Method and apparatus for fabricating very small two-colour balls for a twisting ball display
CA 2257757 C · Owner: Richley, Edward A. · Inventors: Richley, Edward A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A bichromal ball includes a first hemisphere. The first hemisphere includes a first pigment having a first color and a first polarity. The first pigment is added to a carrier fluid and polymer mixture during formation of the bichromal ball. A second hemisphere includes a second pigment having a second color and a second polarity. The second pigment is added to the carrier fluid and polymer mixture during formation of the bichromal ball. The carrier fluid and polymer mixture have a lower viscosity than the polymer alone. The carrier fluid is substantially removed after the first and second hemispheres are formed. The polymer is left along with the first and second pigments which form the …
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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 January 4, 1999 and granted April 30, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 4, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 4, 2021.
- 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.