Displacement amount detection apparatus, displacement amount detection method, and manipulation information output apparatus

A displacement amount detection method of detecting a displacement amount of a movable member using a displacement apparatus comprising:

• a first resonant circuit that includes a first coil mounted to the movable member;
• a second resonant circuit that includes a second coil that generates a magnetic field upon supply of an electric current and is configured to, in a case where the first resonant circuit is mounted opposite the second resonant circuit, output a first signal of a voltage level depending on a relative position of the second coil with respect to a position of the first coil, wherein the second coil faces the first coil in the case where the first resonant circuit is mounted opposite the second resonant circuit;
• a third circuit that does not include a coil and is configured to output a second signal defining a maximum value for the voltage level output from the second resonant circuit;
• and
• a fourth circuit that includes a resistor coupled in parallel to a third coil and is configured to output a third signal defining a minimum value for the voltage level output from the second resonant circuit,
• the method comprising:
• acquiring the second signal output from the third circuit when the electric current is supplied to the third circuit;
• acquiring the third signal output from the fourth circuit when the electric current is supplied to the fourth circuit;
• correcting the first signal based on the second signal and the third signal;
• and
• calculating the displacement amount based on the corrected first signal.