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CA 1210133 A · Owner: British Library Board (The) · Inventors: Wilman, Hugh; Brotton, James
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The state of focus of an image of a document is converted into a video signal by sequentially inspecting the incident light level at points within the image and generating an electrical signal having a parameter which varies with the light level. A device for achieving this result includes a circuit responsive to the electrical signal from sequential inspection of the image for integrating amplitude variations thereof to produce a varying amplitude focus indication signal. An indicator comprises a linear array of lamps the, operating current for the lamps being related to the amplitude of the focus indication signal, such that with, increasing amplitude of the latter more of the lamps are, …
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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 August 19, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 19, 2003.
- 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.