Optical system
CA 1109961 A · Owner: Hitachi, Ltd. · Inventors: Kataoka, Keiji; Yonezawa, Seiji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical system had an objective lens for focussing on a dotted information carrying video disc the light emitted from a light source of semiconductor laser whose radiant region has different longitudinal and lateral dimensions, and a coupling lens disposed between the objective lens and the laser source for condensing the light from the laser source. The coupling lens has a magnification factor of not greater than 7.
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 September 29, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 29, 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.