US4034403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for positional control of a reading head in a device for reproducing optically coded video disk recordings
Assignee: US Philips Corp
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Filing: 1974-08-29
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Granted: 1977-07-05
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Expires: 1994-08-29
Abstract
Abstract An apparatus is described for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged video and/or audio signals coded in optical form, which apparatus comprises a source of radiation and a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this detector. By providing at least one grating, consisting of radiation-transmitting and radiation-absorbing stripes and on which an image of part of the grating-shaped structure of the information track in the vicinity of the portion of this track to be read may be formed, and a radiation-sensitive detection system, an accurate indication of axial and radial displacements of the optical imaging system relative to the information carrier can be obtained.
Inventors
- 👤 Klaas Compaan
- 👤 Gijsbertus Bouwhuis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:18
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
Apparatus for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged information signals coded in optical form, which apparatus comprises a source of radiation, a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this radiation-sensitive signal detector cell, a periodic grating which consists of radiation-transmitting and radiation-absorbing stripes, optical means in the path of the radiation emanating from the carrier for imaging on the grating part of the grating-shaped structure of the carrier information track in the vicinity of the portion of this track to be read as a plurality of stripes substantially parallel to the grating stripes, and a further radiation-sensitive detection system in the path of the radiation emanating from the grating, wherein the detection system produces a focus control signal for said optical means.
Claim 2
Dependent Claim
143 words
Apparatus for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged information signals coded in optical form, which apparatus comprises a source of radiation, a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this radiation-sensitive signal detector cell, a periodic grating which consists of radiation-transmitting and radiation-absorbing stripes, optical means in the path of the radiation emanating from the carrier for imaging on the grating part of the grating-shaped structure of the carrier information track in the vicinity of the portion of this track to be read as a plurality of stripes substantially parallel to the grating stripes, and a further radiation-sensitive detection system in the path of the radiation emanating from the grating, wherein the detection system produces a focus control signal for said optical means.
Claim 3
Dependent Claim
25 words
Apparatus as claimed in claim 1, characterized in that the grating and the further radiation-sensitive detection system are combined to form a grating-shaped radiation-sensitive detector.
Claim 4
Dependent Claim
26 words
Apparatus as claimed in claim 1, wherein said grating consisting of radiation-transmitting and radiation-absorbing stripes is arranged in the plane of the radiation-sensitive signal detector cell.
Claim 5
Dependent Claim
25 words
Apparatus as claimed in claim 3, characterized in that the grating comprises two component gratings, the grating stripes of which are mutually shifted in phase.
Claim 6
Dependent Claim
51 words
Apparatus as claimed in claim 3, further comprising a birefringent element in the radiation path in front of the grating, a polarization separating element in the radiation path behind the grating, said further radiation-sensitive detection system being inserted in the path of each of the sub-beams produced by the polarization-separating element.
Claim 7
Dependent Claim
43 words
Apparatus as claimed in claim 4, further comprising a beam splitter in the path of the beam of radiation which emerges from the information carrier, and a component grating inserted in the path of each of the sub-beams produced by the beam splitter.
Claim 8
Dependent Claim
41 words
Apparatus as claimed in claim 4, wherein the radiation-transmitting stripes of one of the component gratings projected on an imaginary plane perpendicular to the impinging radiation are aligned with the radiation-absorbing stripes of a similar projection of the other component grating.
Claim 9
Dependent Claim
32 words
Apparatus as claimed in claim 4, characterized in that the component gratings are color-selective, the radiation-transmitting stripes of one of the gratings being interlaced with the radiation-transmitting stripes of the other grating.
Claim 10
Dependent Claim
44 words
Apparatus as claimed in claim 4, wherein a grating and the radiation-sensitive detection system are combined to form a grating shaped radiation-sensitive detector, characterized in that the radiation-sensitive stripes of a component grating are interlaced with the radiation-sensitive stripes of the other component grating.
Claim 11
Dependent Claim
141 words
Apparatus for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged information signals coded in optical form, which apparatus comprises a source of radiation, a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this radiation-sensitive signal detector cell, a periodic grating which consists of radiation-transmitting and radiation-absorbing stripes, optical means in the path of the radiation emanating from the carrier for imaging on the grating a part of the grating-shaped structure of the carrier information track in the vicinity of the portion of this track to be read as a plurality of stripes substantially parallel to the grating stripes, and a further radiation-sensitive detection system in the path of the radiation emanating from the grating, wherein the detection system produces a radial tracking error signal.
Claim 12
Dependent Claim
141 words
Apparatus for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged information signals coded in optical form, which apparatus comprises a source of radiation, a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this radiation-sensitive signal detector cell, a periodic grating which consists of radiation-transmitting and radiation-absorbing stripes, optical means in the path of the radiation emanating from the carrier for imaging on the grating a part of the grating-shaped structure of the carrier information track in the vicinity of the portion of this track to be read as a plurality of stripes substantially parallel to the grating stripes, and a further radiation-sensitive detection system in the path of the radiation emanating from the grating, wherein the detection system produces a radial tracking error signal.
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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) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |