Patent ID: 8773368

Claim:
An information input device comprising: an input panel including an illumination light source, a plurality of first light-receiving elements and one or more second light-receiving elements, the illumination light source emitting detection light for detecting an external proximity object, the plurality of first light-receiving elements receiving detection light emitted from the illumination light source and then reflected from the external proximity object, the second light-receiving elements monitoring the intensity of the detection light; a correction section performing adaptive sensitivity correction on light-receiving signals obtained by the first light-receiving elements through use of an intensity monitor signal of detection light obtained by the second light-receiving element, so that the light-receiving signals output from the correction section maintain a substantially uniform intensity; and an image processing section obtaining object information about one or more of the position, shape and size of the external proximity object on the basis of a picked-up image obtained from the light-receiving signals output from the correction section, wherein the second light-receiving element has a light-shielding region for preventing light from directly illuminating the second light-receiving element, and the adaptive sensitivity correction includes generating a difference signal from the light receiving signal, and generating a sensitivity correction signal from the difference signal with a sensitivity correction table in addition to the intensity monitor signal.