Optical pickup apparatus
CA 1324516 C · Owner: Sharp Kabushiki Kaisha · Inventors: Kurata, Yukio; Yoshida, Yoshio; Nagahama, Toshiya
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical pickup apparatus is disclosed for reproducing information from an optical recording medium such as a compact disc. The apparatus includes a laser device; one or more diffraction devices; and a photodetector receiving a laser beam diffracted by the diffraction device. The surfaces of the diffraction device are provided with an antireflection coating. When the apparatus is used for the three-beam method of information reproduction, the two photodetecting areas in the photodetector for producing the tracking error signal are different in size or in the positional relation with the laser device.
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
- Granted November 23, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 23, 2010.
- 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.