I guess the main confusion of defining this lens is probably the setting of depth/frequency. 7PR#(ftz
m/N dJMoN=
The main fresnel lens types are: !v]b(z`Y
JT
fd#g?I
* Constant groove depth. \5Vde%!$Z
* Contant groove pitch types. JbB}y'c4}=
I\qYkWg7
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. =)O,`.M.Y
1FtM>&%4
Hope this helps!!