I guess the main confusion of defining this lens is probably the setting of depth/frequency. ROO*/OOd
'1<Z"InU
The main fresnel lens types are: Z:b?^u4.
OhF55,[
* Constant groove depth. 3CUQQ_
* Contant groove pitch types. Z[vx0[av&
M,Gy.ivz
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. P\7DA4]
S :HOlJze
Hope this helps!!