Anti-dazzle mirror - how do they work?

AHAR

Hi,
You know those rear view mirrors with the lever to manually switch to anti-dazzle mode? How does that work then?
I've wondered for a while what's going on mechanically inside and what it is that changes/moves in there. I've noticed that if you duck your head down low when they're set to 'normal' mode, you can see the same reflection as if you'd had your head in the normal position only dimmer. I'm sure someone here will know...
Thanks.

anewman

It's just to do with the way the bits are all angled. In anti-dazzle you get a reflection that isn't straight off the mirror glass inside, so high beams don't reflect straight off the mirror into your eyes.

beniamino

Interesting question. Turns out the mirror is wedge-shaped and the anti-dazzle setting uses the reflection off the front surface of the glass. More info here:

http://auto.howstuffworks.com/question20.htm

AHAR

Thanks beniamino. I get it now!