T3D Re: Polarized Headlamps (TECH-3D digest 380)

[bobh@xxxxxxxxxxxxxxxxxx]

RE: When I was at Westinghouse Lamp Division as an engineer in 
photolamps...we had a lot of those headlamps with Polarized filters 
built in for testing in our Autolamp group.  The idea of course was 
that if you had polarized lamps and polarized windshields crossed, 
(as in one eye blocked for Stereo projection to make this legal?) 
then the oncoming headlamp would be just a nice white disc and 
not blinding. The catch that killed the whole thing was that the light 
output had to be increased for the heavy filter factor of the polarizer  
in both the lamp and windshield. IF ALL CARS were equipped it 
would be no problem but very blinding to a car with ordinary 
windshield. They thought that a visor type filter could be sold to 
cars without the windshield, but no way to insure all cars would be 
fitted..and the filtered windshield also dimmed night viewing. 
So it all fell to the wayside as too expensive and impractical to 
make universal.  BobH
Bob Howard (bobh@xxxxxxxxxxxxxxxxxx)
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