US3620593A
Expired / Lapsed
US
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Method of surface interference microscopy
Assignee: American Optical Corp
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Filing: 1970-02-02
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Granted: 1971-11-16
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Expires: 1990-02-02
Abstract
Abstract An incident beam of natural light is divided into two beams of linear polarized light, their polarizations being mutually perpendicular. One beam is directed to a specimen surface and the other to a reference surface. Upon reflection from their respective surfaces, the beams are recombined and analyzed. The resultant of this recombined beam is a linear polarized beam having a certain orientation which is a function of the difference in optical path of the two beams. This optical path difference relates to the magnitude of imperfections of the specimen surface under observation.
Inventors
- 👤 Robert B Tackaberry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:40
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/06; G02B21/08; G02B21/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
173 words
A surface interference microscope including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light toward a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate and an objective disposed between said beam divider and said specimen surface in the path of said object beam directed to and reflected from said specimen surface, a quarter-wave retardation plate and objective disposed between said beam divider and said reference surface in the path of said reference beam directed to and reflected from said reference surface, said beam divider being operative to recombine said reflected object and reference beams, a quarter-wave retardation plate, an analyzer, and an eyepiece disposed in the path of said recombined beam, said analyzer being rotatable to determine a position at which the rate of change of transmittance therethrough with respect to the angular orientation of said analyzer is zero.
Claim 2
Dependent Claim
173 words
A surface interference microscope including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light toward a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate and an objective disposed between said beam divider and said specimen surface in the path of said object beam directed to and reflected from said specimen surface, a quarter-wave retardation plate and objective disposed between said beam divider and said reference surface in the path of said reference beam directed to and reflected from said reference surface, said beam divider being operative to recombine said reflected object and reference beams, a quarter-wave retardation plate, an analyzer, and an eyepiece disposed in the path of said recombined beam, said analyzer being rotatable to determine a position at which the rate of change of transmittance therethrough with respect to the angular orientation of said analyzer is zero.
Claim 3
Dependent Claim
247 words
A surface interference microscope including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light toward a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate to convert said object beam from linear to circular polarized light prior to incidence on said specimen surface and to convert said object beam from circular to linear polarized light after reflection from said specimen surface, an objective lens disposed in the path of said object beam, a quarter-wave retardation plate to convert said reference beam from linear to circular polarized light prior to incidence on said reference surface and to convert said reference beam from circular to linear polarized light after reflection from said reference surface, an objective lens disposed in the path of said reference beam, said reflected object and reference beams being directed to said beam divider to be recombined, a quarter-wave retardation plate disposed in the path of said recombined beam to convert its mutually perpendicular components to circular polarized components, the resultant of said circular polarized components being a linear polarized beam, an analyzer disposed in the path of said recombined beam to measure its orientation, said orientation being a function of the difference in optical path of said object and reference beams, and an eyepiece disposed in the path of said recombined beam.
Claim 4
Dependent Claim
247 words
A surface interference microscope including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light toward a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate to convert said object beam from linear to circular polarized light prior to incidence on said specimen surface and to convert said object beam from circular to linear polarized light after reflection from said specimen surface, an objective lens disposed in the path of said object beam, a quarter-wave retardation plate to convert said reference beam from linear to circular polarized light prior to incidence on said reference surface and to convert said reference beam from circular to linear polarized light after reflection from said reference surface, an objective lens disposed in the path of said reference beam, said reflected object and reference beams being directed to said beam divider to be recombined, a quarter-wave retardation plate disposed in the path of said recombined beam to convert its mutually perpendicular components to circular polarized components, the resultant of said circular polarized components being a linear polarized beam, an analyzer disposed in the path of said recombined beam to measure its orientation, said orientation being a function of the difference in optical path of said object and reference beams, and an eyepiece disposed in the path of said recombined beam.
Claim 5
Dependent Claim
215 words
An optical interferometry apparatus including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light towards a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate to convert said object beam from linear to circular polarized light prior to incidence on said specimen surface and to convert said object beam for circular to linear polarized light after reflection from said specimen surface, a quarter-wave retardation plate to convert said reference beam for linear to circular polarized light prior to incidence on said reference surface and to convert said reference beam for circular to linear polarized light after reflection from said reference surface, said reflected object and reference beams being directed to said beam divider to be recombined, a quarter-wave retardation plate disposed in the path of said recombined beam to convert its mutually perpendicular components to circular polarized components, the resultant of said circular polarized components being a linear polarized beam, and an analyzer disposed in the path of said recombined beam to measure its orientation, said orientation being a function of the difference in optical path of said object and reference beams.
Claim 6
Dependent Claim
215 words
An optical interferometry apparatus including: a polarizing beam divider disposed in the path of incident light, said beam divider directing an object beam of linear polarized light toward a specimen surface and a reference beam of linear polarized light towards a reference surface, the polarizations of said object and reference beams being mutually perpendicular, a quarter-wave retardation plate to convert said object beam from linear to circular polarized light prior to incidence on said specimen surface and to convert said object beam for circular to linear polarized light after reflection from said specimen surface, a quarter-wave retardation plate to convert said reference beam for linear to circular polarized light prior to incidence on said reference surface and to convert said reference beam for circular to linear polarized light after reflection from said reference surface, said reflected object and reference beams being directed to said beam divider to be recombined, a quarter-wave retardation plate disposed in the path of said recombined beam to convert its mutually perpendicular components to circular polarized components, the resultant of said circular polarized components being a linear polarized beam, and an analyzer disposed in the path of said recombined beam to measure its orientation, said orientation being a function of the difference in optical path of said object and reference beams.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |