Display substrate, method for detecting crack thereof, and display panel

Abstract

The present invention provides a display substrate, a method for detecting cracks thereof, and a display panel. The display substrate has a display area and an edge area, and the edge area surrounds the periphery of the display area; the display substrate includes a substrate and pixel circuits, and the pixel circuits are disposed on the substrate; it further includes a crack detection circuit, which is disposed on the substrate and located in the edge area; the crack detection circuit includes a switching circuit and a trace, and the trace connects the switching circuit and the pixel circuits to form a loop for detecting whether there are cracks in the edge area. For this display substrate, by providing the crack detection circuit, it can conveniently and quickly detect whether cracks appear in the edge area. Compared with the current method of detecting cracks by detecting the resistance of the trace, it not only improves the detection efficiency, but also makes the detection result more accurate.

Description

Technical Field

[0001] The present invention belongs to the technical field of displays, and particularly relates to a display substrate, a method for detecting cracks thereof, and a display panel. Background Art

[0002] At present, flexible OLED (Organic Light-Emitting Diode) display products are becoming increasingly popular because they are thinner, brighter, lower power consumption, faster response, higher clarity, better flexibility, and higher luminous efficiency, and can meet the new demands of consumers for display technology.

[0003] For flexible OLED display screens, when they are bumped during preparation or transportation, cracks are easily generated at the edges. Edge cracks can easily cause open circuits in the internal circuit traces, seriously affecting the display quality of the products. Currently, the commonly used method for detecting edge cracks is to detect whether there are edge cracks by detecting the resistance of the traces. This method has low detection efficiency and inaccurate detection results. Summary of the Invention

[0004] In view of the above problems, the present invention provides a display substrate, a method for detecting cracks thereof, and a display panel. By providing a crack detection circuit, the display substrate can conveniently and quickly detect whether cracks appear in the edge area. Compared with the current method of detecting cracks by detecting the resistance of the traces, the detection efficiency is not only improved, but also the detection results can be made more accurate.

[0005] The present invention provides a display substrate having a display area and an edge area, and the edge area surrounds the periphery of the display area;

[0006] The display substrate includes a substrate and a pixel circuit, and the pixel circuit is disposed on the substrate;

[0007] It further includes a crack detection circuit disposed on the substrate and located in the edge area; the crack detection circuit includes a switch circuit and a trace, and the trace connects the switch circuit and the pixel circuit to form a loop for detecting whether there are cracks in the edge area.

[0008] Optionally, the pixel circuit includes a first reference potential terminal and a ground terminal;

[0009] One end of the trace is connected to the first end of the switch circuit, and the other end is connected to a detection signal input terminal;

[0010] The second end of the switch circuit is connected to the first reference potential terminal; the third end of the switch circuit is connected to the ground terminal.

[0011] Optionally, the trace winds around the display area at least once.

[0012] Optionally, the switching circuit includes a first transistor and a second transistor;

[0013] The gates of the first transistor and the second transistor are connected to one end of the trace;

[0014] A first pole of the first transistor is connected to the first reference potential terminal; a second pole of the first transistor is connected to a first pole of the second transistor; a second pole of the second transistor is connected to the ground terminal.

[0015] Optionally, the switching circuit includes a first transistor;

[0016] The gate of the first transistor is connected to one end of the trace;

[0017] A first pole of the first transistor is connected to the first reference potential terminal; a second pole of the first transistor is connected to the ground terminal.

[0018] Optionally, the first transistor and the second transistor are P-type transistors or N-type transistors.

[0019] Optionally, the pixel circuit further includes a control transistor;

[0020] The gates of the first transistor and the second transistor are on the same layer and made of the same material as the gate of the control transistor;

[0021] The first and second poles of the first transistor, the first and second poles of the second transistor are on the same layer and made of the same material as the first and second poles of the control transistor;

[0022] The active layers of the first transistor and the second transistor are on the same layer and made of the same material as the active layer of the control transistor;

[0023] The trace is on the same layer and made of the same material as the first and second poles of the control transistor;

[0024] Alternatively, the trace is on the same layer and made of the same material as the gate of the control transistor.

[0025] The present invention also provides a display panel, including the above display substrate.

[0026] The present invention also provides a method for detecting cracks in the above display substrate, including: when the display substrate is in a display mode, a detection signal input through a detection signal input terminal causes the switching circuit to turn off, and there is an open circuit between the first reference potential terminal and the ground terminal;

[0027] When the display substrate is in the detection mode, the detection signal inputted at the detection signal input terminal turns on the switching circuit, and a short circuit is formed between the first reference potential terminal and the ground terminal.

[0028] Optionally, when the display substrate is in the detection mode and there is a crack in the edge area of the display substrate, an open circuit is formed between the first reference potential terminal and the ground terminal, and the display substrate displays a non - yellow normal gray - scale picture;

[0029] When there is no crack in the edge area of the display substrate, a conducting path is formed between the first reference potential terminal and the ground terminal, and the non - yellow picture displayed by the display substrate turns yellow.

[0030] Advantages of the present invention: The display substrate provided by the present invention is provided with a crack detection circuit in the edge area of the display substrate. When a crack appears in the edge area, it will cause an open circuit in the crack detection circuit, and then an open circuit will occur in the loop formed by the trace, the switching circuit, and the pixel circuit. According to the display picture phenomenon when the crack detection circuit has an open circuit, it is determined whether there is a crack in the edge area, so as to more conveniently and quickly detect whether there is a crack in the edge area. Compared with the current method of detecting cracks by detecting the resistance of the trace, it not only improves the detection efficiency, but also makes the detection result more accurate; in addition, the preparation of the crack detection circuit in the display substrate does not require additional preparation process steps of the display substrate, saving the preparation process cost.

[0031] The display panel provided by the present invention can more accurately detect whether there is a crack on the display panel and improve the crack detection efficiency by adopting the above - mentioned display substrate. Brief Description of the Drawings

[0032] Figure 1 It is a schematic diagram of a short circuit occurring between the first reference potential terminal and the ground terminal of the OLED display screen;

[0033] Figure 2 It is a top - view schematic diagram of the display substrate in the embodiment of the present invention;

[0034] Figure 3 It is a circuit distribution diagram of a crack detection circuit in the display substrate of the embodiment of the present invention;

[0035] Figure 4 For Figure 3 The structural cross - sectional schematic diagram of the crack detection circuit along the AA cutting line in

[0036] Figure 5 It is another circuit distribution diagram of the crack detection circuit in the display substrate of the embodiment of the present invention;

[0037] Figure 6This is the schematic diagram of the operation of the crack detection circuit when the display substrate is in the display mode in the embodiments of the present invention;

[0038] Figure 7 This is the schematic diagram of the operation of detecting no crack when the display substrate is in the crack detection mode in the embodiments of the present invention;

[0039] Figure 8 This is the schematic diagram of the operation of detecting a crack when the display substrate is in the crack detection mode in the embodiments of the present invention;

[0040] Figure 9 This is another circuit distribution diagram of the crack detection circuit in the display substrate in the embodiments of the present invention;

[0041] Figure 10 This is a schematic diagram of the preparation process of the crack detection circuit in the display substrate in the embodiments of the present invention.

[0042] Among them, the reference numerals are:

[0043] 1. Substrate; 101. Display area; 102. Edge area; 2. Crack detection circuit; 21. Switch circuit; 210. Gate; 211. First pole; 212. Second pole; 213. Active layer; 22. Trace; 3. First reference potential terminal; 4. Ground terminal; 5. Detection signal input terminal; 6. First insulating layer; 7. Second insulating layer; 8. Planarization layer. Detailed implementation manners

[0044] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners for a display substrate, a method for detecting cracks therein, and a display panel.

[0045] In the publicly known technology, taking a certain model of OLED display screen as an example, as Figure 1 shown, when the OLED display screen is displaying normally, it shows a normal gray-scale transition picture. When a short circuit occurs between the first reference potential terminal (i.e., ELVSS) and the ground terminal (i.e., GND) in the edge area surrounding the display area of the OLED display screen, the potential of ELVSS changes from the original design of -3V to 0V, and the gray-scale transition picture displayed on the OLED display screen shows a yellowing phenomenon; the principle analysis is that ELVSS and GND are short-circuited through the conductive adhesive. Among them, the first reference potential terminal ELVSS and the second reference potential terminal ELVDD are respectively connected to the two poles of the OLED light-emitting device to provide a reference potential for the OLED light-emitting device.

[0046] In order to better solve the problem of detecting edge fragmentation of the OLED display screen, the present invention utilizes the phenomenon that when a short circuit occurs between ELVSS and GND, the display picture of the OLED display screen will turn yellow, and designs the following solutions.

[0047] An embodiment of the present invention provides a display substrate, as Figures 2 - 5 shown, having a display area 101 and a peripheral area 102, the peripheral area 102 surrounding the periphery of the display area 101; the display substrate includes a substrate 1 and a pixel circuit (not shown in the figure), the pixel circuit being disposed on the substrate 1; further including a crack detection circuit 2, disposed on the substrate 1 and located in the peripheral area 102; the crack detection circuit 2 includes a switch circuit 21 and a trace 22, the trace 22 connecting the switch circuit 21 and the pixel circuit to form a loop for detecting whether there is a crack in the peripheral area 102.

[0048] By disposing the crack detection circuit 2 in the peripheral area 102 of the display substrate, when a crack appears in the peripheral area 102, it will cause the crack detection circuit 2 to be open, and then cause the loop formed by the trace 22, the switch circuit 21 and the pixel circuit to be open. According to the display screen phenomenon shown when the crack detection circuit 2 is open, it is determined whether there is a crack in the peripheral area, so as to more conveniently and quickly detect whether there is a crack in the peripheral area 102. Compared with the current method of detecting cracks by detecting the resistance of the trace, it not only improves the detection efficiency, but also makes the detection result more accurate.

[0049] Optionally, the pixel circuit includes a first reference potential terminal 3 and a ground terminal 4; one end of the trace 22 is connected to the first end of the switch circuit 21, and the other end is connected to a detection signal input terminal 5; the second end of the switch circuit 21 is connected to the first reference potential terminal 3; the third end of the switch circuit 21 is connected to the ground terminal 4. Wherein, the switch circuit 21 can realize the connection and disconnection between the first reference potential terminal 3 and the ground terminal 4, and according to the different display screen phenomena of the display substrate when the first reference potential terminal 3 and the ground terminal 4 are connected and disconnected, the detection of cracks in the peripheral area 102 of the display substrate is realized.

[0050] Optionally, the trace 22 winds around the display area 101 at least once. In this embodiment, the trace 22 winds around the display area 101 once (as Figure 5 ) or twice (as Figure 2 and Figure 3 ). Since a crack at any position in the peripheral area 102 will cause the trace 22 at the corresponding position to be disconnected, so setting the trace 22 like this can enable the crack detection circuit 2 to detect cracks at any position in the entire peripheral area 102, preventing missed detection of cracks in the peripheral area 102.

[0051] Optionally, as Figures 2 - 4As shown, the switch circuit 21 includes a first transistor T1 and a second transistor T2; the gate 210 of the first transistor T1 and the gate 210 of the second transistor T2 are connected to one end of the trace 22; the first pole 211 of the first transistor T1 is connected to the first reference potential terminal 3; the second pole 212 of the first transistor T1 is connected to the first pole 211 of the second transistor T2; the second pole 212 of the second transistor T2 is connected to the ground terminal 4. Among them, the trace 22 has two ends. Among them, the first transistor T1 and the second transistor T2 are connected in series and share the gate 210 to form a double-gate structure. In this way, when the switch circuit 21 is turned off and the disconnection between the first reference potential terminal 3 and the ground terminal 4 is realized, the leakage between the first pole 211 and the second pole 212 of the first transistor T1 and the leakage between the first pole 211 and the second pole 212 of the second transistor T2 can be reduced; thus, the crack detection result is more accurate.

[0052] Optionally, the first pole 211 and the second pole 212 of the first transistor T1 are the source and the drain respectively; the first pole 211 and the second pole 212 of the second transistor T2 are the source and the drain respectively.

[0053] Optionally, the first transistor T1 and the second transistor T2 are P-type transistors or N-type transistors. For example, the first transistor T1 and the second transistor T2 are PMOS transistors or NMOS transistors.

[0054] Based on the above structure of the display substrate, this embodiment also provides a method for detecting cracks in the display substrate, as Figures 6 - 8 shown, including: when the display substrate is in the display mode, the detection signal input by the detection signal input terminal 5 turns off the switch circuit 21, and the first reference potential terminal 3 and the ground terminal 4 are open-circuited; when the display substrate is in the detection mode, the detection signal input by the detection signal input terminal 5 turns on the switch circuit 21, and the first reference potential terminal 3 and the ground terminal 4 are short-circuited.

[0055] Optionally, when the display substrate is in the detection mode, when there is a crack in the edge area 102 of the display substrate, an open circuit is formed between the first reference potential terminal 3 and the ground terminal 4, and the display substrate displays a non-yellow normal gray-scale picture; when there is no crack in the edge area 102 of the display substrate, a path is formed between the first reference potential terminal 3 and the ground terminal 4, and the non-yellow picture displayed by the display substrate turns yellow.

[0056] In this embodiment, taking the first transistor T1 and the second transistor T2 as P-type transistors as an example, the specific detection principle of the crack detection circuit 2 for detecting cracks is described. As Figure 6 shown, when the display substrate is in the normal display mode, the signal input by the detection signal input terminal 5 is 7V, that is, the gate voltages of both the first transistor T1 and the second transistor T2 are 7V, and the source of the second transistor T2 is connected to the ground terminal 4, V T2源极= 0V. At this time, the V of the second transistor T2 栅 -V 源 = 7V - 0V = 7V, and the second transistor T2 is turned off; the source of the first transistor T1 is connected to the drain of the second transistor T2, and V T1源极 = 0V. At this time, the V of the first transistor T1 栅 -V 源 = 7V - 0V = 7V, and the first transistor T1 is also turned off; the switch circuit 21 is turned off, the first reference potential terminal 3 and the ground terminal 4 are not short-circuited, the first reference potential terminal 3 works normally, and the non-yellow grayscale image displayed on the display substrate is displayed normally.

[0057] As Figure 7 shown, when the display substrate enters the crack detection mode, the signal input to the detection signal input terminal 5 is -7V. If there is no crack in the edge area 102, the gate voltage V of the first transistor T1 栅 = -7V, the source voltage V 源 = 0V, and the gate-source voltage V 栅 -V 源 = -7V - 0V = -7V, and the first transistor T1 is turned on. Similarly, the second transistor T2 is also turned on, the switch circuit 21 is conducted, the first reference potential terminal 3 and the ground terminal 4 are short-circuited. At this time, the non-yellow grayscale image displayed on the display substrate turns yellow.

[0058] As Figure 8 shown, when the display substrate enters the crack detection mode, the signal input to the detection signal input terminal 5 is -7V. If a crack occurs in the edge area 102, the gate voltage V of the first transistor T1 栅 = 0V, the source voltage V 源 = 0V, and the gate-source voltage V 栅 -V 源 = 0V - 0V = 0V, and the first transistor T1 is turned off. Similarly, the second transistor T2 is also turned off, the switch circuit 21 is not conducted, the first reference potential terminal 3 works normally, and the non-yellow grayscale image displayed on the display substrate is displayed normally. At this time, it can be determined that a crack has occurred in the edge area 102 based on the non-yellow display image.

[0059] Among them, since both the first transistor T1 and the second transistor T2 belong to triodes, and triodes have a microscopic signal amplification effect, it is possible to accurately detect whether a crack has occurred in the edge area 102.

[0060] Optionally, as Figure 9As shown, the switch circuit 21 includes a first transistor T1; the gate of the first transistor T1 is connected to one end of the trace 22; the first pole of the first transistor T1 is connected to the first reference potential terminal 3; the second pole of the first transistor T1 is connected to the ground terminal 4. That is, the switch circuit 21 can be provided with only one transistor, and the connection and disconnection between the first reference potential terminal 3 and the ground terminal 4 are realized by the on and off of one transistor. According to the different phenomena of the display substrate showing the picture when the first reference potential terminal 3 and the ground terminal 4 are connected and disconnected, the detection of cracks in the edge region 102 of the display substrate can be realized. The principle of crack detection by this crack detection circuit 2 is the same as that of the above Figures 6 - 8 in the detection principle.

[0061] It should be noted that the switch circuit 21 can also include more than three transistors, and more than three transistors are connected in the connection manner of the two transistors in the above Figure 2 and Figure 4 , that is, the gates of more than three transistors are connected, and the first poles and second poles of each transistor are connected in series in turn. As long as the switch circuit 21 can realize the function of connecting and disconnecting between the first reference potential terminal 3 and the ground terminal 4 in the crack detection mode.

[0062] Optionally, the pixel circuit further includes a control transistor; the gate 210 of the first transistor T1 and the gate 210 of the second transistor T2 are on the same layer and made of the same material as the gate of the control transistor; the first pole 211 and the second pole 212 of the first transistor T1, the first pole 211 and the second pole 212 of the second transistor T2 are on the same layer and made of the same material as the first pole and the second pole of the control transistor; the active layer 213 of the first transistor T1 and the active layer 213 of the second transistor T2 are on the same layer and made of the same material as the active layer of the control transistor; the trace 22 is on the same layer and made of the same material as the first pole and the second pole of the control transistor. With such a setting, the gates 210, active layers 213, first poles 211 and second poles 212 of the first transistor T1 and the second transistor T2 can be formed simultaneously with the gate, active layer, first pole and second pole of the control transistor respectively through one patterning process, thereby simplifying the process and reducing the preparation process cost.

[0063] Among them, as Figure 4As shown, a first insulating layer 6 is provided between the active layer 213 and the gate 210 of each transistor; a second insulating layer 7 is provided between the gate 210 and the first electrode 211 and the second electrode 212; the second electrode 212 of the first transistor T1 is connected to one end of the active layer 213 through a via hole provided in the first insulating layer 6 and the second insulating layer 7, and the second electrode 212 of the first transistor T1 is connected to a first reference potential terminal 3 provided in the same layer; the first electrode 211 of the second transistor T2 is connected to the other end of the active layer 213 through a via hole provided in the first insulating layer 6 and the second insulating layer 7, and the first electrode 211 of the second transistor T2 is connected to a ground terminal 4 provided in the same layer; the gate 210 of the first transistor T1 and the gate 210 of the second transistor T2 are connected to the wiring 22 through a via hole provided in the second insulating layer 7.

[0064] Optionally, the wiring 22 may also be in the same layer and made of the same material as the gate of the control transistor.

[0065] Optionally, the display substrate further includes a flat layer 8 and a light emitting unit (not shown) disposed on the flat layer 8 on the side away from the substrate 1, and the flat layer 8 is located on the side of the switch circuit 21 away from the substrate 1. The light emitting unit may be an OLED (organic electroluminescent) light emitting unit, which will not be described in detail here.

[0066] Based on the above structure of the display substrate, this embodiment also provides a method for preparing the display substrate, such as Figure 10 As shown, an active layer 213, a first insulating layer 6, a gate 210, a second insulating layer 7, a first electrode 211, a second electrode 212, a wiring 22, a first reference potential terminal 3 and a ground terminal 4, a flat layer 8, and a pattern of a light-emitting unit are sequentially formed on a substrate 1. The specific preparation of each film layer pattern adopts a conventional patterning process, which will not be repeated here.

[0067] The display substrate provided in the embodiment of the present invention sets a crack detection circuit in the edge area of ​​the display substrate. When a crack appears in the edge area, the crack detection circuit will be broken, and then the loop formed by the wiring, the switch circuit and the pixel circuit will be broken. Whether a crack appears in the edge area is determined based on the display picture phenomenon shown when the crack detection circuit is broken, thereby more conveniently and quickly detecting whether a crack appears in the edge area. Compared with the current method of detecting cracks by detecting wiring resistance, not only the detection efficiency is improved, but also the detection result can be made more accurate. In addition, the preparation of the crack detection circuit in the display substrate does not need to add additional steps in the preparation process of the display substrate, saving the preparation process cost.

[0068] An embodiment of the present invention further provides a display panel, comprising the display substrate in the above embodiment.

[0069] By adopting the display substrate in the above embodiments, the display panel can more accurately detect whether there are cracks on the display panel, and at the same time improve the detection efficiency of cracks.

[0070] The display panel provided by the present invention can be any product or component with a display function, such as an OLED panel, an OLED TV, a monitor, a mobile phone, a navigator, etc.

[0071] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A display substrate having a display area and a peripheral area, the peripheral area surrounding the display area; The display substrate includes a substrate and a pixel circuit, and the pixel circuit is disposed on the substrate; It is characterized in that It further includes a crack detection circuit, which is disposed on the substrate and located in the edge area; the crack detection circuit includes a switch circuit and a trace, the trace connects the switch circuit and the pixel circuit to form a loop, and is used to detect whether there is a crack in the edge area; The pixel circuit includes a first reference potential terminal and a ground terminal; One end of the trace is connected to the first end of the switch circuit, and the other end is connected to the detection signal input terminal; The second end of the switch circuit is connected to the first reference potential terminal; the third end of the switch circuit is connected to the ground terminal; The first reference potential terminal is an ELVSS signal.

2. The display substrate according to claim 1, characterized in that The trace winds around the display area at least once.

3. The display substrate according to claim 2, characterized in that The switch circuit includes a first transistor and a second transistor; The gates of the first transistor and the second transistor are connected to one end of the trace; The first pole of the first transistor is connected to the first reference potential terminal; The second pole of the first transistor is connected to the first pole of the second transistor; the second pole of the second transistor is connected to the ground terminal.

4. The display substrate according to claim 2, characterized in that The switch circuit includes a first transistor; The gate of the first transistor is connected to one end of the trace; The first pole of the first transistor is connected to the first reference potential terminal; the second pole of the first transistor is connected to the ground terminal.

5. The display substrate according to claim 3, characterized in that The first transistor and the second transistor are P-type transistors or N-type transistors.

6. The display substrate according to claim 3, characterized in that The pixel circuit further includes a control transistor; The gates of the first transistor and the second transistor are on the same layer and made of the same material as the gate of the control transistor; The first and second poles of the first transistor, the first and second poles of the second transistor are on the same layer and made of the same material as the first and second poles of the control transistor; The active layers of the first transistor and the second transistor are on the same layer and made of the same material as the active layer of the control transistor; The trace is on the same layer and made of the same material as the first and second poles of the control transistor; Alternatively, the trace is on the same layer and made of the same material as the gate of the control transistor.

7. A display panel, characterized in that It includes the display substrate according to any one of claims 1-6.

8. A method for detecting cracks in a display substrate according to any one of claims 1 - 6, characterized in that It includes: When the display substrate is in the display mode, the detection signal input to the detection signal input terminal turns off the switch circuit, and there is an open circuit between the first reference potential terminal and the ground terminal; When the display substrate is in the detection mode, the detection signal input to the detection signal input terminal turns on the switch circuit, and there is a short circuit between the first reference potential terminal and the ground terminal; When the display substrate is in the detection mode, when there is a crack in the edge area of the display substrate, an open circuit is formed between the first reference potential terminal and the ground terminal, and the display substrate displays a non-yellow normal gray-scale picture; When there is no crack in the edge area of the display substrate, a path is formed between the first reference potential terminal and the ground terminal, and the non-yellow picture displayed by the display substrate turns yellow.

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