CN114114501A

CN114114501A - Polarization-maintaining optical film and polarization-maintaining prism film

Info

Publication number: CN114114501A
Application number: CN202110989795.3A
Authority: CN
Inventors: 夏寅; 冯金刚; 高斌基; 付坤; 刘建凯; 赵国林; 唐海江; 李刚; 张彦
Original assignee: Ningbo Exciton Technology Co Ltd
Current assignee: Ningbo Exciton Technology Co Ltd
Priority date: 2020-08-31
Filing date: 2021-08-26
Publication date: 2022-03-01

Abstract

The invention relates to a de-interference polarization-maintaining prism film, in particular to a polarization-maintaining prism film applied to an LCD linear polarization backlight source and a preparation method thereof. The invention provides a polarization-maintaining prism film for interference elimination and a preparation method thereof, aiming at solving the problem that an optical film in the traditional backlight can generate depolarization in a polarization light source synergy scheme. The interference-relieving polarization-maintaining prism film comprises a polarization-maintaining base layer, a first structural layer and a second structural layer, wherein the first structural layer is a prism layer and is positioned on the upper surface of the base layer, and the second structural layer is not present or is an atomizing layer and is positioned on the lower surface of the base layer. The prism layer is formed by tiling a plurality of same or different prism ribs. The triangular prism ribs are shaken right and left in the longitudinal direction. When linearly polarized light in the LCD backlight passes through the interference-elimination polarization-maintaining prism film, higher incident light polarization degree can be reserved, the polarization-maintaining degree is not lower than 96%, the final high transmission of the LCD lower polarizer is ensured, and the utilization rate of the backlight source is further improved.

Description

Polarization-maintaining optical film and polarization-maintaining prism film

Technical Field

The invention relates to a polarization-maintaining optical film, in particular to a polarization-maintaining optical film applied to an LCD linear polarization backlight source and a polarization-maintaining prism film.

Background

In the conventional Liquid Crystal Display (LCD) field, the display of the LCD panel requires a backlight module to provide a light source for the LCD panel, and the LED point light source can be converted into a uniform planar light source through various optical films and light guide plates in the backlight module. However, the light energy of the planar light source is actually very inefficient for the liquid crystal panel.

One reason for this is that the transmittance of the lower polarizer (13) of the liquid crystal panel is only 40% (as shown in table 1). Since the conversion efficiency from point light source to surface light source is greatly different due to different backlight designs (direct or side-in type), the light energy attenuation process of the traditional liquid crystal display panel to the backlight source is discussed by taking the surface light source as a 100% standard. It can be seen that the loss is the most (about 70%) when passing through the optical filter, because the white light is filtered to remove the other two colors to generate RGB monochromatic light, and secondly, the loss is relatively serious (about 60%) when passing through the lower polarizer initially, because the ordinary light source forms linear polarization, and needs to go through the dichroic absorption process of the PVA layer, only the linear polarization (22) with the polarization direction parallel to the transmission axis of the polarizer is retained, and the linear polarization (22) in the vertical direction is absorbed, as shown in fig. 1, the light emitted from the backlight module (14) is partial polarization (21), the linear polarization (22) in the parallel direction is smoothly transmitted after the partial polarization (21) passes through the lower polarizer (13), the linear polarization (23) in the vertical direction is absorbed by the lower polarizer (13), and the linear polarization in the parallel direction is twisted by the liquid crystal and changes the polarization direction when passing through the liquid crystal panel (12), and is transformed into the linear polarization (23) in the vertical direction and smoothly transmitted through the upper polarizer (11), the emitted light is finally linearly polarized light (23) in the vertical direction.

Table 1 light energy attenuation process of conventional lcd panel to backlight

Investigation sequence	Attenuation position	Cause of attenuation	Transmittance of light	Residual light energy
					6	Cover plate	Surface reflection	90％	9.2％
5	Upper polarizer	Surface reflection	90％	10.3％
					4	Optical filter	Wavelength cut-off and absorption	30％	11.4％
3	Liquid crystal layer	Transmission of polarized light	95％	38％
					2	Lower polarizer	Surface reflection and polarization	40％	40％
1	Area light source	Backlight material light distribution conversion	/	100％
					0	Point light source	/	/	/

If the polarized light of the backlight surface light source is polarized before entering the polarized light, the polarized light is converted into linearly polarized light parallel to the backlight surface light source, so that the transmittance of the polarized light to the backlight surface light source is greatly improved, the utilization rate of the whole liquid crystal panel to the surface light source is greatly improved, the brightness of the display is improved, and the electricity and the energy are saved.

The traditional synergy scheme is back-end polarization, that is, a reflection type polarizer (RP) (15) adopting a multilayer film system design is added to the original backlight framework: the reflection type polarizer (15) can transmit the completely polarized P light and reflect the S light; the S light can emit depolarized light in the backlight system to reform partial polarized light; part of the polarized light is repeatedly transmitted from the RP to generate more P light; circulating for many times until the energy is exhausted; the increased P light can increase the light energy utilization rate by 20-30% compared with the original structure. As shown in fig. 2, the light emitted from the backlight module (14) is partially polarized light (21), the partially polarized light (21) enters the reflective polarizer (15), and the reflective polarizer (15) can transmit linearly polarized light (22) in the parallel direction and reflect linearly polarized light (23) in the perpendicular direction; linearly polarized light (23) in the vertical direction can be depolarized in the backlight system to form partially polarized light (21) again; after the linearly polarized light (22) in the parallel direction passes through the lower polarizer (13), the linearly polarized light (22) in the parallel direction smoothly transmits, no linearly polarized light (23) in the vertical direction is absorbed at the moment, the linearly polarized light in the parallel direction is twisted by liquid crystal when passing through the liquid crystal panel (12), the polarization direction is changed, the linearly polarized light (23) in the vertical direction is converted into the linearly polarized light (23) in the vertical direction and smoothly transmits from the upper polarizer (11), and emergent light is finally the linearly polarized light (23) in the vertical direction.

However, the reflective polarizer is very expensive due to its complicated equipment and process, and low supply resources. Therefore, there is a need to propose new synergistic solutions.

Another feasible scheme is front-end polarization, namely a backlight module adopts a linear polarization point light source to emit linearly polarized light from the beginning, and the direction of the polarized light is consistent with the transmission axis of the lower polarizer (13). As shown in fig. 3, the light emitted by the backlight module (14) is linearly polarized light (22) in the parallel direction, after the linearly polarized light (22) passes through the lower polarizer (13), the linearly polarized light (22) in the parallel direction smoothly transmits, when the linearly polarized light passes through the liquid crystal panel (12), the linearly polarized light is twisted by the liquid crystal and changes the polarization direction, the linearly polarized light is converted into linearly polarized light (23) in the vertical direction and smoothly transmits from the upper polarizer (11), and the emergent light is finally linearly polarized light (23) in the vertical direction. However, in the process of converting the linear polarization point light source into the surface light source, because the conventional optical film has optical anisotropy and a very low polarization maintaining degree (completely polarized light is incident and is subjected to more or less depolarization through the optical film, the polarization degree of the emergent light is reduced, partial polarized light is generated, the polarization maintaining degree, which is the ratio of the polarization degree of the emergent light to the polarization degree of the incident light, is also expressed by the polarization degree of the emergent light because the polarization degree of the incident light is 1, generally between 50% and 70%, and finally the polarization degree of the surface light source is rapidly reduced, and a significant depolarization phenomenon is generated, while the partial polarized light is still filtered by the lower polarizer to a large extent, and the expected synergy is not achieved, as shown in fig. 4, after linearly polarized light (22) in the parallel direction passes through the conventional optical film (3), the emergent light is partially polarized light (21), and after the partially polarized light (21) passes through the lower polarizer (13), linearly polarized light (22) in the parallel direction smoothly transmits, linearly polarized light (23) in the vertical direction is absorbed by the lower polarizer (13), the linearly polarized light in the parallel direction is twisted by liquid crystal when passing through the liquid crystal panel (12), the polarization direction is changed, the linearly polarized light (23) in the vertical direction is converted into the linearly polarized light (23) in the vertical direction and smoothly transmits from the upper polarizer (11), and emergent light is finally the linearly polarized light (23) in the vertical direction.

Disclosure of Invention

The invention provides a polarization-maintaining optical film and a preparation method thereof, aiming at solving the problem that the optical film in the traditional backlight can generate a serious depolarization phenomenon in a polarization light source synergy scheme. The polarization-maintaining optical film provided by the invention has higher polarization maintaining degree for incident linearly polarized light, and the polarization-removing phenomenon is reduced.

In order to solve the technical problems, the invention adopts the following technical scheme:

the invention provides a polarization-maintaining optical film which comprises a polarization-maintaining base layer, a first structural layer and/or a second structural layer, wherein the first structural layer is positioned on the upper surface of the polarization-maintaining base layer, and the second structural layer is positioned on the lower surface of the polarization-maintaining base layer.

When linearly polarized light passes through the polarization-maintaining optical film, the polarization-maintaining optical film has a polarization maintaining degree of greater than or equal to 80% for incident linearly polarized light.

Further, when linearly polarized light in the LCD backlight passes through the polarization maintaining optical film, the polarized incident light may retain a higher polarization degree, and the polarization maintaining degree is greater than or equal to 80%. Thereby ensuring the final high transmission of the polarizer under the LCD and greatly improving the utilization rate of the backlight source.

The optical film in the conventional backlight refers to an existing diffusion film, microlens film, prism film, or inverse prism film.

The polarization-maintaining optical film is one of a polarization-maintaining diffusion film, a polarization-maintaining micro-lens film, a polarization-maintaining prism film and a polarization-maintaining inverse prism film.

The polarization-maintaining optical film provided by the invention is an improvement of the existing optical film, and the material of a base layer (also called a supporting layer) of the existing optical film is changed into a material with high polarization-maintaining degree to linearly polarized light.

The polarization maintaining matrix layer has a polarization maintaining degree of more than 99%.

The polarization-maintaining matrix layer is made of optically isotropic transparent polymer.

The thickness T of the polarization-maintaining matrix layer is 25-250 mu m.

The material of the polarization-maintaining matrix layer is selected from one or the combination of at least two of polymethyl methacrylate (PMMA), Polycarbonate (PC), Triacetylcellulose (TAC) and Cyclic Olefin Polymer (COP).

The haze of the polarization-maintaining diffusion film is 60-98%.

The first structural layer of the polarization-maintaining diffusion film is an atomized layer, the second structural layer does not exist or is the atomized layer, and the atomized layer is selected from a non-particle coating or a particle coating.

The haze of the first atomized layer/the second atomized layer is 5-98%.

The particle-free coating of the polarization-maintaining diffusion film is composed of a transparent polymer resin. The particle-coated layer is composed of a transparent polymer resin and transparent polymer particles; the particle diameter of the transparent polymer particles is 1 to 20 μm.

The haze of the polarization-maintaining micro-lens film is 60-98%.

The first structural layer of the polarization-maintaining micro-lens film is a micro-lens array layer; in the microlens array layer, the coordinates of the main optical axes of three adjacent microlenses are connected to form a regular triangle, or the coordinates of the main optical axes of four adjacent microlenses are connected to form a square; the microlenses in the microlens array are closely arranged.

The haze of the micro-lens array layer is 60-98%.

In the microlens array layer, the distance D between the main optical axes of adjacent microlenses is 10-50 μm, the width of each microlens is W (W ═ D), the height of each microlens is H, and the aspect ratio H/W is 0.05-0.5.

The first structural layer of the polarization-maintaining prism film is a prism layer, and the second structural layer is absent or is an atomized layer; the prism layer is formed by tiling prism ribs, the cross sections of the prism ribs are isosceles triangles, the bottom edges of the triangles are 10-100 mu m, and the vertex angles are 75-105 degrees; the haze of the atomization layer is 0-30%.

The second structural layer of the polarization-maintaining inverse prism film is an inverse prism layer, and the first structural layer does not exist or is an atomized layer; the inverted prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles or common triangles, the width L of the bottom side of each triangle is 10-100 mu m, the vertex angle theta is selected from 40-80 degrees, preferably 60 degrees, one larger bottom angle alpha is 90-0.5 theta + gamma, gamma is 0-10 degrees, when gamma is 0 degree, the cross section is isosceles triangle, and when gamma is more than 0 degree, the cross section is common triangle. The haze of the atomization layer is 0-60%.

The material of the atomizing layer is selected from one of AR (Acrylic resin or modified Acrylic resin), PMMA, PC or Polyurethane (PU). AR is preferably a photo-curing process, PMMA, PC are preferably a hot-pressing process, and PU is preferably a thermal-curing process.

When the atomized layer is a particle coating, the refractive index na of the transparent polymer resin is selected from 1.4-1.65. When the atomized layer is a particle-free coating, the refractive index nb of the transparent polymer resin is selected from 1.4-1.65.

The transparent polymer particles are selected from one or a combination of at least two of PMMA, PBMA (polybutylmethacrylate), PS (polystyrene), PU (polyurethane) and organosilicon.

The microlens array layer is formed by transparent polymer resin, and the material of the transparent polymer resin is selected from one of AR, PMMA or PC. AR is preferably a photo-curing process, and PMMA, PC are preferably a hot-pressing process. The refractive index nc of the transparent polymer resin of the micro-lens array layer is selected from 1.4-1.65.

The prism layer is made of transparent polymer resin, and the material of the transparent polymer resin is selected from one of AR, PMMA and PC. AR is preferably a photo-curing process, and PMMA, PC are preferably a hot-pressing process. The refractive index nd of the transparent polymer resin is selected from 1.5-1.65.

The reverse prism layer is made of transparent polymer resin, and the material of the transparent polymer resin is selected from one of AR, PMMA and PC. AR is preferably a photo-curing process, and PMMA, PC are preferably a hot-pressing process. The refractive index ne of the transparent polymer resin of the prism layer is selected from 1.5-1.65.

Further, in the polarization-maintaining diffusion film provided by the invention, the first structural layer is an atomized layer dl (diffusion layer), and the second structural layer is not present. The thickness T of the substrate layer is 50-250 μm, the polarization-maintaining substrate layer is made of PC, TAC, PMMA or COP, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining diffusion film is 98%. The haze of the first atomization layer is 98%, the type of the atomization layer is a particle coating, the transparent polymer resin is selected from PU or AR, the transparent polymer particles are PMMA, PS, organic silicon or PU, the particle size d is 5-15 mu m or 8-20 mu m, and the refractive index na of the transparent polymer resin is 1.4, 1.5 or 1.65. The polarization-maintaining diffusion film has a polarization maintaining degree of 81-83% (e.g., 81%, 82%, or 83%).

The first structural layer is an atomized layer DL (diffusion layer), and the second structural layer does not exist. The thickness T of the substrate layer is 250 mu m, the polarization-maintaining substrate layer is made of PC, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining diffusion film is 98%. The haze of the first matte layer is 98%, the type of the matte layer is a particle-free coating, the transparent polymer resin is PC, and the refractive index na of the transparent polymer resin is 1.5. The polarization maintaining diffusion film has a polarization maintaining degree of 83%.

According to the polarization-maintaining diffusion film provided by the invention, the first structural layer is an atomized layer, and the second structural layer is an atomized layer. The thickness T of the matrix layer is 50-250 μm (for example, 25 μm, 50 μm, 100 μm, 125 μm, 250 μm), the polarization-maintaining matrix layer is made of PC or PMMA, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining diffusion film is 60-98% (for example, 60%, 80%, 90%, 95% or 98%). The haze of the first atomization layer is 98%, the type of the atomization layer is a particle coating, the transparent polymer resin is PU or AR, the transparent polymer particles are PMMA, the particle size d is 5-15 mu m, and the refractive index na of the transparent polymer resin is 1.5 or 1.65. The haze of the second atomization layer is 5%, the type of the second atomization layer is a particle coating, the transparent polymer resin is AR, the transparent polymer particles are PMMA, the particle size d is 1-3 micrometers or 5-15 micrometers, and the refractive index na of the transparent polymer resin is 1.5.

According to the polarization-maintaining diffusion film provided by the invention, the first structural layer is an atomized layer, and the second structural layer is an atomized layer. The thickness T of the substrate layer is 250 mu m, the polarization-maintaining substrate layer is made of PC, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining diffusion film is 98%. The haze of the first atomization layer is 98%, the type of the atomization layer is a particle coating, the transparent polymer resin is PU or AR, the transparent polymer particles are PMMA, the particle size d is 5-15 mu m, and the refractive index na of the transparent polymer resin is 1.5 or 1.65. The haze of the second matte layer is 5%, the matte layer is a particle-free coating and is composed of a transparent polymer resin AR, and the refractive index nb of the transparent polymer resin is 1.5 or 1.6. The polarization maintaining diffusion film has a polarization maintaining degree of 80%.

Further, the invention provides a polarization-maintaining microlens film, wherein the first structural layer is a microlens array layer ml (microlens layer), and the second structural layer is not present. The thickness T of the matrix layer is 25-250 μm (for example, 25 μm, 50 μm, 100 μm, 125 μm, 250 μm), the material of the polarization-maintaining matrix layer is selected from PC or PMMA, the optical isotropy is realized, the polarization maintaining degree is > 99%, and the haze of the polarization-maintaining micro-lens film is 60-98% (for example, 60%, 70%, 85%, 92%, 96%, 98%). The microlens array layer has a haze of 98%, and is formed of a transparent polymer resin AR or PC having a refractive index nc of 1.4-1.65 (e.g., 1.4, 1.5, 1.65). In the microlens array layer, the distance D between the main optical axes of adjacent microlenses is 10 μm to 50 μm (for example, 10 μm, 20 μm, 35 μm, 50 μm), the width of a microlens is W (W ═ D), the height of a microlens is H, and the aspect ratio H/W is 0.05 to 0.5 (for example, 0.05, 0.1, 0.2, 0.5); the polarization maintaining micro lens has a polarization maintaining degree of 80% -97% (e.g. 80%, 85%, 88%, 90%, 95%, 97%).

The invention provides a polarization-maintaining micro-lens film, wherein a first structural layer is a micro-lens array layer, and a second structural layer is an atomizing layer. The thickness T of the substrate layer is 250 mu m, the polarization-maintaining substrate layer is made of PC (polycarbonate), the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining micro-lens film is 96%. The haze of the microlens array layer is 98%, the microlens array layer is composed of a transparent polymer resin AR, and the refractive index nc of the transparent polymer resin is 1.5. In the microlens array layer, the pitch D of the main optical axes of adjacent microlenses is 50 μm, the width of a microlens is W (W ═ D), the height of a microlens is H, and the aspect ratio H/W is 0.5. The haze of the atomization layer is 5%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining micro-lens film has 85% polarization maintaining degree.

The invention provides a polarization-maintaining micro-lens film, wherein a first structural layer is a micro-lens array layer, and a second structural layer is an atomizing layer. The thickness T of the substrate layer is 100 mu m, the polarization-maintaining substrate layer is made of TAC, PMMA or COP, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining micro-lens film is 96%. The haze of the microlens array layer is 98%, the microlens array layer is formed of a transparent polymer resin AR or PMMA, and the refractive index nc of the transparent polymer resin is 1.5. In the microlens array layer, the pitch D of the main optical axes of adjacent microlenses is 50 μm, the width of a microlens is W (W ═ D), the height of a microlens is H, and the aspect ratio H/W is 0.5. The haze of the atomization layer is 5%, the type of the atomization layer is a particle coating and is composed of transparent polymer resin AR and transparent polymer resin particles PMMA, the refractive index nb of the transparent polymer resin is 1.5, and the particle size of the polymer resin particles PMMA is 3-5 microns. The polarization maintaining micro-lens film has 85% polarization maintaining degree.

Further, the present invention provides a polarization maintaining prism film, wherein the first structural layer is a prism layer pl (prism layer), and the second structural layer is absent. The thickness T of the matrix layer is 25-250 μm (for example, 25 μm, 50 μm, 100 μm, 125 μm, 250 μm), the polarization-maintaining matrix layer is made of PC, TAC, PMMA or COP, the prism layer is made of transparent polymer resin AR, PMMA or PC, and the refractive index nd of the transparent polymer resin is 1.5-1.65 (for example, 1.5, 1.55 or 1.65). The prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the bottom edges of the triangles are 10-100 mu m (such as 10-20 mu m, 50 mu m and 100 mu m), and the vertex angles are 75-105 degrees (such as 75 degrees, 90 degrees and 105 degrees). The polarization maintaining degree of the polarization maintaining prism film is 98%.

The invention provides a polarization maintaining prism film, wherein a first structural layer is a prism layer PL (prism layer), and a second structural layer is an atomized layer. The thickness T of the substrate layer is 250 mu m, the polarization-maintaining substrate layer is made of PC (polycarbonate), the optical isotropy is realized, the polarization maintaining degree is more than 99%, the prism layer is made of transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the bottom sides of the triangles are 50 micrometers, and the vertex angles are 90 degrees. The haze of the atomization layer is 5% -30%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining degree of the polarization maintaining prism film is 95% -97%.

Further, the present invention provides a polarization maintaining inverse prism film, wherein the first structural layer is absent, and the second structural layer is an inverse prism layer RL (reverse-prism layer). The thickness T of the matrix layer is 25-250 μm, the polarization-maintaining matrix layer is made of PC, TAC, PMMA or COP, the optical isotropy is realized, the polarization maintaining degree is greater than 99%, the reverse prism layer is made of a transparent polymer resin AR, PC or PMMA, and the refractive index nd of the transparent polymer resin is 1.5-1.65 (such as 1.5, 1.55 or 1.65). The inverted prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles or common triangles, the width L of the bottom edge of each triangle is 10-100 mu m (such as 10-20 mu m, 50-100 mu m), the vertex angle theta is selected from 40-90 degrees (such as 40 degrees, 60 degrees, 80 degrees or 90 degrees), one larger bottom angle alpha is 90-0.5 theta + gamma, and the deflection angle gamma is 0-10 degrees. The polarization maintaining degree of the polarization maintaining inverse prism film is 98%.

The invention provides a polarization-maintaining inverse prism film, wherein a first structural layer is an atomized layer, and a second structural layer is an inverse prism layer RL (reverse-prism layer). The thickness T of the substrate layer is 250 mu m, the polarization-maintaining substrate layer is made of PC (polycarbonate), the optical isotropy is realized, the polarization maintaining degree is more than 99%, the inverse prism layer is made of a transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The inverted prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the width L of the bottom edge of each triangle is 50 mu m, the vertex angle theta is selected from 60 degrees, one larger bottom angle alpha is 90-0.5 theta + gamma, and the deflection angle gamma is 0 deg. The haze of the atomization layer is 30% -60%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining degree of the polarization maintaining prism film is 90% -95%.

The invention also provides a preparation method of the polarization-maintaining optical film, wherein the resin or the resin formula containing particles is respectively prepared into a first structural layer or a second structural layer on the front surface/the back surface of the polarization-maintaining matrix layer by sequentially utilizing the processes of coating, micro-replication or hot press molding; the coating is suitable for preparing an atomizing layer of a polarization-maintaining diffusion film, and the micro-replication and hot press molding are suitable for preparing the atomizing layer, the micro-lens layer and the prism layer of the polarization-maintaining diffusion film, the polarization-maintaining micro-lens film, the polarization-maintaining prism film and the polarization-maintaining inverse prism film.

Further, the preparation method of the polarization-maintaining optical film comprises the following steps:

(1) coating a first structural layer on the front surface of the polarization-maintaining base layer serving as a supporting layer to obtain a polarization-maintaining optical film containing the first structural layer;

(1) a mold roll (roll 1) for producing a first structural layer;

(2) using the polarization-maintaining matrix layer as a supporting layer, and performing micro-replication or hot-press molding on the front surface by using a roller 1 to obtain a first structural layer (convex) to obtain a polarization-maintaining optical film containing the first structural layer;

(1) taking the polarization-maintaining matrix layer as a supporting layer, and coating a second structural layer on the back surface to obtain a polarization-maintaining optical film containing the second structural layer;

(1) preparing a mould roller (roller 2) of the second structural layer;

(2) taking the polarization-maintaining matrix layer as a supporting layer, and utilizing a roller 2 to micro-copy or hot-press molding a second structural layer on the back surface to obtain a polarization-maintaining optical film containing the second structural layer; (ii) a

(1) coating a first structural layer on the front surface of the polarization-maintaining base layer serving as a supporting layer to obtain a semi-finished product containing the first structural layer;

(2) coating a second structural layer on the back of the semi-finished product prepared in the step (1) to obtain a polarization maintaining optical film simultaneously containing the first structural layer and the second structural layer;

(1) a mold roll (roll 1) for producing a first structural layer;

(2) utilizing a mold roller to micro-copy or hot-press and form a first structural layer on the front surface of the polarization-preserving matrix layer to obtain a semi-finished product containing the first structural layer;

(3) preparing a mould roller (roller 2) of the second structural layer;

(4) utilizing a roller 2 to micro-copy or hot-press and form a second structural layer on the back of the polarization-maintaining matrix layer to obtain a polarization-maintaining optical film simultaneously containing the first structural layer and the second structural layer;

it should be noted that the processing manner of the first structural layer and the second structural layer should be selected according to the type of the structural layer and the type of the material, and the invention is not preferred;

it should be noted that the method for preparing the polarization-maintaining optical film provided by the invention is suitable for the production of sheets and is also suitable for the production of coiled materials.

The polarization-maintaining optical film can be used as an optical functional material for an optical system needing polarization maintaining. The polarization maintaining optical film is particularly suitable for an LCD linear polarization backlight source, and can maintain higher polarization degree when linearly polarized light in the backlight passes through the polarization maintaining optical film, so that the final high transmittance of a polarizer under the LCD is ensured, and the utilization rate of the backlight source is greatly improved.

Compared with the prior art, the polarization-maintaining optical film provided by the invention can be matched with a linearly polarized light source, a linearly polarized backlight source can be conveniently generated, a reflection-type polarizer with a complex process and a high price is not needed, the high transmittance of the polarizer under an LCD can be ensured, the utilization rate of the backlight source is improved, the performance-price ratio of a synergistic scheme is higher, and the advantages are obvious.

It was found that the rotation angle of the prism film in the backlight has some influence on the polarization-maintaining degree: 1. when the included angle between the prism rib and the transmission axis of the polaroid is 0 degree, the polarization maintaining degree is highest; 2. with the increase of the angle, the polarization maintaining degree is continuously reduced, and reaches a minimum value at 45 degrees; 3. then continuously rising, and the 90-degree polarization maintaining degree is close to the 0-degree polarization maintaining degree. Therefore, it is desirable to avoid prism ribs in polarization maintaining prism films from being forced to corner cut by interference cancellation. Therefore, it is considered to develop a polarization maintaining prism film capable of resolving interference without requiring a corner or a very small corner.

The invention provides a de-interference polarization-maintaining prism film which comprises a polarization-maintaining base layer, a first structural layer and a second structural layer, wherein the first structural layer is a prism layer and is positioned on the upper surface of the base layer, and the second structural layer is absent or is an atomizing layer and is positioned on the lower surface of the base layer. The prism layer is formed by tiling a plurality of same or different prism ribs. The triangular prism ribs are shaken left and right in the longitudinal direction.

The cross section of the triangular prism rib is an isosceles triangle.

The ridgeline (the peak point is along the longitudinal trajectory) of the triangular prism rib is a free curve of left-right jitter variation, and the jitter amplitude V (the horizontal distance between the leftmost side and the rightmost side) is 1-10 μm, preferably 2-4 μm.

The dither amplitude is smaller than the base width W of the narrowest triangular prism rib in the lateral period_min。

The base of the triangle is any t of 10-100 mu m, t is selected from any integer between 1-7, and is preferably 2 or 3;

the vertex angle of the triangle is any k in 75-105 degrees, k is selected from any integer between 1-7, and is preferably 2 or 3;

the cross section of the prism layer is any combination of different triangles.

The prism layer has a lateral period (width of a cross-sectional repeating unit) of 50 to 2000 [ mu ] m. In the same period, the types t and the vertex angles k of the bottom edges can be selected from 1 to 7 respectively, and the types are preferably 2 to 3 respectively.

The haze of the atomization layer is 5-30%.

The prism layer is composed of a transparent polymer resin AR having a refractive index nd of 1.55.

The haze of the atomization layer is 5% -30%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5.

Furthermore, the base layer of the interference-free polarization-maintaining prism film is made of PC, the thickness T is 250 μm, the prism layer is made of AR, and the refractive index is 1.55.

Further, the length of the base of the triangle of the cross section of the triangular prism rib is at least 2, and further, the angle of the apex angle of the triangle of the cross section of the triangular prism rib is at least 2.

The base of the triangle is any t of 10-100 mu m, and t is selected from 2-7, preferably 2-3;

the vertex angle of the triangle is any k in 75-105 degrees, and k is selected from 2-7, preferably 2-3;

the triangular prism ribs include triangular prism ribs having different structures.

The triangular prism ribs have 2-7 structures.

Further, the bottom sides of the triangles are any t types of 10-100 micrometers, t is 2, the vertex angles of the triangles are any k types of 75-105 degrees, and k is 2; the prism layer is formed by tiling a prism rib, and the prism rib has a first structure and a second structure. The first structure and the second structure form a cycle. The prism layer includes a number of periods. The dither amplitude V is 1-10 μm.

Further, the prism layer is formed by tiling the triangular prism rib, the triangular prism rib has first structure and second structure. The first structure and the second structure form a cycle. The prism layer includes a number of periods. The length of the bottom side of a triangle of the cross section of the first structural triangular prism rib is 50 micrometers, the angle of a vertex angle is 90 degrees, and the number of the vertex angles in one period is 1; the length of the base of the triangle of the cross section of the second triangular prism rib is 40 μm, the angle of the apex angle is 105 °, and the number in one period is 1. That is, one period includes 1 first structure and 1 second structure, and the prism layer is alternately arranged by the first structures and the second structures. The length of each period is 100 μm. The dither amplitude V of the triangular prism rib is 10 μm. The foregoing technical solution includes example 65.

Further, the prism layer is formed by tiling the triangular prism rib, the triangular prism rib has first structure and second structure. The first structure and the second structure form a cycle. The prism layer includes a number of periods. The length of the bottom side of a triangle of the cross section of the first structural triangular prism rib is 50 mu m, the angle of a vertex angle is 90 degrees, and the number of the vertex angles in one period is 1 or 2; the length of the base of the triangle of the cross section of the second triangular prism rib is 40 or 50 μm, the angle of the apex angle is 75-100 °, and the number in one period is 2, 4, 8, 19 or 38. That is, one cycle includes 1 or 2 first structures and 2 to 38 second structures. The length of each period is 150-2000 μm. The triangular prism ribs have a dither amplitude V of 1-8 μm (e.g., 1 μm, 2 μm, 4 μm, 6 μm, or 8 μm). The foregoing technical solutions include examples 66 to 70.

Further, the bottom sides of the triangles are any t in the range of 10-100 micrometers, t is 3, the vertex angles of the triangles are any k in the range of 75-105 degrees, and k is 3; the prism layer is formed by tiling a prism rib, and the prism rib has first structure, second structure and third structure. The first structure, the second structure, and the third structure form a cycle. The prism layer includes a number of periods. The dither amplitude V of the triangular prism ribs is 2-4 μm.

Further, the prism layer is formed by tiling the triangular prism rib, the triangular prism rib has first structure, second structure and third structure. The first structure, the second structure, and the third structure form a cycle. The prism layer includes a number of periods. The length of the base of the triangle of the cross section of the first structural triangular prism rib is 20 to 90 μm (e.g., 20 μm, 50 μm, 60 μm, or 90 μm), the angle of the apex is 90 °, and the number in one period is 1 to 5 (e.g., 1, 2, or 5); the triangle of the cross section of the second structural triangular prism rib has a length of a base of 30 to 70 μm (e.g., 30 μm, 40 μm, 50 μm, 60 μm, or 70 μm), an angle of a vertex of 95 to 105 ° (e.g., 95 °, 100 °, or 105 °), and the number in one period is 1 to 4, e.g., 1, 2, or 4. The length of the base of the triangle of the cross section of the third structural triangular prism rib is 10 to 100 μm (e.g., 10 μm, 40 μm, 50 μm, 80 μm, or 100 μm), the angle of the apex is 75 to 85 ° (e.g., 75 °, 80 °, or 85 °), and the number in one period is 1 to 3, e.g., 1, 2, or 3. That is, one cycle includes 1 to 5 (e.g., 1, 2, or 5) first structures, 1 to 4 (1, 2, or 4) second structures, and 1 to 3 (e.g., 1, 2, or 3) third structures. The length of each period is 150-1030 μm. The dither amplitude V of the triangular prism ribs is 2-4 μm (e.g., 2 μm or 4 μm). The foregoing technical solutions include examples 71 to 80.

Furthermore, the prism layer is formed by tiling a triple prism rib, and the triple prism rib has first structure, second structure, third structure, fourth structure, fifth structure, sixth structure and seventh structure. The first structure, the second structure, the third structure, the fourth structure, the fifth structure, the sixth structure and the seventh structure form a cycle. The prism layer includes a number of periods. The dither amplitude V of the triangular prism rib is 2 μm.

Further, the prism layer is formed by tiling the prism rib, and the base number t of prism rib is 7, and angle k is 1, and the base of first structure to seventh structure is 35/40/45/50/55/60/65 mu m respectively, and the apex angle is 90, and the structure quantity is 1, and the sequencing divide into 1/2/7/4/5/3/6. The dither amplitude V of the triangular prism rib is 2 μm.

Further, the prism layer is formed by tiling prism ribs, the base number t of prism ribs is 1, angle k is 7, the base of first structure to seventh structure is 50 μm, the apex angle is 75/80/85/90/95/100/105 respectively, the structure number is 1, the ordering is 1/6/5/4/3/2/7. The dither amplitude V of the triangular prism rib is 2 μm.

The polarization maintaining degree of the polarization maintaining prism film is 96% -98%.

When linearly polarized light passes through the polarization maintaining prism film, the polarization maintaining prism film has polarization maintaining degree greater than or equal to 95% to incident linearly polarized light.

Further, when linearly polarized light in the LCD backlight passes through the polarization maintaining prism film, the polarized incident light may retain a higher polarization degree, and the polarization maintaining degree is greater than or equal to 95%. Thereby ensuring the final high transmission of the polarizer under the LCD and greatly improving the utilization rate of the backlight source.

The preparation method of the polarization maintaining prism film comprises the following steps:

(1) preparing a mold roller of the prism layer;

(2) and (3) taking the polarization-maintaining base layer as a supporting layer, and preparing a prism layer on the front surface by using a die roller through UV transfer printing to obtain the polarization-maintaining prism film only comprising the prism layer on the front surface.

Further, the preparation method of the polarization maintaining prism film comprises the following steps:

(1) taking the polarization-maintaining matrix layer as a supporting layer, and coating an atomizing layer on the back surface to obtain a polarization-maintaining back-coating semi-finished product containing the atomizing layer;

(2) preparing a mold roller of the prism layer;

(3) and preparing a prism layer on the front surface of the polarization-maintaining back-coated semi-finished product (namely the front surface of the polarization-maintaining base layer) by using a mold roller through UV transfer printing to obtain the polarization-maintaining prism film simultaneously containing the back atomized layer and the front prism layer.

The polarization-maintaining prism film provided by the invention can simultaneously realize the optical characteristics of interference elimination and high polarization-maintaining degree, and when linearly polarized light in LCD backlight passes through the interference elimination polarization-maintaining prism film, higher incident light polarization degree can be kept, and the polarization-maintaining degree is not less than 96%, so that the final high transmittance of a polarizer under the LCD is ensured, and the utilization rate of a backlight source is further improved.

Drawings

FIG. 1 illustrates the reason for the low light utilization efficiency of LCD;

FIG. 2 is a schematic diagram of a conventional synergy scheme for an LCD;

FIG. 3 is a schematic diagram of a novel synergy scheme for an LCD;

FIG. 4 is a schematic diagram of the depolarization result of a conventional optical film in a novel synergistic optical path;

FIG. 5 is a schematic diagram illustrating the polarization maintaining effect of the polarization maintaining optical film according to the present invention;

FIG. 6 is a schematic diagram of a method for measuring polarization maintaining degree;

FIG. 7 is a schematic diagram of the basic structure of a polarization maintaining optical film;

FIG. 8a is a schematic diagram of the basic structure of a de-interference polarization maintaining prism film without a rear matte layer according to the present invention;

FIG. 8b is a schematic diagram of the basic structure of a de-interference polarization maintaining prism film according to the present invention, including a rear matte layer;

FIG. 9 is a top view (horizontal wobble structure) of a de-interference polarization maintaining prism film of the present invention.

Wherein:

11: an upper polarizer; 12: a liquid crystal panel (including a glass substrate, an optical filter, a liquid crystal layer, a thin film transistor, and the like); 13: a lower polarizer; 14: a backlight module; 15: a reflective polarizer;

21: partially polarized light; 22: linearly polarized light in a parallel direction (relative to the transmission axis of the lower polarizer or the paper surface); 23: linearly polarized light in the vertical direction (relative to the transmission axis of the lower polarizer or the paper surface);

3: a conventional optical film;

4: a polarization maintaining optical film;

50: a polarization maintaining substrate layer; 51: a first structural layer; 52: a second structural layer;

54: a particle-free matte layer; 57: a prism layer (the prism rib is of a horizontal shaking structure);

57 a: a peak of the horizontal dither structure; 57 b: a trough of the horizontal dither structure;

60: a diaphragm to be tested; 61: a polarizer; 62: a parallel analyzer (parallel to the polarizer for detecting Imax); 63: a vertical analyzer (perpendicular to the polarizer, detect Imin).

Detailed Description

In order to make the structure and features of the invention easier to understand, preferred embodiments of the invention will be described in detail below with reference to the drawings.

The invention provides a polarization-maintaining optical film (4), the polarization-maintaining optical film (4) is used for replacing a traditional optical film (3) in fig. 4, and as shown in fig. 5, after linearly polarized light (22) in the horizontal direction passes through the polarization-maintaining optical film (4), emergent light is kept to be the linearly polarized light (22) in the horizontal direction.

The properties of the polarization-maintaining optical film provided by the present invention were evaluated in the following manner.

(A) Degree of deviation of the protection

As shown in fig. 6, a film (60) to be measured is placed above a polarizer (polarizer) (61) and below a parallel analyzer (polarizer) 62 or a vertical analyzer (polarizer) 63, and the intensity of the outgoing light is measured. When the analyzer angle is parallel to the linearly polarized light, the analyzer is called a parallel analyzer, and the light intensity is called Imax, when the analyzer angle is perpendicular to the linearly polarized light, the analyzer is called a perpendicular analyzer, and the light intensity is called Imin.

As shown in fig. 7, the present invention provides a polarization maintaining optical film, which includes a first structural layer 51, a polarization maintaining substrate layer 50 and a second structural layer 52, wherein the first structural layer is located on the upper surface of the polarization maintaining substrate layer 50, and the second structural layer is located on the lower surface of the polarization maintaining substrate layer 50.

Example 1

The invention provides a polarization-maintaining optical film, as shown in fig. 7, the polarization-maintaining optical film is a polarization-maintaining diffusion film, the first structural layer 51 is a matte layer dl (diffusion layer), and the second structural layer 52 is not present. The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC, and has optical isotropy and polarization maintaining degree of > 99%, and the haze of the polarization-maintaining diffusion film is 98%. The haze of the first atomization layer is 98%, the type of the atomization layer is a particle coating, the particle coating is composed of transparent polymer resin PU and transparent polymer particles PMMA, the particle size d is 5-15 micrometers, and the refractive index na of the transparent polymer resin is 1.5. The polarization maintaining diffusion film has a polarization maintaining degree of 82%.

Example 2

As shown in fig. 7, the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining base layer 50, and a second structural layer 52, wherein the first structural layer is located on the upper surface of the base layer 50, the second structural layer is located on the lower surface of the base layer 50, the polarization maintaining optical film is a polarization maintaining diffusion film, the first structural layer 51 is an matte layer, and the second structural layer 52 is a matte layer. The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC, and has optical isotropy and polarization maintaining degree of > 99%, and the haze of the polarization-maintaining diffusion film is 98%. The haze of the first atomization layer is 98%, the type of the atomization layer is a particle coating, the particle coating is composed of transparent polymer resin PU and transparent polymer particles PMMA, the particle size d is 5-15 micrometers, and the refractive index na of the transparent polymer resin is 1.5. The haze of the second matte layer is 5%, the matte layer is a particle-free coating and is composed of a transparent polymer resin AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining diffusion film has a polarization maintaining degree of 80%.

Examples 3 to 20

The polarization-maintaining diffusion film provided in example 1, wherein the other parameters are listed in table 1.

TABLE 1 design parameters and optical Properties of polarization-maintaining diffusion films provided in examples 1-20

Note 1: t is the thickness of the polarization maintaining base layer.

As shown in table 1, examples of the polarization-maintaining diffusion films with different material and design parameter combinations are shown. It can be found that when the substrate layer is made of the polarization-maintaining substrate such as PC, PMMA, TAC, COP, the polarization-maintaining diffusion film prepared has a polarization-maintaining degree of more than 80%, and the thickness T has little influence. When the haze of the atomized layer is reduced, the polarization retention is improved, and the influence of the type, resin and particle material of the atomized layer is not great. When the second structural layer is the low-haze atomization layer, the anti-sticking and anti-scraping effects can be achieved, and the optical influence is small.

Example 21

Fig. 7 shows that the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining microlens film, the first structural layer 51 is a microlens array layer ml (microlens layer), and the second structural layer 52 does not exist. The thickness T of the substrate layer 50 is 250 mu m, the polarization-maintaining substrate layer is made of PC, the optical isotropy is achieved, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining micro-lens film is 96%. The haze of the microlens array layer was 98%, the microlens array layer was formed of a transparent polymer resin AR having a refractive index nc of 1.5. In the microlens array layer, the distance D between the main optical axes of adjacent microlenses is 50 μm, the width of each microlens is W (W is D), the height of each microlens is H, the aspect ratio H/W is 0.5, and at this time, each microlens is hemispherical; the polarization maintaining degree of the polarization maintaining micro lens is 85%.

Example 22

Fig. 7 shows a polarization maintaining optical film provided by the present invention, which includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, wherein the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining microlens film, the first structural layer 51 is a microlens array layer, and the second structural layer 52 is an atomizing layer. The thickness T of the substrate layer 50 is 250 mu m, the polarization-maintaining substrate layer is made of PC, the optical isotropy is achieved, the polarization maintaining degree is greater than 99%, and the haze of the polarization-maintaining micro-lens film is 96%. The haze of the microlens array layer is 98%, the microlens array layer is composed of a transparent polymer resin AR, and the refractive index nc of the transparent polymer resin is 1.5. The haze of the atomization layer is 5%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining micro-lens film has 85% polarization maintaining degree.

Examples 23 to 36

The polarization maintaining microlens film as provided in example 21, wherein the other parameters are listed in table 2.

TABLE 2 design parameters and optical Properties of examples 21-36

Note 1: t is the thickness of the base layer; d is the distance between the main optical axes of the adjacent micro lenses; w is the width of the micro-lens, H is the height of the micro-lens, and H/W is the aspect ratio.

As shown in Table 2, examples of polarization maintaining microlens films with different material and design parameter combinations are provided. It can be found that when the substrate layer is made of the polarization-maintaining substrate such as PC, PMMA, TAC, COP, the polarization-maintaining microlens films obtained have polarization maintaining degrees of more than 80%, and the thickness T has little influence. When the haze of the microlens layer is reduced, the polarization maintaining degree is improved, and when the refractive index of the transparent polymer is reduced, or the aspect ratio is reduced, the haze is also reduced, the polarization maintaining degree is also improved, and the influence of the kind of the resin is not great. When the second structural layer is the low-haze atomization layer, the anti-sticking and anti-scraping effects can be achieved, and the optical influence is small.

Example 37

As shown in fig. 7, the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining prism film, the first structural layer 51 is a prism layer pl (prism layer), and the second structural layer 52 is not present. The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC (polycarbonate), the material is optically isotropic, the polarization maintaining degree is greater than 99%, the prism layer is made of a transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the bottom sides of the triangles are 50 micrometers, and the vertex angles are 90 degrees. The polarization maintaining degree of the polarization maintaining prism film is 98%.

Example 38

As shown in fig. 7, the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining prism film, the first structural layer 51 is a prism layer pl (prism layer), and the second structural layer 52 is an matte layer. The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC (polycarbonate), the material is optically isotropic, the polarization maintaining degree is greater than 99%, the prism layer is made of a transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the bottom sides of the triangles are 50 micrometers, and the vertex angles are 90 degrees. The haze of the atomization layer is 5%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining degree of the polarization maintaining prism film is 97%.

Examples 39 to 50

The polarization maintaining prism film provided in example 37, wherein the other parameters are listed in table 3.

TABLE 3 design parameters and optical Properties of examples 37-50

Note 1: t is the thickness of the base layer.

As shown in table 3, examples of polarization maintaining prism films with different material and design parameters are provided. It can be found that when the substrate layer is made of the polarization-maintaining substrate such as PC, PMMA, TAC, COP, the polarization-maintaining prism films prepared by the method have polarization-maintaining degree of more than 80% and the thickness T has little influence. When the material, the refractive index, the bottom edge and the top angle of the prism layer are changed, the polarization maintaining degree is basically not influenced. When the second structural layer is an atomizing layer, the effects of adhesion prevention and scratch resistance can be achieved, and when the haze is increased, the polarization degree is slightly reduced.

Example 51

As shown in fig. 7, the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining inverse prism film, the first structural layer 51 does not exist, and the second structural layer 52 is an inverse prism layer RL (reverse-prism layer). The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC (polycarbonate), the optical isotropy is achieved, the polarization maintaining degree is greater than 99%, the inverse prism layer is made of a transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The inverted prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles or common triangles, the width L of the bottom edge of each triangle is 50 micrometers, the vertex angle theta is selected from 60 degrees, one larger bottom angle alpha is 90 degrees to 0.5 theta + gamma, and the deflection angle gamma is 0 degree. The polarization maintaining degree of the polarization maintaining inverse prism film is 98%.

Example 52

As shown in fig. 7, the polarization maintaining optical film provided by the present invention includes a first structural layer 51, a polarization maintaining substrate layer 50, and a second structural layer 52, the first structural layer is located on the upper surface of the substrate layer 50, the second structural layer is located on the lower surface of the substrate layer 50, the polarization maintaining optical film is a polarization maintaining inverse prism film, the first structural layer 51 is an matte layer, and the second structural layer 52 is an inverse prism layer RL (reverse-prism layer). The thickness T of the substrate layer 50 is 250 μm, the polarization-maintaining substrate layer is made of PC (polycarbonate), the optical isotropy is achieved, the polarization maintaining degree is greater than 99%, the inverse prism layer is made of a transparent polymer resin AR, and the refractive index nd of the transparent polymer resin is 1.55. The inverted prism layer is formed by tiling triangular prism ribs, the cross sections of the triangular prism ribs are isosceles triangles, the width L of the bottom edge of each triangle is 50 mu m, the vertex angle theta is selected from 60 degrees, one larger bottom angle alpha is 90-0.5 theta + gamma, and the deflection angle gamma is 0 deg. The haze of the atomization layer is 30%, the type of the atomization layer is a particle-free coating and is composed of a transparent polymer AR, and the refractive index nb of the transparent polymer resin is 1.5. The polarization maintaining degree of the polarization maintaining prism film is 95%.

Examples 53 to 64

The polarization maintaining and reverse prism film provided in example 51, wherein the other parameters are listed in table 4.

TABLE 4 design parameters and optical Properties of examples 51-64

Note 1: t is the thickness of the base layer.

As shown in table 4, examples of polarization-maintaining inverse prism films with different material and design parameters are provided. It can be found that when the substrate layer is made of the polarization-maintaining substrate such as PC, PMMA, TAC, COP, the polarization-maintaining degree of the prepared polarization-maintaining inverse prism film is more than 80%, and the thickness T has little influence. When the material, the refractive index, the bottom edge and the top angle of the inverse prism layer are changed, the polarization maintaining degree is basically not influenced. When the first structural layer is an atomized layer, the effects of adhesion resistance and scratch resistance can be achieved, and when the haze is increased, the polarization degree is slightly reduced.

Examples 65 to 82

In example 37, the polarization maintaining prism film according to examples 65-82 (as shown in FIG. 9 in the top view) has a substrate layer made of PC, a thickness T of 250 μm, a prism layer made of AR, and a refractive index of 1.55. Examples 37 and 65 have no rear matte layer (as shown in fig. 8 a), examples 66 to 80 have a matte layer on the rear surface (as shown in fig. 8 b), the matte layer is a particle-free coating, the haze is 30%, the coating resin material is AR, and the refractive index is 1.5. The polarization maintaining degrees of the examples 37 and 65 are 98%, and the polarization maintaining degrees of the examples 66 to 82 are 96%. The other prism layer structure design parameters of examples 37, 65-80 are listed in Table 5. The prism structure of example 81 was designed such that the number of the base lines t was 7, the angle k was 1, the base lines of the first to seventh structures were 35/40/45/50/55/60/65 μm, the apex angles were 90 °, the number of the structures was 1, and the ranking was 1/2/7/4/5/3/6. The dither amplitude V of the triangular prism rib is 2 μm. The prism structure of example 82 was designed such that the number of the base lines t was 1, the angle k was 7, the base lines of the first to seventh structures were 50 μm, the apex angles were 75/80/85/90/95/100/105 °, the number of the structures was 1, and the ranking was 1/6/5/4/3/2/7. The dither amplitude V of the triangular prism rib is 2 μm.

TABLE 5 prism layer design parameters for examples 37, 65-80 polarization maintaining prism films

Note 1: the sequence indicates the arrangement order of the first structure, the second structure or the third structure from left to right in the whole period.

With comparative examples 37 and 65, and comparative examples 66 to 82, the polarization maintaining degree of the polarization maintaining prism film had substantially no effect when only the prism structure layer design was changed. The interference-eliminating polarization-preserving prism film is obtained by matching the vertex angle and the bottom edge of the prism structure (with a triangular section) and carrying out a design of horizontal jitter to a certain degree, and the optical characteristics of interference elimination and high polarization-preserving degree can be realized simultaneously. In the same period, the types t and the vertex angle k of the bottom edge can be selected from 1 to 7, 2 to 3 are preferred, less than 2 types of solution interference is weak, more than 3 types of cutters are available, and the processing cost is high. When the structure collocation is simple, a larger jitter amplitude, such as 4-10 μm, can be collocated, and when the structure collocation is complex, a smaller jitter amplitude, such as 1-4 μm, can be collocated. When the shaking amplitude is less than 2 micrometers, the film surface is fine and smooth but the interference eliminating effect is weak, and when the shaking amplitude is more than 4 micrometers, the interference eliminating effect is strong but the film surface is rough, and the preferred range is 2-4 micrometers. It should be noted that the amplitude of the horizontal dither should also be less than the base width W of the smallest prism rib in the periodic structure_minOtherwise, the prism ribs may be staggered, which is disadvantageous to the appearance.

It should be noted that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention. All equivalent changes and modifications made according to the disclosure of the present invention are covered by the scope of the claims of the present invention.

Claims

1. The polarization-maintaining optical film is characterized by comprising a polarization-maintaining base layer, a first structural layer and/or a second structural layer, wherein the first structural layer is positioned on the upper surface of the polarization-maintaining base layer, and the second structural layer is positioned on the lower surface of the polarization-maintaining base layer; when linearly polarized light passes through the polarization-maintaining optical film, the polarization-maintaining optical film has a polarization maintaining degree of greater than or equal to 80% for incident linearly polarized light.

2. The polarization maintaining optical film of claim 1, wherein the polarization maintaining optical film is a polarization maintaining prism film, the first structural layer of the polarization maintaining prism film is a prism layer, and the second structural layer is absent or is a matte layer; the prism layer is formed by tiling prism ribs, the cross sections of the prism ribs are isosceles triangles, the bottom edges of the triangles are 10-100 mu m, and the vertex angles are 75-105 degrees; the haze of the atomization layer is 0-30%.

3. The interference-relieving polarization-maintaining prism film is characterized by comprising a polarization-maintaining base layer, a first structural layer and a second structural layer, wherein the first structural layer is a prism layer and is positioned on the upper surface of the base layer, and the second structural layer is absent or is an atomized layer and is positioned on the lower surface of the base layer; the prism layer is formed by tiling a plurality of same or different prism ribs; the triangular prism ribs are shaken left and right in the longitudinal direction.

4. The de-interference polarization-preserving prism film according to claim 3, wherein the triangular prism ribs have a cross section of an isosceles triangle shape; the ridgeline of the triangular prism rib is a free curve with left-right shaking change, and the shaking amplitude V is 1-10 mu m.

5. The de-interference polarization maintaining prism film according to claim 4, wherein the dither amplitude V is 2-4 μm.

6. The film according to claim 3, wherein the base of the triangle is any t of 10-100 μm, and t is selected from any integer between 1-7; the vertex angle of the triangle is any k in 75-105 degrees, and k is selected from any integer between 1-7.

7. The de-interference polarization-preserving prism film according to claim 3, wherein the cross section of the prism layer is any combination of different triangles; the transverse period of the prism layer is 50-2000 mu m; in the same period, the types t and k of the bottom edges can be selected from 1 to 7 respectively.

8. The interferometer polarization maintaining prism film of claim 3, wherein the length of the base of the triangle of the cross section of the triangular prism rib is at least 2, and the angle of the apex of the triangle of the cross section of the triangular prism rib is at least 2.

9. The film according to claim 6, wherein the base of the triangle is any t of 10 to 100 μm, t is 2, the apex angle of the triangle is any k of 75 to 105 °, k is 2; the prism layer is formed by tiling prism ribs, and each prism rib is provided with a first structure and a second structure; the first structure and the second structure form a period, and the prism layer comprises a plurality of periods; the dither amplitude V of the triangular prism ribs is 1-10 μm.

10. The film according to claim 6, wherein the base of the triangle is any t of 10 to 100 μm, t is 3, the apex angle of the triangle is any k of 75 to 105 °, and k is 3; the prism layer is formed by tiling prism ribs, and each prism rib is provided with a first structure, a second structure and a third structure; the first structure, the second structure and the third structure form a period, and the prism layer comprises a plurality of periods; the dither amplitude V of the triangular prism ribs is 2-4 μm.