US4564267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable-focal-length lens
Assignee: Canon Inc
•
Filing: 1982-12-27
•
Granted: 1986-01-14
•
Expires: 2002-12-27
Abstract
Abstract Disclosed is a variable-focal-length lens whose focal length can be electrically controlled by applying an electric field of uniform intensity distribution to a compound lens including at least one lens formed of electrooptic crystal and varying the intensity of the applied electric field.
Inventors
- 👤 Yoshifumi Nishimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:19
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02B; G02B15/00; G02F1/294
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A variable-focal-length lens comprising: a lens system including at least one set of electrooptic crystals cemented together on curved surfaces thereof so that the directions of their respective axes of rotatory inversion are coincident with each other and so that the directions of their respective two corresponding rotation axes differ from each other; means for applying an electric field of uniform intensity distribution to said cemented surfaces of said electrooptic crystals so as to make said cemented surfaces refraction surfaces having a lens action; and means for varying the intensity of the electric field to be applied, to thereby vary the focal length of said lens system.
Claim 2
Dependent Claim
107 words
A variable-focal-length lens comprising: a lens system including at least one set of electrooptic crystals cemented together on curved surfaces thereof so that the directions of their respective axes of rotatory inversion are coincident with each other and so that the directions of their respective two corresponding rotation axes differ from each other; means for applying an electric field of uniform intensity distribution to said cemented surfaces of said electrooptic crystals so as to make said cemented surfaces refraction surfaces having a lens action; and means for varying the intensity of the electric field to be applied, to thereby vary the focal length of said lens system.
Claim 3
Dependent Claim
26 words
A variable-focal-length lens according to claim 1, wherein a polarizing plate is disposed on the light path of a light beam passing through said compound lens.
Claim 4
Dependent Claim
24 words
A variable-focal-length lens according to claim 1, wherein said means for applying an electric field comprises parallel flat electrodes attached to said electrooptic crystals.
Claim 5
Dependent Claim
33 words
A variable-focal-length lens according to claim 1, further comprising means provided on the light path of a light beam passing through said compound lens for varying the polarization direction of said light beam.
Claim 6
Dependent Claim
34 words
A variable-focal-length lens according to claim 3, wherein the intensity of the electric field to be applied is varied by controlling the voltage of a variable power source connected to said parallel flat electrodes.
Claim 7
Dependent Claim
34 words
A variable-focal-length lens according to claim 4, wherein said means for varying the polarization direction of said light beam comprises a polarizing plate and means for rotating said polarizing plate about the optical axis.
References Cited (Backward Citations)
US3167607A
Cited
DE1191980B
Cited
US3520592A
Cited
US3758201A
Cited
SU505980A1
Cited
US4037929A
Cited
JPS5273748A
Cited
US4190330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-13 | 1989-07-15 | 1990-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-13 | 1993-07-15 | 1994-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-13 | 1997-07-15 | 1998-01-14 | $7700.00 | Window Closed / Lapsed |