Disk unit with retaining ring
US4482903A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 20, 1983 |
| Grant date | Nov 13, 1984 |
| Priority date | — |
| Expiry date | Jun 20, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B17/32
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This disclosure relates to an optical disk unit with two states in which the web assembly is in different circumferentially-symmetric tensions. One tension is sufficiently great to provide the desired degree of planarity when used with write/read apparatus. The other tension is significantly reduced, keeping the web assembly materials well below their elastic limits to reduce tension and prolong product life. The optical disk unit includes a flexible disk-shaped web assembly including a support web and preferably an opposed cover sheet. An annular retaining ring engages the web assembly around its periphery. The support web carries a record layer with an information storage region. The annular retaining ring includes selectively operable means for changing the state of the disk unit to adjust the web assembly tension between the two tensions. In one embodiment, the state-changing means includes a bi-stable spring having a stable condition for each of the two web assembly tensions. In its high-tension state, the spring bears against the web assembly, deforming the web assembly to increase its tension.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.