Optical film group and display device

Abstract

The invention discloses an optical film group and a display device, and belongs to the technical field of display. The optical film group comprises a light collecting layer, a cholesteric liquid crystal layer, a phase difference layer, a linear polarization layer and a visual angle compensation layer, the display device comprises a display substrate and the optical film group. The light collecting layer is located between the display substrate and the cholesteric liquid crystal layer, the phase difference layer is located on the side, away from the display substrate, of the cholesteric liquid crystal layer, the linear polarization layer is located on the side, away from the cholesteric liquid crystal layer, of the phase difference layer, and the visual angle compensation layer is located on the side, away from the display substrate, of the cholesteric liquid crystal layer. The light collecting layer is used for collecting large-angle light emitted by the display substrate into small-view-angle collimated light to be emitted to the cholesteric liquid crystal layer, and the problems of regulation and control light wavelength blue shift caused by a large incidence angle of the cholesteric liquid crystal layer and too fast brightening efficiency attenuation under a large view angle are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of display and relates to an optical film group and a display device. BACKGROUND

[0002] In OLED display, a circular polarizer is used to shield ambient light and improve display effect. However, the circular polarizer will also cause more than 50% of the light emitted by the display substrate to be absorbed by the linear polarizer, thereby reducing the light emission efficiency. In LCD display, the lower polarizer will also cause more than 50% of the light to be lost.

[0003] To improve the light emission efficiency, a cholesteric liquid crystal layer is introduced in OLED display, and through the circular polarization dichroism thereof, the left-handed (right-handed) circularly polarized light is transmitted according to the helical structure, and the right-handed (left-handed) circularly polarized light is reflected. The reflected light is converted into the left-handed (right-handed) circularly polarized light that can pass through the cholesteric liquid crystal layer through the reflection electrode or reflection layer in the display device, thereby improving the light emission efficiency. In LCD, a phase difference film is needed between the cholesteric liquid crystal layer and the linear polarizer for the conversion between the circularly polarized light (elliptically polarized light) and the linearly polarized light. However, under large viewing angles, the helical structure of the cholesteric liquid crystal is sensitive to the incident angle, which causes the wavelength of the regulated light to be blue-shifted, thereby causing the display device to have color deviation and reduced color gamut under large viewing angles. Therefore, there is an urgent need for an optical film group for correcting the color deviation and reduced color gamut of the display device caused by the cholesteric liquid crystal layer under large viewing angles. SUMMARY

[0004] In view of the above technical problems and defects, the application provides an optical film group and a display device. The application adds a light collecting layer between the cholesteric liquid crystal layer and the display substrate, collects the large-angle light emitted by the display substrate into small-angle collimated light, and causes the collimated light to be incident on the cholesteric liquid crystal layer, thereby reducing the problems of wavelength blue shift of the regulated light caused by the cholesteric liquid crystal layer due to large incident angles and rapid decay of the brightening efficiency under large viewing angles.

[0005] In a first aspect, the application provides an optical film group, which is arranged on a display substrate. The circular polarizer includes a light collecting layer, a cholesteric liquid crystal layer, a phase difference layer, a linear polarizer, and a viewing angle compensation layer. The cholesteric liquid crystal layer is located between the display substrate and the phase difference layer, the linear polarizer is located on the side of the phase difference layer away from the cholesteric liquid crystal layer, the light collecting layer is located between the cholesteric liquid crystal layer and the display substrate, and the viewing angle compensation layer is located on the side of the cholesteric liquid crystal layer away from the display substrate.

[0006] Further, in the optical film group provided by the application, the light collecting layer is made of closely arranged conical microstructures. The conical microstructure has an apex angle of 20-80° and a thickness of 0.5-5 μm.

[0007] Further, the optical film set provided by the present application, the material of the light collecting layer is polyurethane acrylic resin.

[0008] Further, the optical film set provided by the present application, the view angle compensation layer is located between the cholesteric liquid crystal layer and the phase difference layer, or between the phase difference layer and the linear polarizing layer, or on the side of the linear polarizing layer away from the phase difference layer.

[0009] Further, the optical film set provided by the present application, the view angle compensation layer is located on the side of the linear polarizing layer away from the phase difference layer.

[0010] Further, the optical film set provided by the present application, the light collecting layer and the cholesteric liquid crystal layer are bonded by an optical adhesive layer.

[0011] Further, the optical film set provided by the present application, the thickness of the optical adhesive layer is 1-100 μm.

[0012] In the second aspect, the present application provides a display device, which is composed of the above optical film set and a display substrate.

[0013] Further, the display device provided by the present application, the display substrate is an organic light emitting diode or a liquid crystal display.

[0014] Compared with the prior art, the technical scheme provided by the present application has at least the following advantages: The present application adds a light collecting layer between the cholesteric liquid crystal layer and the display substrate, the light collecting layer converts the large-angle light (30°-80°) emitted by the display substrate into light with an angle of less than 30°, which is incident to the cholesteric liquid crystal layer, reduces the problem of wavelength blue shift of the cholesteric liquid crystal layer for regulating light with large viewing angle, improves the brightness enhancement efficiency of the cholesteric liquid crystal layer, and improves the color gamut of the display device.

[0015] The present application adds a view angle compensation layer on the side of the cholesteric liquid crystal layer away from the display substrate, which compensates for the problem of small viewing angle and rapid brightness decay at large viewing angle caused by the light collecting layer and the cholesteric liquid crystal layer. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The figure is a schematic diagram of the brightness enhancement principle of the cholesteric liquid crystal layer. L is left circularly polarized light, R is right circularly polarized light, S00 is a display substrate, and S01 is a cholesteric liquid crystal layer.

[0017] Figure 2 The figure is a schematic diagram of the light path of the optical film set for correcting color cast and color gamut of the display device at large viewing angle. L is left circularly polarized light, R is right circularly polarized light, S00 is a display substrate, S01 is a cholesteric liquid crystal layer, S02 is a light collecting layer, and S03 is a view angle compensation layer. DETAILED DESCRIPTION

[0018] The technical solutions of the present application are described below in conjunction with examples, but the present application is not limited to the following examples. The experimental methods and detection methods described in each example are all conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0019] The present application provides an optical film group, which comprises a light collecting layer, a cholesteric liquid crystal layer, a phase difference layer, a linear polarizing layer and a viewing angle compensation layer. The preparation method and control principle of the cholesteric liquid crystal layer, the phase difference layer and the linear polarizing layer are the same as those of patents CN120195795A, CN119882119A and CN119916602A, and the preparation method and control principle of the viewing angle compensation layer are the same as those of patent CN119916602A; the light collecting layer is prepared by closely arranging conical microstructures, the apex angle of the microstructures is 20°-80°, the thickness is 0.5-5 μm, and the material is polyurethane acrylic resin; the light collecting layer and the cholesteric liquid crystal layer are bonded by an optical adhesive layer, and the thickness of the optical adhesive layer is 1-100 μm.

[0020] The present application also provides a display device, which comprises a display substrate and the above-mentioned optical film group, and the display substrate is an organic light-emitting diode (OLED) or a liquid crystal display (LCD).

[0021] For the cholesteric liquid crystal layer, the relationship between the wavelength of the light controlled and the pitch is as follows:

[0022] In the above formula, λ is the wavelength of the light controlled by the cholesteric liquid crystal layer, n is the average refractive index of the cholesteric liquid crystal layer, P is the pitch of the cholesteric liquid crystal layer, and θ is the included angle between the incident light and the helical axis of the cholesteric liquid crystal layer.

[0023] As shown in Figure 1 At an incident angle of 0, the light path of the cholesteric liquid crystal layer is as follows: the cholesteric liquid crystal layer converts the light emitted by the display substrate into part of left-handed polarized light and part of right-handed polarized light, when the optical rotation selectivity of the cholesteric liquid crystal layer allows the left-handed (right-handed) circularly polarized light to pass through, this part is recorded as L (R), then the right-handed (left-handed) circularly polarized light (recorded as R (L)) is reflected back to the reflecting layer of the display substrate, after being reflected by the reflecting layer again, the polarization direction of the light changes, i.e. the left-handed (right-handed) circularly polarized light becomes right-handed (left-handed) circularly polarized light, the circularly polarized light with the changed polarization direction can pass through the cholesteric liquid crystal layer, and after passing through the phase difference layer, it is converted into linearly polarized light, and the linearly polarized light reaches the surface of the display device after passing through the linear polarizing layer.

[0024] The 0° of the incident angle and the viewing angle in the present application refers to the angle perpendicular to the display panel, and the angle parallel to the display panel is 90°. The incident angle and the viewing angle in the present application are 30° (including the left angle and the right angle), and no specific distinction is made, and the following is not repeated.

[0025] When the incident angle is not 0, under the above light path, the light emitted by the display panel passes through the cholesteric liquid crystal layer, and the following problems exist: during the reflection of the L part back to the display substrate reflection layer by the cholesteric liquid crystal layer, part of the light is reflected to the edge of the display device, causing part of the light loss; or the L part is reflected back to the display substrate reflection layer by the cholesteric liquid crystal layer, and after being reflected by the reflection layer, part of the light is reflected to the edge of the display device, causing part of the light loss. The larger the viewing angle, the lower the brightness enhancement efficiency of the cholesteric liquid crystal layer, which further leads to poor display effect under a large viewing angle, and as the incident angle increases, the cholesteric liquid crystal layer controls the wavelength of the light to move to the short wavelength direction, causing color deviation of the display device under a large viewing angle, which affects the display effect.

[0026] At the same time, under a certain incident angle, because the refractive index of the cholesteric liquid crystal layer in the plane and the thickness direction is usually inconsistent, a certain phase difference will be caused, which further causes the light under a certain incident angle to be elliptical polarized light instead of circular polarized light after passing through the cholesteric liquid crystal layer. Taking the cholesteric liquid crystal layer prepared by adding a chiral compound to a nematic liquid crystal as an example, the long axis of the nematic liquid crystal molecule is perpendicular to the thickness direction, and the R th value of the cholesteric liquid crystal layer is

[0027] In the above formula, R th is the phase difference value in the thickness direction of the cholesteric liquid crystal layer, n o is the refractive index in the surface optical axis direction of the liquid crystal polymer layer, n e is the refractive index in the surface perpendicular optical axis direction of the cholesteric liquid crystal layer, n z is the refractive index in the thickness direction of the cholesteric liquid crystal layer, and d is the thickness of the cholesteric liquid crystal layer.

[0028] Based on this, the present application introduces a light collecting layer between the display substrate and the cholesteric liquid crystal layer to solve the above problems. For example Figure 2As shown, the light-collecting layer is used to collect the large-angle light (30~80°) emitted from the display substrate into collimated light with a small viewing angle (small <30°) which is then incident on the cholesteric liquid crystal layer. Part of the light (denoted as R(L)) can pass through the cholesteric liquid crystal layer and be converted into right-handed (left-handed) circularly polarized light or elliptically polarized light. R can pass through the phase difference layer and the linear polarization layer. The other part of the light (L) is reflected back to the display substrate by the cholesteric liquid crystal layer. Its polarization state is left-handed (right-handed) circularly polarized light or elliptically polarized light. After being reflected again by the display substrate, its polarization state is opposite to that of L and the same as that of R. It can pass through the cholesteric liquid crystal layer, the phase difference layer, the linear polarization layer and the viewing angle compensation layer. Through the above optical path, the cholesteric liquid crystal layer improves the light emission efficiency of the display device.

[0029] For example, the light emitted from the display substrate passes through the light-collecting layer and then enters the cholesteric liquid crystal layer at a small angle, such as within 10°. The portion of the light that passes through is left-handed (right-handed) circularly polarized light or elliptically polarized light. After passing through the light-diffusing layer, it is transformed into emitted light with more uniform viewing angles. The portion of right-handed (left-handed) circularly polarized light or elliptically polarized light reflected by the cholesteric liquid crystal layer passes through the light-collecting layer, is reflected by the display substrate, and then passes through the light-collecting layer, the cholesteric liquid crystal layer, and the viewing angle compensation layer to reach the viewing angle side.

[0030] As can be seen from the formula relating the wavelength of light modulated by the cholesteric liquid crystal layer to the incident angle, reducing the incident angle can reduce the defect of wavelength shift towards shorter wavelengths in the cholesteric liquid crystal layer, thereby reducing color shift at wide viewing angles and improving display performance. In other words, the light-collecting layer reduces the blue shift of the wavelength of light modulated by the cholesteric liquid crystal layer, improving the brightness enhancement film efficiency of the cholesteric liquid crystal layer.

[0031] Example 1 This embodiment provides a light-gathering layer.

[0032] The light-collecting layer described in this embodiment is as follows: Figure 2 As shown in S02, it is made of closely arranged conical microstructures, the apex angle of which is 60°, the thickness is 2μm, and the material is polyurethane acrylic resin.

[0033] Example 2 This embodiment provides an optical composite film layer.

[0034] The optical composite film layer described in this embodiment consists of a light-collecting layer and a cholesteric liquid crystal layer. The preparation of the cholesteric liquid crystal layer is consistent with that of Example 8 disclosed in patent CN119916602A, and the light-collecting layer is the same as in Example 1. The light-collecting layer and the cholesteric liquid crystal layer are bonded together using an optical adhesive layer. The optical adhesive is selected from W3-OCA020-6 of Hengshan Jiacheng New Materials Co., Ltd., and the thickness of the optical adhesive layer is 5 μm.

[0035] Specifically, the method for preparing the cholesteric phase liquid crystal layer in this embodiment is as follows: The cholesteric liquid crystal layer has a single pitch structure in the thickness direction, with a pitch of 291 nm, a control center wavelength of 460 nm, a control light band of 440~480 nm, and a thickness of 3 μm.

[0036] Methods for preparing cholesteric liquid crystal layers include: One side of the TAC (cellulose triacetate) membrane was subjected to corona treatment with a power of 100V*2A and a corona velocity of 2m / min. Polymerizable liquid crystal monomers, chiral compounds, photoinitiators, and solvents were measured in specific proportions to obtain a liquid crystal mixture, the mass percentages of which are shown in Table 1. The measured liquid crystal mixture was heated to 180℃ while stirring continuously until homogeneous, and then cooled to 30℃ for later use.

[0037] Table 1. Mass percentage of each component in the liquid crystal mixture

[0038] The liquid crystal mixture was coated onto a corona-treated substrate layer using a slit-coating process. The coating thickness was 3 μm. The substrate was then heated to 80°C and held for 1 minute to remove the solvent. Finally, it was cured by ultraviolet (UV) irradiation at a wavelength of 365 nm and a dose of 5000 J / m². 2 This forms a cholesteric phase liquid crystal layer.

[0039] The structures of the compounds involved in Table 1 are as follows: L1: ; L2: ; L3: ; L6: ; X13: .

[0040] Example 3 This embodiment provides an optical composite film layer.

[0041] The optical composite film layer described in this embodiment consists of a light-collecting layer and a cholesteric liquid crystal layer. The structure, preparation method, and control principle of the cholesteric liquid crystal layer are consistent with Example 9 disclosed in patent CN119916602A, and the light-collecting layer is the same as in Example 1. The light-collecting layer and the cholesteric liquid crystal layer are bonded together using an optical adhesive layer. The optical adhesive is selected from W3-OCA020-6 of Hengshan Jiacheng New Materials Co., Ltd., and the thickness of the optical adhesive layer is 10 μm.

[0042] Specifically, the method for preparing the cholesteric phase liquid crystal layer in this embodiment is as follows: The cholesteric liquid crystal layer has three different pitch structures in the thickness direction: a P1 liquid crystal polymer layer with a pitch of 291 nm and a thickness of 3 μm; a P2 liquid crystal polymer layer with a pitch of 335 nm and a thickness of 3.5 μm; and a P3 liquid crystal polymer layer with a pitch of 392 nm and a thickness of 4 μm; the total thickness of the cholesteric liquid crystal layer is 10.5 μm.

[0043] Methods for preparing cholesteric liquid crystal layers include: (1) Pretreatment of the substrate layer, (2) Preparation of the liquid crystal mixture, and (3) Coating of the liquid crystal mixture are the same as in Example 2, except that P1 liquid crystal polymer layer, P2 liquid crystal polymer layer, and P3 liquid crystal polymer layer are sequentially coated on the substrate layer after corona treatment. The liquid crystal mixture for preparing P1 liquid crystal polymer layer is the same as the liquid crystal mixture described in Example 2. The difference between the raw materials for preparing P2 liquid crystal polymer layer and P1 liquid crystal polymer layer is that the content of X13 compound (chiral compound) is 1.7%, and the content of propylene glycol monomethyl ether acetate (organic solvent) is 16.3%. The difference between the raw materials for preparing P3 liquid crystal polymer layer and P1 liquid crystal polymer layer is that the content of X13 compound (chiral compound) is 1.4%, and the content of propylene glycol monomethyl ether acetate (organic solvent) is 16.6%.

[0044] Example 4 This embodiment provides an optical film assembly.

[0045] The optical film assembly described in this embodiment consists of a light-collecting layer, a cholesteric liquid crystal layer, a retardation layer, a linear polarizing layer, and a viewing angle compensation layer. The cholesteric liquid crystal layer is located between the display substrate and the retardation layer. The linear polarizing layer is located on the side of the retardation layer away from the cholesteric liquid crystal layer. The light-collecting layer is located between the cholesteric liquid crystal layer and the display substrate. The viewing angle compensation layer is located on the side of the linear polarizing layer away from the display substrate. That is, the viewing angle compensation layer is located between the cholesteric liquid crystal layer and the retardation layer.

[0046] In this embodiment, the light-collecting layer and the cholesteric liquid crystal layer are bonded together, meaning that the light-collecting layer and the cholesteric liquid crystal layer are the optical composite film layer described in Example 2. The structure, preparation method, and control principle of the viewing angle compensation layer are consistent with the viewing angle compensation layer disclosed in patent CN119916602A. To optimize the performance of the optical film assembly of this invention, the viewing angle compensation layer preferably uses the technical solution corresponding to the optimal embodiment described in patent CN119916602A. The structure, preparation method, and control principle of the phase retardation layer and the linear polarizing layer are consistent with the phase retardation layer and the linear polarizing layer disclosed in patent CN117844494A.

[0047] Specifically, the preferred method for preparing the view compensation layer described in this embodiment is as follows: View compensation particles were obtained by mixing silica of different particle sizes. The mass percentage of silica of each particle size in the view compensation particles is shown in Table 2. Table 2. Mass percentage of each component in the perspective compensation particles

[0048] One side of the TAC (cellulose triacetate) film substrate was subjected to corona treatment with a power of 100V*2A and a corona velocity of 2m / min. Polymerizable liquid crystal monomers, chiral compounds, photoinitiators, and solvents were measured in specific proportions to obtain a liquid crystal mixture, the mass percentages of which are shown in Table 3. The measured liquid crystal mixture was heated to 180℃ while stirring until homogeneous. After cooling to 50℃, viewing angle compensation particles were mixed with the liquid crystal mixture at a mass ratio of 0.3:1 to form a coating mixture for later use.

[0049] Table 3. Mass percentage of each component in the liquid crystal mixture

[0050] The coating mixture was applied to a corona-treated substrate layer using a slot coating process. The coating thickness was 3 μm. The substrate was heated to 80°C and held for 1 minute to remove the solvent. The temperature was then lowered to 20°C, followed by UV curing at a wavelength of 365 nm and a dose of 5000 J / m². 2 This results in a view compensation layer.

[0051] The structures of the compounds involved in Table 3 are as follows: L4: ; The structure of X5 is as follows: .

[0052] Example 5 The optical film assembly described in this embodiment is the same as that in Embodiment 4, except that the light-collecting layer and the cholesteric liquid crystal layer in this embodiment are selected from Embodiment 3.

[0053] Example 6 The optical film group described in this embodiment is the same as that in embodiment 5, except that the viewing angle compensation layer of the optical film group described in this embodiment is located between the phase difference layer and the linear polarization layer.

[0054] Example 7 The optical film group described in this embodiment is the same as that in embodiment 5, except that the viewing angle compensation layer of the optical film group described in this embodiment is located on the side of the linear polarization layer away from the phase difference layer.

[0055] Comparative Example 1 The optical film assembly described in this comparative example is the same as that in Example 5, except that the optical film assembly described in this comparative example does not contain a light-collecting layer.

[0056] Examples 8-11 The display devices described in Examples 8-11 include the optical film group and display substrate described in Examples 4-7, wherein the display substrate is an organic light-emitting diode (OLED).

[0057] Comparative Example 2 Comparative Example 2 is the same as Example 9, except that the optical film assembly of Example 9 is replaced with the optical film assembly described in Comparative Example 1.

[0058] Example 12 This embodiment is the same as embodiment 9, except that the organic light-emitting diode (OLED) display substrate in embodiment 9 is replaced with a liquid crystal display (LCD) display substrate.

[0059] Comparative Example 3 This comparative example is the same as Comparative Example 2, except that the organic light-emitting diode (OLED) display substrate in Comparative Example 2 is replaced with a liquid crystal display (LCD) display substrate.

[0060] The color shifts of the display devices in Examples 8-12 and Comparative Examples 4-7 under different viewing angles are shown in Table 4, and the color gamuts are shown in Table 5. The color shift was measured using a DS-210 colorimeter, with the color shift value ΔE. The color gamut was measured using an s-RGB-M002 meter, and the measured values ​​were expressed as percentages.

[0061] Table 4 shows the color shift values ​​(ΔE) of the display device at different viewing angles.

[0062] As shown in Table 4, the color shift performance of the display devices in Examples 8-12 is significantly better than that of Comparative Examples 2-3 at different viewing angles. Specifically, the color shift value (ΔE) of the display devices in Examples 8-12 is ≤2.63 within a viewing angle range of 10° to 80°. The color shift growth curve with increasing viewing angle is gentle, indicating excellent color fidelity and superior viewing angle stability. In contrast, the color shift value of the display devices in Comparative Examples 2-3 increases sharply with increasing viewing angle, especially within the viewing angle range of 20° to 80°. The color shift value (ΔE) increases rapidly in an almost linear manner, reaching 5.60-6.30 at a 50° viewing angle and as high as 13.60-14.00 at an 80° viewing angle. The colors are severely distorted and cannot meet the requirements for viewing at large viewing angles.

[0063] Table 5 shows the color gamut (%) of the display device at different viewing angles.

[0064] As shown in Table 5, the display devices of Examples 8-12 exhibit significantly better color gamut maintenance capabilities than Comparative Examples 2-3 at different viewing angles. Specifically, the display devices of Examples 8-12 maintain a color gamut of 95.2% within a viewing angle range of 10° to 80°, with a very slow decrease in color gamut over time, resulting in excellent preservation of color range and vibrancy. In contrast, the color gamut of the display devices of Comparative Examples 2-3 decreases sharply with increasing viewing angle, with the color gamuts of Comparative Examples 2 and 3 decreasing to 85.8% and 81.5%, respectively.

[0065] The light-collecting layer provided by this invention can correct the color shift and color gamut reduction caused by the cholesteric liquid crystal layer in display devices at wide viewing angles, rather than simply focusing the emitted light.

[0066] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art through related deductions and substitutions based on the inventive concept, without inventive effort, are within the scope of protection of the present invention.

Claims

1. An optical film set disposed on a display substrate, characterized by, The circular polarizer comprises a light collecting layer, a cholesteric liquid crystal layer, a phase difference layer, a linear polarizing layer and a viewing angle compensation layer. The cholesteric liquid crystal layer is located between the display substrate and the phase difference layer, the linear polarizing layer is located on the side of the phase difference layer away from the cholesteric liquid crystal layer, the light collecting layer is located between the cholesteric liquid crystal layer and the display substrate, and the viewing angle compensation layer is located on the side of the cholesteric liquid crystal layer away from the display substrate.

2. The optical film set of claim 1, wherein, The light collecting layer is prepared by closely arranging conical microstructures. The conical microstructures have an apex angle of 20-80° and a thickness of 0.5-5 μm.

3. The optical film set of claim 1, wherein, The light collecting layer is made of polyurethane acrylic resin.

4. The optical film set of claim 1, wherein, The viewing angle compensation layer is located between the cholesteric liquid crystal layer and the phase difference layer, or between the phase difference layer and the linear polarizing layer, or on the side of the linear polarizing layer away from the phase difference layer.

5. The optical film set of claim 4, wherein, The viewing angle compensation layer is located on the side of the linear polarizing layer away from the phase difference layer.

6. The optical film set of claim 1, wherein, The light collecting layer and the cholesteric liquid crystal layer are bonded by an optical adhesive layer.

7. A display device, characterized by comprising: The display device is composed of the optical film set according to any one of claims 1-6 and a display substrate.

8. The display device according to claim 7, wherein The display substrate is an organic light emitting diode or a liquid crystal display.

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