Although the above technical decription serves well to inform us - it does sound as if some issues are not addressed:
The fact that the green light "speads" or "dillutes" is comforting until one discovers that the wind shield has a few "scratches" that causes it to suddenly become completely green. Unlike you car where the problem of an oncoming vehicle not dimming their head lamps?
Check this thread from the rotor heads:
http://www.pprune.org/forums/showthread.php?t=320314
HansFlyer