OPTICAL TOUCH PANEL AND INPUT COORDINATE DETECTING METHOD USING THE PANEL

PURPOSE:To sharply reduce the number of parts and production cost and to sharply improve detection accuracy. CONSTITUTION:Plural light emitting elements 13 are arrayed along two adjacent sides 12a, 12b of a display screen 12. Optical guide members 14 are arranged along the other two sides 12c, 12d. A PSD 15 is arranged on an intersecting position between the two sides 12c, 12d of the screen 12. Light from each element 13 is reflected by the members 14 and made incident upon the PSD 15 while leaving the positional relation of incident light and the PSD 15 outputs a signal indicating the centroid position of light. Since a detection circuit 17 can detects also input coordinates located between plural elements 13, the accuracy of coordinate detection can be sharply improved. Since light can be received by a light receiving element arranged only on one corner part of the screen 12, the number of light receiving element can be sharply reduced.