Sunglasses measurements: the light transmittance

Light transmission than project is an important index to present the function of sunglasses, light transmittance is refers to the transmission flux and the ratio of the incident light flux, this ratio represents a lens (in the wavelength range Medium) In the amount of light through the transmittance, can also be understood as irradiation light ( Like the sun) In the lens through the quantity, it reflects the shading effect lens. Our current product standards according to the function is divided into three categories: shade, light color sunglasses and special-purpose sunglasses lens, and GB10810. 3 transmittance standards and measurement standards will be subdivided into four categories. QB2457 - 1999 'sunglasses' standard regulation: A. Light color sunglasses light transmittance for & gt; 40%; B。 Sunshade sunglasses light transmittance was 8% ~ 40%; C。 Special-purpose sunglasses light transmittance was 3% ~ 8%. It is not hard to see from A class to class C is the color of the sun glasses, in turn, from shallow to deep, also can say the lens is, in turn, strengthen the ability to filter. The light of the different types of sunglasses transmittance must strictly comply with the above requirements. Category is different, use different sunglasses. 1. Sunglasses class transmittance requirements. 2. Driving with transmittance demanded to see the ISO14889 lens, the traffic signal identification ( Packing mark) Shall meet the following requirements: ( 1) Light transmission than driving with mirror light through than the rv shall not be less than 8%. Daily driving glasses: under the condition of using the standard illuminant D65, its design reference point ( Or geometric center) Place the light transmittance of the rv must be greater than or equal to 75%. ( 2) The spectral transmittance in ( 5, 000-650) Nm at any wavelength in the range of spectral transmittance r ( λ) Not less than 0. 2rv。 ( 3) Red traffic lights to identify the relative visual attenuation factor Q: 0 or higher. 8; Yellow: 0 or higher. 8; Green: 0 or higher. 6; Blue: 0 or higher. 4. ( 4) With special function driving mirror besides should meet the requirements of national standard for sunglasses, still should satisfy both manufacturers indicated the special function of technical indicators.