NIGHT VIEWER WITH IMAGE INTENSIFIER TUBE

摘要

A night viewer (10) with an image intensifier tube (14) includes an improved power supply (62) which operates the image intensifier tube (14) according to a variable duty cycle either at a design voltage level for the tube or at a voltage level simulating a dark-field. This duty cycle variation is effected as a function of the current flow in the image intensifier tube (14) in order to provide automatic brightness control and bright source protection. Also, a microchannel plate (22) of the image intensifier tube (14) need not carry an ion barrier film, resulting in an improved light amplification for the image intensifier tube (14).