Touch screen device

A touch screen device comprising:

• a touch screen that includes an operation surface on which touch operations are performed, and in which electrostatic capacitances change at regions of the operation surface touched by conductors;
• a pressure sensor unit to output a pressure detection signal corresponding to a pressing value of a pressing force applied to the operation surface;
• and
• a controller to calculate coordinates indicating positions of the touch operations on the operation surface on a basis of the electrostatic capacitances,
• wherein the touch operations include a first touch operation on the operation surface and a second touch operation on the operation surface,
• wherein the controller
• determines touch operation information input by the second touch operation to be valid when a first condition is satisfied, and
• determines the touch operation information input by the second touch operation to be invalid when the first condition is not satisfied,
• wherein the first condition is that the first touch operation is being performed and a pressing value of a pressing force of the first touch operation is within a predetermined reference pressure range having an upper limit and a lower limit, and
• wherein the controller
• previously stores a reverse calculation conversion table used to obtain a pressing value of a pressing force of the first touch operation before the second touch operation is performed, from coordinates of a position of the first touch operation, coordinates of a position of the second touch operation, and a pressing value of a sum of pressing forces of the first touch operation and the second touch operation, and
• uses, as the pressing value of the pressing force of the first touch operation before the second touch operation is performed, the pressing value obtained using the reverse calculation conversion table to determine whether the touch operation information input by the second touch operation is valid.