High temperature lamps having uv absorbing quartz envelope
CA 2087778 C · Owner: Parham, Thomas Gene · Inventors: Mathews, Paul G.; Bateman, Robert L. Jr.; Allen, Gary R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Fused quartz containing both titanium dioxide and cerium oxide as UV absorbing dopants has been found to be particularly effective for lamp envelopes for high temperature lamps such as, halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation. The codoped quartz transmits visible radiation and absorbs a substantial portion of the emitted UV radiation. The UV absorption is far superior at temperatures above 500°C and the codoped quartz does not react with the fill within.
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 21, 1993 and granted August 24, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 21, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 21, 2015.
- 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.