Patent US3658409A successfully refreshed from Google Patents.
US3658409A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital light deflector
Assignee: Hitachi Ltd
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Filing: 1970-07-01
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Granted: 1972-04-25
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Expires: 1990-07-01
Abstract
Abstract Electro-optic crystal elements and uniaxial birefringent crystals are alternately aligned together and an additional electro-optic crystal element followed by a polarizing plate is further aligned with the last stage birefringent crystal. Each of the electro-optic crystal elements has opposite faces provided thereon with transparent electrodes to which a half-wavelength voltage is selectively applied whereby undesired light components are shut off by the polarizing plate to thereby improve S/N (signal to noise) ratio.
Inventors
- 👤 Chiaki Shimbo
- 👤 Hiroomi Kojima
- 👤 Michio Sekiya
- 👤 Kiyoo Takeyasu
- 👤 Sadao Nomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:10
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
258 words
A digital light deflector comprising: a plurality of light deflection units each of which comprises an electro-optic crystal element having opposite faces cut perpendicularly to the c-axis thereof and provided with a pair of transparent electrodes on said opposite faces thereof, and a uniaxial birefringent crystal having opposite faces cut at its cutting angle specified with respect to the optic axis thereof and aligned with the electro-optic crystal element, said light deflectors being aligned in cascade to form an alternate alignment therewith, and the thicknesses of the respective birefringent crystals being different from each other; input means for supplying an input light beam to one of the outermost electro-optic crystal elements of the first stage deflection unit of said alternate alignment; an electro-optic crystal element disposed behind the last stage deflection unit, the two principal axes of said electro-optical crystal being at an angle of 45* with the vibration plane of linearly polarized input light; a polarizing plate disposed behind the last named electro-optic crystal element, the orientation of the polarization plane of said polarizing plate being at an angle of one of 0* and 90* with said vibration plane of said linearly polarized input light; and control means for selectively supplying a half-wavelength voltage for the electro-optic crystal elements to the respective pair of electRodes of the electro-optic crystal elements, whereby the plane of polarization of the light beam applied is rotated in the respective electro-optic crystal elements in response to the application of the voltage and an output light beam is obtained from the polarizing plate.
Claim 2
Dependent Claim
258 words
A digital light deflector comprising: a plurality of light deflection units each of which comprises an electro-optic crystal element having opposite faces cut perpendicularly to the c-axis thereof and provided with a pair of transparent electrodes on said opposite faces thereof, and a uniaxial birefringent crystal having opposite faces cut at its cutting angle specified with respect to the optic axis thereof and aligned with the electro-optic crystal element, said light deflectors being aligned in cascade to form an alternate alignment therewith, and the thicknesses of the respective birefringent crystals being different from each other; input means for supplying an input light beam to one of the outermost electro-optic crystal elements of the first stage deflection unit of said alternate alignment; an electro-optic crystal element disposed behind the last stage deflection unit, the two principal axes of said electro-optical crystal being at an angle of 45* with the vibration plane of linearly polarized input light; a polarizing plate disposed behind the last named electro-optic crystal element, the orientation of the polarization plane of said polarizing plate being at an angle of one of 0* and 90* with said vibration plane of said linearly polarized input light; and control means for selectively supplying a half-wavelength voltage for the electro-optic crystal elements to the respective pair of electRodes of the electro-optic crystal elements, whereby the plane of polarization of the light beam applied is rotated in the respective electro-optic crystal elements in response to the application of the voltage and an output light beam is obtained from the polarizing plate.
References Cited (Backward Citations)
US3499700A
Cited
US3391972A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |