Patent ID: 8564782

Claim:
A position detection method of detecting a position of a detection target on a supporting member that moves in a predetermined direction, the position detection method comprising: emitting a detection light onto the supporting member with a light-emitting unit; receiving a reflected light reflected from at least one of the supporting member and the detection target with a light-receiving unit; detecting a position of the detection target based on a difference between a reflection property of the supporting member to the detection light and a reflection property of the detection target to the detection light, wherein the light-emitting unit includes M number of light-emitting elements aligned in a direction that is inclined to a direction that is perpendicular to the predetermined direction, where M is equal to or larger than three, and the light-receiving unit includes N number of light-receiving elements aligned in a single direction, where N is equal to or larger than three, and wherein the detecting of the position of the detection target is performed based on output from the light-receiving elements.