Reference is made to Fig. 5 which is a schematic view of a coordinate setting of the touch panel. In this example, a liquid crystal display 2 with 240*320 pixels and a touch panel 3 with 280*360 pixels are exemplified to further demonstrate the present invention. The touch panel 3 is installed on the liquid crystal display 2. A primary touch area 31 is defined as an overlapped portion of the touch panel 3 and the liquid crystal display 2, and a secondary touch area 32 is defined as a non-overlapped portion of the touch panel and the liquid crystal display. A first touch area 321, a second touch area 322, a third touch area 323, and a fourth touch area 324 are set on upper side, lower side, left side, and right side of the secondary touch area 32, respectively, and each of the four touch areas (321, 322, 323, and 324) has a 20-pixel width.Furthermore, four corner coordinates of the secondary touch area 32 are set as (-20, -20), (260, -20), (-20, 340), and (260, 340), respectively, and four corner coordinates of the primary touch area 31 are set as (0, 0), (240, 0), (0, 320), and (240, 320), respectively.