| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement sensor which has a simple structure and is capable of accurately and surely detecting a displacement of a bending amount or a torsion amount independent of a measurement temperature.SOLUTION: A displacement sensor 10 includes a long rectangular elastic body 20. A piezoelectric element 30 is attached to a first principal surface of the elastic body 20. The piezoelectric element 30 includes a long rectangular piezoelectric sheet 300 and electrodes 301 and 302 formed on both principal surfaces of the piezoelectric sheet 300. The piezoelectric sheet 300 is made of poly-L-lactic acid and has been subjected to uniaxial drawing. The piezoelectric element 30 is attached so that a uniaxial drawing direction of the piezoelectric sheet 300 forms 45° relative to a lengthwise direction of the elastic body 20. When the elastic body 20 is bent along the lengthwise direction, the piezoelectric sheet 300 stretches along the lengthwise direction, thereby the piezoelectric element 30 generates a voltage of a predetermined level. |
