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US4696558A
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Focus condition detecting arrangement
Assignee: Minolta Co Ltd
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Filing: 1986-10-08
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Granted: 1987-09-29
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Expires: 2006-10-08
Abstract
Abstract In a focus condition detecting arrangement for use in a photographic camera, a focus condition detecting device including photo-sensor arrays having sensitivity with respect to a visible light and an infrared light from a target object to be photographed produces a focus condition detection signal based on an output of the photo-sensor arrays. A contrast detecting device which detects the visible light and the infrared light from the target object for detecting contrasts of the target object with respect to the respective lights, and a correcting means corrects the focus condition detection signal based on the output of the contrast detecting device, so that a corrected focus condition detection signal of the target object with respect to the visible light region is obtained.
Inventors
- 👤 Toshihiko Karasaki
- 👤 Toru Matsui
- 👤 Hiroshi Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:10
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34; G02B7/346
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
114 words
A focus condition detecting arrangement for use in a photographic camera, which comprises a focus condition detecting device including photo-sensor means having sensitivity with respect to a visible light and an infrared light from a target object to be photographed and adapted to produce a focus condition detection signal based on the output of the photo-sensor means, a contrast detecting means for detecting contrast of said target object with respect to the respective lights, and a correcting means for correcting the focus condition detection signal based on an output of said contrast detecting means, so that a corrected focus condition detection signal representing the focus condition with respect to the visible light is obtained.
Claim 2
Dependent Claim
114 words
A focus condition detecting arrangement for use in a photographic camera, which comprises a focus condition detecting device including photo-sensor means having sensitivity with respect to a visible light and an infrared light from a target object to be photographed and adapted to produce a focus condition detection signal based on the output of the photo-sensor means, a contrast detecting means for detecting contrast of said target object with respect to the respective lights, and a correcting means for correcting the focus condition detection signal based on an output of said contrast detecting means, so that a corrected focus condition detection signal representing the focus condition with respect to the visible light is obtained.
Claim 3
Dependent Claim
50 words
A focus condition detecting arrangement as claimed in claim 1, wherein said correcting means is adapted to effect the correction of the focus condition detection signal in accordance with a signal representing chromatic aberration of an objective lens of said photographic camera and the output of said contrast detecting means.
Claim 4
Dependent Claim
29 words
A focus condition detecting arrangement as claimed in claim 1, wherein the amount of correction of correcting said focus condition detection signal is divided into a plurality of values.
Claim 5
Dependent Claim
45 words
A focus condition detecting arrangement as claimed in claim 1, wherein the output of said contrast detecting means represents is a ratio of the contrast of the target object with respect to the visible light to the contrast thereof with respect to the infrared light.
Claim 6
Dependent Claim
76 words
A focus condition detecting arrangement as claimed in claim 1, wherein the correcting amount ΔX C for the focus condition detection signal is set as follows: ΔX.sub.C =0 when C V /C R ≧3, ΔX.sub.C =ΔX.sub.R (3-C.sub.V /C.sub.R)/4 when 1/3<C V /C R <3, and ΔX.sub.C =ΔX.sub.R when C V /C R ≦1/3 wherein C V and C R represent contrasts of the target object with respect to the visible light and the infrared light, respectively.
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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) | 1990-09-28 | 1991-03-30 | 1991-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-28 | 1995-03-30 | 1995-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-28 | 1999-03-30 | 1999-09-29 | $7700.00 | Window Closed / Lapsed |