Method for scanning projective capacitive touch panel

Abstract

The present invention relates to a method for scanning a projective capacitive touch panel. The method includes the following steps: scanning the mutual capacitance that are divided into at least two groups by applying different frequency excitation signals to different mutual capacitance groups, wherein a frequency of a excitation signal applied to a mutual capacitance group with greater RC constant is lower than that of a excitation signal applied to a mutual capacitance group with smaller RC constant; obtaining a first current voltage of each mutual capacitance; comparing the first current voltage with a first reference voltage to obtain candidate mutual capacitance whose first current voltage exceed the first reference voltage by a first threshold value; scanning the candidate mutual capacitance by applying a low frequency excitation signal; obtaining a second current voltage of each candidate mutual capacitance; comparing the second current voltage of each candidate mutual capacitance with a corresponding second reference voltage to obtain touched mutual capacitance whose second current voltage exceed the corresponding second reference voltage by a second threshold value.