Patent US2197747A successfully refreshed from Google Patents.
Patent US4507772A successfully refreshed from Google Patents.
US4507772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Playback optical system for video discs
Assignee: Olympus Corp
•
Filing: 1983-05-04
•
Granted: 1985-03-26
•
Expires: 2003-05-04
Abstract
Abstract A playback optical system for video discs comprising a light shield plate arranged in the vicinity of the pupil of the read-out lens, said optical system facilitating design of said read-out lens and permitting adjustment of focal length.
Inventors
- 👤 Kimiaki Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:23
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/24; G02B3/00; G11; G11B; G11B7/00; G11B7/08; G11B7/085; G11B7/12; G11B7/135; G11B7/1365; G11B7/1392; G11B7/13922
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
107 words
A playback optical system for video discs comprising a light source, a lens system for condensing a light beam emitted from said light source on the disc surface, a light shield member arranged on the optical axis of said lens system in the vicinity of the pupil of said lens system between said light source and disc surface and having a light shield part at the center thereof to shield the center part of the light beam to advance from said light source to said disc surface through said lens system and a detector for receiving the light reflected on said disc surface through said lens system.
Claim 2
Dependent Claim
107 words
A playback optical system for video discs comprising a light source, a lens system for condensing a light beam emitted from said light source on the disc surface, a light shield member arranged on the optical axis of said lens system in the vicinity of the pupil of said lens system between said light source and disc surface and having a light shield part at the center thereof to shield the center part of the light beam to advance from said light source to said disc surface through said lens system and a detector for receiving the light reflected on said disc surface through said lens system.
Claim 3
Dependent Claim
32 words
A playback optical system for video discs according to claim 1 wherein the ratio of semi-diameter of said light shield part to semi-diameter of said light shield plate is at least 0.3.
Claim 4
Dependent Claim
30 words
A playback optical system for video discs according to claim 1 wherein the ratio of semi-diameter of said light shield part to semi-diameter of said light shield plate is 0.5.
References Cited (Backward Citations)
US3497704A
Cited
US3809478A
Cited
US4160269A
Cited
US3956582A
Cited
US3891968A
Cited
US3969575A
Cited
US4062623A
Cited
US4037965A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-25 | 1988-09-24 | 1989-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-25 | 1992-09-24 | 1993-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-25 | 1996-09-24 | 1997-03-26 | $7700.00 | Window Closed / Lapsed |