Patent US4739360A successfully refreshed from Google Patents.
US4739360A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light metering device for camera
Assignee: Canon Inc
•
Filing: 1986-04-22
•
Granted: 1988-04-19
•
Expires: 2006-04-22
Abstract
Abstract A light metering device for single lens reflex camera having photoelectric transducer elements arranged in the optical path of a finder thereof. The photoelectric transducer elements are arranged ahead of a focusing screen as viewed from the direction of finder light, and an area corresponding to a clear portion of the focusing screen is made either to have a photoelectric transducer structure of narrower width than in the environmental area, or to be light-metered by another or separate light metering optical system.
Inventors
- 👤 Hiroshi Ohmura
- 👤 Tokuichi Tsunekawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:36
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09976
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
120 words
A light metering device for a camera having a finder optical system with a focusing screen plate having a clear portion formed therein and arranged in said system, comprising: a photoelectric transducer arranged in advance of said focusing screen plate of said finder optical system on an optical path, including: a first photoelectric transducer element of fine width arranged in a finder optical path corresponding to that area of said focusing screen plate which is other than said clear portion; and a second photoelectric transducer element of fine width arranged in the finder optical path corresponding to said clear portion of said focusing screen plate, said second photoelectric transducer element being narrower in width than said first photoelectric transducer element.
Claim 2
Dependent Claim
120 words
A light metering device for a camera having a finder optical system with a focusing screen plate having a clear portion formed therein and arranged in said system, comprising: a photoelectric transducer arranged in advance of said focusing screen plate of said finder optical system on an optical path, including: a first photoelectric transducer element of fine width arranged in a finder optical path corresponding to that area of said focusing screen plate which is other than said clear portion; and a second photoelectric transducer element of fine width arranged in the finder optical path corresponding to said clear portion of said focusing screen plate, said second photoelectric transducer element being narrower in width than said first photoelectric transducer element.
Claim 3
Dependent Claim
40 words
A camera according to claim 1, wherein the width of said first photoelectric transducer element is on the order of several tens of microns, and the width of said second photoelectric transducer element is on the order of several microns.
Claim 4
Dependent Claim
116 words
A light metering device for a camera with a member having a light diffusing area and a clear area arranged in an optical path of a finder optical system, comprising: photoelectric transducer means arranged in the optical path ahead of said member of said finder optical system, including: a first photoelectric transducer element of fine width arranged in the finder optical path corresponding to said light diffusing area other than said clear area of said member; and a second photoelectric transducer element of fine width arranged in the finder optical path corresponding to said clear area of said member, said second photoelectric transducer element being formed narrower in the width than said first photoelectric transducer element.
Claim 5
Dependent Claim
116 words
A light metering device for a camera with a member having a light diffusing area and a clear area arranged in an optical path of a finder optical system, comprising: photoelectric transducer means arranged in the optical path ahead of said member of said finder optical system, including: a first photoelectric transducer element of fine width arranged in the finder optical path corresponding to said light diffusing area other than said clear area of said member; and a second photoelectric transducer element of fine width arranged in the finder optical path corresponding to said clear area of said member, said second photoelectric transducer element being formed narrower in the width than said first photoelectric transducer element.
Claim 6
Dependent Claim
40 words
A camera according to claim 3, wherein the width of said first photoelectric transducer element is on the order of several tens of microns, and the width of said second photoelectric transducer element is on the order of several microns.
Claim 7
Dependent Claim
149 words
A light metering device for a camera with a focusing screen plate having a light diffusing area and a clear area arranged in an optical path of a finder optical system, comprising: (a) first photoelectric transducer elements arranged near but in advance of said screen plate on the optical path, said elements being formed with fine width arranged in an optical path corresponding to said diffusing area; (b) a light metering optical system for metering light of the finder optical path corresponding to said clear area of said plate, said light metering optical system comprising a different optical axis center from said finder optical system; and (c) second photoelectric transducer elements arranged in the optical path of said light metering optical system, said second photoelectric transducer elements being arranged on the same plane as the first photoelectric transducer elements, but outside the optical path of the finder optical system.
Claim 8
Dependent Claim
149 words
A light metering device for a camera with a focusing screen plate having a light diffusing area and a clear area arranged in an optical path of a finder optical system, comprising: (a) first photoelectric transducer elements arranged near but in advance of said screen plate on the optical path, said elements being formed with fine width arranged in an optical path corresponding to said diffusing area; (b) a light metering optical system for metering light of the finder optical path corresponding to said clear area of said plate, said light metering optical system comprising a different optical axis center from said finder optical system; and (c) second photoelectric transducer elements arranged in the optical path of said light metering optical system, said second photoelectric transducer elements being arranged on the same plane as the first photoelectric transducer elements, but outside the optical path of the finder optical system.
Claim 9
Dependent Claim
25 words
A camera according to claim 5, wherein the width of said first photoelectric transducer elements are made on the order of several tens of microns.
Claim 10
Dependent Claim
48 words
A camera according to claim 5, further comprising: said light metering optical system having a reflecting member for reflecting an optical path portion corresponding to said clear portion of said focusing screen plate to a direction different from to the optical axis center of said finder optical system.
Claim 11
Dependent Claim
25 words
A camera according to claim 6, wherein the width of said second photoelectric transducer elements are made on the order of several tens of microns.
Claim 12
Dependent Claim
21 words
A camera according to claim 5, wherein said first and said second photoelectric transducer elements are constructed with the same element.
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) | 1991-04-19 | 1991-10-19 | 1992-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-19 | 1995-10-19 | 1996-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-19 | 1999-10-19 | 2000-04-19 | $7700.00 | Window Closed / Lapsed |