JPH07302425A - Non-destructive read method - Google Patents

Abstract

PURPOSE:To non-destructively detect a state change before and after the photochromic reaction by photoirradiation by detecting the degree of polarization of a compd. of which the degree of polarization changes before and after the photoreaction of the photochromic compd. CONSTITUTION:Recording (writing) in an optical recording medium is executed by casting light which is focused to about 1 to 10mum and has the wavelength capable of inducing photoisomerization, more preferably a laser beam, to the recording layer disposed on both surface or one surface of a substrate. A color change is induced by the photoisomerization in the parts irradiated with the laser beam, etc. The reproduction of the recorded information is executed by reading the difference in the degrees of polarization between the parts where the color change is induced and the parts where the color change is not induced, by which the reproduction of the information as digital information or analog information is made possible. In such a case, the light of the long wavelength is usable and the non-destructive reading out is thereby executed without progression of the photoreaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nondestructive reading method, and more particularly to a recording / reproducing method capable of reading a large number of times by reading information of information by an optical recording material substantially nondestructively.

[0002]

It has been difficult for non-destructive detection of state changes before and after a photochromic reaction by light irradiation in a conventional photosensitive material or optical recording medium using a fulgide compound. That is, when the state change is repeatedly detected, the information is destroyed and it is difficult to use these recording media.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a reading method capable of non-contact and non-destructively detecting the state before and after the reaction. Yes, it was achieved by detecting the optical rotation of the compound whose optical rotation changes before and after the photoreaction of the photochromic compound.

The destructive read-out method of the present invention is a non-destructive read-out method for a photosensitive material or an optical recording medium using a photochromic compound, wherein the photochromic compound has optical rotation between a reaction product before and after a photoreaction. It is characterized in that a compound having a difference in is used and information is reproduced by using the difference in optical rotation. Hereinafter, the present invention will be described in detail.

In the nondestructive reading method of the present invention, for example, recording (writing) on an optical recording medium is performed at a wavelength capable of causing photoisomerization focused to about 1 to 10 μm in a recording layer provided on both sides or one side of a substrate. Light, preferably laser light. A portion irradiated with laser light or the like undergoes color change due to photoisomerization. The recorded information can be reproduced as digital information or analog information by reading the difference in optical rotation between a portion where color change has occurred and a portion where color change has not occurred. In the conventional method, the color change itself before and after the photoisomerization reaction is read out, and since the photoreaction proceeds in proportion to the absorbed light amount, there is a problem that the information disappears even if a weak reproducing light is used and read out many times. Was there. On the other hand, in the present invention, as the reproduction light, light having a long wavelength which the present compound does not absorb can be used, whereby the photoreaction does not proceed, and nondestructive readout is possible.

Information is erased by visible light (eg, 490 nm)
It can be performed by irradiating. The photochromic compound used in the present readout method can be used as long as it has a detectable optical rotation difference before and after the photoreaction, and a fugenolide compound described later or indolylfulgide used in Example 2, for example, can be used. It is preferably exemplified.

The light source used for the optical recording medium of the present invention includes a mercury lamp, a xenon lamp, a laser beam (N ₂ , He-Cd, argon ion, He-Ne,
Ruby, semiconductor, dye laser) and the like. The fulgenolide compound, which is mentioned as an example of the preferable photochromic compound used in the reading method of the present invention represented by the above general formula [I], is obtained from, for example, a fulgide compound and a 2,2′-binaphthol compound. That is, a fulgide compound represented by the following general formula [IV] and a (R) -2,2′-binaphthol compound represented by the following general formula [V] are hydrogenated in an organic solvent under cooling at 10 ° C. or lower. The reaction is carried out in the presence of a reducing agent such as sodium chloride to obtain the half ester represented by the general formula [VI]. By condensing the half ester in an organic solvent in the presence of a condensing agent such as trifluoroacetic anhydride or acetic anhydride, a compound represented by the above general formula [I] can be obtained.

[0008]

[Chemical 1]

In the above general formulas [I], [IV] to [VI],
And X is -O-, -S- or -N-R⁷-Indicates
To -NR⁷− Is suitable for nondestructive read
It R¹, R², R³, R^Four, R^Five, R⁶, R⁷, R⁸
And R⁹Is hydrogen atom; fluorine atom, chlorine atom, bromine
Halogen atom such as atom; methyl group, ethyl group, propyl
Group, alkyl group such as butyl group; phenyl group, naphthyl group
Aryl groups such as; benzyl groups, naphthylmethyl groups, etc.
Ralalkyl group; alkoxy such as methoxy group and ethoxy group
Group; methoxycarbonyl group, ethoxycarbonyl group, etc.
Alkoxycarbonyl group; carboxyl group; nitro group;
Amino group: Monoamino group such as methylamino group and ethylamino group
Rukylamino group; dimethylamino group, diethylamino group
Or a vinyl group. the above
Aryl and vinyl groups include halogen atoms, alkyl
It may have a substituent such as a group, and the above aralkyl group
Similarly, the aromatic ring of is a substituent such as a halogen atom or an alkyl group.
May have. Also, R³And R^FourCombined with
Cyclize to form an aromatic ring such as a benzene ring or naphthalene ring.
And the aromatic ring is¹~ R⁹Groups like
May have. Also, R^FiveAnd R⁶Are combined and
R, forming propylene, etc.^FiveAnd R⁶The carbon to which
It may form a carbocycle or a heterocycle with the atom. R
¹, R^FiveAnd R ⁶Is preferably a substituent other than a hydrogen atom
In particular, an alkyl group, more preferably a methyl group is preferable.

Among the fulgenolide compounds represented by the general formula [I], the novel fulgenolide compounds represented by the following general formula [IIa] or [IIb] are particularly suitable for nondestructive readout. The compounds represented by the general formulas [IIa] and [IIb] are diastereomers, and in these formulas, R ^{10 to} R ¹⁷ represent the same atom or group as those of R ^{1 to} R ⁹ . Among them, R ¹⁰ , R ¹⁴ and R ¹⁵ are preferably other than hydrogen atom for repeated reading,
Particularly, an alkyl group and more preferably a methyl group are preferable.

[0011]

[Chemical 2]

(Wherein R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ ,
R ¹⁵ , R ¹⁶ and R ¹⁷ are a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, an aralkyl group which may have a substituent on the aromatic ring, an alkoxy group, an alkoxycarbonyl. A group, a carboxyl group, a nitro group, an amino group, a mono- or dialkylamino group or a vinyl group which may have a substituent is shown. )

Among the compounds represented by the general formulas [IIa] and [IIb], the fulgenolide compound represented by the following general formula [IIIa] or [IIIb] is excellent in terms of repeated durability of nondestructive readout. There is. The compounds represented by the general formulas [IIIa] and [IIIb] are diastereomers.

[0014]

[Chemical 3]

In the general formulas [IIIa] and [IIIb], R ¹⁸ and R ¹⁹ are each independently methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, t- Butyl group, n-pentyl group, n-hexyl group,
Represents a linear or branched alkyl group such as n-heptyl group, n-octyl group, and n-nonyl group, and particularly has 1 to 6 carbon atoms.
Alkyl groups of are suitable.

The fulgenolide compound represented by the general formula [IIa] or [IIb] is represented by the formula [IV] in the above reaction formula.
Instead of the compound of formula (VII), a compound of formula (VII) below is used to react in the same manner as the compound of formula (VIII), and half-esters of formula (IX) below can be used to synthesize the compound. .

[0017]

[Chemical 4]

In the general formulas [VI] to [VIII],
R ¹⁰ to R ¹⁷ are as defined as in the general formula [IIa] [IIb]. The compound represented by the above general formula [I] is
Photochromism, which reversibly produces two isomers by the action of light, is shown. Specifically, for example, the general formula [III
The compounds represented by the formulas [a] and [IIIb] are represented by the equilibrium formulas below, and are colorless in the states of [IIIa] and [IIIb], but they are represented by the general formula [X] by irradiation with ultraviolet rays. Then, the color changes to the original state by irradiation with visible light and becomes colorless, and this state change is repeated.

[0019]

[Chemical 5]

Next, the photosensitive material used in the present invention will be described. The light-sensitive material used in the present invention is a light-sensitive layer containing a photochromic compound having a difference in optical rotation, such as the above-mentioned fulgenolide compound, dissolved or dispersed in a resin, or a microcapsulated product dispersed in a resin. Can be manufactured according to a known method.

The substrate may be either transparent or opaque, but when the substrate is provided on both sides of the photosensitive layer, it is necessary that at least one side is transparent in order to be exposed to light.

As the material of the substrate, a support such as glass, plastic, paper, plate-shaped or foil-shaped metal and a composite of these is used, but glass or plastic is preferable from various points. Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin,
Examples thereof include vinyl chloride resin, polyethylene resin, polypropylene resin, polycarbonate resin, polysulfone resin and the like.

As the resin for dissolving or dispersing the photochromic compound, polyester resin, polystyrene resin, polyvinyl butyral resin, polyvinylidene chloride,
Polyvinyl chloride, polymethyl methacrylate, polyvinyl acetate, cellulose acetate, epoxy resin, phenolic resin, polyacetal and the like, as the solvent to be used, carbon tetrachloride, benzene, cyclohexane, methyl ethyl ketone, methyl isobutyl ketone, tetrachloroethane, Toluene, ethanol, ethyl cellosolve and the like can be mentioned.

When the photochromic compound is dissolved or dispersed in the above resin, its concentration is 3 to 5 with respect to the resin.
It is suitable to be 0% by weight, preferably 5 to 20% by weight.

On the other hand, as a microencapsulation method,
A commonly known method, for example, the method described in the document [Tamotsu Kondo “Latest microencapsulation technology” (Comprehensive Technology Center)] can be mentioned. That is, chemical methods such as interfacial polymerization method and in-situ polymerization method, phase separation method (simple coacervation method, complex coacervation method), physicochemical methods such as interfacial precipitation method, spray drying method, airborne method. A physical / mechanical method such as a suspension coating method may be used. A preferred microencapsulation method is a gelatin-based film agent (for example,
Examples thereof include a gelatin-arabic gum film agent, a gelatin-carboxymethyl cellulose film agent) phase separation method, and an in-situ polymerization method using a melamine-formaldehyde resin.

As a method for forming a photosensitive layer containing a photochromic compound dissolved or dispersed in a resin or a microcapsule on a substrate,
A general coating method such as a doctor blade method, a casting method, a spinner method or a dipping method is used. The light-sensitive material of the present invention thus obtained generally has a film thickness of 0.5 µ to 1.0 mm, preferably 5 µ to 100 µ.

Needless to say, the light-sensitive material of the present invention may contain various additives such as a hindered amine light stabilizer, an ultraviolet absorber and an antioxidant in the light-sensitive layer, if necessary. Next, an optical recording medium having a recording layer containing the photochromic compound used in the present invention will be described.

The optical recording medium used in the present invention basically comprises a substrate and a recording layer. If necessary, an undercoat layer may be provided on the substrate or a protective layer may be provided on the recording layer. Layers can be provided. The substrate used in the present invention may be transparent or opaque to the light used.

Examples of the material of the substrate material include general recording medium supports such as glass, plastic, paper, plate-shaped or foil-shaped metal, and among these, plastic is preferable from various points. Is. As for plastic,
Examples thereof include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, polysulfone resin and the like.

The thickness of the recording layer in the optical recording medium of the present invention is 100Å to 100 μm, preferably 1000Å to 1.
The thickness is preferably 0 μm. As the film forming method, a commonly used thin film forming method such as a vacuum vapor deposition method, a sputtering method, a doctor blade method, a casting method, a spinner method and a dipping method can be adopted.

For example, if necessary, a photochromic compound is used as a polyester resin, polystyrene resin, polyvinyl butyral resin, polyvinylidene chloride, polyvinyl chloride, polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, cellulose acetate, epoxy resin. ,
With a binder such as a phenolic resin, it is dispersed or dissolved in a solvent such as carbon tetrachloride, benzene, cyclohexane, methyl ethyl ketone, tetrachloroethane, etc., and coated on a suitable substrate to form a recording layer, or a photochromic compound is formed. By vapor deposition on a suitable substrate by a known vapor deposition method or a co-evaporation method with other compounds to form a recording layer, or by dissolving the photochromic compound in the solvent as described above and enclosing it in a glass cell or the like. As a result, the optical recording medium can be easily obtained.

In the case of forming the recording layer by the spinner method, the rotation speed is preferably 500 to 5000 rpm, and after spin coating, treatment such as heating or applying to solvent vapor may be performed depending on the case. As a coating solvent for forming the recording layer by a coating method such as a doctor blade method, a casting method, a spinner method, a dipping method, or a spinner method, a boiling point of bromoform, dibromoethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone or the like is used. Those having a temperature of up to 160 ° C are preferably used.

In order to improve the stability and light resistance of the recording layer, a transition metal chelate compound (eg, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α-diketone, etc.) is used as a singlet oxygen quencher. ) Or a tertiary amine compound may be contained. The recording layer of the optical recording medium may be provided on both sides of the substrate, or may be provided on only one side.

[0034]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. [Synthesis Example] Synthesis of fulgenolide compound used in Example 1 As a raw material, indolyl fulgide known in the literature was used and synthesized according to the following route. All reactions were performed under a yellow fluorescent lamp containing no ultraviolet light.

[0035]

[Chemical 6]

208.7 mg (0.6185 mmol) of indolyl fulgide, (R) were placed in a 50 ml eggplant-shaped flask.
-(+)-2,2'-bihydroxy-1,1'-binaphthyl ((R) -2,2'-binaphthol) 213.6 m
g (0.7554 mmol) was charged and the atmosphere was replaced with nitrogen, 20 ml of tetrahydrofuran was added, and the mixture was cooled to 0 ° C. in an ice bath. 54.5 mg (1.3625) of sodium hydride (60% oily)
mmol) was added and stirred for 1 hour. 2 mol dm ^-3
Hydrochloric acid was added to acidify the reaction system, and organic matter was extracted three times with diethyl ether. The organic layer was washed with saturated brine and dried over anhydrous sodium sulfate. The desiccant was filtered off and the solution was concentrated, resulting in the precipitation of half ester. The precipitate is filtered off and dried to give crude crystalline half-ester.
7.1 mg (0.4923 mmol) was obtained from fulgide in a yield of 80%.

224.6 mg (0.3601 mmol) of half ester was placed in a 50 ml two-necked eggplant type flask, and the atmosphere was replaced with nitrogen, and 20 ml of tetrahydrofuran was added. 0.2 ml (1.4 mmol) of trifluoroacetic anhydride was added with a syringe and stirred for 10 minutes. After adding a saturated sodium hydrogen carbonate aqueous solution to the reaction system, the organic matter was extracted three times with diethyl ether. The organic layer was washed with saturated saline and dried over anhydrous sodium sulfate. After filtering off the desiccant, it was concentrated under reduced pressure and the product was isolated by flash column chromatography. Further, the product was purified by recrystallization from a mixed solvent of methylene chloride and hexane to obtain a fulgenolide compound in an amount of 121.4 mg (0.2004 mmol) and a half ester in a yield of 56%. The infrared absorption spectrum of the obtained fulgenolide compound was measured, and the horizontal axis represents wave number (cm ⁻¹ ) and the vertical axis represents transmittance in FIG.

Example 1 Experiments on a method of optical recording, nondestructive reading and erasing in a polymer using a fulgenolide compound will be described.

<Preparation of Optical Recording Medium> The frugenolide compound obtained in the above Synthesis Example was dispersed in a polymethylmethacrylate (hereinafter abbreviated as “PMMA”) film to prepare an optically recordable medium. That is, flugenolide compound 2
2.9 mg, PMMA 420 mg, methylene chloride 5 ml
2 ml of the solution was poured into a flat petri dish having a diameter of 4 cm. The petri dish was kept horizontal and left at room temperature for 2 days under light shielding to evaporate methylene chloride to obtain a film. The film was peeled from the petri dish and vacuum dried. In the light irradiation experiment, the film was used by fixing it on a glass substrate.

<Optical recording, reading and erasing method> First, the optical rotation is -0.0 when measured in a colorless state without light irradiation.
It was 18 degrees. Upon irradiation with 366 nm light (30 mWcm ^-2 ), a photochromic reaction occurred to produce a colored body, and the optical rotation was -0.009 degrees. It was confirmed by measuring the absorption spectrum that the photochromic reaction did not proceed in the film in measuring the optical rotation. Next, visible light with a wavelength of 470 nm or more (40 mW
When cm ^-2 ) is irradiated, all colored bodies return to colorless bodies,
The optical rotation was -0.026 degrees. Then 366 nm
Repeated irradiation with light and visible light reversibly changed the optical rotation. This state is shown in FIG. From the above,
It was shown that writing, erasing, and nondestructive reading were possible as a recording material.

Example 2 A method of non-destructive reading and erasing using the difference in optical rotation before and after the photochromic reaction of optically active indolyl fulgide will be described.

<Preparation of Indolinoflugide Toluene Solution> Yokoyama et al. Have already published a document (Chem. Let.
t (1994) 225) indolinofulgide is synthesized,
Optical resolution was performed by liquid column chromatography equipped with a column having cellulose tris (3,5-dimethylphenethylcarbamate) as a carrier. Indolinofurgide having an isopropyl group shown below did not show racemization.

<Optical recording, reading and erasing method> The photochromic reaction of the obtained indolyl fulgide is shown by the following formula.

[0044]

[Chemical 7]

The specific rotation at 589 nm of [II] in the toluene solution before irradiation with ultraviolet light was -529 degrees, and was 5600 degrees in the photosteady state of the photocyclization reaction due to ultraviolet light. (It was confirmed separately that the ring-closed compound III was also an optically active compound by tracking it with liquid chromatography.) Also, even if a wavelength with no absorption (> 760 nm) was used in any case, [XI] and [XII] It was confirmed from the spectrum that the above photoreaction does not proceed with this light, because the difference in the optical rotation of is large and the positive and negative are different. With visible light, [XII] becomes [X
I]. Thus, non-destructive reading was achieved by writing with ultraviolet light, erasing with visible light, and difference in optical rotation of light without absorption.

[0046]

The nondestructive read method using the optical rotation difference of the present invention is a non-contact type read method using light.
It is extremely useful as a reading method for a light-sensitive material and an optical recording medium.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of a fulgenolide compound obtained in a synthesis example.

FIG. 2 is a diagram showing a change in optical rotation with repeated irradiation of 366 nm light and visible light.

Claims (1)

[Claims] 1. A nondestructive reading method for a photosensitive material or an optical recording medium using a photochromic compound, comprising:
A non-destructive readout method characterized in that a compound having a difference in optical rotation between a reaction product and a product before and after photoreaction is used as the photochromic compound, and information is reproduced by using the difference in optical rotation.