| 摘要 |
In a dust removing device including a vibration plate, which includes on its surface an optical effective region B having a substantially right-angled quadrate shape and an outer region A, and a piezoelectric element, when a region positioned in one end portion of the piezoelectric element in a direction along a side O of the piezoelectric element and spanning along the side P over a length b inwards from a line, which is an extension of a side N, N′ of the optical effective region B and which intersects the piezoelectric element, is denoted by an near-end zone &sgr; of the piezoelectric element, an absolute value of piezoelectric constant of the piezoelectric material in a region not including the near-end zone &sgr;, is denoted by d, and an absolute value of the piezoelectric constant in the near-end zone &sgr; is denoted by d0, relation of d>d0 is satisfied. |
