Patent ID: 8890851

Claim:
An optical position detection device comprising: a light source section adapted to radially emit detection light along an imaginary plane defined by a first direction and a second direction perpendicular to each other; first and second light receiving elements that are disposed at a position overlapping a radiation center of the detection light when viewed from a third direction perpendicular to the imaginary plane, and that are adapted to receive the detection light reflected by a target object, the first and second light receiving elements being located to overlap with each other in the third direction; third and fourth light receiving elements that are adapted to receive the detection light reflected by the target object, the first and second light receiving elements being located at a position, which is on a perpendicular bisector with respect to a connection line connecting between the third and fourth light receiving elements, with a gap from the connection line in the second direction, and a position detection section adapted to detect a position of the target object based on a light reception intensity in each of the first through fourth light receiving elements, wherein the first through fourth light receiving elements have first through fourth normal directions with respect to first through fourth light receiving surfaces, respectively, the first normal direction is different from the second normal direction, a first angle between the first normal direction and the perpendicular bisector is equal to or larger than a second angle between the third normal direction and the perpendicular bisector, and a third angle between the second normal direction and the perpendicular bisector is equal to or larger than a fourth angle between the fourth normal direction and the perpendicular bisector.