If minimal
capacitance change of
fingerprint peak and
fingerprint valley in a
fingerprint needs to be sensed by utilizing
capacitance sensing, a high-sensitivity sensing circuit must be designed. However, higher the sensitivity of the sensing circuit is, larger the
noise accompanied therewith is, and especially for the press-type
capacitance sensing array, a capacitance sensing unit and the accompanied
noise change with the difference at different lines and rows. The fingerprint sensor can eliminate possible stray capacitance in the circuit
layout, and furthermore, is configured with an offset
elimination circuit; the offset
elimination circuit has two different capacitors so as to carry out optimum
processing on the capacitance sensing
noise; and then, fingerprint peak and fingerprint valley signals passing through the offset
elimination circuit can be connected to an
amplifier to improve individual
signal intensity. Therefore, through the two capacitors of the offset elimination circuit, the signals of each sensing
electrode is allowed to be optimum.