Touch structure, display panel and preparation method thereof

Abstract

The present disclosure provides a touch structure, a display panel and a preparation method thereof. The touch structure comprises a metal grid layer, the metal grid layer comprises a metal trace, the metal trace has a length direction and a width direction, the metal trace has opposite first and second side edges in the width direction, the first and second side edges extend in a non-linear shape in the length direction; and / or the metal trace comprises a plurality of sequentially connected trace segments in the length direction, at least two different thicknesses exist in the plurality of trace segments.

Description

Technical Field

[0001] This disclosure relates to the field of touch technology. More specifically, it relates to a touch structure, a display panel, and a method for manufacturing the same. Background Technology

[0002] OLED display panels have become one of the mainstream technologies in the display panel market due to their advantages such as high contrast and wide viewing angle. They often use metal mesh to realize touch functions. However, in practical applications, the metal traces on the metal mesh layer are easily visible to the naked eye in dark conditions, presenting visual defects such as bright and dark stripes. Moreover, the color deviation is serious at wide viewing angles, which seriously affects the display quality of the panel and the user experience. Summary of the Invention

[0003] The purpose of this disclosure is to provide a touch structure, a display panel, and a method for manufacturing the same, in order to solve at least one of the aforementioned technical problems.

[0004] To achieve the above objectives, the present disclosure adopts the following technical solution: A first aspect of this disclosure provides a touch structure including a metal mesh layer, the metal mesh layer including metal traces having a length direction and a width direction, the metal traces having opposing first and second side edges in the width direction, the first and second side edges extending non-linearly in the length direction; and / or The metal trace includes multiple trace segments connected in sequence along its length, and at least two different thicknesses exist among the multiple trace segments.

[0005] Optionally, the non-linear shape is at least one of sawtooth, wavy, arc, or polygonal.

[0006] Optionally, the non-linear shape is an arc shape, and the first side edge and the second side edge include a plurality of arc shapes connected in sequence in the length direction, wherein there are at least two different radii of curvature among the plurality of arc shapes.

[0007] Optionally, the metal mesh layer includes a plurality of basic mesh units arranged repeatedly along the planar direction. The basic mesh unit includes a first mesh unit and a second mesh unit arranged adjacent to each other. The arc shape of the metal trace forming the first mesh unit has a first radius of curvature, and the arc shape of the metal trace forming the second mesh unit has a second radius of curvature. The first radius of curvature and the second radius of curvature are different.

[0008] Optionally, the ratio of the radius of curvature of the arc to the width of the metal trace is in the range of 0.5 to 2.

[0009] Optionally, the radius of curvature ranges from 2 to 20 μm, and the width of the metal trace ranges from 4 to 6 μm.

[0010] Optionally, the thickness of the metal trace is periodically distributed along the length direction, and each thickness variation period includes multiple trace segments connected sequentially along the length direction. The thickness of each trace segment is distributed in a stepped manner within any thickness variation period.

[0011] Optionally, within each thickness variation cycle, the difference between the maximum and minimum thickness of the trace segment is an integer multiple of half a predetermined wavelength.

[0012] Optionally, the thickness of each trace segment ranges from 0.4 to 1 μm, and the predetermined wavelength is 550 nm.

[0013] Optionally, the metal mesh layer includes a first metal layer, an insulating layer, and a second metal layer stacked sequentially. Both the first metal layer and the second metal layer are provided with multiple metal traces. In the top view of the metal mesh layer, the metal traces in the first metal layer and the metal traces in the second metal layer are arranged in an alternating pattern to form a mesh pattern with multiple hollow areas.

[0014] A second aspect of this disclosure provides a display panel, including a display substrate and a touch structure as described above. The touch structure is disposed on the light-emitting side of the display substrate. The display substrate includes a plurality of pixel regions distributed in an array. Any hollow area of ​​the metal mesh layer in the touch structure corresponds to at least one pixel region on the display substrate.

[0015] This disclosure provides a third aspect of a method for manufacturing a display panel, comprising the following steps: A display substrate is provided, the display substrate comprising a plurality of pixel regions arranged in an array; A metal mesh layer is fabricated on the light-emitting side of the display substrate. Any cutout area of ​​the metal mesh layer corresponds to at least one pixel region on the display substrate. The metal mesh layer includes metal traces, which have a length direction and a width direction. The metal traces have opposing first and second side edges in the width direction, wherein: The first side edge and the second side edge extend in a non-linear manner along the length direction; and / or The metal trace comprises a plurality of trace segments connected in sequence along its length, and at least two different thicknesses exist among the plurality of trace segments.

[0016] Optionally, at least two different thicknesses exist among the plurality of trace segments, and the step of fabricating a metal mesh layer on the light-emitting side of the display substrate includes: Using a first mask, a first sub-metal trace is formed on the display substrate by a vapor deposition process. The thickness of the first sub-metal trace is the minimum thickness among the plurality of trace segments. The orthographic projection of the first sub-metal trace on the display substrate coincides with the orthographic projection of the metal trace on the display substrate. A portion of the first sub-metal trace is masked using a second mask, and the unmasked area is thickened using a vapor deposition process. The thickening process is performed at least once, so that the areas that have undergone different thickening processes have different thicknesses, thereby forming multiple trace segments distributed along the length direction and having at least two thicknesses.

[0017] The beneficial effects of this disclosure are as follows: The touch structure of this disclosure, by using a non-linear design for the side edges of the metal traces and / or a segmented, differentiated thickness design for the metal traces, can disrupt the path of reflected light and / or break the interference condition of constant phase difference of reflected light at the structural level of the metal traces. This effectively suppresses the interference superposition effect, reduces the visibility of the metal traces, and improves display quality. At the same time, since the above improvements do not change the overall periodic arrangement of the metal mesh, they will not have an adverse effect on the touch function, nor is it necessary to adjust the trace layout to improve visibility. Thus, it can balance the improvement of large field of view color deviation and touch performance. Attached Figure Description

[0018] The specific embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the metal mesh layer in a traditional display module and the visible stripes that appear in the dark state. Figure 2 This is a schematic diagram of the planar distribution of metal traces in a touch structure provided in this disclosure; Figure 3 This is a schematic diagram of the planar distribution of metal traces in another embodiment of the touch structure provided in this disclosure; Figure 4 This is a schematic diagram of the structure of metal traces in a traditional display module; Figure 5 This is a partially enlarged schematic diagram of the metal traces provided in an embodiment of this disclosure; Figure 6 A schematic diagram of an embodiment of a metal mesh layer when two radii of curvature exist in multiple arcs; Figure 7 Figure 3 Cross-sectional view of the metal trace at position A-A'; Figure 8 A schematic diagram of the structure of a metal trace when multiple trace segments have four different thicknesses; Figure 9 This is a schematic diagram of another embodiment of the metal traces in the touch structure provided in this disclosure; Figure 10 This is a schematic diagram of the film structure of one embodiment of the metal mesh layer; Figure 11 This is a schematic diagram of a planar structure of an embodiment of a metal mesh layer; Figure 12 This is a schematic diagram of a planar structure of another embodiment of the metal mesh layer; Figure 13 A flowchart of an embodiment of the method for manufacturing a display panel provided in this disclosure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0021] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0022] The inventors discovered through research that the main reason for the visibility defects such as bright and dark stripes and the problem of color distortion at large viewing angles in display modules that use FMLOC (Flexible Metal Line On Cell) to implement touch functions is that the metal mesh layer in the FMLOC display module usually contains multiple periodically arranged metal traces (such as... Figure 1As shown in Figure (a)), these metal traces are generally distributed periodically in planar space according to the smallest periodic unit. In the dark, when an external point light source is incident on the surface of the display panel, the diffraction fringes generated by a single period are subjected to spatial periodic modulation interference, resulting in visible bright and dark fringes, for example... Figure 1 As shown in Figure (b), the reflection path of the incident light by the metal traces changes with the viewing angle at different angles, resulting in a significant color shift when the display panel is viewed at a wide viewing angle.

[0023] To address the aforementioned technical problems, this disclosure provides a touch structure, a display panel, and a method for manufacturing the same. The embodiments of this disclosure are described in detail below with reference to specific examples.

[0024] Please refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of one embodiment of the touch structure provided in this disclosure. Figure 3 This is a schematic diagram of another embodiment of the touch structure provided in this disclosure, as shown below. Figure 2 and Figure 3 As shown, the touch structure includes a metal mesh layer, the metal mesh layer including metal traces 10, the metal traces 10 having a length direction and a width direction, the metal traces 10 having opposing first side edges L1 and second side edges L2 in the width direction, wherein: the first side edge L1 and the second side edge L2 extend non-linearly in the length direction; and / or The metal trace 10 includes a plurality of trace segments 10a connected in sequence along its length, and at least two different thicknesses exist among the plurality of trace segments 10a.

[0025] Here, the length direction refers to the extension direction of the metal trace 10, and the width direction refers to the direction perpendicular to the length direction. A metal mesh layer typically includes multiple metal traces extending in at least two directions. It should be noted that for metal traces 10 extending in different directions, such as those extending in the horizontal direction X and the vertical direction Y, their respective length directions are their own extension directions. Those skilled in the art can determine the length and width directions based on the specific extension path of the metal trace.

[0026] For example, in Figure 2In the embodiment shown, for a metal trace 10 extending along the horizontal direction X, its width direction is the vertical direction Y. In the width direction of the metal trace 10, the edge located on one side of the metal trace 10 is the first side edge L1, and the edge located on the other side of the metal trace 10 and opposite to the first side edge L1 is the second side edge L2. The first side edge L1 and the second side edge L2 can also be understood as two boundary lines of the metal trace 10 in the width direction. They extend along the length direction of the metal trace 10 and together define the width of the metal trace 10.

[0027] In traditional touch structures, such as Figure 4 As shown in Figure (a), the metal traces 200 of the metal mesh layer are typically straight lines. Assuming the two edge lines of the metal trace 200 in the width direction are represented as L3 and L4 respectively, then L3 and L4 are parallel to each other, and the vertical distance W0 between them is the same at different positions. This vertical distance W0 is the linewidth of the metal trace 200. The metal trace 200 extending along the vertical direction Y will generate diffracted light in the horizontal direction, while the metal trace 200 extending along the horizontal direction X will generate diffracted light in the vertical direction. Therefore, when the two types of metal traces are distributed in the plane to form a square-shaped mesh structure, cross-shaped diffracted light will be generated in the dark, such as... Figure 4 The diagram is shown in Figure (b).

[0028] To improve the aforementioned dark-state visibility problem, in some embodiments: such as Figure 2 As shown, the metal trace 10 can be configured as a non-linear structure. Specifically, the first side edge L1 and the second side edge L2 extend non-linearly along the length direction. When viewed along the length direction of the metal trace, the first side edge L1 and the second side edge L2 are not straight lines parallel to the extension direction of the metal trace 10, but rather undulate relative to the extension direction of the metal trace 10. This configuration effectively disrupts the reflection path of incident light on the surface of the metal trace 10, improving the visibility of the metal trace 10 to the naked eye.

[0029] In some embodiments, such as Figure 3 As shown, the thickness of the metal trace 10 can also be improved to have at least two thicknesses along its length. Here, the thickness can be understood as the height of the metal trace 10 in the direction perpendicular to the first plane, which is either the plane containing the touch structure or a plane parallel to the touch structure. Figure 3 In the example shown, the grayscale of trace segment 10a is used to reflect the thickness of trace segment 10a, with different grayscale values ​​representing different thicknesses.

[0030] Specifically, the elements for interference include: the same frequency, the same vibration direction, and a constant phase difference. In traditional touch structures, all metal traces have the same thickness. When an external point light source is incident on the surface of the metal traces, a fixed and constant phase difference is generated between the reflected light at different positions on the metal traces. Since this phase difference is constant in space, it precisely satisfies the condition of a constant phase difference for interference. Simultaneously, the metal mesh layer in the touch structure is a periodic structure. Along the length of the metal traces, the traces are arranged in a periodic repeating pattern of mesh units. For a single mesh unit, its reflection produces diffraction; when multiple mesh units are periodically repeated, the diffracted light generated by each mesh unit meets in space. Because the interference conditions of the same frequency, the same vibration direction, and a constant phase difference are satisfied, these diffracted lights superimpose and enhance each other, forming a stable interference phenomenon. In other words, the diffraction of a single grid cell is weak and insufficient to form obvious visual defects. However, due to the periodic arrangement, the diffracted light of each grid cell is continuously superimposed and enhanced. After multiple cycles of accumulation, the interference effect is significantly amplified, eventually forming obvious visual phenomena such as bright and dark stripes and shadows, which seriously affect the display quality.

[0031] Based on the above findings, this application embodiment can make the reflected light in different regions have different phases by setting trace segments of different thicknesses in the metal trace 10, breaking the condition of constant phase difference. As a result, constructive interference is no longer formed between the diffracted lights, and even destructive interference is generated under certain conditions, which weakens the intensity of the superimposed reflected light and thus reduces the visibility of the metal trace.

[0032] Compared with related technologies, the touch structure of this disclosure, by designing the side edges of the metal traces with non-linear shapes and / or segmenting the metal traces with differentiated thicknesses, can disrupt the path of reflected light and / or break the interference condition of constant phase difference of reflected light at the structural level of the metal traces. This effectively suppresses the interference superposition effect, reduces the visibility of the metal traces, and improves display quality. At the same time, since the above improvements do not change the overall periodic arrangement of the metal mesh, they will not have an adverse effect on the touch function, nor is it necessary to adjust the trace layout to improve visibility. Thus, it can balance the improvement of large-viewing-angle offset and touch performance.

[0033] Optionally, the non-linear shape is at least one of sawtooth, wavy, arc, or polygonal.

[0034] For example, please refer to Figure 5 , Figure 5 This is a magnified schematic diagram of a portion of the metal trace. Figure 5 Figure (a) shows a schematic diagram in which the first side edge L1 and the second side edge L2 are serrated in the length direction. Figure 5Figure (b) shows a schematic diagram of the first side edge L1 and the second side edge L2 forming a multi-fold line shape along the length direction. Figure 5 The diagram (c) shows that the first side edge L1 and the second side edge L2 are arc-shaped in the length direction. In this case, the first side edge L1 and the second side edge L2 include a plurality of arcs connected in sequence in the length direction, and there is an inflection point between two adjacent arcs.

[0035] It is understood that the above only schematically illustrates a portion of the non-linear structure. In other embodiments, the non-linear shape can have various different shapes and variations. For example, the first side edge and / or the second side edge along the length of the metal trace can be irregularly serrated, wavy with alternating light and dark areas, arc-shaped with non-uniform curvature, or a mixed shape formed by alternating straight and arc segments. As long as the shape variation of the side edge of the metal trace can be distinguished from that of the traditional straight edge, it falls within the protection scope of the non-linear shape of this application.

[0036] Optionally, the non-linear shape is an arc shape, and the first side edge and the second side edge include a plurality of arc shapes connected in sequence in the length direction, wherein there are at least two different radii of curvature among the plurality of arc shapes.

[0037] In this embodiment, the curvature of each arc along the length of the metal trace 10 may not be exactly the same. For example, along the extension direction of the metal trace, each arc may have multiple radii of curvature, and these radii may alternate or change randomly. By setting combinations of arcs with different radii of curvature, the coherence and periodicity of reflected light can be more effectively disrupted, thereby further reducing visibility phenomena and avoiding moiré patterns.

[0038] For example, please refer to Figure 6 ,exist Figure 6 In the illustrated embodiment, there are two types of radii of curvature in the multiple arcs. For the purpose of distinguishing them, they are denoted as the first radius of curvature R1 and the second radius of curvature R2, respectively, where R1 is less than R2.

[0039] In some embodiments, such as Figure 6 As shown, the metal mesh layer includes a plurality of basic mesh units 110 arranged repeatedly along the planar direction. Each basic mesh unit 110 includes a first mesh unit 110a and a second mesh unit 110b arranged adjacent to each other. The arc shape of the metal trace 10 forming the first mesh unit 110a has a first radius of curvature R1, and the arc shape of the metal trace 10 forming the second mesh unit 110b has a second radius of curvature R2. The first radius of curvature R1 and the second radius of curvature R2 are different.

[0040] The planar direction refers to the direction parallel to the plane where the touch structure is located. A basic grid unit refers to the smallest repeatable unit within a metal grid layer. In some traditional display modules, the smallest repeatable unit is such as... Figure 4 As shown in Figure (a), in this embodiment, the basic grid cell is expanded to... Figure 4 The two minimum repeatable elements shown in Figure (a) are used as a basic mesh element. Within this basic mesh element, the two minimum repeatable elements have metal traces with different radii of curvature. Figure 6 The basic grid cell 110 of the illustrated embodiment.

[0041] In this embodiment, by setting the arc curvature radii of the metal traces forming the first grid unit 110a and the second grid unit 110b to be different, interference can be further avoided and diffraction can be reduced.

[0042] It is understood that in other embodiments, the differentiated distribution of the arc-shaped curvature radius is not limited to the above-described arrangement based on the smallest repeatable unit. For example, within a smallest repeatable unit, some metal trace segments can be configured as arcs with a first curvature radius, while other metal trace segments can be configured as arcs with a second curvature radius. That is, different trace segments within the same smallest repeatable unit can have different curvature radii; or, different sections of the same metal trace can also adopt different curvature radii. In other words, as long as the curvature radius of the arc changes in the extension direction of the metal trace, the coherence and periodicity of the reflected light can be disrupted, and all of these fall within the scope of protection of this application.

[0043] Optionally, the ratio of the radius of curvature of the arc to the width of the metal trace 10 is in the range of 0.5 to 2.

[0044] In this embodiment, the width W1 of the metal trace 10 refers to the maximum vertical distance along the width direction between the first side edge L1 and the second side edge L2 along the length direction of the metal trace 10. Since the first side edge L1 and / or the second side edge L2 of the metal trace 10 extend non-linearly, the local width at different locations may vary. In this embodiment, the width of the metal trace refers to the maximum width value corresponding to each location along the trace's length direction. For various non-linear shapes such as sawtooth, wavy, arc, or polygonal shapes, the width W1 refers to this maximum width.

[0045] Taking an arc shape as an example, when the side edge of the metal trace 10 extends in an arc shape, the arc-shaped protrusion will cause the width of the trace in a local area to be greater than the width of other parts. The maximum vertical distance from the first side edge L1 to the second side edge L2 of this protrusion is the width W1 of the metal trace 10 as defined in this application, specifically as follows: Figure 2 as shown in the figure. Assuming that the radius of curvature of the circular arc included in the first side edge and the second side edge is denoted as R, R / W1 is greater than or equal to 0.5 and less than or equal to 2.

[0046] For example, the value of R / W1 may be 0.5, 0.6, 0.7, 1.2, 1.5, 2 and other values. In a specific example, R=3.25μm, the line width W1=5.1μm, and R / W1≈0.64.

[0047] Optionally, the range of the radius of curvature is 2 to 20μm, and the range of the width of the metal trace is 4 to 6μm.

[0048] For example, the width W1 of the metal trace 10 is 4μm, 4.2μm, 4.5μm, 5μm, 5.1μm, 5.2μm, 6μm and other values, and the radius of curvature R is 2μm, 3μm, 3.25μm, 5μm, 10.25μm, 15μm, 20μm and other values.

[0049] Optionally, the thickness of the metal trace 10 is periodically distributed in the length direction, and each thickness variation period includes a plurality of trace segments connected in sequence along the length direction, and the thickness of each trace segment in any thickness variation period is distributed in a stepwise manner.

[0050] In some embodiments, as shown in Figure 7 the figure, Figure 7 is Figure 3 a cross-sectional view of the metal trace at the A-A' position, and the plurality of trace segments 10a include two different thicknesses, which are respectively denoted as a first thickness d11 and a second thickness d12, and in the length direction, each thickness variation period includes one trace segment 10a with the first thickness d11 and one trace segment with the second thickness d12, and the trace segments 10a with the two thicknesses are alternately distributed in sequence.

[0051] In some embodiments, reference is made to Figure 8 , Figure 8 wherein diagram (a) in the figure is a schematic plan structural view of a section of the metal trace, and different gray levels represent different thicknesses, Figure 8 diagram (b) in the figure is an enlarged cross-sectional view of one thickness variation period at the B-B' position, and as shown in Figure 8 the figure, the plurality of trace segments 10a have four different thicknesses, which are respectively denoted as d21, d22, d23 and d24, where d21<d22<d23<d24. In the length direction, each thickness variation period includes 4 trace segments 10a, and along the length direction, the thicknesses of the 4 trace segments 10a are d21, d22, d23, d24 or d24, d23, d22, d21, respectively.

[0052] It should be noted that the stepped distribution in this application refers to the monotonically increasing or decreasing thickness of each trace segment along the length direction within the same thickness change period. That is, the thickness value increases or decreases step by step, and there is a clear thickness jump between adjacent trace segments, but the thickness of each trace segment itself remains consistent.

[0053] Optionally, within each thickness variation cycle, the difference between the maximum and minimum thickness of the trace segment is an integer multiple of half a predetermined wavelength.

[0054] For example, in Figure 7 In the illustrated embodiment, the difference Δd1 between the first thickness d11 and the second thickness d12 satisfies: Δd1 = |d11 - d12| = n × 1 / 2 × λ. Figure 8 In the embodiment shown, the difference between the maximum thickness and the minimum thickness Δd2 satisfies: Δd2=d24-d21=n×1 / 2×λ, where n is a positive integer and λ is a predetermined wavelength.

[0055] The value of the predetermined wavelength λ can be selected according to the actual optical design requirements, such as any value like 550nm, 555nm, or 540nm.

[0056] In this embodiment, trace segments of different thicknesses are arranged alternately along the length direction, which makes the phase difference of reflected light on different thickness segments of incident light diverse. This can effectively break the condition of constant phase difference, thereby minimizing interference phenomena and visibility.

[0057] Optionally, the thickness of each trace segment ranges from 0.4 to 1 μm, and the predetermined wavelength is 550 nm.

[0058] Since the sensitivity of the human eye to visible light varies with wavelength, the human eye is usually most sensitive to green light around 550nm, and the sensitivity decreases significantly when shifting towards red or blue light. In this embodiment, the predetermined wavelength is set to the center wavelength of green light, 550nm, which can reduce the visibility of metal traces to the greatest extent in the wavelength band that the human eye is most sensitive to.

[0059] It is understood that 550nm is only a preferred example of this application, and those skilled in the art can also choose other wavelengths as the predetermined wavelength according to actual needs. This disclosure does not limit it.

[0060] For example, in Figure 7 In the embodiment shown, d11=nλ, d12=nλ+1 / 2λ. If λ=550nm and n=1, then d11=550nm=0.55μm and d12=550nm+275nm=0.825μm.

[0061] For example, in Figure 8In the illustrated embodiment, d21=nλ, d22=nλ+1 / 8λ, d23=nλ+1 / 4λ, d24=nλ+1 / 2λ. If λ=550nm and n=1, then d21=0.55μm, d22=0.61875μm, d23=0.6875μm, and d24=0.825μm.

[0062] It should be noted that the ideal value is that the difference between the maximum and minimum thickness is an integer multiple of 550nm. However, in the actual fabrication process, due to factors such as process errors, the actual difference between the maximum and minimum thickness may deviate from the ideal value. For example, the actual deviation may fluctuate by 30nm (±0.03μm) around an integer multiple of 550nm. This still falls within the protection range of the difference being an integer multiple of the predetermined wavelength in this application. In other words, the thickness difference being an integer multiple of the predetermined wavelength in this application should be understood as being based on this theoretical value as the design center, allowing reasonable fluctuations within the range of process errors.

[0063] In some embodiments, the metal trace 10 may be configured as a non-linear structure, and the thickness of the metal trace 10 may be improved to have at least two thicknesses along its length.

[0064] For example, please refer to Figure 9 , Figure 9 Figure (a) is a schematic diagram of another embodiment of the metal trace, and Figure (b) is a cross-sectional view of the metal trace at position C-C'. Figure 9 As shown, in this embodiment, the first side edge L1 and the second side edge L2 of the metal trace 10 extend in a non-linear manner in the length direction, and each trace segment has two thicknesses.

[0065] Understandable, Figure 9 The illustrated embodiment is merely an exemplary combination scheme of this application. The non-linear shape can be any one or a combination of sawtooth, wavy, arc, and polygonal shapes, and its undulation amplitude and period can be uniform or irregular. The at least two thicknesses can be two, three, or more, and the arrangement of each thickness can be periodic or non-periodic, and the thickness difference can be equal or unequal. The non-linear shape and the multiple thicknesses are independent of each other and can be arbitrarily combined according to actual design requirements, as long as the first side edge and / or the second side edge extend in a non-linear shape, and / or the metal trace has at least two different thicknesses along the length direction. This embodiment does not limit these requirements.

[0066] Optionally, the metal mesh layer includes a first metal layer M1, an insulating layer TLD, and a second metal layer M2 stacked sequentially. Both the first metal layer M1 and the second metal layer M2 are provided with multiple metal traces 10. In the top view of the metal mesh layer, the metal traces 10 in the first metal layer M1 and the metal traces 10 in the second metal layer M2 are arranged in an alternating manner to form a mesh pattern with multiple hollow areas.

[0067] For example, please refer to Figures 10 to 12 , Figure 10 This is a schematic diagram of the film structure of one embodiment of the metal mesh layer. Figure 11 This is a schematic diagram of a planar structure of an embodiment of a metal mesh layer. Figure 12 This is a schematic diagram of a planar structure of another embodiment of the metal mesh layer. Specifically, the metal traces 10 in the first metal layer M1 form multiple first touch electrodes (e.g., Rx electrodes), which are arranged sequentially along the direction of the first plane. The metal traces 10 in the second metal layer M2 form multiple second touch electrodes, which are arranged sequentially along the direction of the second plane. The directions of the first and second planes are parallel to the plane where the touch structure is located, and they are intersected. Within each first touch electrode, all metal traces are electrically continuously connected, and an isolation point is provided between adjacent first touch electrodes to achieve electrical disconnection. Correspondingly, within each second touch electrode, all metal traces are electrically continuously connected, and an isolation point is provided between adjacent second touch electrodes.

[0068] From a top-down view, the first touch electrode in the first metal layer M1 and the second touch electrode in the second metal layer M2 are arranged in an alternating pattern. Electrical isolation is achieved between the first metal layer M1 and the second metal layer M2 through an insulating layer TLD, and no electrical connection is provided between the first touch electrode and the second touch electrode. The metal traces of the first and second touch electrodes together enclose several hollow areas. Multiple sub-pixels are set within each hollow area, and the metal traces surround all the sub-pixels within the hollow area. The sub-pixels are located in the light-transmitting area of ​​the hollow area and are not obstructed by the metal traces.

[0069] For example, in the embodiments of this application, each pixel P includes three sub-pixels: R, G, and B. Figure 11 and Figure 12 Different sizes of sub-pixel graphics are used, corresponding to three types of sub-pixels: R, G, and B. Figure 11 In the first metal layer M1 shown, each hollow area formed by the metal traces 10 contains 4 pixels P, and each pixel P includes three sub-pixels: R, G, and B. That is, each hollow area contains multiple sets of RGB sub-pixels, and the metal traces surround all the sub-pixels within the hollow area. Figure 12In the second metal layer M2 shown, each cutout area formed by the metal traces is equipped with a pixel P. The pixel P also contains three sub-pixels: R, G, and B. The metal traces surround and enclose this group of RGB sub-pixels in the cutout area.

[0070] It should be noted that, Figure 11 and Figure 12 All are top-view schematic diagrams of the first metal layer M1 and the second metal layer M2 superimposed. In order to facilitate the illustration of the interlacing relationship of the two electrode projections, some traces in the schematic diagrams are drawn with schematic gaps. These gaps are only for illustration purposes and do not represent a physical break within the same touch electrode in the actual layout. In the actual layout, the metal traces within the same touch electrode remain continuously conductive.

[0071] Optionally, in each minimum repeatable unit within the metal mesh layer, the length of the metal trace 10 is greater than 50 micrometers. Specifically, within each minimum repeatable unit, the length of the metal trace 10 is related to the number of pixels P contained in that unit and the sub-pixel density; the more pixels P in the unit and the denser the sub-pixel arrangement, the greater the length of the metal trace 10 within the corresponding minimum repeatable unit. For example, in... Figure 11 In the example shown, along the horizontal direction X, the trace length a1 within the minimum repeatable cell is 300 μm, and along the vertical direction Y, the trace length a2 within the minimum repeatable cell is 122 μm. Figure 12 In the example shown, the trace length a3 in the smallest repeatable cell along the horizontal direction X is 70.8 μm.

[0072] Based on the same inventive concept, this disclosure also provides a display panel, including a display substrate and a touch structure as described above. The touch structure is disposed on the light-emitting side of the display substrate. The display substrate includes a plurality of pixel regions distributed in an array. Any hollow area of ​​the metal mesh layer in the touch structure corresponds to at least one pixel region on the display substrate.

[0073] The display substrate in this embodiment can be an OLED display substrate, but it can also be set to other types according to actual needs. For example, the display substrate can also be an active matrix organic light-emitting diode (AMOLED) display substrate, a quantum dot light-emitting diode (QLED) display substrate, a micro light-emitting diode (Micro LED) display substrate, etc.

[0074] The pixel area distributed in the array in the display substrate is the same as the area where pixel P is located as shown above. In a plane parallel to the display substrate, the metal traces in the metal mesh layer are arranged around pixel P, that is, pixel P is located in the area where the cutout area is located.

[0075] In related technologies, one common method to improve the visibility of FMLOC display panels is to change the periodic arrangement of the metal mesh. However, this method of reducing visibility by adjusting the mesh arrangement often fails to achieve optimal touch functionality. Simultaneously, to mitigate color shift caused by the FMLOC metal mesh at wide viewing angles, the metal traces typically need to be as far away from the pixel area as possible in the horizontal direction to reduce the obstruction and reflection differences of the metal traces on the light emitted from the pixels at different viewing angles. These two requirements are mutually restrictive in actual wiring design, leading to significant challenges in the wiring design of FMLOC metal meshes.

[0076] In this embodiment, the touch structure, by employing a non-linear design for the side edge shape of the metal traces and / or a segmented, differentiated design for the thickness of the metal traces, can disrupt the phase consistency and reflection path of reflected light at the microstructural level of the metal traces without altering the overall arrangement of the metal mesh. This effectively suppresses interference superposition effects and reduces visibility. Furthermore, since this application achieves improved visibility without changing the overall periodic arrangement of the metal mesh, it does not adversely affect the touch functionality. Moreover, the overall wiring path of the metal traces does not require additional adjustments to improve visibility; it can still be routed along the optimal path away from pixel areas, thus also addressing the issue of large-viewing-angle color shift. In other words, this application effectively solves the visibility and large-viewing-angle color shift problems of the FMLOC metal mesh without sacrificing touch performance or increasing wiring complexity by addressing the side edge shape and / or thickness distribution of the traces themselves.

[0077] Based on the same inventive concept, this disclosure also provides a method for preparing a display panel as shown above, such as... Figure 13 As shown, it includes the following steps: Step S101: Provide a display substrate, the display substrate including a plurality of pixel regions distributed in an array; Step S102: A metal mesh layer is prepared on the light-emitting side of the display substrate. Any hollow area of ​​the metal mesh layer corresponds to at least one pixel area on the display substrate. The metal mesh layer includes metal traces. The metal traces have a length direction and a width direction. The metal traces have opposing first side edges and second side edges in the width direction. The first side edges and the second side edges extend in a non-linear manner in the length direction. And / or the metal traces include a plurality of trace segments connected in sequence in the length direction. At least two different thicknesses exist among the plurality of trace segments.

[0078] Optionally, at least two different thicknesses exist among the plurality of trace segments, and the step of fabricating a metal mesh layer on the light-emitting side of the display substrate includes: Step A1: Using a first mask, a first sub-metal trace is formed on the display substrate by a vapor deposition process. The thickness of the first sub-metal trace is the minimum thickness among the plurality of trace segments. The orthographic projection of the first sub-metal trace on the display substrate coincides with the orthographic projection of the metal trace on the display substrate. In this embodiment, the metal mesh layer includes a first metal layer M1 and a second metal layer M2 stacked together. The metal traces of both the first metal layer M1 and the second metal layer M2 can be designed with differentiated thicknesses. In specific fabrication, both the first metal layer M1 and the second metal layer M2 can be fabricated using a step-by-step process with multiple photomasks and multiple vapor depositions. The fabrication principles and processes of the two metal layers are exactly the same. The following describes in detail the differentiated thickness fabrication steps of the metal traces using the first metal layer M1 as an example.

[0079] Specifically, a first mask is used to perform full-surface vapor deposition of the basic thin metal traces of the first metal layer M1. A first mask with a pattern matching the outline of the metal traces within the first metal layer M1 is selected, and a first sub-metal trace is formed on the light-emitting side of the display substrate using a vacuum vapor deposition process. The thickness of the first sub-metal trace is the minimum thickness among all trace segments, and the orthographic projection of the first sub-metal trace on the display substrate completely coincides with the orthographic projection of the final formed complete metal trace within the first metal layer M. In this step, the entire area of ​​the metal traces in the first metal layer M1 is uniformly vapor-deposited, resulting in a continuous structure of uniform thickness for the entire metal trace. This design ensures the continuity of the metal traces from a process perspective, avoiding the risk of breakage that can occur with independent segmented fabrication processes.

[0080] Step A2 involves using a second mask to cover a portion of the first sub-metal trace, and then using a vapor deposition process to thicken the uncovered area. This thickening process is performed at least once, so that the areas that have undergone different thickening processes have different thicknesses, thereby forming multiple trace segments distributed along the length direction and having at least two thicknesses.

[0081] In this step, a suitable combination of second masks is used to complete the graded thickening evaporation of the local area of ​​the first metal layer M1. Corresponding to the number of thicknesses set for the metal traces, a corresponding number of second masks with different masking patterns can be matched. Through multiple layers of evaporation thickening, two or more different thicknesses can be formed. Specifically, if the metal traces need to be prepared with N thicknesses (N≥2), then based on the minimum thickness of the first sub-metal trace, N-1 sets of second masks with different patterns are configured. Different preset trace areas are sequentially masked and graded thickened, so that different areas of the traces are superimposed with metal layers of different thicknesses, ultimately forming a multi-gradient differentiated thickness structure.

[0082] Taking the metal trace with two thicknesses as an example, only one set of second masks is needed to complete the processing: select a second mask with a partial masking pattern, accurately mask a preset area of ​​the formed first sub-metal trace, and only leave the trace area that needs to be thickened exposed; then, the exposed trace area that is not masked by the second mask is thickened by a second vapor deposition process.

[0083] This embodiment employs a differentiated forming logic with two mask partitioning processes, performing only one secondary thickening process to create two thickness structures for the metal traces in the first metal layer M1: the trace area shielded by the second mask and not subjected to secondary vapor deposition retains the minimum thickness of the first sub-metal trace; the trace area not shielded and subjected to secondary vapor deposition is superimposed to form a larger trace thickness. The final formed metal trace has two different thicknesses distributed along its length, and the entire trace can maintain continuous conductivity through the complete first sub-metal trace. The thickened area is only a surface superposition structure, which does not disrupt the overall connectivity of the trace and has no process breaks.

[0084] Obviously, the above embodiments of this disclosure are merely examples for clearly illustrating this disclosure, and are not intended to limit the implementation of this disclosure. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. Any obvious variations or modifications derived from the technical solutions of this disclosure are still within the protection scope of this disclosure.

Claims

1. A touch structure, characterized in that, Includes a metal mesh layer, the metal mesh layer including metal traces having a length direction and a width direction, the metal traces having opposing first and second side edges in the width direction, the first and second side edges extending non-linearly in the length direction; and / or The metal trace includes multiple trace segments connected in sequence along its length, and at least two different thicknesses exist among the multiple trace segments.

2. The touch structure according to claim 1, characterized in that, The non-linear shape is at least one of the following: sawtooth, wavy, arc, or polygonal.

3. The touch structure according to claim 2, characterized in that, The non-linear shape is an arc shape, and the first side edge and the second side edge include a plurality of arc shapes connected in sequence in the length direction, wherein there are at least two different radii of curvature among the plurality of arc shapes.

4. The touch structure according to claim 3, characterized in that, The metal mesh layer includes multiple basic mesh units arranged repeatedly along the planar direction. Each basic mesh unit includes a first mesh unit and a second mesh unit arranged adjacent to each other. The arc shape of the metal trace forming the first mesh unit has a first radius of curvature, and the arc shape of the metal trace forming the second mesh unit has a second radius of curvature. The first radius of curvature and the second radius of curvature are different.

5. The touch structure according to claim 3 or 4, characterized in that, The ratio of the radius of curvature of the arc to the width of the metal trace is in the range of 0.5 to 2.

6. The touch structure according to claim 3 or 4, characterized in that, The radius of curvature ranges from 2 to 20 μm, and the width of the metal trace ranges from 4 to 6 μm.

7. The touch structure according to claim 1, characterized in that, The thickness of the metal trace is periodically distributed along the length direction. Each thickness variation period includes multiple trace segments connected sequentially along the length direction. The thickness of each trace segment is distributed in a stepped manner within any thickness variation period.

8. The touch structure according to claim 7, characterized in that, Within each thickness variation cycle, the difference between the maximum and minimum thickness of the trace segment is an integer multiple of half the predetermined wavelength.

9. The touch structure according to claim 8, characterized in that, The thickness of each trace segment ranges from 0.4 to 1 μm, and the predetermined wavelength is 550 nm.

10. The touch structure according to claim 1, characterized in that, The metal mesh layer includes a first metal layer, an insulating layer, and a second metal layer stacked sequentially. Multiple metal traces are provided in both the first metal layer and the second metal layer. In the top view of the metal mesh layer, the metal traces in the first metal layer and the metal traces in the second metal layer are arranged in an alternating pattern to form a mesh pattern with multiple hollow areas.

11. A display panel, characterized in that, The device includes a display substrate and a touch structure as described in any one of claims 1 to 10, wherein the touch structure is disposed on the light-emitting side of the display substrate, the display substrate includes a plurality of pixel regions distributed in an array, and any hollow area of ​​the metal mesh layer in the touch structure corresponds to at least one pixel region on the display substrate.

12. A method for manufacturing a display panel, characterized in that, Includes the following steps: A display substrate is provided, the display substrate comprising a plurality of pixel regions arranged in an array; A metal mesh layer is fabricated on the light-emitting side of the display substrate. Any cutout area of ​​the metal mesh layer corresponds to at least one pixel region on the display substrate. The metal mesh layer includes metal traces, which have a length direction and a width direction. The metal traces have opposing first and second side edges in the width direction, wherein: The first side edge and the second side edge extend in a non-linear manner along the length direction; and / or The metal trace comprises a plurality of trace segments connected in sequence along its length, and at least two different thicknesses exist among the plurality of trace segments.

13. The method for manufacturing a display panel according to claim 12, characterized in that, The step of fabricating a metal mesh layer on the light-emitting side of the display substrate includes: At least two different thicknesses exist among the plurality of trace segments. Using a first mask, a first sub-metal trace is formed on the display substrate by a vapor deposition process. The thickness of the first sub-metal trace is the minimum thickness among the plurality of trace segments. The orthographic projection of the first sub-metal trace on the display substrate coincides with the orthographic projection of the metal trace on the display substrate. A portion of the first sub-metal trace is masked using a second mask, and the unmasked area is thickened using a vapor deposition process. The thickening process is performed at least once, so that the areas that have undergone different thickening processes have different thicknesses, thereby forming multiple trace segments distributed along the length direction and having at least two thicknesses.

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