Patent US4294529A successfully refreshed from Google Patents.
US4294529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera
Assignee: Canon Inc
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Filing: 1979-08-28
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Granted: 1981-10-13
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Expires: 1999-08-28
Abstract
Abstract In the camera disclosed, a volume type diffraction device having an indicium recorded therein to be reproduced later, is sealed between transparent optical members and arranged in the finder optical path so that when illuminated by a light source at an oblique angle, the indicium is reproduced, represents photographic information to be displayed in the finder.
Inventors
- 👤 Yasuhisa Sato
- 👤 Sadahiko Tsuji
- 👤 Kazuo Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:44
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
91 words
A camera apparatus, comprising: a photo-taking optical system; a finder optical system including a focusing screen; a diffraction device arranged near one of a plurality of predetermined planes including a focal plane of said photo-taking optical system and an optically conjugate plane thereto and having recorded therein on indicium to be displayed; a pair of optical members, said diffraction device being supported and sealed between the two optical members; a light source for illuminating said diffraction device from an oblique direction; and an electrical power circuit for energizing said light source.
Claim 2
Dependent Claim
91 words
A camera apparatus, comprising: a photo-taking optical system; a finder optical system including a focusing screen; a diffraction device arranged near one of a plurality of predetermined planes including a focal plane of said photo-taking optical system and an optically conjugate plane thereto and having recorded therein on indicium to be displayed; a pair of optical members, said diffraction device being supported and sealed between the two optical members; a light source for illuminating said diffraction device from an oblique direction; and an electrical power circuit for energizing said light source.
Claim 3
Dependent Claim
21 words
An apparatus as in claim 1, wherein said diffraction device is constructed in the form of a volume type diffraction device.
Claim 4
Dependent Claim
23 words
An apparatus as in claim 1, wherein at least one of two optical members for supporting said diffraction device forms a focusing screen.
Claim 5
Dependent Claim
20 words
An apparatus as in claim 3, wherein said focusing screen simultaneously holds the light source for illuminating said diffraction device.
Claim 6
Dependent Claim
31 words
An apparatus as in claim 1, wherein at least one of said two optical members for supporting said diffraction device is a condenser lens for collecting light from said focusing screen.
Claim 7
Dependent Claim
22 words
An apparatus as in claim 2, wherein said diffraction device supported by said optical members is hermetically sealed in a dust-proof tube.
Claim 8
Dependent Claim
52 words
An apparatus as in claim 2, wherein one of said optical members simultaneously holds said light source for illuminating said diffraction device, and the light from the light source, said light source being oriented to be reflected a number of times within said optical member and then to illuminate said diffraction device.
Claim 9
Independent Claim
20 words
An apparatus as in claims 1, 3, 5, 6, 7, or 4, wherein said diffraction device includes a diffraction grating.
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) | 1984-10-12 | 1985-04-13 | 1985-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-12 | 1989-04-13 | 1989-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-12 | 1993-04-13 | 1993-10-13 | $7700.00 | Window Closed / Lapsed |