| 摘要 |
PURPOSE:To set a low resonance frequency optionally, not to mention a high resonance frequency by an extension part which has specific length and width at the free end of a thin elastic plate, and fitting a weight of specific mass atop of this extension part. CONSTITUTION:A vibration sensor 10 has a vibrator 18 formed by adhering a piezoelectric element 20 to the thin elastic plate 22 cut in a specific shape. The thin elastic plate 22 is supported on cantilever basis so that one end side is a fixed part 24 and the other end side is the free end. The extension part 28 having the specific length and width is provided at the free end side 26, and the weight 30 of the specific mass is fitted atop of the extension part 28 with an adhesive, etc. The resonance frequency is set depending upon the compliance of the extension part 28 and the mass of the weight 30. Consequently, the resonance frequency, i.e. detection frequency is set freely either in a high frequency range or in a low frequency range. |
