Optical film with prism microstructure and backlight module

Abstract

The utility model relates to an optical film with a prism microstructure and a backlight module, and aims to realize single-piece production of the optical film through design, improve the production efficiency and reduce the cost. The optical film comprises a first prism group, a second prism group, a base material layer and a back coating atomization layer, the two groups of prisms are orthogonally arranged to form an inverted quadrangular pyramid space structure, light is effectively managed, and high light transmittance, low reflectivity and good light guidance are ensured. In addition, the optical performance is further optimized by accurately controlling the height, the shape, the bottom edge width, the vertex angle, the refractive index and other parameters of the prism. And meanwhile, a back coating atomization layer is optionally additionally arranged on the back surface of the base material layer, so that glare and light reflection are reduced, and the visual comfort is improved. According to the optical film, the production process is simplified, the excellent optical performance is kept, the optical film is suitable for the backlight module, the display brightness and uniformity are remarkably improved, and remarkable technical progress and wide application prospects are achieved.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to an optical film and a backlight module having a prismatic microstructure. Background Art

[0002] With the development of display technology, optical brightening film, as a key component to improve display effects and enhance visual experience, its performance and manufacturing cost have increasingly become the focus of attention in the industry. Traditional optical brightening films mostly adopt a composite film structure, that is, multiple layers of thin films with microstructures are laminated by bonding glue to achieve functions such as light diffusion and brightness uniformity. However, this production method has significant disadvantages: first, the bonding of multiple layers of films not only increases material consumption and increases material costs, but also the adhesion of glue to the prism peaks during the bonding process often leads to a decrease in brightness, affecting the display effect; secondly, the complex bonding process reduces production efficiency, increases labor costs, and is not conducive to large-scale production; thirdly, the existing four-sided pyramid structure is easily damaged during long-term use due to its sharp top angle, and its scratch resistance and anti-interference performance are insufficient, which limits the product's service life and application scenarios.

[0003] In particular, designs based on single-film prism structures (such as 3-film / 4-film structures), while simplifying the structure to some extent, also face the challenges of low assembly efficiency and high production costs. Furthermore, these structures are still insufficient in improving scratch resistance and anti-interference performance, making it difficult to meet the growing market demand for high-performance, low-cost optical brightness enhancement films.

[0004] Therefore, it is necessary to optimize structural design and improve production processes to achieve a dual improvement in assembly efficiency and production efficiency, while reducing material usage costs and significantly improving the product's scratch resistance, shielding and anti-interference performance. Utility Model Content

[0005] The purpose of the present application is to provide an optical film with a prismatic microstructure, which can transform the traditional optical film production process into a single-sheet production without affecting the optical performance, avoiding the use of multiple stacking solutions, effectively reducing material usage costs and improving production efficiency. The optical film with a prismatic microstructure of the present application includes a first prism group, a second prism group, a substrate layer, and a back-coated atomized layer;

[0006] The first prism group and the second prism group are orthogonally arranged to form an inverted quadrangular pyramid space;

[0007] The prisms in the first prism group have the same height and the prisms in the second prism group have the same height, and the height of the prisms in the first prism group is the same as or different from the height of the prisms in the second prism group;

[0008] The prisms in at least one of the first prism group and the second prism group have an up-and-down shaking appearance.

[0009] In one embodiment, the cross-sections of the prisms in the first prism group and the second prism group are symmetrical shapes with vertex angles.

[0010] In one embodiment, the base width of the prisms in the first prism group and the second prism group is between 10 μm and 80 μm.

[0011] In one embodiment, the vertex angles of the prisms in the first prism group and the second prism group are in the range of 60-95°.

[0012] In one embodiment, the refractive index of the prisms in the first prism group and the second prism group is in the range of 1.5 to 1.7.

[0013] In one embodiment, the substrate has a thickness in the range of 20 μm to 300 μm.

[0014] In one embodiment, the surface roughness of the back-coated atomized layer is in the range of 1 μm to 10 μm.

[0015] In one embodiment, the haze of the back-coated atomized layer is in the range of 50% to 99%.

[0016] In addition, the present application also provides a backlight module, which includes the aforementioned optical film with a prismatic microstructure.

[0017] Compared to the prior art, the present invention has the following advantages: The optical film with a prismatic microstructure, formed by orthogonally arranging a first prism group and a second prism group to form an inverted quadrangular pyramid spatial structure, achieves a single-sheet production model for the optical film, avoiding the complex processes and additional costs associated with stacking multiple sheets. This also simplifies the production process, improves production efficiency, effectively reduces material usage, and lowers overall production costs. By precisely controlling key parameters such as the height, shape, base width, vertex angle, and refractive index of the prisms in the first and second prism groups, optical performance is ensured, allowing light to be effectively managed and controlled as it passes through the prisms. This ensures high transmittance, low reflectivity, and excellent light guidance for the optical film, meeting the high optical performance requirements of high-end display devices. The present invention also adds a back-coated atomized layer on the back of the substrate layer to achieve soft light scattering, effectively reducing glare and reflections, and providing users with a more comfortable and softer visual experience. This design is particularly suitable for electronic devices such as liquid crystal displays, mobile phone screens, and tablet computers, and can significantly enhance the market competitiveness of the products. The optical film with prismatic microstructure in this application is not only suitable for backlight modules to improve display brightness and uniformity, but also realizes innovation in the production mode of optical films through the unique prismatic microstructure design, which not only improves production efficiency and reduces costs, but also maintains excellent optical performance and enhances the visual experience of the product. It has significant technological progress and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 3D structure diagram of an optical film with a prismatic microstructure according to an embodiment of the present application;

[0019] Figure 2 It is a schematic diagram of the three-dimensional structure of an optical film with a prismatic microstructure in another embodiment of the present application.

[0020] Explanation of reference numerals: 110, first prism group; 120, second prism group; 200, substrate layer; 300, back-coating atomized layer. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] As used herein, the terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0023] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] See also Figures 1 to 2 As shown, an optical film with a prismatic microstructure in a preferred embodiment of the present application is suitable for being a multifunctional brightening film that can be used alone, so as to reduce material usage costs, improve production efficiency, improve assembly efficiency, and reduce personnel usage costs. At the same time, it can also reduce light loss and improve scratch resistance, shielding, and interference performance. The optical film with a prismatic microstructure includes a first prism group 110, a second prism group 120, a substrate layer 200, and a back-coated atomized layer 300. The first prism group 110 and the second prism group 120 are orthogonally arranged to form an inverted quadrilateral space. The heights of the prisms in the first prism group 110 are the same, and the heights of the prisms in the second prism group 120 are the same or different from the heights of the prisms in the second prism group 120. The prisms in at least one of the first prism group 110 and the second prism group 120 have an up and down shaking appearance.

[0025] The first prism group 110 and the second prism group 120 are intertwined in a unique orthogonal layout, forming a three-dimensional inverted quadrangular pyramid structure. This layout enhances the structural stability of the film and effectively manages light through multiple refraction and reflection paths, achieving uniform light distribution over a wider viewing angle. Within the same prism group, all prisms maintain a consistent height, ensuring consistent light processing. The prism heights of the first prism group 110 and the second prism group 120 can be designed to be the same to enhance specific optical effects, or to have slight differences to fine-tune light distribution to meet the light control requirements of different application scenarios. In at least one prism group, the top or bottom edge of the prism adopts a non-planar shape that jitters up and down, introducing subtle changes in the curvature. This can more effectively scatter or focus light, reduce glare, enhance visual comfort, and potentially improve color saturation and contrast to a certain extent. Through orthogonal prism arrays and adjustable prism height, this optical film precisely controls the propagation path and distribution of light, making it suitable for a variety of display devices and lighting systems, enhancing image uniformity and clarity. This precise control of light reduces unnecessary energy loss while enhancing light scattering, resulting in a softer, more comfortable viewing experience and more natural, richer colors. Due to its flexible optical design, this optical film can be widely used in a variety of products, including mobile phones, tablets, televisions, monitors, and lighting fixtures, meeting the light management needs of diverse scenarios.

[0026] The back-coated atomized layer 300 is arranged on the back side of the substrate layer 200. The back-coated atomized layer 300 is applied to the back side of the substrate layer 200. The back-coated atomized layer 300 effectively reduces the reflection and glare on the back side through its unique atomization effect. The back-coated atomized layer 300 can also block or blur the line of sight on the back side to a certain extent, thereby enhancing the privacy protection function of the product. This is especially important for occasions where it is necessary to protect the internal structure or avoid information leakage. The back-coated atomized layer 300 usually has certain wear resistance, corrosion resistance and weather resistance, and can effectively protect the substrate layer 200 from erosion and damage from the external environment. The back-coated atomized layer 300 can also be customized according to specific needs, such as adding functional coatings such as anti-static and easy-to-clean. These additional functions further enhance the practicality and user experience of the product. The back-coated atomized layer 300 is obtained by machining a microstructure using a light curing process or a hot pressing process. The machined microstructure refers to using a diamond tool to directly carve irregular sized concave and convex structures on a metal mold. This microstructure is then printed with UV adhesive or hot pressed to obtain the atomized layer.

[0027] Specifically, the cross-sections of the prisms in the first prism group 110 and the second prism group 120 are symmetrical shapes with vertex angles. The cross-section of the prism adopts a symmetrical design and has a shape with a clear axis of symmetry. This design allows the light to be evenly distributed along the axis of symmetry when propagating inside the prism, reducing the deflection and loss of light and improving optical performance. The symmetrical shape of the prism cross-section design allows the light to maintain a high refraction and reflection efficiency when propagating inside the prism. Due to the symmetry of the prism cross-section, the light can be evenly distributed along the axis of symmetry when passing through the prism group, effectively reducing the problem of uneven light distribution and improving the uniformity and clarity of the picture. The symmetrical shape design simplifies the manufacturing process of the prism, making the manufacturing process of the prism more precise and controllable. At the same time, it also reduces the defective rate in the manufacturing process and improves the overall quality of the product. When subjected to external forces, the symmetrically shaped prisms can better disperse and resist stress, thereby improving the structural stability and durability of the optical film.

[0028] Specifically, the bottom width of the prisms in the first prism group 110 and the second prism group 120 is between 10μm and 80μm. The bottom width of the prism is set between 10μm and 80μm to ensure the fineness of the prism structure at the microscopic level. The narrower bottom width can provide a denser prism arrangement, thereby enhancing the light control ability and optical effect, while the wider bottom width is conducive to improving manufacturing stability and reducing costs. During the manufacturing process, through advanced micro-nano processing technologies such as photolithography and etching, the bottom width of the prism can be precisely controlled to ensure that it is within the set range. The optimized bottom width enables the prism group to better control the propagation direction and distribution range of light, thereby improving the overall performance of the optical film. By setting a reasonable bottom width range, the stability and efficiency of the manufacturing process can be improved while ensuring optical performance. At the same time, it is also conducive to reducing manufacturing costs, so that this high-performance optical film can be more widely used in various fields. By adjusting the base width of the prism, the needs of different scenarios can be flexibly met. For example, in display devices that require high clarity and color accuracy, a prism group with a narrower base width can be used, while in lighting systems that require a wide range of light distribution and reduce glare, a prism group with a slightly wider base width can be used.

[0029] Specifically, the vertex angles of the prisms in the first prism group 110 and the second prism group 120 are in the range of 60 to 95 degrees. The vertex angle of the prism is a key factor in determining the internal propagation path and emission direction of light. Setting the vertex angle within the range of 60 to 95 degrees can cause moderate refraction and reflection of light inside the prism, thereby achieving precise control of the propagation direction of light. Different vertex angle configurations will have different effects on the propagation of light. By adjusting the vertex angle, it is possible to optimize various effects such as light dispersion, convergence, and deflection. The appropriate vertex angle design enables the prism group to more effectively control the propagation direction and distribution range of light. In display devices, this helps to improve the uniformity and clarity of the picture. By optimizing the vertex angle, the loss of light inside the prism can be reduced and the optical efficiency can be improved. This means that under the same input light intensity, a stronger output light intensity can be obtained, thereby improving the overall optical performance.

[0030] Specifically, the refractive index of the prisms in the first prism group 110 and the second prism group 120 is within a range of 1.5 to 1.7. This narrow and efficient refractive index range was selected to take into account the practical needs of optical design and performance optimization. Within this range, the prism material exhibits good light transmittance, low optical dispersion, and moderate refractive index variation, thereby ensuring high transmission efficiency and low energy loss when light passes through the prism. A moderate refractive index helps reduce light reflection losses at the prism interface, enhancing light transmittance, and thus improving the imaging clarity and contrast of the entire optical system. Prism materials generally have good dispersion control properties, which can reduce color shift caused by refractive index differences between light wavelengths (i.e., dispersion), thereby maintaining image color accuracy and fidelity. Selecting the appropriate refractive index allows designers to more flexibly adjust the size, shape, and layout of the prisms to accommodate the space constraints and performance requirements of different application scenarios. Materials within this refractive index range also have good temperature and chemical stability, maintaining stable optical performance under harsh environmental conditions and extending the service life of the optical system.

[0031] Specifically, the thickness of the substrate is in the range of 20μm to 300μm. The thickness of the substrate directly affects the transmission, reflection and interference of light. In optical films, a substrate of appropriate thickness can reduce the scattering and absorption of light, improve the transmittance and imaging quality, and by controlling the thickness, specific optical effects such as anti-reflection films and reflectors can also be achieved. Thicker substrates usually have better thermal stability and heat dissipation performance, which helps to quickly dissipate the heat generated inside the device to prevent overheating damage. While ensuring performance, a reasonable selection of substrate thickness helps to reduce production costs. A substrate that is too thick will increase material consumption and processing difficulty, while a substrate that is too thin may lead to increased costs due to manufacturing difficulties and yield issues. Therefore, choosing a suitable thickness within the range of 20μm to 300μm can maximize cost-effectiveness. This wide thickness range enables the substrate to be widely used in various fields and scenarios.

[0032] Specifically, the surface roughness of the back-coated atomized layer 300 is in the range of 1 μm to 10 μm. Within the roughness range of 1 μm to 10 μm, the surface of the back coating can form tiny irregular structures, which can effectively scatter light, causing the light to be reflected and refracted multiple times on the surface of the back coating, thereby creating a soft and uniform visual effect. As the surface roughness increases, the scattering effect of the back coating will also increase accordingly, thereby blocking or blurring the line of sight from the back to a certain extent. This enhanced privacy protection function is particularly important for occasions where internal structures need to be protected. Appropriate surface roughness also helps to improve the wear resistance, corrosion resistance and weather resistance of the back coating. The rough surface structure can increase the contact area between the coating and the surrounding environment, improve the adhesion of the coating, and reduce damage caused by external friction or chemical erosion.

[0033] Specifically, the haze of the back-coated atomized layer 300 is in the range of 50% to 99%. The haze in the range of 50% to 99% allows the back-coated atomized layer 300 to provide more space for product design. The appropriate haze setting can reduce glare and reflection, and improve the user's visual comfort. In a display device, the back-coated atomized layer 300 can effectively reduce light interference from the back of the screen, allowing users to view the screen content more clearly. At the same time, the soft visual effect also helps to relieve visual fatigue caused by watching the screen for a long time. Although haze has little direct correlation with heat dissipation performance, in some designs, the back-coated atomized layer 300 may be combined with a heat dissipation structure. For example, by embedding a heat dissipation channel in the back coating or using a material with heat dissipation function, the heat dissipation efficiency can be improved while maintaining a high haze.

[0034] In addition, the present application also provides a backlight module, which includes the aforementioned optical film with a prismatic microstructure. The optical film with a prismatic microstructure, through its unique microstructure design, can effectively collect and redirect light from the light source, so that the light is more concentrated and evenly irradiated onto the display panel, significantly improving the backlight efficiency, reducing energy consumption while improving the brightness and uniformity of the display effect. The optical film with a prismatic microstructure can also effectively reduce the loss of light at a specific angle when regulating the direction of light. By precisely controlling the distribution and intensity of light, the optical film with a prismatic microstructure can also enhance the color saturation and contrast of the display image to a certain extent. Using the optical film with a prismatic microstructure as one of the key components of the backlight module not only simplifies the structural design of the module, but also improves the integration between the components. At the same time, the optical film material that has been rigorously tested and optimized also ensures the stability and reliability of the backlight module during long-term use.

[0035] Specific implementation methods: Next, some specific implementation methods are introduced and relevant performance comparisons are performed.

[0036] Comparative Example 1: In this comparative example, three lower diffusion films are used. Although it is a low-cost solution, its brightness ratio is low and the optical efficiency is the worst.

[0037] Comparative Example 2: This comparative example belongs to the standard four-film solution, with upper and lower diffusion films paired with two orthogonal prism sheets. However, the prism sheets themselves have poor wear resistance, and orthogonal prisms are prone to image interference.

[0038] Comparative Example 3, a three-film solution, uses a POP composite film to replace two orthogonal prism sheets. The advantage is that the thickness of the prism sheet substrate can be thinned, and one less film sheet is required during assembly compared to Comparative Example 2. The disadvantage is that the prism sheet still retains the disadvantages of poor friction resistance and anti-interference ability, and the brightness is lower than that of two orthogonal prism sheets.

[0039] Comparative Example 4 is an alternative to the traditional diffuser film + prism sheet + diffuser film solution, replacing the upper diffuser film and one prism sheet with an MOP composite film. While the brightness level is lower, the advantage is better wear resistance.

[0040] Comparative Example 5: A single tetrahedral film was coated on the back with the machined back coating described in this application. The tetrahedral structure provides excellent brightness performance, and the machined back coating can controllably provide high light transmittance while also providing high shielding properties, resulting in high overall optical efficiency. However, this solution suffers from the poor wear resistance of the tetrahedral structure, resulting in a low yield, and the overly regular microstructure can cause severe image interference.

[0041] Table 1 Specific methods and test results of various embodiments

[0042]

[0043] Through the above tests, it can be seen that in the backlight module design scheme, five different schemes have different test results. From the three-sheet lower diffusion film scheme with low cost but low brightness and poor optical efficiency, to the standard four-sheet film configuration with good brightness but poor wear resistance and easy interference of the prism sheet, to the attempt to replace the prism sheet with POP composite film, which has reduced the thickness but has not completely solved the wear resistance and brightness problems, and the MOP composite film, which has replaced some components to improve wear resistance but has poor brightness, a compromise solution, and finally to the design of a single square pyramid film combined with a machined back coating, which has made breakthroughs in brightness and optical efficiency, but faces the challenges of poor wear resistance and image interference of the square pyramid structure. The backlight module formed by the double prism film provided in this application has a better balance between brightness, wear resistance, optical efficiency and cost control.

[0044] As can be seen from the foregoing, this application provides an innovative optical film with a prismatic microstructure. This film utilizes a unique inverted quadrangular pyramid spatial structure design, consisting of a first prism group and a second prism group arranged orthogonally. This allows for single-sheet production of the optical film, completely eliminating the traditional complex production process of stacking multiple sheets. This effectively reduces material costs and significantly improves production efficiency. By finely controlling key parameters such as prism height, shape, base width, vertex angle, and refractive index, this optical film ensures excellent optical performance, including high transmittance, low reflectivity, and superior light guidance, perfectly meeting the stringent optical quality requirements of high-end display devices.

[0045] In addition, this application also creatively adds a back-coated atomized layer on the back of the substrate layer of the optical film. This layer has a precise surface roughness and an adjustable haze range, effectively achieving soft scattering of light, reducing glare and reflection, and bringing users a more comfortable and soft visual enjoyment. This design not only enhances the visual experience of the product, but also broadens the application range of optical films in electronic devices such as liquid crystal displays, mobile phone screens, and tablet computers. The optical film with a prismatic microstructure proposed in this application not only achieves innovation in the production model and significantly improves production efficiency and cost-effectiveness, but also further enhances the visual experience of the product by adding a back-coated atomized layer while maintaining excellent optical performance.

[0046] The above is only a specific implementation of the present application. Any other improvements made based on the concept of the present application are considered to be within the scope of protection of the present application.

Claims

1. An optical film having a prismatic microstructure, characterized in that: It comprises a first prism group (110), a second prism group (120), a substrate layer (200), and a back-coated atomized layer (300); The first prism group (110) and the second prism group (120) are orthogonally arranged to form an inverted quadrangular pyramid space; The prisms in the first prism group (110) have the same height and the prisms in the second prism group (120) have the same height, and the height of the prisms in the first prism group (110) is the same as or different from the height of the prisms in the second prism group (120); The prisms in at least one of the first prism group (110) and the second prism group (120) have an up-and-down shaking appearance.

2. The optical film having a prismatic microstructure according to claim 1, wherein: The cross-sections of the prisms in the first prism group (110) and the second prism group (120) are symmetrical shapes with vertex angles.

3. The optical film having a prismatic microstructure according to claim 2, wherein: The bottom widths of the prisms in the first prism group (110) and the second prism group (120) are between 10 μm and 80 μm.

4. The optical film having a prismatic microstructure according to claim 2, wherein: The vertex angles of the prisms in the first prism group (110) and the second prism group (120) are within the range of 60° to 95°.

5. The optical film having a prismatic microstructure according to claim 1, wherein: The refractive index of the prisms in the first prism group (110) and the second prism group (120) is within the range of 1.5 to 1.

7.

6. The optical film having a prismatic microstructure according to claim 1, wherein: The thickness of the substrate is in the range of 20 μm to 300 μm.

7. The optical film having a prismatic microstructure according to claim 1, wherein: The surface roughness of the back-coated atomized layer (300) is within the range of 1 μm to 10 μm.

8. The optical film having a prismatic microstructure according to claim 7, wherein: The haze of the back-coated atomized layer (300) is in the range of 50% to 99%.

9. A backlight module, characterized in that: The optical film comprises the optical film having a prismatic microstructure according to any one of claims 1 to 8.

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