Composite film and backlight module

Abstract

The utility model relates to a composite film and a backlight module, and relates to the field of display technology, the composite film comprises a reflective brightness enhancement film layer and a prism layer, and the brightness enhancement film layer and the prism layer are connected through a fitting glue layer; the prism layer is provided with a plurality of first prism grooves and a plurality of second prism grooves, the plurality of first prism grooves and the plurality of second prism grooves are respectively arranged along a first direction and a second direction, and a plurality of prism structures are formed between the plurality of first prism grooves and the plurality of second prism grooves. The first prism groove and the second prism groove are designed in the prism layer and arranged in the first direction and the second direction respectively, light can be bidirectionally refracted, the viewing angle range is expanded, and the visual experience is improved; the reflection type brightness enhancement film layer has high reflectivity, light rays emitted by the light source can be reflected back to an optical system, light ray scattering and energy loss are reduced, the light rays can be concentrated, and therefore brightness is improved, and high brightness gain is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of display technology, and in particular to a composite film and a backlight module. BACKGROUND

[0002] With the wide application of liquid crystal display (LCD) technology, the design of the backlight module plays a crucial role in the performance and display effect of the LCD. Since the LCD itself does not have the function of emitting light, it needs to rely on the backlight source to provide light, and the backlight module is the core component to realize this function. The backlight module is usually composed of point light sources and a series of optical materials, including prism sheets, diffusion films, etc. They convert the light emitted by the point light source into a uniform surface light source through the transmission, refraction and scattering of light, thereby improving the display brightness and uniformity.

[0003] At present, the mainstream design of the backlight module adopts the combination of two prism sheets and a diffusion film, which utilizes the refraction characteristics of the prism sheet to converge the light in the horizontal and vertical directions, thereby improving the brightness in the normal direction, increasing the normal brightness and optimizing the display effect. However, the optical structure characteristics of the prism sheet often lead to strong light intensity concentration effect during convergence, which makes the viewing angle range of the display screen become relatively limited, and the brightness may be greatly reduced at different observation angles, thereby affecting the visual experience.

[0004] In addition, the combination of two prism sheets and other optical materials in the traditional design of the backlight module not only increases the optical complexity of the product, but also increases the difficulty of production and assembly. The superposition of each optical material layer may cause changes in optical performance, and in the process of production, the cutting, assembly and alignment of the materials are difficult, which easily leads to low production efficiency and process yield.

[0005] Therefore, how to expand the viewing angle range while ensuring the brightness of the backlight module, and simplify the production process, improve the production efficiency and process yield, has become a technical problem to be solved in the design of the backlight module. CONTENT OF THE INVENTION

[0006] In order to be able to expand the viewing angle range while improving the brightness of the backlight module, and simplify the production process, improve the production efficiency and process yield, the present application provides a composite film and a backlight module.

[0007] The composite film and the backlight module provided by the present application adopt the following technical solutions:

[0008] A composite film comprises a reflective brightness enhancement film layer and a prism layer, the reflective brightness enhancement film layer and the prism layer are connected by a bonding adhesive layer; the prism layer is provided with a plurality of first prism grooves and a plurality of second prism grooves, the plurality of first prism grooves and the plurality of second prism grooves are arranged along a first direction and a second direction respectively, and a plurality of prism structures are formed between the plurality of first prism grooves and the plurality of second prism grooves.

[0009] By adopting the above technical scheme, the first prism grooves and the second prism grooves are designed in the prism layer and arranged along the first direction and the second direction respectively, such a structure can refract light in two directions, thereby greatly expanding the viewing angle range and improving the visual experience; the reflective brightness enhancement film layer has high reflectivity, which can effectively reflect the light emitted from the light source back to the optical system of the backlight module, reduce the scattering and energy loss of the light, and can be directional control to help concentrate the light, thereby improving the brightness and realizing high brightness gain; and the composite film of the present application can simplify the cutting, assembling and alignment process of materials, thereby improving the production efficiency and reducing the production difficulty, and improving the overall production efficiency and process yield.

[0010] In a specific implementable embodiment, the pitch of two adjacent first prism grooves is D1, and the pitch of two adjacent second prism grooves is D2, the D1 is 14-80um, and the D2 is 2-10 times of the D1.

[0011] By adopting the above technical scheme, by making the pitch of the second prism groove 2 to 10 times larger than that of the first prism groove, a more effective bidirectional refraction effect can be produced, a smaller pitch can improve the fineness of the optical effect, and a larger pitch can help a larger light refraction angle, this design not only affects the refraction path of the light, but also effectively adjusts the distribution of the light, thereby optimizing the visual effect and improving the brightness uniformity and viewing angle range of the display screen.

[0012] In a specific implementable embodiment, the longitudinal section of the first prism groove and the longitudinal section of the second prism groove are a triangle or a trapezoid; the top angle of the triangle is 88-92°, and the bottom angle of the trapezoid is 45-50°.

[0013] By adopting the technical scheme, the longitudinal section shape of the triangle enables the light to be concentrated and refracted accurately when passing through the groove, the setting range of the top angle helps to control the propagation direction of the light, the light can be effectively refracted according to the design requirements, and the light is prevented from being excessively dispersed or distorted, thereby expanding the viewing angle range; the longitudinal section of the trapezoid enables the light to be gradually expanded at a certain angle, the setting range of the bottom angle provides a relatively smooth light transition, the refractive effect is more uniform, the abrupt change of the refractive angle is avoided, and the optical effect is improved, thereby expanding the viewing angle range.

[0014] In a specific implementable embodiment, the triangle is an isosceles triangle, and the trapezoid is an isosceles trapezoid.

[0015] By adopting the technical scheme, the design of the isosceles triangle enables the propagation path of the light in the longitudinal section to be symmetrical, ensures that the propagation angles of the light from the top point to both sides are equal, thereby effectively concentrating the light and reducing light scattering or uneven refraction caused by structural asymmetry; the design of the isosceles trapezoid enables the refractive angles of both sides of the trapezoid to be consistent, thereby ensuring that the propagation direction of the light is more uniform, the distribution of the light in different regions is more balanced, and the optical performance is improved.

[0016] In a specific implementable embodiment, the first direction and the second direction are arranged perpendicularly.

[0017] By adopting the technical scheme, the optical structure of the prism layer can refract the light in the horizontal and vertical directions respectively by arranging the first direction and the second direction perpendicularly, thereby effectively expanding the propagation range of the light, optimizing the viewing angle of the display screen, and maintaining good brightness and clarity of the display effect from any direction, and improving the visual effect at different angles.

[0018] In a specific implementable embodiment, the height of the first prism groove is equal to the height of the second prism groove, and the height of the first prism groove and the second prism groove is 7-40 um.

[0019] By adopting the technical scheme, the light is more uniformly guided between the two refractive layers when the height of the first prism groove and the second prism groove is equal, and the height is in the range of 7-40 um, the refraction process of the light is more uniform, thereby improving the viewing angle of the display screen, enabling the user to experience relatively consistent brightness and contrast from different viewing angles, and improving the viewing angle and stability of the display screen.

[0020] In a specific implementable embodiment, the light transmittance of the prism layer is above 90%, and the haze of the prism layer is within 1%.

[0021] By adopting the technical scheme, the design of high light transmittance enables most light to pass through the prism layer, reduces light loss, improves the efficiency of the optical system, and helps to ensure high-quality presentation of picture brightness; low haze indicates that the prism layer has good optical clarity, can effectively avoid light scattering, helps to reduce image blur or distortion caused by surface unevenness, ensures clear and uniform light transmission, and improves display effect.

[0022] In a specific implementation, the reflective brightness enhancement film layer is provided with a matte layer on the side away from the prism layer, and the haze of the matte layer is 5-95%.

[0023] By adopting the technical scheme, the matte layer can diffuse light, making the reflected light through the reflective brightness enhancement film layer more uniform, eliminating light spots and uneven brightness areas, and thus improving the overall brightness uniformity of the display screen; appropriate haze enables the matte layer to effectively scatter light to a certain extent without causing excessive light diffusion, which can reduce direct light concentration and thus prevent visual discomfort caused by excessive reflection.

[0024] A backlight module comprising the composite film as described above.

[0025] In summary, the beneficial technical effects of the present application are:

[0026] 1. In the prism layer design, the first prism groove in the first direction and the second prism groove in the second direction are arranged perpendicularly and form a plurality of prism structures, which can refract light in two directions, thus greatly expanding the viewing angle range and ensuring good brightness and clarity at different angles, avoiding the brightness decay problem of traditional display screens at side viewing angles; and by controlling the reasonable ratio of the first prism groove spacing D1 and the second prism groove spacing D2, more uniform light refraction and distribution are achieved, further improving the brightness uniformity and viewing angle range of the display screen.

[0027] 2. The reflective brightness enhancement film layer can improve the brightness uniformity of the display screen, reduce light scattering and energy loss, and significantly enhance the brightness of the display image by increasing the reflectivity and effectively concentrating light, making the display effect clearer and brighter; and the matte layer on one side of the reflective brightness enhancement film layer can diffuse reflected light, making the brightness more uniform, eliminating light spots and uneven brightness areas, and appropriate haze design ensures that the light will not be excessively scattered, while avoiding excessive light concentration, thus improving the comfort of visual experience. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a three-dimensional diagram for showing the structure of the composite film.

[0029] Figure 2 is a front view for showing the structure of the composite film.

[0030] Figure 3 is an X direction view for showing the structure of the prism layer.

[0031] Figure 4 is a Y direction view for showing the structure of the prism layer.

[0032] BRIEF DESCRIPTION OF DRAWINGS 1, reflective brightness enhancement film layer; 2, prism layer; 3, first prism groove; 4, second prism groove; 5, prism structure; 6, bonding adhesive layer. DETAILED DESCRIPTION

[0033] The following description will be made in conjunction with the accompanying drawings. Figures 1-4 The present application is further described in detail.

[0034] Example One

[0035] Reference Figure 1 and Figure 2 The composite film disclosed in the embodiments of the present application includes but is not limited to a backlight module applied to a display screen; the composite film includes a reflective brightness enhancement film layer 1 and a prism layer 2, and the reflective brightness enhancement film layer 1 and the prism layer 2 are connected by a bonding adhesive layer 6.

[0036] In the embodiments, the reflective brightness enhancement film layer 1 can adopt an existing reflective polarized brightness enhancement film; the reflective polarized brightness enhancement film can effectively improve the polarization state of light, improve the clarity and brightness uniformity of the display screen, so that the reflective brightness enhancement film layer 1 has a high reflectivity, can effectively reflect the light emitted from the light source back to the optical system of the backlight module, reduce the scattering and energy loss of the light, and can be directional controlled to help concentrate the light, thereby improving the brightness and achieving the effect of high brightness gain.

[0037] The prism layer 2 is provided with a plurality of first prism grooves 3 and a plurality of second prism grooves 4, the plurality of first prism grooves 3 and the plurality of second prism grooves 4 are arranged along a first direction and a second direction respectively, and a plurality of convex prism structures 5 are formed between the plurality of first prism grooves 3 and the plurality of second prism grooves 4.

[0038] In the embodiments, the first direction is the X direction, the second direction is the Y direction, and the first direction and the second direction are arranged perpendicularly; the first direction and the second direction are arranged perpendicularly, so that the optical structure of the prism layer 2 can refract the light in the horizontal and vertical directions respectively, thereby effectively expanding the propagation range of the light and optimizing the viewing angle of the display screen, so that good brightness and clarity can be maintained at different viewing angles and the visual effect at different angles can be improved.

[0039] Reference Figure 3 andFigure 4 In the embodiment, the interval between two adjacent first prism grooves 3 is D1, and the interval between two adjacent second prism grooves 4 is D2, D1 is 14-80 um, and D2 is an integer multiple of 2-10 times of D1. In the embodiment, preferably, D2=2D1. This design not only makes the light refraction effect more uniform, but also effectively controls the distribution and refraction angle of light, thereby improving the brightness uniformity and viewing angle range of the display screen.

[0040] By designing the interval of the second prism groove 4 to be 2-10 times larger than that of the first prism groove 3, a more effective bidirectional refraction effect can be produced. A smaller interval can improve the fineness of the optical effect, while a larger interval helps to achieve a larger light refraction angle. This design not only affects the refraction path of light, but also effectively adjusts the distribution of light, thereby optimizing the visual effect and improving the brightness uniformity and viewing angle range of the display screen.

[0041] The longitudinal section of the first prism groove 3 and the longitudinal section of the second prism groove 4 are a triangle or a trapezoid, the triangle is an isosceles triangle, and the trapezoid is an isosceles trapezoid.

[0042] The top angle of the triangle is 88°-92°, and the bottom angle of the trapezoid is 45°-50°. In the embodiment, preferably, the longitudinal section of the first prism groove 3 and the longitudinal section of the second prism groove 4 are an isosceles triangle with a top angle of 88°-92°. The design of the isosceles triangle makes the propagation path of light in the longitudinal section symmetrical, ensuring that the propagation angles of light from the apex to both sides are equal, thereby effectively concentrating light and reducing light scattering or uneven refraction caused by structural asymmetry. The setting range of the top angle helps to control the propagation direction of light, enabling the light to be effectively refracted according to the design requirements and avoiding excessive dispersion or distortion of the light, thereby improving the optical effect and expanding the viewing angle range.

[0043] Referring to Figure 1 and Figure 2 , in order to further optimize the optical effect, the height of the first prism groove 3 is equal to the height of the second prism groove 4, and the height of the first prism groove 3 and the second prism groove 4 is 7 um-40 um. By designing the height of the first prism groove 3 and the second prism groove 4 to be equal, the guidance of light between the two refraction structures is more uniform. And by designing the height to be in the range of 7 um-40 um, the light refraction process will be more uniform, thereby improving the viewing angle of the display screen, so that users can experience relatively consistent brightness and contrast from different viewing angles, while improving the viewing angle and stability of the display screen.

[0044] In terms of material selection, the material of the prism layer 2 is one of polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMPM). In this embodiment, the material of the prism layer 2 is preferably polyethylene terephthalate (PET). PET material has good light transmission, can effectively conduct light and reduce light loss, and its high transparency and low scattering performance can ensure the guiding and refracting effect of light, improving the clarity and brightness uniformity of the display effect. Moreover, PET material has good processing performance and can be accurately formed through processes such as hot pressing and injection molding to produce complex prism structures 5.

[0045] In terms of optical performance of the prism layer 2, the light transmittance of the prism layer 2 is above 90%. Through the design of high light transmittance, most of the light can pass through the prism layer 2, reducing light loss and improving the efficiency of the optical system, which helps to ensure the high-quality presentation of picture brightness.

[0046] The haze of the prism layer 2 is within 1%. Through the design of low haze, the prism layer 2 can have good optical clarity, effectively avoiding light scattering, which helps to reduce image blur or distortion caused by surface unevenness, ensuring clear and uniform light transmission and improving the display effect.

[0047] The side of the reflective brightness enhancement film layer 1 away from the prism layer 2 is provided with a matte layer, and the haze of the matte layer is 5-95%. In this embodiment, the haze of the matte layer is preferably 13%. The matte layer can diffuse light, making the light reflected by the reflective brightness enhancement film layer 1 more uniform, eliminating light spots and uneven brightness areas, thereby improving the overall brightness uniformity of the display screen. Appropriate haze allows the matte layer to effectively scatter light to some extent without causing excessive light diffusion, which can reduce direct light concentration and prevent visual discomfort caused by excessive reflection, thereby optimizing the visual experience.

[0048] Through the above design scheme, the composite film provided in this embodiment can effectively improve the brightness uniformity, viewing angle, and optical effect of the display screen. The bidirectional refractive prism structure 5 of the composite film, combined with the design of high light transmittance and low haze, ensures that the visual effect of the display screen remains clear and bright even at different angles, and eliminates visual interference caused by light spots and uneven brightness. The application of the composite film of the present application will greatly improve the optical performance of the backlight module, thereby realizing high-quality display effect and meeting the market demand for high brightness and wide viewing angle.

[0049] The composite film is not only suitable for traditional liquid crystal display screens (LCD), but also can be applied to OLED display screens, electronic tags, and other display technologies, and has wide market application prospects.

[0050] In order to verify the advantages of the composite film of the present application in practical application, a targeted experimental scheme is designed, and the experimental purpose is to show the performance improvement of the composite film of the present application compared with the traditional film layer in the backlight module of the display device by measuring various performance indicators of the material, as shown in the following table:

[0051]

[0052] As can be seen from the table, the composite film of the present scheme has obvious superiority in multiple technical indicators, which is specifically as follows:

[0053] Total thickness of the material: the thickness of the material of the present scheme is 0.2mm, which is half of the 0.4mm of the comparative scheme, which means that the present scheme can provide a thinner and lighter film layer, which helps to improve the overall thinness of the display device and meet the market demand for high-performance and thin display products.

[0054] Viewing angle: the viewing angle of the present scheme is 67°, which is higher than the 64° of the comparative scheme, and the increased viewing angle can effectively improve the display effect of the display device under different observation angles and enhance the viewing experience of the user under different viewing angles.

[0055] Shielding value: the shielding value of the present scheme is 0.25, which is significantly higher than the 0.15 of the comparative scheme, which means that the present scheme can effectively reduce the loss of light and improve the overall optical performance, and the increase of the shielding value means that the light loss is less and the external light interference can be effectively controlled.

[0056] Adsorption: in the present scheme, the adsorption phenomenon has been eliminated (“none”), while the comparative scheme has slight adsorption, which helps to avoid unnecessary adhesion of the film layer during assembly or use, further improving the quality and ease of use of the product.

[0057] Single sheet stiffness: the single sheet stiffness of the present scheme is 40, which is higher than the 25 of the comparative scheme, which means that the composite film is more stable during use and is not easily deformed by external force, which enhances the extrusion resistance and compression resistance of the film layer and improves the overall service life.

[0058] Cutting / assembly times: the cutting and assembly times of the present scheme are 2 times / 2 times, which are less than the 3 times / 3 times of the comparative scheme; the reduction of cutting and assembly times helps to improve production efficiency, reduce production cost, and reduce defects in the production process, thereby improving the yield.

[0059] Optical gain: the optical gain of the present scheme is 133%, which is significantly higher than the 100% of the comparative scheme; this indicates that the composite film of the present application can effectively improve the performance of the display device in terms of brightness, light uniformity, diffusion effect, etc., and provide a better visual experience.

[0060] Through the analysis of the performance indicators of the composite film of the present application, it can be concluded that the film has obvious technical advantages in multiple key areas compared to traditional comparative schemes, especially in the aspects of material thinning, viewing angle expansion, optical gain, production efficiency, etc. The composite film of the present application has stronger market competitiveness, meets the needs of modern display devices for high efficiency, thinness, and high-quality display effect. In addition, the improvement of the stability of the film layer and the production efficiency also provides more efficient and low-cost production solutions for manufacturers.

[0061] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application. Therefore, any equivalent changes made on the basis of the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A composite film, characterized by: The composite film comprises a reflective brightness enhancement film layer (1) and a prism layer (2), the reflective brightness enhancement film layer (1) and the prism layer (2) are connected by a bonding adhesive layer (6); the prism layer (2) is provided with a plurality of first prism grooves (3) and a plurality of second prism grooves (4), the plurality of first prism grooves (3) and the plurality of second prism grooves (4) are arranged along a first direction and a second direction respectively, and a plurality of prism structures (5) are formed between the plurality of first prism grooves (3) and the plurality of second prism grooves (4).

2. The composite film of claim 1, wherein: The distance between two adjacent first prism grooves (3) is D1, and the distance between two adjacent second prism grooves (4) is D2, the D1 is 14-80um, and the D2 is 2-10 times of the D1.

3. The composite film of claim 1, wherein: The longitudinal section of the first prism groove (3) and the longitudinal section of the second prism groove (4) are a triangle or a trapezoid; the top angle of the triangle is 88-92°, and the bottom angle of the trapezoid is 45-50°.

4. The composite film of claim 3, wherein: The triangle is an isosceles triangle, and the trapezoid is an isosceles trapezoid.

5. The composite film of claim 1, wherein: The first direction and the second direction are perpendicular.

6. The composite film of claim 1, wherein: The height of the first prism groove (3) is equal to the height of the second prism groove (4), and the height of the first prism groove (3) and the second prism groove (4) is 7-40um.

7. The composite film of claim 1, wherein: The light transmittance of the prism layer (2) is above 90%, and the haze of the prism layer (2) is within 1%.

8. The composite film of claim 1, wherein: The side of the reflective brightness enhancement film layer (1) away from the prism layer (2) is provided with a haze layer, and the haze of the haze layer is 5-95%.

9. A backlight module, characterized in that: The composite film comprises the composite film according to any one of claims 1-8.

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