US4072423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light interference device with low degree of spacial coherence
Assignee: Konica Minolta Inc
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Filing: 1976-01-16
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Granted: 1978-02-07
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Expires: 1996-01-16
Abstract
Abstract A light interference device comprising a light source having a low degree of spacial coherence, an optical element having a reference surface for interference, an optical system for providing a parallel light bundle, and an optical projection system for projecting interference fringes localized near the interference surface. Said parallel light bundle comes out of the reference surface at an angle θ within the range of 0° < θ ≦ 30°.
Inventors
- 👤 Yoshiaki Kimura
- 👤 Hiroshi Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:13
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02; G01B11/00; G01B11/30; G01B11/306
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
193 words
A light interference device for measuring the flatness of a surface to be measured, said surface to be measured being one side of a plate of transparent material having a back face, said device comprising a light source, an optical element having a reference surface for interference upon which a parallel light bundle from the light source impinges and passes through and from which a parallel light bundle is reflected, said reference surface being locatable adjacent but spaced from said surface to be measured whereby interference fringes are generated as a result of the interaction of light rays reflected from said reference surface and from said surface to be measured, said light source having a low degree of spatial coherence whereby said interference fringes are localized near said interference surface, an optical system between said light source and said reference surface for providing a parallel light bundle coming out from said reference surface toward said surface to be measured at an angle θ within the range of 0° < θ ≦ 30°, an observing surface, and an optical projection system for projecting interference fringes localized near said interference surface onto said observing surface.
Claim 2
Dependent Claim
193 words
A light interference device for measuring the flatness of a surface to be measured, said surface to be measured being one side of a plate of transparent material having a back face, said device comprising a light source, an optical element having a reference surface for interference upon which a parallel light bundle from the light source impinges and passes through and from which a parallel light bundle is reflected, said reference surface being locatable adjacent but spaced from said surface to be measured whereby interference fringes are generated as a result of the interaction of light rays reflected from said reference surface and from said surface to be measured, said light source having a low degree of spatial coherence whereby said interference fringes are localized near said interference surface, an optical system between said light source and said reference surface for providing a parallel light bundle coming out from said reference surface toward said surface to be measured at an angle θ within the range of 0° < θ ≦ 30°, an observing surface, and an optical projection system for projecting interference fringes localized near said interference surface onto said observing surface.
Claim 3
Dependent Claim
38 words
A light interference device according to claim 1, wherein said light source comprises a laser, a condenser for focusing the laser beam from the laser and a rotary diffusing plate located near the focusing point of the condenser.
Claim 4
Dependent Claim
30 words
A light interference device according to claim 1, wherein said optical system comprises a collimator lens for converting a light bundle from said light source to a parallel light bundle.
Claim 5
Dependent Claim
29 words
A light interference device according to claim 1, wherein said optical element is a glass block having the reference surface and a surface inclinedly opposing to said reference surface.
Claim 6
Dependent Claim
43 words
A light interference device according to claim 1, wherein said optical projection system includes an optical member comprising a lens and a mirror, and a mask provided with a minute aperture and located at the focusing point provided by the inmirror optical system.
Claim 7
Dependent Claim
36 words
A light interference device according to claim 2, wherein said optical projection system includes a collimator lens and a mask provided with a minute aperture and located at the focusing point provided by the collimator lens.
References Cited (Backward Citations)
US2518647A
Cited
US3941456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |