CAPACITIVE TOUCH SENSOR, DISPLAY OR PANEL

摘要

There is disclosed a capacitive touch pad or device (10) which includes a substrate (12) and a plurality of capacitive pads (18) at an inner surface (16) of the substrate (12). Each pad (18) is provided with a local oscillator (22), the oscillation frequency of which varies with the capacitance of the capacitive pad (18). A micro controller (26) is operable to sense the oscillation frequency of the oscillators (22). In order to be usable in humid and wet environments, the microcontroller (26)operates on the basis of a time averaged signal from each of the oscillators (22) and compares this to a threshold, which threshold in the preferred embodiment is variable, for instance by time-averaging. The oscillators (22) is preferably close to the capacitive pads (18) in order to allow the use of a thicker substrate (12) and in the preferred embodiment a substrate which is waterproof. These arrangements provide a capacitive touch sensor device which can be used in humid or wet conditions.