Owen Gallagher
oweng@oweng.com
Wednesday, January 14, 1998


Application  Note for VOB Pro         Optimization of triplet lens system

Optimization of lens systems is a bit of a complicated process. There are many 
settings in the functions and parameters files in VOB Pro that control the 
optimization process. The details of the functioning are best learned by following 
examples.

In this example VOB Pro optimizes all radii of a triplet lens system. The initial 
lens system is the lentrp.os from the VOB example set. It is here as the 
lentrp00.os file.  The parameter and functions file and the version of this to 
be optimized are lentrp01.xxx files. The lens system after optimization is 
lentrp02.os. 

The optimization process can be followed during the run by opening spot and 
aberrations sub windows prior to starting the optimization run. 

It is interesting to note that after optimization the spot diagram clearly shows 
the central spot surrounded by a low intensity ring. This can be seen more clearly 
by disabling all but the on axis beam and then redisplaying the spot diagram. 

This optimization goes for 14 to 17 iteration and then stops with a constraints 
violation. At this point the optimization process is making minimal changes per 
iteration. This is the criteria for halting calculation.
