I guess the main confusion of defining this lens is probably the setting of depth/frequency. M6(o J*
B<.XowT'
The main fresnel lens types are: c&zZsJ"~
@V$,H/v:
* Constant groove depth. =[Lo9Sg
* Contant groove pitch types. -fF1vJ7L
qGndh
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. |12Cg>;j*n
>z0~!!YZ
Hope this helps!!