Method and master for making a color selection mask for a color cathode ray tube
CA 1074171 A · Owner: Zenith Radio Corporation · Inventors: Lange, Howard G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus and method for use in producing the illumination pattern and the pattern of electron-transmissive apertures in a color selection mask for a color cathode ray tube. The apparatus comprises a rigid transparent substrate which has, a first preselected optical density pattern of light-transmissive openings having substantially the same distribution as the first pattern but each opening having a second pattern of openings effectively establish upon a single exposure of a photoresist coated mask blank a double image exposure of the photoresist coating, the first image corresponding to the first pattern of openings. Each of the respective images is further capable of being separately …
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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
- Granted March 25, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 25, 1997.
- 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.