| 摘要 |
<p>PURPOSE:To improve the precision of coordinate detection based on measurement of the oscillation transmission time by controlling the temperature of an oscillation-proof material or an oscillation transmission plate so that a desired oscillation transmission characteristic including the oscillation reflection factor, the oscillation attenuation factor, etc., is attained. CONSTITUTION:A hot wire 701 is controlled by a power controller 702. The controller 702 controls the hot wire 701 by an open loop of driving at intervals of a prescribed time or by a close loop using a thermostat, a thermistor, or the like so that the temperature of an oscillation-proof material 7 or an oscillation transmission plate 8 is approximately fixed. Since the oscillation-proof material 7 is controlled to such temperature that the highest oscillation attenuation factor and the lowest oscillation reflection factor are obtained with respect to its material, the reflected wave generated in the peripheral part of the oscillation transmission plate is effectively attenuated, and the reflected wave is prevented from being inputted as the noise to an oscillation sensor 6 because reflection is suppressed.</p> |
