JPS6137483A - Optical recording element - Google Patents

Abstract

PURPOSE:To obtain optical recording elements having high reliability and high packing density by providing a layer A of leuco dye, a layer B of phenol compound which develops the color of the leuco body of the dye and a light-absorbing layer existing between the layers A and B, each layer being formed with either a monomolecular film or an accumulated film. CONSTITUTION:The titled optical recording element is composed of a layer-A 2 of a leuco body of dye, a layer-B 4 of phenol compound and a light-absorbing layer 3 of light-absorbing material which exists between the layer A and the layer B. These layers are laminates of either monomolecular film or its accumulated film. The layer-B 4 is supported on a substrate 1, and the substrate, layer B, light-absorbing layer and layer A are laminated in that order. For these reasons, compared to the conventional optical recording element, the titled element has higher packing density and higher signal/noise ratio, thus improving 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 an optical recording device capable of highly reliable and high-density recording using a highly molecularly oriented organic thin film. It is related to the element.

[Background Art] Recently, optical disks have been attracting attention as a central player in 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 something that brings. In addition, the recording element for the optical disk is inexpensive;
2. Description of the Related Art Elements made of organic materials that have features such as ease of manufacture and high-density recording are attracting attention.

Among the conventional techniques using such organic recording materials, a two-component optical recording element that utilizes a coloring reaction caused by contact between a coloring agent and a preservative has been reported (Nikkei Sangyo Shimbun, 1932).
(October 18, 2008).

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

The coloring agent (leuco body) and the stabilizing 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 reflectance, 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 density, the light absorption layer 6 must be as thin as possible, flat, and without uneven thickness. However, in conventional optical recording elements, the light absorbing layer is coated on the substrate by, for example, vacuum evaporation or spin coating, so the thickness is reduced to 2.
If an attempt is made to reduce the thickness to less than 0.00 to 500.08, pinholes tend to occur frequently, and the two components, the coloring agent and the time-setting agent, come into contact with each other at these pinholes and develop color, resulting in 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 increasing the thickness of the film and causing unevenness in recording quality when the substrate of the optical disc 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-density recording. The purpose is to provide an optical recording element that is easy to manufacture and inexpensive. The purpose of 5M of unreleased 1 is to provide a large area optical recording element.

[Means for solving the problem] and [Operation] That is, the present invention is directed to A, which is a leuco form of a normally colorless or light-colored dye.
a layer B consisting of a phenolic compound that develops color when in contact with the leuco form of the dye; and a light absorption layer interposed between the layer A and the layer B, and (a) the layer A is made of a dye. (b) The B layer is a monomolecular film of a phenolic compound or a cumulative film thereof; (c) The light-absorbing layer is a layer of a light-absorbing substance. This is an optical recording element characterized in that it is composed of a layer consisting of a monomolecular film or a cumulative film thereof.

The present invention will be explained in detail below.

The optical recording element according to the present invention utilizes a two-component coloring reaction, and more specifically, it utilizes a coloring reaction between a leuco dye and a phenolic compound that develops a color when it comes into contact with the leuco dye. It is.

Therefore, the optical recording element according to the present invention has an AQ made of a leuco form of a normally colorless or light-colored dye, a B layer made of a phenolic compound that develops color when it comes into contact with the leuco form of the dye, and a layer A and a layer B. It basically consists of a light absorbing layer that is interposed between the layers and absorbs light, generates heat, and melts or sublimates itself.

Examples of the leuco type of the normally colorless to light-colored dye of the A layer used in the present invention include triphenylmethane type, fluoran type, phenothiazine type, auramine type, spiropyran type, etc., and the corresponding compounds contained therein. The details are listed in Table 1.

Next, examples of the phenolic compounds in the B layer that develop color upon contact with the leuco form of the dye include pt-butylphenol, α-naphthol, β-naphthol, phenolphthalein, bisphenol A, 4-hydroxy Diphenoxide, 4-hydroxyacetophenone, 3.5
-xylenol, thymol, hydroquinone, 4-tert-butylphenol, α-naphthol, 4-hydroxyphenoxide, β-naphthol, methyl-4-hydroxybenzoate, catechol, 4-hydroxyacetophenone, resorcinol, 4-tert-octyl Catechol, 4.4'-Secondary-butylidenediphenol, 2.2'-Dihydroxydiphenyl, 2.
2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-bis(4'-oxydiphenyl)propano, 4,4'-isopropylidenebis(2
-tertiary-butylphenol), 4,4'-secanglebutylidene diphenol, pyrogallol, phloroglucin, phloroglucin carboxylic acid, and the like.

In the present invention, both the A layer and the B layer are jlj, a molecular film, or a layer thereof! Since it is formed from a layer consisting of /i film,
For both the leuco dye and phenolic compound mentioned above, it is necessary to use a 11N conductor in which a hydrophilic group, a hydrophobic group, or both groups are introduced into an open site in the molecule.

As the hydrophobic group and the parent group, any commonly used group can be used, but particularly preferably a long-chain alkyl group with 5 to 30 carbon atoms as the hydrophobic group, and as the hydrophilic group, Carboxyl groups and their metal salts (eg cadmium salts) are preferred.

In addition, 11ji J! of A layer and B layer! y is 200A to 1O
A range of JL is desirable - preferably from 1.00OA to 1
This is within the range of

Next, as the light-absorbing substance used for forming the light-absorbing layer in the present invention, a meltable light-absorbing dye that absorbs infrared rays and melts, or a sublimable light-absorbing dye that absorbs infrared rays and sublimates is suitable. .

Examples of such light-absorbing dyes include copper phlocyanine,
Examples include metal phthalocyanines such as vanadium phthalocyanine, alloy layer azo dyes, acidic azo dyes, and xanthine dyes such as fluorescein.

Since the light-absorbing layer is formed from a monomolecular film or a layer consisting of a cumulative film thereof, the light-absorbing substance has a parent group, a hydrophobic group, or both groups introduced at appropriate sites within the molecule. It is necessary to use derivatives.

Any commonly used hydrophobic group and hydrophilic group can be used, but particularly preferred hydrophobic groups include long-chain alkyl groups having 5 to 30 carbon atoms;
As the parent group, carboxyl groups and metal salts thereof (eg, cadmium salts) are desirable.

The thickness of the light absorption layer is preferably in the range of 30A to 1.00OA, preferably in the range of 50A to 20OA.

In addition, the materials used for the substrate in the present invention include:
Semiconductor materials such as silicon, metal materials such as aluminum, preferably reinforced glass, and plastic materials such as acrylic (PMMA), polycarbonate (PC), polypropylene, polyvinyl chloride (PVC), and polystyrene:
1. Ceramic materials are preferred.

In the optical recording collector according to the present invention, layer A is a layer consisting of a monomolecular film of a leuco dye or a cumulative film thereof, and layer B is a layer consisting of a monomolecular film of a phenolic compound or a cumulative film thereof, and a light absorption layer. One of the characteristics is that it is composed of a monomolecular film of a light-absorbing substance or a layer consisting of a cumulative film thereof.

As a method for creating a monomolecular film having such high orderliness and high orientation of molecules or a cumulative layer thereof, for example, 1.
The Langmuir-Prodgett method (La method) developed by Lang+++uir et al. is used. The Langmuir-Prodgett method is based on the Langmuir-Prodgett method, for example, when a lateral molecule that has a parent group and a hydrophobic group in the molecule maintains an appropriate balance between the two (amphiphilic balance), the molecule will react to the parent group on the water surface. 2
tit - This is a method of creating a monomolecular film or a monomolecular cumulative film by utilizing the fact that the monomolecular layer forms downward.

A monolayer on the water surface has the characteristics of a two-dimensional system. When the molecules are sparsely dispersed, the area per molecule A and the surface pressure n
The two-dimensional ideal gas equation, nA = kT, holds true between the two, and the result is ``Gas nc'', where k is Portzmann's constant and T is the absolute temperature.If A is made small enough, intermolecular interaction becomes stronger and becomes a two-dimensional solid °゛condensed film (
or solid film)′°. The condensation film is plastic,
(It can be transferred layer by layer to the surface of carriers having various materials and shapes, such as plates and glass substrates.

Next, the method for forming a JJIL film of a single molecule or a combination thereof of a leuco compound of a dye used in the present invention, a phenolic compound, or an organic molecule having both a hydrophilic group and a hydrophobic group that is a light-absorbing substance will be described in further detail. do.

First, the organic molecule is dissolved in a volatile solvent such as benzene or chloroform, and is spread using a cylinder or the like on the aqueous phase 11 in the water tank 10 of the monomolecular cumulative film forming apparatus schematically shown in Figure i3.

As the solvent evaporates, the organic molecule is transferred to the aqueous phase 11 with the parent wood group 12 facing the water phase and the hydrophobic group 13 facing the gas phase.
Expand on top.

Next, a partition plate (or float) 14 is used to prevent this precipitate (organic molecules) from freely diffusing on the aqueous phase 11 and 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 (2) proportional to the state of aggregation. 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 a surface pressure n suitable for producing a cumulative film. By gently vertically moving the clean substrate 14 up and down while maintaining this surface pressure, the monomolecular film 16 is transferred onto the substrate. The monomolecular film 16 is manufactured as above, but +'lj, the molecular layer cumulative film 1
In step 7, by repeating the above-mentioned operations, a desired two-layer stack of Cl molecule layers is formed.

For example, when a substrate 15 with a hydrophilic surface is lifted out of water in a direction across the water surface, the hydrophilic groups of the organic molecules are removed from the substrate 15.
A side-facing monolayer 16 is formed on the substrate 15 . When the substrate 15 is moved up and down as described above, the I'li molecular layers 1G are stacked one by one in each step. Since the direction of the film-forming molecules is reversed between the pulling process and the dipping process, this method forms a so-called Y-shaped film in which the parent wood groups and hydrophilic groups of organic molecules, and the hydrophobic groups of organic molecules face each other, between each layer. (Figure 4(a)).

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

On the other hand, there is also a method in which the organic molecules are transferred to the substrate surface only when the plate 15 is lowered into water.

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)). The cumulative JA B2 in which the hydrophilic groups in all layers face the substrate 15 side is Z.
It is called Type 11 (Figure f54 (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.

Monomolecular and monomolecular layer stacked films formed on a substrate by the diagonal deposition method have high density and a high degree of order and orientation. , a recording element capable of photothermal recording and having a high-density, high-resolution recording function can be obtained. Furthermore, as can be seen from the principle, these methods are very simple, and a recording element having the excellent recording function as described above can be provided at low cost.

As stated above. In the present invention, the substrate on which the rl molecules 1r2 or monomolecular cumulative film is formed is not particularly limited, but as long as a surfactant is attached to the surface of the substrate.

When the monomolecular layer is transferred from the water surface, the monomolecular layer is disturbed and a good monomolecular layer or monomolecular layer accumulation film cannot be formed, so it is necessary to use a substrate with a clean surface.

The monomolecular 11 or r11 molecular layer cumulative film on the substrate is sufficiently strongly fixed and hardly peels off or peels off from the substrate. Alternatively, an adhesive layer may be provided between the monomolecular layer forming conditions. 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.

An example of the structure of an optical recording element according to the present invention manufactured by the method described above is shown in FIG. 1, as shown in FIG. It consists of three layers 4 made of a phenolic compound and a light absorption layer 3 made of a light absorption substance interposed between layer A and B5, and all of these layers are composed of monomolecular 1.
A laminate consisting of one film or a cumulative film thereof, with three layers 4 on the substrate 1.
It is supported on top and is formed by laminating the substrate/B layer/light absorption layer/A layer in this order.

Furthermore, as another example, the A layer of the laminate may be supported on a substrate, and 4111 layers may be formed in the order of substrate/A layer/light absorption layer/B layer, or the laminate may be stacked two times to form a final layer. The underlying A layer or B layer may be supported on the substrate.

Since the optical recording element according to the present invention is constructed by separating the A layer and the B layer by a light absorption layer, by melting or sublimating the light absorption layer by infrared irradiation and making holes at desired positions, The color-forming compound of layer A and the Bi time-forming compound come into contact and a coloring reaction proceeds, forming a coloring point at the position and recording information.

Therefore, the optical recording element according to the present invention can be mainly used as an optical disc. FIG. 5 shows an example of an information storage device having an optical pickup optical system for writing or reading information from the optical disc.

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.

Writing is performed as follows. The control circuit 27 controls the oscillation of the semiconductor laser 26. Therefore, the input information is converted into an optical signal by the control circuit 27 and the semiconductor laser 2G. The optical signal 28 passes through the optical pickup optical system shown in FIG. 5, forms an image on the recording layer of the optical disc X8 which is rotating synchronously, and is recorded in color by the coloring mechanism described above.

Reading is performed as follows. Low-power continuous wave light emitted from the semiconductor laser 26 is used as reading light. This is because, 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 pickup optical system. This converts the signal into an electrical signal and reproduces and reads it.

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 A to 2,000 A. 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, Be, light absorption layer, etc. 6 Materials for such a protective layer include dielectrics such as 5i02, plastic resins, and other polymers. LB IIQ and the like are preferred.

[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 "%" means "% by weight."

Synthesis Example 1 (Synthesis example of light-absorbing substance) After mixing and dissolving 10 parts of urea on the synthesis side of vanadium phthalocyanine derivative and 1 part of a 10-15% phosphoric acid aqueous solution, further 2 parts of phthalic anhydride and 10 parts of VOCfL2 (vanadyl salt) were added.
% and 8 parts of anhydrous phthalcyanine derivative represented by formula (1) % formula %,
Heated at 100°C for 5 hours. After cooling, 2% dilute N
100 parts of aOH aqueous solution was added, hydrolyzed, and separated by chromatography to obtain 0.1 part of the target substance (/<nadium phthalocyanine derivative) represented by formula (n)].

Synthesis Example 2 (Synthesis Example of Leuco Formation of Dye) Lys Lebiole, Trafton 4-9 Combined with 1 part of m-7 minobenzoic acid derivative represented by the formula (lI[).

1 part of Michler's hydrol represented by formula (IV) was added with 1 part of acid) and refluxed for 8 hours to obtain formula (V) (C:) 12), 70H.

A triphenylmethane derivative represented by was produced.

Next, the triphenylmethane derivative of the product was converted into lead dioxide (
After heating in sulfuric acid for 3 hours in the presence of 1 part), a crystal violet lactone 11^ conductor represented by the formula (Vl) (CH2), 7cH was obtained.

Next, add jl to this? By adding a little more than one aqueous sorter and cyclizing, a crystal violent lactone conductor represented by the formula (■) (C)I2), 7CJ,
Got 2 copies.

Synthesis Example 3 (Synthesis example of phenolic compound) One part of the ortho-xylene derivative represented by the formula (■) (C:J)+7 CH3 was converted into v205 (7
hot air (400°C) using vanadium monoxide as a catalyst.
-500'0), an anhydrophthalic acid derivative represented by the formula (IX) ○ was obtained.

Next, 2 parts of phenol and an appropriate amount of H2soa were added to this and heated at 130°C.

Formula (X) One part of the phenophthalein derivative o represented by the following formula was obtained.

Example 1 (1) Method for forming layer B Thickness: 10 m+a, diameter: 180 mm (1) The glass (disk) substrate of disk-L was sufficiently cleaned. Next r11
A monomolecular cumulative film of a phenolphthalein derivative, which is a phenolic compound, was formed using the single-molecule cumulative device described above.

The monomolecular cumulative film of the phenolphthalein:^ conductor was formed as follows.

(After submerging the board in water so that the board is 1μ perpendicular to the water surface, add a phenolphthalein derivative to a concentration of 2×
A chloroform solution of 10"3 mol/u is dropped onto the water surface to spread a monomolecular film on the water surface.

The surface pressure was set to 30 dyne/cm, and the speed was 2 cm/
Single molecule accumulation of Jj'< 11 by moving the substrate up and down at min to 27 layers! J (Y type 11:i) was created. 1 layer, 50 layers, 200 layers, 400A were created using the same method.
'/・01 molecule cumulative films were prepared for each sample.

(2) Method for forming a light-absorbing layer Next, layer B formed on the glass substrate of each sample in (1) above was coated with a light-absorbing substance using the monomolecule accumulator described above. A single molecule accumulation 1112 of a certain vanadium phthalocyanine derivative was formed.

The monomolecular cumulative 11 di of the vanadium phthalocyanine derivative was formed as follows.

After submerging the substrate in water so that the substrate on which layer B was formed is perpendicular to the water surface, dissolve the vanadium phthalocyanine derivative in chloroform at a concentration of 2 x 10' mol/liter.
Drop onto the water surface at night and spread a monomolecular film on the water surface0
The surface pressure was set to 30 dyne/am, and the speed was 2 cm/
A monomolecular cumulative film (Y-type film) was prepared for each sample by moving the substrate up and down at min.

(3) Method for Forming Layer A Next, crystal violet lactone derivative, which is a leuco form of dye, was deposited on the light absorption layer formed on the glass substrate of each sample in (2) above using the single molecule accumulator described above. A total of 11 g of single molecules were formed.

Monomolecular film f of the crystal violet lactone derivative
The fl film was formed as follows.

After submerging the substrate in the acidic solution of p) 14 so that the substrate on which the B layer and the light absorption layer were formed is perpendicular to the water surface, the crystal violet lactone derivative was added at a concentration of 2×1O°3.
Make a chloroform solution of mol/U and drop it onto the water surface to spread monomolecules on the water surface at a surface pressure of 30 dyne.
/cm, the substrate was moved up and down at a speed of 2 cm/win, and the monomolecular cumulative film (Y-type film) was deposited on each layer shown in Table 2.
was prepared for each sample.

(4) Performance test The optical recording element according to the present invention manufactured by the above-mentioned method and the conventional optical disc having the same structure (all constructed without using a monomolecular film or a cumulative film 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 of the two was compared by reading and reproducing.

<Recording conditions> Semiconductor laser wavelength: 830 layers m Laser output: 6 to 9 mW Recording frequency: 5 MHz Optical disk rotation speed: Reading was performed with a laser output of 1 mW under conditions of t, soorpm or more, and the signal/noise ratio was determined as the second result. Shown in the table.

Notes to Table 2: A comparative example is shown, and each layer was formed using a rotary furnace '71.
This was done using the j method.

From the results in Table 2, when comparing No. + (when each layer consists of one single molecule) and No. 61, it can be seen that No. . Although No. 1 and No. 6 have almost the same thickness, the reason for this difference in performance is thought to be that No. 1 has fewer defects such as pinholes than No. 1.

Similarly, when comparing No. 5 (when each layer consists of a cumulative film of medium molecules) and No. 7, N002-No.
It is recognized that the signal/noise ratio of 0.5 is higher by 1Ω.

[Effect of the invention] As explained above, the optical recording element according to the present invention has the A layer, 8
Since all of the layers and the light-absorbing layer are composed of a monomolecular film or a layer consisting of a cumulative film thereof, there are excellent effects as shown below.

(1) Compared to optical recording elements that do not use conventional monomolecular films or their cumulative films, the signal/H sound ratio is higher, and recording reliability can be improved.

(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.

[Brief explanation of drawings]

FIG. 1 shows an example of an optical recording element according to the present invention 41!
2(a) to 2(c) are explanatory diagrams showing the recording process of a conventional optical recording element, and FIG. 3 is a schematic cross-sectional view of the single molecule cumulative n! Schematic cross-sectional view of the 2-formed equipment, Fig. 4(a)
~Figure 4(c) is a diagram of the production process of the single-molecule cumulative j model and the fifth
The figure is a block diagram of an information storage device.

Claims (1)

[Claims] (1) A usually consists of a leuco form of a colorless or light-colored dye
a layer B consisting of a phenolic compound that develops color when in contact with the leuco form of the dye; and a light absorption layer interposed between the layer A and the layer B, and (a) the layer A is made of a dye. (b) The B layer is a monomolecular film of a phenolic compound or a cumulative film thereof; (c) The light-absorbing layer is a layer of a light-absorbing substance. An optical recording element comprising a layer consisting of a monomolecular film or a cumulative film thereof.