Phase retarder
CA 1307151 C · Owner: Nakamura, Kimishige · Inventors: Kikui, Hitoshi; Nakamura, Kimishige; Sakakura, Kazuaki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A phase retarder causing a retardation of 1/2.lambda. or .lambda. is disclosed, which is obtained by uniaxially stretching a polycarbonate film, whose retardation value ranges from about 200 nm to about 625 nm, preferably from about 200 nm to about 350 nm or from about 475 nm to about 625 nm and whose color difference .DELTA.E* is not more than 20 as measured under crossed nicols with the phase retarder being set in such a manner that the main optic axis thereof makes an angle of 45 degrees with the crossed nicols.
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 8, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 8, 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.
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.