US4611243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic camera having improved support for optical low-pass filter
Assignee: Pentax Corp
•
Filing: 1984-04-30
•
Granted: 1986-09-09
•
Expires: 2004-04-30
Abstract
Abstract An electronic camera of a type employing an optical low-pass filter to eliminate moire pattern effects wherein the overall size of the camera is reduced and an optimum shutter efficiency is obtained. The camera includes, in order, an objective lens, a retractable mirror, a focal plane shutter, and an image pickup device. The optical low-pass filter is positioned between the retractable mirror and the focal plane shutter. The arrangement avoids interference with the path of the retractable mirror and prevents an increase in the distance between the focal length shutter and the image pickup device.
Inventors
- 👤 Tahei Morisawa
- 👤 Harumi Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:03
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/50; H04N23/55
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
181 words
In an electronic camera of a type having, in order, an objective lens, a retractable image reflecting mirror, a focal plane shutter, and an electronic image pickup device, and an optical low-pass filter disposed in an optical path between said objective lens and said image pickup device, the improvement comprising: means for positioning said optical low-pass filter between said mirror and said optical plane shutter; said positioning means comprising a supporting frame which comprises a detachable holding plate for securing said optical low-pass filter to said frame, a base portion extending parallel to an optical axis of said objective lens, a filter holding portion adapted to receive said low-pass filter extending upwardly from a rear end of said base portion and to which said holding plate is secured, and first and second side portions disposed on opposite sides of said base portion and said filter holding portion and extending perpendicular thereto, said side surface portions having at least a pair of surfaces for supporting said retractable mirror at an angle of substantially 45 degrees in a lowered position of said mirror.
Claim 2
Dependent Claim
181 words
In an electronic camera of a type having, in order, an objective lens, a retractable image reflecting mirror, a focal plane shutter, and an electronic image pickup device, and an optical low-pass filter disposed in an optical path between said objective lens and said image pickup device, the improvement comprising: means for positioning said optical low-pass filter between said mirror and said optical plane shutter; said positioning means comprising a supporting frame which comprises a detachable holding plate for securing said optical low-pass filter to said frame, a base portion extending parallel to an optical axis of said objective lens, a filter holding portion adapted to receive said low-pass filter extending upwardly from a rear end of said base portion and to which said holding plate is secured, and first and second side portions disposed on opposite sides of said base portion and said filter holding portion and extending perpendicular thereto, said side surface portions having at least a pair of surfaces for supporting said retractable mirror at an angle of substantially 45 degrees in a lowered position of said mirror.
Claim 3
Dependent Claim
22 words
The electronic camera of claim 1, wherein said holding plate is disposed on a side of said frame towards said objective lens.
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) | 1989-09-08 | 1990-03-10 | 1990-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-08 | 1994-03-10 | 1994-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-08 | 1998-03-10 | 1998-09-09 | $7700.00 | Window Closed / Lapsed |