Optical film, optical film material and display device

Abstract

The invention discloses an optical film, an optical film material and a display device, the optical film comprises a base material layer and a depolarization function layer arranged on one side of the base material layer, the depolarization function layer comprises N liquid crystal film layers, the N liquid crystal film layers are stacked in the thickness direction of the optical film, and N is larger than or equal to 2; wherein the alignment directions of any two liquid crystal film layers are different, and the optical film is configured to convert linearly polarized light incident to the optical film into elliptically polarized light and / or circularly polarized light with randomly distributed light vectors; the optical film can convert linearly polarized light into elliptically polarized light or circularly polarized light similar to natural light so as to achieve the effect of eye protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an optical film, an optical film material and a display device. BACKGROUND

[0002] For a liquid crystal display (LCD), natural light first passes through a lower polarizer to form linearly polarized light, then passes through a liquid crystal film layer to convert the linearly polarized light into elliptically polarized light by the birefringence of liquid crystal molecules, then passes through an upper polarizer with a polarization axis perpendicular to the polarization axis of the lower polarizer to convert the elliptically polarized light into linearly polarized light again, and finally exits in the form of linearly polarized light. However, the linearly polarized light exiting the LCD can cause great damage to the macular area of the retina of the viewer's fundus. SUMMARY

[0003] The present application provides an optical film, an optical film material and a display device, which can convert linearly polarized light into elliptically polarized light or circularly polarized light similar to natural light to achieve the effect of eye protection.

[0004] The present application provides an optical film, which comprises:

[0005] a substrate layer;

[0006] a depolarization functional layer disposed on one side of the substrate layer, the depolarization functional layer comprising N layers of liquid crystal film layers, the N layers of liquid crystal film layers being stacked along the thickness direction of the optical film, and N≥2;

[0007] wherein the alignment directions of any two layers of the liquid crystal film layers are different, and the optical film is configured to convert linearly polarized light incident on the optical film into elliptically polarized light and / or circularly polarized light with random distribution of light vectors.

[0008] In some embodiments, the depolarization functional layer further comprises N layers of alignment layers, the N layers of alignment layers being disposed one-to-one corresponding to the N layers of liquid crystal film layers.

[0009] wherein the Nth alignment layer is disposed on one side of the Nth liquid crystal film layer, and the Nth alignment layer is configured to align the liquid crystal molecules in the Nth liquid crystal film layer; the alignment directions of any two layers of the alignment layers are different.

[0010] In some embodiments, the depolarization functional layer comprises:

[0011] a first alignment layer disposed on one side of the substrate layer;

[0012] a first liquid crystal film layer disposed on one side of the first alignment layer away from the substrate layer;

[0013] a second alignment layer disposed on a side of the first liquid crystal film layer distal from the first alignment layer;

[0014] a second liquid crystal film layer disposed on a side of the second alignment layer distal from the first liquid crystal film layer;

[0015] wherein the alignment direction of the first alignment layer is different from the alignment direction of the second alignment layer.

[0016] In some embodiments, the depolarization functional layer further comprises:

[0017] a third alignment layer disposed on a side of the second liquid crystal film layer distal from the second alignment layer;

[0018] a third liquid crystal film layer disposed on a side of the third alignment layer distal from the second liquid crystal film layer;

[0019] wherein the alignment direction of the third alignment layer is different from the alignment direction of the first alignment layer and the alignment direction of the second alignment layer.

[0020] The present application provides an optical film material for forming the optical film as described above;

[0021] The optical film material comprises a liquid crystal composition for forming the liquid crystal film layer, wherein the liquid crystal composition comprises one or more compounds represented by Formula I, one or more compounds represented by Formula II, one or more compounds represented by Formula III, and one or more compounds represented by Formula IV:

[0022]

[0023] wherein R1, R2, R3, R4, R5, and R6 are selected from -H, -F, -Cl, -Br, -CN, -SCN, -NCS, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkynyl having 2-10 carbon atoms, or alkynyloxy having 2-10 carbon atoms, the terminal groups of R1, R2, R3, R4, R5, and R6 are unsubstituted or substituted with -CN or -CF3, one or more non-adjacent -CH2- in R1, R2, R3, R4, R5, and R6 are unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C- and the heteroatom is not directly bonded, one or more H in R1, R2, R3, R4, R5, and R6 are unsubstituted or substituted with F, Cl, Br, I;

[0024] Z1, Z2and Z3are selected from a single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, an alkylene group having 1-10 carbon atoms, an alkenylene group having 2-10 carbon atoms or an alkynyl group having 2-10 carbon atoms, one or more non-adjacent -CH2- in Z1, Z2and Z3are not substituted or substituted with any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- or -C≡C-, one or more H in Z1, Z2and Z3are not substituted or substituted with F, Cl, Br or I;

[0025] selected from wherein one or more non-adjacent -CH2- are not substituted or substituted with -O-, one or more H are not substituted or substituted with F, Cl, Br or I;

[0026] the H on the phenyl ring of the compound of formula IV are not substituted or substituted with F, Cl, Br, CN, SCN, NCS, an alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkenyloxy group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms or an alkynyloxy group having 2-10 carbon atoms;

[0027] L is selected from H, F, Cl, CF3, Sp, an alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkenyloxy group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms, an alkynyloxy group having 2-10 carbon atoms, a cycloalkane having 3-10 carbon atoms or an aromatic ring having 3-10 carbon atoms, one or more non-adjacent -CH2- in L are not substituted or substituted with any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CH2CH2-, -(CH2)3-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, one or more H in L are not substituted or substituted with F, Cl, Br or I;

[0028] a and b are selected from 0, 1 or 2, and a+b > 1;

[0029] c and m are selected from 0, 1 or 2;

[0030] Sp is selected from a branched or unbranched ether, alkyl, alkoxy, alkenyl, alkenyloxy or polymerizable group;

[0031] In the compound of Formula IV, at least one Sp is selected from Formula V or Formula VI:

[0032]

[0033] wherein n is selected from any integer from 0 to 10;

[0034] Z4 is selected from a single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, an alkylene having 1 to 10 carbon atoms, an alkenylene having 2 to 10 carbon atoms or an alkynyl having 2 to 10 carbon atoms, one or more non-adjacent -CH2- in Z4 are unsubstituted or substituted with any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- and -C≡C-, one or more H in Z4 are unsubstituted or substituted with F, Cl, Br, I.

[0035] In some embodiments, Formula I is selected from any one of Formula I-1 to Formula I-12:

[0036]

[0037] Formula II is selected from any one of Formula II-1 to Formula II-3:

[0038]

[0039]

[0040] Formula III is selected from any one of Formula III-1 to Formula III-3:

[0041]

[0042] Formula IV is selected from any one of Formula IV-1 to Formula IV-18:

[0043]

[0044]

[0045] In some embodiments, the liquid crystal composition comprises liquid crystal compounds and polymer monomers, wherein the liquid crystal compounds comprise compounds represented by Formula I, Formula II and Formula III, and the polymer monomers comprise compounds represented by Formula IV.

[0046] In the liquid crystal composition, the mass percentage of the liquid crystal compounds ranges from 0.1% to 20%, and the mass percentage of the polymer monomers ranges from 5% to 30%.

[0047] In the liquid crystal compounds, the mass percentage of the compound represented by Formula I ranges from 1% to 70%, the mass percentage of the compound represented by Formula II ranges from 1% to 50%, and the mass percentage of the compound represented by Formula III ranges from 1% to 50%.

[0048] In some embodiments, the optical film material further comprises an alignment agent for forming the alignment layer, and the alignment agent comprises a diamine compound and an acid anhydride compound.

[0049] In the diamine compound, the compound is selected from at least one of Formula VII-1 to Formula VII-4:

[0050]

[0051] In the acid anhydride compound, the compound is selected from at least one of Formula VIII-1 to Formula VIII-2:

[0052]

[0053] In the acid anhydride compound, the compound is selected from at least one of Formula VIII-1 to Formula VIII-2:

[0054] In some embodiments, in the alignment agent, the mass percentage of the diamine compound ranges from 0.1% to 10%, and the mass percentage of the acid anhydride compound ranges from 0.1% to 10%.

[0055] The present application also provides a display device, comprising:

[0056] a display panel;

[0057] a first polarizer disposed on the light exit side of the display panel; and

[0058] an optical film as described above disposed on the side of the first polarizer away from the display panel.

[0059] In some embodiments, the angle between the alignment direction of the first liquid crystal film layer and the light transmission axis of the first polarizer is θ1, and the angle between the alignment direction of the N-1th liquid crystal film layer and the light transmission axis of the first polarizer is θN-1. N-1an angle between an alignment direction of the Nth liquid crystal film layer and a transmission axis of the first polarizer is θ N , θ1≠…≠θ N-1 ≠θ N , 0° < θ1 < 90°, 0° < θ N-1 < 90°, 0° < θ N < 90°.

[0060] In some embodiments, an angle between an alignment direction of the first alignment layer and a transmission axis of the first polarizer is θ1, an angle between an alignment direction of the N-1th alignment layer and the transmission axis of the first polarizer is θ N-1 , an angle between an alignment direction of the Nth alignment layer and the transmission axis of the first polarizer is θ N , θ1≠…≠θ N-1 ≠θ N , 0° < θ1 < 90°, 0° < θ N-1 < 90°, 0° < θ N < 90°.

[0061] In some embodiments, |θ N -θ N-1 |≥5°.

[0062] The present application provides an optical film, an optical film material and a display device, the optical film of the present application comprises a depolarization functional layer, the depolarization functional layer comprises N layers of liquid crystal film layers stacked in the thickness direction of the optical film, wherein N≥2, and each liquid crystal film layer has an independent alignment direction, and the alignment directions of any two liquid crystal film layers are different. Since the depolarization functional layer comprises multiple liquid crystal film layers, and the alignment directions of the multiple liquid crystal film layers are different, when linearly polarized light passes through the multiple liquid crystal film layers in turn, it will undergo "multi-layer polarization state modulation", so that the linearly polarized light is finally converted into elliptically polarized light or circularly polarized light with random distribution of light vectors, realizing the depolarization effect. When the above optical film is applied to a display device, the linearly polarized light emitted by the upper polarizer can be converted into elliptically polarized light or circularly polarized light similar to natural light, avoiding damage to the viewer's ocular fundus retina, and having the effect of eye protection. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0064] Figure 1 is a structural schematic diagram of an optical film provided by the embodiments of the present application;

[0065] Figure 2 is a structural schematic diagram of another optical film provided by an embodiment of the present application;

[0066] Figure 3 is a cross-sectional structural schematic diagram of an optical film provided by an embodiment of the present application, which includes two liquid crystal film layers;

[0067] Figure 4 is a structural schematic diagram of an optical film provided by an embodiment of the present application; Figure 3 is a structural schematic diagram of an optical film provided by an embodiment of the present application;

[0068] Figure 5 is a cross-sectional structural schematic diagram of an optical film provided by an embodiment of the present application, which includes three liquid crystal film layers;

[0069] Figure 6 is a structural schematic diagram of an optical film provided by an embodiment of the present application; Figure 5 is a structural schematic diagram of an optical film provided by an embodiment of the present application;

[0070] Figure 7 is a structural schematic diagram of a display device provided by an embodiment of the present application;

[0071] Figure 8 is an optical performance test schematic diagram of an optical film provided by an embodiment of the present application.

[0072] Legend of reference signs:

[0073] 10, display device; 100, optical film; 110, substrate layer; 120, depolarization functional layer; 121, liquid crystal film layer; 1211, first liquid crystal film layer; 1212, second liquid crystal film layer; 1213, third liquid crystal film layer; 122, alignment layer; 1221, first alignment layer; 1222, second alignment layer; 1223, third alignment layer; 200, display panel; 210, array substrate; 220, counter substrate; 230, liquid crystal layer; 300, first polarizer; 400, second polarizer; 500, backlight source; 600, detector. DETAILED DESCRIPTION

[0074] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0075] An optical film 100 provided by the present application is shown in Figure 1 , Figure 1is a structural schematic diagram of an optical film 100 provided by the present application. The optical film 100 of the present application comprises a substrate layer 110 and a depolarization functional layer 120. The depolarization functional layer 120 is arranged on one side of the substrate layer 110, and the depolarization functional layer 120 comprises N layers of liquid crystal film layers 121, the N layers of liquid crystal film layers 121 are arranged in a stacked manner along the thickness direction Z of the optical film 100, and N≥2; wherein the alignment direction of any two layers of liquid crystal film layers 121 is different, and the optical film 100 is configured to convert linearly polarized light incident on the optical film 100 into elliptically polarized light and / or circularly polarized light with random distribution of light vectors.

[0076] Specifically, please refer to Figure 1 , the depolarization functional layer 120 can comprise a first liquid crystal film layer, …, an (N-1)th liquid crystal film layer, and an Nth liquid crystal film layer, which are arranged in a stacked manner along the thickness direction Z of the optical film 100 in sequence; wherein N≥2, for example, N can be 2, 3, 4, or 5, but is not limited thereto.

[0077] In the present embodiment, the first liquid crystal film layer, …, the (N-1)th liquid crystal film layer, and the Nth liquid crystal film layer each have an independent alignment direction. The above-mentioned “independent alignment direction” means that the liquid crystal molecules in each layer of liquid crystal film layers 121 are in a “single alignment” mode, i.e., the liquid crystal molecules in each layer of liquid crystal film layers 121 are arranged in the same direction, i.e., the long axes of the liquid crystal molecules have a uniform arrangement direction. Meanwhile, the alignment direction of the first liquid crystal film layer, …, the alignment direction of the (N-1)th liquid crystal film layer, and the alignment direction of the Nth liquid crystal film layer are all different. The above-mentioned “alignment direction of the liquid crystal film layer” refers to the uniform arrangement direction of the long axes of the liquid crystal molecules.

[0078] In the present application, the optical film 100 is composed of the substrate layer 110 and the depolarization functional layer 120, wherein the depolarization functional layer 120 is composed of a plurality of stacked liquid crystal film layers 121, and the alignment directions of the plurality of liquid crystal film layers 121 constituting the depolarization functional layer 120 are all different. When linearly polarized light passes through the plurality of liquid crystal film layers 121 of the depolarization functional layer 120, it is equivalent to performing “multi-level polarization state modulation” on the linearly polarized light. Due to the scattering and phase delay effects of the liquid crystal molecules in each liquid crystal film layer 121, the polarization of the linearly polarized light changes when it passes through each liquid crystal film layer 121. After passing through the plurality of liquid crystal film layers 121 with different alignment directions, the polarization direction and phase of the finally output light are randomly distributed, forming elliptically polarized light or circularly polarized light with random distribution of light vectors, which is similar to natural light, thereby realizing the depolarization effect.

[0079] It should be noted that the alignment direction of the liquid crystal film layer 121 can be realized by rubbing alignment, photo-alignment, printing alignment, electric field-induced alignment, etc. The specific alignment method can refer to the prior art, and the present application does not make any limitation.

[0080] In some embodiments, referring to Figure 2 The depolarization functional layer 120 further comprises N layers of alignment layers 122, each of which is arranged corresponding to one of the N layers of liquid crystal film layers 121; wherein the Nth alignment layer is arranged on one side of the Nth liquid crystal film layer (for example, the side of the Nth liquid crystal film layer close to the substrate layer 110 or the side of the Nth liquid crystal film layer away from the substrate layer 110), and is configured to align the liquid crystal molecules in the Nth liquid crystal film layer; the alignment directions of any two layers of alignment layers 122 are different.

[0081] Specifically, referring to Figure 2 The depolarization functional layer 120 can comprise a first alignment layer, …, an N-1th alignment layer, and an Nth alignment layer, the first alignment layer is arranged on the side of the first liquid crystal film layer close to the substrate layer 110, …, the N-1th alignment layer is arranged on the side of the N-1th liquid crystal film layer close to the N-2th liquid crystal film layer, and the Nth alignment layer is arranged on the side of the Nth liquid crystal film layer close to the N-1th liquid crystal film layer. Each alignment layer 122 has an independent alignment direction. In this embodiment, the alignment layer 122 and the corresponding liquid crystal film layer 121 are arranged adjacently to realize the alignment of the liquid crystal molecules in the liquid crystal film layer 121, so that the long axes of the liquid crystal molecules in the liquid crystal film layer 121 have a uniform arrangement direction. Each layer of liquid crystal film layer 121 has a corresponding layer of alignment layer 122 to realize that each liquid crystal film layer 121 in the depolarization functional layer 120 has an independent alignment direction. At the same time, the alignment direction of the first alignment layer, …, the alignment direction of the N-1th alignment layer, and the alignment direction of the Nth alignment layer are all different, so as to realize that the alignment directions of the liquid crystal film layers 121 in the depolarization functional layer 120 are all different.

[0082] In this embodiment, the alignment layer 122 is used to realize the alignment of the liquid crystal molecules in the liquid crystal film layer 121. This alignment method is mature in process, low in cost, and suitable for mass production. The interaction force between the alignment layer 122 and the liquid crystal molecules is stable, so that the alignment effect is stable, which is conducive to improving the service life of the optical film 100. This method is especially suitable for liquid crystal film layers 121 with single alignment, and can simplify the stacking and matching design of the alignment direction of the liquid crystal film layers 121 with multiple layers and different alignment directions, so as to simplify the process.

[0083] In some embodiments, the depolarization functional layer 120 can comprise two or three layers of liquid crystal film layers 121, that is, N is 2 or 3. Although the more layers of liquid crystal film layers 121 in the depolarization functional layer 120, the better the depolarization effect, the more layers of liquid crystal film layers 121, the lower the overall transmittance of the optical film 100, and the more layers, the higher the cost. Therefore, it is preferred that N is 2 or 3, so as to ensure that the optical film 100 has high transmittance and good depolarization effect at the same time.

[0084] Further, the depolarization functional layer 120 can further include two or three alignment layers 122, which are arranged one by one with the liquid crystal film layers 121.

[0085] In an embodiment, referring to Figure 3 and Figure 4 the depolarization functional layer 120 includes a first alignment layer 1221, a first liquid crystal film layer 1211, a second alignment layer 1222, and a second liquid crystal film layer 1212. The first alignment layer 1221 is arranged on one side of the substrate layer 110; the first liquid crystal film layer 1211 is arranged on the side of the first alignment layer 1221 away from the substrate layer 110; the second alignment layer 1222 is arranged on the side of the first liquid crystal film layer 1211 away from the first alignment layer 1221; the second liquid crystal film layer 1212 is arranged on the side of the second alignment layer 1222 away from the first liquid crystal film layer 1211; and the alignment direction of the first alignment layer 1221 is different from the alignment direction of the second alignment layer 1222.

[0086] In another embodiment, referring to Figure 5 and Figure 6 the depolarization functional layer 120 includes a first alignment layer 1221, a first liquid crystal film layer 1211, a second alignment layer 1222, a second liquid crystal film layer 1212, a third alignment layer 1223, and a third liquid crystal film layer 1213. The first alignment layer 1221 is arranged on one side of the substrate layer 110; the first liquid crystal film layer 1211 is arranged on the side of the first alignment layer 1221 away from the substrate layer 110; the second alignment layer 1222 is arranged on the side of the first liquid crystal film layer 1211 away from the first alignment layer 1221; the second liquid crystal film layer 1212 is arranged on the side of the second alignment layer 1222 away from the first liquid crystal film layer 1211; the third alignment layer 1223 is arranged on the side of the second liquid crystal film layer 1212 away from the second alignment layer 1222; the third liquid crystal film layer 1213 is arranged on the side of the third alignment layer 1223 away from the second liquid crystal film layer 1212; and the alignment direction of the first alignment layer 1221, the alignment direction of the second alignment layer 1222, and the alignment direction of the third alignment layer 1223 are all different.

[0087] The application further provides an optical film material for forming the optical film 100 as described above, which includes a substrate for forming the substrate layer and a liquid crystal composition for forming the liquid crystal film layer.

[0088] Further, the optical film material further includes an alignment agent for forming the alignment layer.

[0089] In some embodiments, the substrate is selected from one or more of poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate) (PET), polycarbonate (PC), triacetyl cellulose (TAC), cyclic olefin polymer (COP), cyclic olefin copolymer (COC), and glass. Further, the substrate can be a transparent material with high light transmittance to reduce the impact on light transmittance.

[0090] In some embodiments, the liquid crystal composition includes one or more compounds represented by Formula I, one or more compounds represented by Formula II, one or more compounds represented by Formula III, and one or more compounds represented by Formula IV, wherein the structures of Formula I, Formula II, Formula III, and Formula IV are:

[0091]

[0092] wherein R1, R2, R3, R4, R5, and R6are selected from -H, -F, -Cl, -Br, -CN, -SCN, -NCS, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkynyl having 2-10 carbon atoms, or alkynyloxy having 2-10 carbon atoms, the terminal groups of R1, R2, R3, R4, R5, and R6are unsubstituted or substituted with -CN or -CF3, one or more -CH2- in R1, R2, R3, R4, R5, and R6is unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C- and the heteroatom is not directly bonded, one or more H in R1, R2, R3, R4, R5, and R6is unsubstituted or substituted with F, Cl, Br, I;

[0093] Z1, Z2and Z3are selected from a single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, an alkylene group having 1-10 carbon atoms, an alkenylene group having 2-10 carbon atoms or an alkynyl group having 2-10 carbon atoms, one or more non-adjacent -CH2- in Z1, Z2and Z3are not substituted or substituted by any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- or -C≡C-, one or more H in Z1, Z2and Z3are not substituted or substituted by F, Cl, Br or I;

[0094] selected from wherein one or more non-adjacent -CH2- are not substituted or substituted by -O-, one or more H are not substituted or substituted by F, Cl, Br or I;

[0095] L is selected from H, F, Cl, CF3, Sp, an alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkenyloxy group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms, an alkynyloxy group having 2-10 carbon atoms, a cycloalkane having 3-10 carbon atoms or an aromatic ring having 3-10 carbon atoms, one or more non-adjacent -CH2- in L are not substituted or substituted by any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CH2CH2-, -(CH2)3-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, one or more H in L are not substituted or substituted by F, Cl, Br or I;

[0096] H on the phenyl ring of the compound represented by formula IV is not substituted or substituted by F, Cl, Br, CN, SCN, NCS, an alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkenyloxy group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms or an alkynyloxy group having 2-10 carbon atoms;

[0097] a and b are selected from 0, 1 or 2, and a+b > 1;

[0098] c and m are selected from 0, 1 or 2;

[0099] Sp is selected from a branched or unbranched ether, alkyl, alkoxy, alkenyl, alkenyloxy or polymerizable group, and at least one Sp in the compound of Formula IV is selected from a polymerizable group.

[0100] In some embodiments, at least one Sp in the compound of Formula IV is selected from a polymerizable group of Formula V or Formula VI:

[0101]

[0102] wherein n is selected from any integer from 0 to 10;

[0103] Z4 is selected from a single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, an alkylene having 1-10 carbon atoms, an alkenylene having 2-10 carbon atoms or an alkynyl having 2-10 carbon atoms, one or more non-adjacent -CH2- in Z4 are unsubstituted or substituted with any of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- and -C≡C-, one or more H in Z4 are unsubstituted or substituted with F, Cl, Br, I.

[0104] In some embodiments, Formula I is selected from any one of Formula I-1 to Formula I-12:

[0105]

[0106] Preferably, Formula I is selected from any one of Formula I-2, I-6, I-8, I-10, I-11, I-12.

[0107] In some embodiments, Formula II is selected from any one of Formula II-1 to Formula II-3:

[0108]

[0109] In some embodiments, Formula II is selected from any one of Formula II-1-1 to Formula II-3-12:

[0110]

[0111] Preferably, Formula II is selected from any one of Formula II-1-2, II-1-3, II-1-4, II-1-6, II-1-8, II-1-10, II-2-3, II-2-4, II-2-5, II-2-6, II-2-7, II-2-8, II-2-9, II-3-2, II-3-4, II-3-5, II-3-7, II-3-9.

[0112] In some embodiments, Formula III is selected from any one of Formula III-1 to Formula III-3:

[0113]

[0114] In some embodiments, Formula III is selected from any one of Formula III-1-1 to Formula III-3-12:

[0115]

[0116] Preferably, Formula III is selected from any one of Formula III-1-1, II-1-2, II-1-9, II-2-2, II-2-4, II-2-5, II-2-9, II-3-2, II-3-4, II-3-9.

[0117] In some embodiments, Formula IV is selected from any one of Formula IV-1 to Formula IV-18:

[0118]

[0119]

[0120]

[0121] Preferably, Formula IV is selected from any one of Formula IV-1, IV-7.

[0122] In some embodiments, the liquid crystal composition comprises liquid crystal compounds and polymer monomers, the liquid crystal compounds comprise compounds represented by Formula I, Formula II and Formula III, and the polymer monomers comprise compounds represented by Formula IV. The polymer monomers form a polymer film through a polymerization reaction, the liquid crystal compounds comprise liquid crystal molecules with different birefringences (compounds represented by Formula I, Formula II and Formula III have different birefringences (Δn)), the liquid crystal molecules with different birefringences are randomly distributed in the polymer film, which determines the optical properties of the liquid crystal film layer 121, and the polymer anchors the liquid crystal molecules through intermolecular forces (such as van der Waals forces, hydrogen bonds) or crosslinking structures, so as to enhance the structural stability and performance persistence of the liquid crystal film layer 121.

[0123] In some embodiments, in the liquid crystal composition, the mass percentage of the liquid crystal compound is in the range of 0.1% to 20%, and the mass percentage of the polymer monomer is in the range of 5% to 30%. In this embodiment, when the content of each component in the liquid crystal composition is within the above range, the liquid crystal film layer 121 can have a good depolarization effect while maintaining a good transmittance. When the content of each component in the liquid crystal composition is lower than the above range, the depolarization function layer 120 can have a poor depolarization effect. When the content of each component in the liquid crystal composition is higher than the above range, the liquid crystal composition can have poor solubility, poor film uniformity, and a significantly reduced transmittance.

[0124] In the liquid crystal compound, the mass percentage of the compound represented by Formula I is in the range of 1% to 70%, the mass percentage of the compound represented by Formula II is in the range of 1% to 50%, and the mass percentage of the compound represented by Formula III is in the range of 1% to 50%, based on 100% of the total mass of the liquid crystal compound. In this embodiment, when the content of each component in the liquid crystal compound is within the above range, the liquid crystal film layer 121 can have a good depolarization effect while maintaining a good transmittance. When the content of each component in the liquid crystal compound is lower than the above range, the depolarization function layer 120 can have a poor depolarization effect. When the content of each component in the liquid crystal compound is higher than the above range, the liquid crystal composition can have poor solubility, poor film uniformity, and a significantly reduced transmittance.

[0125] In some embodiments, the liquid crystal composition further includes a first solvent, and the first solvent includes at least one of cyclohexanone, cyclopentanone, acetone, or ethyl acetate, but is not limited thereto.

[0126] In some embodiments, the alignment agent includes a diamine compound and an acid anhydride compound.

[0127] The diamine compound is selected from at least one of Formula VII-1 to Formula VII-4:

[0128]

[0129] The acid anhydride compound can be a tetracarboxylic dianhydride compound, and the acid anhydride compound is selected from at least one of Formula VIII-1 to Formula VIII-2:

[0130]

[0131] In the formula, Boc represents a tert-butyloxy carbonyl group.

[0132] Preferably, the diamine compound is selected from at least one of Formula VII-1 and Formula VII-4, and the acid anhydride compound is selected from Formula VIII-1.

[0133] In some embodiments, the alignment agent further includes a second solvent, which includes, but is not limited to, N-methyl-2-pyrrolidone (NMP), butyl cellosolve (BCS), etc.

[0134] In some embodiments, the mass percentage of the diamine compound in the alignment agent ranges from 0.1% to 10%, and the mass percentage of the anhydride compound ranges from 0.1% to 10%, to ensure that the alignment layer 122 has a good alignment effect. When the content of each component in the alignment agent is lower than the above range, it will affect the alignment effect of the alignment layer 122, and thus affect the depolarization effect of the depolarization functional layer 120; when the content of each component in the alignment agent is higher than the above range, it will lead to poor solubility of the alignment agent, poor film uniformity, and ultimately poor alignment effect.

[0135] In some embodiments, the alignment agent may also include other additives, such as silane coupling agents, but is not limited thereto. The silane coupling agent can enhance the adhesion between the alignment layer 122 and the substrate layer 110. The silane coupling agents used in this application include, but are not limited to, 3-epoxypropoxypropyltriethoxysilane.

[0136] This application also provides a display device 10, please refer to... Figure 7 The display device 10 of this application includes a display panel 200, a first polarizer 300, and an optical film 100 as described above. The first polarizer 300 is disposed on the light-emitting side of the display panel 200; the optical film 100 is disposed on the side of the first polarizer 300 away from the display panel 200.

[0137] The display panel 200 may be a liquid crystal display panel 200, including an array substrate 210, an opposing substrate 220 and a liquid crystal layer 230 located between the array substrate 210 and the opposing substrate 220, wherein the opposing substrate 220 may be located on the side of the liquid crystal layer 230 close to the first polarizer 300.

[0138] Furthermore, the display device 10 also includes a second polarizer 400 and a backlight 500, wherein the second polarizer 400 is disposed on the side of the display panel 200 away from the first polarizer 300, and the backlight 500 is disposed on the side of the second polarizer 400 away from the display panel 200.

[0139] In some embodiments, please refer to Figure 1 and Figure 7 The optical film 100 includes a substrate layer 110 and a depolarization functional layer 120 located on the side of the substrate layer 110 away from the first polarizer 300. In the thickness direction Z of the optical film 100, the depolarization functional layer 120 includes a first liquid crystal film layer, ..., the (N-1)th liquid crystal film layer and the Nth liquid crystal film layer, where N≥2, which are sequentially stacked along the direction away from the first polarizer 300.

[0140] wherein an angle between the alignment direction of the first liquid crystal film layer and the transmission axis of the first polarizer 300 is θ1, an angle between the alignment direction of the (N-1)th liquid crystal film layer and the transmission axis of the first polarizer 300 is θ N-1 , and an angle between the alignment direction of the Nth liquid crystal film layer and the transmission axis of the first polarizer 300 is θ N , wherein θ1≠…≠θ N-1 ≠θ N , 0°<θ1<90°, …, 0°<θ N-1 <90°, 0°<θ N <90°.

[0141] In some embodiments, referring to Figure 2 and Figure 7 , the optical film 100 further comprises a first alignment layer, a (N-1)th alignment layer, and an Nth alignment layer. An angle between the alignment direction of the first alignment layer and the transmission axis of the first polarizer 300 is θ1, an angle between the alignment direction of the (N-1)th alignment layer and the transmission axis of the first polarizer 300 is θ N-1 , and an angle between the alignment direction of the Nth alignment layer and the transmission axis of the first polarizer 300 is θ N , wherein θ1≠…≠θ N-1 ≠θ N , 0°<θ1<90°, …, 0°<θ N-1 <90°, 0°<θ N <90°.

[0142] In some embodiments, the difference between the angles between any two alignment layers 122 and the transmission axis of the first polarizer 300 is greater than or equal to 5°. For example, the relationship between the angle θ N between the alignment direction of the Nth alignment layer and the transmission axis of the first polarizer 300 and the angle θ N-1 between the alignment direction of the (N-1)th alignment layer and the transmission axis of the first polarizer 300 satisfies: |θ N -θ N-1 |≥5°, so as to ensure the difference between the alignment directions of different alignment layers 122, improve the randomness of the elliptically polarized light or circularly polarized light passing through the liquid crystal film layer 121, and improve the depolarization effect.

[0143] In the present application, the angles between the alignment directions of different alignment layers 122 and the transmission axis of the first polarizer 300 are different, which can improve the randomness of the elliptically polarized light or circularly polarized light passing through the depolarization functional layer 120, form circularly polarized light or elliptically polarized light with random distribution of light vectors, which is similar to natural light, and is beneficial to improving the eye protection effect.

[0144] In some embodiments, the depolarization functional layer 120 can include two or three liquid crystal film layers 121, i.e. N is 2 or 3, to have better depolarization effect while ensuring the optical film 100 has higher transmittance, to reduce the impact on the transmittance of the display device 10 while achieving the eye protection effect of the display device 10. Further, the depolarization functional layer 120 can also include two or three alignment layers 122, which are arranged one by one with the liquid crystal film layers 121.

[0145] In an embodiment, referring to Figure 3 , the depolarization functional layer 120 includes a first alignment layer 1221, a first liquid crystal film layer 1211, a second alignment layer 1222, and a second liquid crystal film layer 1212. The first alignment layer 1221 is arranged on the side of the substrate layer 110 away from the first polarizer 300; the first liquid crystal film layer 1211 is arranged on the side of the first alignment layer 1221 away from the substrate layer 110; the second alignment layer 1222 is arranged on the side of the first liquid crystal film layer 1211 away from the first alignment layer 1221; the second liquid crystal film layer 1212 is arranged on the side of the second alignment layer 1222 away from the first liquid crystal film layer 1211; wherein the angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1, and the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2, wherein 0° < θ1 < 90°, 0° < θ2 < 90°, and θ1 ≠ θ2. Further, θ2-θ1≥5°.

[0146] In another embodiment, referring to Figure 5The compensation function layer 120 includes a first alignment layer 1221, a first liquid crystal film layer 1211, a second alignment layer 1222, a second liquid crystal film layer 1212, a third alignment layer 1223, and a third liquid crystal film layer 1213. The first alignment layer 1221 is arranged on one side of the substrate layer 110; the first liquid crystal film layer 1211 is arranged on the side of the first alignment layer 1221 away from the substrate layer 110; the second alignment layer 1222 is arranged on the side of the first liquid crystal film layer 1211 away from the first alignment layer 1221; the second liquid crystal film layer 1212 is arranged on the side of the second alignment layer 1222 away from the first liquid crystal film layer 1211; the third alignment layer 1223 is arranged on the side of the second liquid crystal film layer 1212 away from the second alignment layer 1222; and the third liquid crystal film layer 1213 is arranged on the side of the third alignment layer 1223 away from the second liquid crystal film layer 1212. The angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1, the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2, and the angle between the alignment direction of the third alignment layer 1223 and the transmission axis of the first polarizer 300 is θ3, wherein 0° < θ1 < 90°, 0° < θ2 < 90°, 0° < θ3 < 90°, and θ1 ≠ θ2 ≠ θ3. Further, θ2-θ1≥5°, θ3-θ2≥5°, and θ3-θ1≥5°.

[0147] In the present application, the light emitted by the backlight 500 of the display device 10 passes through the second polarizer 400, the liquid crystal layer 230 of the display panel 200, and the first polarizer 300 in sequence to exit as linearly polarized light, and then passes through the optical film 100 to exit as elliptically polarized light or circularly polarized light similar to natural light. Since the optical film 100 includes multiple liquid crystal film layers 121 with different alignment directions, and the angle between the alignment direction of each liquid crystal film layer 121 and the transmission axis of the first polarizer 300 is different, and the angle range is within 0°-90°, the multiple liquid crystal film layers 121 with different alignment directions of the optical film 100 can perform phase delay on the linearly polarized light, and convert the linearly polarized light exiting from the first polarizer 300 into elliptically polarized light or circularly polarized light similar to natural light, thereby achieving the eye protection effect. Therefore, the display device 10 of the present application can effectively avoid damage to the viewer's fundus retina caused by the linearly polarized light exiting from the first polarizer 300.

[0148] In addition, the optical film 100 of the present application realizes the compensation effect while having small color deviation and little effect on the display effect of the display device 10.

[0149] The present application also provides a preparation method of the optical film 100, including the following steps:

[0150] 1. Preparation of liquid crystal composition

[0151] The compounds represented by Formula I, the compounds represented by Formula II, and the compounds represented by Formula III are weighed by a balance according to a predetermined mass percentage and mixed, wherein the order of the weighed addition is not particularly required, and generally, the compounds are weighed and mixed in the order of the melting point from low to high.

[0152] The mixture of the compounds represented by Formula I, the compounds represented by Formula II, and the compounds represented by Formula III is heated and stirred at a temperature of 60°C to 100°C to allow the three to be sufficiently dissolved and mixed.

[0153] The above mixture is cooled to room temperature, and a liquid crystal compound is obtained by packaging.

[0154] The compounds represented by Formula IV and the liquid crystal compound composed of the compounds represented by Formula I, the compounds represented by Formula II, and the compounds represented by Formula III are weighed by a balance according to a mass percentage, and added to a first solvent (cyclohexanone, cyclopentanone, acetone, or ethyl acetate, etc.) to be stirred to allow the components to be sufficiently dissolved and mixed.

[0155] The above mixture is cooled to room temperature, and a liquid crystal compound is obtained by packaging.

[0156] 2. Preparation of an alignment agent

[0157] 50 g of NMP is weighed by a balance, 0.897 g (3 mmol) of the compound represented by Formula VII-1 and 2.441 g (10 mmol) of the compound represented by Formula VII-4 are added and sufficiently stirred and dissolved, 2.744 g (14 mmol) of the compound represented by Formula VIII-1 is weighed and added to the above solution, and the mixture is uniformly mixed by stirring at 60°C for 12 hours to obtain a polyamic acid solution.

[0158] 30 g of the above polyamic acid solution is weighed by a balance, 7 g of NMP, 10 g of BCS (butyl cellosolve), and 3 g of 3-glycidoxypropyltriethoxysilane are added, and the solution is uniformly mixed by stirring, and an alignment agent is obtained by packaging.

[0159] 3. Preparation of an optical film 100

[0160] The above alignment agent is coated or spin-coated on the substrate layer 110.

[0161] The uniformly coated alignment agent layer is pre-baked and post-baked to obtain an alignment film, wherein the pre-baking temperature is 80°C, the time is 2 min, the post-baking temperature is 230°C, the time is 30 min, and the dry film thickness ranges from 80 to 100 nm.

[0162] The alignment film is subjected to UV alignment to obtain an alignment layer 122, wherein the wavelength of the UV alignment light is 254 nm, and the included angle between the alignment direction of the alignment layer 122 and the transmission axis direction of the first polarizer 300 is θ N , satisfying 0° < θ N < 90°.

[0163] The liquid crystal composition is coated or spin-coated on the alignment layer 122, wherein the wet film thickness ranges from 3 μm to 20 μm.

[0164] The uniformly coated sample is subjected to pre-baking at a temperature ranging from 40 °C to 130 °C, wherein the baking time ranges from 1 min to 10 min.

[0165] The pre-baked sample is subjected to UV curing, wherein the wavelength of the UV curing light is 313 nm and 365 nm, and the UV curing time ranges from 1 min to 50 min.

[0166] The UV-cured sample is subjected to post-baking at a temperature ranging from 40 °C to 130 °C; wherein the baking time ranges from 2 min to 60 min.

[0167] The above alignment layer 122 and liquid crystal composition coating or spin-coating process is repeated to realize the combination of two or three alignment layers 122 and liquid crystal film layers 121; and

[0168] The sample is cooled to room temperature to obtain the target optical film 100.

[0169] It should be noted that when the prepared optical film 100 includes two alignment layers 122 and two liquid crystal film layers 121, the alignment direction of the second alignment layer 1222 is different from the alignment direction of the first alignment layer 1221, or when the prepared optical film 100 includes three alignment layers 122 and three liquid crystal film layers 121, the alignment direction of the third alignment layer 1223, the alignment direction of the second alignment layer 1222 and the alignment direction of the first alignment layer 1221 are all different.

[0170] The optical film 100 and the display device 10 of the present application are further described below through Examples 1 to 4 and Comparative Examples. It can be understood that the examples of the present application are only described by taking Examples 1 to 4 as examples, and the protection scope of the present application is not limited thereto.

[0171] Among them, the four optical films 100 provided in Examples 1 to 4 are all made by using the above preparation process, and the structure of the optical film 100 can be referred to Figure 3 and Figure 5 . Specifically, the structural formula and the proportion of the liquid crystal composition used in the preparation process of the optical film 100 provided in Examples 1 to 4 are shown in Tables 1 to 4.

[0172] Example 1

[0173] The optical film 100 provided in Example 1 of the present application includes two alignment layers 122 and two liquid crystal film layers 121, the structure of which is shown in Figure 3 The first liquid crystal film layer 1211 and the second liquid crystal film layer 1212 are prepared by the method described above, wherein the first liquid crystal film layer 1211 and the second liquid crystal film layer 1212 are prepared by using the liquid crystal composition and the ratio shown in Table 1; the first alignment layer 1221 and the second alignment layer 1222 are prepared by the method described above, wherein the angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1=30°, and the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2=60°.

[0174] Table 1 Structural formula and ratio of the liquid crystal composition corresponding to Example 1

[0175]

[0176] Example 2

[0177] The optical film 100 provided in Example 2 of the present application includes two alignment layers 122 and two liquid crystal film layers 121, the structure of which is shown in Figure 3 The first liquid crystal film layer 1211 and the second liquid crystal film layer 1212 are prepared by the method described above, wherein the first liquid crystal film layer 1211 and the second liquid crystal film layer 1212 are prepared by using the liquid crystal composition and the ratio shown in Table 2; the first alignment layer 1221 and the second alignment layer 1222 are prepared by the method described above, wherein the angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1=30°, and the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2=60°.

[0178] Table 2 Structural formula and ratio of the liquid crystal composition corresponding to Example 2

[0179]

[0180] Example 3

[0181] The optical film 100 provided in Example 3 of the present application includes three alignment layers 122 and three liquid crystal film layers 121, the structure of which is shown in Figure 5The first liquid crystal film layer 1211, the second liquid crystal film layer 1212, and the third liquid crystal film layer 1213 are prepared by using the preparation method of the liquid crystal film layer 121, wherein the first liquid crystal film layer 1211, the second liquid crystal film layer 1212, and the third liquid crystal film layer 1213 all use the liquid crystal composition and the proportion shown in Table 3; the first alignment layer 1221, the second alignment layer 1222, and the third alignment layer 1223 are prepared by using the preparation method of the alignment layer 122, wherein the angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1=20°, the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2=45°, and the angle between the alignment direction of the third alignment layer 1223 and the transmission axis of the first polarizer 300 is θ3=65°.

[0182] Table 3: Structural formula and proportion of the liquid crystal composition corresponding to Example 3

[0183]

[0184] Example 4

[0185] The depolarization function layer 120 of the optical film 100 provided by Example 4 of the present application includes three alignment layers 122 and three liquid crystal film layers 121, and the structure is referred to Figure 5 The first liquid crystal film layer 1211, the second liquid crystal film layer 1212, and the third liquid crystal film layer 1213 are prepared by using the preparation method of the liquid crystal film layer 121, wherein the first liquid crystal film layer 1211, the second liquid crystal film layer 1212, and the third liquid crystal film layer 1213 all use the liquid crystal composition and the proportion shown in Table 4; the first alignment layer 1221, the second alignment layer 1222, and the third alignment layer 1223 are prepared by using the preparation method of the alignment layer 122, wherein the angle between the alignment direction of the first alignment layer 1221 and the transmission axis of the first polarizer 300 is θ1=20°, the angle between the alignment direction of the second alignment layer 1222 and the transmission axis of the first polarizer 300 is θ2=45°, and the angle between the alignment direction of the third alignment layer 1223 and the transmission axis of the first polarizer 300 is θ3=65°.

[0186] Table 4: Structural formula and proportion of the liquid crystal composition corresponding to Example 4

[0187]

[0188] Comparative Example

[0189] In the comparative example, a 1 / 4 wave plate is used instead of the optical film 100 of the present application. In the structure of the display device 10 of the comparative example, the 1 / 4 wave plate is arranged on the side of the first polarizer 300 away from the display panel 200.

[0190] The application examples also test the optical performance of the four optical films 100 provided by examples 1 to 4 and the 1 / 4 wave plate of the comparative example, and the test results are shown in Table 5. Among them, L max and L min respectively represent the maximum brightness and the minimum brightness, L max / Lmin The numerical size is used to reflect the brightness uniformity, and the value closer to 1 indicates that the brightness uniformity is better; the polarization degree is used to reflect the depolarization effect, and the smaller the polarization degree indicates that the depolarization effect is better; the transmittance is used to reflect the display brightness, and the larger the transmittance indicates that the display brightness is larger; ΔCIE-x and ΔCIE-y are used to reflect the color deviation degree, and the larger the difference, the more significant the color deviation.

[0191] As an example, in the optical films 100 provided by examples 1 to 4, the material of the substrate layer 110 is selected from PET.

[0192] As shown in Figure 8 , the test process of the optical performance is as follows: keep the relative positions of the backlight 500, the second polarizer 400 and the optical film 100 (or the 1 / 4 wave plate) fixed; rotate the first polarizer 300 at 0°-180°, test the brightness change value through the detector 600 above the first polarizer 300, and record the maximum and minimum brightness.

[0193] Table 5 Optical performance of the optical films 100 provided by examples 1 to 4 and the comparative example

[0194]

[0195] From the brightness value, polarization degree and transmittance in Table 5, the L max / Lmin value of the four optical films 100 provided by examples 1 to 4 of the application is close to 1, indicating that the brightness uniformity of the optical film 100 is good; the polarization degree is less than or equal to 11.0%, the polarization degree is relatively low, indicating that the depolarization effect of the optical film 100 is good; the transmittance is greater than or equal to 87%, the transmittance is relatively high, indicating that the light transmittance of the optical film 100 is good; when the four optical films 100 are applied to the display device 10, the depolarization effect can be effectively achieved, and the negative impact on the light transmittance and brightness can be avoided.

[0196] In addition, from the ΔCIE-x and ΔCIE-y data in Table 5, when the conventional 1 / 4 wave plate is used on the light exit side of the first polarizer 300 in the comparative example, the color deviation is serious because the 1 / 4 wave plate has wavelength selectivity; and the ΔCIE-x and ΔCIE-y of the four optical films 100 provided by examples 1 to 4 of the application are smaller, indicating that the color deviation of the optical film 100 is small, and the impact on the display effect of the display device 10 is small.

[0197] The application provides an optical film, an optical film material and a display device, the optical film comprises a depolarization functional layer, the depolarization functional layer comprises N liquid crystal film layers stacked along the thickness direction of the optical film, wherein N is greater than or equal to 2, each liquid crystal film layer has an independent alignment direction, and the alignment directions of any two liquid crystal film layers are different. Since the depolarization functional layer comprises multiple liquid crystal film layers, and the alignment directions of the multiple liquid crystal film layers are different, when linearly polarized light passes through the multiple liquid crystal film layers in sequence, the linearly polarized light will undergo “multi-layer polarization state modulation”, so that the linearly polarized light is finally converted into elliptically polarized light or circularly polarized light with random distribution of light vectors, and the depolarization effect is realized. When the above optical film is applied to the display device, the linearly polarized light emitted by the polaroid can be converted into elliptically polarized light or circularly polarized light similar to natural light, so that damage to the retina of the viewer's fundus is avoided, and the eye protection effect is achieved.

[0198] In the description of the present application, the terms “first” and “second” are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as “first” and “second” can explicitly or implicitly include one or more features. In the description of the present application, the meaning of “multiple” is two or more, unless otherwise specifically limited.

[0199] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0200] The embodiments, implementation manners and related technical features of the present application can be combined, replaced or modified without conflict.

[0201] The above is only a preferred embodiment of the present application, and does not limit the present application in any form, but any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiment, still belongs to the scope of the technical solution of the present application.

Claims

1. An optical film characterized by, The optical film comprises: a substrate layer; a depolarization functional layer disposed on one side of the substrate layer, the depolarization functional layer comprising N layers of liquid crystal film layers, the N layers of liquid crystal film layers being stacked along the thickness direction of the optical film, N≥2; wherein the alignment directions of any two layers of the liquid crystal film layers are different, and the optical film is configured to convert linearly polarized light incident on the optical film into elliptically polarized light and / or circularly polarized light with random distribution of light vectors.

2. The optical film of claim 1, wherein, The depolarization functional layer further comprises N layers of alignment layers, the N layers of alignment layers being disposed one-to-one corresponding to the N layers of liquid crystal film layers; wherein the Nth alignment layer is disposed on one side of the Nth liquid crystal film layer, and the Nth alignment layer is configured to align liquid crystal molecules in the Nth liquid crystal film layer; the alignment directions of any two layers of the alignment layers are different.

3. The optical film of claim 2, wherein, The depolarization functional layer comprises: a first alignment layer disposed on one side of the substrate layer; a first liquid crystal film layer disposed on one side of the first alignment layer away from the substrate layer; a second alignment layer disposed on one side of the first liquid crystal film layer away from the first alignment layer; a second liquid crystal film layer disposed on one side of the second alignment layer away from the first liquid crystal film layer; wherein the alignment direction of the first alignment layer is different from the alignment direction of the second alignment layer.

4. The optical film of claim 3, wherein, The depolarization functional layer further comprises: a third alignment layer disposed on one side of the second liquid crystal film layer away from the second alignment layer; a third liquid crystal film layer disposed on one side of the third alignment layer away from the second liquid crystal film layer; wherein the alignment direction of the third alignment layer is different from the alignment direction of the first alignment layer and the alignment direction of the second alignment layer.

5. An optical film material characterized by, The optical film material is used to form the optical film according to any one of claims 1 to 4; The optical film material comprises a liquid crystal composition used to form the liquid crystal film layers, wherein the liquid crystal composition comprises one or more compounds represented by formula I, one or more compounds represented by formula II, one or more compounds represented by formula III, and one or more compounds represented by formula IV: wherein R1, R2, R3, R4, R5 and R6 are selected from -H, -F, -Cl, -Br, -CN, -SCN, -NCS, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkynyl having 2-10 carbon atoms or alkynyloxy having 2-10 carbon atoms, the terminal groups of R1, R2, R3, R4, R5 and R6 are unsubstituted or substituted with -CN or -CF3, one or more non-adjacent -CH2- in R1, R2, R3, R4, R5 and R6 are unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C- and the heteroatoms are not directly bonded, one or more H in R1, R2, R3, R4, R5 and R6 are unsubstituted or substituted with F, Cl, Br, I; Z1, Z2 and Z3 are selected from a single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, alkylene having 1-10 carbon atoms, alkenylene having 2-10 carbon atoms or alkynylene having 2-10 carbon atoms, one or more non-adjacent -CH2- in Z1, Z2 and Z3 are unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- or -C≡C-, one or more H in Z1, Z2 and Z3 are unsubstituted or substituted with F, Cl, Br or I; one or more -CH2- not adjacent to one another in wherein one or more -CH2- not adjacent to one another in are not substituted or are substituted with -O-, one or more H are not substituted or are substituted with F, Cl, Br, or I; the H on the benzene ring of the compound represented by formula IV is unsubstituted or substituted with F, Cl, Br, CN, SCN, NCS, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkynyl having 2-10 carbon atoms or alkynyloxy having 2-10 carbon atoms; L is selected from H, F, Cl, CF3, Sp, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkynyl having 2-10 carbon atoms, alkynyloxy having 2-10 carbon atoms, cycloalkane having 3-10 carbon atoms or aromatic ring having 3-10 carbon atoms, one or more non-adjacent -CH2- in L is unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CH2CH2-, -(CH2)3-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, one or more H in L is unsubstituted or substituted with F, Cl, Br or I; a and b are selected from 0, 1 or 2, and a+b≥1; c and m are selected from 0, 1 or 2; Sp is selected from branched or unbranched ether, alkyl, alkoxy, alkenyl, alkenyloxy or polymerizable group; at least one Sp in the compound represented by formula IV is selected from formula V or formula VI: wherein n is selected from any one integer from 0 to 10; Z4 is selected from single bond, -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, alkylene having 1-10 carbon atoms, alkenylene having 2-10 carbon atoms or alkynyl having 2-10 carbon atoms, one or more non-adjacent -CH2- in Z4 is unsubstituted or substituted with any one of -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O-, -OCH2-, -CH=CH- and -C≡C-, one or more H in Z4 is unsubstituted or substituted with F, Cl, Br, I.

6. The optical film material of claim 5, wherein, formula I is selected from any one of formula I-1 to formula I-12: formula II is selected from any one of formula II-1 to formula II-3: formula III is selected from any one of formula III-1 to formula III-3: formula IV is selected from any one of formula IV-1 to formula IV-18:

7. The optical film material of claim 5, wherein, the liquid crystal composition comprises liquid crystal compounds and polymer monomers, wherein the liquid crystal compounds comprise compounds represented by formula I, formula II and formula III, and the polymer monomers comprise compounds represented by formula IV; in the liquid crystal composition, the mass percentage of the liquid crystal compounds ranges from 0.1% to 20%, and the mass percentage of the polymer monomers ranges from 5% to 30%; in the liquid crystal compounds, the mass percentage of the compound represented by formula I ranges from 1% to 70%, the mass percentage of the compound represented by formula II ranges from 1% to 50%, and the mass percentage of the compound represented by formula III ranges from 1% to 50%.

8. The optical film material of claim 5, wherein, The optical film material further comprises an alignment agent for forming the alignment layer, the alignment agent comprising a diamine compound and an anhydride compound; The diamine compound is selected from at least one of VII-1 to VII-4: The anhydride compound is selected from at least one of VIII-1 to VIII-2: Wherein, Boc represents tert-butyloxy carbonyl.

9. The optical film material of claim 8, wherein, The mass percentage of the diamine compound in the alignment agent ranges from 0.1% to 10%, and the mass percentage of the anhydride compound ranges from 0.1% to 10%.

10. A display device, characterized by comprising: The display device comprises: a display panel; a first polarizer disposed on the light-emitting side of the display panel; and The optical film according to any one of claims 1 to 4 is disposed on the side of the first polarizer away from the display panel.

11. The display device according to claim 10, wherein an angle between the alignment direction of the first liquid crystal film layer and the transmission axis of the first polarizing plate is θ1, an angle between the alignment direction of the second liquid crystal film layer and the transmission axis of the first polarizing plate is θ2, an angle between the alignment direction of the (N-1)th liquid crystal film layer and the transmission axis of the first polarizing plate is θ N-1 , and an angle between the alignment direction of the Nth liquid crystal film layer and the transmission axis of the first polarizing plate is θ N . an angle between the alignment direction of the first liquid crystal film layer and the transmission axis of the first polarizing plate is θ1, an angle between the alignment direction of the second liquid crystal film layer and the transmission axis of the first polarizing plate is θ2, an angle between the alignment direction of the (N-1)th liquid crystal film layer and the transmission axis of the first polarizing plate is θ N-1 ≠θ N , 0° < θ1 < 90°, 0° < θ N-1 < 90°, 0° < θ N < 90°.

12. The display device according to claim 10, wherein The optical film adopts the optical film as claimed in claim 2, wherein the included angle between the alignment direction of the first alignment layer and the light transmission axis of the first polarizing plate is θ1, the included angle between the alignment direction of the (N-1)th alignment layer and the light transmission axis of the first polarizing plate is θ N-1 , and the included angle between the alignment direction of the Nth alignment layer and the light transmission axis of the first polarizing plate is θ N . θ1≠…≠θ N-1 ≠θ N , 0°<θ1<90°, 0°<θ N-1 <90°, and 0°<θ N <90°.

13. The display device of claim 10, wherein, |θ N -θ N-1 |≥5°.

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