EP0385341A2
Expired / Lapsed
EP
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Optical recording medium
Assignee: TDK Corp
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Filing: 1990-02-26
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Granted: —
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Expires: 2010-02-26
Abstract
Abstract An optical recording disk intended for use as an additionally recordable CD is provided. It has a substrate, a dye or recording layer on the substrate, and a reflective layer and a protective layer disposed on the recording layer in a close contact relationship. Recording is carried out by directing recording light to the recording layer to form a pit and reproduction is carried out by directing reproducing light to the pit. A layer containing a decomposition product of the dye or recording material, but substantially free of the substrate material is present at the interface between the substrate and the recording layer where the pit is formed.
Inventors
- 👤 Kenryo C/O Tdk Corporation Namba
- 👤 Masahiro C/O Tdk Corporation Shinkai
- 👤 Sinichi C/O Tdk Corporation Tezuka
- 👤 Tetsushi C/O Tdk Corporation Inoue
- 👤 Toshiki C/O Tdk Corporation Aoi
- 👤 Suguru C/O Tdk Corporation Takayama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:33
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/257; G11B7/2572; G11B7/242; G11B7/244; G11B7/246; G11B2007/24612; G11B7/2467; G11B7/247; G11B7/2472; G11B7/248; G11B7/249; G11B7/2492; G11B7/2495; G11B7/253; G11B7/2531; G11B7/2533; G11B7/2534; G11B7/2535; G11B7/258; G11B7/2595; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
106 words
In an optical recording medium comprising a substrate of a material, a recording layer of a dye-containing recording material on the substrate, and a reflective layer and a protective layer disposed on the recording layer in a close contact relationship, wherein recording is carried out by directing recording light to the recording layer to form a pit and reproduction is carried out by directing reproducing light to the pit, the improvement wherein a layer containing a decomposition product of the recording material, but substantially free of the substrate material is present at the interface between said substrate and said recording layer where the pit is formed.
Claim 2
Dependent Claim
106 words
In an optical recording medium comprising a substrate of a material, a recording layer of a dye-containing recording material on the substrate, and a reflective layer and a protective layer disposed on the recording layer in a close contact relationship, wherein recording is carried out by directing recording light to the recording layer to form a pit and reproduction is carried out by directing reproducing light to the pit, the improvement wherein a layer containing a decomposition product of the recording material, but substantially free of the substrate material is present at the interface between said substrate and said recording layer where the pit is formed.
Claim 3
Dependent Claim
27 words
The optical recording medium of claim 1 wherein a space is formed at the interface between the pit in the recording layer and the overlying reflective layer.
Claim 4
Dependent Claim
31 words
The optical recording medium of claim 1 wherein the recording layer has a coefficient of extinction k of from 0.03 to 0.25 at the wavelength of the recording and reproducing light.
Claim 5
Dependent Claim
31 words
The optical recording medium of claim 1 wherein the recording layer has an index of refraction n of from 1.8 to 4.0 at the wavelength of the recording and reproducing light.
Claim 6
Dependent Claim
27 words
The optical recording medium of claim 3 or 4 wherein the recording and reproducing light has a wavelength in the range of from 700 to 900 nm.
Claim 7
Dependent Claim
26 words
The optical recording medium of claim 4 wherein the recording layer has a thickness of 500 to 1,500 Å where the recording light is directed thereto.
Claim 8
Dependent Claim
65 words
The optical recording medium of claim 1 wherein an unrecorded portion of the recording layer where no pit is formed has a reflectivity of at least 60% and a recorded portion of the recording layer where pits are formed has a reflectivity of up to 40% of that of the unrecorded portion when the reproducing light is directed to the pit from the substrate side.
Claim 9
Dependent Claim
15 words
The optical recording medium of claim 1 wherein said recording layer is a coated layer.
Claim 10
Dependent Claim
15 words
The optical recording medium of claim 1 wherein said recording layer is a deposited layer.
Claim 11
Dependent Claim
16 words
The optical recording medium of claim 1 wherein the recording material contains at least two dyes.
Claim 12
Dependent Claim
19 words
The optical recording medium of claim 1 wherein said protective layer is formed by radiation curing a radiation-curable compound.
Claim 13
Dependent Claim
21 words
The optical recording medium of claim 11 wherein said protective layer has a pencil hardness of H to 8H at 25°C.
Claim 14
Dependent Claim
19 words
The optical recording medium of claim 11 wherein said protective layer has a thickness of at least 0.1 µm.
Claim 15
Dependent Claim
21 words
The optical recording medium of claim 1 wherein the substrate has an oxygen permeability of up to 5x10⁻¹⁰ cm³·cm⁻²·s⁻¹·(cmHg)⁻¹ at 25°C.
References Cited (Backward Citations)
No citation records indexed.
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