Master plate of optical memory device and manufacturing method thereof
CA 2087108 C · Owner: Sharp Kabushiki Kaisha · Inventors: Mieda, Michinobu; Hirokane, Junji; Ohta, Kenji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A master plate of an optical memory device has a substrate having on a surface thereof a plurality of guiding grooves with a predetermined interval. The respective edge portions of the guiding grooves are inclined with respect to the surface of the substrate at an angle not more than 30°. According to a manufacturing method for the master plate the, post-baking process is carried out at a baking temperature of not less than 150°C, and an etching gas containing °2 gas of 4 (SCCM) to 10 (SCCM) is used. Thus, even when the copying is carried out with respect to the substrate of the optical memory device according to the injection molding process wherein the, stamper used is manufactured based …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed January 12, 1993 and granted February 16, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 12, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 12, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.