POSITION DETECTOR FOR TRAVELING OBJECT

摘要

PURPOSE:To detect angles of triangulation with high accuracy and to know accurately the position of a traveling object itself by detecting directly the light given from a fixed light emitting part having a spot light source with a group of photodetecting elements which are arranged in a semicircumference through a slit plate having a magnet. CONSTITUTION:A traveling object 1 contains an incident angle detector consisting of a cylinder having on its inner wall the groups 7 and 8 of photodetecting elements arranged in a semicircumference and a full circumference, a slit 9a supported by a pivot on the same axis as said cylinder and a slit plate 9 having a magnet and a light emitting element 10 opposite to the reference point of the group 8. The incident angle detector delivers signals (a) and (b) to a photodetector 24. These signals (a) and (b) correspond to incident angles theta1 and theta2 of the light which is made incident to the group 7 from spot light source transmission parts 2 and 3 set on an external field wall surface D which is parallel to N-S of earth magnetism with a distance through the slit 9a. The detector 24 converts the signals (a) and (b) into binary data (f) and (g) and supplies these data to cosine circuits 16-19. Then a prescribed operation is carried out to detect the distance L between the object 1 and the substrate D. Thus both angles can be simultaneously detected in the triangulation. Thus an accurate position of the object 1 is recognized.