More attention to pick sunglasses

Sun glare, many people have to go out wearing cheap oakley sunglasses, glasses shops, jewelry stores, and shopping malls counters before purchasing sunglasses Customers also began to increase. Industry sources, in fact, very particular choice of sunglasses.
We must first understand the choice of sunglasses on the tag "uv400" logo, which is the ultraviolet wavelengths up to 400 nm, with this flag will be able to resist UV rays. In addition it also depends on sunglasses shading function, usually 2 to 3 for qualified products.
Polarized glasses lens surface is coated with a layer of polarizing film; reflective surface of the water can be filtered out, the car surface reflections and glare caused by specular reflection, suitable for use while driving，But the lenses darker, not suitable for light environments, which is less worn.
Screening Qualified lenses. Pick up the glasses against external objects are rotated through the lens to see whether the object is deformed, the best looking panes, door-like objects such as lines, curved lines, if found, color distortion badly, then the diopter lens failed, not buy. Furthermore, it should pay attention to the cheap oakleys lens surface is smooth; there should be no ripples, bubbles, Scar.
Also, pay attention to the lens colors, black, brown, gray filter is better, wearing gray lenses will darken the scene saw no obvious color, and wearing tinted lenses can improve visual contrast and clarity. Red lenses on some of the relatively short wavelength of light barrier is better, but other anti-
Whether facing the LCD screen look polarizer
The two lenses that are stacked together in 90 °, the intersection part will darken, and thus cannot see behind things (figure below). If the intersection is not dimmed, indicating that at least two glasses non-polarized sunglasses.
The glasses are on the LCD screen, then the lens does not change, then the glasses up to 45 ° angle clockwise when seen oakley sunglasses cheap lenses darken, then turn back to normal, which is polarized lenses. If no change no matter how rotation, it is not polarizer.
UV protection (uv400) Identification
Find a UV money detector light, a one hundred. Direct exposure can be seen above one hundred RMB UV security. If you have uv400 functions across the lens, you do not see security.