| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a displacement sensor using a surface acoustic wave, which has high resolution as well as reliability.SOLUTION: The displacement sensor includes: a scale which is made of a piezoelectric material and has a surface acoustic wave propagation surface; at least one excitation electrode formed on the surface acoustic wave propagation surface; a plurality of position electrodes which are formed on the surface acoustic wave propagation surface and are arranged at pitchλ/2 (λis a wavelength of a surface acoustic wave excited by the excitation electrode) along a propagation direction of the surface acoustic wave; a detector which has a detection surface arranged so as to face the surface acoustic wave propagation surface; a pair of first detection electrodes which are formed on the detection surface and are arranged at pitchλ/2; and a pair of second detection electrodes which are formed on the detection surface and are arranged at pitchλ/2 in positions of which the phases are shifted from those of the first detection electrodes by 90°.</p> |
