Basic knowledge of sunglasses: the main form of optical radiation protection
Sunglasses in addition to can reduce the radiation intensity of visible light, can also reduce the ultraviolet and infrared radiation. Polarized sunglasses can also be used to eliminate the water, snow, reflecting the gravel road surface level. Sunglasses cash more endowed with fashionable breath. But the fundamental role of sunglasses is to provide radiation protection for the eyes. On the basic requirement of sunglasses are: eliminate unwanted radiation may have damage to the eyes; Reduce the environment light intensity into eyes, provide clear, comfortable functional vision; Can maintain normal color vision, reflected in the rapid and accurate identification of traffic lights; Maintaining quantity dark adaptation or night vision; Shock resistance and good wear resistance performance. To introduce the basic knowledge of the sunglasses below the main form of optical radiation protection. 1. For uv protection human accept ultraviolet radiation mainly comes from the nature. Ozone layer depleting makes for uv protection is particularly important for ultraviolet (uv) radiation optical protection mainly take the principle of absorption, polarization interference filter to remove excess radiation. Uv eye tissue damage should be brought to the attention of the extensive lost people in outdoor activities or is engaged in the special work such as welding, also should have the consciousness to choose glasses or contact lenses with uv filter functions, to ensure the health of the eye. Without crystal patients, should choose the artificial lens can absorb ultraviolet light, make sure that the retina from damage. Now commonly used in protective measures is a framework with ultraviolet absorption mirror, sunglasses, contact lens, artificial crystal. 2. Protection of the infrared radiation of infrared protection is to use the vacuum plating mirror type metal film layer. Again in the form of heat absorption lenses will IR radiation, easily through eye organization to reach the retina. Commonly used metal film layer is gold, silver, copper and aluminum. Compared with the corresponding radiation wavelengths, membrane thickness should be as small as possible, the thickness will reduce the reflection. When considering of infrared protection can be combined with ultraviolet light and other radiation protection. 3. To visible light protection of excessive visible radiation protection mainly adopts the sunglasses. For clear, comfortable vision, 1 370 CD/m2 ( 400英尺L) The brightness is ideal. This is so in full under the shade of light intensity of the sunshine. Sunglasses with light transmittance and optical density, in industry are also useful light coefficient ( 阴影号) To represent. Light coefficient and optical density as follows: the relationship between light and shadow coefficient of + 1 = 7/3 optical density. Sunglasses will make the optical density 1. O above.