Patent ID: 6963331
Filing Date: 2005-11-08
Classification: G06F

Abstract:
1. An apparatus for outputting position information corresponding to light having a cyclically varying intensity, said apparatus comprising: a detection device that receives the light, said detection device comprising a plurality of photoelectric conversion elements, arranged in a predetermined physical array; difference signal generating means for generating, for each photoelectric conversion element, a difference signal corresponding to a difference between an output of the photoelectric conversion element when the light cycle is at a first point and an output of the photoelectric conversion element when the light cycle is at a second point, the first point being at a higher intensity than the second point; threshold setting means for setting a threshold value on the basis of a level of said difference signal obtained from each photoelectric conversion element; selection means for selecting effective photoelectric conversion elements by comparing said threshold value with the difference signal generated by said difference signal generating means; and output means for outputting the difference signals corresponding to the selected effective photoelectric conversion elements.