JPH0475838B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an optical recording method using an optical recording medium, and in particular, a method that enables a combination of color change recording and pit recording, that is, ternary recording, on a single optical disk, and a low-output method. The present invention relates to an optical recording method that enables high-density optical recording even when using a semiconductor laser and is 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 disks have the advantage that a large amount of documents, literature, etc. can be efficiently organized and managed on a single disk. The recording layer used in such optical disk technology consists of optically detectable small dots (e.g.
High-density information can be recorded by forming a spiral (approximately 1 μm) into a spiral or circular track form. 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. To write information on this optical disk, a laser beam focused on the laser sensitive layer (recording layer) is scanned, dots are formed only on the surface irradiated with the laser beam, and the dots are shaped into a spiral or circular shape depending on the recorded information. In other words, the laser-sensitive layer absorbs laser energy and can form optically detectable dots.For example, in heat mode recording, the laser-sensitive layer absorbs thermal energy and forms optically detectable dots. In another heat mode recording method, a dot consisting of a small pit can be formed by evaporation or melting.In addition, in another heat mode recording method, a dot consisting of an optically detectable discolored area is formed at that location by absorption of the irradiated laser energy. The information recorded on this optical disk is detected by scanning a laser along the track and reading the optical changes in the areas where dots are formed and where they are not. For example, When a disk having a recording layer provided on a reflective surface of a substrate is used, a laser is scanned along a track and the energy reflected by the disk is monitored by a photodetector. In the case of pit recording, the output of the photodetector decreases in areas where pits are not formed, whereas in areas where pits are formed, the laser beam is sufficiently reflected by the reflective surface of the underlying layer. The recording layer of such optical disks has traditionally been made of inorganic materials such as metal thin films such as aluminum evaporated films, bismuth thin films, tellurium oxide thin films, and chalcogenite amorphous glass films. Various methods have been considered, including those using organic materials, but those using organic materials are attracting attention due to their cost and ease of manufacture.On the other hand, conventional heat mode methods either form dots or do not. Because of the binary recording, there was a limit in implementing higher-density recording. [Problems to be solved by the invention] The present invention was made to solve such conventional problems. The present inventors have discovered that by forming a recording layer on an optical recording medium by combining an azulenium salt compound and a diacetylene derivative compound, color change recording and pit recording are possible with one optical disc. The present invention has been completed by discovering that color change recording and pit recording can be performed at the same speed even when a low-power semiconductor laser is used. An object of the present invention is to provide an optical recording method that enables three-value recording using dots. Another 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, high sensitivity, and high resolution. 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 the Problems] The above objects are achieved by the following present invention. That is, the present invention has a recording layer comprising a monomolecular film of a diacetylene derivative compound having both hydrophilic and hydrophobic sites or a cumulative film thereof, and an azulenium salt compound having a skeleton represented by the following general formula (). An optical recording medium consisting of an optical recording medium is irradiated with ultraviolet rays, and then irradiated with light whose exposure amount is controlled according to the recorded information.The light with an exposure amount of Q ₁ causes discoloration, and the light with an exposure amount of Q ₂ causes a pit consisting of a recess. This is an optical recording method characterized by including a step of forming (Q ₁ <Q ₂ ). (In the formula, R ₁ to _{R 7} represent a hydrogen atom, a halogen atom, or a monovalent organic residue.) [Function] Hydrophilic site and hydrophobic site contained in the optical recording medium used in the method of the present invention Diacetylene derivative compound (hereinafter abbreviated as DA compound) used in combination with
is a compound capable of 1,4-load polymerization reaction between C≡C-C≡C functional groups in adjacent molecules,
Typically, the following general formula H( _CH2 ) _n -C≡C-C≡C-( _CH2 ) _o -X (wherein, X is a hydrophilic group forming a hydrophilic site, m, 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. H forming a hydrophobic site
The alkyl group represented by ( _CH2 ) ^-n is preferably _a long-chain alkyl group having 10 to 30 carbon atoms. Further, m+n is suitably an integer of 10 to 30. On the other hand, the azulenium salt compound (hereinafter abbreviated as AZ compound) having a skeleton represented by the general formula () used in the present invention has an absorption peak in a wavelength range of 750 nm or more, and generates heat by infrared rays of this wavelength. It is a compound. The AZ compound containing the above general formula () has the following 3
Can be classified into species. In the compounds shown in () to (), R ₁ to
R ₇ represents a hydrogen atom, a halogen atom, or a monovalent organic residue. Monovalent organic residues include alkyl groups, alkoxy groups, 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. can be mentioned. A represents a divalent organic residue bonded through a divalent bond, and specific examples thereof are shown below. Z is perchlorate, fluoroborate,
p-toluenesulfonate, periodide,
Represents an anionic residue such as chloride, bromide or iodide. Specific examples of the AZ compound used in the present invention are shown below. The optical recording medium used in the present invention contains a monomolecular film or a monomolecular cumulative film of the DA compound and an AZ compound, and may have a one-layer mixed system, a two-layer separated system, or a multilayer laminated system. . Here, the one-layer mixed system is one consisting of a mixed layer of DA compound and AZ compound, and the two-layer separated system is
A multilayer system is one in which a layer containing a DA compound and a layer containing an AZ compound are laminated separately.
This refers to a structure in which one or more layers containing a compound and one or more layers containing an AZ compound are laminated in a predetermined number of layers, and does not include the above-mentioned two-layer separation system. Typical structures of the optical recording medium used in the present invention are shown in FIGS. 1a and 1b and 2a and 2b. In FIGS. 1a and 1b, a single-layer mixed recording layer 15 is provided on a substrate 11, and in one embodiment, as shown in FIGS. 4a and 4b, a DA compound 16- A mixed monomolecular film of 1 and AZ compound 16-2 is formed, or DA compound 16-1
It consists of a mixed monomolecular cumulative film of AZ compound 16-2 and AZ compound 16-2. On the other hand, Figure 2 a and b show a two-layer separation system, i.e.
A recording layer 15 consisting of a layer 15-1 containing a DA compound and a layer 15-2 containing an AZ compound is provided on the substrate 11, and one embodiment is as shown in FIGS. 3a and 3b. A layer 21 containing an AZ compound is provided on a substrate, and a monomolecular film of a DA compound is further laminated thereon, or a monomolecular cumulative film of a DA compound is laminated on the layer 21 containing an AZ compound. It is something. Note that the layer 21 containing the AZ compound is, as described later,
It may be formed as a monomolecular film or a monomolecular cumulative film. As the substrate 11 of the optical recording medium used in the present invention, various materials such as glass, a plastic plate made of acrylic resin, a plastic film such as polyester, paper, and metal can be used. When performing recording, a material that transmits recording beams of a specific wavelength is used. It can be obtained by a method such as forming a mixed monomolecular film or a mixed monomolecular cumulative film of a DA compound and an AZ compound on the substrate 11. In order to form the recording layer 2 made of such a monomolecular film or a monomolecular cumulative film on the substrate 1, for example, I.
The Langmiur-Blodget method (monomolecular cumulative film formation method, hereinafter referred to as the LB method) developed by Langmiur et al. is used. The LB method is a molecule with a structure that has a hydrophilic group and a hydrophobic group within the molecule, and when the balance between the two (amphiphilic balance) is maintained appropriately, the molecule faces the hydrophilic group downward on the water surface. This method creates a monomolecular film or a cumulative film of monomolecular layers. A monolayer on the water surface has the characteristics of a two-dimensional system. When the molecules are sparsely dispersed, the two-dimensional ideal gas equation ΠA=kT holds true between the area A per molecule and the surface area Π, resulting in a "gas film." Here, k is Boltzmann's constant and T is absolute temperature. If A is made sufficiently small, the intermolecular interaction will be strengthened, resulting in a two-dimensional solid "condensed film (or solid film)". The condensed film can be transferred layer by layer to the surface of a substrate such as glass. Moreover, a so-called mixed monomolecular film or mixed monomolecular cumulative film composed of two or more compounds can also be obtained by the same method as described above. At this time, it is sufficient that at least one of the two or more compounds constituting the mixed monomolecular film or mixed monomolecular cumulative film has both a hydrophilic site and a hydrophobic site, and not all compounds necessarily have hydrophilic sites. It is not required that the hydrophobic site and the hydrophobic site be present together. In other words, if the amphipathic balance of at least one compound is maintained, a monomolecular film will be formed on the water surface, and the other compounds will be sandwiched between the amphipathic compounds, resulting in an increase in the overall molecular order. A monolayer is formed. The recording layer of the present invention is constructed using this method.
A mixed monomolecular film or a mixed monomolecular cumulative film of a DA compound and an AZ compound is produced, for example, as follows. First, a DA 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, to prevent this spread layer from spreading freely on the water surface and spreading too much, a partition plate (or float) is installed to limit the spread area and control the aggregation state of the membrane material, and the surface is proportional to the aggregation state. Obtain pressure Π. By moving this partition plate, the developed area can be reduced to control the aggregation state of the film material, and the surface pressure can be gradually increased to set a surface pressure Π suitable for producing a cumulative film. By gently vertically moving a clean substrate up and down while maintaining this surface pressure, a mixed monomolecular film of DA and AZ compounds is transferred onto the substrate. A mixed monomolecular film is produced in this manner, and a mixed monomolecular cumulative film is formed by repeating the above-mentioned operations to form a mixed monomolecular cumulative film with a desired degree of accumulation. In order to transfer the monomolecular film onto the substrate, in addition to the above-mentioned vertical dipping method, methods such as the horizontal deposition method and the rotating cylinder method can be 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 and a monomolecular layer is transferred onto the surface of the substrate. In the vertical immersion method described above, when the substrate is raised in a direction transverse to the water surface, a monomolecular layer in which the first layer has hydrophilic groups facing the substrate is formed on the substrate. When the substrate is moved up and down as described above, the monolayers are stacked one by one for each step. Since the orientation of the film-forming molecules is reversed between the pulling process and the dipping process, according to this method, a Y-shaped film is formed in which hydrophilic groups and hydrophobic groups and hydrophobic groups face each other between each layer. 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 when the films are accumulated, and an X-shaped film is formed in which the hydrophobic groups face the substrate in all layers. On the other hand, a cumulative film in which the hydrophilic groups in all layers face the substrate side is called a Z-type film. The rotating cylinder method is a method in which a cylindrical substrate is rotated above 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,
A method such as extruding the substrate from a substrate roll into a water tank may also be used. Furthermore, the directions of the aforementioned hydrophilic groups and hydrophobic groups toward the substrate are in principle, and can be changed by surface treatment of the substrate, etc. The details of these monolayer transfer operations are already publicly known, for example, in ``New Experimental Science Course 18''.
"Interfaces and Colloids" (pp. 498-507, published by Maruzen). In this way, the mixed monomolecular film or mixed monomolecular cumulative film formed on the substrate has a high density and a high degree of order, so variations in light absorption depending on the location are extremely small. Therefore, by configuring the recording layer with such a film, the DA compound and
Depending on the function with the AZ compound, a recording medium having a high density and high resolution recording function capable of optical recording and thermal recording can be obtained. In addition, when forming the recording layer 15 of a two-layer separation system or a multilayer stack system, one or more of the layers 13 and 14 consisting of a monomolecular film or a monomolecular cumulative film of a DA compound and one of the layers 21 containing an AZ compound. The above may be laminated on a substrate in a predetermined number of layers and in a predetermined order. In this case, the layers 13 and 14 consisting of a monomolecular film or a monomolecular cumulative film of the DA compound are formed on the substrate 11 or other layers by the above-mentioned LB method by preparing a developing solution containing the DA compound. can. The layer 21 containing the AZ compound is formed by coating the substrate 11 with a coating solution prepared by dissolving the AZ compound in a suitable volatile solution.
It can be formed by coating the layer on top or on other layers to a desired thickness and then drying it. Alternatively, a monomolecular film can be formed by using the LB method described above by using an organic polymer with an excellent balance of amphipathic properties as a carrier molecule in an arbitrary ratio to the AZ compound, such as a polymeric fatty acid such as stearic acid or arachidic acid. Alternatively, it can also be formed as a monomolecular cumulative film. When forming a layer containing an AZ compound by a coating method, solvents for forming a coating solution include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methylethyletone, and cyclohexanone, and aliphatic nitriles such as acetonitrile. Examples include aliphatic halogenated hydrocarbons such as , chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, with methylene chloride and acetonitrile being particularly preferred. Incidentally, a binder made of a natural or synthetic polymer may be added to the coating liquid as appropriate in order to improve the adhesion to the substrate 11 or other layers. Furthermore, various additives may be added to improve the stability and quality of the recording layer 15. Coating of such a coating liquid onto the substrate 11 can be performed by a spinner rotation coating method, a dip coating method, a spray coating method, a pea coating method, a wire bar coating method, a blade coating method, a roller coating method, a curtain coating method, etc. method is used. When the recording layer 15 is a single-layer mixed system, the film thickness is suitably about 200 Å to 2 μ, especially about 400 Å to 2 μ.
A range of 5000 Å is preferred. In addition, in the case of a two-layer separation system, the appropriate film thickness for each layer is approximately 100 Å to 1 μ.
Particularly preferred is a range of 200 to 5000 Å. Furthermore, in the case of a multilayer laminated system, it is suitable that both the sum of the film thicknesses of the layers containing individual DA compounds and the sum of the film thicknesses of the layers containing individual AZ compounds are about 100 Å to 1 μ;
Particularly preferred is a range of 200 to 5000 Å. The mixing ratio of the DA compound and the AZ compound in the recording layer 11 is preferably about 1/15 to 15/1, and optimally 1/10 to 10/1. Note that various protective layers may be provided on the recording layer configured in this way, if necessary. Furthermore, the present invention is applicable regardless of the order in which the layers are stacked in a two-layer separation system or a multilayer stack system. Note that various protective layers may be provided on the recording layer configured in this way, if necessary. 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 DA compound, the absorption wavelength of the recording layer changes and the apparent color changes. That is, the DA compound is
Initially, it is almost colorless and transparent, but upon irradiation with ultraviolet light, it polymerizes and transforms into a polydiacetylene-derived compound. This polymerization occurs only by ultraviolet irradiation and not by the application of other physical energy such as heat. As a result of this polymerization, it has a maximum absorption wavelength of 620 to 66 nm, and its color changes from blue to dark. This change in hue due to polymerization is an irreversible change, and once the recording layer changes to blue, it does not return to a colorless transparent film. Furthermore, the recording layer containing the polydiacetylene derivative compound and the AZ compound that turned blue,
It generates heat at a temperature that corresponds to the amount of light it is exposed to.
At that time, if the recording layer 15 is not melted and the polydiacetylene derivative compound is heated to about 50° C. or higher, the exposed portion of the recording layer will have a maximum absorption wavelength of about 540 nm, and the red film will change. and changes.
Note that this change to a red film is also an irreversible change. Further, when the exposure amount is increased and the exposure amount exceeds a certain limit, the exposed portion of the recording layer melts. The recording method of the present invention uses such DA compounds and
Recording is performed using the characteristics obtained in combination with AZ compounds. As the semiconductor laser used in the method of the present invention, it is particularly suitable to use a Ga/As junction laser with an output wavelength of 820 to 840 nm. When carrying out the method of the present invention, when using an optical recording medium having a recording layer containing a compound and an AZ compound, first,
The entire recording layer is irradiated with ultraviolet light. By this irradiation with ultraviolet rays, the DA compound in the recording layer polymerizes and changes 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, is placed on, for example, an optical recording medium mounting means, and is imaged at a predetermined position on the synchronously rotating recording medium, as shown in FIG. 1a. The imaging position is the recording layer 15 of the recording medium. The exposure amount at the imaging points (sites) 18-1 and 18-2 is such that the polydiacetylene derivative compound for color change recording is heated to about 50° C. or higher, but at a temperature that does not melt the recording layer 15. (Q ₁ ) and an amount (Q ₂ ) sufficient to melt the recording layer 15 for pit recording (however,
Q ₁ <Q ₂ ). In order to change the exposure amount of the imaging point in this way,
Methods such as changing the intensity of the semiconductor laser, changing the laser irradiation time, or using a combination of these may be used. Note that when performing irradiation with two types of exposure doses, the above control may be performed using one semiconductor laser, or multiple semiconductor lasers that can obtain different exposure doses may be used. . Exists at imaging points (parts) 18-1 and 18-2
The AZ compound is exposed to this laser beam 17-1,1
7-2 and generates heat. Here, the imaged point 18-1 that received the exposure amount of _Q1 mentioned above changes to red because the polydiacetylene derivative compound is heated by the heat generated by the AZ compound, and it can be distinguished from the blue color of the unexposed area. This results in a dot 19 consisting of a discolored portion. In addition, in an optical recording medium having a recording layer consisting only of a DA compound, the polydiacetylene derivative compound has no sensitivity to lasers with a wavelength of 800 to 850 nm, so when a semiconductor laser with this wavelength is used, , optical recording due to discoloration is impossible. On the other hand, the image forming point 1 that received the exposure amount of Q ₂ mentioned above
8-2 is melted by the heat generation of the AZ compound, and a pit consisting of a concave portion is formed as shown in FIG. 1b. At that time, the recording layer 15 of the recording medium used in the present invention
As mentioned above, since AZ is composed of a combination of an AZ compound and a polydiacetylene derivative compound, the presence of the polydiacetylene derivative compound can significantly reduce the energy required to melt the recording layer. The aforementioned pit formation by the compound is greatly promoted. In this way, optical recording, that is, ternary recording, is performed on the recording layer 15 using two different types of dots, the discolored portions 19 and the pits 20, in accordance with the input information. Moreover, since the optical recording medium used in the present invention has high sensitivity for both color change recording and pit recording, such ternary recording can be performed at high speed. Above, we have explained the case where an optical recording medium having a single-layer mixed recording layer is also used.
When a two-layer separation system as shown in FIG. 2 is used, the image points 18-1 and 18-2 are formed on the layer 15-2 containing the AZ compound, as shown in FIG. 2a. When the lasers 17-1, 17-2 are irradiated in this way, the image forming points 18-1, 18-2 according to the recorded information are
The AZ compound generates heat according to the exposure amounts Q ₁ and Q ₂ , and dots 19 consisting of discolored portions or pits 20 consisting of concave portions are formed as shown in FIG. 2b. The two types of dots recorded in the above manner are
Both can be read at once or just one, if desired. In the above example, a circular disk (optical disk) was used as the optical recording medium, but of course, depending on the type of substrate that supports the recording layer containing the DA compound and AZ compound, optical tape, optical It can also be used as a card, etc. [Example] In order to explain the present invention more specifically, Examples are given below. In addition, the fifth step in monomolecular film creation is
The apparatus shown in the figure was used. Example 1 1 part by weight of a diacetylene derivative compound represented by _C12H25 - _C≡C -C≡C- _C8H16 - _COOH and 1 part by weight of an azulenium salt compound represented by the above dye No. 1. A solution dissolved in chloroform at a concentration of 3 x 10 ^-3 mol/1 was developed on a water bath with a pH of 6.5 and a cadmium chloride concentration of 1/10 mol/1. After removing the solvent chloroform, while keeping the surface pressure constant, the glass substrate, which has been thoroughly washed and has a hydrophilic surface, was gently raised and lowered in a direction across the water surface at a vertical speed of 1.0 cm/min. DA compounds and AZ
A mixed monomolecular film with a compound was transferred onto a substrate, and a recording medium was prepared in which a mixed monomolecular film and a mixed monomolecular cumulative film of 21 layers, 41 layers, and 81 layers were formed on the substrate. Each of the recording media thus obtained was first uniformly and sufficiently irradiated with ultraviolet rays with a wavelength of 254 nm.
The recording layer is a blue film. Next, we applied a laser beam of 830nm that can change the laser output to the recording medium that has this blue recording layer.
The optical recording of the present invention was carried out by irradiating a semiconductor laser with a wavelength of (maximum output: 10 mW, laser beam diameter: 1 μm, irradiation time: 200 ns/1 bit) according to the input information. Incidentally, when the pit recording command was issued, the laser output was set to 8 mW, and when the color change recording command was issued, the laser output was set to 4 mW. Table 1 shows the evaluation of the recording results. The evaluation is a comprehensive evaluation of the sensitivity, resolution, and contrast ratio (sharpness) between recorded and unrecorded areas for both pit and discoloration recording. Items that could not be completed or were defective were marked as ×. Example 2 A recording medium was obtained in the same manner as in Example 1, except that the amount of the diacetylene derivative compound was 5 parts by weight and the amount of the azulenium salt compound was 1 part by weight. Recording was performed on this and evaluated. did. The recording results are shown in Table 1. Example 3 Instead of _the diacetylene derivative compound represented by _C12H25 -C≡C-C≡C- _{C8H16 -} COOH,
A recording medium was obtained in the same manner as in Example 1, except that the compound represented by C ₈ H ₁₇ -C≡C-C≡C-C ₂ H ₄ -COOH was used, and optical recording was performed on it. , and evaluated the recorded results. The results are shown in Table 1. Example 4 A recording medium was obtained in the same manner as in Example 1, 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 5 An azulenium salt compound represented by dye No. 1 was dissolved in 10 parts by weight of dichloroethylene to prepare a coating solution. Next, a glass disk substrate (thickness 1.5 mm,
200mm in diameter) on a spinner coating machine, and after dropping a small amount of the coating liquid onto the center of the disk substrate,
Coating was performed by rotating a spinner at a predetermined number of rotations for a predetermined period of time, and the coating solution was dried at room temperature, and the coating solution was applied onto a substrate to form a layer containing an azulenium salt compound with a film thickness of 200 Å. After forming the layer containing the azulenium salt compound in this way, _{C12H25 - C≡C} -C≡C- _C8H16
A solution of a diacetylene derivative compound represented by -COOH dissolved in chloroform at a concentration of 3 x 10 ^-3 mol/1 was developed on a water tank with a pH of 6.5 and a cadmium chloride concentration of 1 x 10 ^-3 mol/1. . After removing the solvent chloroform, the glass substrate with the layer containing the azulenium salt compound was moved at a vertical speed of 1.0 in the direction across the water surface while keeping the surface pressure constant.
The monomolecular film of the DA compound was transferred onto the surface of the layer containing the azulenium salt compound by gently moving it up and down at a rate of cm/min, thereby creating a recording medium containing the monomolecular cumulative films of 41 and 81 layers. First, 254 nm was applied to the recording medium obtained in this way.
The recording layer was uniformly and sufficiently irradiated with ultraviolet rays to form a blue film. Next, optical recording was performed on the recording medium having this blue-colored recording layer in the same manner as in Example 1, and the results were evaluated. The results are shown in Table 1. Example 6 Instead of _the diacetylene derivative compound represented by _C12H25 -C≡C-C≡C- _{C8H16 -} COOH,
A recording medium was obtained in the same manner as in Example 5, except that the compound represented by C ₈ H ₁₇ -C≡C-C≡C-C ₂ H ₄ -COOH was used, and optical recording was performed on it. , and evaluated the recorded results. The results are shown in Table 1. Example 7 A recording medium was obtained in the same manner as in Example 5 except that an azulenium salt compound represented by dye No. 13 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.

[Table] *2: Pit recording [Effects of the invention] The effects of the optical recording method of the present invention are listed below. (1) Since the recording layer contains a combination of an azulenium salt compound and a polydiacetylene derivative compound, it is possible to perform color change recording and pit recording on one recording medium as desired using a small and lightweight semiconductor laser. can. That is, high-density recording by ternary recording is possible with one recording medium. Moreover, the recording layer has high sensitivity in both color change recording and pit recording, and high-speed recording is possible. (2) Since the recording layer is composed of at least a diacetylene derivative compound as a monomolecular film or a cumulative film thereof, the constituent components of the recording layer have a high density and a high degree of order, and the recording layer is homogeneous. In addition, since it is formed with good surface properties, it is possible to perform optical recording with excellent stability and high quality. (3) Optical recording using an inexpensive recording medium having a highly homogeneous, large-area recording layer becomes possible.

[Brief explanation of drawings]

1a, b and 2 a, b are schematic cross-sectional views illustrating the optical recording process of the present invention, and FIGS.
b is a schematic diagram showing an embodiment of the configuration (two-layer separation system) of an optical recording medium used in the method of the present invention;
FIGS. 4a and 4b are schematic diagrams showing an embodiment of the structure of the optical recording medium (single-layer mixed system) used in the method of the present invention, and FIGS. FIG. 11: Substrate, 15: Recording layer, 15-1: Layer containing DA compound, 15-2, 21: Layer containing AZ compound, 16-1: DA compound, 16-2: AZ compound, 17-1: Exposure Laser beam of quantity Q, 1
7-2: Laser beam with exposure amount Q, 18-1,
2: Exposure area (imaging area), 19: Discoloration area, 20: Pit.

Claims (1)

[Scope of Claims] 1. A recording layer comprising a monomolecular film of a diacetylene derivative compound having at least a hydrophilic site and a hydrophobic site or a cumulative film thereof, and an azulenium salt compound having a skeleton represented by the following general formula (). The optical recording medium comprising the above is irradiated with ultraviolet rays, and then irradiated with light whose exposure amount is controlled according to the recorded information.The light with an exposure amount of Q ₁ causes discoloration, and the light with an exposure amount of Q ₂ causes recesses. The process of forming a pit consisting of (however, Q ₁
<Q ₂ ). (In the formula, R ₁ to _{R 7} represent a hydrogen atom, a halogen atom, or a monovalent organic residue.)