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US6117346A
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Process for forming a microstructure in a substrate of a ferroelectric single crystal
Assignee: Ineos Fluor Holdings Ltd
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Filing: 1998-03-03
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Granted: 2000-09-12
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Expires: 2018-03-03
Abstract
Abstract A process for forming a microstructure at a surface of a substrate made of a ferroelectric single crystal, includes the steps of subjecting the substrate to a single-poling treatment, thereby one of an etching-easy surface and an etching-difficult surface being exposed to one of main faces of the substrate, while the other being exposed to the other main face, forming a domain-inverted region in at least one of the main faces of the substrate, and forming the microstructure at the substrate in the domain-inverted region of the substrate by selectively etching the substrate.
Inventors
- 👤 Tatsuo Kawaguchi
- 👤 Minoru Imaeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:04
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/355; G02F1/3558; C; C30; C30B; C30B29/00; C30B29/10; C30B29/16; C30B29/22; C30B29/30; C30B33/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
140 words
A process for forming a ridged optical waveguide layer at a surface of a substrate made of a ferroelectric single crystal, said process comprising the steps of: subjecting the substrate to a single-poling treatment, thereby exposing at least one of an etching-easy surface and an etching-difficult surface to one of the main faces of the substrate, while exposing the other of said at least one of an etching-easy surface and an etching-difficult surface to the other main face of said substrate; forming a domain-inverted region in at least one of the main faces of the substrate, wherein said etching-difficult surface is exposed at the domain-inverted region in one of the main faces of the ferroelectric single crystal substrate; and forming said ridged optical waveguide layer at the substrate in the domain-inverted region of the substrate by selectively etching the substrate.
Claim 2
Dependent Claim
140 words
A process for forming a ridged optical waveguide layer at a surface of a substrate made of a ferroelectric single crystal, said process comprising the steps of: subjecting the substrate to a single-poling treatment, thereby exposing at least one of an etching-easy surface and an etching-difficult surface to one of the main faces of the substrate, while exposing the other of said at least one of an etching-easy surface and an etching-difficult surface to the other main face of said substrate; forming a domain-inverted region in at least one of the main faces of the substrate, wherein said etching-difficult surface is exposed at the domain-inverted region in one of the main faces of the ferroelectric single crystal substrate; and forming said ridged optical waveguide layer at the substrate in the domain-inverted region of the substrate by selectively etching the substrate.
Claim 3
Dependent Claim
18 words
The process set forth in claim 1, wherein said microstructure is to be used as an optical element.
Claim 4
Dependent Claim
43 words
The process set forth in claim 1, wherein an etching-easy face is exposed at the domain-inverted region in one of the main faces of the ferroelectric single crystal substrate, and a recess is formed in the domain-inverted region by selectively etching the substrate.
Claim 5
Dependent Claim
41 words
The process set forth in claim 3, wherein an optical waveguide layer is formed in said recess, said optical waveguide layer being comprised of a ferroelectric single crystal having a refractive index larger than that of said ferroelectric single crystal substrate.
Claim 6
Dependent Claim
33 words
The process set forth in claim 1, wherein the ridged optical waveguide layer is located on a projected portion of the domain-inverted region, wherein said projected portion includes at least one concave surface.
Claim 7
Dependent Claim
76 words
The process set forth in claim 1, wherein the ferroelectric single crystal substrate is composed of one compound selected from the group consisting of LiNbO 3 , LiTaO 3 , a lithium niobate-lithium tantalate solid solution, K 3 Li 2 Nb 5 O 15 , K 3 Li 2 (Nb,Ta) 5 O 15 and these compounds in which at least one element selected from the group consisting of rare earth elements, magnesium and zinc is incorporated.
Claim 8
Dependent Claim
57 words
The process set forth in claim 1, wherein the domain-inverted region is formed by one method selected from the group consisting of an electric voltage-applying method, an electron beam scanning method, a proton-exchange heat treatment method, a titanium thermal oxidation method, a titanium indiffusion method, an Li 2 O outdiffusion method, and an SiO 2 cladding/annealing method.
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) | 2003-09-12 | 2004-03-13 | 2004-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-09-12 | 2008-03-13 | 2008-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-09-12 | 2012-03-13 | 2012-09-12 | $7700.00 | Window Closed / Lapsed |