Patent ID: 7808490
Filing Date: 2010-10-05
Classification: G06F

Abstract:
1. A device for determining a touch position on a sensing area of a capacitive touch panel, comprising: a signal providing unit alternatively providing an alternating current (AC) scan signal having a frequency and a current value to each of four corners of the capacitive touch panel, respectively; a frequency switching unit rapidly switching the frequency of the AC scan signal associated with each of the four corners among a group of specific frequencies; a voltage driving and current detecting unit driving the capacitive touch panel by alternatively using the AC scan signal associated with each of the four corners, respectively, and detecting the current value of the AC scan signal of each of the group of specific frequencies associated with each of the four corners of the capacitive touch panel, respectively; a valid frequency selecting unit receiving the current value of the AC scan signal of each of the group of specific frequencies associated with each of the four corners of the capacitive touch panel, respectively, and selecting a group of selected frequencies according to a noise filtering procedure from the group of specific frequencies associated with each of the four corners of the capacitive touch panel based on the current value of each of the group of specific frequencies, respectively; a valid current value selecting unit obtaining a final current value by calculating the current value of the AC scan signal of each of the group of selected frequencies associated with each of the four corners of the capacitive touch panel, respectively; and a position coordinate calculation unit calculating a coordinate value of the touch position on the capacitive touch panel based on the final current value associated with each of the four corners of the capacitive touch panel, respectively.