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US4563093A
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Voltage and electric field measuring device using light
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1982-12-22
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Granted: 1986-01-07
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Expires: 2002-12-22
Abstract
Abstract A voltage and electric field measuring device is disclosed. The device uses light, including a polarizer, an electro-optic crystal consisting of a material having an optical rotatory power, and an analyzer arranged in the stated order in the direction of advancement of applied light, with a quarter-wave plate being disposed between the polarizer and crystal or between the crystal and analyzer. The angle of orientation ψ of the analyzer, relative to the optical axis of the crystal, is set to the product of θ and l, where θ represents the optical rotatory power, with respect to the applied light, of the crystal near a point at the center of a range of varying temperatures at the installation environment, and l represents the thickness of the crystal measured in the direction of advancement of light. The specified relation between ψ and θ·l maximizes the temperature stability of the device.
Inventors
- 👤 Kohji Tada
- 👤 Yoshiki Kuhara
- 👤 Masami Tatsumi
- 👤 Akihiko Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:28
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/08; G01R29/0864; G01R29/0878; G01R29/0885; G01R15/00; G01R15/14; G01R15/24; G01R15/241; G01R15/242; G01R29/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
198 words
A combination of parts for use in a device using light traveling along a given path and passing through an electro-optic crystal to measure either a voltage applied to the electro-optic crystal or an electric field in which the electro-optic crystal is immersed and which device is used in an environment wherein the temperature varies within a given temperature range, said combination comprising: a polarizer, an electro-optic crystal, and an analyzer each located in said given path and arranged in the stated order in the direction of advancement of light along said path, and a quarter-wave plate located in said path between said polarizer and said analyzer, said electro-optic crystal consisting of a material having an optical rotatory power, and said analyzer having its orientation rotated through an angle substantially equivalent to an angle ψ given by the following equation: ψ≈θl relative to the optical axis of said electro-optic crystal, where θ represents the optical rotatory power, with respect to the applied light, of said electro-optic crystal near a point at the center of said given temperature range, and l represents the thickness of the electro-optic crystal measured in the direction of advancement of light along said path.
Claim 2
Dependent Claim
198 words
A combination of parts for use in a device using light traveling along a given path and passing through an electro-optic crystal to measure either a voltage applied to the electro-optic crystal or an electric field in which the electro-optic crystal is immersed and which device is used in an environment wherein the temperature varies within a given temperature range, said combination comprising: a polarizer, an electro-optic crystal, and an analyzer each located in said given path and arranged in the stated order in the direction of advancement of light along said path, and a quarter-wave plate located in said path between said polarizer and said analyzer, said electro-optic crystal consisting of a material having an optical rotatory power, and said analyzer having its orientation rotated through an angle substantially equivalent to an angle ψ given by the following equation: ψ≈θl relative to the optical axis of said electro-optic crystal, where θ represents the optical rotatory power, with respect to the applied light, of said electro-optic crystal near a point at the center of said given temperature range, and l represents the thickness of the electro-optic crystal measured in the direction of advancement of light along said path.
Claim 3
Dependent Claim
36 words
The combination of claim 1 wherein said electro-optic crystal consists of a material selected from the group consisting of bismuth silicon oxide (Bi 12 SiO 20 ) and bismuth germanium oxide (Bi 12 GeO 20 ).
Claim 4
Dependent Claim
30 words
The combination of claim 1 wherein the wavelength of the applied light is between 800 and 900 nm, and the orientation ψ of said analyzer satisfies the following relation: (0.90θl-4.5)°≦ψ≦(1.03θl+2)°.
Claim 5
Dependent Claim
31 words
The combination of claim 1 wherein the wavelength of the applied light is between 800 and 900 nm, and the orientation ψ of said analyzer substantially satisfies the following relation: ψ=(0.95θl-1.5)°.
Claim 6
Dependent Claim
190 words
A combination of parts for use in a device using light traveling along a given path and passing through an electro-optic crystal to measure either a voltage applied to the electro-optic crystal or an electric field in which the electro-optic crystal is immersed and which device is used in an environment wherein the temperature varies within a given temperature range, said combination comprising: a polarizer, an electro-optic crystal, and an analyzer, each located in said given path and arranged in the stated order in the direction of advancement of light along said path, and a quarter-wave plate located in said path between said polarizer and said analyzer, said electro-optic crystal consisting of a material having an optical rotatory power, said analyzer having its orientation rotated through an angle of approximately 45° relative to the optical axis of said electro-optic crystal, and the thickness of said electro-optic crystal in the direction of the advancement of light being given by the following equation: l≈45°/θ where θ represents the optical rotatory power, with respect to the applied light, of said electro-optic crystal near a point at the center of said given temperature range.
Claim 7
Dependent Claim
190 words
A combination of parts for use in a device using light traveling along a given path and passing through an electro-optic crystal to measure either a voltage applied to the electro-optic crystal or an electric field in which the electro-optic crystal is immersed and which device is used in an environment wherein the temperature varies within a given temperature range, said combination comprising: a polarizer, an electro-optic crystal, and an analyzer, each located in said given path and arranged in the stated order in the direction of advancement of light along said path, and a quarter-wave plate located in said path between said polarizer and said analyzer, said electro-optic crystal consisting of a material having an optical rotatory power, said analyzer having its orientation rotated through an angle of approximately 45° relative to the optical axis of said electro-optic crystal, and the thickness of said electro-optic crystal in the direction of the advancement of light being given by the following equation: l≈45°/θ where θ represents the optical rotatory power, with respect to the applied light, of said electro-optic crystal near a point at the center of said given temperature range.
Claim 8
Dependent Claim
36 words
The combination of claim 5 wherein said electro-optic crystal consists of a material selected from the group consisting of bismuth silicon oxide (Bi 12 SiO 20 ) and bismuth germanium oxide (Bi 12 GeO 20 ).
Claim 9
Dependent Claim
32 words
The combination of claim 5 wherein the wavelength of the applied light is between 800 and 900 nm, and the thickness l of said electro-optic crystal is between 4.5 and 4.8 mm.
References Cited (Backward Citations)
US4269483A
Cited
US4465969A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-06 | 1989-07-08 | 1990-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-06 | 1993-07-08 | 1994-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-06 | 1997-07-08 | 1998-01-07 | $7700.00 | Window Closed / Lapsed |