Novel optical composite film

Abstract

The invention discloses a novel optical composite film, and relates to the technical field of electronic display devices, the novel optical composite film comprises an intermediate base material JKS-CP-1, an adhesive JKS-A is arranged on the upper layer of the intermediate base material JKS-CP-1, an adhesive JKS-B is arranged on the lower layer of the intermediate base material JKS-CP-1, the adhesive JKS-A and the adhesive JKS-B are one or more mixtures of acrylic acid or polyurethane adhesives, and the refractive index is 1.4-1.6. According to the novel optical composite film, JKS-CP-1, an adhesive JKS-A and an adhesive JKS-B are arranged, micro-processing such as birefringence particle coating and corona is carried out on the surface of a main optical film, so that the novel optical composite film can achieve higher circular polarization conversion efficiency and better brightness uniformity, blanking is carried out through mechanical matching alignment or optical fiber alignment of a coating machine, and the production efficiency of the novel optical composite film is improved. The novel optical composite film is simpler in manufacturing process and higher in yield.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic display devices, and specifically relates to a novel optical composite film. Background Art

[0002] Studies have shown that people experience less visual fatigue when viewing a circularly polarized screen compared to a linearly polarized screen. In terms of the polarization direction, linearly polarized light refers to light whose electric vector vibrates in a fixed direction within a plane perpendicular to the propagation direction. The electric field vector of circularly polarized light rotates in a circle in the propagation direction and is closer to natural light than linearly polarized light, which may stimulate the eyes more evenly and thus reduce visual fatigue. In recent years, with the improvement of people's awareness of eye protection, the research on optical films with circular polarization characteristics has gradually increased.

[0003] Currently, the technology for circularly polarized light display on the market adopts the QWP scheme, that is, a quarter-wave plate layer is prepared from liquid crystal or a crystal material with birefringence properties to change the path of light and convert linearly polarized light into circularly polarized light. However, due to the physical property limitations of the material for preparing the wave plate layer in this scheme, the problem of low circularly polarized light conversion rate of the display screen occurs.

[0004] The present invention proposes a novel optical composite film. An optical composite film with a higher circular polarization conversion efficiency can be prepared by a method with a simpler process and a higher yield. The novel optical composite film uses processes such as unidirectional stretching to prepare a PET film with different axial refractive indices. First, the surface of the film is corona-treated to improve the surface bonding force, and then a coating layer with birefringent particles is bonded to the surface of the PET film. By increasing the phase retardation amount, a higher circular polarization conversion efficiency is obtained. Finally, a vacuum pump is installed instead of the previous extrusion type during the coating of the adhesive to reduce the yield loss caused by the phenomenon of glue overflow. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a novel optical composite film, and a higher circular polarization conversion efficiency is obtained by a method with a simpler process and a higher yield, so as to solve the technical problems proposed in the above background.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A novel optical composite film is composed of three layers, including an intermediate substrate JKS-CP-1, and two different types of adhesives JKS-A and JKS-B on the upper and lower layers of the substrate.

[0007] As a preferred technical solution, JKS-CP-1 is a PET film with birefringence prepared by processes such as unidirectional stretching of a polymer material. Then, the surface is corona-treated, and the adhesive is directly coated on the surface-treated film or a coating layer with birefringent particles is added and then the adhesive is coated.

[0008] As a preferred technical solution, the PET film is a polymer organic film with birefringence prepared by processes such as polymerization, film formation, stretching, and surface processing of polymer materials. The stretching method used is unidirectional stretching, and the stretching ratio is ≥3 times. The visible light transmittance of the PET film product is ≥85% (thickness <100μm), the haze is <1.5%, and the birefringence Δn is 0.1–0.15.

[0009] As a preferred technical solution, both sides of the PET film are subjected to corona treatment with a power of 30 - 50 W·min / m 2 , with an electrode spacing of 1 - 2 mm, to oxidize its surface. After the surface corona treatment, the surface tension of the PET is 48–56 mN / m.

[0010] As a preferred technical solution, the coating doped with birefringent particles uses silicone-based coatings, polyurethane-based coatings, acrylate-based coatings, or their modified derivatives as the main coating resin. The doped birefringent particles include one or more of quartz powder, calcium carbonate, magnesium hydroxide, mica, and magnesium hydroxide. The particle size of the doped birefringent particle powder is 1 - 14μm, and mechanical stirring dispersion is used. The mass fraction of the birefringent particle powder accounts for 2 - 50% of the total mixture.

[0011] As a preferred technical solution, the adhesives JKS-A and JKS-B coated on both sides of the substrate JKS-CP-1 are one or more mixed adhesives of acrylic or polyurethane types, and JKS-A and JKS-B have a certain refractive index, with the refractive index being 1.4 - 1.6.

[0012] As a preferred technical solution, feeding is carried out through mechanical cooperation alignment or fiber alignment of a coater. In a vacuum environment, JKS-A and JKS-B are bonded to the substrate JKS-CP-1, and the UV curing energy is 1500–2000 mJ / cm 2 , and the curing time is 5–30 s.

[0013] In summary, the present invention mainly has the following beneficial effects:

[0014] By setting JKS-CP-1, adhesive JKS-A, and adhesive JKS-B, and preparing through processes such as polymerization, film formation, stretching, and surface processing, the novel optical composite film can achieve higher circular polarization conversion efficiency and better brightness uniformity. And by feeding through mechanical cooperation alignment or fiber alignment of a coater, the manufacturing process of the novel optical composite film is simpler and the yield is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the circular polarization conversion efficiency and brightness uniformity of each embodiment of the present invention under white, red, green, and blue pictures;

[0016] Figure 2 The following are the trends of (a) refractive index (nx, ny, nz) and (b) anisotropy and planar orientation of PET films under the uniaxial stretching process of the present invention.

[0017] Figure 3 Two structural diagrams of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0019] The following describes an embodiment of the present invention based on its overall structure.

[0020] Comparative Example 1

[0021] QWP type circular polarizing film

[0022] Example 1

[0023] 1. JKS-CP-1 substrate film is prepared by polymerization, film forming, stretching and other processes. The stretching method adopts unidirectional stretching process, the stretching temperature is 120℃, the stretching ratio is 5 times, and then the power is 50W·min / m on both sides. 2 , corona treatment with an electrode spacing of 1mm, followed by winding and slitting.

[0024] 2. Calcium carbonate powder with a particle size of 1-5 μm was added to the main acrylic coating resin at a ratio of 1% by mass of the birefringent particle powder to the total mixture. After mechanical dispersion, it was coated on both sides of the corona-treated PET. After the coating was cured, the substrate JKS-CP-1 was obtained.

[0025] 3. Through the mechanical alignment of the coating machine or the alignment of the optical fiber, the adhesive is coated with the 70μm substrate JKS-CP-1 under vacuum environment, and the UV curing energy is 2000mJ / cm 2 The curing time is 5s, and JKS-A with a thickness of 75μm and adhesive JKS-B with a thickness of 75μm are coated on the upper and lower layers of the substrate JKS-CP-1 respectively.

[0026] Example 2

[0027] 1. JKS-CP-1 substrate film is prepared by polymerization, film forming, stretching and other processes. The stretching method adopts unidirectional stretching process, in which the stretching temperature is 100℃, the stretching ratio is 3 times, and then the power is 30W·min / m on both sides. 2, The electrode spacing is 1 mm for corona treatment, followed by winding and slitting.

[0028] 2. Calcium carbonate with a powder particle size of 1 - 5 μm is added to the main resin of the mixed coating of acrylic and urethane at a proportion of 2% by mass fraction of the birefringent particle powder in the total mixture. After mechanical dispersion and uniformity, it is coated on both sides of the corona-treated PET. After the coating is cured, the substrate JKS-CP-1 is obtained.

[0029] 3. Feeding is carried out through mechanical alignment or fiber alignment of the coater. In a vacuum environment, the adhesive is coated and bonded with the 80-μm substrate JKS-CP-1. The UV curing energy is 1500 mJ / cm 2 , The curing time is 5 s. JKS-A with a thickness of 50 μm and the adhesive JKS-B with a thickness of 100 μm are respectively coated on the upper and lower layers of the substrate JKS-CP-1.

[0030] Example 3

[0031] 1. The JKS-CP-1 substrate film is prepared through processes such as polymerization, film formation, and unidirectional stretching. The stretching temperature is 100 °C, and the stretching ratio is 3 times. Then, both sides are subjected to corona treatment with a power of 50 W·min / m 2 , The electrode spacing is 1 mm for corona treatment, followed by winding and slitting.

[0032] 2. Calcium carbonate with a powder particle size of 1 - 5 μm is added to the main resin of the mixed coating of acrylic and urethane at a proportion of 5% by mass fraction of the birefringent particle powder in the total mixture. After mechanical dispersion and uniformity, it is coated on both sides of the corona-treated PET. After the coating is cured, the substrate JKS-CP-1 is obtained.

[0033] 3. Feeding is carried out through mechanical alignment or fiber alignment of the coater. In a vacuum environment, the adhesive is coated and bonded with the 80-μm substrate JKS-CP-1. The UV curing energy is 1500 mJ / cm 2 , The curing time is 5 s. JKS-A with a thickness of 100 μm and the adhesive JKS-B with a thickness of 50 μm are respectively coated on the upper and lower layers of the substrate JKS-CP-1.

[0034] Example 4

[0035] 1. The JKS-CP-1 substrate film is prepared through processes such as polymerization, film formation, and stretching. The stretching method used is the unidirectional stretching process. The stretching temperature is 100 °C, and the stretching ratio is 3 times. Then, both sides are subjected to corona treatment with a power of 50 W·min / m 2 , The electrode spacing is 2 mm for corona treatment, followed by winding and slitting.

[0036] 2. Add quartz powder with a powder particle size of 1 - 5 μm into the main resin of the mixed coating of acrylic and urethane types at a proportion of 10% by mass of the birefringent particle powder in the total mixture. After mechanical dispersion and uniformity, coat both sides of the corona-treated PET. After the coating is cured, the substrate JKS-CP-1 is obtained.

[0037] 3. Feed materials through mechanical alignment or fiber alignment by a coater. Under a vacuum environment, bond the adhesive to the 90 μm substrate JKS-CP-1 by coating. The UV curing energy is 1500 mJ / cm 2 , the curing time is 5 s. Coat JKS-A with a thickness of 100 μm and the adhesive JKS-B with a thickness of 50 μm on the upper and lower layers of the substrate JKS-CP-1 respectively.

[0038] It can be seen from Figures 1 to 3 that Comparative Example 1 is a circularly polarized film of the QWP type. Since the phase retardation of the circularly polarized film of the QWP type is small, its circular polarization conversion efficiency is lower and the brightness uniformity is also worse. The circularly polarized optical composite film with a uniaxially stretched film as the substrate increases the phase retardation, so its circular polarization conversion efficiency is greater. Based on the PET substrate, the solution in the present invention coats a particle powder coating with birefringent properties on both sides thereof, further increasing the phase retardation of the product, making the circular polarization conversion efficiency of the product further improved and the brightness uniformity better.

[0039] Although the embodiments of the present invention have been shown and described, the specific embodiments are only explanations of the present invention and are not limitations thereof. The specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art can make modifications, substitutions and variations without creative contributions to the embodiments according to needs, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A novel optical composite film, characterized in that, It includes an intermediate substrate JKS-CP-1, with an adhesive JKS-A provided on the upper layer of the intermediate substrate JKS-CP-1, and an adhesive JKS-B provided on the lower layer of the intermediate substrate JKS-CP-1. The adhesives JKS-A and JKS-B are one or more mixtures of acrylic or polyurethane adhesives, and the refractive index is 1.4 - 1.

6.

2. The novel optical composite film according to claim 1, wherein: The partial preparation process of the intermediate substrate JKS-CP-1 is as follows: Step 1: Stretching. The polymer material is subjected to a stretching process (the stretching direction is unidirectional stretching, and the stretching ratio is ≥3 times its own. The visible light transmittance of the PET film is ≥85% (thickness < 100μm), the haze is < 1.5%, and the birefringence Δn is 0.1–0.15)) to prepare a PET film with birefringence. Step 2: Corona treatment. The surface of the PET film with birefringence is subjected to corona treatment, and the surface tension of the PET after surface corona treatment is 48–56 mN / m. Step 3: Coating. Birefringent particle coatings are added to both the upper and lower surfaces of the surface-treated PET film, and then adhesives are coated on both the upper and lower surfaces of the PET film.

3. A novel optical composite film according to claim 1, characterized in that: The adhesives JKS-A and JKS-B are one or two mixed adhesives of acrylic or polyurethane.

4. The novel optical composite film according to claim 2, characterized in that: The birefringent particle coating is one or more mixed coatings of silicone-based coatings, polyurethane-based coatings, and acrylate-based coatings.

5. A novel optical composite film according to claim 1, characterized in that: The birefringent particle coating includes: quartz powder, calcium carbonate, magnesium hydroxide, mica, magnesium hydroxide. The particle size of the birefringent particle powder is 1 - 14μm, and the mass fraction of the birefringent particle powder in the total mixture is 2 - 50%.

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