JPS62162252A - Optical recording and reading method - Google Patents

Abstract

PURPOSE:To miniaturize a device and to carry out high-speed and high- resolution recording and reproduciton by using radiation for writing on an optical recording medium having a recording layer contg. a polydiacetylene derivative compd. and a specified diene compd. salt, and using the light having a shorter wavelength than the radiation for reading. CONSTITUTION:A soln. obtained by adding >=1 kinds of compd. shown by the general formula (1) or (2) to a polydiacetylene derivative compd. is coated on a discoid substrate made of glass and dried to form an optical recording medium. UV rays of 254nm are uniformly and sufficiently irradiated on the optical recording medium to polymerize the DA compd. in the recording medium to convert the recording layer into a blue film. Meanwhile, a semiconductor laser or a light emitting diode 10 radiating visible radiation in the region of wavelength in the range 550-750nm is used as an information reading means. A semiconductor laser 2 radiating IR in the region of wavelength in the range 800-900nm is used as the information writing means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording/reading method for an optical recording medium containing a polydiacetylene derivative compound. The present invention relates to an optical record reading method using visible light of 550 to 750 nm as a reading means.

[Conventional technology]

Recently, optical fibers have been attracting attention as a central player in office automation. Optical discs can store large amounts of documents, literature, etc. on a single disc, so
Organize and manage documents, etc. in the office efficiently. Various types of recording media have been considered for this optical disc, but those using organic materials are attracting attention because of their cost and ease of manufacture.

Diacetylene derivative compounds are known as organic materials for such recording media. Focusing on the thermochromic properties of these compounds, a recording technology for use as laser recording media was disclosed in Japanese Patent Application Laid-Open No. 147807/1983. There is. However, this specification does not mention what kind of laser was used or should be used, and merely states that recording was performed using a laser.

The present inventors investigated laser recording of this diacetylene derivative compound using various lasers, and found that although thermochromic recording is possible using a large, high-output laser such as an argon laser, a small and relatively It has been confirmed that laser recording cannot be performed when a low-power semiconductor laser (wavelength of 800 to 900 nm) is used. However, for a practical recording medium such as an optical disk, it is required that optical writing is possible using a small, low-output semiconductor laser, and reading can be performed using a light emitting diode or a small laser.

On the other hand, JP-A-59-842/18 and JP-A-84249
The issue discloses an organic coating containing a salt of a diene compound with a specific structure that has good thermal stability.These organic coatings absorb radiation in the radiation wavelength range of a semiconductor laser and generate heat, so laser energy can cause pit formation. It is disclosed that so-called heat mode recording can be carried out to form a .

However, when performing recording by forming physical pits on the surface of a recording medium, it is necessary to ensure that the initial surface of the recording medium is sufficiently smooth and at the same time that the surface of the recording medium is not scratched even after recording. In addition to requiring sufficient care, it is particularly difficult to perform high-density, high-sensitivity, and high-speed optical writing and to read the written records with good accuracy.

[Problem that the invention seeks to solve]

The present invention has been made in order to solve the problems of the prior art, and the purpose of the present invention is to enable optical writing using a small and lightweight semiconductor laser, and to read data by light irradiation with a small and lightweight visible light emitter. The object of the present invention is to provide an optical recording reading method that enables the following.

Another object of the present invention is to provide an optical recording/reading method that enables high-density, high-sensitivity, high-speed recording, and high-speed, highly accurate reading.

Still another object of the present invention is to provide an optical recording reading method that is excellent in stability and can obtain high-quality optically recorded images.

[Means for solving problems]

That is, the optical recording reading method of the present invention comprises a polydiacetylene derivative compound and the following general formula (1) or (2).
A step of irradiating an optical recording medium having a recording layer containing one or more of the compounds represented by the following with infrared rays of 800 to 10Q nm according to recorded information to discolor the irradiated area of the recording layer; It is characterized by comprising a step of irradiating the discolored portion of the layer with visible light of 550 to 750 nw to read recorded information.

General formula (1) General formula (2) 1(-" (wherein, R1 represents an alkyl group, a phenyl group that may have a substituent, or a styryl group, and R2 and R6 are
R
3 and R7 represent a phenyl group or a naphthyl group which may have a substituent, R4 represents an alkoxy group,
R5 represents an alkyl group, and A represents an anion residue. ) The polydiacetylene derivative compound contained in the optical recording medium used in the method of the present invention is a diacetylene derivative compound represented by the following general formula (hereinafter abbreviated as DA compound). In the formula, R8 and R9 are a polar group; an alkyl group that may be substituted with a polar group, a saturated aliphatic group such as a cyclohexyl group, a hydrogen group; a vinyl group, a propenyl group that may be substituted with a polar group; or an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, or an alkylphenyl group, which may be substituted with a polar group; examples of the polar group include a carboxyl group. or its metal or amine salt, sulfonic acid group or its metal or amine salt, sulfamide group, amide group, amino group, imino group, hydroxy group, oxyamino group, diazonium group, guanidine group, hydrazine group, phosphoric acid group, silicon (including acid groups, tetraaluminate groups, nitrile groups, thioalcohol groups, nitro groups, and halogen atoms), and is usually used in the production of optical recording media in the form of DA compounds. The polymer is incorporated into a recording medium, and prior to recording, it is polymerized by irradiation with ultraviolet rays and used for recording.

- The compound represented by the general formula (1) or (2) used in the present invention (hereinafter abbreviated as diene compound salt)
is a compound that has an absorption peak in a wavelength range of 750 nm or more and generates heat when exposed to infrared light of this wavelength.

To explain this diene compound salt more specifically, in the general formulas (1) and (2), R1 is an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, or phenyl which may have a substituent. or styryl group. Here, the substituents include methoxy, ethoxy,
Examples include alkoxy groups such as butoxy, halogen atoms such as chlorine, bromine, and iodine, alkyl groups such as methyl, ethyl, propyl, and isopropyl, and nitro groups. R2 and R
6 represents an arylene group which may have a substituent that forms a military double bond system with two adjacent -CH=CH- groups, such as p-phenylene and 1,4-naphthylene. Here, substituents include halogen atoms such as chlorine, bromine, and iodine;
Examples include alkyl groups such as methyl and ethyl, and alkoxy groups such as methoxy and ethoxy.

R3 and R7 represent a phenyl group or a naphthyl group which may have a substituent. Examples of substituents include substituted amino groups such as dimethylamino, diethylamino, dipropylamino, dibutylamino, diphenylamino, phenylamino, phenylbenzylamino, and phenylethylamino, cyclic amino groups such as morpholino, piperidinyl, and pyrrolidino, methoxy, ethoxy, Examples include alkoxy groups such as butoxy. R4 represents an alkoxy group such as methoxy, ethoxy or butoxy. R5 represents an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl or hexyl. A is an anionic residue, such as BFp, C18, c
p3c pig PF? , 'a, F? 1. Color (:1SOP
, toll3S5, C2H55ORC3H7soPc4
H9so? c5H1,5oPe θ C6H13503, C) I3CHCISO3, ClCH
2CH25O color"035CH250';', eO
3SCH2co,, s龜e03 S to H2CH2CH2
CI(2CH2CH25F?s, e03SCH2(
:R20(:H2CH2SO3, specific examples of this diene compound are illustrated below.

The optical recording medium used in the present invention contains the polydiacetylene derivative compound and the diene compound salt,
Specific configurations of the optical recording medium include the following aspects. However, the polydiacetylene derivative compound is expressed here in the form of a DA compound before polymerization.

(1) A recording layer constituting an optical recording medium or one containing a mixture of a DA compound and a diene compound salt (single-layer mixed system).

(2) The recording layer constituting the optical recording medium consists of two layers: a layer containing a DA compound and a radiation absorption layer containing a diene compound salt (two-layer separation system).

(3) The recording layer constituting the optical recording medium is composed of an alternating multilayer structure (multilayer system) of a layer containing an IA compound and a radiation absorbing layer containing a diene compound salt.

In the two-layer separation system and the multi-layer system, the layer containing the DA compound and the radiation absorbing layer containing the diene compound salt may be stacked in the order in which either one is located on the surface side of the recording layer. If necessary, various protective layers may be provided on the recording layer configured in this manner.

As the substrate of the optical recording medium used in the present invention, various support materials such as glass, plastic plates such as acrylic resin, plastic films such as polyester, paper, and metal can be used. When performing recording, a material that transmits recording radiation of a specific wavelength is used.

To form a recording layer on a substrate, typically, a fine powder of a DA compound and/or a diene compound salt is dispersed or dissolved in a suitable volatile solvent to prepare a coating solution, and this coating solution or these coatings are A method of applying a liquid onto the substrate can be adopted. Various binders made of natural or synthetic polymers may be appropriately added to the coating liquid in order to improve the adhesion to the substrate or between each layer. Furthermore, various additives may be added to improve the stability and quality of the recording layer.

Suitable binders can be selected from a wide variety of resins. Specifically, cellulose esters such as nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, cellulose valmitate, cellulose acetate propionate, cellulose acetate butyrate; methylcellulose, ethylcellulose Cellulose ethers such as , propyl cellulose, butyl cellulose; polystyrene, polyvinyl chloride, polyvinyl acetate,
Vinyl resins such as polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyvinylpyrrolidone; Copolymer resins such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer: polymethyl Acrylic resins such as methacrylate, polymethyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile; Polyesters such as polyethylene terephthalate; Poly(4,4'-isopropylidene diphenylene-1,4- cyclohexylene dimethylene carbonate), poly(ethylenedioxy-3,
3'-phenylene thiocarbonate), poly(4,4'
-isopropylidene diphenylene carbonate coated terephthalate), poly(4,4'-isopropylidene diphenylene carbonate), poly(4,4'-5ee
-butylidene diphenylene carbonate), poly(4,
Polyarylate resins such as 4'-isopropylidene diphenylene carbonate-block-oxyethylene): polyamides; polyimides; epoxy resins; phenolic resins; and polyethylene, polypropylene,
Polyolefins such as chlorinated polyethylene can be used.

The solvent used for coating is appropriately selected depending on the type of binder used and whether the DA compound and diene compound salt are contained in the binder in a dispersed state or in an amorphous state. Suitable solvents for salts include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; aliphatic nitriles such as acetonitrile; chloroform, methylene chloride, dichloroethylene, and carbon tetrachloride. , aliphatic halogenated hydrocarbons such as trichlorethylene, etc., and methylene chloride and acetonitrile are particularly preferred.

Suitable dispersion media for the DA compound include long-chain normal hydrocarbons and aliphatic halogenated hydrocarbons such as carbon tetrachloride.

However, since the DA compound is a compound with strong crystallinity, even if it is once dissolved in a solvent and this solution is applied onto a substrate, recrystallization proceeds during the drying process and dhalein is obtained. Therefore, not only dispersions but also solutions of DA compounds may be used. As the solvent in this case, the same solvents as those mentioned as the solvent for the diene compound salt can be used.

Application of such a coating liquid to a substrate can be performed using spinner rotation coating method, dip coating method, spray coating method, bead coating method, wire-har coating method,
Techniques such as a blade coach ink method, a roller coating method, and a curtain coating method are used.

When the recording layer is a mixed layer, the film thickness is 5.
Approximately 1000 to 2000 people is suitable, especially 1000 to 500
A range of 0 people is preferred. The mixing ratio of the DA compound and the diene compound salt in the recording layer is preferably about 1/15 to 15/1, and optimally 115 to 1/1.

In addition, in the case of a two-layer separation system, the appropriate film thickness for each layer is approximately 100 to 111,111 layers, especially 20 to 111,111 layers.
A range of 0 to 5,000 people is preferred.

In the case of a multilayer system, the total thickness of each compound layer and the total thickness of each diene compound salt layer are preferably about 100 to IJLII+, especially 200 to 500.
A range to 0 is preferred.

In the optical recording/reading method of the present invention, in the recording medium configured as described above that is used for recording and reproduction, the DA compound in the recording layer is first polymerized before recording is performed.

That is, the compound D is initially almost colorless and transparent, but when the entire recording layer is irradiated with ultraviolet rays, it polymerizes and changes into a polydiacetylene derivative compound. This polymerization occurs by irradiation with ultraviolet rays, etc., and cannot occur simply by applying thermal energy. As a result of this polymerization, the recording layer has a 620 to 66
The maximum absorption wavelength is at 0 nm, and the color changes from blue to dark. This change in hue due to polymerization is an irreversible change, and once the recording layer changes from blue to dark, it does not return to a colorless transparent film. In this way, D in the recording layer
An optical recording medium having a blue or darkened recording layer in which the compound is polymerized and changed into a polydiacetylene derivative compound is used in the method of the present invention.

When this polydiacetylene derivative compound that has changed from blue to dark color is heated to about 50°C or higher, it changes to about 540 nm.
It has a maximum absorption wavelength at , and the color changes to red. This change is also an irreversible change.

The optical record reading method of the present invention performs optical writing and optical record reading using the color changing properties of such polydiacetylene derivative compounds.Hereinafter, the optical record reading method of the present invention will be described in detail. .

FIG. 1 is a schematic diagram showing an example of an optical recording/reproducing apparatus used to implement the optical recording/reading method of the present invention. This optical recording/reproducing apparatus includes an optical recording medium mounting means (not shown) for setting the optical recording medium 1 at a predetermined position, an information writing means for writing information to the optical recording medium, and an information writing means for writing information to the optical recording medium. It consists of an information reading means for reading the recorded information. Information writing means is 800
A semiconductor laser 2 that emits ultraviolet light with a wavelength within the range of ~900r+m, a control circuit 3 that controls the oscillation of the semiconductor laser 2 according to human input information, and an optical system (collimating lens 4, dichroic mirror 5, reflector 6, wavelength plate) 7) and an objective lens 8). The semiconductor laser 2 is a GaA laser with an output wavelength of 820 to 840 r+m.
s welding laser, such as HLP-1500 (trade name,
Newly manufactured by Hitachi, output wavelength 830nm, maximum output 10mW
) is preferably used.

On the other hand, the information reading means is controlled by a drive circuit 9 and includes a semiconductor laser or light emitting diode IO1 output circuit 1 that emits visible light with a wavelength in the range of 550 to 750 nm.
1 and an optical pickup optical system (most of the optical system is shared with the optical system for the information writing means, but it has a collimating lens 13 and a polarizing beam splitter 14 as unique features). )
It consists of

The semiconductor laser 10 is one that emits visible light with a wavelength in the range of 650 to 750 nm, for example, GaAlAs.
It is preferable to use a PN junction laser, and the light emitting diode IO is one that emits visible light in the wavelength range of 550 to 750 nm, such as GaAIP, G
Preferably, junction diodes such as aP, GaAlAs, etc. are used.

The input information is converted into an optical signal by the semiconductor laser 2 via the control circuit 3. This optical signal passes through an optical system, is placed on an optical recording medium mounting means, and is imaged at a predetermined position on an optical recording medium having a blue to dark-colored recording layer that rotates synchronously. The image formation position is the recording layer when the optical recording medium is a single-layer mixed system, and the radiation absorption layer containing a diene compound salt when the optical recording medium is a two-layer separation system. The polyacetylene derivative compound present at the imaging point (site) does not absorb the laser beam of this wavelength, but the diene compound salt absorbs this laser beam and generates heat. The heat generated by the diene compound salt is transmitted to the adjacent polyacetylene derivative compound, causing the polydiacetylene derivative compound to turn red. In this way, optical writing is performed by changing the color of the recording area on the recording layer in accordance with the manual information.

On the other hand, optical recording reading is carried out using a low power continuous excavation light emitted from a semiconductor laser or a light emitting diode IO emitting visible light with a wavelength in the range of 550-750 nm. This reading light has a low output and a wavelength outside the infrared region, so it does not cause the diene compound salt to generate heat. Therefore, no recording is performed during reading using this reading light. The reading light forms an image on the surface of the recording layer of the optical recording medium 1 and is reflected. However, the reflectance of this reading light is different between recorded areas (discolored areas) and non-recorded areas, so this reflected light is By applying the light to the light-receiving surface of the photodetector 12 through the light pickup optical system, the light is converted into an electrical signal, and the recording is read and reproduced via the output circuit 11.

In the above example, the optical recording medium is a disc-shaped disk (
Although an optical disc) was used, optical tapes, optical cards, etc. can also be used depending on the type of substrate that supports the recording layer containing the polydiacetylene derivative compound and diene compound salt.

〔Effect of the invention〕

The effects of the optical recording and reading method of the present invention are listed below.

(1) Since the recording layer contains a diene compound salt that absorbs infrared rays with a wavelength in the range of 800 to 900 nm,
Optical writing can be performed using a small and lightweight semiconductor laser that emits infrared rays in the range of 00 to 900 nm, and
It can be read using a small and lightweight semiconductor laser or light emitting diode that emits visible light in the wavelength range of 750 nm.

(2) Since this is a recording and reproducing method that utilizes changes in the hue of the recording layer due to light irradiation, it is possible to perform high-speed, high-density, and highly sensitive optical writing, and also to perform high-speed, high-precision optical reading.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 General formula c, 2H25-c=c-c=c-c8H16-c
1 part by weight of a fine crystal powder of a diacetylene derivative compound represented by oon and 1 part by weight of a diene compound salt represented by the above compound AIILI are added to 4 parts by weight of methylene chloride, and the mixture is sufficiently stirred to prepare a coating solution. did.

Next, a glass disk substrate (thickness 1.5 mm, diameter 2
00mm) is attached to a spinner coater, and a small amount of the coating liquid is dropped onto the center of the disk substrate, the spinner is rotated at a predetermined number of rotations for a predetermined period of time, and the coating is dried at room temperature.
Optical recording media were prepared in which the thickness of the coating film after drying on the substrate was 500, 1,000, and 2,000, respectively.

These optical recording media were uniformly and sufficiently irradiated with 254 nm ultraviolet rays to polymerize the DA compound in the recording layer, making the recording layer a blue film.

Recording was performed on these optical recording media using the recording apparatus shown in FIG. 1 under the following recording conditions according to manual information.

Semiconductor laser (HLP-1500, manufactured by Hitachi) Laser wavelength: 830 nm Laser beam diameter: 1 scale laser output 3 mW, laser beam irradiation time per 1 bit: 00 ns When the laser beam is irradiated on the surface of the blue optical recording medium, it is irradiated. The color changed to red, and records were written on it. To read the records, a semiconductor laser with a wavelength of 680 nm and an output of 1 mW was used as a reading light source, and its reflected light was received by a photodetector (PN junction diode).

Evaluation of record writing was carried out as follows. The recording density was determined by measuring the optical density of the recording (red) area. The resolution and sensitivity were determined by observing the correspondence between the recorded image and the laser beam diameter using a microscope, and a very good result was marked as ◎, while a good result was marked as O1 recording or a poor correspondence was marked as ×. Also, record reading is
Evaluation was made by measuring the carrier noise ratio (C/N ratio). The evaluation results are shown in Table 1.

Example 2 After uniformly and sufficiently irradiating the three types of optical recording media created in Example 1 with 254 nm ultraviolet rays to make the recording layer a blue film, the laser used for recording was changed according to manual information, and the following was done. Recording was performed under the recording conditions, and the recording was read in the same manner as in Example 1.

Semiconductor laser (HLP-7802, manufactured by Hitachi) Laser wavelength: 800 nm Laser beam diameter = 1 scale laser output 3 mW.

Laser beam irradiation time per 1 bit: 00 ns Recording was evaluated using the same criteria as in Example 1, and the evaluation results are shown in Table 1.

Example 3, Comparative Example 1.2 Recording and reading were carried out under the same conditions as in Example 1, except that the lasers used for recording were changed to those shown below. The evaluation of the records was carried out using the same criteria as in Example 1, and the evaluation results are shown in Table 1.

Example 3: Semiconductor laser (Ga-As laser (W
- heterostructure), prototype) Laser wavelength: 890 nm Comparative example 1: Semiconductor laser (Ga-As laser (W-
Heterostructure), prototype) Laser wavelength: 950 nm Comparative example 2: Xenon gas laser, laser wavelength: 7
52 nm Example 4 On the same glass disk substrate as used in Example 1, a coating solution obtained by dissolving 1 part by weight of a diene compound salt represented by compound/LI in 2 parts by weight of methylene chloride was used. Then, in the same manner as in Example 1, a coating film having a thickness of 1000 mm after drying was formed. Next, 1 part by weight of the crystalline fine powder of the diacetylene derivative compound used in Example 1 and 1 part by weight of nitrocellulose as a binder were mixed with 4 parts by weight of methylene chloride.
The coating liquid obtained by dispersing and dissolving in parts by weight was applied on the coating film of the diene compound salt in the same manner as before to a thickness of 1000 mm after drying.
An optical recording medium having a recording layer with a two-layer separation structure was created by forming a human coating film. After forming the recording layer of this optical recording medium into a blue film, recording and reading were carried out under the same conditions as in Example 1. The recording was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 A solution prepared by dissolving 1 part by weight of a diacetylene derivative compound and 1 part by weight of nitrocellulose in 4 parts by weight of methylene chloride was used as a coating liquid, but in the same manner as in Example 1, without using a diene compound salt. Created a recording medium. Recording was performed on and read from this recording medium under the recording conditions of Example 1 and Comparative Example 1.2, respectively.

The evaluation results are shown in Table 1.

Table 1 Comparative Example 4 Same as Example 1, except that the diacetylene derivative compound was not used, and a solution of 1 ffiffi part of diene compound salt and 1 part by weight of nitrocellulose dissolved in 4 parts by weight of methylene chloride was used as the coating liquid. The thickness of the recording layer was 1000 mm by the method of
Created a human optical recording medium.

Example 1 A semiconductor laser beam was directly applied to this optical recording medium according to the input information without irradiating it with ultraviolet rays.
Recording is written by irradiating the surface of the recording layer with a laser beam at a predetermined position on the surface of the optical recording medium with the same output as the wavelength and irradiation time (irradiation time: 500 ns to 5 μS/bit) to form bits. carried out. As a result, as a result of microscopic observation of this optical recording medium,
It was found that an irradiation time of 4 μs or more was required to clearly form one pit.

Example 5 General 2C,2H25-C=C-C:G-C8H,6-C
Instead of the diacetylene derivative compound represented by 0OH,
General formula C8H,7-CEC-CEC-C1H4-(:O
An optical recording medium was prepared in the same manner as in Example 1 except that a diacetylene derivative compound represented by OH was used. Recording and reproduction were performed on this recording medium under the same conditions as in Example 1. The evaluation results are shown in Table 2.

Examples 6 to 10 The same method as in Example 1, except that diene compound salts represented by compounds/L3.8.12.15 and 20 were used instead of the diene compound salt represented by compound A1. An optical recording medium was created. Recording and reproduction were performed on these optical recording media under the same conditions as in Example 1. The evaluation results are shown in Table 2.

Table 2

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a recording device used in the optical recording/reading method of the present invention. 1: Optical recording medium 2: Semiconductor laser 3: Control circuit 4: Collimating lens 5: Dichroic mirror 6: Reflector plate 7: Wave plate 8: Objective lens 9: Drive circuit lO22 ring conductor laser or light emitting diode 11: Output Circuit 12: Photodetector 13: Collimating lens 14: Polarizing beam splitter

Claims (1)

[Scope of Claims] 1) A polydiacetylene derivative compound and the following general formula (1)
) or one or more of the compounds represented by (2).
A step of irradiating infrared rays of 550 nm to 7 nm to change the color of the irradiated area of the recording layer according to recorded information;
An optical record reading method comprising the step of irradiating visible light of 50 nm to read recorded information. General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) General formula (2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(2) (In the formula, R^1 represents an alkyl group or a substituent. Represents a phenyl group or styryl group that may have R^2 and R^
6 represents an arylene group which may have a substituent that forms a conjugated double bond system with two adjacent -CH=CH- groups, and R^3 and R^7 have a substituent. R^4 represents an alkoxy group, R^5 represents an alkyl group, and A represents an anionic residue. )