I guess the main confusion of defining this lens is probably the setting of depth/frequency. s;<]gaonB_
%QDAog
The main fresnel lens types are: 4UL"f<7 T
4t*VI<=<[
* Constant groove depth. Kk.\P|k2
* Contant groove pitch types. ]\ZJaU80I~
MYJDfI
So if your depth is fixed you will define +ve value in the cell and to specify the "height" or "depth" of each groove feature. If the frequency of the groove is fixed then you use -ve value. Say putting down - 5 this implies that there are 5 grooves with a unit length. J|V*g]#kP
IwXQbJ3v_
Hope this helps!!