| 摘要 |
<p>PURPOSE:To contrive the improvement of the coordinate detection accuracy by arranging a vibration sensor on a vibration transmitting plate with a prescribed distance larger than a reflection interference distance of vibration apart from the boundary face where the specific acoustic impedance of a vibration transmitting plate ridge is changed so as to prevent the distortion in the vibration detection waveform at the boundary face of the ridge of the vibration transmitting plate caused by a reflection wave. CONSTITUTION:When the distance between the vibration sensor 6 and the reflection boundary face 82 is parted only by a reflection interference distance L as shown in figure (A), the effective transmission range 84 is linear, but in parting the vibration sensor 6 from the reflection boundary face 82 over the reflection interference range L as shown in figures (B)-(D), the effective transmission range 84 of the direct wave is being spread sectorially. That is, the vibration sensor 6 is parted sufficiently from the reflection interference range as shown in the figure (D). Thus, the distortion due to the combination of the reflected wave from the boundary face 82 where the specific acoustic impedance of the vibration delivery plate 8 changes onto the detected waveform is avoided and the coordinate detection accuracy based on the vibration detection is improved remarkably.</p> |
