I guess the main confusion of defining this lens is probably the setting of depth/frequency. uC]c`Ue
D=f$-rn
The main fresnel lens types are: 2Z9ck|L>
=OrVaZ0
* Constant groove depth. +Lr`-</VF
* Contant groove pitch types. )*}?EI4.
dF&@q,
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. ZlMS=<hgFx
#|V)>")
Hope this helps!!