JPS62141539A - Optical recording method - Google Patents

Abstract

PURPOSE:To enable high-speed recording with high sensitivity even when small- sized lightweight semiconductor laser is used, by combinedly incorporating an azulenium salt compound and a polydiacetylene deriv. compound into a recording layer. CONSTITUTION:An optical recording medium has a recording layer contg. a polydiacetylene deriv. compound and an azulenium salt compound having a skeleton represented by formula I (where each of R1-R7 is H, halogen or a univalent org. residue). Light is projected on the optical recording medium in accordance with information to be recorded to form pits in the projected parts. The azulenium salt compound (AZ compound) has an absorption peak in a wavelength range of >=750nm and generates heat under infrared light having >=750nm wavelength.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical recording method using an optical recording medium, and in particular, a method for high-speed pit recording with high density and high sensitivity even when using a low-output semiconductor laser. The present invention relates to an optical recording method that is possible and advantageous in terms of energy saving.

[Prior Art] Recently, optical recording media such as optical disks, optical cards, and optical tapes (hereinafter collectively referred to as optical disks) have been attracting attention as central players in office automation.

For example, optical discs have the advantage that a large number of documents can be efficiently organized and managed on one disc.

Such recording layers used in optical disk technology can store high-density information by forming optically detectable small dots (eg, Igm size) in the form of spiral or circular tracks.

A typical disk used in this optical disk technology is one in which a recording layer made of a material sensitive to laser is provided on a substrate. In order to write information on the disk in the future, a laser beam focused on the laser sensitive layer (recording layer) is scanned, Vy' dots are formed only on the surface irradiated with the laser beam, and these dots are twisted according to the recorded information. or in the form of circular tracks.

That is, the laser sensitive layer can absorb laser energy to form optically detectable dots. For example, in the heat mode recording method, the laser sensitive layer absorbs thermal energy and can form dots consisting of small pits due to evaporation or melting at that location.

In another heat mode recording method, absorption of irradiated laser energy can form optically detectable discolored dots at the locations.

The information recorded on this optical disk is detected by scanning a laser along a track and reading the optical changes in the areas where dots are formed and the areas where dots are not formed. When using a disc with a recording layer provided on the surface, a laser is scanned along the track, and the energy reflected by the disc is reflected by the disc.In the case of pit recording, no pits are formed. By the way, the output of the photodetector decreases, whereas in areas where pits are formed, the laser beam is sufficiently reflected by the reflective surface of the underlying layer, and the output of the photodetector increases.

Conventionally, various types of recording layers for such optical disks have been used, including those mainly using inorganic materials such as metal TIs such as aluminum vapor-deposited films, bismuth IN, tellurium oxide IS, and chalcogenide-based amorphous glass films. It has been considered, but the price! Products made from organic materials are attracting attention because of their ease of construction.

As organic materials used for optical recording media, Japanese Patent Application Laid-Open No. 59-5
It is known from Japanese Patent No. 3850 that various azulenium salt compounds are absorbed and generate heat, so that so-called heat mode recording can be performed in which pits are formed using laser energy.

[Question to be Solved by the Invention, Point of Interest] However, in the conventional pit recording method, the recording is clear. That is, although it has the advantage of good contrast, it has the disadvantages that it requires more energy for recording and has a slower recording speed than a recording method that forms dots by discoloration.

Furthermore, since physical pits are formed on the surface of the recording medium, it is necessary to ensure that the initial surface of the recording medium is sufficiently smooth and at the same time, sufficient care must be taken not to damage the surface of the recording medium even after recording. Moreover, it has been difficult to perform high-density, high-sensitivity recording.

For example, when forming the recording layer of the above-mentioned 7-azulenium optical recording medium, the azulenium salt compound absorbs a semiconductor laser beam (infrared! 5K) and generates heat, and as a result of the heat generation, it self-melts. can be used to form pits in an optical recording medium.

However, it requires a large amount of energy to form pits, has low sensitivity, and requires a relatively long exposure time. Therefore, it was not possible to shorten the exposure time and recording at higher speeds was not possible.

The present invention was made to solve these conventional problems, and the present inventors formed a recording layer on an optical recording medium by combining an azulenium salt compound and a polydiacetylene derivative compound. The present invention was completed based on the discovery that the pit formation speed with light irradiation is significantly accelerated even when a high output semiconductor laser is used.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical recording method that enables optical writing using a small, lightweight, and low-output semiconductor laser and also enables high-speed recording.

Another object of the present invention is to provide an optical recording method capable of recording at high density and high sensitivity.

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

[Means for solving problems] The above object is achieved by the present invention as follows.

That is, the present invention provides a polydiacetylene derivative compound;
An optical recording medium having a recording layer containing an azulenium salt compound having a skeleton represented by general formula (I) is irradiated with light according to recorded information to form pits consisting of concave portions in the irradiated area. This is an optical recording method characterized by including a step of forming.

[Function] ゛The diacetylene derivative compound (hereinafter abbreviated as DA compound) contained in the optical recording medium used in the method of the present invention is the following general formula % formula % (wherein R and R are polar group; a saturated aliphatic hydrocarbon group such as an alkyl group or cyclohexyl group which may be substituted with a polar group; an olefinic hydrocarbon group such as a vinyl group or propenyl group which may be substituted with a polar group; or An aromatic hydrocarbon group such as a phenyl group, a naphthyl group, or an alkylphenyl group that may be substituted with a polar group. Examples of the polar group include 1, such as a carboxyl group or a metal or amine salt thereof, or a sulfonic acid group. or a metal or amine salt thereof, a sulfamide group, an amide group, an amino group, an imino group, a hydroxy group, an oxyamino group, a diazonium group, a guanidine group, a hydrazine group, a phosphoric acid group,
These include silicic acid groups, aluminic acid groups, nitrile groups, thioalcohol groups, nitro groups, and halogen atoms) and their polymers (polydiacetylene compounds).

Furthermore, as will be described later, in the case where the recording layer is formed from a monomolecular cumulative film, the DA compound has C=C-C in adjacent molecules.
"A compound capable of 11.4-addition polymerization reaction between the C functional groups, typically the following general formula 8%) (wherein, X is a xylophilic group forming a xylophilic site,
(2), n represents an integer).

Examples of the hydrophilic group X in this case include a carboxyl group, an amino group, a hydroxy group, a nitrile group, a thioalcohol group, an imino group, a sulfonic acid group, a sulfinyl group, or a metal or amine salt thereof. The alkyl group represented by H(OH,) forming the hydrophobic site is preferably a long-chain alkyl group having lθ to 30 carbon atoms, and m+n is suitably an integer of 10 to 3o.

On the other hand, an azulenium salt compound (hereinafter referred to as "azulenium salt compound") having a skeleton represented by the general formula (I) used in the present invention is used in the present invention.

(abbreviated as AZ compound) is a compound that has an absorption peak in a wavelength range of 750 nm or more and generates heat by infrared rays of this wavelength.

The AZ compounds containing the general formula (I) can be classified into three primary types.

(II) to (IV) are compound nitrides, R1-R
11C represents a water atom, a halogen atom, or a monovalent organic residue.

Monovalent organic residues include alkyl groups, alkoxy groups,
Mention may be made of substituted or unsubstituted aryl groups, acyl groups, substituted or unsubstituted amino groups, nitro groups, hydroxy groups, carboxyl groups, cyano groups or substituted or unsubstituted arylazo groups.

A represents a divalent organic residue bonded via a double bond, and specific examples thereof are shown below.

Zo represents a 7-ionic residue such as verchlorate, fluoroborate, p-)luenesulfonate, perfiodide, chloride, bromide or iodide.

Specific examples of the AZ compound used in the present invention are shown below.

tt3 A typical configuration of an optical recording medium used in the present invention is shown in FIG. 1. In this example, a recording layer 2 containing the DA compound and AZ compound is provided on a substrate 1.

The recording layer 2 of the optical recording medium used in the present invention has the above-mentioned O
Contains A compound and AZ compound, typically,
A coating solution is prepared by dissolving the crystalline fine powder of the DA compound and the AZ compound in a suitable volatile solvent, and this coating solution is applied onto the substrate, or a mixed monomer of the OA compound and the AZ compound is coated on the substrate E. It can be obtained by a method such as forming a molecular film or a mixed monomolecular cumulative film.

As the substrate 1 of the optical recording medium used in the present invention, glass,
When recording is carried out using polyurethane irradiation, a plastic plate made of acrylic resin is used that transmits recording radiation of a specific wavelength.

[
7! When forming the recording layer lt2, a binder made of natural or synthetic polymer may be added to the coating liquid as appropriate to improve the adhesion with the substrate l.
Various additives may be added to improve stability and quality.

The solvent used for coating is appropriately selected depending on the type of binder used and the types of DA compound and AZ compound, but in general, alcohols such as methanol, ethanol, and impropatol, acetone, methyl ethyl ketone,
Ketones such as cyclohexanone, NN-dimethylformamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, methyl acetate, ethyl acetate, butyl acetate, etc. Esters, chloroform.

Examples include aliphatic halogenated hydrocarbons such as methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, and aromatic hydrocarbons such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene.

The application of such a coating liquid to the substrate IJ: can be performed by a spinner rolling coating method, a dip coating method, a spray coating method, a pea coating method, a wire bar coating method, a blade coach ink i1. Techniques such as a roller coach ink method and a curtain coating method are used.

In this case, the thickness of the recording layer 2 is suitably about 5ooX to 2μ, particularly preferably in the range of 1000 to 5000'A.

The mixing ratio of the DA compound and the AZ compound in the recording layer z is 1/
Approximately 15 to 1571 is preferable, and optimally 1/10 to 5
/1.

On the other hand, a typical structure of an optical recording medium used in the method of the present invention in which the recording layer 2 is formed of a monomolecular film or a monomolecular cumulative film is illustrated in FIGS. 4 and 5.

FIG. 4 shows the OA compound 7 and the AZ compound 6 on the substrate 1k.
The recording layer 2 is formed of a mixed monomolecular film of
FIG. 5 shows a mixture of these monomolecular films (a).

To form the Q layer 2 consisting of such a monomolecular film or a monomolecular cumulative film on the substrate 1, for example, Hereinafter referred to as the 8-method) is used.

In the LB method, when a molecule has a parent wood group and a hydrophobic group in the molecule, and the balance between the two (amphiphilic balance) is maintained appropriately, the molecule is placed with the parent wood group facing down on the water surface. This is a method for creating a monomolecular film or a stacked a-molecular film of monomolecular layers. When the monomolecular layer on the water surface 1 has the characteristics of a two-dimensional system and 0 molecules are sparsely dispersed, the area per -molecule □ molecule A
The two-dimensional ideal gas equation, rlA = kT, holds true between and the surface an, resulting in a 'gas film', where k is Portzmann's constant and T is the absolute temperature.If A is made small enough, the intermolecular Interaction force: strengthens and becomes a two-dimensional solid "condensed film" (or solid material), which can be transferred layer by layer to the surface of a substrate such as glass.

Moreover, it consists of two or more compounds. The so-called mixed monomolecular film or mixed monomolecular cumulative film can be obtained by the same method as above. At this time, it is sufficient that at least one of the compounds 2 to E constituting the mixed monomolecular film or the mixed monomolecular film a has both a hydrophilic site and a hydrophobic site; It is not required to have both a lignophilic site and a hydrophobic site; in other words, as long as the amphipathic balance is maintained in at least one compound, a monomolecular film will be formed on the water surface, and other The compound is sandwiched between amphiphilic compounds, and a monomolecular layer with molecular order is formed as a whole.

Using this method, a mixed monomolecular film or a mixed monomolecular stack of an OA compound and an AZ compound constituting the recording layer of the present invention is produced, for example, as follows.

First, an OA compound and an AZ compound are dissolved in a solvent such as chloroform, and a developed layer in which these compounds are developed into a film is formed on the water surface.Next, this developed layer is allowed to freely diffuse on the water surface. Partition plate (or float) to prevent it from spreading too much
is provided to limit the developed area and control the state of aggregation of the membrane material, thereby obtaining a surface pressure n proportional to the state of aggregation. By moving this partition plate, the developed area is reduced and the aggregated state of the membrane material is
By controlling and gradually increasing the surface pressure, it is possible to set a surface pressure n suitable for producing a cumulative a film. By gently lowering the clean substrate vertically while maintaining this surface pressure, a mixed monomolecular film of a DA compound and an AZ compound is transferred onto the substrate. A mixed monomolecular film is produced in this manner, and a mixed monomolecular cumulative film having a desired degree of accumulation is formed by repeating the above operations.

In order to transfer the monomolecular film to the substrate, in addition to the vertical dipping method mentioned above, methods such as horizontal deposition method and single rotation cylinder method are used. The horizontal deposition method is a method in which substrates are brought into horizontal contact and transferred, and the rotating cylinder method is a method in which a cylindrical substrate is rotated above the water surface to transfer a monomolecular layer onto the surface of the substrate. In the vertical immersion method described above, when the substrate is raised in a direction across the water surface, a monomolecular layer is formed on the substrate with the parent wood groups facing the substrate in the first layer. As mentioned above, when the substrate is moved up and down, the monomolecular layers are overlapped one by one in each process.The direction of the film-forming molecules is reversed in the pulling process and the dipping process, so this method In this case, a Y-shaped film is formed in which parent wood groups and parent wood groups, and hydrophobic groups face each other.

On the other hand, the horizontal deposition method is a method in which the substrate is brought into horizontal contact with the water surface and transferred, and a monomolecular film with hydrophobic groups facing the substrate is formed on the substrate. In this method, there is no change in the direction of the film-forming molecules even if they are accumulated, and an X-type film is formed in which the hydrophobic groups face the substrate in all layers. A side-facing cumulative film is called a Z-type film.

The rotating cylinder method is a method in which a cylindrical substrate is rotated with respect to the water surface to transfer a monomolecular film onto the surface of the substrate.

The method of transferring a monomolecular film onto a substrate is not limited to these methods, but when using a large-area substrate/substrate.

A method such as extruding the substrate from a substrate roll into a water tank may also be used. Furthermore, the orientation of the aforementioned parent wood group and hydrophobic group toward the substrate is a general rule, and can be changed by surface treatment of the substrate, etc.

The details of these monomolecular film transfer operations are already known, and are described, for example, in "New Experimental Science Course 1B Interfaces and Colloids J" (pp. 498-507, Maruzen fil).

In this way, the mixed monomolecular film or mixed monomolecular film M film formed on the substrate has a high density and a high degree of order, so the variation in light absorption depending on the location is extremely small. By configuring the recording layer with such a film, a recording medium having a high-density, high-resolution recording function capable of optical recording and thermal recording can be obtained depending on the functions of the DA compound and the AZ compound. .

In this case, the thickness of the recording layer is suitably 2OO' to 2IL, particularly preferably in the range of 400 to 5000λ.

What is the mixing ratio of the DA compound and the AZ compound in the recording layer?

This is the same as the case using the coating method described above.

Note that, if necessary, various protective layers may be provided on the Q layer configured as described above.

The optical recording method of the present invention can be carried out using a recording medium configured in this manner.

In this recording medium, by applying light to the OA compound, the absorption wavelength of the recording layer changes and the apparent color changes. That is, the OA compound is initially almost colorless and transparent, but upon irradiation with ultraviolet rays, it polymerizes and changes into a polydiacetylene derivative compound. This polymerization occurs only by ultraviolet irradiation and not by the application of other physical energy such as heat.
The maximum absorption wavelength is at 0 ns, and the color changes from blue to dark. The change in hue due to this polymerization is an irreversible change, and the recording layer that has changed to -.degree. blue does not return to a colorless transparent film.

Furthermore, when the recording layer containing the polydiacetylene derivative compound and the AZ compound, which has turned blue, is irradiated with a semiconductor laser, the AZ compound absorbs the light and generates heat, which melts the light-irradiated area of the recording layer. do. The energy required for melting at this time is significantly smaller than when the recording layer is formed using the AZ compound alone.

The recording method of the present invention performs recording by utilizing the characteristics obtained by the combination of such an OA compound and an AZ compound.

As the semiconductor laser used in the method of the present invention, it is particularly suitable to use a GamAs 11i combined laser with an output wavelength of 820 to 840 nm.

When carrying out the method of the present invention, D as an optical recording medium is used.
When using a recording layer containing the A compound and the AZ compound, first, the entire recording layer is irradiated with ultraviolet rays. By this irradiation with ultraviolet rays, the DA compound in the recording layer is polymerized and changed into a polydiacetylene derivative compound as described above, and the recording layer changes color into a blue film.

On the other hand, input information is converted into an optical signal by a semiconductor laser via a control circuit. This optical signal passes through an optical system and is placed, for example, on an optical recording medium aW1p stage, and is imaged at a predetermined position on the synchronously rotating recording medium as shown in FIG. The imaging position is the recording layer of the recording medium.

The AZ compound present at the imaging point (site) 3 absorbs this laser beam 4 and generates heat. Due to the heat generated by the AZ compound, the recording layer 2 at the imaging point 3 is melted, and pits consisting of recesses 5 are formed as shown in FIG. In this case, as described above, the recording layer 2 of the recording medium used in the present invention is composed of a combination of an AZ compound and a polydiacetylene derivative compound. : The aforementioned pit formation is greatly promoted.

Therefore, it has higher sensitivity than pits in a recording layer composed of only an AZ compound, and when a semiconductor laser of the same output is used, the exposure time with a laser beam can be shortened.

In this way, optical recording is performed by forming pits in the recording layer according to input information.

In the example described in L, the optical recording medium is disk 1 (
Although an optical disk (optical disk) was used, it can also be used as an optical tape, optical card, etc., depending on the type of substrate that supports the recording layer containing the OA compound and the AZ compound.

[Example] In order to explain the present invention more specifically, Examples are given below.

Example 1 C1zH21-C"C-C11C-C@H,1COO
Salercia acetylene derivative compound crystal fine powder 1
parts by weight and 1 part by weight of the azulenium salt compound represented by the above dye 11b, 1 were added to 4 parts by weight of methylene chloride and thoroughly stirred to prepare a coating solution.

Next, a glass disk substrate (thickness: 1.5 m3 diameter: 201 m5) was mounted on a spinner coater, and a small amount of the coating liquid was dropped onto the center of the disk substrate.

The coating was applied by rotating a spinner at a predetermined number of rotations for a predetermined time, and dried at room temperature, so that the dry film thickness on the substrate was 500A, 1
Recording media of 000A and 2000A were respectively created.

The recording medium thus obtained was first uniformly and sufficiently irradiated with 254n ultraviolet rays to turn QM into a blue film.

Next, a laser beam irradiation time of 500 nm per bit was applied to the recording medium having the recording layer in which the blue color was obscured.
Except for various changes between s and 5gm.

Optical recording was carried out under the following recording conditions.

Semiconductor laser wavelength: 830nm Laser beam diameter: lμ■ Laser output 3- After recording under the above conditions, the recording results on each recording medium were observed using a microscope, and the laser beam irradiation area was We investigated the laser beam irradiation time (sensitivity) required to form pits consisting of clear recesses. The results are shown in Table 1.

Next, the resolution and contrast ratio (sharpness) between pits and non-pits were comprehensively evaluated for the recording medium recorded with an irradiation time of 900ns/l pits.
Especially good ones are 0. A score of 0 indicates a good score, and a score of "x" indicates a record that cannot be recorded or is bad. The results are shown in Table 1.

Example 2 Same as Example 1 except that a mixed solution containing 5 parts by weight of diacetylene derivative compound, 1 part by weight of azulenium salt compound, and 12 parts by weight of methylene chloride was used as the coating liquid. A recording medium was obtained using the same method, and recording was performed on the medium for evaluation. .

The recording results are shown in Table 1.

Comparative Example 1 Diacetylene derivative compound 1 without using an azulenium salt compound! A recording medium was obtained in the same manner as in Example 1, except that a solution in which the lit part was added to 2 parts by weight of methylene chloride was used as the coating liquid, and recording was performed on the recording medium for evaluation. The recording results are shown in Table 1.

Comparative Example 2 A recording medium was prepared in the same manner as in Example 1, except that a solution of 1 part by weight of an azulenium salt compound dissolved in 2 parts by weight of methylene chloride was used as the coating liquid, without using a diacetylene derivative compound. This was recorded and evaluated. The recording results are shown in Table 1.

Example 3 The amount of the diacetylene derivative compound was 1 part by weight, the amount of the azulenium salt compound was 1 part by weight, the amount of methylene chloride was 4 parts by weight, and 2! A recording medium in which the jii layer had a thickness of 400 OA was produced in the same manner as in Example 1, except that the Iim portion was used as a binder.

This recording medium was uniformly and sufficiently irradiated with 254 n- ultraviolet rays to turn the recording layer into a blue film, and then recording was carried out under the following recording conditions according to the input information. The laser beam irradiation time per bit was varied between 500 ns and 5 ILS.

Semiconductor laser wavelength: 840 nm Laser beam diameter: 1 L Laser output 3 ■ Comparative Example 3 Without using a diacetylene derivative compound, part of the azulenium salt compound ZffltiL and 2 parts by weight of nitrocellulose were mixed with 4 parts by weight of methylene chloride. A recording medium was obtained in the same manner as in Example 3, except that a solution dissolved in . The recording results are shown in Table 1.

Regarding the recording medium of Example 3, as a result of microscopic observation, good recording could be performed when the irradiation time was 1000 ns/1 bit or more, but regarding the recording medium of Comparative Example 3, one pit 2000ns to clearly form
/ Required irradiation time of 1 bit or more.

Example 4 C,zHll-C"C-C"C-CN o,, -coo
In place of the diacetylene derivative compound represented by n Te, C
A recording medium was obtained in the same manner as in Example 1 except that a compound represented by NHI-1-CmC-C=C-CzH4-CO-OH was used, and optical recording was performed on this, and the recording results were was evaluated. The results are shown in Table 1.

Example 5 A recording medium was obtained in the same manner as in Example 4, except that an azulenium salt compound represented by dye No. 6 was used instead of an azulenium salt compound represented by dye No. 1, and optical recording was performed on it. The recorded results were evaluated. The results are shown in Table 1.

Example 6 1 part by weight of a diacetylene derivative compound represented by Ct2H2 to C-C-C-C-C9H1, -COOH and 1 part by weight of an azulenium salt compound represented by dye No. 1 were added to chloroform at 1 x 10 mol. The solution was developed with an aqueous phase having a pH of 8.5 and a cadmium chloride concentration of 1X10-' mol/l. After removing the solvent chloroform, while keeping the surface pressure constant, the glass substrate, which has been sufficiently washed and has a wood-friendly surface, is gently heated in a direction across the water surface at a hF rate of 1.0 cm for 1 minute.
A mixed monomolecular film of a diacetylene derivative compound and a 7-durenium salt compound was transferred to a substrate, and the mixed monomolecular film and 21 layers were formed at 41W! A recording medium was prepared in which a mixed monomolecular cumulative film of 81 layers was formed on a substrate.

Using the recording medium thus obtained, optical recording was carried out in the same manner as in Example 1, and the results were evaluated. The results are shown in Table 2. Example 7 Instead of the diacetylene derivative compound represented by C1zHA-CNC-CNC-C8H17-GOOR, c, o
A recording medium was obtained in the same manner as in Example 6 except that a compound represented by , &-ctc-c heavy C-C,H-C00H was used, optical recording was performed on this, and the recording result was was evaluated. The results are shown in Table 2. Example 8 Recorded in the same manner as in Example 6 except that the azulenium salt compound represented by dye No. 14 was used instead of the azulenium salt compound represented by dye No. 1. A medium was obtained, optical recording was performed on it, and the recording results were evaluated. The results are shown in Table 2.

Table 1 Table 1 (continued) Table 2 [Effects of the invention 1 The effects of the optical recording method of the present invention are listed below.

(I) Since the recording layer contains a combination of a heptadurenium salt compound and a polydiacetylene derivative compound, high sensitivity and high speed recording can be performed even using a small and lightweight semiconductor laser.

(2) Since the Q layer is formed uniformly and with good surface properties, it is possible to perform optical recording with excellent stability and high quality. Furthermore, when the recording layer is formed of a mixed monomolecular film or a single mixed monomolecular cumulative film of an azulenium salt compound and a polydiacetylene derivative compound, ``the recording layer has a higher density and a higher degree of order. Therefore, it is possible to record with higher density, higher resolution, and homogeneity.

(3) Optical recording using an inexpensive recording medium having a highly homogeneous, large-area recording layer becomes possible.

[Brief explanation of drawings]

Figure 1 shows the structure of the optical recording medium used in the method of the present invention.
Schematic cross-sectional views illustrating the embodiment, FIGS. 2 and 3,
FIGS. 4 and 5, which illustrate the optical recording process of the present invention, are schematic cross-sectional views of an optical recording medium used in the present invention, in which a recording layer is formed of a monomolecular film and a monomolecular stack 11. 1: Substrate 2: Recording layer 3: Light irradiation (description Q) portion 4: Laser beam 5: Pit 6: Azulenium salt compound 7: Diacetylene derivative compound

Claims (1)

[Claims] A polydiacetylene derivative compound and the following general formula (I
) A step of irradiating an optical recording medium having a recording layer containing an azulenium salt compound having a skeleton represented by the above with light according to recorded information to form pits consisting of concave portions in the irradiated area. An optical recording method characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 to R_7 represent hydrogen atoms, halogen atoms, or monovalent organic residues.)