Composite brightness enhancement film

Abstract

The application relates to a composite brightness enhancement film, comprising a microlens structure layer and a prism structure layer. The prism structure layer is located above the prism structure layer. The microlens structure layer comprises a plurality of convex lens structures, which are composed of a hemispherical lens upper structure and a polygonal bottom, and the bottom is connected with at least one adjacent bottom, so that the light regulation efficiency and the structural stability can be improved. The hemispherical lens upper structure can secondarily converge and diffuse light, so that the brightness and uniformity are improved; the polygonal bottom design can disperse stress and improve wear resistance. The convex lens structure can be combined with different sizes of hemispherical lens upper structures, and the diameter, height and quantity ratio of the hemispherical lens upper structures have a specific range, so as to optimize the optical performance. The extension direction of the convex lens structure and the extension direction of the prism are cross-laid, and the different sizes of hemispherical lens upper structures are randomly arranged, so that the light regulation efficiency and the optical performance can be improved.

Description

Technical Field

[0001] This application relates to the field of optical film technology, and more particularly to a composite brightness enhancement film. Background Technology

[0002] In the field of display technology, the demands for image quality and performance of display devices continue to rise. As a component that enhances display effects, the optimization of brightness enhancement films remains a core issue. Brightness enhancement films enhance the brightness, contrast, and color saturation of display panels by regulating the path and distribution of light, thereby delivering a clearer visual experience. Currently, MOP (Modular Optical Part) lamination films have become the mainstream lamination film product in the market. They typically employ a double-layer structure design. The lower layer is a prism structure layer, constructed from multiple prism arrays in a single direction. This structural design can regulate the direction of light propagation, enabling efficient and uniform light distribution and improving light utilization. The upper layer uses a randomly or regularly arranged microlens structure to further regulate and optimize light. Simultaneously, the clever use of a back coating effectively improves the uniformity of light output, avoiding overly bright or dark areas, thus enhancing the overall quality of the displayed image.

[0003] Currently, MOP composite films are widely used in various display devices, such as LCD TVs, computer monitors, tablets, and smartphones. However, with the large-scale promotion and application of MOP composite films, some problems have gradually emerged. On the one hand, friction or adsorption can easily occur between the upper structure of the MOP and the polarizer of the TV, resulting in white spot defects, affecting the appearance quality of the product, reducing its aesthetic appeal, and leading to higher market demands for the energy-saving performance of TVs. The improvement in energy-saving performance indirectly poses more stringent challenges to the brightness, wear resistance, and anti-adsorption performance of MOP products. Currently, MOP products on the market generally suffer from low brightness, making it difficult to meet the demand for high-brightness products under energy-saving requirements. Furthermore, its wear resistance and anti-adsorption performance need further improvement to ensure stable performance during long-term use.

[0004] Therefore, how to develop a composite brightening film with high brightness, good wear resistance and anti-adsorption properties based on existing MOP lamination film technology through further optimization of design and materials has become one of the technical problems to be solved. Utility Model Content

[0005] The purpose of this application is to provide a high-brightness, high-wear-resistant composite brightness enhancement film, which can effectively improve brightness, enhance the optical performance of the backlight module, and simultaneously reduce the contact area with the television polarizer, thereby effectively improving wear resistance. This objective is achieved through the following technical solution: the composite brightness enhancement film of this application includes a microlens structure layer and a prism structure layer;

[0006] The microlens structure layer is located above the prism structure layer;

[0007] The microlens structure layer includes multiple convex lens structures, each of which includes a hemispherical upper lens structure and a polygonal bottom shape.

[0008] In this configuration, the bottom of each convex lens structure is connected to the bottom of at least one adjacent convex lens structure.

[0009] In one embodiment, the convex lens structure includes two sizes of hemispherical lens upper structures, wherein the diameter of the larger hemispherical lens upper structure is in the range of 30μm-80μm, and the diameter of the smaller hemispherical lens upper structure is in the range of 20μm-60μm.

[0010] In one embodiment, the height of the upper structure of the large-sized hemispherical lens is in the range of 12μm-32μm, and the height of the upper structure of the small-sized hemispherical lens is in the range of 8μm-24μm.

[0011] In one embodiment, the ratio of the number of large-sized hemispherical lens upper structures to small-sized hemispherical lens upper structures is in the range of 1:6 to 1:30.

[0012] In one embodiment, the convex lens structure includes three sizes of hemispherical lens upper structures, wherein the diameter of the large-sized hemispherical lens upper structure is in the range of 40μm-100μm, the diameter of the medium-sized hemispherical lens upper structure is in the range of 30μm-80μm, and the diameter of the small-sized hemispherical lens upper structure is in the range of 20μm-60μm.

[0013] In one embodiment, the polygonal base shape is hexagonal or pentagonal.

[0014] In one embodiment, the extension direction of the convex lens structure intersects with the extension direction of the prism.

[0015] In one embodiment, the upper structures of hemispherical lenses of different sizes are randomly arranged.

[0016] In one embodiment, a low-haze back coating is also included, which is formed on the prism structure layer on the side opposite to the microlens structure layer.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] In the microlens structure layer of this application, the convex lens structure may include two or three hemispherical lens upper structures of different sizes. The convex lens structures of different sizes can more comprehensively collect and converge light rays incident at different angles, allowing for more effective control of light rays as they pass through the microlens structure layer. The reasonable height design allows the convex lens structures of different sizes to work together better, improving the anti-adhesion performance of the composite brightness enhancement film.

[0019] The bottom of the convex lens structure adopts a polygonal shape such as hexagon or pentagon, and the bottom of each convex lens structure is connected to the bottom of at least one adjacent convex lens structure, resulting in a more compact arrangement of the microlens structure layers. The extending direction of the convex lens structures intersects with the extending direction of the prisms, allowing light to be more comprehensively controlled and converged from different directions as it passes through the microlens structure layers and prism structure layers. This reduces light reflection and scattering during propagation, improves light utilization, and thus significantly enhances brightness.

[0020] The upper structure of hemispherical lenses of different sizes is randomly arranged to avoid interference and diffraction phenomena caused by the regular arrangement of the structure during light propagation. This allows light to pass through the microlens structure layer more evenly, improving the uniformity of brightness and further enhancing the optical performance of the backlight module. Attached Figure Description

[0021] Fig. 1 This is a schematic diagram of the structure of the composite brightness enhancement film according to an embodiment of this application;

[0022] Fig. 2 This is a schematic diagram of the microlens structure layer in the composite brightness enhancement film of this application embodiment;

[0023] Fig. 3 This is a schematic diagram of the arrangement of the composite brightness enhancement film convex lens structure in one embodiment of this application;

[0024] Fig. 4 This is a schematic diagram of the arrangement of the composite brightness enhancement film convex lens structure in another embodiment of this application.

[0025] Explanation of reference numerals in the attached figures: 100, prism structure layer; 200, microlens structure layer; 210, convex lens structure; 300, low haze back coating. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0027] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] Brightness enhancement films, by regulating the propagation path and distribution of light, can enhance the brightness, contrast, and color saturation of display panels. However, with the continuous expansion of the market and the ongoing upgrading of demands, MOP (Modular Optical Film) lamination films have gradually revealed some problems during large-scale applications, such as white spots caused by friction with television polarizers and insufficient brightness to meet energy-saving requirements. To overcome these problems and meet the market demand for high-brightness, high-wear-resistance composite brightness enhancement films, this application provides a composite brightness enhancement film solution that, based on the advantages of existing brightness enhancement film technologies, achieves improved brightness, enhanced wear resistance, and optimization of other comprehensive performance characteristics. The specific technical solution of this composite brightness enhancement film and its beneficial effects will be described in detail below. Please refer to [link / reference]. Figs. 1-2 In a preferred embodiment of this application, the composite brightness enhancement film includes a microlens structure layer 200 and a prism structure layer 100. The microlens structure layer 200 is located above the prism structure layer 100. The microlens structure layer 200 includes a plurality of convex lens structures 210. Each convex lens structure 210 includes a hemispherical upper structure and a polygonal bottom shape. The bottom of each convex lens structure 210 is connected to the bottom of at least one adjacent convex lens structure 210.

[0030] The composite brightness enhancement film proposed in this application mainly consists of a microlens structure layer 200 and a prism structure layer 100. The prism structure layer 100 initially converges and guides incident light through a prism array structure. The microlens structure layer 200 is located above the prism structure layer 100, allowing light to pass through the prism structure layer 100 and the microlens structure layer 200 sequentially during propagation. The microlens structure layer 200 contains multiple convex lens structures 210, each of which consists of a hemispherical upper lens structure and a polygonal bottom shape. The hemispherical upper lens structure effectively converges and diffuses light secondaryly, allowing the light to be more evenly distributed after passing through this structure, thereby improving brightness and uniformity. The design of the polygonal bottom shape (such as hexagon, pentagon, etc.) and the fact that the bottom of each convex lens structure 210 is connected to the bottom of at least one adjacent convex lens structure 210, through a close arrangement, can maximize the area ratio of the convex lens structure 210, improve the efficiency of light control, and at the same time enhance the overall stability of the microlens structure layer 200, reduce structural deformation or damage caused by external factors, and provide structural support for improving wear resistance.

[0031] The hemispherical lens upper structure in the microlens structure layer 200 further converges and diffuses light, distributing it more evenly across the display panel and preventing localized over-brightness or under-brightness, thereby improving the overall brightness of the displayed image. The polygonal bottom-connected convex lens structure 210 design gives the microlens structure layer 200 higher structural stability. When subjected to external friction, compression, or other forces, this tightly packed structure can better disperse stress, reducing localized stress concentration and thus lowering the risk of structural damage, effectively improving the wear resistance of the composite brightness enhancement film.

[0032] The composite brightening film of this application can be manufactured using a combination of mold laser engraving and UV curing coating. Specifically, firstly, a high-precision mold laser engraving process is used to engrave the designed microlens structure on a metal roller, controlling the shape, size, and arrangement of the microlens structure. Next, the UV-curing adhesive is applied to the pre-processed metal mold using a UV curing coating machine. UV curing technology has the advantage of fast curing speed, enabling the adhesive to quickly cure and form a stable microlens structure layer 200 in a short time.

[0033] Specifically, the convex lens structure 210 can be designed by combining two hemispherical lens upper structures of different sizes. The large-size hemispherical lens upper structure has a large aperture (diameter) range of 30μm-80μm, while the small-size hemispherical lens upper structure has a small aperture range of 20μm-60μm. If the large aperture is less than 30μm and the small aperture is less than 20μm, the small aperture will lead to a decrease in optical refractive index, thus reducing the brightness gain effect. Conversely, if the large aperture is greater than 80μm and the small aperture is greater than 60μm, the large aperture will increase the pitch value (center-to-center distance between adjacent structures), which will increase the probability of interference fringes with the module and affect the quality of the displayed image. When the large aperture is within the 30μm-80μm range, the large-size hemispherical lens upper structure has a larger radius of curvature and a larger light-receiving area, effectively capturing and initially converging light incident over a wider angle range. During light propagation, a larger aperture allows for more complete optical refraction and reflection of light after entering the lens structure, thereby improving light utilization and enhancing brightness gain. The small aperture of the upper structure of the small-sized hemispherical lens, ranging from 20μm to 60μm, allows for more precise control of the light propagation direction and distribution. The small-aperture lens, in conjunction with the large-aperture lens, forms a multi-level light control mechanism, ensuring more uniform light processing throughout the entire microlens structure layer 200. Therefore, controlling the aperture within a suitable range guarantees the optical performance and display effect of the composite brightness enhancement film.

[0034] Furthermore, in the microlens structure layer 200, the upper structures of the large-sized and small-sized hemispherical lenses are differentiated not only in diameter but also in height. The height of the upper structure of the large-sized hemispherical lens is in the range of 12μm-32μm, while the height of the upper structure of the small-sized hemispherical lens is controlled between 8μm-24μm. If the height of the upper structure of the large-sized hemispherical lens is less than 12μm and the small size is less than 8μm, the lens's ability to control light will be weakened, and it will be unable to effectively converge and diffuse light, resulting in poor brightness enhancement. If the height of the upper structure of the large-sized hemispherical lens is greater than 32μm and the small size is greater than 24μm, it may increase the complexity of light propagation inside the lens, causing more scattering and reflection, and reducing light utilization.

[0035] Specifically, in the design of the microlens structure layer 200, the ratio of the upper structures of large-sized hemispherical lenses to those of small-sized hemispherical lenses is controlled within the range of 1:6 to 1:30. If the ratio is less than 1:6, it means that the number of upper structures of large-sized hemispherical lenses is relatively excessive, resulting in a large proportion of large apertures; if the ratio is greater than 1:30, it indicates that the number of upper structures of large-sized hemispherical lenses is too small, resulting in a small proportion of large apertures. In both extreme cases, the improvement in the product's wear resistance and desorption capacity will be limited, making it difficult to achieve the intended design performance. A suitable ratio ensures that large and small lenses are evenly distributed in the microlens structure layer 200, reducing local differences in adsorption force caused by structural inhomogeneity. When the external environment changes, the lens structure can adapt better, maintaining a relatively stable adsorption force between the composite brightness enhancement film and the module polarizer, thereby improving desorption capacity.

[0036] Specifically, to achieve more efficient and precise control of light, the convex lens structure 210 can also employ a combination design of three hemispherical lens upper structures of different sizes. The diameter of the large-sized hemispherical lens upper structure is precisely limited to the range of 40μm-100μm; the diameter of the medium-sized hemispherical lens upper structure is controlled between 30μm-80μm; and the diameter of the small-sized hemispherical lens upper structure is in the range of 20μm-60μm. Through the synergistic effect of lenses of different sizes, their respective advantages can be fully utilized. The three hemispherical lens upper structures of different sizes work together to form a multi-level, synergistic light control system. From light collection to convergence to diffusion, each lens plays its unique role, maximizing light utilization and distribution uniformity. Compared with a single-size lens structure, this combined design can improve the brightness, contrast, and color reproduction of the display device.

[0037] Please see further. Figs. 2-4 Specifically, the base shape of the polygon is either hexagonal or pentagonal. A hexagon has six equal sides and angles; its symmetrical structure allows light to enter and exit the lens with a hexagonal base in a more uniform manner. Symmetry helps reduce light scattering and refraction deviations. Furthermore, the close arrangement of hexagons helps reduce interference between adjacent lenses, further optimizing the focusing effect. While the pentagon has slightly less symmetry than the hexagon, its unique shape can produce specific refraction and reflection effects on light. In certain optical applications, such as when specific angles of light deflection or distribution are required, the angle and size of the pentagon's base can be designed to control the direction of light propagation, meeting specific optical design needs.

[0038] Furthermore, the symmetrical structure of the hexagonal base helps reduce the refraction differences of different wavelengths of light when passing through the lens, thereby reducing chromatic aberration. When light passes through a lens with a hexagonal base, the refraction of light in all directions is relatively consistent, allowing different colors of light to focus more closely on the same point, reducing the impact of chromatic aberration on image quality. In certain optical designs, the pentagon can also control chromatic aberration to some extent by adjusting the parameters of its base. Hexagons have a unique ability to be tightly packed; in planar space, hexagons can be joined together in the tightest possible arrangement without gaps. Using a lens structure with a hexagonal base maximizes space utilization, increasing the number of lenses per unit area. More lenses mean more light can be collected and controlled, thus improving the performance of the entire optical system. Simultaneously, the tight arrangement also reduces light leakage and interference between adjacent lenses, improving light utilization.

[0039] The hexagonal geometry is relatively simple, making it highly feasible in mold making and processing. Existing micro-nano fabrication technologies, such as photolithography and etching, can easily produce molds with hexagonal bases. Furthermore, the symmetry of the hexagon helps improve the processing accuracy and consistency of the mold, thus ensuring the high quality and performance of the produced optical components. The structural characteristics of hexagonal and pentagonal bases allow material to fill the mold evenly, reducing defects such as bubbles and voids. Simultaneously, these two shapes also facilitate material flow and solidification during the molding process, improving product yield and quality stability.

[0040] To achieve more efficient light control and better optical performance, the extension direction of the convex lens structure 210 and the extension direction of the prism are arranged in an intersecting pattern. The convex lens structure 210 and the prism can give full play to their respective optical characteristics and achieve synergistic effect in multiple aspects such as light collection, refraction and reflection, thereby improving the performance indicators of the entire optical system.

[0041] Randomly arranged upper structures of hemispherical lenses of different sizes allow for full utilization of the optical characteristics of lenses of varying sizes within a specific area. These upper structures possess different radii of curvature and light-receiving capabilities. Regularly arranged lens structures often produce periodic bright and dark stripes in the display or illumination area, affecting the uniformity of the optical effect. However, when the upper structures of hemispherical lenses of different sizes are randomly arranged, light undergoes multiple refractions, reflections, and scatterings of different directions and intensities as it passes through the randomly distributed lenses. This results in a more random and disordered distribution of light in space, effectively eliminating optical interference caused by regular arrangements. This improves the uniformity of the displayed image and reduces problems such as "muffled patterns" and uneven brightness.

[0042] To further enhance the overall performance of the optical components, a low-haze back coating 300 is introduced into the optical structure. This back coating is uniformly and tightly formed on the prism structure layer 100 through a coating process, located on the side opposite to the microlens structure layer 200. The low-haze back coating 300 has a low haze value, effectively absorbing or reflecting stray light and reducing its interference with imaging light. To ensure a stable and reliable structural connection between the prism structure layer 100 and the microlens structure layer, while guaranteeing optical performance stability and high-quality optical transmission, an adhesive layer is also included between the prism structure layer 100 and the microlens structure layer 200.

[0043] As described above, the composite brightness enhancement film provided in this application mainly consists of a microlens structure layer and a prism structure layer. The prism structure layer initially converges and guides incident light through a prism array structure; the microlens structure layer is located above the prism structure layer, and light passes through the prism structure layer and the microlens structure layer sequentially. The microlens structure layer contains multiple convex lens structures, each consisting of a hemispherical upper structure and a polygonal bottom (such as a hexagon or pentagon), with the bottom connecting to the bottom of at least one adjacent convex lens structure. Lenses of different sizes work together to form a multi-level, synergistic light control system, improving light utilization and distribution uniformity. Simultaneously, the design of convex lens structures of different sizes improves the anti-adsorption performance of the composite brightness enhancement film.

[0044] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A composite brightening film, characterized in that, Including microlens structure layer and prism structure layer; The microlens structure layer is located above the prism structure layer; The microlens structure layer includes multiple convex lens structures, each of which includes a hemispherical upper lens structure and a polygonal bottom shape. The convex lens structure contains two or three sizes of hemispherical upper lens structures. In this configuration, the bottom of each convex lens structure is connected to the bottom of at least one adjacent convex lens structure.

2. The composite brightening film according to claim 1, characterized in that, The convex lens structure includes two sizes of hemispherical lens upper structures, wherein the diameter of the large-sized hemispherical lens upper structure is in the range of 30μm-80μm, and the diameter of the small-sized hemispherical lens upper structure is in the range of 20μm-60μm.

3. The composite brightening film according to claim 2, characterized in that, The height of the upper structure of large-sized hemispherical lenses ranges from 12μm to 32μm, while the height of the upper structure of small-sized hemispherical lenses ranges from 8μm to 24μm.

4. The composite brightening film according to claim 2, characterized in that, The ratio of the number of upper structures of large-sized hemispherical lenses to those of small-sized hemispherical lenses is in the range of 1:6 to 1:

30.

5. The composite brightening film according to claim 1, characterized in that, The convex lens structure includes three sizes of hemispherical lens upper structures: the large-sized hemispherical lens upper structure has a diameter in the range of 40μm-100μm, the medium-sized hemispherical lens upper structure has a diameter in the range of 30μm-80μm, and the small-sized hemispherical lens upper structure has a diameter in the range of 20μm-60μm.

6. The composite brightening film according to any one of claims 1-5, characterized in that, The base of the polygon is either hexagonal or pentagonal.

7. The composite brightening film according to claim 6, characterized in that, The direction of the extension of the convex lens structure intersects with the direction of the extension of the prism.

8. The composite brightening film according to claim 1 or 5, characterized in that, The upper structures of hemispherical lenses of different sizes are randomly arranged.

9. The composite brightening film according to claim 1, characterized in that, It also includes a low-haze back coating layer, which is formed on the prism structure layer and located on the side opposite to the microlens structure layer.

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