US3791276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light measuring apparatus for camera shutter control mechanisms
Assignee: Minolta Co Ltd
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Filing: 1971-06-04
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Granted: 1974-02-12
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Expires: 1991-06-04
Abstract
Abstract In a single lens reflex camera having a focal plane shutter with a light reflecting surface, the light receptive elements are mounted outside of the direct light path from the objective lens to the film so as to receive light reflected from both the film and the light reflecting surface of the focal plane shutter. Structure is mounted to block selected light rays reflected from the film and/or the light reflecting surface of the focal plane shutter.
Inventors
- 👤 H Ueda
- 👤 T Egawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:27
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12; G03B7/00; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09974
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
100 words
In a single lens reflex camera having a focal plane shutter with a light reflecting surface and an objective lens, the improvement comprising: at least two light receptive elements mounted outside of the direct light path from said objective lens to the light sensitive surface of the film for receiving light reflected from said light sensitive surface and/or said light reflecting surface of said focal plane shutter for generating respective signals in accordance with the reflected light incident thereon; and means for blocking selected light rays reflected from said light sensitive surface and/or the surface of said focal plane shutter.
Claim 2
Dependent Claim
100 words
In a single lens reflex camera having a focal plane shutter with a light reflecting surface and an objective lens, the improvement comprising: at least two light receptive elements mounted outside of the direct light path from said objective lens to the light sensitive surface of the film for receiving light reflected from said light sensitive surface and/or said light reflecting surface of said focal plane shutter for generating respective signals in accordance with the reflected light incident thereon; and means for blocking selected light rays reflected from said light sensitive surface and/or the surface of said focal plane shutter.
Claim 3
Dependent Claim
52 words
Apparatus as in claim 1 further comprising cylindrically shaped membErs for mounting each of said at least two light receptive elements and wherein said means for blocking is a slidable extension of the surface of said cylindrically shaped members and includes means for retaining said means for blocking in a given position.
Claim 4
Dependent Claim
55 words
Apparatus as in claim 1 further comprising means for mounting each of said at least two light receptive elements, and said means for blocking comprises a member integral with said means for mounting and extending therefrom for blocking a portion of said light rays reflected from said light sensitive surface and/or said light reflecting surface.
Claim 5
Dependent Claim
25 words
Apparatus as in claim 1 wherein said at least two light receptive elements are mounted symmetrically relative to the optical axis of said objective lens.
Claim 6
Dependent Claim
150 words
In a single lens reflex camera having a focal plane shutter with a light reflecting surface, an objective lens, the aperture of said objective lens has a diameter d, and the focal distance is h, the improvement comprising: means for mounting at least two light receptive elements symmetrically with respect to the optical axis of said objective lens outside of the direct light path from said objective lens to the light sensitve surface of a film and for receiving light reflected from said light sensitive surface and/or said light reflecting surface of said focal plane shutter; and wherein one of said at least two light receptive elements is mounted a distance LR from the optical axis of said objective lens and a disance LS normal to the surface of said focal plane shutter wherein LS and LR are selected so that LR and LS are respectively minimum and maximum distances.
Claim 7
Dependent Claim
150 words
In a single lens reflex camera having a focal plane shutter with a light reflecting surface, an objective lens, the aperture of said objective lens has a diameter d, and the focal distance is h, the improvement comprising: means for mounting at least two light receptive elements symmetrically with respect to the optical axis of said objective lens outside of the direct light path from said objective lens to the light sensitve surface of a film and for receiving light reflected from said light sensitive surface and/or said light reflecting surface of said focal plane shutter; and wherein one of said at least two light receptive elements is mounted a distance LR from the optical axis of said objective lens and a disance LS normal to the surface of said focal plane shutter wherein LS and LR are selected so that LR and LS are respectively minimum and maximum distances.
References Cited (Backward Citations)
US3124049A
Cited
US3353462A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |