Electrically integrated touch input and output display system

Abstract

A user touch input and output display system which combines elements of a capacitive attenuator type touch switch and a display into a single system. In one embodiment type, one of the electrodes of the display performs double duty as a rear pad, for example a transmitter pad, of a capacitive attenuator type touch switch. The other rear pad necessary for operation of a capacitive attenuator touch switch may either be within the same chamber or envelope as the display electrodes, or may be outside the chamber. The display may for example be a gas discharge display, and the shared electrode does double duty as the display anode and a touch switch transmitter pad. Alternatively, the display may be a liquid crystal display. In embodiments where the other rear pad is within the chamber, to avoid noise interference to the touch switch caused by the gaseous discharge, it is preferable to operate the system in a display mode and in a touch switch mode at different times. During the touch switch mode, the display anode which also serves as the touch switch transmitter pad is supplied with an effectively AC signal. During the display mode, the display anode may be supplied with either a pulsating or a steady DC voltage. In another embodiment type, a liquid crystal display is driven by an AC voltage source having a high series impedance, and a display electrode is capacitively coupled to a touch pad. When a user touches the pad, sufficient signal is shunted to ground to drop the voltage across the display electrode below that necessary to maintain visible energization.

Dependencies are inferred from the claim text.