Patent US5392271A successfully refreshed from Google Patents.
US5392271A
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Concurrent recording and reproducing optical disc and optical head apparatus for the same
Assignee: NEC Corp
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Filing: 1993-06-28
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Granted: 1995-02-21
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Expires: 2013-06-28
Abstract
Abstract A concurrent recording and reproducing optical disc has a magneto-optical medium film coated on a ROM disc having rows of pits. The magneto-optical film is arranged by a predetermined interval between the two adjacent rows of the pit rows. The predetermined interval is determined by a dark Airy disc circle band of a beam spot obtained by focusing a light beam on the concurrent recording and reproducing optical disc. Preferably, two light beams are focused on the optical disc to provide first and second beam spots. The first beam spot is focused on one of the pit rows, and the second beam spot is focused on an area between two selected pit rows.
Inventors
- 👤 Tsutomu Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:08
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10595; G11B11/10597; G11B11/10532; G11B11/10541; G11B11/10543; G11B13/00; G11B13/04; G11B13/045
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
91 words
A concurrent recording and reproducing optical disc, comprising: a disc substrate having rows of pits thereon, said rows of pits storing read only memory information; and a magneto-optical medium film deposited on said disc substrate, said magneto-optical medium film storing programmable and erasable information; wherein said magneto-optical medium film is arranged by a predetermined interval between each two adjacent rows of said rows of pits, said predetermined interval being dependent on a diameter of a dark Airy disc circle band of a light beam spot focused on said magneto-optical medium film.
Claim 2
Dependent Claim
91 words
A concurrent recording and reproducing optical disc, comprising: a disc substrate having rows of pits thereon, said rows of pits storing read only memory information; and a magneto-optical medium film deposited on said disc substrate, said magneto-optical medium film storing programmable and erasable information; wherein said magneto-optical medium film is arranged by a predetermined interval between each two adjacent rows of said rows of pits, said predetermined interval being dependent on a diameter of a dark Airy disc circle band of a light beam spot focused on said magneto-optical medium film.
Claim 3
Dependent Claim
123 words
An optical head apparatus for a concurrent recording and reproducing optical disc, comprising: a light source for providing two light beams; means for propagating said two light beams to be focused on the concurrent recording and reproducing optical disc by first and second beam spots, said first beam spot being focused on one of rows of pits provided on said concurrent recording and reproducing optical disc, and said second beam spot being focused on an area between selected two rows of said rows of said pits, said concurrent recording and reproducing disc being coated with a magneto-optical medium film; and means for processing light beams reflected from the concurrent recording and reproducing optical disc in accordance with said first and second beam spots.
Claim 4
Dependent Claim
123 words
An optical head apparatus for a concurrent recording and reproducing optical disc, comprising: a light source for providing two light beams; means for propagating said two light beams to be focused on the concurrent recording and reproducing optical disc by first and second beam spots, said first beam spot being focused on one of rows of pits provided on said concurrent recording and reproducing optical disc, and said second beam spot being focused on an area between selected two rows of said rows of said pits, said concurrent recording and reproducing disc being coated with a magneto-optical medium film; and means for processing light beams reflected from the concurrent recording and reproducing optical disc in accordance with said first and second beam spots.
Claim 5
Dependent Claim
46 words
An optical head apparatus for a concurrent recording and reproducing optical disc, according to claim 2, wherein: said propagating means comprises a diffraction grating for diffracting said two light beams to be divided as six light beams focused on said concurrent recording and reproducing optical disc.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-20 | 1998-08-22 | 1999-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-20 | 2002-08-22 | 2003-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-20 | 2006-08-22 | 2007-02-21 | $7700.00 | Window Closed / Lapsed |