US3687555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric polarization analyzer
Assignee: Nikon Corp
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Filing: 1970-12-23
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Granted: 1972-08-29
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Expires: 1990-12-23
Abstract
Abstract Photoelectric polarization analyzer of this invention includes polarization system consisting of a linear polarizer or a polarizing orientation oscillating K.D.P. elements, quarter-wave plate and a compensator; an analyzer; another quarter-wave plate provided between the analyzer and a specimen; an electric device for separating two photoelectric signals converted by a photoelectric element from the light transmitted through said other quarter-wave plate into two electric control signals. In the prior art one of the control signals is used to rotate the polarization system for compensating the orientation of the specimen, and the other control signal is used for shifting the compensator for compensating the phase difference. However, in this invention a half-wave plate is interposed between the polarization system and is and the specimen rotatable in a plane perpendicular to the optic axis of the polarization system, and said one of the two signals is applied to the half-wave plate to rotate it instead of rotating the polarization system, which simplifies the structure.
Inventors
- 👤 Tadaaki Yamamoto
- 👤 Toshiyuki Kasai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:16
CPC Classifications
G; G01; G01J; G01J4/00; G01J4/04; G01N; G01N21/00; G01N21/17; G01N21/21; G01N21/211; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/0327
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
312 words
Photoelectric polarization analyzer for automatically measuring two polarization variables (orientation and phase difference) comprising in combination: an illuminating optical system (L); a linear polarizer (P) disposed serially along the optical axis of said illuminating system; means (X1, Q1) for modulating the orientation of the light passing through said linear polarizer; means (X2) for modulating a phase difference of the light passing through said linear polarizer; a phase difference compensator (C) disposed slidably in the normal direction to the optical axis of said illuminating system, the orientation of the principal axis of said phase difference compensator (C) being at 45* with respect to the optical axis of said polarizer; a half-wave plate (H) disposed rotatably in said optical path and behind said phase difference compensator; a specimen (S) disposed behind the half-wave plate at arbitral orientation; a first quater-wave plate (Q2) disposed behind the specimen, the orientation of the principal axis of the first quater-wave plate being at - 45* with respect to said linear polarizer; an analyzer (A) disposed behind the quater-wave plate, the principal axis of the analyzer being at 90* with respect to the principal axis of said linear polarizer; photoelectric conversion means for converting a photo-signal including two components modulated by said orientation and phase difference modulation means, respectively, into an electric signal including two electric modulation signal components; and an electric control means for dividing said electric signal into said two modulated components, one component thereof being modulated by the rotation of said half-wave plate (H) to compensate for the orientation of the specimen, and the other component being modulated by sliding said phase difference compensator (C), to compensate for the phase difference of the specimen, whereby the orientation and the phase difference of the specimen is automatically measured as the angle of rotation of said half-wave plate and the length of movement of said phase difference compensator.
Claim 2
Dependent Claim
312 words
Photoelectric polarization analyzer for automatically measuring two polarization variables (orientation and phase difference) comprising in combination: an illuminating optical system (L); a linear polarizer (P) disposed serially along the optical axis of said illuminating system; means (X1, Q1) for modulating the orientation of the light passing through said linear polarizer; means (X2) for modulating a phase difference of the light passing through said linear polarizer; a phase difference compensator (C) disposed slidably in the normal direction to the optical axis of said illuminating system, the orientation of the principal axis of said phase difference compensator (C) being at 45* with respect to the optical axis of said polarizer; a half-wave plate (H) disposed rotatably in said optical path and behind said phase difference compensator; a specimen (S) disposed behind the half-wave plate at arbitral orientation; a first quater-wave plate (Q2) disposed behind the specimen, the orientation of the principal axis of the first quater-wave plate being at - 45* with respect to said linear polarizer; an analyzer (A) disposed behind the quater-wave plate, the principal axis of the analyzer being at 90* with respect to the principal axis of said linear polarizer; photoelectric conversion means for converting a photo-signal including two components modulated by said orientation and phase difference modulation means, respectively, into an electric signal including two electric modulation signal components; and an electric control means for dividing said electric signal into said two modulated components, one component thereof being modulated by the rotation of said half-wave plate (H) to compensate for the orientation of the specimen, and the other component being modulated by sliding said phase difference compensator (C), to compensate for the phase difference of the specimen, whereby the orientation and the phase difference of the specimen is automatically measured as the angle of rotation of said half-wave plate and the length of movement of said phase difference compensator.
Claim 3
Dependent Claim
196 words
Photoelectric polarization analyzer according to claim 1, wherein said orientation modulation means comprises a first double refraction element (X1) disposed behind said linear polarizer (P) and having an electro-optical effect, the orientation of the principal axis of the first double refraction element being at 45* with respect to the principal axis of said linear polarizer, a second quater-wave plate (Q1) disposed between said first double refraction element and said phase difference modulation means, the orientation of the principal axis of the second quater-wave plate being at 0* or 90* with respect to the principal axis of said linear polarizer; an oscillator for applying an electric voltage to said first double refraction element; and said phase difference modulation means comprises a second double refraction element (X2) disposed between said second quater-wave plate and said phase difference compensator (C) and having an electro-optical effect, the orientation of the principal axis of the second refraction element (X2) being at 45* with respect to said linear polarizer, and an oscillator for applying to the second double refraction element (X2) an electric voltage whose phase differs by 90* from that of said voltage applied to said first double refraction element (X1).
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |