Patent ID: 6150650
Filing Date: 2000-11-21
Classification: G02B

Abstract:
In a night vision device including an image intensifier tube having a given life expectancy, and being subjected to factory calibration for providing an optimum output during operation, wherein said calibration undesirably differs from tube to tube and is adjustable by at least one variable resistor coupled to the tube, whereby when one tube is substituted for another, said difference in calibration causes non-optimal performance, a method for providing a user adjustable variable gain for said night vision device such that said variable gain is substantially insensitive to tube substitutions, comprising the steps of:determining a minimum gain limit and maximum gain limit associated with said optimum output of said night vision device;substituting said at least one variable resistor with a gain limiting circuit, and factory calibrating said second gain limiting circuit according to said minimum and maximum gain limits, wherein said gain limiting circuit and corresponding gain limits are associated with said image intensifier tube; and,tethering said gain limiting circuit to said image intensifier tube.