| 摘要 |
<p>An acoustic transducer for practically efficient acoustic mode conversion is used to generate a high-intensity signal in a touch-sensitive coordinate input device. A device according to the invention comprises acoustic transducers (piezoelectric oscillators) (3a, 4a) for generating a bulk wave (first wave) toward the surface (2) of a substrate (1), acoustic gratings (diffraction gratings) (5a-6b) for conversion between bulk wave and surface acoustic wave (second wave), and means for detecting the disturbance of the second wave on the surface of the substrate. The acoustic gratings (5a-6b) have the following characteristics: (i) grating thickness h=15 to 39 νm, (ii) W/P=0.4 to 0.95, where W is grating size and P is grating pitch, (iii) h2L⊃750 νm2-mm, where L is the coupling length of acoustic grating, (vi) ςh2L⊃3.5x10?6 νm2¿-mm-kg/m3, where ς is grating density.</p> |
