Multi-dimensional gradual change scattering light guide plate, processing method and backlight plate

Abstract

The present application relates to a kind of multi-dimension gradual scattering light guide plate, processing method and backlight plate, and the light guide plate includes substrate layer and scattering function layer.Substrate layer and scattering function layer are closely adhered, and substrate layer and scattering function layer are respectively made of different light-transmitting material composite;Scattering structure is gradually distributed along at least two dimensions on the light guide plate, scattering structure penetrates substrate layer and scattering function layer, scattering structure is misaligned arrangement in adjacent column in plane, and misalignment amount is 1 / 2-2 / 3 of column spacing;Light guide plate includes light inlet end and light outlet end, in the direction of light outlet end towards light inlet end, the distribution density of scattering structure gradually increases, in the direction of substrate layer towards scattering function layer, the size of scattering structure gradually decreases.Scattering structure gradually increases along light inlet end to light outlet end density, gradually decreases along substrate layer to scattering function layer size, and misaligned arrangement in adjacent column spacing in plane, it is favorable to eliminate bright and dark stripe, let light emitting surface brightness distribution be more uniform.

Description

Technical Field

[0001] This invention relates to the technical field of backlight panels, and more particularly to a multi-dimensional gradient scattering light guide plate, its processing method, and the backlight panel itself. Background Technology

[0002] As the core optical component of the backlight module, the light guide plate realizes the conversion of point / line light sources into surface light sources through the conduction and uniform scattering of light. It is widely used in LCD displays, lighting panels and other fields. Light emission uniformity, light utilization rate and structural adaptability are the core indicators for measuring the performance of the light guide plate, and also the main research and optimization directions in the industry.

[0003] To improve the light output performance of light guide plates, various improvement schemes have been developed in the prior art, such as multi-layer structure design, scattering particle doping, and gradient arrangement of scattering structures. However, many technical defects still exist. For example, Japanese Patent JP2012058480A discloses a multi-layer gradient scattering light guide plate. This scheme uses a single light-transmitting material to prepare a multi-layer structure and achieves gradient changes in scattering characteristics by adjusting the concentration of scattering particles in each layer, attempting to solve the problem of brightness attenuation at the edge of the light guide plate. However, this scheme only involves a one-dimensional gradient change in the scattering concentration of a single material, without using materials with different refractive indices for composite design. It cannot utilize the interface refraction effect to enhance the scattering effect, resulting in significant light transmission loss. At the same time, its scattering structure is uniformly aligned, which easily forms periodic bright and dark stripes, limiting the improvement in light output uniformity. Furthermore, the light receiving structure at the light input end of the light guide plate is not optimized, resulting in significant light leakage at the input end and difficulty in improving light utilization.

[0004] Chinese invention patent CN111100333B discloses a PMMA@SiO2 composite light diffusion plate. This solution uses PMMA / PC as the substrate and optimizes the light diffusion effect by doping with SiO2 scattering particles, improving the haze and light transmittance of a single plate. However, this solution is a single-plate particle-doped modified structure without a multi-layer composite gradient scattering structure. It relies solely on the random diffuse reflection of particles to achieve light diffusion, resulting in local scattering saturation or insufficient scattering. Furthermore, it does not perform gradient control of the concentration of scattering particles, nor does it set up a dedicated scattering structure, making it impossible to achieve directional and precise light scattering, resulting in poor light uniformity. In addition, the plate has a uniform thickness design, leading to poor light transmission compatibility between the light input and output ends, and the problem of edge brightness attenuation is not effectively solved.

[0005] In summary, the existing technology has the following shortcomings: First, it only achieves single-dimensional optimization design without coordinating and matching the material's refractive index characteristics, the size / density gradient of the scattering structure, and the substrate layer thickness design, resulting in limited optical control effects; second, the scattering structures are mostly aligned, which easily produces periodic bright and dark stripes and poor light emission uniformity; third, it does not optimize the structure for receiving light at the incident end, resulting in prominent problems of light leakage and excessive scattering; fourth, the interface treatment of the double-layer structure only focuses on the light emission effect and does not solve the dual problems of interlayer bonding force and interface reflection loss. Summary of the Invention

[0006] The first objective of this invention is to provide a multi-dimensional gradient scattering light guide plate, which aims to solve the technical problems of poor light uniformity, easy generation of periodic bright and dark stripes, low light utilization rate, and weak interlayer bonding of the double-layer composite structure in existing light guide plates.

[0007] To solve the above technical problems, a multi-dimensional gradient scattering light guide plate is provided, comprising:

[0008] Substrate layer;

[0009] A scattering functional layer, wherein the substrate layer is tightly bonded to the scattering functional layer, and the substrate layer and the scattering functional layer are respectively made of different light-transmitting materials;

[0010] The light guide plate is provided with scattering structures that are gradually distributed along at least two dimensions. The scattering structures penetrate the substrate layer and the scattering functional layer. The scattering structures are arranged in adjacent columns with a staggered arrangement in the plane, and the staggered amount is 1 / 2 to 2 / 3 of the column spacing. The light guide plate includes a light-incident end and a light-exit end. In the direction from the light-incident end to the light-exit end, the distribution density of the scattering structures gradually increases, and in the direction from the substrate layer to the scattering functional layer, the size of the scattering structures gradually decreases.

[0011] Furthermore, the substrate layer is made of polymethyl methacrylate or polycarbonate, and the scattering functional layer is made of transparent polyamide or polysulfone.

[0012] Furthermore, the refractive index of the substrate layer is greater than that of the scattering functional layer, and the difference in refractive index between the substrate layer and the scattering functional layer is within the range of [0.01, 0.08].

[0013] Further, the thickness of the substrate layer is denoted as D1, and the thickness of the scattering functional layer is denoted as D2, wherein the ratio between D2 and D1 is in the range of [1 / 10, 1 / 3].

[0014] Furthermore, the substrate layer includes a light-incident region disposed near the light-incident end and a light-emitting region disposed near the light-emitting end. In the direction from the light-incident end to the light-emitting end, the thickness of the light-incident region is configured to gradually decrease, while the thickness of the light-emitting region is configured to remain constant.

[0015] Furthermore, the scattering structure is configured in the shape of a frustum, and the scattering structure extends from the substrate layer to the scattering functional layer. The sidewall tilt angle of the scattering structure is adapted to the refractive index difference between the substrate layer and the scattering functional layer, and the thickness gradient slope of the incident light region is inversely linked to the distribution density gradient slope of the scattering structure in the incident light region.

[0016] Furthermore, the bonding surface between the substrate layer and the scattering functional layer is provided with a frosted texture, with a roughness of 0.1-0.3 μm.

[0017] Furthermore, scattering particles are added to the scattering functional layer, and the concentration of scattering particles in the scattering functional layer is inversely matched with the size and density of the scattering structure along the thickness and length directions in a gradient direction.

[0018] A second objective of this invention is to provide a method for processing a light guide plate, for preparing the aforementioned light guide plate, comprising the following steps:

[0019] S1. Prepare a substrate layer melt and a scattering functional layer melt separately. Add scattering particles to the scattering functional layer melt. The amount of scattering particles added is 0.5%-3% of the mass of the scattering functional layer melt. The scattering particles need to undergo surface modification treatment. The modifier is a silane coupling agent. The amount of silane coupling agent added is 1%-2% of the mass of the scattering particles. According to the size gradient requirements of the scattering structure, the concentration of scattering particles added is controlled in different regions of the scattering functional layer melt to achieve a concentration gradient distribution along the thickness direction and the length direction.

[0020] S2. Using a co-extrusion molding process, the melt of the substrate layer and the melt of the scattering functional layer are fed into the two barrels of the co-extruder, and then extruded through a composite die with a frosted texture to form a composite board in which the substrate layer and the scattering functional layer are tightly bonded.

[0021] S3. Preheat the composite board at a temperature of 80-100℃ for 10-20 minutes. Use laser engraving technology to adjust the laser engraving parameters according to the refractive index difference between the substrate layer and the scattering functional layer to process the scattering structure with the corresponding sidewall tilt angle. Process a multi-dimensional gradient scattering structure with adjacent columns staggered on the composite board.

[0022] S4. Cut, grind, and clean the composite material with the scattering structure to remove surface burrs and impurities, and obtain the light guide plate.

[0023] A third objective of this invention is to provide a backlight panel comprising:

[0024] The aforementioned light guide plate;

[0025] A light source is positioned at the light-incident end of the light guide plate;

[0026] A reflective film is attached to the side of the substrate layer opposite to the scattering functional layer.

[0027] Implementing the embodiments of the present invention will have the following beneficial effects:

[0028] In this embodiment, the multi-dimensional gradient scattering light guide plate has the following characteristics: First, the density of the scattering structure gradually increases from the light-incident end to the light-outcident end, and the size gradually decreases from the substrate layer to the scattering functional layer. Furthermore, it is arranged in a staggered manner with adjacent column spacing in the plane. This not only compensates for the brightness attenuation during light transmission but also breaks the periodic scattering pattern caused by the traditional aligned arrangement, which is beneficial for eliminating bright and dark stripes. Combined with the frustum-shaped scattering structure and the matching design of the refractive index difference, it achieves directional and precise scattering of light, making the brightness distribution of the light-outcident surface more uniform.

[0029] Secondly, the substrate layer uses a high refractive index material and the scattering functional layer uses a low refractive index material. The interface refraction effect is used to enhance the scattering effect and reduce the direct light transmission loss. The bonding surface between the substrate layer and the scattering functional layer is set with a 0.1-0.3μm frosted texture, which can reduce interface reflection loss and improve the interlayer bonding force, avoiding optical defects caused by the delamination of the double-layer structure. At the same time, the reverse linkage design of the gradual thickness of the light-incident area and the gradual density of the scattering structure enhances the light-receiving capacity of the light-incident end, which helps to solve the problems of light leakage and excessive scattering at the light-incident end, greatly reduces various losses of light in the transmission and scattering process, improves the overall light utilization rate, and reduces the energy consumption of the backlight module.

[0030] Thirdly, the concentration of scattering particles in the scattering functional layer is matched in reverse gradient with the size and density of the scattering structure along the thickness and length directions, achieving complementary synergy between structural scattering and particle scattering, avoiding the problem of local scattering saturation or insufficient scattering, and making the transmission and scattering process of light in the light guide plate more in line with optical laws, further optimizing the overall light output quality. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a bottom view of the light guide plate described in an embodiment of the present invention;

[0033] Figure 2 This is a front view of the light guide plate described in an embodiment of the present invention;

[0034] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle;

[0035] Figure 4 This is a flowchart of the processing method of the light guide plate according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the backlight panel according to an embodiment of the present invention.

[0037] Wherein: 100, light guide plate; 110, substrate layer; 111, light incident area; 112, light emitting area; 120, scattering functional layer; 130, scattering structure; 140, light incident end; 150, light emitting end; 160, frosted texture;

[0038] 200. Backlight panel; 210. Light source; 220. Reflective film. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0040] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Please refer to Figures 1-3This invention provides a multi-dimensional gradient scattering light guide plate 100, which includes a substrate layer 110 and a scattering functional layer 120. The substrate layer 110 and the scattering functional layer 120 are tightly bonded together, and the substrate layer 110 and the scattering functional layer 120 are respectively made of different light-transmitting materials. The light guide plate 100 is provided with scattering structures 130 that are gradually distributed along at least two dimensions. The scattering structures 130 penetrate the substrate layer 110 and the scattering functional layer 120, and the scattering structures 130 are arranged in adjacent columns with a staggered arrangement in the plane, the staggered amount being 1 / 2 to 2 / 3 of the column spacing. The light guide plate 100 includes a light-incident end 140 and a light-exit end 150. In the direction from the light-incident end 140 to the light-exit end 150, the distribution density of the scattering structures 130 gradually increases, and in the direction from the substrate layer 110 to the scattering functional layer 120, the size of the scattering structures 130 gradually decreases. For example, the staggered amount of adjacent columns of scattering structures 130 is 1 / 2 of the column spacing. After light enters from the light-incident end 140 of the light guide plate 100, it undergoes multiple reflections and scatterings at the interface and within the substrate layer 110 and the scattering functional layer 120. This results in an unavoidable natural brightness attenuation along the light transmission direction from the light-incident end 140 to the light-emitting end 150. If the density of the scattering structure 130 is uniform, the brightness of the light-emitting end 150 will be significantly lower than that of the light-incident end 140, creating a noticeable unevenness where the light-incident end 140 is brighter and the light-emitting end 150 is darker. In this solution, the distribution density of the scattering structure 130 gradually increases from the light-incident end 140 to the light-emitting end 150. With sufficient light at the light-incident end 140, the low-density scattering structure 130 only achieves moderate light scattering, avoiding excessive scattering that would waste brightness. After the light attenuates at the light-emitting end 150, the high-density scattering structure 130 can fully scatter and emit the remaining light, compensating for the brightness attenuation during light transmission and ensuring a balanced brightness of the light emitted from the light guide plate 100 along its length. Traditional light guide plates 100 typically employ row-and-column aligned scattering structures 130. This arrangement causes light to be concentrated and scattered at the same spatial location, resulting in periodic optical interference. Bright spots easily form directly above the scattering structures 130, while dark patterns easily form in the gaps between adjacent structures, ultimately manifesting as a grid-like pattern of bright and dark stripes on the light-emitting surface, severely affecting the uniformity of light output. This solution sets the scattering structures 130 in a staggered arrangement of adjacent columns, allowing the originally aligned scattering structures 130 to be distributed intermittently in the plane. This breaks up the periodicity of light scattering, resulting in irregular and uniform coverage of the scattering positions on the light-emitting surface. The gaps between a column of scattering structures 130 are filled by the scattered light from adjacent staggered columns, fundamentally avoiding the bright and dark stripes caused by periodic scattering and making the light distribution on the light-emitting surface more continuous and uniform.In this design, the size of the scattering structure 130 gradually decreases from the substrate layer 110 to the scattering functional layer 120. The large-size scattering structure 130 on the substrate layer 110 side can fully scatter the light with a wide range and high intensity, breaking the concentrated light into uniform diffuse light. The small-size scattering structure 130 on the scattering functional layer 120 side can precisely scatter and control the light output after the initial scattering, avoiding excessive local scattering caused by the large-size structure in the light output layer. This allows the light to be uniformly scattered and emitted in the thickness direction of the light guide plate 100. Combined with the gradual change in density in the length direction, this helps to achieve uniform light output across the entire plane.

[0043] In this embodiment, the multi-dimensional gradient scattering light guide plate 100 has the following characteristics: First, the density of the scattering structure 130 gradually increases from the light-incident end 140 to the light-emitting end 150, and the size gradually decreases from the substrate layer 110 to the scattering functional layer 120. Furthermore, it is arranged in a staggered manner with adjacent column spacing in the plane, which not only compensates for the brightness attenuation during light transmission but also breaks the periodic scattering pattern caused by the traditional aligned arrangement. This is beneficial for eliminating bright and dark stripes. Combined with the frustum-shaped scattering structure 130 and the adaptation design of the refractive index difference, it achieves directional and precise scattering of light, making the brightness distribution of the light-emitting surface more uniform.

[0044] Secondly, the substrate layer 110 uses a high refractive index material and the scattering functional layer 120 uses a low refractive index material. The interface refraction effect is used to enhance the scattering effect and reduce the direct light transmission loss. The bonding surface of the substrate layer 110 and the scattering functional layer 120 is provided with a 0.1-0.3μm frosted texture 160, which can reduce the interface reflection loss and improve the interlayer bonding force, avoiding optical defects caused by the delamination of the double-layer structure. At the same time, the reverse linkage design of the thickness gradient of the light-incident area 111 and the density gradient of the scattering structure 130 enhances the light-receiving capacity of the light-incident end 140, which helps to solve the problems of light leakage and excessive scattering at the light-incident end 140, greatly reduces various losses of light in the transmission and scattering process, improves the overall light utilization rate, and reduces the energy consumption of the backlight module.

[0045] Thirdly, the concentration of scattering particles in the scattering functional layer 120 is matched in the opposite direction of the thickness and length with the size and density of the scattering structure 130 in a gradient, so as to achieve complementary synergy between structural scattering and particle scattering, avoid the problem of local scattering saturation or insufficient scattering, and make the transmission and scattering process of light in the light guide plate 100 more in line with optical laws, further optimizing the overall light output quality.

[0046] In one possible implementation, the substrate layer 110 is made of polymethyl methacrylate (PMMA) or polycarbonate, and the scattering functional layer 120 is made of transparent polyamide or polysulfone. Exemplarily, in this embodiment, the substrate layer 110 is made of PMMA, and the scattering functional layer 120 is made of transparent polyamide. PMMA has a visible light transmittance of over 92% and a refractive index of 1.49-1.50. Light experiences low reflection loss when propagating within it, and its critical angle for total internal reflection is moderate, effectively enabling long-distance light transmission. Transparent polyamide has a visible light transmittance of approximately 85%-89% and a refractive index of 1.46-1.48.

[0047] In one possible implementation, the refractive index of the substrate layer 110 is greater than that of the scattering functional layer 120, and the difference in refractive index between the substrate layer 110 and the scattering functional layer 120 is within the range of [0.01, 0.08]. For example, the light guide plate 100 of this application is prepared by composite material of two materials with different refractive indices, allowing light to refract upon reaching the interface, changing its propagation direction before incident on the scattering structure 130. This enables the scattering structure 130 to scatter light in all directions, breaking the directional propagation law of light and significantly improving the uniformity of scattering. Simultaneously, the refracted light forms multi-angle contact with the sidewalls of the scattering structure 130, further enhancing the scattering effect and making it easier for light to exit uniformly from the light-emitting surface. If the refractive index difference is less than 0.01, the optical properties of the two layers are nearly identical, the refraction angle of light at the interface is extremely small, and the refraction effect is negligible, making it no different from a homogeneous double-layer structure. Therefore, the design objective of enhancing the scattering effect of the scattering structure 130 through refraction cannot be achieved, and the problems of poor light emission uniformity and weak scattering effect will still exist. If the refractive index difference is greater than 0.08, according to the law of refraction, the angle of refraction of light at the interface will increase significantly, and the critical angle of total internal reflection will decrease significantly. A large amount of light will undergo total internal reflection at the interface and will not be able to enter the scattering functional layer 120. Instead, it will circulate and be conducted within the substrate layer 110, resulting in a decrease in the brightness of the scattering functional layer 120 due to insufficient light. Furthermore, excessive total internal reflection will cause uneven light distribution within the substrate layer 110, forming local bright spots, which will reduce the uniformity of light output. When the refractive index difference is 0.01-0.04, the sidewall tilt angle β of the scattering structure 130 is designed to be 45°-55° to adapt to the direction of light refraction at small angles. The shallow-angle sidewalls achieve gentle, directional scattering of light, avoiding insufficient scattering caused by direct light transmission under small refractive index differences. When the refractive index difference is 0.05-0.08, the sidewall tilt angle β is designed to be 60°-70° to adapt to the direction of light refraction at large angles. The large-angle sidewalls disperse concentrated refracted light, avoiding bright spots caused by localized light concentration under high refractive index differences. The sidewall tilt angle β of the scattering structure 130 is defined as the acute angle formed between the sidewall of the frustum-shaped scattering structure 130 and the bonding surface of the substrate layer 110 / scattering functional layer 120 of the light guide plate 100.

[0048] Please refer to Figure 2In one possible implementation, the thickness of the substrate layer 110 is denoted as D1, and the thickness of the scattering functional layer 120 is denoted as D2, wherein the ratio of D2 / D1 is in the range of [1 / 10, 1 / 3]. For example, in this embodiment, D2 / D1 is 0.3. Of course, in specific applications, D2 / D1 can also be 0.1, 0.15, 0.2, or 0.25. The substrate layer 110 serves as the main support and light transmission layer, with a thickness of 0.5-3 mm. The scattering functional layer 120 is a light-scattering layer, with a thickness of 0.1-0.5 mm. This ratio ensures that the substrate layer 110 sufficiently supports the through-type scattering structure 130, while reserving space for the scattering functional layer 120. In terms of connection, the two layers are tightly bonded through co-extrusion molding, and the bonding surface has a 0.1-0.3 μm frosted texture 160. This ratio ensures uniform bonding force and stronger adhesion. For small display scenarios such as mobile phones and smart wearable devices, and for large display scenarios such as monitors and lighting panels, the ratio of D2 / D1 should be between 1 / 10 and 1 / 5, and the ratio of D2 / D1 should be between 1 / 5 and 1 / 3. Controlling the thickness ratio of the substrate layer 110 to the scattering functional layer 120 helps ensure the gradual and continuous change in the size of the scattering structure 130, adapts to the interface effect of refractive index difference, and reduces light loss.

[0049] Please refer to Figure 2In one possible implementation, the substrate layer 110 includes a light-incident region 111 located near the light-incident end 140 and a light-emitting region 112 located near the light-emitting end 150. In the direction from the light-incident end 140 to the light-emitting end 150, the thickness of the light-incident region 111 is configured to gradually decrease, while the thickness of the light-emitting region 112 is configured to remain constant. Exemplarily, the substrate layer 110 is divided into a light-incident region 111 and a light-emitting region 112. Positionally, the light-incident region 111 directly corresponds to the light source 210, and the light-emitting region 112 covers the light-emitting range of the main body of the light guide plate 100, with the two seamlessly connected. The thickness of the light-incident region 111 smoothly decreases from the light-incident end 140 to the light-emitting end 150 at a slope of 0.0-0.02 mm / mm, with a thickness increase of 0.1-0.2 mm. The thickened portion is located on the side of the substrate layer 110 away from the scattering functional layer 120. The thickness of the light-emitting region 112 remains constant, and it smoothly transitions from the light-incident region 111 without any steps. The angle α between the inclined surface of the gradually thickening region of the light-incident area 111 and the horizontal plane is set to 1.5°~3°. In this embodiment, the angle α is specifically set to 2°, which is the optimal implementation value. The light-incident area 111 and the light-emitting area 112 are an integrated structure, formed in one step by co-extrusion molding, with a continuous and unbroken thickness gradient. This enhances the light-receiving capacity of the light-incident end 140 and reduces light leakage; it is inversely linked to the density of the scattering structure 130 to avoid excessive scattering; it adapts to the refractive index difference and the gradual design of the scattering structure 130 to improve the uniformity of light emission; it ensures the overall structural stability of the light guide plate 100 and is suitable for large-scale processing. The light-incident end 140 is the area where light is concentrated. The thickness of the light-incident area 111 increases and then smoothly thins towards the light-emitting end 150, which is equivalent to forming a light buffer zone at the light-incident end 140. This structure increases the light contact area at the light-incident end 140, making it easier for the divergent light emitted by the light source 210 to be captured by the substrate layer 110, reducing light leakage from the edge of the light-incident end 140. Simultaneously, the thickened substrate layer 110 extends the light transmission path at the light-incident end 140, reducing the probability of light directly penetrating the bottom surface of the substrate layer 110 and improving light utilization. As light travels from the light-incident end 140 to the light-emitting end 150, it naturally attenuates. If the substrate layer 110 has a uniform thickness, the light at the light-incident end 140 may be sufficient, but the low density of the scattering structure 130 could easily lead to localized bright spots due to light concentration. Even after light attenuation, the high density of the scattering structure 130 at the light-emitting end 150 may still result in insufficient brightness. The gradually decreasing thickness of the light-incident region 111, combined with the reverse gradual change in density of the scattering structure 130, allows the thick substrate and low-density scattering in the thickened area of ​​the light-incident end 140 to complement the thin substrate and high-density scattering in the light-emitting end 150, compensating for the brightness attenuation during light transmission and resulting in more balanced brightness across the entire board surface.The thickness of the light-incident region 111 is smoothly and gradually changes without steps, avoiding abrupt changes in the direction of light refraction caused by abrupt structural changes, and making the total internal reflection of light in the substrate layer 110 smoother. At the same time, the thickened part is located on the side of the substrate layer 110 away from the scattering functional layer 120, which does not affect the flatness of the scattering functional layer 120, ensuring that the interface reflection loss is minimized when light is refracted from the substrate layer 110 into the scattering functional layer 120, and further ensuring the light output effect.

[0050] Please refer to Figure 2 and Figure 3In one possible implementation, the scattering structure 130 is configured in the shape of a frustum, and extends from the substrate layer 110 to the scattering functional layer 120. The sidewall tilt angle β of the scattering structure 130 is adapted to the refractive index difference between the substrate layer 110 and the scattering functional layer 120, and the thickness gradient slope of the incident light region 111 is inversely linked to the distribution density gradient slope of the scattering structure 130 in the incident light region 111. Exemplarily, in this embodiment, the scattering structure 130 is frustum-shaped, forming an integrated structure that penetrates the substrate layer 110 and the scattering functional layer 120. The substrate layer 110 side is the lower base of the frustum, and the scattering functional layer 120 side is the upper base of the frustum, forming a seamless connection with the double-layer structure. The overall structure is adapted to the thickness direction of the light guide plate 100. The sidewall tilt angle β of the scattering structure 130 is precisely matched with the refractive index difference between the substrate layer 110 and the scattering functional layer 120. Specifically, when the refractive index difference between the substrate layer 110 and the scattering functional layer 120 is 0.01-0.04, the sidewall tilt angle β of the scattering structure 130 is matched to 45°-55°; when the refractive index difference is 0.05-0.08, the sidewall tilt angle β of the scattering structure 130 is matched to 60°-70°. By adjusting the tilt angle with the gradient of the refractive index difference, the light refraction direction and the scattering direction of the scattering structure 130 are precisely matched. The thickness gradient slope of the light-incident region 111 and the distribution density gradient slope of the scattering structure 130 are designed to be inversely linked. Specifically, the thickness of the light-incident region 111 decreases smoothly from the light-incident end 140 to the light-exit end 150 at a slope of 0.01-0.02 mm / mm, while the distribution density of the scattering structure 130 in the light-incident region 111 increases smoothly at a slope of 40-60 structures / cm²·mm. Furthermore, a 0.1 mm increase in the thickness of the substrate layer 110 in the light-incident region 111 corresponds to a scattering structure 130 density of ≤120 structures / cm², and a 0.2 mm increase corresponds to a scattering structure 130 density of ≤100 structures / cm², forming an inverse matching relationship where the thicker the layer, the lower the density, and the thinner the layer, the higher the density. The design that adapts the tilt angle and refractive index difference allows the refracted light at the interface to fully contact the sidewall of the scattering structure 130, enhancing the synergistic optical effect of refraction and scattering, and improving the uniformity and utilization of light scattering. The reverse linkage of thickness and density slope precisely matches the light transmission characteristics of the light-incident end 140, avoiding the problem of excessive light scattering in the thick area and insufficient scattering in the thin area of ​​the light-incident end 140, effectively compensating for the brightness attenuation of light transmission, while ensuring the balance between light reception and scattering in the light-incident area 111, further improving the uniformity of light output across the entire surface of the light guide plate 100.

[0051] Please refer to Figure 2 and Figure 3In one possible implementation, the bonding surfaces of the substrate layer 110 and the scattering functional layer 120 are provided with a frosted texture 160, with a roughness of 0.1-0.3 μm. Exemplarily, in this embodiment, the side of the substrate layer 110 facing the scattering functional layer 120 and the side of the scattering functional layer 120 facing the substrate layer 110 are bonded together, and both bonding surfaces are provided with a frosted texture 160. The texture is an irregular micro-convex-concave structure, and the frosted textures 160 on both sides match each other. The overall roughness is precisely controlled within the range of 0.1-0.3 μm. This is achieved through a co-extrusion molding process, simultaneously forming the double-layer composite structure without the need for subsequent secondary processing. The roughness of the frosted texture 160 significantly improves the interlayer bonding between the substrate layer 110 and the scattering functional layer 120, effectively avoiding delamination and peeling problems in the processing and use of the double-layer composite structure, and ensuring structural stability. At the same time, it weakens the specular reflection at the interface between the two layers, reduces the reflection loss of light at the interface, allows more light to participate in refraction and scattering, and improves the overall light utilization rate. Moreover, the frosted texture 160 does not affect the flatness of the light-emitting surface of the scattering functional layer 120, and will not cause optical interference to the final light emission effect. It works synergistically with the design of refractive index difference adaptation and scattering structure 130 gradient to further optimize the light emission uniformity of the light guide plate 100.

[0052] In one possible implementation, scattering particles (not shown in the figure) are added to the scattering functional layer 120. The concentration of scattering particles in the scattering functional layer 120 is inversely matched to the size and density of the scattering structure 130 along the thickness and length directions. Exemplarily, the scattering particles added in this invention are silicon dioxide or titanium dioxide. The particles are surface-modified with a silane coupling agent, are regularly spherical, have a particle size of 0.1-1 μm, and are added at 3% of the melt mass of the scattering functional layer 120. They are uniformly dispersed inside the scattering functional layer 120, forming a dual scattering system with the frustum-shaped scattering structure 130. The coupling agent is an alkoxysilane-based coupling agent suitable for use with inorganic scattering particles such as silica and titanium dioxide and transparent polymer light-transmitting materials such as polyamide and polysulfone. Preferably, it is an aminosilane coupling agent or an epoxysilane coupling agent. Specifically, one or more of γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), and γ-aminopropyltrimethoxysilane (KH540) can be used in combination. The thickness direction refers to the direction perpendicular to the light guide plate 100, i.e., the direction of extension from the substrate layer 110 to the scattering functional layer 120. The length direction refers to the direction of extension along the plane of the light guide plate 100, i.e., the horizontal transmission direction from the light-incident end 140 to the light-exit end 150. The size of the scattering structure 130 gradually changes from 30-50 μm to 2-5 μm, corresponding to an inverse gradient distribution of the scattered particle concentration. Specifically, at the junction of the substrate layer 110 and the scattering functional layer 120, corresponding to a diameter of 30-50 μm for the scattering structure 130, the mass percentage of scattered particles is 2.5%-3%; in the middle of the scattering functional layer 120, corresponding to a diameter of 15-25 μm for the scattering structure 130, the mass percentage of scattered particles is 1.5%-2%; and on the light-emitting side of the scattering functional layer 120, corresponding to a size of 2-5 μm for the scattering structure 130, the mass percentage of scattered particles is 0.5%-1%. In other words, the larger the size of the scattering structure 130, the stronger the scattering ability and the lower the particle concentration; conversely, the smaller the structure size, the weaker the scattering ability and the higher the particle concentration, achieving complementary scattering effects. The density of scattering structure 130 gradually changes from 100-200 particles / cm² to 500-800 particles / cm², corresponding to an inverse gradient distribution of scattered particle concentration. Specifically, the numerical matching is as follows: at the light-incident end (140) of the light guide plate 100, the density of scattering structure 130 is 100-200 particles / cm², with a scattered particle mass percentage of 2%-2.5%; in the central region of the light guide plate 100, the density of scattering structure 130 is 300-400 particles / cm², with a scattered particle mass percentage of 1%-1.5%; and at the light-exit end (150) of the light guide plate 100, the density of scattering structure 130 is 500-800 particles / cm², with a scattered particle mass percentage of 0.5%-1%. Higher density of scattering structure 130 results in more complete scattering and lower particle concentration; conversely, lower density results in weaker scattering and higher particle concentration, thus avoiding localized scattering saturation or insufficiency.The particle size of the scattering particles is synchronously gradient-matched with the size of the scattering structure 130, forming a dual synergy with the concentration gradient. Specifically, when the size of the scattering structure 130 is ≥20μm, it is matched with 0.8-1μm spherical scattering particles; when the size of the scattering structure 130 is <20μm, it is matched with 0.1-0.5μm spherical scattering particles.

[0053] Please refer to Figure 4 The second objective of this invention is to provide a method for processing a light guide plate 100, which includes the following steps:

[0054] S1. Prepare a substrate layer 110 melt and a scattering functional layer 120 melt separately. Add scattering particles to the scattering functional layer 120 melt. The amount of scattering particles added is 0.5%-3% of the mass of the scattering functional layer 120 melt. The scattering particles need to undergo surface modification treatment. The modifier is a silane coupling agent. The amount of silane coupling agent added is 1%-2% of the mass of the scattering particles. According to the size gradient requirements of the scattering structure 130, adjust the concentration of scattering particles in different regions of the scattering functional layer 120 melt to achieve a concentration gradient distribution along the thickness direction and the length direction.

[0055] S2. Using a co-extrusion molding process, the melt of the substrate layer 110 and the melt of the scattering functional layer 120 are fed into the two barrels of the co-extruder, and then extruded through a composite die with a frosted texture 160 to form a composite board in which the substrate layer 110 and the scattering functional layer 120 are tightly bonded.

[0056] S3. Preheat the composite board at a temperature of 80-100℃ for 10-20 minutes. Use laser engraving technology to adjust the laser engraving parameters according to the refractive index difference between the substrate layer 110 and the scattering functional layer 120 to process a scattering structure 130 with a corresponding sidewall tilt angle β. Process a multi-dimensional gradient scattering structure 130 with adjacent columns staggered on the composite board.

[0057] S4. Cut, grind, and clean the composite board with the processed scattering structure 130 to remove surface burrs and impurities, and obtain the light guide plate 100.

[0058] Please refer to Figure 5A third objective of this invention is to provide a backlight panel 200, comprising the aforementioned light guide plate 100, light source 210, and reflective film 220. The light source 210 is disposed at the light-incident end 140 of the light guide plate 100; the reflective film 220 is adhered to the side of the substrate layer 110 facing away from the scattering functional layer 120. Exemplarily, the light source 210 is fixedly disposed on the end face of the light-incident end 140 of the light guide plate 100, forming a seamless optical connection with the light-incident end 140. The emitting surface of the light source 210 completely covers the effective end face of the light-incident end 140 of the light guide plate 100, and the light is incident perpendicularly onto the light-incident area 111 of the light guide plate 100. The reflective film 220 is integrally adhered to the surface of the substrate layer 110 of the light guide plate 100 facing away from the scattering functional layer 120, forming a tight, gapless fit with the substrate layer 110. The coverage area of ​​the reflective film 220 is completely consistent with the effective surface area of ​​the light guide plate 100, without any missing areas or edge lifting issues. The light source 210 is an array of LED point light sources 210, and the reflective film 220 is a high-reflectivity optical reflective film 220, which is a double-layer structure of PET substrate composite high-reflectivity coating.

[0059] Example 1:

[0060] Step 1: Preparation of substrate layer 110 melt and scattering functional layer 120 melt

[0061] Optical-grade polymethyl methacrylate (PMMA) particles were selected and fed into a single-screw extruder. The barrel temperatures were set to 200℃ in zone one, 210℃ in zone two, and 220℃ in zone three, with a screw speed of 150 r / min. After melting and plasticizing, a uniform PMMA substrate layer 110 melt was obtained, and the melt temperature was stabilized at 215℃. Spherical titanium dioxide scattering particles with a particle size of 0.5 μm were selected, and γ-aminopropyltriethoxysilane (KH550) silane coupling agent was added at 1.5% of the scattering particle mass. Deionized water was added to prepare a 5% (w / w) modification solution. The solution was stirred in a constant temperature water bath at 30℃ for 60 min, and then dried in an oven at 80℃ for 2 h to obtain surface-modified titanium dioxide scattering particles. Transparent polyamide optical-grade particles were selected and fed into another single-screw extruder. The barrel temperature was set to 190°C in zone one, 200°C in zone two, and 210°C in zone three, with a screw speed of 120 r / min. After melting and plasticizing, a transparent polyamide melt was obtained. Modified titanium dioxide scattering particles were added at 2% of the mass of the scattering functional layer 120 melt. The melt was stirred at high speed in a melt mixer at a speed of 800 r / min to achieve uniform dispersion. At the same time, a particle concentration gradient distribution with a thickness direction of 2.8% to 0.8% and a length direction of 2.2% to 0.8% was formed in the melt through a melt stratification control device, resulting in the scattering functional layer 120 melt. The melt temperature was stabilized at 205°C.

[0062] Step 2: Co-extrude composite sheet

[0063] The prepared PMMA substrate layer 110 melt and transparent polyamide scattering functional layer 120 melt were fed into the two barrels of a co-extruder, respectively. The barrel temperature was kept consistent with the melt temperature. The extrusion flow rate of the substrate layer 110 melt was 30 kg / h, and the extrusion flow rate of the scattering functional layer 120 melt was 6 kg / h, ensuring D2 / D1 = 1 / 5. After passing through the co-extruder core, the melt entered a composite die with a frosted texture 160. The die temperature was 210℃, the die lip gap was 1.2 mm, and the roughness of the frosted texture 160 roller inside the die was 0.2 μm. After composite extrusion through the die, the material was drawn and shaped by a 25℃ cooling roller to obtain a composite sheet with a 1.0 mm thick substrate layer 110 and a 0.2 mm thick scattering functional layer 120 tightly bonded together. The flatness error of the sheet was ≤0.02 mm.

[0064] Step 3: Preheating and laser engraving of the scattering structure 130

[0065] The composite board was cut into 160mm×80mm pieces and placed in a constant temperature preheating oven. The preheating temperature was set to 90℃ and the preheating time to 15 minutes to ensure uniform heating of the board and prevent local warping. A fiber laser engraving machine was selected. Based on the refractive index difference of 0.02 between the substrate layer 110 (1.495) and the scattering functional layer 120 (1.475), the laser power was set to 10W, the engraving speed to 200mm / s, the engraving focal length to 15mm, and the processing depth to 1.2mm. Import the scattering structure 130 processing drawing into the laser engraving machine, and design the arrangement with the adjacent columns staggered by 1 / 2 of the column spacing. The density of the scattering structure 130 at the light-incident end 140 is 150 / cm², and the density at the light-emitting end 150 is 600 / cm². The density increases linearly from the light-incident end 140 to the light-emitting end 150. The scattering structure 130 is frustum-shaped, with a bottom diameter of 40μm on the side of the substrate layer 110 and a top diameter of 3μm on the side of the scattering functional layer 120. The sidewall tilt angle β is 50°. The engraving of all multi-dimensional gradient scattering structures 130 is completed.

[0066] Step 4: Cutting, sanding and cleaning

[0067] A precision cutting machine is used to cut the engraved board to the designed size of 150mm × 70mm. The cutting blade rotates at 3000 rpm and the feed speed is 5mm / s to ensure that the cut edges are free of burrs and chips. The cut edges of the board are lightly sanded with 800-grit wet sandpaper, followed by fine sanding with 2000-grit wet sandpaper to ensure that the edges are smooth and free of scratches. The sanded light guide plate 100 is placed in an ultrasonic cleaner with anhydrous ethanol as the cleaning solution. The cleaning power is set to 100W and the cleaning time is 10 minutes to remove surface dust, burrs, and other impurities. The light guide plate 100 is then removed and dried in a 60℃ hot air oven for 5 minutes to obtain the finished multi-dimensional gradient scattering light guide plate 100.

[0068] Comparative Example 1:

[0069] Step 1: Preparation of substrate layer 110 melt and scattering functional layer 120 melt

[0070] Optical-grade PMMA particles, the same as in the examples, were fed into a single-screw extruder. The barrel temperatures were set at 200°C in zone one, 210°C in zone two, and 220°C in zone three, with a screw speed of 150 r / min. The PMMA melt was obtained at a melt temperature of 215°C. Spherical titanium dioxide particles, the same as in the examples, with a particle size of 0.5 μm, were used directly without silane coupling agent surface modification. Transparent polyamide optical-grade particles, the same as in the examples, were used in a single-screw extruder. The temperatures were set at 190°C in zone one, 200°C in zone two, and 210°C in zone three, with a screw speed of 120 r / min. After melt plasticization, unmodified titanium dioxide particles were uniformly added at a mass ratio of 2%, without concentration gradient control. The stirring speed was 800 r / min, resulting in a scattering functional layer 120 melt with a uniform particle distribution and a melt temperature of 205°C.

[0071] Step 2: Co-extrude composite sheet

[0072] Consistent with the previous example, the PMMA substrate layer 110 melt and the transparent polyamide scattering functional layer 120 melt were fed into a co-extruder with dual barrels at extrusion flow rates of 30 kg / h and 6 kg / h, respectively, ensuring a substrate layer 110 thickness of 1.0 mm and a scattering functional layer 120 thickness of 0.2 mm, with D2 / D1 = 1 / 5. The melt was extruded through a standard smooth composite die (designed without a frosted texture, 160), at a die temperature of 210°C and a lip gap of 1.2 mm. The mixture was then traction-formed using a 25°C cooling roller to obtain a double-layer composite sheet without interface frosting treatment.

[0073] Step 3: Preheating and laser engraving of the scattering structure 130

[0074] Consistent with the previous example, the sheet material was cut to 160mm × 80mm and preheated in a constant-temperature preheating oven at 90℃ for 15 minutes. The same fiber laser engraving machine as in the previous example was used, ignoring refractive index difference adaptation, and directly set to a fixed laser power of 10W, engraving speed of 200mm / s, focal length of 15mm, and processing depth of 1.2mm. Cylindrical scattering structures 130 of uniform size were engraved, without frustum-shaped design or size gradients, with a uniform diameter of 20μm; staggered arrangement was eliminated, and conventional row and column alignment was adopted; there was no density gradient, and the density of the scattering structures 130 across the entire board surface was uniformly 375 structures / cm²; there was no sidewall tilt angle β design, and the sidewalls were straight walls perpendicular to the bonding surface.

[0075] Step 4: Cutting, sanding and cleaning

[0076] The operation was exactly the same as in the example, with precision cutting to 150mm×70mm, edge sanding with 800 grit and 2000 grit wet sandpaper, ultrasonic cleaning with anhydrous ethanol, and drying in a 60℃ hot air oven for 5 minutes to obtain the comparative light guide plate 100 finished product.

[0077] Table 1. Comparison of Core Design and Performance Indicators between Example 1 and Comparative Example 1

[0078]

[0079] This invention solves the problem of particle agglomeration by modifying scattering particles with silane coupling agents and matching concentration gradients, thus avoiding local optical defects. At the same time, it achieves complementary scattering between the structure and the particles, significantly improving the uniformity of light output. In contrast, unmodified particles in the comparative proportion are prone to agglomeration, and uniform distribution can easily lead to local scattering saturation / insufficiency.

[0080] The frosted texture 160 on the bonding surface is key to improving interlayer bonding strength. The interlayer bonding strength of the embodiment is 3 times that of the comparative example, effectively avoiding delamination problems during processing / use, while reducing interface reflection loss; the bonding strength of the smooth bonding surface in the comparative example is weak, and the mirror reflection of the interface leads to a significant decrease in light utilization.

[0081] The multi-dimensional collaborative design of the frustum-shaped scattering structure 130, staggered arrangement, density / size gradient, and sidewall tilt angle β adaptation fundamentally eliminates the periodic bright and dark stripes of conventional aligned arrangements, compensates for the brightness attenuation during light transmission, and achieves precise directional scattering. In contrast, the cylindrical straight-wall structure with a fixed proportional size and uniform density cannot adapt to the light transmission law, resulting in severe light leakage and bright and dark stripes. Overall, the light guide plate 100 produced by the processing method of this invention is far superior to existing conventional processes in terms of core indicators such as light emission uniformity, light utilization rate, and structural stability, solving the key defects of existing technologies.

[0082] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A multi-dimensional gradient scattering light guide plate, characterized in that, include: Substrate layer; A scattering functional layer, wherein the substrate layer is tightly bonded to the scattering functional layer, and the substrate layer and the scattering functional layer are respectively made of different light-transmitting materials; The light guide plate is provided with scattering structures that are gradually distributed along at least two dimensions. The scattering structures penetrate the substrate layer and the scattering functional layer. The scattering structures are arranged in adjacent columns with a staggered arrangement in the plane, and the staggered amount is 1 / 2 to 2 / 3 of the column spacing. The light guide plate includes a light-incident end and a light-exit end. In the direction from the light-incident end to the light-exit end, the distribution density of the scattering structures gradually increases, and in the direction from the substrate layer to the scattering functional layer, the size of the scattering structures gradually decreases.

2. The multi-dimensional gradient scattering light guide plate according to claim 1, characterized in that, The substrate layer is made of polymethyl methacrylate or polycarbonate, and the scattering functional layer is made of transparent polyamide or polysulfone.

3. The multi-dimensional gradient scattering light guide plate according to claim 2, characterized in that, The refractive index of the substrate layer is greater than that of the scattering functional layer, and the difference in refractive index between the substrate layer and the scattering functional layer is within the range of [0.01, 0.08].

4. The multi-dimensional gradient scattering light guide plate according to claim 1, characterized in that, The thickness of the substrate layer is denoted as D1, and the thickness of the scattering functional layer is denoted as D2, wherein the ratio between D2 and D1 is in the range of [1 / 10, 1 / 3].

5. The multi-dimensional gradient scattering light guide plate according to claim 1, characterized in that, The substrate layer includes a light-incident region disposed near the light-incident end and a light-exiting region disposed near the light-exiting end. In the direction from the light-incident end to the light-exiting end, the thickness of the light-incident region is configured to gradually decrease, while the thickness of the light-exiting region is configured to remain constant.

6. The multi-dimensional gradient scattering light guide plate according to claim 5, characterized in that, The scattering structure is configured in the shape of a frustum, and the scattering structure extends from the substrate layer to the scattering functional layer. The sidewall tilt angle of the scattering structure is adapted to the difference in refractive index between the substrate layer and the scattering functional layer, and the thickness gradient slope of the incident light region is inversely linked to the distribution density gradient slope of the scattering structure in the incident light region.

7. The multi-dimensional gradient scattering light guide plate according to claim 1, characterized in that, The bonding surface between the substrate layer and the scattering functional layer is provided with a frosted texture, and the roughness is 0.1-0.3μm.

8. The multi-dimensional gradient scattering light guide plate according to claim 1, characterized in that, The scattering functional layer contains scattering particles, and the concentration of scattering particles in the scattering functional layer is inversely matched to the size and density of the scattering structure along the thickness and length directions in a gradient direction.

9. A method for processing a light guide plate, used to prepare the light guide plate according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Prepare a substrate layer melt and a scattering functional layer melt separately. Add scattering particles to the scattering functional layer melt. The amount of scattering particles added is 0.5%-3% of the mass of the scattering functional layer melt. The scattering particles need to undergo surface modification treatment. The modifier is a silane coupling agent. The amount of silane coupling agent added is 1%-2% of the mass of the scattering particles. According to the size gradient requirements of the scattering structure, the concentration of scattering particles added is controlled in different regions of the scattering functional layer melt to achieve a concentration gradient distribution along the thickness direction and the length direction. S2. Using a co-extrusion molding process, the melt of the substrate layer and the melt of the scattering functional layer are fed into the two barrels of the co-extruder, and then extruded through a composite die with a frosted texture to form a composite board in which the substrate layer and the scattering functional layer are tightly bonded. S3. Preheat the composite board at a temperature of 80-100℃ for 10-20 minutes. Use laser engraving technology to adjust the laser engraving parameters according to the refractive index difference between the substrate layer and the scattering functional layer to process the scattering structure with the corresponding sidewall tilt angle. Process a multi-dimensional gradient scattering structure with adjacent columns staggered on the composite board. S4. Cut, grind, and clean the composite material with the scattering structure to remove surface burrs and impurities, and obtain the light guide plate.

10. A backlight panel, characterized in that, include: The light guide plate according to any one of claims 1-8; A light source is positioned at the light-incident end of the light guide plate; A reflective film is attached to the side of the substrate layer opposite to the scattering functional layer.

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