Patent ID: 8058883

Claim:
A method for detecting capacitance, the method comprising: allowing an oscillator to output a plurality of time division oscillation frequencies according to the capacitance detected by a capacitance detection plate; counting the plurality of time division oscillation frequencies during a predetermined time period; and offsetting increasing and decreasing of the oscillation frequencies due to noise such that a count value becomes uniform over the predetermined time period, wherein when the plurality of time division oscillation frequencies fo 1 , fo 2 , . . . , fo(nâˆ’1) and fon satisfies a relationship of fo 1 <fo 2 < . . . <fo(nâˆ’1)<fon and a period for generating the frequency fo 1 is tp 1 , a period for generating the frequency fo 2 is tp 2 , . . . , and a period for generating the frequency fon is tpn, the oscillator oscillates such that tp 1 >tp 2 > . . . tp(nâˆ’1)>tpn is set.