Patent ID: 8629989

Claim:
A coordinate input apparatus comprising: a reflection unit formed in a peripheral portion of a coordinate input effective region, and adapted to retroreflect incident light; a light projection unit adapted to project light toward the coordinate input effective region; and a light receiving unit formed at a corner of the coordinate input effective region, coordinate values of a pointed position being calculated based on a light amount distribution obtained by said light receiving unit, wherein said light receiving unit comprises at least: a light receiving element; a light receiving lens; an adjusting unit adapted to adjust a positional relationship between said light receiving element and said light receiving lens; and a light transmissive plate arranged between said light receiving element and said light receiving lens as well as arranged on an optical path of said light receiving element and said light receiving lens, and adapted to define a focal length of said light receiving lens, and said light transmissive plate is arranged on the optical path of said light receiving element and said light receiving lens in a state in which an optical axis between said light receiving element and said light receiving lens is adjusted by said adjusting unit with said light transmissive plate being removed; and said focal length of the light receiving lens is defined by setting the light transmittance of the light transmissive plate.