WO2020098081A1

WO2020098081A1 - Flexible circuit board, display panel, and display device

Info

Publication number: WO2020098081A1
Application number: PCT/CN2018/123380
Authority: WO
Inventors: 黄世帅
Original assignee: 惠科股份有限公司
Priority date: 2018-11-12
Filing date: 2018-12-25
Publication date: 2020-05-22
Also published as: CN109195321B; CN109195321A

Abstract

A flexible circuit board, a display panel, and a display device. The flexible circuit board comprises: a substrate; a bonding lead; a short-circuit trace for connecting an external test pad, the short-circuit trace and the bonding lead being disposed on the same surface of the substrate; an insulation layer covering the short-circuit trace and the bonding lead; and a reserved trace disposed at a side of the insulation layer away from the short-circuit trace and the bonding lead, a projection of the reserved trace on the substrate main component respectively intersecting with the short-circuit trace and the bonding lead.

Description

Flexible circuit board, display panel and display device

This application requires priority to be submitted to the Chinese Patent Office on November 12, 2018, with the application number 201811338858.3 and the application name of the Chinese patent application titled "flexible circuit board, display panel and display device", the entire content of which is incorporated by reference in In this application.

Technical field

The present application relates to the field of display technology, in particular to a flexible circuit board, display panel and display device.

Background technique

The statements here only provide background information related to the present application and do not necessarily constitute prior art. In thin-film transistor liquid crystal displays (Thin Film Transistor-Liquid Crystal) (TFT-LCD), a flip-chip thin film substrate (Chip On Film, COF) is usually used to connect the printed circuit board (PCB) and the liquid crystal panel together , So that the PCB board can output the drive control signal to the liquid crystal panel to complete the corresponding drive control. The COF substrate has bonding leads. One end of the bonding lead is connected to the PCB board, and the other end is connected to the substrate body of the COF substrate.

In the actual production process, the phenomenon of vertical line defects or horizontal line defects often occurs due to poor bonding process. In order to detect the cause of the defect, the traditional method is to remove the COF at the defective location and re-press the other COF. Furthermore, it was determined that the COF or the liquid crystal panel caused the vertical line defect or the horizontal line defect. The traditional detection method requires a dedicated COF laminating machine, and the detection takes a long time, resulting in the low convenience of the traditional COF lamination detection method.

Application content

According to various embodiments of the present application, a flexible circuit board, a display panel, and a display device are provided to solve the problem of low convenience in operation of a conventional method for detecting poor COF compression.

A flexible circuit board, including:

Substrate body

Welding lead

Short-circuit traces, the short-circuit traces and the welding leads are provided on the same surface of the substrate body, and the short-circuit traces are used to connect an external test pad;

An insulating layer, the insulating layer covering the shorted trace and the soldered lead; and

Reserved traces, the reserved traces are provided on the side of the insulating layer away from the short-circuit traces and the welding leads, and the projections of the reserved traces on the substrate body are The short-circuit trace and the soldered lead cross.

A display panel, including:

First substrate

A second substrate, which is opposite to the first substrate;

The dielectric layer is provided between the first substrate and the second substrate;

An adhesive layer provided on the second substrate; and

A flexible circuit board, the flexible circuit board is pressed and connected with the second substrate through the adhesive layer, the flexible circuit board includes: a substrate body; a welding lead; a short connection trace, the short connection The trace and the welding lead are provided on the same surface of the substrate body, the short-circuit trace is used to connect an external test pad; an insulating layer, the insulation layer covers the short-circuit trace and the welding lead; And reserved traces, the reserved traces are provided on a side of the insulating layer away from the short-circuit traces and the welding leads, and the projections of the reserved traces on the substrate body are respectively The short-circuit trace and the soldered lead cross.

A display device includes a backlight module and a display panel. The display panel includes:

First substrate

A second substrate, which is opposite to the first substrate;

An adhesive layer provided on the second substrate; and

The details of one or more embodiments of the application are set forth in the drawings and description below. Other features, objects, and advantages of this application will become apparent from the description, drawings, and claims.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, without paying any creative work, other drawings may be obtained based on these drawings.

1 is a schematic structural view of a flexible circuit board in an embodiment;

2 is a schematic diagram of welding reserved traces, short-circuited traces and welding leads in an embodiment;

3 is a schematic structural view of a flexible circuit board in another embodiment;

4 is a schematic structural view of a flexible circuit board in another embodiment;

5 is a schematic structural view of a flexible circuit board in yet another embodiment;

6 is a schematic structural view of a flexible circuit board in another embodiment;

7 is a schematic view of the structure of a display panel in an embodiment.

detailed description

In order to facilitate understanding of the present application, the present application will be described more fully below with reference to related drawings. The drawings show preferred embodiments of the present application. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

Referring to FIG. 1, a flexible circuit board includes: a substrate body 100; soldering leads 200; short-circuiting traces 300, the shorting traces 300 and the welding leads 200 are disposed on the same surface of the substrate body 100, short-circuiting traces 300 is used to connect the external test pad 500; an insulating layer (not shown), the insulating layer covers the shorted traces and the welding leads; the trace 400 is reserved, and the trace 400 is set on the insulating layer away from the shorted trace 300 and On one side of the soldering lead 200, the projection of the reserved trace 400 on the substrate body 100 crosses the shorting trace 300 and the soldering lead 200, respectively.

Specifically, in the display industry, the circuit board that provides the drive signal is separated from the substrate that displays based on the drive signal. The drive signal is provided by PCBA (Printed Circuit Board Assembly) and connected through a flexible circuit board (ie COF substrate) To the substrate for display; PCBA refers to the circuit board obtained after SMT (Surface Mount Technology) and DIP (Dual Inline-pin Package) plug-in processing. One end of the COF substrate is connected to the PCBA circuit board through the welding lead 200, and the other end is press-connected to the substrate for display through conductive adhesive, so that the drive control signal output from the PCBA circuit board can be transmitted to the substrate, providing the drive control signal for the substrate, Then display the corresponding image. The COF substrate includes a substrate body 100 and soldering leads 200 and shorting traces 300 all provided on the same surface of the substrate body 100, and a reserved trace 400 is provided on a different layer from the soldering lead 200 and the shorting trace 300, The projections of the reserved traces 400 on the substrate body 100 intersect the welding leads 200 and the shorting traces 300, respectively. Please refer to FIG. 2, when the vertical line or the horizontal line is bad due to the crimping process, the reserved trace 400 and the welding lead 200 can be directly soldered to the corresponding intersection point, and the reserved trace 400 and the short circuit can be The position corresponding to the projection intersection point of the line 300 is welded. The position corresponding to the projection intersection point is the pre-corresponding pre-corresponding point when the projection of the reserved trace 400 on the substrate body 100 crosses the short-circuit trace 300 or the welding lead 200. The position corresponding to the left trace 400 and the short-circuit trace 300, or the position corresponding to the reserved trace 400 and the welding lead 200. The shorting trace 300 and the welding lead 200 are connected through the reserved trace 400, so that the signal output from the welding lead 200 can be output to the test pad 500 connected to the shorting trace 300. At this time, the oscilloscope probe can be used to directly detect the output waveform of the drive control signal corresponding to the occurrence of the wire defect, and display it on the oscilloscope. If the detected waveform is abnormal, it means that the cause of the wire defect is the COF substrate; No abnormality is detected in the detected waveform, which means that the COF substrate is working normally, and the cause of the line defect is the internal problem of the display substrate. Using the above method, a reserved trace 400 is provided inside the COF substrate. When a line defect occurs, there is no need to directly remove the COF substrate, which reduces the detection time and effectively avoids the waste of the COF substrate. It should be noted that, in one embodiment, when the reserved trace 400 is welded to the shorting trace 300 or the reserved trace 400 is welded to the welding lead 200, the laser welding method is used.

In one embodiment, the number of reserved traces 400 is two or more. Specifically, taking two reserved traces as an example, please refer to FIG. 2, for convenience of description, the welding leads 200 are sequentially numbered as 210, 220, 230, 240, and 250. The number of short-circuit traces 300 inside the COF substrate There are usually two, the first short-circuit trace 310 and the second short-circuit trace 320, of which the welding lead 220 is the welding lead corresponding to the occurrence of wire defect, and the welding lead 230 is the normal working welding lead. In order to detect the welding lead The reason for the bad line corresponding to 220, welding the welding lead 220 to the position corresponding to the projected intersection of the first reserved trace 410, and the position corresponding to the projected intersection of the first reserved trace 410 and the first shorted trace 310 At the same time, the welding lead 230 is welded to the position corresponding to the projected intersection of the second reserved trace 420, and the position corresponding to the projected intersection of the second reserved trace 420 and the second shorting trace 320 is welded. Enables signal transmission between the welding lead 220 and the first shorting trace 310, and outputs the corresponding signal to the test pad 500 connected to the first shorting trace 310, and the welding lead 230 and the second shorting trace 320 Signal transmission is performed, and the corresponding signal is output to the test pad 500 connected to the second shorting trace 320. Then output the corresponding signal waveform to the oscilloscope through the oscilloscope probe and display it respectively. By comparing and analyzing the two output waveforms, it is determined whether the cause of the line defect is the COF substrate. If they are consistent, it is not the line defect caused by the COF substrate. If they do not match, it is a line defect caused by the COF substrate. It should be noted that in one embodiment, the two output waveforms can be displayed on the same oscilloscope, which is convenient for comparative analysis of the waveforms; in another embodiment, two oscilloscopes can also be used to display the correspondence between different welding leads. Waveform, to avoid interference between the two waveform signals, resulting in low accuracy of the detection results, the specific way to display the waveform, you can choose according to the actual situation. In one embodiment, the oscilloscope may be preset to have a normal output signal waveform corresponding to the welding lead. As long as the welding lead corresponding to the defective wire is welded to the reserved trace, the signal waveform is output to the oscilloscope for comparative analysis. However, in this embodiment, there is no need to weld the welding leads and reserved wiring corresponding to the normal conditions, which has the advantage of simple operation.

It can be understood that the number of welding leads 200 corresponding to simultaneous line defects may be multiple, that is, there are multiple vertical or horizontal lines that are defective. In this case, in one embodiment, a plurality of corresponding settings of the trace 400 are provided. In order to ensure that each welding lead 200 corresponding to a defective wire can be welded with the corresponding reserved trace 400, and the signal is output to the test pad 500 for detection and analysis; it should be noted that in this embodiment, there is also The normal working welding lead 200 is welded to the reserved trace 400, and the reserved trace 400 is welded to the corresponding shorting trace 300, and the normal working waveform is output for comparison with the waveform of the welding lead 200 corresponding to the bad wire. . In another embodiment, multiple reserved traces 400 may be provided. When only one line is defective, the corresponding welding lead 200 is welded to the reserved trace 400, and the trace 300 is shorted to the reserved trace Welding line 400; simultaneously welding multiple welding leads 200 corresponding to normal work with different reserved traces 400 simultaneously, outputting multiple waveforms corresponding to normal conditions, and then comparing and analyzing the waveforms corresponding to abnormal conditions, can also detect whether It is a defective wire caused by the COF substrate. By setting multiple reserved traces 400, not only can the detection of multiple defective lines be achieved, but also the accuracy of the detection can be effectively improved.

Referring to FIG. 2, in one embodiment, the short-circuit trace 300 includes a main line, and the projection of the reserved trace 400 on the substrate body 100 crosses the main line of the short-circuit trace 300.

Specifically, the welding leads 200 are divided into odd-numbered welding leads and even-numbered welding leads according to the arrangement position, and the odd-numbered and even-numbered columns of pixel signals can be controlled separately by the odd-numbered welding leads and the even-numbered welding leads, which is convenient for testing and identification. In the production process, the welding leads 200 are respectively connected to the branch lines of the short-circuit trace 300. Before the COF substrate is pressed and connected to the substrate for display, the branch line of the short-circuit trace 300 is laser cut The connection of the soldering lead 200 is cut off to avoid the mutual influence of the signals when the subsequent COF substrate provides drive control signals to the surface, resulting in abnormal display. The projection of the reserved trace 400 on the substrate body 100 crosses the main line of the short-circuited trace 300 and the welding lead 400 respectively. When a wire defect occurs, the corresponding welding lead 200 can be directly connected to the reserved trace 400 For soldering, the reserved trace 400 is welded to the main line of the shorted trace 300, so that the output signal can be transmitted to the test pad 500 connected to the shorted trace 300 via the main line of the shorted trace 300, thereby detecting the cause of the defect.

Please continue to refer to FIG. 2. In one embodiment, the shorting trace 300 includes a first shorting trace 310 and a second shorting trace 320, and the reserved trace 400 includes a first reserved trace 410 and a second The reserved trace 420, the projection of the first reserved trace 410 on the substrate body 100 crosses the main line of the first shorted trace 310, and the projection of the second reserved trace 420 on the substrate body 100 and the second short The main line connecting the line 320 crosses.

Specifically, the number of shorting traces 300 is two, which are the first shorting trace 310 and the second shorting trace 320 respectively, and the number of reserved traces 400 is also two, which are respectively reserved for the first The trace 410 and the second reserved trace 420. In this embodiment, the first reserved trace 410 and the second reserved trace 420 are in the same direction so that the projections on the substrate body 100 are the same as the corresponding short The main line of the connecting trace 300 crosses, that is, the projection of the first reserved trace 410 on the substrate body 100 crosses the main line of the first shorting trace 310, and the projection of the second reserved trace 420 on the substrate body 100 The main lines of the second short-circuit trace 320 cross. When a wire defect occurs, the corresponding welding lead 200 is welded to the first reserved trace 410, the first reserved trace 410 is welded to the main line of the first short-circuit trace 310, and any set of normal working vertical lines Or the welding lead 200 corresponding to the horizontal line is welded to the second reserved trace 420, the second reserved trace 420 is welded to the main line of the second short-circuit trace 320, and the signal waveform is output to the oscilloscope for comparative analysis.

Further, in one embodiment, please refer to FIG. 3, the first reserved trace 410 and the second reserved trace 420 may also be projected on the substrate body 100 and shorted to the trace 300 from different directions The main line crosses, for example, the projection of the first reserved trace 410 on the substrate body 100 extends in the first direction as shown in FIG. 3, and then crosses the main line of the first shorted trace 310, and the second reserved trace The projection of 420 on the substrate body 100 extends in a second direction opposite to the first direction, and then crosses the main line of the second short-circuit trace 320, and the same detection result can also be achieved.

Referring to FIG. 4, in one embodiment, the shorting trace 300 includes a branch line, and the projection of the reserved trace 400 on the substrate body 100 crosses the branch line of the shorting trace 300.

Specifically, the short-circuit trace 300 includes a branch line. When the projection of the reserved trace 400 on the substrate body 100 crosses the short-circuit trace 300, it can also directly cross the branch line, and can also output the signal to the corresponding test The pad 500 is used to analyze the cause of the defect. The specific analysis process is similar to the projection of the reserved trace 400 on the substrate body 100 and the main line crossing of the shorted trace 300, which will not be repeated here.

Please continue to refer to FIG. 4. In one embodiment, the shorting trace 300 includes a first shorting trace 310 and a second shorting trace 320, and the reserved trace 400 includes a first reserved trace 410 and a second The reserved trace 420, the projection of the first reserved trace 410 on the substrate body 100 crosses the branch line of the first shorted trace 310, and the projection of the second reserved trace 420 on the substrate body 100 and the second short Branches that take the line 320 cross. Similarly, taking two shorted traces 300 and two reserved traces 400 as an example, the main line and the branch of the shorted trace 300 are connected to each other, and the projection of the reserved trace 400 and the shorted trace 300 is projected After the welding at the intersection point, the waveform corresponding to the signal can also be output to the oscilloscope for comparative analysis. The specific process is similar to the connection between the two preset traces and the main line of the short-circuited trace 300, which will not be repeated here. It should be noted that, in one embodiment, please refer to FIG. 5, the projections of the first reserved trace 410 and the second reserved trace 420 on the substrate body 100 may also be realized by short-circuiting from different directions The branch lines of the line 300 cross, for example, the projection of the first reserved trace 410 on the substrate body 100 extends in the first direction as shown in FIG. 5, and then crosses the branch line of the first short-circuit trace 310, and the second reserved The projection of the trace 420 on the substrate body 100 extends in a second direction opposite to the first direction, and then crosses the branch line of the second short-circuit trace 320, and the same detection result can also be achieved.

Further, referring to FIG. 6, in one embodiment, the shorting trace 300 includes a main line and a branch line, and the shorting trace 300 includes a first shorting trace 310 and a second shorting trace 320, and the trace is reserved 400 includes a first reserved trace 410 and a second reserved trace 420, the projection of the first reserved trace 410 on the substrate body 100 crosses the main line of the first short-circuit trace 310, and the second reserved trace The projection of 420 on the substrate body 100 crosses the branch line of the second shorting trace 320. Specifically, the main line and the branch line of the shorted trace 300 are connected to each other. After welding the position corresponding to the projected intersection of the branch line of the shorted trace 300 and the shorted trace 300, the corresponding waveform of the signal can also be output to the oscilloscope A comparative analysis is performed. The specific process is similar to the projection of the above two reserved traces 400 on the substrate body 100 and the main line crossing of the shorted trace 300, which will not be repeated here.

The above-mentioned flexible circuit board is provided with reserved traces, and the projection of the reserved traces on the substrate body crosses the short-circuit trace and the welding lead respectively. The short-circuit trace is used to connect the external test pad. In the case of the situation, it is only necessary to directly weld the corresponding welding leads to the reserved traces, and at the same time weld the reserved traces and the shorted traces, so that the corresponding signals are output to the outside through the reserved traces and the shorted traces The test pad analyzes and judges, and then obtains the cause of the bad straight line. Compared with the traditional detection method, it does not require the removal of the flexible circuit board, which effectively reduces the detection time, and has the advantage of high operation convenience when performing line defect analysis.

7, a display panel includes a first substrate 20; a second substrate 30, which is disposed opposite to the first substrate 20; a dielectric layer 40, which is disposed between the first substrate 20 and the second substrate 30; an adhesive layer 50 and the above-mentioned flexible circuit board 10, the adhesive layer 50 is provided on the second substrate 30, and the flexible circuit board 10 is pressed and connected to the second substrate 30 through the adhesive layer 50. It can be understood that the flexible circuit board 10 may specifically be the flexible circuit board described in any of the above embodiments, and the specific structure has been explained in detail in the above embodiments, and will not be repeated here.

Specifically, in the display industry, the circuit board that provides the driving signal is separated from the substrate that displays according to the driving signal. The driving signal is provided by the PCBA, and is connected to the substrate that performs the display via the flexible circuit board (ie, COF substrate); Among them, PCBA refers to the circuit board obtained after processing through SMT upload and DIP plug-in. One end of the COF substrate is connected to the PCBA circuit board through the welding lead 200, and the other end is press-connected to the substrate for display through conductive adhesive, so that the drive control signal output from the PCBA circuit board can be transmitted to the substrate, providing the drive control signal for the substrate, Then display the corresponding image. The COF substrate includes a substrate body 100 and soldering leads 200 and shorting traces 300 all provided on the same surface of the substrate body 100, and a reserved trace 400 is provided on a different layer from the soldering lead 200 and the shorting trace 300, The projections of the reserved traces 400 on the substrate body 100 intersect the welding leads 200 and the shorting traces 300, respectively. Please refer to FIG. 2, when the vertical line or the horizontal line is bad due to the crimping process, the reserved trace 400 and the welding lead 200 can be directly soldered to the corresponding intersection point, and the reserved trace 400 and the short circuit can be The position corresponding to the projection intersection point of the line 300 is welded. The position corresponding to the projection intersection point is the pre-corresponding pre-corresponding point when the projection of the reserved trace 400 on the substrate body 100 crosses the short-circuit trace 300 or the welding lead 200. The position corresponding to the left trace 400 and the short-circuit trace 300, or the position corresponding to the reserved trace 400 and the welding lead 200. The shorting trace 300 and the welding lead 200 are connected through the reserved trace 400, so that the signal output from the welding lead 200 can be output to the test pad 500 connected to the shorting trace 300. At this time, the oscilloscope probe can be used to directly detect the output waveform of the drive control signal corresponding to the occurrence of the wire defect, and display it on the oscilloscope. If the detected waveform is abnormal, it means that the cause of the wire defect is the COF substrate; No abnormality is detected in the detected waveform, which means that the COF substrate is working normally, and the cause of the line defect is the internal problem of the display substrate. Using the above method, a reserved trace 400 is provided inside the COF substrate. When a line defect occurs, there is no need to directly remove the COF substrate, which reduces the detection time and effectively avoids the waste of the COF substrate.

It should be noted that in one embodiment, the first substrate 20 is a color filter substrate, the second substrate 30 is an array substrate, the dielectric layer 40 is a liquid crystal layer, and the adhesive layer 50 is ACF (Anisotropic Conductive Film). Film) conductive adhesive layer. Color filter is a kind of optical filter substrate that expresses color. It can accurately select the light passing through a certain wavelength range and reflect the light of other wavelengths. The basic structure of the color film substrate is composed of a glass substrate (Glass Substrate), a black matrix (Black Matrix), a color layer (Color Layer), a protective layer (Over Coat) and an ITO conductive film. Liquid crystal refers to the fact that after the molten state or the solvent is dissolved, the rigidity of the solid substance is lost, and the fluidity of the liquid is obtained, and the anisotropic order of the molecules of some crystalline substances is retained, forming a kind of crystal and Substances in the liquid state that are intermediate in nature. A dielectric layer 40 formed by liquid crystal molecules is arranged between the array substrate and the color filter substrate. When the power is turned on, the dielectric layer 40 is turned on and the arrangement becomes orderly, so that the light passes easily; when the power is not turned on, the arrangement is disordered to prevent the light from passing.

In one embodiment, the display panel is a twisted nematic display panel (Twisted Nematic, TN panel). It can be understood that, in other embodiments, it may also be other types of display panels, for example, IPS panel (In-Pane Swinging, plane switching), VA panel (Multi-domain Vertica Aignment, multi-quadrant vertical alignment), etc. can.

The above display panel is provided with reserved traces on the flexible circuit board, and the projection of the reserved traces on the substrate body crosses the short-circuited trace and the welding lead respectively. The short-circuited trace is used to connect the external test pad. When a bad wire condition occurs, it is only necessary to directly weld the corresponding welding leads to the reserved traces, and at the same time to weld the reserved traces and short-circuit traces, so that the corresponding signals pass through the reserved traces and short-circuit traces Output to the external test pad for analysis and judgment, and then obtain the cause of the straight line failure. Compared with the traditional detection method, it does not require the removal of the flexible circuit board, which effectively reduces the detection time, and has the advantage of high operation convenience when performing line defect analysis.

A display device includes a backlight module and the above display panel. It can be understood that the display panel may specifically be the display panel described in any of the foregoing embodiments, and the specific structure has been explained in detail in the foregoing embodiments, and will not be repeated here.

Specifically, in the display industry, the circuit board that provides the driving signal is separated from the substrate that displays according to the driving signal. The driving signal is provided by the PCBA, and is connected to the substrate that performs the display via the flexible circuit board (ie, COF substrate); Among them, PCBA refers to the circuit board obtained after processing through SMT upload and DIP plug-in. One end of the COF substrate is connected to the PCBA circuit board through the welding lead 200, and the other end is press-connected to the substrate for display through conductive adhesive, so that the drive control signal output from the PCBA circuit board can be transmitted to the substrate, providing the drive control signal for the substrate, Then display the corresponding image. Referring to FIG. 1, the COF substrate includes a substrate body 100 and soldering leads 200 and short-circuiting traces 300 that are both disposed on the same surface of the substrate body 100, and pre-positions are provided on different layers from the soldering lead 200 and the shorting traces 300. The trace 400 is left, and the projection of the reserved trace 400 on the substrate body 100 intersects the solder wire 200 and the short-circuit trace 300 respectively. Please refer to FIG. 2, when the vertical line or the horizontal line is bad due to the crimping process, the reserved trace 400 and the welding lead 200 can be directly soldered to the corresponding intersection point, and the reserved trace 400 and the short circuit can be The position corresponding to the projection intersection point of the line 300 is welded. The position corresponding to the projection intersection point is the pre-corresponding pre-corresponding point when the projection of the reserved trace 400 on the substrate body 100 crosses the short-circuit trace 300 or the welding lead 200. The position corresponding to the left trace 400 and the short-circuit trace 300, or the position corresponding to the reserved trace 400 and the welding lead 200. The shorting trace 300 and the welding lead 200 are connected through the reserved trace 400, so that the signal output from the welding lead 200 can be output to the test pad 500 connected to the shorting trace 300. At this time, the oscilloscope probe can be used to directly detect the output waveform of the drive control signal corresponding to the occurrence of the wire defect, and display it on the oscilloscope. If the detected waveform is abnormal, it means that the cause of the wire defect is the COF substrate; No abnormality is detected in the detected waveform, which means that the COF substrate is working normally, and the cause of the line defect is the internal problem of the display substrate. Using the above method, a reserved trace 400 is provided inside the COF substrate. When a line defect occurs, there is no need to directly remove the COF substrate, which reduces the detection time and effectively avoids the waste of the COF substrate.

In one embodiment, the display device further includes a first polarizer disposed on the side of the second substrate away from the dielectric layer, and a second polarizer disposed on the side of the first substrate away from the dielectric layer.

Specifically, the dielectric layer is a liquid crystal layer. The liquid crystal material is placed between two pieces of transparent conductive glass attached with a polarizer with a vertical optical axis. The liquid crystal molecules are distributed parallel to the transparent conductive glass when no voltage is applied, and the two pieces of transparent The conductive glass is respectively arranged with alignment films oriented perpendicular to each other, and the liquid crystal molecules are sequentially arranged in accordance with the direction of the fine grooves of the alignment film. If no electric field is applied, the light enters from the second polarizer, and the polarization direction is in accordance with the arrangement of the liquid crystal molecules It can be emitted from the first polarizer by rotating 90 degrees, and it is in the bright state at this time. If after two pieces of conductive glass are energized, an electric field will be formed between the two pieces of conductive glass, which will affect the arrangement of liquid crystal molecules between them. When the voltage is large enough, the molecules are arranged vertically along the electric field, the polarization direction of the light does not change, and the light cannot penetrate , And then the light source is blocked, so that a dark state is formed when voltage is applied.

In one embodiment, the backlight module is an edge-lit backlight module. Specifically, the edge-lit backlight module means that the light source (Edge) is disposed on the side of the light guide plate, and the light guide plate illuminates the light evenly behind the liquid crystal panel. The design of the edge-lit backlight module makes the display device have the advantages of light weight, thin, narrow frame and low power consumption. It can be understood that, in other embodiments, the backlight module may also be a direct type backlight module or a hollow type backlight module, as long as it can provide a corresponding light source for the display device.

In the above display device, the flexible circuit board is provided with reserved traces, and the projection of the reserved traces on the substrate body crosses the short-circuit trace and the welding lead respectively. The short-circuit trace is used to connect the external test pad when the When a bad wire condition occurs, it is only necessary to directly weld the corresponding welding leads to the reserved traces, and at the same time to weld the reserved traces and short-circuit traces, so that the corresponding signals pass through the reserved traces and short-circuit traces Output to the external test pad for analysis and judgment, and then obtain the cause of the straight line failure. Compared with the traditional detection method, it does not require the removal of flexible circuit boards, which effectively reduces the detection time, and has the advantage of high operation convenience when performing line defect analysis.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To simplify the description, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered within the scope of this description.

The above-mentioned embodiments only express several implementation manners of the present application, and their descriptions are more specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all fall within the protection scope of the present application. Therefore, the protection scope of the patent of this application shall be subject to the appended claims.

Claims

A flexible circuit board, including:

Substrate body

Welding lead

Short-circuit traces, the short-circuit traces and the welding leads are provided on the same surface of the substrate body, and the short-circuit traces are used to connect an external test pad;

An insulating layer, the insulating layer covering the shorted trace and the soldered lead; and

Reserved traces, the reserved traces are provided on the side of the insulating layer away from the short-circuit traces and the welding leads, and the projections of the reserved traces on the substrate body are The short-circuit trace and the soldered lead cross.
The flexible circuit board according to claim 1, wherein the number of the reserved traces is two or more.
The flexible circuit board according to claim 1, wherein the short-circuit trace includes a main line, and a projection of the reserved trace on the substrate body crosses the main line of the short-circuit trace.
The flexible circuit board according to claim 3, wherein the shorting trace includes a first shorting trace and a second shorting trace, and the reserved trace includes a first reserved trace and a first Two reserved traces, the projection of the first reserved trace on the substrate body crosses the main line of the first shorted trace, and the second reserved trace on the substrate body The projection crosses the main line of the second short-circuited trace.
The flexible circuit board according to claim 4, wherein the first reserved trace and the second reserved trace are respectively projected on the substrate body and the corresponding The main line of the short circuit is crossed.
The flexible circuit board according to claim 4, wherein the first reserved trace and the second reserved trace are respectively projected on the substrate body and the corresponding The main line of the short circuit is crossed.
The flexible circuit board according to claim 1, wherein the short-circuit trace includes a branch line, and a projection of the reserved trace on the substrate body crosses the branch line of the short-circuit trace.
The flexible circuit board according to claim 7, wherein the shorting trace includes a first shorting trace and a second shorting trace, and the reserved trace includes a first reserved trace and a first Two reserved traces, the projection of the first reserved trace on the substrate body crosses the branch line of the first shorted trace, and the second reserved trace on the substrate body The projection crosses the branch line of the second short-circuit trace.
The flexible circuit board according to claim 8, wherein the first reserved trace and the second reserved trace are respectively projected on the substrate body and the corresponding The spurs shorting the trace cross.
The flexible circuit board according to claim 8, wherein the first reserved trace and the second reserved trace are respectively projected on the substrate body and the corresponding The spurs shorting the trace cross.
The flexible circuit board according to claim 1, wherein the shorting trace includes a main line and a branch line, the shorting trace includes a first shorting trace and a second shorting trace, the reserved The trace includes a first reserved trace and a second reserved trace, the projection of the first reserved trace on the substrate body crosses the main line of the first short-circuit trace, and the second The projection of the reserved trace on the substrate body crosses the branch line of the second short-circuit trace.
A display panel including:

First substrate

A second substrate, which is opposite to the first substrate;

The dielectric layer is provided between the first substrate and the second substrate;

An adhesive layer provided on the second substrate; and

The flexible circuit board according to any one of claims 1-11.
The display panel according to claim 12, wherein the first substrate is a color filter substrate, the second substrate is an array substrate, the dielectric layer is a liquid crystal layer, and the adhesive layer is an easily conductive conductive adhesive film layer.
The display panel according to claim 12, wherein the display panel is a twisted nematic display panel.
A display device comprising a backlight module and the display panel according to claim 12 or 13.
The display device according to claim 15, wherein the display device further comprises a first polarizer disposed on a side of the second substrate away from the dielectric layer, and a first polarizer disposed on the first substrate away from the medium The second polarizer on the side of the layer.
The display device according to claim 15, wherein the backlight module is an edge-lit backlight module.