Keyboard based in polymer, copolymer or composites with piezo- and/or pyroelectric properties and respective use

摘要

The invention refers to a new keyboard based in a polymeric, copolymeric or composite film (11) with piezo- and pyroelectric properties capable of receiving a tactile signal and giving a respond in the form of an electrical signal. The system described in this invention includes one or more keys (10), being each one of them made by a piezoelectric film (11) with electric conductive contacts, transparent or not, above and below the piezoelectric film and with the inferior layer of grounded electrodes (13). The present invention allows the use of just one piezoelectric film (11) without external power supply, the use of electrode connections which form the keys (10) that converge in one side of the keyboard and are available in the spots (12) to make the connection to the active filter circuits instead of amplifiers in the electronic readout, as well as the possibility of introduction of new functionalities in these keyboards identical to the ones of tactile sensors, upon distinction between a pyroelectric and a piezoelectric signal from a particular key, differing the signals generated by pressure variation or by temperature variation.