US4784447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Holographic objective mirror for optical storage
Assignee: International Business Machines Corp
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Filing: 1987-03-13
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Granted: 1988-11-15
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Expires: 2007-03-13
Abstract
Abstract A holographic mirror is used in an optical storage head to diffract a laser beam perpendicularly to the optical medium and also to focus the beam onto the optical medium. The mirror can also function to cause circularization of a collimated laser beam of elliptical cross-section.
Inventors
- 👤 Milton R. Latta
- 👤 Timothy C. Strand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:39
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1362; G11B7/08; G11B7/085; G11B7/08547
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
73 words
A device for focusing a laser beam onto a track-containing optical storage medium, said device comprising means for directing the laser beam, in a direction tangential to the track direction on the optical medium, to a holographic mirror which diffracts the laser beam perpendicularly to the optical medium and also focuses the beam onto the optical medium, with the maximum perpendicular height of the holographic mirror above the optical medium being 5 mm.
Claim 2
Independent Claim
73 words
A device for focusing a laser beam onto a track-containing optical storage medium, said device comprising means for directing the laser beam, in a direction tangential to the track direction on the optical medium, to a holographic mirror which diffracts the laser beam perpendicularly to the optical medium and also focuses the beam onto the optical medium, with the maximum perpendicular height of the holographic mirror above the optical medium being 5 mm.
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) | 1991-11-15 | 1992-05-16 | 1992-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-15 | 1996-05-16 | 1996-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-15 | 2000-05-16 | 2000-11-15 | $7700.00 | Window Closed / Lapsed |