JP2013142805A - Rewritable hologram recording material and manufacturing method thereof, and hologram recording and reproduction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rewritable hologram recording material capable of performing rewriting of hologram data by reversibly generating coloring and color fading by light irradiation and stably holding recording data and easy to manufacture, a manufacturing method thereof, and a hologram recording and reproduction system.SOLUTION: A rewritable hologram recording material is provided with a light-sensitive part in which a silver component, a halogen component, and a copper component are contained in a gel whose skeleton component is an organic silane compound. Accordingly, the light-sensitive part has sufficient sensitivity to light with a wavelength of about 405 nm used for hologram recording. Moreover, the absorbance of the light-sensitive part increases in response to light with a specified wavelength (for example, blue light or ultraviolet light), and it can be reduced by irradiating of light with a specified wavelength (visible light). Therefore, a hologram can be written and deleted by light.

Description

  The present invention relates to a rewritable hologram recording material capable of reversibly performing coloring and decoloring by light irradiation, a method for producing the same, and a hologram recording / reproducing system.

  In recent years, with the increase in capacity of information technology, it is necessary to further increase the capacity and density of optical recording media. As a technique capable of realizing a large capacity, a recording technique using a hologram is attracting attention. Hologram records on the photosensitive material a pattern formed by interference fringes generated by the interference between the reference light and the reflected or transmitted light from the direction of the target substance, and the same pattern from the same angle as the reference light. When light of a wavelength is applied, the recorded information emerges due to the light diffraction principle. An optical memory (hologram recording medium) using such a hologram technology is being developed as a next-generation optical memory capable of recording and reproducing large amounts of information on the order of terabits (Tbits) at high speed.

  At present, the mainstream materials for hologram recording media are photopolymer materials and silver salt films that use photopolymerization and diffusion of unreacted monomers as driving forces. A photopolymer material or a silver salt film is a recording medium for writing only, and the recorded information cannot be rewritten. In addition, the photopolymer material has excellent rewriting characteristics due to sufficiently satisfying high-speed recording properties, high reliability of recorded contents, low shrinkage to express it, smoothness with a uniform film thickness, etc. Realization is difficult.

  As rewritable hologram recording media, photorefractive crystals and photochromic materials are considered promising. A photochromic material is a material in which the optical properties (color, fluorescence, etc.) of a substance change reversibly by an external stimulus, and an optical element such as an optical filter, a hologram element, an optical memory, or a light control element Is being developed as a raw material for

  As this photochromic material, a material in which a silver halide photochromic film is formed on a glass substrate is known. For example, Non-Patent Document 1 discloses a photochromic film forming method in which a solution containing an alkoxysilane and a soluble silver salt is applied on a glass substrate and then halogenated in hydrogen chloride gas. In Non-Patent Document 2 and Patent Document 1, a film formed of an alkoxysilane bonded with a hydrocarbon group having a terminal substituted with halogen is heat-treated at a high temperature of, for example, 200 ° C. or more to generate free halogen, A method for forming a photochromic film that produces silver halide is disclosed. In Patent Document 2, a coating solution containing ultrafine particles containing silver, a silicon compound, and a compound that liberates halogen by thermal decomposition is applied onto a glass substrate to form an underlayer film, and further, a silicon compound and copper A method for producing photochromic glass is disclosed in which an upper layer film is formed by applying and heating a coating solution containing a compound.

  Further, Patent Document 3 discloses a method for producing an inorganic-organic hybrid film using organoalkoxysilane, alkoxytitanium, silver, and halogen.

JP 2000-109344 A JP 2001-39739 A JP 2011-1112917 A

SPIEProc., 1590, 152-159 (1991) J. et al. Sol-GelSci. Tech., 1,217-231 (1994)

  However, the photorefractive crystal has problems such as low sensitivity to light and application of a high electric field at the time of recording, and loss of data naturally after long-term storage. In addition, in the technique described in Non-Patent Document 1, hydrogen chloride gas is allowed to act on the raw material composition to produce silver chloride. Therefore, the gas is highly corrosive, inconvenient to handle, and poor in productivity. There was a problem.

  Furthermore, in the techniques described in Non-Patent Document 1 and Patent Document 1, it is difficult to apply to a substrate such as a resin having low heat resistance, and a silver halide crystal grows and becomes coarse by heat treatment, resulting in a photochromic property. There was a problem of being damaged. In addition, when silver halide is produced by such high-temperature heat treatment, the resulting photochromic material can be colored (recording information) by irradiating it with ultraviolet rays, but in order to cause fading (erasing recorded information). Has a problem that it requires heat treatment.

  In the technique described in Patent Document 2, after the obtained photochromic material is colored by irradiating with ultraviolet rays, it can be faded if left in a dark place at room temperature. However, since it is necessary to form the photochromic material in two layers, there is a problem that the process becomes complicated and the manufacturing cost may increase. Furthermore, since the resulting photochromic material is naturally discolored when left in the dark due to the color produced by ultraviolet irradiation, when such a photochromic material is applied as a recording medium, it is difficult to maintain recorded information for a long period of time. As a result, there arises a problem that it is difficult to ensure the reliability of the information and to rewrite the information at any timing of the user.

  In addition, these photochromic material technologies can induce changes in optical properties by reduction with ultraviolet light, but it is difficult to provide sufficient sensitivity to light near 405 nm required for hologram recording media. Met.

  Against this backdrop, the applicants of the present invention have invented an inorganic-organic hybrid film using organoalkoxysilane, alkoxytitanium, silver, and halogen as shown in Patent Document 3 as a result of intensive studies. In this case, the hybrid film has sufficient sensitivity to light near 405 nm, can perform holographic recording well, does not require chlorine gas, and does not require high-temperature heat treatment. Based on the sol-gel process, it can be easily produced as a single-layer coating film.

  However, the hybrid film also has a problem that the color generated at 405 nm cannot be erased unless it is subjected to heat treatment. When heat treatment is performed when rewriting the information recorded on the hologram recording medium, a heat source must be provided, and the rewritable hologram recording apparatus becomes large.

  The present invention has been made to solve the above-described problems, and can rewrite hologram data by reversibly causing coloring and fading by light irradiation, and can stably hold recorded data. Another object of the present invention is to provide a rewritable hologram recording material that is easy to manufacture, a method for manufacturing the same, and a hologram recording / reproducing system.

  In order to achieve this object, the rewritable hologram recording material according to claim 1 is based on the fact that the silver component reversibly changes from a silver ion or silver halide state to a metallic silver state by an oxidation-reduction reaction. A hologram is recorded so as to be rewritable, and includes a photosensitive portion containing a silver component, a halogen component, and a copper component in a gel having an organosilane compound as a skeleton component, and the photosensitive portion is In response to light of a specific wavelength, the silver component contained in the gel is reversibly converted from silver ion or silver halide to metallic silver, whereby the absorbance changes.

  Note that “reversibly change” means that silver ions or silver halide changes to metal silver upon reduction, and metal silver changes to silver ion or silver halide upon oxidation.

  The rewritable hologram recording material according to claim 2 is the rewritable hologram recording material according to claim 1, wherein the photosensitive part is formed by mixing a silver component, a copper component, and a halogen component with a precursor of an organosilane compound. It is formed by gelling a sol obtained by hydrolysis in a state.

  The rewritable hologram recording material according to claim 3 is the rewritable hologram recording material according to claim 1 or 2, wherein the photosensitive part is formed in a film-like body.

  The rewritable hologram recording material according to claim 4 is the rewritable hologram recording material according to any one of claims 1 to 3, wherein the halogen component is one or more selected from chlorine, fluorine, bromine, and iodine. It is an ingredient.

  The rewritable hologram recording material according to claim 5 is the rewritable hologram recording material according to any one of claims 1 to 4, wherein the precursor of the organosilane compound is a 3-glycidoxypropyl group, a vinyl group, or a phenyl group. One or a plurality of alkoxides selected from trimethoxysilane or triethoxysilane having any of a group, an ethyl group, and a methyl group are included.

  The rewritable hologram recording material according to claim 6 is the rewritable hologram recording material according to any one of claims 1 to 5, wherein the silver component and the copper component are present in an equivalent amount in the gel of the photosensitive portion. The rewritable hologram recording material according to claim 1, wherein at least a part of each of the silver component and the copper component is dispersed in the gel as nanoparticles of a halide.

  The method for producing a rewritable hologram recording material according to claim 7 is capable of rewriting a hologram based on a reversible change of a silver component from a silver ion or silver halide state to a metallic silver state by an oxidation-reduction reaction. A method for producing a rewritable hologram recording material to be recorded, wherein a sol is produced by hydrolysis in a state where a silver component, a copper component and a halogen component are mixed with a precursor of an organosilane compound, Using the sol obtained in the sol preparation step, a gel forming step for forming a gel in which the silver component, the halogen component and the copper component are retained, and drying the gel formed in the gel forming step at a temperature of 60 ° C. or less And a drying step, and the gel obtained through the drying step forms a photosensitive portion in which the absorbance changes in response to irradiation light of a specific wavelength.

  Note that “reversibly change” means that silver ions or silver halide changes to metal silver upon reduction, and metal silver changes to silver ion or silver halide upon oxidation.

  The method for producing a rewritable hologram recording material according to claim 8 is the method for producing a rewritable hologram recording material according to claim 7, wherein the sol produced in the sol production step has a silver component and a copper component, etc. Amount included.

  A hologram recording / reproducing system according to claim 9 is a rewrite produced by the rewritable hologram recording material according to any one of claims 1 to 6 or the method for producing the rewritable hologram recording material according to claim 7 or 8. Hologram recording material, laser irradiating means for irradiating the rewritable hologram recording material with a two-beam blue laser beam of signal light and reference light, and the rewriting in which the hologram is recorded by interference exposure by the laser irradiating means The hologram sensitive recording material is irradiated with reference light from the laser irradiating means to reproduce the hologram, and the visible light having a wavelength longer than the blue laser light of the laser irradiating means is irradiated. A hologram recorded on the photosensitive part of the rewritable hologram recording material by light irradiation by the visible light irradiation means. It is to be erased.

  According to the rewritable hologram recording material according to claim 1, since the gel having an organic silane compound as a skeleton component includes a photosensitive portion containing a silver component, a halogen component, and a copper component, There is an effect that the photosensitive part can have sufficient sensitivity to light near 405 nm used for hologram recording. Therefore, a material suitable for hologram recording can be obtained. Here, the light sensitive part of this material is sensitive to light of a specific wavelength (for example, blue light or ultraviolet light), and the silver halide or silver ion contained in the gel changes to metallic silver. Absorbance increases (colors). On the other hand, this material is capable of reducing (discoloring) absorbance by converting metal silver in the gel into silver halide or silver ion when irradiated with light of a specific wavelength (for example, visible light). . That is, since the absorbance can be changed by light irradiation, the hologram can be written and erased by light.

  This eliminates the need for heat treatment on the recording material in order to rewrite the hologram. Therefore, heating means such as a heat source can be eliminated, and the apparatus for rewriting the hologram can be reduced in size.

  In addition, since this material does not require a complicated wet development process when recording a hologram, recording can be performed easily and a redox reaction can be induced reversibly. There is an effect that it can be repeated.

  In addition, the rewritable hologram recording material does not cause significant coloring or fading even when exposed to a daily environment indoors, and the colored state is maintained even when the colored material is stored in the dark. . Therefore, unlike a photochromic glass in which a film containing silver halide and copper is formed, discoloration does not occur due to standing in a dark place at room temperature after coloring by light irradiation. In other words, it is possible to provide a highly reliable recording material that can avoid a situation in which data recorded due to natural fading is inadvertently lost, and that can stably hold the recording data.

  According to the rewritable hologram recording material according to claim 2, in addition to the effect exerted by the rewritable hologram recording material according to claim 1, the photosensitive part is composed of an organic silane compound containing a silver component, a copper component, and a halogen component. Since it is formed into a gel using a sol obtained by hydrolysis in a mixed state with a precursor, there is an effect that it can be easily manufactured based on a general-purpose sol-gel process. Further, it is possible to eliminate the use of a halogen gas when introducing the halogen component, and it is possible to simplify the process management during production. In addition, since it is manufactured without a baking process like conventional photochromic glass, a photosensitive part can be formed on a substrate such as a resin having low heat resistance. There is an effect that loss of photochromic characteristics (sensitivity to light) due to crystal growth and coarsening can be avoided.

  According to the rewritable hologram recording material according to claim 3, in addition to the effect exhibited by the rewritable hologram recording material according to claim 1 or 2, the photosensitive part is formed in a film-like body. Can be handled in the same way as existing recording media such as compact discs (CD), digital versatile discs (DVD), and Blu-ray discs, and is easy to use and has a common device for playback and rewriting. There is an effect of obtaining. In addition, for example, if a method of directly applying or coating a sol on a desired base material is used, there is an effect that the photosensitive part can be easily formed.

  According to the rewritable hologram recording material according to claim 4, in addition to the effect exerted by the rewritable hologram recording material according to any one of claims 1 to 3, the halogen component includes chlorine, fluorine, bromine and iodine. Therefore, there is an effect that a halogen component can be introduced into the gel using a commercially available product (halide) that is easily available as a raw material.

  According to the rewritable hologram recording material according to claim 5, in addition to the effect exhibited by the rewritable hologram recording material according to any of claims 1 to 4, the precursor of the organosilane compound is 3-glycidoxy Since it contains one or a plurality of alkoxides selected from trimethoxysilane or triethoxysilane having any of propyl group, vinyl group, phenyl group, ethyl group, and methyl group, There is an effect that the formed photosensitive portion can have good photosensitivity.

  According to the rewritable hologram recording material according to claim 6, in addition to the effect exhibited by the rewritable hologram recording material according to claims 1 to 5, the silver component and the copper component are present in an equivalent amount in the gel, Each of the component and the copper component is at least partially dispersed in the gel as halide nanoparticles. Here, the larger the size of the silver particles, the lower the photochromic properties. However, since the silver halide particles are composed of nanoparticles in the present recording material, there is an effect that good photochromic properties can be expressed. . Furthermore, since the copper component is present in an equal amount relative to the silver component, the effect of the copper component can be sufficiently exerted on the silver component, and the photochromic characteristics can be further improved.

  According to the method for producing a rewritable hologram recording material according to claim 7, it is obtained by performing hydrolysis in a state where a silver component, a copper component, and a halogen component are mixed with a precursor of an organosilane compound by a sol preparation step. Using the obtained sol, a gel in which the silver component, the halogen component, and the copper component are retained is formed in the gel formation step. And the gel is dried at the temperature of 60 degrees C or less by a drying process. As a result, the photosensitive part is formed with a gel that maintains moisture retention, and since it is dried at a relatively low temperature below 60 ° C., growth and coarsening of silver halide crystals are suppressed. it can. As a result, it is possible to provide a rewritable hologram recording material that can induce a redox reaction of silver satisfactorily by light irradiation, and can record and erase information (hologram) reversibly by light irradiation. There is an effect.

  Further, since the present manufacturing method is based on a sol-gel process, a rewritable hologram recording material can be manufactured simply and easily using an existing production system. In addition, since the firing step provided when manufacturing photochromic glass from a normal sol-gel process can be made unnecessary, there is an effect that energy costs for manufacturing can be suppressed. Furthermore, since the light sensitive part can be formed on a base material such as a resin having low heat resistance, it can be easily manufactured in a form corresponding to various uses required by the user. When the material is used for the base material, there is an effect that the manufacturing cost can be further suppressed as compared with the case where the inorganic material is used for the base material.

  According to the method for producing a rewritable hologram recording material according to claim 8, in addition to the effect exhibited by the method for producing a rewritable hologram recording material according to claim 7, the sol produced in the sol production step is a silver component. Since the copper component and the copper component are contained in equal amounts, the effect of the copper component can be sufficiently exerted on the silver component, and the photochromic characteristics of the resulting rewritable hologram recording material can be further improved.

  According to the hologram recording / reproducing system of claim 9, the hologram recording / reproducing system according to claim 1 is manufactured by the method of manufacturing the rewritable hologram recording material according to any one of claims 1 to 6 or the rewritable hologram recording material according to claim 7 or 8. Using the rewritable hologram recording material, hologram recording can be performed by irradiation with two-beam blue laser light of signal light and reference light. Moreover, the recorded hologram can be reproduced by irradiating the reference light by the hologram reproducing means, and erasing the recorded hologram by irradiating visible light having a wavelength longer than the blue laser light by the visible light irradiating means. There is an effect that can be. That is, recording and erasing of the hologram can be performed using light, and the apparatus can be downsized as compared with the case of erasing the recorded hologram with heat.

1 is a schematic diagram of a hologram reproduction system that is an embodiment of the present invention. It is the graph which showed the ultraviolet-visible absorption spectrum at the time of performing blue laser irradiation and visible light irradiation (490-550 nm). 3 is a graph showing the absorbance characteristics when the test piece prepared in Example 1 is repeatedly irradiated with light. It is the graph which showed the time change of the diffraction efficiency during blue laser interference exposure.

  Hereinafter, the present invention will be described in detail. The rewritable hologram recording material of the present invention is a photochromic material and is configured such that the absorbance changes in response to light. The light sensitive part that is sensitive to light is formed of a gel, and the gel contains a silver component, a copper component, and a halogen component.

In the present invention, the photochromic phenomenon is mainly caused by the silver component in the gel. Here, the silver component is present in the gel in any state of silver halide (compound), silver ion (Ag ⁺ ion), silver (metal silver, free silver), and silver halide and free silver Is contained in the gel in the form of nanoparticles. The silver halide used in the present invention is AgF, AgCl, AgBr, AgI and a mixture thereof or a solid solution thereof, preferably AgCl, AgBr, and particularly preferably AgCl. Note that free silver, that is, metallic silver, is a metal embodiment, and changes to silver ions or silver halide by an oxidation reaction. It will change. For this reason, metallic silver is not limited to a simple substance (pure silver) as long as the absorbance is changed by causing such an oxidation-reduction reaction, and is a concept including a silver alloy having the same action.

  The silver halide contained in the gel film is a nanoparticle having a particle size of 20 nm or less, preferably 2 nm to 10 nm, which can exhibit good photochromic characteristics, and realizes good resolution when used as a rewritable hologram recording material. it can. Also, in order to ensure a dynamic range and spatial resolution that can sufficiently detect changes in absorbance, it is necessary that the silver component be present uniformly in the gel film at a sufficient concentration. However, this material is designed so that it may become 1-30 mol% with respect to the gel film of a matrix.

  The copper component is known as an additive (sensitizer) that improves the photochromic properties of silver halide. In the present invention, the presence state of copper is not particularly limited. For example, copper may be simple substance, or may be present in the form of an alloy, a compound, or an ion. The gel is preferably contained in the form of copper halide. Examples of the copper halide include CuF, CuCl, CuBr, CuI, and a mixture thereof or a solid solution thereof, and CuCl is preferably used.

  Further, the copper component may form an alloy with silver, may exist in a form covering so-called silver fine particles (so-called core-shell structure), and further, as a copper nanoparticle separately from silver May be present. Preferably, the copper component is preferably present separately from the silver component as nanoparticles.

  The blending amount of the copper component is appropriately selected according to the blending amount of the silver component, and is adjusted within a range in which the photochromic characteristics of the silver component can be improved. Preferably, the copper content and the silver content are blended in the gel film in equivalent amounts.

  The silver halide and copper halide retained in the gel may be introduced into the gel as silver halide or copper halide itself, and are derived from other compounds in the sol or gel by reaction. May be. Preferably, the silver halide and the copper halide are prepared by allowing a silver compound other than a halide and other copper compound and a halogen component to coexist in a sol or gel, thereby allowing the silver compound, the copper compound and the halogen component to coexist. It is introduce | transduced into a gel by making and react.

  In the rewritable hologram recording material of the present invention, the photosensitive part is formed of gel as described above. Here, the gel has a support structure over the entire system and includes liquid components or voids. In other words, it is a solid material in which a liquid component is held between solid-phase frameworks (skeleton components).

  The gel forming the photosensitive part of the rewritable hologram recording material of the present invention has a supporting structure (skeleton component) made of an organosilane compound. This gel is formed by further promoting the reaction and solidifying it from a sol that can be obtained through hydrolysis and polycondensation of the precursor alkoxysilane (organosiloxane). The organosilane compound having a supporting structure is polymerized to form a siloxane polymer. A liquid (water) is contained in the gel, but the rewritable hologram recording material of the present invention is in a mode close to a dry gel having a low liquid content compared to a so-called jelly-like material.

  In the present invention, various organosiloxanes can be used as appropriate as the precursor organosiloxane for forming the siloxane polymer. For example, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra n-propoxysilane, Tetra n-butoxy silane, tetra sec-butoxy silane, tetraisobutoxy silane. Methyltrimethoxysilane, methyltriethoxysilane, methyltriisoropoxysilane, methyltrin-propoxysilane, methyltrin-butoxysilane, methyltrisec-butoxysilane, methyltriisobutoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, Examples include ethyl triisopropoxy silane, ethyl tri n-propoxy silane, ethyl tri n-butoxy silane, ethyl tri sec-butoxy silane, ethyl triisobutoxy silane and the like.

  Alternatively, an organosiloxane having a vinyl group may be used. Examples of the organosiloxane include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrin-propoxysilane, vinyltrin-butoxysilane, and vinyltrimethoxysilane. Examples thereof include sec-butoxysilane and vinyl triisobutoxysilane.

  In addition, an organosiloxane having an aromatic ring may be used as the organosiloxane, for example, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltrin-propoxysilane, phenyltrin-butoxy. Examples include silane, phenyltrisec-butoxysilane, phenyltriisobutoxysilane, and the like.

  Furthermore, an organosiloxane having an epoxy group or a glycidoxy group may be used, for example, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane. 2- (3,4-epoxycyclohexyl) ethyltriisopropoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri-n-propoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri-n-butoxysilane, 2 -(3,4-epoxycyclohexyl) ethyltrisec-butoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriisobutoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane 3-glycidoxypro Lutriisopropoxysilane, 3-glycidoxypropyltri-n-propoxysilane, 3-glycidoxypropyltri-n-butoxysilane, 3-glycidoxypropyltrisec-butoxysilane, 3-glycidoxypropyltriisobutoxy Orchid, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldiisopropoxysilane, 3-glycidoxypropylmethyldi-n-propoxysilane, 3- Examples include glycidoxypropylmethyldi n-butoxysilane, 3-glycidoxypropylmethyldisec-butoxysilane, 3-glycidoxypropylmethylditriisobutoxysilane, and the like.

  These organosiloxanes may be used alone or in combination. Among these, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltri Ethoxysilane is preferably used. In particular, those having an organic functional group such as an unsaturated group such as vinyl or an epoxy-containing group such as glycidyl or epoxy are preferably used. Vinyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane are used. When vinyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane are used, an increase in the photosensitivity of the gel film is observed.

  The gel has a thickness of 50 nm to 50 μm, and preferably 1 μm to several μm. In general, it is known that the diffraction efficiency by a hologram is improved by increasing the thickness of the photosensitive layer. However, it is difficult to increase the thickness of a photorefractive crystal or photochromic glass due to a problem of cracking. However, since the photosensitive part of this material is formed of gel, cracks are hardly generated even when the film is thickened, and a photosensitive part having a thickness of several μm can be easily formed. Therefore, the recording characteristics can be greatly improved by increasing the film thickness.

In the rewritable hologram recording material of the present invention configured as described above, it is presumed that photochromism is expressed by an oxidation-reduction reaction mechanism represented by the following reaction formula (1). That is, when a gel containing silver halide (monovalent) and copper halide (monovalent) is irradiated with light hv ₁ (blue light to ultraviolet light), free silver is generated from silver halide (or silver ions). , The corresponding halogen reacts with copper halide (monovalent) to produce copper halide (divalent). The resulting free silver nanoparticles increase the absorbance and cause coloration. The wavelength range of hv ₁ is 280 nm to 410 nm (from ultraviolet light to blue light), and silver halide can be changed to free silver in response to light having such a wavelength. Here, it is preferable to change from silver halide to free silver using a wavelength of 375 nm to 410 nm, considering that the coherence decreases as the wavelength becomes shorter in ultraviolet light and the wavelength of an easily available laser. Furthermore, since a commercially available blue laser can be used, it is even more preferable that a wavelength of 400 nm to 410 nm is used.

尚、反応式（１）において、Ｘはハロゲンである。

In the reaction formula (1), X is halogen.

Further, when light hv ₂ (visible light having a longer wavelength than blue light) is irradiated on a gel in which free silver and copper halide (divalent) coexist, free silver is more halogen atom than copper halide (divalent). Is converted into silver halide (monovalent). Here, it is included that the silver halide is a halogen ion and a silver ion, that is, the concept that free silver is changed to a silver ion is also included. This reaction reduces the absorbance and causes discoloration. This oxidation-reduction reaction by light irradiation, that is, precipitation of free silver and halogenation can be realized repeatedly. Here, precipitation of free silver means that silver halide or silver ions change to silver in a metallic form, not only from precipitation as nanoparticles but also as nanoparticles. It also includes the change of silver halide nanoparticles to silver nanoparticles.

Further, the wavelength range of hv ₂ is 450 nm to 1000 nm (from the longer wavelength side to the entire visible light side than blue light), and free silver can be changed to silver halide in response to light of such wavelength. Here, the shorter the wavelength, the faster the free silver can be changed to silver halide. On the other hand, since a commercially available red laser can be applied, light of 490 nm to 800 nm is preferably used, and 490 nm to 650 nm. The light of 490 nm to 550 nm is particularly preferably used.

  By providing the rewritable hologram recording material of the present invention with the above-described configuration, it can be sufficiently sensitive to blue light suitable for hologram recording and practically important, particularly a wavelength around 405 nm. For this reason, by irradiating this material with blue light, the silver halide in the gel can be changed to silver and colored. Therefore, if the photosensitive portion is formed in a film shape to form a disk shape, a large amount of data on the order of terabits per disk can be recorded. In addition, a large amount of data can be recorded and reproduced at high speed with blue light.

  Furthermore, the silver in the gel can be changed to silver halide and faded by irradiation with visible light having a wavelength longer than that of blue light. For this reason, the hologram can be recorded so as to be rewritable.

  Conventionally, for example, photochromic glass using a film containing silver halide has been proposed. This photochromic glass film containing silver halide and copper is designed to cause fading when left in a dark place at room temperature after being colored with ultraviolet light. However, when such a photochromic glass technique is applied to a hologram recording material, data recorded by natural fading will be lost carelessly, resulting in poor reliability as a recording material.

  However, even if the rewritable hologram recording material is exposed to a daily environment indoors, no significant coloring occurs and no fading occurs. Furthermore, even if the colored material is stored in a dark place, no fading occurs. Note that the indoor environment is a state in which direct sunlight is not irradiated. On the other hand, it can be faded by irradiating light of a predetermined wavelength. That is, the fading reaction can be remarkably induced by increasing the intensity of the irradiated light as compared with the exposure in an indoor environment. Therefore, recording and erasing can be repeatedly performed at any timing of the user, and a high-quality and highly reliable rewritable hologram recording material can be obtained.

  Furthermore, since the rewritable hologram recording material is formed by using a three-dimensional network structure siloxane polymer dry gel having a low liquid content, the rewritable hologram recording material itself has low shrinkage, and has mechanical strength and durability. It can be made excellent.

  In addition, the rewritable hologram recording material of the present invention may be composed of only a gel, or a gel laminated on a base material. Further, the substrate is not necessarily flat. Preferably, the rewritable hologram recording material of the present invention comprises a gel formed as a film on a substrate. Various inorganic materials can be applied to the support, such as inorganic glass such as soda lime glass, alkali-free glass, quartz glass, aluminoborosilicate glass, phosphate glass, alumina, zirconia, titania, etc. Examples include ceramics, and metals and alloys such as aluminum, titanium, copper, and stainless steel.

  In addition, since a firing step is not necessary in the manufacturing process of the recording material, a material having low heat resistance can be used as a base material, and an organic material may be used instead of the inorganic material. Such an organic material is not particularly limited as long as it has heat resistance and water resistance at 60 ° C., and examples thereof include polystyrene, polyamide, polyimide, polycarbonate, acrylic resin, epoxy resin, and polyester resin. Is appropriately selected.

  In the present invention, the gel is not necessarily formed into a film-like body. For example, fine particles obtained by solid-liquid separation of the prepared sol may be dried to form a particulate gel, or the gel obtained from the film-like body may be pulverized and subdivided to form a particulate gel. The particulate gel thus obtained may be used as the rewritable hologram recording material of the present invention, for example, by dispersing it in a polymer as a binder and then forming a coating film.

  Further, in the present recording material, the absorbance increases when the silver component changes from ion or halide to metal (precipitation), and the absorbance decreases when the silver component changes from metal to ion or silver halide. “Recording a hologram in a rewritable manner based on reversible change” described in the claims means that the hologram is recorded by setting the state of high absorbance as the initial state and decreasing the absorbance. Alternatively, the hologram may be recorded by increasing the absorbance by setting the low absorbance state as the initial state. Preferably, since hologram writing is performed with blue light, the material is used as a hologram recording by setting the state sensitive to blue light as an initial state and increasing the absorbance by irradiation with blue light. The

  Next, a preferred embodiment of a manufacturing method for manufacturing the rewritable hologram recording medium of the present invention will be described. In addition, although this embodiment demonstrates the method of forming the gel which is a photosensitive part in a film-like body, the scope of the present invention is not limited to these forms.

  In this manufacturing method, a gel is formed based on a sol-gel method. Further, the gel to be formed contains a silver component, a copper component, and a halogen component, and a gel film is formed so that silver halide and copper halide are held in the gel as specific substances. .

  The silver component retained in the gel is preferably introduced into the gel using another silver salt (silver compound) instead of the silver halide itself. Specific examples of such silver compounds include silver acetate, silver benzoate, silver carbonate, silver chromate, silver cyanate, silver cyclohexanebutyrate, silver dichromate, silver diethyldithiocarbamate, silver fluoride, silver lactate, silver mesila. -Silver methanesulfonate, silver nitrate, silver nitrite, silver perchlorate, silver phosphate, silver sulfate, silver tetrafluoroborate, silver p-toluenesulfonate, silver trifluoroacetate, silver vanadate, and the like A mixture can be mentioned, Among these, 1 type or multiple types are selected suitably. Preferably, those having good solubility in water are used, and silver nitrate, silver sulfate and the like are preferable, and silver nitrate is particularly preferable.

  Further, as for the copper component retained in the gel, like the silver component, copper halide may be directly introduced into the gel, but it is desirable to introduce it into the sol or gel using another copper compound. As a copper compound to be used, for example, an inorganic salt such as copper nitrate, copper chloride, copper bromide or copper sulfate, or an organic salt such as copper acetate can be selected. From the viewpoint of solubility in water, one or more copper compounds selected from copper nitrate, copper chloride, copper sulfate, and copper acetate are preferably used, and copper sulfate is particularly preferably used.

  By making a halogen component coexist in these silver compound and copper compound, silver halide and copper halide are generated and held in the gel.

  The halogen component is introduced into the gel by using halogeno fatty acids. Examples of such halogeno fatty acids include, but are not limited to, tribromoacetic acid, trichloroacetic acid, triiodoacetic acid, and the like. Such halogeno fatty acids are used as raw materials together with the above-described silver compound and copper compound, and when these react, at least part of the silver component, copper component, and halogen component becomes silver halide and copper halide. Retained in the gel.

  In addition to the above silver compound, copper compound, halogeno fatty acid, and further using organosiloxane as a raw material, a sol-shaped hologram composition containing a condensation polymer obtained by first mixing under acidic conditions and performing hydrolysis Prepare. This process corresponds to the sol preparation process described in the claims. Although the sol-gel reaction can be performed under basic conditions, in this embodiment, the reaction is preferably performed under acidic conditions, and in particular, the sol is prepared in the presence of an acid such as nitric acid. It is preferable. As a result, the gel formed from such a sol contains a large amount of moisture and alcohol as a by-product.

  Moreover, since the spatial resolution and the dynamic range of the absorbance of the gel to be formed depend on the compounding amount and particle size of the silver compound, the silver content is preferably 1 to 30 mol% with respect to the gel film. The silver compound is blended so as to be in the range.

  Furthermore, in order to improve the wettability of the coating film surface and improve the dispersibility of the colloid, the sol-shaped hologram composition may include a silicon-based surfactant, a fluorine-based surfactant, a non-ionic surfactant. A dispersant such as a surfactant may be added. In addition, various antioxidants may be added to improve durability and weather resistance, and a pH adjusting agent may be added to stabilize the colloid.

  Next, the prepared sol is coated on a substrate and gelled by drying or the like to form an organosilsesquioxane gel film (photosensitive portion). The method of coating the sol on the substrate is not particularly limited. For example, the transparent substrate may be coated as a gel film by a dip coating method, and may have a desired shape according to the application in mass production industrially. In order to produce a thing, you may coat by a spin coat or a doctor blade method. In addition, the process of performing this coating corresponds to the gel formation process of a claim.

  Moreover, it is preferable that it is 60 degrees C or less as drying conditions, and it is still more preferable that it is 30 degrees C or less. The step of drying the gel under such conditions corresponds to the drying step described in the claims. Thereby, a rewritable hologram recording medium in which silver halide and copper halide nanoparticles having a particle diameter of 20 nm or less, preferably 10 nm or less, are uniformly dispersed in the gel film is obtained.

  As described above, the method for producing a rewritable hologram recording material of the present invention can produce the rewritable hologram recording material simply and easily by the sol-gel method with high production efficiency. Moreover, a silver component, a copper component, and a halogen component are introduced into a gel by mixing a silver compound, a copper compound, and a halogeno fatty acid with an organosiloxane to prepare a sol, and forming a gel from the sol. As a result, even when the film is thickened, the composition (distribution state of silver halide and copper halide) can be made uniform throughout the film, and the silver halide and halide that can be retained throughout the gel. The amount of copper can be increased. Accordingly, the recording characteristics can be improved.

  Furthermore, in this production method, halogen is introduced into the gel film without using halogen gas, so that no corrosive gas is generated during production, and productivity can be improved. Furthermore, a large apparatus such as a firing furnace required for manufacturing photochromic glass is not required, and the entire manufacturing system can be downsized.

  The above manufacturing method forms a film-like gel. Instead of this, for example, fine particles obtained by solid-liquid separation of the prepared sol are dried to produce a particulate gel. The rewritable hologram recording material may be manufactured by forming a film by dispersing the particulate gel in, for example, a polymer. Further, a rewritable hologram recording material having an arbitrary gel film thickness may be produced by uniformly dispersing the sol-shaped hologram composition obtained by the above production method in a resin as it is. In such a case, it is preferable to separate and remove silver halide grains and copper halide grains exceeding 100 nm which have been aggregated and enlarged using centrifugation, natural sedimentation, or the like.

  Furthermore, when it is not necessary to consider the concentration gradient of the composition in the film thickness direction (for example, when the photosensitive part is formed as a thin film), a silver compound, a copper compound, and a halogeno fatty acid are added to the preformed gel. Each component or a mixed solution of such substances may be applied, sprayed, dipped, etc., and each component may be held in the gel.

  Next, a hologram recording / reproducing apparatus 1 according to an embodiment of the present invention will be described with reference to FIG. 1, but the scope of the present invention is not limited to these embodiments.

  FIG. 1 is a schematic configuration diagram of a hologram recording / reproducing apparatus 1. The hologram recording / reproducing apparatus 1 is configured to be able to record, reproduce, and erase holograms using the above-described rewritable hologram recording material of the present invention as a medium.

  Specifically, the hologram recording / reproducing apparatus 1 can write, read, and erase holograms by light irradiation, and includes a laser light source 10 for that purpose. The laser light source 10 includes a blue laser 11 and a red laser 12. The blue laser 11 is a light source for recording and reproducing holograms on the hologram recording material, and outputs 405 nm laser light. This wavelength of 405 nm is a wavelength suitable for hologram recording and is a wavelength of a light source used in a Blu-ray disc drive. Therefore, the hologram recording / reproducing apparatus 1 can be a drive compatible with a Blu-ray disc.

  The red laser 12 outputs irradiation light for erasing the hologram recorded on the rewritable hologram recording material of the present invention, and outputs visible light having a wavelength longer than that of blue light. In this embodiment, the laser beam is designed to output 780 nm or 650 nm laser light. 780 nm is a wavelength of a light source used in a drive of a compact disc (hereinafter simply referred to as “CD”). Further, 650 nm is a wavelength of a light source used in a drive for a digital versatile disk (hereinafter simply referred to as “DVD”). Therefore, the hologram recording / reproducing apparatus 1 can be a drive compatible with CD or DVD. Thus, the hologram recording / reproducing apparatus 1 can be formed without providing a new light source for the existing Blu-ray disc and DVD reproducing system.

  In the hologram recording / reproducing apparatus 1, when recording and reproducing a hologram, the blue laser 11 is turned on while the red laser 12 is turned off.

  The laser light output from the blue laser 11 enters the beam splitter 13. The beam splitter 13 separates the laser beam that has entered into signal light (signal beam) and reference light (reference beam). As a result, the light beam entering the beam splitter 13 becomes two light beams, which are output as signal light and reference light from different directions. In FIG. 1, the waveguide of the laser light output from the blue laser 11 is indicated by a solid line L1, the waveguide of the signal light is indicated by a solid line L1a, and the waveguide of the reference light is indicated by a solid line L1b.

  The signal light then enters the spatial light modulator 14. The spatial light modulator 14 modulates light with a pixel pattern corresponding to recording information. Thereby, the modulated signal light is irradiated to the medium S set at a predetermined position via the mirrors 15 and 16. This medium S is the rewritable hologram recording material of the present invention. The mirror 16 is formed of a movable mirror so that the irradiation position can be moved.

  In addition, the reference light output from the beam splitter 13 is irradiated through the mirror 17 so as to overlap the signal light on the medium S, and as a result, interference fringes (page pattern) between the signal light and the reference light. A hologram is recorded. The mirror 17 is composed of a movable mirror so that the irradiation position can be moved.

  At this time, if the modulation pattern (pixel pattern or phase pattern) of the signal light and the reference light is changed without displacing the irradiation part of the hologram recording medium, various page patterns corresponding to the modulation pattern are displayed on the irradiation part. Are recorded in a multiplex manner. Thereby, a phase code multiplexing system is realized.

  When reproducing the recorded hologram, the output intensity of the blue laser 11 is weakened, and the light is cut by the spatial light modulator 14 so that only the reference light is irradiated onto the medium S. Thereby, the information recorded on the medium S is reproduced. Such a configuration in which only the reference light is irradiated onto the medium S corresponds to the hologram reproducing means described in the claims.

  When erasing the recorded hologram, control is performed so that the red laser 12 is turned on and the blue laser 11 is turned off. Mirrors 18 and 19 are provided on the optical path of the red laser light. Then, the output light from the red laser 12 enters the beam splitter 13 through the mirrors 18 and 19. Then, it is separated into two light beams by the beam splitter 13 and outputted as signal light and reference light from different directions. In FIG. 1, the waveguide of the laser light output from the red laser 12 is indicated by a broken line L2, the waveguide of the signal light is indicated by a broken line L2a, and the waveguide of the reference light is indicated by a broken line L2b.

  The red laser light output from the beam splitter 13 irradiates the medium S with the signal light via the spatial light modulator 14 and the mirrors 15 and 16 in the same manner as the blue laser light. Further, the reference light is irradiated on the medium S so as to overlap with the signal light via the mirror 17. As a result, the hologram recorded at the position written by the blue laser beam is erased.

  The present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention. Can be easily guessed. For example, the hologram recording / reproducing apparatus 1 includes the blue laser 11 for writing the hologram, but an ultraviolet laser may be provided instead. The red laser 12 is provided as a laser for erasing the hologram. However, the laser is not limited to the red laser beam as long as the recorded hologram can be erased. For example, a green laser is provided instead of the red laser 12. Also good.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
Organosiloxane 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) (hereinafter simply referred to as “GP-TMS”), silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and copper sulfate (Wako Pure Chemical Industries, Ltd.), trichloroacetic acid (Wako Pure Chemical Industries, Ltd.) dissolved in a molar ratio of 1: 1: 2, an acidic nitric acid aqueous solution (nitric acid concentration 1.2 mM) was added, and Si was added. : Ag molar ratio was adjusted to 10: 1, and organosiloxane was hydrolyzed at room temperature and normal pressure for 1 hour to obtain a sol.

  The obtained sol was dip-coated on a commercially available slide glass (manufactured by ASONE Co., Ltd.) and dried overnight at room temperature to obtain a test piece on which a gel film having a thickness of about 2 μm serving as a rewritable hologram recording material was formed. . The obtained film was subjected to X-ray diffraction by an X-ray diffractometer (RINT-2000, CuKa manufactured by Rigaku Corporation). Moreover, when observation was performed using a transmission electron microscope (JEM-2100F manufactured by JEOL Ltd.), formation of silver chloride (monovalent) and copper chloride (monovalent) nanoparticles was confirmed in the film. It was. The particle size of the nanoparticles was 2 nm to 20 nm. In addition, by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, the silver component and the copper component introduced into the gel film are not present as chlorides but are present as some ions. Was recognized. Various performance evaluation tests were performed on this test piece.

(Optical performance evaluation test of rewritable hologram recording material of Example 1)
(1) Ultraviolet-visible absorption spectrum measurement test About the rewritable hologram recording material obtained in Example 1, the absorbance was measured by an ultraviolet-visible absorption spectrum method (UV-vis) having a wavelength of 300 to 800 nm. The measuring device used was V-560 (manufactured by JASCO Corporation).

As measurement samples, four samples (measurement samples a to d) were manufactured by changing the laser irradiation conditions. The measurement sample a is a sample not irradiated with laser light on the test piece prepared in Example 1, and the measurement sample b is blue laser light (405 nm, central irradiation intensity 10 mW / second) on the test piece prepared in Example 1. cm ₂ ) irradiated for 10 minutes, the measurement sample c was irradiated with blue laser light (405 nm, central irradiation intensity 10 mW / cm ² ) for 10 minutes on the test piece prepared in Example 1, and further visible light Irradiation (490-550 nm, central irradiation intensity 14 mW / cm ² ) performed for 10 minutes, measurement sample d is a blue laser beam (405 nm, central irradiation intensity 10 mW / cm) on the test piece prepared in Example 1. ² ) is irradiated for 10 minutes, and further, visible light irradiation (490-550 nm, central irradiation intensity 14 mW / cm ² ) is performed for 30 minutes. The results of the ultraviolet-visible absorption spectrum are shown in (a) to (d) of FIG. In FIG. 2, the light-absorbency characteristics corresponding to each measurement sample are indicated by alphabetical symbols attached to the measurement samples.

  FIG. 2 is a graph showing an absorption spectrum in a range from the ultraviolet region to the visible light region of each measurement sample a to d when blue laser light irradiation and visible light irradiation (490-550 nm) are performed. In this graph, the horizontal axis is wavelength and the vertical axis is absorbance. As is clear from FIG. 2, the absorbance was increased by irradiating the gel film with blue laser light as compared with the case of the measurement sample a in the unirradiated state (solid line indicated by (a) in FIG. 2) ( Solid line shown in FIG. 2 (b)). It was shown that when visible light was further irradiated after the blue laser light irradiation, the absorbance decreased in the range from about 500 nm to 800 nm (broken lines indicated by (c) and (d) in FIG. 2). . As described above, it was confirmed that the absorbance of the gel film was increased by irradiation with blue laser light, and the absorbance was decreased by irradiation with visible light having a wavelength longer than that of blue light.

(2) Stability test against repeated light irradiation After the test piece obtained in Example 1 was irradiated with blue laser light (405 nm, central irradiation intensity 10 mW / cm ² ), the visible light (490 The cycle of irradiation at −550 nm and the central irradiation intensity of 14 mW / cm ² ) was repeated twice, and the measurement was similarly performed by the ultraviolet-visible absorption spectrum method at the end of each cycle.

  Four types of measurement samples were prepared. The measurement sample a, the measurement sample b, and the measurement sample d are the same as those in the ultraviolet-visible absorption spectrum measurement test described above. The measurement sample b ′ was further subjected to blue laser light irradiation for 10 minutes and visible light irradiation for 30 minutes on the test piece prepared in Example 1 under the same conditions as the ultraviolet-visible absorption spectrum measurement test described above. The blue laser light was irradiated for 10 minutes (second blue laser light irradiation). The measurement sample d 'is obtained by further irradiating visible light for 30 minutes under the irradiation conditions of the measurement sample b' (second visible light irradiation). The result is shown in FIG. In FIG. 3, the light-absorbency characteristics corresponding to each measurement sample are indicated by alphabetical symbols attached to the measurement samples.

  FIG. 3 is a graph showing the absorbance characteristics when the test piece prepared in Example 1 is repeatedly irradiated with light. Specifically, in FIG. 3, the absorbance characteristic of the measurement sample a is represented by a solid line indicated by a, the absorbance characteristic of the measurement sample b is represented by a broken line indicated by b, and the absorbance characteristic of the measurement sample b ′ is b. The absorbance characteristic of the measurement sample d is indicated by a solid line indicated by d, and the absorbance characteristic of the measurement sample d ′ is indicated by a broken line indicated by d ′. As is apparent from FIG. 3, the absorbance of the test pieces after the first and second light irradiations was substantially the same, and it was found that coloring and decoloring were repeated with good reproducibility.

(3) Two-beam interference exposure test For the gel film of the test piece obtained in Example 1, after splitting the blue laser light with a beam splitter, two light beams with different polarization directions given by a wave plate are condensed again. Then, a two-beam interference exposure test using a blue laser beam was performed. A very weak red laser (633 nm) was irradiated there, and the transmitted light and first-order diffracted light were detected and the diffraction efficiency was examined. The results are shown in FIG.

  FIG. 4 is a graph showing the time variation of diffraction efficiency during blue laser interference exposure, where the horizontal axis is the exposure time and the vertical axis is the diffraction efficiency. The diffraction efficiency is determined by using diffraction intensity = (Idiff / Itrans) using transmittance intensity (Itrans) and diffracted light intensity (Idiff). The higher the diffraction efficiency, the better the hologram forming ability. Normally, when the diffraction efficiency is 0.1% or more, it can be used as a recording medium for hologram memory.

  As shown in FIG. 4, the diffraction efficiency (Idiff / Itrans) of the test piece obtained in Example 1 gradually increases immediately after the exposure, reaches a maximum value of 0.86% in 1600 seconds, and is very useful as an amplitude hologram. Have a high diffraction efficiency.

  From these results, it was shown that this rewritable hologram recording material is useful as a material for hologram memory.

10 Laser light source (part of laser irradiation means, part of visible light irradiation means)
11 Blue laser (part of laser irradiation means)
12 Red laser (part of visible light irradiation means)

Claims (9)

A hologram is rewritably recorded based on a reversible change from a silver ion or silver halide state to a metallic silver state by a redox reaction,
In a gel having an organic silane compound as a skeleton component, a photosensitive component containing a silver component, a halogen component, and a copper component is provided.
The light-sensitive part is sensitive to light of a specific wavelength, and the absorbance changes as the silver component contained in the gel is reversibly converted from silver ions or silver halide to metallic silver. A rewritable hologram recording material.   The photosensitive part is formed by gelling a sol obtained by hydrolysis in a state where a silver component, a copper component, and a halogen component are mixed with a precursor of an organosilane compound. 2. The rewritable hologram recording material according to claim 1.   The rewritable hologram recording material according to claim 1, wherein the photosensitive portion is formed in a film-like body.   4. The rewritable hologram recording material according to claim 1, wherein the halogen component is one or a plurality of components selected from chlorine, fluorine, bromine and iodine.   The precursor of the organosilane compound is one or more alkoxides selected from trimethoxysilane or triethoxysilane having any of 3-glycidoxypropyl group, vinyl group, phenyl group, ethyl group, and methyl group The rewritable hologram recording material according to claim 1, comprising:   The silver component and the copper component are present in an equivalent amount in the gel of the photosensitive part, and at least a part of each of the silver component and the copper component is dispersed in the gel as halide nanoparticles. The rewritable hologram recording material according to any one of claims 1 to 5. In the method for producing a rewritable hologram recording material in which a hologram is rewritable based on a reversible change from a silver ion or silver halide state to a metallic silver state due to an oxidation-reduction reaction,
A sol preparation step of preparing a sol by performing hydrolysis in a state where a silver component, a copper component and a halogen component are mixed with a precursor of an organosilane compound;
A gel forming step of forming a gel in which a silver component, a halogen component, and a copper component are held using the sol obtained in the sol preparation step;
And a drying step of drying the gel formed in the gel forming step at a temperature of 60 ° C. or less, and the photosensitivity in which absorbance changes in response to irradiation light of a specific wavelength by the gel obtained through the drying step. A method for producing a rewritable hologram recording material, wherein a portion is formed.   The method for producing a rewritable hologram recording material according to claim 7, wherein the sol produced in the sol production step contains an equal amount of a silver component and a copper component. A rewritable hologram recording material manufactured by the rewritable hologram recording material according to any one of claims 1 to 6, or the rewritable hologram recording material according to claim 7 or 8, and
Laser irradiation means for irradiating the rewritable hologram recording material with a two-beam blue laser beam of signal light and reference light;
Hologram reproducing means for reproducing a hologram by irradiating a reference beam from the laser irradiating means to the photosensitive part of the rewritable hologram recording material on which the hologram is recorded by interference exposure by the laser irradiating means,
Visible light irradiating means for irradiating visible light having a longer wavelength than the blue laser light of the laser irradiating means, and recorded on the light sensitive portion of the rewritable hologram recording material by light irradiation by the visible light irradiating means. Hologram recording / reproducing system, wherein the hologram is erased.

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