Optical functional layer and manufacturing method therefor, and display device

Abstract

An optical functional layer and a manufacturing method therefor, and a display device. The optical functional layer (100) is used for being arranged on a display screen (1001). The optical functional layer (100) comprises a light-transmitting base layer (1) and an anti-glare layer (2); the anti-glare layer (2) is arranged on a first surface (11) of the light-transmitting base layer (1). The anti-glare layer (2) comprises a plurality of convex portions (21); the surfaces of the plurality of convex portions (21) facing away from the light-transmitting base layer (1) together form an anti-glare surface (G). With the first surface (11) of the light-transmitting base layer (1) as a reference face, the absolute value of the tangent slope of any position on the anti-glare surface (G) is less than or equal to 0.1. The optical functional layer (100) can effectively avoid the problem of cracking, and has good bending ability and wear resistance.

Description

An optical functional layer and its manufacturing method, and a display device.

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410999362.X, filed on July 23, 2024, entitled "Optical Functional Layer and Manufacturing Method Thereof, Display Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of optical device technology, and in particular to an optical functional layer and its manufacturing method, and a display device. Background Technology

[0004] When an external light source shines on the screen of a display device, the light undergoes specular reflection, producing strong reflected light, also known as glare. Glare can interfere with the user's vision, making it difficult to see the screen clearly and affecting the visual health of the display device. In related technologies, displays typically use anti-glare glass (AG glass) as the outermost layer to reduce glare; however, AG glass is prone to cracking and failure during use, failing to meet the higher requirements of display devices. Summary of the Invention

[0005] This invention provides an optical functional layer, its manufacturing method, and a display device. The optical functional layer can effectively avoid cracking and has good bending ability and wear resistance.

[0006] In a first aspect, the present invention provides an optical functional layer for use on a display screen. The optical functional layer includes a light-transmitting substrate and an anti-glare layer. The anti-glare layer is disposed on a first surface of the light-transmitting substrate and includes multiple protrusions. The surfaces of the multiple protrusions facing away from the light-transmitting substrate together constitute an anti-glare surface. Taking the first surface of the light-transmitting substrate as a reference plane, the absolute value of the tangent slope at any position on the anti-glare surface is less than or equal to 0.1.

[0007] It should be noted that, taking the first surface of the light-transmitting substrate as the reference plane, the tangent slope at any point on the anti-glare surface specifically refers to the tangent value of the angle between the tangent at any point on the anti-glare surface and the reference plane. The tangent slope at any point on the anti-glare surface reflects the degree of inclination of the anti-glare surface at that location.

[0008] The optical functional layer provided in the above embodiments has an anti-glare surface. External light entering the anti-glare surface is unlikely to undergo regular total internal reflection, thus achieving an anti-glare effect. Furthermore, any position on the anti-glare surface has a small tilt angle, preventing multiple protrusions from squeezing each other when the optical functional layer is bent, effectively avoiding cracking. The anti-glare surface also possesses good mechanical properties, reducing stress concentration on the protrusions under stress and improving the wear resistance and service life of the anti-glare surface. The optical functional layer in the above embodiments has good bending ability and wear resistance.

[0009] In conjunction with the first aspect, in some possible implementations, the absolute value of the rate of change of slope at any location on the anti-glare surface is less than or equal to 0.5. The rate of change of slope is a quantity that describes the speed at which the slope of a curve changes at various locations. Mathematically, the rate of change of slope at a point on a curve is equal to the second derivative of the curve at that point.

[0010] In the above embodiments, the slope change rate at each point on the anti-glare surface is relatively gentle, and there is a smooth transition between different positions on the anti-glare surface, without sharp positions with abrupt changes in inclination. Taking the apex of the protrusion as an example, the smooth transition at the apex increases the contact area between the protrusion and the outside, thereby reducing stress concentration at the apex and improving the wear resistance of the anti-glare surface. Taking the valley point of the protrusion as an example, adjacent protrusions can smoothly transition and connect. When the optical functional layer bends, the bending stress on adjacent protrusions near the valley point can be effectively reduced, making the optical functional layer less prone to breakage, thereby improving the bending capability of the optical functional layer.

[0011] In conjunction with the first aspect, in some possible implementations, the position on each protrusion with the largest distance from the reference surface is the vertex of that protrusion. Among the plurality of protrusions, the height difference between the vertices of any two protrusions in the height direction is less than or equal to 1 μm, where the height direction refers to the direction perpendicular to the reference surface. This ensures good consistency in the height of the plurality of protrusions, increasing the number of protrusions in contact with the external structure, thereby increasing the contact area under stress, reducing stress concentration, and improving the wear resistance and service life of the anti-glare surface.

[0012] In conjunction with the first aspect, in some possible implementations, the position on each protrusion with the greatest distance from the reference surface is the vertex of the protrusion, and the position on each protrusion with the smallest distance from the reference surface is the valley point of the protrusion. The distance between the vertex and the valley point of each protrusion in the height direction is 0.1µm-10µm, where the height direction refers to the direction perpendicular to the reference surface. The protrusions in this embodiment achieve good light dispersion performance, giving the optical functional layer good anti-glare capability. The protrusions have a small thickness, resulting in good mechanical properties and reducing the impact of the optical functional layer on the display optics of the screen.

[0013] In conjunction with the first aspect, in some possible implementations, the maximum dimension of each protrusion in the direction parallel to the reference plane is 5-100 μm. The protrusions in this embodiment have a size much smaller than the visible size of the human eye, which can reduce the impact of the optical functional layer on the display optics of the display screen.

[0014] In conjunction with the first aspect, in some possible implementations, the protrusions are formed as non-spherical particles such as ellipsoidal particles, convex lens-shaped particles, and disc-shaped particles. For example, the edges of the protrusions that meet adjacent protrusions are formed into irregular shapes. The protrusions in this embodiment have more disordered shapes, resulting in better anti-glare performance.

[0015] In conjunction with the first aspect, in some possible implementations, the light transmittance of the anti-glare layer is greater than or equal to 90%. The anti-glare layer has good light transmittance for light emitted from inside the display screen, reducing the influence of the optical functional layer on the display screen's display light.

[0016] In conjunction with the first aspect, in some possible implementations, the haze of the anti-glare layer is less than or equal to 5%. The anti-glare layer has good gloss, transparency, and imaging quality.

[0017] In conjunction with the first aspect, in some possible implementations, the hardness of the anti-glare layer is greater than or equal to 1H, so as to improve the wear resistance of the anti-glare surface and increase the service life of the optical functional layer.

[0018] In conjunction with the first aspect, in some possible implementations, the tensile modulus of the anti-glare layer is greater than or equal to 5 GPa. The anti-glare layer in this embodiment has a large tensile modulus, making it less prone to deformation during use (e.g., when a user touches the display screen), thus ensuring the stable display function of the screen.

[0019] In conjunction with the first aspect, in some possible implementations, the elongation at break of the anti-glare layer is greater than or equal to 3%. The anti-glare layer has a large elongation at break, good flexibility and elasticity, and thus good bending performance.

[0020] In conjunction with the first aspect, in some possible implementations, the material of the light-transmitting substrate is any one of polyethylene terephthalate (PET), polycarbonate (PC), colorless polyimide (CPI), or ultra-thin glass (UTG).

[0021] In conjunction with the first aspect, in some possible implementations, the anti-glare layer is made of acrylic resin or epoxy resin.

[0022] In conjunction with the first aspect, in some possible implementations, the optical functional layer further includes an anti-reflection layer covering the anti-glare surface. This anti-reflection layer reduces the reflectivity of light incident on the anti-glare layer, allowing external light to enter and be absorbed by multiple protrusions within the anti-glare layer, thereby improving anti-glare performance. For example, the thickness of the anti-reflection layer is less than or equal to 500 nm to reduce the overall thickness of the optical functional layer, facilitating bending of the optical functional layer.

[0023] In conjunction with the first aspect, in some possible embodiments, the antireflective layer comprises a high-refractive-index layer and a low-refractive-index layer stacked on top of each other. The high-refractive-index layer has a refractive index greater than 1.65, and the low-refractive-index layer has a refractive index less than 1.55. The stacked high-refractive-index and low-refractive-index layers reduce the reflectivity of light incident on the anti-glare layer. Exemplarily, the high-refractive-index layer comprises high-refractive-index particles, such as zirconium oxide or aluminum oxide. Exemplarily, the low-refractive-index layer comprises hollow silicon dioxide particles.

[0024] In conjunction with the first aspect, in some possible embodiments, the optical functional layer further includes an anti-fingerprint layer covering the anti-glare surface. In other possible embodiments, the optical functional layer includes an anti-reflection layer and an anti-fingerprint layer, with the anti-reflection layer covering the anti-glare surface and the anti-fingerprint layer located on the side of the anti-reflection layer opposite to the anti-glare layer. The anti-fingerprint layer reduces fingerprint adhesion, making it easier to clean dirt from the display surface.

[0025] In some possible implementations, the thickness of the anti-fingerprint layer is less than 50 nm to reduce the overall thickness of the optical functional layer, which facilitates bending of the optical functional layer.

[0026] In a second aspect, the present invention provides a method for manufacturing an optical functional layer for use in any of the above possible embodiments of the optical functional layer, the method comprising:

[0027] Layered adhesive material is arranged on the surface of a light-transmitting base layer, and then pressed onto the adhesive material using a mold to form protrusions.

[0028] The manufacturing method described above can easily and quickly manufacture the optical functional layer provided in the embodiments of the present invention.

[0029] In some possible implementations, the above-described manufacturing method specifically includes: depositing a layered adhesive material (e.g., UV-curable or thermoplastic curable adhesive) on the surface of a light-transmitting substrate (e.g., made of any of PET, PC, CPI, or UTG); then, arranging the layered adhesive material toward a mold with recesses, causing the mold to compress the layered adhesive material; subsequently, irradiating the material with light from the side opposite to the deposited layered adhesive material on the light-transmitting substrate to cure the adhesive material, or baking the layered adhesive material to cure it. Finally, the mold is removed. Thus, this manufacturing method forms an anti-glare surface of a specific shape and size on the adhesive material through a mold-pressing process.

[0030] In conjunction with the second aspect, in some possible implementations, the manufacturing method further includes:

[0031] An antireflective layer is formed by depositing at least multiple layers of inorganic materials on the anti-glare surface in a vacuum environment using evaporation or sputtering methods; or

[0032] Hollow silica spheres are coated onto the anti-glare surface to form an anti-reflective layer.

[0033] In conjunction with the second aspect, in some possible implementations, the manufacturing method further includes:

[0034] An anti-fingerprint layer is formed by vacuum coating or wet spraying on the side of the anti-reflective layer opposite to the anti-fingerprint layer.

[0035] Thirdly, the present invention provides a display device, which includes a display screen and an optical functional layer as described in any of the above possible embodiments, the optical functional layer being disposed on the display screen. Attached Figure Description

[0036] Figure 1 is a schematic diagram of the structure of a display device provided in an embodiment of the present invention;

[0037] Figure 2 is a cross-sectional view of an optical functional layer provided in the first embodiment of the present invention after being cut along a direction perpendicular to the first surface;

[0038] Figure 3 is a cross-sectional view of an optical functional layer provided in the second embodiment of the present invention after being cut along a direction perpendicular to the first surface;

[0039] Figure 4 is a top view of an optical functional layer provided in the third embodiment of the present invention;

[0040] Figure 5 is a schematic diagram of the anti-glare surface of an optical functional layer provided in the third embodiment of the present invention after being cut along a direction perpendicular to the first surface;

[0041] Figure 6 is a cross-sectional view of an optical functional layer provided in the fourth embodiment of the present invention after being cut along a direction perpendicular to the first surface;

[0042] Figure 7 is a flowchart of a method for manufacturing an optical functional layer according to an embodiment of the present invention;

[0043] Figure 8 is a flowchart of a method for manufacturing an optical functional layer according to another embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0045] Hereinafter, the terms "first," "second," etc., are used for descriptive convenience 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] In embodiments of the present invention, unless otherwise expressly specified and limited, the term "electrical connection" can refer to a direct electrical connection or an indirect electrical connection via an intermediate medium. Words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary" or "for example" in embodiments of the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0047] In embodiments of the invention, the directional indications used to explain the structure and movement of different components, such as up, down, left, right, front, and back, are relative. These indications are appropriate when the components are in the positions shown in the figures. However, if the description of the component positions changes, these directional indications will also change accordingly. It should also be noted that in embodiments of the invention, the same reference numerals represent the same component or part. For the same parts in embodiments of the invention, the reference numerals may only be used to indicate one part or component as an example in the figures. It should be understood that the reference numerals also apply to other identical parts or components.

[0048] First, a unified explanation of the terminology that may be involved in the embodiments of the present invention will be provided.

[0049] Slope: The slope is a measure of the inclination of a straight line (or the tangent line of a curve) about the (horizontal) coordinate axis. It is usually expressed as the tangent of the angle between the straight line (or the tangent line of a curve) and the (horizontal) coordinate axis. Mathematically, the slope of a point on a straight line (or curve) is equal to the first derivative of the straight line (or curve) at that point.

[0050] Rate of change of slope: The rate of change of slope is a quantity that describes the speed at which the slope of a curve changes at various points. From a mathematical perspective, the rate of change of slope at a point on a curve is equal to the second derivative of the curve at that point.

[0051] Diffuse reflection: When a beam of parallel light is projected onto a relatively rough object, the reflected light is no longer parallel but travels in all directions. This phenomenon is called diffuse reflection. Diffusely reflected light travels in all directions, and the reflected light is softer and less glaring.

[0052] Light transmittance: Light transmittance represents the ability of light to pass through a medium; it is the percentage of luminous flux passing through a transparent or translucent body relative to the incident luminous flux. When a beam of parallel monochromatic light passes through a uniform, non-scattering medium, part of the light is absorbed, part passes through the medium, and part is reflected by the surface of the medium. Light transmittance indicates the efficiency of light transmission in display devices, and it directly affects the visual effect of a touchscreen.

[0053] Haze: Haze is the percentage of transmitted light intensity that deviates from the incident light angle by more than 2.5° out of the total transmitted light intensity. Specifically, when a beam of parallel light from a standard light source is perpendicularly shone onto a transparent or translucent film, sheet, or plate, the parallel light undergoes light scattering within the material and on its surface. Haze is the percentage of the luminous flux of scattered light deviating from the incident direction by more than 2.5° to the luminous flux transmitted through the material. Higher haze indicates a decrease in film gloss, transparency, and image quality. Haze is an important parameter describing the optical transparency of transparent or translucent materials.

[0054] Hardness: The ability of a material to resist the indentation of a harder object on its surface is called hardness. It is the localized resistance of a solid to the intrusion of external objects and is an indicator for comparing the hardness of various materials.

[0055] Tensile modulus: Tensile modulus refers to the elasticity of a material when stretched. The value of tensile modulus is the ratio of the force required to stretch the material by a unit length along the central axis to the cross-sectional area of ​​the material. Tensile modulus is a physical quantity that describes the ability of a solid material to resist deformation.

[0056] Elongation at break: Elongation at break is the ratio of the displacement of a material at the point of fracture to its original length, expressed as a percentage. It is an indicator of a material's flexibility and elasticity. A higher elongation at break indicates better flexibility and elasticity.

[0057] Steel wool abrasion test: This is a method used to test the abrasion resistance of material surfaces. The test involves rubbing steel wool back and forth on the material surface under a specific load, and evaluating the abrasion resistance of the material by measuring the difference in the water droplet angle before and after friction.

[0058] The following section will describe in detail, with reference to the accompanying drawings, the optical functional layer and its manufacturing method provided by the embodiments of the present invention, as well as the specific structure of the display device.

[0059] This invention provides a display device 1000, which can be a mobile phone, tablet computer, laptop computer, personal digital assistant (PDA), camera, personal computer, laptop computer, in-vehicle device, wearable device, watch, augmented reality (AR) glasses, AR headset, virtual reality (VR) glasses, or VR headset, etc. For example, the display device 1000 can be a portable display device 1000.

[0060] Referring to Figure 1, which is a schematic diagram of the structure of a display device 1000 provided in an embodiment of the present invention, the display device 1000 is a mobile phone in the embodiment shown in Figure 1. In some embodiments, the display device 1000 includes a display screen 1001, which is used to receive electrical signals and optically display information for user viewing. The display screen 1001 in the display device 1000 may be used only for optical display, or the display screen 1001 may also integrate a touch module, allowing the user to input information or perform specific functions by touching the display screen 1001. In some embodiments, the display device 1000 is a foldable mobile phone, which has a first screen and a second screen. The first screen and the second screen can be brought closer together or moved away from each other via a hinge 1006, so that the foldable mobile phone has a folded state and an unfolded state.

[0061] The display device 1000 may also include components such as a back cover 1002, a control circuit board (not shown), a battery (not shown), and a camera. For example, the display screen 1001 may be combined with the back cover 1002 to jointly form the outer contour of the display device 1000. The back cover 1002 can be used to protect the internal electronic components (such as circuit boards, batteries, etc.) of the display device 1000. In some embodiments, the back cover 1002 may include a back cover and a middle frame, with the middle frame fixed to the back cover. Exemplarily, the middle frame can be fixedly connected to the back cover by adhesive. The middle frame may also be integrally formed with the back cover, i.e., the middle frame and the back cover are a single integral structure. The display screen 1001 may be connected to the middle frame by, for example, adhesive bonding. The aforementioned components such as the circuit board and battery can be accommodated within the space formed by the display screen 1001, the middle frame, and the back cover. The circuit board may include flexible circuit boards, rigid circuit boards, etc. Power devices such as chips and controllers may be disposed on the circuit board.

[0062] For example, the display device 1000 may also include a front-facing camera 1003, and a camera hole may be provided on the display screen 1001. The front-facing camera 1003 can acquire image information from the light-emitting side of the display screen 1001 through the camera hole. In some other examples, the display device 1000 may not include a battery, for example, it can be directly connected to an external power source. It is understood that Figure 1 only schematically shows some components of the display device 1000, and the actual shape, size, position, and structure of these components are not limited to Figure 1 and the following figures.

[0063] In some embodiments, the display device 1000 is a foldable display device, such as a foldable mobile phone or a foldable tablet computer. Exemplarily, the foldable display device includes a first portion 1004, a second portion 1005, a display screen 1001, and a hinge 1006. The first portion 1004 and the second portion 1005 are movably connected via the hinge 1006, and the display screen 1001 is supported on the first portion 1004 and the second portion 1005. The foldable display device 1000 has an unfolded state and a folded state. In the unfolded state, the first portion 1004, the hinge 1006, and the second portion 1005 are located or approximately located in the same plane, and the display screen 1001 is supported on the first portion 1004, the hinge 1006, and the second portion 1005, and the display screen 1001 is in a flat, unfolded state. In the folded state, the first portion 1004 and the second portion 1005 are brought closer together via the hinge 1006 so that the first portion 1004 and the second portion 1005 overlap, and the display screen 1001 is bent. In some embodiments, the display screen 1001 is located between the first portion 1004 and the second portion 1005. In other embodiments, the display screen 1001 covers the outside of the first portion 1004, the hinge 1006, and the second portion 1005. Therefore, the display screen 1001 used in the foldable display device 1000 needs to have a certain degree of bending capability and elasticity to adapt to both unfolded and folded states.

[0064] In some embodiments, the display device 1000 includes a display screen 1001 and a flexible circuit board (not shown). The flexible circuit board is electrically connected to the display screen 1001 to provide electrical signals to the display screen 1001. Exemplarily, a first end of the flexible circuit board may be electrically connected to the display screen 1001, and the other end of the flexible circuit board may be provided with a connector for connecting to an external controller or power supply, thereby facilitating the installation and removal of the display screen 1001. In embodiments where the display screen 1001 is used in the display device 1000, the flexible circuit board of the display screen 1001 module may be connected between the display screen 1001 and the control circuit board of the display device 1000 to facilitate signal transmission.

[0065] The display screen 1001 in this embodiment of the invention can be a flexible display screen or a rigid display screen. For example, the display screen 1001 can be any one of an organic light-emitting diode (OLED) display screen, an active-matrix organic light-emitting diode (AMOLED) display screen, a mini organic light-emitting diode (MLED) display screen, a micro organic light-emitting diode (MLED) display screen, a quantum dot light-emitting diode (QLED) display screen, and a liquid crystal display (LCD).

[0066] In some usage scenarios, ambient light enters the display screen 1001 and is reflected before escaping. This reflected light can obscure the content on the display screen 1001. In some embodiments, a polarizer is provided within the display screen 1001 to absorb the reflected ambient light. However, since the polarizer is an absorptive type, the light emitted from the display screen 1001 is also absorbed, thus reducing the light extraction efficiency of the display screen 1001. In other words, while the polarizer enables the display screen 1001 to be visible under ambient light, it also results in low light extraction efficiency. In other embodiments, the industry has proposed a technology that forms a color filter on a thin film encapsulation (CF on TFE, COE) structure. COE technology is a new technology that can replace polarizers. By fabricating the color filter on a thin film encapsulation (TFE) layer, and utilizing the property of the color filter to transmit specific spectral light and absorb other spectral light, ambient light can be suppressed, allowing the display screen 1001 to display clear content even in strong light environments such as outdoors. Furthermore, compared to the technology using polarizers, the color filter has a thinner structure, which is beneficial for making the display screen 1001 thinner and lighter, and achieving flexible display characteristics.

[0067] In some usage scenarios, when light from an external light source shines onto the display screen 1001 of the display device 1000, the light is prone to total internal reflection on the panel of the display screen 1001, resulting in strong reflected light, also known as glare. Glare can interfere with the user's vision, making it difficult for the user to see the screen clearly and affecting the visual health of the display device 1000. In some embodiments, the display screen 1001 includes anti-glare glass (AG glass). AG glass specifically refers to glass with a disordered random structure formed on it through a frosted etching process. This causes light to diffusely reflect between multiple random glass structures, making it difficult for light to undergo regular total internal reflection on the surface of the random glass structures, thereby reducing the interference of light on the user's vision and achieving an anti-glare effect. However, the random glass structure on AG glass often has the problem of excessively sharp surface structures, making AG glass prone to cracking when bent. Furthermore, AG glass has poor wear resistance; its anti-glare surface fails after about 50 steel wool abrasion tests.

[0068] Based on this, embodiments of the present invention provide an optical functional layer 100, which is disposed on a display screen 1001 to replace the conventional AG glass described above, thereby achieving an anti-glare function for the display screen 1001. Exemplarily, the optical functional layer 100 is located on the light-emitting side of the display screen 1001; for example, the optical functional layer 100 covers the polarizer or color filter layer of the display screen 1001. In other embodiments, the optical functional layer 100 is used to cover a glass cover plate of the display screen 1001.

[0069] Figure 2 shows a cross-sectional view of the optical functional layer 100 provided in an exemplary embodiment of the present invention. It should be noted that the structural dimensions shown in the accompanying drawings are not representative of the actual structural dimensions in practical applications. For ease of illustration, the structures shown in the accompanying drawings have certain dimensional proportions that are not intended to limit the scope of the present invention.

[0070] As shown in Figure 2, the optical functional layer 100 includes a light-transmitting substrate 1 and an anti-glare layer 2. The anti-glare layer 2 is disposed on the first surface 11 of the light-transmitting substrate and includes a plurality of protrusions 21. The surfaces of the plurality of protrusions 21 facing away from the light-transmitting substrate 1 together constitute the anti-glare surface G. Taking the first surface 11 of the light-transmitting substrate 1 as the reference plane F, the absolute value of the tangent slope k at any position on the anti-glare surface G is less than or equal to 0.1, that is, it satisfies |k|≥0.01. In some embodiments, the tangent slope k at any position on the anti-glare surface G satisfies the relationship 0.01≤|k|≤0.05.

[0071] Taking the first surface 11 of the light-transmitting base layer 1 as the reference plane F, the slope of the tangent at any position on the anti-glare surface G specifically refers to the tangent of the angle between the tangent at any position on the anti-glare surface G and the reference plane F. For example, referring to Figure 2, the tangent aa at point A on the anti-glare surface G intersects the first surface 11, which serves as the reference plane F, at an angle α. The slope at point A is the tangent of the angle α. Furthermore, mathematically, the slope at any position on the anti-glare surface G is equal to the first derivative of the anti-glare surface G at that position. In the cross-sectional view shown in Figure 2, the anti-glare surface G can be considered as a curve on that cross-section. The slope at point A on the anti-glare surface G can be obtained by calculating the first derivative of the curve of the anti-glare surface G on that cross-section at point A. In addition, the slope of the tangent at any position on the anti-glare surface G can be obtained in any other way, and this invention does not impose any specific limitations on this.

[0072] In the above embodiment, the anti-glare layer 2 includes a plurality of protrusions 21. The plurality of protrusions 21, which are away from the surface of the light-transmitting base layer 1, together constitute the anti-glare surface G. When external light enters the anti-glare surface G, it undergoes diffuse reflection, that is, it is difficult to undergo regular total internal reflection. The light is refracted and absorbed between the plurality of protrusions 21, thereby reducing the interference of light on the user's vision and achieving a good anti-glare effect.

[0073] The slope of the tangent at any point on the anti-glare surface G reflects the degree of tilt of the anti-glare surface G at that point. In the optical functional layer 100, with the first surface 11 of the light-transmitting base layer 1 as the reference plane F, the absolute value of the tangent slope at any point on the anti-glare surface G is less than or equal to 0.1. Thus, any point on the anti-glare surface G has a small tilt relative to the first surface 11, allowing the protrusions 21 of the anti-glare surface G to transition at a relatively gentle angle. Compared to related technologies where the anti-glare surface has sharp protrusions, these sharp protrusions are prone to positional interference with other protrusions when the anti-glare surface folds, thereby damaging the anti-glare surface. In this embodiment of the invention, the tilt of each point on the anti-glare surface G is low. Even if the optical functional layer 100 bends, adjacent protrusions 21 will not press against each other, effectively preventing cracking of the optical functional layer 100.

[0074] On the other hand, any position on the anti-glare surface G has a smaller inclination angle compared to the first surface 11, which can improve the mechanical properties of the protrusion 21, increase the force-bearing contact area of ​​the protrusion 21, thereby reducing the stress concentration generated by the protrusion 21 under stress, and improving the wear resistance and service life of the anti-glare surface G. For example, in the steel wool wear resistance test of the anti-glare surface G, because any position on the anti-glare surface G has a smaller inclination angle, the steel wool can have a larger actual contact area with the anti-glare surface, the anti-glare surface can disperse stress, reduce the local stress on the protrusion 21, and thus have good wear resistance.

[0075] Therefore, the optical functional layer 100 provided in the above embodiment has an anti-glare surface G, and the protrusions 21 of the anti-glare surface G all have a small inclination. This prevents the multiple protrusions 21 from squeezing each other when the optical functional layer 100 is bent, effectively avoiding cracking. Furthermore, the anti-glare surface G has good mechanical properties, reducing stress concentration on the protrusions 21 under stress and improving the wear resistance and service life of the anti-glare surface G. The optical functional layer 100 in the above embodiment has good bending ability and wear resistance, and has good application prospects. For example, the optical functional layer 100 can be applied in a foldable display device 1000, such as a foldable mobile phone or a foldable tablet computer.

[0076] As shown in Figures 2 and 3, each protrusion 21 has a position with the maximum distance from the reference plane F, namely, the vertex T of the protrusion 21. Each protrusion 21 also has a position with the minimum distance from the reference plane F, namely, the valley point B of the protrusion 21. It should be noted that each protrusion 21 may have more than one vertex T and more than one valley point B, but the distance between each protrusion 21 and the reference plane F has a definite maximum value and a definite minimum value.

[0077] Referring to Figure 4, two adjacent protrusions 21 meet at valley point B. The same protrusion 21 can meet with multiple different protrusions 21 in the circumferential direction. Multiple protrusions 21 meet with each other. In this way, the surfaces of multiple protrusions 21 that are away from the light-transmitting base layer 1 can jointly form an integral anti-glare surface G.

[0078] In some embodiments, the protrusions 21 are formed as non-spherical particles such as ellipsoidal particles, convex lens-shaped particles, and disc-shaped particles. Referring to the top view of the optical functional layer 100 shown in FIG4, in some embodiments, the edges of the protrusions 21 that adjoin adjacent protrusions 21 are formed into irregular shapes. In this way, the protrusions 21 have disordered irregular shapes, which can improve the anti-glare effect of the anti-glare surface G.

[0079] In some embodiments, the absolute value of the rate of change of slope at any location on the anti-glare surface G is less than or equal to 0.5. The rate of change of slope is a quantity describing the speed of change of the slope at each location on a curve. Mathematically, the rate of change of slope at a point on a curve is equal to the second derivative of the curve at that point. In this embodiment, the absolute value of the rate of change of slope at any location on the anti-glare surface G is less than or equal to 0.5. The rate of change of slope at each point on the anti-glare surface G that satisfies this relationship is relatively gentle, and there is a smooth transition between locations on the anti-glare surface G, without sharp locations with abrupt changes in slope.

[0080] Especially at locations where the bending direction of the protrusion 21 changes, for example, where the bending direction of the protrusion 21 changes on both sides of the vertex T / valley point B, its slope undergoes abrupt changes in value. The absolute value of the rate of change of the slope at the vertex T of the protrusion 21 is less than or equal to 0.5; for example, the absolute value of the rate of change of the slope at the vertex T of the protrusion 21 is 0.05-0.3. In this way, the transition of the protrusion 21 at the vertex T is gentle, which can increase the contact area between the protrusion 21 and the outside, thereby reducing the stress concentration of the protrusion 21 at the vertex T and improving the wear resistance of the anti-glare surface G. And the absolute value of the rate of change of the slope at the valley point B of the protrusion 21 is less than or equal to 0.5; for example, the absolute value of the rate of change of the slope at the valley point B of the protrusion 21 is 0.05-0.3. In this way, adjacent protrusions 21 can smoothly transition and connect. When the optical functional layer 100 is bent, the bending stress of adjacent protrusions 21 near the valley point B can be effectively reduced, and the optical functional layer 100 is less likely to break, thereby improving the bending ability of the optical functional layer 100.

[0081] In some embodiments, the distance between the vertex T on each protrusion 21 and the valley point B of the protrusion 21 in the height direction is 0.1µm-10µm, where the height direction refers to the direction perpendicular to the reference plane F (i.e., the first surface 11). For example, as shown in FIG2, the distance H between the vertex T on the protrusion 21 and the valley point B of the protrusion 21 in the height direction is 0.05µm-3µm. In the above embodiments, the protrusion 21 can achieve good light dispersion performance, giving the optical functional layer 100 good anti-glare capability. The protrusion 21 has a small thickness, thus possessing good mechanical properties and reducing the impact of the optical functional layer 100 on the display optics of the display screen 1001.

[0082] In some embodiments, among the plurality of protrusions 21, the height difference in the height direction between any two vertices T of the protrusions 21 is less than or equal to 1 μm. For example, as shown in FIG3, the height difference h in the height direction between the vertex T1 of the first protrusion 21 and the vertex T2 of the second protrusion 21 is less than or equal to 1 μm, for example, the height difference h is 0.01 μm-0.5 μm.

[0083] In the above embodiments, the heights of the multiple protrusions 21 are highly consistent. When in contact with external structures, this increases the number of protrusions 21 in contact, thereby increasing the contact area, reducing stress concentration, and improving the wear resistance and service life of the anti-glare surface G. For example, in the steel wool wear test of the anti-glare surface G, because the heights of the multiple protrusions 21 are close to each other, the steel wool can simultaneously contact different protrusions 21 when in contact with the anti-glare surface, resulting in a larger actual contact area. The anti-glare surface can disperse stress, reduce the local stress on the protrusions 21, and thus exhibit good wear resistance.

[0084] In some embodiments, the maximum dimension of each protrusion 21 in the direction parallel to the reference plane F is 5µm-100µm. It should be noted that the direction parallel to the reference plane F can also be understood as the direction perpendicular to the aforementioned height direction; in other words, the maximum dimension of each protrusion 21 in the direction perpendicular to the height direction is 5µm-100µm. The protrusions 21 satisfying this relationship have dimensions much smaller than the visible size of the human eye, which can reduce the impact of the optical functional layer 100 on the display optics of the display screen 1001.

[0085] Figure 4 is a top view of the optical functional layer 100 provided in an exemplary embodiment of the present invention, wherein the vertical and horizontal axes are labeled with the dimensions (in μm) in the direction. Referring to Figure 4, the maximum dimension of each protrusion 21 in the direction parallel to the reference plane F is the maximum dimension of the edge of each protrusion 21 used to connect with the adjacent protrusion 21. Figure 5 is a schematic diagram of the anti-glare surface G of the optical functional layer 100 provided in an exemplary embodiment of the present invention after being cut along the direction perpendicular to the first surface 11. The vertical axis is labeled with the dimensions (in μm) in the thickness direction perpendicular to the reference plane F, and the horizontal axis is labeled with the dimensions (in μm) in the direction parallel to the reference plane F. Referring to Figure 5, the dimension of the protrusion 21 where the first vertex T is located on the curve in the thickness direction perpendicular to the reference plane F is 1.456 μm, the dimension of the protrusion 21 where the second vertex T is located on the curve in the thickness direction perpendicular to the reference plane F is 1.500 μm, and the height difference between the second vertex T and the first vertex T in the thickness direction perpendicular to the reference plane F is 0.044. Furthermore, the distance between the two valley points B in the horizontal direction of the protrusion 21 where the first vertex T on the curve is located is less than 50 μm.

[0086] The optical functional layer 100 shown in Figures 4 and 5 can maintain its anti-glare performance after 2000 abrasion tests with steel wool, and the optical functional layer 100 can be bent with a bending radius R greater than or equal to 0.8 mm without breaking.

[0087] In some embodiments, the transmittance of the anti-glare layer 2 is greater than or equal to 90%. Transmittance represents the ability of light to pass through a medium. The anti-glare layer 2 that meets this transmittance can have good light transmission performance for the light emitted from inside the display screen 1001, thereby reducing the influence of the optical functional layer 100 on the display light of the display screen 1001.

[0088] In some embodiments, the haze of the anti-glare layer 2 is less than or equal to 5%. Haze is an important parameter describing the optical transparency of transparent or translucent materials. The anti-glare layer 2 that satisfies this relationship has good gloss, transparency, and imaging accuracy, thereby improving the optical performance of the display device 1000.

[0089] In some embodiments, the hardness of the anti-glare layer 2 is greater than or equal to 1H, so as to improve the wear resistance of the anti-glare surface G and increase the service life of the optical functional layer 100.

[0090] In some embodiments, the tensile modulus of the anti-glare layer 2 is greater than or equal to 5 GPa. Tensile modulus is a physical quantity describing the ability of a solid material to resist deformation. In this embodiment, the anti-glare layer 2 has a large tensile modulus, making it less prone to deformation during use and ensuring the stable display function of the display screen 1001. In embodiments where the display screen 1001 includes a touch module, when a user performs touch operations on the display screen 1001, the large tensile modulus of the anti-glare layer 2 can resist deformation or damage to the optical functional layer 100 caused by the user touching the display screen 1001.

[0091] In some embodiments, the elongation at break of the anti-glare layer 2 is greater than or equal to 3%. Elongation at break is an indicator characterizing the softness and elasticity of a material. The anti-glare layer 2 in this embodiment has a large elongation at break, exhibiting good softness and elasticity. When the optical functional layer 100 is bent, the anti-glare layer 2 is less prone to breakage, thus possessing good bending performance, making it suitable for foldable display devices 1000 (e.g., foldable mobile phones or foldable tablets).

[0092] In some embodiments, the anti-glare layer 2 is made of acrylic resin or epoxy resin. Taking acrylic resin as an example, acrylic resin has good light transmittance, haze, hardness and crack resistance, which enables the optical functional layer 100 to have good optical performance and is not easy to break under bending conditions.

[0093] The light-transmitting substrate 1 is made of a material with good light transmission properties. For example, the material of the light-transmitting substrate 1 is any one of polyethylene terephthalate (PET), polycarbonate (PC), colorless polyimide (CPI), or ultra-thin flexible glass (UTG).

[0094] As shown in Figure 6, in some embodiments, the optical functional layer 100 further includes an anti-reflection layer 3, which covers the anti-glare surface G of the anti-glare layer 2. The anti-reflection layer 3 can reduce the reflectivity of light incident on the anti-glare layer, allowing external light to enter the anti-glare layer and be absorbed by multiple protrusions 21 within the anti-glare layer, thereby improving anti-glare performance and enhancing the visibility of the display screen 1001. In some embodiments, the thickness of the anti-reflection layer 3 is less than or equal to 500 nm to reduce the overall thickness of the optical functional layer 100, which facilitates the bending of the optical functional layer 100. It should be noted that the direction of the thickness mentioned here is parallel to the aforementioned height direction.

[0095] In some embodiments, the antireflective layer 3 includes a high-refractive-index layer and a low-refractive-index layer stacked on top of each other. The stacked high-refractive-index layer and low-refractive-index layer reduce the reflectivity of light incident on the anti-glare layer. The high-refractive-index layer has a refractive index greater than 1.65; exemplaryly, it comprises high-refractive-index particles, such as zirconium oxide or aluminum oxide. The low-refractive-index layer has a refractive index less than 1.55; exemplaryly, it comprises hollow silicon dioxide particles.

[0096] In some embodiments, the optical functional layer 100 further includes an anti-fingerprint layer 4. Exemplarily, the anti-fingerprint layer 4 covers the side of the anti-glare layer opposite to the transparent substrate. In embodiments where the optical functional layer 100 includes an anti-reflection layer 3, the anti-fingerprint layer 4 is located on the side of the anti-reflection layer 3 opposite to the anti-glare layer. The anti-fingerprint layer 4 reduces fingerprint adhesion, making it easier to clean dirt from the surface of the display screen 1001.

[0097] In some embodiments, the thickness of the anti-fingerprint layer 4 is less than 50 nm to reduce the overall thickness of the optical functional layer 100, thereby facilitating bending of the optical functional layer 100. For example, the thickness of the anti-fingerprint layer 4 is 10 nm. In some embodiments, the anti-fingerprint layer 4 is made of perfluoropolyether material.

[0098] As shown in Figure 7. In a second aspect, the present invention provides a method for manufacturing an optical functional layer 100, used in any of the above possible embodiments of the optical functional layer 100, the method comprising:

[0099] S101. A layered adhesive material is arranged on the surface of the light-transmitting base layer 1, and a protrusion 21 is formed by pressing the adhesive material with a mold.

[0100] The above-described manufacturing method enables the simple and rapid fabrication of the optical functional layer 100 provided in the embodiments of the present invention. Specifically, in some embodiments, the manufacturing method involves depositing a layered adhesive material (e.g., UV-curable adhesive or thermoplastic curable adhesive) on the surface of a light-transmitting substrate 1 (e.g., made of any of the materials selected from PET, PC, CPI, or UTG). The layered adhesive material is then positioned facing a mold with recesses, causing the mold to compress the layered adhesive material. Light is then irradiated from the opposite side of the light-transmitting substrate 1 where the layered adhesive material is deposited, causing the adhesive material to cure. Alternatively, the layered adhesive material can be baked to cure it. Finally, the mold is removed. Thus, the manufacturing method forms an anti-glare surface G with a specific shape and size on the adhesive material through a mold-pressing process.

[0101] In some embodiments, the adhesive material is a thermoplastic curable adhesive, such as an acrylic resin solvent. In some embodiments, the viscosity of the acrylic resin solvent before baking is less than 100 cgs to meet the processing requirements of the mold imprinting process.

[0102] In embodiments where the optical functional layer 100 further includes an antireflection layer 3, exemplarily, the antireflection layer 3 is disposed on the side of the antiglare layer 2 facing away from the light-transmitting substrate. In some embodiments, as shown in FIG8, the manufacturing method of the optical functional layer 100 further includes:

[0103] S201. An anti-reflection layer 3 is formed by depositing multiple layers of inorganic materials on the anti-glare surface G in a vacuum environment using vapor deposition or sputtering methods, or by coating the anti-glare surface G with hollow silicon sphere coating material to form the anti-reflection layer 3.

[0104] In an embodiment where the optical functional layer 100 further includes an anti-fingerprint layer 4, exemplarily, the anti-fingerprint layer 4 is disposed on the side of the anti-reflection layer 3 facing away from the anti-fingerprint layer 4. Corresponding to this embodiment, exemplarily, the manufacturing method of the optical functional layer 100 further includes:

[0105] S202, The anti-fingerprint layer 4 is formed by vacuum coating or wet spraying on the side of the anti-reflective layer 3 away from the anti-fingerprint layer 4.

[0106] The above are merely some embodiments and implementations of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An optical functional layer (100) for being arranged on a display screen (1001), characterized in that, The anti-glare layer (2) is arranged on the first surface (11) of the light-transmitting substrate, and the anti-glare layer (2) comprises a plurality of convex portions (21), and the plurality of convex portions (21) collectively form an anti-glare surface (G) away from the surface of the light-transmitting substrate (1). The anti-glare surface (G) is taken as a reference surface (F), and the absolute value of the tangent slope of any position on the anti-glare surface (G) is less than or equal to 0.

1. The absolute value of the slope change rate of any position on the anti-glare surface (G) is less than or equal to 0.

5. The position with the maximum distance between each convex portion (21) and the reference surface (F) is the vertex (T) of the convex portion (21), and the height difference between the vertices of any two convex portions (21) in the plurality of convex portions (21) in the height direction is less than or equal to 1 um, and the height direction is perpendicular to the reference surface (F).

2. The optically functional layer (100) according to claim 1, characterized in that The position with the maximum distance between each convex portion (21) and the reference surface (F) is the vertex (T) of the convex portion (21), and the position with the minimum distance between each convex portion (21) and the reference surface (F) is the bottom point (B) of the convex portion (21), and the distance between the vertex (T) of each convex portion (21) and the bottom point (B) of the convex portion (21) in the height direction is 0.1 um-10 um, and the height direction is perpendicular to the reference surface (F).

3. The optically functional layer (100) according to claim 1 or 2, characterized in that The maximum size of each convex portion (21) in the direction parallel to the reference surface (F) is 5-100 um.

4. The optically functional layer (100) according to any one of claims 1 to 3, characterized in that The light transmittance of the anti-glare layer (2) is greater than or equal to 90%; and / or, 5. The optically functional layer (100) according to any one of claims 1 to 4, characterized in that The haze of the anti-glare layer (2) is less than or equal to 5%.

6. The optically functional layer (100) according to any one of claims 1 to 5, characterized in that The hardness of the anti-glare layer (2) is greater than or equal to 1H; and / or, The tensile modulus of the anti-glare layer (2) is greater than or equal to 5Gpa; and / or, 7. The optically functional layer (100) according to any one of claims 1 to 6, characterized in that The elongation at break of the anti-glare layer (2) is greater than or equal to 3%. The light-transmitting substrate (1) is made of any one of a polyterephthalate material, a polycarbonate material, a transparent polyimide material, or an ultrathin flexible glass material. The anti-glare layer (2) is made of an acrylic resin material or an epoxy resin material.

8. The optically functional layer (100) according to any one of claims 1 to 7, characterized in that The optical functional layer (100) further comprises an anti-fingerprint layer (4) covering the side of the anti-glare layer (3) away from the anti-glare layer.

9. The optically functional layer (100) according to any one of claims 1 to 8, characterized in that The thickness of the anti-fingerprint layer (4) is less than or equal to 50 nm.

10. The optically functional layer (100) according to any one of claims 1 to 9, characterized in that The manufacturing method comprises:

11. The optically functional layer (100) according to claim 10, characterized in that arranging a layered gelatinous material on the surface of the light-transmitting substrate (1), and pressing on the gelatinous material by a mold to form the convex portions (21).

12. The optically functional layer (100) according to claim 10, characterized in that ​ 13. The optically functional layer (100) according to claim 12, characterized in that ​ 14. A method of manufacturing an optical functional layer for manufacturing the optical functional layer (100) according to any one of claims 1-13, characterized in that, ​ ​ 15. A display device (1000), characterized by The display device (1000) comprises a display screen (1001) and an optical functional layer (100) according to any one of claims 1 to 13, which is arranged on the display screen (1001). The display device (1000) comprises a display screen (1001) and an optical functional layer (100) according to any one of claims 1 to 13, which is arranged on the display screen (1001). The display device (1000) comprises a display screen (1001) and an optical functional layer (100) according to any

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