US4997747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the formation of a diffraction grating
Assignee: Sharp Corp
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Filing: 1988-10-05
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Granted: 1991-03-05
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Expires: 2008-10-05
Abstract
Abstract A method for the formation of a diffraction grating on a substrate using a holographic technique and an etching technique, wherein the periodicity of the pattern of the diffraction grating can be changed at will by a change of the light-path length of one of the two light fluxes from a holographic exposing system.
Inventors
- 👤 Toshihiko Yoshida
- 👤 Haruhisa Takiguchi
- 👤 Shinji Kaneiwa
- 👤 Sadayoshi Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:53
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/12; G; G02; G02B; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857; G02B5/32; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/124; H01S5/124; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
150 words
A method for the formation of a diffraction grating on a substrate using a holographic technique and an etching technique, the method comprising the steps of: coating a photoresist on said substrate; forming interference fringes on said photoresist by superposing two light fluxes from a holographic exposing system on said photoresist, wherein a transparent board is placed in the path of one but not both of said two light fluxes so that a difference in light path length is created between a portion of said one light flux and the remaining portion; developing said photoresist to eliminate photosensitive areas thereon; etching said substrate using remaining photoresist as an etching mask; and removing said etching mask from said substrate, thus providing a diffraction grating on said substrate, whereby a phase shift is introduced at a discrete point within the diffraction grating as a result of said difference in light path length.
Claim 2
Independent Claim
150 words
A method for the formation of a diffraction grating on a substrate using a holographic technique and an etching technique, the method comprising the steps of: coating a photoresist on said substrate; forming interference fringes on said photoresist by superposing two light fluxes from a holographic exposing system on said photoresist, wherein a transparent board is placed in the path of one but not both of said two light fluxes so that a difference in light path length is created between a portion of said one light flux and the remaining portion; developing said photoresist to eliminate photosensitive areas thereon; etching said substrate using remaining photoresist as an etching mask; and removing said etching mask from said substrate, thus providing a diffraction grating on said substrate, whereby a phase shift is introduced at a discrete point within the diffraction grating as a result of said difference in light path length.
Claim 3
Dependent Claim
57 words
A method for the formation of a diffraction grating according to claim 1, wherein said transparent board has an uneven refractive index, and the difference in light path length of one of the two light fluxes from the holographic exposing system is achieved by passing said one light flux through said transparent board of uneven refractive index.
References Cited (Backward Citations)
DE1109448B
Cited
US3916182A
Cited
US4120559A
Cited
US4402571A
Cited
US4806454A
Cited
US4806442A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |