US Patent 9810882 Optical lens

An optical lens includes seven lenses. An first lens has a negative refractive power: an second lens, an third lens, an fifth lens, an sixth lens and an seventh lens have refractive powers respectively, and the fourth lens has a positive refractive power. One of the second lens and the third lens has a positive refractive power, and the other has a negative refractive power. One of the fifth lens and the sixth lens has a positive refractive power and the other has a negative refractive power. An object-side surface of the first lens has a refractive rate R1, an image-side surface of the first lens has a refractive rate R2, and |R2/R1|≦0.01.