Display panel, manufacturing method of display panel and electronic equipment

Abstract

The embodiment of the invention provides a display panel, a manufacturing method of the display panel and electronic equipment, the display panel comprises a bending display area, the bending display area is provided with a bending axis, a plurality of first thin film transistors are arranged on the bending display area, each first thin film transistor comprises a first source electrode and a first drain electrode, and the first source electrode is arranged on the bending axis. A first conducting channel is formed between the first source electrode and the first drain electrode of each first thin film transistor, and the included angle between the direction of the first conducting channel and the bending axis is smaller than 90 degrees; wherein the total length of each part of the first conducting channel in the direction of the first conducting channel is greater than the total length of each part of the first conducting channel in any other direction. According to the display panel, the display brightness difference between the bending display area and the non-bending display area can be reduced.

Description

[0001] This application is a divisional case of the Chinese patent application submitted to the State Intellectual Property Office of China on October 20, 2020, with application number 2020111243727 and application name "Display panel, method for manufacturing display panel and electronic device". All contents of this application are included in the parent case. Technical Field

[0002] The present application relates to the field of display technology, and in particular to a display panel, a method for manufacturing a display panel, and an electronic device. Background Art

[0003] Flexible displays refer to displays that can be bent, curved, folded, or rolled up without significant damage and are made using thin, flexible substrates, unlike flat panel displays.

[0004] With the increasing number of flexible displays, active-matrix organic light-emitting diode (AMOLED) display panels based on low-temperature polycrystalline silicon (LTPS) are gaining widespread application. However, when LTPS-based flexible displays are bent, a brightness difference exists between the bent and non-bent display areas. This difference in brightness increases with the display time of the bent display area. Summary of the Invention

[0005] The present application provides a display panel, a method for manufacturing a display panel, and an electronic device to reduce the difference in display brightness between a bent display area and a non-bent display area.

[0006] In the first aspect, the present application provides a display panel, comprising a bending display area, the bending display area having a bending axis, a plurality of first thin film transistors being arranged on the bending display area, each of the first thin film transistors comprising a first source and a first drain, a first conductive channel being formed between the first source and the first drain of each first thin film transistor, and an angle formed between the direction of the first conductive channel and the bending axis being less than 90 degrees; wherein the total length of each part of the first conductive channel in the direction of the first conductive channel is greater than the total length of each part of the first conductive channel in any other direction.

[0007] The above-mentioned display panel sets the direction of the first conductive channel of the first thin film transistor in the bent display area to form an angle less than 90 degrees with the bending axis, so that the angle between the direction of the first conductive channel and the strain direction of the first conductive channel is not 0 degrees. Compared with when the direction of the first conductive channel is parallel to the strain direction of the first conductive channel, the strain along the direction of the first conductive channel of the first conductive channel is reduced, the carrier mobility in the first conductive channel changes less, the turn-on current of the first thin film transistor changes less, the driving current of the bent display area changes less, and the difference in display brightness between the bent display area and the non-bent display area is reduced, thereby improving the display effect of the display panel.

[0008] In a possible design, when the display panel is bent so that the first thin film transistor is subjected to compressive strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 0 degrees to 5 degrees.

[0009] In one possible design, the angle between the first conductive channel of the first thin-film transistor and the bending axis is 0 degrees. Through the solution provided by this embodiment, the compressive strain applied to the first conductive channel is perpendicular to the first conductive channel direction, the length of the first conductive channel in the first conductive channel direction does not change with changes in the amount of compressive strain applied to the first conductive channel, and the carrier mobility in the first conductive channel does not change with changes in the amount of compressive strain applied to the first conductive channel. Consequently, the turn-on current of the first thin-film transistor does not change with changes in the amount of compressive strain applied to the first conductive channel, the drive current of the bent display area is the same as the drive current of the non-bent display area, and the display brightness of the bent display area is consistent with that of the non-bent display area.

[0010] In one possible design, when the display panel is bent and causes the first thin-film transistor to be subjected to tensile strain, the angle formed between the direction of the first conductive channel of the first thin-film transistor and the bending axis is 65 to 75 degrees. Through the solution provided in this embodiment, the angle formed between the direction of the first conductive channel of the first thin-film transistor and the bending axis is set to 65 to 75 degrees, the tensile strain experienced by the first conductive channel is mostly perpendicular to the direction of the first conductive channel, the length of the first conductive channel in the first conductive channel direction changes less with the tensile strain experienced by the first conductive channel, the carrier mobility in the first conductive channel changes less with the tensile strain experienced by the first conductive channel, and thus the turn-on current of the first thin-film transistor changes less with the tensile strain experienced by the first conductive channel, the driving current of the bent display area differs less from that of the non-bent display area, and the display brightness of the bent display area differs less from that of the non-bent display area.

[0011] In one possible design, the curved display area is further provided with a plurality of second thin-film transistors, each of which includes a second source and a second drain. A second conductive channel is formed between the second source and the second drain of each second thin-film transistor, and the direction of the second conductive channel is consistent with the direction of the first conductive channel. The total length of the portions of the second conductive channel in the second conductive channel direction is greater than the total length of the portions of the second conductive channel in any other direction. Through the solution provided in this embodiment, the direction of the second conductive channel of the second thin-film transistors in the curved display area is set to be the same as the direction of the first conductive channel, thereby simplifying the manufacturing process of the thin-film transistors of the display panel and saving costs.

[0012] In a possible design, both the first thin film transistor and the second thin film transistor are low-temperature polysilicon thin film transistors.

[0013] In one possible design, a non-bending display area is further included, and a plurality of third thin-film transistors are arranged on the non-bending display area, each of the third thin-film transistors includes a third source and a third drain, and a third conductive channel is formed between the third source and the third drain of each third thin-film transistor, and the direction of the third conductive channel is inconsistent with the direction of the first conductive channel, wherein the total length of each part of the third conductive channel in the direction of the third conductive channel is greater than the total length of each part of the third conductive channel in any other direction.

[0014] In one possible design, a non-bending display area is further included, wherein a plurality of third thin-film transistors are disposed on the non-bending display area, each of the third thin-film transistors including a third source and a third drain, a third conductive channel being formed between the third source and the third drain of each of the third thin-film transistors, and the direction of the third conductive channel being consistent with the direction of the first conductive channel, wherein the total length of the portions of the third conductive channel in the direction of the third conductive channel is greater than the total length of the portions of the third conductive channel in any other direction. Through the solution provided in this embodiment, the direction of the third conductive channel of the third thin-film transistors in the non-bending display area is set to be the same as the direction of the first conductive channel, thereby simplifying the manufacturing process of the thin-film transistors of the display panel and saving costs.

[0015] In a possible design, the third thin film transistor is a low-temperature polysilicon thin film transistor.

[0016] In a second aspect, the present application provides an electronic device comprising the display panel described in the first aspect.

[0017] In a third aspect, the present application provides a method for manufacturing a display panel, comprising:

[0018] Providing a substrate, wherein the substrate includes a bending display area, and the bending display area has a bending axis;

[0019] forming a buffer layer on the substrate;

[0020] Depositing an amorphous silicon thin film on the buffer layer, performing a polycrystallization process on the amorphous silicon thin film to form a polycrystalline silicon thin film, and performing a patterning process on the polycrystalline silicon thin film to form an active layer located on the buffer layer;

[0021] forming a gate insulating layer on the patterned active layer;

[0022] forming a first metal layer on the gate insulating layer, and patterning the first metal layer to form a gate located above the active layer;

[0023] In which, in the process of forming the gate, ion implantation is performed on the active layer so that the active layer includes a first conductive channel, a first source region and a first drain region, the first conductive channel is formed between the first source region and the first drain region, the angle between the direction of the first conductive channel and the bending axis is less than 90 degrees, and the total length of each part of the first conductive channel in the direction of the first conductive channel is greater than the total length of each part of the first conductive channel in any other direction.

[0024] In the above-mentioned method for manufacturing a display panel, when manufacturing the first thin film transistor in the bent display area of the display panel, the direction of the first conductive channel of the first thin film transistor in the bent display area is set to an angle less than 90 degrees with the bending axis, so that the angle between the direction of the first conductive channel and the strain direction of the first conductive channel is not 0 degrees. Compared with when the direction of the first conductive channel is parallel to the strain direction of the first conductive channel, the strain along the direction of the first conductive channel of the first conductive channel is reduced, the carrier mobility in the first conductive channel changes less, the turn-on current of the first thin film transistor changes less, the driving current of the bent display area changes less, and the difference in display brightness between the bent display area and the non-bent display area is reduced, thereby improving the display effect of the display panel.

[0025] In one possible design, it also includes:

[0026] forming a gate dielectric layer on the patterned first metal layer;

[0027] forming an interlayer insulating layer on the gate dielectric layer;

[0028] forming a first via hole and a second via hole, wherein the first via hole and the second via hole expose the first source region and the first drain region respectively;

[0029] A patterned source-drain metal layer is formed, and the first source and the first drain are overlapped. The source-drain metal layer includes the first source and the first drain.

[0030] In a possible design, when the bending of the substrate causes the first conductive channel to be subjected to compressive strain, the angle formed between the direction of the first conductive channel and the bending axis is 0 degrees to 5 degrees.

[0031] In a possible design, the angle formed between the direction of the first conductive channel and the bending axis is 0 degree.

[0032] In a possible design, when the bending of the substrate causes the first conductive channel to be subjected to tensile strain, the angle formed between the direction of the first conductive channel and the bending axis is 65 degrees to 75 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A graph showing the change in carrier mobility versus compressive strain in an existing thin film transistor;

[0034] Figure 2 A graph showing the variation of carrier mobility with tensile strain in an existing thin film transistor;

[0035] Figure 3 A schematic structural diagram of a display panel provided in one embodiment of the present application;

[0036] Figure 4 A schematic diagram of a first source, a first drain, and a first conductive channel provided in one embodiment of the present application;

[0037] Figure 5 A schematic diagram of a first source, a first drain, and a first conductive channel provided in another embodiment of the present application;

[0038] Figure 6 A graph showing changes in carrier mobility versus compressive strain in a first thin film transistor provided in an embodiment of the present application;

[0039] Figure 7 A graph showing the variation of carrier mobility with tensile strain in a first thin film transistor provided in an embodiment of the present application;

[0040] Figure 8 A flowchart of a method for manufacturing a display panel provided in one embodiment of the present application;

[0041] Figure 9 A cross-sectional view of a display panel provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0042] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to facilitate a more thorough and comprehensive understanding of the disclosure of the present application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0044] Thin-film transistors are categorized as polycrystalline silicon (p-Si) TFTs and amorphous silicon (a-Si) TFTs. The difference between the two lies in their transistor properties. The molecular structure of p-Si TFTs is neatly and directionally arranged within a single grain, resulting in electron mobility 200-300 times faster than that of the more chaotically arranged a-Si TFTs. p-Si primarily includes high-temperature polycrystalline silicon (HTPS) and low-temperature polycrystalline silicon (LTPS).

[0045] LTPS technology is a process applicable to the next generation of TFT displays. It primarily transforms a-Si thin film into p-Si thin film through excimer laser annealing, metal optimized crystallization, or solid-phase crystallization. LTPS TFT displays offer faster response times and higher resolution, resulting in superior image quality. Using LTPS technology in the formation of display peripheral circuits reduces the number of integrated circuits, simplifies the display's periphery, and ultimately achieves narrow-bezel technology.

[0046] Flexible displays are screens that can be bent, curved, folded, or rolled up without significant damage and are made using thin, flexible substrates, unlike flat-panel displays. In recent years, advances in new materials and technologies have made the application of flexible displays in electronic devices a reality. Flexible displays are used in a variety of applications, including e-paper, e-books, televisions, computers, PDAs, automotive displays, tablets, smartphones, and wearable devices.

[0047] With the increasing number of flexible display screens, active-matrix organic light-emitting diode (AMOLED) display panels based on LTPS have been widely used. However, during the bending process of the LTPS-based flexible display screen, there will be a brightness difference between the bent display area and the non-bent display area. The applicant found that when the LTPS TFT is subjected to compressive strain, the carrier mobility of the LTPS TFT increases (such as 0.3‰ compressive strain can cause the carrier mobility to increase by 10%), and the turn-on current of the LTPS TFT increases. The increase in the turn-on current of the LTPS TFT will cause the driving current of the bent display area to increase, thereby increasing the brightness of the screen; when the LTPS TFT is subjected to tensile strain, the carrier mobility of the LTPS TFT decreases (0.3‰ tensile strain can cause the carrier mobility to decrease by 2% to 5%), the turn-on current of the LTPS TFT decreases, and the increase in the turn-on current of the LTPS TFT will cause the driving current of the bent display area to decrease, thereby reducing the brightness of the screen. Furthermore, as the display time of the curved display area increases, the difference between the display brightness of the curved display area and the display brightness of the non-curved display area becomes greater.

[0048] A thin film transistor generally includes a source electrode and a drain electrode, and a conductive channel is formed between the source electrode and the drain electrode. Figure 1 The graph is a graph showing the change in carrier mobility in the thin film transistor with the amount of compressive strain applied to the thin film transistor when the thin film transistor is subjected to compressive strain and the direction of the compressive strain is parallel to the direction of the conductive channel. Figure 1 It can be seen that when a thin film transistor is subjected to compressive strain and the direction of the compressive strain is parallel to the conductive channel direction, the carrier mobility in the thin film transistor increases as the amount of compressive strain applied to the thin film transistor increases. The total length of the conductive channel portions in the conductive channel direction is greater than the total length of the conductive channel portions in any other direction.

[0049] Figure 2 The graph is a graph showing the change of carrier mobility in the thin film transistor with the amount of tensile strain applied to the thin film transistor when the thin film transistor is subjected to tensile strain and the direction of the tensile strain is parallel to the direction of the conductive channel. Figure 2 It can be seen that when the thin film transistor is subjected to tensile strain and the direction of the tensile strain is parallel to the direction of the conductive channel, the carrier mobility in the thin film transistor decreases as the tensile strain increases.

[0050] Please refer to Figures 3 to 5An embodiment of the present application provides a display panel, including a bending display area 20, wherein the bending display area 20 has a bending axis 21. A plurality of first thin film transistors 22 are provided on the bending display area 20. Each first thin film transistor 22 includes a first source electrode 222 and a first drain electrode 224, and a first conductive channel 226 is formed between the first source electrode 222 and the first drain electrode 224 of each first thin film transistor 22. The angle formed between the first conductive channel direction s and the bending axis 21 is less than 90 degrees. The total length of each part of the first conductive channel 226 in the first conductive channel direction s is greater than the total length of each part of the first conductive channel 226 in any other direction.

[0051] For a scrollable display panel, the scrollable display panel has a length and a width. The scrollable display panel can be rolled along a bending axis in the length direction, with the bending axis being perpendicular to the length direction of the scrollable display panel. In this case, each region of the display panel along the length direction can be bent, and each region of the display panel is a bendable display region 20. Alternatively, the scrollable display panel can be rolled along a bending axis in the width direction, with the bending axis being perpendicular to the width direction of the scrollable display panel. In this case, each region of the display panel along the width direction can be bent, and each region of the display panel is a bendable display region 20.

[0052] For a foldable display panel, the bendable display area 20 only occupies a portion of the display panel and has a length and a width. The foldable display panel can be folded in the length direction along a bending axis that is perpendicular to the length of the foldable display panel. Alternatively, the foldable display panel can be folded in the width direction along a bending axis that is perpendicular to the width of the foldable display panel.

[0053] It should be noted that, regardless of whether it is a rollable display panel or a foldable display panel, the bending axis of the display panel is fixed.

[0054] The bending display area 20 is the area where stress and strain are generated in the various structures within the display panel when the display panel is bent along the bending axis 21. The strain direction of the various structures within the display panel is perpendicular to the bending axis 21. The various structures specifically refer to that the display panel includes a substrate and thin film transistors and pixels formed on the substrate. The projection of the first conductive channel 226 on the substrate can be curved or straight. Since the angle between the first conductive channel direction s and the bending axis 21 is less than 90 degrees, the angle between the first conductive channel direction s and the strain direction of the first conductive channel 226 is not 0 degrees, that is, the first conductive channel direction s and the strain direction of the first conductive channel 226 are not parallel to each other. Figure 4 and Figure 5 The first direction x is the direction of strain on the first thin film transistor 22 , and the second direction y is parallel to the bending axis 21 .

[0055] The mobility represents the speed at which carriers move in the first conductive channel 226 between the first source 222 and the first drain 224. When the first conductive channel 226 is subjected to strain along the first conductive channel direction s, the length of the first conductive channel 226 in the first conductive channel direction s changes. When the first conductive channel direction s is parallel to the strain direction of the first thin film transistor 22, the strain on the first conductive channel 226 along the first conductive channel direction s is the greatest, and the length change of the first conductive channel 226 in the first conductive channel direction s is the greatest. When the first conductive channel 226 is subjected to compressive strain along the first conductive channel direction s, the length of the first conductive channel 226 in the first conductive channel direction s decreases; when the first conductive channel 226 is subjected to tensile strain along the first conductive channel direction s, the length of the first conductive channel 226 in the first conductive channel direction s increases.

[0056] When the first conductive channel direction s of the first thin film transistor 22 is not parallel to the strain direction of the first thin film transistor 22, compared with when the first conductive channel direction s is parallel to the strain direction of the first thin film transistor 22, the strain on the first conductive channel 226 along the first conductive channel direction s is reduced, the length change of the first conductive channel 226 in the first conductive channel direction s is reduced, and the change in carrier mobility in the first conductive channel 226 is reduced.

[0057] The display panel may further include a non-bending display area, and the display brightness of the non-bending display area is not affected by the bending of the bent display area 20 .

[0058] The display panel of the embodiment of the present application sets the first conductive channel direction s of the first thin film transistor 22 in the bending display area 20 to form an angle less than 90 degrees with the bending axis 21, so that the angle between the first conductive channel direction s and the strain direction of the first conductive channel 226 is not 0 degrees. Compared with when the first conductive channel direction s is parallel to the strain direction of the first conductive channel 226, the strain along the first conductive channel direction s of the first conductive channel 226 is reduced, the carrier mobility in the first conductive channel 226 changes less, the turn-on current of the first thin film transistor 22 changes less, the driving current of the bending display area 20 changes less, and the difference in display brightness between the bending display area 20 and the non-bending display area is reduced, thereby improving the display effect of the display panel.

[0059] In one embodiment, when the display panel is bent and causes the first thin film transistor 22 in the bent display area 20 to be subjected to compressive strain, the angle formed between the first conductive channel direction s of the first thin film transistor 22 and the bending axis 21 is 0 degrees to 5 degrees. Preferably, when the angle formed between the first conductive channel direction s of the first thin film transistor 22 and the bending axis 21 is 0 degrees, the compressive strain experienced by the first conductive channel 226 is perpendicular to the first conductive channel direction s, the length of the first conductive channel 226 in the first conductive channel direction s does not change with changes in the amount of compressive strain experienced by the first conductive channel 226, and the carrier mobility in the first conductive channel 226 does not change with changes in the amount of compressive strain experienced by the first conductive channel 226. As a result, the turn-on current of the first thin film transistor 22 does not change with changes in the amount of compressive strain experienced by the first conductive channel 226. The driving current of the bent display area 20 is the same as that of the non-bending display area, and the display brightness of the bent display area 20 and the non-bending display area is consistent.

[0060] It can be understood that when the angle between the first conductive channel direction s and the bending axis 21 is 0 degrees, the angle between the first conductive channel direction s and the compressive strain on the first conductive channel 226 is 90 degrees. When the angle between the first conductive channel direction s and the bending axis 21 is 45 degrees, the angle between the first conductive channel direction s and the compressive strain on the first conductive channel 226 is 45 degrees. When the angle between the first conductive channel direction s and the bending axis 21 is 90 degrees, the angle between the first conductive channel direction s and the compressive strain on the first conductive channel 226 is 0 degrees.

[0061] See also Figure 6 , Figure 6 This is a graph showing how the carrier mobility in the first thin film transistor 22 changes with the amount of compressive strain provided in one embodiment of the present application, specifically when the first thin film transistor 22 is subjected to compressive strain and the angles between the direction of the compressive strain and the direction s of the first conductive channel are 0 degrees, 45 degrees, and 90 degrees, respectively. Figure 6It can be seen that when the angle formed between the first conductive channel direction s and the compressive strain applied to the first conductive channel 226 is 0 degrees, the carrier mobility in the first conductive channel 226 increases with the increase in the compressive strain applied to the first conductive channel 226. When the angle formed between the first conductive channel direction s and the compressive strain applied to the first conductive channel 226 is 45 degrees, the carrier mobility in the first conductive channel 226 increases with the increase in the compressive strain applied to the first conductive channel 226. When the compressive strain applied to the first conductive channel 226 changes by the same amount, the change in carrier mobility in the first conductive channel 226 is greater when the angle formed between the first conductive channel direction s and the compressive strain applied to the first conductive channel 226 is 0 degrees than when the angle formed between the first conductive channel direction s and the compressive strain applied to the first conductive channel 226 is 45 degrees. When the angle formed between the first conductive channel direction s and the compressive strain on the first conductive channel 226 is 90 degrees, the carrier mobility in the first conductive channel 226 does not substantially change with the change in the compressive strain on the first conductive channel 226 .

[0062] In one embodiment, when the display panel is bent and the first thin film transistor 22 in the bent display area 20 is subjected to tensile strain, the angle formed between the first conductive channel direction s of the first thin film transistor 22 and the bending axis 21 is 65 degrees to 75 degrees. When the bending of the display panel causes the first thin film transistor 22 of the bent display area 20 to be subjected to tensile strain, the angle between the first conductive channel direction s of the first thin film transistor 22 and the bending axis 21 is set to 65 degrees to 75 degrees, and the tensile strain borne by the first conductive channel 226 is mostly perpendicular to the first conductive channel direction s. The length of the first conductive channel 226 in the first conductive channel direction s changes little with the tensile strain borne by the first conductive channel 226, and the carrier mobility in the first conductive channel 226 changes little with the tensile strain borne by the first conductive channel 226. Therefore, the turn-on current of the first thin film transistor 22 changes little with the tensile strain borne by the first conductive channel 226, the driving current of the bent display area 20 is less different from that of the non-bending display area, and the display brightness of the bent display area 20 and the non-bending display area is less different.

[0063] It can be understood that when the angle between the first conductive channel direction s and the bending axis 21 is 65 degrees to 75 degrees, the angle between the first conductive channel direction s and the tensile strain on the first conductive channel 226 is 15 degrees to 25 degrees. When the angle between the first conductive channel direction s and the bending axis 21 is 90 degrees, the angle between the first conductive channel direction s and the tensile strain on the first conductive channel 226 is 0 degrees. When the angle between the first conductive channel direction s and the bending axis 21 is 45 degrees, the angle between the first conductive channel direction s and the tensile strain on the first conductive channel 226 is 45 degrees. When the angle between the first conductive channel direction s and the bending axis 21 is 0 degrees, the angle between the first conductive channel direction s and the tensile strain on the first conductive channel 226 is 90 degrees.

[0064] See also Figure 7 , Figure 7 This is a graph showing how the carrier mobility in the first thin film transistor 22 changes with the amount of tensile strain provided in one embodiment of the present application. Specifically, it is a graph showing how the carrier mobility in the first thin film transistor 22 changes with the amount of tensile strain when the first thin film transistor 22 is subjected to tensile strain and the angles between the direction of the tensile strain and the direction s of the first conductive channel are 0 degrees, 15 degrees to 25 degrees, 45 degrees, and 90 degrees, respectively. Figure 7 It can be seen that when the angle formed between the first conductive channel direction s and the tensile strain applied to the first conductive channel 226 is 0 degrees, the carrier mobility in the first conductive channel 226 decreases as the tensile strain applied to the first conductive channel 226 increases. When the angle formed between the first conductive channel direction s and the tensile strain applied to the first conductive channel 226 is 45 degrees, the carrier mobility in the first conductive channel 226 increases as the tensile strain applied to the first conductive channel 226 increases. When the angle formed between the first conductive channel direction s and the tensile strain applied to the first conductive channel 226 is 90 degrees, the carrier mobility in the first conductive channel 226 increases as the tensile strain applied to the first conductive channel 226 increases. When the angle between the first conductive channel direction s and the tensile strain applied to the first conductive channel 226 is 15 to 25 degrees, the carrier mobility in the first conductive channel 226 remains substantially unchanged as the tensile strain applied to the first conductive channel 226 changes.

[0065] In one embodiment, a plurality of second thin film transistors are further provided on the curved display area, each second thin film transistor includes a second source and a second drain, a second conductive channel is formed between the second source and the second drain of each second thin film transistor, and the direction of the second conductive channel is consistent with the direction s of the first conductive channel, wherein the total length of each part of the second conductive channel in the direction of the second conductive channel is greater than the total length of each part of the second conductive channel in any other direction.

[0066] A first thin-film transistor 22 can form a 2T1C structure TFT drive circuit with two second thin-film transistors and a capacitor. A first thin-film transistor 22 can also form a 6T1C structure TFT drive circuit with six second thin-film transistors and a capacitor. A first thin-film transistor 22 can also form a 7T1C structure TFT drive circuit with seven second thin-film transistors and a capacitor. Or a first thin-film transistor 22 can also form a 5T2C structure TFT drive circuit with five second thin-film transistors and two capacitors, and so on. A TFT drive circuit is used to drive a sub-pixel to emit light. The second thin-film transistor of the above-mentioned TFT drive circuit serves as a switching thin-film transistor, which is used to control whether current enters the drive circuit. The first thin-film transistor 22 serves as a driving thin-film transistor, which is connected to the power supply voltage and provides drive current to the sub-pixel for a certain period of time.

[0067] By setting the direction of the second conductive channel of the second thin film transistor in the bent display area to be the same as the direction s of the first conductive channel, the manufacturing process of the thin film transistor of the display panel can be simplified, thereby saving costs.

[0068] In other embodiments, the second conductive channel direction may also be different from the first conductive channel direction s.

[0069] Please refer to Figure 1 In one embodiment, a plurality of third thin-film transistors 42 are disposed on the non-bent display area 40. Each third thin-film transistor 42 includes a third source and a third drain, with a third conductive channel formed between the third source and the third drain of each third thin-film transistor 42. The direction of the third conductive channel is inconsistent with the direction s of the first conductive channel, wherein the total length of the third conductive channel portions in the third conductive channel direction is greater than the total length of the third conductive channel portions in any other direction. The third thin-film transistors 42 include switching thin-film transistors and driving thin-film transistors.

[0070] In one embodiment, a plurality of third thin-film transistors 42 are disposed on the non-bent display area 40. Each third thin-film transistor 42 includes a third source and a third drain, with a third conductive channel formed between the third source and the third drain of each third thin-film transistor 42. The direction of the third conductive channel is consistent with the direction s of the first conductive channel, wherein the total length of the third conductive channel portions in the third conductive channel direction is greater than the total length of the third conductive channel portions in any other direction. The third thin-film transistors 42 include switching thin-film transistors and driving thin-film transistors.

[0071] In this embodiment, by setting the third conductive channel direction of the third thin film transistor 42 in the non-bending display area 40 to be the same as the first conductive channel direction s, the manufacturing process of the thin film transistor of the display panel can be simplified and the cost can be saved.

[0072] The first thin film transistor 22, the second thin film transistor, and the third thin film transistor 42 are all polysilicon thin film transistors. Furthermore, the first thin film transistor 22, the second thin film transistor, and the third thin film transistor 42 are all low-temperature polysilicon thin film transistors. The use of low-temperature polysilicon thin film transistors can enable the flexible screen including the above-mentioned display panel to have advantages such as high mobility, fast response speed, high resolution, high brightness, and high aperture ratio.

[0073] An embodiment of the present application further provides an electronic device, comprising a display screen, wherein the display screen comprises the display panel described in any of the above embodiments. The electronic device may be an e-book, a television, a computer, a PDA, a car display, a tablet computer, a smartphone, a wearable device, or the like.

[0074] Please refer to Figure 8 The present application also provides a method for manufacturing a display panel, specifically a method for manufacturing a first thin film transistor in a curved display area, comprising the following steps:

[0075] Step S10: providing a substrate 50, wherein the substrate includes a bending display area having a bending axis. The substrate 50 may be a polymer plastic substrate or other suitable materials.

[0076] Please also refer to Figure 9 , step S20 , forming a buffer layer 51 on the substrate 50 .

[0077] Specifically, the buffer layer 51 can be deposited by physical vapor deposition, chemical vapor deposition, or plasma-assisted chemical vapor deposition. The material of the buffer layer 51 can be silicon oxide (SiOX), silicon nitride (SiNx), or a combination of the two. The buffer layer 51 can be a single-layer or multi-layer structure. When the buffer layer 51 is a single-layer structure, its material can be, for example, silicon oxide (SiOX) or silicon nitride (SiNx). When the buffer layer 51 is a two-layer or more structure, it can be a composite film layer of a silicon oxide layer and a silicon nitride layer.

[0078] In step S30 , an amorphous silicon thin film is deposited on the buffer layer 51 , and the amorphous silicon thin film is polycrystallized to form a polycrystalline silicon thin film, and the polycrystalline silicon thin film is patterned to form an active layer 52 on the buffer layer 51 .

[0079] For example, the amorphous silicon film may be deposited on the buffer layer 51 by using plasma enhanced chemical vapor deposition (PECVD) to deposit a layer of amorphous silicon film on the buffer layer 51. The amorphous silicon film is then subjected to a dehydrogenation process in a high-temperature oven to prevent hydrogen explosion during crystallization and reduce the defect state density within the film after crystallization. After the dehydrogenation process is completed, a low-temperature polysilicon process is performed to crystallize the amorphous silicon film using a crystallization method such as laser annealing (ELA), metal-induced crystallization (MIC), or solid-phase crystallization (SPC), thereby forming the active layer 52 on the buffer layer 51.

[0080] Alternatively, an amorphous silicon thin film can be deposited on the substrate having the buffer layer 51 formed thereon. A patterning process is first performed to form a retained pattern in a predetermined area. The retained pattern is then polycrystallized to form a channel region pattern. The patterning process includes steps such as masking, exposure, development, etching, and photoresist stripping.

[0081] In step S40 , a gate insulating layer 53 is formed on the patterned active layer 52 .

[0082] The material of the gate insulating layer 53 may include at least one of silicon oxide and silicon nitride.

[0083] In step S50 , a first metal layer is formed on the gate insulating layer 53 , and the first metal layer is patterned to form a gate 54 located above the active layer 52 .

[0084] During the formation of gate 54, ion implantation is performed on active layer 52, so that active layer 52 includes a first conductive channel, a first source region, and a first drain region. The first conductive channel is formed between the first source region and the first drain region. The angle between the first conductive channel and the bending axis is less than 90 degrees. The total length of the first conductive channel portions in the first conductive channel direction is greater than the total length of the first conductive channel portions in any other direction.

[0085] When the first source region and the first drain region do not distinguish between lightly doped regions and heavily doped regions, after forming the gate 54, ion implantation can be performed on the active layer 52 with the gate 54 as a barrier, so that the active layer 52 includes a first conductive channel, a first source region and a first drain region located on both sides of the first conductive channel.

[0086] When the first source region and the first drain region include a lightly doped region and a heavily doped region, a half-tone mask can be used to expose the photoresist when forming the gate 54. The completely retained portion of the photoresist covers the region corresponding to the gate 54, the partially retained portion of the photoresist covers the region corresponding to the lightly doped region to be formed in the polysilicon film, and the portion where the photoresist is not retained covers the region corresponding to the heavily doped region to be formed in the polysilicon film. In this way, after the photoresist is developed, ion implantation can be performed on the exposed polysilicon film to form the heavily doped region. Then, an ashing process is performed to remove the partially retained portion of the photoresist, and the exposed first metal layer is etched to form the gate 54. Then, using the gate 54 as a barrier, ion implantation is performed on the exposed active layer 52 to form a lightly doped region in addition to the heavily doped region and the first conductive channel corresponding to the gate 54.

[0087] The material of the gate 54 may be, for example, molybdenum (Mo), aluminum (Al) / molybdenum, copper (Cu), etc.

[0088] Step S60 , forming a gate dielectric layer 56 on the patterned first metal layer.

[0089] The material of the gate dielectric layer 56 may be, for example, silicon nitride.

[0090] Step S70 , forming an interlayer insulating layer 58 on the gate dielectric layer 56 .

[0091] The material of the interlayer insulating layer 58 may be silicon nitride, for example.

[0092] In step S80 , a first via hole 61 and a second via hole 62 are formed. The first via hole 61 and the second via hole 62 expose the first source region and the first drain region respectively.

[0093] The first via hole 61 and the second via hole 62 may be formed simultaneously or separately by using a wet etching process or a plasma dry etching process.

[0094] In step S90 , a patterned source-drain metal layer 64 is formed, and the first source and the first drain are overlapped. The source-drain metal layer 64 includes the first source and the first drain.

[0095] The source / drain metal layer 64 may be made of, for example, Mo, Al / Mo, Cu, etc.

[0096] The above-mentioned method for manufacturing the display panel is also applicable to the manufacture of the second thin film transistor in the bent display area and the third thin film transistor on the non-bent display area of the display panel, and each step of the manufacturing process of the second thin film transistor in the bent display area and the third thin film transistor on the non-bent display area can be carried out simultaneously with the corresponding manufacturing process of the first thin film transistor on the bending area, which will not be repeated here.

[0097] After the TFT of the display panel is manufactured, the method for manufacturing the display panel may further include:

[0098] A passivation layer and a planarization layer are formed in sequence; an indium tin oxide semiconductor transparent conductive layer is formed; a pixel definition layer is formed and pattern definition is performed; and a display panel is formed by evaporation packaging.

[0099] In the manufacturing method of the display panel of the embodiment of the present application, when manufacturing the first thin film transistor of the bent display area of the display panel, the direction of the first conductive channel of the first thin film transistor in the bent display area is set to an angle less than 90 degrees with the bending axis, so that the angle between the first conductive channel direction and the strain direction of the first conductive channel is not 0 degrees. Compared with when the first conductive channel direction is parallel to the strain direction of the first conductive channel, the strain along the first conductive channel direction of the first conductive channel is reduced, the carrier mobility in the first conductive channel changes less, the turn-on current of the first thin film transistor changes less, the driving current of the bent display area changes less, and the difference in display brightness between the bent display area and the non-bent display area is reduced, thereby improving the display effect of the display panel.

[0100] In one embodiment, when the bending of the substrate causes the first conductive channel to be subjected to compressive strain, the angle formed between the direction of the first conductive channel and the bending axis is 0 degrees to 5 degrees. Preferably, when the angle formed between the direction of the first conductive channel and the bending axis is 0 degrees, the compressive strain on the first conductive channel is perpendicular to the direction of the first conductive channel, the length of the first conductive channel in the direction of the first conductive channel does not change with the change in the amount of compressive strain on the first conductive channel, the carrier mobility in the first conductive channel does not change with the change in the amount of compressive strain on the first conductive channel, and thus the turn-on current of the first thin film transistor does not change with the change in the amount of compressive strain on the first conductive channel, the driving current of the bent display area is the same as the driving current of the non-bent display area, and the display brightness of the bent display area is consistent with that of the non-bent display area.

[0101] In one embodiment, when the bending of the substrate causes the first conductive channel to be subjected to tensile strain, the angle formed between the direction of the first conductive channel and the bending axis is 65 degrees to 75 degrees. When the bending of the substrate causes the first conductive channel to be subjected to tensile strain, the angle formed between the direction of the first conductive channel and the bending axis is set to 65 degrees to 75 degrees, the tensile strain applied to the first conductive channel is mostly perpendicular to the direction of the first conductive channel, the length of the first conductive channel in the direction of the first conductive channel changes less with the tensile strain applied to the first conductive channel, the carrier mobility in the first conductive channel changes less with the tensile strain applied to the first conductive channel, and thus the turn-on current of the first thin film transistor changes less with the tensile strain applied to the first conductive channel, the driving current of the bent display area is less different from that of the non-bent display area, and the display brightness difference between the bent display area and the non-bent display area is less.

[0102] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A display panel, characterized in that: The invention comprises a bending display area, wherein the bending display area has a bending axis, and a plurality of first thin film transistors are arranged on the bending display area, each of the first thin film transistors comprises a first source and a first drain, a first conductive channel is formed between the first source and the first drain of each first thin film transistor, and the angle formed between the direction of the first conductive channel and the bending axis is less than 90 degrees; wherein the total length of each part of the first conductive channel in the direction of the first conductive channel is greater than the total length of each part of the first conductive channel in any other direction.

2. The display panel according to claim 1, wherein When the display panel is bent so that the first thin film transistor is subjected to compressive strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 0 degrees to 45 degrees.

3. The display panel according to claim 1 or 2, wherein: When the display panel is bent so that the first thin film transistor is subjected to compressive strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 0 degrees to 5 degrees.

4. The display panel according to any one of claims 1 to 3, wherein: An angle formed between a direction of a first conductive channel of the first thin film transistor and the bending axis is 0 degree.

5. The display panel according to claim 1, wherein When the display panel is bent so that the first thin film transistor is subjected to tensile strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 45 degrees to 75 degrees.

6. The display panel according to claim 1 or 5, wherein: When the display panel is bent so that the first thin film transistor is subjected to tensile strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 65 degrees to 75 degrees.

7. The display panel according to any one of claims 1 to 6, wherein: A plurality of second thin film transistors are also provided on the bent display area, each of the second thin film transistors includes a second source and a second drain, a second conductive channel is formed between the second source and the second drain of each second thin film transistor, and the direction of the second conductive channel is consistent with the direction of the first conductive channel, wherein the total length of the parts of the second conductive channel in the direction of the second conductive channel is greater than the total length of the parts of the second conductive channel in any other direction.

8. The display panel according to claim 7, wherein: The first thin film transistor and the second thin film transistor are both low-temperature polysilicon thin film transistors.

9. The display panel according to any one of claims 1 to 8, wherein: It also includes a non-bending display area, on which a plurality of third thin film transistors are arranged, each of the third thin film transistors including a third source and a third drain, a third conductive channel being formed between the third source and the third drain of each of the third thin film transistors, and a direction of the third conductive channel being inconsistent with a direction of the first conductive channel, wherein a total length of each portion of the third conductive channel in the direction of the third conductive channel is greater than a total length of each portion of the third conductive channel in any other direction.

10. The display panel according to any one of claims 1 to 8, wherein: The present invention also includes a non-bending display area, on which a plurality of third thin film transistors are arranged, each of which includes a third source and a third drain, and a third conductive channel is formed between the third source and the third drain of each third thin film transistor, and the direction of the third conductive channel is consistent with the direction of the first conductive channel, wherein the total length of each part of the third conductive channel in the direction of the third conductive channel is greater than the total length of each part of the third conductive channel in any other direction.

11. The display panel according to claim 9 or 10, wherein: The third thin film transistor is a low-temperature polysilicon thin film transistor.

12. An electronic device, characterized in that: The display panel comprises the display panel according to any one of claims 1 to 11.

13. A method for manufacturing a display panel, characterized in that: include: Providing a substrate, wherein the substrate includes a bending display area, and the bending display area has a bending axis; forming a buffer layer on the substrate; Depositing an amorphous silicon thin film on the buffer layer, performing a polycrystallization process on the amorphous silicon thin film to form a polycrystalline silicon thin film, and performing a patterning process on the polycrystalline silicon thin film to form an active layer located on the buffer layer; forming a gate insulating layer on the patterned active layer; forming a first metal layer on the gate insulating layer, and patterning the first metal layer to form a gate located above the active layer; In which, in the process of forming the gate, ion implantation is performed on the active layer so that the active layer includes a first conductive channel, a first source region and a first drain region, the first conductive channel is formed between the first source region and the first drain region, the angle between the direction of the first conductive channel and the bending axis is less than 90 degrees, and the total length of each part of the first conductive channel in the direction of the first conductive channel is greater than the total length of each part of the first conductive channel in any other direction.

14. The method for manufacturing a display panel according to claim 13, wherein: Also includes: forming a gate dielectric layer on the patterned first metal layer; forming an interlayer insulating layer on the gate dielectric layer; forming a first via hole and a second via hole, wherein the first via hole and the second via hole expose the first source region and the first drain region respectively; A patterned source-drain metal layer is formed, and the first source and the first drain are overlapped. The source-drain metal layer includes the first source and the first drain.

15. The method for manufacturing a display panel according to claim 13 or 14, wherein: When the display panel is bent so that the first thin film transistor is subjected to compressive strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 0 degrees to 45 degrees.

16. The method for manufacturing a display panel according to any one of claims 13 to 15, wherein: When the bending of the substrate causes the first conductive channel to be subjected to compressive strain, an angle formed between the direction of the first conductive channel and the bending axis is 0 degrees to 5 degrees.

17. The method for manufacturing a display panel according to any one of claims 13 to 16, wherein: The angle formed between the direction of the first conductive channel and the bending axis is 0 degree.

18. The method for manufacturing a display panel according to any one of claims 13 to 16, wherein: When the display panel is bent so that the first thin film transistor is subjected to tensile strain, an angle formed between a first conductive channel direction of the first thin film transistor and the bending axis is 45 degrees to 75 degrees.

19. The method for manufacturing a display panel according to any one of claims 13 to 16, wherein: When the bending of the substrate causes the first conductive channel to be subjected to tensile strain, the angle formed between the direction of the first conductive channel and the bending axis is 65 degrees to 75 degrees.

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