Patent US4289392A successfully refreshed from Google Patents.
US4289392A
Expired / Lapsed
US
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Pentagonal roof reflecting mirror assembly
Assignee: Minolta Co Ltd
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Filing: 1980-01-25
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Granted: 1981-09-15
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Expires: 2000-01-25
Abstract
Abstract A hollow pentagonal roof type reflecting mirror assembly for use in a viewfinder optical system of a single lens reflex camera is dust tight to prevent entry of dust into the inside hollow space and includes a filtered vent aperture to allow passage of vapor so that condensation will not occur inside the assembly. The assembly includes a hollow pentagonal body having roof and front mirrors and at least one vent aperture and a shielding or sealing member arranged to close the vent hole. The shielding or sealing member is made of a dust proof and ventilative material such as a foamed plastic, a paper and a cloth to filter out any dust particles.
Inventors
- 👤 Toshio Kobori
- 👤 Yasuo Yamazaki
- 👤 Isamu Uchida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:27
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
153 words
An improved pentagonal lightweight roof type reflecting mirror assembly, for mounting on a camera, free of dust and debris on its reflecting surfaces and not subject to condensation by trapped water vapor, comprising: a hollow, substantially airtight, plastic body member having a plurality of internal reflecting surfaces, at least one side of the body member capable of transmitting an image for internal reflection while an adjacent second side is capable of transmitting the image from the interior of the body member to a viewer, a third side of the body member is approximately diagonally juxtaposed across from the common edge of the first and second side and includes an aperture positioned outside the optical axis and extending therethrough, and a sealing member including a ventilative foamed plastic member fixed in and extending across the aperture, the sealing member being opaque to the transmission of light onto the reflective surfaces, while transmitting water vapor.
Claim 2
Dependent Claim
153 words
An improved pentagonal lightweight roof type reflecting mirror assembly, for mounting on a camera, free of dust and debris on its reflecting surfaces and not subject to condensation by trapped water vapor, comprising: a hollow, substantially airtight, plastic body member having a plurality of internal reflecting surfaces, at least one side of the body member capable of transmitting an image for internal reflection while an adjacent second side is capable of transmitting the image from the interior of the body member to a viewer, a third side of the body member is approximately diagonally juxtaposed across from the common edge of the first and second side and includes an aperture positioned outside the optical axis and extending therethrough, and a sealing member including a ventilative foamed plastic member fixed in and extending across the aperture, the sealing member being opaque to the transmission of light onto the reflective surfaces, while transmitting water vapor.
Claim 3
Dependent Claim
27 words
The invention of claim 1 wherein the foamed plastic member is a polyurethane resin foam having air pores sufficiently small to pass water vapor while trapping dust.
Claim 4
Dependent Claim
13 words
The invention of claim 2 wherein the sealing member includes a cloth member.
Claim 5
Dependent Claim
13 words
The invention of claim 2 wherein the sealing member includes a paper member.
Claim 6
Dependent Claim
229 words
An improved lightweight roof type reflecting mirror assembly for mounting on a camera, for use in a viewfinder optical system that is free of dust and debris on its internal reflecting mirror surfaces and further not subject to any condensation by trapped water vapor, comprising: a hollow, substantially airtight, plastic body member including a lower front wall having an inside surface on which a front reflective mirror is formed, a light exit wall for emitting the viewfinder light fluxes, a pair of side walls and a roof having inside roof faces on which a pair of roof reflective mirrors are formed respectively and an upper front roof support connected to and extending above the lower front wall, the upper front roof support including a first aperture, the light exit wall including a second aperture and at least one of the lower front wall and the light exit wall including a third aperture; a sealing member, including a ventilative foamed plastic member having air pores sufficiently small to pass water vapor while trapping dust and a thin opaque porous member, fixedly extends across the first aperture; an ocular lens assembly is operatively positioned in the second aperture, and a transparent internally reflecting member is operatively positioned in the third aperture to convey at least information relative to one of an object scene and camera settings through the viewfinder optical system.
Claim 7
Dependent Claim
229 words
An improved lightweight roof type reflecting mirror assembly for mounting on a camera, for use in a viewfinder optical system that is free of dust and debris on its internal reflecting mirror surfaces and further not subject to any condensation by trapped water vapor, comprising: a hollow, substantially airtight, plastic body member including a lower front wall having an inside surface on which a front reflective mirror is formed, a light exit wall for emitting the viewfinder light fluxes, a pair of side walls and a roof having inside roof faces on which a pair of roof reflective mirrors are formed respectively and an upper front roof support connected to and extending above the lower front wall, the upper front roof support including a first aperture, the light exit wall including a second aperture and at least one of the lower front wall and the light exit wall including a third aperture; a sealing member, including a ventilative foamed plastic member having air pores sufficiently small to pass water vapor while trapping dust and a thin opaque porous member, fixedly extends across the first aperture; an ocular lens assembly is operatively positioned in the second aperture, and a transparent internally reflecting member is operatively positioned in the third aperture to convey at least information relative to one of an object scene and camera settings through the viewfinder optical system.
Claim 8
Dependent Claim
14 words
The invention of claim 5 wherein the foamed plastic member is a polyurethane resin.
Claim 9
Dependent Claim
12 words
The invention of claim 6 wherein the opaque porous member is cloth.
Claim 10
Dependent Claim
12 words
The invention of claim 6 wherein the opaque porous member is paper.
Claim 11
Dependent Claim
18 words
The invention of claim 6 wherein a plurality of internally reflecting facets are provided on the reflecting member.
Claim 12
Dependent Claim
15 words
The invention of claim 9 wherein the reflecting member has a light incident concave surface.
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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) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |