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US4759607A
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Phase gratings of a combination pattern-refraction modification type
Assignee: Toshiba Corp
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Filing: 1986-10-21
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Granted: 1988-07-26
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Expires: 2006-10-21
Abstract
Abstract A combination pattern-refraction modification type phase grating comprises dual grating elements which are regularly arranged and each includes convex and concave portions which have respectively different thickness and are formed of material respectively different in refractive index so as to combine respective characteristics of a pattern and a refraction modification type phase grating.
Inventors
- 👤 Nobuhiko Kawatsuki
- 👤 Masao Uetsuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:58
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871; G02B5/1847; G02B5/1857
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
54 words
A phase grating of a combination pattern-refraction modification type comprises: dual grating elements including convex and concave portions of thin layers, said portions having different thicknesses, being regularly arranged and being formed of materials different in refractive index so as to provide a difference in refractive index between the convex and the concave portions.
Claim 2
Dependent Claim
54 words
A phase grating of a combination pattern-refraction modification type comprises: dual grating elements including convex and concave portions of thin layers, said portions having different thicknesses, being regularly arranged and being formed of materials different in refractive index so as to provide a difference in refractive index between the convex and the concave portions.
Claim 3
Dependent Claim
35 words
A phase grating according to claim 1, in which the refractive index of material forming the convex portion of the dual grating elements is higher than the refractive index of material forming the concave portion.
Claim 4
Dependent Claim
29 words
A phase grating according to claim 1 or 2, in which the convex portion of the dual grating elements is formed in the shape of a square in section.
Claim 5
Dependent Claim
36 words
A phase grating according to claim 1 or 2, in which the convex portion of the dual gratings is formed in the shape of one of a triangle, a trapezoid and a sinusoidal wave in section.
Claim 6
Dependent Claim
27 words
A phase grating according to claim 1 or 2, in which the difference in level between the convex and the concave portions is 0.001 μm or more.
Claim 7
Dependent Claim
27 words
A phase grating according to claim 1 or 2, in which the difference in refractive index between the convex and the concave portions is 0.005 or more.
Claim 8
Dependent Claim
24 words
A phase grating according to claim 6, in which the difference in level between the convex and concave portions is 0.001 um or more.
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) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |