Sorry, my PC cannot type chinese now, crazy. ^L,K& Jd
+X\FBvP&
I saw some Japanese engineers use "primary differential and second differential" to define the extended freeform optical surface tolerance. 8$]1M,$r
I guess it define some vatied range for each coefficients but I don't know Japanese words. kl"hBK#D%
Still cannot know how to do that.