Contrast chart apparatus, contrast sensitivity measuring apparatus, and contrast sensitivity measuring method
CA 2438109 A1 · Owner: Hirohara, Yoko · Inventors: Mihashi, Toshifumi; Hirohara, Yoko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A contrast chart apparatus includes a contrast index showing block for showing at a predetermined timing a contrast index for checking the contrast sensitivity, a pupil data measuring block for forming an image in front of the eyes of a person to be tested and measuring the pupil diameter of the eyes a , measurement timing forming block for forming in accordance with the aforementioned timing, a measurement timing of the pupil data measurement block.
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 February 7, 2002. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 7, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 7, 2024.
- 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.