Patent US3868703A successfully refreshed from Google Patents.
US3868703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light measuring device for shutter control mechanism
Assignee: Minolta Co Ltd
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Filing: 1973-05-14
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Granted: 1975-02-25
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Expires: 1993-05-14
Abstract
Abstract A camera having detecting means for detecting a light passed through the objective lens, comprising photocells which receive light rays transmitted through an objective lens and which are disposed in front of a light sensitive member but out of the way of the light path of the focusing image light passed through the objective lens, the first screen (the front screen) of a focal plain shutter which is started to run out when said photocells receive the reflected light from the first screen surface at the side confronting to the objective lens and from the light sensitive surface of the photosensitive element, and an exposure time control device which is activated at the same time when the first screen of the focal plain shutter is started to run out, so that the starting time when the second screen of the focal plain shutter is started to run is thereby controlled, wherein the scattering property of the first screen of the focal plain shutter equal to the scattering property of the light sensitive member. The surface of the front shutter contain facing the objective has a film of thin transparent material thereon, the material having dispersed therein particles having a refractive index different from that of said material.
Inventors
- 👤 Hiroshi Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:24
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: 8
Claim 1
Independent Claim
197 words
In a photographic camera of the type including an objective lens and a light sensitive member, light shielding means movably disposed in front of and adjacent said light sensitive member, said light shielding means including a front shutter curtain movable from a cocked position to a rest position thereof to initiate exposure of said light sensitive member, and further including a rear shutter curtain movable from a cocked position to a rest position thereof to terminate the exposure, an electric circuit means for timing the actuation of said rear curtain, the improvement comprising: said front shutter curtain including a surface facing said objective lens and having a light scattering layer thereon with substantially the same reflecting power and scattering property as that of said light sensitive member; photoelectric means connected in said circuit means and mounted within said camera for receiving light passing through said objective lens and reflected from said light scattering layer when said front shutter curtain is in front of light sensitive member, from said light scattering layer and said light sensitive surface when said light sensitive member is being uncovered, and from said light sensitive member when said light sensitive member is uncovered.
Claim 2
Dependent Claim
197 words
In a photographic camera of the type including an objective lens and a light sensitive member, light shielding means movably disposed in front of and adjacent said light sensitive member, said light shielding means including a front shutter curtain movable from a cocked position to a rest position thereof to initiate exposure of said light sensitive member, and further including a rear shutter curtain movable from a cocked position to a rest position thereof to terminate the exposure, an electric circuit means for timing the actuation of said rear curtain, the improvement comprising: said front shutter curtain including a surface facing said objective lens and having a light scattering layer thereon with substantially the same reflecting power and scattering property as that of said light sensitive member; photoelectric means connected in said circuit means and mounted within said camera for receiving light passing through said objective lens and reflected from said light scattering layer when said front shutter curtain is in front of light sensitive member, from said light scattering layer and said light sensitive surface when said light sensitive member is being uncovered, and from said light sensitive member when said light sensitive member is uncovered.
Claim 3
Dependent Claim
65 words
The camera according to claim 1 wherein said surface of said front shutter curtain facing said objective lenS has a film of thin transparent material coated thereon, said material having dispersed therein particles having a refractive index different from that of said material, thereby imparting to said front shutter curtain the scattering property which is substantially the same as that of said light sensitive member.
Claim 4
Dependent Claim
39 words
The camera according to claim 1 wherein said surface of said front shutter curtain facing said objective lens has a thin layer of a high polymer of epoxy resin coated thereon, said resin having dispersed therein zinc sulfide particles.
Claim 5
Dependent Claim
36 words
The camera according to claim 1 wherein said surface of said front shutter curtain facing said objective lens has a thin layer of epoxy resin coated thereon, said resin having dispersed therein titanium white (TiO2) particles.
Claim 6
Dependent Claim
35 words
The camera according to claim 1 wherein said surface of said front shutter facing said objective lens has a thin layer of epoxy resin coated thereon, said resin having dispersed therein chrome yellow (PbCrO4) particles.
Claim 7
Dependent Claim
33 words
The camera according to claim 1 wherein said surface of said front shutter facing said objective lens has a thin layer of epoxy resin coated thereon, said resin having dispersed therein graphite particles.
Claim 8
Dependent Claim
33 words
The camera according to claim 1 wherein said surface of said front shutter facing said objective lens has a thin layer of epoxy resin coated thereon, said resin having dispersed therein carbon particles.
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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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |