JPS6137481A - Optical recording element - Google Patents

Abstract

PURPOSE:To obtain highly reliable and densely recordable optical recording elements by laminating a layer A of color-forming compound and a layer B of assistant color-forming compound with a light-absorbing layer and making up the layer B of either a monomolecular film or an accumulated film of the former. CONSTITUTION:A layer-A 2 of color-forming compound and a layer-B 4 of assistant color-forming compound are laminated with a light-absorbing layer 3 provided on the layer-B 4. The layer-B 4 is a laminate of a monomolecular film or an accumulated film of the former, and the layer-A 2 and the light-absorbing layer 3 are laminates of laminated films. The light-absorbing layer 3 is supported on a substrate 1 and the substrate, light-absorbing layer, layer B and layer A are laminated in that order. Consequently, the titled optical recording element has higher packing density than the conventional element. The former also has a higher signal/noise ratio and subsequently a higher recording reliability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical recording element using an organic material, and in particular to a highly reliable and high-density recording device using a highly molecularly oriented monolayer thin film. The present invention relates to a possible optical recording element.

[Background Art] Recently, optical disks have been attracting attention as a central recording device for office automation (OA). The reason for this is that a single optical disc can record (or store) a large amount of documents, literature, etc. Therefore, introducing an information storage device using this optical disc will revolutionize the organization and management of documents and literature in offices. It is expected that it will bring In addition, organic materials, which have characteristics such as low cost, ease of manufacture, and high-density recording properties, are attracting attention as recording materials for optical discs.

Among the conventional techniques using such organic recording materials.

In particular, a two-component optical recording element that utilizes a color-forming reaction caused by contact between a color former and a periodizing agent has been reported (Nikkei Sangyo Shimbun
1981 10JJ 18B).

An example of the conventional optical recording element will be explained based on the drawings. As shown in FIG. It consists of a laminated structure.

The coloring agent (leuco body) and the coloring agent are colorless or light-colored when each exists alone.

When recording on the recording element, a laser beam 8 is irradiated onto a desired position of the light absorption layer 6 as shown in FIG. 2(b).
The portion of the light-absorbing layer that is irradiated with the laser beam absorbs the laser beam, melts, and rips, leaving a small hole.

As a result, as shown in FIG. 2(C), the coloring agent and the time-setting agent, which were separated by the light absorption layer 6, mix through the small holes and develop a color. Information is recorded or stored in the form of coloring points 9, and reading is performed by scanning the recording element with another light source and detecting changes in reflection, transmittance, etc. due to the coloring points.

[Problems to be Solved by the Invention] In the above-mentioned optical recording element, in order to achieve high recording Ω density, it is desirable that the light absorption layer 6 be as thin as possible, flat, and without uneven IQ thickness. However, in conventional optical recording elements, the light absorption layer is coated on the substrate by, for example, a vacuum evaporation method or a spin coating method. Since the two components, the coloring agent and the preservative, come into contact with each other at these pinholes and develop color, there is a drawback of lack of reliability. Furthermore, since the molecular distribution and orientation within the film of each layer formed by the above-mentioned conventional coating method is random, light scattering occurs within the film with light irradiation, and when viewed microscopically, each light irradiation The degree of chemical reaction that occurs differs each time. Furthermore, the above-mentioned coating method has drawbacks such as unevenness in film thickness and uneven recording quality when the substrate of an optical disk has a large area.

Therefore, as an optical recording element, it is desirable that the molecular distribution and orientation within the film be uniform, that there are no pinholes, and that the film thickness is uniform, and that the film thickness be as thin as possible to achieve high recording density and high reliability. The present invention has been made in view of these demands, and an object of the present invention is to provide an optical recording element capable of highly reliable and high-speed recording. Another object of the present invention is to provide an optical recording element that is easy to manufacture and inexpensive.A further object of the present invention is to provide an optical recording element with a large area.

[Means for Solving the Problems] and [Operation] That is, the present invention consists of a layer A consisting of a color-forming compound that is usually colorless or light-colored, and a layer B consisting of an auxochrome compound that develops a color when it comes into contact with the color-forming compound. and (a) layer B is a layer consisting of a monomolecular film of an auxochrome compound or a cumulative film thereof. It is a recording element.

The present invention will be explained in detail below.

The optical recording element according to the present invention has a structure in which a layer A consisting of a usually colorless or light-colored color-forming compound, an auxochromic compound that develops color when in contact with the color-forming compound are laminated, and a light-absorbing layer is further provided. The city is requested to use a combination of substances that develop color when they come into contact with and mix with each other in the A layer and the B layer. Specific examples of colorless to light-colored color-forming compounds and auxochromic compounds that develop color when they come into contact with the color-forming compound in layer B are as follows: (a) An acidic substance (layer B) that develops color when it comes into contact with the acidic substance. Leuco form of dye (dye precursor) (layer A) (b) Oxidizing agent (layer B) and leuco form of dye that develops color by contacting the oxidizing agent (layer A) (c) Reducing agent (layer B) ) and leucoization of the dye that develops color upon contact with the binary agent (layer A) (d) reducing agent (layer B) and stearic acid f
J, oxidizing agent that develops color when reduced like 2 iron (A layer)
(e) An oxidizing agent (layer B) and a reducing agent (layer A) that develops color when oxidized, such as gallic acid.

To give a more detailed example of the case (a) above, the acidic substances in the B layer that react with the leuco form of the dye to develop color include aromatic sulfonic acid compounds such as benzenesulfonic acid, benzene, aromatic acid, etc. aromatic carboxylic acids, valmitic acid LL+5H3/eooH), stearic acid (c+7H3
5coon), araxic acid (CnH3yCOOH)
Examples thereof include higher fatty acid carboxylic acids such as pt-butylphenol, α-naphthol, β-naphthol, phenolphthalein, bisphenol A, 4-hydroxydiphenoxide, and 4-hydroxyacetophenone.

Next, examples of the leuco dyes in the A layer that react with the acidic substance include triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran. The details of the compounds are shown in Table 1.

In the present invention, since layer B is formed from a medium molecular film or a layer consisting of a cumulative layer thereof, the auxochrome compound has a parent group, a hydrophobic group, or both groups at appropriate sites within the molecule. It is necessary to use the introduced derivative.

Any commonly used hydrophobic groups can be used as the hydrophobic groups, but particularly preferred hydrophobic groups include long-chain alkyl groups having 5 to 30 carbon atoms, hydrophilic groups, For example, carboxyl groups and metal salts thereof (eg cadmium salts) are preferable.

On the other hand, the A layer may be any film formed by a conventional coating method, and among these, a layer made of a deposited film such as a vapor deposited film, a coating film, a immersion film, or a laminated film is preferable.

Note that the thickness of the A layer and Bfi is preferably in the range of 200 to 1oIL, preferably in the range of 1,000A to 1-.

Next, the light-absorbing material used in the formation of the light-absorbing layer in the present invention may be any light-absorbing dye that absorbs infrared rays, such as a melting light-absorbing dye that melts by absorbing infrared rays, or Sublimable light-absorbing dyes that absorb infrared rays and sublimate can also be used, but non-melting dyes and non-sublimating dyes are particularly preferred.

Examples of such light-absorbing dyes include metal phthalocyanines such as copper phthalocyanine and vanadium phthalocyanine;
There are xanthine dyes such as fluorescein.

The light absorbing layer may be any film formed by conventional coating methods, such as vapor deposited film, coating film, immersion film, etc. tll! 2. A layer consisting of a deposited film such as a laminate is preferred.

What is the thickness of the light absorption layer? A range of 30 to 2,000 people is desirable, preferably a range of 140A to 400 people.

In addition, the materials used for the substrate in the present invention include:
Semiconductor materials such as silicon, metal materials such as aluminum, preferably tempered glass, more preferably acrylic (PMMA),
polycarbonate (pc), polypropylene, poly I
! Preferred are plastic materials such as polyvinyl chloride (PVG) and polystyrene, and ceramic materials.

One feature of the optical recording element according to the present invention is that the B layer is composed of a single molecule 119 of an auxochromic compound or a cumulative number thereof.

As a method for producing a monomolecular film or a cumulative film thereof having such high orderliness and orientation of molecules, for example, 1. La
The Langmuir-Prodgett method (La method) developed by Ngmuir et al. is used. The Langmuir-Prodgett method is based on the Langmuir-Prodgett method. For example, when a molecule has a parent tree group and a hydrophobic group in its molecule, and the balance between the two (balance of amphiphilicity) is maintained appropriately, the molecule will react to the parent tree on the water surface. This is a method of creating a monomolecular film or a monomolecular cumulative film by using the fact that the monomolecular layer is formed with the group facing downward. When the monomolecular layer on the water surface is sparsely dispersed with 0 molecules that have the characteristics of a two-dimensional system, the two-dimensional ideal gas equation between the surface vIA and the surface pressure ■ per molecule, nA = kT. holds true, resulting in a “°gas film”, where is Portzmann's constant and T is absolute 9 degrees. If A is made sufficiently small, the intermolecular interaction will become stronger, resulting in a two-dimensional solid condensed film (or solid film). Condensed films can be made of various materials and shapes, such as plastic substrates, glass: J, Ti plates, etc. It can be transferred layer by layer to the surface of the carrier.

Next, the method for forming a monomolecular film or a cumulative film of organic molecules having both a parent group and a hydrophobic group, which is an auxochrome compound used in the present invention, will be described in detail.

First, the organic molecule is dissolved in a volatile solvent such as benzene or chloro-based lumen, and the organic molecule is dissolved in a cylinder or the like onto the aqueous phase 11 in the water tank 10 of the heavy molecule accumulation 11 forming apparatus schematically shown in FIG. Let it develop.

As the solvent evaporates, the organic molecules develop on the water phase 11 with the parent tree groups 12 facing the water phase and the hydrophobic groups 13 facing the gas phase.

Next, to prevent the precipitates (organic molecules) from freely diffusing and spreading over the aqueous phase 11, a partition plate (or float) 14 is provided to limit the spread area and control the aggregation state of the substances. , obtain a surface pressure ■ proportional to its collective state. By moving the partition plate 14, 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 the surface pressure (2) suitable for producing a cumulative film. By gently vertically moving the clean substrate 14 up and down while maintaining this surface pressure, the single molecules 1121B are transferred onto the substrate. Monomolecular film 1B is manufactured as described above, but monomolecular layer formation condition 1
In step 7, by repeating the above operations, a desired cumulative number of monomolecular layers are formed.

For example, when the substrate 15 whose surface is woody is pulled out of water in a direction across the water surface, the woody groups of the organic molecules are removed from the substrate 15.
A side-facing monolayer 18 is formed on the substrate 15 . When the substrate 15 is moved up and down as described above, monomolecular Hte is piled up one by one in each process.The direction of the film-forming molecules is reversed in the pulling process and the dipping process, so according to this method, the distance between each layer is A so-called Y-type film is formed in which the parent wood groups of the organic molecules and the parent wood groups and the hydrophobic groups of the organic molecules face each other (Fig. 4(a)).

The Y-type film is strong because the hydrophilic groups and hydrophobic groups of the organic molecules face each other.

In contrast, only when lowering the substrate 15 into the water,
There is also a method of transferring the organic molecules onto the substrate surface.

In this method, there is no change in the direction of the film-forming molecules even if they are accumulated, and an X-shaped film is formed in which the hydrophobic groups face the substrate 15 in all layers (Fig. 4(b)). A cumulative film in which parent wood groups in all layers face the substrate 15 side is called an X-type film (FIG. 4(C)).

The X-type film is obtained by transferring organic molecules to the substrate surface only when the substrate 15 is lifted out of the water.

The monomolecular film and monomolecular layer cumulative film formed on the substrate by the above method have high density and a high degree of order and orientation, and by configuring the recording layer with these films, photothermal Accordingly, it is possible to obtain a recording element having a high-density and high-resolution recording function capable of performing digital recording. Further, as can be seen from the principles thereof, these film forming methods are very simple methods, and a recording element having the above-mentioned excellent recording function can be provided at low cost.

The substrate on which the monomolecular Q or the monomolecular cumulative film in the present invention is formed as described above is not particularly limited, but if a surfactant is attached to the surface of the substrate, when the monomolecular layer is transferred from the water surface, Since the molecular film is disturbed and a good monomolecular film or monomolecular layer stack cannot be formed, it is necessary to use a substrate with a clean surface.

The monomolecular film or monomolecular layer cumulative film on the substrate is fixed strongly enough that it hardly peels off or peels off from the lino board. Alternatively, an adhesive layer may be provided between the Cli molecular layer stacked films. Furthermore, the adhesion force can be strengthened by selecting the monomolecular layer formation conditions, such as the hydrogen ion concentration of the aqueous phase, the ion species, the water temperature, the rate of raising and lowering the carrier, or the surface pressure.

Next, the method for forming the deposited film of layer A or light absorption layer is to grind and mix a water-friendly product obtained by adding a binder and water to the color-forming compound or light-absorbing substance using a ball mill, etc. This is done by applying it on top using the conventional method.

The binder used in the present invention includes gelatin,
Natural polymers such as starch, cellulose nitrate, cellulose derivatives such as carboxymethyl cellulose, chlorinated rubber,
Semi-synthetic polymers such as natural rubber plastics such as cyclized rubber, polyisobutylene, polystyrene, terpene resins,
Polyacrylic acid, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, polyacrylamide, polyvinyl acetate, polyvinyl alcohol, polyvinylpyrrolidone, polyacetal resin, polyvinyl chloride, polyvinylpyridine, polyvinylcarbazole,
Polymerizable synthetic polymers such as polybutadiene, polystyrene-butadiene, butyl rubber, polyoxymethylene, polyethyleneimine, polyethyleneimine hydrochloride, poly(2-acryloxyethyldimethylsulfonium chloride), phenolic resin, amine resin, toluene resin, alkynd Condensation polymerization type synthetic polymers such as resins, unsaturated polyester resins, allyl resins, polycarbonates, polyamide resins, polyether resins, silicone resins, furan resins, thiokol rubber, etc., addition polymerization type resins such as polyurethane, polyurea, epoxy resins, etc. can be mentioned.

An example of the structure of an optical recording element related to wood oxide 1 produced by the method described above is shown in FIG. The 8 layers 4 are laminated, and the light absorption layer 3 is provided roughly on the B layer 4, and the 8 layers 4 are a monomolecular film or a cumulative film thereof, and the A layer 2
The light-absorbing layer 3 is a carcass consisting of a deposit +1i, and the light-absorbing layer 3 is supported on a substrate l, and is laminated in the order of substrate/light-absorbing layer/B layer/A layer. In this case, the A layer 2 and the 8 layer 4 may be reversed and laminated in the order of substrate/light absorption layer/A layer/B layer.

Furthermore, to show another example, as shown in FIG. 1(b), A
Layers 2 and 8 layers 4 are laminated, a light absorption layer 3 is provided roughly on the A layer 2 to form a laminate, the 8 layers 4 are supported on a substrate l, and the substrate/B layer/A It is formed by laminating layers/light absorption layer in this order. In this case, similarly to the above, the A layer 2 and the 8-layer 4 may be reversed and laminated in the order of substrate/A layer/B layer/light absorption layer.

Furthermore, in any of the configurations shown in FIGS. 1(a) and 1(b), two of the above-mentioned laminates may be stacked and supported on the substrate.

The optical recording element according to the present invention comprises A made of a color-forming compound.
11. Although it is constructed by closely adhering the B layer made of an auxochrome compound, it has been thought that such a construction is impossible with conventional technology. However, in the present invention, since the B layer is formed of a single molecule having a high degree of order and orientation and its cumulative film, reactive sites can be linked together via non-reactive sites within the molecules. The above configuration was made possible because of the ability to separate them.

Further, since the optical recording element according to the present invention is constructed by laminating the A layer and the B layer in close contact with each other and further providing a light absorption layer on the outside, the light absorption layer is heated by infrared irradiation.
Due to the heat conduction, the color-forming compound in the A layer and the auxochrome compound in the B layer come into contact with each other under heat, and a color-forming reaction progresses, forming a color-forming point at a predetermined position so that information can be recorded.

Therefore, the optical recording element according to the present invention can be mainly used as an optical disc. An example of an information storage device having an optical pickup optical system for writing or reading information from the optical disc is fJS5.
As shown in the figure.

The information storage device is composed of a writing means consisting of a control circuit 27 and an optical pickup optical system, an optical recording element according to the present invention, and a reading means consisting of an output circuit 28 and an optical pickup optical system.

The aging process is done as follows. The control circuit 27 controls the oscillation of the semiconductor laser 2B. Therefore, the input information is converted into an optical signal by the control circuit 27 and the semiconductor laser 2G. The optical signal 29 passes through the optical pickup optical system shown in FIG. 5, forms an image on the recording layer Q of the optical disk 18 which is rotating synchronously, and is recorded in color by the coloring mechanism described above.

Reading is carried out as follows. A low-output continuous wave light emitted from the semiconductor laser 26 is used as the reading light. Since the output is low, color recording is not performed during reading. Alternatively, another visible light source may be used as the reading light source.

The reading light beam forms an image on the substrate surface of the optical disk 18 and is reflected, but since the reflectance differs between the coloring point and the non-coloring point, this reflected light is applied to the light receiving surface of the photodiode 25 through the optical pick amplifier optical system. By doing so, it is converted into an electrical signal and read out for reproduction.

In order to increase the contrast of the reproduced signal and improve the image quality, it is preferable to provide a reflective layer of metal such as aluminum on the substrate of the optical recording element.

The thickness of the metal reflective layer is preferably 1,000 to 2,000. In addition, a dielectric mirror may be used as necessary.

Furthermore, a protective layer may be provided on the surface of the outermost layer to protect the A layer, B layer, light absorption layer, etc. Materials for such a protective layer include dielectrics such as 5i07, plastic resins, and other materials. Polymerizable 1 film etc. are suitable.

[Example] Hereinafter, the present invention will be explained in more detail by showing examples. In the following, unless otherwise specified, "part" means "part by weight" and "1%" means "% by weight."

Example 1 (1) Method for forming a light-absorbing layer A glass (disc) substrate on a disk with a thickness of 10 m and a diameter of 18 hm was thoroughly cleaned, and then 7 parts of vanadium phthalocyanine, which is a light-absorbing substance, 1 part of polyvinyl alcohol and 40 parts of water are mixed as a binder, and the mixture is ground and mixed using a ball mill for several hours, and then spin-coated onto the substrate-L to form a deposited film of vanadium phthalocyanine dispersed in the binder (thickness: 0. 015 pL) were obtained.

(2) Method for Forming Layer B Next, on the light absorption layer formed on the glass substrate of each sample (y) in (1) above, an auxochrome compound was added using the monomolecular accumulator described above. Is araxic acid? A cumulative film of n molecules was formed.

The method for forming the monomolecular cumulative film of alaxic acid was performed as follows.

After submerging the substrate in water so that the substrate on which the light absorption layer was formed is perpendicular to the water surface, the concentration of alexic acid was 2X.
A chloroform solution of 10-3 mol/l was dropped onto the water surface and a monomolecular film was developed on the water surface at a surface pressure of 30
dyne/cm, and moved the substrate up and down at a speed of 2 cm/win to measure the monomolecular cumulative film (
A Y-type membrane) was prepared for each sample.

(3) Formation method of A layer Next, the B layer formed on the glass substrate of each sample in (2) above.
A deposited film of crystal violet lactone, which is a color-forming compound, was formed on top of No. 5.

The formation method is to mix 7 parts of crystal violet lactone, 1 part of polyvinyl alcohol as a binder, and 100 parts of water, then grind and mix for several hours using a ball mill, spin coat on the B layer of the substrate, and disperse in the binder. A deposited film (11 mm thick) of crystal violet lactone was obtained.

(4) Performance test An optical recording element according to the present invention manufactured by the above-mentioned method and a conventional optical disc having a similar structure (all constructed without using a monomolecular film or a cumulative layer thereof) were used as a comparative example. After recording under the following recording conditions using the information storage device shown in FIG. 5, the performance ratio between the two was compared by reading and reproducing.

Recording conditions> Semiconductor laser wavelength 830n+m Laser output 6-9mW Recording frequency 5MHz Optical disk rotation speed 1.80Orpm or higher, readout was performed with a laser output of 1mW, and the results of calculating the signal/noise ratio are shown in Table 2. show.

From the results in Table 2, when comparing No.1 (when the B layer is made of a monomolecular film) and No.006, No.1 has a better signal/
It is recognized that the noise ratio is significantly superior. No
, 1 and No. 1 and B have almost the same film thickness, but this difference in performance appears to be due to the fact that No. 1 has fewer defects such as pinholes than No. 1.

Similarly, No, 2 to No, 5 (B layer is monomolecular cumulative vx
ntx) and No.7, No.
It is recognized that Nos. 2 to 5 are better in signal/noise ratio.

[Effects of the Invention] As explained above, in the optical recording element according to the present invention, the B layer is composed of a monomolecular film or a cumulative film thereof, and the A layer and the light absorption layer are composed of deposited films. 2. There are excellent effects as shown below.

(1) The signal/noise ratio is higher than that of optical recording elements that do not use conventional monomolecular films or their cumulative films.

This can be done by improving the reliability of records.

(2) Physical defects such as pinholes in optical recording elements can be significantly reduced.

(3) Higher density recording is possible than with conventional optical recording elements.

(4) It is possible to increase the area of the optical recording element.

(5) Since the light absorption layer is not interposed between layer A and layer B) 3, coloring efficiency and fidelity are improved.

(6) Since the light absorption layer is not interposed between the A layer and the B layer, the recording layer can be made thinner, and higher density recording is possible.

(7) Materials that have good coloring efficiency and are excellent as coloring agents, etc., but are difficult to form monomolecular films or their cumulative V1 films;
Alternatively, there is an advantage that a material that is difficult to chemically change (synthesize) into a derivative that easily forms a monomolecular film or a monomolecular film or a monomolecular film thereof due to cost considerations can be used for the deposited film.

(8) Since a deposited Mi film is used on a part of the carcass, sensitivity is improved, there is a wide range of material selection during manufacturing, and manufacturing is easy, and it is possible to distinguish between contrast and non-contrast when reading It has an effect on optical properties, such as making it easier to see differences.

[Brief explanation of the drawing]

FIG. 1(a) and FIG.
Figures (a) to 2 (C) t± explanatory diagram showing the recording process of a conventional optical recording element, Figure 3 is a schematic cross-sectional view of the monomolecular cumulative film forming apparatus, and Figures 4 (a) to i4 Figure (C) is a manufacturing process diagram of a monomolecular cumulative film, and Figure 5 is a block diagram of an information storage device.

Claims (1)

[Claims] (1) Layer A consisting of a normally colorless or light-colored color-forming compound and layer B consisting of an auxochrome compound that develops color when in contact with the color-forming compound are laminated, and a light-absorbing layer is further provided, and (a) An optical recording element characterized in that the B layer is composed of a monomolecular film of an auxochromic compound or a layer consisting of a cumulative film thereof.