AUTOMATIC FOCUSING SYSTEM.

摘要

The automatic sharp focusing system, focusses a beam sharply on to an image substrate. It consists of a semiconductor radiation source, (1) a sharp focusing element and a method of focusing the reflected section of the beam. There is a controlling element (9) which vibrates at a given frequency. The position of the spot is determined by a sharp setting element (8) in the direction of the optical axis. An oscillator excites the control element to a given frequency. There is also a phase detector for the output characteristics of the semiconductor source.