US3843239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase shifting plate having uniform transmittance
Assignee: Hitachi Ltd
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Filing: 1973-05-15
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Granted: 1974-10-22
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Expires: 1993-05-15
Abstract
Abstract An optical phase shifting plate, for use with a holographic apparatus, comprises a transparent base, a first thin transparent film of a uniform thickness formed thereupon, and a second thin transparent film formed upon the first thin film for effecting two-dimensionally non-uniform phase shifting, the thickness of the first and second thin films being so determined that a uniform distribution of intensity of transmitted light may be obtained.
Inventors
- 👤 Y Tsunoda
- 👤 Y Miyamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:56
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
144 words
A phase shifting plate comprising: a transparent base; a first thin transparent film formed with a uniform thickness upon said transparent base; and a second thin transparent film with a predetermined pattern formed upon said first thin transparent film; the thicknesses of said first and second thin transparent films being so determined that the intensity of light transmitted through said phase shifting plate may be uniformly distributed over the whole surface thereof, wherein the thicknesses of said first and second thin transparent films are so selected as to satisfy the following relationships: d lambda /2 ( n - 1 ) , and d1 lambda /4n ( m - n/n - 1 ) > 0 where d1, d thicknesses of the first and second thin transparent films, respectively, n index of refraction of said films, lambda wavelength of incident light, and m a positive integer.
Claim 2
Dependent Claim
144 words
A phase shifting plate comprising: a transparent base; a first thin transparent film formed with a uniform thickness upon said transparent base; and a second thin transparent film with a predetermined pattern formed upon said first thin transparent film; the thicknesses of said first and second thin transparent films being so determined that the intensity of light transmitted through said phase shifting plate may be uniformly distributed over the whole surface thereof, wherein the thicknesses of said first and second thin transparent films are so selected as to satisfy the following relationships: d lambda /2 ( n - 1 ) , and d1 lambda /4n ( m - n/n - 1 ) > 0 where d1, d thicknesses of the first and second thin transparent films, respectively, n index of refraction of said films, lambda wavelength of incident light, and m a positive integer.
Claim 3
Dependent Claim
30 words
A phase shifting plate as defined in claim 1, wherein said predetermined pattern of said second thin transparent film is irregular, so that the transmitted light rays have random phases.
Claim 4
Dependent Claim
23 words
A phase shifting plate as defined in claim 1, wherein both of said thin transparent films are made of ZnS and m 5.
Claim 5
Dependent Claim
23 words
A phase shifting plate as defined in claim 1, wherein both of said thin transparent films are made of CeF, and m 7.
Claim 6
Dependent Claim
30 words
A phase shifting plate as defined in claim 1, wherein said first and second thin transparent films are made of the same material and have the same index of refraction.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |