| 摘要 |
<p>PURPOSE:To shorten the time of coordinate position detection and to reduce cost by measuring the crest value of a pulse signal, which is instantaneously generated on the secondary-side of a pulse transformer at the time of the rise of a waveform, and detecting a touch position based on the crest value. CONSTITUTION:One end of a pulse signal generator 13 is connected to a power source-side and the other end to one coil on the primary-side of the pulse transformer 14. One end of the resistance film 12 of a touch panel 11 is connected to the coil of the pulse transformer 14 and the other end, and the secondary-side of the pulse transformer 14 is connected to a detection circuit 15. The rise time of the pulse signals b and b' of the current waveform flowing on the primary-side of the pulse transformer 14 in accordance with resistance decided in accordance with the position where an impedance 16 touches the touch panel 11 is decided. Then, a current change per unit time, which is required for the rise time, is generated as the crest value of the voltage waveform showing a voltage change amount on the secondary-side of the pulse transformer 14 and a coordinate position is detected based on the crest value.</p> |
