Patent US4346996A successfully refreshed from Google Patents.
US4346996A
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US
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Standard reflective device
Assignee: Motors Liquidation Co
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Filing: 1980-10-23
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Granted: 1982-08-31
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Expires: 2000-10-23
Abstract
Abstract A reflecting standard for an optical apparatus comprises a semitransparent crystal or glass which reflects from its front surface a predetermined proportion of the incident light dependent upon the index of refraction at the wavelength of the incident light. The rear surface of the reflector is disposed at an angle to the front surface and is provided with an antireflecting coating to minimize reflection therefrom.
Inventors
- 👤 Carl E. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:05
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4785
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
102 words
A standard reflecting device for an optical apparatus comprising a wedge shaped element having a flat polished front surface for specular reflection of a predetermined fraction of radiation incident thereupon, and a rear surface inclined at an angle to the front surface and treated with an antireflection coating to minimize reflected radiation from the rear surface, the element being selected from the family of materials consisting of semitransparent crystals and glasses wherein for near normal incidence the reflected fraction substantially equals (n-1) 2 /(n+1) 2 where n is the index of refraction of the material at the wavelength of the incident radiation.
Claim 2
Dependent Claim
102 words
A standard reflecting device for an optical apparatus comprising a wedge shaped element having a flat polished front surface for specular reflection of a predetermined fraction of radiation incident thereupon, and a rear surface inclined at an angle to the front surface and treated with an antireflection coating to minimize reflected radiation from the rear surface, the element being selected from the family of materials consisting of semitransparent crystals and glasses wherein for near normal incidence the reflected fraction substantially equals (n-1) 2 /(n+1) 2 where n is the index of refraction of the material at the wavelength of the incident radiation.
References Cited (Backward Citations)
US2215211A
Cited
US4047032A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-30 | 1986-03-01 | 1986-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-30 | 1990-03-01 | 1990-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-30 | 1994-03-01 | 1994-08-31 | $7700.00 | Window Closed / Lapsed |