US4063261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
View finder optical system
Assignee: Fujifilm Holdings Corp
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Filing: 1976-11-15
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Granted: 1977-12-13
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Expires: 1996-11-15
Abstract
Abstract A view finder optical system suitable for use in a single or twin lens reflex camera, using an image erecting-and-reflecting optical element. This optical element functions to change the image to be photographed appearing on the focusing plate of the camera to an erect real image which stands at a proper distance from the eyepiece of the camera. This makes it possible to increase the magnification of the view finder as much as required simply by using a short focal length eyepiece.
Inventors
- 👤 Makoto Kuboshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:41
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
99 words
A view finder optical system for a reflex camera having a focusing plate on the top thereof comprising a reflecting surface lying above the focusing plate for reflecting backward and downward the light from the focusing plate, a semi-transparent plane for reflecting the light from the reflecting surface forward in parallel to the face of the focusing plate, an image erecting-and-reflecting optical means positioned ahead of the semi-transparent plane to reflect the light therefrom backward thereto for forming an erect image behind the semi-transparent plane, and an eyepiece positioned behind the semi-transparent plane for viewing the erecting image therethrough.
Claim 2
Dependent Claim
99 words
A view finder optical system for a reflex camera having a focusing plate on the top thereof comprising a reflecting surface lying above the focusing plate for reflecting backward and downward the light from the focusing plate, a semi-transparent plane for reflecting the light from the reflecting surface forward in parallel to the face of the focusing plate, an image erecting-and-reflecting optical means positioned ahead of the semi-transparent plane to reflect the light therefrom backward thereto for forming an erect image behind the semi-transparent plane, and an eyepiece positioned behind the semi-transparent plane for viewing the erecting image therethrough.
Claim 3
Dependent Claim
76 words
A view finder optical system as defined in claim 1 wherein said reflecting surface consists of a plated face of a pentagonal dach prism, said semi-transparent surface consists of another face of the pentagonal dach prism, and said image erecting-and-reflecting optical means comprises a spherical-plane prism element the spherical surface of which is plated and the plane surface of which is fixed to a plane surface of the pentagonal prism opposite to said another face thereof.
Claim 4
Dependent Claim
50 words
A view finder optical system as defined in claim 2 further comprising two triangular prism elements cemented to each other, the whole area of the joint surface of the cemented triangular prism elements being semi-transparent, and the cemented prism elements being fixed to said semi-transparent surface of the pentagonal prism.
Claim 5
Dependent Claim
50 words
A view finder optical system as defined in claim 1 wherein said reflecting surface is a plated face of a pentagonal dach prism, said semi-transparent surface is another face of the pentagonal prism, and said image erecting-and-reflecting optical means comprises a combination of a Fresnel lens and a plane mirror.
Claim 6
Dependent Claim
60 words
A view finder optical system as defined in claim 1 wherein said reflecting surface is a plated face of a pentagonal dach prism, said semi-transparent surface is another face of the pentagonal prism, and said image erecting-and-reflecting optical means comprises a combination of planoconcave lens and a convex lens cemented together the plane surface of the cemented lens being plated.
Claim 7
Dependent Claim
51 words
A view finder optical system as defined in claim 1 wherein said reflecting surface is a plated face of a pentagonal dach prism, said semi-transparent surface is another face of the pentagonal prism, and said image erecting-and-reflecting optical means comprises a combination of a plane mirror and a cemented planoconvex lens.
Claim 8
Dependent Claim
28 words
A view finder optical system as defined in claim 1 wherein said reflecting surface, said semi-transparent plane and said image erecting-and-reflecting optical means are all plane reflecting mirrors.
References Cited (Backward Citations)
DE58001C
Cited
US2323005A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |