US3924063A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable optical wedge for scanning a light beam in an apparatus for reading an optically encoded disc
Assignee: US Philips Corp
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Filing: 1974-04-29
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Granted: 1975-12-02
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Expires: 1994-04-29
Abstract
Abstract An apparatus is described for optically reading a record carrier. Deflection of the read beam over the record carrier can be achieved with the aid of an assembly of a plano-concave and a plano-convex lens, the radiuses of curvature of the curved surfaces of the lenses being equal, and the distances between the curved surfaces being very small. The beam-deflection element is compact, may be disposed near the read objective, and need not meet stringent requirements as regards surface quality.
Inventors
- 👤 Carel Arthur Jan Simons
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:27
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/085; G11B7/08547
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
346 words
An apparatus for reading a record carrier on which information is stored in an optically readable structure of areas and intermediate regions which are arranged along tracks, of the type wherein the apparatus includes a radiation source which supplies a read beam, an objective system for focussing the read beam to a read spot on the optical structure of the record carrier, a beam deflecting element for moving the read spot with respect to the record carrier, and a radiation-sensitive detection system for converting the read beam which is modulated by the areas and intermediate regions into an electrical signal, the improvement wherein the beam-deflecting element comprises an assembly of a plano-concave lens and a plano-convex lens, the concave surface of the first lens facing the convex surface of the second lens, said plano-convex and plano-concave lens surfaces having substantially the same radius of curvature and are disposed at a distance which is substantially smaller than said radius of curvature, a first axis associated with said plano-convex lens and being defined as a line perpendicular to the optical axis of the objective system and passing therethrough, a second axis associated with said plano-convex lens and being defined as a line passing through the first axis and through the optical axis of the objective system and perpendicular to both the first axis and the optical axis of the objective system, a third axis associated with said plano-concave lens and being defined as a line parallel to the first axis and passing through the optical axis of the objective system, a fourth axis associated with said plano-concave lens and passing through the optical axis of the objective system parallel to said second axis, two of said first through fourth axes that are perpendicularly oriented being pivotal axes, the lens associated with the particular pivotal axis being pivotally mounted to angularly move about said associated axis, one of the pivotal axes being parallel to the section of track on which the objective system is focussed, said lens assembly being in the vicinity of a pupil of said objective lens.
Claim 2
Independent Claim
346 words
An apparatus for reading a record carrier on which information is stored in an optically readable structure of areas and intermediate regions which are arranged along tracks, of the type wherein the apparatus includes a radiation source which supplies a read beam, an objective system for focussing the read beam to a read spot on the optical structure of the record carrier, a beam deflecting element for moving the read spot with respect to the record carrier, and a radiation-sensitive detection system for converting the read beam which is modulated by the areas and intermediate regions into an electrical signal, the improvement wherein the beam-deflecting element comprises an assembly of a plano-concave lens and a plano-convex lens, the concave surface of the first lens facing the convex surface of the second lens, said plano-convex and plano-concave lens surfaces having substantially the same radius of curvature and are disposed at a distance which is substantially smaller than said radius of curvature, a first axis associated with said plano-convex lens and being defined as a line perpendicular to the optical axis of the objective system and passing therethrough, a second axis associated with said plano-convex lens and being defined as a line passing through the first axis and through the optical axis of the objective system and perpendicular to both the first axis and the optical axis of the objective system, a third axis associated with said plano-concave lens and being defined as a line parallel to the first axis and passing through the optical axis of the objective system, a fourth axis associated with said plano-concave lens and passing through the optical axis of the objective system parallel to said second axis, two of said first through fourth axes that are perpendicularly oriented being pivotal axes, the lens associated with the particular pivotal axis being pivotally mounted to angularly move about said associated axis, one of the pivotal axes being parallel to the section of track on which the objective system is focussed, said lens assembly being in the vicinity of a pupil of said objective lens.
Claim 3
Dependent Claim
32 words
An apparatus as claimed in claim 1, wherein the radiation path from the radiation source to the beam deflecting element includes a correction element in the form of a single positive lens.
Claim 4
Dependent Claim
127 words
An apparatus as claimed in claim 1, further comprising a pair of rods, the lenses being rigidly secured by said rods, which are rotatable about said pivotal axes in bearings, the line between the bearings associated with a lens passing through the center of curvature of the curved surface of the relevant lens, magnetic poles, filamentary windings on each lens facing said magnet poles, the filamentary winding of one of said lenses of said assembly comprising means for receiving a control signal for centering the read spot relative to a track to be read, and the filamentary windings of the other lens of said assembly comprising means for receiving a control signal for positioning the read spot in the longitudinal direction of a track to be read.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |