US3838906A
Expired / Lapsed
US
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Optical switch
Assignee: Hitachi Ltd
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Filing: 1972-09-15
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Granted: 1974-10-01
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Expires: 1992-09-15
Abstract
Abstract An optical switch comprising an electro-optical crystal having optically positive or negative birefringency, a birefringent crystal having optically negative or positive birefringency and an electric power source connected with the electro-optical crystal for turning on and off the crystal, the electro-optical crystal and the birefringent crystal being arranged in cascade in such a manner that the sign of the birefringency of the former may be opposite to that of the latter, whereby the optical switch can effectively block an incident light having an incident angle as large as 30*, as is hardly possible with a conventional optical control device.
Inventors
- 👤 A Kumada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:53
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/0305; G02F1/0322; G02F1/05
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
AN OPTICAL SWITCH FOR USE IN A SPACIAL MODULATOR, COMPRISING A (4/4)-PLATE OF C-CUT GD2(MOO4)3 CRYSTAL IN THE SHAPE OF A COMB HAVING A PLURALITY OF DIGITATIONS EXTENDING PARALLEL IN THE DIRECTION OF (110) AND SEPARATED EQUIDISTANTLY FROM ONE ANOTHER; TRANSPARENT ELECTRODES DISPOSED ON ONE OF THE C-PLANES OF SAID COMB-LIKE ($/4)-PLATE EXCEPT ON THE COMMON PORTION WHERE SAID DIGITATIONS JOIN TOGETHER; TRANSPARENT ELECTRODES DISPOSED ON THE OTHER C-PLANE OF SAID COMB-LIKE ($/4)-PLATE, EXTENDING PARALLEL TO THE DIRECTION OF (110) AND SEPARATED EQUIDISTANTLY FROM ONE ANOTHER; A POWER SOURCE CONNECTED WITH EACH OF BOTH SAID TRANSPARENT ELECTRODES; AND A ($/4) PLATE OF BIAXIAL, OPTICALLY NEGATIVE CRYSTAL ARRANGED IN CASCADE WITH SAID ($/4)-PLATE OF GD2(MO04)3 CRYSTAL.
Claim 2
Dependent Claim
115 words
AN OPTICAL SWITCH FOR USE IN A SPACIAL MODULATOR, COMPRISING A (4/4)-PLATE OF C-CUT GD2(MOO4)3 CRYSTAL IN THE SHAPE OF A COMB HAVING A PLURALITY OF DIGITATIONS EXTENDING PARALLEL IN THE DIRECTION OF (110) AND SEPARATED EQUIDISTANTLY FROM ONE ANOTHER; TRANSPARENT ELECTRODES DISPOSED ON ONE OF THE C-PLANES OF SAID COMB-LIKE ($/4)-PLATE EXCEPT ON THE COMMON PORTION WHERE SAID DIGITATIONS JOIN TOGETHER; TRANSPARENT ELECTRODES DISPOSED ON THE OTHER C-PLANE OF SAID COMB-LIKE ($/4)-PLATE, EXTENDING PARALLEL TO THE DIRECTION OF (110) AND SEPARATED EQUIDISTANTLY FROM ONE ANOTHER; A POWER SOURCE CONNECTED WITH EACH OF BOTH SAID TRANSPARENT ELECTRODES; AND A ($/4) PLATE OF BIAXIAL, OPTICALLY NEGATIVE CRYSTAL ARRANGED IN CASCADE WITH SAID ($/4)-PLATE OF GD2(MO04)3 CRYSTAL.
Claim 3
Dependent Claim
128 words
An optical switch for use in a spacial modulator, comprising a ( lambda /2)-plate of c-cut Gd2(Mo04)3 crystal in the shape of a comb having a plurality of digitations extending parallel in the direction of (110) and separated equidistantly from one another; transparent electrodes disposed entirely on one of the c-planes of said comb-like ( lambda /2) plate except on the common portion where said digitations join together; transparent electrodes disposed on the other c-plane of said comb-like ( lambda /2)-plate, extending parallel to the direction of (110) and separated equidistantly from one another; a power source connected with each of both said transparent electrodes; and a ( lambda /2) plate of biaxial, optically negative crystal arranged in cascade with said ( lambda /2) plate of Gd2(MoO4)3 crystal.
Claim 4
Dependent Claim
128 words
An optical switch for use in a spacial modulator, comprising a ( lambda /2)-plate of c-cut Gd2(Mo04)3 crystal in the shape of a comb having a plurality of digitations extending parallel in the direction of (110) and separated equidistantly from one another; transparent electrodes disposed entirely on one of the c-planes of said comb-like ( lambda /2) plate except on the common portion where said digitations join together; transparent electrodes disposed on the other c-plane of said comb-like ( lambda /2)-plate, extending parallel to the direction of (110) and separated equidistantly from one another; a power source connected with each of both said transparent electrodes; and a ( lambda /2) plate of biaxial, optically negative crystal arranged in cascade with said ( lambda /2) plate of Gd2(MoO4)3 crystal.
Claim 5
Dependent Claim
124 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the caxis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a birefringent crystal plate disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said birefringent crystal plate are made of biaxial crystals having polarities opposite to each other and having such a mutual relationship that the products of the refractive index and the angle between the optical axes are equal for the respective crystal plates and wherein the products of the thickness and the diFference of refractive indices of birefringence are equal for the respective crystal plates.
Claim 6
Dependent Claim
124 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the caxis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a birefringent crystal plate disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said birefringent crystal plate are made of biaxial crystals having polarities opposite to each other and having such a mutual relationship that the products of the refractive index and the angle between the optical axes are equal for the respective crystal plates and wherein the products of the thickness and the diFference of refractive indices of birefringence are equal for the respective crystal plates.
Claim 7
Dependent Claim
21 words
A light control device comprising a pair of polarizers and an optical switch according to claim 3, disposed between said polarizers.
Claim 8
Dependent Claim
127 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the c axis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a c-plate of Gd2(MoO4)3 kept at a constant temperature above 160*C disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said c-plate are made of uni-axial crystals having polarities opposite to each other and have a mutual relationship expressed by the following formula with respect to the respective thicknesses d1 and d2 of the crystal plates, the refractive indices n1 and n2 and the differences Delta n1 and Delta n2 of refractive indices of birefringence: Delta n1d1/n12 Delta n2d2/n22
Claim 9
Dependent Claim
127 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the c axis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a c-plate of Gd2(MoO4)3 kept at a constant temperature above 160*C disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said c-plate are made of uni-axial crystals having polarities opposite to each other and have a mutual relationship expressed by the following formula with respect to the respective thicknesses d1 and d2 of the crystal plates, the refractive indices n1 and n2 and the differences Delta n1 and Delta n2 of refractive indices of birefringence: Delta n1d1/n12 Delta n2d2/n22
Claim 10
Dependent Claim
21 words
A light control device comprising a pair of polarizers and an optical switch according to claim 5, disposed between said polarizers.
Claim 11
Dependent Claim
127 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the c axis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a c-plate of Gd2(MoO4)3 kept at a constant temperature above 160*C disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said c-plate are made of uni-axial crystals having polarities opposite to each other and have the same thickness and a mutual relationship expressed by the following formula with respect to the respective refractive indices n1 and n2 of the crystal plates and the differences Delta n1 and Delta n2 of refractive indices of birefringence: Delta n1/n12 Delta n2/n22 .
Claim 12
Dependent Claim
127 words
An optical switch comprising: an electro-optical crystal plate having two opposite principal planes perpendicular to the c axis of said crystal; transparent electrodes each disposed on each of said principal planes; means for applying a voltage to said crystal through said transparent electrodes; and a c-plate of Gd2(MoO4)3 kept at a constant temperature above 160*C disposed in cascade with said electro-optical plate; wherein said electro-optical crystal plate and said c-plate are made of uni-axial crystals having polarities opposite to each other and have the same thickness and a mutual relationship expressed by the following formula with respect to the respective refractive indices n1 and n2 of the crystal plates and the differences Delta n1 and Delta n2 of refractive indices of birefringence: Delta n1/n12 Delta n2/n22 .
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |