Patent ID: 8314722

Claim:
Laminar keyboard based on a material with piezo- and/or pyroelectric proprieties, comprising: a film consisting of a polymeric, copolymeric or composite material with piezo- and/or pyroelectric proprieties; at least one key formed by one conductive electrode and by the film with piezo- and/or pyroelectric proprieties, which thus induces a mechanical and/or thermal signal; a grounded electrode placed underneath the piezoelectric film; connections between the keys and the readout system of the keys by means of the contact points; a band-pass filter that separates the piezoelectric and the pyroelectric effects through the regulation of its central frequency; a multiplexer which establishes the electric connection between each contact point and the bandpass filter a rectifier which eliminates the negative component from the output signal on the band-pass filter; and a low-pass filter, that filters the signal from the rectifier or a digital circuit of rebound elimination from the signal provided by the rectifier in order to obtain a single pulse at the output for the pressure applied in each key.