Three laser optical disk drive system
CA 2071852 A1 · Owner: Ziegler, William Robert Allen · Inventors: Ziegler, William Robert Allen; Goldsmith, Paul
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An erasable optical disk drive system is disclosed which utilizes an electron trapping media (14) coated on the disk surface (10) to store data in the form of light energy and which utilizes three laser beams (50, 52, 54), each having a wavelength range distinct from each other as well as distinct from the wavelength range of the emission produced by the impingement of the read laser onto the electron trapping media. Data is written onto the disk which is contained in a light-tight contamination-free environment using a visible light laser beam. Data is read from the disk and the disk is erased by using a near infrared light laser beam (52). The focus and tracking functions of the disk …
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
- Filed December 12, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 12, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 12, 2012.
- 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.