Prism and method of producing the same
CA 2478641 A1 · Owner: Takeuchi, Hirokazu · Inventors: Seto, Tadashi; Takeuchi, Hirokazu; Nakajima, Nagaharu
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In the prism of the invention, the Ra value is less than the value corresponding to #170 for a surface that serves as a light incidence surface after forming, and a glass parent material having a predetermined size ratio is gripped by a feed means and fed into a furnace where it is heated to a , temperature such that the lowest viscosity is not less than 104 Pa.cndot.s but less than 106 Pa.cndot.s, the lower portion being stretch-formed by a stretch means and cut into long bodies having a desired size and an incident light surface whose surface Ra value is not more than 1/4 of the incident light wavelength, and then such long body being cut into pieces of desired length thus …
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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 March 5, 2003. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 5, 2023.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 5, 2025.
- 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.