It is necessary to know the sunglasses parameters

1、UV（ Uv protection degree) The UV standard refers to the meaning of: the human eye to light the perception of the range is 380 ~ 780 nm ( The visible light) , is refers to under 380 nm wavelength ultraviolet light ( Not visible) 。 UV380 meaning is under 380 nm wavelength of the light can be effectively blocked. And standard UV400 because part also blocking the visible light, so will lose some colour. 2, plank, Plastic) Before the lap is a plastic sheet metal frame made of 3, memory ( Resistance to deformation) Refers to the frame of the resistance to deformation ability, polarization ( Polarized light, the polarization filter) Colour saturation, make the object contour become blurred, make the eye fatigue, discomfort. Polaroid is made according to the principle of polarization of the light, the light of the vibration plane and polarization parallel to the axis, the polarized filter to make the polarized light through ( As the principle of shutters) 。 Thus, the light is subdivided into light into the eye, the surrounding scenery looks clear and not dazzling. Add another prominent advantage is the extremely light and thin, The thickness of 0. 7毫米,1。 1毫米) And impact resistance, so this kind of lens is very suitable for driving and outdoor activities when wearing, in recent years by the vast number of consumers of all ages. Such as st.