US3909608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reproducing device for the optical reading out of a record carrying an embossed print
Assignee: Thales SA
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Filing: 1973-12-18
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Granted: 1975-09-30
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Expires: 1993-12-18
Abstract
Abstract The invention relates to optical systems for reproducing information-bearing signals recorded upon a record in the form of a track of diffractive elements. The optical detection with a luminous spot is performed by means of four photodetector elements arranged side by side; the two sets of symmetrical elements are respectively connected to two differential amplifiers.
Inventors
- 👤 Merer Jean Pierre Le
- 👤 Carvennec Francois Le
- 👤 Jean Pierre Lacotte
- 👤 Roland Malissin
- 👤 Claude Puech
- 👤 Claude Tinet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:08
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0908; G11B7/0917; G11C; G11C13/00; G11C13/04; G11C13/048
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
182 words
A reproducing device for the reading-out of a pulse time modulated waveform stored onto a record in the form of an embossed print having an axis, and carried by an engraved face of said record; said print being of uniform width, and constituted along said axis by a succession of diffractive elements having non-uniform length and spacing at least equal to said width; said reproducing device comprising: illumination means for projecting a concentrated spot of radiant energy onto said embossed print, photoelectric detection means arranged for selectively collecting the diffracted radiant energy emerging from the portion of said embossed print illuminated by said concentrated spot, and moving means arranged for following with said concentrated spot the path of said embossed print; said photoelectric detection means comprising four photodetector elements arranged side by side and supplied symmetrically with said diffracted radiant energy; the two first of said photodetectors elements being disposed symmetrically in relation to a first plane normal to said axis; the two second of said photodetector elements being disposed symmetrically in relation to a second plane normal to said first plane.
Claim 2
Dependent Claim
182 words
A reproducing device for the reading-out of a pulse time modulated waveform stored onto a record in the form of an embossed print having an axis, and carried by an engraved face of said record; said print being of uniform width, and constituted along said axis by a succession of diffractive elements having non-uniform length and spacing at least equal to said width; said reproducing device comprising: illumination means for projecting a concentrated spot of radiant energy onto said embossed print, photoelectric detection means arranged for selectively collecting the diffracted radiant energy emerging from the portion of said embossed print illuminated by said concentrated spot, and moving means arranged for following with said concentrated spot the path of said embossed print; said photoelectric detection means comprising four photodetector elements arranged side by side and supplied symmetrically with said diffracted radiant energy; the two first of said photodetectors elements being disposed symmetrically in relation to a first plane normal to said axis; the two second of said photodetector elements being disposed symmetrically in relation to a second plane normal to said first plane.
Claim 3
Dependent Claim
60 words
A reproducing device as claimed in claim 1, wherein said photoelectric detection means are associated with amplifier means; said amplifier means comprising at least one differential amplifier; said first two photodetector elements being respectively connected to the two inputs of said differential amplifier for supplying an electrical signal indicating the passage through said spot of one of said diffractive elements.
Claim 4
Dependent Claim
100 words
A reproducing device as claimed in claim 1, wherein sAid photoelectric detection means are associated with amplifier means; said amplifier means comprising at least one differential amplifier; said two second photodetector elements being respectively connected to the two inputs of said differential amplifier for supplying an error signal representative of the eccentricity of said spot in relation to said diffractive elements; said illumination means comprising an objective lens associated with an electromechanical transducer designed to displace said objective lens perpendicularly to said axis and at a constant distance from said record; said electromechanical transducer being controlled, by said error signal.
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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |