Patent ID: 9477357
Filing Date: 2016-10-25
CPC Classification: G06F

Claim Text:
1. A touch input system comprising: a sensor panel comprising a plurality of first channels and a plurality of second channels crossing each other; a stylus comprising one or a plurality of primary coils connected in series to each other, a resonance capacitor connected in parallel to the primary coil, and a conductive tip connected to the primary coil; a ground connected to the stylus; an antenna loop formed outside an edge of the sensor panel; and a touch controller directly connected to the plurality of first channels, the plurality of second channels, and the antenna loop, wherein a sensing capacitor is formed at a contact area between the conductive tip and the sensor panel, wherein a drive signal is applied to each channel of the sensor panel from a drive signal generator of the touch controller, and a resonance circuit including the primary coil and the resonance capacitor of the stylus electromagnetically resonates with a same resonant frequency of the applied drive signal input through the sensing capacitor, and wherein the resonance frequency satisfies the condition: f=1/[2π*(L wherein the touch controller includes an amplifier for amplifying a voltage difference between two ends of the antenna loop, a filter unit connected to the amplifier to remove noise, a converter connected to the filter unit to convert an analog signal into a digital signal, a signal processor connected to the converter to collect digital signal to extract coordinates, and the drive signal generator.