Photopolymer-type holographic recording medium and substrate processing method

Abstract

The invention discloses a photopolymer type holographic recording medium and a substrate processing method, and the method comprises the steps: providing a substrate which comprises a glass substrate or a resin substrate; providing a mixed solution of the photopolymer type holographic recording medium; performing hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate; uniformly distributing the mixed solution of the photopolymer type holographic recording medium on the surface of a substrate, and baking, so that the compound with a plurality of isocyanate reactive functional groups and the polyisocyanate group compound in the photopolymer type holographic recording medium react to generate film-forming resin; the hydroxyl group on the surface of the substrate participates in the reaction, and the film-forming resin is connected to the substrate in a covalent bond manner. In this way, the adhesion between the photopolymer layer and the substrate can be improved without increasing the complexity of subsequent process operations.

Description

Technical Field

[0001] The present application relates to the technical field of photopolymer materials, and in particular to a photopolymer holographic recording medium and a substrate processing method. Background Art

[0002] One of the technical routes for augmented reality (AR) glasses and head-up display (HUD) is to coat a photopolymer onto a glass or resin substrate, and then perform holographic exposure to obtain a volume holographic grating. The volume holographic grating of the device using this route may fall off as the device is used for a longer time, causing the device to lose its function. To solve the above problems, the current mainstream technical route is to first prepare a volume holographic grating by holographic exposure, and then bond it to a glass or resin substrate. This route requires an additional adhesive layer, and at the same time, the requirements for the bonding position accuracy of the volume holographic grating, the selection of the adhesive layer, the thickness accuracy of the adhesive layer, and the optical properties of the adhesive layer are relatively high, which increases the complexity of the production process. Summary of the invention

[0003] Based on this, the present application provides a photopolymer holographic recording medium and a substrate processing method, which can improve the adhesion between the photopolymer layer and the substrate without increasing the complexity of subsequent process operations.

[0004] In a first aspect, the present application provides a photopolymer holographic recording medium, which includes a compound having multiple isocyanate-reactive functional groups, a polyisocyanate-based compound, a polymerizable monomer, a photosensitive initiation system, a chain transfer agent, a catalyst, and an additive.

[0005] In a second aspect, the present application provides a substrate processing method, the method comprising:

[0006] Providing a substrate, wherein the substrate comprises a glass substrate or a resin substrate;

[0007] providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is the photopolymer holographic recording medium as described above;

[0008] Performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate;

[0009] The mixed solution of the photopolymer holographic recording medium is evenly distributed on the surface of the substrate and baked, so that the compound having multiple isocyanate reactive functional groups and the polyisocyanate compound in the photopolymer holographic recording medium react to form a film-forming resin, and the hydroxyl groups on the surface of the substrate participate in the reaction to connect the film-forming resin to the substrate in a covalent bond manner.

[0010] In a third aspect, the present application provides a substrate processing method, the method comprising:

[0011] Providing a substrate, wherein the substrate comprises a glass substrate or a resin substrate;

[0012] providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is the photopolymer holographic recording medium as described above;

[0013] Performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate;

[0014] Immersing the hydroxylated substrate in a silane coupling agent solution and allowing it to stand to generate polymerizable groups on the surface of the substrate, wherein the polymerizable groups can react with polymerizable monomers in the photopolymer holographic recording medium to generate polymers;

[0015] The mixed solution of the photopolymer holographic recording medium is uniformly distributed on the surface of the substrate and baked, so that the compound having multiple isocyanate reactive functional groups and the polyisocyanate compound in the photopolymer holographic recording medium react to form a film-forming resin, the hydroxyl groups on the surface of the substrate participate in the reaction and the film-forming resin is connected to the substrate in a covalent bond manner, and the polymerizable groups on the surface of the substrate react with the polymerizable monomer to form a polymer that is connected to the substrate in a covalent bond manner.

[0016] The embodiments of the present application provide a photopolymer holographic recording medium and a substrate processing method. Since the photopolymer holographic recording medium can react with the surface of a substrate having hydroxyl groups generated on the surface after treatment, or react with the surface of a substrate having hydroxyl groups and polymerizable groups generated on the surface after treatment, a volume holographic grating prepared by the photopolymer can be effectively adhered to the substrate without affecting the holographic recording performance of the photopolymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a process of an embodiment of a substrate processing method of the present application;

[0018] Figure 2 is a schematic flow chart of another embodiment of the substrate processing method of the present application;

[0019] Figure 3 This is the result of the 100-grid test of volume holographic grating 1;

[0020] Figure 4 This is a graph of the hundred-grid test results of the volume holographic grating 10;

[0021] Figure 5 This is a graph of the hundred-grid test results of Comparative Example 3;

[0022] Figure 6 This is a graph of the hundred-grid test results for comparative example 6. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0025] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present application, and have no special meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner.

[0026] In the digital age, augmented reality (AR) technology provides users with a new and intuitive interactive experience by superimposing virtual information on the real world. Currently, AR glasses and head-up displays (HUD) are the main entrances for users to interact with AR.

[0027] A diffraction grating is a type of grating that modulates the amplitude or phase (or both) of incident light in a periodic spatial manner through a regular structure. The most important application of a diffraction grating in optics is as a spectroscopic device, and is often used in monochromators and spectrometers.

[0028] One of the technical routes for AR glasses and HUD is to coat photopolymers onto glass or resin substrates, and then perform holographic exposure to produce volume holographic gratings. Equipment using this route may experience the possibility of volume holographic gratings falling off over time, causing the device to lose its function. To solve the above problems, the current mainstream technical route is to first prepare a volume holographic grating by holographic exposure, and then bond it to a glass or resin substrate. This route requires an additional adhesive layer, and at the same time, the requirements for the grating bonding position accuracy, the selection of the adhesive layer, the thickness accuracy of the adhesive layer, the optical properties of the adhesive layer, etc. are relatively high, which increases the complexity of the production process.

[0029] In order to solve the above-mentioned problems, the embodiments of the present application provide a photopolymer holographic recording medium and a substrate processing method. Since the photopolymer holographic recording medium can react with the surface of a substrate having hydroxyl groups generated on the surface after treatment, or react with the surface of a substrate having hydroxyl groups and polymerizable groups generated on the surface after treatment, the volume holographic grating prepared by the photopolymer can be effectively adhered to the substrate, and has no effect on the holographic recording performance of the photopolymer.

[0030] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0031] The embodiment of the present application provides a photopolymer holographic recording medium, which includes a compound having multiple isocyanate-reactive functional groups, a polyisocyanate-based compound, a polymerizable monomer, a photosensitive initiation system, a chain transfer agent, a catalyst, and an additive.

[0032] It should be noted that the photopolymer holographic recording medium material usually contains a low-refractive-index film-forming resin and a high-refractive-index writing monomer. In the embodiment of the present application, component a) a compound having multiple isocyanate-reactive functional groups and component b) a polyisocyanate-based compound can form a base resin, while component c) a polymerizable monomer is equivalent to a writing monomer.

[0033] In some embodiments, the mass ratio of component a) a compound having multiple isocyanate-reactive functional groups, component b) a polyisocyanate-based compound, component c) a polymerizable monomer, component d) a photosensitive initiator system, component e) a chain transfer agent, component f) a catalyst, and component g) an additive is 10 to 70:10 to 50:0.1 to 60:0.1 to 4:0.1 to 3:0.1 to 3:0.1 to 10.

[0034] In some embodiments, the photosensitive initiation system includes component h) a photosensitizer and component i) a photoinitiator. Photosensitizer is also called dye or photosensitizing dye.

[0035] In some embodiments, the mass ratio of the component h) photosensitizer to the component i) photoinitiator is 0.001-1:0.1-3.

[0036] Different wide-band responses can be achieved by adjusting the type of photosensitizer. It should be noted that when a photoinitiator with an adapted wavelength is selected in the raw material of the photopolymer type holographic recording medium, the photosensitizer may not be added.

[0037] Exemplarily, the photosensitizer is a dye having a high electron transfer efficiency under light, including but not limited to cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, benzylcycloalkane ketone compounds or any mixture of these compounds in any proportion.

[0038] For example, the photosensitizer includes one or more of new methylene blue, thionine, basic yellow, pinacol chloride, rhodamine 6G, gallocyanine, ethyl violet, Victoria blue R, lapis lazuli blue, methylene blue, Astrazon Orange G, Darrow red, pyrrole red Y, basic red 29, quinaldine red, crystal violet, ethyl violet, brilliant green, pyri11lium I, azure A, crystal violet white nitrile, malachite green white nitrile, etc.

[0039] The photoinitiator is an initiator that can be activated by light and initiate a polymerization reaction of the corresponding polymerizable groups, including but not limited to aromatic ketone compounds, benzoin and its derivatives, benzil ketal, acylphosphine oxide, aryl ammonium borate, chromium salts, aryl diazonium salts, onium salts, organometallic compounds or any mixture of these compounds in any proportion.

[0040] For example: the photoinitiator includes one or more of benzophenone, alkyl benzophenone, 4,4'-bis(dimethylamino)benzophenone, anthrone and halogenated benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxide, phenyl dihydroxyacetate, camphorquinone, α-aminoalkyl phenone, α,α-dialkoxyacetophenone, α-hydroxyalkyl phenone, triphenylhexyl borate tetrabutylammonium, tri-(3-fluorophenyl)hexyl borate tetrabutylammonium, tri-(3-chloro-4-methylphenyl)hexyl borate tetrabutylammonium, ferrocenyl compounds, iodonium salts, sulfonium salts, hexaarylbisimidazoles, etc.

[0041] In some embodiments, the isocyanate-reactive functional group is a hydroxyl group; the compound having multiple isocyanate-reactive functional groups includes a compound having a refractive index less than or equal to 1.55 and having two or more hydroxyl functional groups.

[0042] In some embodiments, the compound having multiple isocyanate reactive functional groups includes: tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200 to 2000, polycarbonate polyol, and polyether polyol.

[0043] In some embodiments, the polyisocyanate-based compound includes a compound having a refractive index less than or equal to 1.55 and having two or more isocyanate groups.

[0044] In some embodiments, the polyisocyanate-based compound includes hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene)isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0045] In some embodiments, the polymerizable monomer is selected from at least one of alkenyl naphthalene compounds, alkenyl anthracene compounds, alkenyl benzene compounds, acrylic compounds, methacrylic compounds, acrylate compounds, methacrylate compounds, N-vinyl pyrrole, N-vinyl carbazole, N-vinylimidazole, N-vinyl indole, N-vinyl pyrrolidone, and trans-N-3-ynyl butenyl carbazole.

[0046] Illustratively, the alkenylbenzene compound can be selected from styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene, and the like.

[0047] Exemplarily, the acrylic compound can be acrylic acid and its derivatives; Exemplarily, the acrylic ester compound can be selected from pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-di(2-thionaphthyl)2-butyl acrylate, phenoxyethoxyethyl acrylate, bisphenol A diacrylate, tetrabromobisphenol A diacrylate, 2-phenoxyethyl acrylate, benzyl acrylate, p-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate, p-bromophenyl acrylate, 2,4,6-tribromophenyl acrylate, propane-2,2-diylbis[(2,6-dibromo-4,1-phenylene)oxy(2-{[3,3,3-tri(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl] diacrylate, etc.

[0048] Exemplarily, the methacrylate compound can be selected from 2-phenoxyethyl methacrylate, benzyl methacrylate, p-bromophenyl methacrylate, p-chlorophenyl methacrylate, 2,4,6-trichlorophenyl methacrylate, pentabromophenyl methacrylate, pentachlorophenyl methacrylate, phenoxyethyl methacrylate, phenoxyethoxyethyl methacrylate, 1,4-di(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate, and the like.

[0049] For example, the alkenyl anthracene compound may be selected from 2-vinyl anthracene, 9-vinyl anthracene, and the like.

[0050] For example, the alkenyl naphthalene compound may be selected from 1-vinyl naphthalene, 2-vinyl naphthalene and the like.

[0051] In some embodiments, the chain transfer agent is a thiol compound, including but not limited to one or more of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, and the like.

[0052] In some embodiments, the catalyst is a tertiary amine catalyst and an organometallic catalyst, including but not limited to triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropylenediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts and bismuth carboxylate catalysts.

[0053] In some embodiments, the additive includes one or more of a defoamer, a leveling agent, a plasticizer, a UV absorber, a light stabilizer, and an antioxidant.

[0054] In some embodiments, when the additive includes a defoaming agent, the content of the defoaming agent is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0055] In some embodiments, when the additive includes a leveling agent, the content of the leveling agent is no more than 3% based on the total mass of the photopolymer holographic recording medium.

[0056] In some embodiments, when the additive includes a plasticizer, the content of the plasticizer is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0057] In some embodiments, when the additive includes an ultraviolet absorber, the content of the plasticizer is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0058] In some embodiments, when the additive includes an antioxidant, the content of the plasticizer is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0059] In some embodiments, when the additive includes a light stabilizer, the content of the plasticizer is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0060] In some embodiments, the defoamer is a silicone defoamer, such as BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, BYK-1760 produced by BYK, DC65, AFE-7820 produced by Dow Corning, or a mixture of these defoamers in any proportion.

[0061] In some embodiments, the leveling agent is a silicone surface additive, such as BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566 produced by BYK, or a mixture of these surface additives in any proportion.

[0062] In some embodiments, the plasticizer is toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate or a mixture of these compounds in any proportion.

[0063] In some embodiments, the dehydrating agent includes but is not limited to p-toluenesulfonyl isocyanate, triethyl orthoformate, CUWR-WB20 dehydrating agent of Guangzhou Yourun Synthetic Materials Co., Ltd., ALT-201 dehydrating agent of Anxiang Elite Chemical Co., Ltd., PCCI dehydrating agent of Shanghai Ruhr Chemical Trading Co., Ltd., etc.

[0064] In some embodiments, the ultraviolet absorber includes but is not limited to 2-hydroxy-4-n-octyloxybenzophenone, 2-(5-chloro-2H-benzotriazole-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol, N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-oxalamide, 2-(2H-benzotriazole-2-yl)-p-cresol, 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 2-(2H-benzotriazole-2)-4,6-di(1-methyl-1-phenylethyl)phenol or any mixture of these additives in any proportion.

[0065] In some embodiments, the light stabilizer includes, but is not limited to, light stabilizer 944, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, light stabilizer 622, or a mixture of these additives in any ratio.

[0066] In some embodiments, the antioxidant includes but is not limited to Irganox 1010, Irganox 168, Irganox 1076, Irganox 1098, Irganox MD1024, Irganox 1035, BASF liquid antioxidant 1135, Irganox B225, Irganox PS800 (DLTP), Irganox B900, Irganox 3114, Irganox 245, Irganox B215, Irganox PS-802FL, Irganox Borchors Ascinin@Special, Irganox Borchors Ascinin@P or any mixture of these additives.

[0067] See also Figure 1 , Figure 1 It is a flow chart of an embodiment of a substrate processing method of the present application, and the method comprises: step S101 to step S104.

[0068] Step S101: providing a substrate, wherein the substrate includes a glass substrate or a resin substrate.

[0069] Step S102: providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is any of the photopolymer holographic recording media described above.

[0070] Step S103: performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate.

[0071] Step S104: evenly distribute the mixed solution of the photopolymer holographic recording medium on the surface of the substrate (for example, by coating), and bake it, so that the compound having multiple isocyanate reactive functional groups and polyisocyanate compounds in the photopolymer holographic recording medium react to form a film-forming resin, and the hydroxyl groups on the surface of the substrate participate in the reaction to connect the film-forming resin to the substrate in a covalent bond manner.

[0072] In the embodiment of the present application, since the photopolymer holographic recording medium can react with the surface of the substrate having hydroxyl groups generated on the surface after treatment, the volume holographic grating prepared by the photopolymer can be effectively adhered to the substrate without affecting the holographic recording performance of the photopolymer.

[0073] The surface of the substrate is hydroxylated, including but not limited to dry hydroxylation and wet hydroxylation.

[0074] In some embodiments, step S103, performing hydroxylation on the surface of the substrate, includes: performing hydroxylation on the surface of the substrate by dry hydroxylation.

[0075] In some embodiments, step S103, the hydroxylation treatment of the surface of the substrate by dry hydroxylation includes: placing the substrate in a processing device, and performing plasma treatment on the surface of the substrate by a gas to generate hydroxyl groups on the surface of the substrate. The gas includes one or more of H2O, O2, H2O2, and air.

[0076] See also Figure 2 , Figure 2 It is a flow chart of another embodiment of the substrate processing method of the present application, characterized in that the method comprises: step S201 to step S205.

[0077] Step S201: providing a substrate, wherein the substrate comprises a glass substrate or a resin substrate.

[0078] Step S202: providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is any of the photopolymer holographic recording media described above.

[0079] Step S203: performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate.

[0080] Step S204: immersing the hydroxylated substrate in a silane coupling agent solution and allowing it to stand to generate polymerizable groups on the surface of the substrate. The polymerizable groups can react with polymerizable monomers in the photopolymer holographic recording medium to generate polymers.

[0081] Step S205: uniformly distributing the mixed solution of the photopolymer holographic recording medium on the surface of the substrate and baking the mixed solution to make the compound with multiple isocyanate reactive functional groups and the polyisocyanate compound in the photopolymer holographic recording medium react to form a film-forming resin, making the hydroxyl groups on the surface of the substrate participate in the reaction to connect the film-forming resin to the substrate in a covalent bond manner, and making the polymerizable groups on the surface of the substrate react with the polymerizable monomer to form a polymer that is covalently connected to the substrate.

[0082] In the embodiment of the present application, since the photopolymer holographic recording medium can react with the surface of the substrate having hydroxyl groups and polymerizable groups generated on the surface after treatment, the volume holographic grating prepared by the photopolymer can be effectively adhered to the substrate without affecting the holographic recording performance of the photopolymer.

[0083] In some embodiments, the silane coupling agent includes vinyl tris(2-methoxyethoxy)silane, vinyl trimethoxysilane, and 3-(trimethoxysilyl)propyl methacrylate.

[0084] In some embodiments, the solvent for preparing the silane coupling agent solution can be selected from petroleum ether, dichloromethane, chloroform, ethyl acetate, acetone, ethanol, benzene, toluene, xylene, chlorobenzene, N,N-dimethylformamide, and dimethyl sulfoxide.

[0085] The embodiments of the present application are described below through specific examples.

[0086] Embodiment 1: Six kinds of photopolymer holographic recording media 1-6 are provided. The preparation method of the photopolymer holographic recording media is to mix all components uniformly. The raw material components are shown in Table 1-Table 6.

[0087] Table 1

[0088]

[0089] Table 2

[0090]

[0091] Table 3

[0092]

[0093] Table 4

[0094]

[0095]

[0096] Table 5

[0097]

[0098] Table 6

[0099]

[0100] Example 2: A volume holographic grating 1-6 is prepared using a photopolymer holographic recording medium 1-6. The preparation method of the volume holographic grating includes: substrate processing, substrate coating, and light treatment. Please refer to Table 7 for details.

[0101] The steps of substrate treatment and substrate coating include: placing a glass substrate or a resin substrate in a processing device, and performing plasma treatment on the sample surface by gas to generate hydroxyl groups on the substrate surface. The gases used include but are not limited to H2O, O2, H2O2, air, etc., and a mixed gas of the above gases can also be used. Then, a photopolymer type holographic recording medium mixed liquid is quickly coated and sent to an oven for baking. The compound with a hydroxyl group in the mixed liquid reacts with the compound with an isocyanate group to form a film-forming resin, and the hydroxyl groups on the surface of the glass substrate or the resin substrate participate in the above reaction to connect the film-forming resin of the photopolymer layer to the glass substrate or the resin substrate in a covalent bond manner.

[0102] Table 7

[0103]

[0104] Example 3: Volume holographic gratings 7-12 are prepared using photopolymer holographic recording media 1-6. The preparation method of the volume holographic grating includes: substrate processing, substrate coating, and light treatment. Please refer to Table 8 for details.

[0105] The steps of substrate treatment and substrate coating include: placing a glass substrate or a resin substrate in a processing device, and plasma treating the sample surface with a gas to generate hydroxyl groups on the substrate surface. The gases used include but are not limited to H2O, O2, H2O2, air, etc., and a mixed gas of the above gases can also be used. The above-mentioned hydroxylated glass substrate or resin substrate is immersed in a prepared silane coupling agent solution and allowed to stand. By controlling the standing time, the ratio of hydroxyl groups and polymerizable groups (acrylate, methacrylate, allyl ether) on the substrate surface can be regulated. After standing, the substrate surface is rinsed with ethanol and dried with nitrogen, and then the above-mentioned photopolymer holographic recording medium mixed liquid is quickly coated and sent to an oven for baking. The compound with hydroxyl groups in the mixed liquid reacts with the compound with isocyanate groups to form a film-forming resin. At the same time, the hydroxyl groups on the surface of the glass substrate or the resin substrate will participate in the above reaction, thereby connecting the film-forming resin of the photopolymer layer to the glass substrate or the resin substrate in a covalent bond manner. In addition, during the holographic recording process, the polymerizable group can also react with the writing monomer component to connect the polymer generated by the reaction to the glass substrate or the resin substrate in the form of a covalent bond.

[0106] Table 8

[0107]

[0108] Comparative Example:

[0109] Volume holographic grating comparative examples 1-6 were prepared using photopolymer holographic recording media 1-6. The preparation method of the volume holographic grating included: substrate coating and light treatment. For details, see Table 9.

[0110] The step of coating the substrate includes: coating the surface of the glass substrate or the resin substrate with a mixed solution of photopolymer holographic recording medium, and then putting the mixed solution into an oven for baking.

[0111] Table 9

[0112]

[0113] Test example:

[0114] The properties of holographic recording media 1 to 6 in Example 1 were tested, and the results are shown in Table 10. The adhesion between volume holographic gratings 1 to 12, comparative examples 1 to 6 and a glass substrate or a resin substrate was tested, and the results are shown in Table 10. Figure 3-Figure 6 , as shown in Table 11. Figure 3 and Figure 4 They are the hundred-grid test result diagrams of volume holographic grating 1 and volume holographic grating 10 respectively; Figure 5 and Figure 6 They are the hundred-grid test result diagrams of comparative examples 3 and 6 respectively; combined with Table 11, Figure 3 and Figure 4 It can be seen that the edge of the scribe line is smooth, and there is no paint film falling off at the edge and intersection of the scribe line. The level of adhesion between the volume holographic grating and the substrate is 5B. Figure 5 and Figure 6 It can be seen that there are pieces of paint film falling off at the edges and intersections of the scribe lines, and the total falling area is between 15% and 35%. The level of adhesion between the volume holographic grating and the substrate is 2B.

[0115] (1) The method for testing the performance of the holographic recording medium comprises the following steps:

[0116] Solid-state lasers with wavelengths of 405nm, 532nm, and 633nm were used as light sources. After passing through a beam expander, beam splitter, and half-wave plate, two beams with the same light intensity and a diameter of 8mm were obtained. The two beams intersected in the prepared holographic recording medium for exposure, and the light intensity was 2.91mW / cm 2 The detection light source is a 785nm wavelength solid laser that does not react with the recording medium. The detection light is incident on the exposure area from the Bragg angle. The transmitted light and diffracted light are monitored in real time by the photodetector. The single grating diffraction efficiency (η) of the photopolymer sample and the photosensitivity (S) of the recording medium are calculated by formulas (1) to (3).

[0117]

[0118] Where η is the diffraction efficiency, η max is the highest diffraction efficiency, I d is the diffracted light, I t is the transmitted light, S is the photosensitivity, E is the exposure energy, and ΔE is the exposure energy when the highest diffraction efficiency is achieved.

[0119] (2) A hundred-grid test is used to test the adhesion between the volume holographic grating and the glass substrate or the resin substrate.

[0120] The 100-grid test is the most common method for testing the adhesion of paint films. According to international standards, it can be divided into 6 levels, with units of 0B, 1B, 2B, 3B, 4B, and 5B. The higher the level, the stricter the requirements. Level 5B means that the edge of the line is smooth, and there is no paint film falling off at the edge and intersection of the line. Level 4B means that there are small pieces of paint film falling off at the intersection of the line, and the total falling area is less than 5%. Level 3B means that there are small pieces of paint film falling off at the edge and intersection of the line, and the total falling area is between 5% and 15%. Level 2B means that there are pieces of paint film falling off at the edge and intersection of the line, and the total falling area is between 15% and 35%. Level 1B means that there are pieces of paint film falling off at the edge and intersection of the line, and the total falling area is between 35% and 65%. Level 0B means that the falling area exceeds the 1B standard.

[0121] The Baige test method includes the following steps:

[0122] Use a grid cutter to cut a cross grid pattern on the coating, with the cut reaching the substrate; use a brush to brush five times in each diagonal direction, stick tape on the cut and then pull it apart (it is specified to use 3M600 or 610 tape to stick in the grid and quickly pull up the 3M tape); observe the situation of the grid area, and use a magnifying glass to observe the amount of tape stuck.

[0123] Table 10

[0124]

[0125] Table 11

[0126] Volume holographic grating Adhesion Volume holographic grating 1 5B Volume holographic grating 2 5B Volume holographic grating 3 5B Volume holographic grating 4 5B Volume holographic grating 5 5B Volume holographic grating 6 5B Volume holographic grating 7 5B Volume holographic grating 8 5B Volume holographic grating 9 5B Volume holographic grating 10 5B Volume holographic grating 11 5B Volume holographic grating 12 5B Comparative Example 1 2B Comparative Example 2 1B Comparative Example 3 2B Comparative Example 4 2B Comparative Example 5 1B Comparative Example 6 2B

[0127] The photopolymer holographic recording medium provided in the embodiment of the present application has high sensitivity and can record a transmissive / reflective volume holographic grating with high diffraction efficiency. Specifically, the sensitivity of the holographic recording medium is greater than 85 cm / mJ, and the exposure amount is less than 12 mJ / cm 2 , the diffraction efficiency of the recording grating is greater than 95%. After the substrate is processed by the method provided in the embodiment of the present application, the volume holographic grating can be effectively adhered to the glass substrate or the resin substrate, and has no effect on the holographic recording performance of the photopolymer.

[0128] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0129] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0130] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A photopolymer holographic recording medium, characterized in that: The photopolymer holographic recording medium includes a compound having a plurality of isocyanate-reactive functional groups, a polyisocyanate-based compound, a polymerizable monomer, a photosensitive initiation system, a chain transfer agent, a catalyst, and additives.

2. The photopolymer holographic recording medium according to claim 1, wherein: The mass ratio of the compound having multiple isocyanate reactive functional groups, the polyisocyanate compound, the polymerizable monomer, the photosensitive initiation system, the chain transfer agent, the catalyst and the additive is 10-70:10-50:0.1-60:0.1-4:0.1-3:0.1-3:0.1-10.

3. The photopolymer holographic recording medium according to claim 1, wherein: The photosensitive initiation system comprises a photosensitizer and a photoinitiator, and the mass ratio of the photosensitizer to the photoinitiator is 0.001-1:0.1-3.

4. The photopolymer holographic recording medium according to claim 1, wherein: The isocyanate reactive functional group is a hydroxyl group; the compound having multiple isocyanate reactive functional groups includes a compound having a refractive index less than or equal to 1.55 and having two or more hydroxyl functional groups.

5. The photopolymer holographic recording medium according to claim 4, characterized in that: The compound having multiple isocyanate reactive functional groups includes: tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200 to 2000, polycarbonate polyol, and polyether polyol.

6. The photopolymer holographic recording medium according to claim 1, wherein: The polyisocyanate-based compound includes a compound having a refractive index less than or equal to 1.55 and having two or more isocyanate groups.

7. The photopolymer holographic recording medium according to claim 6, wherein: The polyisocyanate-based compounds include hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

8. The photopolymer holographic recording medium according to claim 1, wherein: The polymerizable monomer is selected from at least one of alkenyl naphthalene compounds, alkenyl anthracene compounds, alkenyl benzene compounds, acrylic compounds, methacrylic compounds, acrylate compounds, methacrylate compounds, N-vinyl pyrrole, N-vinyl carbazole, N-vinylimidazole, N-vinyl indole, N-vinyl pyrrolidone, and trans-N-3-ynyl butenyl carbazole.

9. A substrate processing method, characterized in that: The method comprises: Providing a substrate, wherein the substrate comprises a glass substrate or a resin substrate; Providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is the photopolymer holographic recording medium according to any one of claims 1 to 8; Performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate; The mixed solution of the photopolymer holographic recording medium is evenly distributed on the surface of the substrate and baked, so that the compound having multiple isocyanate reactive functional groups and the polyisocyanate compound in the photopolymer holographic recording medium react to form a film-forming resin, and the hydroxyl groups on the surface of the substrate participate in the reaction to connect the film-forming resin to the substrate in a covalent bond manner.

10. The method according to claim 9, characterized in that The hydroxylation treatment of the surface of the substrate comprises: The surface of the substrate is hydroxylated by dry hydroxylation.

11. The method according to claim 10, characterized in that The method of performing a hydroxylation treatment on the surface of the substrate by dry hydroxylation comprises: The substrate is placed in a processing device, and a surface of the substrate is subjected to plasma treatment by a gas, so that hydroxyl groups are generated on the surface of the substrate. The gas includes one or more of H2O, O2, H2O2, and air.

12. A substrate processing method, characterized in that: The method comprises: Providing a substrate, wherein the substrate comprises a glass substrate or a resin substrate; Providing a mixed solution of a photopolymer holographic recording medium, wherein the photopolymer holographic recording medium is the photopolymer holographic recording medium according to any one of claims 1 to 8; Performing a hydroxylation treatment on the surface of the substrate to generate hydroxyl groups on the surface of the substrate; Immersing the hydroxylated substrate in a silane coupling agent solution and allowing it to stand to generate polymerizable groups on the surface of the substrate, wherein the polymerizable groups can react with polymerizable monomers in the photopolymer holographic recording medium to generate polymers; The mixed solution of the photopolymer holographic recording medium is uniformly distributed on the surface of the substrate and baked to make the compound with multiple isocyanate reactive functional groups and the polyisocyanate compound in the photopolymer holographic recording medium react to form a film-forming resin, the hydroxyl groups on the surface of the substrate participate in the reaction to connect the film-forming resin to the substrate in a covalent bond manner, and the polymerizable groups on the surface of the substrate react with the polymerizable monomer to form a polymer that is covalently connected to the substrate.

13. The method according to claim 12, characterized in that The silane coupling agent includes vinyl tris(2-methoxyethoxy)silane, vinyl trimethoxysilane, and 3-(trimethoxysilyl)propyl methacrylate.

14. The method according to claim 12, characterized in that The solvent for preparing the silane coupling agent solution can be selected from petroleum ether, dichloromethane, chloroform, ethyl acetate, acetone, ethanol, benzene, toluene, xylene, chlorobenzene, N,N-dimethylformamide, and dimethyl sulfoxide.

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