Synonyms in a broader sense
Glasses, lenses, sunglasses
Definition
A pair of sunglasses is a pair of glasses with darkened, tinted lenses or lenses that alternately adapt to external light conditions. The production of the actual spectacle frame does not differ from that of normal vision spectacles. The only difference is in the manufacture of the lenses.
As a rule, no ground material is used for the lenses, but unground material, usually made of plastic. The plastic is colored with small color particles. Depending on how close together these molecules are, the tinting effect is also achieved.
Furthermore, there are also self-tinting spectacle lenses that are used both indoors and outdoors in different light conditions and adjust their tinting according to the lighting conditions. The lens reacts with the UV portion of the light. The reason for this are inclusions in the glass of silver and fluorine, chlorine, bromine or iodine.
The silver is the controlling factor here. In the dark it is in a certain charged form. When light rays hit the silver, the silver molecules take up electrons and are neutralized.
Neutralized silver molecules are more opaque and the lens turns darker. If the wearer is also short-sighted, the lens of a pair of sunglasses can also be ground in, i.e. the defective vision (long-sightedness or short-sightedness) is automatically corrected, and the sunglasses can also be used as distance glasses. Lenses can be made of real glass or plastic.
They are either colored directly during production (real glass) or afterwards (plastic). Instead of the classic brown/black coloring, it is also possible to color the sunglasses with different colors, which can give different color impressions in addition to the different filtering properties. For example, a lens tinted with light colors (e.g. yellow or orange) lets more light through than lenses tinted with green, brown or black. If you put on an orange or yellow tinted lens on cloudy days with low light exposure, you will feel the light exposure even more intense, the darker image of the outside world appears brighter.