Touch panel apparatus and method for detecting distance between touch input points on touch panel

A touch panel apparatus comprising,

• a touch panel composed of two resistance films, each having a pair of electrode terminals at edge side portions opposing each other, the two resistance films closely opposing each other to be capable of being in contact with each other so that the pair of electrode terminals are vertically perpendicular to each other;
• a first voltage detector adapted to, with a power-supply voltage being applied between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detect a voltage of any one of the pair of electrode terminals of the other of the resistance films;
• a second voltage detector adapted to, with a power-supply voltage being applied, through a resistance, between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detect a voltage of any one of the pair of electrode terminals of the other of the resistance films;
• a two-point touch determining circuit designed to determine whether or not two points are touched on the touch panel based upon a ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector;
• a pressing force detector adapted to detect a pressing force of a touch input when the two-point touch determining circuit determines that the two points are touched;
• and
• a two-point distance detector adapted to detect a distance between the two points based upon the ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector, and the pressing force measured by the pressing force detector, when the two-point touch determining circuit determines that the two points are touched.

A method for detecting a distance between touch input points of a touch panel, the method comprising:

• as a first voltage detecting step, with a power-supply voltage being applied between a pair of the electrode terminals arranged at edge side portions opposing each other in each of two resistance films in a touch panel, the two resistance films closely opposing each other to be capable of being in contact with each other so that the pair of electrode terminals are vertically perpendicular to each other, and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detecting a voltage of any one of the pair of electrode terminals of the other of the resistance films;
• as a second voltage detecting step, with a power-supply voltage being applied, through a resistance, between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detecting a voltage of any one of the pair of electrode terminals of the other of the resistance films;
• determining whether or not two points are touched on the touch panel based upon a ratio of the voltage detected by the first voltage detecting step and the voltage detected by the second voltage detecting step;
• detecting a pressing force of a touch input when the two-point touch determining step determines that the two points are touched;
• and
• detecting a distance between the two points based upon the ratio of the voltage detected by the first voltage detecting step and the voltage detected by the second voltage detecting step, and the pressing force measured by the pressing force detecting step, when the two-point touch determining step determines that the two points are touched.