DEVICE FOR MEASURING THE INTENSITY OF A SCANNING LIGHT BEAM BY MEANS OF A LIGHT CONDUCTING ROD

摘要

A device for measuring the intensity of a scanning light beam moving in a preferably plane face, having a transparent light-conducting rod having a front and back end and being mounted in said plane face substantially parallel to the direction of scanning of the light, the rod conducting at least one portion of the light which impinges thereupon and enters therein toward the front end by reflecting on the walls of said rod; a photoelectric receiver mounted adjacent the front end of the rod for transforming the light current reaching the front end of the rod into an electrical signal; a light-reflecting surface extending along the light-conducting rod in spaced relation on the side of the rod opposite the area of light impingement on the rod; a series of separate screens extending along the axis of the rod and interposed between the light reflecting surface and the rod, each screen being adjustable transversely of the longitudinal axis of the rod such that each screen influences in a different manner that portion of the light emerging laterally from the walls of the rod and reflected back into the rod by the light reflecting surface according to the adjustment of the respective screen as to the portion of the light reflecting surface exposed to the rod and not blocked by the screen according to the adjustment of the screen.