CAPACITANCE TOUCHPAD DATA INPUT DEVICE AND KEYBOARD

摘要

A data input device (300) includes multiple keys formed by conductor plates underlying a dielectric layer. Each of the first and second keys (331, 332) has one conductor plate (12, 24) coupled to a corresponding capacitance sensing module (312, 314). The third key (333) has two conductor plates, one (32) coupled to the first capacitance sensing module (312) and the other (34) coupled to the second capacitance sensing module (314). When a user touches a key (331), the user and the conductor plate (12) forms a sensing capacitor (113) having a capacitance greater than that of a reference capacitor (123). A comparison module (130) in the corresponding capacitance sensing module (312) generates a digital bit signal indicating the key (331) being touched. A decoder (301) decodes the digital bit signals of the multiple capacitance sensing modules (331, 332, 333) to generate a digital data signal accordingly.