Sunglasses with UV protection are due to the addition of a special coating on the lenses, and inferior sunglasses not only cannot block UV rays, but also seriously reduce the transmittance of the lenses, making the pupils larger, and ultraviolet rays will be injected in large quantities, causing damage to the eyes. . So today, IVision optical will take you to understand: how to know whether sunglasses are prevent UV-resistant?
Method 1. Look at the label of the sunglasses.
Visible signs such as "UV protection", "UV400", etc. are seen on the labels or lenses of UV-resistant sunglasses. "UV index" is the effect of filtering out ultraviolet rays, which is an important criterion for purchasing sunglasses. Light with a wavelength of 286nm-400nm is called ultraviolet light. In general, a 100% UV index is impossible. The UV index of most sunglasses is between 96% and 98%.
Sunglasses with anti-ultraviolet function generally have the following express ways:
a) Mark "UV400": this means that the cut-off wavelength of the lens to ultraviolet light is 400nm, that is, the maximum value τmax (λ) of the spectral transmittance at the wavelength (λ) below 400nm is not more than 2%;
b) Mark "UV" and "UV protection": this means that the cut-off wavelength of the lens to ultraviolet is 380nm, that is, the maximum value τmax(λ) of the spectral transmittance at the wavelength (λ) below 380nm is not more than 2%;
c) Mark "100% UV absorption": This means that the lens has a function of 100% absorption of ultraviolet rays, that is, its average transmittance in the ultraviolet range is not greater than 0.5%.
The sunglasses that meet the above requirements are the sunglasses that protect against ultraviolet rays in the true sense.
Method 2. Use banknote pen to check verify
In the absence of instruments, ordinary people can also detect whether the sunglasses have UV protection. Take a banknote, put the sunglasses lens on the anti-counterfeiting watermark, and take a photo on the lens with a money detector or a money detector. If you can still see the watermark, it means that the sunglasses are not UV-resistant. If you can't see it, it means The sunglasses are UV protected.
To sum up the above: Method 2 is a verification of the sunglasses label in Method 1. It can be roughly seen whether the merchant's label is correct and whether the sunglasses have the function of anti-ultraviolet. When shopping for sunglasses, you can try them out. In the process of purchasing and wearing, if you have any questions, please browse for more relevant information.
Post time: Jul-22-2022