Patent ID: 8698774
Filing Date: 2014-04-15
Classification: G06F

Abstract:
1. The on-screen input image display system comprising a touch sensor for detecting coordinates of a touch position on a display screen of a display device, the touch sensor being disposed on the display screen of the display device and comprising a plurality of X coordinate electrodes and a plurality of Y coordinate electrodes arranged so as to cross the plurality of X coordinate electrodes via an insulator layer, both for detecting a change in capacitance due to pressing, the on-screen input image display system comprising: wherein the main control circuit judges occurrence of a user's touch and coordinates of the occurrence from the touch coordinate data, and supplies a display signal corresponding to the judged coordinates to the display device via the display control circuit, wherein the touch panel control circuit detects, in a first period, an X coordinate electrode and a Y coordinate electrode, in which capacitance changes, and when each of a number of the X coordinate electrodes and a number of the Y coordinate electrodes detected in the first period is two or larger, the touch panel control circuit performs, in a second period, a detecting operation and a true-false determining operation for determining a combination of the detected X coordinate electrode and Y coordinate electrode for which capacitance has been increased by comparing digital data obtained in the first detection period and digital data obtained in the second detection period, and outputs the coordinates of the touch position based on a result of the determining operation; and when one of the number of the X coordinate electrodes and the number of the Y coordinate electrodes detected in the first period is one, the coordinate detection in the first period is continuously performed without performing the determining operation in the second period, wherein a detecting method of the second period is different than a detecting method of the first period, wherein the touch panel control circuit is configured to detect every signal of all of the X coordinate electrodes and all of the Y coordinate electrodes in the first period and to detect only ones of the Y coordinate electrodes determined to be a target of the true or false determination among a plurality of the Y coordinate electrodes in the second period, wherein the touch panel control circuit is further configured to connect others of the Y coordinate electrodes which are not necessary to make the true or false determination to ground during the second period, and wherein the touch panel control circuit is further configured to detect, in the second period, only the X coordinate electrodes among the plurality of X coordinate electrodes which are determined to be necessary to make the true or false determination, while connecting the other X coordinate electrodes of the plurality of X coordinate electrodes to ground.