In order to understand the working principles of polarized sunglasses, let’s briefly discuss the reflection of light from the plain smooth surfaces. When light falls on a flat and smooth medium, the reflected light is directed in the horizontal planes rather than dispersing or scattering in all directions. The horizontally oriented reflected light is experienced as annoying flashes of white, known as glare. A prolonged exposure to such light intensities may result in temporary blindness.
In polarized sunglasses, a special filter is used that helps in eliminating the reflected light of high intensity or glare. In other words this polarized filter allows the passing of only a portion of light having wavelengths that are not aligned with the particles of the filter.
The composition of polarized filters are made up of a chemical compound coated on a transparent glass or plastic lens. The chemical film consists of tiny molecules that align in a parallel fashion with respect to one another.
If the chemical film is coated uniformly on the lens, the molecules absorb the entry of all light intensities that matches their alignment. Since glares are mostly caused by the horizontally oriented light waves, polarized sunglasses are designed in such a way that they allow passing of only vertical polarized light. With such polarized sunglasses, the texture and shape of objects become clearer, irrespective of the glare. This way, polarized lens reduce the glare effect.
One of the drawbacks of polarized sunglasses is that liquid crystal displays (LCD’) may not be visible while viewing at specific angles. This minor drawback weighs little against the advantages of glare free vision for such activities as driving, boating or any other outdoor activity. Recent advances in the development of more inexpensive chemical coatings has made these fantastic glasses more affordable and available to the cost-conscious consumer.