Mirror Sunglasses: How Do They Work?

[daniel_i_l]

How do mirror sunglasses work? I used to think that they worked like "one way mirrors" but those are just half silvered glass - meaning that if you are standing in a bright room looking through it into a dark one you'll see your reflection but if you look from a dark room into a light room you can see through. But I noticed that with the mirrored sunglasses you can only see "out" no matter how the lighting is set up. So how do they work?
Thanks.

 

[mgb_phys]

They are as you say exactly like a darkened room. Rememebr that the 'room' behind them (between them and your eyes) is always likely to be darker than the room in front on them.

 

[daniel_i_l]

Yes, but even when I take the glasses off and hold them a few meters a way from me I can only see in one direction. How can that be?

 

[cesiumfrog]

What would happen if you sandwiched a half-silvered mirror against a neutral density filter?

From one side you would see a half-reflection which swamps a half-transmitted plus attenuated image. From the other side you would see a once-attenuated half-transmission superimposed on a twice-attenuated half-reflection. I don't know the construction of your particular sunglasses, but this would be a way of obtaining the effect you describe.

 

[Danger]

Thanks a lot, Froggie. I've been planning my supper for the past 2 hours, and your last post made me so dizzy that I can't eat.