Patent EP0210405A2 successfully refreshed from Google Patents.
EP0210405A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
High-density information recording carrier
Assignee: Daicel Corp
•
Filing: 1986-06-18
•
Granted: —
•
Expires: 2006-06-18
Abstract
Abstract A high-density information recording carrier such as an optical disk which is used for recording and/or playing back information carried on a plastic substrate by means of laser beams has an improved protective layer between a recording layer and the plastic substrate. The protective layer is made of inorganic glass made of alkali-free glass containing less than 1 wt % of alkali metal oxides. The resulting optical disk shows improved durability, higher C/N, lower BER and higher film forming rate.
Inventors
- 👤 Masaru Sato
- 👤 Nagayoshi Tsukane
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 16:04
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/257; G11B7/2578; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24306; G11B2007/25705; G11B2007/25706; G11B2007/25708; G11B2007/2571; G11B2007/25715; G11B7/253; G11B7/2533; G11B7/2534; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
67 words
(1) A high-density information recording carrier including a transparent plastic substrate, a high-density information recording layer formed on the substrate, and a thin film layer of inorganic glass interposed between the substrate and the recording layer, characterized in that said thin film layer of inorganic glass is made of alkali-free glass which contains less than . 1 wt% of alkali metals in terms of alkali metal oxides.
Claim 2
Dependent Claim
30 words
(2) A high-density information recording carrier as set forth in claim 1, wherein the amount of said alkali metals is less than 0.8 wt% in terms of alkali metal oxides.
Claim 3
Dependent Claim
37 words
(3) A high-density information recording carrier as set forth in claim 1 or 2, wherein the inorganic glass contain further from 20 wt% to 35 wt% of alkali earth metals in terms of alkaline earth metal oxides.
Claim 4
Dependent Claim
35 words
(4) A high-density information recording carrier as set forth in claim 3, wherein said alkaline earth metal oxide is at least one of compounds selected from a group comprising BaO, CaO, MgO, Sr0 and BeO.
Claim 5
Dependent Claim
36 words
(5) A high-density information recording carrier as set forth in any one of claims 1 to 4, wherein the inorganic glass further have a coefficient of linear expansion of 40 to 70 x 10 -7 /°C.
Claim 6
Dependent Claim
63 words
(6) A high-density information recording carrier including a transparent plastic substrate and a high-density recording layer formed thereon with a thin film layer of inorganic glass interposed between them, characterized in that said thin film layer of inorganic glass is made of inorganic glass which contain from 20 wt% to 35 wt% of alkaline earth metals in terms of alkaline earth metal oxides.
Claim 7
Dependent Claim
62 words
(7) A high-density information recording carrier of the type having a transparent plastic substrate and a high-density information recording layer formed thereon with a thin film layer of inorganic glass interposed between them, characterized in that said thin film layer of inorganic glass is made of inorganic glass having a coefficient of linear expansion of 40 to 70 x 10 -7 /°C.
Claim 8
Dependent Claim
28 words
(8) A high-density information recording carrier as set forth in any one of claims to 7, wherein said high-density information recording layer is made of magneto-optical recording material.
Claim 9
Dependent Claim
28 words
(9) A high-density information recording carrier as set forth in claim 8, wherein said magneto-optical recording material is amorphous alloy composed of rare earth elements and transition metals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.