US3969575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Opto-electronic focus detection system
Assignee: US Philips Corp
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Filing: 1974-12-06
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Granted: 1976-07-13
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Expires: 1994-12-06
Abstract
Abstract In an opto-electronic focus detection system for determining a deviation between the plane of focussing of an objective and a radiation-reflecting surface the path of a focussing beam which is reflected by said surface includes an assembly of two radiation-sensitive detection elements. The difference in the output signals of said elements is proportional to said deviation. By disposing a lenslike element of which only the outer zone has a lens action before the detection elements, the measuring range can be extended while maintaining the sensitivity for small deviations.
Inventors
- 👤 Gerrit Berend Gerritsen
- 👤 Gerard Eduard VAN Rosmalen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:38
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/40; G02B3/00; G02B3/02; G02B3/08; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0908; G11B7/0917; G11B2007/0924
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
An opto-electronic focus-detection system for use in an apparatus for writing information in an information surface of a record carrier body as an optically readable radiation-reflecting structure with a writing beam, comprising an objective system for focussing said writing beam on said carrier body, a radiation source which emits a narrow focus detecting beam passing eccentrically through said objective of the write apparatus, two radiation-sensitive detection elements for intercepting the focus detecting beam which is reflected by the record carrier body and which passes the objective for a second time after said reflection, and a lens like element in the path of the reflected focus detecting beam to the radiation-sensitive detection elements, only the outer zone of said lens like element having a lens action, and the central part of said lens like element passing said focus detecting beam without affecting the direction of the focus detecting beam.
Claim 2
Dependent Claim
148 words
An opto-electronic focus-detection system for use in an apparatus for writing information in an information surface of a record carrier body as an optically readable radiation-reflecting structure with a writing beam, comprising an objective system for focussing said writing beam on said carrier body, a radiation source which emits a narrow focus detecting beam passing eccentrically through said objective of the write apparatus, two radiation-sensitive detection elements for intercepting the focus detecting beam which is reflected by the record carrier body and which passes the objective for a second time after said reflection, and a lens like element in the path of the reflected focus detecting beam to the radiation-sensitive detection elements, only the outer zone of said lens like element having a lens action, and the central part of said lens like element passing said focus detecting beam without affecting the direction of the focus detecting beam.
Claim 3
Dependent Claim
27 words
An opto-electronic system as claimed in claim 1, wherein the lenslike element comprises a single convex lens, the central parts of the convex lens faces being planar.
Claim 4
Dependent Claim
16 words
An opto-electronic system as claimed in claim 1, wherein the lenslike element comprises an annular lens.
Claim 5
Dependent Claim
148 words
An opto-electronic focus-detection system for use in an apparatus for reading information contained in an information surface of a record carrier as an optically readable radiation-reflecting structure with a reading beam, comprising an objective system for focussing said reading beam on said record carrier, a radiation source which emits a narrow focus detecting beam passing eccentrically through said objective of said record carrier reading apparatus, two radiation-sensitive detection elements for intercepting the focus detecting beam which is reflected by the record carrier and which passes the objective for a second time after said reflection, and a lens like element in the path of the reflected focussing beam to the radiation-sensitive detection elements, only the outer zone of said lens like element having a lens action, and the central part of said lens like element passing the focus detecting beam without affecting the direction of the focus detection beam.
Claim 6
Dependent Claim
148 words
An opto-electronic focus-detection system for use in an apparatus for reading information contained in an information surface of a record carrier as an optically readable radiation-reflecting structure with a reading beam, comprising an objective system for focussing said reading beam on said record carrier, a radiation source which emits a narrow focus detecting beam passing eccentrically through said objective of said record carrier reading apparatus, two radiation-sensitive detection elements for intercepting the focus detecting beam which is reflected by the record carrier and which passes the objective for a second time after said reflection, and a lens like element in the path of the reflected focussing beam to the radiation-sensitive detection elements, only the outer zone of said lens like element having a lens action, and the central part of said lens like element passing the focus detecting beam without affecting the direction of the focus detection beam.
Claim 7
Dependent Claim
28 words
An opto-electronic system as claimed in claim 4, wherein the lens like element comprises a single convex lens, the central parts of the convex lens faces being planar.
Claim 8
Dependent Claim
17 words
An opto-electronic system as claimed in claim 4, wherein the lens like element comprises an annular lens.
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) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |