JPS60161192A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium having excellent long-time presservability and favorable recording characteristics, by a method wherein a layer of a mixture of a specified naphthoquinone coloringmatter or a metallic complex thereof with a stabilizing material is provided as a recording layer of an optical recording medium. CONSTITUTION:5-Amino-8-(subst. anilino)-2,3-dicyano-1,4-naphthoquinone coloring matter or 5,8-(subst. anilino)-2,3-dicyano-1,4-naphthoquinone coloring matter or a metallic comlex thereof and a stabilizing material such as a porphine-type compound, preferably, a metal-free phthalocyanine compound are vapor deposited together on a bsse 10 formed of a glass, an aluminum alloy, a synthetic resin or the like to provide a mixed layer 20. The amount of the stabilizing agent in the mixed layer is 1-50vol%. The recording medium thus obtained can be speedily provided with pits 40 with a small amount of laser energy, and light can be made to be incident on the medium on both the medium face side and the base side at the time of reproduction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical recording medium on which information can be recorded and reproduced using laser light, and more particularly to an optical recording medium using an organic dye.

(Prior art and its problems) Conventionally, Te alloys, Te oxides, organic dyes, etc. have been used as this type of optical recording medium. Organic dyes generally have excellent properties in that highly sensitive and non-polluting media can be produced at low cost, and various attempts have been made to develop media. They can be roughly divided into vapor deposition type and solvent coating type.

In the solvent coating type, for example, as disclosed in JP-A No. 55-161690, polyvinyl acetate, which is a polymer resin, is mixed with Volitester Yellow as a dye using a solvent, and formed on a substrate by a spin coating method. . For this reason, when using resin for the substrate, there is a restriction that a solvent must be selected that does not dissolve the resin.On the other hand, media formed by vapor deposition do not impose restrictions on the selection of the substrate, so it is not practical. It is a desirable medium. However, vapor-deposited dye films generally show deterioration of surface properties due to association (aggregation). This deterioration determines the lifespan of the medium, so in the case of vapor-deposited media, it is important to use a medium with low association. A medium with a sufficient lifespan has not yet been developed. (Objective of the Invention) The object of the present invention is to improve the above-mentioned drawbacks of the prior art and to develop a recording layer mainly composed of an organic dye that has excellent long-term storage stability. An object of the present invention is to provide an optical recording medium having the following characteristics.

(Structure of the Invention) The present invention provides an optical recording medium in which a recording layer is provided on one or both sides of a substrate, and information is recorded and read by a laser beam. 3-dicyano-1,4-naphthoquinone dye or 5,8-(substituted anilino)-2,3-dicyano-
It is characterized by having a mixed layer of a 1,4-naphthoquinone dye or a metal complex thereof and a stabilizing material.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-described configuration.

5-amino-8-(substituted anilino)-2,3-dicyano-1,4-naphthoquinone dye or 5,8-(substituted anilino)-2,3-dicyano-1,4-naphthoquinone dye or metal complex thereof By selecting an alkyl group, an alkoxyl group, an allyl group, an amino group, or a substituted amino group as a substituent for the substituted anilino, the film formability by vapor deposition and the associativity of the vapor-deposited film are superior to those of unsubstituted anilino (-NH@).

The number of carbon atoms in the alkyl group and alkoxyl group of the substituent is 1
-4 is desirable, and an alkoxyl group is more desirable.

These naphthoquinone dyes and their metal complexes exhibit maximum absorption in the near-infrared region, and when a semiconductor laser is used as a recording/reproducing laser, it is expected that the oscillation wavelength will match well with that of a semiconductor laser and a highly sensitive medium can be formed.

Synthesis examples of the naphthoquinone dye and its metal complex are shown below.

First, known 2,3-dichloro-1,4-naphthoquinone is nitrated with nitric acid and sulfuric acid to obtain 5-nitro-2,3-dichloro-1,4-naphthoquinone. Next, cyanation was performed with sodium cyanide to give 5-nitro-2,3-dicyano-1,
4-dihydroxynaphthalene is obtained.

Subsequently, after reduction treatment with stannous chloride and hydrochloric acid, stannous chloride
After oxidation treatment with iron, 5-amino-2,3-dicyano-1,
Obtaining 4-naphthoquinone [I] o [1]I g is thoroughly ground, dispersed in 400 ml of ethanol, and refluxed. To this, 1.23p of p-ethoxyaniline (2 molar ratio)
Add dropwise an ethanol (lorr+l) solution of 0 and stir for 10 minutes under reduction. After the reaction, filter while hot. Cool the P solution with water. Filter the resulting precipitate. After drying, recrystallize from chloroform to obtain 3801n9 (yield 24φ). Refined products (mpzs4
~256°0) is obtained.

The identification results of this purified product are as follows: (1) \max 760nm (in acetonitrile) (
2) Mass spectrometry (M/e) 358, 330, 329 (3
1 element analysis value calculation value C: 67.03% N: 15.64% H: 3
．． Experimental value of 94 cm C2 67.09 cm N: 15.85 cm H: 3.85 cm, this is 5-amino-
8-(p-ethoxyanilino)-2,3-dicyano-1
, 4-naphthoquinone [ll].

Next, dissolve 200 ~ of [1 l) in 300 ml of acetonitrile, add a solution of 72 ~ (1 molar ratio) of cobalt chloride dissolved in 50 ml of acetonitrile, and reflux for 3 hours at the boiling point of acetonitrile. After that, distill under reduced pressure, wash the residue with acetonitrile and rinse the mouth.
After further washing with water and drying, 5-amino-8-(p
A purified product of cobalt complex 130rn9 of -ethoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye was obtained.

When this purified product was analyzed by silica gel thin layer chromatography using acetonitrile as a developing agent, no complex was developed. Note that the Hf value of [Il] is 09.

Other naphthoquinone dyes and metal complexes thereof can be synthesized in the same manner as in the above synthesis example.

Stabilizing materials used in the present invention include B.

kl, M1? , Si, Ca, 8c, Ti, V
, Cr, Mn, Fe, Co, NiCu, Zn
, Ga, Ge, Sm, Sr, 'Y, Zr, Nb
, Tc, Ru, RhPd, Ag, In, So, B
a, La, Hf, Ta, Re, Ir, Pb, BiDy,
Particularly preferred are GeQ, ', S+0, 5i02. Al, 0
3. Cr, 03Y20s, L1120s, Ce
O! , 8rnt Os , Z no , T i
02, Mgt'tC,F, and porphine type compounds. Particularly preferred among the 7] milfine-type compounds are thermometallic phthalozoanine and the central atom (molecule) dsL,i.

Na, Mg, kl, Ca,', I'i,
TiO, V, VO, Cr, Mn, Fe.

Co, Ni, Cu, Zn, Ga, Ge, Y, Mo, R
b, Pd, 8g 11” +Sn, Ba, L*
, Ce, Pr, Nd, Sm, Eu, Gd, D
y, Tb, ErYb, Hf, Os, Pt, Pb
O is a phthalocyanine compound, or a fluorine-substituted product or a chlorine-substituted product thereof.The mixing ratio of the naphthoquinone dye or its metal complex and the stabilizing material is 1% to 50vo.
The most common method of producing a zero mixed layer, preferably selected in the d% range, is codeposition. This is a method of obtaining a mixed layer on a substrate held on an evaporation source by simultaneously evaporating the naphthoquinone dye or its metal complex and a stabilizing material from a separate evaporation source. be.

Alternatively, a pseudo-mixed layer may be formed by alternately stacking thin films of 50 Å or less. As a heating method for the evaporation source, resistance heat, electron beam heating, etc. can be used.
- Tsutaring, ion beam deposition, cluster ion beam deposition, and ion tube brating can be used, and the naphthoquinone dye or its metal complex and the stabilizing material may be formed by separate deposition methods. Various materials can be used as the substrate to support the layer, but glass, aluminum alloys and synthetic resins are generally preferred.Synthetic resins include (1) methyl methacrylate (PMMA) polycarbonate, epoxy, and polyether. Examples include imide, polysulfone, and polyvinyl chloride. The substrate shape can be a disk shape, a tape shape, or a sheet shape. When a semiconductor laser beam is focused on the recording layer formed on the substrate with a lens and irradiated, the recording layer 75 of the irradiated area is removed. The mechanism of this pore formation is not clear, but it is thought to be due to melting and aggregation accompanied by evaporation (sublimation).The size of the pore formed is determined by the focused diameter of the laser beam, Although it depends on the laser power and irradiation time, it is preferably about 0.2 to 3 μm.The laser energy required to form such a hole is small, so the hole can be formed in a short time. . in particular,
7v with wavelength 830nm! ()aA,! When the semiconductor laser beam is converged to a beam diameter of 1.4 μm, holes can be formed with a power in the recording layer of 2 to 13 mW and an irradiation time of 50 to 300 n5ec. As a matter of course,
Holes can be formed even under conditions that exceed the upper limits of the power or irradiation time, but the above conditions are desirable usage conditions. Information is recorded by associating binary information with the presence or absence of holes. Usually, information is recorded by rotating a disc-shaped medium at a constant speed and forming holes in accordance with the recorded information. In the above case, the thickness of the recording layer is 0. O1~
0.5 μm, preferably 0.02-02 μm. The information (holes) recorded in this manner is read out by detecting changes in the amount of light reflected or transmitted from the medium. Generally, a method of detecting reflected light is adopted. This is because the optical system is simpler when detecting reflected light. That is, this is because one optical system can project and collect light. For reading, laser light is continuously irradiated. The amount of light at this time is set to a weak energy that does not cause any shape change to the medium, and is 6% to 6% of the amount of light during normal recording.

There are two directions of incidence of light during recording and reproduction: toward the medium surface and toward the substrate surface. Both orientations can be used with single layer media such as the present example. When the light is incident on the substrate surface side, recording and reproduction can be performed without being affected by dust attached to the medium surface, which is a more desirable form. Note that defects such as dust attached to the substrate surface opposite to the surface on which the medium is formed and defects such as scratches on that surface can be avoided because the beam diameter on that surface is sufficiently large if the substrate thickness is JAR or more. It has little effect on recording and playback.

Information is recorded as a series of holes. The rows of holes generally form multiple concentric or spiral trunks. When regenerating, the light beam needs to accurately track the hole rows of a particular trunk. One way to achieve this is to increase the precision of the rotation mechanism by using air bearings or the like. However, in this case, the rotation system becomes complicated,
Furthermore, it is not practical because it is expensive. More equipment Shiinoke,
This is a method of providing light guide grooves on a substrate. When light enters a groove about the diameter of a beam, it is diffracted.

As the beam center shifts from the groove, the spatial distribution of the diffracted light intensity changes, and the servo system can be configured to detect this and direct the beam to the center of the groove. Normally, the width of the groove is set to 04 to 12 μm, and the depth is set within the range of 1/2 of the recording/reproducing wavelength used. The recording layer is therefore formed on the grooved substrate surface.

Embodiments of the present invention will be described in detail below with reference to the drawings and explanations. .

(Example J) 5-Amino-8-(p-ethoxyanilino)-2,3 was added to one port of a vapor deposition apparatus having two resistance heated boats.
- A dicyano-1,4-naphthoquinone dye is placed in the other boat, a vanadium oxide phthalocyanine dye is placed in the other boat, both boats are heated independently, and the naphthoquinone dye and the phthalocyanine dye are codeposited onto the substrate. , using an acrylic plate with a thickness of 1.2 mm, lQ
Rotated at rpm. The figure shows a cross-section of the medium thus obtained.A mixed layer 2 is placed on an acrylic substrate 10.
0 is provided as a recording layer. The thickness of this mixed layer is 810A, and the mixing ratio of the naphthoquinone dye and the phthalocyanine dye is approximately 10 in terms of the monolayer thickness ratio.
When the optical properties of this medium are measured at a wavelength of 830 nm, the reflectance is 18% and the absorption rate is 5 when it is incident on the substrate.
Semiconductor laser light with a wavelength of 830 nm, which was 4%, was focused by an optical system (not shown) and irradiated onto the medium from the direction of arrow 30. The power of the laser light on the medium surface was 10 mW, and the recording frequency was When recording is performed under the conditions of 2.5 MIIZ and a linear velocity of 13 m/vc, there are 4 holes (bits) in the mixed layer 20.
0 was formed. Such recording was similarly possible even when light was incident from the front side of the medium, that is, from the direction of arrow 50. When the recorded pit is played back with 09mw continuous light, 5
A C of 5 dB was obtained. The long-term storage stability of the medium was evaluated by the following method. The mixed layer was observed under a 1000x optical microscope, and the presence or absence of agglomerated particles on the surface of the film was used as a criterion for deterioration. An accelerated test was performed, and the mixed layer was compared with the naphthoquinone dye alone, showing that the mixed layer deteriorated more. It was difficult.

Comparing the lifespan, when using only the naphthoquinone dye,
Although the lifespan was about 10 years, it was confirmed that the mixed layer according to the present invention had a lifespan of about 20 years or more.

(Example 2) In the same manner as in Example 1, a mixed layer of 5-amino-8-(p-ethoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye and MgF was produced.

The film thickness is 900A, and the mixing ratio is approximately 10:1.

When recorded and reproduced in the same manner as in Example 1, the result was 49 dB.
C was obtained, and the storage stability was also good. Also, Example 1
A similar lifespan was confirmed.

(Example 3) A mixed layer of a cobalt complex of 5-amino-8-(p-methoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye and a copper phthalocyanine dye was prepared in the same manner as in Example 1. The film thickness was 860A, and the aging rate was approximately 8:1.
It is. When recorded and reproduced in the same manner as in Example 1,
A C of 52 dB was obtained, and the storage stability was good. Next, when the lifespan was examined in the same manner as in Example 1, it was found that the naphthoquinone dye complex alone had a lifespan of about 25 years, but in the case of the present invention, a lifespan of 30 years or more was predicted.

(Effects of the Invention) As is clear from the above examples, an optical recording medium that is stable and has good recording characteristics can be obtained by the present invention.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of an optical recording medium according to the present invention, in which lO is a substrate, 20 is a mixed layer, 30
．． Reference numeral 50 indicates the direction of incidence of light, and reference numeral 40 indicates a hole.

Claims (1)

[Scope of Claims] (2) An optical recording medium in which a recording layer is provided on one or both sides of a substrate, and information is recorded and read by a laser beam, wherein the recording layer is 5-amino-8-(substituted anilino)-2, 3-dicyano-1,4-naphthoquinone dye or 5.8-(substituted anilino)-2,3-dicyano-]
, 4-naphthoquinone dye or a metal complex thereof, and a stabilizing material. 2. The optical recording medium according to claim 1, wherein the stabilizing material is a porphine type compound.