence at the position between two adjacent pixel unit groups; when the data line and the compensation signal line are cut off at the position between the i-th pixel unit group and the i+1-th pixel unit group, if the light-emitting element corresponding to the first pixel unit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, the defect position of the locked line defect is located in the i-th pixel unit group. It should be noted that after the pixel unit C1 where the short circuit is located is determined by a microscopic device, it is necessary to further determine the pixel driving circuit where the short circuit is located. For example, after determining the specific pixel unit group, microscope analysis is performed, and image processing is used to distinguish the 200 pixel drive circuits between the groups. Through photo identification and comparison with the microscope image of the normal pixel drive circuit, the abnormal area C2 obtained by comparison is saved and the magnification is confirmed, so as to realize automatic search for the short circuit position on the panel.

[0055] Based on the same concept, an embodiment of the present invention further provides a line defect detection device for a display panel, which is applicable to the line defect detection method for a display panel provided by any embodiment of the present invention. Fig. 9 A schematic structural diagram of a line defect detection device for a display panel provided by an embodiment of the present invention includes: a controller 331 and a laser cutting device 332;

[0056] The controller 331 is used to divide the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction; each pixel driving circuit group includes a plurality of pixel driving circuits; N is an integer greater than 1;

[0057] The laser cutting device 332 is electrically connected to the controller 331, and is used to sequentially cut the data lines and compensation signal lines connected to the first pixel driving circuit column at the position between two adjacent pixel driving circuit groups along the first direction from the display area to the binding area;

[0058] The controller is also used to obtain that the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line when the laser cutting device cuts off the data line and the compensation signal line between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, and accordingly lock the defect position of the line defect to be located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after a set time period; 1≤i≤N-1; i is an integer.

[0059] In this embodiment, the display panel includes a pixel driving circuit column extending along a first direction, and if there is a pixel driving circuit column with a line defect, it can be called a first pixel driving circuit column. In the process of line defect detection, the first pixel driving circuit column with a line defect is divided into N pixel driving circuit groups along the first direction; each pixel driving circuit group includes a plurality of pixel driving circuits arranged along the first direction; then, the data lines and compensation signal lines between adjacent pixel driving circuit groups in the first pixel driving circuit column can be cut off one by one from the side away from the binding area, and after cutting off one data line and compensation signal line, the display panel is controlled to be in a driving stage and a bad detection stage in sequence, and whether the light-emitting element connected to the first pixel driving circuit column displays a dark line in the driving stage is detected, and a sensing line type bad detection signal is obtained in the bad detection stage. Finally, when the light-emitting element corresponding to the first pixel driving circuit column does not display a dark line in the driving stage, or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, it is determined that the defect position of the line defect is located in the i-th pixel driving circuit group. This embodiment can accurately lock the pixel driving circuit group where the line defect occurs, so that subsequent staff can directly lock the short-circuit position of the data line and the compensation signal line from the pixel driving circuit group. There is no need for the staff to check the pixel driving circuits one by one, which improves the efficiency of line defect inspection and the positioning accuracy of line defects, and facilitates tracing and analysis of the causes of line defects.

[0060] The line defect detection device in this embodiment includes the technical features of the line defect detection method of any embodiment of the present invention, and has the beneficial effects of the technical features, which will not be repeated here.

[0061] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for detecting line defects of a display panel, characterized in that: The display panel comprises a display area and a binding area located at one side of the display area along a first direction; the display area comprises a plurality of pixel driving circuit columns extending along the first direction and arranged in sequence along a second direction; the first direction intersects with the second direction; the display area further comprises a data line and a compensation signal line extending along the first direction; the data line is used to provide a data signal for a corresponding pixel driving circuit; the compensation signal line is used to provide a compensation signal for a corresponding pixel driving circuit and output a sensing signal corresponding to the pixel driving circuit; The line defect detection method of the display panel comprises: Divide the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction; each of the pixel driving circuit groups includes a plurality of pixel driving circuits; N is an integer greater than 1; Cutting off the data lines and compensation signal lines connected to the first pixel driving circuit column in sequence at positions between two adjacent pixel driving circuit groups along the first direction from the display area to the binding area; When the data line and the compensation signal line are cut off at the position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after a set time period; 1≤i≤N-1; i is an integer.

2. The method for detecting line defects of a display panel according to claim 1, characterized in that: When the data line and the compensation signal line are cut off to the position between the N-1th pixel driving circuit group and the Nth pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column displays a dark line, and / or the sensing line type bad detection signal obtained according to the sensing signal is greater than or equal to the detection threshold, then the defect position of the locked line defect is located in the Nth pixel driving circuit group.

3. The method for detecting line defects of a display panel according to claim 1, characterized in that: The set time period is 50S; the detection threshold is 450-500mA.

4. The method for detecting line defects of a display panel according to claim 1, wherein: The pixel driving circuit comprises: a switch transistor, a driving transistor, a sensing transistor and a storage capacitor; The control end of the switch transistor is connected to the scanning signal; the first end of the switch transistor is electrically connected to the corresponding data line; the second end of the switch transistor is electrically connected to the control end of the drive transistor; the first end of the drive transistor is connected to the first power signal; the second end of the drive transistor is electrically connected to the first end of the corresponding light-emitting element; the second end of the light-emitting element is connected to the second power signal; the first electrode of the storage capacitor is electrically connected to the control end of the drive transistor; the second electrode of the storage capacitor is electrically connected to the second end of the drive transistor; The control terminal of the sensing transistor is connected to a control signal; the first terminal of the sensing transistor is electrically connected to the second terminal of the driving transistor; the second terminal of the sensing transistor is electrically connected to the corresponding compensation signal line; The pixel driving circuit is configured as follows: In the driving stage, the switch transistor, the driving transistor and the sensing transistor are turned on, and the data signal input by the data line and the compensation signal input by the compensation signal line control the light emitting element to emit light; In the bad detection stage, the switch transistor, the driving transistor and the sensing transistor are turned off; in the first stage, the compensation signal line inputs a charging signal to the second end of the sensing transistor; in the second stage, the compensation signal line outputs a sensing signal.

5. The method for detecting line defects of a display panel according to claim 1, characterized in that: Before dividing the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction, the method further includes: The display panel is controlled to execute a driving phase, and a pixel driving circuit column corresponding to a light-emitting element in a display area displayed as a dark line is obtained as a first pixel driving circuit column; the dark line is a display state in which the display brightness of the light-emitting element corresponding to the pixel driving circuit column is lower than a brightness threshold.

6. The method for detecting line defects of a display panel according to claim 5, characterized in that: The brightness threshold is the average brightness of the light-emitting elements corresponding to the pixel driving circuit columns without line defects in the current driving stage.

7. The method for detecting line defects of a display panel according to claim 1, characterized in that: When the data line and the compensation signal line are cut off at a position between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, if the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locking line defect is located in the i-th pixel driving circuit group, including: When the data line and the compensation signal line at the set position of the i-th pixel driving circuit group are cut off, the display panel is controlled to perform a driving phase, and it is determined whether the light-emitting element corresponding to the first pixel driving circuit column displays a dark line; and the display panel is controlled to perform a sensing phase, and it is determined whether the sensing line type bad detection signal is less than a detection threshold; If the light emitting element corresponding to the first pixel driving circuit column does not display a dark line, and / or the sensing line defect detection signal is less than the detection threshold, the specific position of the locking line defect is located in the i-th pixel driving circuit group.

8. The method for detecting line defects of a display panel according to claim 1, wherein: The defect position of the locking line defect is located after the i-th pixel driving circuit group, and further includes: Using a microscope, locate the defective position in the i-th pixel driving circuit group to the short-circuit position between the data line and the compensation signal line; The short circuit position is subjected to cross-sectional analysis through a focused ion beam process and the analysis is fed back to a controller.

9. The method for detecting line defects of a display panel according to claim 8, characterized in that: The display area includes pixel units arranged in an array; the pixel units include a first pixel driving circuit, a second pixel driving circuit, a third pixel driving circuit and a fourth pixel driving circuit arranged along a second direction; The first pixel driving circuit is used to drive the corresponding first color light emitting element; The second pixel driving circuit is used to drive the corresponding second color light emitting element; The third pixel driving circuit is used to drive the corresponding third color light emitting element; The fourth pixel driving circuit is used to drive the corresponding fourth color light emitting element; The pixel units form a pixel unit column along the first direction; The same pixel unit column shares one data line; The same pixel unit column shares a compensation signal line; The line defect detection method of the display panel comprises: Dividing a first pixel unit column having line defects into N pixel unit groups along the first direction; Cutting off the data lines and compensation signal lines connected to the first pixel unit column in sequence at positions between two adjacent pixel unit groups along the first direction from the display area to the binding area; When the data line and the compensation signal line are cut off to the position between the i-th pixel unit group and the i+1-th pixel unit group, if the light-emitting element corresponding to the first pixel unit column in the driving stage does not display a dark line, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, then the defect position of the locked line defect is located in the i-th pixel unit group.

10. A line defect detection device for a display panel, characterized in that: A line defect detection method for a display panel applicable to any one of claims 1 to 9, comprising: a controller and a laser cutting device; The controller is used to divide the first pixel driving circuit column with line defects into N pixel driving circuit groups along the first direction; each of the pixel driving circuit groups includes a plurality of pixel driving circuits; N is an integer greater than 1; The laser cutting device is electrically connected to the controller and is used to sequentially cut the data lines and compensation signal lines connected to the first pixel driving circuit column at the position between two adjacent pixel driving circuit groups along the first direction from the display area to the binding area; The controller is also used to obtain that the light-emitting element corresponding to the first pixel driving circuit column in the driving stage does not display a dark line when the laser cutting device cuts off the data line and the compensation signal line between the i-th pixel driving circuit group and the i+1-th pixel driving circuit group, and / or the sensing line type bad detection signal in the bad detection stage is less than the detection threshold, and accordingly lock the defect position of the line defect to be located in the i-th pixel driving circuit group; the sensing line type bad detection signal is the difference between the sensing signal before and after a set time period; 1≤i≤N-1; i is an integer.

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