US3601027A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Viewing mirror and light shield arrangement for a single lens reflex camera
Assignee: Nikon Corp
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Filing: 1968-08-01
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Granted: 1971-08-24
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Expires: 1988-08-01
Abstract
Abstract An arrangement for the viewing mirror of a single lens reflex camera having a through-the-lens photometric system, is provided for effectively shielding the photocell from light rays entering the objective lens during viewing and exposure operations. A pivotable baffle plate is provided within the mirror compartment of the camera, which is pivoted between the two light shielding positions upon movement of the viewing mirror to its raised and lowered positions by the mirror mechanism of the camera. In addition to the viewing mirror, a concave mirror is disposed behind and pivoted to the viewing mirror to direct the image light rays back to the rear of the viewing mirror where they are then reflected onto the photocell surface. The pivotal connection between the concave mirror and the viewing mirror is such that a large aperture or window is provided for the viewing mirror so that a large bundle of image rays will pass through the semitransparent viewing mirror and be directed onto the surface of the photocell through a relay lens system. The concave mirror effectively seals the aperture or window in the viewing mirror when the mirrors are in their raised positions.
Inventors
- 👤 Shigeo Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:19
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
182 words
A single lens reflex camera having an exposure meter comprising, in combination, a partially transparent viewing mirror pivotable between an operative viewing position wherein said mirror lies between an objective lens and a film and reflects a part of the light passing through the objective Lens into a finder, and a nonoperative exposure position wherein said mirror is clear of the light path of said objective lens, means for pivoting said viewing mirror, a light-sensitive element positioned behind said partially transparent mirror to receive the light passing through said objective lens and said mirror, a pivotable light shield arranged to block any light rays passing around said viewing mirror, means for displacing said light shield means out of the light path from said objective lens to said film upon displacement of said viewing mirror from its operative position into its nonoperative position, and a lens system provided for the light-sensitive element interposed between the viewing mirror and the element, the displacement of said light shield means being to a position in which it covers the lens system provided for said light-sensitive element.
Claim 2
Dependent Claim
182 words
A single lens reflex camera having an exposure meter comprising, in combination, a partially transparent viewing mirror pivotable between an operative viewing position wherein said mirror lies between an objective lens and a film and reflects a part of the light passing through the objective Lens into a finder, and a nonoperative exposure position wherein said mirror is clear of the light path of said objective lens, means for pivoting said viewing mirror, a light-sensitive element positioned behind said partially transparent mirror to receive the light passing through said objective lens and said mirror, a pivotable light shield arranged to block any light rays passing around said viewing mirror, means for displacing said light shield means out of the light path from said objective lens to said film upon displacement of said viewing mirror from its operative position into its nonoperative position, and a lens system provided for the light-sensitive element interposed between the viewing mirror and the element, the displacement of said light shield means being to a position in which it covers the lens system provided for said light-sensitive element.
Claim 3
Dependent Claim
66 words
A single lens reflex camera according to claim 1, wherein said light-sensitive element is positioned at the bottom of a camera, a concave mirror for reflecting the light rays passing through said viewing mirror onto said element through said lens system, said concave mirror being pivotally mounted on said viewing mirror, and means interconnecting said two mirrors for moving said concave mirror with said viewing mirror.
Claim 4
Dependent Claim
129 words
A single lens reflex camera according to claim 1, wherein the means for displacing said light shield means includes an interlocking lever pivoted intermediate its ends on the camera body, one arm of said lever being in the path of movement of said viewing mirror, said light shield means being pivotable between the first position where it is out of the light path from said objective and the second position where it covers said lens system, and resilient means for biasing said light shield means to said first position where it abuts the other arm of the interlocking lever, movement of the viewing mirror toward its nonoperative position pivoting the interlocking lever to pivot said light shield means against the bias of said resilient means to its second position.
Claim 5
Dependent Claim
59 words
A single lens reflex camera according to claim 2, wherein said means interconnecting the viewing and concave mirrors includes a driving lever pivoted at its upper end to the camera body, a pin and slot connection between the driving lever and the viewing mirror, and a link interconnecting the lower ends of the driving lever and the concave mirror.
Claim 6
Dependent Claim
200 words
A single lens reflex camera having an exposure meter comprising, in combination, a partially transparent viewing mirror pivotable between an operative viewing position where said mirror lies between the objective lens and the film and reflects part of the light passing through said objective lens into the viewfinder, and a nonoperative exposure position wherein said mirror is clear of the light path of said objective lens, a light-sensitive element positioned at the bottom of a camera to receive the light passing through said objective lens and said mirror, a concave mirror mounted on said viewing mirror to be pivotable between an operative position wherein said concave mirror reflects the light passing through said viewing mirror onto said light-sensitive element and a nonoperative position wherein said concave mirror is clear of the light path of said objective lens and blocks the light from said viewfinder, means interconnecting said mirrors, including a lever pivotally mounted on the camera and connected by a pin and slot connection to said viewing mirror and by a link connecting said lever and said concave mirror so that the concave mirror is displaced to its nonoperative position upon displacement of said viewing mirror to its nonoperative position.
Claim 7
Dependent Claim
200 words
A single lens reflex camera having an exposure meter comprising, in combination, a partially transparent viewing mirror pivotable between an operative viewing position where said mirror lies between the objective lens and the film and reflects part of the light passing through said objective lens into the viewfinder, and a nonoperative exposure position wherein said mirror is clear of the light path of said objective lens, a light-sensitive element positioned at the bottom of a camera to receive the light passing through said objective lens and said mirror, a concave mirror mounted on said viewing mirror to be pivotable between an operative position wherein said concave mirror reflects the light passing through said viewing mirror onto said light-sensitive element and a nonoperative position wherein said concave mirror is clear of the light path of said objective lens and blocks the light from said viewfinder, means interconnecting said mirrors, including a lever pivotally mounted on the camera and connected by a pin and slot connection to said viewing mirror and by a link connecting said lever and said concave mirror so that the concave mirror is displaced to its nonoperative position upon displacement of said viewing mirror to its nonoperative position.
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) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |