Patent Yard Sign in
Expired Canadian patentCanada

Optical image rotators

CA 1302138 C · Owner: Keens, Andrew Peter · Inventors: Keens, Andrew Peter

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

Open the CIPO record

Abstract From the Canadian patent

An optical rotator such as a Pechan rotator is arranged to rotate an image about a given axis. Light entering an input surface of the rotator is subjected to a number (e.g. five) of reflections, alternate reflections being total internal reflections and the intervening ones being mirror reflections. At least one of the surfaces preferably one at which total, internal reflection occurs bears a layered polarising material, arranged to impart a defined polarisation effect as between light entering and exiting the rotator.

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 June 2, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 2, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 2, 1988
GrantedJune 2, 1992
Term endedJune 2, 2009
Patent numberCA 1302138 C
Classification (IPC)G02B26/08 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedSep 2, 1988Patent grantedJune 2, 1992Term endedJune 2, 2009

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.