Security writing
CA 1115419 A · Owner: The Wiggins Teape Group Limited · Inventors: Schwartz, Gerhardt T.; Prior, Allan S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A stylus having an electrically-conductive writing tip is used to write on an electrically-sensitive paper for example a metallized paper in which the metallization is eroded by the current passed by the stulus. The stylus is energised by a coded train of electrical pulses whereby the coding is reproduced in the writing which can thus be verified as genuine. The material to be written on for example an airline ticket whose fraudulent alteration is to be exposed, may be supported on a stand having a conductive resilient arm bearing on the electrically sensitive surface to provide a return path for the stylus current. The principle can be applied with coded optical pulses directed onto an …
Read the whole patent
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 December 29, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 29, 1998.
- 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.