Mirror Sunglasses: How Do They Work?

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Mirror sunglasses function by utilizing a reflective coating that creates a one-way visibility effect, similar to how a darkened room appears. The interior of the sunglasses is typically darker than the outside environment, allowing wearers to see out while preventing others from seeing in. The discussion also explores the theoretical implications of combining a half-silvered mirror with a neutral density filter, which could affect visibility from both sides. This combination could result in varying levels of reflection and transmission, contributing to the unique functionality of mirror sunglasses. Understanding these principles clarifies how mirror sunglasses operate in different lighting conditions.
daniel_i_l
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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.
 
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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.
 
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?
 
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.
 
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.
 
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