Red light photosensitive initiation system and application thereof

Abstract

The invention relates to the technical field of holographic optics, in particular to a red light photosensitive initiation system and application thereof. The red light photosensitive initiation system comprises the following components: a first component: squarylium cyanine dye; the second component is an electron acceptor which is selected from at least one of diaryl iodonium salt, aryl sulfonium salt and triazine compounds; and the third component is an electron donor which is borate and is selected from at least one of alkyl aryl borate and aryl borate. The red light photosensitive initiation system can rapidly generate active free radicals or anions / cations under illumination in the wavelength range of 600-750 nm to initiate monomer polymerization. The invention also provides application of the red light photosensitive initiation system in photocuring and preparation of a red-sensitive photopolymer type holographic recording medium, and preparation of a red light photopolymer with high diffraction efficiency and high photosensitivity can be realized.

Description

Technical Field

[0001] This invention relates to the field of holographic optics, and in particular to a red light photosensitive initiation system and its application. Background Technology

[0002] With the development of technology, Heads-Up Display (HUD) technology has been widely used in various fields such as automotive, medical, military, and industrial production. In the automotive industry, HUD technology has significantly improved driving safety and intelligent experience. It can project key data such as speed, navigation, and driver assistance information onto the windshield in front of the driver's field of vision, allowing the driver to observe road conditions without having to look down at the instrument panel, thereby improving driving safety.

[0003] To provide richer information, achieve better interactivity, and be applicable to a wider range of scenarios, the upgrade from monochrome to full-color display is an inevitable trend in HUD development. This requires the optical system in the HUD to have high optical transmission efficiency for red, green, and blue light. The optical scheme is a key factor determining the performance and cost of the HUD. Among existing optical schemes, the optical waveguide of a volume holographic grating (VHG) is recognized as the best solution. Photopolymers are the preferred holographic recording medium for fabricating high-performance VHGs. To achieve maximum diffraction efficiency for red, green, and blue light, VHGs need to be fabricated separately using red, green, and blue lasers. Under coherent laser exposure, the photopolymer can polymerize in the bright areas of the coherent light, creating a refractive index difference with the dark areas of the coherent light, thus forming a refractive index modulation grating. It is required that the photopolymer can rapidly initiate monomer polymerization under laser irradiation in the corresponding three wavelength ranges to achieve the fabrication of the refractive index modulation grating. Currently, there is a lot of research on photopolymers that are sensitive to blue and green light, but there is less research on photopolymers that are sensitive to red light, and their photosensitivity is also relatively low, which greatly restricts the development of full-color VHG and optical waveguides.

[0004] In 2013, Covestro disclosed a patent CN201180053775.X, which described a low-absorption photosensitive dye / alkylarylborate initiation system and the preparation of a red-sensitive holographic recording medium. In 2021, Bruder et al. (Digital Optical Technologies 2021. SPIE, 117880B (20 June 2021)) obtained a near-infrared holographic recording medium using a heptamethine cyanine dye / iodonium salt / alkylarylborate system as the photoinitiation system, which can be used to prepare HUDs. In the same year, Tomita et al. discovered a photosensitive initiation system and prepared a 640 nm red-light holographic recording medium, but both showed low photosensitivity.

[0005] In summary, to achieve full-color display in a HUD, this invention provides a red-light photosensitive initiation system. This system can be used to fabricate red-sensitive holographic recording media, which has high photosensitivity and can be used to prepare VHGs with high diffraction efficiency and high refractive index modulation. When combined with mature blue and green sensitive systems, it holds promise for fabricating various types of full-color HUDs. Summary of the Invention

[0006] Existing photoluminescent polymers using red-light photoinitiating systems generally suffer from low diffraction efficiency and low photosensitivity, failing to meet the application requirements of HUDs. To address these shortcomings of existing red-light photoinitiating systems for photoluminescent polymers, this invention proposes a red-light photoinitiating system that can rapidly generate active free radicals or anions / cations under illumination in the 600-750 nm wavelength range, initiating monomer polymerization. This invention also provides the application of the aforementioned red-light photoinitiating system in photocuring and the preparation of red-sensitive photopolymer-type holographic recording media, enabling the preparation of red-light photopolymers with high diffraction efficiency and high photosensitivity.

[0007] The present invention adopts the following technical solution:

[0008] A red light photosensitizing initiation system comprises the following components:

[0009] Component 1: Qualcourcyanin dye;

[0010] Second component: Electron acceptor, selected from at least one of diaryliodonium salts, arylthiodonium salts, and triazine compounds; structural formula as follows:

[0011] The third component is an electron donor, which is a borate selected from at least one of alkylarylborates and arylborates.

[0012] Furthermore, the squaricine dye has at least one of the general chemical formulas Dye-1 or Dye-2:

[0013]

[0014] Among them, R1 and R2 can each be one of the following structures:

[0015]

[0016] Among them, X1, X2, X3, and X4 each independently represent hydrogen, halogen, nitro, amino, alkyl, and C1~C4. 10 Any one of alkoxy, alkylamino, and aryl groups;

[0017] X5, X6, and X7 each independently represent hydrogen, hydroxyl, nitro, halogen, aryl, alkyl, and C1~C6 groups. 10 Alkoxy, alkylamino, , , Any one of them; X8 represents hydrogen, C1~C 10 Any one of the alkyl groups.

[0018] Furthermore, the halogen is selected from F, Cl, Br, and I; the alkyl and alkylamino groups have 1-10 carbon atoms, preferably 1-4 carbon atoms; the aryl group has 6-20 carbon atoms, preferably 6-15 carbon atoms. For example, the alkyl group is selected from methyl, ethyl, propyl, and butyl; the alkoxy group is selected from methoxy, ethoxy, propoxy, and butoxy; and the aryl group is selected from phenyl, biphenyl, and naphthyl.

[0019] It should be noted that in the dyes expressed by the above-mentioned general structural formulas of Dye-1, the cation exists in a delocalized manner, and multiple tautomer structures exist. In the embodiments of this application, when at least one tautomer structure of certain dyes is applicable to each general structural formula, a certain dye is set as a dye represented by each general structural formula. In the embodiments of this application, for dyes represented by general structural formulas, any tautomer structure can be used as long as at least one of its tautomer structures is applicable to the general structural formula. For example, the following dyes have three expression forms: I, II, and III, all of which represent the same dye. In the embodiments of this application, any one of the expression forms I, II, and III can be exemplarily shown to represent the type of dye contained in the red light photoinitiating system protected in the embodiments of this application.

[0020]

[0021] Furthermore, the second component is an electron acceptor, specifically selected from at least one of diaryliodonium salts, arylthiodonium salts, or triazine compounds, with the following chemical structures:

[0022]

[0023] Among them, R3 and R4 independently represent hydrogen, hydroxyl, nitro, halogen, aryl, and C1~C. 10 Alkyl, C1~C 10 Alkoxy, C1~C 10 Any of the alkylamino groups; Anion - Represents the halogen anion (F - Cl - ,Br - I - ), hexafluorophosphate anion, tetrafluoroborate anion, , , , Any one of them; Y1 represents C1~C 10Alkyl, C1~C 10 Alkoxy, C1~C 10 Any of the alkylamino groups; Y2 represents hydrogen, hydroxyl, nitro, halogen, aryl, C1~C 10 Alkyl, C1~C 10 Alkoxy, C1~C 10 Any one of the alkylamino groups;

[0024] R5 represents C1~C 10 Alkyl, C3~C 10 alkenyl, C5-C7 cycloalkyl, C6-C alkyl substituted with at least one specific group 10 Any one of the aryl groups; wherein a specific group is selected from halogen, C1-C4 alkyl, trifluoromethyl, C1-C4 alkoxy, trifluoromethoxy, aryl, or phenoxy; R6, R7, and R8 each independently represent a halogen, C1-C4 alkyl, trifluoromethyl, C1-C4 alkoxy, trifluoromethoxy, aryl, or phenoxy groups. 10 Alkyl, C1~C 10 Any one of the haloalkyl groups.

[0025] The third component is an electron donor, an alkylarylborate or arylborate, with the following chemical structure:

[0026]

[0027] Among them, R9, R 10 R 11 Each independent representative is a C6-C group substituted with at least one of the following groups. 10 Aryl: halogen, C1~C4 alkyl, trifluoromethyl, C1~C4 alkoxy, trifluoromethoxy, aryl or phenoxy;

[0028] R 12 Representing C1~C 10 Alkyl, C3~C 10 alkenyl, C5-C7 cycloalkyl, C6-C alkyl substituted with at least one specific group 10 Any one of the aryl groups; wherein the specific group can be: halogen, C1~C4 alkyl, trifluoromethyl, C1~C4 alkoxy, trifluoromethoxy, aryl or phenoxy;

[0029] Cation + Representing sodium ions and potassium ions. Any one of them; where Z1, Z2, Z3, and Z4 independently represent hydrogen, C1~C1, C2~C3, C4, and C4, respectively. 10 Any one of alkyl or aryl.

[0030] Furthermore, the selected red-sensitive dye Dye-1 is chosen from one of the following structures:

[0031]

[0032] Furthermore, the selected red-sensitive dye Dye-2 is chosen from one of the following structures:

[0033]

[0034] Furthermore, the selected diaryliodonium salt is chosen from one of the following structures:

[0035]

[0036] Furthermore, the selected arylthionium salt is chosen from one of the following structures:

[0037]

[0038] Furthermore, the selected triazine compounds are chosen from one of the following structures:

[0039]

[0040] Furthermore, the selected alkylarylborates and arylborates are selected from one of the following structures:

[0041]

[0042] Furthermore, the mass ratio of the first component, the second component, and the third component in the red light photosensitive initiation system is 1:3 to 100:3 to 100. For example, the mass ratio of the first component, the second component, and the third component in the red light photosensitive initiation system can be 1:3:3, 1:4:4, 1:5:5, 1:6:6, 1:7:7, 1:8:8, 1:9:9, 1:10:10, 1:20:20, 1:30:30, 1:40:40, 1:50:50, 1:60:60, 1:70:70, 1:80:80, 1:90:90, or 1:100:100.

[0043] Furthermore, the initiation light source used in the red light photosensitive initiation system is a visible light source with a wavelength range of 600~750 nm, including but not limited to LEDs, lasers and other light sources with a wavelength range of 600~750 nm.

[0044] The present invention also provides an application of the above-mentioned red light photoinitiator system in photocuring, specifically: a prepolymer liquid composed of the red light photoinitiator system and polymerizable monomers as described above is added to a mold and irradiated with a visible light source in the wavelength range of 600~750 nm to obtain the product.

[0045] Furthermore, the mass ratio of the red light photoinitiator system to the polymerizable monomer in the prepolymer solution is 1:20~200; for example, the mass ratio of the red light photoinitiator system to the polymerizable monomer in the prepolymer solution can be 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, 1:190, 1:200, etc.

[0046] Furthermore, the polymerizable monomer is selected from at least one of alkenylnaphthalene compounds, alkenylanthracene compounds, alkenylbenzene compounds, acrylic acid compounds, methacrylic acid compounds, acrylate compounds, methacrylate compounds, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazol, N-vinylindole, N-vinylpyrrolidone, and trans-N-3-yntynebutenylcarbazole.

[0047] For example, the alkenylbenzene compound may be selected from styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene, etc.

[0048] For example, the methacrylic acid compound may be methacrylic acid and its derivatives; for example, the acrylate compound may 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-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate, etc.

[0049] For example, the methacrylate compound may 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-bis(2-thionaphthyl)2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate, etc.

[0050] For example, the alkenyl anthracene compound may be selected from 2-vinylanthracene, 9-vinylanthracene, etc.

[0051] For example, the alkenylnaphthalene compound may be selected from 1-vinylnaphthalene, 2-vinylnaphthalene, etc.

[0052] The present invention also provides an application of the red light photosensitive initiation system described above in the preparation of red-sensitive photopolymer holographic recording media.

[0053] Furthermore, the red-sensitive photopolymer holographic recording medium comprises the following raw materials:

[0054] Component a) A compound having multiple isocyanate reactive functional groups;

[0055] Component b) Polyisocyanate group compounds;

[0056] Component c) Polymerizable monomers;

[0057] Component d) Red light photosensitizing initiation system;

[0058] Component e) Chain transfer agent;

[0059] Component f) Catalyst;

[0060] Component g) Additives;

[0061] The mass ratio of components a), b), c), d), e), f), and g) is 10~70:10~50:10~60:0.1~5:0.1~3:0.1~3:0.1~7. For example, the mass ratio of components a), b), c), d), e), f), and g) can be 20:20:50:3:2:2:3, 15:25:50:3:2:2:3, or 25:15:50:3:2:2:3.

[0062] Among them, component d) is the red light photosensitive initiation system as described above, accounting for 0.01~5 wt% of the photopolymer holographic recording medium.

[0063] It should be noted that photopolymer-type holographic recording media materials typically contain a base resin with a low refractive index and a writing monomer with a high refractive index. In this invention, components a) and b) can react to form a base resin with a low refractive index, and component c) is equivalent to a writing monomer with a high refractive index.

[0064] Furthermore, in the compound having multiple isocyanate reactive functional groups, the isocyanate reactive functional group is a hydroxyl group; preferably, it is a compound with a low refractive index and having two or more hydroxyl functional groups, which can be, for example, tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyols with a molecular weight of 200 to 2000, polycarbonate polyols, polyether polyols, etc.

[0065] Furthermore, the polyisocyanate compound is a low-refractive-index compound with two or more isocyanate groups. For example, it can be hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tri(hexamethylene)isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc.

[0066] Furthermore, the polymerizable monomer is selected from at least one of alkenylnaphthalene compounds, alkenylanthracene compounds, alkenylbenzene compounds, acrylic acid compounds, methacrylic acid compounds, acrylate compounds, methacrylate compounds, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazol, N-vinylindole, N-vinylpyrrolidone, and trans-N-3-yntynebutenylcarbazole.

[0067] For example, the alkenylbenzene compound may be selected from styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene, etc.

[0068] For example, the methacrylic acid compound may be methacrylic acid and its derivatives; for example, the acrylate compound may 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-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate, etc.

[0069] For example, the methacrylate compound may 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-bis(2-thionaphthyl)2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate, etc.

[0070] For example, the alkenyl anthracene compound may be selected from 2-vinylanthracene, 9-vinylanthracene, etc.

[0071] For example, the alkenylnaphthalene compound may be selected from 1-vinylnaphthalene, 2-vinylnaphthalene, etc.

[0072] Furthermore, the chain transfer agent is a thiol compound, including but not limited to one or more of dodecyl mercaptan, mercaptoethanol, hexamethylene mercaptan, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, and 4-methyl-4H-1,2,4-triazole-3-thiol.

[0073] Furthermore, the catalyst is a tertiary amine catalyst or an organometallic catalyst, including but not limited to triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts.

[0074] Furthermore, the additives include one or more of defoamers, leveling agents, plasticizers, and dehydrating agents.

[0075] For example, the defoamer is an organosilicone defoamer, such as BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, BYK-1760 manufactured by BYK Corporation, DC65, AFE-7820 manufactured by Dow Corning Corporation, or any mixture of these defoamers in any proportion.

[0076] For example, 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, or any mixture of these surface additives manufactured by BYK Corporation.

[0077] For example, the plasticizer is toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalates, or any mixture of these compounds in any proportion.

[0078] For example, the dehydrating agents include, but are not limited to, p-toluenesulfonyl isocyanate, triethyl orthoformate, CUWR-WB20 dehydrating agent from Guangzhou Yourun Synthetic Materials Co., Ltd., ALT-201 dehydrating agent from Anxiang Elite Chemical Co., Ltd., and PCCI dehydrating agent from Shanghai Luer Chemical Trading Co., Ltd.

[0079] The beneficial effects of this invention are as follows:

[0080] This invention provides a red light photosensitive initiation system. The system comprises electron acceptors such as squaric acid cyanine dyes, diaryliodonium salts, arylthiodonium salts, or triazine compounds, and electron donors such as alkylarylborates or arylborates. This system can be matched with LED or laser light sources with wavelengths of 600-750 nm, absorbing light energy and rapidly generating initiating free radicals, anions, or cations to induce polymerization, achieving a highly efficient photocuring process under red light. For photopolymerization reactions of different monomers, the monomer conversion rate reaches over 85%.

[0081] The red-light photosensitive initiation system provided by this invention can be widely applied in coatings, adhesives, photoresists, electronic packaging, dental restorations, 3D printing, photopolymers, holographic polymers, holographic polymer-dispersed liquid crystals, nanoparticle-doped photopolymers, two-photon polymerization, biological scaffolds, micro / nano fabrication, and three-dimensional optical storage. Using the red-light photosensitive initiation system of this invention in the preparation of red-sensitive photopolymer holographic recording media can significantly improve the photosensitivity of the photopolymer, enabling the recording of high-diffraction-efficiency transmission / reflection volume holographic gratings. The grating diffraction efficiency can reach 93%, while the sensitivity is also significantly improved, far exceeding that of known red-light photosensitive initiation systems in the prior art, and basically meeting the requirements for HUD optical waveguides. This may be attributed to the selection of specific azircinyl dyes, specific electron acceptors, and electron donors. Attached Figure Description

[0082] Figure 1 The photopolymerization kinetics curves of 2-phenoxyethyl methacrylate monomer initiated by red light photosensitive initiation systems composed of different dyes, electron donors, and electron acceptors under irradiation by light sources of different wavelengths are shown in Table 1 (photopolymerization kinetic curves of samples 1, 3, 9, and 13).

[0083] Figure 2 This is a schematic diagram of the optical path for transmission and reflection grating exposure.

[0084] Figure 3 The diffraction efficiency growth curves of the photopolymer samples recorded in Examples 2, 3, 4 and Comparative Examples 1, 2, 3 are shown.

[0085] Figure 4 The angle selection curve and fitting data curve of the reflective grating recorded on the photopolymer sample in Example 2 are shown. Detailed Implementation

[0086] To illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and accompanying drawings.

[0087] Example 1

[0088] Weigh 2-phenoxyethyl methacrylate monomer (POEA), and add 0.1 wt% dye, 1 wt% electron donor, and 1 wt% electron acceptor. The structural formulas of the dye, electron donor, and electron acceptor are shown in Table 1. Stir to thoroughly mix the four components into a homogeneous prepolymer solution, pour it into a 0.5 mm thick hollow glass mold, and use a real-time infrared spectrometer (experimental temperature 25 ℃) to test the prepolymer solution under a light source (10 mW / cm²). 2 The photopolymerization kinetics curves of prepolymers for samples 1, 3, 9, and 13 are shown below. Figure 1As shown in Table 1, the relevant data are summarized. The experimental results show that different red light photosensitive initiation systems can efficiently initiate the polymerization of monomer POEA under light irradiation. Among them, the red light photosensitive initiation system shown in sample 9 has the highest monomer polymerization initiation efficiency.

[0089] Table 1. Structural formulas and photopolymerization properties of dyes, electron donors, and electron acceptors.

[0090]

[0091] Examples 2 to 4 provide three photopolymer-type holographic recording media, the raw material components of which are detailed in Tables 2 to 4.

[0092] Example 2

[0093] The preparation of red-sensitive photopolymer holographic recording media includes the following steps:

[0094] Under red light conditions, the raw material components listed in Table 2 are added sequentially to a 500 mL container equipped with a stirrer. The mixture is stirred thoroughly at room temperature for 15 minutes. Dust and other impurities are removed by passing the mixture through a 0.45-micron filter to obtain a mixture. The mixture is then injected into 80 mm × 35 mm × 0.03 mm and 80 mm × 35 mm × 0.02 mm glass containers. After curing at room temperature, the holographic recording medium can be obtained.

[0095] Table 2 Components of raw materials for holographic recording media

[0096]

[0097] Example 3

[0098] The red-sensitive photopolymer holographic recording medium was prepared according to the preparation method of Example 2. The difference between the medium and Example 2 is that its raw material components are shown in Table 3.

[0099] Table 3 Components of raw materials for holographic recording media

[0100]

[0101] Example 4

[0102] The red-sensitive photopolymer holographic recording medium was prepared according to the preparation method of Example 2. The difference between Example 2 and the original material components is shown in Table 4.

[0103] Table 4. Components of raw materials for holographic recording media

[0104]

[0105] Comparative Example 1

[0106] A red-sensitive photopolymer-type holographic recording medium was prepared according to the preparation method of Example 2, except that its raw material components are shown in Table 5. After the holographic recording medium was prepared, holographic recording was performed using a 633 nm laser with a recording intensity of 4 mW / cm². 2 Photopolymer samples were recorded with transmissive (1570 lines / mm) and reflective (4800 lines / mm) gratings.

[0107] Table 5. Raw material composition of holographic recording media

[0108]

[0109] Comparative Example 2

[0110] A red-sensitive photopolymer-type holographic recording medium was prepared according to the preparation method of Example 2, except that its raw material components are shown in Table 6. After the holographic recording medium was prepared, holographic recording was performed using a 633 nm laser with a recording intensity of 4 mW / cm². 2 Photopolymer samples were recorded with transmissive (1570 lines / mm) and reflective (4800 lines / mm) gratings.

[0111] Table 6 Components of raw materials for holographic recording media

[0112]

[0113] Comparative Example 3

[0114] A red-sensitive photopolymer-type holographic recording medium was prepared according to the preparation method of Example 2, except that its raw material components are shown in Table 7. After the holographic recording medium was prepared, holographic recording was performed using a 633 nm laser with a recording intensity of 4 mW / cm². 2 Photopolymer samples were recorded with transmissive (1570 lines / mm) and reflective (4800 lines / mm) gratings.

[0115] Table 7 Components of raw materials for holographic recording media

[0116]

[0117] Application Example 1 (Raster Exposure)

[0118] Solid-state lasers with wavelengths of 633 nm, 760 nm, and 640 nm were used as light sources. After passing through a beam expander, beam splitter, and half-wave plate, two beams with the same intensity and a diameter of 10 mm were obtained. The two beams were then exposed within the prepared holographic recording medium.

[0119] Example 2 uses a 633 nm laser for holographic recording, with a recording light intensity of 3.5 mW / cm². 2 The diffraction efficiency of transmission (1570 lines / mm) and reflection (4800 lines / mm) gratings was recorded on photopolymer samples.

[0120] Example 3 uses a 760 nm laser for holographic recording, with a recording light intensity of 4 mW / cm². 2 The diffraction efficiency of transmission (1310 lines / mm) and reflection (4000 lines / mm) gratings was recorded on photopolymer samples.

[0121] Example 4 uses a 640 nm laser for holographic recording, with a recording light intensity of 4.5 mW / cm². 2 The diffraction efficiency of transmission (1560 lines / mm) and reflection (4750 lines / mm) gratings was recorded on photopolymer samples.

[0122] Optical schemes for recording transmission gratings and reflection gratings, such as Figure 2 As shown, the diffraction efficiency curves of the transmission gratings in Examples 2, 3, 4 and Comparative Example 1 are as follows: Figure 3 As shown.

[0123] Application Example 2 (Grating Holographic Performance Test)

[0124] During grating exposure, a beam of light is closed for 0.2 s every 2 s using a shutter. The transmitted and diffracted light of a single beam is monitored in real time using a photodetector. The single grating diffraction efficiency (η) of the photopolymer sample and the photosensitivity (S) of the recording medium are calculated using formulas (1) and (2).

[0125] (1)

[0126] (2)

[0127] In the formula, η is the diffraction efficiency of the recording grating, in %. d The intensity of the diffracted light is expressed in mW / cm². 2 I t Transmitted light intensity, unit mW / cm 2 η max To record the maximum diffraction efficiency of the grating (in %), d is the sample thickness (in cm), and ΔE is the exposure energy required to achieve the highest diffraction efficiency (in mJ / cm²). 2 S represents sensitivity, measured in cm / mJ.

[0128] The results are summarized in Table 8. Compared with Comparative Examples 1 to 3, the diffraction efficiency of the reflective and transmissive gratings in Examples 2, 3, and 4 was greatly improved, and the sensitivity was also increased several times. Among them, Example 2 achieved the best effect, with a grating diffraction efficiency of about 90%, which meets the requirements for HUD optical waveguides. The main difference between Comparative Example 1 and Example 2 is that in component d), Comparative Example 1 uses a photoinitiator instead of the electron donor and electron acceptor complex; the main difference between Comparative Example 2 and Example 2 is that in component d), cyanine dye is used instead of squaric acid cyanine dye; the main difference between Comparative Example 3 and Example 2 is that in component d), heptamethrin cyanine dye is used instead of squaric acid cyanine dye.

[0129] Table 8 Holographic Performance Parameters

[0130]

[0131] Application Example 3 (Testing and Fitting the Choice Angle)

[0132] The selection angle of the reflective grating in Example 2 was tested and fitted. The sample of Example 2 with the reflective grating was fixed on a rotating stage. A 635 nm laser was used for detection. The transmitted light was monitored in real time by a photodetector. The changes in the transmitted light intensity in the grating area and the non-grating area with the angle of the sample were recorded respectively. The angle selection curve of the grating was obtained by Equation (3).

[0133] (3)

[0134] In the formula, Δφ is the angular deviation of the detected laser relative to the Bragg angle, in degrees. g The transmitted light intensity in the grating region is expressed in mW / cm². 2 I n The intensity of transmitted light in the non-grating region is expressed in mW / cm². 2 .

[0135] The measured data were fitted using Kogelnik coupled-wave theory, and the results are as follows: Figure 4 As shown.

Claims

1. A red photoinitiating system, characterized in that, Comprise the following components: The first component: squarylium dye; The second component: electron acceptor, selected from at least one of diaryliodonium salt, arylsulfonium salt, triazine compound; The third component: electron donor, is borate, selected from at least one of alkyl aryl borate and aryl borate.

2. The red photoinitiating system according to claim 1, characterized in that, Squarylium dye, chemical structure general formula is at least one of Dye-1 or Dye-2: ； Further, halogen is selected from F, Cl, Br, I; alkyl, alkylamino has 1-10 carbon atoms, preferably has 1-4 carbon atoms; aryl has 6-20 carbon atoms, preferably has 6-15 carbon atoms. Such as alkyl is selected from methyl, ethyl, propyl, butyl; alkoxy is selected from methoxy, ethoxy, propoxy, butoxy; aryl is selected from phenyl, biphenyl, naphthyl. ； wherein X1, X2, X3, X4each independently represents any one of hydrogen, halogen, nitro, amino, alkyl, C1-C4 10 alkoxy, alkylamino, aryl; X5, X6, and X7 each independently represent hydrogen, hydroxyl, nitro, halogen, aryl, alkyl, and C1~C6 groups. 10 Alkoxy, alkylamino, , , Any one of them; X8 represents hydrogen, C1~C 10 Any one of the alkyl groups; Diaryliodonium salt, arylsulfonium salt, triazine compound chemical structure is as follows:

3. The red photoinitiating system according to claim 1, characterized in that, Alkyl aryl borate or aryl borate, chemical structure is: ； Among them, R3 and R4 independently represent hydrogen, hydroxyl, nitro, halogen, aryl, and C1~C. 10 Alkyl, C1~C 10 Alkoxy, C1~C 10 Any of the alkylamino groups; Anion - Represents the halogen anion (F - Cl - ,Br - I - ), hexafluorophosphate anion, tetrafluoroborate anion, , , , Any one of them; Y1 represents C1~C 10 Alkyl, C1~C 10 Alkoxy, C1~C 10 Any of the alkylamino groups; Y2 represents hydrogen, hydroxyl, nitro, halogen, aryl, C1~C 10 Alkyl, C1~C 10 Alkoxy, C1~C 10 Any one of the alkylamino groups; R5 represents C1~C 10 Alkyl, C3~C 10 alkenyl, C5-C7 cycloalkyl, C6-C alkyl substituted with at least one specific group 10 Any one of the aryl groups; wherein a specific group is selected from halogen, C1-C4 alkyl, trifluoromethyl, C1-C4 alkoxy, trifluoromethoxy, aryl, or phenoxy; R6, R7, and R8 each independently represent a halogen, C1-C4 alkyl, trifluoromethyl, C1-C4 alkoxy, trifluoromethoxy, aryl, or phenoxy groups. 10 Alkyl, C1~C 10 Any one of the haloalkyl groups.

4. The red photoinitiating system according to claim 1, characterized in that, The selected red sensitive dye Dye-1 is selected from one of the following structures: ； wherein R9, R 10 , R 11 each independently represent C6-Cι4aryl substituted by at least one group selected from the group consisting of halogen, C1-C4alkyl, trifluoromethyl, C1-C4alkoxy, trifluoromethoxy, aryl and phenoxy; 10 aryl: halogen, C1-C4alkyl, trifluoromethyl, C1-C4alkoxy, trifluoromethoxy, aryl or phenoxy; R 12 Representing C1~C 10 Alkyl, C3~C 10 alkenyl, C5-C7 cycloalkyl, C6-C alkyl substituted with at least one specific group 10 Any one of the aryl groups; wherein the specific group can be: halogen, C1~C4 alkyl, trifluoromethyl, C1~C4 alkoxy, trifluoromethoxy, aryl or phenoxy; Cation + represents any one of sodium ion, potassium ion, ; wherein Z1, Z2, Z3, Z4independently represent any one of hydrogen, C1~C 10 alkyl, aryl.

5. The red photoinitiating system according to claim 1, wherein The selected red sensitive dye Dye-2 is selected from one of the following structures: ； The selected diaryliodonium salt is selected from one of the following structures: 。 6. The red photoinitiating system according to claim 1, wherein The selected arylsulfonium salt is selected from one of the following structures: ； The selected triazine compound is selected from one of the following structures: ； The selected alkyl aryl borate and aryl borate are selected from one of the following structures: ； The mass ratio of the first component, the second component and the third component in the red light photoinitiating system is 1:3~100:3~100. 。 7. The red photoinitiating system according to claim 1, wherein 8. The red light photoinitiating system according to any one of claims 1-7 is used in photocuring, specifically: the pre-polymer solution of the red light photoinitiating system and polymerizable monomer is added to the mold, and irradiated with a visible light source with a wavelength range of 600-750 nm; Further, the polymerizable monomer is selected from at least one of alkenyl naphthalene compound, alkenyl anthracene compound, alkenyl benzene compound, acrylic compound, methacrylic compound, acrylate compound, methacrylate compound, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl imidazole, N-vinyl indole, N-vinyl pyrrolidone, trans-N-3-alkynyl butenyl carbazole; Further, the alkenyl benzene compound can be selected from styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl) styrene, p-(bromomethyl) styrene; ​ Further, the methacrylic compound can be methacrylic acid and its derivatives; exemplary, the acrylate compound can be selected from pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-bis(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-diyl bis[(2,6-dibromo-4,1-phenylene)oxy(2-{[3,3,3-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate; Further, 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-bis(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate; Further, the alkenyl anthracene compound can be selected from 2-vinyl anthracene, 9-vinyl anthracene; Further, the alkenyl naphthalene compound can be selected from 1-vinyl naphthalene, 2-vinyl naphthalene.

9. Use of the red photoinitiating system according to any one of claims 1-7 in the preparation of a red-sensitive photopolymer type holographic recording medium; further, the red photoinitiating system accounts for 0.01-5 wt%, preferably 0.1-0.5 wt% of the photopolymer type holographic recording medium.

10. A red-sensitive photopolymer type holographic recording medium, characterized by The raw materials include: Component a) a compound having multiple isocyanate-reactive functional groups; Component b) a polyisocyanate-based compound; Component c) a polymerizable monomer; Component d) the red photoinitiating system according to any one of claims 1-7; Component e) a chain transfer agent; Component f) a catalyst; Component g) an additive; Further, the mass ratio of the component a), component b), component c), component d), component e), component f), component g) is 10-70:10-50:10-60:0.1-5:0.1-3:0.1-3:0.1-7; Further, in the compound having multiple isocyanate-reactive functional groups, the isocyanate-reactive functional group is a hydroxyl group; preferably, it is a compound with low refractive index and two or more hydroxyl functional groups, exemplary, it can be tetraethylene glycol, trimethylol ethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200-2000, polycarbonate polyol, polyether polyol; Further, the polyisocyanate-based compound is a compound having a low refractive index and two or more isocyanate groups, and is exemplified by hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate; Further, the polymerizable monomer is selected from at least one of an alkenyl naphthalene compound, an alkenyl anthracene compound, an alkenyl benzene compound, an acrylic acid compound, a methacrylic acid compound, an acrylate compound, a methacrylate compound, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazole, N-vinylindole, N-vinylpyrrolidone, and trans-N-3-alkynylbutenylcarbazole; Exemplarily, the alkenyl benzene compound can be selected from styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene; Exemplarily, the methacrylic acid compound can be methacrylic acid and a derivative thereof; and exemplarily, the acrylate compound can be selected from pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-bis(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-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate; 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-bis(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate; Exemplarily, the alkenyl anthracene compound is selected from 2-vinylanthracene and 9-vinylanthracene; Exemplarily, the alkenyl naphthalene compound is selected from 1-vinyl naphthalene and 2-vinyl naphthalene; Further, the chain transfer agent is a thiol compound, including but not limited to one or more of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, and the like; Further, the catalyst is a tertiary amine catalyst or an organometallic catalyst, including but not limited to triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropylenediamine, N,N-bis(dimethylaminopropyl) isopropanolamine, dibutyl tin dilaurate, stannous octoate, a potassium carboxylate catalyst, and a bismuth carboxylate catalyst; Further, the additive includes one or more of a defoaming agent, a leveling agent, a plasticizer, and a water removal agent; Illustratively, the defoaming agent is a silicone defoaming agent, 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 any proportion mixture of these defoaming agents; Illustratively, the leveling agent is a silicone surface aid, 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 any proportion mixture of these surface aids; Illustratively, the plasticizer is toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate, or any proportion mixture of these compounds; Illustratively, the water removal agent includes but is not limited to p-tolylsulfonylisocyanate, triethyl orthoformate, CUWR-WB20 water removal agent produced by Guangzhou Yourun Synthetic Material Co., Ltd., ALT-201 water removal agent produced by Anxiang Elite Chemical Co., Ltd., PCCI water removal agent produced by Shanghai Lur Chemical Industry Trade Co., Ltd.

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