Piezoelectric element oscillatory wave motor and optical apparatus

Abstract

A piezoelectric element that can decrease the output voltage for detection relative to the input voltage for driving without requiring a step-down circuit between a detection phase electrode and a phase comparator and an oscillatory wave motor including the piezoelectric element are provided. A piezoelectric element includes a piezoelectric material having a first surface and a second surface, a common electrode disposed on the first surface, and a drive phase electrode and a detection phase electrode disposed on the second surface. An absolute value d(1) of a piezoelectric constant of the piezoelectric material in a portion (1) sandwiched between the drive phase electrode and the common electrode and an absolute value d(2) of a piezoelectric constant of the piezoelectric material in a portion (2) sandwiched between the detection phase electrode and the common electrode satisfy d(2)<d(1). An oscillatory wave motor includes this piezoelectric element.

Dependencies are inferred from the claim text.