| 摘要 |
A displacement sensor (10) has a long elastic member (20) having a rectangular shape. A piezoelectric element (30) is attached to a first main face of the elastic member (20). The piezoelectric element (30) has a long rectangular-shaped piezoelectric sheet (300) and electrodes (301 and 302) formed on both main faces of the piezoelectric sheet (300). The piezoelectric sheet (300) is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element (30) is attached so that the uniaxial-stretching direction of the piezoelectric sheet (30) forms 45° from a long-side direction of the elastic member (20). When the elastic member (20) is bent along the long-side direction, the piezoelectric sheet (300) is stretched along the long-side direction, and the piezoelectric element (30) generates voltage of predetermined level. |
