Abstract: A capacitive sensor electrode for controlling activation and deactivation of a PTC conductive ink heater can be deposited as part of the same layer of conductive ink used to form the open heater circuit pattern for the heater. A layer of conductive ink is deposited on an insulating substrate, with a first portion of the layer forming an open heater circuit pattern and a second portion of the layer forming a capacitive sensor electrode spaced from and electrically isolated from the first portion of the layer. A layer of positive temperature coefficient (PTC) conductive ink is deposited so as to bridge gaps between in the open heater circuit pattern while leaving the capacitive sensor electrode spaced from and electrically isolated from the layer of PTC conductive ink on the first portion of the layer of conductive ink.

Abstract: A capacitive sensor electrode for controlling activation and deactivation of a PTC conductive ink heater can be deposited as part of the same layer of conductive ink used to form the open heater circuit pattern for the heater. A layer of conductive ink is deposited on an insulating substrate, with a first portion of the layer forming an open heater circuit pattern and a second portion of the layer forming a capacitive sensor electrode spaced from and electrically isolated from the first portion of the layer. A layer of positive temperature coefficient (PTC) conductive ink is deposited so as to bridge gaps between in the open heater circuit pattern while leaving the capacitive sensor electrode spaced from and electrically isolated from the layer of PTC conductive ink on the first portion of the layer of conductive ink.