Laser optical pickup apparatus
CA 2008593 C · Owner: Kurata, Yukio · Inventors: Yoshida, Yoshio; Miyake, Takahiro; Nishitani, Yukinori
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical pickup apparatus for reading out information from an optical disk includes a light source; and an optical device having a grating pattern for splitting a light beam from the source into a zero-order diffracted beam and plus and minus first-order diffracted beams. The grating pattern has the center portion and one or more side portions. The efficiency of the center portion for the zero-order diffracted beam is greater than the efficiency of the side portions for the zero-order diffracted beam.
Read the whole patent
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 25, 1990 and granted October 4, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 25, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 25, 2012.
- 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
Timeline From CIPO dates
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.