US3740150A
Expired / Lapsed
US
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Surface measurement by interferometer
Assignee: Tropel Inc
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Filing: 1971-01-06
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Granted: 1973-06-19
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Expires: 1991-01-06
Abstract
Abstract An interferometer measures a test surface arranged in the test arm of the interferometer by using a focusing lens system movable along the test arm. The focusing lens system is adjustable along a slide that is movable along the test arm of the instrument, and the test surface is mounted at a region of maximum coherence function of the test beam. The focusing lens system is adjusted along the slide to focus the test beam on the surface of the test surface. Then by means of gauge blocks removably interposable between the slide and a reference surface and equalling the desired radius of curvature of the test surface, the slide is moved to bring the focus of the test beam to the region of the center of curvature of the test surface to observe interference fringes between light returning from the test surface and a plane wave front reference beam.
Inventors
- 👤 C Munnerlyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:11
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/24; G01B11/255; G01B9/00; G01B9/02; G01B9/02055; G01B9/02062; G01B9/02063
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
149 words
An interferometer for measuring a test surface, said interferometer comprising: a. a mount for supporting said test surface in the test arm of said interferometer; b. a focusing lens system in said test arm of said interferometer; c. a slide carrying said focusing lens system; d. means for moving said slide a substantial distance along said test arm without moving said mount or the rest of said interferometer; e. means for adjusting the position of said focusing lens system throughout a substantial range along the length of said slide in the direction of said test arm; and f. means for positioning said slide quickly and accurately between two positions spaced apart along said test arm by the desired radius of curvature of said test surface, said focusing lens system in one of said positions being spaced from said test surface by the focal distance of said focusing lens system.
Claim 2
Dependent Claim
149 words
An interferometer for measuring a test surface, said interferometer comprising: a. a mount for supporting said test surface in the test arm of said interferometer; b. a focusing lens system in said test arm of said interferometer; c. a slide carrying said focusing lens system; d. means for moving said slide a substantial distance along said test arm without moving said mount or the rest of said interferometer; e. means for adjusting the position of said focusing lens system throughout a substantial range along the length of said slide in the direction of said test arm; and f. means for positioning said slide quickly and accurately between two positions spaced apart along said test arm by the desired radius of curvature of said test surface, said focusing lens system in one of said positions being spaced from said test surface by the focal distance of said focusing lens system.
Claim 3
Dependent Claim
22 words
The interferometer of claim 1 wherein said positioning means comprises gauge blocks removably interposable between said slide and a fixed reference surface.
Claim 4
Dependent Claim
15 words
The interferometer of claim 2 including means for biasing said slide toward said reference surface.
Claim 5
Dependent Claim
27 words
The interferometer of claim 2 wherein said slide includes an abutment arranged so other gauge blocks are removably interposable between said abutment and said focusing lens system.
Claim 6
Dependent Claim
26 words
The interferometer of claim 1 wherein said test surface is arranged at a region of maximum coherence function of the light beam in said test arm.
Claim 7
Dependent Claim
36 words
The interferometer of claim 2 wherein said test surface is arranged at a region of maximum coherence function of the light beam in said test arm, and said focusing lens system produces a spherical wave front.
Claim 8
Dependent Claim
34 words
The interferometer of claim 6 wherein said slide is biased toward said reference surface and includes an abutment arranged so other gauge blocks are removably interposable between said abutment and said focusing lens system.
Claim 9
Dependent Claim
131 words
An optical surface-measuring method comprising: a. arranging a test surface to be measured in the test arm of an interferometer; b. adjusting the position of a movable focusing lens system along said test arm to focus test beam light at a point on said test surface; c. moving said focusing lens system along said test arm for a distance from said position equal to the desired radius of curvature of said test surface to move said test beam light focus to the region of the center of curvature of said test surface; and d. observing interference fringes between light returning from said test surface and a plane wave front reference beam to determine the deviation of the actual radius of curvature of said test surface from said desired radius of curvature.
Claim 10
Dependent Claim
131 words
An optical surface-measuring method comprising: a. arranging a test surface to be measured in the test arm of an interferometer; b. adjusting the position of a movable focusing lens system along said test arm to focus test beam light at a point on said test surface; c. moving said focusing lens system along said test arm for a distance from said position equal to the desired radius of curvature of said test surface to move said test beam light focus to the region of the center of curvature of said test surface; and d. observing interference fringes between light returning from said test surface and a plane wave front reference beam to determine the deviation of the actual radius of curvature of said test surface from said desired radius of curvature.
Claim 11
Dependent Claim
27 words
The method of claim 8 including using gauge blocks equal to said desired radius of curvature for setting said distance of motion of said focusing lens system.
Claim 12
Dependent Claim
24 words
The method of claim 9 including removably interposing said gauge blocks between a fixed reference surface and a slide carrying said focusing lens system.
Claim 13
Dependent Claim
19 words
The method of claim 10 wherein said focusing adjustment includes positioning said focusing lens system along said slide line.
Claim 14
Dependent Claim
30 words
The method of claim 8 including adjusting said test surface after said movement of said focusing lens system to minimize said interference fringes to reveal unevenness of said test surface.
Claim 15
Dependent Claim
21 words
The method of claim 8 including arranging said test surface at a region of maximum coherence function of said test beam.
Claim 16
Dependent Claim
34 words
The method of claim 8 wherein said focusing adjustment includes coarse adjustment by positioning said focusing lens system on a slide movable along said test arm, and fine adjustment by positioning said test suRface.
Claim 17
Dependent Claim
21 words
The method of claim 14 including positioning said test surface to produce linear fringes used to make said fine focusing adjustment.
Claim 18
Dependent Claim
43 words
The method of claim 8 including arranging said test surface at a region of maximum coherence function of said test beam and using gauge blocks equal to said desired radius of curvature for setting said distance of motion of said focusing lens system.
Claim 19
Dependent Claim
38 words
The method of claim 16 including removably interposing said gauge blocks between a fixed reference surface and a slide carrying said focusing lens system, and wherein said focusing adjustment includes positioning said focusing lens system along said slide.
Claim 20
Dependent Claim
50 words
The method of claim 17 including refining said focusing adjustment by positioning said test surface to produce linear fringes, and arranging said test surface so said observed fringes are round after said motion of said test beam focus to the region of the center of curvature of said test surface.
Claim 21
Dependent Claim
40 words
The method of claim 18 including counting said round fringes to measure the actual radius of curvature of said test surface, and then adjusting said test surface to minimize said round fringes to reveal any unevenness of said test surface.
References Cited (Backward Citations)
US3512891A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |