Understanding specular reflection.

Understanding specular reflection.

The lens of reflective sunglasses can reflect light like a mirror.

The lens is coated with a very thin layer of reflective paint-because this layer of paint is very sparse, it is called a semi-silvered surface.

The term "semi-silvered" comes from the fact that the reflective molecules on the lens are very sparse, and the number is only about half of the number of molecules when the lens becomes an opaque mirror.

At the molecular level, the reflective molecules are evenly dispersed on the surface of the lens to form a uniform film, but only half of the area of the lens is covered by the film.

This half of the silver-plated surface can reflect about half of the light that reaches its surface, and let the other half of the light directly pass through.

Usually, the mirror paint is gradual, and the color depth of the paint gradually changes from top to bottom.

This can enhance the resistance of sunglasses to light from above, while allowing more light to enter from below and horizontally.

This means that when you are driving, sunglasses can block the sun's rays while also allowing you to see the dashboard clearly.

Sometimes, the paint is double gradient, the upper and lower parts of the lens have the highest color depth, and the middle of the lens is clear.

The key problem with reflective sunglasses is that the paint is easily scratched.

Obviously, today's sunglasses manufacturers have not been able to successfully coat the surface of the reflective film with an anti-scratch layer.

Therefore, the anti-scratch layer is coated on the surface of the lens, and the reflective film is coated on the anti-scratch layer.