Sorry, my PC cannot type chinese now, crazy. =Uk#7U"P
>MYxj}I4{z
I saw some Japanese engineers use "primary differential and second differential" to define the extended freeform optical surface tolerance. f1NHW|_j
I guess it define some vatied range for each coefficients but I don't know Japanese words. |gkNhxzB
Still cannot know how to do that.