Optical unit for detecting object and coordinate input apparatus using the same

摘要

An object detecting optical unit (1;30) for detecting a direction or a position of an object (33) placed on a detecting plane surface (31) is disclosed. The optical unit detects existence or non existence of a retroreflective light reflected by a retroreflective member (32). The optical unit includes a light projection device which is formed by a plurality of light sources (2) and a plurality of lenses which correspond to the light sources, the plurality of light sources and the plurality of lenses being arranged in such a manner as to form a fan shaped projection pattern parallel to the detecting plane surface, the projection pattern being as if projected from a virtual one point light source (13). The optical unit also includes a light receiving device which has a slit or a lens (4) and a linear photoreceptive group (5), the slit or lens and the linear photoreceptive group being arranged in such a manner as to form a light receiving pattern with a view field corresponding to the fan shaped projection pattern formed by the light projection device. A position coordinate input apparatus using the above optical unit is also disclosed. <IMAGE>