GB1346673A - Method of data recording using silica-metal oxide record medium - Google Patents

Abstract

1346673 Recording data NATIONAL CASH REGISTER CO 2 Sept 1971 [14 Sept 1970 (2)] 40932/71 Heading C1M Data is recorded using record medium which comprises a sheet like layer comprising silica and the elements lead and copper in the form of an oxide or a reduction product thereof (which product may be the elemental metal or any other reduction product) visible patterns being produced in the medium by reduction of the oxides and the erasure of such patterns by oxidation of the reduction products. The layer may also contain aluminium and boron oxides. In one embodiment the layer is produced by depositing lead and copper on to a silica glass substrate, e.g. "Pyrex" (Registered Trade Mark) and heating in air at 400-700‹ C. to oxidize the metals, migration of substrate material into the leadcopper layer forming the record medium. In a second embodiment a PbO-Cu 2 O glaze is applied to a silica containing substrate and the coated substrate is fired at 1000‹ to 1400‹ C., migration of substrate materials into the glaze layer forming the record medium. Visible patterns may be produced on the medium by heating selected areas thereof to a temperature of 600-900‹ C. and contacting with a reducing agent. Specifically the medium can be heated with a methane or butane-oxygen flame and then contacted with the reducing part of the flames, or the medium can be heated by a laser beam in the presence of an extraneous reducing agent such as ethyl alcohol. Erasure may be achieved by heating to a temperature of at least 200‹ C. or the use of a chemical oxidizing agent such as potassium permanganate, hydrogen peroxide or eerie ammonium sulphate.