US3876842A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for reading a flat record carrier
Assignee: US Philips Corp
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Filing: 1973-03-28
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Granted: 1975-04-08
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Expires: 1993-03-28
Abstract
Abstract An apparatus for reading a flat record carrier on which information is recorded in at least one track which has an optical structure is described. By projecting onto the plane of the track part to be read three spots of radiation the dimensions of which correspond to the smallest detail in the optical structure and the positions of which, viewed in the direction of width of the track, are different, and by inserting a radiationsensitive detector in each of the radiation beams emanating from the spots of radiation it is possible to ascertain whether a read beam is correctly directed on to the track to be read.
Inventors
- 👤 Gijsbertus Bouwhuis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:29
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0901; G11B7/0903
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
163 words
Apparatus for reading a flat record carrier on which information, for example video and/or audio information, is recorded in at least one track which has an optical structure, which apparatus is of the type wherein a source of radiation and a radiation-sensitive detection system convert radiation emitted by the radiation source and modulated by the record carrier into electric signals, the improvement, wherein the source of radiation comprises means for emitting at least three beams of radiation and for producing at least three spots of radiation in the plane of the track part to be read, the dimensions of these spots corresponding to the smallest detail in the optical structure while their positions, viewed in the direction of width of the track, are different, two of the spots viewed in the direction of the width of the track being on opposite sides of a third of said spots, and in that for each beam of radiation at least one radiation-sensitive detector is provided.
Claim 2
Dependent Claim
163 words
Apparatus for reading a flat record carrier on which information, for example video and/or audio information, is recorded in at least one track which has an optical structure, which apparatus is of the type wherein a source of radiation and a radiation-sensitive detection system convert radiation emitted by the radiation source and modulated by the record carrier into electric signals, the improvement, wherein the source of radiation comprises means for emitting at least three beams of radiation and for producing at least three spots of radiation in the plane of the track part to be read, the dimensions of these spots corresponding to the smallest detail in the optical structure while their positions, viewed in the direction of width of the track, are different, two of the spots viewed in the direction of the width of the track being on opposite sides of a third of said spots, and in that for each beam of radiation at least one radiation-sensitive detector is provided.
Claim 3
Dependent Claim
54 words
Apparatus as claimed in claim 1, for reading a reflecting record carrier, characterized in that the principal ray of at least one of the radiation beams which, viewed in the direction of width of the track, occupy the outer positions, intersects the plane of the track part to be read at an acute angle.
Claim 4
Dependent Claim
70 words
Apparatus as claimed in claim 1, characterized in that the radiation source is constituted by a point source of radiation and a grating which is disposed at a location behind the radiation and serves to project diffraction images of the point source of radiation onto the plane of the track to be read, the grating lines projected onto this plane being at acute angles to the direction of the track.
References Cited (Backward Citations)
US3198880A
Cited
US3155452A
Cited
US3452163A
Cited
US3530258A
Cited
US3673412A
Cited
US3743395A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |