Abstract: An encoder has a scale having an optical, magnetic or electrostatic displacement detection pattern. An encoder head detects the displacement detection pattern and generates at least two periodic signals that differ in phase, thereby to determine a displacement with respect to the scale. A center-voltage detecting unit detects only the center voltage of each periodic signal. A reference-voltage adjusting unit adjusts the center voltage detected by the center-voltage detecting unit to a predetermined reference voltage.

Abstract: An encoder includes an encoder scale having a predetermined cyclic pattern, and at least one detection unit configured to detect a cyclic displacement according to movement of the encoder scale. The encoder further includes a signal elimination unit configured to subtract, from an output signal of the at least one detection unit, one of an entirety of a DC signal component, which is free from dependency on a relative displacement of the encoder scale, and a signal component that is proportional to the DC signal component.

Abstract: Disclosed herein is an electrostatic drive mirror apparatus including: electrostatic drive mirrors to be variably operated by electrostatic drive; an electrostatic mirror drive section formed on one semiconductor substrate, including at least mirror drive electrodes for driving the electrostatic drive mirrors and signal wirings for applying drive voltage on the mirror drive electrodes; a variable voltage source for supplying voltage from an external source to the electrostatic mirror drive section; drive switches for controlling and driving applied voltages from the variable voltage source to the electrostatic mirror drive section; holding capacitors for retaining the applied voltage to the electrostatic mirror drive section; and a control section for controlling at least the drive switches and the variable voltage source.