A contactless inkjet printed passive touch sensor

A new planar contactless passive all-inkjet printed touch sensor realized by low cost printing technology on a PET substrate is discussed. The device exploits a capacitive readout strategy while the contactless operation is based on the LC resonance method which converts changes of C into the frequency domain. Advantages of the proposed solution reside both in the technological process and contactless readout. Main outcomes of the low cost inkjet technology adopted is the rapid prototyping of really cheap disposable sensors. The passive and contactless readout strategy enables the use of the touch sensor in applications where the device cannot coexist with power sources and conditioning/reading circuit such as uses in hazardous environments.