JPS60161193A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium which is stable and has favorable recording characteristics, by a method wherein a layer comprising a specific naphthoquinone coloring matter or a metallic complex thereof as a main constituent is provided as a recording layer of an optical recording medium, and layers of a porpline type compound are provided respectively on both sides of the recording layer. CONSTITUTION:A porpline type compound, a naphthoquinone coloring matter or a metallic complex thereof and the porphine type compound are sequentially vapor-deposited on a base 10 formed of a glass, an aluminum alloy, a synthetic resin or the like to provide layers 20, 30, 40. The naphthoquinone compound may be 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. The porphine type compound may be a metal-phthalocyanine, a phthalocyanine compound having Li, Na or the like as a center atom, or the like. The recording medium thus obtained can be provided with pits 60 speedily and with a small amount of energy.

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-55-161690, polyvinyl acetate, which is a polymeric resin, is mixed with polyester yellow as a dye using a solvent, and is formed on a substrate by a spin coating method. Therefore, 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, a medium formed by vapor deposition is a practically desirable medium because it does not impose restrictions on the selection of a substrate. However, vapor-deposited dye films generally exhibit deterioration in surface properties due to association (aggregation). This deterioration determines the lifespan of the medium, so in the case of vapor deposition media, it is important to use a medium with low association, but a medium with a long enough lifespan has not been developed. An object of the invention is to improve the above-mentioned drawbacks of the prior art and to provide an optical recording medium containing an organic dye as a main component and having excellent long-term storage stability.

(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-1,
The recording layer is composed of a layer containing a 4-naphthoquinone dye or a metal medium thereof as a main component, and is characterized in that layers of a porphine type compound are formed on both sides of the recording layer.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-mentioned 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 of the substituted anilino, the film formability by vapor deposition and the associativity of the vapor-deposited film are improved compared to unsubstituted anilino (-NH-cl).
Better.

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

These naphthoquinone dyes and their metal complexes exhibit extremely strong absorption in the near-infrared region, and when a semiconductor laser is used as a recording/reproducing laser, the oscillation wavelength matches well with that of the semiconductor laser, and it is expected that 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, oxidation treatment with ferric chloride is performed to obtain 5-amino-2,3-dicyano-1,4-naphthoquinone CI]. This was dispersed in 40Qr+J of ethanol and refluxed. This was mixed with 1.23f (2 molar ratio) of Kp-ethoxyaniline in ethanol (l
Qm g) Add the solution dropwise and stir for 10 minutes under reduction. After the reaction, it is filtered while hot, the ν solution is cooled with water, the resulting precipitate is filtered, dried, and recrystallized from chloroform to obtain 380 μm (yield 24%) of a purified product (mp 254-256°0).

The identification result of the purified product is (11'% max 760nm (in acetonitrile)
(21 Mass spectrometry (M/e) 358, 330, 329 (
3) Calculated elemental analysis value C: 67.03% N+15.64% H: 3
．． 94th section experimental value C: 67.09% N: 15.85%
Like H23B5, this is 5-amino-8-
(p-ethoxyanilino)-2,3-dicyano-1,4
- The 0th order, which was confirmed to be naphthoquinone U order, (
11) Dissolve 200η in 300ml of acetonitrile,
Add a solution of cobalt chloride dissolved in 50 ml of acetonitrile and reflux for 3 hours at the boiling point of acetonitrile.Then, distill under reduced pressure and wash the residue with acetonitrile. The cobalt complex of 5-amino-8-(p-ethoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye was obtained in an amount of 1301 ng by washing with water and drying.

When this purified product was analyzed by silica gel thin layer chromatography using acetonitrile as a developing agent, the complex was developed and the Rf! value of (Il) was 09.

Other naphthoquinone dyes and their metal complexes can also be synthesized in the same manner as in the above synthesis examples.Porphine-type compounds used in the present invention include thermometallic phthalonoanine and those in which the central atom (molecule) is Li, f'Lq, Mg. , Al
,Ig,Ca,Ti,TiO,V,VO,Cr,
Mn.

Fe, Co, Ni, Cu, Zn, G; I,
Ge, Y, Mo, Rh, Pd, A4, In,
Sn, Ba, La, Ce, Pr, Nd, Sm
, Eu, od, Dy.

Tb, Er, Yb, Hf, Os, Pt, P
Particularly desirable are phthalocyanine compounds, or fluorine-substituted or chlorine-substituted products thereof.

The recording medium is formed by providing a layer of a porphine compound on both sides of the naphthoquinone dye acid or its metal complex. Various substrates can be used to support the recording layer, but generally glass, Aluminum alloy and synthetic resin are preferable. As a synthetic resin, polymethyl methacrylate)
(PMMA) Polycarbonate, epoxy, polyetherimide, polysulfone, polyvinyl chloride, etc. The substrate shape can be a disk shape, a tape shape, or a notebook shape.

When the semiconductor laser beam is focused by a lens and irradiated onto the recording layer formed on the substrate, the recording layer at the ejection part is removed and holes are formed. Although the mechanism of this pore formation is not clear, it is thought to be due to melting and aggregation accompanied by evaporation (sublimation). The size of the hole to be formed depends on the focused diameter of the laser beam, laser power, and radiation time, but it is preferably approximately 02 to 3 μm, and the laser energy required to form such a hole is small. Therefore, pore formation is possible in a short time. Specifically, the wavelength is 830 nm0VGa
When the As semiconductor laser beam is converged to a beam diameter of 1.4 μm, holes can be formed in the recording layer with a power of 12 to 13 mW' and a radiation time of 50 to 300 r+. Naturally, holes can be formed under conditions that exceed the upper limits of the power or irradiation time, but the above conditions are desirable usage conditions.Recording 0 information makes binary information correspond to the presence or absence of holes. Especially given to others. Information is usually recorded by rotating a disk-shaped medium at a constant speed and forming holes in accordance with the recorded information.

In addition, in the following cases, the thickness of the layer is 0.01 to 0.
．． 5 μm, preferably 0.02 to 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 for reflected light detection is simpler.

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 % to % of the amount of light during normal recording.

There are two directions of incidence of light during recording and reproduction: one on the medium surface and one on 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 are possible 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 1 μ or more. It has little negative effect on recording and playback.

Information is recorded as a series of holes. The rows of holes generally form a number of concentric or spiral tracks. When reproducing, the light beam needs to accurately track the hole array of a specific track. One way to achieve this is to increase the precision of the rotation mechanism by using air bearings, etc. However, in this case, the rotation system becomes complicated,
Furthermore, it is not practical because it is expensive. More desirable is
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.

The spatial distribution of the diffracted light intensity changes as the beam center shifts from the groove, and a servo system can be configured to detect this and direct the beam to the center of the groove. Usually, the width of the groove is set to 04 to 1.2 μm, and the depth is set within the range of - to - of the recording/reproducing wavelength used. The recording layer is therefore formed on the grooved substrate surface.

Examples of the present invention will be described in detail below with reference to the drawings. (Example 1) Copper phthalocyanine dye is put into the first boat of a vapor deposition apparatus having three resistance boats, and the second boat is filled with copper phthalocyanine dye. 5-7
Mi, t-8-(p-ethoxya = IJ/)-2,3-
A dicyano-1,4-naphthoquinone dye was placed, a vanadium oxide phthalocyanine dye was placed in a third boat, and the copper phthalocyania dye, the above naphthoquinone dye, and the vanadium oxide phthalocyanine dye were deposited on the substrate in this order. An acrylic plate with a diameter of 120 m and a thickness of 12 M was used as the substrate. The figure shows the cross section of the medium obtained as follows: 20 copper phthalocyanine dyes on an acrylic substrate 10
is provided, the naphthoquinone dye 30 is provided thereon, and the vanadium oxide phthalocyanine dye 40 is provided thereon.
The thickness of the copper phthalocyanine dye provided with is 50
A, the thickness of the naphthoquinone dye is 800A,
The thickness of the vanadium oxide phthalocyanine dye is 50A. When the optical properties of this medium at a wavelength of 830 nm were measured with the light incident on the substrate, the reflectance was 18% and the absorption rate was 54 cm. Semiconductor laser light with a wavelength of 830 nm was focused by an optical system (not shown) and irradiated onto the medium from the direction of arrow 50.

When recording is performed under the conditions of a laser beam power of 10 mW on the medium surface, a recording frequency of 2.5 M1lz, and a linear velocity of 10 m/E, holes ( 60 pits) were formed. When the recorded pits are played back with Q, 9mW continuous light, the C is 53dB.
/N was obtained. In addition, when the recording power, recording frequency, and linear velocity are changed from the above values, the copper phthalocyanine dye film 20
In some cases, holes (pits) were formed.The long-term storage stability of the medium was evaluated using the following method. The media surface was observed with a 1000x optical microscope, and the presence or absence of aggregate particles generated on the film surface was used as a criterion for deterioration. An accelerated test was performed, and a comparison was made with the case of using only the naphthoquinone dye. It was less likely to deteriorate if it was sandwiched. Estimating the lifespan, it was about 10 years in the case of only the naphthoquinone dye, and about 20 years or more in the structure of the present invention.

(Example 2) In the same manner as in Example 1, vanadium oxide phthalodunine dye and 5-amino-8-(p-ethoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye were added to E on the substrate. , a copper phthalocyanine dye was deposited. The film thicknesses are 5()A, 750A, and 50A, respectively. When the optical characteristics of this medium at a wavelength of 830 nm were measured with the light incident on the substrate, the reflectance was J9 and the absorption was 53. When recorded and reproduced in the same manner as in Example 1, a C of 5 JdB was obtained, and the storage stability was good. 5-amino-8-(p-ethoxyanilino)-2
, 3-dicyano-1,4-naphthoquinone dye, and vanadium oxide phthalocyanine dye were deposited in this order. The film thicknesses are 100^, 70o hole, and too^, respectively. When the optical characteristics of this medium at a wavelength of 830 nm were measured with the light incident on the substrate, the reflectance was 18% and the absorption rate was 53%. Example 1
When recorded and played back in the same manner as above, the C/N was 48 dB.
was obtained, and the storage stability was also good.

(Example 4) In the same manner as in Example 1, nickel phthalocyanine color L 5-amino-8-(p--c)xyanilino)-2,3-dicyano-1,4-naphthoquinone dye, oxidized Vanadinium phthalozoanine dyes were deposited in this order. The film thickness is IQOλ and 75o^, respectively.

There are 50 Af. When the optical properties of this medium at a wavelength of 830 nm are measured with the substrate incident, the reflectance is 17% and the absorption rate is 54%.
Met. When recording and reproducing were carried out in the same manner as in Example 1, an Ω pair of 50 du was obtained, and the storage stability was also good.

(Example 5) Copper phthalocyanine dye was placed in one boat of a vapor deposition apparatus having two resistance heating boats, and 5-amino-8-(p-ethoxyanilino)-2,3-dinoano-1 was placed in the other boat. , 4-naphthoquinone dye, and the copper phthalocyanine dye, the naphthoquinone dye, and the copper phthalocyanine dye were deposited on the substrate in this order.

When the optical properties at 830 nm were measured with the substrate incident, the reflectance was 18% and the absorption rate was 54%. Recording and reproduction were performed in the same manner as in Example 1, and the result was 48 dn. (2) was obtained, and the storage stability was also good.

(Example 6) In the same manner as in Example 5, vanadylamphthalocyanine oxide dye and 5-amino-8-(p-ethoxyanilino)-2,3-dinoano-1,4-naphthoquinone dye were deposited on the substrate. A cobalt complex and a vanadium oxide phthalocyanine dye were deposited in this order. Film thickness is 50A, 700A, 50A, respectively.
It is A. When the optical properties of this medium at a wavelength of 830 nm were measured with the light incident on the substrate, the reflectance was 18% and the absorption rate was 53%. When recording and playing back in the same manner as in Example 1, 5
A C/N of 0 dB(7) was obtained, and the storage stability was also good. When the lifespan was estimated in the same manner as in Example 1, it was confirmed that the naphthoquinone dye complex alone would last about 25 years, and the structure of the present invention would last about 30 years or more.

(Example 7) In the same manner as in Example 5, a nickel phthalocyanine dye, a 5-amino-8-(p-ethoxyanilino)-2,3-dicyano-1,4-naphthoquinone dye, and a nickel phthalocyanine dye were placed on the substrate. The dye was deposited in this order. The film thicknesses are 1 (IOA, 790' and 40^), respectively. When the optical properties of this medium at a wavelength of 830 nm were measured with the substrate incident, the reflectance was 18% and the absorption rate was 53%. Example J and When recording and playing back in the same manner, a C/N of 51 dB was obtained, and the storage stability was also good.Examples 2, 3, and 4
, 5.7 also had the same lifespan as Example 2.

(Effects of the Invention) As is clear from the above examples, the present invention does not provide an optical recording medium that is stable and has good characteristics.

[Brief explanation of drawings]

Claims (1)

[Claims] In 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,
The recording layer contains 5-amino-8-(substituted anilino)-2,
3-dicyano-1,4-nara 14 fufu dye, or 5
, 8-(substituted anilino)-2,3-dicyano-1,4-
1. An optical recording medium characterized in that a layer containing a naphthoquinone dye or a metal complex thereof as a main component and a layer of a porphine compound are formed on both sides of the recording layer.