US3687026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A light reflective shutter control apparatus
Assignee: Minolta Co Ltd
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Filing: 1970-11-13
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Granted: 1972-08-29
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Expires: 1990-11-13
Abstract
Abstract A light scattering surface is mounted facing the objective lens to direct light to a photoelectric detector during movement of a shutter curtain so that shutter control is provided during the exposure. An integrating circuit formed by a condenser and the photoelectric detector actuate a switching circuit to control movement of a second shutter curtain to terminate the exposure.
Inventors
- 👤 Tatsuo Kobayashi
- 👤 Hiroshi Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:34
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B19/00; G03B19/02; G03B19/12; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09972
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
140 words
A shutter control apparatus for a photographic camera, comprising: an objective lens; means having a light sensitive surface; a first shutter curtain for initiating exposure of said light sensitive surface and having a light scattering surface facing said objective lens, said light scattering surface having a reflecting power of between 23 and 31 percent; a second shutter curtain for terminating said exposure; an electric timing means for controlling said second shutter curtain and including, a photoelectric member for receiving light passing through said objective lens and reflected from said light scattering surface and/or said light sensitive surface, a condenser connected to said photoelectric member to form an integrating circuit, a switching circuit responsive to said integrating circuit; and an electromagnet driven by said switching circuit to actuate said second shutter curtain after a delay period determined by said integrating circuit.
Claim 2
Dependent Claim
140 words
A shutter control apparatus for a photographic camera, comprising: an objective lens; means having a light sensitive surface; a first shutter curtain for initiating exposure of said light sensitive surface and having a light scattering surface facing said objective lens, said light scattering surface having a reflecting power of between 23 and 31 percent; a second shutter curtain for terminating said exposure; an electric timing means for controlling said second shutter curtain and including, a photoelectric member for receiving light passing through said objective lens and reflected from said light scattering surface and/or said light sensitive surface, a condenser connected to said photoelectric member to form an integrating circuit, a switching circuit responsive to said integrating circuit; and an electromagnet driven by said switching circuit to actuate said second shutter curtain after a delay period determined by said integrating circuit.
Claim 3
Dependent Claim
15 words
A shutter control apparatus as in claim 1, wherein said reflecting power is 26.7 percent.
Claim 4
Dependent Claim
26 words
A shutter control apparatus as in claim 1, wherein said first shutter curtain is mounted closer to said light sensitive surface than said second shutter curtain.
Claim 5
Dependent Claim
87 words
A shutter control apparatus as in claim 1, further comprising: a view finder; a mirror movable between a viewing position for directing the light passing through the objective lens to said view finder and a retracted position for allowing the light to impinge on said light sensitive surface; a retaining member for retaining said first shutter curtain in a cocked position; means for releasing said first shutter curtain with said mirror in said retracted position; and delay means for delaying the operation of said means for releasing.
Claim 6
Dependent Claim
61 words
A shutter control apparatus as in claim 4, further comprising: a power switch for said electric timing means having a normally open position and a closed position with said mirror in said retracted position; and said means for releasing includes an electromagnet connected to said switching circuit and actuated by the closing of said power switch to release said retaining member.
Claim 7
Dependent Claim
26 words
A shutter control apparatus as in claim 4, wherein the photosensitive element is mounted between said mirror and said objective lens facing said light sensitive material.
Claim 8
Dependent Claim
20 words
A shutter control apparatus as in claim 6, further comprising a plurality of photoelectric elements facing said light sensitive surface.
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |