Patent EP0235812A1 successfully refreshed from Google Patents.
EP0235812A1
Expired / Lapsed
EP
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Optical disk
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1987-03-04
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Granted: —
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Expires: 2007-03-04
Abstract
Abstract An optical disk is provided which comprises two sheets of substrates; (1) or two sheets of substrate (1) and a reinforcing plate (4) or a reinforcing rim; or one sheet of substrate (1) and a reinforcing plate; (4) which are bonded to form an integrated body having a spacer (3) interposed there-between, said spacer (3) being made of elastomeric foam having a specific gravity of not more than 1.5 and an expansion ratio of not less than 1.5 as the material of the said spacer.(3)
Inventors
- 👤 Tsutomu Fujita
- 👤 Yoshiaki Togawa
- 👤 Seimei Yasui
- 👤 Toshitsugu Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 22:28
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
70 words
An optical disk comprising two sheets of substrates; or two sheets of substrate and a reinforcing plate or a reinforcing rim; or one sheet of substrate and a reinforcing plate; which are bonded to form an integrated body having a spacer interposed therebetween, said spacer being made of an elastomeric foam material having a specific gravity of not more than 1.5 and an expansion ratio of not less than 1.5.
Claim 2
Dependent Claim
70 words
An optical disk comprising two sheets of substrates; or two sheets of substrate and a reinforcing plate or a reinforcing rim; or one sheet of substrate and a reinforcing plate; which are bonded to form an integrated body having a spacer interposed therebetween, said spacer being made of an elastomeric foam material having a specific gravity of not more than 1.5 and an expansion ratio of not less than 1.5.
Claim 3
Dependent Claim
39 words
2 An optical disk according to Claim 1, wherein said elastomeric foam material is made from an elastomer having a glass transition temperature of not more than 30°C and a reversible elastic region of strain of 1 to 2000%.
Claim 4
Dependent Claim
31 words
An optical disk according to Claim 2, wherein said elastomer has a glass transition temperature of not more than 0°C and a reversible elastic region of strain of 100 to 1000%.
Claim 5
Dependent Claim
20 words
An optical disk according to Claim 1, wherein said elastomeric foam material has an expansion ratio of 1.5 to 15.
Claim 6
Dependent Claim
20 words
An optical disk according to Claim 1, wherein said elastomeric foam material has an expansion ratio of 3 to 10.
Claim 7
Dependent Claim
28 words
An optical disk according to Claims 1, 2, 3, 4 or 5, wherein said spacers are disposed at the inner and outer periphery parts of the optical disk.
References Cited (Backward Citations)
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