JPH10134415A - Optical recording medium capable of recording and reproduction and optical recording method - Google Patents

Abstract

(57) [Problem] To provide a recordable and reproducible optical recording medium having a metal thin film and an optical recording method. An optical recording medium is formed and deformable between a substrate, a metal thin film formed on the substrate, a reflection layer provided on the metal thin film, and the metal thin film and the reflection layer. A buffer layer 30 and a protective layer 50 on the reflective layer 40 for protecting the laminate are provided. Since the buffer layer 30 is used, recording is easy and compatibility with a conventional CD is possible. In addition, since it is not necessary to use an expensive organic dye, the manufacturing cost is reduced and the productivity is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recordable / reproducible optical recording medium and an optical recording method thereof, and more particularly to a recordable / reproducible compact disk (CD) having a metal or non-metallic recording layer and a method of optical recording on the medium. About.

[0002]

2. Description of the Related Art An optical recording medium has a smaller recording area per recording unit than an existing magnetic recording medium, and is therefore frequently used as a high-density recording medium. Such an optical recording medium has, depending on its function, a read-only system (Read Only Memory: ROM) that can only reproduce recorded information, and a write-once read-only system (Write Once Read Many: WO) that can be recorded only once.
RM) and an erasable method (E
(rasable Programmable Read Only Memory: EPROM)
Classified as Such an optical recording medium is required to have such characteristics that recorded information can be reproduced from a recording / reproducing device. For this reason, it is necessary to satisfy the existing standardization rules, and a reflectance of 70% or more and a CNR (Carriert
o Noise Ratio) is required.

In a recordable optical recording medium, recording is reproduced by a change in reflectivity due to a physical deformation of a recording layer before and after recording, a change in phase, a change in magnetic properties, and the like. In a recording medium compatible with a CD, in addition to the above-described high reflectance and CNR characteristics, long-term storage stability and high recording sensitivity are required. As described above, various optical recording media have been proposed using various materials in order to improve the characteristics of the optical recording media and easily manufacture the media, and some of them have been put to practical use.

According to JP-A-63-268142, as shown in FIG. 8, a recording medium comprises a substrate 1 on which a sensitizing layer 2 made of gelatin, casein, PVA or the like, and a C
It has a structure in which a metal thin film 3 of r, Ni, Au or the like is formed with a thickness of 50 to 500 angstroms. In the case of such a recording medium, at the time of optical recording using a laser beam, recording pits are formed by the metal thin film 3 absorbing light and the sensitizing layer 2 and the metal thin film 3 being deformed. However, since the recording pits are exposed on the medium having such a structure, it is difficult to store the recording for a long time.

According to US Pat. No. 4,973,520,
As shown in FIG. 9, a metal thin film 2 having a three-layer structure is formed on a substrate 1a.
A technique has been proposed in which a good recording characteristic of 50 dB or more can be obtained by forming a. However, recording pits are also formed on the metal thin film by laser irradiation, but the recording pits are exposed to the outside, so that the recording storability is poor.

In order to solve the above-mentioned drawbacks, US Pat. No. 4,983,440 discloses that, as shown in FIG. 10, a metal thin film 2b, 2b 'is formed on a substrate 1b as two recording layers 2a. In order to protect the recording layer 2a, a technique for forming a protective layer 4 thereon has been proposed. A recording medium according to this technology has a low reflectance of 20% or less due to the absence of a reflective layer, so that it cannot be used in an existing CD compatible type, and also has a high output to a drive in order to be practically used as an incompatible medium. There is a problem that it is necessary to use a light source of the type described above.

Further, according to US Pat. No. 5,039,558, as shown in FIG. 11, two substrates 1c, 1c 'in which metal thin films 2c, 2c' and protective layers 4c, 4c 'are laminated.
Is bonded by an adhesive layer 5 to improve the stability of the recording pit. However, in this method, since the metal thin film cannot simultaneously function as the reflection layer and the light absorption layer, the reflectance is in principle 70%.
There is less than a percent problem.

Further, according to US Pat. No. 5,328,813, a metal thin film is provided as a recording layer on a substrate, and a hard metal oxide layer is formed thereon to improve the recording preservation property and to increase the reflectivity to 40. ６０60%, but there is a problem of low CNR.

[0009]

On the other hand, U.S. Pat.
Nos. 90,388 and 5,155,723 disclose a technique of forming a recording layer with an organic dye layer 6 on a substrate 1d and forming a reflective layer 7 and a protective layer 4d thereon, as shown in FIG. Proposed. In this medium, the recording laser light is absorbed and generated by the dye layer 6 during recording, the substrate is deformed by heating, and information can be recognized by a change in reflectance of the deformed portion before and after recording.
% And a CNR after recording of 47 dB or more were made compatible with CD.

However, the recording layer of such a disk has a disadvantage in that heat resistance and light resistance are weak and an organic dye which is particularly expensive is used. In addition, the dye should be laminated on the substrate by spin coating in the state of being dissolved in an organic solvent. However, since the reflectance changes greatly due to the deviation of the thickness of the coating layer, the deviation of the coating layer is within ± 3%. However, expensive equipment capable of controlling the thickness is required, and there is a problem in that productivity is inferior due to precise thickness control.

Therefore, the present invention is compatible with a CD,
An object of the present invention is to provide an inexpensive and highly productive optical recording medium capable of recording / reproducing and an optical recording method thereof.

Another object of the present invention is to provide a recordable / reproducible optical recording medium having a high reflectivity and a recording signal, and having improved recording stability, and an optical recording method thereof.

[0013]

In order to solve the above-mentioned problems, an optical recording medium according to the present invention comprises a substrate having a guide groove, a metal thin film formed on the substrate, and a metal thin film formed on the metal thin film. A reflective layer provided, and a deformable buffer layer formed between the metal thin film and the reflective layer.

Further, the optical recording method for an optical medium of the present invention comprises:
An optical recording method for an optical recording medium that forms pits where deformation occurs, a step of forming a metal thin film on a substrate having a predetermined groove formed in advance, and a step of forming a buffer layer on the metal thin film. Heating the metal thin film located between the substrate and the buffer layer with a laser beam so that at least one of the substrate, the metal thin film, and the buffer layer is deformed. Here, the pit means a portion deformed by the laser beam. Optically recordable / readable pits generally include all types of optically recordable and searchable indicia. The deformed portions of the substrate, the metal thin film, and the buffer layer have optically different characteristics from the remaining portions.

The method of optically recording on a metal thin film further includes a step of directly heating the buffer layer by the laser beam, the method including a dye capable of absorbing the thermal energy of the laser beam applied to the buffer layer. It is desirable that a groove for guiding light is formed on the substrate during recording in the metal film.

Also, the k value of the imaginary part of the birefringence coefficient is 0.
01 or more metals as a raw material of the metal thin film, the thickness of the metal thin film is in the range of 30 to 500 Å, particularly, Au, Al, Ag, Pt, Cu, Cr, Ni, Ti, Ta, Fe and alloys thereof It is desirable that it be made of at least one selected from the following.

The thickness of the buffer layer is in the range of 50 to 10000 angstroms, and its glass transition temperature is 60.
It is desirable to be in the range of 180 to 180 ° C. Further, in order to improve the characteristics, an organic dye is added to the organic material of the buffer layer.
% Can be added. The reflective layer is made of Au, Al, A
It is desirable that it be made of at least one selected from g, Pt, Cu, Cr, Ni, Ti, Ta, Fe and alloys thereof.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing a laminated structure of a disk which is an embodiment of the optical recording medium of the present invention. As shown in FIG. 1, at the time of recording, a metal thin film 20 is formed on a substrate 10 in which a groove for guiding light is formed, and a buffer layer 30 and a reflective layer 40 are sequentially laminated. The protective layer 50 is selectively disposed on the reflective layer 40 to protect the recording medium.

In the present invention, during optical recording, the focused laser beam heats the metal thin film 20, and this heat is
0 and the portion of the substrate 10 adjacent to the heated portion of the metal thin film 20 is also thermally expanded and deformed to form pits. Inflates towards. At the time of recording / reproducing, the reflectance of a part of the substrate 10 on which the recording is performed and the deformed part of the metal thin film 20 are lower than those of the unrecorded part according to the following principle.

First, the reflectance decreases due to the disappearing interference between the reflected light from the interface between the substrate 10 and the metal thin film 20 and the reflected light from the interface between the buffer layer 30 and the reflective layer 40. FIG. 2 shows a structure of a pit which is a recording portion formed on the disk.
As shown in FIG. 2, the thickness of the buffer layer 30 is initially determined at d ₁ so that the reflected light b ₁ from the reflective layer 40 and the reflected light c from the metal thin film 20 cause reinforcing interference. Have been. The substrate 10 and the metal thin film 20 are thermally expanded by heating, so that the buffer layer 30 becomes as thin as d _2, and the expansion of the buffer layer 30 deforms the reflective layer 40. Accordingly, the reflectance is decreased by destructive interference between the reflected light b ₂ from the interface between the buffer layer 30 and the reflected light a is reflected at the interface between the substrate 10 and the metal thin film 20 and the reflective layer 40.

This utilizes the Fabry-Perot effect, and as shown in FIG. 3, the reflectance of the recording medium changes depending on the thickness of the buffer layer 30. Therefore, the buffer layer 30
Should be formed of a material that can be deformed to a thickness d ₂ under conditions that cause annihilation interference due to deformation of the metal thin film 20.

Second, the reflectance is reduced due to the dispersion of the incident light at the recording site. Substrate 10, metal thin film 20, and buffer layer 3
2 is deformed as shown in FIG. 2, and in particular, there are inclined surfaces on both sides of the recording portion, the recording light is dispersed on the wall surface of the metal thin film 20, and the reflectance is lower than that of the unrecorded portion where the incident light is not dispersed. descend. For this reason, the recorded portion has a lower reflectance than the unrecorded portion, and recording can be reproduced by the difference between the reflectances of the recorded portion and the unrecorded portion.

Third, the recording light is irradiated to the metal thin film 20.
Absorbs light, and when the absorption site is locally heated and the temperature rises sharply, the metal thin film 20 and the adjacent substrate 10
A buffer layer 30 is locally thermally decomposed, as shown in FIG. 2, the overall reflectance by reflected light a and b ₂ is smaller drops. FIG. 6 shows an antiferromagnetic magnetic resonance image on the deformed substrate 10 and the metal thin film 20 after removing the upper layer, and FIG. 7 shows an antiferromagnetic magnetic resonance image on the deformed buffer layer 30 after removing the reflective layer 40. Shown in

[0024] As described above, the disk is an optical storage medium of this embodiment is reflected from the reflected light b ₁ and the metal thin film to be reflected from the reflective layer 40 and the reflective layer 40 formed on the buffer layer 30 By adjusting the thickness of the buffer layer 30 so as to reinforce the light c, 70% or more reflection at an unrecorded portion becomes possible. In particular, a dye is added to the buffer layer 30 as needed to adjust the refractive index of the buffer layer 30 to maximize the Fabry-Perot effect.

In the disk of the present embodiment as described above, the substrate 10 is transparent to the laser beam,
It can be manufactured using materials such as polycarbonate, polymethyl-methacrylate, epoxy, polyester, and amorphous polyolefin that have excellent impact strength and can be expanded and deformed by heat. The glass transition temperature for thermal deformation of the substrate 10 is in the range of 80 to 200C, and the optimal temperature is 100 to 200C. On the surface of the substrate 10,
Depth of 30 for guiding laser beam when recording / reproducing information
It is necessary to form a groove having a thickness of about 450 nm and a width of 0.1 to 1.2 μm.

The metal thin film 20 should function as a heat generating layer that absorbs the recording laser beam to generate heat and a partial mirror for indicating the contrast before and after recording. Rate characteristics are required. Thickness is 30-500 Å, transmittance is 5
The appropriate absorption rate is 5 to 95%. Furthermore, instead of the metal thin film layer 20, a non-metal film can be applied as the thin film / partial reflection film 20. As the non-metallic thin film recording layer, a non-metallic film such as silicon and its compound (silicon nitride, silicon germanium, silica, SiO, etc.) can also be used.

The k value of the imaginary part of the complex refractive index of the optical property of the substance forming the metal or non-metal thin film recording layer is suitably 0.01 or more. In addition, the deformation of the recording portion is small, and the recording sensitivity is also small. As a result of the computer simulation, 7.15 + 3.93i, 7.15 + 5.85i,
8.96 + 6.28i, 9.56 + 5.90i, 8.1
Materials for a metal or non-metallic thin film having a k value within a pentagon determined by the vertex of 4 + 3.77i include:
It has been found that it does not provide effective recording sensitivity for the desired recordable CD.

On the other hand, when the thickness of the metal thin film 20 is 500 Å or more, the recording signal becomes small for the following reasons. First, the expansion of the substrate 10 at the time of recording is obstructed by the metal thin film 20, and the deformation of the recording portion is reduced. Second, as shown in FIG. 4, as the thickness of the metal thin film 20 increases, the decrease in reflectance due to a change in the thickness of the buffer layer 30 during recording decreases, and the contrast of the recording portion decreases. . On the other hand, when the thickness of the metal thin film 20 is 30 Å or less, the amount of heat generated by absorption at the time of recording becomes small, and it becomes difficult to deform the substrate.

The thermal conductivity of the metal thin film 20 is 4 W /
cm ° C or higher, when recording and heating with a laser beam,
Heat cannot be concentrated in the heated thin film and is quickly transmitted to the surroundings, making it difficult to heat above the required temperature, and even if heated, the size of the recording part may be expanded and extended to adjacent tracks. The thermal conductivity of the metal thin film should be set to 4 W / cm ° C. or less.

The coefficient of linear expansion of the metal thin film 20 is 3 × 10 −6.
/ ° C. or more is appropriate, and if it is less than or equal to 1, the metal thin film 20 is cracked by expansion due to deformation of the substrate 10 during recording,
A uniform recording signal value cannot be obtained.

As the raw materials of the metal thin film requiring the above conditions, Au, Al, Ag, Pt, Cu, Cr, Ni, Ti, Ta,
At least one metal is selected and applied from the group consisting of Fe and its alloys, and this metal thin film 20
Are laminated on the substrate 10 by vacuum evaporation, electron beam, sputtering, or the like.

The buffer layer 30 is preferably a layer which absorbs deformation of the substrate 10 and the metal thin film 20 and is easily deformed and formed of an appropriate fluid organic material. This buffer layer 30
The glass transition temperature is suitably in the range of 60 to 180 ° C. and needs to be lower than the glass transition temperature of the substrate used. Here, the buffer layer 3
If the glass transition temperature of 0 is 60 ° C. or lower, the storage stability of the recording decreases, and if it is 180 ° C. or higher, the deformation of the substrate 10 is hindered, and the recording sensitivity decreases. Such a buffer layer 30 is coated by a spin coating method by dissolving an organic substance in an organic solvent. It is desirable to use a solvent having good solubility of the organic substance and not damaging the substrate. As shown in FIG. 4, the thickness of the buffer layer 30 is set so as to have a reflectance of 70% or more, and the range is suitably 50 to 10000 angstroms.

Organic materials used as the material of the buffer layer 30 include vinyl alcohol-based resin, vinyl acetate-based resin, acrylate-based resin, polyester-based resin, polyether-based resin, polystyrene-based resin, urethane-based resin, and cellulose-based resin. There are resins, fattic acid compounds, low molecular weight organic compounds, and the like. Copolymers of these materials and the like can also be used as a raw material of the buffer layer.

In order to facilitate thermal deformation of the substrate during recording, a dye can be added to the buffer layer 30. When a dye is added, the buffer layer 30 is also heated during recording, and the substrate 10 is easily deformed. The amount of the dye to be added should be less than 30 wt% of the material of the buffer layer, and if it is more than that, a high reflectance cannot be obtained. The dye that absorbs light used during recording is selected according to the wavelength length of the recording laser beam (long wavelength: low-density optical disk, low wavelength: high-density optical disk). It is desirable to use near-infrared dyes that absorb wavelengths in the 780-850 nm range or dyes that absorb wavelengths in the 610-700 nm range. For example, cyanine, croconium, phthalocyanine, naphthalocyanine and the like are used.

The reflection layer 40 is formed by vacuum evaporation, electron beam evaporation,
It can be formed by a sputtering method or the like, and its raw materials are Au, Al, Ag, Pt, Cu, Cr, Ni, Ti, Ta,
Fe and its alloys are used, and the thickness is 500-150
A range of 0 Angstroms is appropriate.

As the protective film 50 for protecting the recording medium, a material having a strong impact strength and being transparent and curable by ultraviolet rays (UV) can be used, and an epoxy-based or acrylate-based cured resin is formed by spin coating. After being coated, it is cured by ultraviolet rays and used as a protective film.

In this embodiment, an example in which each layer (substrate, metal thin film, buffer layer, reflection layer) is deformed has been described. However, the power and physical characteristics (for example,
Young's modulus, thermal conductivity, coefficient of thermal expansion, glass transition temperature, etc.)
Thereby, only one or two layers can be deformed. Since the melting point of the metal thin film is high, the deformation of the metal thin film itself is rare. However, thermal deformation of the metal thin film occurs due to the power of the laser beam. For example, when the power of the recording laser beam is high, the metal thin film 20 is melted by heating at a temperature higher than the metal melting point in order to form around the center of the condensing light.

Further, when the raw material used for the buffer layer 30 has more stable physical properties (for example, a lower coefficient of thermal expansion, a higher glass transition temperature, and a higher Young's modulus) than the raw material used for the substrate 10. , Only the substrate 10 is deformed.
During laser recording, the metal thin film 20 and the buffer layer 30 are deformed due to thermal transition of the metal thin film 20. However, the metal thin film 2
0 and the deformation at the buffer layer 30 are very weak, so it is difficult to observe. Also, this deformation has little effect during recording.

When the material used for the substrate 10 has more stable physical properties than the material used for the buffer layer 30, the deformation mainly occurs in the buffer layer 30. When the material used for the substrate 10 and the material used for the buffer layer 30 have similar physical properties,
At 0, deformation occurs mainly.

[0040]

EXAMPLES The present invention will be described in more detail based on examples, but the present invention is not limited to the detailed experimental examples.

A first embodiment of the present invention will be described.
Depth 170 nm, width 0.05 μm, track pitch 1.
A 10 nm Al thin film was vacuum deposited on a 1.2 mm thick polycarbonate substrate having 6 μm grooves. On top of this, a coating solution of 0.9 g of cyanobiphenyl epoxyamine dissolved in 10 ml of diacetone alcohol was spin-coated at 2000 rpm to form a buffer layer. At this time, the thickness of the buffer layer at the groove was measured by SEM and found to be about 2500 angstroms. Then, after drying in a vacuum oven maintained at a temperature of 40 ° C. for about 4 hours, 1000 Å of Al was vacuum deposited to form a reflective layer. On top of this, epoxy acrylate
After spin-coating the UV-curable resin, it was cured to produce a disk.

The disk manufactured in this way was 780 nm thick.
As a result of evaluation using an evaluation device using a laser beam, the reflectance was 72%, and the recording speed was 1.3 m / se.
c, After recording a 720 kHz signal with a recording power of 8 mW, the recording was reproduced with a 0.7 mW laser beam to obtain a 51 dB C
NR was obtained. When reproduced after recording at a recording speed of 4.8 m / sec and a recording power of 10 mW, a CNR of 42 dB was obtained.
I got When the recording power is changed under the above recording conditions,
As shown in FIG. 5, it is possible to reproduce a recording signal of 47 dB or more at 4 mW or more. This disk is pioneer RP
After recording audio with a -1000CD recorder,
It was reproducible on a D player, and the recording characteristics were evaluated using CD-CATS. As a result, all items satisfied the CD standard.

Next, as the second and third embodiments, discs were manufactured by the same method as in the first embodiment except that the thickness of the Al thin film was 7 nm and 12 nm. Then, as a result of recording evaluation under the evaluation conditions as in the first embodiment,
Disk with 7nm metal thin film has reflectance 73%, CNR 48dB
Shows that a disk with a metal thin film of 12 nm has a reflectance of 69%,
A CNR of 53 dB was shown.

Further, as the fourth to eighth embodiments, the metal thin film was made of Au, Cu, Ag, Ni, and Pt as shown in Table 1 below, and disks were manufactured and evaluated in the same manner as in the first embodiment. did. Table 1 shows the evaluation results.

[0045]

[Table 1]

Further, as ninth to thirteenth embodiments,
The material of the buffer layer was PMMA (Polyscience, Mw: 2500).
0), PVA (Polyscience: 35000), Polyethyle
neoxide (Polyscience, Mw: 32000) and fatty acid (Fatty acid, Tokyo Kasei, Standard kit FE)
M-1), the thickness of the buffer layer was adjusted with a groove so as to be 2500 angstroms, and the same recording evaluation as in the second example was performed. Table 2 shows the evaluation results.

[0047]

[Table 2]

As a fourteenth embodiment, when the buffer layer is formed, NK125 (Nippon Kogaku Dye) is added to the buffer layer in an amount of 0.5 wt% of the material of the buffer layer. A disc was produced in the same manner as described above. This disc was recorded at a recording speed of 1.3 m / sec and a recording power of 8 mw.
In the case of recording at, the CNR of 52 dB was obtained at 4.8 m / sec, and the CNR of 48 dB was obtained.
It could be used as a D-ROM disk.

[0049]

As described in detail above, according to the present invention, recording can be performed by using a buffer layer, and compatibility with a CD becomes possible. In particular, since expensive organic dyes are not used, manufacturing costs can be reduced, and productivity can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a laminated structure of a disk which is an optical recording medium according to the present invention.

FIG. 2 is a schematic sectional view showing a structure of a pit which is a recording portion formed on a disk according to the present invention.

FIG. 3 is a graph showing a change in reflectance according to a change in thickness of a buffer layer with respect to a change in thickness of a metal thin film of a disk according to the present invention.

FIG. 4 is a graph showing a change in reflectance according to a change in the thickness of a buffer layer in the disk according to the present invention.

FIG. 5 is a graph showing the relationship between the recording power and the CNR of the disk of the first embodiment according to the present invention.

FIG. 6 is an antiferromagnetic magnetic resonance image showing a substrate and a metal thin film deformed by a recording unit.

FIG. 7 is an antiferromagnetic magnetic resonance image showing a buffer layer deformed by a recording unit.

FIG. 8 is a sectional view showing a laminated structure of a conventional optical recording medium.

FIG. 9 is a sectional view showing a laminated structure of a conventional optical recording medium.

FIG. 10 is a sectional view showing a laminated structure of a conventional optical recording medium.

FIG. 11 is a sectional view showing a laminated structure of a conventional optical recording medium.

FIG. 12 is a sectional view showing a laminated structure of a conventional optical recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Substrate 20 ... Metal thin film 30 ... Buffer layer 40 ... Reflective layer 50 ... Protective layer

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 21, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Third, the recording light is irradiated to the metal thin film 20.
Absorbs light, and when the absorption site is locally heated and the temperature rises sharply, the metal thin film 20 and the adjacent substrate 10
A buffer layer 30 is locally thermally decomposed, as shown in FIG. 2, the overall reflectance by reflected light a and b ₂ is smaller drops. FIG. 6 shows an AFM photograph on the deformed substrate 10 and the metal thin film 20 after removing the upper layer, and FIG. 7 shows an AFM photograph on the deformed buffer layer 30 after removing the reflective layer 40.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6 shows a substrate and a metal thin film deformed by a recording unit.
It is an AFM photograph .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7
4 is an AFM photograph showing a buffer layer deformed by a recording unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number 96-57073 (32) Priority date November 25, 1996 (33) Priority claim country South Korea (KR) (31) Priority claim number Japanese Patent Application No. 8 −235693 (32) Priority Date Hei 8 (1996) September 6 (33) Priority Country Japan (JP) (72) Inventor Min Kyung ▲ Rotation ▼ Republic of Korea 1 16 No.-2 (72) Inventor Kim Jong-seong South Korea Gyeonggi-do Seongnam-si, Bundang-gu, Jinya-dong 177 Jongsol-Maul, Ritsuko-Apart 101 Building No. 1604 No. 1604 (72) Inventor Galit Cornelis Dabeldam Netherlands 6904 Na Simbar 16 (72) Inventor Freddie Garhard Hendricks Van Wick The Netherlands 6814 BK Ahn Hem Apeldonwe 24 (72) inventor Nico Masukanto Netherlands 6852 E. N. Haise down + 3

Claims (26)

[Claims] A substrate having a guide groove formed thereon, a metal thin film formed on the substrate, a reflective layer provided on the metal thin film, and formed between the metal thin film and the reflective layer. An optical recording medium capable of recording and reproduction, comprising: a deformable buffer layer. 2. The optical recording medium according to claim 1, further comprising a protective layer provided on said reflective layer. 3. The optical recording medium according to claim 1, wherein at least one of the substrate, the metal thin film, and the buffer layer has a deformed portion. 4. The optical recording medium according to claim 1, wherein said buffer layer is made of an organic material. 5. The optical recording medium according to claim 1, wherein the substrate and the metal thin film have a deformed portion, and the buffer layer has a reduced thickness at the deformed portion. 6. The semiconductor device according to claim 1, wherein the substrate, the metal thin film, the buffer layer, and the reflection layer have a deformed portion.
An optical recording medium capable of recording and reproduction according to the above. 7. The optical recording medium according to claim 1, wherein the metal thin film has an imaginary part of a complex refractive index coefficient of 0.01 or more. 8. The optical recording medium according to claim 1, wherein the thickness of said thin metal film is in the range of 30 to 500 Å. 9. The metal thin film is made of Au, Al, Ag, Pt, Cu, C
2. The method according to claim 1, comprising at least one selected from r, Ni, Ti, Ta, Fe and alloys thereof.
An optical recording medium capable of recording and reproducing according to claim 8. 10. The buffer layer has a thickness of 50 to 10,000.
2. The recordable and reproducible optical recording medium according to claim 1, wherein the optical recording medium is in the range of angstrom. 11. The buffer layer has a glass transition temperature of 60 to 60.
5. The recordable and readable optical recording medium according to claim 4, wherein the temperature is in a range of 180.degree. 12. The optical recording medium according to claim 1, wherein the buffer layer contains less than 30% of an organic dye. 13. The reflection layer is made of Au, Al, Ag, Pt, Cu, C
2. The method according to claim 1, comprising at least one selected from r, Ni, Ti, Ta, Fe and alloys thereof.
An optical recording medium capable of recording and reproduction according to the above. 14. The optical recording medium according to claim 1, wherein the metal thin film has a thermal conductivity of 4 W / cm ° C. or less. 15. An optical recording method on an optical recording medium for forming pits in which deformation occurs, comprising: forming a metal thin film on a substrate having a predetermined groove formed in advance; Forming a layer, at least one of the substrate, the metal thin film and the buffer layer
Heating the metal thin film located between the substrate and the buffer layer with a laser beam so that more than one deformation occurs. 16. The method according to claim 15, wherein the step of heating the metal thin film with a laser beam further includes the step of deforming the buffer layer, the metal thin film, and the substrate.
An optical recording method for the optical recording medium according to the above. 17. The optical recording method on an optical recording medium according to claim 15, further comprising a step of forming a reflective layer on the buffer layer. 18. The method according to claim 17, further comprising a step of forming a protective layer on the reflective layer. 19. The optical recording method according to claim 15, wherein the buffer layer is made of an organic material. 20. The metal thin film is made of Au, Al, Ag, Pt, Cu,
16. The optical recording method according to claim 15, wherein the optical recording medium is made of at least one selected from the group consisting of Cr, Ni, Ti, Ta, Fe, and alloys thereof. 21. The glass transition temperature of the buffer layer is 60 to
The optical recording method according to claim 15, wherein the temperature is in a range of 180 ° C. 22. The optical recording method according to claim 15, further comprising a step of adding an organic dye to the buffer layer. 23. The optical recording method on an optical recording medium according to claim 15, wherein the buffer layer contains an organic dye of less than 30%. 24. The optical recording method on an optical recording medium according to claim 15, wherein said metal thin film has a thermal conductivity of 4 W / cm ° C. or less. 25. The optical recording method according to claim 15, wherein the step of heating the metal thin film with a laser beam further comprises a step of deforming the buffer layer. 26. The method according to claim 17, further comprising the step of deforming the reflection layer on the buffer layer.