Optical compensation film, preparation method thereof, polaroid and display device

Abstract

The invention relates to an optical compensation film, a preparation method thereof, a polaroid and a display device. The optical compensation film comprises a liquid crystal compensation layer, a polymer alignment layer, a transparent electrode layer and a first base film layer. The optical compensation film provided by the invention adopts the rod-like liquid crystal compensation layer as an optical anisotropic layer, so that light generates phase delay of odd times of pi / 2, incident ray polarized light is changed into elliptically polarized light, and meanwhile, the birefringence of liquid crystal molecules is remarkably higher than that of a traditional polymer material, so that the thickness can be remarkably reduced; the polymer alignment layer is introduced, so that the liquid crystal can be anchored according to the specified direction of the polymer alignment layer so as to have orientation, and the optical anisotropy is enabled to run according to the design direction; the transparent electrode layer is introduced to assist the polymer alignment layer in anchoring the liquid crystal molecules, and the view angle can be expanded through multi-domain structure orientation. The overall thickness of the whole optical compensation film reaches 12250-14070 nm, and is reduced by 50-70% compared with the thickness of a traditional stretching type compensation film.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an optical compensation film and a preparation method thereof, as well as a polarizer and a display device. Background Art

[0002] In order to solve the problem of external light reflecting into the human eye and causing the display to be unable to be displayed, a special circular polarizer is usually used in self-luminous display panels (OLED / mini / micro-LED). The circular polarizer is used to reduce the external light reflected into the human eye. The circular polarizer is usually composed of a linear polarizer and an optical compensation film.

[0003] Traditional optical compensation films are composed of a base film, an optically anisotropic layer and an adhesive between the film layers. Currently, most optically anisotropic layers are made of stretched polymers. Due to the limitations of polymer materials and their own optical anisotropy in a narrow wavelength range, a multi-layer bonding method is usually required, which will result in a thicker optically anisotropic layer (approximately >30,000 nm), which does not meet the current trend of increasingly thin and light display products in the terminal market. Summary of the invention

[0004] The present application aims to provide an optical compensation film and a preparation method thereof, so that the overall thickness of the optical compensation film is reduced by more than 50% compared with the thickness of a traditional polymer stretched compensation film.

[0005] In a first aspect, an embodiment of the present application provides an optical compensation film, including a liquid crystal compensation layer, a polymer alignment layer and a transparent electrode layer;

[0006] The polymer alignment layer is arranged on one side of the liquid crystal compensation layer, and the transparent electrode layer is arranged on a side of the polymer alignment layer away from the liquid crystal compensation layer.

[0007] In certain embodiments of the present application, the thickness of the liquid crystal compensation layer is 700-2000 nm, the thickness of the polymer alignment layer is 50-70 nm, and the thickness of the transparent electrode layer is 800-1000 nm.

[0008] In some embodiments of the present application, the Δn of the liquid crystal molecules in the liquid crystal compensation layer is 0.1-0.3, where Δn is the difference between the refractive index of the liquid crystal molecules parallel to the optical axis and the refractive index perpendicular to the optical axis.

[0009] In some embodiments of the present application, a side of the transparent electrode layer close to the polymer alignment layer has a pattern.

[0010] In some embodiments of the present application, the pattern includes a multi-domain structure in which parallel grooves are arranged.

[0011] In some embodiments of the present application, the transparent electrode layer includes conductive glass.

[0012] In some embodiments of the present application, the liquid crystal compensation layer includes a chiral liquid crystal dopant.

[0013] In certain embodiments of the present application, the polymer alignment layer includes a polymer having a long-chain group, or a polymer having a long-chain group and a photosensitive group.

[0014] In certain embodiments of the present application, a bonding layer is further included, or a bonding layer and a second base film layer are included; the bonding layer is arranged on the other side of the liquid crystal compensation layer opposite to the polymer alignment layer, and the second base film layer is arranged on the side of the bonding layer away from the liquid crystal compensation layer.

[0015] In certain embodiments of the present application, the thickness of the bonding layer is 700-1000 nm, and the thickness of the first base film layer and the second base film layer is ≤5000 nm.

[0016] In a second aspect, the present application provides a method for preparing an optical compensation film, comprising:

[0017] The target material is sputtered to form a transparent electrode layer;

[0018] Applying a polymer material on the surface of the transparent electrode layer, and forming a polymer alignment layer after drying and curing;

[0019] The liquid crystal material is coated on the surface of the polymer alignment layer, and after drying and curing, a liquid crystal compensation layer is formed.

[0020] In certain embodiments of the present application, it also includes:

[0021] Curing the transparent slurry to form a first base film layer;

[0022] Performing target sputtering on the surface of the first base film layer to form a transparent electrode layer;

[0023] Applying a polymer material on the surface of the transparent electrode layer, and forming a polymer alignment layer after drying and curing;

[0024] Applying liquid crystal material on the surface of the polymer alignment layer, and forming a liquid crystal compensation layer after drying and curing;

[0025] An adhesive is coated on the surface of the liquid crystal compensation layer to form a bonding layer, and then a transparent slurry is cured on the surface of the bonding layer to form a second base film layer.

[0026] In a third aspect, an embodiment of the present application provides a polarizer, comprising a first polarizing layer protective layer, a polarizing layer, a second polarizing layer protective layer, an adhesive layer, and any one of the optical compensation films described in the present application;

[0027] The polarizer is disposed on one side of the first polarizing layer protective layer, and the polarizing layer, the second polarizing layer protective layer, the bonding layer and the optical compensation film are stacked in sequence in a direction gradually away from the first polarizing layer protective layer.

[0028] In a fourth aspect, an embodiment of the present application proposes a display device, comprising a display panel, a backlight module and any one of the polarizers described in the present application; the polarizers are respectively arranged on both sides of a glass substrate of the display panel, the polarizer on the light emitting side is an upper polarizer, and the polarizer on the light emitting side is a lower polarizer; the backlight module is arranged on the side of the lower polarizer away from the display panel.

[0029] The optical compensation film provided by the embodiment of the present application uses a rod-shaped liquid crystal compensation layer as an optical anisotropic layer, which causes light to produce a phase delay of an odd multiple of π / 2, and converts the incident linear polarized light into elliptically polarized light. At the same time, the birefringence of the liquid crystal molecules is significantly higher than that of traditional polymer materials, so that the thickness can be greatly reduced; in addition, the introduction of a polymer alignment layer on one side of the liquid crystal compensation layer allows the liquid crystal to be anchored in the direction specified by the polymer alignment layer so as to have orientation, ensuring that the optical anisotropy functions in the designed direction; and the introduction of a transparent electrode layer on the other side of the polymer alignment layer assists the polymer alignment layer in anchoring the liquid crystal molecules, and can be oriented through a patterned multi-domain structure to expand the viewing angle. The overall thickness of the entire optical compensation film is 12250-14070nm, which is 50-70% lower than the thickness of the traditional stretched compensation film. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The features, advantages and technical effects of the exemplary embodiments of the present application will be described below with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used for the same components. The accompanying drawings are not drawn according to the actual scale, but are only used to illustrate the relative position relationship. The layer thickness of some parts is exaggerated for easy understanding, and the layer thickness in the accompanying drawings does not represent the proportional relationship of the actual layer thickness.

[0031] Figure 1 A schematic diagram showing the structure of a conventional stretched optical compensation film is shown;

[0032] Figure 2 A schematic diagram showing the structure of an optical compensation film provided in a first embodiment;

[0033] Figure 3 The pattern shape of the transparent electrode layer is shown;

[0034] Figure 4 A schematic structural diagram of an optical compensation film provided in a second embodiment is shown;

[0035] Figure 5 A schematic structural diagram of a polarizer provided in the third embodiment is shown. DETAILED DESCRIPTION

[0036] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating examples of the present application. In the accompanying drawings and the following description, at least part of the known structures and technologies are not shown to avoid unnecessary ambiguity in the present application; and, for clarity, the size of the regional structure may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0037] Traditional optical compensation film (with Figure 1 ) is composed of a flexible base film plus an optical anisotropic layer (1 / 2λ and 1 / 4λ stretched compensation film) and a bonding layer formed by an adhesive between the film layers; most of the optical anisotropic layers of traditional optical compensation films are formed by stretching polymers. Due to the limitations of polymer materials and their own optical anisotropy in narrow wavebands, a multi-layer lamination method is usually required, which will result in a thicker optical anisotropic layer (about >30,000nm), which does not meet the current trend of increasingly thin and light display product terminals. The display panel provided by each embodiment is described in detail below in conjunction with the accompanying drawings.

[0038] First embodiment

[0039] like Figure 2 As shown, the optical compensation film provided in the first embodiment of the present application includes:

[0040] A liquid crystal compensation layer, a polymer alignment layer, a transparent electrode layer and a first base film layer;

[0041] The thickness of the liquid crystal compensation layer is 700-2000nm, which is related to the △n of the liquid crystal molecules. If the thickness is too small, the polarization conversion will fail and the brightness will be affected. If the thickness is too large, it will not meet the original intention of the present application to reduce the thickness of the optical compensation film. The △n of the liquid crystal molecules in the liquid crystal compensation layer is 0.1-0.3. △n is the difference between the refractive index of the liquid crystal molecules parallel to the optical axis and the refractive index perpendicular to the optical axis, which can also be called birefringence. Due to the difference in birefringence between liquid crystal and traditional polymer stretching materials, the birefringence of liquid crystal molecules is much higher than that of traditional polymer stretching materials (0.001~0.01), so the requirement for the thickness of the optical anisotropic layer is greatly reduced. Generally, the wavelength required for the display to act on the human eye is required to be in the range of 380~780nm, and the 1 / 4λ wave plate produces circular light, so the wavelength requirement range of the optical anisotropic layer is usually 95~195nm; taking the optical anisotropic layer requirement of 145nm as an example, based on the calculation formula of the delay amount △n×d, taking the minimum value of △n as 0.1, the thickness d of the liquid crystal compensation layer only needs to be 1.45μm, while the thickness of the traditional polymer stretching material is 14.5~145μm.

[0042] In the embodiment of the present application, the liquid crystal compensation layer can be formed by selecting liquid crystal molecules with long double bond side chains and terphenyl as the core, which are UV cured in the presence of an initiator. The liquid crystal molecule structure is as follows:

[0043]

[0044] Although the liquid crystal molecules are optically anisotropic materials, it is also necessary to allow the multiple liquid crystal molecules in the liquid crystal compensation layer to be arranged in a specified direction. Therefore, the polymer alignment layer is arranged on one side of the liquid crystal compensation layer to allow the liquid crystal molecules to be anchored in the specified direction of the polymer alignment layer. The thickness of the polymer alignment layer is 50-70nm. If the thickness is too small, the orientation range of the liquid crystal compensation layer will not be sufficiently affected, resulting in insufficient light effect of the liquid crystal compensation layer, resulting in reduced brightness. If the thickness is too large, it will have no effect on the functionality, but it is not conducive to the original intention of the present application to reduce the thickness of the optical compensation film. In addition, the traditional polymer stretching material is uniaxial / biaxially stretched. In order to make the light energy emit in the designed direction, it needs to be bonded at a specific angle, generally not an angle between 0 and 90°. Therefore, the utilization rate of the long roll material in the process cannot reach 100%. The liquid crystal coating can rely on the orientation of the polymer alignment layer and be presented on the film surface according to the given physical friction angle or UV light angle. Therefore, the utilization rate will be much higher than the optical anisotropic layer formed by the traditional polymer stretching material.

[0045] Among them, the polymer alignment layer can be formed by UV curing by selecting a polymer with long side chain groups, or a polymer with long chain groups and photosensitive groups; the former polymer uses physical friction to produce physical grooves in the polymer alignment layer, combined with the polymer long side chains to anchor the liquid crystal molecules, so that the liquid crystal molecules are arranged along the grooves with consistent direction; the latter, due to the additional photosensitive groups, can use light energy to break its chemical bonds to form chemical grooves and combine with long chain side chains to anchor the liquid crystal molecules, so that the liquid crystal molecules are arranged along the grooves with consistent direction.

[0046] In the embodiment of the present application, the polymer of the polymer alignment layer can be selected from polyimide polymers, which are divided into friction polyimide polymers and photosensitive polyimide polymers according to whether they have photosensitive groups; the friction polyimide polymer can be synthesized from a diamine with basic activity (having polymerization sites) and alignment (having long-chain groups) and a dianhydride with basic activity (having polymerization sites), and the photosensitive polyimide polymer has a diamine with basic activity (having polymerization sites), alignment (having long-chain groups) and photosensitivity (having photosensitive groups) and a dianhydride with basic activity (having polymerization sites); wherein the diamine includes but is not limited to p-phenylenediamine, 4,4'-diaminodiphenylmethane, cholesteryloxy-2,4-diaminobenzene, and 2-(methacrylate)ethyl-3,5-diaminobenzoic acid with photosensitive groups, etc., and the structural formula is as follows:

[0047]

[0048] Dianhydrides include but are not limited to cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,3-dimethylcyclobutanetetracarboxylic dianhydride, etc. The structural formula is as follows:

[0049]

[0050] The transparent electrode layer is arranged on the side of the polymer layer away from the liquid crystal compensation layer. The patterning of the transparent electrode layer can cooperate with the polymer film to anchor the liquid crystal sequence, and can also achieve multi-domain orientation to expand the viewing angle. The thickness is 800-1000nm. A thickness lower than this will affect the directional arrangement of the liquid crystal molecules, while a thickness higher than this will be detrimental to the original intention of the present application to reduce the thickness of the optical compensation film.

[0051] In the embodiment of the present application, the transparent electrode layer can be formed by target sputtering using transparent glass materials such as ITO or FTO. In the embodiment of the present application, if the liquid crystal molecules of the aforementioned liquid crystal compensation layer are selected from materials with △n close to 0.3, the layer thickness is relatively thin, and only a polymer alignment layer is required to affect the arrangement direction of the liquid crystal molecules from the overall film surface. In this case, the transparent electrode layer can be patterned accurately to anchor the liquid crystal sequence per unit area, that is, the side of the transparent electrode layer close to the polymer alignment layer has a pattern to assist the polymer film in anchoring the liquid crystal sequence; and if the liquid crystal molecules of the aforementioned liquid crystal compensation layer are selected from materials with △n close to 0.1, the layer thickness is relatively thick, and the polymer alignment layer is not enough to affect the entire liquid crystal compensation layer. It is necessary to add additional chiral liquid crystal dopants to the liquid crystal compensation layer to twist the direction of the liquid crystal optical axis by 90° for auxiliary alignment. In this case, the transparent electrode layer does not need to be patterned.

[0052] Preferably, the pattern is a multi-domain structure with parallel grooves, which can make the liquid crystal molecules multi-domain oriented, expand the viewing angle, and allow human eyes at different positions to receive the emitted light; the pattern of these multi-domain structures can be a dart shape or a 7° L / S (IPS pixel) structure in the same direction. For exemplary pattern drawings, see Figure 3 .

[0053] Second embodiment

[0054] like Figure 4 As shown, the optical compensation film provided in the second embodiment of the present application includes:

[0055] A second base film layer, a bonding layer, a liquid crystal compensation layer, a polymer alignment layer, a transparent electrode layer and a first base film layer;

[0056] The structure of the optical compensation film of the second embodiment of the present application includes the structure of the optical compensation film of the first embodiment, except that, in order to meet the production requirements of process technology, a first base film layer, a second base film layer and a bonding layer are added, and the material of the base film layer has the characteristics of heat resistance, chemical resistance, stability and easy peeling. The first base film layer is arranged on the side of the transparent electrode layer away from the liquid crystal compensation layer, the bonding layer is arranged on the other side of the liquid crystal compensation layer opposite to the polymer alignment layer, and the second base film layer is arranged on the side of the bonding layer away from the liquid crystal compensation layer.

[0057] The thickness of the adhesive layer is 700-1000nm. For adhesive layers with a thickness lower than this range, the film interface tension may be lower than 2.0kgf, and the polarizer used in downstream products may fall off or delaminate, resulting in a decrease in the yield of the optical compensation film. If the thickness is higher than this range, it is not conducive to the original intention of this application to reduce the thickness of the optical compensation film. The material of the adhesive layer can be a general adhesive, such as an acrylic adhesive.

[0058] The thickness of the first base film layer and the second base film layer is ≤5000nm. Theoretically, if the equipment and process are feasible, the thickness of the base film layer can be infinitely small but not 0, as long as it can be completely peeled off from the adjacent film layer. According to the actual process required, the current industry equipment can achieve a thickness of 3000-5000nm.

[0059] In the embodiment of the present application, considering the need for winding during processing, the first base film layer and the second base film layer are both made of transparent flexible materials, such as transparent flexible materials of polyimide, vinyl acetate, polyethylene terephthalate, etc.

[0060] Third embodiment

[0061] In the embodiment of the present application, a preparation method is proposed for the optical compensation film of the second embodiment, comprising:

[0062] (1) Preparation of flexible base film layer and transparent electrode layer

[0063] A transparent flexible slurry of polyimide, vinyl acetate, polyethylene terephthalate, etc. is selected, and it is coated on a glass substrate with a thickness of ≤5000nm and solidified as the first base film layer for sputtering of indium tin oxide target to form a transparent electrode ITO layer with a thickness of 1000nm. The ITO layer can be further processed according to the following two situations:

[0064] ① Perform photolithography to pattern ITO so that it can form an electric field drive for the planar arrangement of liquid crystal molecules. The ITO pattern is generally in the shape of a dart or 7° in the same direction L / S (IPS pixel structure). You can refer to Figure 3 pattern.

[0065] ② The ITO layer does not need to undergo a photolithography process to obtain a full-surface ITO layer with a film thickness of 1000nm.

[0066] (2) Preparation of polymer

[0067] ① Select diamine with basic activity, alignment and photosensitivity and basic activity dianhydride (such as cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, etc.) monomers and add them to solvent (such as NMP, GBL, BC, etc.) for polymerization to prepare polyimide polymers, distill and concentrate, then add solvent again to prepare photosensitive alignment liquid, which can make the liquid crystal within 0.5μm away from the film arranged in order;

[0068] ② Select basic active and aligning diamine and basic active dianhydride monomers (such as cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, etc.) and add solvents (such as NMP, GBL, BC, etc.) to polymerize to prepare polyimide polymers, distill and concentrate, and then add solvent again to prepare friction alignment liquid, which can make the liquid crystal within 0.5μm away from the film arranged in order;

[0069] (3) Preparation of liquid crystal materials

[0070] ① Select a single crystal with a long double-bond side chain with terphenyl as the core as a high refractive index single crystal, make its △n 0.2-0.3, add a liquid crystal polymer initiator (ratio 0.1-0.3%), and then mix with a solvent to make a liquid crystal material;

[0071] ② Select single crystals with long double-bond side chains with terphenyl as the core as high refractive index single crystals, so that its △n is 0.1-0.2, such as PGP-3-V single crystals and PGP-V-4 single crystals, add chiral dopants (ratio 0.15%-0.35%), liquid crystal polymer initiators (ratio 0.1-0.3%), and then mix with solvents to make liquid crystal materials;

[0072] (4) Selection of binder

[0073] Use general polarizer adhesive (acrylic series), the application thickness is 700-1000nm, and the performance requirement is that the film interface tension is greater than 2.0kgf;

[0074] (5) Preparation of optical compensation film

[0075] The glass substrate on which the first base film layer and the transparent electrode layer are formed in step (1) is peeled off by laser or chemical etching (HF), and the remaining first base film layer and the transparent electrode layer are wound on a roller.

[0076] The first base film layer and the transparent electrode layer are rolled up for coating of the polymer alignment liquid in step (2), and after drying (thickness is 50-70 nm), UV curing or rubbing is performed, and then the liquid crystal material is coated in step (3), dried (thickness is 700-2000 nm), and UV cured; and then rolled up.

[0077] The transparent electrode layer in step (1) and the liquid crystal material in step (3) may adopt one of the following corresponding relationships:

[0078] Step (1)-①ITO transparent electrode layer corresponds to step (3)-①liquid crystal material;

[0079] Step 1 (1)-②ITO transparent electrode layer corresponds to step (3)-②liquid crystal material;

[0080] There is no corresponding relationship between polymers, and polymers are randomly selected according to subsequent orientation methods, such as light and friction.

[0081] After the liquid crystal compensation layer is completed, the film is rolled out and an adhesive is coated (thickness is 700-1000nm) to form an adhesive layer. The same material in step (1) is used to attach a flexible base film and then UV-cured to form a second base film layer, completing the optical compensation film roll production process.

[0082] Fourth embodiment

[0083] In this application, a polarizer is also provided, see the structural diagram Figure 5 The polarizer is based on a conventional polarizer film architecture (excluding an optical compensation film), including the optical compensation film described in any of the aforementioned embodiments. The specific structure and function of the optical compensation film can be found in the relevant description of the optical compensation film provided in the above embodiments, and will not be repeated here.

[0084] In the present application, the polarizer includes a first polarizing layer protective layer, and a polarizing layer, a second polarizing layer protective layer, an adhesive layer and an optical compensation film involved in the present application that are gradually stacked away from the first polarizing layer protective layer. Among them, the first polarizing layer protective layer can use surface hardened triacetyl cellulose (HC TAC) as a protective film for the polarizing layer; the polarizing layer uses polyvinyl alcohol cellulose (PVA); the second polarizing layer protective layer uses triacetyl cellulose (TAC) as a protective film for the polarizing layer; the adhesive layer uses pressure-sensitive adhesive;

[0085] The optical compensation film prepared in the present application is rolled out, the second base film layer is laser peeled off, and the base film layer is bonded to the adhesive layer in the polarizer to obtain a liquid crystal coated optical compensation film type circular polarizer.

[0086] Fifth embodiment

[0087] In the present application, a display device is also provided, which includes a display panel, a backlight module and the polarizer involved in the present application. The polarizers are respectively arranged on both sides of the glass substrate of the display panel, the polarizer on the light-emitting side is the upper polarizer, and the polarizer on the light-emitting side is the lower polarizer; the backlight module is arranged on the side of the lower polarizer away from the display panel. The lower polarizer is used to convert the light beam generated by the backlight module into polarized light, and the upper polarizer is used to analyze the polarized light after being electrically modulated by the liquid crystal to generate light and dark contrast, thereby generating a display image.

[0088] The display panel may be any type of display panel currently known in the art, including but not limited to an OLED display panel.

[0089] It should be easily understood that “on,” “above,” and “over” in this application should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above something” or “over,” but also may include the meaning of “above something” or “over” with no intervening features or layers therebetween (i.e., directly on something).

[0090] As used herein, the term "layer" may refer to a portion of a material that includes an area having a certain thickness. A layer may extend over the entire underlying structure or overlying structure, or may have an extent that is smaller than the extent of the underlying or overlying structure. In addition, a layer may be an area of ​​a homogeneous or inhomogeneous continuous structure whose thickness is less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of the continuous structure or between any pairs of transverse planes at the top and bottom surfaces. A layer may extend laterally, vertically, and / or along a tapered surface.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical compensation film, characterized in that: It includes a liquid crystal compensation layer, a polymer alignment layer and a transparent electrode layer; the polymer alignment layer includes a polymer with a long side chain group or a polymer with a long side chain group and a photosensitive group, and has a thickness of 50 to 70 nm; the liquid crystal compensation layer includes a liquid crystal molecule with a double bond long side chain with terphenyl as the core, and has a thickness of 700 to 2000 nm; the transparent electrode layer has a thickness of 800 to 1000 nm; The polymer alignment layer is arranged on one side of the liquid crystal compensation layer, and the transparent electrode layer is arranged on a side of the polymer alignment layer away from the liquid crystal compensation layer.

2. The optical compensation film according to claim 1, characterized in that: The Δn of the liquid crystal molecules in the liquid crystal compensation layer is 0.1-0.3, where Δn is the difference between the refractive index of the liquid crystal molecules parallel to the optical axis and the refractive index of the liquid crystal molecules perpendicular to the optical axis.

3. The optical compensation film according to claim 1, characterized in that: The liquid crystal molecules with terphenyl as the core and long double-bond side chains include PGP-3-V and / or PGP-V-4 liquid crystal single crystals.

4. The optical compensation film according to any one of claims 1 to 3, characterized in that: The liquid crystal compensation layer includes a chiral liquid crystal dopant.

5. The optical compensation film according to claim 1, characterized in that: The polymer alignment layer includes a polyimide polymer.

6. The optical compensation film according to claim 1, characterized in that: It also includes a first base film layer, a second base film layer and a bonding layer; the first base film layer is arranged on a side of the transparent electrode layer away from the liquid crystal compensation layer, the bonding layer is arranged on the other side of the liquid crystal compensation layer opposite to the polymer alignment layer, and the second base film layer is arranged on a side of the bonding layer away from the liquid crystal compensation layer; The thickness of the bonding layer is 700-1000 nm, and the thickness of the first base film layer and the second base film layer is ≤5000 nm.

7. A method for preparing an optical compensation film according to any one of claims 1 to 5, characterized in that: include: The target material is sputtered to form a transparent electrode layer; Applying a polymer material on the surface of the transparent electrode layer, and forming a polymer alignment layer after drying and curing; The liquid crystal material is coated on the surface of the polymer alignment layer, and after drying and curing, a liquid crystal compensation layer is formed.

8. The preparation method according to claim 7, characterized in that: include: Curing the transparent slurry to form a first base film layer; Performing target sputtering on the surface of the first base film layer to form a transparent electrode layer; Applying a polymer material on the surface of the transparent electrode layer, and forming a polymer alignment layer after drying and curing; Applying liquid crystal material on the surface of the polymer alignment layer, and forming a liquid crystal compensation layer after drying and curing; An adhesive is coated on the surface of the liquid crystal compensation layer to form a bonding layer, and then a transparent slurry is cured on the surface of the bonding layer to form a second base film layer.

9. A polarizer, characterized in that: It comprises a first polarizing layer protective layer, a polarizing layer, a second polarizing layer protective layer, an adhesive layer, and the optical compensation film according to any one of claims 1 to 6; The polarizer is disposed on one side of the first polarizing layer protective layer, and the polarizing layer, the second polarizing layer protective layer, the bonding layer and the optical compensation film are stacked in sequence in a direction gradually away from the first polarizing layer protective layer.

10. A display device, characterized in that: It comprises a display panel, a backlight module and the polarizer as claimed in claim 9; the polarizers are respectively arranged on both sides of the glass substrate of the display panel, the polarizer on the light-emitting side is an upper polarizer, and the polarizer on the light-emitting side is a lower polarizer; the backlight module is arranged on the side of the lower polarizer away from the display panel.

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