It is a kind of optical lens features, the refractive index of light by air into the lens material deviate from its original value of the path.
Lens refractive index is divided into: 1, the average refractive index: 1.
48 ~ 1.
2, the refractive index: 1.
56 ~ 1.
3, high refractive index: 1.
4, high refractive index: greater than 1.
2, dispersion force dispersion is light in a medium propagation velocity v vary with wavelength of the phenomenon, namely medium refractive index difference of two different light;
High dispersion force often make lens produces chromatic stripe around, causing discomfort;
In eye optometry abbe coefficient reflects the lens material is commonly used in the dispersion force.
Three, reflective lens surface will produce reflection phenomenon, affect the lens sharpness.
For the lens, the higher the refractive index, reflectivity, the greater the losses from reflection of light, the more the Dai Jingzhe see virtual image or make the lens produces glare decreasing contrast, etc. , shall generally be plated multilayer minus reflection film on the lens.
Four, the light absorption often referred to as the glasses materials absorb light, achieve the goal that reduce the amount of light incident;
General dyeing and light color lenses have this function.
Five, the light transmittance is light through the lens is not reflection and absorption of visible light transmittance, the lower the average refractive index, the higher light transmittance.
Six, uv cut off uv cut reflects the material blocking the wavelength of ultraviolet radiation through the ability.
A and UV -
B has great harm to human eyes.
Generally can be absorbed by the atmosphere, thus generally ignored.
315 ~ 380)
280 ~ 315)
Seven, physical properties including the lens of density, hardness, impact resistance and static deformation and so on, mainly embodies the impact and abrasion resistance of the lens.