GEODAETISCHES INSTRUMENT MIT LASER.

摘要

Radiation from a semiconductor laser (14) is directed upwards to a projectionlens (15). Above the lens, a porro prism (16) to provide an erected normal image is supported on a table (17) above the lens. The table is suspended by four plastics strings (19) which are disposed symmetrically relative to the upper surface of a support frame (18). By this arrangement the upwardly directed light flux is always parallel to the true vertical. Preferably the length of the ribbons suspending the table is equal to one half of the focal length of theprojection lens. To provide a horizontally-scanning beam a pentagonal prism (31) in a housing (32) is rotated by a motor (28), belt drive (30) and shaft (26). Theprism deflects the vertically-directed beam through ninety degrees of arc and scans it in the horizontal plane.