Ever Wonder How Sunglasses Are Made?
Sunglasses are fashionable accessories that are fun to wear, protect your eyes and make you look cool. The come in many differently colors, brands and styles. They come as clip-ons, polarized, prescription, unisex, designer, and custom made. Sunglasses are also specialized for policemen, pilots, rescue workers, skiers, and bikers. You can even buy sunglasses with built in digital music players!
Not only are styles different, but the lenses in sunglasses vary also. Lenses made of glass provide better visual quality and are also more scratch resistant. Photo chromic lenses darken and lighten according to the brightness of the environment. Glass photo chromic lenses provide the most efficient reduction of UV rays. Lenses known as gradient lenses are lighter on bottom and gradually darken towards the top of the lens. Lenses can be tinted almost any color.
Different colored lenses provide different levels of UV ray protection. Amber and brown do the best job of absorbing UV rays. One can also treat clear lenses with special anti-reflective coating and that will shield eyes from ultra violet radiation. The highest level of UV protection is of course 100%. This anti-reflective coating also protects the lenses from scratches.
Before the tinting is applied, the lenses first need to be fitted into the sunglasses frame so the lens has to be ground to fit the shape and size of the frame. And if the sunglasses are prescription, they will also need to be ground according to the prescription. One might need prescription sunglasses for myopia and for bifocals and trifocals.
The grinder used to bring the lens into specification is called an edger. When the edger is in use there is a steady stream of water running across the lens to reduce heat cause by the friction from grinding. If water is not used, the glass can break from the intense heat. Water also makes it easier to grind and results in a smoother edge without scratching caused by dry grit.
When the grinding is finished, the lenses are cleaned and then tint is added by dipping the lens into the tint solution which then becomes absorbed into the lens. The longer the lens is left in the tint, the darker the color will be. The lenses are then rinsed completely and left to dry. They are fitted into the frame of the sunglasses. The fit is made secure by tightening small screws in the frame. The frames of sunglasses are mass produced from such products as nylon, carbon fiber, plastic, or metal.
The making of sunglasses has advanced quite a bit since the days of Nero. He fashioned sunglasses by holding polished emerald glass in front of his eyes.
