Optical focussing-error detection array
CA 1189618 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Compaan, Klaas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
14, ABSTRACT:, Optical focusing-error detection device An optical focusing error-detection device is described which comprises a radiation sensitive detector which comprises four sub-detectors, and an astigmatic lens system arranged between the detector and the objective system whose focusing error is to be detected. If the astigmatic system comprises two cylindrical lenses having mutually perpendicular axes and having different powers which lenses are arranged in a non-collimated beam the, resulting focusing-error signal will be linear around the zero point and will also be symmetrical.
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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 June 25, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 25, 2002.
- 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.