Photopolymer composition, hologram recording medium, method for preparing same, and optical element comprising same

Abstract

The present application relates to a photopolymer composition, a hologram recording medium, a method for preparing same, and an optical element comprising same. The photopolymer composition can provide a hologram recording medium having excellent optical recording properties such as diffraction efficiency while securing colorless and transparent optical properties and excellent thermal stability, and an optical element comprising same.

Description

Photopolymer composition, holographic recording medium, method for producing same, and optical element including same

[0001] [Cross-reference with related application(s)]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0022502, filed February 16, 2024, Korean Patent Application No. 10-2024-0022503, filed February 16, 2024, Korean Patent Application No. 10-2024-0022504, filed February 16, 2024, and Korean Patent Application No. 10-2025-0019407, filed February 14, 2025, the entire contents of which are incorporated herein by reference.

[0003] The present application relates to a photopolymer composition, a holographic recording medium, a method for producing the same, and an optical device including the same.

[0004] A holographic recording medium records information by changing the refractive index within the holographic recording layer through an exposure process, and reproduces the information by reading the difference in the recorded refractive index.

[0005] In this regard, the photopolymer composition can be used to manufacture a hologram. The photopolymer can easily store an optical interference pattern as a hologram by photopolymerization of a photoreactive monomer. Therefore, the photopolymer can be used in various fields, such as smart devices such as mobile devices, components of wearable displays, automotive products (e.g., head-up displays), holographic fingerprint recognition systems, holographic optical elements having the functions of optical lenses, mirrors, deflecting mirrors, filters, diffusion screens, diffractive members, light guides, waveguides, projection screens, and / or masks, media for optical memory systems, optical diffusers, optical wavelength splitters, reflective and transmissive color filters, etc.

[0006] Specifically, a photopolymer composition for hologram production comprises a polymer matrix, a photoreactive monomer, and a photoinitiator system. Then, a photopolymer layer produced from this composition is irradiated with laser interference light to induce local photopolymerization of the monomer.

[0007] This local photopolymerization process creates a refractive index modulation, which in turn creates a diffraction grating. The refractive index modulation value (△n) is influenced by the thickness and diffraction efficiency (DE) of the photopolymer layer, and the angular selectivity broadens as the thickness decreases.

[0008] Recently, there has been an increasing demand for the development of materials that can maintain high diffraction efficiency and stable holograms, and various attempts are being made to manufacture holographic recording media that have a thin thickness but high diffraction efficiency and refractive index modulation value.

[0009] According to one embodiment of the present invention, a photopolymer composition is provided.

[0010] According to another embodiment of the present invention, a photopolymer composition is provided.

[0011] According to another embodiment of the present invention, a holographic recording medium is provided.

[0012] According to another embodiment of the present invention, a method for manufacturing the holographic recording medium is provided.

[0013] According to another embodiment of the present invention, an optical element including the holographic recording medium is provided.

[0014] Hereinafter, a photopolymer composition, a holographic recording medium, a method for manufacturing the same, and an optical element including the same according to specific embodiments of the invention will be described.

[0015] As used herein, “hologram recording medium” means a medium or media capable of recording optical information in the entire visible light range and the ultraviolet range (e.g., 300 to 1,200 nm) through an exposure process, unless specifically stated otherwise. For example, the holograms used herein may include any visual hologram, such as an in-line (Gabor) hologram, an off-axis hologram, a full-aperture pre-hologram, a white-light transmission hologram (“rainbow hologram”), a Denisyuk hologram, a biaxial reflection hologram, an edge-literature hologram, or a holographic stereogram.

[0016] In this specification, with respect to environmental conditions in which a holographic recording medium or a device including the same is placed, “high temperature” may mean a temperature of 60°C or higher. For example, the high temperature may mean a temperature of 65°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, or 90°C or higher, and the upper limit thereof is not particularly limited, but may be, for example, 110°C or lower, 105°C or lower, 100°C or lower, 95°C or lower, 90°C or lower, 85°C or lower, or 80°C or lower. When temperature affects the characteristics of a substance, object, or each component, unless specifically mentioned otherwise, the temperature conditions under which the characteristics are measured or described may mean room temperature (e.g., a temperature at which no special cooling or heating is performed, in the range of about 15 to 30°C).

[0017] In this specification, unless specifically stated otherwise, the measurement values ​​may be understood as measurement values ​​of a photopolymer layer included in a holographic recording medium.

[0018] According to one embodiment of the invention, a polymer matrix or a precursor thereof; a photoreactive monomer; a photosensitive dye; and a co-initiator, wherein the photosensitive dye is a compound including a core represented by the following chemical formula 1, wherein the openness of a double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 A photopolymer composition comprising a phosphorus compound is provided.

[0019] [Chemical Formula 1]

[0020]

[0021] In the above chemical formula 1,

[0022] Z is oxygen, sulfur or CR 7 R 8 And,

[0023] R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

[0024]

[0025] For holographic recording media to be utilized in diverse applications, they must be capable of optical recording in the red, green, and blue regions. However, previously developed photosensitizing dyes for blue-region optical recording have inferior optical recording properties compared to those for red and green regions, and their thermal stability is particularly poor, making them unsuitable for holographic recording media prone to exposure to high-temperature environments.

[0026] The present inventors have developed a compound comprising a core represented by the above chemical formula 1 as a photosensitive dye, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 By applying a compound of phosphorus, optical recording in the blue region is possible, and by confirming the openness of a specific double bond included in the core, a holographic recording medium with excellent optical recording characteristics and thermal stability can be provided, thereby completing the present invention.

[0027]

[0028] Hereinafter, a photopolymer composition according to one embodiment of the present invention, a hologram recording medium formed from the photopolymer composition, a method for manufacturing the same, and an optical element including the hologram recording medium will be described in detail.

[0029] The photopolymer composition of the above embodiment comprises a polymer matrix or a precursor thereof that serves as a support for a photopolymer layer formed therefrom.

[0030] The polymer matrix is ​​formed by crosslinking a siloxane polymer containing a silane functional group (Si-H) and an acrylic polyol. Specifically, the polymer matrix is ​​formed by crosslinking an acrylic polyol with a siloxane polymer containing a silane functional group. More specifically, the hydroxyl group of the acrylic polyol can form a crosslinking bond through a hydrosilylation reaction with the silane functional group of the siloxane polymer. The hydrosilylation reaction can proceed rapidly even at room temperature (for example, a temperature in the range of about 15 to 30°C in a heated or non-heated state) in the presence of a Pt-based catalyst. Therefore, the photopolymer composition of one embodiment can improve the manufacturing efficiency or productivity of a hologram recording medium by employing a polymer matrix that can be rapidly crosslinked even at room temperature as a support.

[0031] The polymer matrix described above can enhance the mobility of components (e.g., photoreactive monomers or plasticizers) included in the photopolymer layer due to the flexible main chain of the siloxane-based polymer. In addition, the siloxane bond, which has excellent heat and moisture resistance properties, can facilitate securing the reliability of the photopolymer layer on which optical information is recorded and the holographic recording medium including the same.

[0032] The polymer matrix may have a relatively low refractive index, and thus may serve to increase the refractive index modulation of a layer formed from the photopolymer composition. For example, the upper limit of the refractive index of the polymer matrix may be 1.53 or less, 1.52 or less, 1.51 or less, 1.50 or less, or 1.49 or less. And, the lower limit of the refractive index of the polymer matrix may be, for example, 1.40 or more, 1.41 or more, 1.42 or more, 1.43 or more, 1.44 or more, 1.45 or more, or 1.46 or more. In the present specification, "refractive index" may be a value measured with an Abbe refractometer at 25°C.

[0033] The photopolymer composition of the above embodiment may include the polymer matrix in the crosslinked form described above or a precursor thereof. When the photopolymer composition includes a precursor of the polymer matrix, it may include a siloxane-based polymer, an acrylic polyol, and a Pt-based catalyst.

[0034] The above siloxane polymer may include, for example, a repeating unit represented by the following chemical formula 2 and a terminal group represented by the following chemical formula 3.

[0035] [Chemical Formula 2]

[0036]

[0037] In the above chemical formula 2,

[0038] Multiple R's 11 and R 12 are the same or different from each other, and each independently represents hydrogen, halogen, or an alkyl group having 1 to 10 carbon atoms,

[0039] k is an integer between 1 and 10,000,

[0040] [Chemical Formula 3]

[0041]

[0042] In the above chemical formula 3,

[0043] Multiple R's 13 Inland R 15 are the same or different from each other, and each independently represents hydrogen, halogen, or an alkyl group having 1 to 10 carbon atoms,

[0044] At least one repeating unit selected from among the repeating units represented by the above chemical formula 2 and R of one terminal group selected from among the terminal groups represented by the above chemical formula 3 11 Inland R 15 At least one of them is hydrogen.

[0045] In the above chemical formula 3, -(O)- means that when Si of the terminal group represented by the above chemical formula 3 is bonded to the repeating unit represented by the above chemical formula 2, it is bonded via oxygen (O) or directly without oxygen (O).

[0046] In this specification, “alkyl group” may be a straight-chain, branched-chain or cyclic alkyl group. By way of non-limiting example, the term “alkyl group” herein includes methyl, ethyl, propyl (e.g., n-propyl, isopropyl, etc.), butyl (e.g., n-butyl, isobutyl, tert-butyl, sec-butyl, cyclobutyl, etc.), pentyl (e.g., n-pentyl, isopentyl, neopentyl, tert-pentyl, 1,1-dimethyl-propyl, 1-ethyl-propyl, 1-methyl-butyl, cyclopentyl, etc.), hexyl (e.g., n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methylpentyl, 3,3-dimethylbutyl, 1-ethyl-butyl, 2-ethylbutyl, cyclopentylmethyl, cyclohexyl, etc.), heptyl (e.g., n-heptyl, 1-methylhexyl, 4-methylhexyl, 5-methylhexyl, cyclohexylmethyl, etc.), It can be octyl (e.g., n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, etc.), nonyl (e.g., n-nonyl, 2,2-dimethylheptyl, etc.), etc.

[0047] For example, R of the above chemical formulas 2 and 3 11 Inland R 15 is methyl or hydrogen, and plural R 11 Inland R 15At least two of them may be hydrogen. More specifically, the siloxane polymer is R of the chemical formula 2. 11 and R 12 are methyl and hydrogen, respectively, and R of the above chemical formula 3 13 Inland R 15 A compound in which each independently represents methyl or hydrogen (e.g., polymethylhydrosiloxane in which the terminal group is a trimethylsilyl group or a dimethylhydrosilyl group); some R of the above chemical formula 2 11 and R 12 are methyl and hydrogen respectively, and the remaining R 11 and R 12 All are methyl, and R of the above chemical formula 3 13 Inland R 15 A compound in which each independently represents methyl or hydrogen (e.g., poly(dimethylsiloxane-co-methylhydrosiloxane) in which the terminal group is a trimethylsilyl group or a dimethylhydrosilyl group); or R of the above formula 2 11 and R 12 All are methyl, and R of the above chemical formula 3 13 Inland R 15 It may be a compound in which at least one of the terminal groups is hydrogen and the others are each independently methyl or hydrogen (e.g., polydimethylsiloxane in which one or both of the terminal groups are dimethylhydrosilyl groups).

[0048] The above siloxane compound may have, for example, a number average molecular weight (Mn) in the range of 200 to 4,000. Specifically, the lower limit of the number average molecular weight of the siloxane polymer may be, for example, 200 or more, 250 or more, 300 or more, or 350 or more, and the upper limit may be, for example, 3,500 or less, 3,000 or less, 2,500 or less, 2,000 or less, 1,500 or less, or 1,000 or less. When the number average molecular weight of the above siloxane polymer satisfies the above range, problems such as a decrease in the degree of matrix crosslinking due to volatilization of the siloxane polymer during the crosslinking process with the acrylic polyol at room temperature or a higher temperature, or a phase separation occurring with other components of the photopolymer composition due to poor compatibility of the siloxane polymer with these components can be prevented, thereby enabling the hologram recording medium formed from the photopolymer composition to exhibit excellent optical recording characteristics and excellent durability under high-temperature conditions.

[0049] The above number average molecular weight refers to the number average molecular weight (unit: g / mol) converted to polystyrene as measured by the GPC method. In the process of measuring the number average molecular weight converted to polystyrene as measured by the GPC method, a commonly known analysis device and a detector such as a refractive index detector and an analysis column can be used, and commonly applied temperature conditions, solvents, and flow rates can be applied. Specific examples of the above measurement conditions include a temperature of 25°C, a tetrahydrofuran solvent, and a flow rate of 1 mL / min.

[0050] The above acrylic polyol may refer to a polymer having one or more, specifically two or more, hydroxyl groups bonded to the main chain or side chain of an acrylate polymer. In the present specification, "acrylic" refers to at least one selected from acryloyl groups, methacryloyl groups, and derivatives thereof, or a repeating unit formed by polymerization thereof, unless specifically stated otherwise, and "acrylate" refers to at least one selected from acrylates and methacrylates, or a repeating unit formed by polymerization thereof, unless specifically stated otherwise.

[0051] The above acrylic polyol may be a homopolymer of an acrylate monomer having a hydroxyl group, a copolymer of two or more acrylate monomers having hydroxyl groups, or a copolymer of an acrylate monomer having a hydroxyl group and an acrylate monomer not having a hydroxyl group. In this specification, “copolymer” is a term encompassing all random copolymers, block copolymers, and graft copolymers, unless specifically stated otherwise.

[0052] As the acrylate monomer having the above hydroxyl group, examples thereof include hydroxyalkyl (meth)acrylate or hydroxyaryl (meth)acrylate, and the like, wherein the alkyl is an alkyl having 1 to 30 carbon atoms, and the aryl may be an aryl having 6 to 30 carbon atoms. In addition, as the acrylate monomer not having the above hydroxyl group, examples thereof include alkyl (meth)acrylate or aryl (meth)acrylate, and the like, wherein the alkyl is an alkyl having 1 to 30 carbon atoms, and the aryl may be an aryl having 6 to 30 carbon atoms. In the present specification, “(meth)acrylate” is a term referring to acrylate and / or methacrylate, unless specifically stated otherwise.

[0053] The above-mentioned acrylic polyol may have, for example, a weight average molecular weight (Mw) within the range of 150,000 to 1,000,000. The weight average molecular weight refers to a weight average molecular weight in terms of polystyrene measured by the GPC method described above. For example, the lower limit of the weight average molecular weight may be 150,000 or more, 200,000 or more, or 250,000 or more, and the upper limit may be, for example, 900,000 or less, 850,000 or less, 800,000 or less, 750,000 or less, 700,000 or less, 650,000 or less, 600,000 or less, 550,000 or less, 500,000 or less, or 450,000 or less. When the weight average molecular weight of the acrylic polyol satisfies the above range, the polymer matrix sufficiently functions as a support, so that even with the passage of time in use, the decrease in recording characteristics for optical information is small, and sufficient flexibility is provided to the polymer matrix to improve the mobility of components (e.g., photoreactive monomers or plasticizers) included in the photopolymer composition, thereby minimizing the decrease in recording characteristics for optical information.

[0054] In order to adjust the crosslinking density of the acrylic polyol by the siloxane polymer to a level advantageous for securing the function of the hologram recording medium, the hydroxyl equivalent of the acrylic polyol can be adjusted to an appropriate level.

[0055] Specifically, the hydroxyl group (-OH) equivalent of the acrylic polyol may be, for example, in the range of 500 to 3,000 g / equivalent. More specifically, the lower limit of the hydroxyl group (-OH) equivalent of the acrylic polyol may be 600 g / equivalent or more, 700 g / equivalent or more, 800 g / equivalent or more, 900 g / equivalent or more, 1000 g / equivalent or more, 1100 g / equivalent or more, 1200 g / equivalent or more, 1300 g / equivalent or more, 1400 g / equivalent or more, 1500 g / equivalent or more, 1600 g / equivalent or more, 1700 g / equivalent or more, or 1750 g / equivalent or more. And, the upper limit of the hydroxyl group (-OH) equivalent of the acrylic polyol may be 2900 g / equivalent or less, 2800 g / equivalent or less, 2700 g / equivalent or less, 2600 g / equivalent or less, 2500 g / equivalent or less, 2400 g / equivalent or less, 2300 g / equivalent or less, 2200 g / equivalent or less, 2100 g / equivalent or less, 2000 g / equivalent or less, or 1900 g / equivalent or less. The hydroxyl group (-OH) equivalent of the acrylic polyol is the equivalent (g / equivalent) for one hydroxyl functional group, and is a value obtained by dividing the weight average molecular weight of the acrylic polyol by the number of hydroxyl functional groups per molecule. The smaller the equivalent value, the higher the density of the functional group, and the larger the equivalent value, the smaller the density of the functional group.When the hydroxyl group (-OH) equivalent of the above acrylic polyol satisfies the above range, the polymer matrix has an appropriate crosslinking density and sufficiently functions as a support, and the fluidity of the components included in the layer formed from the photopolymer composition is improved, so that the initial refractive index modulation value is maintained at an excellent level even after time passes without the problem of the boundary surface of the diffraction gratings generated after recording collapsing, thereby minimizing the decrease in recording characteristics for optical information.

[0056] The above acrylic polyol may have a glass transition temperature (Tg) in the range of, for example, -60 to -10°C. Specifically, the lower limit of the glass transition temperature may be, for example, -55°C or higher, -50°C or higher, -45°C or higher, -40°C or higher, -35°C or higher, -30°C or higher, or -25°C or higher, and the upper limit may be, for example, -15°C or lower, -20°C or lower, -25°C or lower, -30°C or lower, or -35°C or lower. When the above glass transition temperature range is satisfied, the glass transition temperature may be lowered without significantly lowering the modulus of the polymer matrix, thereby increasing the mobility (fluidity) of other components in the photopolymer composition and also improving the moldability of the photopolymer composition. The above glass transition temperature can be measured using a known method, for example, a method such as DSC (Differential Scanning Calorimetry) or DMA (dynamic mechanical analysis).

[0057] The refractive index of the acrylic polyol may be, for example, 1.40 or more and less than 1.50. Specifically, the lower limit of the refractive index of the acrylic polyol may be, for example, 1.41 or more, 1.42 or more, 1.43 or more, 1.44 or more, 1.45 or more, or 1.46 or more, and the upper limit may be, for example, 1.49 or less, 1.48 or less, 1.47 or less, 1.46 or less, or 1.45 or less. When the acrylic polyol has a refractive index in the above-described range, it may contribute to increasing refractive index modulation. The refractive index of the acrylic polyol is a theoretical refractive index and may be calculated using the refractive index of a monomer used in producing the acrylic polyol (a value measured using an Abbe refractometer at 25°C) and the fraction (mole ratio) of each monomer.

[0058] The above acrylic polyol and siloxane polymer may be used so that the molar ratio (SiH / OH) of the silane functional group (Si-H) of the siloxane polymer to the hydroxyl group (-OH) of the acrylic polyol is 0.80 to 3.5. That is, the type and content of the siloxane polymer and the acrylic polyol may be selected so as to satisfy the molar ratio when forming the polymer matrix. The lower limit of the molar ratio (SiH / OH) may be, for example, 0.81 or more, 0.85 or more, 0.90 or more, or 0.95 or more, and the upper limit may be, for example, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3.05 or less, or 3.0 or less. When the above molar ratio (SiH / OH) range is satisfied, the polymer matrix is ​​crosslinked at an appropriate crosslinking density, thereby improving reliability under high temperature conditions and implementing a sufficient refractive index modulation value.

[0059] The above Pt series catalyst may be, for example, Karstedt's catalyst. The polymer matrix precursor may additionally include, in addition to the Pt series catalyst, a non-metal series catalyst such as a Rhodium series, an Iridium series, a Rhenium series, a Molybdenum series, an Iron series, a Nickel series, an alkali metal or alkaline earth metal series, a Lewis acid series, or a Carbene series, as needed.

[0060] Meanwhile, a holographic recording medium can be manufactured by irradiating an object light and a reference light onto a photopolymer layer formed from the photopolymer composition of the above embodiment. Due to the interference field of the object light and the reference light, photopolymerization of the photoreactive monomer does not occur in the destructive interference region, but photopolymerization of the photoreactive monomer occurs in the constructive interference region. As the photoreactive monomer is continuously consumed in the constructive interference region, a concentration difference occurs between the photoreactive monomers in the destructive interference region and the constructive interference region, and as a result, the photoreactive monomers in the destructive interference region diffuse into the constructive interference region. A diffraction grating is generated by the refractive index modulation generated in this way.

[0061] Accordingly, the photoreactive monomer may include a compound having a higher refractive index than the polymer matrix in order to implement the above-described refractive index modulation. However, it is not limited to all photoreactive monomers included in the photopolymer composition of the above embodiment having a higher refractive index than the polymer matrix, and at least some photoreactive monomers may have a higher refractive index than the polymer matrix in order to implement a high refractive index modulation value. For example, the photoreactive monomer may include a monomer having a refractive index of 1.50 or more, 1.51 or more, 1.52 or more, 1.53 or more, 1.54 or more, 1.55 or more, 1.56 or more, 1.57 or more, 1.58 or more, 1.59 or more, or 1.60 or more but 1.70 or less.

[0062] The photoreactive monomer may include at least one monomer selected from the group consisting of a monofunctional monomer having one photoreactive functional group and a polyfunctional monomer having two or more photoreactive functional groups. In this case, the photoreactive functional group may be, for example, a (meth)acryloyl group, a vinyl group, or a thiol group. More specifically, the photoreactive functional group may be a (meth)acryloyl group.

[0063] The above monofunctional monomers include, for example, benzyl (meth)acrylate (Miwon's M1182 refractive index 1.5140), benzyl 2-phenylacrylate, phenoxybenzyl (meth)acrylate (Miwon's M1122 refractive index 1.565), phenol (ethylene oxide) (meth)acrylate (phenol (EO) (meth)acrylate; Miwon's M140 refractive index 1.516), phenol (ethylene oxide) 2 (meth)acrylate (phenol (EO) 2 (meth)acrylate; Miwon's M142 refractive index 1.510), O-phenylphenol (ethylene oxide) (meth)acrylate (O-phenylphenol (EO) (meth)acrylate; Miwon's M1142 refractive index 1.577), and phenylthioethyl (meth)acrylate (Miwon's M1162 refractive index 1.560) and biphenylmethyl (meth)acrylate.

[0064] The above multifunctional monomer is, for example, bisphenol A (ethylene oxide). 2~10 Di(meth)acrylate (bisphenol A (EO) 2~10(meth)acrylate; Miwon's M240 refractive index 1.537, M241 refractive index 1.529, M244 refractive index 1.545, M245 refractive index 1.537, M249 refractive index 1.542, M2100 refractive index 1.516, M2101 refractive index 1.512), bisphenol A epoxy di(meth)acrylate (Miwon's PE210 refractive index 1.557, PE2120A refractive index 1.533, PE2120B refractive index 1.534, PE2020C refractive index 1.539, PE2120S refractive index 1.556), bisfluorene di(meth)acrylate (Miwon's HR6022 refractive index 1.600, HR6040 refractive index 1.600, HR6042 refractive index 1.600), modified bisphenol fluorene di(meth)acrylate (Miwon's HR 6060 refractive index 1.584, HR6100 refractive index 1.562, HR6200 refractive index 1.530), tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate (Miwon's M370 refractive index 1.508), phenol novolac epoxy (meth)acrylate (Miwon's SC6300 refractive index 1.525), and cresol novolac epoxy (meth)acrylate (Miwon's SC6400 refractive index 1.522, SC6400C refractive index 1.522).

[0065] The photopolymer composition of the above embodiment may contain 50 to 300 parts by weight of the photoreactive monomer based on 100 parts by weight of the polymer matrix. For example, the lower limit of the content of the photoreactive monomer may be 50 parts by weight or more, 60 parts by weight or more, 70 parts by weight or more, 80 parts by weight or more, or 90 parts by weight or more, and the upper limit may be 300 parts by weight or less, 280 parts by weight or less, 250 parts by weight or less, 220 parts by weight or less, 200 parts by weight or less, 190 parts by weight or less, or 180 parts by weight or less. When the above range is satisfied, it is advantageous to secure excellent optical recording characteristics and durability in a high-temperature environment.

[0066] In this specification, the content of the polymer matrix means the sum of the contents (weight) of the acrylic polyol and the siloxane polymer forming the matrix. In other words, the content of the polymer matrix means including both the polymer matrix formed by cross-linking the acrylic polyol and the siloxane polymer and some non-cross-linked polymer matrix precursor.

[0067] The photopolymer composition of the above embodiment comprises a photosensitive dye and a coinitiator so as to initiate polymerization by light.

[0068] The above-mentioned photosensitive dye is a compound including a core represented by the following chemical formula 1, and the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 It may contain human compounds.

[0069] [Chemical Formula 1]

[0070]

[0071] In the above chemical formula 1,

[0072] Z is oxygen, sulfur or CR 7 R 8 And,

[0073] R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

[0074] The core of the above chemical formula 1 has two heterocycles ( ) has a structure connected through a double bond indicated by a dotted circle.

[0075] The core of the above chemical formula 1 is the parent of the compound containing it, and in the above chemical formula 1, means a bond connecting to hydrogen or a substituent.

[0076] A compound containing the core of the above chemical formula 1, wherein the openness of the double bond (indicated by a dotted circle) connecting two hetero rings is 7.0 to 8.5 Å. 2 The use of phosphorus compounds can significantly improve the thermal stability of holographic recording media prior to recording.

[0077] The openness of the above double bond may be a value calculated by calculating the openness for each of the two carbon atoms forming the double bond and adding them up.

[0078] The openness of the above carbon atom is defined as the area of ​​the empty surface area at a certain distance from the carbon atom. Specifically, the openness is defined as the area of ​​the open surface area not covered by the substituent with respect to the surface area of ​​a sphere having a radius of a certain distance r from the carbon atom. Here, the certain distance means a distance of about 1.0 to 1.4 Å or about 1.2 Å with the carbon atom as the center. Therefore, the openness of the carbon atom may be the area of ​​the open surface area not covered by the substituent with respect to the surface area of ​​a sphere having a radius of about 1.0 to 1.4 Å or about 1.2 Å from the carbon atom.

[0079] The above openness can be calculated using Jmol software for structures optimized by a quantum chemistry calculation program. Specifically, the openness is calculated using density functional theory within the quantum chemistry calculation program, with B3LYP as the functional and 6-31G as the basis function. * It can be calculated using Jmol software, and can be calculated by referring to the calculation method described in detail in the test example described below.

[0080] The openness of the above double bond is 7.0 to 8.5 Å. 2This can be understood to mean that the double bond is covered by the substituents, which makes it difficult for other components of the holographic recording medium to access the double bond, thus reducing the possibility of causing a side reaction.

[0081] However, contrary to the prediction that the smaller the openness of the double bond, the better the thermal stability, the experimental results of the present inventors confirmed that when the openness of the double bond decreases below a certain level, the thermal stability actually deteriorates and the optical recording characteristics and transparency deteriorate. In other words, a holographic recording medium with excellent thermal stability before recording can be provided only when the openness of the double bond has a specific value.

[0082] The upper openness limit for the above double bond is, for example, 8.50 Å 2 Below, 8.45 Å 2 Below, 8.43 Å 2 or less than 8.41 Å 2 It can be less than or equal to 7.0 Å, for example. 2 Above, 7.5 Å 2 Above, 8.0 Å 2 or more than 8.1 Å 2 It could be strange.

[0083] A compound comprising a core represented by the above chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 A specific example of a phosphorus compound is a compound represented by the following chemical formula 1-1.

[0084] [Chemical Formula 1-1]

[0085]

[0086] In the above chemical formula 1-1,

[0087] R 1 is an alkylene group having 1 to 6 carbon atoms, and R 2 is an alkyl group having 1 to 6 carbon atoms,

[0088] n1 is an integer from 1 to 6,

[0089] R 3 is an alkyl group having 3 to 12 carbon atoms,

[0090] R 4 is hydrogen or an alkyl group having 1 to 6 carbon atoms,

[0091] R 5 and R 6 are each independently a halogen, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

[0092] n2 and n3 are each independently integers from 0 to 4,

[0093] Z is oxygen, sulfur or CR 7 R 8 And,

[0094] R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

[0095] In the above chemical formula 1-1, R 1 For example, R may be a methylene group, a 1,2-ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 1,4-butylene group, a 1,3-butylene group, a 1,2-butylene group or an isobutylene group. Specifically, R 1 For example, R may be a 1,2-ethylene group, a 1,2-propylene group, or an isobutylene group. More specifically, R 1 For example, it can be a 1,2-ethylene group.

[0096] In the above chemical formula 1-1, R 2 can be a methyl group, an ethyl group, n-propyl, isopropyl, 1-butyl, 2-butyl, isobutyl or t-butyl. Specifically, R 2 For example, it can be a methyl group, an ethyl group or an n-propyl group. More specifically, R 2 For example, it can be a methyl group.

[0097] In the above chemical formula 1-1, n1 can be, for example, an integer of 1 to 4, an integer of 1 to 3, or an integer of 1 to 2.

[0098] In the above chemical formula 1-1, R 3 Silver may be, for example, a branched or cyclic alkyl group having 3 to 12 carbon atoms. More specifically, R 3 Silver may be, for example, isopropyl, isobutyl, t-butyl, isopentyl, 1-methyl-1-butyl, 2-methyl-2-butyl, t-pentyl, isohexyl, 1-methyl-1-pentyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, t-hexyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl, cyclopropylethyl, cyclobutylethyl, cyclopentylethyl or cyclohexylethyl. More specifically, R 3 Silver may be, for example, isopropyl, isobutyl, t-butyl, isopentyl, isohexyl, 2,2-dimethyl-1-butyl or 3,3-dimethyl-1-butyl.

[0099] In the above chemical formula 1-1, R 4 Silver can be, for example, hydrogen, a methyl group or an ethyl group. More specifically, R 4 Silver, for example, can be hydrogen.

[0100] In the above chemical formula 1-1, R 5 and R 6 For example, each independently may be a halogen, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. More specifically, R 5 and R 6 For example, each independently may be fluorine, chlorine, a methyl group, an ethyl group, a methoxy group or an ethoxy group.

[0101] In the above chemical formula 1-1, n2 and n3 are, for example, each independently an integer from 0 to 4, an integer from 0 to 3, an integer from 0 to 2, an integer from 0 to 1, or 0.

[0102] In the above chemical formulas 1 and 1-1, Z is, for example, oxygen, sulfur or CR. 7 R 8 and R 7 and R 8 are each independently an alkyl group having 1 to 3 carbon atoms. Specifically, Z is, for example, oxygen, sulfur, or a 2,2-propylene group. More specifically, Z is, for example, a 2,2-propylene group.

[0103] The above-described photosensitizing dye may additionally include an anion as a counter ion of a compound including a core represented by the above-described chemical formula 1, which is a cation. The type of the anion is not particularly limited, but may be, for example, tetraaryl borate. The four aryl groups of the tetraaryl borate may be the same as or different from each other, and may be, for example, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 30 carbon atoms, or a substituted or unsubstituted alkylaryl group having 7 to 30 carbon atoms.

[0104] As used herein, “substituted or unsubstituted” means that hydrogen or carbon is replaced with another element, unless otherwise specifically defined. As non-limiting examples, hydrogen may be substituted with a halogen, a vinyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, and carbon (-CH2-) may be replaced with -O- or -CO-.

[0105] For example, the tetraaryl borate may be at least one anion selected from the group consisting of tetraphenyl borate, tetrakis(fluorophenyl) borate, tetrakis(chlorophenyl) borate, tetrakis(methylphenyl) borate, tetrakis(methoxyphenyl) borate, tetrakis(fluoromethylphenyl) borate, tetrakis(fluoromethoxyphenyl), tetrakis(chloromethylphenyl) borate, and tetrakis(chloromethoxyphenyl) borate.

[0106] A compound comprising a core represented by the above chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 When a phosphorus compound is used as a photosensitizing dye, optical recording in the blue region is possible, and a holographic recording medium with excellent optical recording characteristics and thermal stability can be provided.

[0107] The photopolymer composition according to the above embodiment is a compound including a core represented by the above chemical formula 1, and the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 In addition to the phosphorus compound, a photosensitizing dye capable of optical recording in the blue, red or green region may be additionally included.

[0108] The above-mentioned photosensitizing dyes include, for example, silicon rhodamine compounds, sulfonium derivatives of ceramidonine, new methylene blue, thioerythrosine triethylammonium, 6-acetylamino-2-methylceramidonin, eosin, erythrosine, rose bengal, thionine, basic yellow, pinacynol chloride, rhodamine 6G, gallocyanine, ethyl violet, Victoria blue R, Celestine blue, QuinaldineRed, and crystal. It may include at least one selected from the group consisting of crystal violet, brilliant green, astrazon orange G, darrow red, pyronin Y, basic red 29, pyrylium iodide, safranin O, cyanine, methylene blue, Azure A, and BODIPY. The astrazon orange G is a compound including a core represented by the chemical formula 1, or an openness of a double bond connecting two hetero rings of 9.99 Å. 2 As a compound, it does not exhibit the optical recording properties and thermal stability intended in the present application.

[0109] The photopolymer composition of the above embodiment may contain the photosensitive dye in an amount ranging from 0.01 to 10 parts by weight based on 100 parts by weight of the polymer matrix. Specifically, the lower limit of the content of the photosensitive dye may be, for example, 0.05 parts by weight or more, 0.07 parts by weight or more, or 0.10 parts by weight or more, and the upper limit may be, for example, 5 parts by weight or less. When the above range is satisfied, it is advantageous to secure the desired optical recording characteristics by exhibiting an appropriate polymerization reaction speed.

[0110] The above public agent may be an electron donor, an electron acceptor, or a mixture thereof.

[0111] For example, the photopolymer composition of the above embodiment may include an electron donor as a public initiator. The electron donor may include, for example, a borate anion represented by the following chemical formula 4.

[0112] [Chemical Formula 4]

[0113] BX 1 X 2 X 3 X 4

[0114] In the above chemical formula 4, X 1 Inland X 4 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 30 carbon atoms, a substituted or unsubstituted alkylaryl group having 7 to 30 carbon atoms, or a substituted or unsubstituted allyl group, X 1 Inland X 4 At least one of them is not an aryl group.

[0115] When the above-mentioned alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, aryl group having 6 to 30 carbon atoms, arylalkyl group having 7 to 30 carbon atoms, alkylaryl group having 7 to 30 carbon atoms or allyl group is substituted, it may be substituted with one or more selected from the group consisting of a halogen, a vinyl group, a haloalkyl group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms.

[0116] Specifically, X 1 Inland X 3 may be phenyl, methylphenyl, biphenyl, naphthyl or methylnaphthyl, each independently substituted or unsubstituted with one or more substituents selected from the group consisting of halogen, vinyl and methoxy groups, and X 4 may be a straight-chain alkyl group having 1 to 12 carbon atoms.

[0117] For example, the above-described public offering may include one or more borate anions selected from the group consisting of borate anions represented by the following chemical formulas 4-1 and 4-2.

[0118] [Chemical Formula 4-1]

[0119]

[0120] In the above chemical formula 4-1,

[0121] R 102 , R 103 and R 104 are each independently hydrogen, methyl, methoxy, halogen, phenyl or vinyl,

[0122] X 4' is a straight-chain alkyl group having 1 to 12 carbon atoms.

[0123] [Chemical Formula 4-2]

[0124]

[0125] In the above chemical formula 4-2,

[0126] R 106are each independently hydrogen, methyl, methoxy, halogen or vinyl,

[0127] X 4" is a straight-chain alkyl group having 1 to 12 carbon atoms.

[0128] In the above chemical formulas 4-1 and 4-2, multiple R 102 , R 103 , R 104 and R 106 may be the same or different from each other. For example, in the above chemical formula 4-1, two R substituted on one phenyl group 103 can be identical or different, and two R 104 They can also be identical or different.

[0129] In the above chemical formula 4-1, R 102 , R 103 and R 104 For example, each can independently be hydrogen, F, Cl or a methyl group. Specifically, R 102 , for example, can each independently be hydrogen or Cl. R 103 Silver, for example, can be hydrogen. R 104 can be, for example, hydrogen, Cl or a methyl group. More specifically, R 102 can be, for example, Cl. R 103 Silver, for example, can be hydrogen. R 104 may be, for example, hydrogen or a methyl group.

[0130] In the above chemical formula 4-1, X 4' For example, it can be a butyl group, a pentyl group, a hexyl group, a heptyl group or an octyl group.

[0131] In the above chemical formula 4-2, R 106 For example, each can independently be hydrogen, halogen or methyl group. Specifically, R 106 For example, each independently can be hydrogen, F, Cl or a methyl group.

[0132] The cation combined with the above borate anion may be one or more cations selected from the group consisting of alkali metal cations, quaternary ammonium cations, and nitrogen-containing heterocyclic cations that do not absorb light.

[0133] The above alkali metal cation may be, for example, at least one selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium.

[0134] The above quaternary ammonium cation may be an ammonium cation in which nitrogen (N) is substituted with four substituents, a cyclic ammonium cation in which two substituents substituted on nitrogen are linked to each other, or a mixture thereof.

[0135] The above nitrogen-containing heterocyclic cation may be a heteroaromatic cyclic cation containing one or more nitrogens. Examples of such heteroaromatic cyclic cations include cations of pyrrole, pyrazole, imidazole, or pyridine, and the hydrogens of these may be substituted or unsubstituted.

[0136] Specifically, the quaternary ammonium cation may include a cation represented by the following chemical formula 4-3.

[0137] [Chemical Formula 4-3]

[0138] NY 1 Y 2 Y 3 Y 4

[0139] In the above chemical formula 4-3, Y 1 Inland Y 4 The two substituents may or may not be linked to each other to form an aliphatic ring having 4 to 10 carbon atoms,

[0140] Y that does not form an aliphatic ring 1 Inland Y 4are each independently an alkyl group having 1 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 6 to 40 carbon atoms, or an alkyl group having 2 to 40 carbon atoms connected via an ester bond (e.g., -CH2CH2-O-CO-CH2CH2CH3, etc.).

[0141] Y 1 Inland Y 4 Those in which all are methyl groups or in which two or more substituents are alkyl groups having 16 or more carbon atoms are excluded.

[0142] In the above chemical formula 4-3, Y 1 Inland Y 4 If all of the substituents are methyl groups, or if two or more substituents are alkyl groups having 16 or more carbon atoms, the electron donor may not dissolve well in the photopolymer composition, and thus the desired optical recording properties may not be exhibited.

[0143] Specifically, Y 1 Inland Y 4 The two substituents can be linked to each other to form piperidine or pyrrolidine.

[0144] Above Y 1 Inland Y 4 The substituents that do not form a central aliphatic ring may each independently be a straight-chain alkyl group having 1 to 32 carbon atoms, a phenyl group, a benzyl group, or -CH2CH2-O-CO-CH2CH2CH3. More specifically, the Y 1 Inland Y 4 The substituents that do not form a central aliphatic ring may each independently be a methyl group, a butyl group, a hexadecyl group, a hentriacontyl group, a phenyl group, or a benzyl group.

[0145] Meanwhile, the nitrogen-containing heterocyclic cation may include a cation represented by the following chemical formula 4-4.

[0146] [Chemical Formula 4-4]

[0147]

[0148] In the above chemical formula 4-4, R 107 , R 109 and R 110 are each independently hydrogen, an alkyl group having 1 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 6 to 40 carbon atoms, or an alkyl group having 2 to 40 carbon atoms connected via an ester bond (e.g., -CH2CH2-O-CO-CH2CH2CH3, etc.),

[0149] R 108 and R 111 are each independently an alkyl group having 1 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 6 to 40 carbon atoms, or an alkyl group having 2 to 40 carbon atoms connected via an ester bond (e.g., -CH2CH2-O-CO-CH2CH2CH3, etc.).

[0150] Specifically, R 107 , R 109 and R 110 For example, each independently may be hydrogen or an aryl group having 6 to 30 carbon atoms. More specifically, R 107 , R 109 and R 110 For example, each can independently be a hydrogen or a phenyl group.

[0151] Specifically, the above R 108 and R 111 Silver may be, for example, a straight-chain alkyl group having 1 to 40 carbon atoms or an arylalkyl group having 6 to 40 carbon atoms. More specifically, the R 108 and R 111 For example, it can be a hexadecyl group or a benzyl group.

[0152] The cation combined with the borate anion may include at least one selected from the group consisting of a tetrabutyl ammonium cation, a hexadecyl dimethyl benzyl ammonium cation, a hentriacontyl dimethyl benzyl ammonium cation, a hexadecyl benzyl piperidinium cation, a hexadecyl benzyl pyrrolidinium cation, a 1-hexadecyl-3-benzylimidazolium cation, and a 1,3-dihexadecyl-2-phenylimidazolium cation, as represented by the chemical formulae 4-3 and 4-4.

[0153] However, the cations combined with the borate anion are not limited to the cations described above, and even if they exhibit poor solubility when included alone, some of the cations described above may be substituted with other cations known in the relevant technical field as long as they can exhibit appropriate solubility when mixed with the cations described above. As a non-limiting example, some of the cations described above may be substituted with 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium, etc.

[0154] For example, the photopolymer composition may include an electron acceptor as a public agent. The electron acceptor may include, for example, an onium salt such as a sulfonium salt or an iodonium salt; a triazine compound such as a tris(trihalomethyl)triazine or a substituted bis(trihalomethyl)triazine; or a mixture thereof.

[0155] Specifically, the electron acceptor may include (4-(octyloxy)phenyl)(phenyl)iodonium salt as an iodonium salt, or 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine as a triazine compound. For example, commercially available H-Nu 254 (Spectra) or 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (TCI) can be used as the electron acceptor.

[0156] The photopolymer composition may contain the public domain in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the polymer matrix. Specifically, the lower limit of the content of the public domain may be, for example, 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 6 parts by weight or more, or 7 parts by weight or more, and the upper limit may be, for example, 30 parts by weight or less. When the above range is satisfied, it is advantageous to secure the desired optical recording characteristics by exhibiting an appropriate polymerization reaction rate.

[0157] For example, the photopolymer composition according to the above embodiment is a compound including a core represented by the above chemical formula 1, which is a photosensitive dye, and the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 The thermal stability of a holographic recording medium can be further improved by controlling the mixing ratio of the borate anion represented by the above chemical formulas 4-1 and 4-2, which is a phosphorus compound and an electron donor. Specifically, by controlling the mixing ratio of the specific photosensitive dye and the specific electron donor, the thermal stability of the holographic recording medium before recording can be significantly improved.

[0158] For example, a compound including a core represented by the above chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2By mixing 0.1 to 10 moles of the borate anion represented by the chemical formulas 4-1 and 4-2 with respect to 1 mole of the compound, the thermal stability of the hologram recording medium before recording can be significantly improved.

[0159] Specifically, a compound comprising a core represented by the above chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 For 1 mole of the compound, the borate anion represented by the chemical formula 4-1 and chemical formula 4-2 can be mixed in an amount of 0.1 mole or more, 0.5 mole or more, 1 mole or more, or 2 moles or more, and 10 moles or less, 8 moles or less, 7 moles or less, 6 moles or less, or 5 moles or less.

[0160] The photopolymer composition according to the above embodiment may include an additional photoinitiator to remove the color of the photosensitive dye after light irradiation for recording and to react all unreacted photoreactive monomers. As the photoinitiator, for example, an acetophenone-based compound, an oxime-based compound, a phosphine oxide-based compound, a thioxanthone-based compound, a benzoic acid ester-based compound, an imidazole-based compound, an N-aryl glycine derivative, an organic azide compound, a titanocene, an aluminate complex, an organic peroxide, an N-alkoxy pyridinium salt, an amine derivative, a diazonium salt, a sulfonium salt, an iodonium salt, a sulfonic acid ester, an imide sulfonate, a dialkyl-4-hydroxy sulfonium salt, an aryl sulfonic acid-p-nitro benzyl ester, a silanol-aluminum complex, (η6-benzene) (η5-cyclopentadienyl)iron (II), benzoin tosylate, 2,5-dinitro benzyl tosylate, N-tosylphthalic acid imide, or a mixture thereof may be used.

[0161] More specifically, the photoinitiator includes 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one (Irgacure 369), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime) (Irgacure OXE02, BASF), [(Z)-(1-oxo-1-phenylpropan-2-ylidene)amino] benzoate (TPI-057 or TPI-059 manufactured by TREEEL), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure TPO), Bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide (Irgacure 1700), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), 2,4-diethyl thioxanthone, 2-chlorothioxanthone, isopropyl thioxanthone, diisopropyl thioxanthone, ethyl 4-(dimethylamino)benzoate, 1,3-di(t-butyldioxycarbonyl)benzophenone, 3,3',4,4''-tetrakis(t-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isoxazoline, 2-mercaptobenzimidazole, Examples include, but are not limited to, bis(2,4,5-triphenyl)imidazole, 2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure 651), 1-hydroxy-cyclohexyl-phenylketone (Irgacure 184), bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium (Irgacure 784), Ebecryl P-115 (SK entis), Cyracure UVI-6970, Cyracure UVI-6974, Cyracure UVI-6990 (Dow Chemical Co. in USA), Irgacure 264, Irgacure 250 (BASF), CIT-1682 (Nippon Soda), or mixtures thereof. no.

[0162] For example, the photoinitiator may include a phosphine oxide compound.

[0163] A compound comprising a core represented by the above chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 As the content of the compound increases, the thermal stability of the holographic recording medium prior to recording can be improved. However, as the content of the compound increases, the color difference (△E) of the holographic recording medium increases, which may cause a problem in that it is difficult to exhibit colorless and transparent optical characteristics.

[0164] The above phosphine oxide compound is a photoinitiator that can sufficiently lower the increased △E due to the compound, and when the above phosphine oxide compound is used, the compound can be increased to a level that exhibits excellent thermal stability.

[0165] As the above phosphine oxide compound, for example, at least one selected from the group consisting of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure TPO), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide (Irgacure 1700), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819) may be used.

[0166] The photopolymer composition of the above embodiment may contain 0.1 to 10 parts by weight of the photoinitiator based on 100 parts by weight of the polymer matrix. Specifically, the lower limit of the content of the photoinitiator may be, for example, 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, or 1.0 parts by weight or more, and the upper limit may be, for example, 10 parts by weight or less, 8 parts by weight or less, or 5 parts by weight or less.

[0167] When the above range is satisfied, after recording optical information on the photopolymer layer, the reaction of the photoreactive monomer can be effectively terminated and the color of the photosensitive dye can be bleached, thereby providing a transparent holographic recording medium.

[0168] The photopolymer composition of the above embodiment may further include a plasticizer. The plasticizer facilitates refractive index modulation during the manufacture of a holographic recording medium. More specifically, the plasticizer lowers the glass transition temperature of the polymer matrix, thereby improving the fluidity of the photoreactive monomer. Furthermore, the plasticizer has low refractive index and non-reactivity properties, and is uniformly distributed within the polymer matrix. When the non-photopolymerized photoreactive monomer moves, the plasticizer may move in the opposite direction, thereby contributing to refractive index modulation. In addition, the plasticizer may also contribute to improving the formability of the photopolymer composition.

[0169] The plasticizer may have a low refractive index of 1.45 or less to perform the above-described function. Specifically, the upper limit of the refractive index may be, for example, 1.44 or less, 1.43 or less, 1.42 or less, 1.41 or less, 1.40 or less, 1.39 or less, 1.38 or less, or 1.37 or less, and the lower limit of the refractive index may be, for example, 1.30 or more, 1.31 or more, 1.32 or more, 1.33 or more, 1.34 or more, or 1.35 or more. Since a plasticizer having a lower refractive index than the photoreactive monomer described above is used, the refractive index of the polymer matrix can be further lowered, and the refractive index modulation with the photoreactive monomer can be further increased.

[0170] The photopolymer composition of the above embodiment may include a plasticizer, for example, a fluorine-based compound.

[0171] For example, the plasticizer may include a fluorine-based compound represented by the following chemical formula 5-1.

[0172] [Chemical Formula 5-1]

[0173]

[0174] In the above chemical formula 5-1,

[0175] Z a1 is -O- or -NH-,

[0176] Z a2 is a single bond, -O- or -NH-,

[0177] L a1 is a single bond or a 2- to 6-valent organic group in which a hydroxyl group is removed from a polyol having 2 to 6 alcohol groups,

[0178] na and ma are each independently integers from 1 to 5, and the sum of na and ma is from 2 to 6,

[0179] R a1 , R a2 and R a3 are each independently a methyl group or an ethyl group,

[0180] R a4 is a fluorine-containing substituent, which is an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines.

[0181] In the above chemical formula 5-1, L a1 A moiety containing a carbonyl group and R a4 Connect the parts that include . Therefore, the sum of na and ma is 2 to 6, L a1 It is equal to the combination number of .

[0182] For example, in the chemical formula 5-1, L a1 may be a single bond. In the above chemical formula 5-1, L a1 In this single bond case, na and ma are each 1, and Z a2 It may also be a single bond. In this case, the fluorine compound represented by the above chemical formula 5-1 may be represented by the following chemical formula 5-1-a.

[0183] [Chemical Formula 5-1-a]

[0184]

[0185] In the above chemical formula 5-1-a,

[0186] Z a1' , R a1' , R a2' , R a3' and R a4' are respectively Z of the above chemical formula 5-1 a1 , R a1 , R a2 , R a3 and R a4 Same as above Z a1' , R a1' , R a2' , R a3' and R a4' In this specification, Z of the chemical formula 5-1 a1 , R a1 , R a2 , R a3 and R a4 These may be substituents described as specific examples.

[0187] As another example, in the chemical formula 5-1, L a1 The hydroxyl group of the polyol having 2 to 6 alcohol groups is Z a1 and Z a2 It can be a 2 to 6-valent organic group in which the hydroxyl group is removed from the polyol by substitution. As an example, glycerol having three alcohol groups A trivalent organic group from which the hydroxyl group has been removed is It is displayed as follows.

[0188] In the above chemical formula 5-1, the L a1For example, it may be a divalent organic group in which a hydroxy group is removed from a diol such as ethanediol, propanediol or butanediol; a trivalent organic group in which a hydroxy group is removed from a triol such as glycerol or trimethylolpropane; a tetravalent organic group in which a hydroxy group is removed from a tetraol such as pentaerythritol or ditrimethylolpropane; a pentavalent organic group in which a hydroxy group is removed from a pentaol such as 6-methylheptanepentaol; or a hexavalent organic group in which a hydroxy group is removed from a hexaol such as dipentaerythritol.

[0189] In the above chemical formula 5-1, L a1 If this is a single bond or a divalent organic group, na and ma are each 1. If the above L a1 In the case of an organic group of 3 to 6, na may be greater than ma. For example, na may be an integer from 1 to 3, and ma may be an integer of 1.

[0190] For example, the above L a1 It can be a trivalent organic group in the form of glycerol, which is a triol, with the hydroxyl group removed. In addition, na can be 2 and ma can be 1. In this case, the fluorine-containing compound represented by the chemical formula 5-1 can be represented by the following chemical formula 5-1-b.

[0191] [Chemical Formula 5-1-b]

[0192]

[0193] In the above chemical formula 5-1-b,

[0194] Z a1" , Z a2" , R a1" , R a2" , R a3" and R a4" are respectively Z of the above chemical formula 5-1 a1 , Z a2 , R a1 , R a2 , R a3 and R a4 Same as above Z a1" , Z a2", R a1" , R a2" , R a3" and R a4" In this specification, Z of the chemical formula 5-1 a1 , Z a2 , R a1 , R a2 , R a3 and R a4 These may be substituents described as specific examples.

[0195] In the above chemical formula 5-1, the fluorine-containing substituent may be an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines. Specifically, the fluorine-containing substituent may be a straight-chain alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines. More specifically, the fluorine-containing substituent may be -(CH2) a (CF2) b CHF2 or -(CH2) a (CF2) b It can be CF3. Here, a is an integer from 0 to 3, an integer from 0 to 2, or an integer of 1, and b can be an integer from 0 to 19, an integer from 0 to 15, an integer from 0 to 12, an integer from 0 to 11, an integer from 0 to 10, or an integer from 0 to 9.

[0196] Meanwhile, as another example, the plasticizer may include a fluorine-based compound represented by the following chemical formula 5-2.

[0197] [Chemical Formula 5-2]

[0198]

[0199] In the above chemical formula 5-2,

[0200] Z b1 is -O- or -NH-,

[0201] Z b2 is a single bond, -O- or -NH-,

[0202] L b1 is a single bond or a 2- to 6-valent organic group in which a hydroxyl group is removed from a polyol having 2 to 6 alcohol groups,

[0203] nb and mb are each independently integers from 1 to 5, and the sum of nb and mb is from 2 to 6,

[0204] R b1 is a methyl group or an ethyl group,

[0205] R b2 Inland R b4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines,

[0206] R b2 and R b3 If each of the substituents is not a fluorine-containing substituent, each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-,

[0207] R b4 If it is not a fluorine-containing substituent, it is an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-.

[0208] In the above chemical formula 5-2, L b1A moiety containing a carbonyl group and R b4 Connect the part containing . Therefore, the sum of nb and mb is 2 to 6, L b1 It is equal to the combination number of .

[0209] For example, in the chemical formula 5-2, L b1 may be a single bond. In the above chemical formula 5-2, L b1 In this single bond case, nb and mb are each 1, and Z b2 It may also be a single bond. In this case, the fluorine compound represented by the above chemical formula 5-2 may be represented by the following chemical formula 5-2-a.

[0210] [Chemical Formula 5-2-a]

[0211]

[0212] In the above chemical formula 5-2-a,

[0213] Z b1' , R b1' , R b2' , R b3' and R b4' are respectively Z of the above chemical formula 5-2 b1 , R b1 , R b2 , R b3 and R b4 Same as above Z b1' , R b1' , R b2' , R b3' and R b4' In this specification, Z of the chemical formula 5-2 b1 , R b1 , R b2 , R b3 and R b4 These may be substituents described as specific examples.

[0214] As another example, in the chemical formula 5-2, L b1 The hydroxyl group of the polyol having 2 to 6 alcohol groups is Z b1 and Z b2It may be a 2-6 valent organic group in which the hydroxyl group is removed from the polyol by substitution.

[0215] In the above chemical formula 5-2, the L b1 For example, it may be a divalent organic group in which a hydroxy group is removed from a diol such as ethanediol, propanediol or butanediol; a trivalent organic group in which a hydroxy group is removed from a triol such as glycerol or trimethylolpropane; a tetravalent organic group in which a hydroxy group is removed from a tetraol such as pentaerythritol or ditrimethylolpropane; a pentavalent organic group in which a hydroxy group is removed from a pentaol such as 6-methylheptanepentaol; or a hexavalent organic group in which a hydroxy group is removed from a hexaol such as dipentaerythritol.

[0216] In the above chemical formula 5-2, L b1 If this is a single bond or a divalent organic group, nb and mb are each 1. If the above L b1 In the case of an organic group of 3 to 6, nb may be greater than mb. For example, nb may be an integer from 1 to 3, and mb may be an integer of 1.

[0217] For example, the above L b1 It can be a trivalent organic group in the form of glycerol in which a hydroxyl group is removed. In addition, nb can be 2 and mb can be 1. In this case, the fluorine-containing compound represented by the chemical formula 5-2 can be represented by the following chemical formula 5-2-b.

[0218] [Chemical Formula 5-2-b]

[0219]

[0220] In the above chemical formula 5-2-b,

[0221] Z b1" , Z b2" , R b1" , R b2" , R b3" and R b4" are respectively Z of the above chemical formula 5-2 b1 , Z b2, R b1 , R b2 , R b3 and R b4 Same as above Z b1" , Z b2" , R b1" , R b2" , R b3" and R b4" In this specification, Z of the chemical formula 5-2 b1 , Z b2 , R b1 , R b2 , R b3 and R b4 These may be substituents described as specific examples.

[0222] In the above chemical formula 5-2, R b2 Inland R b4 At least one of the fluorine-containing substituents is a fluorine-containing substituent. The fluorine-containing substituent may be an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines. Specifically, the fluorine-containing substituent may be a straight-chain alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines. More specifically, the fluorine-containing substituent may be -(CH2) a (CF2) b CHF2 or -(CH2) a (CF2) b It can be CF3. Here, a is an integer from 0 to 3, an integer from 0 to 2, or an integer of 1, and b can be an integer from 0 to 19, an integer from 0 to 15, an integer from 0 to 12, an integer from 0 to 11, an integer from 0 to 10, or an integer from 0 to 9.

[0223] In the above chemical formula 5-2, R b2 and R b3 If R is not a fluorine-containing substituent, b2 and R b3are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituents is replaced with -O-, -S-, or -NH-.

[0224] Specifically, in the chemical formula 5-2, R b2 and R b3 If R is not a fluorine-containing substituent, b2 and R b3 are each independently hydrogen, a straight-chain alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a heterocycloalkyl group having 4 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, or -(R 5 -O) p -R 6 It can be. The above -(R 5 -O) p -R 6 In R 5 is an alkylene group having 1 to 6 carbon atoms, and R 6 is an alkyl group having 1 to 6 carbon atoms, and p can be an integer from 1 to 12.

[0225] More specifically, in the chemical formula 5-2, R b2 and R b3 If R is not a fluorine-containing substituent, b2 and R b3 are each independently hydrogen, methyl, ethyl, propyl, butyl, cyclohexyl, tetrahydropyranyl, phenyl or -(R 5 -O) p -R 6 It can be. Here, the R 5R may be a methylene group, an ethylene group, an n-propylene group or an n-butylene group, and among these, it may be a methylene group or an ethylene group. 6 may be a methyl group, an ethyl group, an n-propyl group, or an n-butyl group, and among these, may be a methyl group. The p may be, for example, an integer from 1 to 12, an integer from 1 to 10, an integer from 1 to 8, an integer from 1 to 6, an integer from 1 to 5, an integer from 1 to 4, or an integer from 1 to 3.

[0226] In the above chemical formula 5-2, R b4 If R is not a fluorine-containing substituent, b4 is an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-.

[0227] Specifically, in the chemical formula 5-2, R b4 If R is not a fluorine-containing substituent, b4 is a straight chain alkyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, or -(R 5 -O) p -R 6 It can be. The above -(R 5 -O) p -R 6 In R 5 is an alkylene group having 1 to 6 carbon atoms, and R 6 is an alkyl group having 1 to 6 carbon atoms, and p can be an integer from 1 to 12.

[0228] More specifically, in the chemical formula 5-2, R b4 If R is not a fluorine-containing substituent, b4 is -(R 5 -O) p-R 6 It can be. Here, the R 5 R may be a methylene group, an ethylene group, an n-propylene group or an n-butylene group, and among these, it may be a methylene group or an ethylene group. 6 may be a methyl group, an ethyl group, an n-propyl group, or an n-butyl group, and among these, may be a methyl group. The p may be, for example, an integer from 1 to 12, an integer from 1 to 10, an integer from 1 to 8, an integer from 1 to 6, an integer from 1 to 5, an integer from 1 to 4, or an integer from 1 to 3.

[0229] Meanwhile, as another example, the plasticizer may include a fluorine-based compound represented by the following chemical formula 5-3.

[0230] [Chemical Formula 5-3]

[0231]

[0232] In the above chemical formula 5-3,

[0233] Z c1 and Z c2 are each independently -O-, -S- or -NH-,

[0234] R c1 Inland R c4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines,

[0235] R c1 Inland R c4When the substituents are not fluorine-containing, each independently represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the substituents is replaced with -O-, -S-, or -NH-.

[0236] In the above chemical formula 5-3, R c1 Inland R c4 At least one of which is a fluorine-containing substituent. For example, the R c1 may be a fluorine-containing substituent.

[0237] The fluorine-containing substituent may be an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines.

[0238] Specifically, the fluorine-containing substituent may be a straight-chain alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 12 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 14 carbon atoms substituted with two or more fluorines.

[0239] More specifically, the fluorine-containing substituent is -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b CF3, a decafluorocyclohexyl group, or a pentafluorophenyl group. Here, a is an integer from 0 to 3, an integer from 0 to 2, or an integer from 0 to 1, and b is an integer from 0 to 19, an integer from 0 to 15, an integer from 0 to 14, an integer from 0 to 13, an integer from 0 to 12, or an integer from 0 to 11.

[0240] For example, the fluorine-containing substituent is -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b In the case of CF3 or decafluorocyclohexyl group, it is possible to provide a holographic recording medium with low haze while contributing to greatly modulating the refractive index.

[0241] In the above chemical formula 5-3, R c1 Inland R c4 If R is not a fluorine-containing substituent, c1 Inland R c4 are each independently an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-.

[0242] Specifically, in the above chemical formula 5-3, R c1 Inland R c4 If R is not a fluorine-containing substituent, c1 Inland R c4 are each independently a straight chain alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a heterocycloalkyl group having 4 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, a heteroaryl group having 4 to 12 carbon atoms, an arylalkyl group having 7 to 16 carbon atoms, or -(R 5 -Y 1 ) c -R 6 It can be. The above -(R 5 -Y 1 ) c -R 6 In R 5 is an alkylene group having 1 to 6 carbon atoms, and R 6is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms, and Y 1 is -O- or -S-, c can be an integer from 1 to 12, and when c is 2 or greater, R 5 may be identical or different.

[0243] More specifically, in the chemical formula 5-3, R c1 Inland R c4 If R is not a fluorine-containing substituent, c1 Inland R c4 are each independently an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a phenyl group, a benzyl group, a pyridinyl group, a pyrimidinyl group, a methoxymethyl group, a methoxyethyl group, a methylmercaptoethyl group, a methylaminoethyl group, -(CH2CH2O) d1 CH3, -CH2O(CH2CH2O) d2 CH3, cyclohexyloxyethyl group, cyclohexylmercaptoethyl group or phenyloxyethyl group. Here, d1 is an integer from 1 to 5, and d2 is an integer from 1 to 4.

[0244] The photopolymer composition according to the above embodiment may include at least one or a combination of two or more fluorine-based compounds represented by Chemical Formulas 5-1 to 5-3 as the plasticizer.

[0245] The photopolymer composition of the above embodiment may contain 20 to 200 parts by weight of the plasticizer based on 100 parts by weight of the polymer matrix. Specifically, the lower limit of the plasticizer content may be, for example, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, or 55 parts by weight or more, and the upper limit may be, for example, 200 parts by weight or less, 180 parts by weight or less, 150 parts by weight or less, 140 parts by weight or less, or 130 parts by weight or less. When the above range is satisfied, the photopolymer composition may exhibit a large refractive index modulation value after recording due to the plasticizer having a sufficiently low refractive index without problems such as poor compatibility with components included in the photopolymer composition, resulting in poor haze or other problems such as some of the plasticizer being eluted to the surface of the photopolymer layer, thereby advantageously securing excellent optical recording characteristics.

[0246] The photopolymer composition of the above embodiment may additionally include an additive such as a surfactant or an antifoaming agent.

[0247] The above photopolymer composition may include a silicone-based surfactant, a fluorine-based surfactant, or a mixture thereof as a surfactant.

[0248] Examples of the silicone surfactants include BYK-077, BYK-085, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-310, BYK-320, BYK-322, BYK-323, BYK-325, BYK-330, BYK-331, BYK-333, BYK-335, BYK-341v344, BYK-345v346, BYK-348, BYK-354, BYK355, BYK-356, BYK-358, BYK-361, BYK-370, BYK-371, BYK-375 from BYK Chemie. BYK-380, BYK-390, BYK-3550, etc. can be used. The above fluorinated surfactants include F-114, F-177, F-410, F-411, F-450, F-493, F-494, F-443, F-444, F-445, F-446, F-470, F-471, F-472SF, F-474, F-475, F-477, F-478, F-479, F-480SF, F-482, F-483, F-484, F-486, F-487, F-172D, MCF-350SF, TF-1025SF, TF-1117SF, TF-1026SF, TF-1128, TF-1127, TF1129, manufactured by DIC (DaiNippon Ink & Chemicals). TF-1126, TF-1130, TF-1116SF, TF-1131, TF1132, TF1027SF, TF-1441, TF-1442, etc. can be used.

[0249] If the photopolymer composition of the above embodiment includes a surfactant, the surfactant may be included in an amount of 0.01 parts by weight or more, 0.02 parts by weight or more, 0.03 parts by weight or more, or 0.05 parts by weight or more, but 5 parts by weight or less, or 3 parts by weight or less, based on 100 parts by weight of the polymer matrix. When the above range is satisfied, excellent adhesiveness and releasability can be imparted to the photopolymer layer, thereby preserving excellent optical recording characteristics.

[0250] The photopolymer composition of the above embodiment may include a silicone-based reactive additive as a defoaming agent. Commercially available products such as Tego Rad 2500 may be used as the silicone-based reactive additive. The content of the defoaming agent may be appropriately adjusted so as not to impede the function of the holographic recording medium.

[0251] The photopolymer composition of the above embodiment may additionally include a solvent.

[0252] The solvent may be an organic solvent, and for example, may be at least one organic solvent selected from the group consisting of ketones, alcohols, acetates, and ethers, but is not limited thereto. Specific examples of such organic solvents include at least one selected from the group consisting of ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, or isobutyl ketone; alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, or t-butanol; acetates such as ethyl acetate, i-propyl acetate, or polyethylene glycol monomethyl ether acetate; and ethers such as tetrahydrofuran or propylene glycol monomethyl ether.

[0253] The organic solvent may be added at the time when each component included in the photopolymer composition is mixed, or may be included in the photopolymer composition while each component is added in a dispersed or mixed state in the organic solvent.

[0254] The photopolymer composition of the above embodiment may include a solvent so that the solid concentration is 1 to 90 wt%. Specifically, the photopolymer composition may include a solvent so that the solid concentration is 20 wt% or more or 30 wt% or more, and 85 wt% or less, 80 wt% or less, 75 wt% or less, or 70 wt% or less. Within this range, the photopolymer composition exhibits appropriate flowability and can form a coating film without defects such as stripes, and no defects occur during the drying and curing processes thereof, so that a photopolymer layer exhibiting desired physical properties and surface characteristics can be formed.

[0255] Meanwhile, according to another embodiment of the invention, a photopolymer composition is provided, which comprises a polymer matrix or a precursor thereof; a photoreactive monomer; a photosensitive dye; and a co-initiator, wherein the photosensitive dye comprises a compound represented by the following chemical formula 1-1.

[0256] [Chemical Formula 1-1]

[0257]

[0258] In the above chemical formula 1-1,

[0259] R 1 is an alkylene group having 1 to 6 carbon atoms, and R 2 is an alkyl group having 1 to 6 carbon atoms,

[0260] n1 is an integer from 1 to 6,

[0261] R 3 is an alkyl group having 3 to 12 carbon atoms,

[0262] R 4 is hydrogen or an alkyl group having 1 to 6 carbon atoms,

[0263] R 5 and R 6 are each independently a halogen, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

[0264] n2 and n3 are each independently integers from 0 to 4,

[0265] Z is oxygen, sulfur or CR 7 R 8 And,

[0266] R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

[0267] The photopolymer composition of another embodiment of the above is a compound including a core represented by the chemical formula 1, and the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 It may include the same composition as the photopolymer composition of the above embodiment, except that it includes a compound represented by the above chemical formula 1-1 instead of the phosphorus compound.

[0268] The polymer matrix or precursor thereof, the photoreactive monomer, the photosensitive dye including the compound represented by the chemical formula 1-1, and the co-initiator included in the photopolymer composition of the other embodiment of the above have been described in detail above, so a detailed description thereof is omitted here, and the photopolymer composition of the other embodiment of the above may include all other optional component(s) included in the photopolymer composition of the other embodiment of the above.

[0269] Meanwhile, according to another embodiment of the invention, a holographic recording medium is provided comprising a photopolymer layer formed from the photopolymer composition.

[0270] The above photopolymer composition may be a photopolymer composition of the above-described embodiment or another embodiment, and since the components thereof have been described in detail above, a detailed description thereof is omitted here.

[0271] The holographic recording medium of another embodiment of the above may further include a substrate on at least one surface of the photopolymer layer. The type of substrate is not particularly limited, and any substrate known in the relevant technical field may be used. For example, substrates such as glass, PET (polyethylene terephthalate), TAC (triacetyl cellulose), PC (polycarbonate), and COP (cycloolefin polymer) may be used.

[0272] The above photopolymer layer is formed from the photopolymer composition, and thus, despite its thin thickness, it exhibits a large refractive index modulation value and high diffraction efficiency, thereby ensuring excellent optical recording characteristics, and can exhibit excellent reliability even in a high-temperature environment.

[0273] The thickness of the photopolymer layer may be, for example, in the range of 5.0 to 40.0 μm. Specifically, the lower limit of the thickness of the photopolymer layer may be, for example, 6 μm or more, 7 μm or more, 8 μm or more, or 9 μm or more. And, the upper limit of the thickness may be, for example, 35 μm or less, 30 μm or less, 29 μm or less, 28 μm or less, 27 μm or less, 26 μm or less, 25 μm or less, 24 μm or less, 23 μm or less, 22 μm or less, 21 μm or less, 20 μm or less, 19 μm or less, or 18 μm or less.

[0274] The holographic recording medium of another embodiment of the present invention can implement a refractive index modulation value (△n) of 0.020 or more, 0.025 or more, 0.026 or more, 0.027 or more, 0.028 or more, 0.029 or more, 0.030 or more, 0.031 or more, 0.032 or more, 0.033 or more, 0.034 or more, or 0.035 or more, even though the thickness of the photopolymer layer is as thin as 5 to 30 ㎛. The upper limit of the refractive index modulation value is not particularly limited, but may be, for example, 0.060 or less.

[0275] The hologram recording medium of another embodiment of the above is not limited thereto, but may be one on which a reflective hologram or a transmissive hologram is recorded.

[0276] The above holographic recording medium may have a notch filter structure in relation to the diffraction grating structure. That the holographic recording medium of another embodiment has a notch filter structure may mean, for example, that the diffraction grating is not inclined (non-slanted) (substantially 0°) with respect to the substrate plane, such as that the diffraction grating is parallel to the substrate plane. Such a holographic recording medium may have a structure in which two layers having different refractive indices (e.g., a high refractive index layer and a low refractive index layer) are alternately repeated. In addition, the two repeated layers may each have a predetermined thickness that is the same or different from each other. Such a non-slanted diffraction grating recording can be manufactured in a manner in which the incident angles of the object light and the reference light are the same with respect to the normal. In a non-slanted structure, the degree of deformation (e.g., shrinkage or expansion) under high temperature and high humidity conditions is more clearly confirmed than in a slanted structure, and the recording medium may be less affected by shrinkage and expansion of the substrate.

[0277] The hologram recording medium of another embodiment of the present invention may have high diffraction efficiency. For example, the hologram recording medium may have a diffraction efficiency of 70% or more when recording a notch filter hologram. At this time, the thickness of the photopolymer layer may be, for example, 5 to 30 μm. Specifically, when recording the notch filter hologram, the diffraction efficiency may be 71% or more, 75% or more, 80% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, or 94% or more. In this way, the hologram recording medium of another embodiment of the present invention may achieve excellent diffraction efficiency even if it includes a thin photopolymer layer. The diffraction efficiency may be measured by the method described in the test examples described below.

[0278] According to another embodiment of the present invention, a holographic recording medium is a compound including a core represented by the chemical formula 1 as a photosensitive dye, and the openness of a double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 By including a compound (or a compound represented by the above chemical formula 1-1), optical recording in the blue region is possible and excellent thermal stability can be exhibited. In particular, the holographic recording medium according to another embodiment of the present invention has excellent thermal stability before recording, so that optical recording characteristics can be maintained at an excellent level even when exposed to high temperatures before recording.

[0279] For example, the hologram recording medium of another embodiment may have a diffraction efficiency retention rate after high temperature retention of 90% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more when a notch filter hologram is recorded after being left at a high temperature of 60° C. for 20 days before recording. The diffraction efficiency retention rate after high temperature retention refers to the percentage of the diffraction efficiency measured by recording a notch filter hologram on a hologram recording medium before recording that has not been exposed to high temperature to the initial diffraction efficiency measured by recording a notch filter hologram on a hologram recording medium before recording that has not been exposed to high temperature. The diffraction efficiency retention rate after high temperature retention can be measured by the method described in the test examples described below.

[0280] Since the diffraction efficiency after high-temperature storage may be higher than the diffraction efficiency before high-temperature protection, the upper limit of the diffraction efficiency retention rate may exceed 100%. The upper limit of the diffraction efficiency retention rate is not particularly limited, but may be, for example, 110% or less, 105% or less, or 102% or less.

[0281] As another example, the hologram recording medium of the above another embodiment may have a diffraction efficiency retention rate of 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, or 95% or more when a notch filter hologram is recorded after being stored at a high temperature of 60°C for 30 days before recording. The upper limit of the diffraction efficiency retention rate after being stored at 60°C for 30 days is not particularly limited, but may be, for example, 105% or less or 102% or less.

[0282] Previously developed holographic recording media capable of optical recording in the blue region had the problem of exhibiting opaque colors compared to holographic recording media capable of optical recording in the red or green region. In other words, holographic recording media capable of optical recording in the blue region exhibited high color difference (△E).

[0283] However, the holographic recording medium of another embodiment of the present invention is a compound including a core represented by the chemical formula 1, wherein the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 By including the compound (or the compound represented by the above chemical formula 1-1), it is possible to exhibit colorless and transparent optical properties while enabling optical recording in the blue region.

[0284] For example, a holographic recording medium that has been photobleached without recording optical information may have a color difference (△E) of 3.0 or less compared to white light having the same brightness. The △E can be obtained by referring to the measurement method described in detail in the test examples described below. A low △E means that the color of the image visible through the holographic recording medium has a small difference from the actual color (originally intended color) because the three primary lights of red, green, and blue uniformly pass through the holographic recording medium without being biased to any one side.

[0285] The △E value of the holographic recording medium of the above another embodiment may be, for example, 3.0 or less, 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, 2.5 or less, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, or 1.9 or less. The lower limit of the △E value is not particularly limited and may be 0 or more.

[0286] The holographic recording medium of another embodiment can exhibit colorless and transparent optical characteristics by removing the color of the photosensitive dye through a photobleaching step after recording optical information. Accordingly, the holographic recording medium of another embodiment can exhibit high transmittance in the blue wavelength region after optical information is recorded. For example, the holographic recording medium of another embodiment can have an average transmittance in a region of 400 to 430 nm of 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, or 85% or more after optical information is recorded. The upper limit of the average transmittance is not particularly limited, and may be 100% or less or 95% or less. The average transmittance in the region of 400 to 430 nm is an average value obtained by measuring the transmittance in the region of 400 to 430 nm using a UV-Vis spectrometer.

[0287] The uses of the holographic recording medium of the above-described further embodiment are not particularly limited. Non-limiting examples include applications where the holographic recording medium is likely to be exposed to high-temperature environments, specifically, smart devices such as mobile devices, components of wearable displays, or automotive components (e.g., head-up displays).

[0288] Meanwhile, according to another embodiment of the invention, a method for manufacturing a holographic recording medium is provided, including a step of forming a photopolymer layer by applying a photopolymer composition.

[0289] The above photopolymer composition may be a photopolymer composition of the above-described embodiment, and since the photopolymer composition has been described in detail above, a detailed description thereof is omitted here.

[0290] In the step of forming the photopolymer layer, a photopolymer composition comprising the above-described composition may first be prepared. When preparing the photopolymer composition, a commonly known mixer, stirrer, or mixer may be used to mix each component without particular limitation. In addition, this mixing process may be performed at a temperature ranging from 0°C to 100°C, from 10°C to 80°C, or from 20°C to 60°C.

[0291] In the step of forming the above photopolymer layer, the prepared photopolymer composition may be applied to form a coating film formed from the photopolymer composition. The coating film may be dried naturally at room temperature or at a temperature in the range of 30 to 80°C. Through this process, a hydrosilylation reaction between the unreacted hydroxyl groups of the acrylic polyol and the silane functional groups of the siloxane polymer may be induced.

[0292] The photopolymer layer manufactured through the step of forming the above photopolymer layer may have a photoreactive monomer, a photosensitive dye, a public initiator, and additives added as needed uniformly dispersed within the crosslinked polymer matrix.

[0293] The method for manufacturing a holographic recording medium according to another embodiment of the present invention may include, after the step of forming a photopolymer layer, a step of irradiating a coherent laser to a predetermined area of ​​the photopolymer layer to selectively polymerize a photoreactive monomer included in the photopolymer layer to record optical information.

[0294] In the step of recording the optical information, when a coherent laser is irradiated onto the photopolymer layer, polymerization of the photoreactive monomer occurs in a region where constructive interference occurs, thereby forming a photopolymer, and polymerization of the photoreactive monomer does not occur or is suppressed in a region where destructive interference occurs, thereby forming a photoreactive monomer. In addition, the unreacted photoreactive monomer diffuses toward the photopolymer side where the concentration of the photoreactive monomer is low, thereby causing refractive index modulation, and a diffraction grating is generated by the refractive index modulation. Accordingly, a hologram, i.e., optical information, is recorded on the photopolymer layer having the diffraction grating.

[0295] The method for manufacturing a holographic recording medium of another embodiment of the present invention may further include a step of photobleaching by irradiating light to the entire photopolymer layer on which the optical information is recorded after the step of recording the optical information.

[0296] In the above-described photobleaching step, ultraviolet rays are irradiated onto the photopolymer layer on which optical information is recorded, thereby terminating the reaction of the photoreactive monomer remaining in the photopolymer layer and removing the color of the photosensitive dye. For example, in the above-described photobleaching step, ultraviolet rays (UVA) in the range of 320 to 400 nm are irradiated, thereby terminating the reaction of the photoreactive monomer and removing the color of the photosensitive dye.

[0297] Meanwhile, according to another embodiment of the invention, an optical element including the holographic recording medium is provided.

[0298] Specific examples of the optical element include smart devices such as mobile devices, components of wearable displays, automotive products (e.g., head up displays), holographic fingerprint recognition systems, holographic optical elements having the functions of optical lenses, mirrors, deflecting mirrors, filters, diffusion screens, diffractive elements, light guides, waveguides, projection screens and / or masks, media and optical diffusion plates of optical memory systems, optical wavelength splitters, reflective and transmissive color filters, etc.

[0299] An example of an optical element including the above holographic recording medium is a holographic display device. The holographic display device includes a light source unit, an input unit, an optical system, and a display unit.

[0300] Specifically, the light source unit is a unit that irradiates a laser beam used to provide, record, and reproduce three-dimensional image information of an object in the input unit and display unit.

[0301] The above input section is a section that inputs 3D image information of an object to be recorded on a display section in advance, and specifically, it is a section that can input 3D information of an object, such as the intensity and phase of light by space, into an electrically addressed liquid crystal SLM, and at this time, an input beam can be used.

[0302] The above optical system may be composed of a mirror, a polarizer, a beam splitter, a beam shutter, a lens, etc. The above optical system may distribute a laser beam emitted from a light source unit into an input beam sent to an input unit, a recording beam sent to a display unit, a reference beam, an erase beam, a readout beam, etc.

[0303] The display unit can receive three-dimensional image information of an object from an input unit, record it on a hologram plate formed of an optically addressed SLM, and reproduce a three-dimensional image of the object. At this time, the three-dimensional image information of the object can be recorded through interference between an input beam and a reference beam. The three-dimensional image information of the object recorded on the hologram plate can be reproduced as a three-dimensional image by a diffraction pattern generated by a readout beam, and an erase beam can be used to quickly remove the formed diffraction pattern. Meanwhile, the hologram plate can be moved between a position for inputting a three-dimensional image and a position for reproducing the image.

[0304] A photopolymer composition according to one embodiment of the invention can provide a holographic recording medium and an optical element including the same, which have excellent optical recording properties such as diffraction efficiency while securing colorless and transparent optical properties and excellent thermal stability.

[0305] Fig. 1 schematically illustrates a recording equipment setup for hologram recording. Specifically, Fig. 1 schematically illustrates a process in which a laser of a predetermined wavelength is irradiated from a light source (10), and then passes through a mirror (20, 20'), an iris (30), a spatial filter (40), an iris (30'), a collimation lens (50), and a splitter (PBS, Polarized Beam Splitter) (60), and is irradiated onto a PP (hologram recording medium) (80) located on one surface of a mirror (70).

[0306] The following specific examples of the invention will further illustrate its functions and effects. However, these examples are presented as illustrative examples and do not limit the scope of the invention in any way.

[0307] In the following manufacturing examples, examples, and comparative examples, the content of raw materials, etc. refers to the content based on solid content unless otherwise specified.

[0308]

[0309] Manufacturing Example 1: Manufacturing of acrylic polyol

[0310] In a 2 L jacketed reactor, 132 g of butyl acrylate, 420 g of ethyl acrylate, and 48 g of hydroxybutyl acrylate were added, and diluted with 1,200 g of ethyl acetate. The reaction temperature was set to 60 to 70 °C, and stirring was performed for about 30 minutes to 1 hour. 0.42 g of n-dodecyl mercaptan (n-DDM) was additionally added, and stirring was performed for about another 30 minutes. Thereafter, 0.24 g of AIBN, a polymerization initiator, was added, and polymerization was performed at the reaction temperature for more than 4 hours until the residual acrylate content became less than 1%, thereby producing an acrylate copolymer (weight average molecular weight of about 300,000, OH equivalent of about 1802 g / equivalent) in which the hydroxyl group was located in the branched chain.

[0311]

[0312] Example 1: Preparation of photopolymer composition and holographic recording medium

[0313] (1) Preparation of photopolymer composition

[0314] First, 1.65 g of poly(methylhydrosiloxane) (manufactured by Sigma-Aldrich, number average molecular weight: approximately 390, Si-H equivalent: approximately 103 g / equivalent) as a siloxane polymer and 33.4 g of acrylic polyol having a solid content of 30 wt% (solid content: 10.02 g) manufactured in Manufacturing Example 1 were mixed (SiH / OH molar ratio = 2.83).

[0315] And, 17.2 g of HR 6042 (Miwon, refractive index 1.60) as a photoreactive monomer and 3.3 g of O-phenylphenol (ethylene oxide) acrylate, 0.25 g of a compound represented by the following chemical formula A-1 (molecular weight: 749.86 g / mol) as a photosensitive dye, 0.5 g of tetrabutyl ammonium tri(p-chloro-o-methylphenyl)butyl borate (molecular weight: 678.12 g / mol) and 0.45 g of hexadecyl dimethyl benzyl ammonium tri(p-chlorophenyl)butyl borate (molecular weight: 763.21 g / mol) as an electron donor, 0.02 g of 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (TCI) as an electron acceptor, and 0.02 g of a photoinitiator. 0.5 g of Irgacure 819, 13.5 g of a fluorine-containing compound represented by the following chemical formula B as a plasticizer, and 0.16 g of BYK-331 as an additive were added, and a mixed solvent (weight ratio of n-butanol, i-propanol, methyl isobutyl ketone, methyl ethyl ketone, and ethyl acetate = 0.34:15.00:9.33:21.98:18.35) was added so that the solid content became 35 wt%, and then stirred with a paste mixer for about 30 minutes in a light-blocking state. Thereafter, a Karstedt (Pt series) catalyst was added for matrix crosslinking to prepare a photopolymer composition.

[0316] About 4 moles of the tetrabutyl ammonium tri(p-chloro-o-methylphenyl)butyl borate and hexadecyl dimethyl benzyl ammonium tri(p-chlorophenyl)butyl borate were used for 1 mole of the compound represented by the following chemical formula A-1.

[0317] [Chemical Formula A-1]

[0318]

[0319]

[0320] [Chemical Formula B]

[0321]

[0322]

[0323] (2) Manufacturing of holographic recording media

[0324] The above photopolymer composition was coated to a predetermined thickness on a 60 μm thick TAC substrate using a Mayer bar and dried at 80°C for 10 minutes. The thickness of the photopolymer layer after drying was approximately 14 μm.

[0325]

[0326] Example 2 and Comparative Examples 1 to 6: Preparation of photopolymer composition and holographic recording medium

[0327] A photopolymer composition and a holographic recording medium therefrom were prepared in the same manner as in Example 1, except that the photosensitive dye was changed as described in Table 1 below.

[0328]

[0329] <Calculation of openness of photosensitizing dyes>

[0330] The openness of a photosensitive dye refers to the openness of a double bond connecting two hetero rings of a core that the photosensitive dyes used in the examples and comparative examples commonly include.

[0331] The openness of the above double bond was calculated by calculating the openness for each of the two carbon atoms forming the double bond and then adding the openness values ​​of the two carbons.

[0332] The openness of the above carbon atom is the area of ​​the open surface area not covered by the substituents relative to the surface area of ​​a sphere whose radius is 1.2 Å from the carbon atom.

[0333] The above openness is obtained by using density functional theory (DFT) in Gaussian 16, a quantum chemistry calculation program manufactured by Gaussian, with B3LYP as the functional and 6-31G as the basis function. * It was obtained using Jmol software.

[0334]

[0335] Photosensitive dye openness (Å) 2 ) Example 1 [Chemical Formula A-1] (Molecular weight: 749.864 g / mol)8.41Example 2 [Chemical Formula A-2] (Molecular weight: 779.8902 g / mol)8.23Comparative Example 1 [Chemical Formula C-1] 8.75 Comparative Example 2 [Chemical Formula C-2] 12.74 Comparative Example 3 [Chemical Formula C-3] 12.52 Comparative Example 4 [Chemical Formula C-4] 4.66 Comparative Example 5 [Chemical Formula C-5] 6.73 Comparative Example 6 [Chemical Formula C-6] 6.60

[0336]

[0337] Test Example: Performance Evaluation of Holographic Recording Media

[0338] (1) Color difference (△E)

[0339] A photobleached sample was obtained by irradiating a holographic recording medium on which no optical information was recorded (hereinafter, a sample before recording) with ultraviolet (UV) light and a white LED. The transmittance of the photobleached sample in the visible light region (wavelength region of 400 to 700 nm) was measured using a UV-Vis spectrometer to obtain a transmittance spectrum. The trichromatic stimulus values ​​(X, Y, Z) of the CIE XYZ color space were calculated from the transmittance spectrum of the photobleached sample. The trichromatic stimulus values ​​were calculated using the following equation 1.

[0340] [Formula 1]

[0341]

[0342] In the above equation 1, S(λ) is the output distribution function of the standard illuminant (D65), is the color matching function for a viewing angle of 10° in the CIE XYZ color space, is the transmittance distribution function (transmittance spectrum) of the photobleached sample, and λ is the wavelength.

[0343] The trichromatic stimulus value obtained through the above equation 1 is L in the CIE Lab color space through the equation 2 below. * , a * , b * Converted to value.

[0344] [Formula 2]

[0345]

[0346] In the above equation 2, X n , Y n and Z n For a standard illuminant (D65) and a field of view of 10 °, the values ​​are 94.71, 100.00, and 107.08, respectively, and t is X / X n , Y / Y n or Z / Z n am.

[0347] L obtained through the above equation 2 * , a * , b * The color difference (△E) was obtained by substituting it into Equation 3.

[0348] [Formula 3]

[0349]

[0350] In the above equation 3, L S * , a S * and b S * is the value of the target sample for which the color difference is to be measured, and L R * , a R * and b R * is the value of the reference sample.

[0351] In this test example, the reference sample was set to have the same brightness (L) as the target sample. * ) assuming white light with L R * Silver L S * As is the same as (L) in Equation 3 S* - L R * ) 2 is 0, and a R * and b R * It is also 0.

[0352] The above low △E means that the three primary lights of red, green, and blue uniformly pass through the holographic recording medium without being biased to one side, so the color of the image seen by passing through the holographic recording medium has little difference from the actual color (originally intended color).

[0353]

[0354] (2) Diffraction efficiency (DE)

[0355] A diffraction grating was recorded using a setup similar to that in Fig. 1. Specifically, when the manufactured photopolymer layer is laminated on a mirror and then irradiated with a laser, a notch filter hologram having a periodic refractive index modulation in the thickness direction can be recorded through the interference of the incident light (L) and the light reflected from the mirror (L'). In this example, a 460 nm laser was used at an incident angle of 0 ° (degree) and 0.75 mW / cm 2 A notch filter hologram was recorded for 40 seconds at a light intensity of . The notch filter and Bragg reflector are optical elements that reflect only light of a specific wavelength, and have a structure in which two layers with different refractive indices are periodically repeatedly laminated at a constant thickness.

[0356] After recording, the diffraction efficiency (η) was calculated for the sample using Equation 4 below.

[0357] [Formula 4]

[0358] η(%) = {P D / (P D + P T )} X 100

[0359] In the above equation 4, η is the diffraction efficiency, and P Dis the output power (mW / cm2) of the diffracted beam of the sample after recording, and P T is the output power (mW / ㎠) of the beam transmitted through the sample after recording.

[0360]

[0361] (3) High temperature stability before recording

[0362] To verify the high-temperature stability of the holographic recording medium before recording, the sample was exposed to high temperature before recording, and the optical recording characteristics before and after exposure to high temperature were compared.

[0363] Specifically, the sample before recording was left at 60°C for 20 days, and then the diffraction grating was recorded using the method described above, and the diffraction efficiency was obtained using Equation 4.

[0364] Additionally, after leaving the sample at 60°C for 30 days before recording, the diffraction grating was recorded using the method described above, and the diffraction efficiency was obtained using Equation 4.

[0365] The diffraction efficiency retention rate (DE retention rate) was calculated using Equation 5 below and is shown in Table 2 below.

[0366] [Formula 5]

[0367] DE retention rate (%) = 100 X {DE b / DE a}

[0368] In the above equation 5, DE a is the diffraction efficiency of the sample before being exposed to high temperature, and is the initial diffraction efficiency measured by recording the diffraction grating on a sample that was not exposed to high temperature before recording.

[0369] DE b is the diffraction efficiency of a sample after being exposed to high temperature, and is the diffraction efficiency measured by recording the diffraction grating on a sample exposed to high temperature before recording.

[0370]

[0371] Color difference (△E) Initial DE (%) High temperature stability before recording 60 ℃ 20 days left 60 ℃ 30 days left DE (%) DE retention (%) DE (%) DE retention (%) Example 12.895.195.110090.595.2 Example 21.8794.393.799.494.8100.5 Comparative example 14.3868.238.055.731.145.6 Comparative example 23.4358.110.518.1--Comparative example 32.7155.430.154.322.540.6 Comparative example 43.3556.048.386.238.969.5 Comparative example 58.4891.885.993.682.990.3Comparative example 65.466.043.666.136.054.5

[0372]

[0373] Referring to Table 2 above, the openness of the double bond is 8.5 Å. 2 In Comparative Examples 1 to 3 using a photosensitive dye exceeding , it was confirmed that the thermal stability was poor and the optical recording characteristics were significantly deteriorated when left at high temperatures. In particular, in Comparative Example 2 using a photosensitive dye with the largest double bond openness, optical recording was impossible after leaving it at 60°C for 30 days. In addition, Comparative Examples 1 to 3 exhibited high △E and low diffraction efficiency.

[0374] Meanwhile, the openness of the double bond is 7 Å 2 In Comparative Examples 4 to 6 using a photosensitive dye of less than 100 nm, contrary to the prediction that the thermal stability would be excellent, the thermal stability was lower than that of Examples 1 and 2, and △E was high and the diffraction efficiency was low.

[0375] Accordingly, it is confirmed that the photopolymer composition according to one embodiment of the invention provides a holographic recording medium having excellent optical recording properties such as diffraction efficiency while securing colorless and transparent optical properties and excellent thermal stability by using a compound having a double bond openness satisfying a specific value as a photosensitive dye.

Claims

1. Comprising a polymer matrix or a precursor thereof; a photoreactive monomer; a photosensitive dye; and a public reagent, The above-mentioned photosensitive dye is a compound including a core represented by the following chemical formula 1, and the openness of the double bond connecting two hetero rings is 7.0 to 8.5 Å. 2 A photopolymer composition comprising a phosphorus compound: [Chemical Formula 1] In the above chemical formula 1, Z is oxygen, sulfur or CR 7 R 8 And, R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

2. A photopolymer composition in claim 1, wherein the polymer matrix is ​​formed by cross-linking a siloxane-based polymer containing a silane functional group and an acrylic polyol.

3. In the first paragraph, the photoreactive monomer is at least one monofunctional monomer selected from the group consisting of benzyl (meth)acrylate, benzyl 2-phenylacrylate, phenoxybenzyl (meth)acrylate, phenol (ethylene oxide) (meth)acrylate, phenol (ethylene oxide) 2 (meth)acrylate, O-phenylphenol (ethylene oxide) (meth)acrylate, phenylthioethyl (meth)acrylate, and biphenylmethyl (meth)acrylate; bisphenol A (ethylene oxide) 2~10 A photopolymer composition comprising at least one polyfunctional monomer selected from the group consisting of di(meth)acrylate, bisphenol A epoxy di(meth)acrylate, bisfluorene di(meth)acrylate, modified bisphenol fluorene di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, phenol novolac epoxy (meth)acrylate, and cresol novolac epoxy (meth)acrylate; or a mixture of two or more thereof.

4. In the first paragraph, the openness of the double bond is a value calculated and added up for each of the two carbon atoms forming the double bond. The openness of the above carbon atom is the area of ​​the open surface area not covered by the substituents relative to the surface area of ​​a sphere with a radius of 1.2 Å from the carbon atom, and is calculated using density functional theory in a quantum chemical calculation program, with B3LYP as the functional and 6-31G as the basis function. * A photopolymer composition, the value of which is calculated using Jmol software.

5. In the first paragraph, the compound including the core represented by the chemical formula 1 has an openness of the double bond connecting two hetero rings of 7.0 to 8.5 Å. 2 The photopolymer composition is a compound represented by the following chemical formula 1-1: [Chemical Formula 1-1] In the above chemical formula 1-1, R 1 is an alkylene group having 1 to 6 carbon atoms, and R 2 is an alkyl group having 1 to 6 carbon atoms, n1 is an integer from 1 to 6, R 3 is an alkyl group having 3 to 12 carbon atoms, R 4 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R 5 and R 6 are each independently a halogen, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, n2 and n3 are each independently integers from 0 to 4, Z is oxygen, sulfur or CR 7 R 8 And, R 7 and R 8 are each independently an alkyl group having 1 to 6 carbon atoms.

6. A photopolymer composition according to claim 1, wherein the photosensitive dye further comprises tetraaryl borate.

7. In the first paragraph, the photopolymer composition comprises a borate anion represented by the following chemical formula 4: [Chemical Formula 4] BX 1 X 2 X 3 X 4 In the above chemical formula 4, X 1 Inland X 4 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an alkylaryl group or an allyl group having 7 to 30 carbon atoms, and X 1 Inland X 4 At least one of them is not an aryl group.

8. In the first paragraph, the photopolymer composition comprises at least one borate anion selected from the group consisting of borate anions represented by the following chemical formulas 4-1 and 4-2: [Chemical Formula 4-1] In the above chemical formula 4-1, R 102 , R 103 and R 104 are each independently hydrogen, methyl, methoxy, halogen, phenyl or vinyl, X 4' is a straight chain alkyl group having 1 to 12 carbon atoms, [Chemical Formula 4-2] In the above chemical formula 4-2, R 106 are each independently hydrogen, methyl, methoxy, halogen or vinyl, X 4" is a straight-chain alkyl group having 1 to 12 carbon atoms.

9. A photopolymer composition according to claim 1, further comprising a photoinitiator, wherein the photoinitiator comprises a phosphine oxide-based compound.

10. A photopolymer composition according to claim 1, further comprising a plasticizer, and including at least one selected from among fluorine compounds represented by the following chemical formulae 5-1 to 5-3 as the plasticizer: [Chemical Formula 5-1] In the above chemical formula 5-1, Z a1 is -O- or -NH-, Z a2 is a single bond, -O- or -NH-, L a1 is a single bond or a 2- to 6-valent organic group in which a hydroxyl group is removed from a polyol having 2 to 6 alcohol groups, na and ma are each independently integers from 1 to 5, and the sum of na and ma is from 2 to 6, R a1 , R a2 and R a3 are each independently a methyl group or an ethyl group, R a4 is a fluorine-containing substituent, an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines. [Chemical Formula 5-2] In the above chemical formula 5-2, Z b1 is -O- or -NH-, Z b2 is a single bond, -O- or -NH-, L b1 is a single bond or a 2- to 6-valent organic group in which a hydroxyl group is removed from a polyol having 2 to 6 alcohol groups, nb and mb are each independently integers from 1 to 5, and the sum of nb and mb is from 2 to 6, R b1 is a methyl group or an ethyl group, R b2 Inland R b4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines, R b2 and R b3 If each of the substituents is not a fluorine-containing substituent, each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-, R b4 If it is not a fluorine-containing substituent, it is an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the above substituent is replaced with -O-, -S-, or -NH-, [Chemical Formula 5-3] In the above chemical formula 5-3, Z c1 and Z c2 are each independently -O-, -S- or -NH-, R c1 Inland R c4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted with two or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with two or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with two or more fluorines, R c1 Inland R c4 When the substituents are not fluorine-containing, each independently represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one -CH2- of the substituents is replaced with -O-, -S-, or -NH-.

11. A holographic recording medium comprising a photopolymer layer formed from the photopolymer composition of claim 1.

12. A hologram recording medium having a diffraction efficiency of 70% or more when recording a notch filter hologram in accordance with claim 11.

13. A hologram recording medium in which, in the 11th paragraph, a notch filter hologram is recorded after being left at a high temperature of 60°C for 30 days before recording, the diffraction efficiency after being left at a high temperature is maintained at 90% or more.

14. In the 11th paragraph, a holographic recording medium in which optical information is not recorded, and in which the △E of the holographic recording medium with respect to white light having the same brightness is 3.0 or less.

15. A method for manufacturing a holographic recording medium, comprising the step of forming a photopolymer layer by applying the photopolymer composition of claim 1.

16. A method for manufacturing a holographic recording medium, comprising the step of irradiating a coherent laser to a predetermined area of ​​the photopolymer layer to selectively polymerize a photoreactive monomer included in the photopolymer layer to record optical information in the 15th paragraph.

17. An optical element comprising a holographic recording medium according to Article 11.

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