| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To sufficiently highly precisely and stably detect coordinates. <P>SOLUTION: An optical unit 13 is provided with a beam splitter 442 which branches intensity modulation rays of light emitted from a semiconductor laser 442, and an optical sensor 444 which receives one of the rays of light branched by the beam splitter 442, and outputs an electric signal showing the change of the intensity of the rays of light, a diffusion optical system 443 which diffuses the other of those branched rays of light into sheet-shaped lights extended like a fan, and emits the rays of light along a coordinate input face 41, an optical sensor 445 which receives reflected rays of light to one of those branched rays of light, and outputs the electric signal expressing the change of the intensity of the rays of light and a phase comparing part 463 which calculates a phase difference between the intensity change of the emitted rays of light and the intensity change of the reflected rays of light by using the electric signal outputted from the optical sensors 444 and 445. Optical path length from the diffusion optical system 443 to the optical sensor 445 is calculated by subtracting the optical path length from the beam splitter 442 to the optical sensor 444 from the optical path length from the beam splitter 442 to the diffusion optical system 443. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
