Focusing-type calculating means
CA 2236772 C · Owner: Liu, Yu Shian · Inventors: Lu, Shu Fang; Wang, Ching Shun; Hsieh, Cheng-Liang
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A focusing-type calculating device comprising a light source, a grating wheel, and a photo-detector. The input plane of the grating wheel has a ring-shaped lens to focus the light emitted from the light source. The output plane of the grating wheel has a plurality of tooth-shaped lenses perpendicular to the ring-shaped lens, which can focus the working beams after the working beams pass through the output plane, thus minimizing interference. The device can be used for detecting the position, speed and acceleration of a moving or rotating object such as a computer mouse.
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
- Filed June 2, 1998 and granted July 29, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 2, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 2, 2020.
- 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.