US4592637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focus detecting device
Assignee: Canon Inc
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Filing: 1984-10-17
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Granted: 1986-06-03
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Expires: 2004-10-17
Abstract
Abstract This specification discloses a focus detecting device for detecting the focus state of an objective lens by sensing the light from a light source reflected by an object by means of a sensor provided near a plane conjugate with respect to the predetermined imaging plane of the objective lens, wherein the sensor is inclined with respect to the conjugate plane to thereby increase the energy of the light received by the sensor during non-in-focus.
Inventors
- 👤 Shigeyuki Suda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:26
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/30; G02B7/32
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
136 words
A focus detecting device for detecting a focus state of an objective lens, comprising: sensor means provided near a plane conjugate with respect to a predetermined imaging plane of the objective lens for sensing light from a light source reflected by an object; and detection light receiving optical system for introducing the light through the objective lens to said sensor means; said sensor means being inclined with respect to said conjugate plane, an optical axis of said detection light receiving optical system being offset from an optical axis of the objective lens, said sensor means having a first and a second light-receiving area with said optical axis of said detection light-receiving optical system as the boundary, and said first and second light-receiving areas putting out electrical signals corresponding to the incident light independently of each other.
Claim 2
Dependent Claim
136 words
A focus detecting device for detecting a focus state of an objective lens, comprising: sensor means provided near a plane conjugate with respect to a predetermined imaging plane of the objective lens for sensing light from a light source reflected by an object; and detection light receiving optical system for introducing the light through the objective lens to said sensor means; said sensor means being inclined with respect to said conjugate plane, an optical axis of said detection light receiving optical system being offset from an optical axis of the objective lens, said sensor means having a first and a second light-receiving area with said optical axis of said detection light-receiving optical system as the boundary, and said first and second light-receiving areas putting out electrical signals corresponding to the incident light independently of each other.
Claim 3
Dependent Claim
31 words
A focus detecting device according to claim 1, wherein said sensor is inclined in a direction in which the energy of received light during the non-in-focus of the objective lens increases.
Claim 4
Dependent Claim
19 words
A focus detecting device according to claim 2, wherein the center of said sensor lies on said conjugate plane.
Claim 5
Dependent Claim
32 words
A focus detecting device according to claim 1, wherein said sensor is disposed so that a light-receiving surface thereof lies at a position whereat the reflected light from the object is converged.
References Cited (Backward Citations)
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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) | 1989-06-02 | 1989-12-02 | 1990-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-02 | 1993-12-02 | 1994-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-02 | 1997-12-02 | 1998-06-03 | $7700.00 | Window Closed / Lapsed |