Coordinate input device

TL;DR: In this article, the authors proposed a scheme to increase the kinds of switching signals without increasing the number of signal lines between a coordinate indicator and a device main body (device control part) and without generating a coordinate detection error and to allow them to operate in the various kinds of coordinate indicators.

Abstract: PURPOSE:To increase the kinds of switching signals without increasing the number of signal lines between a coordinate indicator and a device main body (device control part) and without generating a coordinate detection error and to allow them to be operated in the various kinds of coordinate indicators. CONSTITUTION:A phase switching means 1b changing the AC signal current phase from the device main body 2 (device control part 22) to a coordinate direction exciting coil 1a by operating a switch SW is provided on a coordinate indicator 1, and phase difference detection means 22m to 22o detecting the difference between the current phase of the AC signal flowing through the coil and the phase difference of the AC signal to be supplied from the device main body to the coil are provided on the device main body 2. The detected phase difference is used as the type of a switching signal. The current phase of the AC signal flowing through a coil is used to perform coordinate detection without generating error by taking the phase difference with the phase of the coordinate detecting AC signal as a reference phase when the indicated coordinate of the coordinate indicator is detected.