JPS59227488A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium which is very high in the S/N ratio with a high sensitivity while stable and less poisonous by forming a recording layer comprising a composite layer in which metal or semiconductor fine particles are dispersed into a metal oxide thin film. CONSTITUTION:An optical recording medium is provided with a recording layer 1 comprising a composite layer in which metal or semiconductor fine particles are dispersed into a metal oxide thin film on the surface 4 to be irradiated with an energy ray such as ultraviolet ray of an organic high molecular matter layer 2 formed on a substrate 3. The organic high molecular matter includes polymethyl methacrylate, methylmethacrylate and a copolymer thereof with a copolymerizable vinyl monomer and polystylene, stylene and a copolymer thereof with a copolymerizable vinyl monomer. The metal or semiconductor used in the recording layer is, for example, Sn, In, Ge, Sb, Pb, Al, Zn, Cu, Ag, Au viewed from a lower toxity and alloys mainly composed thereof and the metal oxide is preferably oxides of Sn, In, Al, Zr and Zn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to reduce the change in reflectance or transmittance caused by deformation or removal of the energy ray irradiated portion of the recording layer by melting or the like by irradiating it with energy rays such as laser light. The present invention relates to a recording medium suitable for optically recording and reproducing information.

The properties required for optical recording media such as optical discs are as follows:
These include high recording sensitivity in the wavelength range of the laser used as the recording light source, high signal-to-noise ratio of the reproduced signal, high recording density, excellent storage stability, and low toxicity.

In so-called heat mode recording media, in which the recording layer melts and forms a focus when the temperature of the laser beam irradiation area rises, in order to increase the recording sensitivity, the recording layer must have a high spectral absorption rate, a high melting point , specific heat and thermal conductivity are required to be low, and it is desirable that the recording layer be thin. In order to increase the signal-to-noise ratio of the reproduced signal, it is necessary to make sure that the bits have the same shape and size and that there is no disturbance around the focus, and that when using reflected light for reproduction, the recorded and unrecorded areas are In addition, in order to increase the recording density, the thermal conductivity is required to be low. Furthermore, in order to obtain a recording medium with excellent storage stability, the recording layer is required to have high oxidation stability and moisture resistance.

The currently available recording medium for lasers is one in which a thin film of tellurium or a tellurium alloy such as a tellurium-arsenic alloy is formed as a recording layer on a glass or plastic substrate. Tellurium and tellurium alloy thin films are
It has high light absorption rate in the visible to near infrared wavelength range, low thermal conductivity, and low melting point, so it has high recording sensitivity, and the bit shape and size are easy to match, and it is suitable for the visible to near infrared wavelength range. Since it has an appropriate reflectance, it has properties suitable for a heat mode laser recording medium, such as being able to obtain a reproduced signal with a high signal-to-noise ratio using reflected light. However, the tellurium thin film and the orlu-arsenic alloy WIJIli2 have drawbacks such as low oxidation stability and high toxicity. Attempts have been made to improve the oxidation stability by adding selenium to tellurium or tellurium-arsenic alloys, or by using low tellurium oxides, but so far no satisfactory results have been obtained, and the toxicity No effective measures have been found for this.

In terms of toxicity, it is advantageous compared to tellurium-based recording media to form a dye or a layer in which the dye is dispersed in a polymer on a glass or plastic substrate, or on a reflective layer such as aluminum provided on the substrate. There is a recording medium that has

However, the absorption wavelength of dyes is generally on the shorter wavelength side than red light, and is in the oscillation wavelength range of 750 nm to 85 nm, which is the oscillation wavelength range of semiconductor lasers, which are expected to become the mainstream of recording light sources in the future.
Since a stable dye that exhibits large absorption in the 0 nm region cannot be obtained, a practical dye-based recording medium using a semiconductor laser as a recording light source has not been obtained.

As a result of intensive research aimed at completing optical recording media with low toxicity, excellent oxidation stability, and water resistance, the present inventors discovered that a layer of organic high molecular weight material such as polymethyl methacrylate coated on a substrate. is irradiated with energy rays such as ultraviolet rays, and a recording layer consisting of a composite layer in which fine metal or semiconductor particles are dispersed in a metal oxide thin film, or a thin film of a metal or semiconductor thin film and a metal oxide thin film is formed on the ultraviolet irradiated surface. It was discovered that an optical recording medium with high sensitivity, an extremely high signal-to-noise ratio, stable and low toxicity can be obtained by forming a recording layer in which these are alternately laminated, and the present invention was achieved based on this discovery.

The gist of the present invention is to provide a light beam characterized in that a recording layer made of a metal or semiconductor and gold-N oxide is provided on the energy ray irradiated surface of an organic polymer layer irradiated with energy rays. It lies in the mechanism and composition of the recording medium.

FIG. 1 shows an example of the layer structure of the optical recording medium of the present invention.

In FIG. 1, a recording layer 1 made of a metal or a semiconductor and a metal oxide is provided on a surface 4'' irradiated with energy rays such as ultraviolet rays of an organic polymer layer 2 formed on a substrate 3. ). In this optical recording medium, energy rays such as laser beams incident from the substrate side or the opposite side to the substrate are absorbed by the recording layer, and the recording layer is melted or fluidized by the generated heat, forming bits. Recording and reproduction is performed by utilizing changes in optical properties such as light reflectance and transmittance of the recording layer portion of the medium that is irradiated with energy rays and the recording layer portion that is not irradiated with energy rays.

The organic high molecular weight substance used in the optical recording medium of the present invention has a property that a part of the main chain is easily cut off by irradiation with energy rays such as ultraviolet rays, and the average molecular weight is reduced.
Specific examples include polymethyl methacrylate, a copolymer of methyl methacrylate and a vinyl monomer copolymerizable with it, polystyrene, a copolymer of styrene and a vinyl monomer copolymerizable with it, polyacrylonitrile,
Examples include acrylonitrile and copolymers of vinyl monomers copolymerizable with acrylonitrile. In particular, when a methyl methacrylate polymer or a styrene polymer is used, an optical recording medium with high sensitivity and a high signal-to-noise ratio can be obtained. Examples of vinyl monomers that can be copolymerized with methyl methacrylate include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, and methacrylic acid alkyl esters such as ethyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. Esters, aromatic vinyl monomers such as styrene, α-methylstyrene and p-chlorostyrene, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, dimethyl fumarate, dibutyl fumarate, dimethyl maleate, Dialkyl esters of unsaturated dicarboxylic acids such as dibutyl maleate, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as vinyl ethyl ether and vinyl ethyl ether, chlorinated vinyl monomers such as vinyl chloride and vinylidene chloride. Examples include the body. Examples of vinyl monomers that can be copolymerized with styrene include alkyl esters of methacrylic acid or acrylic acid such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methyl acrylate, and ethyl acrylate, and acrylonitrile. , unsaturated nitrile monomers such as methacrylonitrile, α-methylstyrene, m-methylstyrene,
Examples include aromatic vinyl monomers such as p-methylstyrene, 0-chlorostyrene, m-chlorostyrene, and p-chlorostyrene, and unsaturated carboxylic acids such as maleic anhydride.

The thickness of the organic polymer layer must be 500 or more. Yes 18! If the thickness of the polymer layer is less than 500 Å, an optical recording medium with high sensitivity and high signal-to-noise ratio cannot be obtained). Examples of energy rays irradiated to the organic high molecular weight material of the optical recording medium of the present invention include ultraviolet rays, electron beams, X-rays, etc., but in particular, when irradiating ultraviolet rays with a wavelength of 190 to 420 nm at a rate of 10 mJ/cm or more An optical recording medium with excellent sensitivity and signal-to-noise ratio can be obtained.

Examples of metals or semiconductors used in the recording layer of the optical recording medium of the present invention include Sn, In, Ge1S.
b,,Pb,81. ．． Zn.

Examples include Cu, Ag, 811SBi, SesTe, and alloys containing these as main components. Examples of metals or semiconductors that are preferable from the viewpoint of low toxicity include Sn,...
In, GCs sb, pb, ^1. ．． Zn, Cu,
Ag.

Examples include static and alloys containing these as main components. The characteristics of the above metals or semiconductors include high reflectance in the oscillation wavelength range of semiconductor lasers, low melting point, low toxicity, and high stability in air, so these metals or semiconductors are the main components. When using such an alloy, care must be taken not to lose the above characteristics.

The metal oxide used in the recording layer of the optical recording medium of the present invention must have excellent chemical stability and low thermal conductivity. Preferred examples include Sn and In.
, AI, Zr and Zn oxides, but especially S
When an oxide of n or In is used, a recording medium with excellent stability in air, high sensitivity, and a high signal-to-noise ratio of a reproduced signal can be obtained. Examples of Sn or In oxides include the chemical formulas SnO2, InJj, and 5nOz-x, Inx03-x.
low oxides such as Snl-Sn1-y, Ina-zNz
Examples include 5nOx such as 03, ■nS OJ doped with a different metal. Here, X% Z is 0.5 or less, y is a positive number of 0.25 or less, M is Sb, In.

N represents a metal such as Sn, Ge, Pb, or Zn.

The recording layer in the optical recording medium of the present invention is a composite layer in which fine particles of the metal or semiconductor are dispersed in the metal oxide thin film, or a laminated film of the S film of the metal or semiconductor and the metal oxide thin film. However, especially when a composite layer in which the metal or semiconductor fine particles are dispersed in the metal oxide thin film is used in the recording layer, an optical recording medium with high sensitivity and a high signal-to-noise ratio can be obtained. The filling rate of metal or semiconductor fine particles in the composite layer is preferably 0.3 or more and 0.95 or less.

If the filling factor is 0.3 or less, the absorption coefficient of the composite layer for energy rays such as laser light decreases, and the temperature at which the composite layer melts and fluidizes increases, resulting in a decrease in the recording sensitivity of the resulting optical recording medium. There is a tendency to When the filling Mt ratio becomes 0.95 or more, contact between metal or semiconductor particles dispersed in the composite layer begins, and the metal or semiconductor particle size increases, resulting in irregularities in the size and shape of recording bits. As a result, there is a tendency for the S/N ratio to decrease, and the thermal conductivity of the composite layer also increases, so that recording sensitivity tends to decrease. In the optical recording medium of the present invention, when a composite layer in which the above-mentioned metal or semiconductor fine particles are dispersed in a metal oxide is used for the recording layer, the purpose of increasing the sensitivity and the contrast between the recorded area and the unrecorded area is to The recording layer can also be formed by laminating composite layers of different types of metals, semiconductors, and oxides, or by laminating the composite layer and a thin film of the metal or semiconductor.

In the optical recording medium of the present invention, the thickness of the recording layer is preferably 50 Å or more and 2000 Å or less. When the thickness of the recording layer is 2000 Å or more, the volume of the energy ray irradiated area of the recording layer increases, and the density of energy absorbed when irradiated with energy rays decreases, resulting in a decrease in the recording sensitivity of the recording medium. Furthermore, the shape around the formed bit tends to be disturbed, making it difficult to increase the S/N ratio. Record? ? If the layer thickness is 50 Å or less, the difference in reflectance or transmittance between the recorded portion and the unffa recorded portion of the recording medium will be small, resulting in a low contrast, making it difficult to increase the S/N ratio. When the optical recording medium of the present invention is used in a reflective optical disc, a more preferable thickness range of the recording layer is 10
It is 0 to 12 and 1000 Å or less.

In one embodiment of the optical recording medium of the present invention, an organic polymer layer is provided on a substrate, and after irradiating the organic polymer layer with energy rays such as ultraviolet rays, the organic polymer layer is exposed to energy rays such as ultraviolet rays. A recording layer is formed on the irradiation side surface. The substrate can be a metal plate such as aluminum, a glass plate, methyl methacrylate polymer, styrene polymer, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polybutylene terephthalate!・, polyamide and epoxy resin, diallyl phthalate polymer,
diethylene glycol bisallyl carbonate polymer,
A sheet or film of thermoplastic or thermosetting resin such as polyphenylene sulfide, polyphenylene oxide, polyimide, etc. is used. In particular, the substrate may contain organic polymers such as polymethyl methacrylate, a copolymer of methyl methacrylate and a vinyl monomer copolymerizable with it, polystyrene, or a copolymer of styrene and a vinyl monomer copolymerizable with it. When using a molecular weight material, after irradiating the surface of this substrate with energy rays such as ultraviolet rays, a recording layer is formed on the surface of the substrate that has been irradiated with energy rays, and an organic polymer layer is then used. An optical recording medium having a structure not shown in FIG. 2 is obtained.

Furthermore, when using an organic high molecular weight material for the substrate as described above, a substrate having pre-groups on the surface is manufactured by performing cast polymerization, compression molding or injection molding using a mold or stamper, and then this pre-group of the substrate is used. The optical recording medium of the present invention can be obtained by irradiating the surface on which the groups are formed with energy rays such as ultraviolet rays and then forming a recording layer on the irradiated surface.

When the optical recording medium of the present invention is used as an optical disc in which recording light and reproduction light enter through a substrate,
The substrate is a glass plate, or a methylmeccrylate-1 polymer, a styrene polymer, polyvinyl chloride, a diethylene glycol bisallyl carbonate polymer, or an epoxy resin I+). It is necessary to use a transparent plastic sheet such as

The method for manufacturing the recording medium of the present invention will be explained below with reference to another diagram of the layer structure.

The recording medium having the structure shown in FIG. 1 coats a substrate 3 with an organic polymer I-2, then irradiates energy rays such as ultraviolet rays from above the figure, and records on the surface 4 irradiated with the energy rays. Obtained by forming layer 1. In order to coat the organic polymer layer 2 on the substrate 3, the organic polymer may be dissolved in a solvent or emulsified using methods such as spin cord, roll coating, or dip coating, physical vapor deposition, A method such as plasma polymerization is used. t
After coating the polymer layer 2, this layer is irradiated with energy rays.

As a specific example, a xenon-mercury lamp, a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, etc. are used as the energy source,
Ultraviolet rays with a wavelength of 190 to 420 nm] OmJ/c
Irradiate more than a. The intensity of ultraviolet rays on the surface of the organic polymer layer is preferably 10 ml/c+4 or more.

When using ultraviolet rays as the energy beam as described above, optical recording media with excellent recording sensitivity and signal-to-noise ratio can be obtained by using a xenon-mercury lamp, high-pressure mercury lamp, etc., which have a large spectral output at a wavelength of 300 nm or less as a radiation source. It will be done. In addition, when substances generally called photopolymerization initiators and photosensitizers are added to the organic polymer layer, the recording sensitivity and S/N can be improved even when using a radiation source with a small spectral output at a wavelength of 300 nm or less.
An optical recording medium with an excellent ratio can be obtained. Examples of Kojusha initiators and photosensitizers include benzoin alkyl ether U11.2.2-dimethoxy- such as benzoin isobutyl ether and benzoin isopropyl ether.
2. Penzyl ketals such as phenylacetophenone,
Acetophenone derivatives such as jetoxyacetophenone,
Examples include ketones such as benzophenone, benzyl, and methyl-0-benzoin benzoate.

The amount of ultraviolet rays irradiated should be 10 mJ/cJ or more, and there is no particular upper limit, but when manufacturing an optical recording medium with the structure shown in Figure 2 using an organic high molecular weight material such as polymethyl methacrylate for the substrate, Care must be taken to ensure that the mechanical strength of the substrate does not deteriorate or deform due to heat due to ultraviolet irradiation. In this case, by using a xenon-mercury lamp or a high-pressure water bank as the radiation source and selecting the irradiation amount appropriately, high sensitivity and high signal-to-noise ratio can be achieved without deterioration or deformation of the mechanical strength of the substrate. A high quality recording medium can be obtained.

The starting material medium of the present invention is obtained by irradiating the organic polymer layer provided on the substrate with energy rays as described above, and then forming a recording layer on the surface irradiated with the energy rays. In order to form the recording layer, a vacuum deposition method, an ionization deposition method, an ion blating method, a cluster ion beam deposition method, a sputtering method, etc. are used. When using a composite layer in which metal or semiconductor fine particles are dispersed in a metal oxide as a recording layer, the metal or semiconductor and the metal oxide are placed in separate crucibles and placed in a vacuum of less than I x 10" x 11 g. At the same time, the ionized particles are evaporated and deposited.Also, an ion blating method can be used in which ionized particles are accelerated by applying a DC voltage to the substrate side at the same time as ionization.Also, a metal or semiconductor target and a metal oxide target can be used. A composite layer can also be formed by simultaneous sputtering.

In any case, when forming a composite layer, a composite layer with a predetermined metal or semiconductor filling rate and thickness can be obtained by separately controlling the vapor deposition rate and sputtering rate of the metal or semiconductor and metal oxide. When using a recording layer in which a thin film of a metal or semiconductor and a thin film of a metal oxide are alternately deposited, the metal or semiconductor and the metal oxide are alternately vapor-deposited or A recording layer is formed by sputtering.

The recording layer in the optical recording medium of the present invention is extremely stable under normal environments, and there is no need to provide a special protective layer. It is possible to provide a protective layer on the recording layer for the purpose of preventing this from occurring. As the protective layer, inorganic materials and organic polymer materials such as 5i02, 81λOs, Tool, etc. are used.

In the optical recording medium of the present invention shown in FIGS. 1 and 2,
When the organic polymer layer 2 and the substrate 3 are transparent, the recording light and the reproducing light are incident from above (or may be made from below).

The optical recording medium of the present invention is characterized by low toxicity, high sensitivity, excellent stability in air, and extremely high signal-to-noise ratio. Although the reason why the optical recording medium of the present invention exhibits the above-mentioned excellent characteristics is not necessarily clear at present, it can be estimated as follows.

In the optical recording medium of the present invention, when the high molecular weight material layer is irradiated with energy rays such as violet [rays], the main chain is damaged especially near the surface irradiated with the energy rays. It is cleaved and its molecular weight decreases, resulting in a lower surface energy. On the other hand, recording pits are formed by moving the recording layer that has been melted or fluidized by irradiation with energy rays such as laser light. Since the surface energy of the organic polymer layer is low, it is difficult to melt or fluidize the organic polymer layer.
It is thought that the difference in surface energy with W increases, and the melted or fluidized recording layer moves smoothly.

Alternatively, when the recording layer is irradiated with a laser beam, if the energy of the laser beam melts a portion of the organic polymer layer whose molecular weight has been reduced by the energy ray irradiation, the recording layer that has been melted or fluidized by the laser beam irradiation may be It is also conceivable that the particles move together with the ti layer and become in a state where it is easy to form bits.

As a result, pits with uniform shape and size are formed with low irradiation energy, so that an optical recording medium with high sensitivity and a high signal-to-noise ratio can be obtained. In addition, the metals, semiconductors, metal oxides, etc. used in the recording layer of the optical recording medium of the present invention are all stable in air and water, and have low toxicity. In addition to being used as image files, document files, data files, and external memory for computers, they can also be used as tapes, cards, microfiche, etc. that can be directly recorded and reproduced with laser light.

The R'f' 8411 of the present invention will be illustrated below using examples, but the present invention is not limited to these examples.

Example 1 A solution of polymethyl methacrylate-1 (Acricon, manufactured by Mitsubishi Rayon) in methyl ethyl ketone was applied onto a glass disc-shaped substrate with a thickness of 1.2 m+m, an outer diameter of 300 mm, and an inner diameter of 35 mm using a spinner. It was coated and dried to form a polymethyl methacrylate layer with a thickness of 3 μm. The obtained substrate having the polymethyl methacrylate layer was heated to a light intensity of 30 ml/c at a wavelength of 450 nm or less using a condensing irradiation device having a high-pressure mercury lamp with a lamp output of 80 W/cm.
n! By passing through the area using a belt conveyor, 120 mJ/
Ultraviolet light with energy of cn+ was irradiated.

Place the glass foil plate having the polymethyl methacrylate I layer, which has been irradiated with a single purple ray, into the chamber of a vacuum evaporation device as described in 2. Sn (manufactured by Furuuchi Chemical Co., Ltd., 20φX 10
mat, purity 99. ! l 9%) and 5nOx
(manufactured by Furuuchi Chemical, 18φx5m++t, t4 degree 99.
99%> and rotate the board at a speed of 20 rpm.
υ, Sn and SnO2 were irradiated with electron beams from separate electron guns at a temperature of 2 x 101wm l1g, and the evaporation rate of Sn and SnO2 was set at a node, and polymethyl methacrylate was deposited. An optical recording medium having the structure shown in Fig. 1, which has a recording layer consisting of a composite layer in which Sn fine particles with a thickness of 270 layers and a Sn filling rate of 0.8 are dispersed in a density of 5 nOz on the ultraviolet irradiated surface of the layer. was produced.

While rotating the obtained disk-shaped optical recording medium at a speed of 1800 revolutions per minute, the rotation frequency was 1.
Semiconductor laser modulated during 00nsec pulse (Hitachi +1LP-1600, oscillation wavelength 830nm)
When recording was performed by focusing and irradiating the oscillated light onto the recording layer to a beam diameter of 1 μm through a collimator lens, a condensing lens, and a substrate, it was found that the disk required to form a focus with a minor axis of approximately 1 μm The laser beam intensity on the recording surface "2" was 6 ridges. In addition, the recorded signal was reproduced using a semiconductor laser similar to that used for recording at a laser light intensity of 1 mW, and the CN ratio was measured with a spectrum analyzer under the conditions of a reference signal L) Mllz and a band T'll 30 K11z. It was 52dB.

Comparative Example 1 A glass disc-shaped baffle plate similar to that used in Example 1 was attached to the chamber of a vacuum evaporation apparatus, and the substrate rotation speed was 2.
Using an electron beam evaporation method at 0 rpm and a vacuum level of 2 x 10" mm tlg, Sn and SnO2 were co-evaporated onto the surface of the glass substrate while adjusting the evaporation rate respectively in the same manner as in Example 1. Sn charge fee for 260 people is ￥
A sample was manufactured in which a composite layer in which Sn with a tZa of 0.8 was dispersed in SnOλ was formed on a glass substrate.

The obtained disk-shaped sample was subjected to a repeated treatment of 1.00 nsec at a frequency of 5 MIIz in the same manner as in Example 1.
I tried recording with a semiconductor laser beam modulated during the pulse, but the laser beam intensity on the recording surface of the disk was 12 mW.
But I couldn't form a pin.

As shown above, 5nlk particles are 5nO on a glass substrate.
It is clear that the sample in which the composite layer dispersed in Z is directly formed has significantly lower sensitivity than the optical recording medium of the present invention.

Comparative Example 2 Glass disc-shaped glass similar to that used in Example 1, I
- A polymethyl methacrylate layer with a thickness of 3 μm was provided on the second plate in the same manner as in Example 1, and the substrate having the obtained polymethyl methacrylate layer was attached to the chamber of a vacuum evaporation apparatus. Sn and SnO under the same conditions as 1.
2 to a thickness of 2 on the polymethyl methacrylate layer.
70 people, 5n of Sn fine particles with a Sn filling rate of 0.8
(A sample was prepared in which a composite layer dispersed in 12 was formed.

The obtained disk-shaped sample was subjected to the same method as in Example 1 at a repetition frequency of 5 Mllz for 100 nsec.
When recording was performed with a semiconductor laser beam modulated to a pulse l+ of
m1l, and as in Example 1, the reference signal 5 Mllz
, the CN ratio measured with a spectrum analyzer under the conditions of band Tll 30 K11z was 41 dB.

As shown above, a sample obtained by directly forming a recording layer on a polymethyl methacrylate layer provided on a glass substrate without irradiating energy rays such as ultraviolet rays can be used in the optical recording medium of the present invention. Recording sensitivity is low compared to
Furthermore, the CN ratio also becomes low.

Example 2 A disk-shaped glass plate similar to that used in Example 1 was coated with
Using the same method as in Example 1, the j width shown in Table 1 was 3 μ.
Form a layer of a 1M molecular weight substance with a tl of m, and then
1 was applied to the iM polymer layer using the same method as in Example 1.
Ultraviolet light with an energy of 20 mJ/cnl was irradiated.

Using the same method as in Example 1, fine particles of the metals shown in Table 1 were applied to the organic polymer material layer which had been exposed to the ultraviolet rays 1 obtained as described above. The metal filling rate is 0. In 1985, an optical recording medium with a recording layer formed of a composite layer of 280 layers in thickness was manufactured.

When recording and reproducing was performed on the obtained disc-shaped optical recording medium under the same conditions as in Example 1, the laser light intensity on the recording surface of the disc required to form a bit with a short axis of approximately 1 μm, Table 1 shows the CN ratio.

Example 3 Five disk-shaped sheets made of polymethyl methacrylate made by a casting method with a thickness of 1.2 mm, an outer diameter of 300 mm, and an inner diameter of 35 mm were prepared, and 4 of them were heated with a lamp output of 80 W/cm. By using a belt conveyor to pass through a region with a light intensity of 30 mW/ctA at a wavelength of 450 nm or less using a pole-tip irradiation device equipped with a high-pressure mercury lamp, the polymethyl methacrylate sheet I was produced as shown in Table 2. Irradiated with energy ultraviolet rays.

The four polymethyl methacrylate sheets obtained as described above and irradiated with ultraviolet rays were attached to the chamber of a vacuum evaporation apparatus, and the ultraviolet irradiated surface of the polymethyl methacrylate sheet was An optical recording medium having the structure shown in FIG. 2 was manufactured, having a recording layer having a thickness of 300 mm and consisting of a composite layer in which Sn fine particles with a Sn filling factor of 0.85 were dispersed in SnOλ.

When recording and reproducing the obtained disc-shaped optical recording medium under the same conditions as in Example 1, the minor axis was approximately 1 μm.
Table 2 shows the laser light intensity and CN ratio on the recording surface of the disk necessary to form the bits.

For comparison, the recording and reproducing characteristics of a sample in which a recording layer was directly formed on the surface of the remaining polymethyl methacrylate sheet without UV irradiation are shown in Table 2 as sample number 3-5. shown at the same time.

Table 2 Example 4 Nine polymethyl methacrylate sheets similar to those used in Example 3 were prepared, and these sheets were exposed to 90 mJ/cl using the same ultraviolet irradiation device as in Example 3.
irradiated with ultraviolet rays of energy.

Using the same method as in Example 1, fine particles of the metals or semiconductors shown in Table 3 were applied to the ultraviolet irradiated surface of the polymethyl methacrylate sheet that had been irradiated with the ultraviolet rays obtained as described above. An optical recording medium having a recording layer consisting of a composite layer having metal or semiconductor filling ratios and film thicknesses shown in Table 3 was manufactured.

When recording and reproducing was performed on the obtained disc-shaped optical recording medium under the same conditions as in Example 1, a bottle with a minor axis of approximately 1 μm was obtained! Table 3 shows the laser light intensity and CN ratio on the recording surface of the disk necessary to form .

Example 5 A sheet of polymethyl methacrylate similar to that used in Example 3 was irradiated with ultraviolet rays having an energy of 90 mJ/cn using the same ultraviolet irradiation device as in Example 3.

The ultraviolet irradiated polymeg obtained as described above
methacrylate sheet with a diameter of 200 tuna SnO and SB targets (both made by Furuuchi Chemical, purity 9).
9.9%), and while rotating the polymethyl methacrylate sheet, a layer of SbM with a thickness of 30 mm was first formed on the ultraviolet irradiated surface of the sheet, and then a layer of SbM was formed on the SbM. Form a SnOλ with a thickness of 20 μm. By repeating this operation 5 times and finally forming SbM with a thickness of 30 people, 5bFl 6 Jm with a thickness of 30 people and 5 layers of 5n02 with a thickness of 20 people sandwiched between the SBM. An optical recording medium having a recording layer with a thickness of 280 layers was manufactured.

When recording and reproducing the obtained disc-shaped optical recording medium under the same conditions as in Example 1, the minor axis was approximately 1 μm.
The laser beam intensity at the recording surface of the disk required to form pits was 10 mL and the CN ratio was 48 dB.

Example 6 A sheet of polymethyl methacrylate similar to that used in Example 3 was irradiated with ultraviolet rays having an energy of 9 (l mJ/crA) using the same ultraviolet irradiation device as in Example 3.

The polymethyl methacrylate sheet subjected to the ultraviolet #fA F irradiation device obtained as described above was attached to the Chanzmar of the vacuum pre-deposition device, and Sn (manufactured by Furuuchi Chemical Co., Ltd.) was placed in three crucibles of the device. , 20φXIQimt
, purity 99.99%), 5nOx (manufactured by Furuuchi Chemical,
18φX 5 m*t% purity 99.99%), Ge
(manufactured by Furuuchi Chemical, 30φX10v+t, purity 99.9
99%), and while rotating this sheet at a speed of 3 Q rpm, Ge was first applied to the ultraviolet irradiated surface of the polymethyl methacrylate sheet using an electron beam evaporation method under vacuum conditions of 2 x 106 mm and 11 g. By evaporating Sn and SnO2 to a thickness of 40 mm, then co-evaporating Sn and SnO2 by irradiating electron beams from separate electron guns and co-evaporating while adjusting the total rate of Sn and SnO2, Sn was filled with Sn. By forming a composite layer on the Ge layer with a film thickness of 180 nm Sn fine particles in 5 nOz for 11 minutes at .8, and finally forming a Ge layer with a thickness of 40 nm on this composite layer again.
A disk-shaped optical recording medium having a recording layer with a thickness of 260 layers was manufactured.

When recording and reproducing the obtained disk-shaped optical recording medium under the same conditions as in Example 1, the minor axis was approximately 1 μm.
The laser beam intensity on the recording surface of the disk required to form a focal point was 6 mIQ, and the CN ratio was 57 dB.

In addition, when the disc-shaped optical recording medium recorded in Examples 1 to 6 was placed in a constant temperature and humidity layer at 60° C. and 95% R11, and a 120-port heat-and-moisture resistance test was conducted,
No change was observed in CN J, l:.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of the starter ti medium of the present invention. In each figure, 1 is a recording layer, 2 is an organic polymer layer, 3 is a substrate, and 4 is an energy beam irradiated surface of 2.

Claims (1)

[Scope of Claims] 1. A layer of an organic polymer 5 molecular weight substance irradiated with an energy beam, and a G
An optical recording medium consisting of a recording layer made of a ground metal or semiconductor and a metal oxide; 2. A patent in which the organic polymer is at least one type of polymethyl methacrylate, a copolymer containing methyl methacrylate as a main component, or a copolymer containing styrene as a main component. Claim 1: A recording medium containing personal information. 3. The metal or semiconductor is Sn, InXSb, Pb
, 81, Zn, CulAg, Au, and Ge. 4. The optical recording medium according to claim 1, wherein the metal oxide is at least one of Sn, Ins81, Zr, and Zn oxides. 5. The optical recording medium according to claim 1, wherein the recording layer is a composite layer in which fine particles of metal or semiconductor are dispersed in a thin film of metal oxide.