subject: What Is Polarized Sunglasses [print this page] UV damage to human body, has the" cumulative", that is exposed to the sun over time, ultraviolet harm is greater. The United States has a statistical report, a personal life from ultraviolet light exposure, eighty percent of which are in the eighteen years prior to exposure to the sun are cumulative, so avoid ultraviolet harm, must start from childhood. Parents should teach children the right idea, develop from wearing sun glasses habits, reduced UV damage in the eyes of the cumulative. Selection of sun glasses, not that of the deep color of the lenses, UV resistant effect is stronger. In contrast, color is deeper but will make the pupil becomes greater and greater, if not safe UV lens, the eye will irradiate the ultraviolet, the harm will be more powerful.
So it is best to confirm lens can effectively block more than 99% of the UV ( including ultraviolet A and ultraviolet B ), at the same time with polarizing properties, so as to eliminate glare ( glare is from some angles of light reflected to the eye will make people temporarily not clear thing ), polarized glasses lens more polarizing angle of science. In order to meet these stringent optical requirements, responsible manufacturers often have to invest huge amounts of money, personnel and equipment to design and manufacture it. There the sun glasses quality difference is very big, the price also as different as heaven and hell, which is the reason why!
To avoid the damage caused by UV eye, of course we should try to reduce exposure to strong sunlight, especially in the morning10to 2 pm, at the period of direct sunlight in the surface of the earth, the highest UV intensity. Especially those by cement, sand, snow or water surface reflection of ultraviolet light, and belongs to the most powerful force, causing eye injury is also the largest, but it is the most easily overlooked. Therefore, to these in place long time activity, be sure to wear appropriate polarized sun glasses.
The principle of polarized sunglasses:
Natural light ( unpolarized light ), is actually made of will in a particular direction vibration waves, while being reflected or scattered light and usually have a preference for a particular direction, which is why the polarizing sunglasses can filter out from the roof or sump reflection to sun 's sake; natural light passes through the polarizing lens after filtration, can let a direction of light through, that is polarized lenses can be light polarized, allows only one direction through light ( visible light ).
Polarized sun glasses is the use of this characteristic to block the harmful rays, because the sun either touch any object will be due to natural reflection or refraction produces harmful dazzle, polarized sunglasses can completely absorb these will create the dazzling glare and eye injuries.
The general Sunglasses with polarized sunglasses comparison:
General sun glasses using only light reduction effect, because the general lens cannot be filtered light, so can reduce the glare of light, the intensity, and can not be completely blocking the harmful light, so its function is to reduce injury of the eye, but the general sun glasses is the biggest advantage of pop. Polarized lenses due to having the polarizing properties, so it can be completely separated due to scattering, inflectional, reflection and other factors caused by the dazzling glare. At the same time can also be harmful ultraviolet light to the eyes are completely separated, so that the people in the light of long-term activities, eyes tired easily, achieve the true protection function, and can see things more clearly, stereo.
The function of polarized sunglasses:
In life, there are too many light source can produce harmful rays, especially the sun light; the sun sends out light: visible light, infrared, ultraviolet, three ( Figure 5). In ultraviolet on human skin, eyes.., causing serious injury; sun released light IR ( Infra-red ) (750mm ) above the infrared, visible light ( Visible light lay ) (310 ~ 780nm ); ultraviolet is divided into UVA, UVB, UVC (310nm ), blue ( Blue light UVA, UVB, UVC ) which are harmful light, if long time exposure can cause physical damage, UVB is the vision has a severe impact on ( Tanning, Ray ) is burned black skin and light eyes, most will absorb the UVB light so be sure to block out the light source. Polarized sunglasses because has the light polarization functions, so will all the harmful rays are blocked off but does not affect the visible light transmittance, can really achieve the eye protection function.
Application of polarized sunglasses:
Polarized sunglasses for100% block the harmful rays, so it can be used in:
1: the eye operation patients, medical needs all-around protection, polarized sun glasses is the best choice.
Outdoor activities such as skiing,2: fishing, water sports, all need to completely block the harmful rays of the sun glasses, in order to avoid eye injuries or fatigue.
The 3goggles
The types of polarized sunglasses:
So how to choose polarizing sunglasses? The different colors of polarized sun glasses, each with different characteristics. Light red or scarlet lens, in the case of glare is very strong, can deepen the contrast and brightness, very suitable for water sports and snow activity using. Brown or brown lens, because can enhance the contrast of colour, so become the driving of the preferred lens. Amber color, yellow or orange lens, cloudy day wearing very fit, can have very clear vision, but not suitable for use under the sun. Grey or dark green lens, depending on the material can retain the original color of nature, is a good choice.
Sun glasses are not only in the summer to be worn all year round, is actually must use. Fine to wear, cloudy day to wear. Don't think that cloudy sun light is not strong, the weather is not hot, they let down, imperceptibly but more harmful ultraviolet irradiation. So even if the thin cloud cloudy, still must reference the UV index forecast, good sunscreen preparations.
