EP0281756A2
Expired / Lapsed
EP
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Holographic objective mirrors for optical storage
Assignee: International Business Machines Corp
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Filing: 1988-02-02
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Granted: —
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Expires: 2008-02-02
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 circularisation of a collimated laser beam of elliptical cross-section.
Inventors
- 👤 Milton Russell Latta
- 👤 Timothy Carl Strand
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:25
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1362; G11B7/08; G11B7/085; G11B7/08547
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
65 words
In or for an optical data storage system in which data is stored along tracks on an optical storage medium, an optical storage head comprising an anamorphic holographic mirror so located in the head relative to its anamorphism as to focus an input light beam incident on the mirror in a direction instantly parallel to the track which the head is following onto the track.
Claim 2
Dependent Claim
65 words
In or for an optical data storage system in which data is stored along tracks on an optical storage medium, an optical storage head comprising an anamorphic holographic mirror so located in the head relative to its anamorphism as to focus an input light beam incident on the mirror in a direction instantly parallel to the track which the head is following onto the track.
Claim 3
Dependent Claim
67 words
A head as claimed in claim 2, the storage medium being an optical disc having concentric data tracks thereon, wherein the approach path of the incident optical beam in the region of the mirror is parallel to the plane of the disc and tangential to the track at the point of address of the head, the mirror diffracting the incident beam substantially perpendicularly onto the storage medium.
Claim 4
Dependent Claim
36 words
A head as claimed in claim 2, including a folding mirror to turn the incident beam in a plane parallel to the disc from a substantially radial to tangential disposition relative to the data track addressed.
Claim 5
Dependent Claim
32 words
A head as claimed in claim 2 or claim 3, wherein the anamorphism of the mirror accommodates an elliptical incident beam having its minor axis perpendicular to the plane of the disc.
Claim 6
Dependent Claim
23 words
An optical data storage system including a head as claimed in claim 4 and a gallium arsenide laser generating the incident optical beam.
References Cited (Backward Citations)
No citation records indexed.
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