Photocuring body holographic polymer material, grating and preparation method thereof

Abstract

The embodiment of the invention provides a photocuring body holographic polymer material, a grating and a preparation method of the photocuring body holographic polymer material, and the photocuring body holographic polymer material comprises the following components in percentage by mass: 20-45% of liquid crystal; 0.01 to 2% of a photoinitiator; 0.5%-5% of a co-initiator; 5%-40% of a first monomer; 10%-50% of a second monomer; 1%-10% of a third monomer; the first monomer and / or the second monomer and / or the third monomer contains ethyoxyl. According to the technical scheme provided by the embodiment of the invention, the compatibility of the liquid crystal with the monomer and the polymer is improved by selecting the ethyoxyl-containing monomer, so that the problem that the haze is increased to influence the imaging effect due to the poor compatibility of the liquid crystal with the monomer and the polymer caused by the increase of the liquid crystal proportion when the polymer material with high diffraction efficiency is prepared is solved; the haze is reduced while the high diffraction efficiency is ensured, and the imaging effect is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of grating waveguide lens materials, and in particular to photocurable holographic polymer materials, gratings and preparation methods thereof. Background Art

[0002] Augmented Reality (AR), also known as augmented reality, can integrate real-world information with virtual-world information. The AR industry has developed rapidly in recent years and is increasingly used in various industries, such as education, training, medical treatment, design, advertising, etc. The core of AR optical display is optical waveguide, which can be realized by diffraction grating. Volume holographic grating is a diffraction grating used for diffraction optical waveguide.

[0003] AR glasses waveguide lenses have certain requirements for diffraction efficiency, especially holographic waveguide lenses. What affects the diffraction efficiency is the refractive index modulation. With the improvement of diffraction efficiency, the haze of the volume holographic grating tends to increase, affecting the transmittance of the material and affecting the imaging effect. The haze of the volume holographic grating prepared from the existing photocurable polymer material is not low enough. Often when the diffraction efficiency that meets the imaging requirements is reached, the actual effect is affected due to the high haze. Therefore, we need a photocurable polymer and a volume holographic grating that meets a certain diffraction efficiency and has a sufficiently low haze to be used in mixed reality glasses waveguide lenses. In addition, the photocurable volume holographic material in the prior art also contains solvents, which will cause certain damage to the environment. Summary of the invention

[0004] The embodiment of the present invention provides a photocurable holographic polymer material, a grating and a preparation method thereof, which can improve the diffraction efficiency and reduce the haze at the same time by selecting a monomer containing ethoxy groups.

[0005] In a first aspect, an embodiment of the present invention provides a photocurable holographic polymer material, which comprises, by mass percentage:

[0006]

[0007] The first monomer and / or the second monomer and / or the third monomer contain an ethoxy group.

[0008] Optionally, the first monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, tetrahydrofurfuryl acrylate and benzyl methacrylate.

[0009] Optionally, the second monomer is selected from one or more of cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate (n=13), polyethylene glycol diacrylate (n=9), polyethylene glycol diacrylate (n=5), tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4 (ethoxy) bisphenol A dimethacrylate, neopentyl glycol diacrylate, and 1,3-butanediol dimethacrylate.

[0010] Optionally, the third monomer is selected from one or more of ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

[0011] Optionally, the liquid crystal is selected from one or more of RDP-A4899, RDP-A4901, BL087, MLC6882, TL213 and P0616A.

[0012] Optionally, the photoinitiator is selected from one or more of Lucirin TPO, camphorquinone, Irgacure 784, thioacridone, rhodamine B, eosin, rose Bengal and QLCURE-BCIM.

[0013] Optionally, the co-initiator is selected from one or more of N-phenylglycine, N,N-dimethylhexanamide and benzoyl peroxide.

[0014] In a second aspect, an embodiment of the present invention further provides a method for preparing a volume holographic grating device, comprising:

[0015] Filling the photocurable holographic polymer material according to any one of the first aspects of the present invention into a liquid crystal cell;

[0016] The liquid crystal box is placed under the interference light field of a double-beam light source for interference exposure.

[0017] Optionally, the thickness of the photocurable holographic polymer material in the liquid crystal box is 3-10 μm.

[0018] Optionally, the angle between the dual-beam light sources is 35°-60°.

[0019] Optionally, the interference exposure time under the interference light field of the dual-beam light source is 1-10 min, and the irradiation power is 1-20 mW / cm 2 .

[0020] In a third aspect, an embodiment of the present invention further provides a volume holographic grating device, which is prepared by the preparation method described in any one of the second aspects of the present invention.

[0021] The embodiment of the present invention provides a photocurable holographic polymer material, a grating and a preparation method thereof. The photocurable holographic polymer material includes, by mass percentage: 20%-45% liquid crystal; 0.01-2% photoinitiator; 0.5%-5% coinitiator; 5%-40% first monomer; 10%-50% second monomer; 1%-10% third monomer; and the first monomer and / or the second monomer and / or the third monomer contain ethoxy groups. The technical solution of the embodiment of the present invention improves the compatibility of liquid crystal with monomers and polymers by selecting monomers containing ethoxy groups, thereby solving the problem that when a polymer material with high diffraction efficiency is prepared, the increase in the proportion of liquid crystal leads to poor compatibility of liquid crystal with monomers and polymers, resulting in increased haze and affecting the imaging effect. The haze is reduced while ensuring high diffraction efficiency, thereby improving the imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic flow chart of a method for preparing a volume holographic grating device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0024] It should be mentioned before discussing exemplary embodiments in more detail that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe various operations (or steps) as sequential processes, many operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of various operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. The process can correspond to methods, functions, procedures, subroutines, subprograms, etc. In addition, the embodiments in the present invention and the features in the embodiments can be combined with each other without conflict.

[0025] The term “including” and its variations used in the present invention are open inclusions, that is, “including but not limited to.” The term “based on” means “based at least in part on.” The term “one embodiment” means “at least one embodiment.”

[0026] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding contents, and are not used to limit the order or interdependence.

[0027] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0028] A photocurable holographic polymer material, comprising, by mass percentage: 20%-45% liquid crystal; 0.01%-2% photoinitiator; 0.5%-5% coinitiator; 5%-40% first monomer; 10%-50% second monomer; 1%-10% third monomer;

[0029] The first monomer and / or the second monomer and / or the third monomer contains an ethoxy group.

[0030] Specifically, when making a polymer material with high diffraction efficiency, the photoinitiator and the co-initiator can initiate a chain free radical / ion polymerization reaction among the first monomer, the second monomer and the third monomer; the first monomer, as a diluent, has a low viscosity and can play a role in growing the molecular chain of the polymer; the second monomer and the third monomer can make the oligomers cross-link rapidly to form a fixed structure. By adjusting the ratio of the first, second and third monomers, the viscosity of the material can be adjusted to make it suitable for processing. However, if the diffraction efficiency of the polymer material is to be increased, the proportion of liquid crystal is often increased, and the increase in the proportion of liquid crystal will make the compatibility of the monomer, polymer and liquid crystal poor, thereby increasing the haze. If the compatibility of the monomer, polymer and liquid crystal is increased by adding a solvent, the solvent contains volatile organic matter, which does not meet the environmental protection requirements. That is to say, the present invention selects a monomer containing ethoxy groups. When the increase in the proportion of liquid crystal reduces the compatibility with the polymer and monomer and causes the haze to increase, the addition of ethoxy groups can increase the compatibility between the monomer, polymer and liquid crystal without adding a solvent, thereby reducing the haze of the polymer material formed by them.

[0031] The embodiment of the present invention provides a photocurable holographic polymer material, which includes, by mass percentage: 20%-45% liquid crystal; 0.01%-2% photoinitiator; 0.5%-5% coinitiator; 5%-40% first monomer; 10%-50% second monomer; 1%-10% third monomer; the first monomer and / or the second monomer and / or the third monomer contain ethoxy groups. The technical solution of the embodiment of the present invention improves the compatibility of liquid crystal with monomers and polymers by selecting monomers containing ethoxy groups, thereby solving the problem that when preparing polymer materials with high diffraction efficiency, the increase in the proportion of liquid crystal leads to poor compatibility of liquid crystal with monomers and polymers, resulting in increased haze and affecting imaging effects, and reduces haze while ensuring high diffraction efficiency, thereby improving imaging effects.

[0032] In an optional embodiment, the first monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, tetrahydrofurfuryl acrylate and benzyl methacrylate.

[0033] In an optional embodiment, the second monomer is selected from one or more of cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate (n=13), polyethylene glycol diacrylate (n=9), polyethylene glycol diacrylate (n=5), tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4 (ethoxy) bisphenol A dimethacrylate, neopentyl glycol diacrylate, and 1,3-butanediol dimethacrylate.

[0034] In an optional embodiment, the third monomer is selected from one or more of ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

[0035] In an optional embodiment, the liquid crystal is selected from one or more of RDP-A4899, RDP-A4901, BL087, MLC6882, TL213 and P0616A.

[0036] In an optional embodiment, the photoinitiator is selected from one or more of Lucirin TPO, camphorquinone, Irgacure 784, thioacridone, rhodamine B, eosin, rose Bengal and QLCURE-BCIM. It should be understood that the photoinitiator is a photoinitiator that is sensitive to the laser wavelength that excites the first monomer, the second monomer and the third monomer to undergo a photopolymerization reaction.

[0037] The co-initiator is selected from one or more of N-phenylglycine, N,N-dimethylhexanamide and benzoyl peroxide.

[0038] Specifically, in the holographic photopolymer material of the embodiment of the present invention, each component material is selected from one or more of the above-mentioned materials in terms of mass percentage, and acrylic monomers with different functionalities are added, wherein the viscosity of the first monomer, the second monomer and the third monomer are different. The system viscosity of the material is very suitable for processing by adjusting the proportion. During the processing, the monomers are easy to move, and the double bond structure on each monomer molecule can be easily involved in the reaction, thereby improving the conversion rate of the double bonds. The increase in the conversion rate of the double bonds will increase the refractive index of the material itself, thereby improving the refractive index modulation of the material and improving the diffraction efficiency; at the same time, due to the increase in the proportion of liquid crystal, its compatibility with polymers and monomers becomes lower, which will lead to an increase in haze, but the addition of ethoxy groups can improve the compatibility of liquid crystals with polymers and monomers without using solvents, thereby ensuring high diffraction efficiency and low haze while avoiding the addition of solvents, because the volatile organic matter in the solvent will cause harm to the environment.

[0039] Figure 1 A schematic diagram of a method for preparing a volume holographic grating device according to an embodiment of the present invention is provided. Figure 1 ,include:

[0040] S110, filling the photocurable holographic polymer material into the liquid crystal box.

[0041] The thickness of the photocurable holographic polymer material in the liquid crystal box is 3-10 μm. Specifically, after the photocurable holographic polymer material is prepared by using ethoxy monomers, it is filled into the liquid crystal box.

[0042] S120, placing the liquid crystal box under the interference light field of the double-beam light source for interference exposure.

[0043] The angle between the two beam light sources is 35°-60°, the interference exposure time under the interference light field of the two beam light sources is 1-10 min, and the irradiation power is 1-20 mW / cm 2 , and a volume holographic grating device is obtained.

[0044] Based on the same concept, an embodiment of the present invention further provides a volume holographic grating device, which includes any one of the photocurable volume holographic polymer materials provided in the embodiments of the present invention, and because the volume holographic grating device includes the photocurable volume holographic polymer material provided in the embodiments of the present invention, it has the same or similar beneficial effects as the photocurable volume holographic polymer material provided in the embodiments of the present invention.

[0045] The following is further described in conjunction with specific examples and comparative examples. The raw materials involved in the following specific examples, unless otherwise specified, can all be sourced from commercial sources, and the instruments used, unless otherwise specified, can all be sourced from commercial sources.

[0046] Embodiment 1

[0047] In the embodiment of the present invention, the liquid crystal is MLC6882, with a mass percentage of 38%; the photoinitiator is rhodamine B, with a mass percentage of 0.3%; the co-initiator is N-phenylglycine, with a mass percentage of 2%; the first monomer is isobornyl acrylate, with a mass percentage of 17%; the second monomer is polyethylene glycol diacrylate (n=5), with a mass percentage of 5% and tripropylene glycol diacrylate with a mass percentage of 32%; the third monomer is trimethylolpropane triacrylate with a mass percentage of 5.7%.

[0048] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0049] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0050] The diffraction efficiency was measured to be 61.3% and the haze was 0.8%.

[0051] Embodiment 2

[0052] In the embodiment of the present invention, the liquid crystal is selected from RDP-A4901 with a mass percentage of 37.4%; the photoinitiator is selected from Bengal rose red with a mass percentage of 1%; the coinitiator is selected from N-phenylglycine with a mass percentage of 3.2%; the first monomer is selected from ethyl methacrylate with a mass percentage of 19%; the second monomer is selected from 3-polyethylene glycol diacrylate (n=9) with a mass percentage of 5% and cyclohexanedimethanol diacrylate with a mass percentage of 31%; the third monomer is selected from trimethylolpropane triacrylate with a mass percentage of 3.4%.

[0053] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0054] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0055] The diffraction efficiency was measured to be 65.72% and the haze was 0.72%.

[0056] Embodiment 3

[0057] In the embodiment of the present invention, the liquid crystal is selected from RDP-A4901 with a mass percentage of 35.2%; the photoinitiator is selected from Bengal rose red with a mass percentage of 0.1%; the coinitiator is selected from N, N-dimethylhexanamide with a mass percentage of 3.6%; the first monomer is selected from tetrahydrofurfuryl acrylate with a mass percentage of 16%; the second monomer is selected from polyethylene glycol diacrylate (n=13) with a mass percentage of 5% and neopentyl glycol diacrylate with a mass percentage of 36%; the third monomer is selected from pentaerythritol triacrylate with a mass percentage of 4.1%.

[0058] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60°C for 30 minutes to obtain a uniformly dispersed photocurable holographic material. Then, pour the uniformly dispersed photocurable holographic material into a liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and perform interference exposure for 5 minutes. The irradiation power is 5mW / cm 2 , and a volume holographic grating device is obtained.

[0059] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0060] The diffraction efficiency was measured to be 62.55% and the haze was 0.61%.

[0061] Embodiment 4

[0062] In the embodiment of the present invention, the liquid crystal is BL087 with a mass percentage of 36%; the photoinitiator is rhodamine B with a mass percentage of 0.1%; the coinitiator is N-phenylglycine with a mass percentage of 4%; the first monomer is vinyl acetate with a mass percentage of 21%; the second monomer is polyethylene glycol diacrylate (n=5) with a mass percentage of 3% and ethylene glycol dimethacrylate with a mass percentage of 3%; the third monomer is dipentaerythritol hexaacrylate with a mass percentage of 5.2%.

[0063] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0064] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0065] The diffraction efficiency was measured to be 63.3% and the haze was 0.89%.

[0066] Embodiment 5

[0067] In the embodiment of the present invention, the liquid crystal is BL087 with a mass percentage of 39%; the photoinitiator is Bengal rose red with a mass percentage of 1.7%; the coinitiator is N, N-dimethylhexanamide with a mass percentage of 4.5%; the first monomer is isobornyl acrylate with a mass percentage of 14%; the second monomer is polyethylene glycol diacrylate (n=13) with a mass percentage of 7% and tripropylene glycol diacrylate with a mass percentage of 31%; the third monomer is trimethylolpropane triacrylate with a mass percentage of 2.8%.

[0068] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0069] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0070] The diffraction efficiency was measured to be 61.1% and the haze was 0.53%.

[0071] Comparative Example 1

[0072] In the embodiment of the present invention, the liquid crystal is selected from MLC6882 with a mass percentage of 39%; the photoinitiator is selected from rhodamine B with a mass percentage of 1%; the coinitiator is selected from N-phenylglycine with a mass percentage of 2%; the first monomer is selected from isobornyl acrylate with a mass percentage of 19%; the second monomer is selected from 1,3-butanediol dimethacrylate with a mass percentage of 5% and tripropylene glycol diacrylate with a mass percentage of 33%; the third monomer is selected from trimethylolpropane triacrylate with a mass percentage of 1%.

[0073] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0074] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0075] The diffraction efficiency was measured to be 60.8% and the haze was 4.1%.

[0076] Comparative Example 2

[0077] In the embodiment of the present invention, the liquid crystal is selected from RDP-A4901 with a mass percentage of 36%; the photoinitiator is selected from Bengal rose red with a mass percentage of 1.5%; the coinitiator is selected from N-phenylglycine with a mass percentage of 1.5%; the first monomer is selected from ethyl methacrylate with a mass percentage of 17%; the second monomer is selected from hydroxyethyl acrylate with a mass percentage of 5% and cyclohexanedimethanol diacrylate with a mass percentage of 33%; the third monomer is selected from trimethylolpropane triacrylate with a mass percentage of 6%.

[0078] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0079] The diffraction efficiency of the holographic grating device was tested by a grating diffraction efficiency tester. The haze was tested using a BYK4775 transmission haze meter.

[0080] The diffraction efficiency was measured to be 58.3% and the haze was 3.2%.

[0081] Comparative Example 3

[0082] In the embodiment of the present invention, the liquid crystal is selected from RDP-A4901 with a mass percentage of 38%; the photoinitiator is selected from Bengal rose red with a mass percentage of 0.3%; the coinitiator is selected from N, N-dimethylhexanamide with a mass percentage of 2.3%; the first monomer is selected from tetrahydrofurfuryl acrylate with a mass percentage of 10%; the second monomer is selected from ethylene glycol dimethacrylate with a mass percentage of 5% and neopentyl glycol diacrylate with a mass percentage of 36%; the third monomer is selected from pentaerythritol triacrylate with a mass percentage of 8.4%.

[0083] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersion equipment, and disperse them evenly at 60℃ for 30 minutes. Then pour the evenly dispersed photocurable holographic material into the liquid crystal box, and control the thickness of the liquid crystal box to be 10μm; then place it under the interference light field of a double-beam light source with an angle of 45°, and expose it for 5 minutes with an irradiation power of 5mW / cm 2 , and a volume holographic grating device is obtained.

[0084] The diffraction efficiency of the above holographic grating device is tested by a grating diffraction efficiency tester.

[0085] The haze was tested using a BYK 4775 haze meter.

[0086] The diffraction efficiency was measured to be 62.8% and the haze was 3.3%.

[0087] Specifically, through comparison of the above-mentioned embodiments and comparative examples, it can be found that the diffraction efficiency of the volume holographic grating device prepared in Examples 1-5 is higher than that of Comparative Examples 1-3. At the same time, the monomers in Examples 1-5 contain ethoxy groups, which increases the compatibility between the monomers, polymers and liquid crystals in the materials, thereby reducing the haze of the gratings formed by them, and the haze is significantly lower than the haze of the volume holographic grating device prepared in Comparative Examples 1-3 which does not contain ethoxy groups.

[0088] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A photocurable holographic polymer material, characterized in that: In terms of mass percentage, it includes: LCD 20%-45%; Photoinitiator 0.01-2%; Co-initiator 0.5%-5%; The first monomer is 5%-40%; The second monomer 10%-50%; The third monomer 1%-10%; The first monomer and / or the second monomer and / or the third monomer contain an ethoxy group.

2. The volume holographic polymer material according to claim 1, characterized in that: The first monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, tetrahydrofurfuryl acrylate and benzyl methacrylate.

3. The volume holographic polymer material according to claim 1, characterized in that: The second monomer is selected from one or more of cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate (n=13), polyethylene glycol diacrylate (n=9), polyethylene glycol diacrylate (n=5), tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4 (ethoxy) bisphenol A dimethacrylate, neopentyl glycol diacrylate, and 1,3-butanediol dimethacrylate.

4. The volume holographic polymer material according to claim 1, characterized in that: The third monomer is selected from one or more of ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

5. The volume holographic polymer material according to claim 1, characterized in that: The liquid crystal is selected from one or more of RDP-A4899, RDP-A4901, BL087, MLC6882, TL213 and P0616A.

6. The volume holographic polymer material according to claim 1, characterized in that: The photoinitiator is selected from one or more of Lucirin TPO, camphorquinone, Irgacure 784, thioacridone, rhodamine B, eosin, rose Bengal and QLCURE-BCIM.

7. The volume holographic polymer material according to claim 1, characterized in that: The co-initiator is selected from one or more of N-phenylglycine, N,N-dimethylhexanamide and benzoyl peroxide.

8. A method for preparing a volume holographic grating device, characterized in that: include: Filling the photocurable holographic polymer material according to any one of claims 1 to 7 into a liquid crystal cell; The liquid crystal box is placed under the interference light field of a double-beam light source for interference exposure.

9. The method for preparing a volume holographic grating device according to claim 8, characterized in that: The thickness of the photocurable holographic polymer material in the liquid crystal box is 3-10 μm.

10. The method for preparing a volume holographic grating device according to claim 8, characterized in that: The angle between the double-beam light sources is 35°-60°.

11. The method for preparing a volume holographic grating device according to claim 8, characterized in that: The interference exposure time under the interference light field of the double-beam light source is 1-10 minutes, and the irradiation power is 1-20mW / cm 2 .

12. A volume holographic grating device, characterized in that: Prepared by the preparation method according to any one of claims 8 to 11.

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