Display substrate and manufacturing method therefor, and mask and display apparatus
By designing an array of concave electrode structures and using photomask lithography, the problems of luminous efficiency and uniformity in OLED display products have been solved, achieving higher luminous efficiency and uniformity, which is suitable for OLED display devices.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- BOE TECHNOLOGY GROUP CO LTD
- Filing Date
- 2026-01-04
- Publication Date
- 2026-07-30
AI Technical Summary
OLED display products suffer from low luminous efficiency and low luminous uniformity.
The design incorporates multiple light-emitting structures arranged in an array. The side of the first electrode furthest from the substrate is concave, with the depth of the concave surface gradually increasing along a certain direction. A photoresist is used to control the formation of the corresponding concave electrode structure, and the driving circuit and power line design are combined to ensure consistent voltage drop.
It improves the luminous efficiency and uniformity of OLED display products, reduces the area occupied by redundant traces, enables narrow bezel design, and improves the uniformity of carrier contact area and current density.
Smart Images
Figure CN2026070170_30072026_PF_FP_ABST
Abstract
Description
A display substrate, its manufacturing method, a photomask, and a display device.
[0001] Cross-reference of related applications
[0002] This application claims priority to Chinese Patent Application No. 202510104897.0, filed on January 22, 2025, with the State Intellectual Property Office of the People's Republic of China, entitled "A display substrate and its manufacturing method, a mask, and a display device", the entire contents of which are incorporated herein by reference. Technical Field
[0003] This disclosure relates to the field of display technology, and in particular to a display substrate and its manufacturing method, a photomask, and a display device. Background Technology
[0004] Organic light-emitting diode (OLED) displays are widely used in various display products due to their advantages such as low energy consumption, high brightness, and good luminous efficiency.
[0005] However, OLED display products suffer from low luminous efficiency and low luminous uniformity. Summary of the Invention
[0006] This disclosure provides a display substrate and its manufacturing method, a photomask, and a display device to solve the problems of low luminous efficiency and low luminous uniformity in existing OLED display products.
[0007] In a first aspect, to solve the above-mentioned technical problems, embodiments of this disclosure provide a display substrate, including:
[0008] Substrate;
[0009] Multiple light-emitting structures are arranged in an array. Each light-emitting structure includes a first electrode and a light-emitting layer. The first electrode is located between the substrate and the light-emitting layer. The first surface of the first electrode away from the substrate includes a concave surface, which is located within the pixel area corresponding to the light-emitting structure. The second surface of the first electrode close to the substrate is a plane.
[0010] The concave depth of the first electrodes arranged along a first direction gradually increases; wherein, the first direction is the direction from one side of the array to the opposite side of the array, and the power supply for the first electrode is located on the opposite side, or the first direction is the direction from the center of the array to the power supply, and the power supply is located on one side and the opposite side of the array.
[0011] One possible implementation, the first surface, includes:
[0012] The concave surface and the sub-surface connected to the edge of the concave surface;
[0013] The sub-face surrounds the concave surface and is parallel to the second face.
[0014] In one possible implementation, the first surface further includes:
[0015] A transition surface connects the concave surface and the sub-surface, allowing for a smooth transition between the concave surface and the sub-surface.
[0016] One possible implementation, the concave surface includes:
[0017] The bottom surface and the side surface surrounding the bottom surface, wherein the bottom surface is a plane and the side surface is an arc surface, and the bottom surface and the side surface are smoothly transitioned.
[0018] One possible implementation includes a longitudinal cross-sectional view of the concave surface, comprising:
[0019] Circular arc or elliptical arc.
[0020] In one possible implementation, the resistance of the first resistors arranged along the first direction gradually increases.
[0021] In one possible implementation, the roughness of the concave surface is greater than or equal to 1 nm and less than or equal to 10 nm.
[0022] In one possible implementation, the display substrate further includes:
[0023] The driving circuit is connected to the first electrode;
[0024] The power source;
[0025] A power supply line is connected between the voltage and the driving circuit; when the driving circuit drives the light-emitting structure to emit light, the power supply provides power to the first electrode through the driving circuit and the power supply line.
[0026] The total resistance of each first electrode and its corresponding power line is within the error range of the preset resistance value.
[0027] Secondly, embodiments of this disclosure provide a photomask, comprising:
[0028] Multiple exposure structures arranged in an array, each exposure structure including at least an exposure adjustment structure, wherein the light transmittance through the exposure adjustment structure gradually decreases or increases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure; the exposure adjustment structure is used to form a concave surface of a first electrode in the display substrate as described in the first aspect.
[0029] One possible implementation of the exposure adjustment structure includes:
[0030] An incident surface and an exit surface; light rays enter the exposure adjustment structure from the incident surface and exit from the exit surface;
[0031] At least one of the incident surface and the exit surface has an arc surface, and the end of the arc surface closest to the central region is closest to the light source corresponding to the light, so that the light incident on the exposure adjustment structure is mainly focused on the photoresist covering the central region.
[0032] In one possible implementation, both the exit surface and the incident surface have arc surfaces, and the exit surface is parallel to the incident surface;
[0033] Alternatively, the incident surface is a plane, and the exit surface has an arc surface;
[0034] In one possible implementation, the incident surface has an arc surface, and the exit surface is a plane.
[0035] In one possible implementation, the longitudinal cross-sectional shape of the exposure adjustment structure is rectangular;
[0036] In the direction from the center region of the exposure adjustment structure to the edge of the exposure adjustment structure, the light transmittance of the exposure adjustment structure gradually decreases or increases.
[0037] In one possible implementation, the exposure structure further includes a light-blocking structure surrounding the exposure adjustment structure; wherein, when the longitudinal cross-sectional shape of the exposure adjustment structure is rectangular, the light transmittance of the exposure adjustment structure gradually decreases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure.
[0038] The photomask also includes a fully transparent structure surrounding the exposure structure.
[0039] In one possible implementation, the first exposure structure further includes a full exposure structure surrounding the exposure adjustment structure; wherein, when the longitudinal cross-sectional pattern of the exposure adjustment structure is rectangular, the light transmittance of the exposure adjustment structure gradually increases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure.
[0040] The photomask also includes a light-blocking structure, which surrounds the exposure structure.
[0041] Thirdly, embodiments of this disclosure provide a method for manufacturing a display substrate, comprising:
[0042] A conductive layer is deposited on one side of the substrate.
[0043] A photoresist layer is formed on the side of the conductive layer away from the substrate.
[0044] A mask as described in the second aspect is provided on the side of the photoresist away from the substrate, and the photoresist is patterned using the mask so that the side of the photoresist away from the substrate has a plurality of concave surfaces arranged in an array.
[0045] A pattern of photoresist including the plurality of concave surfaces is transferred to the conductive layer to obtain a plurality of first electrodes; the first surface of the first electrode away from the substrate includes a concave surface, and the second surface of the first electrode close to the substrate is a plane; the depth of the concave surfaces of the first electrodes arranged along a first direction gradually increases; wherein, the first direction is the direction from one side of the array to the opposite side, and the power supply for the first electrode is located on the opposite side, or the first direction is the direction from the center of the array to the power supply, and the power supply is located on one side and the opposite side of the array;
[0046] On the side of the plurality of first electrodes away from the substrate, a light-emitting layer corresponding to each first electrode is formed; wherein, the light-emitting structure includes the first electrode and the corresponding light-emitting layer.
[0047] Fourthly, embodiments of this disclosure provide a display device, including a display substrate as described in the first aspect. Attached Figure Description
[0048] Figure 1 is a schematic diagram of the formation of an anode in a related technology;
[0049] Figure 2 is a schematic diagram of the structure of a display substrate provided in an embodiment of this disclosure;
[0050] Figure 3 is a schematic diagram of another display substrate provided in an embodiment of this disclosure;
[0051] Figure 4 is a schematic diagram of the structure of a first electrode provided in an embodiment of this disclosure;
[0052] Figure 5 is a schematic diagram of another first electrode provided in an embodiment of this disclosure;
[0053] Figure 6 is a schematic diagram of another first electrode provided in an embodiment of this disclosure;
[0054] Figure 7 is a schematic diagram of another first electrode provided in an embodiment of this disclosure;
[0055] Figure 8 is a schematic diagram of another display substrate provided in an embodiment of this disclosure;
[0056] Figures 9 and 10 are schematic diagrams of another display substrate provided in an embodiment of this disclosure;
[0057] Figures 11 and 12 are schematic diagrams of a mask provided in an embodiment of this disclosure;
[0058] Figures 13 and 14 are schematic diagrams of another mask provided in an embodiment of this disclosure;
[0059] Figures 15 and 16 are schematic diagrams of another mask provided in an embodiment of this disclosure;
[0060] Figures 17 and 18 are schematic diagrams of another mask provided in an embodiment of this disclosure;
[0061] Figures 19 and 20 are schematic diagrams of another mask provided in an embodiment of this disclosure;
[0062] Figures 21 and 22 are schematic diagrams of another mask provided in an embodiment of this disclosure;
[0063] Figure 23 is a schematic diagram of the fabrication of a display substrate provided in an embodiment of this disclosure.
[0064] Figure Descriptions: Substrate 1', Conductive Layer 02', Photoresist 3', Anode 2', Mask 4'; Substrate 1, Light-Emitting Structure 2, First Electrode 21, Light-Emitting Layer 22, First Surface 21a, Concave Surface 21a1, Second Surface 21b, First Direction X, Sub-Surface 21a2, Transition Surface 21a3, Bottom Surface 21a11, Side Surface 21a12, Pixel Definition Layer 3, Driving Circuit 4, Power Supply 5, Power Line 6, Second Electrode 7, Encapsulation Layer 8; Exposure Structure A, Exposure Adjustment Structure A1, Incident Surface a, Exit Surface b, Fully Light-Shielding Structure A2, Fully Light-Transmitting Structure B; Conductive Layer 021, Photoresist 9. Detailed Implementation
[0065] This disclosure provides a display substrate and its manufacturing method, a photomask, and a display device to solve the problems of low luminous efficiency and low luminous uniformity in existing OLED display products.
[0066] It should be understood that the specific structural and functional details disclosed in the embodiments of this disclosure are merely representative and are intended to describe exemplary embodiments of this disclosure. However, this disclosure can be implemented in many alternative or combined forms and should not be construed as being limited solely to the embodiments set forth herein.
[0067] In the description of this disclosure, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof are intended to cover non-exclusive inclusion.
[0068] To make the above-described objects, features, and advantages of this disclosure more apparent and understandable, the disclosure will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the disclosure more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction as described in this disclosure are illustrative of the accompanying drawings, but changes may be made as needed, and all such changes are included within the scope of protection of this disclosure. The accompanying drawings of this disclosure are for illustrative purposes only and do not represent actual scale.
[0069] It should be noted that specific details are set forth in the following description to provide a full understanding of this disclosure. However, this disclosure can be implemented in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this disclosure. Therefore, this disclosure is not limited to the specific embodiments disclosed below. The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of illustrating the general principles of this disclosure and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure shall be determined by the appended claims.
[0070] In OLED display panels, the anode functions as a hole injection layer. The anode is responsible for injecting positive charges (holes) into the device, thereby promoting the recombination of electrons and holes during electroluminescence, which in turn generates photons.
[0071] Please refer to Figure 1, which is a schematic diagram of the formation of an anode in the related art.
[0072] S11. A conductive layer 02' is deposited on one side of the substrate 1', a photoresist 3' is coated on the side of the conductive layer 02' away from the substrate 1', and the pattern of the mask 4' is transferred to the photoresist 3'.
[0073] S12. Pattern the conductive layer 02' so that the pattern of the photoresist 3' is transferred to the conductive layer 02', resulting in multiple anodes 2'.
[0074] The inventors discovered that the flatness of the side of the anode 2' away from the substrate 1 obtained by Figure 1 is one of the reasons for the low luminous efficiency of the OLED light-emitting device; and the varying lengths of the power supply lines corresponding to different OLEDs in the OLED display panel cause inconsistent voltage drops for different OLEDs, resulting in poor luminous uniformity of the OLED display panel.
[0075] To address the aforementioned issues, this disclosure provides a display substrate, a method for manufacturing the same, a photomask, and a display device, which will be described in detail below with reference to the accompanying drawings.
[0076] Please refer to Figure 2, which is a schematic diagram of the structure of a display substrate provided in an embodiment of this disclosure. The display substrate includes:
[0077] Substrate 1;
[0078] Multiple light-emitting structures 2 are arranged in an array. Each light-emitting structure 2 includes a first electrode 21 and a light-emitting layer 22. The first electrode 21 is located between the substrate 1 and the light-emitting layer 22. The first surface 21a of the first electrode 21 away from the substrate 1 includes a concave surface 21a1, which is located in the pixel area (not shown) corresponding to the light-emitting structure 2. The second surface 21b of the first electrode 21 close to the substrate 1 is a plane.
[0079] The depth of the concave surface 21a1 of the first electrodes 21 arranged along the first direction X gradually increases; wherein, the first direction X is the direction from one side of the array to the opposite side of the array, and the power supply (not shown in Figure 2) for powering the first electrodes 21 is located on the other side, or the first direction X is the direction from the center of the array to the power supply (not shown in Figure 2), and the power supply is located on one side and the other side of the array. If the power supply is located on one side of the array (i.e., the light-emitting structure 2 uses single-sided power supply), the first direction X is the direction from one side of the array to the opposite side; if the power supply is located on both sides of the array (i.e., the light-emitting structure 2 uses double-sided power supply), the first direction X is the direction from the center of the array to the power supply.
[0080] The first electrode 21 can be made of a conductive material, such as indium tin oxide (ITO) or a metallic material. When the first electrode 21 is made of a metallic material, it can also reflect the light emitted by the light-emitting layer 22 to improve the optical properties of the light-emitting structure 2, increase the effective angle of the emitted light, optimize the refraction and reflection of light, thereby improving the brightness and viewing angle characteristics of the light-emitting structure 21.
[0081] As shown in Figure 2, the depths of the concave surfaces 21a1 of the three first electrodes 21 arranged along the first direction X are h1, h2, and h3, respectively, where h1>h2>h3. As can be seen from Figure 2, since the second surface 21b of the first resistor 21 is a plane, the depth of the concave surface 21a1 of the first electrodes 21 arranged along the first direction X can be gradually increased, thereby gradually reducing the cross-sectional area of the first electrodes 21 arranged along the first direction X. This results in a gradual increase in the resistance of the first electrodes 21 arranged along the first direction X, which in turn makes the voltage drop from the power supply to each first electrode 21 more uniform, thereby improving the light emission uniformity of the display substrate.
[0082] If the first electrode 21 is made of a metal material, as shown in FIG3, which is a schematic diagram of another display substrate structure provided in the present disclosure, when the depth of the concave surface 21a1 of each first resistor 21 is the same, the resistance of the first electrodes 21 with the same depth of concave surface 21a1 arranged along the first direction X can be gradually increased by changing the film structure of the first electrode 21, so that the voltage drop from the power supply to each first electrode 21 tends to be consistent.
[0083] Of course, by simultaneously changing the depth of the concave surface 21a1 of the first electrode 21 and the film structure of the first electrode 21, the resistance of the first electrodes 21 with the same depth of concave surface 21a1 arranged along the first direction X can be gradually increased. This can reduce the concave depth of the first electrode 21 with the largest resistance, thereby improving the flatness of the display substrate.
[0084] By configuring the first surface 21a of the first electrode 21 away from the substrate 1 to include a concave surface 21a1, the effective contact area between the light-emitting layer 22 and the first electrode 21 can be increased, thereby increasing the contact area between electrons and holes in the light-emitting structure 2 and increasing the probability and efficiency of recombination. Since this structure fully considers the physical processes of carrier transport and recombination within the light-emitting structure 2, it can comprehensively improve the performance of the light-emitting structure 2. Furthermore, since a larger contact area helps to improve the efficiency of electron injection, it can reduce voltage loss during current injection and improve the energy efficiency ratio of the light-emitting structure 2. The depth of the concave surface 21a1 of the first electrodes 21 arranged along the first direction X is set to gradually increase. Here, the first direction X is the direction from one side of the array to the opposite side, and the power supply (not shown in Figure 2) for the first electrodes 21 is located on the other side; or the first direction X is the direction from the center of the array to the power supply (not shown in Figure 2), and the power supply is located on both sides of the array. Under the control of the same driving data, the voltage drop from the power supply to each first electrode 21 in the display substrate can be made more uniform, thereby improving the light emission uniformity of the display substrate. Compared with related technologies that use redundant traces to improve light emission uniformity, this method effectively reduces the number of redundant traces, thus reducing the area occupied by redundant traces and achieving a narrow bezel design. Furthermore, since only one concave surface 21a1 is designed on the first surface 21a of the first electrode 21, the flatness of the film layer formed on the first surface 21a side is higher than that with multiple concave surfaces 21a1.
[0085] As shown in Figure 2, the first surface 21a of the first electrode 21 can be entirely concave 21a1. However, during the fabrication of the concave surface 21a1, the edges of the concave surface 21a1 are prone to over-etching, which will reduce the depth of the concave surface 21a1 and make the structure of the edge of the concave surface 21a1 unstable, which is not conducive to the fabrication of subsequent processes.
[0086] Please refer to Figure 4, which is a schematic diagram of the structure of a first electrode according to an embodiment of this disclosure. The first surface 21a of the first electrode 21 includes:
[0087] Concave surface 21a1 and sub-surface 21a2 connected to the edge of concave surface 21a1;
[0088] Sub-face 21a2 surrounds concave face 21a1 and is parallel to second face 21b.
[0089] As shown in Figure 4, the first surface 21a may include not only the concave surface 21a1, but also a sub-surface 21a2 that surrounds the edge of the concave surface 21a1 and connects to the edge of the concave surface 21a1. The sub-surface 21a2 is parallel to the second surface 21b. Since the second surface 21b is a plane, the sub-surface 21a2 is also a plane. This can increase the width of the edge of the concave surface 21a1, keep the edge position of the concave surface 21a1 structurally stable, and when etching the concave surface 21a1, even if there is over-etching at the edge of the concave surface 21a1, the depth of the concave surface 21a1 will not be reduced, so that the structure of the first electrode 21 can meet the design specifications.
[0090] Please refer to Figure 5, which is a schematic diagram of another first electrode structure provided in an embodiment of this disclosure. The first surface 21a further includes:
[0091] The transition surface 21a3 connects the concave surface 21a1 and the sub-surface 21a2, so that the concave surface 21a1 and the sub-surface 21a2 transition smoothly.
[0092] By providing a transition surface 21a3 between the concave surface 21a1 and the sub-surface 21a2 to smoothly transition between the concave surface 21a1 and the sub-surface 21a2, it is possible to avoid the appearance of a sharp point in the first surface 21a due to the concave surface 21a1 being provided in the first surface 21a, thereby preventing the current density from concentrating at the sharp point and improving the uniformity of the current density of the first electrode 21 and reducing the heat generation of the first electrode 21.
[0093] Please refer to Figure 4. The longitudinal section of the concave surface 21a1 is an elliptical arc. As shown in Figure 6, which is a schematic diagram of another first electrode provided in this embodiment, the longitudinal section of the concave surface 21a1 can also be a circular arc.
[0094] By setting the longitudinal section pattern of the concave surface 21a1 as an elliptical arc or a circular arc, the curvature of the concave surface 21a1 can be continuously changed, allowing the current density on the concave surface 21a1 to be evenly distributed, thereby improving the light emission uniformity of the light-emitting structure 2.
[0095] Please refer to Figure 7, which is a schematic diagram of another first electrode structure provided in an embodiment of this disclosure. The concave surface 21a1 in the first surface 21a includes:
[0096] The bottom surface 21a11 and the side surface 21a12 surrounding the bottom surface 21a11, the bottom surface 21a11 is a plane and the side surface 21a12 is an arc surface 21a12, and the bottom surface 21a11 and the side surface 21a12 are smoothly transitioned.
[0097] By setting the bottom surface 21a11 of the concave surface 21a11 as a plane and the side surface 21a12 connected to the bottom surface 21a11 as an arc surface 21a12, and making the side surface of the bottom surface 21a11 transition smoothly, not only can the curvature of the concave surface 21a1 change continuously, but also the surface area of the concave surface 21a1 can be increased while reducing the depth of the concave surface 21a1, thereby improving the luminous efficiency and luminous uniformity of the light-emitting structure 2, and improving the flatness of other film layers formed on the concave surface 21a1.
[0098] Please refer to Figure 8, which is a schematic diagram of another display substrate provided in an embodiment of this disclosure. The display substrate further includes:
[0099] Pixel definition layer 3 is disposed in the gap between adjacent first electrodes 21;
[0100] The second electrode 7 is located on the side of the light-emitting layer 22 away from the substrate 1;
[0101] The encapsulation layer 8 is located on the side of the light-emitting layer 22 away from the substrate 1.
[0102] Since most of the thickness of the light-emitting layer 22 is located within the concave surface 21a1 of the first electrode 21, the pixel definition layer 3 can be placed in the gap between adjacent first electrodes 21, so that the pixel definition layer 3 is higher than the height of the first electrode 21. This can minimize the thickness of the display substrate and facilitate a thinner and lighter design.
[0103] In some embodiments, the roughness of the concave surface 21a1 is greater than or equal to 1 nm and less than or equal to 10 nm.
[0104] By using photolithography to form the concave surface 21a1 of the first electrode 21, the roughness of the first electrode 21 can be greater than or equal to 1 nm and less than or equal to 10 nm. This improves the smoothness of the concave surface 21a1, thereby enabling the current to be uniformly distributed on the concave surface 21a1. Therefore, in this disclosure, by setting the roughness of the concave surface 21a1 to be greater than or equal to 1 nm and less than or equal to 10 nm, the concave surface 21a1 of the first electrode 21 can be formed using photolithography. Compared with other etching processes, this results in a smoother surface and higher curvature continuity of the concave surface 21a1.
[0105] In some embodiments, the curvature of the concave surface 21a1 changes continuously, so that the current density of the concave surface 21a1 can be uniformly distributed.
[0106] Please refer to Figures 9 and 10 for schematic diagrams of another display substrate provided in an embodiment of this disclosure. The display substrate further includes:
[0107] The driving circuit 4 is connected to the first electrode 21;
[0108] Power supply 5;
[0109] Power line 6 is connected between power supply 5 and drive circuit 4; when drive circuit 4 drives light-emitting structure 2 to emit light, power supply 5 supplies power to first electrode 21 through drive circuit 4 and power line 6.
[0110] The total resistance of each first electrode 21 and its corresponding power line 6 is within the error range of the preset resistance value.
[0111] Power supply 5 is usually provided by the scanning circuit (not shown), and can be either a positive or negative power supply, depending on the type of driving transistor used in the driving circuit 4, which is not limited here.
[0112] As shown in Figure 9, if the display substrate uses single-sided driving, that is, the scanning circuit (not shown) is located on one side of the array of multiple first electrodes 21, the location of the power supply 5 supplying the first electrodes 21 is the location of the scanning circuit. Therefore, the resistance of the first electrode 21 closest to the power supply 5 is the largest, and the resistance of the first electrode 21 farthest from the power supply 5 is the smallest. The resistance of the first electrodes 21 arranged along the first direction X gradually increases. Since the length of the power line 6 corresponding to the first electrodes 21 arranged along the first direction X gradually decreases, the resistance of the corresponding power line 6 gradually decreases. This makes the total resistance of each first electrode 21 arranged along the first direction X and the corresponding power line 6 within the error range of the preset resistance value (i.e., each total resistance is approximately the same). In this way, under the same brightness data, the voltage drop of each light-emitting structure 2 in the display substrate can be made approximately the same, thereby improving the uniformity of the brightness of the display substrate.
[0113] As shown in Figure 10, if the display substrate uses a dual-sided drive, power supplies 5 are provided on both sides of the array of first electrodes 21. Therefore, the resistance of the first electrode 21 closest to the center line OO' of the display substrate is the smallest, while the resistance of the first electrodes 21 on both sides is the largest, and the resistance of the first electrodes 21 arranged along the first direction X gradually increases. Since the length of the power supply line 6 corresponding to the first electrodes 21 arranged along the first direction X gradually decreases, the resistance of the corresponding voltage line gradually decreases. This ensures that the total resistance of each first electrode 21 arranged along the first direction X and the corresponding power supply line 6 is within the error range of the preset resistance value. Thus, under the same brightness data, the voltage drop of each light-emitting structure 2 in the display substrate can be made approximately the same, thereby improving the uniformity of the brightness of the display substrate.
[0114] It should be noted that the total resistance is within the error range of the preset resistance value and can be regarded as the total resistance being approximately the same; the power supply 5 in Figures 9 and 10 is only to illustrate its relative positional relationship with the multiple first electrodes 21.
[0115] Based on the same inventive concept, this disclosure provides a photomask. Please refer to Figures 11 and 12 for schematic diagrams of the structure of a photomask provided in this disclosure. The photomask includes:
[0116] Multiple exposure structures A are arranged in an array. Each exposure structure A includes at least an exposure adjustment structure A1. In the direction Y from the center region of the exposure adjustment structure A1 to the edge of the exposure adjustment structure A1, the light transmittance through the exposure adjustment structure A1 gradually decreases or increases. The exposure adjustment structure A1 is used to form the concave surface of the first electrode in the display substrate as described above.
[0117] As shown in Figure 11, the longitudinal cross-sectional pattern of the exposure adjustment structure A1 can be a convex shape, allowing it to act as a convex lens. Consequently, in the direction Y from the center of the exposure adjustment structure A1 towards its edge, the light transmittance gradually decreases or increases, creating a concave surface within the photoresist area covered by the exposure adjustment structure A1. This allows the photoresist pattern to be transferred to the first electrode, forming a concave first electrode. Setting the longitudinal cross-sectional pattern of the exposure adjustment structure A1 in the mask to a convex shape makes the concave surface of the fabricated first electrode smoother and its curvature change more continuous. Alternatively, the longitudinal cross-sectional pattern of the exposure adjustment structure A1 can be a rectangle as shown in Figure 12. In the direction Y from the center of the exposure adjustment structure A1 towards its edge, the light transmittance gradually decreases. By controlling the light transmittance of different areas of the exposure adjustment structure A1, a concave surface is formed within the photoresist area covered by the exposure adjustment structure A1, thus transferring the photoresist pattern to the first electrode and forming a concave first electrode. Furthermore, this design for controlling exposure provides greater flexibility for the design of exposure adjustment structures A1 with different light transmittance, allowing for rapid adjustments to meet different design requirements and thus shortening the design cycle.
[0118] Please refer to Figures 13 and 14 for another structural schematic diagram of a photomask provided in an embodiment of this disclosure. The light passes through the central region of the exposure adjustment structure A1 in a uniform manner, so that the photoresist covering the central region can be etched into a plane.
[0119] In the direction Y from the center of the exposure adjustment structure A1 to its edge, the light transmittance through the exposure adjustment structure A1 gradually decreases, indicating the use of positive photoresist; in the direction Y from the center of the exposure adjustment structure A1 to its edge, the light transmittance through the exposure adjustment structure A1 gradually increases, indicating the use of negative photoresist. This is necessary to form a photoresist with a concave surface.
[0120] It should be noted that the center line of the exposure adjustment structure A1 in Figures 11 and 12 (i.e., the dotted line shown in the figure) is considered as the central area of the exposure adjustment structure A1.
[0121] In the embodiments provided by the present invention, by adjusting the exposure adjustment structure A1 in the photomask in the direction Y from the center region of the exposure adjustment structure A1 to the edge of the exposure adjustment structure A1, the transmittance of light through the exposure adjustment structure A1 is gradually reduced or increased. This allows for precise control of the shape of the concave surface of the first electrode, and also avoids optical interference and blurring that may occur in traditional methods, ensuring the consistency of each exposure and thus improving the uniformity of the final product. Furthermore, this photomask design can realize complex concave structures in a single photolithography step, reducing process steps and improving production efficiency.
[0122] Please refer to Figures 15 and 16 for another structural schematic diagram of a photomask provided in an embodiment of this disclosure. The exposure adjustment structure A1 includes:
[0123] Incident surface a and exit surface b; light enters the exposure adjustment structure A1 from incident surface a, and light exits from exit surface b;
[0124] At least one of the incident surface a and the exit surface b has an arc surface, and the end of the arc surface near the central region is closest to the light source (not shown), so that the light incident on the exposure adjustment structure A1 is mainly focused on the photoresist (not shown) covering the central region.
[0125] As shown in Figure 11, both the exit surface b and the incident surface a have curved surfaces, and the exit surface b is parallel to the incident surface a.
[0126] As shown in Figure 15, the incident surface a is a plane, and the exit surface b has an arc surface;
[0127] As shown in Figure 16, the incident surface a has an arc surface, and the exit surface b is a plane.
[0128] The photomasks in Figures 11-15 use positive photoresist, while the photoresist used in the photomask in Figure 16 is negative photoresist.
[0129] In the embodiments provided by the present invention, by making at least one of the incident surface a and the exit surface b of the exposure adjustment structure A1 have an arc surface, and the end of the arc surface near the central region is closest to the light source corresponding to the light, the exposure adjustment structure A1 can be made into a convex structure. In this way, a specific concave surface can be formed directly in the photoresist. Using this scheme, the curvature and depth of the concave surface of the first anode can be designed more accurately.
[0130] Please refer to Figures 17 and 18 for a schematic diagram of another mask provided in an embodiment of this disclosure.
[0131] As shown in Figure 17, when the photoresist used on the mask is a positive photoresist and the longitudinal cross-sectional pattern of the exposure adjustment structure A1 is a raised pattern, the height of the raised exposure adjustment structures A1 arranged in the first direction X gradually decreases, thus changing the resistance of the corresponding first electrode. In Figure 17, the heights of the three exposure adjustment structures A1 arranged in the first direction are h'1, h'2, and h'3, respectively, with h'1... <h'2<h'3。
[0132] The photoresist used on the mask is a positive photoresist, and the longitudinal cross-sectional pattern of the exposure adjustment structure A1 is rectangular. The light transmittance of the exposure adjustment structure A1 arranged in the first direction X gradually decreases, which can change the resistance of the corresponding first electrode.
[0133] As shown in Figure 18, when the photoresist used on the mask is a negative photoresist and the longitudinal cross-sectional pattern of the exposure adjustment structure A1 is a raised pattern, the height of the raised exposure adjustment structures A1 arranged in the first direction X gradually increases, which can change the resistance of the corresponding first electrode. In Figure 18, the heights of the three exposure adjustment structures A1 arranged in the first direction are h'3, h'2, and h'1, respectively. <h'2<h'3。
[0134] The photoresist used on the mask is a negative photoresist, and the longitudinal cross-sectional pattern of the exposure adjustment structure A1 is rectangular. The light transmittance of the exposure adjustment structure A1 arranged in the first direction X gradually increases, which can change the resistance of the corresponding first electrode.
[0135] It should be noted that Figures 17 and 18 only show one exposure adjustment structure A1 corresponding to positive photoresist and negative photoresist, respectively. In this disclosure, the exposure adjustment structure A1 that can be used for positive photoresist and the pattern with a raised longitudinal section can have its protrusion height set in the manner shown in Figure 17; in this disclosure, the exposure adjustment structure A1 that can be used for negative photoresist and the pattern with a raised longitudinal section can have its protrusion height set in the manner shown in Figure 18.
[0136] Please refer to Figures 19 and 20 for another structural schematic diagram of a mask provided in an embodiment of this disclosure.
[0137] Exposure structure A also includes a light-blocking structure A2, which surrounds exposure adjustment structure A1; wherein, when the longitudinal cross-sectional shape of exposure adjustment structure A1 is rectangular, the light transmittance of exposure adjustment structure A1 gradually decreases in the direction from the central region of exposure adjustment structure A1 to the edge of exposure adjustment structure A1.
[0138] The photomask also includes a fully transparent structure B (shown by the dashed line), which surrounds the exposure structure A. The full exposure structure A can be configured as an opening, allowing light to pass completely through the fully transparent structure B.
[0139] The photoresist used in the masks corresponding to Figures 19 and 20 is a positive photoresist. By setting a full-light-shielding structure A2 around the exposure adjustment structure A1 in the exposure structure A, the structural stability of the concave edge of the photoresist can be increased.
[0140] Please refer to Figures 21 and 22 for a schematic diagram of another mask provided in an embodiment of this disclosure.
[0141] The first exposure structure A also includes a full exposure structure A, which surrounds the exposure adjustment structure A1; wherein, when the longitudinal cross-sectional shape of the exposure adjustment structure A1 is rectangular, the light transmittance of the exposure adjustment structure A1 gradually increases in the direction from the central region of the exposure adjustment structure A1 to the edge of the exposure adjustment structure A1.
[0142] The photomask also includes a fully light-blocking structure A2, which surrounds the exposure structure A.
[0143] The photoresist used in the masks corresponding to Figures 21 and 22 is a negative photoresist. By setting a full exposure structure A surrounding the exposure adjustment structure A1 in the exposure structure A, the structural stability of the concave edge of the photoresist can be increased.
[0144] Based on the same inventive concept, this disclosure provides a method for manufacturing a display substrate. Please refer to Figure 23, which is a schematic diagram of the manufacturing process of a display substrate according to an embodiment of this disclosure, including:
[0145] S21: Deposit a conductive layer 021 on one side of the substrate 1;
[0146] S22: A photoresist layer is formed on the side of the conductive layer 021 away from the substrate 1;
[0147] S23: A mask as described above is provided on the side of the photoresist 9 away from the substrate 1, and the photoresist is patterned using the mask so that the side of the photoresist away from the substrate 1 has multiple concave surfaces 21a1 arranged in an array.
[0148] S24: The pattern of photoresist 9, including multiple concave surfaces 21a1, is transferred to conductive layer 021 to obtain multiple first electrodes 21; the first surface 21a of the first electrode 21 away from the substrate 1 includes a concave surface 21a1, and the second surface 21b of the first electrode 21 near the substrate 1 is a plane; the depth of the concave surface 21a1 of the first electrodes 21 arranged along the first direction X gradually increases; wherein, the first direction X is the direction from one side of the array to the opposite side of the array, and the power supply (not shown) for the first electrode 21 is located on the other side, or the first direction X is the direction from the center of the array to the power supply (not shown), and the power supply is located on one side and the other side of the array.
[0149] When transferring the pattern of photoresist 9 to conductive layer 021, the etching rate can be controlled between tens of nanometers and hundreds of nanometers per minute. This allows for faster removal of thinner photoresist and slower removal of thicker photoresist, ensuring that the pattern of the first electrode 21 is consistent with that of the photoresist 9. The etching time can be between 3 and 10 minutes, which ensures the removal of thicker photoresist while avoiding over-etching of the first electrode, thus accurately transferring the pattern of photoresist 9 onto the first electrode.
[0150] S25: On the side of the plurality of first electrodes 21 away from the substrate 1, a light-emitting layer 22 corresponding to each first electrode 21 is formed; wherein, the light-emitting structure 2 includes the first electrode 21 and the corresponding light-emitting layer 22.
[0151] Figure 23 shows an example of fabricating the first electrode 21 using the mask shown in Figure 11, with positive photoresist used. The fabrication process is similar when using other masks for the first electrode 21, and will not be described in detail here.
[0152] Based on the same inventive concept, this disclosure provides a display device, which includes the display substrate described above.
[0153] The display substrate can be a display panel; the display substrate can also be a light-emitting structure array arranged opposite to the silicon-based backplane. The arrangement of the power lines in the silicon-based backplane that provide power to the first electrode in the display substrate can be referred to the arrangement of the power lines in the aforementioned display substrate, and will not be repeated here.
[0154] The display device can be a monitor, display screen, television, or other display device; it can also be a mobile device such as a mobile phone, tablet computer, laptop, personal digital assistant (PDA), in-vehicle computer, or wearable device. The display device includes a frame, a display panel housed within the frame, a circuit board, a display driver IC, and other electronic components.
[0155] The display substrate can be an organic light-emitting diode (OLED) display panel, a quantum dot light-emitting diode (QLED) display panel, a micro light-emitting diode (Micro LED) display panel, etc., and this disclosure does not specifically limit it.
[0156] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.
[0157] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.
Claims
1. A display substrate, wherein, include: Substrate; Multiple light-emitting structures are arranged in an array. Each light-emitting structure includes a first electrode and a light-emitting layer. The first electrode is located between the substrate and the light-emitting layer. The first surface of the first electrode away from the substrate includes a concave surface, which is located within the pixel area corresponding to the light-emitting structure. The second surface of the first electrode close to the substrate is a plane. The concave depth of the first electrodes arranged along the first direction gradually increases; wherein, the first direction is the direction from one side of the array to the opposite side of the array, and the power supply for the first electrode is located on the opposite side, or the first direction is the direction from the center of the array to the power supply, and the power supply is located on one side and the opposite side of the array.
2. The display substrate as claimed in claim 1, wherein, The first side includes: The concave surface and the sub-surface connected to the edge of the concave surface; The sub-face surrounds the concave surface and is parallel to the second face.
3. The display substrate as described in claim 2, wherein, The first side also includes: A transition surface connects the concave surface and the sub-surface, allowing for a smooth transition between the concave surface and the sub-surface.
4. The display substrate according to any one of claims 1-3, wherein, The concave surface includes: The bottom surface and the side surface surrounding the bottom surface, wherein the bottom surface is a plane and the side surface is an arc surface, and the bottom surface and the side surface are smoothly transitioned.
5. The display substrate according to any one of claims 1-3, wherein, The longitudinal section of the concave surface includes: Circular arc or elliptical arc.
6. The display substrate according to any one of claims 1-5, wherein, The resistance of the first resistors arranged along the first direction gradually increases.
7. The display substrate according to any one of claims 1-6, wherein, The roughness of the concave surface is greater than or equal to 1 nm and less than or equal to 10 nm.
8. The display substrate according to any one of claims 1-7, wherein, The display substrate further includes: The driving circuit is connected to the first electrode; The power source; A power supply line is connected between the voltage and the driving circuit; when the driving circuit drives the light-emitting structure to emit light, the power supply provides power to the first electrode through the driving circuit and the power supply line. The total resistance of each first electrode and its corresponding power line is within the error range of the preset resistance value.
9. A photomask, wherein, include: Multiple exposure structures arranged in an array, each exposure structure including at least an exposure adjustment structure, wherein the light transmittance through the exposure adjustment structure gradually decreases or increases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure; the exposure adjustment structure is used to form a concave surface of a first electrode in a display substrate as described in any one of claims 1-8.
10. The photomask as claimed in claim 9, wherein, The exposure adjustment structure includes: An incident surface and an exit surface; light rays enter the exposure adjustment structure from the incident surface and exit from the exit surface; At least one of the incident surface and the exit surface has an arc surface, and the end of the arc surface closest to the central region is closest to the light source corresponding to the light, so that the light incident on the exposure adjustment structure is mainly focused on the photoresist covering the central region.
11. The photomask as claimed in claim 10, wherein, Both the exit surface and the incident surface have arc surfaces, and the exit surface is parallel to the incident surface; Alternatively, the incident surface is a plane and the exit surface has an arc surface.
12. The photomask as claimed in claim 10, wherein, The incident surface has an arc surface, and the exit surface is a plane.
13. The photomask as claimed in claim 9, wherein, The longitudinal cross-sectional shape of the exposure adjustment structure is rectangular; In the direction from the center region of the exposure adjustment structure to the edge of the exposure adjustment structure, the light transmittance of the exposure adjustment structure gradually decreases or increases.
14. The photomask as claimed in claim 11 or 13, wherein, The exposure structure further includes a light-blocking structure that surrounds the exposure adjustment structure; wherein, when the longitudinal cross-sectional shape of the exposure adjustment structure is rectangular, the light transmittance of the exposure adjustment structure gradually decreases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure. The photomask also includes a fully transparent structure surrounding the exposure structure.
15. The photomask as claimed in claim 12 or 13, wherein, The first exposure structure further includes a full exposure structure that surrounds the exposure adjustment structure; wherein, when the longitudinal cross-sectional shape of the exposure adjustment structure is rectangular, the light transmittance of the exposure adjustment structure gradually increases in the direction from the central region of the exposure adjustment structure to the edge of the exposure adjustment structure. The photomask also includes a light-blocking structure, which surrounds the exposure structure.
16. A method for manufacturing a display substrate, wherein, include: A conductive layer is deposited on one side of the substrate. A photoresist layer is formed on the side of the conductive layer away from the substrate. A photomask as described in any one of claims 9-15 is disposed on the side of the photoresist away from the substrate, and the photoresist is patterned using the photomask so that the side of the photoresist away from the substrate has a plurality of concave surfaces arranged in an array. A pattern of photoresist including the plurality of concave surfaces is transferred to the conductive layer to obtain a plurality of first electrodes; the first surface of the first electrode away from the substrate includes a concave surface, and the second surface of the first electrode close to the substrate is a plane; the depth of the concave surfaces of the first electrodes arranged along a first direction gradually increases; wherein, the first direction is the direction from one side of the array to the opposite side, and the power supply for the first electrode is located on the opposite side, or the first direction is the direction from the center of the array to the power supply, and the power supply is located on one side and the opposite side of the array; On the side of the plurality of first electrodes away from the substrate, a light-emitting layer corresponding to each first electrode is formed; wherein, the light-emitting structure includes the first electrode and the corresponding light-emitting layer.
17. A display device, wherein, Includes the display substrate as described in any one of claims 1-8.