Apparatus for reading a radiation-reflecting record carrier
CA 1107395 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Bouwhuis, Gijsbertus
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus is described for reading a record carrier with an optical information structure in, which apparatus errors in the focussing of a read beam on the information plane are detected with an astigmatic focussing-error detection system. By including a beam splitter in the path of a beam which has been reflected by the record carrier and by including an astigmatic focussing-error detection system in each of the paths of the two sub-beams thus obtained, the astigmatism of the one detection system being opposed to that of the other detection system a focus-, sing-error signal can be derived which is independent of optical faults in the road apparatus.
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 August 18, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 18, 1998.
- 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.