US5080945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Large-capacity-memory disk
Assignee: Daicel Corp
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Filing: 1991-02-19
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Granted: 1992-01-14
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Expires: 2011-02-19
Abstract
Abstract In a large capacity memory disk of the type in which data are read out by an optical system, the invention provides a large capacity memory disk characterized in that a methyl methacrylate copolymer consisting of 99 to 20 percent by weight methyl methacrylate and 1 to 80 percent by weight of a monomer copolymerizable with methyl methacrylate is used as the disk substrate.
Inventors
- 👤 Takeshi Moriwaki
- 👤 Shinji Tokuhara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:53
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/253; G11B7/26; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
103 words
In a high-density-data-recording disk comprising a transparent synthetic resin substrate made by injection molding and having means on one surface thereof for providing recorded data which can be read by a pick-up, the improvement which comprises: said substrate consists of a copolymer consisting essentially of 99 to 60 percent by weight of methyl methacrylate monomer units and 1 to 40 percent by weight of a styrene-containing comonomer, said copolymer having a number average molecular weight of from 10,000 to 500,000, a weight average molecular weight of from 20,000 to 2,000,000, and a melt flow rate of 20 g or less per 10 minutes.
Claim 2
Dependent Claim
103 words
In a high-density-data-recording disk comprising a transparent synthetic resin substrate made by injection molding and having means on one surface thereof for providing recorded data which can be read by a pick-up, the improvement which comprises: said substrate consists of a copolymer consisting essentially of 99 to 60 percent by weight of methyl methacrylate monomer units and 1 to 40 percent by weight of a styrene-containing comonomer, said copolymer having a number average molecular weight of from 10,000 to 500,000, a weight average molecular weight of from 20,000 to 2,000,000, and a melt flow rate of 20 g or less per 10 minutes.
Claim 3
Dependent Claim
37 words
A high-density-data-recording disk as claimed in claim 1, in which said copolymer consists essentially of not more than 97 weight percent of methyl methacrylate monomer units and at least 3 weight percent of units of said comonomer.
Claim 4
Dependent Claim
30 words
A high-density-data-recording disk as claimed in claim 1, in which said styrene-containing comonomer is selected from the group consisting of styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, o-chlorostyrene, p-chlorostyrene, 2,5-dichlorostyrene, m-bromostyrene and p-bromostyrene.
Claim 5
Dependent Claim
22 words
A high-density-data-recording disk as claimed in claim 1, in which the weight ratio of methyl methacrylate/styrene-containing comonomer is from 90/10 to 80/20.
Claim 6
Dependent Claim
81 words
In a high-density-data-recording disk, the improvement comprising said disk being manufactured by forming a copolymer of methyl methacrylate/styrene; injection-molding said copolymer in a molding machine having a stamper provided as a surface of the mold to form a molded disk; and vacuum depositing aluminum on a surface of the molded disk to form said high-density-data-recording disk, said copolymer having a weight ratio of methyl methacrylate/styrene of 60/40, a weight average molecular of 130,000 and a number average molecular weight of 35,000.
Claim 7
Dependent Claim
81 words
In a high-density-data-recording disk, the improvement comprising said disk being manufactured by forming a copolymer of methyl methacrylate/styrene; injection-molding said copolymer in a molding machine having a stamper provided as a surface of the mold to form a molded disk; and vacuum depositing aluminum on a surface of the molded disk to form said high-density-data-recording disk, said copolymer having a weight ratio of methyl methacrylate/styrene of 60/40, a weight average molecular of 130,000 and a number average molecular weight of 35,000.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-01-13 | 1995-07-15 | 1996-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-13 | 1999-07-15 | 2000-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-13 | 2003-07-15 | 2004-01-14 | $7700.00 | Window Closed / Lapsed |