Composite brightness enhancement film and manufacturing method thereof

Abstract

The invention relates to a composite brightness enhancement film and a manufacturing method thereof, and relates to the technical field of optics, and the composite brightness enhancement film comprises a first brightness enhancement film which comprises a first prism layer and a first substrate which are stacked; the second brightness enhancement film comprises a second prism layer and a second base material which are stacked; the first base material and the second prism layer are connected through the attaching layer; the protective layer is arranged between the first base material and the laminating layer, and the protective layer is used for absorbing ultraviolet light. By introducing the protective layer to optimize the structural design of the film, the protective layer can effectively absorb ultraviolet light, the ultraviolet light is prevented from excessively irradiating the Primer coating of the first base material, and the degradation and failure risks of the Primer coating are reduced, so that the adhesive force between the first prism layer and the first base material in the production process is improved, and the production efficiency is improved. Furthermore, the stability and the performance of the brightness enhancement film are improved, the brightness enhancement effect of the film can be effectively improved, and the durability and the mechanical strength of the film are improved.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a composite brightness enhancement film and a manufacturing method thereof. Background Art

[0002] Brightness enhancement film is widely used in backlight modules to effectively focus the light emitted by the light source. Especially in display devices such as monitors, brightness enhancement film can increase the display brightness, thereby achieving the goal of reducing the energy consumption of the display. Brightness enhancement film is usually made of transparent resin material, including a substrate and a focusing prism structure on the surface of the substrate. The focusing prism structure is usually composed of multiple parallel prism strips to form a prism array. The prism array refraction and reflection of light redirects the light originally emitted outside the observer's field of view into the observer's field of view, thereby improving the utilization rate of the light energy of the light source and improving the brightness.

[0003] As the display industry's demand for thinner products continues to increase, the traditional backlight module structure consisting of two diffusion films and two brightness enhancement films has become too thick and heavy. In addition, when light passes through the diffusion film, there will be a large light loss, which seriously affects the backlight brightness and increases the light energy consumption. Therefore, the industry has improved the brightness enhancement film and developed a composite brightness enhancement film. With its thinness and high efficiency, the composite brightness enhancement film has gradually occupied an increasing share in the market.

[0004] The focusing prism structure layer in the brightness enhancement film usually adopts UV resin coating. However, the adhesion of UV coating is weak, which often becomes the main reason affecting the production quality. At present, the optical film industry often uses corona treatment or adding Primer coating to increase the surface tension of the film in order to enhance the adhesion of UV coating to the substrate. Although corona treatment can increase the surface tension, its effect is unstable and short-lived. Therefore, the industry generally uses film materials with Primer coating to improve adhesion.

[0005] In the production process of composite brightness enhancement film, due to the numerous process steps, the Primer coating on the substrate surface needs to be irradiated with UV lamps or LED lamps of different energies for many times. Excessive exposure will cause different degrees of damage to the Primer coating, thereby reducing the surface energy of the film substrate, affecting the adhesion of the subsequent UV resin coating, resulting in poor production and affecting the yield. Summary of the invention

[0006] In order to solve the problem of Primer coating failure during the production process, the present application provides a composite brightness enhancement film and a method for manufacturing the same.

[0007] The present application provides a composite brightness enhancement film and a method for manufacturing the same, which adopts the following technical solutions: A composite brightness enhancement film comprises: a first brightness enhancement film, comprising a first prism layer and a first substrate stacked in layers; The second brightness enhancement film comprises a second prism layer and a second substrate which are stacked; A bonding layer, wherein the first substrate and the second prism layer are connected by the bonding layer; A protective layer is disposed between the first substrate and the laminating layer, and is used for absorbing ultraviolet light.

[0008] By adopting the above technical solution, a protective layer is designed between the first substrate and the bonding layer. The protective layer can effectively absorb ultraviolet light, avoid excessive exposure of ultraviolet light to the Primer coating of the first substrate, reduce the risk of degradation and failure of the coating, thereby improving the adhesion between the first prism layer and the first substrate in the production process, and then improving the stability and performance of the brightness enhancement film; the composite brightness enhancement film of the present application adopts a multi-layer structure design, and both brightening films adopt a prism array structure, which increases the utilization rate of light by refracting and reflecting light, ensuring efficient light transmission and brightness improvement of the backlight module; at the same time, by absorbing ultraviolet light through the designed protective layer, not only can the stability of the coating be protected, but also the overall optical performance of the composite brightening film is optimized, thereby improving the high brightness and high efficiency of the backlight module.

[0009] In a specific possible implementation manner, the protective layer is used to absorb excess ultraviolet light when the bonding layer is cured with ultraviolet light, and the absorption rate of the protective layer to the excess ultraviolet light is 98% or more.

[0010] By adopting the above technical scheme, the above parameters show that excess ultraviolet light during curing can be effectively blocked or absorbed by the protective layer 6, while also ensuring the curing effect of the bonding layer 2 during the bonding process, reducing the transmission of excess ultraviolet light to optical elements, avoiding potential damage to other optical materials by excess ultraviolet light, and ensuring long-term stability and reliability.

[0011] In a specific embodiment, the material of the protective layer includes resin and light stabilizing agent.

[0012] In a specific embodiment, the light stabilizing agent includes an ultraviolet absorber and an antioxidant.

[0013] By adopting the above technical solution, the combination of UV absorbers and antioxidants as light stabilizing agents can effectively delay the damage of UV rays and oxidation to coatings and substrates, enhance the weather resistance and anti-aging ability of materials, thereby improving the overall long-term stability and optical properties, extending service life, reducing maintenance costs, and improving economic benefits.

[0014] In a specific embodiment, the ultraviolet absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405; the antioxidant is one or more of RIANOX1135R and RIANOX1520.

[0015] By adopting the above technical solution and using the combination of RIASORBUV series ultraviolet absorbers and RIANOX series antioxidants, the ultraviolet absorption capacity and antioxidant performance of the protective layer can be greatly improved, its service life can be extended, long-term stability can be maintained, and excessive exposure of ultraviolet light to the Primer coating of the first substrate can be effectively avoided, further reducing the degradation and failure risk of the Primer coating.

[0016] In a specific embodiment, the resin is an acrylic resin.

[0017] By adopting the above technical solution, acrylic resin has good weather resistance, can maintain stable performance when exposed to ultraviolet rays for a long time, reduce material aging, color fading and embrittlement caused by ultraviolet rays, and ensure the effect of the protective layer absorbing ultraviolet light; and acrylic resin has high transparency, and the protective layer can provide a clear and transparent appearance while achieving the effect of absorbing ultraviolet light.

[0018] In a specific embodiment, the thickness of the protective layer is 0.5 um-20 um.

[0019] By adopting the above technical solution, the thickness of the protective layer directly affects its ability to absorb ultraviolet light. A thinner protective layer cannot fully absorb ultraviolet light, while an overly thick protective layer will experience absorption saturation and cannot significantly improve the absorption effect. The appropriate thickness of the protective layer can effectively protect the optical system or material and prevent excessive ultraviolet light from penetrating. While ensuring efficient absorption of ultraviolet light, it avoids waste of resources or additional costs caused by excessive thickness.

[0020] A method for making the composite brightness enhancement film as described above, the method comprising the following steps: S1. providing a first substrate, forming a protective layer on the first substrate, and then forming a bonding layer on a side of the protective layer away from the first substrate; S2, providing a second substrate, and manufacturing a second prism layer on the second substrate to obtain a second incremental film; S3, extrusion-bonding the bonding layer obtained in S1 and the second prism layer obtained in S2, and irradiating them with ultraviolet light, so that the bonding layer and the second prism layer are cured and bonded together, to obtain a semi-finished optical film; S4. Making a first prism layer on a side of the first substrate away from the protective layer to obtain a first brightness enhancement film, thereby completing the production of the composite brightness enhancement film.

[0021] By adopting the above technical scheme, a protective layer is added between the composite brightness enhancement film layers, and the protective layer can absorb ultraviolet light, thereby preventing ultraviolet light from directly irradiating the first substrate, avoiding failure of the Primer coating in the first substrate, thereby improving the adhesion between the first prism layer and the first substrate, so that the subsequent first prism layer and the first substrate can be stably connected, while optimizing the ultraviolet light curing process, protecting the first substrate, enhancing the optical performance, and improving the production process and product stability; the method for preparing the composite brightness enhancement film can effectively improve the brightening effect of the optical film, improve the durability and mechanical strength of the film, and ensure the production efficiency and stability of the film performance by optimizing the film structure design, combining ultraviolet light curing technology and precise bonding technology.

[0022] In a specific embodiment, the material of the protective layer includes the following components by weight: acrylic resin, 98.5%-99.6%; light stabilizing agent, 0.4%-1.5%.

[0023] By adopting the above technical scheme, a high proportion of acrylic resin ensures the substrate adhesion, transparency and curing performance of the protective layer, while also ensuring the structural firmness of the protective layer; the proportion of light stabilizing agent is relatively small, but it can effectively inhibit the damage of ultraviolet rays, and the light stabilizing agent enhances the protection against ultraviolet rays, preventing ultraviolet rays from causing aging or degradation of the resin, thereby effectively preventing ultraviolet light from directly irradiating the first substrate and preventing the Primer coating in the first substrate from failing.

[0024] In a specific embodiment, the light stabilizing agent includes the following components by weight: UV absorber, 0.35%-1%; antioxidant, 0.05%-0.5%; Wherein, the ultraviolet absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405; the antioxidant is one or more of RIANOX1135R and RIANOX1520.

[0025] By adopting the above technical scheme, the addition of UV absorber ensures the UV protection ability of the protective layer under sunlight, which can effectively reduce aging and yellowing caused by UV rays; the addition of antioxidant can slow down the aging of resin caused by oxidation and maintain the physical properties and appearance of the protective layer; the design of the above formula ratio enables the light stabilizing agent to effectively prevent degradation caused by UV rays and inhibit oxidation reactions, thereby enhancing the long-term stability and weather resistance of the protective layer.

[0026] In a specific implementation manner, after the semi-finished optical film is prepared in S3, the surface tension of the first substrate is tested, and the dyne value of the first substrate is measured to be 50-55 mN / m.

[0027] By adopting the above technical solution, it is shown that after the introduction of the protective layer, the first substrate still has good surface affinity and stability under ultraviolet light irradiation. Such a dyne value ensures that the first substrate can effectively adhere to the subsequent first prism layer coating, which is suitable for optical film production. It can also maintain a high level of surface tension during the production process, ensuring uniform adhesion of the film layer, excellent optical properties, reducing film defects, and improving product quality.

[0028] In a specific embodiment, the peeling force between the second prism layer and the laminating layer is 140-160 gf / in.

[0029] By adopting the above technical solution, it is shown that the second prism layer and the bonding layer have good adhesion, thereby ensuring the stability and durability of the composite film layer during use, meeting the high-requirement optical film product standards, and being able to effectively resist external forces and provide long-term reliable performance.

[0030] In summary, the beneficial technical effects of the present application are as follows: the present application designs a protective layer between the first substrate and the bonding layer, the protective layer can effectively absorb ultraviolet light, prevent excessive exposure of ultraviolet light to the Primer coating of the first substrate, reduce the risk of degradation and failure of the coating, thereby improving the adhesion between the first prism layer and the first substrate during the production process, and further improving the stability and performance of the brightness enhancement film; The composite brightness enhancement film of the present application adopts a multi-layer structure design. Both brightness enhancement films adopt a prism array structure, which increases the utilization rate of light by refracting and reflecting light, ensuring efficient light transmission and brightness enhancement of the backlight module; at the same time, the designed protective layer absorbs ultraviolet light, which not only protects the stability of the coating, but also optimizes the overall optical performance of the composite brightness enhancement film, thereby improving the high brightness and high efficiency of the backlight module. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the composite brightness enhancement film according to an embodiment of the present application.

[0032] Figure 2 It is a flow chart used to demonstrate the production of composite brightness enhancement membrane structure.

[0033] Explanation of the accompanying drawings: 1. first substrate; 2. bonding layer; 3. second prism layer; 4. second substrate; 5. first prism layer; 6. protective layer. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-2This application is described in further detail.

[0035] Embodiment 1 Reference Figure 1 The embodiment of the present application discloses a composite brightness enhancement film. In the embodiment, the composite brightness enhancement film includes but is not limited to a backlight module applied to a display device, which is used to converge the light emitted by a light source. The composite brightness enhancement film of the present application includes: The first brightness enhancement film includes a first prism layer 5 and a first substrate 1 which are stacked. In this embodiment, the first substrate 1 includes a Primer coating, which is used to increase the surface tension of the first substrate 1 so as to achieve a better adhesion effect. The first prism layer 5 is composed of a plurality of prism strips for converging light, and the plurality of prism strips are arranged in parallel in the same direction to form a prism array, forming the first prism layer 5. The second brightness enhancement film includes a second prism layer 3 and a second substrate 4 which are stacked. In this embodiment, the second substrate 4 includes a Primer coating, which is used to increase the surface tension of the second substrate 4 so as to achieve a better adhesion effect. The second prism layer 3 is composed of a plurality of prism strips for converging light, and the plurality of prism strips are arranged in parallel in the same direction to form a prism array, forming the second prism layer 3. The bonding layer 2, the first substrate 1 and the second prism layer 3 are connected by the bonding layer 2; A protective layer 6, which is disposed between the first substrate 1 and the laminating layer 2, and is used to absorb ultraviolet light; In this embodiment, the protective layer 6 is used to absorb the excess ultraviolet light when the bonding layer 2 is cured by ultraviolet light, and the absorption rate of the protective layer 6 to the excess ultraviolet light is 98% or above; thereby, the excess ultraviolet light during curing can be effectively blocked or absorbed by the protective layer 6, and at the same time, the curing effect of the bonding layer 2 during the bonding process can be guaranteed, and the transmission of excess ultraviolet light to optical elements (such as prisms, display screens, etc.) can be reduced, thereby avoiding the potential damage of excess ultraviolet light to other optical materials, and ensuring long-term stability and reliability; The thickness of the protective layer 6 is 0.5um-20um. In this embodiment, preferably, the thickness of the protective layer 6 is 2-10um. The thickness of the protective layer 6 directly affects its ultraviolet light absorption capacity. A thinner protective layer 6 cannot fully absorb ultraviolet light, while an overly thick protective layer will be saturated and cannot significantly improve the absorption effect. The optimal thickness range is 2µm-10µm. A protective layer 6 of appropriate thickness can effectively isolate ultraviolet light from invading the base material and avoid aging or degradation caused by ultraviolet light. If the thickness exceeds the optimal thickness, the ultraviolet light absorption effect of the protective layer 6 tends to be stable, and increasing the thickness will no longer improve the effect of resistance to ultraviolet light degradation. Therefore, by selecting a thickness range of 2µm-10µm, it is possible to ensure the high ultraviolet light absorption efficiency of the protective layer 6 while avoiding waste of resources or extra costs caused by excessive thickness. The present application designs a protective layer 6 between the first substrate 1 and the bonding layer 2. The protective layer 6 can effectively absorb ultraviolet light, prevent excessive exposure of ultraviolet light to the Primer coating of the first substrate 1, reduce the risk of degradation and failure of the Primer coating, thereby improving the adhesion between the first prism layer 5 and the first substrate 1 during the production process, improving the overall stability and performance of the composite brightness enhancement film, and further improving the high brightness and high efficiency of the backlight module.

[0036] The material of the protective layer 6 includes resin and light stabilizing agent; the resin is acrylic resin, which has good weather resistance and can maintain stable performance under long-term exposure to ultraviolet rays (UV) and other environmental factors (such as moisture and oxygen), reduce material aging, color fading and embrittlement caused by ultraviolet rays, and ensure the effect of the protective layer 6 absorbing ultraviolet light; and acrylic resin has high transparency. By using acrylic resin as the basic structure of the protective layer 6, the protective layer 6 can provide a clear and transparent appearance while achieving the effect of absorbing ultraviolet light, and is suitable for the incremental film of the present application to ensure its light transmittance; The light stabilizing agent includes an ultraviolet absorber and an antioxidant. In this embodiment, the light stabilizing agent can also be a combination of a hindered amine light stabilizer and an antioxidant. The present application uses an ultraviolet absorber and an antioxidant as a combination of light stabilizing agents, which can effectively delay the damage of ultraviolet rays and oxidation to the coating and the substrate, enhance the weather resistance and anti-aging ability of the material, and thus improve the overall long-term stability and optical properties. The ultraviolet absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405; the antioxidant is one or more of RIANOX1135R and RIANOX1520; in this embodiment, preferably, the ultraviolet absorber is RIASORBUV-405, and the antioxidant is RIANOX1520; By using a combination of RIASORBUV series ultraviolet absorbers and RIANOX series antioxidants, the ultraviolet absorption ability and antioxidant properties of the protective layer 6 can be greatly improved, its service life can be extended, long-term stability can be maintained, and excessive ultraviolet light exposure to the Primer coating of the first substrate 1 can be effectively avoided, further reducing the risk of degradation and failure of the Primer coating.

[0037] In this embodiment, the peeling force between the second prism layer 3 and the bonding layer 2 is 140-160 gf / in. Preferably, the peeling force between the second prism layer 3 and the bonding layer 2 in this embodiment is 150 gf / in. This peeling force range indicates that the second prism layer 3 and the bonding layer 2 have good adhesion, thereby ensuring the stability and durability of the composite film layer during use, meeting the high-demand optical film product standards, and being able to effectively resist external forces and provide long-term reliable performance.

[0038] In this embodiment, after the introduction of the protective layer 6, the dyne value of the first substrate 1 is 50-55mN / m, and the dyne value of the first substrate 1 in this embodiment is 52mN / m; it can be seen from the above parameters that after the introduction of the protective layer 6, the first substrate 1 still has good surface affinity and stability under ultraviolet light irradiation, and such a dyne value ensures that the first substrate 1 can effectively adhere to the subsequent first prism layer 5 coating, is suitable for optical film production, and can maintain a high level of surface tension during the production process, thereby ensuring uniform adhesion of the film layer, excellent optical properties, reducing film defects, and improving product quality.

[0039] In this embodiment, the adhesion of the first prism layer 5 is tested using a grid knife test method, and it is found that the coating of the first prism layer 5 has not fallen off; after the introduction of the protective layer 6, the film layers of the prepared composite brightness enhancement film have excellent adhesion, and the adhesion between the first prism layer 5 and the first substrate 1 layer is strong, and it has good durability, meeting the high-demand optical film application standards.

[0040] The brightness of the composite brightness enhancement film is 3570-3600cd / m²; this brightness range shows that the composite brightness enhancement film of the present application has a high brightness output, can meet the requirements of high-brightness display, and is suitable for various high-performance display and optical applications.

[0041] In the present application, the design of the protective layer 6 has a wide range of applicability, not only limited to POP-type composite membranes, but also applicable to MOP-type composite membranes. Specifically, the protective layer 6 can be applied to composite membrane architectures with different structural forms, especially for the composite incremental membrane provided in the present application, in which the top prism structure is triangular in shape. The protective layer 6 is also applicable to MOP-type composite membranes with a micro-transparent structure, in which the upper structure is hemispherical. In addition, due to the diverse structures of the composite membranes, the prism strips may present different heights, depths or top angles. The protective layer 6 can adapt to these different design variants, but not every variant requires a separate protective layer.

[0042] An important application scenario of the protective layer 6 is to be used in combination with a composite membrane architecture with a Primer coating. In this architecture, the Primer coating plays a role in enhancing the adhesion of the membrane surface. However, the Primer coating may be damaged due to the influence of the external environment (such as temperature, humidity, mechanical shock, etc.), which may lead to the shedding of the coating. To avoid this situation, the protective layer 6 effectively prevents the damage of the Primer resin coating through its excellent physical protection properties, thereby ensuring the integrity and long-term stability of the composite membrane.

[0043] By adopting the protective layer 6, the composite film structure with the Primer coating can maintain a longer service life in a variety of application environments, and improve the film's anti-aging, anti-scratch, anti-ultraviolet and other properties, thereby showing excellent application effects in optics, display and other fields that require high durability.

[0044] The implementation principle of Example 1 is as follows: the present application mainly designs a protective layer 6 between the first substrate 1 and the bonding layer 2. The protective layer 6 can effectively absorb ultraviolet light, avoid excessive exposure of ultraviolet light to the Primer coating of the first substrate 1, and reduce the risk of degradation and failure of the coating, thereby improving the adhesion between the first prism layer 5 and the first substrate 1 during the production process, thereby improving the stability and performance of the brightness enhancement film; the composite brightness enhancement film of the present application adopts a multi-layer structure design, and both brightening films adopt a prism array structure, which increases the utilization rate of light by refracting and reflecting light, ensuring efficient light transmission and brightness improvement of the backlight module; at the same time, by absorbing ultraviolet light through the designed protective layer 6, it can not only protect the stability of the coating, but also optimize the overall optical performance of the composite brightening film, thereby improving the high brightness and high efficiency of the backlight module.

[0045] Embodiment 2 Reference Figure 2 This embodiment provides a method for manufacturing the composite brightness enhancement film in the first embodiment, the method comprising the following steps: S1, providing a first substrate 1, forming a protective layer 6 on the first substrate 1, and then forming a bonding layer 2 on a side of the protective layer 6 away from the first substrate 1. Specifically comprising: (1) Selection and processing of the first substrate 1 First, a substrate material with good transparency and certain strength is selected as the first substrate 1, including but not limited to PET (polyethylene terephthalate) or PC (polycarbonate); in this embodiment, in order to improve the adhesion between the substrate surface and the subsequent coating, a layer of Primer coating is coated on the surface of the first substrate 1. The function of the Primer coating is to increase the tension of the substrate surface by chemical or physical means, so that the subsequent first prism layer 5 can be better adhered to the first substrate 1, thereby ensuring the stability of the first prism layer 5.

[0046] (2) Preparation of protective layer 6 A protective layer 6 is coated on the surface of the first substrate 1. The protective layer 6 is applied by coating or spraying. After coating, the protective layer 6 is cured by ultraviolet light to harden and cross-link the coating to ensure its anti-ultraviolet and anti-oxidation capabilities. The protective layer 6 plays a protective role, preventing the substrate from being damaged by ultraviolet rays, oxidation and other external environments, and ensuring the long-term stability of the optical film; the materials of the protective layer 6 are calculated by weight and include: Acrylic resin, 98.5%-99.6%; acrylic resin has good weather resistance, can maintain stable performance under long-term exposure to ultraviolet rays (UV) and other environmental factors (such as moisture, oxygen), reduce material aging, color fading and embrittlement caused by ultraviolet rays, and ensure the effect of protective layer 6 absorbing ultraviolet light; and acrylic resin has high transparency. Using acrylic resin as the basic structure of protective layer 6, protective layer 6 can achieve the effect of absorbing ultraviolet light while providing a clear and transparent appearance, which is suitable for the incremental film of the present application and ensures its light transmittance; Light stabilizing agent, 0.4%-1.5%. In this embodiment, preferably, the weight fraction of the light stabilizer is 0.5%. This component is used to improve the weather resistance of the protective layer 6 and prevent the influence of ultraviolet light on the film layer. The light stabilizing agent includes, by weight percentage: a UV absorber, 0.35%-1%; the UV absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405. In this embodiment, preferably, the UV absorber is 0.4% RIASORBUV-405. The UV absorber can effectively absorb ultraviolet rays and prevent the protective layer 6 from aging; Antioxidant, 0.05%-0.5%; the antioxidant is one or more of RIANOX1135R and RIANOX1520. In this embodiment, preferably, the antioxidant is 0.1% RIANOX1520. The antioxidant can improve the oxidation resistance of the film layer and extend the service life; A combination of RIASORBUV series UV absorbers and RIANOX series antioxidants is used. The addition of UV absorbers ensures the UV protection capability of the protective layer 6 under sunlight, and can effectively reduce aging and yellowing caused by UV rays. The addition of antioxidants can slow down the aging of the resin due to oxidation, and maintain the physical properties and appearance of the protective layer 6. The design of the above-mentioned formula ratio enables the light stabilizing agent to effectively prevent degradation caused by UV rays, and inhibit oxidation reactions, effectively avoiding excessive exposure of UV light to the Primer coating of the first substrate 1, and further reducing the risk of degradation and failure of the Primer coating.

[0047] (3) Preparation of bonding layer 2 A bonding layer 2 is applied to the side of the protective layer 6 away from the first substrate 1; the bonding layer 2 is used to bond with the second prism layer 3 of the second brightness enhancement film. The material of the bonding layer 2 includes but is not limited to UV curable resin or pressure sensitive adhesive, so that it can be quickly cured under ultraviolet light to form a strong bonding layer.

[0048] S2, providing a second substrate 4, and manufacturing a second prism layer 3 on the second substrate 4 to obtain a second incremental film; specifically comprising: (1) Selection and processing of the second substrate 4 A second substrate 4 matching the first substrate 1 is selected, including but not limited to PET (polyethylene terephthalate) or PC (polycarbonate); in this embodiment, in order to improve the adhesion between the second substrate 4 and the second prism layer 3, a Primer coating is also coated on the surface of the second substrate 4. The function of the Primer coating is to increase the surface tension of the second substrate 4, thereby improving the adhesion performance of the second prism layer 3; (2) Preparation of the Second Prism Layer 3 A second prism layer 3 is formed on the second substrate 4. The prism layer is composed of a plurality of prism bars, which are used to converge light and optimize the propagation path of light. The plurality of prism bars are arranged in parallel in the same direction to form a complete prism array. In this embodiment, the angle of the prism bars includes but is not limited to 10°-45°, and the spacing of the prism bars is designed according to the requirements of the light source to achieve the best light focusing effect; In this embodiment, the second prism layer 3 includes but is not limited to forming a prism array on the surface of the substrate by embossing technology, laser engraving or molding process; specifically including: Mold pressing: through a special mold pressing process, the prefabricated prism structure is pressed onto the surface of the second substrate 4 to form a clear prism pattern, thereby completing the production of the second prism layer 3; UV light curing molding, using ultraviolet rays to cure the coating or glue, forming the micro-prism array with the help of a die-stamping tool, and completing the production of the second prism layer 3; Laser processing uses laser etching technology to etch a prism strip structure on the surface of the substrate to form a prism array, thereby completing the production of the second prism layer 3.

[0049] S3, extrusion bonding the bonding layer 2 prepared in S1 and the second prism layer 3 prepared in S2, and irradiating them with ultraviolet light, so that the bonding layer 2 and the second prism layer 3 are cured and bonded together to obtain a semi-finished optical film; specifically comprising: (1) Lamination process The laminating layer 2 prepared by S1 and the second prism layer 3 prepared by S2 are pressed and laminated, and a certain pressure is applied to keep the two in close contact, ensuring that there are no bubbles or gaps between the laminating layer 2 and the second prism layer 3; at the same time, ultraviolet light is used for curing, ensuring that the two layers of materials are firmly bonded and that the structure of the optical film is stable; (2) Surface tension test After the bonding is completed, the surface tension of the first substrate 1 is tested, including but not limited to using an A.Shine dyne value test pen, and the surface tension of the first substrate 1 is measured to be in the range of 50-55mN / m, indicating that after the introduction of the protective layer 6, the first substrate 1 still has good surface affinity and stability under ultraviolet light. Such a dyne value ensures that the first substrate 1 can effectively adhere to the subsequent first prism layer 5 coating, is suitable for optical film production, and can maintain a high level of surface tension during the production process, ensuring uniform adhesion of the film layer, excellent optical properties, reducing film defects, and improving product quality.

[0050] S4, forming a first prism layer 5 on a side of the first substrate 1 away from the protective layer 6 to obtain a first brightness enhancement film, thereby completing the production of the composite brightness enhancement film. Specifically comprising: (1) Preparation of the first prism layer 5 A first prism layer 5 is formed on a side of the first substrate 1 away from the protective layer 6; the first prism layer 5 is composed of a plurality of prism strips, and also adopts a prism array structure design, and the angle, spacing and arrangement density of the prism strips can be optimized according to actual application requirements; the first prism layer 5 cooperates with the second prism layer 3 to enhance the reflection and guidance of light, and further improve the brightness enhancement effect; In this embodiment, the first prism layer 5 includes but is not limited to forming a prism array on the surface of the substrate by embossing technology, laser engraving or molding process; specifically including: Mold pressing: by using a special mold pressing process, the prefabricated prism structure is pressed onto the surface of the second substrate 4 to form a clear prism pattern, thereby completing the production of the first prism layer 5; UV light curing molding, using ultraviolet rays to cure the coating or glue, forming the micro-prism array with the help of a die-stamping tool, and completing the production of the first prism layer 5; Laser processing uses laser etching technology to etch a prism strip structure on the surface of the substrate to form a prism array, thereby completing the production of the first prism layer 5.

[0051] After the first prism layer 5 is manufactured, a black knife test method can be used to perform an adhesion test to ensure that there is no coating peeling on the first prism layer 5. The adhesion test can ensure that the film layer will not peel off during use.

[0052] In this embodiment, a peel force test can also be performed between the second prism layer 3 and the bonding layer 2, and the measured peel force is 140-160gf / in; the data shows that the second prism layer 3 and the bonding layer 2 have good adhesion, thereby ensuring the stability and durability of the composite film layer during use, meeting the high-demand optical film product standards, and being able to effectively resist external forces and provide long-term reliable performance.

[0053] In this embodiment, the brightness of the prepared composite brightness enhancement film can also be measured, and the measured brightness is 3570-3600cd / m², indicating that the composite brightness enhancement film of the present application has a high brightness output, meets the requirements of high-brightness display, and is suitable for various high-performance display and optical applications.

[0054] In this embodiment, an embodiment and a comparative example are designed to compare the differences in the adhesion of the first prism layer 5 and the overall performance of the composite brightness enhancement film by adding a protective layer 6 to the laminating layer 2, the second prism layer 3, and the composite brightness enhancement film; Comparative Example 1: All coatings were laminated without adding light stabilizing agents through conventional processes, and the UV dose for extrusion lamination was 1300mj / cm² (laminated layer 2). The UV dose for the extrusion lamination process in all the following comparative examples and embodiments was 1300mj / cm².

[0055] Comparative Example 2: Add 0.4% RIASORBUV-405 and 0.1% RIANOX1520 light stabilizing agents to the resin of the bonding layer 2, stir and mix, and then bond through a conventional bonding process.

[0056] Comparative Example 3: Add 0.4% RIASORBUV-405 and 0.1% RIANOX1520 light stabilizing agents to the resin of the second prism layer 3, stir and mix, and then bond through a conventional bonding process.

[0057] Example 1: Add 0.4% RIASORBUV-405 and 0.1% RIANOX1520 light stabilizing agents to the resin of the protective layer 6 and stir and mix. First, coat the protective layer 6 on the first substrate 1 to use as the upper substrate, and then use the conventional bonding process of the manufacturing method of this example to coat the bonding layer 2 and the second prism layer 3 and bond them.

[0058] The above embodiments and comparative examples are tested, and the test items of the composite brightness enhancement film provided by the present application include: 1. Surface tension test (dyne value) of the front side of the first substrate 1 at the semi-finished optical film stage after bonding in step S3: Use A.Shine dyne value test pen to test the front side of the first substrate 1; 2. Step S4: Test the adhesion of the first prism layer 5UV resin after the composite brightness enhancement film is prepared (grid test): Use a grid knife to test, use 3M-600 test tape to test, and count the number of coating peelings; 3. Composite brightness enhancement film peeling force test (measure the peeling force between the second prism layer 3 and the bonding layer 2): Use a peeling force tester to perform a peeling force test; 4. Composite brightness enhancement film brightness measurement: Use TOPCONBM-7A brightness meter to measure brightness. The test results of the comparative example and the embodiment are shown in Table 1: Table 1 According to the test results in Table 1: Comparative Example 1: No light stabilizing agent was added to any coating. After bonding, the dyne value of the front side of the first substrate 1 of the semi-finished optical film became lower, resulting in insufficient adhesion of the first prism layer 5 to the first substrate 1, and the coating fell off during testing.

[0059] Comparative Example 2: Adding a light stabilizing agent to the coating of the bonding layer 2 can protect the Primer coating of the first substrate 1 and slow down the degree of shedding of the first prism coating, but it also affects the bonding performance of the bonding layer 2 to the second prism layer 3, resulting in a decrease in the peeling force.

[0060] Comparative Example 3: Adding a light stabilizer to the coating of the second prism layer 3 can protect the Primer coating of the first substrate 1, so that the first prism layer 5 has good adhesion and the coating has not fallen off; however, the additive affects the characteristics of the material of the second prism layer 3, resulting in a decrease in product brightness and reducing product competitiveness.

[0061] Example 1: The new design provided in this application adds a protective layer 6 between the first substrate 1 and the bonding layer 2; in comparison, this protective layer 6 can effectively achieve the purpose of protecting the Primer coating of the first substrate 1 of the composite brightness enhancement film, so that the front of the first substrate 1 maintains a higher dyne value level, allowing the UV resin of the first prism layer 5 to have the best adhesion; at the same time, since the materials of the bonding layer 2 and the second prism layer 3 remain unchanged, the peeling force is maintained and the excellent brightness performance of the product is guaranteed, with an excellent comprehensive effect.

[0062] The manufacturing method of the composite brightness enhancement film of the present application can effectively enhance the brightening effect of the optical film, improve the durability and mechanical strength of the film by introducing a protective layer 6 to optimize the film structure design, combining ultraviolet light curing technology and precise bonding technology. The adhesion, peeling force and brightness stability of the entire composite brightness enhancement film are optimized. The protective layer 6 not only effectively ensures the high value of the Primer coating of the first substrate 1, promotes the adhesion of the UV resin of the first prism layer 5, but also maintains the stability of the peeling force and the excellent performance of the brightness. This makes the composite film have excellent comprehensive performance, not only has strong mechanical properties, but also can meet the requirements of high-brightness display, and is suitable for various high-performance display and optical applications.

[0063] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A composite brightness enhancement film, characterized in that: include: The first brightness enhancement film comprises a first prism layer and a first substrate which are stacked; The second brightness enhancement film comprises a second prism layer and a second substrate which are stacked; A bonding layer, wherein the first substrate and the second prism layer are connected by the bonding layer; A protective layer is disposed between the first substrate and the laminating layer, and is used for absorbing ultraviolet light.

2. The composite brightness enhancement film according to claim 1, characterized in that: The protective layer is used to absorb excess ultraviolet light when the bonding layer is cured with ultraviolet light, and the absorption rate of the protective layer to the excess ultraviolet light is 98% or above.

3. The composite brightness enhancement film according to claim 1, characterized in that: The materials of the protective layer include resin and light stabilizing agent.

4. The composite brightness enhancement film according to claim 3, characterized in that: The light stabilizing agent comprises an ultraviolet absorber and an antioxidant.

5. The composite brightness enhancement film according to claim 4, characterized in that: The ultraviolet absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405; the antioxidant is one or more of RIANOX1135R and RIANOX1520.

6. The composite brightness enhancement film according to claim 3, characterized in that: The resin is acrylic resin.

7. The method according to claim 1, characterized in that: The thickness of the protective layer is 0.5um-20um.

8. A method for producing the composite brightness enhancement film according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. providing a first substrate, forming a protective layer on the first substrate, and then forming a bonding layer on a side of the protective layer away from the first substrate; S2, providing a second substrate, and manufacturing a second prism layer on the second substrate to obtain a second incremental film; S3, extrusion-bonding the bonding layer obtained in S1 and the second prism layer obtained in S2, and irradiating them with ultraviolet light, so that the bonding layer and the second prism layer are cured and bonded together, to obtain a semi-finished optical film; S4. Making a first prism layer on a side of the first substrate away from the protective layer to obtain a first brightness enhancement film, thereby completing the production of the composite brightness enhancement film.

9. The method according to claim 8, characterized in that: The materials of the protective layer include the following components by weight: acrylic resin, 98.5%-99.6%; light stabilizing agent, 0.4%-1.5%.

10. The method according to claim 9, characterized in that: The light stabilizing agent comprises the following components by weight: ultraviolet absorber, 0.35%-1%; Antioxidants, 0.05%-0.5%; Wherein, the ultraviolet absorber is one or more of RIASORBUV384-2, RIASORBUV-400, and RIASORBUV-405; the antioxidant is one or more of RIANOX1135R and RIANOX1520.

11. The method according to claim 8, characterized in that: After the semi-finished optical film is obtained in S3, the surface tension of the first substrate is tested, and the dyne value of the first substrate is measured to be 50-55 mN / m.

12. The method according to claim 8, characterized in that: The peeling force between the second prism layer and the laminating layer is 140-160 gf / in.

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