Keratometer having photographically produced bore pattern
CA 2173344 C · Owner: Maus, Roy · Inventors: Tibbling, Lars; Maus, Roy
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improved conical keratometer (10), wherein the parent image of the pattern to be reflected upon a target positioned adjacent to the illuminated bore is recorded on a film slide (40) retained within the keratometer bore (12). Opposite edges (51, 52) of the slide (40) are chamfered at equal but opposite angles so that, when the spindeled slide is released) the chamfered edges (51, 52) will meet along a line of contact rather than butting squarely together. The film slide (40) is rolled so that the emulsion side (53) is toward the periphery of the cone bore (12) and the chamfering allows that side to lie smoothly against the cone bore (12) without any gaps so that an undistorted image may …
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 January 23, 1995 and granted July 13, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 23, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 23, 2017.
- 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.