EP0428390A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Manufacturing method of optical diffraction grating element
Assignee: Sharp Corp
•
Filing: 1990-11-13
•
Granted: —
•
Expires: 2010-11-13
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
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 19:01
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
98 words
A method of manufacturing an optical diffraction grating element comprising: a first process of forming a resist film upon a glass substrate; a second process of exposing and developing said resist film to form a diffraction grating pattern; and a third process of etching said resist film and said glass substrate by slantwise irradiation of an ion beam upon a surface of said glass substrate to form a diffraction grating having a serrated profile upon said glass substrate, wherein said ion beam employed in said third process is made from a gas chemically reacting with said glass substrate.
Claim 2
Independent Claim
98 words
A method of manufacturing an optical diffraction grating element comprising: a first process of forming a resist film upon a glass substrate; a second process of exposing and developing said resist film to form a diffraction grating pattern; and a third process of etching said resist film and said glass substrate by slantwise irradiation of an ion beam upon a surface of said glass substrate to form a diffraction grating having a serrated profile upon said glass substrate, wherein said ion beam employed in said third process is made from a gas chemically reacting with said glass substrate.
Claim 3
Independent Claim
126 words
A method of manufacturing an optical diffraction grating element comprising: a first process of forming a resist film upon a transparent substrate; a second process of exposing and developing said resist film in accordance with a plurality of diffraction grating patterns, to form slits free of resist film; and a third process of etching said resist film and said transparent substrate by slantwise irradiation of an ion beam upon a surface of said transparent substrate, 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 second process are designed such as to have a substantially constant width irrespectively of said plurality of diffraction grating patterns.
Claim 4
Independent Claim
126 words
A method of manufacturing an optical diffraction grating element comprising: a first process of forming a resist film upon a transparent substrate; a second process of exposing and developing said resist film in accordance with a plurality of diffraction grating patterns, to form slits free of resist film; and a third process of etching said resist film and said transparent substrate by slantwise irradiation of an ion beam upon a surface of said transparent substrate, 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 second process are designed such as to have a substantially constant width irrespectively of said plurality of diffraction grating patterns.
Claim 5
Dependent Claim
23 words
A method of manufacturing an optical diffraction grating element as defined in claim 1, wherein said gas is CF₄, CHF₃, C₂F₆, or NF₃.
Claim 6
Dependent Claim
123 words
A method of manufacturing an optical diffraction grating element as def ined in claim 2, further comprising a process of preparing a photomask provided with light transmitting parts and shadowing parts formed upon a 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 said shadowing parts are designed such that the greater grating pitches of said diffraction grating patterns are, the wider a width of each of said shadowing parts is, and said light transmitting parts are designed such as to have a substantially constant width irrespectively of said diffraction grating patterns.
Claim 7
Independent Claim
69 words
A method of manufacturing a diffraction grating element comprising the steps: forming on a substrate a resist film having a predetermined pattern; and etching said resist film and said substrate by irradiation by an ion beam incident at an angle to the normal of the substrate to form a diffraction grating having a serrated profile; characterised in that the ion beam comprises a gas chemically reactive with the substrate.
Claim 8
Independent Claim
69 words
A method of manufacturing a diffraction grating element comprising the steps: forming on a substrate a resist film having a predetermined pattern; and etching said resist film and said substrate by irradiation by an ion beam incident at an angle to the normal of the substrate to form a diffraction grating having a serrated profile; characterised in that the ion beam comprises a gas chemically reactive with the substrate.
Claim 9
Dependent Claim
54 words
A diffraction grating element having a serrated profile including a plurality of groove portions the serrated profile comprising first regions of a first pitch and second regions of a second pitch characterised in that the groove portions of the first region and the groove portions of the second region have substantially the same configuration.
Claim 10
Dependent Claim
54 words
A diffraction grating element having a serrated profile including a plurality of groove portions the serrated profile comprising first regions of a first pitch and second regions of a second pitch characterised in that the groove portions of the first region and the groove portions of the second region have substantially the same configuration.
Claim 11
Dependent Claim
111 words
A method of manufacturing a diffraction grating element according to claim 6 comprising the steps: forming a resist film on a substrate, the resist film having a first pattern region for forming the first region of the serrated profile and a second pattern region for forming the second region of the serrated profile; and etching said resist film and said substrate by irradiation by an ion beam incident at an angle to the normal of the substrate to form the diffraction grating element, characterised in that both the first and second pattern regions include regions free from resist film, these regions free of resist film being of substantially the same width.
Claim 12
Dependent Claim
12 words
A method according to claim 7 wherein the ion beam comprises argon.
Claim 13
Dependent Claim
26 words
A method according to claim 7 wherein the substrate is glass and the ion beam comprises a gas from the group CF₄, CHF₃, C₂F₆, and NF₃.
Claim 14
Independent Claim
91 words
A method according to any one of claims 7 to 9 wherein the step of forming a resist film on a substrate comprises the steps of: preparing a photomask having light transmitting regions corresponding to the regions free from resist film and opaque regions spanning the spaces between adjacent light transmitting regions formed on a substrate in accordance with the first and second patterns, wherein each of the light transmitting regions is of substantially the same width, exposing the resist film through the photo mask, and developing the exposed resist film.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.