Programmed matrix device.

摘要

A matrix device has a permanently stored code or bit pattern comprising an electrically insulating substrate (2) having a major face carrying successively layered electrically conductive film tracks (1, 7) in non-parallel directions that traverse one another at a multiplicity of locations and are separated by a film of dielectric material (3) selected locations have pathways between the tracks of successive layers to define the code or bit pattern. At these locations the pathways are defined by programmed laser formed apertures (5) in the dielectric material (3) that access one or more film tracks (1) of a layer nearer the substrate (2). Film track material (7) of a layer further from the substrate (2) passes through the apertures (5) to make electrical contact with the accessed film tracks (1). The electrically conductive film tracks (1, 7) and the film (3) jof dielectric material are preferably thick film materials and are produced by screen printing. The conductive film tracks (1, 7) may comprise an electrically conductive material fired onto the said substrate, and the film (3) of dielectric material may comprise a glass or a glass-ceramic, also fired onto the said substrate which is a ceramic material. A method of producing the device is also claimed.