Keyboard based in polymer, copolymer or composites with piezo- and/or pyroelectric properties and respective use
First Claim
1. 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 filtera 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.
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Accused Products
Abstract
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.
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Citations
13 Claims
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1. Laminar keyboard based on a material with piezo- and/or pyroelectric proprieties, comprising:
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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 filtera 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. Laminar keyboard based on a material with piezo- and/or pyroelectric proprieties, comprising:
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a film constituted by 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 a band-pass filter; at least a band-pass filter that separates the piezoelectric and the pyroelectric effects by means of the regulation of its central frequency; 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.
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Specification