US4552445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focus condition detecting device for cameras
Assignee: Minolta Co Ltd
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Filing: 1984-08-14
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Granted: 1985-11-12
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Expires: 2004-08-14
Abstract
Abstract In a focus condition detecting device of the type in which a pair of re-imaging lenses together with a condenser lens form a pair of re-images of an object image on a line sensor such that the distance between the corresponding points of the re-images on the line-sensor varies with the focus condition of a camera objective lens forming the objective image, the line sensor is located in front of a plane conjugate with a predetermined focal plane of the camera objective lens with respect to the condenser lens and the re-imaging lenses, so that the distance between the corresponding points of the first and second re-images on the line-sensor can be detected with resolution higher than one pitch length of the photocells of the line sensor.
Inventors
- 👤 Hiromu Mukai
- 👤 Toshihiko Karasaki
- 👤 Kunio Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:11
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34; G02B7/346
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
A focus condition detecting device for a camera having an objective lens which forms an object image, said device comprising: a pair of re-imaging optical systems arranged symmetrically with one another with respect to the optical axis of said objective lens for re-imaging said object image as first and second re-images; and a line sensor arranged optically in front of a plane conjugate with a predetermined focal plane of said objective lens with respect to said re-imaging optical systems and extending in the direction perpendicular to the optical axis of said objective lens so that said first and second re-images are formed thereon, the distance between the corresponding points of said first and second re-images on said line sensor varying with the focus condition of said objective lens.
Claim 2
Dependent Claim
128 words
A focus condition detecting device for a camera having an objective lens which forms an object image, said device comprising: a pair of re-imaging optical systems arranged symmetrically with one another with respect to the optical axis of said objective lens for re-imaging said object image as first and second re-images; and a line sensor arranged optically in front of a plane conjugate with a predetermined focal plane of said objective lens with respect to said re-imaging optical systems and extending in the direction perpendicular to the optical axis of said objective lens so that said first and second re-images are formed thereon, the distance between the corresponding points of said first and second re-images on said line sensor varying with the focus condition of said objective lens.
Claim 3
Dependent Claim
85 words
A focus condition detecting device as defined in claim 1, wherein one of said re-imaging optical systems includes a condenser lens having a center aligned with the optical axis of said objective lens and a first re-imaging lens having a center located laterally of the optical axis of said objective lens and the other of said re-imaging optical system includes said condenser lens and a second re-imaging lens arranged symmetrically with said first re-imaging lens with respect to the optical axis of said objective lens.
Claim 4
Dependent Claim
22 words
A focus condition device as defined in claim 2, wherein said device is formed into a unit module attachable to said camera.
References Cited (Backward Citations)
US3875401A
Cited
US3875401B1
Cited
JPS5295221A
Cited
JPS55157220A
Cited
US4384210A
Cited
US4436395A
Cited
JPS5888709A
Cited
JPS58106511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-11 | 1989-05-13 | 1989-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-11 | 1993-05-13 | 1993-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-11 | 1997-05-13 | 1997-11-12 | $7700.00 | Window Closed / Lapsed |