초록 ▼

A dynamic biasing capacitance is formed between a transmitting electrode and a receiving electrode of a capacitive touch-pad device to couple a portion of the scan voltage signal into the sense node of a voltage comparator circuit, coupled to the receiving electrode, to offset the comparator circuit

A dynamic biasing capacitance is formed between a transmitting electrode and a receiving electrode of a capacitive touch-pad device to couple a portion of the scan voltage signal into the sense node of a voltage comparator circuit, coupled to the receiving electrode, to offset the comparator circuit threshold voltage. The dynamic biasing capacitance may be formed by overlapping portions of the electrodes, with a dielectric layer positioned therebetween, or by the parasitic capacitance between aligned end surfaces of the two electrodes, with the magnitude of the dynamic biasing capacitance being adjusted by variation of interelectrode geometries.

대표청구항 ▼

A capacitive touch pad device comprising: a substrate of dielectric material having first and second opposed surfaces; a single conductive touch electrode responsive to human communication fabricated upon said first surface over a preselected continuous area; a pair of spatially separated electrodes

A capacitive touch pad device comprising: a substrate of dielectric material having first and second opposed surfaces; a single conductive touch electrode responsive to human communication fabricated upon said first surface over a preselected continuous area; a pair of spatially separated electrodes fabricated upon said second surface substantially within an area overlying and bounded by the area of said touch electrode; at least one of said pair of electrodes having at least one extension therefrom extending parallel to and spaced from at least one surface of the remaining one of said pair of electrodes; and dielectric material filling the volume defined between said electrode extension and the confronting portion of said remaining electrode to provide a first electrical capacitance therebetween of essentially constant value; the dielectric material of said substrate separating said conductive touch electrode and each of said spatially separated electrodes providing second and third electrical capacitances respectively therebetween of essentially constant value.