JP2006235385A - Optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium which has high sensitivity, high diffraction efficiency, satisfactory storage property, low shrinkage rate, dry processing, and multiplex recording characteristic (high recording density), and which prevents the irregular reflection from a reflection layer of the optical information recording medium from being caused by information light, and reference light for recording and reproducing so as to reduce an amount of noise generated into a reproduced image. <P>SOLUTION: The optical information recording medium for recording information by using holography comprises a transparent substrate 1, a recording layer 4 with the information recorded with interference patterns, a filter layer 6 which is disposed between the transparent substrate 12 and the recording layer 4 and transmits the light of a first wavelength and reflects the light of a second wavelength, wherein the recording layer 4 includes an optical refractive index modulation component to record the interference fringes as refractive index modulation by a method of any among (1) a color development reaction, (2) a latent image color development-chromogen self-sensitization amplification color reaction, (3) a latent image color development-chromogen sensitization polymerization reaction, (4) an orientation change of a compound having an intrinsic refractive index, (5) a dye decoloration reaction, and (6) a residual decoloration dye latent image-latent image sensitization polymerization reaction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical information recording medium.

  Holographic recording, in which information is recorded on a recording medium using holography, is generally performed by superimposing light having image information and reference light inside the recording medium, and forming the interference fringes formed at that time on the recording medium. Done by writing. At the time of reproducing the recorded information, the image information is reproduced by diffraction by interference fringes by irradiating the recording medium with reference light.

  As one structure of an optical information recording medium used for this holographic recording, in Patent Document 1, servo pits 3 are provided on a plastic or glass substrate 1 as shown in FIG. The reflective layer 2 is formed by vapor-depositing this film, and the hologram recording layer 4 made of a recording material and the substrate 5 are formed on the reflective layer.

  However, in FIG. 1, not only the servo light (red) but also the information light used for recording, the recording reference light, and the reproduction reference light used for reproduction (both are green) are irradiated on the disk. Thus, the light reaches the reflection layer 2 and is reflected thereby to be emitted from the light incident / exit surface A as return light. Since the reflection layer 2 is not completely flat, part of the light reflected by the reflection layer 2 is irregularly reflected. This irregularly reflected light rides on the reproduction light as scattering noise, and it is very difficult to separate the noise, so there is a problem that the reproduction image cannot be detected well by the CMOS sensor or CCD. is there. Since the servo light is red light, it can be separated from the green information light and the recording / reproducing reference light. Therefore, the scattering noise from the reflective layer 2 becomes a problem when green light is irradiated. It is.

  Even during recording, the information light and the recording reference light reach the reflection layer 2 and are reflected to generate irregularly reflected light, so that the irregularly reflected light and the irradiated information light / recording reference are generated. There is a possibility that another interference pattern is generated together with the light. This interference pattern is unnecessary and may cause noise during reproduction, and there is a problem that the original recording capacity of the recording medium cannot be achieved. If the recording medium is a material that is not sensitive to red, the recording capacity of the recording medium is not affected even if the servo light is slightly diffusely reflected by the reflective layer 2.

On the other hand, the hologram recording material is required to satisfy all of the following requirements.
(1) High sensitivity (2) High resolution (3) High diffraction efficiency of hologram (4) Processing during recording is dry and quick (5) Multiple recording is possible (Wide dynamic range)
(6) Shrinkage after recording is small (7) Hologram preservation is good

  In particular, (1) high sensitivity, (3) high diffraction efficiency, (4) dry processing, (6) low shrinkage after recording, and (7) good storage stability. These are physical properties that are contradictory in chemical terms, and it is extremely difficult to achieve both.

  For example, known volume phase hologram recording materials include a dichromate gelatin system, a bleached silver halide system and a photopolymer system as a write-once system, and a rewritable system as a photorefractive system and a photochromic polymer system. Etc. are known.

However, in these known volume phase hologram recording materials, there is still no material that satisfies all the above requirements, and improvements are desired.
Specifically, for example, the dichromated gelatin method has the advantages of high diffraction efficiency and low noise characteristics, but has extremely poor storage stability, requires wet processing and has low sensitivity, and is suitable for holographic recording applications. Not suitable.
The bleached silver halide method has the advantage of high sensitivity, but requires wet processing, is complicated in bleaching processing, has a problem of large scattering and inferior light resistance, and is suitable for holographic recording applications. After all it is not generally suitable.
Although the photorefractive material has the advantage that it can be rewritten, it has a problem that a high electric field needs to be applied at the time of recording and the record storage stability is poor.
Although the photochromic polymer system represented by azobenzene polymer material has the advantage that it can be rewritten, it has a problem that the sensitivity is very low and the storage stability is poor. For example, in WO 97/44365 [Patent Document 2], a rewritable hologram recording material using refractive index anisotropy and orientation control of an azobenzene polymer (photochromic polymer) is presented. In addition, the quantum yield of azobenzene isomerization is low and the method is accompanied by a change in orientation, so the sensitivity is extremely low. Far from.

Under such circumstances, a dry-processed photopolymer system as disclosed in JP-A-6-43634 [Patent Document 3] has a basic composition of a binder, a radically polymerizable monomer, and a photopolymerization initiator, and a refractive index modulation. In order to improve the refractive index difference, a compound having an aromatic ring or chlorine or bromine is used for either the binder or the radically polymerizable monomer, so that the refractive index difference is obtained. The refractive index difference can be formed by the polymerization proceeding while the monomers gather in the bright portions of the interference fringes and the binder gathers in the dark portions. Therefore, it can be said that it is a relatively practical method that can achieve both high diffraction efficiency and dry processing.
However, compared with the bleached silver halide method, the sensitivity is about 1/1000, heat-fixing treatment of nearly 2 hours is required to increase the diffraction efficiency, and radical polymerization, so polymerization inhibition by oxygen is inhibited. In addition, there is a problem that the diffraction wavelength and angle at the time of reproduction change due to the shrinkage of the recording material after exposure and fixing, and there is a lack of storage stability because the film is soft. Therefore, it cannot withstand use as a holographic recording application.

Here, in general, cationic polymerization, particularly cationic polymerization accompanied by ring opening of an epoxy compound or the like with respect to radical polymerization, gives less rigidity after polymerization and is not hindered by oxygen to give a rigid film. Therefore, some point out that cationic polymerization is more suitable for holographic recording applications.
For example, in JP-A-5-107999 [Patent Document 4] and JP-A-8-16078 [Patent Document 5], a cationically polymerizable compound (monomer or oligomer) is used in place of a binder, and further a sensitizing dye or radical A hologram recording material in which a polymerization initiator, a cationic polymerization initiator, and a radical polymerizable compound are combined is disclosed.
In addition, JP-A-2001-523842 [Patent Document 6], JP-A-11-512847 [Patent Document 7] and the like do not use radical polymerization, and sensitizing dyes, cationic polymerization initiators, cationic polymerizable compounds, and the like. A hologram recording material using only a binder is disclosed.
However, although these cation polymerization methods show improvement in shrinkage rate compared to radical polymerization methods, the contradiction is that the sensitivity is lowered, and in practical use, it is considered to be a big problem in terms of transfer rate. . In addition, the diffraction efficiency is lowered, which is considered to be a problem in terms of S / N ratio and multiple recording.

  As mentioned above, the photopolymer method is a method involving mass transfer, so when considering the application to holographic recording, the storability is good and the sensitivity is reduced if shrinkage is reduced (cation polymerization method). On the other hand, if the sensitivity is improved, storage stability and shrinkage deteriorate (radical polymerization method). Further, in order to improve the recording density of holographic recording, multiplex recording exceeding 50 times, preferably 100 times or more is essential. However, in the photopolymer method, the polymerization involves polymerization with mass transfer. In contrast to the initial recording speed of multiple recording, the recording speed in the latter stage of multiple recording after the polymerization of many compounds has progressed. By controlling this, the exposure amount is adjusted, and a wide dynamic range is achieved. This is a big problem in practical use.

Such problems of high sensitivity, good storage stability, low shrinkage, dry processing dilemma, and multiple recording characteristics (high recording density) are unavoidable as long as the conventional photopolymer system is used. In addition, it is theoretically difficult to satisfy the requirements for holographic recording by the silver halide method, particularly in terms of dry processing.
Therefore, in order to apply the hologram recording material to holographic recording, such problems are drastically solved, especially high sensitivity and low shrinkage, good storage stability, dry processing, multiple recording characteristics (high recording density) Development of a completely new recording method that can satisfy both of these requirements has been strongly desired.

Japanese Patent Laid-Open No. 11-311936 International Publication No. WO97 / 44365 Pamphlet JP-A-6-43634 Japanese Patent Laid-Open No. 5-107999 JP-A-8-16078 Special table 2001-523842 Japanese National Patent Publication No. 11-512847

  The present invention has been made in view of such problems, and its object is to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). Light that can reduce the amount of noise that rides on the reproduced image by using a hologram recording material that can be used, and preventing irregular reflection from the reflective layer of the optical information recording medium by information light and recording / reproducing reference light It is to provide an information recording medium.

The present invention is as follows.
(1) An optical information recording medium for recording information using holography,
A transparent substrate;
A recording layer on which information is recorded by an interference pattern;
A filter layer that is provided between the transparent substrate and the recording layer and transmits light of a first wavelength and reflects light of a second wavelength;
The recording layer has 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction, 3) latent image color development-colored body sensitized polymerization reaction, 4) orientation change of compound having intrinsic birefringence. 5) A photorefractive index modulation component that records interference fringes as refractive index modulation by any one of the method of 5) dye decolorization reaction and 6) residual decolorization dye latent image-latent image sensitization polymerization reaction. Optical information recording medium.
In the above configuration, the filter layer transmits light having a first wavelength (for example, red light) and reflects light having a second wavelength (for example, green light). As a result, light of two types of wavelengths is separated. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

(2) The optical information recording medium according to (1), wherein the transparent substrate has a servo pit pattern.
In the above configuration, the transparent substrate has a servo pit pattern, and a reflective layer is formed on the pattern, so that light of the second wavelength does not reach the reflective layer. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

(3) The optical information recording medium according to (2), wherein the transparent substrate has a reflective surface formed on the servo pit pattern.
(4) The optical information recording medium according to (1), wherein a polarization direction changing layer for polarizing a light changing direction is provided between the recording layer and the filter layer.
(5) The optical information recording medium according to (4), wherein the polarization direction changing layer is a layer formed of a quarter-wave plate.
These configurations can prevent the polarization direction of light from being changed and the generation of a ghost image by a reflection hologram. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

(6) The optical information recording medium according to (1), wherein the filter layer is a layer made of a dichroic mirror.
(7) The optical information recording medium according to (4) or (5), wherein the filter layer is a layer made of cholesteric liquid crystal.
(8) The polarization direction changing layer changes the light of the second wavelength to light of circular polarization in a predetermined direction, and changes the light of the first wavelength to light of polarization other than the circular polarization of the predetermined direction. The optical information recording medium according to (7), characterized in that:
As described above, a layer made of a dichroic mirror or a layer made of cholesteric liquid crystal can be used as the filter layer. In particular, when a layer made of cholesteric liquid crystal is used as a filter layer, the combination with the above-described quarter-wave plate layer is effective. This is because the cholesteric liquid crystal has a property of reflecting circularly polarized light in a predetermined direction and transmitting other light. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

(9) The optical information recording medium according to (3), wherein the reflective surface is a metal reflective film.
(10) The optical information recording medium according to (3), wherein the reflecting surface is a medium surface that reflects light and is additionally recordable or erasable.
As in these configurations, the reflection surface provided on the substrate is basically a metal reflection film, but may be a medium surface that reflects light and is additionally recordable or erasable. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

(11) The optical information recording medium according to (3), wherein a gap layer for smoothing the substrate surface is provided between the filter layer and the reflecting surface.
By providing the gap layer, in addition to smoothing the substrate surface, the size of the hologram recorded in the recording layer can be adjusted. In addition, since a specific refractive index modulation component is used as the recording layer, it is possible to achieve both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). An optical information recording medium that can be provided can be provided.

  According to the present invention, an optical information recording medium using information light and reference light for recording / reproducing is compatible with high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density). It is possible to provide an optical information recording medium that can prevent the irregular reflection from the reflective layer and reduce the amount of noise on the reproduced image.

The present invention will be further described below.
The optical refractive index modulation component (hologram recording material) contained in the recording layer of the optical information recording medium of the present invention includes 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction, and 3) latent image color development. -Interference by any of the following methods: chromogenic sensitization reaction, 4) orientation change of compound having intrinsic birefringence, 5) dye decolorization reaction, 6) residual decolorization dye latent image-latent image sensitization polymerization reaction It is a component that records fringes as refractive index modulation.

The hologram recording material of the present invention is preferably not subjected to wet processing.
The hologram recording material of the present invention is preferably a system that cannot be rewritten. Here, the non-rewritable method is a method of recording by irreversible reaction, and indicates a method in which once recorded data can be stored without being rewritten even if it is overwritten and recorded. Therefore, it is suitable for storing important data that requires long-term storage. However, of course, it is possible to newly record in an area that has not been recorded yet. In that sense, it is generally called “write-once type” or “write-once type”.

The light used for hologram recording of the present invention is preferably any of ultraviolet light, visible light, and infrared light having a wavelength of 200 to 2000 nm, more preferably ultraviolet light or visible light having a wavelength of 300 to 700 nm, and still more preferably. It is visible light of 400 to 700 nm.
Furthermore, the light used for the hologram recording of the present invention is preferably a coherent laser beam (having the same phase and wavelength). The laser used may be any of a solid laser, a semiconductor laser, a gas laser, and a liquid laser. Preferred laser beams include, for example, a 532 nm YAG laser double wave, a 355 nm YAG laser triple wave, and a vicinity of 400 to 415 nm. Semiconductor lasers such as GaN and InGaN, semiconductor lasers such as AlGaInP around 650 to 660 nm, 488 or 515 nm Ar ion laser, 632 or 633 nm He—Ne laser, 647 nm Kr ion laser, 694 nm ruby laser and 636, 634, 538, 534, and 442 nm He—Cd laser.
It is also preferable to use a nanosecond or picosecond order pulse laser.
When the hologram recording material of the present invention is used for an optical information recording medium, YAG of 532 nm
It is preferable to use a semiconductor laser such as a laser double wave, GaN or InGaN laser in the vicinity of 400 to 415 nm, or AlGaInP in the vicinity of 650 to 660 nm.
The wavelength of light used for hologram reproduction is preferably the same or longer than the wavelength of light used for hologram exposure (recording), and more preferably the same.

In the hologram recording material of the present invention, after the hologram exposure, a fixing step may be performed by light, heat, or both.
In particular, when an acid proliferating agent or a base proliferating agent is used in the hologram recording material of the present invention, it is preferable to use heating for fixing from the viewpoint of allowing the acid proliferating agent or the base proliferating agent to function effectively.
In the case of light fixing, the entire area of the hologram recording material is irradiated with ultraviolet light or visible light (non-interference exposure). Preferred examples of the light source used include a visible light laser, an ultraviolet light laser, a carbon arc, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, an LED, and an organic EL.
In the case of thermal fixing, the fixing step is preferably performed at 40 ° C to 160 ° C, more preferably 60 ° C to 130 ° C.
When both photofixing and heat fixing are performed, light and heat may be applied simultaneously, or light and heat may be added separately.

  The refractive index modulation amount at the time of interference fringe recording is preferably 0.00001 to 0.5, and more preferably 0.0001 to 0.3. In addition, it is preferable that the refractive index modulation amount is smaller as the film thickness of the hologram recording material is larger, and it is preferable that the refractive index modulation amount is larger as the film thickness of the hologram recording material is thinner.

The (relative) diffraction efficiency η of the hologram recording material is given by the following equation.
η = Idiff / Io (Formula 1)
Here, Io is the intensity of transmitted light that is not diffracted, and Idiff is the intensity of light that is diffracted (transmission type) or reflected (reflection type). The diffraction efficiency takes any value from 0 to 100%, preferably 30% or more, more preferably 60% or more, and most preferably 80% or more.

The sensitivity of the hologram recording material is generally expressed by the exposure amount per unit area (mJ / cm ² ), and it can be said that the smaller this value, the higher the sensitivity. However, the exposure amount at which time is taken as sensitivity varies depending on documents and patents. When the exposure amount starts recording (refractive index modulation), the exposure amount gives the maximum diffraction efficiency (refractive index modulation). In some cases, the exposure amount giving a diffraction efficiency half that of the maximum diffraction efficiency may be an exposure amount at which the gradient of the diffraction efficiency is maximized with respect to the exposure amount E.
Further, from the Kugelnick's theoretical formula, the refractive index modulation amount Δn for giving a certain diffraction efficiency is inversely proportional to the film thickness d. That is, the sensitivity for giving a certain diffraction efficiency varies depending on the film thickness, and the smaller the refractive index modulation amount Δn is, the thicker the film thickness d is. Therefore, unless conditions such as film thickness are matched, the sensitivity cannot be generally compared.
In the present invention, sensitivity is defined as “exposure amount giving half the maximum diffraction efficiency (mJ / cm ² )”. The sensitivity of the hologram recording material of the present invention, for example, when the film thickness is about 10 to 200 [mu] m, is preferably 2J / cm ² or less, more preferably 1 J / cm ² or less, 500 mJ / cm ² or less More preferably, it is most preferably 200 mJ / cm ² or less.

When the hologram recording material of the present invention is used in a holographic memory as an optical information recording medium, a large amount of two-dimensional digital information (referred to as signal light) is recorded using a spatial light modulation element (SLM) such as DMD or LCD. It is preferable. In order to increase the recording density, it is preferable to use multiplex recording. The multiplex recording method includes multiplex recording such as angle multiplex, phase multiplex, wavelength multiplex, and shift multiplex. It is preferable to use shift multiple recording. Also, a CCD or CMOS is preferably used for reading the reproduced two-dimensional data.

  When the hologram recording material of the present invention is used in a holographic memory as an optical information recording medium, it is essential to perform multiplex recording in order to improve the capacity (recording density). At that time, it is more preferable to perform multiplex recording 10 times or more, more preferably to perform multiplex recording 50 times or more, and most preferably to perform multiplex recording 100 times or more. Further, it is more preferable from the viewpoints of simplifying the recording system, improving the S / N ratio, etc. that the exposure amount during multiple recording can be kept constant throughout the multiple recording.

  When the hologram recording material of the present invention is used for an optical information recording medium, it is preferable that the hologram recording material during storage is stored in a light shielding cartridge. In addition, a light shielding filter capable of cutting a part of the wavelength range of ultraviolet light, visible light, and infrared light other than the recording light and reproduction light wavelengths may be provided on the front surface, back surface, or both surfaces of the hologram recording material. preferable.

  When the hologram recording material of the present invention is used for an optical information recording medium, the optical information recording medium may be disk-shaped, card-shaped, tape-shaped, or any shape.

  The hologram recording material of the present invention and the hologram recording method using the same will be described in detail below.

1) Interference fringe recording by color development reaction In the present invention, the color development reaction indicates a reaction in which the absorption spectrum shape changes in the region of ultraviolet light, visible light and infrared light of 200 to 2000 nm, more preferably In the absorption spectrum, it shows a reaction in which either λmax becomes longer wavelength or ε increases, and more preferably, a reaction in which both occur. Moreover, it is more preferable that the color development reaction occurs in a wavelength region of 200 to 1000 nm, and it is more preferable that the color development reaction occurs in a wavelength region of 300 to 900 nm.

When recording is based on a color development reaction, the hologram recording material of the present invention is preferably
at least,
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state;
2) including a dye precursor that can be a color former whose absorption is increased from the original state and has no absorption at the hologram reproduction light wavelength, and by electron transfer or energy transfer from the sensitizing dye excited state, It is preferable to include an interference fringe recording component capable of recording an interference fringe using refractive index modulation by color development.

Here, the refractive index of the dye generally takes a high value from the vicinity of the linear absorption maximum wavelength (λmax) in a region having a longer wavelength than that, and particularly takes a very high value in a region having a wavelength as long as 200 nm from λmax to λmax, Some dyes have high values exceeding 1.8 and in some cases exceeding 2. On the other hand, organic compounds that are not pigments such as binder polymers usually have a refractive index of about 1.4 to 1.6.
Therefore, it can be seen that coloring the dye precursor by hologram exposure can preferably form not only an absorptivity difference but also a large refractive index difference.
The hologram recording material of the present invention is preferably a phase-type hologram recording material that records interference fringes by refractive index modulation in terms of high diffraction efficiency. That is, at the time of hologram reproduction, it is preferable that the hologram recording material has no absorption or little absorption at the reproduction light wavelength.
Therefore, when the dye precursor of the present invention becomes a color former after hologram exposure, it is preferable that the color precursor does not have absorption at the hologram recording and reproduction wavelength but has absorption at a shorter wavelength side than that. . The sensitizing dye is preferably decomposed during hologram recording or subsequent fixing to lose its absorption and sensitizing functions.

  Furthermore, in order to increase the refractive index modulation and increase the sensitivity and dynamic range, the dye precursor of the present invention has no absorption at the hologram recording and reproduction wavelength after hologram exposure, and from the hologram recording wavelength and the hologram recording wavelength. It is preferable to be a color former having an absorption maximum in a region between wavelengths of 200 nm short wavelength, and to be a color body having an absorption maximum in a region between the hologram recording wavelength and a wavelength of 100 nm short wavelength from the hologram recording wavelength. Is more preferable.

  First, the sensitizing dye that absorbs light and generates an excited state in the hologram exposure of the present invention will be described in detail.

  The sensitizing dye of the present invention preferably generates an excited state by absorbing any of ultraviolet light, visible light, and infrared light having a wavelength of 200 to 2000 nm, more preferably ultraviolet light having a wavelength of 300 to 700 nm. It absorbs light or visible light to generate an excited state, and more preferably absorbs visible light of 400 to 700 nm to generate an excited state.

The sensitizing dye of the present invention is preferably a cyanine dye, squarylium cyanine dye, styryl dye, pyrylium dye, merocyanine dye, benzylidene dye, oxonol dye, azurenium dye, coumarin dye, ketocoumarin dye, styrylcoumarin dye, pyran dye, xanthene dye. Thioxanthene dye, phenothiazine dye, phenoxazine dye, phenazine dye, phthalocyanine dye, azaporphyrin dye, porphyrin dye, fused ring aromatic dye, perylene dye, azomethine dye, anthraquinone dye, metal complex dye, metallocene dye, etc. And more preferably cyanine dyes, squarylium cyanine dyes, pyrylium dyes, merocyanine dyes, oxonol dyes, coumarin dyes, ketocoumarin dyes, styryl coumarin dyes. Pyran dyes, xanthene dyes, thioxanthene dyes, condensed aromatic dyes, metal complex dyes, include metallocene dyes, more preferred are cyanine dyes, merocyanine dyes, oxonol dyes, metal complex dyes, metallocene dyes. As the metal complex dye, a Ru complex dye is particularly preferable, and as the metallocene dye, ferrocenes are particularly preferable.
In addition, “Dye Handbook” (Shin Okawara et al., Kodansha, 1986), “Chemistry of Functional Dye” (Shin Okawara et al., CMC, 1981), “Special Functional Materials” (Chadasaburo Ikemori et al., The dyes and dyes described in CMC, 1986) can also be used as the sensitizing dye of the present invention. The sensitizing dye of the present invention is not limited to these, and any dye and dye that absorbs visible light can be used. These sensitizing dyes can be selected in accordance with the wavelength of the laser serving as a light source according to the purpose of use, and two or more kinds of sensitizing dyes may be used in combination depending on the application.

  Since the hologram recording material is used in a thick film and most of the recording light needs to pass through the film, the addition amount of the sensitizing dye is increased as much as possible by reducing the molar extinction coefficient of the sensitizing dye at the hologram exposure wavelength. It is preferable to increase the sensitivity. The molar extinction coefficient of the sensitizing dye at the hologram exposure wavelength is preferably 1 or more and 10,000 or less, more preferably 1 or more and 5000 or less, further preferably 5 or more and 2500 or less, and more preferably 10 or more and 1000 or less. Most preferred.

The recording wavelength light transmittance of the hologram recording material is preferably 10 to 99%, more preferably 20 to 95%, further preferably 30 to 90%, and 40 to 85%. It is most preferable in terms of diffraction efficiency, sensitivity, and recording density (multiplicity).
Therefore, it is preferable to adjust the molar extinction coefficient and the added molar concentration at the recording wavelength of the sensitizing dye in accordance with the film thickness of the hologram recording material so as to be like that.

  Further, λmax of the sensitizing dye is preferably shorter than the hologram recording wavelength, and more preferably in the range from the same as the hologram recording wavelength to a wavelength shorter than 100 nm.

Further, the molar extinction coefficient at the recording wavelength of the sensitizing dye is preferably 1/5 or less of the molar extinction coefficient of λmax, and more preferably 1/10 or less.
In particular, when the sensitizing dye is an organic dye such as a cyanine dye or a merocyanine dye, it is preferably 1/20 or less, more preferably 1/50 or less, and 1/100 or less. Is most preferred.
Specific examples of the sensitizing dye of the present invention are given below, but the present invention is not limited thereto.

  In the case of a YAG laser double wave with a hologram recording wavelength of 532 nm, the sensitizing dye is particularly preferably a trimethine cyanine dye having a benzoxazole ring, a Ru complex dye, or ferrocenes, such as GaN or InGaN having a wavelength of 400 to 415 nm. In the case of a laser, a monomethine cyanine dye having a benzoxazole ring, a Ru complex dye, and ferrocenes are particularly preferable.

  Other preferred examples of the sensitizing dye of the present invention are described in Japanese Patent Application No. 2004-238427. The sensitizing dye of the present invention is a commercial product, or can be synthesized by a known method.

  As the interference fringe recording component, the following combinations are preferable. About these, the example described in Japanese Patent Application No. 2004-238077 is mentioned preferably as a specific example.

i) A combination comprising at least an acid color-forming dye precursor as a dye precursor and an acid generator. A combination further containing an acid proliferating agent if necessary.
As the acid generator, diaryl iodonium salts, sulfonium salts and sulfonic acid esters are preferable, and the above-described acid generator (cationic polymerization initiator) can be preferably used.
The color former generated from the acid color-formable dye precursor is preferably a xanthene dye, a fluorane dye or a triphenylmethane dye. Particularly preferred specific examples of the acid coloring dye precursor are listed below, but the present invention is not limited thereto.

  In addition, as the acid color-forming dye precursor of the present invention, a cyanine base (leucocyanine dye) that develops color by addition of an acid (proton) is also preferably used. Although the preferable example of a cyanine base is shown below, this invention is not necessarily limited to this.

ii) A combination containing at least a base color-forming dye precursor as a dye precursor, a base generator, and a base proliferating agent as necessary.
As the base generator, the above-mentioned base generator (anionic polymerization initiator) is preferably mentioned, and as the base color-forming dye precursor, dissociable azo dye, dissociable azomethine dye, dissociable oxonol dye, dissociable xanthene dye , Dissociated fluorane dyes, and non-dissociated isomers of dissociated triphenylmethane dyes.
Particularly preferred specific examples of the base color-forming dye precursor are listed below, but the present invention is not limited thereto.

  iii) an organic compound moiety having a function of cleaving a covalent bond by electron transfer or energy transfer with a sensitizing dye excited state, and an organic compound moiety having a characteristic of becoming a color former when covalently bonded and released Contains a covalently bonded compound. A combination further containing a base if necessary. Particularly preferred specific examples are listed below, but the present invention is not limited thereto.

  iv) When a compound that reacts by electron transfer with the sensitizing dye excited state and can change the absorption form is included. So-called electrochromic compounds can be preferably used. Further, it is more preferable to include a binder polymer, and examples of the binder polymer are described later in 3) Latent image color development-interference fringe recording by color development sensitized polymerization reaction, and Japanese Patent Application No. 2004-238077. Preferred examples are given.

2) Latent image color development—Interference fringe recording by self-sensitized amplification color development reaction of color former Preferably, at least a first step of producing a color former that does not absorb the hologram reproduction light wavelength as a latent image by hologram exposure, and its color development Unlike hologram exposure, the body latent image is irradiated with light in the wavelength range where the molar absorption coefficient of the sensitizing dye is 5000 or less, and the colored body is self-sensitized and amplified, thereby recording the interference fringes as refractive index modulation. The hologram recording method is characterized by having two steps and performing them by dry processing, and is preferable in terms of high-speed writing, high S / N ratio reproduction, and the like.

  Here, the “latent image” means “a refractive index difference that is preferably half or less of a refractive index difference formed after the second step” (that is, preferably doubled in the second step). The above-described amplification process is performed), and the refractive index difference image is more preferably 1/5 or less, more preferably 1/10 or less, and most preferably 1/3 or less (that is, the second difference image). The amplification step is more preferably 5 times or more, more preferably 10 times or more, and most preferably 30 times or more.

Here, the second step is preferably light irradiation, heat application, or both, more preferably light irradiation, and the light to be irradiated is the entire surface exposure (so-called solid exposure, blanket exposure, non-image). Wise exposure) is preferable.
Preferred examples of the light source used include a visible light laser, an ultraviolet light laser, an infrared light laser, a carbon arc, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, an LED, and an organic EL. In order to irradiate light in a specific wavelength region, it is also preferable to use a sharp cut filter, a band pass filter, a diffraction grating, or the like as necessary.

Furthermore, as a hologram recording material capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state;
2) Includes a dye precursor that can be a color former that has a longer wavelength than the original state and that has no absorption at the hologram reproduction light wavelength, and moves electrons or energy from the sensitized dye or color former excited state. Interference fringe recording component capable of recording interference fringes using refractive index modulation by color development,
It is preferable to contain.
Preferred examples of the sensitizing dye and the interference fringe recording component are the same as those described in 1) Color development reaction.
In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
In the wavelength range of the light irradiated in the second step, it is preferable that the molar extinction coefficient of the color former is 1000 or more.

The concept of “latent image color development—colored body self-sensitized amplification color reaction system” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. By transferring energy or electrons from the excited state of the sensitizing dye to the interference fringe recording component, the dye precursor contained in the interference fringe recording component is changed to a color former to form a latent image by color development (the first is described above). Process). Next, light in a wavelength region of 350 to 420 nm is irradiated to cause the color former to be absorbed, and the color former is amplified and generated by self-sensitization of the color former (the second step). In the first step, a latent image is not generated so much in the portion that is the interference dark portion, so that the self-sensitizing color reaction hardly occurs in the second step, and as a result, a large refractive index modulation is performed in the interference bright portion and the interference dark portion. Can be formed and recorded as interference fringes. For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  As a specific example of the latent image color development-chromogen self-sensitized amplification color development reaction, an example described in Japanese Patent Application No. 2004-238427 is preferable.

3) Latent Image Coloring—Interference fringe recording by chromogenic sensitization polymerization reaction Preferably, at least a first step of generating a color developing material having no absorption at the wavelength of the hologram reproduction light as a latent image by hologram exposure, and the color forming latent image Hologram recording characterized in that it has a second process of recording an interference fringe as a refractive index modulation by irradiating the image with light having a wavelength different from that of hologram exposure, and recording the interference fringes as refractive index modulation. This method is excellent in high-speed writing and storage stability.
In the second step, a method in which polymerization is caused while self-sensitizing amplification production is performed is also preferable.

Furthermore, as a hologram recording material capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) Absorption becomes longer in wavelength from the original state by transferring electrons or energy from the excited state of the sensitizing dye in the first step or from the excited state of the chromophore in the second step. A group of dye precursors which can be a color former having an absorption in a wavelength region having a molar extinction coefficient of 5000 or less and having no absorption in a hologram reproduction light wavelength;
3) A polymerization initiator capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the sensitizing dye excited state in the first step and from the color former excited state in the second step,
4) a polymerizable compound,
5) binder,
It is preferable to contain.
Preferred examples of the sensitizing dye and the interference fringe recording component are the same as those described in 1) Color development reaction.

  Preferred examples of the polymerization initiator, the polymerizable compound and the binder are described in detail below.

In recording interference fringes by a polymerization reaction, the binder preferably has a refractive index different from that of the polymerizable compound. In order to increase the refractive index modulation, the refractive index difference in the bulk of the polymerizable compound and the binder is preferably large, and the refractive index difference is preferably 0.01 or more, more preferably 0.05 or more. Preferably, it is 0.1 or more.
For this purpose, either the polymerizable compound or the binder contains at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom, and the other one contains them. Preferably not. It does not matter whether the polymerizable compound has a higher refractive index or the binder has a higher refractive index.

The polymerizable compound of the present invention is a radical, acid (Bronsted acid or Lewis acid) or base (Bronsted base or Lewis base) generated by irradiating light to a sensitizing dye (or color former) and a polymerization initiator. ) Is a compound capable of undergoing addition polymerization to be oligomerized or polymerized.
The polymerizable compound of the present invention may be monofunctional or polyfunctional, may be a single component or a multicomponent, and may be a monomer, a prepolymer (eg, a dimer or oligomer), or a mixture thereof, but is a monomer. It is preferable.
The form may be liquid or solid at room temperature, but it is preferably a liquid having a boiling point of 100 ° C. or higher, or a mixture of a liquid monomer having a boiling point of 100 ° C. or higher and a solid monomer. .

The polymerizable compound of the present invention is roughly classified into a polymerizable compound capable of radical polymerization and a polymerizable compound capable of cationic or anionic polymerization.
In the following, for each of the polymerizable compound capable of radical polymerization and the polymerizable compound capable of cationic or anion polymerization, A) refractive index: polymerizable compound> binder, and B) refractive index: binder> polymerizable compound. In particular, examples of preferable polymerizable compounds will be described.

  A) Refractive index: Polymerizable compound> Preferred examples of radical polymerizable compound in the case of binder

  In this case, the radical polymerizable compound preferably has a high refractive index, and the high refractive index radical polymerizable compound of the present invention has at least one ethylenically unsaturated double bond in the molecule, and at least 1 A compound containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred, and a liquid having a boiling point of 100 ° C. or more is preferred.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

  As the high refractive index radical polymerizable monomer, styrene, 2-chlorostyrene, 2-bromostyrene, methoxystyrene, phenyl acrylate, p-chlorophenyl acrylate, 2-phenylethyl acrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2- (p-chlorophenoxy) ethyl acrylate, benzyl acrylate, 2- (1-naphthyloxy) ethyl acrylate, 2,2-di (p-hydroxyphenyl) propane diacrylate or di Methacrylate, di (2-methacryloxyethyl) ether of bisphenol-A, di (2-acryloxyethyl) ether of bisphenol-A, di (2-methacryloxyethyl) ether of tetrachloro-bisphenol-A, tetrabromo-bisphenol Di- (2-methacryloxyethyl) ether of Ru-A, 1,4-benzenediol dimethacrylate, 1,4-diisopropenylbenzene, and the like, more preferably 2-phenoxyethyl acrylate, methacrylic acid 2 -Phenoxyethyl, 2- (p-chlorophenoxy) ethyl acrylate, p-chlorophenyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, bisphenol-A di (2-acryloxyethyl) ether, acrylic acid 2 -(1-naphthyloxy) ethyl and the like.

  Preferred polymerizable compounds are liquids, but they are N-vinyl carbazole, 2-naphthyl acrylate, pentachlorophenyl acrylate, 2,4,6-tribromophenyl acrylate, bisphenol-A diacrylate, 2-acrylate acrylate. It may be used in admixture with (2-naphthyloxy) ethyl and a second solid polymerizable compound such as N-phenylmaleimide.

  B) Refractive index: Preferable example of radically polymerizable compound in the case of binder> polymerizable compound

In this case, the radical polymerizable compound preferably has a low refractive index, and the low refractive index radical polymerizable compound of the present invention has at least one ethylenically unsaturated double bond in the molecule, and further has an aryl group. It is preferable that no aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is contained.
Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.
Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

The low refractive index radical polymerizable monomer is preferably t-butyl acrylate, cyclohexyl acrylate, iso-bornyl acrylate, 1,5-pentanediol diacrylate, ethylene glycol diacrylate, 1,4-butanediol diacrylate, Diethylene glycol diacrylate, hexamethylene glycol diacrylate, 1,3-propanediol diacrylate, decamethylene glycol diacrylate, 1,4-cyclohexyldiol diacrylate, 2,2-dimethylolpropane diacrylate, glycerol diacrylate, trimethylol Propane diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, triethylene glycol diacrylate, trie Lenglycol dimethacrylate, ethylene glycol dimethacrylate, 1,3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, 2,2,4-trimethyl-1,3-propanediol dimethacrylate, pentaerythritol tri Methacrylate, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, 1,5-pentanediol dimethacrylate, diallyl fumarate, acrylic acid 1H, 1H-perfluorooctyl methacrylate, 1H, 1H, 2H, 2H-perfluorooctyl methacrylate, Examples include acrylic acid 1H, 1H, 2H, 2H-perfluorooctyl, 1-vinyl-2-pyrrolidinone, and more preferably decanediol diacrylate, isoacrylate. Examples include bornyl, triethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, ethoxyethoxyethyl acrylate, triacrylate ester of ethoxylated trimethylolpropane, and 1-vinyl-2-pyrrolidine. , Decanediol diacrylate, iso-bornyl acrylate, triethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, ethoxyethoxyethyl acrylate, acrylic acid 1H, 1H-perfluorooctyl, methacrylic acid 1H, 1H, 2H, 2H-perfluorooctyl, 1H, 1H, 2H, 2H-perfluorooctyl acrylate, 1-vinyl-2-pyrrolidine Etc.

  The preferred polymerizable compounds are liquids, but they may be used in admixture with a second solid polymerizable compound monomer such as N-vinylcaprolactam.

  The cationic polymerizable compound of the present invention is a compound that is polymerized by an acid generated by irradiating light to a sensitizing dye and a cationic polymerization initiator. The anionic polymerizable compound of the present invention is a sensitizing dye and an anionic polymerization. It is a compound in which polymerization is initiated by a base generated by irradiating the initiator with light.

The cation polymerizable compound of the present invention is preferably a compound having at least one oxirane ring, oxetane ring, vinyl ether group, styryl group or N-vinyl carbazole moiety in the molecule, more preferably a compound having an oxirane ring moiety. It is.
The anionic polymerizable compound of the present invention is preferably an oxirane ring, an oxetane ring, a vinyl ether group, a styryl group, an N-vinylcarbazole moiety, an ethylenic double bond moiety having an electron-withdrawing substituent, a lactone moiety, a lactam moiety, A compound having at least one cyclic urethane moiety, cyclic urea moiety or cyclic siloxane moiety in the molecule, more preferably a compound having an oxirane ring moiety.

  A) Refractive index: Polymerizable compound> Preferred examples of cationic or anionic polymerizable compound in the case of binder

  In this case, the cation or anion polymerizable compound preferably has a high refractive index, and the high refractive index cation or anion polymerizable compound of the present invention includes at least one oxirane ring, oxetane ring, vinyl ether group, styryl group, N -A compound having a vinylcarbazole moiety in the molecule and further containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred, and at least one aryl group It is preferable to contain. Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

  Preferred as a high refractive index cationic or anionic polymerizable monomer having an oxirane ring is phenyl glycidyl ether, phthalic acid diglycidyl ester, trimellitic acid triglycidyl ester, resorcin diglycidyl ether, dibromophenyl glycidyl ether, dibromoneopentyl glycol diglycidyl ether 4,4′-bis (2,3-epoxypropoxyperfluoroisopropyl) diphenyl ether, p-bromostyrene oxide, bisphenol-A-diglycidyl ether, tetrabromobisphenol-A-diglycidyl ether, bisphenol-F-diglycidyl Ether, 1,3-bis (3 ′, 4′-epoxycyclohexyl) ethyl) -1,3, -diphenyl-1,3, -dimethyldisiloxane And the like.

  Specific examples of the high refractive index cation or anion polymerizable monomer having an oxetane ring include compounds in which the oxirane ring in the specific examples of the high refractive index cation or anion polymerizable monomer having an oxirane ring is replaced with an oxetane ring. It is done.

  Specific examples of the high refractive index cation or anion polymerizable monomer having a vinyl ether group moiety include, for example, vinyl-2-chloroethyl ether, 4-vinyl ether styrene, hydroquinone divinyl ether, phenyl vinyl ether, bisphenol A divinyl ether, and tetrabromobisphenol A. Examples thereof include divinyl ether, bisphenol F divinyl ether, phenoxyethylene vinyl ether, and p-bromophenoxyethylene vinyl ether.

  In addition, styrene monomers such as styrene, 2-chlorostyrene, 2-bromostyrene, methoxystyrene, and N-vinylcarbazole are also preferable as the high refractive index cationic polymerizable monomer.

  B) Refractive index: Preferable example of cationic or anionic polymerizable compound in the case of binder> polymerizable compound

  In this case, the cation or anion polymerizable compound preferably has a low refractive index, and the low refractive index cation or anion polymerizable compound of the present invention has at least one oxirane ring, oxetane ring, or vinyl ether group in the molecule. Furthermore, a compound containing no aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred. Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

Specific examples of the low refractive index cationic or anionic polymerizable monomer having an oxirane ring include glycerol diglycidyl ether, glycerol triglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane triglycidyl ether, 1,6-hexanediol. Diglycidyl ether, ethylene glycol diglycidyl ether, ethylene glycol monoglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, adipic acid diglycidyl ester, 1,2,7,8-diepoxyoctane, 1, 6-dimethylol perfluorohexane diglycidyl ether, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3 ′, 4 ′ Epoxycyclohexanecarboxylate, 3,4-epoxycyclohexyloxirane, bis (3,4-epoxycyclohexyl) adipate, 2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane, 2,2-bis [ 4- (2,3-epoxypropoxy) cyclohexyl] hexafluoropropane, 2- (3,4-epoxycyclohexyl) -3 ′, 4′-epoxy-1,3-dioxane-5-spirocyclohexane, 1,2- Ethylenedioxy-bis (3,4-epoxycyclohexylmethane), ethylene glycol-bis (3,4-epoxycyclohexanecarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, di-2,3-epoxy Cyclopentyl ether, vinyl glycidyl Ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, 1,3-bis (3 ', 4'-epoxycyclohexyl) ethyl) -1,1,3,3, - tetramethyl disiloxane and the like.

  Specific examples of the low refractive index cation or anion polymerizable monomer having an oxetane ring include compounds in which the oxirane ring in the specific examples of the low refractive index cation or anion polymerizable monomer having an oxirane ring is replaced with an oxetane ring. It is done.

  Specific examples of the low refractive index cationic or anionic polymerizable monomer having a vinyl ether group moiety include, for example, vinyl-n-butyl ether, vinyl t-butyl ether, ethylene glycol divinyl ether, ethylene glycol monovinyl ether, propylene glycol divinyl ether, neo Pentyl glycol divinyl glycol, glycerol divinyl ether, glycerol trivinyl ether, triethylene glycol divinyl ether, trimethylolpropane monovinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, allyl vinyl ether, 2,2-bis (4-cyclohexanol ) Propane divinyl ether, 2,2-bis (4-cyclohexanol) trifluoro Propane divinyl ether.

  Next, preferred binders in the present invention at the time of interference fringe recording by polymerization reaction are divided into the case of A) refractive index: polymerizable compound> binder and B) refractive index: binder> polymerizable compound. An example will be described.

  A) Preferred examples of binders in the case of refractive index: polymerizable compound> binder.

In this case, the binder preferably has a low refractive index, and is preferably a binder containing no aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom, or sulfur atom.
Specific examples of preferred low refractive index binders include acrylate and alpha-alkyl acrylate esters and acidic polymers and interpolymers (eg, polymethyl methacrylate and polyethyl methacrylate, methyl methacrylate and other (meth) acrylic acid alkyl esters). Copolymers), polyvinyl esters (eg, polyvinyl acetate, polyacetic acid / vinyl acrylate, polyacetic acid / vinyl methacrylate and hydrolyzable polyvinyl acetate), ethylene / vinyl acetate copolymers, saturated and unsaturated polyurethanes, Butadiene and isoprene polymers and copolymers and polyglycol high molecular weight poly (ethylene oxide) having an average molecular weight of approximately 4,000 to 1,000,000, epoxides (e.g. Product), polyamide (for example, N-methoxymethyl polyhexamethylene adipamide), cellulose ester (for example, cellulose acetate, cellulose acetate succinate and cellulose acetate butyrate), cellulose ether (for example, methyl cellulose, ethyl cellulose, ethyl benzyl cellulose) ), Polycarbonate, polyvinyl acetal (for example, polyvinyl butyral and polyvinyl formal), polyvinyl alcohol, polyvinyl pyrrolidone, and the like.

A fluorine atom-containing polymer is also preferable as the low refractive index binder. Preferably, fluoroolefin is an essential component, and one or more selected from alkyl vinyl ether, alicyclic vinyl ether, hydroxy vinyl ether, olefin, haloolefin, unsaturated carboxylic acid and ester thereof, and carboxylic acid vinyl ester It is a polymer soluble in an organic solvent having the unsaturated monomer as a copolymerization component. Preferably, the mass average molecular weight is 5,000 to 200,000, and the fluorine atom content is 5 to 70% by mass.

  Specific examples of the aforementioned fluorine atom-containing polymer include, for example, an organic solvent-soluble “Lumiflon” series having a hydroxyl group (for example, Lumiflon LF200, mass average molecular weight: about 50,000, manufactured by Asahi Glass Co., Ltd.). In addition, organic solvent-soluble fluorine atom-containing polymers are also marketed by Daikin Industries, Ltd., Central Glass Co., Ltd., and Penwort Co., Ltd., and these can also be used.

In addition, preferred examples include silicon compounds such as poly (dimethylsiloxane) and silicon oils not containing aromatics.
In addition, an epoxy oligomer compound containing no aromatic can also be used as a low refractive index reactive binder.

  B) Refractive index: A preferred example of a binder in the case of binder> polymerizable compound.

In this case, the binder preferably has a high refractive index, and is preferably a binder containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom, or sulfur atom. More preferably, the binder contains.
Specific examples of preferable high refractive index binders include polystyrene polymers and copolymers such as acrylonitrile, maleic anhydride, acrylic acid, methacrylic acid and esters thereof, and vinylidene chloride copolymers (eg, vinylidene chloride / acrylonitrile copolymer). Polymer, vinylidene chloride / methacrylate copolymer, vinylidene chloride / vinyl acetate copolymer), polyvinyl chloride and copolymers (eg, polyvinyl chloride / acetate, vinyl chloride / acrylonitrile copolymer), polyvinyl benzal synthetic rubber (For example, butadiene / acrylonitrile copolymer, acrylonitrile / butadiene / styrene copolymer, methacrylate / acrylonitrile / butadiene / styrene copolymer, 2-chlorobutadiene-1,3 polymer, chlorinated rubber, On / butadiene / styrene, styrene / isoprene / styrene block copolymer), copolyesters (e.g., formula HO (CH ₂₎ polymethylene glycol nOH (n in the formula is an integer of 2 to 10) and, ( 1) produced from reaction products of hexahydroterephthalic acid, sebacic acid and terephthalic acid, (2) terephthalic acid, isophthalic acid and sebacic acid, (3) terephthalic acid and sebacic acid, (4) terephthalic acid and isophthalic acid And (5) mixtures of the glycols and (i) terephthalic acid, isophthalic acid and sebacic acid and (ii) copolyesters made from terephthalic acid, isophthalic acid, sebacic acid and adipic acid), poly N-vinylcarbazole And its copolymer, polycarbonate comprising carbonate and bisphenol Such as over doors and the like.

Preferable examples include poly (methylphenylsiloxane), silicon compounds such as 1,3,5-trimethyl-1,1,3,5,5-pentaphenyltrisiloxane, silicon oil containing a large amount of aromatics, and the like. .
In addition, an epoxy oligomer compound containing a large amount of aromatics can also be used as a high refractive index reactive binder.

The polymerization initiator used for interference fringe recording by the polymerization reaction of the present invention is preferably a ketone, organic peroxide, trihalomethyl-substituted triazine, diazonium salt, diaryliodonium salt, sulfonium salt, borate Radical polymerization of diaryl iodonium organoboron complex, sulfonium organoboron complex, cationic sensitizing dye organoboron complex, anionic sensitizing dye onium salt complex, metal arene complex, sulfonate ester An agent (radical generator) and a cationic polymerization initiator (acid generator), or those having both functions are mentioned.

  At that time, it is also preferable to use an acid proliferating agent from the viewpoint of high sensitivity. Specific examples of preferred acid proliferating agents include those described in Japanese Patent Application No. 2003-182849.

  Further, it is also preferable to use anionic polymerization and an anionic polymerization initiator (base generator). In that case, it is also preferable to use a base proliferating agent from the viewpoint of high sensitivity. In these cases, specific examples of preferred anionic polymerization initiators and base proliferating agents include those described in Japanese Patent Application No. 2003-178083.

  Specific examples of preferred polymerization initiators, polymerizable compounds and binders of the present invention include those described in Japanese Patent Application No. 2004-238392.

  Specific examples of preferred polymerization initiators in the present invention are listed below, but the present invention is not limited thereto.

In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
In the wavelength range of the light irradiated in the second step, it is more preferable that the molar extinction coefficient of the color former is 1000 or more.

  In the hologram recording material of the present invention, it is preserved that the sensitizing dye is decomposed and fixed by either the first step, the second step, or the subsequent fixing step by light irradiation, heat application, or both. From the viewpoint of the property and non-destructive regeneration, and further, the sensitizing dye is added by either the first step, the second step, or the fixing step by subsequent light irradiation, heat application, or both. More preferably, the colored body is decomposed and fixed by either the process or the fixing process by light irradiation, heat application, or both.

The concept of “latent image color development-colored material sensitized polymerization reaction system” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. By transferring energy or electrons from the excited state of the sensitizing dye to the interference fringe recording component, the dye precursor contained in the interference fringe recording component is changed to a color former to form a latent image by color development (the first is described above). Process). Next, light in the wavelength region of 350 to 420 nm is irradiated to cause the color former to be absorbed, and the polymerization initiator is activated by electron transfer or energy transfer to initiate polymerization. For example, when the polymerizable compound has a higher refractive index than the binder, the refractive index increases because the polymerizable compound collects in the portion where the polymerization occurs (second step). In the first step, the latent image is not generated so much in the portion that is the interference dark portion, so polymerization does not occur much in the second step, and the abundance ratio of the binder is high, and as a result, the refraction is large in the interference bright portion and the interference dark portion Rate modulation can be formed and recorded as interference fringes. If the sensitizing dye and the color-developing material can be decomposed and decolored by the first and second steps, or the subsequent fixing step, a hologram recording material excellent in nondestructive reproduction and storage stability can be provided.
For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  Preferable examples of the latent image color development-chromogen sensitized polymerization reaction include those described in Japanese Patent Application No. 2004-238392.

4) Interference fringe recording by change in orientation of compound having intrinsic birefringence Preferably, the orientation change of the compound having intrinsic birefringence is caused by hologram exposure and is fixed as it is by a chemical reaction so that it cannot be rewritten. An interference fringe recording is performed as refractive index modulation. As the compound having an intrinsic birefringence, a liquid crystal compound is preferable, a low molecular liquid crystal compound is more preferable, and a low molecular liquid crystal compound having a polymerizable group is further preferable. The low molecular liquid crystalline compound having a polymerizable group is preferably a nematic liquid crystalline compound, a smectic liquid crystalline compound, a discotic nematic liquid crystalline compound, a discotic liquid crystalline compound, or a cholesteric liquid crystalline compound, and has a nematic liquid crystalline property. Or it is more preferable that it is smectic liquid crystallinity.
Further, in the hologram recording material in the interference fringe recording method by the orientation change of the compound having an intrinsic birefringence, it is preferable to have at least a low molecular liquid crystalline compound having a polymerizable group, a photoreactive compound, a polymerization initiator, It is also preferable to have a sensitizing dye, a binder polymer and the like. Preferred examples of the polymerization initiator, sensitizing dye, binder polymer and the like are as described above.
The photoreactive compound is preferably a photoisomerization compound, more preferably an azobenzene compound, a stilbene compound, a spiropyran compound, a spirooxazine compound, a diarylethene compound, a fulgide compound, a fulgimide compound, or cinnamic acid. Compound, a coumarin compound, or a chalcone compound, most preferably an azobenzene compound.
The photoreactive compound may be a low molecular compound or a polymer compound. When the photoreactive compound is a polymer compound, it is preferably a polymer compound in which a photoreactive site is pendant.
As a specific example of the interference fringe recording method and material based on the orientation change of the compound having an intrinsic birefringence, an example described in Japanese Patent Application No. 2003-327594 is preferable.

5) Dye-decoloring reaction Preferably, it has at least one or more decolorable dyes, and the decoloring dyes form interference fringes by refractive index modulation using decoloring by hologram exposure. And a hologram recording method.

  In the present invention, the decolorizable dye has absorption in the ultraviolet, visible and infrared regions of 200 to 2000 nm, and λmax is shortened directly or indirectly by light irradiation, and the molar absorption of absorption. The generic name of the dye that causes any decrease in the coefficient is shown, and more preferably, the dye causes both. Moreover, it is more preferable that the decoloring reaction occurs in a wavelength region of 200 to 1000 nm, and it is further preferable that the decoloring reaction occurs in a wavelength region of 300 to 900 nm.

As a preferable combination,
(A) The decolorizable dye is a sensitizing dye that absorbs at the hologram exposure wavelength, and forms interference fringes by refractive index modulation using absorbing the light during the hologram exposure and decoloring itself as a result. And a hologram recording method.
(B) A sensitizing dye having absorption at least at the hologram exposure wavelength and a decolorizable dye having a molar extinction coefficient of 1000 or less, preferably 100 or less, at the hologram reproduction light wavelength. A hologram recording method comprising forming interference fringes by refractive index modulation using absorption and decolorization of a decolorizable dye by electron transfer using the excitation energy or energy transfer.
The method (B) is more preferable.

  Furthermore, it has a decoloring agent precursor that is different from the decoloring dye and sensitizing dye, and after the sensitizing dye or decoloring dye generates an excited state by hologram exposure, energy transfer with the decoloring agent precursor Alternatively, the decoloring agent is generated from the decoloring agent precursor by electron transfer, and the decoloring agent forms an interference fringe by refractive index modulation using decoloring the decoloring dye. A hologram recording method is also preferable. In that case, the decolorizer is preferably any one of radical, acid, base, nucleophile, electrophile, and singlet oxygen. Therefore, the decolorizer precursor is a radical generator, acid generator, base. It is preferably any of a generator, a nucleophile generator, an electrophile generator, and triplet oxygen. The decoloring precursor is more preferably any of a radical generator, an acid generator and a base generator.

  In any case, it is more preferable to further include a binder polymer, and examples of the binder polymer include the binder polymers described above.

Next, in the “dye decoloring reaction method”, a decolorizable dye for forming a difference in refractive index between the interference fringe bright part and the dark part will be described in detail.
In the above-described method (A), since both the sensitizing dye and the decoloring dye are used, a preferred example of the decoloring dye includes the above-described examples of the sensitizing dye. It is preferable that λmax of the sensitizing dye / decolorizable dye is between the hologram recording light wavelength and the wavelength region shorter by 100 nm from the hologram recording light wavelength.

  On the other hand, in the above-described method (B), a decolorizable dye is used separately from the sensitizing dye. In that case, the decolorizable dye preferably has a molar extinction coefficient of the hologram recording light wavelength of 1000 or less, more preferably 100 or less, and most preferably 0. The λmax of the decolorizable dye is preferably between the hologram recording light wavelength and a wavelength region shorter by 200 nm from the hologram recording light wavelength.

  In the method (B), the decolorizable dye is preferably a cyanine dye, squarylium cyanine dye, styryl dye, pyrylium dye, merocyanine dye, benzylidene dye, oxonol dye, coumarin dye, pyran dye, xanthene dye, thiol. Xanthene dye, phenothiazine dye, phenoxazine dye, phenazine dye, phthalocyanine dye, azaporphyrin dye, porphyrin dye, condensed ring aromatic dye, perylene dye, azomethine dye, azo dye, anthraquinone dye, metal complex dye More preferably, any of a cyanine dye, a styryl dye, a merocyanine dye, a benzylidene dye, an oxonol dye, a coumarin dye, a xanthene dye, an azomethine dye, an azo dye, and a metal complex dye.

In particular, when the decolorizer is an acid, the decolorizable dye is preferably a dissociated benzylidene dye, a dissociated oxonol dye, a dissociable xanthene dye, a dissociated form of a dissociable azo dye, a dissociable benzylidene dye, More preferred is a dissociated oxonol dye or dissociated azo dye. Here, the dissociation type dye has an active hydrogen having a pKa in the range of about 2 to 14 such as —OH group, —SH group, —COOH group, —NHSO ₂ R group, —CONHSO ₂ R group, etc. Is a general term for dyes whose absorption becomes longer or higher ε due to dissociation. Therefore, if the dissociated dye is treated with a base in advance to obtain a dissociated dye, a dye having a long wavelength or a high ε can be prepared in advance, and it can be changed to a non-dissociated form by photoacid generation and decolored (short wavelength). Or low ε).

  In particular, when the decolorizer is a base, if an acid color-developing dye color former such as triphenylmethane dye, xanthene dye, or fluorane dye previously treated with an acid as a color former is used as the decoloring dye, It becomes possible to change to an aprotic adduct by generating a base and decolorize (shorter wavelength or lower ε).

  Specific examples of the decolorizable dye of the present invention are given below, but the present invention is not limited thereto.

Further, as the decolorizable dye of the present invention, the following examples of decolorizable dyes that can be decolored as a result of bond breakage due to electron transfer from the excited state of the sensitizing dye generated by hologram exposure are also preferable. Can be mentioned.
Although these decolorizable dyes are originally cyanine dyes, they are changed to cyanine bases (leucocyanine dyes) due to bond breakage due to electron transfer, and decoloration or shortening of absorption occurs.

  When the decolorizer precursor is an acid generator, preferred examples include the above-described cationic polymerization initiators. In the case of a radical generator, preferred examples include the aforementioned radical polymerization initiators. In the case of a base generator, preferred examples include the aforementioned anionic polymerization initiators.

  Preferable examples of the dye decoloring reaction include those described in Japanese Patent Application No. 2004-88790.

6) Residual decolorizable dye latent image-latent image sensitized polymerization reaction Preferably, a sensitizing dye having absorption at the hologram exposure wavelength absorbs light during hologram exposure to generate an excited state, and then uses the excitation energy. A first step of erasing a decolorizable dye having a molar extinction coefficient of a hologram reproduction light wavelength of 1000 or less, preferably 100 or less, and most preferably 0, and using a remaining decolorizable dye as a latent image. And a second step of recording the interference fringes as refractive index modulation by irradiating the residual decolorizable dye latent image with light having a wavelength different from that of the hologram exposure. This method is excellent in high-speed recording, suitability for multiple recording, storability after recording, and the like.
Further, after the sensitizing dye having absorption at the hologram exposure wavelength absorbs light at the time of hologram exposure to generate an excited state, the decolorizer is transferred by energy transfer or electron transfer with the decolorizer precursor described in 5). A decoloring agent is generated from the precursor, and the decoloring agent decolorizes the decolorizable dye, whereby a first step of forming a residual decolorable dye that has not been decolored as a latent image, and the residual decoloration By irradiating the chromatic dye latent image with light having a wavelength different from that of hologram exposure, the polymerization initiator is activated by energy transfer or electron transfer to cause polymerization, and the interference fringes are recorded as refractive index modulation. A hologram recording method characterized by having a step is also preferable.

Further, as a compound group capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) Hologram reproduction light that can be decolored as a result of direct electron transfer from the excited state of the sensitizing dye in the first step or as a result of generating a decolorant by electron transfer to the decolorizer precursor. A decolorizable dye having a molar extinction coefficient of 1000 or less,
3) A decolorizer precursor of a polymerization initiator (possibly 2) capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the remaining decolorizable dye excited state in the second step. )
4) a polymerizable compound,
5) binder,
It is preferable to contain. In the case of energy transfer or electron transfer to the decolorizer precursor in 2), 6) the decolorizer is generated by electron transfer or energy transfer from the sensitizing dye excited state in the first step. It is also preferred to include a decolorant precursor that can be used.

Preferred examples of the sensitizing dye are the same as those described in 1) Color development reaction. Preferred examples of the polymerization initiator, the polymerizable compound and the binder are the same as those described in the section of 3) Latent image color development-coloring body sensitization polymerization reaction.
Preferred examples of the decolorizable dye and decolorant precursor are the same as those described in 5) Decolorization reaction.
In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
Moreover, it is preferable that the molar extinction coefficient of the decolorizable dye is 1000 or more in the wavelength range of the light irradiated in the second step.

Here, in the “residual decoloring dye latent image-latent image sensitization polymerization method” of the present invention, it is also preferable that the decoloring agent precursor and the polymerization initiator are partially or entirely the same and serve both functions.
When a decolorizable dye is added separately from the sensitizing dye and the decolorizer precursor and the polymerization initiator are different (for example, the decolorizer precursor is an acid generator or a base generator, the polymerization initiator is a radical Polymerization initiator or decolorizer precursor is radical generator or nucleophile generator, polymerization initiator is acid generator or base generator), sensitizing dye is electron only to decolorizer precursor It is preferable that transfer sensitization is possible and the polymerization initiator is capable of electron transfer sensitization only with a decolorizable dye.

  In the hologram recording method of the present invention and the hologram recording material capable of such recording, either by the first step, the second step, or the subsequent fixing step by light irradiation, heat application, or both. Decomposing and fixing the sensitizing dye is preferable in terms of storage stability and non-destructive regeneration, and further, a fixing step by the first step, the second step, or subsequent light irradiation, heat application, or both. It is more possible to decompose and fix the decolorizable dye remaining in either the second step or the fixing step by the subsequent light irradiation, heat application, or both. preferable.

The concept of “residual decoloring dye latent image-latent image sensitized polymerization reaction method” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. The decoloring agent is generated by causing energy transfer or electron transfer from the excited state of the sensitizing dye to the decoloring agent precursor to decolorize the decoloring dye. As a result, it is possible to form a latent image with the remaining decolorizable dye (first step). Next, light in the wavelength region of 350 to 420 nm is irradiated to cause absorption of the residual decolorizable dye latent image, and the polymerization initiator is activated by electron transfer or energy transfer to initiate polymerization. For example, when the polymerizable compound has a refractive index lower than that of the binder, the refractive index is lowered because the polymerizable compound is collected at the portion where the polymerization occurs (second step). In the portion where the interference bright portion is formed in the first step, there is little residual decolorizable dye that becomes a latent image, so that polymerization does not occur so much in the second step and the abundance ratio of the binder becomes high. A large refractive index modulation can be formed in the interference dark part, and recording can be performed as interference fringes. If the sensitizing dye and the remaining decolorizable dye can be decomposed and decolored by the first and second steps or further fixing step, a hologram recording material excellent in nondestructive reproduction and storage stability can be provided. .
For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  Preferred examples of the residual decolorizable dye latent image-latent image sensitization polymerization reaction include the examples described in Japanese Patent Application No. 2004-88790.

  In addition to the sensitizing dye, the interference fringe recording component, the polymerization initiator, the polymerizable compound, the binder, the decoloring dye, the decoloring agent precursor, etc. In addition, additives such as an electron donating compound, an electron accepting compound, a chain transfer agent, a crosslinking agent, a heat stabilizer, a plasticizer, and a solvent can be used.

Electron-donating compounds have the ability to reduce radical cations of sensitizing dyes, color formers or decolorizable dyes, and electron-accepting compounds have the ability to oxidize radical anions of sensitizing dyes, color formers or decolorable dyes. Both have a function of regenerating a sensitizing dye, a color former or a decolorizable dye. Specifically, for example, an example described in Japanese Patent Application No. 2004-238077 is given as a preferred example.
In particular, the electron donating compound is useful for high sensitivity because it can quickly regenerate the sensitizing dye, the color former or the decolorable dye radical cation after the electron transfer to the dye precursor group. As the electron donating compound, those having an oxidation potential lower than the oxidation potential of the sensitizing dye, color former or decolorizable dye are preferable. Preferred specific examples of the electron donating compound are listed below, but the present invention is not limited thereto.

  Especially as an electron-donating compound, a phenothiazine type compound (for example, 10-methylphenothiazine, 10- (4′-methoxyphenyl) phenothiazine), a triphenylamine type compound (for example, triphenylamine, tri (4′-methoxyphenyl) amine) , TPD compounds (such as TPD) are preferred, phenothiazine compounds are more preferred, and N-methylphenothiazine is most preferred.

The sensitizing dye, acid generator, base generator, dye precursor, decolorizable dye, decolorant precursor, electron donating compound, etc. of the present invention described above may be oligomers or polymers. It may be contained in the main chain or in the side chain, and may be a copolymer.
The polymer main chain may have any structure, and preferred examples include polyacrylates, polymethacrylates, polyethers such as polystyrene and polyethylene oxide, polyesters, polyamides, and the like.
In this case, the polymer or oligomer of the present invention has a repeating unit of 2 to 1,000,000, preferably 3 to 1,000,000, more preferably 5 to 500,000, and most preferably 100,000 to 100,000. It is as follows.
The molecular weight of the polymer or oligomer is preferably 500 or more and 10 million or less, more preferably 1000 or more and 5 million or less, further preferably 2000 or more and 1 million or less, and most preferably 3000 or more and 1 million or less. .

  Specific examples of the chain transfer agent, the crosslinking agent, the heat stabilizer, the plasticizer, the solvent, and the like include the examples described in Japanese Patent Application No. 2004-238392.

The chain transfer agent is preferably a thiol, such as 2-mercaptobenzoxazole, 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, 4-methyl-4H-1,2,4-triazole-3-thiol, Examples include p-bromobenzenethiol, thiocyanuric acid, 1,4-bis (mercaptomethyl) benzene, p-toluenethiol and the like.
In particular, when the polymerization initiator is 2,4,5-triphenylimidazolyl dimer, it is preferable to use a chain transfer agent.

A heat stabilizer can be added to the hologram recording material of the present invention in order to improve storage stability during storage.
Useful heat stabilizers include hydroquinone, phenidone, p-methoxyphenol, alkyl and aryl substituted hydroquinones and quinones, catechol, t-butylcatechol, pyrogallol, 2-naphthol, 2,6-di-t-butyl-p. -Cresol, phenothiazine, chloranneal and the like.

  The plasticizer is used to change the adhesiveness, flexibility, hardness, and other mechanical properties of the hologram recording material. Examples of the plasticizer include triethylene glycol dicaprylate, triethylene glycol bis (2-ethylhexanoate), tetraethylene glycol diheptanoate, diethyl sebacate, dibutyl suberate, tris (2-ethylhexyl) phosphate, Examples include tricresyl phosphate, dibutyl phthalate, alcohols, and phenols.

The hologram recording material of the present invention may be prepared by a usual method.
For example, as a method for forming a hologram recording material of the present invention, the binder and each component may be dissolved in a solvent and applied using a spin coater or a bar coater.
In that case, preferably as a solvent, for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol diacetate, ethyl lactate, cellosolve acetate, cyclohexane, toluene, Hydrocarbon solvents such as xylene, ether solvents such as tetrahydrofuran, dioxane, diethyl ether, cellosolv solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethyl cellosolve, methanol, ethanol, n-propanol, 2-propanol, n- Alcohol solvents such as butanol and diacetone alcohol, fluorine solvents such as 2,2,3,3-tetrafluoropropanol, dichloromethane, chloroform , 1,2-halogenated hydrocarbon solvents such as dichloroethane, N, amide solvents such as N- dimethylformamide, acetonitrile, and nitrile-based solvents such as propionitrile.

The hologram recording material of the present invention can be applied directly on the substrate by using a spin coater, roll coater or bar coater, or can be cast as a film and laminated on the substrate by a usual method. It can be a hologram recording material.
Here, “substrate” means any natural or synthetic support, preferably one that can exist in the form of a flexible or rigid film, sheet or plate.
The substrate is preferably polyethylene terephthalate, resin-undercoated polyethylene terephthalate, polyethylene terephthalate treated with flame or electrostatic discharge, cellulose acetate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, glass or the like.
The solvent used can be removed by evaporation during drying. Heating or reduced pressure may be used for evaporation removal.

The hologram recording material of the present invention may be formed by melting a binder containing each component at a temperature equal to or higher than the glass transition temperature or the melting point of the binder and then subjecting it to melt extrusion or injection molding. At that time, a reactive cross-linking binder may be used as the binder, and the film may be cured by cross-linking after extrusion or molding to increase the film strength. In that case, radical polymerization reaction, cationic polymerization reaction, condensation polymerization reaction, addition polymerization reaction and the like can be used for the crosslinking reaction. In addition, methods described in JP 2000-250382 A, JP 2000-172154 A, and the like can also be preferably used.
In addition, a method in which each component is dissolved in a monomer solution forming a binder and then the monomer is thermally polymerized or photopolymerized to form a polymer, which is preferably used as a binder. As a polymerization method at that time, a radical polymerization reaction, a cationic polymerization reaction, a condensation polymerization reaction, an addition polymerization reaction, or the like can be used.

  Furthermore, a protective layer for blocking oxygen may be formed on the hologram recording material. The protective layer is made of a plastic film or plate such as polyolefin such as polypropylene or polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate or cellophane film by electrostatic adhesion or lamination using an extruder. Alternatively, the polymer solution may be applied. Further, a glass plate may be bonded. Further, an adhesive or a liquid substance may be present between the protective layer and the photosensitive film and / or between the base material and the photosensitive film in order to improve airtightness.

When the hologram recording material of the present invention is used for holographic optical memory, it is more preferable that the hologram recording material does not shrink before and after hologram recording from the viewpoint of improving the S / N ratio during signal reproduction.
Therefore, for example, an expansion agent described in JP-A-2000-86914 is used for the hologram recording material of the present invention, or a shrink-resistant binder described in JP-A-2000-250382, 2000-172154, and JP-A-11-344917 is used. It is also preferable to use it.
In addition, it is also preferable to adjust the interference fringe interval by using a diffusing element described in JP-A-3-46687, 5-204288, JP-A-9-506441 and the like.

In known ordinary photopolymers such as Patent Documents 3 and 4, when multiple recording is performed, in the latter half of the multiple recording, the polymerization is recorded at a considerably advanced position. Therefore, compared to the first half of the multiple recording, Even when the same signal is recorded, an exposure time is required (sensitivity decreases), which is a serious problem in system design. That is, the range in which the refractive index modulation amount increases linearly with respect to the exposure amount is very narrow.
In contrast, the recording methods of 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction, and 5) dye decolorization reaction of the present invention are methods that do not involve polymerization in interference fringe recording, 3) Latent image color development-colored body sensitized polymerization reaction, 6) Residual decoloring dye latent image-recording method using latent image sensitized polymerization reaction is also almost complete during the hologram exposure (first step). This is a method of performing refractive index modulation by polymerization in a lump in the entire surface exposure in the second step without being accompanied. Therefore, many multiplex recordings are possible in any of the methods 1) to 3), 5) and 6), and the exposure amount during multiplex recording remains constant throughout the multiplex recording. Since multiple recording can be performed while the refractive index modulation amount increases linearly with respect to the exposure amount, a wide dynamic range can be obtained. As described above, the recording methods 1) to 3), 5), and 6) of the present invention using the coloring method, the decoloring method, or the latent image amplification method are very advantageous in view of the above-mentioned multi-recording suitability.
This is preferable in terms of increasing the density (capacity), simplifying the recording system, improving the S / N ratio, and the like.

  As described above, the hologram recording material of the present invention is a completely new recording method that can solve both of the above-mentioned problems and can achieve both high sensitivity, good storage stability, dry processing, and multiple recording characteristics (high recording density). In particular, it is preferably used for an optical information recording medium (holographic optical memory).

Further, the hologram recording material of the present invention is disclosed in JP-T-2005-500581, JP-A-2005-501285, JP-A-3393064, JP-A-2003-85768, JP-A-2004-265472, JP-A-2004-265472. It can be used for a recording medium described in JP 2004-126040 A. Further, the hologram recording material of the present invention is disclosed in JP-A Nos. 2004-272268, 2004-177958, 2003-43904, 3451663, 2004-335044, and 2004. JP-A No. 361928, JP-A No. 2004-171611, JP-A No. 2003-228849, JP-A No. 2002-83431, JP-A No. 2002-123948, JP-A No. 2004-30734, and JP-A No. 2004-362750. In Japanese Patent No. 3430012, Japanese Patent Laid-Open No. 2003-178457, Japanese Patent Laid-Open No. 2003-178458, Japanese Patent Laid-Open No. 2003-178462, Japanese Patent Laid-Open No. 2003-178484, Japanese Patent Laid-Open No. 2003-151143, etc. Hologram using the recording / reproducing apparatus described It can be recorded and reproduced.

  In addition to the optical information recording medium, the hologram recording material of the present invention includes a three-dimensional display hologram, a holographic optical element (HOE, for example, a head-up display (HUD) mounted on an automobile, an optical disk pickup lens, a head Mounted displays, color filters for liquid crystals, reflective liquid crystal reflectors, lenses, diffraction gratings, interference filters, optical fiber couplers, facsimile light polarizers, architectural window glass), books, magazine covers, POP displays, etc. It can be preferably used for credit cards, banknotes, packaging and the like for security purposes for gifts and anti-counterfeiting.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited to the following example.
Reference example 1
[Hologram recording method by coloring method]
Under a red light, the sensitizing dye, electron donating compound, interference fringe recording component, additive, binder PMMA-EA (poly (methyl methacrylate-5% ethyl acrylate) copolymer, Mw 101000) shown in Table 1 were used. The composition for hologram recording material 101 to 110 was prepared by dissolving in 2 to 4 times the mass of methylene chloride (with acetone or acetonitrile if necessary). In addition, all% represents the mass% with respect to binder PMMA-EA.
The hologram recording material compositions 101 to 110 are applied to a glass substrate with a blade so that the thickness is about 80 μm (overcoated if necessary) to form a photosensitive layer, and then vacuum dried at room temperature for 1 day. The solvent was distilled off. Furthermore, hologram recording materials 101 to 110 were produced by covering the photosensitive layer with a TAC film.

The hologram recording materials in the hologram recording materials 101 to 110 were exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 400 seconds (irradiation energy ranges from 0.8 to 3200 mJ / cm ² ). And exposed. While exposing the hologram, a He—Ne laser beam of 632 nm was passed through the center of the exposure region at a black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time. In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material. In FIG. 2, reference numeral 10 is a YAG laser, 12 is a laser beam, 14 is a mirror, 20 is a beam splitter, 22 is a beam segment, 24 is a mirror, 26 is a spatial filter, 40 is a beam expander, and 30 is a hologram recording material. , 28 is a sample, 32 is a He—Ne laser beam, 34 is a He—Ne laser, 36 is a detector, and 38 is a rotary stage.
Table 2 shows the evaluation results of the maximum diffraction efficiency and the shrinkage rate in the hologram recording materials 101 to 110. The shrinkage rate was determined from the change in film thickness before and after recording. As a comparative example, JP-A-6
No.-43634 The radical polymerization photopolymer type hologram recording material of Example 1 was prepared.
The results are shown in Table 2.

  From Table 2, the comparative example described in Japanese Patent Application Laid-Open No. 6-43634 is high in diffraction efficiency but is a photopolymer system accompanied by radical polymerization, so it does not cause a large shrinkage exceeding 5%, especially for holographic memory applications. For example, the S / N ratio is extremely deteriorated. On the other hand, the hologram recording materials 101 to 110 of the present invention are hologram recording by refractive index modulation using a color reaction without using mass transfer and polymerization, and are completely different recording methods from known hologram recording materials. It has been found that a high diffraction efficiency and an extremely small shrinkage rate of 0.01% or less can be achieved at the same time, and is particularly suitable for holographic memory applications.

Furthermore, the hologram recording material of the present invention increases Δn (calculated based on Kugelnick's formula from refractive index modulation amount, diffraction efficiency and film thickness in interference fringes) almost linearly according to the exposure amount (mJ / cm ² ). However, this is advantageous for multiple recording.

  Actually, using the hologram recording material of the present invention, the multiplex hologram recording was performed 10 times in the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount giving the maximum diffraction efficiency. After that, it was confirmed that each object light can be reproduced by changing the angle of the reproduction light by 2 degrees and irradiating. That is, it can be seen that the hologram recording material of the present invention is capable of multiple recording with the same exposure amount and has multiple recording suitability. As described above, since the hologram recording material of the present invention can perform multiple multiplex recording, high-density (capacity) recording is possible.

  On the other hand, known photopolymer type hologram recording materials such as Japanese Patent Application Laid-Open No. 6-43634 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer proceeds and the movement of the monomer necessary for recording becomes slow. In this case, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.

In samples 101 to 110, the sensitizing dyes were S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, S-33, S. -34, S-43, S-45, S-46, S-50, S-58, S-67, S-73, S-74, S-77, S-80, S-91, S-94 , S-95, S-96, the same effect was obtained.
Further, in Samples 101 to 107, the acid generator of the interference fringe recording component is I-3, I-4, I-6, I-7, I-8, I-9, I-10, 4- (octylphenyl). ) Phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis (1- (4-diphenylsulfonium) phenyl sulfide ditriflate, dimethylphena Even if it is changed to silsulfonium perfluorobutane sulfonate, benzoin tosylate, I-22, or I-23, the acid coloring type dye precursor of the interference fringe recording component in samples 101 to 107 is L-1, L-3. , LC-1, LC-4, LC-9, LC-11, LC-12, LC-13 Effect was obtained.
Even if the base generator of the interference fringe recording component in the sample 108 is changed to PB-3, PB-4, PB-5, PB-6, PB-7, PB-8, PB-9, the sample At 108, the base color-forming dye precursor (dissociable dye non-dissociated substance) is converted to DD-1, DD-13, DD-15, DD-17, DD-22, DD-30, DD-31, DD-32, The same effect was obtained even when changed to DD-34, DD-35, DD-36, DD-37, DD-38.
Further, in the samples 109 and 110, the interference fringe recording components are E-5, E-9, E-10, E-11, E-12, E-13, E-14, E-15, E-16, E The same effect was obtained even when changed to -18, E-20, E-25, E-26, E-27, E-28, E-29, and E-30.
Further, even if the electron donor is changed to A-2, A-3, A-4, A-5, A-6, A-9, A-10, or A-11 in the samples 103 and 106 to 109, Similar effects were obtained.
In Samples 101 to 110, the binder was changed to polymethyl methacrylate (Mw 996000, 350,000, 120,000), poly (methyl methacrylate-butyl acrylate copolymer (Mw 75000), polyvinyl acetal (Mw 83000), polycarbonate, cellulose acetate butyrate, etc. However, the same effect was obtained.

Reference example 2
[Latent image color development-hologram recording method by color-sensitized polymerization reaction method]
Under a red light, sensitizing dye, electron donating compound, dye precursor group + polymerization initiator, polymerizable compound and binder shown in Table 3 were added in an amount of 2 to 5 times methylene chloride (acetone, acetonitrile or The holographic recording materials 201 to 204 were prepared by dissolving in a part of methanol). % Represents mass%.

  The hologram recording materials 201 to 204 are applied to a glass substrate with a blade so that the thickness is about 80 μm (overcoated if necessary), and after forming a photosensitive layer, the solvent is removed by vacuum drying at room temperature for 1 day. Distilled off. Further, hologram recording materials 201 to 204 were produced by covering the photosensitive layer with a TAC film.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 40 seconds (irradiation energy ranges from 0.8 to 320 mJ / cm ² ). (First step) A He-Ne laser beam of 632 nm is passed through the center of the exposure area at the black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) is measured in real time. (Diffraction efficiency η after the first step). In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.
Further, the entire surface was irradiated with light having a wavelength range of 370 to 410 nm (second step), and the diffraction efficiency was measured (diffraction efficiency η after the second step). Further, the amount of irradiation necessary to obtain the maximum diffraction efficiency only in the first step without using the second step is divided by the amount of irradiation necessary for the first step when the second step is used. Is the “amplification factor” and the above is summarized in Table 4.

From Table 4, in the hologram recording material of the present invention, the amount of light applied to the first step can be reduced to 1/5 to 1/7 as compared with the case where the second step is not used. Since the second step can be collectively exposed, the first step can be shortened, that is, increased by amplification of the refractive index modulation recording by causing polymerization in the second step using the color former of the first step as a latent image. It turns out that sensitivity improvement is possible. Needless to say, such a known material as disclosed in JP-A-6-43634 cannot achieve high sensitivity by such amplification.

Furthermore, the hologram recording material of the present invention is substantially linear in accordance with the exposure amount (mJ / cm ² ) after the first step and after the second step, Δn (refractive index modulation amount, diffraction efficiency and film in interference fringes). This is advantageous in the case of multiple recording.

  Actually, using the hologram recording material of the present invention, 10 times of multiple hologram recording was performed at the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount in the first step. After performing (first step), the entire surface was irradiated with light having a wavelength range of 370 to 410 nm to perform recording amplification by polymerization (second step). The angle of the reproduction light was changed by 2 degrees and irradiated. By doing so, it was confirmed that each object light can be reproduced. That is, it can be seen that the hologram recording material of the present invention can perform multiple recording with the same exposure amount and has multiple recording suitability. That is, the holographic recording material of the present invention can perform many multiplex recordings and can perform high density (capacity) recording.

On the other hand, known photopolymer hologram recording materials such as Japanese Patent Laid-Open No. 6-43634 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of monomers necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.
On the other hand, the hologram recording method of the present invention uses a color development reaction instead of polymerization for the hologram recording (first step) and uses it as a latent image. Are better.

In samples 201 to 204, the sensitizing dyes are S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, S-33, S. -34, S-43, S-45, S-46, S-50, S-58, S-67, S-71, S-73, S-74, S-75, S-77, S-80 , S-81, S-88, S-91, S-94, S-95, S-96, the same effect was obtained.
Further, in the samples 201 and 202, the acid generator (also serving as cation or radical polymerization initiator) of the interference fringe recording component is I-3, I-4, I-6, I-7, I-8, I-9, I-10,4- (octylphenyl) phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis (1- (4-diphenyl) Even if it is changed to sulfonium) phenyl sulfide ditriflate or dimethylphenacylsulfonium perfluorobutane sulfonate, the acid coloring type dye precursor of the interference fringe recording component in samples 201 and 202 is L-1, L-3, LC-1. , LC-4, LC-9, LC-11, LC-12, LC-13 Obtained.
In Sample 203, the interference fringe recording component and polymerization initiator base generator (also anion polymerization initiator) were used as PB-3, PB-4, PB-5, PB-6, PB-7, and PB-8. , PB-9, the base color-forming dye precursor (dissociable dye non-dissociated substance) is changed to DD-1, DD-13, DD-15, DD-17, DD-22, DD in Sample 203. The same effect was obtained even if it was changed to -30, DD-31, DD-32, DD-34, DD-35, DD-36, DD-37, DD-38.
In Sample 204, the dye precursors are E-3, E-5, E-9, E-10, E-11, E-12, E-13, E-14, E-15, E-16, Even if it changes to E-18, E-20, E-25, E-26, E-27, E-28, E-29, E-30,
Even when the radical polymerization initiator was changed to I-1, I-11 to I-20 or the like in sample 204, the same effect was obtained.
In Samples 201 to 204, the electron donors are A-2, A-3, A-4, A-5, A-6.
, A-9, A-10, A-11, the same effect was obtained.
In the above case, the optimal wavelength was used for the light for performing the entire surface exposure in each system.

Reference example 3
[Hologram recording method using decoloring method (sensitizing dye + decolorizable dye)]
Under red light, sensitizing dye, electron donating compound, decoloring agent precursor, decoloring dye, binder PMMA-EA (poly (methyl methacrylate-5% ethyl acrylate) copolymer shown in Table 5 Mw 101000) was dissolved in 2 to 4 times the weight of methylene chloride (with acetone or acetonitrile if necessary) to prepare compositions 301 to 307 for hologram recording material. In addition, all% represents the mass% with respect to binder PMMA-EA.

  This composition for hologram recording material 301 to 307 is applied to a glass substrate with a blade so that the thickness is about 80 μm (overcoat if necessary) to form a photosensitive layer, followed by vacuum drying at room temperature for 1 day. The solvent was distilled off. Further, hologram recording materials 301 to 307 were produced by covering the photosensitive layer with a TAC film.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 400 seconds (irradiation energy ranges from 0.8 to 3200 mJ / cm ² ). And exposed. While exposing the hologram, a He—Ne laser beam of 632 nm was passed through the center of the exposure area at a black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time. In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.

  As a comparative example, a photopolymer hologram recording material of Example 1 of JP-A-6-43634 was prepared.

  From Table 6, the comparative example described in Japanese Patent Laid-Open No. 6-43634 is a photopolymer system with radical polymerization, although it has a high diffraction efficiency, so it has a large shrinkage exceeding 5%, especially as a holographic memory application. Is not suitable because the S / N ratio is extremely deteriorated. In contrast, the hologram recording materials 301 to 307 of the present invention are completely different from known hologram recording materials that perform hologram recording by refractive index modulation using a decoloring reaction without using mass transfer and polymerization. It can be seen that a high diffraction efficiency and an extremely small shrinkage rate of 0.01% or less can be achieved at the same time, and it is particularly suitable for holographic memory applications.

Furthermore, the hologram recording material of the present invention increases Δn (calculated based on Kugelnick's formula from refractive index modulation amount, diffraction efficiency and film thickness in interference fringes) almost linearly according to the exposure amount (mJ / cm ² ). However, this is advantageous for multiple recording.

Actually, using the hologram recording material of the present invention, 10 times of multiple hologram recordings were performed at the same place by changing the angle of the reference light by 2 degrees with a light amount of 1/10 of the exposure amount giving the maximum diffraction efficiency. After that, it was confirmed that each object light can be reproduced by changing the angle of the reproduction light by 2 degrees and irradiating. That is, it can be seen that the hologram recording material of the present invention is capable of multiple recording with the same exposure amount and has multiple recording suitability. As described above, since the hologram recording material of the present invention can perform multiple multiplex recording, high-density (capacity) recording is possible.

  On the other hand, known photopolymer hologram recording materials such as Japanese Patent Laid-Open No. 6-43634 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of monomers necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.

Reference example 4
[Remaining decolorizable dye latent image-hologram recording method by latent image sensitization polymerization method]
Under red light, the sensitizing dye, electron donating compound, decoloring dye, decoloring agent precursor, polymerization initiator, polymerizable compound and binder shown in Table 7 were added in an amount of 2 to 5 times the amount of methylene chloride ( A part of acetone, acetonitrile, or methanol was used if necessary) to prepare hologram recording materials 401 to 404. % Represents mass%.

  The hologram recording materials 401 to 404 are applied to a glass substrate with a blade so as to have a thickness of about 80 μm (overcoated if necessary), and after forming a photosensitive layer, the solvent is removed by vacuum drying at room temperature for 1 day. Distilled off. Further, hologram recording materials 401 to 404 were produced by covering the photosensitive layer with a TAC film.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 40 seconds (irradiation energy ranges from 0.8 to 320 mJ / cm ² ). (First step) A He—Ne laser beam of 632 nm was passed through the center of the exposure region at the black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time ( Diffraction efficiency after first step (η). In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.
Further, the entire surface was irradiated with light having a wavelength range of 370 to 410 nm (second step), and the diffraction efficiency was measured (diffraction efficiency η after the second step). Further, the amount of irradiation necessary to obtain the maximum diffraction efficiency only in the first step without using the second step is divided by the amount of irradiation necessary for the first step when the second step is used. Is the “amplification factor” and the above is summarized in Table 8.

  From Table 8, in the hologram recording material of the present invention, the amount of light applied to the first step can be reduced to 1/5 to 1/7 as compared with the case where the second step is not used. Since the second process is capable of batch exposure, the first process is shortened by amplification of refractive index modulation recording by causing polymerization using the remaining decolorizable dye in the first process as a latent image in the second process. That is, it can be seen that high sensitivity can be achieved. Naturally, it is impossible to increase the sensitivity by such amplification with a known material as described in JP-A-6-43634.

Furthermore, the hologram recording material of the present invention is substantially linear in accordance with the exposure amount (mJ / cm ² ) after the first step and after the second step, Δn (refractive index modulation amount, diffraction efficiency and film in interference fringes). This is advantageous in the case of multiple recording.

  Actually, using the hologram recording material of the present invention, 10 times of multiple hologram recording was performed at the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount in the first step. After performing (first step), the entire surface was irradiated with light having a wavelength range of 370 to 410 nm to perform recording amplification by polymerization (second step). The angle of the reproduction light was changed by 2 degrees and irradiated. By doing so, it was confirmed that each object light can be reproduced. That is, it can be seen that the hologram recording material of the present invention can perform multiple recording with the same exposure amount and has multiple recording suitability. That is, the holographic recording material of the present invention can perform many multiplex recordings and can perform high density (capacity) recording.

On the other hand, known photopolymer hologram recording materials such as Japanese Patent Laid-Open No. 6-43634 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of monomers necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.
On the other hand, the hologram recording method of the present invention uses a decoloring reaction instead of polymerization for hologram recording (first step) and uses it as a latent image. Is excellent.

In Samples 301 to 307 and 401 to 404, sensitizing dyes are S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, and S. -33, S-34, S-43, S-45, S-46, S-50, S-58, S-67, S-71, S-73, S-74, S-77, S-80 , S-81, S-88, S-91, S-94, S-95, S-96, the same effect was obtained.
Further, in samples 301 to 306, 401, and 402, decolorizer precursors (acid generators, sometimes combined acids or radical polymerization initiators) were changed to I-3, I-4, I-6, I-7, I. -8, I-9, I-10,4- (octylphenyl) phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis Even if it is changed to (1- (4-diphenylsulfonium) phenyl sulfide ditriflate, dimethylphenacylsulfonium perfluorobutanesulfonate, benzoin tosylate, I-22, I-23, samples 301 to 306, 401, 402 Acid decolorizable dyes are G-14, G-17, G-21, G-22, and G-26. Similar effects G-27 was obtained.
Further, in Samples 307 and 403, the decolorizer precursor (base generator, possibly also an anionic polymerization initiator) was changed to PB-3, PB-4, PB-5, PB-6, PB-7, PB-8. , PB-9, but the base decoloring dyes in Samples 307 and 403 are G-29, G-32, G-38, G-40, G-42, G-43, G-44, Even if it changed to G-45, the same effect was acquired. Further, even if the radical polymerization initiator is changed to I-1, I-11 to I-20 or the like in the sample 404, the decolorizable dyes in the sample 404 are G-48, G-49, G-51, Even if it changed to G-52, the same effect was acquired.
In Samples 301 to 303, 306, 307, and 402 to 404, the electron donors are A-2, A-3, A-4, A-5, A-6, A-9, A-10, A- The same effect was obtained even when changed to 11.
Further, in samples 301 to 307, the binder is changed to polymethyl methacrylate (Mw 996000, 350,000, 120,000), poly (methyl methacrylate-butyl methacrylate) copolymer (Mw 75000), polyvinyl acetate (Mw 83000), polycarbonate, cellulose acetate butyrate and the like. Even if it was changed, the same effect was obtained.
In the above case, the optimal wavelength was used for the light for performing the entire surface exposure in each system.

Example 1
FIG. 3 is a diagram showing the configuration of the optical information recording medium in the first embodiment. Optical information recording medium 1
In 01, servo pits are formed on a polycarbonate or glass substrate 1, and a reflective layer 2 is provided thereon by coating with aluminum, gold, platinum or the like. Unlike FIG. 1, servo pits are formed on the entire surface of the substrate in FIG. 3, but they may be formed periodically as shown in FIG. The maximum height of the servo pit is 1750 mm, which is sufficiently smaller than the heat of other layers including the substrate.

  Further, a red light transmission filter layer 6 is provided on the substrate 1 with the reflective layer 2, and the optical recording medium 101 is sandwiched between the hologram recording material as the hologram recording layer 4 by the upper substrate 5 (polycarbonate, glass, etc.). Is configured.

   In FIG. 3, the red light transmission filter layer 6 transmits only red light and does not transmit light of other colors. Therefore, since the information light and the recording / reproducing reference light are green or blue light, the light does not pass through the filter layer 6 and does not reach the reflection layer 2 and becomes return light, which is emitted from the incident / exit surface A. Become. The red light transmission filter layer 6 is, for example, a cholesteric liquid crystal layer, and CM-33 manufactured by Chisso Corporation or the like can be used. When a cholesteric liquid crystal layer is used, a quarter-wave plate in the optical information recording medium 101 and between the filter layer (cholesteric liquid crystal layer) 6 and the incident / exit surface A is used. Or a quarter-wave plate as an optical configuration is arranged between the dichroic mirror 15 and the optical information recording medium 101, which will be described later, even if not in the optical information recording medium 101. Good. This quarter-wave plate is shifted by a quarter wavelength only with respect to green light, and when green light is incident, it becomes circularly polarized light, but light of other colors (for example, red) Is made to be elliptically polarized light when incident.

  The optical information recording medium 101 in the first embodiment may be disk-shaped or card-shaped. In the case of a card shape, there is no need for servo pits. In this optical information recording medium 101, the substrate 1 has a thickness of 0.6 mm, the red light transmission filter 6 has a thickness of 2 to 3 μm, the hologram recording layer 4 has a thickness of 0.6 mm, and the substrate 5 has a thickness of 0.6 mm. It is almost 1.8 mm.

  Next, the optical operation around the optical information recording medium 101 will be described with reference to FIG. First, light (red light) emitted from the servo laser is 100% reflected by the dichroic mirror 15 and passes through the objective lens 17. Servo light is irradiated onto the optical information recording medium 101 by the objective lens 17 so as to be focused on the reflective layer 2. That is, the dichroic mirror 15 transmits light having a wavelength of green or blue and reflects light having a wavelength of red almost 100%. The servo light incident from the light incident / exit surface A of the optical information recording medium 101 passes through the substrate 5, the hologram recording layer 4 and the red transmission filter layer 6, is reflected by the reflection layer 2, and is again filtered by the filter layer 6 and hologram. The light passes through the recording layer 4 and the substrate 5 and is emitted from the incident / exit surface A. The returned return light passes through the objective lens 17, is reflected 100% by the dichroic mirror 15, and servo information is detected by a servo information detector (not shown). The detected servo information is used for focus servo, tracking servo, slide servo, and the like. Since the hologram recording material constituting the hologram recording layer 4 is not sensitive to red light, even if the servo light passes through the hologram recording layer 4 or the servo light is irregularly reflected by the reflection layer 2. The hologram recording layer 4 is not affected. Further, since the return light of the servo light reflected by the reflection layer 2 is reflected almost 100% by the dichroic mirror 15, the servo light is not detected by the CMOS sensor or the CCD 19 for detecting the reproduced image. And there is no noise with respect to the reproduction light.

The information light and the recording reference light generated from the recording / reproducing laser pass through the dichroic mirror 15, and the information light and the recording reference light generate an interference pattern in the hologram recording layer 4 by the objective lens 11. In this manner, the optical information recording medium 101 is irradiated. The information light and the recording reference light enter from the incident / exit surface A and interfere with each other at the hologram recording layer 4 to generate an interference pattern there. Thereafter, the information light and the recording reference light pass through the hologram recording layer 4 and enter the red light transmission filter layer 6, but are reflected to the bottom surface of the layer to become return light. That is, the information light and the recording reference light do not reach the reflective layer 2. This is because the red light transmission filter layer 6 has a property of transmitting only red light.

Example 2
FIG. 4 is a diagram showing the configuration of the optical information recording medium in the second embodiment. In the optical information recording medium 102 according to the second embodiment, servo pits are formed on a polycarbonate or glass substrate 1, and a reflective layer 2 is provided thereon by coating with aluminum, gold, platinum or the like. The servo pit has a maximum height of 1750 mm as in the first embodiment.

  The difference in structure between the second embodiment and the first embodiment is that the optical information recording medium 102 according to the second embodiment has the gap layer 8 and the dichroic mirror layer 9 instead of the filter layer 6 of the optical information recording medium 101. And a quarter-wave plate layer 7 is provided between the dichroic mirror layer 9 and the hologram recording layer 4.

  The gap layer 8 is formed by applying a material such as UV resin on the reflective layer 2 of the substrate 1 by spin coating or the like. The gap layer 8 protects the reflective layer 2 and is effective for adjusting the size of the hologram generated in the hologram recording layer 4. That is, it is necessary to form an interference area between the recording reference beam and the information beam in the hologram recording layer 4 to a certain size. Therefore, it is effective to provide a gap between the hologram recording layer 4 and the servo pit.

  The dichroic mirror layer 9 is formed by coating a dielectric multilayer film (sputtering) on the gap layer 8 with a wavelength separation filter. The dichroic mirror according to the second embodiment has a property of reflecting green light and transmitting other light (for example, red).

  The quarter-wave plate layer 7 is formed by spin-coating a material for generating a phase difference, for example, azobenzene on the dichroic mirror layer 9. A film formed of azobenzene has photo anisotropy and has a property of arranging molecules in a vertical direction with respect to the irradiated polarized light. In addition, the quarter-wave plate layer 7 can be generated by using a so-called rubbing process. When a linearly polarized light such as P-polarized light or S-polarized light enters the quarter-wave plate, the angle formed by the direction of the linearly-polarized light with respect to the optical axis of the crystal in the quarter-wave plate is 45 degrees. In some cases, the passing light is changed from linearly polarized light to circularly polarized light, and conversely, if circularly polarized light is incident, it has the property of being converted to linearly polarized light. In the present embodiment, the quarter-wave plate layer 7 has a function of removing a ghost caused by a reflection type hologram (Horizontal Fringe), and this layer is not provided when the influence of the ghost can be ignored. It doesn't matter.

  In the optical information recording medium 102, the substrate 1 is 0.6 mm, the gap layer 8 is 2 to 3 μm, the dichroic mirror layer 9 is 1 μm or less, the quarter-wave plate layer 7 is 20 μm or less, and the hologram recording layer 4 is 0. .6 mm, the substrate 5 is 0.6 mm thick, and the total is approximately 1.8 mm.

When recording or reproducing information, the optical information recording medium 102 having such a structure is irradiated with red servo light, green information light, and recording / reproducing reference light. The servo light enters from the incident / exit surface A, passes through the hologram recording layer 4, the quarter-wave plate layer 7, the dichroic mirror layer 9, and the gap layer 8, and is reflected by the reflective layer 2 to return light. Become. The return light again passes through the gap layer 8, the dichroic mirror layer 9, the quarter-wave plate layer 7, the hologram recording layer 4, and the substrate 5 in this order, and exits from the incident / exit surface A. The emitted return light is used for focus servo, tracking servo, and the like. Since the hologram recording material constituting the hologram recording layer 4 is not sensitive to red light, even if the servo light passes through the hologram recording layer 4 or the servo light is irregularly reflected by the reflection layer 2. The hologram recording layer 4 is not affected. Green information light or the like enters from the incident / exit surface A, passes through the hologram recording layer 4, the quarter-wave plate layer 7, is reflected by the dichroic mirror layer 9, and becomes return light. The return light again passes through the quarter-wave plate layer 7, the hologram recording layer 4, and the substrate 5 in this order, and exits from the incident / exit surface A. Also during reproduction, not only the reproduction reference light but also the reproduction light generated by irradiating the hologram recording layer 4 with the reproduction reference light is emitted from the incident / exit surface A without reaching the reflection layer 2. Note that the reproduction light is reflected by the dichroic mirror layer 9 depending on the recording method, that is, whether the reflection hologram or the transmission hologram is recorded.
The optical operation of the objective lens 17, dichroic mirror 15, CMOS sensor or CCD 19 as a detector in the vicinity of the optical information recording medium 102 (FIG. 7) is the same as that of the first embodiment (FIG. 7), and the description thereof is omitted. .
Example 3
FIG. 5 is a diagram illustrating a configuration of an optical information recording medium according to the third embodiment. In the optical information recording medium 103 according to the third embodiment, a cholesteric liquid crystal layer 11 is provided instead of the dichroic mirror layer 9 in the second embodiment. Other configurations are the same as those of the second embodiment.

  The cholesteric liquid crystal layer 11 also has a thickness of 1 to 2 μm, and the entire optical information recording medium is approximately 1.8 mm as in the other embodiments.

  The cholesteric liquid crystal layer 11 is formed by forming a gap layer (smooth layer) 8 and then applying, for example, a cholesteric liquid crystal CM-33 (manufactured by Chisso Corporation), which is a chiral dopant, and performing spin coating. A cholesteric liquid crystal reflects light when circularly polarized light in a predetermined direction is incident on the cholesteric liquid crystal, and when other light such as circularly polarized light in the reverse direction, linearly polarized light, or elliptically polarized light is incident on the cholesteric liquid crystal. It has the property of transmitting light.

  In the third embodiment, the quarter-wave plate layer 7 has a property of shifting a quarter wavelength only with respect to green light. That is, in the quarter-wave plate layer 7, when linearly polarized green light (information light and reference light) is incident, it is changed to circularly polarized green light, and linearly polarized red light (servo light). Is changed to elliptically polarized red light. Accordingly, the green information light and the reference light that are changed from linearly polarized light to circularly polarized light by the quarter-wave plate layer 7 are reflected by the cholesteric liquid crystal layer 11 and do not reach the reflective layer 2. Red servo light changed from linearly polarized light to elliptically polarized light by the quarter-wave plate layer 7 passes through the cholesteric liquid crystal layer 11 and reaches the reflective layer 2, and the return light is a forensic servo or tracking servo. Used for etc.

Example 4
FIG. 6 is a diagram showing the configuration of the optical information recording medium in the fourth embodiment. In the optical information recording medium 104 according to the fourth embodiment, the reflective layer 2 in the third embodiment is not a simple metal reflective film such as Al, but a recording medium that can be additionally written or rewritten, for example, a phase change film. Other configurations are the same as those of the third embodiment. Accordingly, the operation of the cholesteric liquid crystal layer 11 is the same as that of the third embodiment, and the description thereof is omitted.

  In the optical information recording medium 100 having the configuration shown in FIG. 1, information light and reference light (green light) having high light intensity are also collected on the reflecting surface when recording a hologram. However, there is a problem in securing reliability even if it is intended to have a write-once function using the same red light. In addition, the reflectivity of the additionally writable or rewritable film is not so high, and there is a problem that the reproduction efficiency of the hologram is lowered.

  However, since the reflectance of green light can be set independently by the cholesteric liquid crystal layer 10 which is a wavelength separation layer in the method according to the present embodiment, the reflection layer 13 for red light for servo may have a low reflectance. There are advantages.

(Effect of each embodiment)
According to each embodiment, since light of two types of wavelengths is efficiently separated, light of two types of wavelengths (red light and green light) can be used for different purposes without being affected by each. it can.

  In addition, a polarization direction changing layer that polarizes the light changing direction, for example, a layer made of a quarter-wave plate, is provided between the recording layer and the filter layer. As a result, it is possible to prevent the polarization direction of light from being changed and the generation of a ghost image by a reflection hologram.

  Furthermore, according to each embodiment, the information light and the reference light used during recording or reproduction, and further the reproduction light do not reach the reflective layer 2 or 13, so that diffused light due to irregular reflection on the reflective surface is generated. Can be prevented. Therefore, the noise generated by the diffused light is not superimposed on the reproduced image and detected on the CMOS sensor or the CCD 19, but the reproduced image can be detected at least to the extent that error correction is possible. The noise component due to diffused light becomes a serious problem as the multiplicity of holograms increases. That is, as the multiplicity increases, for example, when it is 1000 or more, the diffraction efficiency from one hologram becomes extremely small, and detection of a reproduced image becomes very difficult if there is diffusion noise. According to the present invention, such a difficulty can be eliminated, which is effective. Also, with this configuration, unlike the conventional optical information recording medium of FIG. 1, the servo pit is not limited to the sample servo but can take any form of pre-pit structure. Furthermore, the interval between the pits can be arranged without depending on the hologram size.

  In Examples 2 to 4, most of the reproduced light generated by the polarization beam splitter (not shown) used in the recording / reproducing optical system is obtained by orthogonalizing the incident light of the quarter-wave plate layer 7 and the outgoing light. Since it can be detected, light utilization efficiency is high and optically excellent. This combination is also very effective in removing unnecessary stray light such as surface reflection of an optical element generated on the laser light source side (not shown) from the quarter wavelength layer 7.

  Further, since the arrangement of the servo pits and the hologram recording are optically separated, no matter what pit format is adopted, the recording density is not lowered. Therefore, a sufficient frequency band can be given to the servo control signal, and the servo accuracy can be improved to be equal to or higher than that of the conventional optical disc.

  Further, according to the present invention, the reflectance of the reflective film for servo can be freely selected, and the material of the reflective film can be freely selected. Therefore, as in the fourth embodiment, a recording medium that can be additionally recorded or rewritten on the reflective layer 13, for example, a DVD (digital video disk) is used. It is also possible to add and / or rewrite directory information and the like such as how the replacement process is performed due to an error in the part without affecting the hologram.

  Since the filter layer which is the wavelength separation film can be formed relatively thin on the order of microns, the optical lens of the objective lens caused by the deviation of the reflection surface by the filter layer 6, 9 or 11 and the reflection surface by the reflection layer 2 or 13 can be used. The influence of aberration is negligible.

Furthermore, because a specific optical refractive index modulation component is used as the recording layer, both high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, and multiple recording characteristics (high recording density) must be achieved. It is possible to provide an optical information recording medium capable of

  In the above embodiment, red light is used as servo light and green light is used as recording / reproducing light. However, the present invention is not limited to this, and combinations of light of other wavelengths are possible depending on the properties of the medium.

It is a figure which shows the structure of the conventional optical information recording medium. It is the schematic explaining the two-beam optical system for hologram exposure. It is a figure for demonstrating the optical information recording medium of Example 1 by this invention. It is a figure for demonstrating the optical information recording medium of Example 2 by this invention. It is a figure for demonstrating the optical information recording medium of Example 3 by this invention. It is a figure for demonstrating the optical information recording medium of Example 4 by this invention. It is a figure which shows the optical system of the optical information recording medium periphery by this invention.

Explanation of symbols

1 Lower substrate (with servo pit)
2 Reflective layer 4 Hologram recording layer 5 Upper substrate 6 Filter layer 7 Quarter wave plate layer 8 Gap layer 9 Dichroic mirror layer 10 YAG laser 11 Cholesteric liquid crystal layer 12 Laser beam 13 Phase change reflective layer 14 Mirror 20 Beam splitter 22 Beam Segment 24 Mirror 26 Spatial filter 28 Sample 30 Hologram recording material 32 He-Ne laser beam 34 He-Ne laser 36 Detector 38 Rotating stage 40 Beam expander

Claims (11)

An optical information recording medium for recording information using holography,
A transparent substrate;
A recording layer on which information is recorded by an interference pattern;
A filter layer that is provided between the transparent substrate and the recording layer and transmits light of a first wavelength and reflects light of a second wavelength;
The recording layer has 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction, 3) latent image color development-colored body sensitized polymerization reaction, 4) orientation change of compound having intrinsic birefringence. 5) A photorefractive index modulation component that records interference fringes as refractive index modulation by any one of the method of 5) dye decolorization reaction and 6) residual decolorization dye latent image-latent image sensitization polymerization reaction. Optical information recording medium.   The optical information recording medium according to claim 1, wherein the transparent substrate has a servo pit pattern.   The optical information recording medium according to claim 2, wherein the transparent substrate has a reflective surface formed on the servo pit pattern.   The optical information recording medium according to claim 1, wherein a polarization direction changing layer for polarizing a light changing direction is provided between the recording layer and the filter layer.   5. The optical information recording medium according to claim 4, wherein the polarization direction changing layer is a layer made of a quarter-wave plate.   The optical information recording medium according to claim 1, wherein the filter layer is a layer made of a dichroic mirror.   6. The optical information recording medium according to claim 4, wherein the filter layer is a layer made of cholesteric liquid crystal.   The polarization direction changing layer changes the light of the second wavelength to circularly polarized light in a predetermined direction, and changes the light of the first wavelength to light of polarized light other than the circularly polarized light in the predetermined direction. 8. The optical information recording medium according to claim 7, wherein:   4. The optical information recording medium according to claim 3, wherein the reflection surface is a metal reflection film.   4. The optical information recording medium according to claim 3, wherein the reflection surface is a medium surface that reflects light and is additionally recordable or erasable.   4. The optical information recording medium according to claim 3, wherein a gap layer for smoothing the surface of the substrate is provided between the filter layer and the reflection surface.

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