Touch panel, method for detecting touch input position, electro-optic device, and electronic device

An electro-optic device comprising:

• an image display device on which a plurality of pixels are arrayed in rows;
• and
• a touch panel arranged on an image display side of the image display device, wherein
• the touch panel includes:
• a touch panel substrate having an input surface;
• a cover film arranged separately from the input surface, and facing to the input surface;
• spacers extending upright from the touch panel substrate toward the cover film;
• a transmitter causing surface acoustic waves to be propagated on the input surface;
• a receiver measuring the surface acoustic waves propagated on the input surface;
• a memory storing, as reference values, measurement values of the surface acoustic waves when the cover film is not being pressed;
• and
• a determination section detecting, as touch input positions, positions at which a difference between the measurement values of the surface acoustic waves when the touch panel is being used and the reference values is significant.