Flat-convex silicon lens Precision (the highest) : N=2 , N=0.5 , B=40/20 , C=0.01 Flat-convex silicon lensMaterial : Monocrystal line silicon N shape. resistivity : 5-40Ω, crystallographic orientation 111 Specification : Φ6-Φ22 , Center thickness=1.5-2.5mmPrecision (the highest) : N=2 , N=0.5 , B=40/20 , C=0.01Output : 200K/month