US5825016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focus detection device and accompanying optical equipment
Assignee: Minolta Co Ltd
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Filing: 1996-03-06
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Granted: 1998-10-20
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Expires: 2016-03-06
Abstract
Abstract Where a person is being photographed, for example, both light from the person located at closer range and light from the background located farther away enter the photodetector elements. Where the contrast of the background is high, the rate at which the information from the background contributes to the focus detection becomes larger, which hinders accurate focus detection with regard to the person. In this case, the focus detection device divides a predetermined focus area into smaller areas and detects focus condition in each smaller area.
Inventors
- 👤 Junko Nagahata
- 👤 Hiroshi Ueda
- 👤 Akio Kinba
- 👤 Tsuyoshi Kishimoto
- 👤 Tatsuo Nakashima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:47
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34; G02B7/346
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
123 words
A focus detection device, including an optical system which forms first and second images, and a sensor having photodetector elements which detect said first and second images, for detecting a focus condition of an objective lens based on a relative position between said first and second images, said device comprising: a first focus detector which divides said first image into plural areas and detects a first relative distance between said first and second images; a second focus detector which divides one of said areas into smaller areas and uses said smaller areas to detect a second relative distance between said first and second images; and a calculator which calculates a final relative distance based on one of said first and second relative distances.
Claim 2
Dependent Claim
123 words
A focus detection device, including an optical system which forms first and second images, and a sensor having photodetector elements which detect said first and second images, for detecting a focus condition of an objective lens based on a relative position between said first and second images, said device comprising: a first focus detector which divides said first image into plural areas and detects a first relative distance between said first and second images; a second focus detector which divides one of said areas into smaller areas and uses said smaller areas to detect a second relative distance between said first and second images; and a calculator which calculates a final relative distance based on one of said first and second relative distances.
Claim 3
Dependent Claim
66 words
A focus detection device as claimed in claim 1, further comprising: a determiner which determines whether or not closer and farther objects exist in said one of said areas provided by said first focus detector; and a controller which controls operations of said first and second focus detectors; wherein said controller controls an operation of said second focus detector based on a determination by said determiner.
Claim 4
Dependent Claim
39 words
A focus detection device as claimed in claim 2, wherein said controller operates said second focus detector when it is determined that closer and farther objects exist in said one of said areas provided by said first focus detector.
Claim 5
Dependent Claim
38 words
A focus detection device as claimed in claim 2, wherein said determiner operates based on a contrast of said one of said areas provided by said first focus detector and a correlation between said first and second images.
Claim 6
Dependent Claim
18 words
A focus detection device as claimed in claim 2, wherein said determiner operates based on an object magnification.
Claim 7
Dependent Claim
30 words
A focus detection device as claimed in claim 5, wherein said controller operates said second focus detector when said determiner determines said object magnification is larger than a predetermined value.
Claim 8
Dependent Claim
36 words
A focus detection device as claimed in claim 1, wherein said second focus detector detects said second relative distance that is in a predetermined range of said first relative distance detected by said first focus detector.
Claim 9
Dependent Claim
28 words
A focus detection device as claimed in claim 1, wherein said controller prevents said second focus detector from operating when focus detection is executed for the first time.
Claim 10
Dependent Claim
145 words
A focus detection device, including an optical system which forms a first image and a second image, and a sensor having photodetector elements which detect said first and second images, for detecting a focus condition of an objective lens based on a relative position between said first and second images, said device comprising: a selector which divides said first image into plural areas and selects an area having a highest contrast in said plural areas; a first focus detector which uses a thus selected area to detect a first relative distance between said first and second images; a second focus detector which divides said selected area into smaller areas and uses said smaller areas to detect a second relative distance between said first and second images; and a calculator which calculates a final relative distance based on one of said first and second relative distances.
Claim 11
Dependent Claim
145 words
A focus detection device, including an optical system which forms a first image and a second image, and a sensor having photodetector elements which detect said first and second images, for detecting a focus condition of an objective lens based on a relative position between said first and second images, said device comprising: a selector which divides said first image into plural areas and selects an area having a highest contrast in said plural areas; a first focus detector which uses a thus selected area to detect a first relative distance between said first and second images; a second focus detector which divides said selected area into smaller areas and uses said smaller areas to detect a second relative distance between said first and second images; and a calculator which calculates a final relative distance based on one of said first and second relative distances.
Claim 12
Dependent Claim
58 words
A focus detection device as claimed in claim 9, further comprising: a determiner which determines whether or not closer and farther objects exist in said selected area; and a controller which controls operations of said first and second focus detectors; wherein said controller controls an operation of said second focus detector based on a determination of said determiner.
Claim 13
Dependent Claim
30 words
A focus detection device as claimed in claim 10, wherein said controller operates said second focus detector when it is determined closer and farther objects exist in said selected area.
Claim 14
Dependent Claim
30 words
A focus detection device as claimed in claim 10, wherein said determiner operates based on a contrast of said selected area and a correlation between said first and second images.
Claim 15
Dependent Claim
18 words
A focus detection device as claimed in claim 10, wherein said determiner operates based on an object magnification.
Claim 16
Dependent Claim
31 words
A focus detection device as claimed in claim 13, wherein said controller operates said second focus detector when said determiner determines that said object magnification is larger than a predetermined value.
Claim 17
Dependent Claim
99 words
A focus detection device, comprising: a first focus detector which detects focus condition of a taking lens to a predetermined area in an object field; a determiner which determines whether or not closer and farther objects exist in said predetermined area; a divider which divides said predetermined area into smaller areas when said determiner determines closer and farther objects exist in said predetermined area; a second focus detector which detects focus condition in said smaller areas; a magnification calculator which calculates an object magnification; a controller which controls an operation of said focus detector based on said object magnification.
Claim 18
Dependent Claim
99 words
A focus detection device, comprising: a first focus detector which detects focus condition of a taking lens to a predetermined area in an object field; a determiner which determines whether or not closer and farther objects exist in said predetermined area; a divider which divides said predetermined area into smaller areas when said determiner determines closer and farther objects exist in said predetermined area; a second focus detector which detects focus condition in said smaller areas; a magnification calculator which calculates an object magnification; a controller which controls an operation of said focus detector based on said object magnification.
Claim 19
Dependent Claim
27 words
A focus detection device as claimed in claim 15, wherein said controller operates said second focus detector when said object magnification is larger than a predetermined value.
Claim 20
Dependent Claim
29 words
A focus detection device as claimed in claim 15, wherein said determined operates based on a contrast of said predetermined area and correlation between said first and second images.
Claim 21
Dependent Claim
131 words
An optical apparatus having a focus detection device, said apparatus comprising: an objective lens; an optical system which is located behind said objective lens and forms first and second images; a sensor having photodetector elements which detect said first and second images; a first focus detector which divides said first image into plural areas and detects a first relative distance between said first and second images; a second focus detector which divides one of said areas into smaller areas and utilizes said smaller areas to detect a second relative distance between said first and second images; a calculator which calculates a final relative distance based on one of said first and second relative distances; and a controller which controls said objective lens in focus position based on said final relative distance.
Claim 22
Dependent Claim
131 words
An optical apparatus having a focus detection device, said apparatus comprising: an objective lens; an optical system which is located behind said objective lens and forms first and second images; a sensor having photodetector elements which detect said first and second images; a first focus detector which divides said first image into plural areas and detects a first relative distance between said first and second images; a second focus detector which divides one of said areas into smaller areas and utilizes said smaller areas to detect a second relative distance between said first and second images; a calculator which calculates a final relative distance based on one of said first and second relative distances; and a controller which controls said objective lens in focus position based on said final relative distance.
Claim 23
Dependent Claim
54 words
A focus detection device as claimed in claim 18, further comprising: a determiner which determines whether or not closer and farther objects exist in said one of said areas provided by said first focus detector, and wherein said controller controls an operation of said second focus detector based on a determination by said determiner.
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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) | 2001-10-19 | 2002-04-20 | 2002-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-19 | 2006-04-20 | 2006-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-19 | 2010-04-20 | 2010-10-20 | $7700.00 | Window Closed / Lapsed |