Composite optical film and backlight module

Abstract

The utility model relates to a composite optical film and a backlight module applying the same, two or more prism layers are arranged on a light emitting surface of the composite optical film, and prisms in at least two prism layers are arranged in different directions so as to realize multi-directional light refraction and guidance. The prism layer is divided into three continuous areas: a first atomization prism area, a common prism area and a second atomization prism area. In the first atomization prism area and the second atomization prism area, the surfaces of the prisms comprise microstructures, the haze of the two areas is improved, and glare can be reduced. The first atomization prism area is located in the lamp socket area of the composite optical film, and the second atomization prism area is located in the tail area, so that light rays are softer and more uniform in a specific area, and the shielding performance and the hotspot and sky side bright line prevention capacity of a product are effectively improved. The utility model further provides a backlight module comprising the composite optical film, a high-efficiency light guide plate and a side-in type light source, and the problems that a lamp socket at the light-in position of electronic equipment is poor in shielding performance, and hotspot in front of a lamp and a sky side bright line are poor can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of optical films, and in particular to a composite optical film and a backlight module. Background Art

[0002] With the rapid development of mobile phones and LCD display technology, consumers' demands for display quality are increasing. This has not only driven continuous innovation in display technology, but also prompted the continuous evolution of backlight module design to meet the demand for a higher standard of visual experience. In particular, with the trend towards thinner and lighter mobile devices, the use of edge-lit LED light sources has become increasingly widespread. However, this design approach also introduces the problem of uneven bright spots around the edges, the so-called "hotspot" phenomenon, which significantly affects the uniformity and overall quality of the display.

[0003] To address this challenge, various shading components are now being incorporated into backlight module designs to reduce light leakage from the light source side and hotspots at the edges. However, this approach also introduces new problems. On the one hand, the addition of shading components increases the width of the ineffective area at the edge of the display, which not only increases manufacturing costs but also limits the effective utilization of the display area, negatively impacting display quality. On the other hand, existing optical film material designs primarily focus on improving brightness and achieving light uniformity, addressing these two issues through brightening films and diffusion films, respectively. However, targeted designs for light leakage from the light source side and hotspots are relatively lacking.

[0004] Specifically, current film designs offer suboptimal shielding at the light entrance, resulting in a significant hotspot phenomenon in front of the lamp. To alleviate this problem, the industry has experimented with solutions such as light-shielding tape, silk-screened diffuser film borders, and small reflective sheets at the lamp base. While these measures can mitigate the firefly effect and tail light line at the lamp base to a certain extent, they also increase manufacturing costs, hindering product cost control and improving market competitiveness.

[0005] Furthermore, as a key component in backlight modules, the light guide plate (LGP) exhibits higher brightness in areas where light rays intersect, while lower brightness in areas where they do not intersect. This uneven brightness distribution is a major cause of the hotspot phenomenon. Therefore, effectively improving the brightness distribution on the LGP and reducing the hotspot phenomenon without incurring additional costs has become a key issue in current backlight module design. Utility Model Content

[0006] The purpose of this application is to provide a composite optical film that can address the problems of poor light shielding performance at the light entrance of mobile phones, PADs, and laptops, as well as the high hotspot and high skylight lines. This film improves the optical uniformity of the light-emitting surface and tail of the product at the light entrance, and enhances the product's shielding performance, hotspot protection, and skylight line protection. This objective is achieved through the following technical solution: the composite optical film includes two or more prism layers disposed on the light exit surface, each prism layer including a prism array, with the prisms in at least two prism layers having different arrangement directions.

[0007] At least one or all of the prism layers include a first fogged prism area, a normal prism area, and a second fogged prism area arranged in sequence, wherein the prism surfaces of the first fogged prism area and the second fogged prism area have a surface microstructure, and the haze of the first fogged prism area and the second fogged prism area is greater than the haze of the normal prism area;

[0008] The first fogged prism area in each prism layer is located in the lamp mouth area of ​​the composite optical film, and the second fogged prism area in each prism layer is located in the tail area of ​​the composite optical film.

[0009] In one embodiment, the haze of the first fogged prism area and the second fogged prism area is 90% to 100%.

[0010] In one embodiment, each prism layer includes a substrate layer on a side opposite to the light emitting surface.

[0011] In one embodiment, a back coating layer is further included, and the back coating layer is disposed on the surface of the bottom substrate layer opposite to the prism layer.

[0012] In one embodiment, the areas of the first atomized prism region and the second atomized prism region are respectively within a range of 5%-15% of the area of ​​the prism layer.

[0013] In one embodiment, an atomized bonding layer is further included between the prism layer and the upper substrate layer.

[0014] In one embodiment, the angle between the arrangement directions of the prisms in at least two prism layers is in the range of 80°-100°.

[0015] In one embodiment, the angle between the arrangement directions of the prisms in at least two prism layers is 90°.

[0016] In addition, the present application also provides a backlight module, including the aforementioned composite optical film, a light guide plate and a light source.

[0017] In one embodiment, the light source is an edge-lit light source.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] The composite optical film of this application achieves multi-angle refraction and scattering of light by disposing two or more prism layers on the light-emitting surface, with the prisms in at least two prism layers arranged in different directions, thereby improving the uniform distribution of light on the light-emitting surface. When a light source enters the light guide plate from the side light-incident surface, the light passes through the first atomized prism area, the ordinary prism area, and the second atomized prism area in sequence. This multi-layered, multi-directional prism design not only improves the shielding of the lamp mouth and tail, but also ensures a high degree of optical uniformity on the light-emitting surface, thereby enhancing the quality of the displayed image.

[0020] Secondly, the prism surfaces in the first and second atomized prism areas have surface microstructures, resulting in a much higher haze in these two areas than in ordinary prism areas. Specifically, when the haze of the first and second atomized prism areas is set to 90%-100%, the high haze design enhances image blur in the lamp mouth and tail areas, effectively reducing the firefly effect at the edges of the luminous surface and achieving high overall image uniformity.

[0021] In addition, the composite optical film of the present application also includes structures such as a substrate layer, a back coating layer, and a fogging bonding layer. These structures work together on the prism layer to further enhance the product's shielding properties, anti-hotspot and sky-side bright line capabilities. In particular, the design of the back coating layer, whose haze is in the range of 2% to 20%, can not only maintain a certain light transmittance, but also enhance the scattering effect of light, thereby further improving the uniformity of the display image. When the composite optical film of the present application is applied to a backlight module, especially when used in conjunction with a side-entry light source, the shielding properties and optical uniformity are fully reflected. In summary, the composite optical film and backlight module of the present application achieve efficient utilization of light sources and uniform distribution of light, thereby improving the quality of the display image. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a composite optical film in one embodiment of the present application;

[0023] Figure 2 Schematic diagram of the structure of a prism layer in a composite optical film in one embodiment of the present application;

[0024] Figure 3 is a schematic structural diagram of another prism layer in a composite optical film in one embodiment of the present application;

[0025] Figure 4 It is a structural schematic diagram of a backlight module including the composite optical film of the present application.

[0026] Explanation of the accompanying reference numerals: 100, prism layer; 110, first atomized prism area; 120, ordinary prism area; 130, second atomized prism area; 200, substrate layer; 300, back coating layer; 400, atomized bonding layer; 500, light guide plate; 600, light source. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] As a key part of the backlight module, the composite optical film undertakes multiple tasks such as regulating light, improving picture uniformity, and reducing adverse optical phenomena. The backlight module is the light source system behind the liquid crystal display panel, and its design is directly related to indicators such as brightness, contrast and color saturation of the display. With the growing market demand for thinness and lightness, some problems in the design of traditional backlight modules have gradually become prominent, such as poor lamp shielding performance at the light entrance, hotspot phenomenon in front of the lamp, and poor bright lines on the sky side. These problems not only affect the aesthetics of the display, but also increase manufacturing costs and limit the market competitiveness of the product. In order to solve the above problems, this application will elaborate on a new composite optical film and backlight module design. This design uses a unique prism layer structure, a high haze shielding area and multi-level optical control means to achieve efficient use of light and high uniformity of the picture, which not only significantly improves the quality of the display, but also reduces manufacturing costs. Next, the specific technical features, working principles and beneficial effects of this design will be discussed one by one. Please refer to Figures 1 to 3 As shown, a composite optical film in a preferred embodiment of the present application includes two or more prism layers 100 arranged on a light-emitting surface, wherein the prism layer 100 includes a prism array, and the prisms in at least two prism layers 100 are arranged in different directions. At least one layer or all of the prism layers 100 include a first fogged prism area 110, an ordinary prism area 120, and a second fogged prism area 130 arranged in sequence. The prism surfaces in the first fogged prism area 110 and the second fogged prism area 130 have a surface microstructure, and the haze of the first fogged prism area 110 and the second fogged prism area 130 is greater than the haze of the ordinary prism area 120. The first fogged prism area 110 in each prism layer 100 is located in the lamp mouth area of ​​the composite optical film, and the second fogged prism area 130 in each prism layer 100 is located in the tail area of ​​the composite optical film.

[0031] The composite optical film structure consists of two or more prism layers 100 disposed on the light-emitting surface. These prism layers 100 include a prism array. The prisms in at least two prism layers 100 are arranged in different directions, achieving a more uniform light distribution through multi-directional light refraction and guidance. At least one or all prism layers 100 are innovatively divided into three continuous regions: a first hazy prism region 110, a normal prism region 120, and a second hazy prism region 130. Within the first hazy prism region 110 and the second hazy prism region 130, the prism surfaces include microstructures that scatter light, increasing the haze of these two regions. Compared to the normal prism region 120, their haze values ​​are higher. The increased haze helps reduce glare and improve visual comfort, especially in high-brightness environments. It also effectively balances the relationship between brightness and viewing angle, making the light softer and more uniform within a specific area. The first hazy prism area 110 in each prism layer 100 is positioned at the light-entry area of ​​the composite optical film, where light initially enters. The second hazy prism area 130 in each prism layer 100 is located at the rear end of the composite optical film. This area corresponds to the opposite side of the prism layer 100 from the initial light input location, helping to maintain soft and uniform light in both areas. This improves optical uniformity at both the light-entry surface and the rear end of the product, enhancing the product's shielding, hotspot protection, and skylight line protection capabilities.

[0032] Specifically, the haze of the first and second hazy prism regions 110 and 130 is between 90% and 100%. When the haze reaches 90% to 100%, the microstructure on the prism surface can scatter most of the light, making the light distribution more even within the lamp mouth and tail areas, effectively avoiding the problem of excessive concentration or loss of light in local areas. This makes the first and second hazy prism regions 110 and 130 visually appear blurred. This blurring helps reduce or eliminate direct light projection into these areas, thereby effectively shielding the lamp mouth and tail areas.

[0033] Specifically, each prism layer 100 includes a substrate layer 200 on the side opposite to the light-emitting surface. In the structural design of the composite optical film, each prism layer 100 is configured with a substrate layer 200 on the side opposite to the light-emitting surface. This substrate layer 200 not only provides support for the prism layer 100, but also ensures the stability and durability of the prism structure.

[0034] Specifically, it also includes a back coating 300, which is arranged on the surface of the bottom substrate layer 200 opposite to the prism layer 100. The back coating 300 is arranged at the bottom of the entire structure, that is, it directly covers the other side surface of the substrate layer 200 opposite to the prism layer 100. The addition of the back coating 300 improves the overall durability and protection, and can effectively prevent moisture or impurities in the external environment from directly contacting the substrate layer 200, thereby extending the service life of the entire optical component. The back coating 300 may also have a certain scratch resistance to further protect the upper structure. The back coating 300 can be used as a reflective layer or an anti-reflective layer to adjust the reflection or transmission characteristics of light according to specific needs and optimize the utilization efficiency of light. For example, in some applications, the back coating 300 can be designed as a high-reflectivity material to reflect light that is not effectively utilized by the prism layer 100 back to the prism layer 100, thereby improving the secondary utilization rate of light.

[0035] Specifically, the areas of the first fogged prism area 110 and the second fogged prism area 130 are respectively in the range of 5%-15% of the area of ​​the prism layer 100. By adjusting the area of ​​the first fogged prism area 110 and the second fogged prism area 130, the effect of setting the fogged area on the brightness can be minimized while reducing glare. Furthermore, the thickness of the substrate layer 200 is in the range of 25~300μm, and the haze of the back coating layer 300 is in the range of 2%~20%. The selection of the thickness range achieves a balance between structural strength and optical performance. The thinner substrate layer 200 can reduce the scattering and absorption of light and improve the transmittance of light, but at the same time it is also necessary to ensure sufficient mechanical strength to support the upper structure and prevent deformation or breakage. Therefore, the thickness range of 25 to 300μm can meet the needs of lightweight and thinness while ensuring the stability and durability of the structure. At the same time, the haze of the back coating layer 300 is controlled within the range of 2% to 20%. By selecting the visual clarity and light transmittance of the material and adjusting the haze of the back coating layer 300 within this range, a variety of optical effects can be achieved.

[0036] Specifically, an atomized bonding layer 400 is also included between the prism layer 100 and the upper substrate layer 200. The atomized bonding layer 400 not only plays a role of connection and fixation, but also can scatter light to a certain extent through its unique microstructure or chemical composition, thereby achieving uniform distribution and soft transition of light. While maintaining a certain light transmittance, it can reduce the glare caused by direct light exposure and improve visual comfort. In addition, the atomized bonding layer 400 can also effectively reduce the reflection and interference of light on the interface, reduce glare and ghosting phenomena, and further improve the clarity and contrast of the image.

[0037] Specifically, the angle between the prisms in at least two prism layers 100 is within a range of 80°-100°. By setting the angle within this specific range, the refraction and reflection paths of light between the multiple prism layers 100 can be effectively controlled. When light passes from one prism layer 100 to another, the angle between the prisms is close to a right angle (90°), causing it to undergo more significant refraction, leading to more efficient guidance in the desired direction. This helps reduce light loss at the interlayer interfaces, improves light utilization, and ultimately enhances the brightness and contrast of the entire optical assembly. Furthermore, the angle design of the prisms in the multiple prism layers 100 also facilitates light guidance over a wider viewing angle. Because light undergoes multiple refractions and reflections between the multiple prism layers 100, its propagation direction is continuously adjusted and optimized, thereby providing uniform brightness and color rendering over a wider viewing angle range. In a further preferred embodiment, the angle between the prisms in at least two prism layers 100 is 90°.

[0038] See also Figure 4 , Figure 4 : This is a structural diagram of a backlight module including the composite optical film of the present application. In addition, the present application also provides a backlight module including the aforementioned composite optical film, a light guide plate 500 and a light source 600. As one of the core components of the backlight module, the composite optical film includes a substrate layer 200, a prism layer 100, and a possible back coating layer 300 and an atomized bonding layer 400, which work together to achieve efficient guidance and distribution of light. The arrangement and multi-layer design of the prism layer 100 ensure that the light can be uniformly irradiated out of the module at the most ideal angle and distribution after undergoing multiple refractions and reflections inside the module. Secondly, the efficient light guide plate 500, as a light transmission medium, can effectively guide the light emitted by the light source 600 to the entire module, reduce light loss, and improve light utilization efficiency. The close fit between the light guide plate 500 and the composite optical film ensures the continuity and consistency of the light during transmission, thereby improving the overall performance of the backlight module. The Light Source 600 system provides the backlight unit with light source input. Parameters such as brightness, color temperature, and spectral distribution of the Light Source 600 are carefully tuned to ensure optimal optical performance, matching the performance of the composite optical film and light guide plate 500. This backlight unit design not only improves light efficiency and brightness uniformity, but also offers high flexibility and adaptability, enhancing the product's shielding, hotspot protection, and skylight line protection.

[0039] Specifically, the light source 600 is an edge-lit light source 600. In terms of structural layout, the edge-lit light source 600 places the light source 600 components on the side of the backlight module, and distributes light evenly throughout the module through the guidance of the light guide plate 500. This design not only reduces the number and volume of light source 600 components, lowering the overall weight and cost of the module, but also makes the module more compact and flexible in structural design.

[0040] As can be seen from the foregoing, the present application proposes a new composite optical film and a backlight module for its application. The core design of the composite optical film lies in the two or more prism layers provided on its light-emitting surface, and the prisms in at least two prism layers are arranged in different directions. The prism layer is divided into three continuous areas: a first fogged prism area, a normal prism area, and a second fogged prism area. In the first and second fogged prism areas, the prism surfaces contain microstructures. These microstructures increase the haze of these two areas by scattering light. Compared with the normal prism area, the haze is higher, which helps to reduce glare and improve visual comfort. In particular, the first fogged prism area is located in the lamp mouth area of ​​the composite optical film, while the second fogged prism area is located in the tail area. This design makes the light softer and more uniform in a specific area, effectively improving the product's shielding properties, anti-hotspot and sky-side bright line capabilities.

[0041] In addition, the composite optical film also includes a substrate layer, a back coating layer, and a possible atomized bonding layer. The substrate layer provides support for the prism layer and ensures the stability of the structure. The back coating layer is located on the bottom substrate layer, providing additional durability and protection, and may serve as a reflective layer or anti-transmittance layer to optimize light utilization efficiency; the atomized bonding layer is located between the prism layer and the upper substrate layer, and achieves uniform distribution and soft transition of light by scattering light. In the design of the prism layer, the angle between the prism arrangement directions in at least two prism layers is precisely controlled within the range of 80° to 100°. This design helps to reduce the loss of light at the interface between the layers, improve the utilization of light, and enhance the brightness and contrast of the entire optical component.

[0042] The present application also provides a backlight module comprising the above-mentioned composite optical film, an efficient light guide plate and an edge-entry light source. The design of the edge-entry light source not only reduces the number and volume of light source components, reduces the overall weight and cost of the module, but also makes the module more compact and flexible in structural design. The backlight module achieves efficient transmission and distribution of light through the close cooperation between the composite optical film and the light guide plate, further improving the brightness uniformity and visual performance. In summary, the composite optical film and its backlight module design of the present application have better technical effects in optimizing light distribution, improving visual comfort, enhancing light utilization efficiency and reducing energy consumption.

[0043] 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. A composite optical film, characterized in that: It comprises two or more prism layers (100) arranged on a light-emitting surface, wherein the prism layers (100) comprise a prism array, and the prisms in at least two prism layers (100) are arranged in different directions; At least one layer or all of the prism layers (100) include a first fogged prism area (110), a normal prism area (120), and a second fogged prism area (130) arranged in sequence, the prism surfaces of the first fogged prism area (110) and the second fogged prism area (130) having a surface microstructure, and the haze of the first fogged prism area (110) and the second fogged prism area (130) is greater than the haze of the normal prism area (120); The first fogged prism area (110) in each prism layer (100) is located in the lamp mouth area of ​​the composite optical film, and the second fogged prism area (130) in each prism layer (100) is located in the tail area of ​​the composite optical film.

2. The composite optical film according to claim 1, wherein: The haze of the first atomized prism area (110) and the second atomized prism area (130) is 90% to 100%.

3. The composite optical film according to claim 1, wherein: Each prism layer (100) comprises a substrate layer (200) on a side opposite to the light-emitting surface.

4. The composite optical film according to claim 3, wherein: It also includes a back coating layer (300), wherein the back coating layer (300) is arranged on the surface of the bottom substrate layer (200) opposite to the prism layer (100).

5. The composite optical film according to claim 1, wherein: The areas of the first atomized prism region (110) and the second atomized prism region (130) are respectively within the range of 5%-15% of the area of ​​the prism layer (100).

6. The composite optical film according to claim 3, wherein: An atomized bonding layer (400) is further included between the prism layer (100) and the upper substrate layer (200).

7. The composite optical film according to claim 1, wherein: The angle between the prism arrangement directions in at least two prism layers (100) is within the range of 80°-100°.

8. The composite optical film according to claim 7, wherein: The angle between the prism arrangement directions in at least two prism layers (100) is 90°.

9. A backlight module, characterized in that: It comprises the composite optical film according to any one of claims 1 to 8, a light guide plate (500) and a light source (600).

10. The backlight module according to claim 9, wherein: The light source (600) is an edge-entry light source (600).

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