Brightness enhancement film, backlight module and display device
By setting a cross-prism structure with height differences in the brightness enhancement film, the problems of easy damage to the prism apex and brightness reduction are solved, achieving a balance between wear resistance and brightness, which is suitable for backlight modules and display devices.
Patent Information
- Application Number
- CN202520536757.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-03-26
AI Technical Summary
The prism apex of traditional brightness enhancement films is easily damaged, resulting in reduced brightness and increased production costs. Existing improvement solutions lead to a further decrease in brightness.
The first prism is higher than the second prism. The cross-section of the first prism is an isosceles triangle with a rounded apex, while the cross-section of the second prism is an isosceles right triangle. The two prisms are arranged in an intersecting manner to enhance optical function and wear resistance.
While improving the wear resistance of the brightening film, it maintains high brightness, solves the problem of brightness decrease after the prism apex corner is changed to a rounded corner, and achieves a balance between scratch resistance and optical performance.
Smart Images
Figure CN223842180U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical film technology, and in particular to a brightness enhancement film, a backlight module, and a display device. Background Technology
[0002] Brightness enhancement films utilize the geometric optical effects of their surface prism microstructures to achieve their light-gathering function. Traditional microstructures are sharp-angled isosceles prisms with a 90-degree apex, making their tops quite fragile and easily damaged during handling or transportation. This damage results in bright white defects on the film surface, reducing yield and increasing production costs. To address this issue, a rounded-angle prism solution has been proposed, changing the sharp angle of the prism to a rounded corner. While this does improve the scratch resistance of the brightness enhancement film surface, it directly leads to a significant decrease in product brightness, defeating the original purpose of using brightness enhancement film components. Currently, no effective solution has been proposed to address these problems. Utility Model Content
[0003] Purpose of the utility model: To provide a brightness enhancement film, a backlight module, and a display device to at least solve one of the problems existing in the prior art.
[0004] Technical solution: A brightness enhancement film, comprising:
[0005] Substrate layer,
[0006] A plurality of first prisms are arranged in an adjacent array along a first direction on the substrate layer; and
[0007] A plurality of second prisms are obliquely disposed at intervals along a second direction on the substrate layer and are respectively fitted with a plurality of first prisms;
[0008] In this configuration, the height of some of the first prisms is higher than the height of some of the second prisms, and the cross-section of the first prism is an isosceles triangle with its apex angle set as a rounded apex angle.
[0009] Preferably, the radius of curvature r of the arc apex is 0.5-5 μm.
[0010] Preferably, the bottom width L1 of the first prism is 20-100 μm.
[0011] Preferably, the cross-section of the second prism is an isosceles right triangle.
[0012] Preferably, the bottom width of the second prism is L2, and the bottom width of the second prism is smaller than the bottom width of the first prism.
[0013] Preferably, the first prisms are arranged in a cross pattern.
[0014] Preferably, the angle θ between the extension direction of the first prism and the extension direction of the second prism is 15-165°.
[0015] Preferably, a spacing is provided between several adjacent second prisms.
[0016] To achieve the above objectives, according to another aspect of this application, a backlight module is also provided.
[0017] The backlight module according to this application includes the brightness enhancement film as described above.
[0018] To achieve the above objectives, according to another aspect of this application, a display device is also provided.
[0019] The display device according to this application includes the backlight module as described above.
[0020] Beneficial Effects: In this embodiment, a plurality of second prisms are introduced. The height of the plurality of first prisms is set higher than that of the plurality of second prisms. The cross-section of the first prism is an isosceles triangle with a rounded apex, while the cross-section of the second prism is an isosceles triangle with a sharp apex. The height difference between the rounded apex first prisms protects the sharp tips of the second prisms from damage caused by friction. At the same time, the setting of the second prisms provides additional prism focusing function, thereby changing the focusing microstructure. This achieves the technical effect of improving the wear resistance of the brightness enhancement film while maintaining high brightness. It also solves the technical problem that changing the prism apex from sharp to rounded, although it helps improve the scratch resistance of the brightness enhancement film surface, directly causes a significant decrease in product brightness, defeating the original purpose of using the brightness enhancement film component. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the prism structure of this utility model.
[0022] The attached figures are labeled as follows:
[0023] 10. Substrate layer;
[0024] 20. First prism;
[0025] 30. Second prism. Detailed Implementation
[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.
[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0028] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.
[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0030] like Figure 1 As shown, this application relates to a brightness enhancement film, a backlight module, and a display device. The brightness enhancement film includes a substrate layer 10, which is the base material or substrate to which the optical film or coating is attached, enabling good fixation and support; simultaneously, it can cooperate with other film layer structures to achieve multiple functional effects. Preferably, the substrate layer 10 is PET, PC, PMMA, PE, PVC, or PS. This allows for the selection of various materials, making the desired effect easily achievable.
[0031] A plurality of first prisms 20 are arranged in an adjacent array on the substrate layer 10 along a first direction; the first prisms 20 are the main optical elements and are arranged sequentially adjacent to each other on the substrate layer 10 along a specific direction (the first direction); wherein, the first direction can be the X-axis direction or the Y-axis direction of the substrate layer 10.
[0032] A plurality of second prisms 30 are obliquely disposed at intervals along a second direction on the substrate layer 10 and are respectively fitted with a plurality of first prisms 20. To compensate for the loss of brightness, the second prisms 30 are introduced in an included angle direction. The second prisms 30 are another main optical element, which are obliquely disposed along the second direction on the upper surface of the substrate layer 10 and respectively introduced into the first prisms 20, thereby forming a cross-shaped distribution. Thus, the complete light-gathering function is dually manifested by the first prisms 20 and the second prisms 30, thereby improving the brightness of the rounded corner wear-resistant brightening film. The second direction can be the X-axis direction or the Y-axis direction of the substrate layer 10, or any angle direction intersecting with the first direction.
[0033] Prism structures are conventional prism structures in the field of optical films, and can be used for various optical applications such as beam splitting, focusing, and beam splitting. At the same time, these prisms can be arranged into various different geometric shapes to achieve different optical functions.
[0034] It should be noted that the first prism 20 and the second prism 30 are formed by methods including but not limited to sputtering, evaporation, spraying, coating or mold pressing to obtain the desired compound prism structure.
[0035] In this configuration, the height of some of the first prisms 20 is higher than the height of some of the second prisms 30, and the cross-section of the first prism 20 is an isosceles triangle with a rounded apex, which improves the wear resistance of the brightness enhancement film. By setting the height of the second prism 30 to be lower than the height of the first prism 20, and the cross-section of the second prism 30 being an isosceles right triangle, the lost brightness can be compensated for, thereby achieving the effect of improving luminance.
[0036] This application also has the following beneficial effects:
[0037] Optimizing light propagation efficiency: The height of the first prism 20 is higher than that of the second prism 30, allowing the first prism 20 to play a dominant role in the optical structure and more effectively control the light propagation path. This ensures that the main light rays are precisely focused or reflected when passing through the first prism 20, while the second prism 30 is used to fine-tune the direction or distribution of the light, thereby improving the overall optical efficiency.
[0038] Enhanced mechanical strength and durability: The rounded apex design not only contributes to optical performance but also reduces damage to the prism caused by stress concentration during manufacturing or use; it improves the mechanical strength of the prism, making it more durable, especially in applications requiring frequent operation or exposure to harsh environments.
[0039] Achieving uniform light distribution: By intersecting the first and second prisms, the directional regularity of a single prism group is disrupted, which helps to alleviate the interference of the display screen caused by a single prism group.
[0040] As can be seen from the above description, this application achieves the following technical effects:
[0041] In this embodiment, a plurality of second prisms 30 are introduced. The height of a plurality of first prisms 20 is set higher than the height of a plurality of second prisms 30. The cross-section of the first prism 20 is an isosceles triangle with a rounded apex, while the cross-section of the second prism 30 is an isosceles triangle with a sharp apex. The height difference between the rounded apex first prisms protects the sharp tips of the second prisms from damage caused by friction. At the same time, the setting of the second prisms provides additional prism focusing function, thereby changing the focusing microstructure. This achieves the technical effect of improving the wear resistance of the brightness enhancement film while maintaining high brightness. This solves the technical problem that changing the prism apex from sharp to rounded, although it helps improve the scratch resistance of the brightness enhancement film surface, directly causes a significant decrease in product brightness, defeating the original purpose of using the brightness enhancement film component.
[0042] Furthermore, the radius of curvature r of the rounded corner is 0.5-5µm. It can be understood that setting the corner radius r to 0.5-5µm can improve wear resistance and also allow for a variety of sizes to be selected, thus meeting diverse usage requirements.
[0043] It should be noted that if the radius of curvature r of the first prism 20 is too small, it will not provide sufficient scratch resistance.
[0044] If the radius of curvature of the first prism 20 is too large, the contact area will be too large, resulting in inter-film adsorption and obvious stripe marks on the image. Therefore, setting the radius of curvature within the above range can ensure good optical and physical performance.
[0045] Furthermore, the bottom width L1 of the first prism 20 is 20-100µm. This allows for a variety of bottom width options to be available, thus meeting the needs of various application scenarios.
[0046] Furthermore, the cross-section of the second prism 30 is an isosceles right triangle. It can be understood that by adopting an isosceles right triangle structure, the second prism 30 possesses symmetry and high efficiency in optical function, enabling it to reflect or refract light at a specific angle.
[0047] Furthermore, the bottom width of the second prism 30 is L2, and the bottom width of the second prism 30 is smaller than the bottom width of the first prism 20;
[0048] Among them, L2 is the size of a typical traditional brightness enhancement film prism, which is between 20-100um;
[0049] It is important to understand that if L2 is too large, it will not only exceed the first prism and fail to meet the protection purpose, but also result in visually undesirable image quality; if L2 is too small, the optical efficiency will be too poor to substantially improve brightness. Therefore, L2 is set between 20-100µm; this ensures good mechanical and optical performance, thereby meeting the usage requirements.
[0050] Furthermore, the first prism 20 is arranged in a crisscross pattern. This can be understood to enhance the overall performance of the optical structure; for example, by improving light uniformity or adjusting the viewing angle range.
[0051] Furthermore, the angle θ between the extending direction of the first prism 20 and the extending direction of the second prism 30 is 15-165°. This ensures the prism structure has good optical performance, thus avoiding poor optical effects due to excessively large or small angles, and mitigating display screen interference caused by a single regular prism group.
[0052] Furthermore, a spacing is provided between several adjacent second prisms 30. It can be understood that by providing a spacing d between adjacent second prisms 30, the density of the prisms can be adjusted, thereby improving brightness. The spacing can be a fixed spacing or a variable spacing.
[0053] Furthermore, the first prism 20 and the second prism 30 are made of photocurable hard resin with a refractive index range of 1.5-1.7. It is understandable that by selecting a photocurable hard resin with a higher refractive index, the brightness of the enhancement film can be improved while also maintaining scratch resistance.
[0054] This application also has the following beneficial effects:
[0055] 1. Introduce a second set of cross prisms. The second set of prisms has a 90-degree sharp angle and is 20 degrees lower in height than the first prism, providing additional optical benefits to compensate for the rounded corner prism.
[0056] 2. The spacing of the second prism 30 is adjustable, which helps to adjust the interference phenomenon.
[0057] 3. This solution is applicable to single-sheet brightening film or laminated brightening film (POP).
[0058] The following examples further illustrate this point:
[0059] The testing items for the brightness enhancement film provided by this utility model include, but are not limited to: scratch resistance test and luminance test.
[0060] Scratch resistance test: The brightening film of the following embodiments is subjected to a scratch test using a scratch resistance tester with a specific weight, and the scratch test is performed on the back of the diffusion film.
[0061] Brightness test: The brightness enhancement film of the following embodiment was installed in the backlight module, and the brightness was measured using a BM-7AC brightness meter. The screen condition was then observed.
[0062] Example 1
[0063] The bottom width L1 of the first prism 20 is 70 μm, and the radius of curvature r of the arc apex of the first prism 20 is 2 μm; the bottom width L2 of the second prism 30 is 60 μm, its apex is a sharp angle, and the distance between adjacent second prisms 30 is 100 μm; the included angle θ between the first prism 20 and the second prism 30 is 30°.
[0064] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8259 nits, brightness ratio of 130%, and scratch resistance of 1200g.
[0065] Example 2
[0066] The difference from Example 1 is that the radius of curvature r of the arc apex of the first prism 20 is 0.5 μm.
[0067] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8570 nits, brightness ratio of 135%, and scratch resistance of 500g.
[0068] Example 3
[0069] The difference from Example 1 is that the radius of curvature r of the arc apex of the first prism 20 is 5 μm.
[0070] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 7811 nits, brightness ratio of 123%, and scratch resistance of 2000g.
[0071] Example 4
[0072] The difference from Example 1 is that the bottom width L2 of the second prism 30 is 20 μm.
[0073] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8088 nits, brightness ratio of 128%, and scratch resistance of 1200g.
[0074] Example 5
[0075] The difference from Example 1 is that the included angle θ between the first prism 20 and the second prism 30 is 90°.
[0076] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8449 nits, brightness ratio of 133%, and scratch resistance of 1200g.
[0077] Example 6
[0078] The difference from Example 1 is that the included angle θ between the first prism 20 and the second prism 30 is 165°.
[0079] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8102 nits, brightness ratio of 128%, and scratch resistance of 1200g.
[0080] Example 7
[0081] The difference from Example 1 is that the spacing between adjacent second prisms 30 is 10 μm.
[0082] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 10594 nits, brightness ratio of 167%, and scratch resistance of 1200g.
[0083] Example 8
[0084] The difference from Example 1 is that the spacing between adjacent second prisms 30 is 1000um.
[0085] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 6366 nits, brightness ratio of 101%, and scratch resistance of 1200g.
[0086] Comparative Example 1
[0087] The difference from Embodiment 1 is that the first prism 20 adopts a fully rounded corner structure and does not have the structure of the second prism 30.
[0088] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 6332 nits, brightness ratio of 100%, and scratch resistance of 1200g.
[0089] Comparative Example 2
[0090] The difference from Embodiment 1 is that the apex of the first prism 20 has a sharp corner structure and does not have the structure of the second prism 30.
[0091] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 6758 nits, brightness ratio of 107%, and scratch resistance of 50g.
[0092] Comparative Example 3
[0093] The difference from Example 1 is that the radius of curvature r of the arc apex of the first prism 20 is 0.4 μm.
[0094] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 8637 nits, brightness ratio of 136%, and scratch resistance of 300g.
[0095] Comparative Example 4
[0096] The difference from Example 1 is that the radius of curvature r of the arc apex of the first prism 20 is 6 μm.
[0097] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 7606 nits, brightness ratio of 120%, and scratch resistance of 2000g.
[0098] Comparative Example 5
[0099] The difference from Example 1 is that the included angle θ between the first prism 20 and the second prism 30 is 170°.
[0100] At this point, the performance parameters of the brightness enhancement film, as tested, are: brightness of 7666 nits, brightness ratio of 121%, and scratch resistance of 1200g.
[0101] The results of each embodiment and comparative example are shown in Table 1:
[0102]
[0103] The test results above show that:
[0104] 1. As can be seen from Example 1 and Comparative Examples 1-2, the brightness enhancement film of this utility model adds a second prism 30, and the apex angle of the second prism 30 is a sharp angle, which can not only improve the brightness gain effect of the brightness enhancement film, but also have good scratch resistance.
[0105] 2. As can be seen from Examples 1-3 and Comparative Examples 1-4, as the radius of curvature increases, the wear resistance is significantly improved. When the radius of curvature of the first prism's rounded corner is 0.4 μm, the apex is still too sharp and the wear resistance is insufficient. When the radius of curvature of the first prism's rounded corner is 6 μm, the apex is too rounded, which limits the improvement in optical efficiency and causes abnormal image adsorption. At the same time, due to the introduction of the second set of prisms, additional light-gathering effect is provided, which significantly improves the product brightness, which is also higher than that of a single full-sharp-angle prism.
[0106] 3. As can be seen from Examples 1 and 4, as the bottom width of the second prism 30 decreases, the luminous efficiency of the prism decreases. Therefore, the bottom width of the second prism must still follow the conventional size of 20-100um for brightening film prisms and cannot be too small.
[0107] 4. As can be seen from Examples 1, 5-6 and Comparative Example 5, as the angle between the second prism 30 and the first prism 20 deviates further from the orthogonal state, the brightness enhancement effect decreases.
[0108] 5. As can be seen from Examples 1 and 7-8, when the density of the second prism 30 increases, it approaches the POP structure, and the brightness is greatly improved; when the density of the second prism 30 decreases, the brightness improvement effect is greatly reduced.
[0109] In summary, based on the embodiments and comparative results, it can be seen that by introducing the second prism 30, the present invention can improve the wear resistance while simultaneously increasing the brightness of the brightening film.
[0110] This application also relates to a backlight module, including the brightness enhancement film as described above.
[0111] This application also relates to a brightness enhancement film for POP-type lamination, including the brightness enhancement film as described above.
[0112] The scratch-resistant double-interlaced prism structure of this invention can be applied not only to single-sheet brightening films but also to POP-type laminated brightening films, serving as an upper prism structure to improve the surface scratch resistance of POP products.
[0113] This application also relates to a display device, including the backlight module described above.
[0114] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.
Claims
1. A brightness enhancement film, characterized in that, include: Substrate layer (10), A plurality of first prisms (20) are arranged in an adjacent array along a first direction on the substrate layer (10); and A plurality of second prisms (30) are obliquely disposed at intervals along the second direction on the substrate layer (10) and are respectively fitted with a plurality of first prisms (20); Among them, the height of some of the first prisms (20) is higher than the height of some of the second prisms (30), and the cross-section of the first prism (20) is an isosceles triangle with its apex angle set as a rounded apex angle.
2. The brightening film according to claim 1, characterized in that, The radius of curvature r of the arc apex is 0.5-5 μm.
3. The brightening film according to claim 1, characterized in that, The bottom width L1 of the first prism (20) is 20-100um.
4. The brightening film according to claim 1, characterized in that, The cross-section of the second prism (30) is an isosceles right triangle.
5. The brightening film according to claim 3, characterized in that, The bottom width of the second prism (30) is L2, and the bottom width of the second prism (30) is smaller than the bottom width of the first prism (20).
6. The brightening film according to claim 1, characterized in that, The first prism (20) is distributed in a cross pattern with the first prism (20).
7. The brightening film according to claim 1, characterized in that, The angle θ between the extension direction of the first prism (20) and the extension direction of the second prism (30) is 15-165°.
8. The brightening film according to claim 1, characterized in that, A spacing is provided between several adjacent second prisms (30).
9. A backlight module, characterized in that, Includes the brightening film as described in any one of claims 1-8.
10. A display device, characterized in that, Includes the backlight module as described in claim 9.