Hello everybody,
 
>    My understanding of the Leica system was that it moved the stage, =
>not the
>objective lens and was therefore limited to a very light object stage.  =
The
>inherent problem is the rapid movement, and then cessation of movement
>(damping), of a relative large inertial mass.=20
 
Just a comment from the manufacturer`s side (LEICA): There is absolutely
no problem with the rapid movement of Leicas z-stage for the confocal =
microscope. We are using it since 1988 in our confocal systems. The
design involves no gearbox with  related backlash. There
is a capacitive position feedback sensor monitoring constantly and =
extremely rapidly the actual z position. This sensor is part of a closed =
loop control electronics ensuring linear and  rapid z positioning. It is =
one of the big advantages of this stage that you can easily do xy OR xz =
sectioning at 13 frames per second with a re-positioning accuracy of 40 =
nanometers. The advantage is actually that the moving mass can be =
controlled, stopped and accellerated very rapidly. In addition, the =
stage has a relatively large travel range of 170 micrometers with a slim =
design, fitting it on various xy stages,
which is a problem for piezoelectric stages. The sample weight which
can be put on the stage is 250 grams.
 
Best regards
 
Martin Hoppe, Ph.D. =20
                                              =20
Leica Lasertechnik GmbH            WWW: http://www.llt.de/
Im Neuenheimer Feld 518             E-mail: [log in to unmask]
D-69120 Heidelberg/Germany