| 摘要 |
A push-in amount detection sensor (20) includes a piezoelectric film (201), an electrode-formed protective film (202,203), and an adhesive layer (204). The electrode-formed protective film (202,203) adheres to the piezoelectric film (201) with the adhesive layer (204,205) interposed therebetween such that an electrode (222,232) is located on the side of the piezoelectric film (201). Relative permittivity µ a of the adhesive layer (204,205) is higher than relative permittivity µ p of the piezoelectric film (201). Preferably an electrostatic capacitance per unit area of the adhesive layer (204,205) is higher than an electrostatic capacitance per unit area of the piezoelectric film (201), more preferably the electrostatic capacitance per unit area of the adhesive layer (204,205) is substantially double the electrostatic capacitance per unit area of the piezoelectric film (201). The thickness of the adhesive layer (204,205) is set within a predetermined thickness range. |
