On-screen input image display system
View Patent ↗A detection resolution is improved in a display device that employs an electrostatic capacity coupling type touch panel provided with a transparent conductive film serving as a detection film. A plurality of electrode terminals ( 102 ) is provided such that at least three electrode terminals ( 102 ) are aligned in each side of a detection transparent conductive film ( 101 ). A touch panel control circuit is provided for selecting one of two to four numbers of electrode terminals from among the plurality of electrode terminals ( 102 ) of the detection transparent conductive film ( 101 ), applying an AC signal provided from a signal source ( 105 ) through a current detection resistor (r) ( 103 ), and then detecting a current that flows through each of the selected electrode terminals.
1. An on-screen input image display system, comprising:
a touch panel for detecting two-dimensional coordinates of a touch position located on a display screen of a display device, the touch panel comprising a plurality of electrode terminals such that at least eight electrode terminals are aligned with one electrode terminal in each of the four corners and four center portions such that there are at least three electrode terminals on each side of the touch panel; and
a touch panel control circuit for selecting two or four electrode terminals from among the plurality of electrode terminals, and then applying an AC signal through a current detection resistor and detecting a current that flows through each of the selected electrode terminals,
wherein coordinate detection is performed in two separate periods so that in a first period of the two separate periods, a touch in one of four regions is detected by selecting terminals at four corners from among the plurality of electrode terminals, and in a second period of the two separate periods, coordinates are detected by controlling electrodes selected in accordance with the region detected in the first period;
wherein in X-directional detection processing, the coordinate detection is performed by selecting one or two electrode terminals in each of two sides vertically facing each other such that the region identified on the basis of coordinate detection results obtained in the first period is included; and
in Y-directional detection processing, the coordinate detection is performed by selecting one or two electrode terminals in each of two sides horizontally facing each other such that the region identified on the basis of the coordinate detection results obtained in the first period is included.
2. An on-screen input image display system according to claim 1 , wherein the X-directional detection processing for detecting a horizontal coordinate and the Y-directional detection processing for detecting a vertical coordinate are repeated to thereby continuously perform the coordinate detection.
3. An on-screen input image display system according to claim 2 , wherein:
in the X-directional detection processing, a touched region is determined by comparing a result of current detection obtained by selecting the electrode terminals in accordance with the region identified on the basis of the coordinate detection results obtained in the first period; and
in the Y-directional detection processing, the touched region is determined by comparing a result of current detection obtained by selecting the electrode terminals in accordance with the region identified on the basis of the coordinate detection results obtained in the first period.
4. An on-screen input image display system according to claim 3 , wherein, in the touch panel, the X-directional detection processing and the Y-directional detection processing are controlled in accordance with sensor areas defined in advance.
5. An on-screen input image display system according to claim 1 , wherein the touch panel is an electrostatic capacity coupling type touch panel employing a detection transparent conductive film arranged on a display screen of the display device.