Re: Z-imaging with base motor instead of piezo.

Posted by Craig Brideau on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Z-imaging-with-base-motor-instead-of-piezo-tp7583864p7583880.html

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The tricky part with the electrically focusable lenses is implementing them
into existing systems. If you have a commercial microscope then finding a
good spot to insert them can be a little difficult. You might be able to
insert them between the objective and nosepiece if you have room. You also
need to synchronize acquisition with the lens setting which may not be
trivial depending on what signals you have access to in the system.

Craig

On Thu, Jun 18, 2015 at 10:52 PM, ANDREW EISENHAWER <[hidden email]>
wrote:

>
>
>
> Kurt, have you considered electrically tunable lenses for focus control
> rather than peizos or steppers?  I don't know much about them but I am sure
> others on the list could share their experiences. I would have thought
> these would be popular for issues like this (fast focus in thick specimems)
> if they preserved image quality.
> Q for the thread: Are they useable for high N.A. objectives?
> Andrew Eisenhawer
>
> Sent from my Samsung device over Bell's LTE network.
>
> -------- Original message --------
> From: Craig Brideau <[hidden email]>
> Date: 06-18-2015  3:53 PM  (GMT-07:00)
> To: [hidden email]
> Subject: Re: Z-imaging with base motor instead of piezo.
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
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>
> All my laser scanning systems use stepper motors for focus control, usually
> moving the objective rather than the stage. For video-rate imaging they are
> probably too slow, but if you are only doing a frame or two a second they
> work perfectly well. I have a collection of Nikon Ti frames with motorized
> focus, an old E800, and some Thorlabs stepper motors that all seem
> sub-micron repeatable. I would only resort to piezo if I was trying to
> acquire fast X-Z or Y-Z images. For the XYZ volumes typically collected in
> my lab the regular stepper motors are more than adequate.
>
> Craig
>
> On Thu, Jun 18, 2015 at 9:24 AM, Kurt Thorn <[hidden email]> wrote:
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > The microscope stand motor will generally be much slower than the piezo
> > insert, both because the long travel range makes it difficult to use a
> fast
> > piezo motor and because the mass that's being moved is much larger.  But
> > the precision of these stages can be quite good. The Nikon TiE can be
> > driven in steps as small as 25 nm; I'm not sure how accurate it is at
> those
> > step sizes, But I imagine it's pretty accuracte. Many years ago we
> acquired
> > Z-stacks with a 200 nm spacing with a stepper motor attached to the fine
> > focus knob of a microscope, and they seemed quite accurate, so accurate Z
> > motions can be achieved with pretty simple technology.
> >
> > Kurt
> >
> >
> > On 6/18/2015 1:22 AM, Anton Kamnev wrote:
> >
> >> *****
> >> To join, leave or search the confocal microscopy listserv, go to:
> >> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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> posting.
> >> *****
> >>
> >> Dear colleagues,
> >>
> >> In our LM core we normally use piezo stage inserts (e.g. PRIOR) for
> >> acquisition of Z-stacks. Those work fast and reliable but very have
> >> limited
> >> range (100~400 um). Moreover, stage inserts are often bulky and we
> >> experience a lot of problems fitting large specimens/slides into them.
> >>
> >> Obvious solution would be to get rid of piezo inserts and use base motor
> >> instead (which moves objective instead of sample). This would give more
> >> manoeuvre space at the stage and much bigger travel range. Unfortunately
> >> most of base motors are rather slow and often lack required precision.
> >>
> >> At the moment I’m looking into purchasing of new scope and thus
> wondering
> >> if
> >> there have been any advance in microscope base manufacturing.
> >>
> >> The question is - are there microscope bases which would move objective
> >> with
> >> speed and precision matching those of piezo inserts? If so, I would
> >> greatly
> >> appreciate if you could share your experience with those.
> >>
> >> Sincerely,
> >> Anton.
> >>
> >> Anton Kamnev, PhD
> >> Imaging Manager
> >> Mechanochemical Cell Biology Building
> >> Division of Biomedical Cell Biology
> >> Warwick Medical School
> >> The University of Warwick
> >> Coventry, CV4 7AL UK
> >> tel: [phone]
> >> cell: [phone]
> >> email: [hidden email]
> >>
> >>
> >>
> >
> > --
> > Kurt Thorn
> > Associate Professor
> > Director, Nikon Imaging Center
> > http://thornlab.ucsf.edu/
> > http://nic.ucsf.edu/blog/
> >
>