EP0353393B1
Expired / Lapsed
EP
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Optical information recording medium
Assignee: Taiyo Yuden Co Ltd
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Filing: 1989-04-17
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Granted: 1995-07-19
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Expires: 2009-04-17
Abstract
Abstract An optical information recording medium comprising a light transmitting substrate, a light absorptive layer overlaying the substrate to absorb a laser beam and a light reflective layer overlaying the light absorptive layer, wherein an optical parameter represented by rho = nabsdabs/ lambda where nabs is the real part of the complex refractive index of the light absorptive layer, dabs is the thickness of the light absorptive layer and lambda is the wavelength of a reading laser beam, is 0.05 </= rho </= 0.6, and the imaginary part kabs of the complex refractive index of the light absorptive layer is at most 0.3.
Inventors
- 👤 Emiko Hamada
- 👤 Yuji Arai
- 👤 Yuaki Shin
- 👤 Takashi Ishiguro
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 15:59
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/244; G11B7/246; G11B7/247; G11B7/2472; G11B7/004; G11B7/0045; G11B7/00452
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
An optical information recording medium comprising a light transmitting substrate, a light absorptive layer overlaying the substrate to absorb a laser beam and a light reflective layer overlaying the light absorptive layer, characterized in that an optical parameter represented by p =nabs d abs /λ where nabs is the real part of the complex refractive index of the light absorptive layer, dabs is the thickness of the light absorptive layer and λ is the wavelength of a reading laser beam, is 0,05 ≦ p < 0,6; and in that the imaginary part k abs of the complex refractive index of the light absorptive layer is at most 0,3.
Claim 2
Dependent Claim
108 words
An optical information recording medium comprising a light transmitting substrate, a light absorptive layer overlaying the substrate to absorb a laser beam and a light reflective layer overlaying the light absorptive layer, characterized in that an optical parameter represented by p =nabs d abs /λ where nabs is the real part of the complex refractive index of the light absorptive layer, dabs is the thickness of the light absorptive layer and λ is the wavelength of a reading laser beam, is 0,05 ≦ p < 0,6; and in that the imaginary part k abs of the complex refractive index of the light absorptive layer is at most 0,3.
Claim 3
Dependent Claim
29 words
The optical information recording medium according to Claim 1, wherein the light absorptive layer comprises a cyanine dye, and the light reflective layer is made of a metal film.
Claim 4
Dependent Claim
15 words
The optical information recording medium according to Claim 2, wherein the cyanine dye is indodicarbocyanine.
Claim 5
Dependent Claim
54 words
The optical information recording medium according to Claim 1, 2 or 3, wherein the light absorptive layer contains a material which, upon absorption of a laser beam by the light absorptive layer, undergoes a temperature rise and, at a temperature of from 100 to 600°C, undergoes an exothermic reaction with generation of a gas.
Claim 6
Dependent Claim
30 words
The optical information recording meduim according to any one of Claims 1 to 4, wherein nabs is n abs ≧ 1,8, and k abs is 0,001 ≦ k abs `0,3.
Claim 7
Dependent Claim
55 words
The optical information recording medium according to any one of Claims 1 to 5, wherein the real part nrf of the complex refractive index of the light reflective layer and the imaginary part krf of the complex refractive index of the light reflective layer satisfy a relation of k ref ≧ 2 nrf + 0,8.
Claim 8
Dependent Claim
41 words
The optical information recording medium according to any one of Claims 1 to 6, wherein an enhancing layer which is transparent to the wavelength of the reading laser beam is disposed between the light absorptive layer and the light reflective layer.
Claim 9
Dependent Claim
52 words
The optical information recording medium according to Claim 7, wherein an optical parameter represented by where nabs, dabs and λ are as defined above, n ehs is the real part of the complex refractive index of the enhacing layer and d ehs is the thickness of the enhacing layer, is 0,05 ≦ρ≦1,1.
Claim 10
Dependent Claim
39 words
The optical information recording medium according to any one of Claims 1 to 8, wherein the substrate is provided with a solvent resistant layer to protect the substrate from a solvent used for formation of the light absorptive layer.
References Cited (Backward Citations)
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