Display for small device, e.g. smart card, has two neighboring layers, one of thermally rewritable material and other with individually switched foil type heating elements

摘要

The display device (1) has a layer containing several foil type heating elements (3) deposited on top of a card substrate (5). Another layer (2) of thermally rewritable material is made on top so that the individually switchable heating elements (3) and corresponding lead wires are embedded in the rewritable material. This in turn is covered by a protection layer (6). The heating elements form a 7-segment display or a point matrix to display different signs and symbols, letters, digits, etc.