| 摘要 |
<p>PURPOSE:To reduce a reflected wave in an end part and to reduce noise at the time of detecting vibration by arranging plural vibration proofing members in a laminated form and setting the acoustic impedance of a layer near a vibration transmission board to be smaller than the acoustic impedance of a layer far from it. CONSTITUTION:The vibration proofing member 7 is provided in the peripheral part of the vibration transmission board 8. Plural vibration proofing members are arranged in the laminated form, and the acoustic impedance of the layer near the vibration transmission board 8 is set to be smaller than the acoustic impedance of the layer far from the vibration transmission board 8 in the vibration proofing member 7. The widths of respective layers of the vibration proofing member 7 become wider as they approach the vibration transmission board 8 and project to the center side of the vibration transmission board 8. furthermore, the vibration proofing members 7 are stuck by bonding or adhension.</p> |
