US5279924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacturing method of optical diffraction grating element with serrated gratings having uniformly etched grooves
Assignee: Sharp Corp
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Filing: 1992-07-01
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Granted: 1994-01-18
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Expires: 2012-07-01
Abstract
Abstract The method of manufacturing an optical diffraction grating element of the present invention is characterized in adopting an ion beam made from a gas chemically reacting with a glass substrate when forming a diffraction grating having a serrated profile upon the glass substrate through an ion beam etching method. Also, when manufacturing an optical diffraction grating element that is divided into a plurality of regions whereon diffraction gratings having different diffraction angles with respect to an incident light are provided, the method of the present invention is characterized in forming slits into a resist film disposed upon a transparent substrate such as a glass substrate, in accordance with the patterns of the diffraction gratings, such that the width of the slits is constant irrespectively of the regions. Accordingly, the method of manufacturing an optical diffraction grating element of the present invention enables to improve the diffraction efficiency of the optical diffraction grating element, and to enhance the optical efficiency of an optical head device. The SN ratio of the output signals released by the optical head device may be thus improved and the servo error control executed accurately.
Inventors
- 👤 Keiji Sakai
- 👤 Katsuhiro Kubo
- 👤 Yukio Kurata
- 👤 Takahiro Miyake
- 👤 Yoshio Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:03
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1353; G02; G02B; G02B5/00; G02B5/18; G02B5/1814; G02B5/1847; G02B5/1857; G02B5/1866; G02B5/1871
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
147 words
A method of manufacturing an optical diffraction grating element comprising: (a) forming a resist film upon a transparent substrate, wherein said resist film and substrate are divided into plurality of regions; (b) exposing and developing each of said plurality of regions in said resist film for forming a plurality of diffraction grating patterns corresponding to each of said plurality of regions having slits free of resist film; and (c) etching said resist film and said transparent substrate by irradiation of an ion beam upon a surface of said transparent substrate at a fixed angle, to form upon said transparent substrate a plurality of diffraction gratings having serrated profiles and mutually different diffraction angles with respect to an incident light, wherein said slits formed during said exposing and developing process are designed such as to have a substantially constant width irrespectively of said plurality of diffraction grating patterns.
Claim 2
Independent Claim
147 words
A method of manufacturing an optical diffraction grating element comprising: (a) forming a resist film upon a transparent substrate, wherein said resist film and substrate are divided into plurality of regions; (b) exposing and developing each of said plurality of regions in said resist film for forming a plurality of diffraction grating patterns corresponding to each of said plurality of regions having slits free of resist film; and (c) etching said resist film and said transparent substrate by irradiation of an ion beam upon a surface of said transparent substrate at a fixed angle, to form upon said transparent substrate a plurality of diffraction gratings having serrated profiles and mutually different diffraction angles with respect to an incident light, wherein said slits formed during said exposing and developing process are designed such as to have a substantially constant width irrespectively of said plurality of diffraction grating patterns.
Claim 3
Dependent Claim
92 words
The method of manufacturing an optical diffraction grating element as defined in claim 1, further comprising (d) the step of preparing a photomask provided with light transmitting parts and shadowing parts formed upon said substrate in accordance with said plurality of diffraction grating patterns such that a shadowing film is not disposed upon said substrate in said light transmitting parts, and said shadowing film is disposed upon said substrate in said shadowing parts; wherein the widths of said light transmitting parts are substantially equal in width irrespectively of said diffraction grating patterns.
Claim 4
Dependent Claim
69 words
The method of claim 2, wherein the width of some of the shadowing parts on the photomasks are not of equal width and the exposing step uses said photomask; the ion beam is directed to said substrate from one direction at an oblique angle; and a gas used which comprises the ion beam is a fluoride gas that reacts with the substrate to form curves in the serrated portions.
Claim 5
Dependent Claim
12 words
The method of claim 3, wherein the gas is CF 4 .
Claim 6
Dependent Claim
12 words
The method of claim 3, wherein the gas is CHF 3 .
Claim 7
Dependent Claim
14 words
The method of claim 3, wherein the gas is C 2 F 6 .
Claim 8
Dependent Claim
12 words
The method of claim 3, wherein the gas is NF 3 .
Claim 9
Dependent Claim
69 words
The method of claim 1, wherein resist films remain between the slits after the development process the width of some of the resist films are greater than others a gas which comprises the ion beam is directed to said substrate from an oblique angle from only one direction and the gas is a fluoride gas effective to chemically react with said substrate to form curves in the serrated profiles.
Claim 10
Dependent Claim
16 words
The method of claim 1, wherein a gas which comprises the ion beam CF 4 .
Claim 11
Dependent Claim
17 words
The method of claim 1, wherein a gas which comprises the ion beam is CHF 3 .
Claim 12
Dependent Claim
19 words
The method of claim 1, wherein a gas which comprises the ion beam is C 2 F 6 .
Claim 13
Dependent Claim
17 words
The method of claim 1, wherein a gas which comprises the ion beam is NF 3 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-17 | 1997-07-19 | 1998-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-17 | 2001-07-19 | 2002-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-17 | 2005-07-19 | 2006-01-18 | $7700.00 | Window Closed / Lapsed |