JPS62140886A - Optical recording medium - Google Patents

Abstract

PURPOSE:To provide a recording medium capable of being used for optical recording or thermal recording according to the functions of a diacetylene derivative compound (DA) and a compound having a skeleton of a specified general formula (AZ), by constituting a recording layer of a mixed monomolecular film of the DA compound and the AZ compound or a built-up film thereof. CONSTITUTION:A recording layer 2 comprising a mixed monomolecular film of a DA compound 3 and an AZ compound 4 is provided (a) on a base 1, or a built-up film (b) of the mixed monomolecular film is provided on the base 1. The AZ compound has a skeleton of general formula (1), wherein l is an integer of 6-20, and generates heat when irradiated with IR rays of a wavelength of not less than 750nm. When the entire body of the recording layer 2 is irradiated with UV rays, the DA compound 3 is polymerized to be a polydiacetylene derivative compound (PDA), whereby the layer 2 is changed to be a blue film. Next, when predetermined parts of the layer 2 are irradiated with laser beams of a wavelength of 800-850nm blinking according to an information signal, the PDA does not absorb the laser beams, while the AZ compound salt 4 absorbs the beams to generate heat, which is transferred to the adjacent PDA to turn the latter red. Accordingly, a record can be obtained through a color change at recording parts according to the input information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium, and particularly to an optical recording medium suitable for optical writing using an infrared laser.

[Conventional technology]

Recently, optical discs 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 elements have been studied for this optical disk, 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 elements, and a recording technique for use as a laser recording element was disclosed in Japanese Patent Laid-Open No. 147807/1983, focusing on the thermochromic properties of these compounds. ing. but,
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 was confirmed that laser recording could not be performed when a low-output semiconductor laser (wavelength: 800 to 850 nm) was used. However, for practical recording media such as optical discs, it is required that optical writing be possible using a small, low-output semiconductor laser.

Furthermore, the recording layer of the recording medium disclosed in JP-A-56-147807 is composed of microcrystals of diacetylene derivative compounds dispersed in a binder, and the orientation of these compounds within the recording layer is random. As a result, light absorption and reflectance vary depending on location, and the degree of chemical reaction varies, making it not necessarily suitable for high-density recording.

[Problem that the invention seeks to solve]

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide an optical recording medium that can be optically written with a small and lightweight semiconductor laser.

Another object of the present invention is to provide an optical recording medium capable of high-density, high-sensitivity, and high-speed recording.

Still another object of the present invention is to provide an optical recording medium with excellent stability and high quality.

Another object of the present invention is to provide an optical recording medium having a recording layer that has excellent film-forming properties and does not easily peel or peel off.

[Means for solving problems]

The above object is achieved by the present invention as follows.

That is, the present invention is an optical recording medium characterized by having a mixed monomolecular film of a diacetylene derivative compound and a compound having a skeleton represented by the following general formula (1) or a cumulative film thereof.

[Effect]

Diacetylene derivative compound (hereinafter referred to as DA) used in the present invention
compound) has both a hydrophilic site and a hydrophobic site, and between the CmiC-CmiC functional groups, 1.4-
A compound capable of an addition polymerization reaction, typically represented by the following general formula (%) (wherein, X is a hydrophilic group forming a hydrophilic moiety,
(m and n represent integers) Examples include compounds represented by the following formula.

Examples of the hydrophilic group X in the above DA compound include a carboxyl group, an amide group, a hydroxy group, a nitrile group,
Examples include 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 (CH2)m forming the aqueous moiety is preferably a long chain alkyl group having 10 to 3 carbon atoms, and m+n is 1 to 30 carbon atoms.
An integer of is preferred.

On the other hand, it is a compound that has a surface absorption spectrum peak in the general formula (1) used in the present invention and generates heat by infrared light of this wavelength.

The AZ compounds can be roughly classified into the following three types.

n-CIH2i+1 In the above formulas (2) to (4), A represents a divalent organic residue bonded by a divalent combination, such as n-C H2+1 and derivatives thereof. I can do it.

Ze represents an anionic residue, for example, berchlorate 1. These include fluoroporate, p-toluenesulfonate, perfiodide, chloride, bromide, or iodide.

A sentence is an integer that satisfies the relational expression 6≦intersection≦20.

Note that the hydrogen atoms in the condensation terms of the compounds represented by general formulas (2) to (4) may be substituted with other substituents, such as halogen atoms or monovalent organic residues. can be mentioned.

Monovalent organic residues can be selected from a wide variety of groups, but in particular alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, etc.), alkoxy groups (methoxy, nidoxy, etc.), Examples include a substituted or unsubstituted heptaryl group (phenyl, tolyl, xylyl, etc.), a substituted or unsubstituted amino group (amino, dimethylamino, etc.), a nitro group, a hydroxy group, a cyan group, and the like.

Examples of the compounds represented by the general formulas (2) to (4) are shown below.

A typical configuration of the optical recording medium of the present invention is shown in FIGS. 1 and 2.
An example is shown in the figure. In the example shown in FIG. 1, a recording layer 2 consisting of a mixed monomolecular film of the DA compound 3 and the AZ compound 4 is formed on a substrate 1, and in FIG. It is something. Note that a protective layer (not shown) may be provided on the recording layer 2 if necessary.

As the substrate 1 of the optical recording medium of the present invention, various supporting materials such as glass, a plastic plate such as acrylic resin, a plastic film such as polyester, paper, and metal can be used. When recording, a device that transmits recording radiation of a specific foot length is used.

Such a monomolecular film or a monomolecular near projection method (hereinafter abbreviated as LB method) is used on the substrate 1. 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 (balance of amphiphilicity) is maintained appropriately, this molecule is placed on the water surface with the parent group below. This is a method of creating a monomolecular film or a film made up of monomolecular layers by utilizing the fact that the monomolecular layer is oriented. A monolayer on the water surface has the characteristics of a two-dimensional system.

When the molecules are sparsely spread, the area per molecule is A
The two-dimensional ideal gas equation, nA=kT, holds true between and the surface pressure (2), resulting in a "gas film", where k is Portzmann's constant and T is the absolute temperature. If A is made sufficiently small, the intermolecular interaction becomes strong, 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.

In addition, 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.

Using this method, a mixed monomolecular film or a mixed monomolecular cumulative film of a DA compound and an AZ compound salt constituting the recording layer of the present invention is produced, for example, as follows. First, a DA compound and an AZ compound salt are dissolved in a solvent such as chloroform, and this is developed on an aqueous phase to form a developed layer in which these compounds are developed into a film. dividers (or floats) to allow the water to spread freely and prevent it from spreading too much.
is provided to limit the area of the developed layer and control the state of aggregation of these compounds, thereby obtaining a surface pressure (1) proportional to the state of aggregation.

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 n suitable for producing a cumulative film. By gently moving the clean substrate vertically up and down while maintaining this surface pressure, a monomolecular film of the DA compound and the AZ compound salt is transferred onto the substrate. A mixed monomolecular layer film is produced in this manner, and a mixed monomolecular layer cumulative film having a desired degree of accumulation is formed by repeating the above-mentioned operations.

In addition to the above-mentioned vertical dipping method, methods such as a horizontal deposition method and a rotating cylinder method can be used to transfer the monomolecular film onto a substrate. The horizontal deposition method is a method in which the substrate is brought into horizontal contact with the water surface 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 a substrate with a lignophilic surface is lifted out of water in a direction transverse to the water surface, a monomolecular layer of the DA compound and AZ compound with the hydrophilic groups facing the substrate is formed on the substrate. It is formed. As the substrate is moved up and down, one layer of mixed monomolecular film is deposited with each step. Since the direction of the film-forming molecules is reversed between the pulling step and the dipping step, according to this method, a Y-shaped film is formed between each layer 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 layer with the hydrophobic groups of the DA compound and the AZ compound facing the substrate is formed on the substrate. In this method, there is no change in the orientation of the molecules of the DA and AZ compounds even if they are accumulated, and an X-type film is formed in which the hydrophobic groups face the substrate in all layers. A cumulative film in which the wood base faces the substrate side is called a type 2 film.

The rotating cylinder method is a method in which a cylindrical substrate is rotated on the water surface to transfer a monomolecular layer onto the surface of the substrate. The method of transferring the monomolecular layer onto the substrate is not limited to these methods, and when using a large-area substrate, a method of extruding the substrate from a substrate roll into an aqueous phase 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.

Details of these monomolecular film transfer operations are already known and are described, for example, in "New Experimental Chemistry Course 18 Interfaces and Colloids", pages 498-507, published by Maruzen.

Normally, when forming a mixed monomolecular film or a cumulative film of two or more compounds, it is sufficient that at least one of the compounds has both a hydrophilic site and a hydrophobic site; not all compounds are necessarily hydrophilic. Although it is not required to have both a hydrophilic site and a hydrophobic site, according to the research of the present inventors, not only DA compounds but also AZ compounds have a hydrophilic site and a hydrophobic site ( It has been found that by maintaining the balance of amphiphilic properties, the film forming properties of a mixed monomolecular film or a cumulative film thereof are particularly excellent.

That is, in the process of forming a monomolecular film or a cumulative film thereof, it has become possible to form a film with almost no peeling or flaking from the substrate, and it has become possible to form a film with high efficiency.

The mixing ratio of DA compound and AZ compound is 20/1 to 1.
/20 is preferred, and suitably 1°/1 to 1/10.

In this way, the mixed monomolecular film and its cumulative layer formed on the substrate have a high density and a high degree of order, so the variation in light absorption depending on the location is extremely small, and the AZ compound itself Since the mixed monomolecular film and its cumulative film have excellent film-forming properties, there is almost no peeling or flaking of the film.

Therefore, by configuring the recording layer with such a film, it has a recording function of high density, high resolution, and high precision capable of optical recording and thermal recording, depending on the functions of the DA compound and the AZ compound salt. A recording medium is obtained.

The optical recording medium of the present invention allows various types of optical recording to be performed; however, by applying light or heat, the absorption wavelength of the recording layer changes and the apparent color changes. The recording mechanism using a semiconductor laser will be briefly explained below.

The DA 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 irradiation with ultraviolet rays, and not by the application of other physical energy such as heat. As a result of this polymerization, the recording layer has a maximum absorption wavelength of 620 to 660 nm and changes to a blue color. do. The change in hue due to this polymerization is an irreversible change, and once the recording layer has changed to blue, it will not return to a colorless transparent film.Also, if the polydiacetylene derivative compound that has changed to blue is heated to about 50°C or higher, has a maximum absorption wavelength at about 540 nm, and turns into a red film.

This change is also an irreversible change.

Therefore, optical recording using the recording medium of the present invention is carried out by the following mechanism.

First, when the entire recording layer of the optical recording medium of the present invention is irradiated with ultraviolet rays, the DA compound 3 in the recording layer polymerizes and changes into a polydiacetylene derivative compound, thereby changing the recording layer 2 into a blue film.

Next, when a predetermined position of this recording medium is irradiated with a semiconductor laser beam with a wavelength of 800 nm and 850 nm that blinks in response to an information signal, the polydiacetylene derivative compound does not absorb this laser beam, but the AZ compound salt 4 in the recording layer It absorbs this laser beam and generates heat. The heat generated by the AZ compound salt 4 is transmitted to the adjacent polydiacetylene derivative compound, and the color changes to red. In this way, optical recording is performed by changing the color of the recording area on the recording layer in accordance with the input information.

〔Example〕

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

Example 1 The apparatus shown in Fig. 2 was used to form a monomolecular film.
C12H25-C=C-C=C-C9H1B-COOH
A solution prepared by dissolving 1 part by weight of a diacetylene derivative compound represented by and 1 part by weight of an AZ compound salt represented by the above compound NO65 in chloroform at a concentration of I x 10-3 mol/l was prepared at a pH of 6.5. It was developed on an aqueous phase with a cadmium chloride concentration of I×10 −3 mol/U.

After removing the solvent chloroform, the glass substrate, which has been thoroughly cleaned and has a hydrophilic surface, was moved at a vertical speed of 1.0 cm/cm in a direction across the water surface while keeping the surface pressure constant.
The mixed monomolecular film of the DA compound and the AZ compound salt was transferred onto the substrate by gently moving it up and down for several minutes. An optical recording medium was created.

Example 2 An optical recording medium was prepared in the same manner as in Example 1, except that the diacetylene derivative compound was used in an amount of 2 parts by weight per 1 part by weight of the AZ compound salt.

Example 3 An optical recording medium was prepared in the same manner as in Example 1, except that the diacetylene derivative compound was used in an amount of 10 parts by weight per 1 part by weight of the AZ compound salt.

Example 4 An optical recording medium was prepared in the same manner as in Example 1, except that 15 parts by weight of the diacetylene derivative compound was added to 1 part by weight of the AZ compound salt.

Comparative Example 1 An optical recording medium was produced in the same manner as in Example 1, except that only the diacetylene derivative compound was used without using the AZ compound salt.

Comparative Example 2 A film with a thickness of 1500 mm was formed on a glass substrate by sputtering.
A radiation absorbing layer of human Gd-Tb-Fe was provided. Using this substrate, an optical recording medium was prepared in which a monomolecular film or a monomolecular cumulative film of a diacetylene derivative compound was formed on the radiation absorbing layer in the same manner as in Comparative Example 1.

Comparative Example 3 An optical recording medium was prepared in exactly the same manner as in Example 1, except that the AZ compound represented by the following formula was used.

Example 5 C12H25-C= C-C= C-C8H16-C0
Instead of the diacetylene derivative compound represented by 0H,
An optical recording medium was prepared in the same manner as in Example 1 except that a diacetylene derivative compound represented by CBHt7-C=C-C5C-C2H4-COOH was used.

Examples 6 to 8 Optical recording media were prepared in the same manner as in Example 5, except that AZ compound salts represented by compounds No. 6.12 and 15 were used in place of the AZ compound salt represented by compound N015. It was created.

Comparative Example 4 Comparative Example 3 except that a compound represented by the following formula was used as the AZ compound.

An optical recording medium was prepared in exactly the same manner as in Comparative Example 3.

The optical recording media prepared in Recording Test Examples 1 to 8 and Comparative Examples 1 to 4 were uniformly and sufficiently irradiated with 254 nm ultraviolet rays to form a blue film in the recording layer. Next, the output is 3 mW and the wavelength is 830 nm.
A semiconductor laser beam having a beam diameter of 1 gm was irradiated onto a predetermined position on the surface of each optical recording medium according to the input information (irradiation time: 200 ns/l bit) to form a red recorded image on the blue recording layer.

The evaluation of the recording results is shown in Table 1. Evaluation was made based on the quality of recording sensitivity, image resolution, and image density, with particularly good results being rated 0, good results being 0, and cases in which recording was not possible or poor.

In addition, film forming properties were evaluated in terms of film forming rate and film surface unevenness.

The film formation rate was calculated by performing an operation of accumulating a monomolecular film on a circular glass substrate of 20 mm diameter in 7 atmospheres on 50 glass substrates, and peeling off the monomolecular film during the accumulation process among the 50 operations. , based on the percentage of times the film was successfully transferred onto the substrate without peeling.

50% or less × 50-80% 0 80% or more ■ Surface unevenness of the film can be checked visually and with an optical microscope (500x magnification)
The state of the film surface was observed, and a film with a uniform surface was marked as 0, a film with partial peeling was marked as Δ, and a film with extensive peeling and clear irregularities on the surface was marked as ×.

Table 1 Table 1 (continued) 〔Effect of the invention〕 The effects of the recording medium of the present invention are listed below.

(1) Since the recording layer is formed of a mixed monomolecular film of DA compound and AZ compound salt or a cumulative film thereof, it has high density and a high degree of order, thus enabling high density and homogeneous recording. It is.

(2) A highly homogeneous recording layer can be manufactured at low cost even on a large-area support.

(3) Since the recording layer contains an AZ compound salt that absorbs infrared rays in the wavelength range of 800 to 850 nm and generates heat,
Recording can be performed using a small and lightweight semiconductor laser that emits infrared rays in the wavelength range of 0 to 850 nm.

(4) Since it is possible to record using changes in the hue of the recording layer due to light irradiation, high-speed, high-sensitivity, and high-density optical recording can be performed.

(5) Since both DA and AZ compounds have excellent film-forming properties,

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are schematic cross-sectional views illustrating the structure of the optical recording medium of the present invention, and FIG. 2(a) is a schematic cross-sectional view illustrating the structure of the optical recording medium of the present invention. (b) is a schematic diagram showing an example of a film forming apparatus used in the present invention. 1- Substrate 2- Recording layer

Claims (1)

[Scope of Claim] An optical recording medium characterized by having a mixed monomolecular film of a diacetylene derivative compound and a compound having a skeleton represented by the following general formula (1) or a cumulative film thereof. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) However, in the formula, l is an integer that satisfies the relational expression 6≦l≦20.