| 摘要 |
<p>PURPOSE:To detect a contact position of an input medium without requiring a mechanical operation, by detecting a light beam which has been scattered by the input medium which contacts the upper face of a transparent plate, and has been propagated by a total reflection in the transparent plate, by two orthogonal directions. CONSTITUTION:A light source 3 is lighted, and an input medium 5 such as a hand finger, etc. is made to contact an optional position of an input area 11. A light beam which has been scattered by a contact part, and has been propagated repeatedly by a total reflection in a transparent plate 1 consisting of glass, etc. is emitted downward from a pair of optical elements (holograms) 2 which have been provided so as to be opposed, in the vicinity of the right side of the transparent plate 1 and in the vicinity of the rear side, and inputted to a pair of photodetectors (a train of photodetectors) 4 which have been provided so as to be opposed to the optical elements 2. A scattered light from the input medium 5 is scattered in every direction, but the diffraction efficiency of the scattered light for satisfying a Bragg's condition becomes the highest, an output of the photodetector 4 which has received a diffracted light becomes a curve having a peak, and X-Y coordinates of the center of the input medium 5 can be known from an output of a pair of photodetectors 4.</p> |
