POSITION MEASURING INSTRUMENT AND POSITION INPUT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a position measuring instrument which has good operability and is inexpensive and can accurately measure a position. SOLUTION: Two photodetecting elements 2 and 3 are provided in one measurement unit. The photodetection surfaces of the photodetecting elements 2 and 3 have their center axes on the straight line nearly perpendicular to a two-dimensional plane as an object to be measured and are arranged one over the other while having an opening angle of 90 deg.. Two photodetecting elements 4 and 5 of another measurement unit are the same. The photodetecting elements 2 to 5 photodetect the light from a light source 1 and outputs photodetection quantities. The photodetecting elements 2 and 3 or 4 and 5 in the measurement unit have their center axes crossed and then errors of distances from the light source 1 cancel each other, so that a computation part 6 can accurately compute the position of the light source 1.