Display device
CA 2005403 C · Owner: Coulson, Ian · Inventors: Coulson, Ian
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A ferroelectric liquid crystal device has a first state (TX1) of maximum transmission, a second state (TX2) of minimum transmission and a value of voltage pulse width (tg) and voltage pulse height (VS) sufficient for a switching pulse to switch the cell from the first state (TX1) to the second state (TX2) or vice verse. A method of controlling the transmission of electromagnetic radiation through the ferroelectric liquid crystal device comprises the step of applying, for a time period greater than said value of pulse width (tS), a plurality of consecutive controlling pulses of one polarity. Each controlling pulse is itself of insufficient pulse height and pulse width to switch the cell from …
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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 December 13, 1989 and granted June 8, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 13, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 13, 2011.
- 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.