Optical position detection device and display device with position detection function

An optical position detection device adapted to detect a position of an object matter in a detection area, comprising:

• a first light source adapted to emit a first position detection light beam to the detection area to form a first intensity distribution of the first position detection light beam in the detection area;
• a second light source adapted to emit a second position detection light beam to the detection area to form a second intensity distribution in the detection area, the second intensity distribution having a highest intensity portion at a position shifted from a highest intensity portion of the first intensity distribution;
• a third light source adapted to emit a third position detection light beam to the detection area to form a third intensity distribution in the detection area, the third intensity distribution having a highest intensity portion at a position shifted from an imaginary straight line connecting the highest intensity portion of the first intensity distribution and the highest intensity portion of the second intensity distribution;
• a light detector adapted to detect the first position detection light beam, the second position detection light beam, and the third position detection light beam, reflected by the object matter in the detection area;
• and
• a position detection section adapted to detect a two-dimensional coordinate of the object matter in a detection plane set in the detection area, based on a result of comparison between an intensity of the first position detection light beam received by the light detector and an intensity of the second position detection light beam received by the light detector, and a result of comparison between an intensity of the second position detection light beam received by the light detector and an intensity of the third position detection light beam received by the light detector.