| 摘要 |
<p>PURPOSE:To obtain a pen input device with a low power consumption and high performance by turning on the power source of a coordinate detection pulse amplification means when an input pen is nearby a liquid crystal panel and turning off the power source when the input pen is put away from the liquid crystal panel. CONSTITUTION:The amplifier common power source 111 is turned on by the switch-on of the pen switch provided to the input pen 4, and the common power source 111 is turned off when the leaving of the input pen 4 from nearby the liquid crystal panel 1 is detected from a PR signal 106 which is turned on when the input pen 4 is positioned nearby the liquid crystal panel 1 and turned off when the input pen is put away from the liquid crystal panel 1. The amplifier common power source 111 is therefore in OFF state until the pen switch is turned on after pen input is started, and then turned off when it is judged that the RP signal 106 is turned off. Consequently, the current consumption UP of a coordinate detection pulse amplifier 6 and a PR signal amplifier 7 is suppressed to make the power consumption of the device low.</p> |
