Patent US4927241A successfully refreshed from Google Patents.
US4927241A
Expired / Lapsed
US
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Optical imaging system having an electronically variable focal length and optical image sensor provided with such a system
Assignee: US Philips Corp
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Filing: 1989-09-25
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Granted: 1990-05-22
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Expires: 2009-09-25
Abstract
Abstract An imaging system having an electronically variable focal length is obtained by arranging, one after the other, a lens system (10) different sectors of which have different focal lengths and a liquid crystal diaphragm (20). By selecting sectors of the lens system with the aid of the diaphragm, an object (30) can be sharply imaged also at different object lengths in an image plane (40).
Inventors
- 👤 Karel E. Kuijk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:26
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1343; G02F1/134309; G02B; G02B3/00; G02B3/10; G02B3/12; G02B3/14; G02F1/29; G02F1/294
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
An optical imaging system having an electronically variable focal length, comprising a system of lenses and a liquid crystal layer, characterized in that the system of lenses is divided into a plurality of sectors having different, constant focal lengths and in that the liquid crystal layer forms part of an electronically variable diaphragm including at least first and second terminals disposed on the surface of said layer for selecting sectors of the system of lenses and hence selecting a focal length.
Claim 2
Dependent Claim
81 words
An optical imaging system having an electronically variable focal length, comprising a system of lenses and a liquid crystal layer, characterized in that the system of lenses is divided into a plurality of sectors having different, constant focal lengths and in that the liquid crystal layer forms part of an electronically variable diaphragm including at least first and second terminals disposed on the surface of said layer for selecting sectors of the system of lenses and hence selecting a focal length.
Claim 3
Dependent Claim
24 words
An optical imaging system as claimed in claim 1, characterized in that sectors of the system of lenses having different focal lengths merge gradually.
Claim 4
Dependent Claim
21 words
An optical imaging system as claimed in claim 1, characterized in that transitions between sectors of the lens system are discontinuous.
Claim 5
Dependent Claim
81 words
An optical imaging system as claimed in claim 1, characterized in that the electronically variable diaphragm comprises electrodes disposed on opposed sides of the liquid crystal layer, which electrodes cover substantially the entire surface of the diaphragm and in which at least one of the electrodes has a plurality of terminals so that the electrode can be connected simultaneously to different voltages producing a voltage gradient in the electrode so that a gradually varying electric field is formed in the crystal.
Claim 6
Dependent Claim
19 words
An optical imaging system as claimed in claim 1, characterized in that the system of lenses is rotationally symmetrical.
Claim 7
Dependent Claim
25 words
An optical imaging system as claimed in claim 1, characterized in that the sectors of the system of lenses have a substantially equal surface area.
Claim 8
Dependent Claim
62 words
The optical imaging system as claimed in claim 1, further including a radiation sensitive surface and a control circuit, said control circuit having an input connected to said radiation sensitive surface and an output connected to said electronically variable focal length optical imaging system for varying the focal length of the system dependent upon the image focussed on said radiation sensitive surface.
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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) | 1993-05-21 | 1993-11-20 | 1994-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-21 | 1997-11-20 | 1998-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-21 | 2001-11-20 | 2002-05-22 | $7700.00 | Window Closed / Lapsed |