Bryan Mason bmasonatbmasondotcom wrote in message . ..
On Tue, 21 Sep 2004 22:45:00 GMT, Jon Kraus
wrote:

Get whatever you want but make sure that you get Non-polorized lenses.
It makes seeing your instruments easier.

Why is this? I know that polarized lenses cause weird problems with
LCD panels, but how do polarized lenses make the aircraft instruments
harder to see?

The glass or plastic covering the instrument dials often has a
polarizing coating to reduce glare. Just as you can use two
polarized pieces of glass together to block light, the two polariazed
glass in your sunglasses and the instrument dials can block your view
of the needles behind the dial's glass.

It depends on the polarization direction of your sunglasses and of the
dial's glass. If the same direction then no blockage. If the
directions are 90 degrees apart, you see black instead of the
instrument's display behind the glass. Take two old lenses from a
pair of polarized sunglasses and put one in front of the other. Look
through them and rotate one lens.

I accidentally tried this experiment as a student pilot once. In my
case if I held my head verticle with respect to the panel, I could see
all the gauges well except for one. I had to lay my head on my
shoulder to see that one, but then all the other gauges were black.
Awkward.

Some materials, like plastics, have a natural innate polarization.
Various coatings for anti-glare and such also have a polarization too.
Because of their general construction methods of layers of glass,
plastic and different coatings LCD panels are often polarized.

-Malcolm Teas
JYO