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design of XYZ scan system

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DINTINGER José

design of XYZ scan system

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Dear all,
I'm currently working on the design and fabrication of a cheap compact confocal microscope and I have a question regarding the design of the scanning system. For practical reasons, the ideal solution for me would be to keep the sample stationary and scan the laser beam focus in the XYZ directions.
After looking through the literature, I was thinking to use the standard design consisting of 2 closely spaced galvo mirrors for the XY scan , and move the objective in the axial direction for the Z stacks. However I am not sure whether these 2 approaches are compatible; from what I read it seems this is the case but there is a point that confuses me.
Indeed, the proper positioning of the galvo mirrors requires that their pivot point is imaged on the back focal (telecentric) plane of the objective via a scan lens and tube lens, meaning that the distance between the mirrors and the back focal plane of the objective must remain fixed. On the other hand, if I move the objective (independently) to adapt the Z-position of the focus, it would mean that the mirror-objective distance is changed...
I hope my question makes sense and I'd really grateful for any help.
Many thanks,
José

José DINTINGER
Research scientist
BioMEMS Section
---------------------------------------------------
CSEM Centre Suisse d'Electronique et de Microtechnique SA
Jaquet-Droz 1 | Case postale | CH-2002 Neuchâtel
www.csem.ch

Guy Cox-2

Re: design of XYZ scan system

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To join, leave or search the confocal microscopy listserv, go to:
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*****

José,

You are quite right about the problem. You just have to decide what compromises to make. Ideally both X and Y scan mirrors should be imaged on the BFP of the objective and several manufacturers have achieved this by appropriate optics, while others have just opted to have them close-coupled and accept the compromise. If you are now going to focus by moving the objective rather than the stage the risk of vignetting obviously increases. On possible 'solution' (or compromise) would be to introduce intermediate optics to make both scan planes telecentric so that then the objective movement is the only problem. I think you could get away with this in most cell biology cases.

Guy

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of DINTINGER José
Sent: Thursday, 25 July 2013 6:32 PM
To: [hidden email]
Subject: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Dear all,
I'm currently working on the design and fabrication of a cheap compact confocal microscope and I have a question regarding the design of the scanning system. For practical reasons, the ideal solution for me would be to keep the sample stationary and scan the laser beam focus in the XYZ directions.
After looking through the literature, I was thinking to use the standard design consisting of 2 closely spaced galvo mirrors for the XY scan , and move the objective in the axial direction for the Z stacks. However I am not sure whether these 2 approaches are compatible; from what I read it seems this is the case but there is a point that confuses me.
Indeed, the proper positioning of the galvo mirrors requires that their pivot point is imaged on the back focal (telecentric) plane of the objective via a scan lens and tube lens, meaning that the distance between the mirrors and the back focal plane of the objective must remain fixed. On the other hand, if I move the objective (independently) to adapt the Z-position of the focus, it would mean that the mirror-objective distance is changed...
I hope my question makes sense and I'd really grateful for any help.
Many thanks,
José

José DINTINGER
Research scientist
BioMEMS Section
---------------------------------------------------
CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz 1 | Case postale | CH-2002 Neuchâtel www.csem.ch

Peng Xi-2

Re: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Guy has explained it very clear. ONe thing to add: you may want that the
eyepiece image at the same focal distance with your confocal, so the
position of objective is fixed. If you only consider doing a z-section
within a few hunderds of microns, then you will find that the telescope
composed by the tube lens and the scan lens will give you such tolerance
(depth of focus) for you to do so, especially if you take the compromise
between the two close-by galvos.

Cheers,
Peng Xi
Ph. D. Associate Professor
Dept. of Biomedical Engineering, College of Engineering
Peking University, Beijing, China
Tel: +86 10-6276 7155
Email: [hidden email]

On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> José,
>
> You are quite right about the problem. You just have to decide
> what compromises to make. Ideally both X and Y scan mirrors should be
> imaged on the BFP of the objective and several manufacturers have achieved
> this by appropriate optics, while others have just opted to have them
> close-coupled and accept the compromise. If you are now going to focus by
> moving the objective rather than the stage the risk of vignetting obviously
> increases. On possible 'solution' (or compromise) would be to introduce
> intermediate optics to make both scan planes telecentric so that then the
> objective movement is the only problem. I think you could get away with
> this in most cell biology cases.
>
> Guy
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]]
> On Behalf Of DINTINGER José
> Sent: Thursday, 25 July 2013 6:32 PM
> To: [hidden email]
> Subject: design of XYZ scan system
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear all,
> I'm currently working on the design and fabrication of a cheap compact
> confocal microscope and I have a question regarding the design of the
> scanning system. For practical reasons, the ideal solution for me would be
> to keep the sample stationary and scan the laser beam focus in the XYZ
> directions.
> After looking through the literature, I was thinking to use the standard
> design consisting of 2 closely spaced galvo mirrors for the XY scan , and
> move the objective in the axial direction for the Z stacks. However I am
> not sure whether these 2 approaches are compatible; from what I read it
> seems this is the case but there is a point that confuses me.
> Indeed, the proper positioning of the galvo mirrors requires that their
> pivot point is imaged on the back focal (telecentric) plane of the
> objective via a scan lens and tube lens, meaning that the distance between
> the mirrors and the back focal plane of the objective must remain fixed. On
> the other hand, if I move the objective (independently) to adapt the
> Z-position of the focus, it would mean that the mirror-objective distance
> is changed...
> I hope my question makes sense and I'd really grateful for any help.
> Many thanks,
> José
>
> José DINTINGER
> Research scientist
> BioMEMS Section
> ---------------------------------------------------
> CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz 1 |
> Case postale | CH-2002 Neuchâtel www.csem.ch
>

Craig Brideau

Re: design of XYZ scan system

In reply to this post by Guy Cox-2

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*****

I agree with Guy as well. For most applications just keeping the XY galvo
mirrors as close together as practical should be good enough. All the
scanning systems I have modified or worked with used this approach and
there have been no problems with the results.

Craig Brideau
Hotchkiss Brain Institute
University of Calgary
On 2013-07-25 6:45 AM, "Guy Cox" <[hidden email]> wrote:

DINTINGER José

Re: design of XYZ scan system

In reply to this post by Peng Xi-2

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Dear all,

Thanks a lot for your help, that made things much clearer for me;
My project is just starting so I still have to sort out what are exactly the specs we are targeting and do some estimations to evaluate how the problem of vignetting is detrimental.

Really thank you, that was quite helpful... I'll probably come back to the LIST with some more questions!
Have a nice day.

José

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Peng Xi
Sent: jeudi 25 juillet 2013 15:05
To: [hidden email]
Subject: Re: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Guy has explained it very clear. ONe thing to add: you may want that the eyepiece image at the same focal distance with your confocal, so the position of objective is fixed. If you only consider doing a z-section within a few hunderds of microns, then you will find that the telescope composed by the tube lens and the scan lens will give you such tolerance (depth of focus) for you to do so, especially if you take the compromise between the two close-by galvos.

Cheers,
Peng Xi
Ph. D. Associate Professor
Dept. of Biomedical Engineering, College of Engineering Peking University, Beijing, China
Tel: +86 10-6276 7155
Email: [hidden email]

On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> José,
>
> You are quite right about the problem. You just have to
> decide what compromises to make. Ideally both X and Y scan mirrors
> should be imaged on the BFP of the objective and several manufacturers
> have achieved this by appropriate optics, while others have just opted
> to have them close-coupled and accept the compromise. If you are now
> going to focus by moving the objective rather than the stage the risk
> of vignetting obviously increases. On possible 'solution' (or
> compromise) would be to introduce intermediate optics to make both
> scan planes telecentric so that then the objective movement is the
> only problem. I think you could get away with this in most cell biology cases.
>
> Guy
>
> -----Original Message-----
> From: Confocal Microscopy List
> [mailto:[hidden email]]
> On Behalf Of DINTINGER José
> Sent: Thursday, 25 July 2013 6:32 PM
> To: [hidden email]
> Subject: design of XYZ scan system
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear all,
> I'm currently working on the design and fabrication of a cheap compact
> confocal microscope and I have a question regarding the design of the
> scanning system. For practical reasons, the ideal solution for me
> would be to keep the sample stationary and scan the laser beam focus
> in the XYZ directions.
> After looking through the literature, I was thinking to use the
> standard design consisting of 2 closely spaced galvo mirrors for the
> XY scan , and move the objective in the axial direction for the Z
> stacks. However I am not sure whether these 2 approaches are
> compatible; from what I read it seems this is the case but there is a point that confuses me.
> Indeed, the proper positioning of the galvo mirrors requires that
> their pivot point is imaged on the back focal (telecentric) plane of
> the objective via a scan lens and tube lens, meaning that the distance
> between the mirrors and the back focal plane of the objective must
> remain fixed. On the other hand, if I move the objective
> (independently) to adapt the Z-position of the focus, it would mean
> that the mirror-objective distance is changed...
> I hope my question makes sense and I'd really grateful for any help.
> Many thanks,
> José
>
> José DINTINGER
> Research scientist
> BioMEMS Section
> ---------------------------------------------------
> CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz
> 1 | Case postale | CH-2002 Neuchâtel www.csem.ch
>

Steffen Dietzel

Re: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

José,

just for completeness, there is a third option for scanning in xy:
When Davidovits and Egger (1969, 1971) built the first confocal laser(!)
scanning microscope, they used movement of the objective lens for
scanning. (Dois: 10.1364/AO.10.001615 and 10.1038/223831a0).
I guess there are reasons though, why this approach was not followed up
by later constructions.

Steffen

On 29.07.2013 10:13, DINTINGER José wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear all,
>
> Thanks a lot for your help, that made things much clearer for me;
> My project is just starting so I still have to sort out what are exactly the specs we are targeting and do some estimations to evaluate how the problem of vignetting is detrimental.
>
> Really thank you, that was quite helpful... I'll probably come back to the LIST with some more questions!
> Have a nice day.
>
> José
>
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Peng Xi
> Sent: jeudi 25 juillet 2013 15:05
> To: [hidden email]
> Subject: Re: design of XYZ scan system
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Guy has explained it very clear. ONe thing to add: you may want that the eyepiece image at the same focal distance with your confocal, so the position of objective is fixed. If you only consider doing a z-section within a few hunderds of microns, then you will find that the telescope composed by the tube lens and the scan lens will give you such tolerance (depth of focus) for you to do so, especially if you take the compromise between the two close-by galvos.
>
> Cheers,
> Peng Xi
> Ph. D. Associate Professor
> Dept. of Biomedical Engineering, College of Engineering Peking University, Beijing, China
> Tel: +86 10-6276 7155
> Email: [hidden email]
>
>
> On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox<[hidden email]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> José,
>>
>> You are quite right about the problem. You just have to
>> decide what compromises to make. Ideally both X and Y scan mirrors
>> should be imaged on the BFP of the objective and several manufacturers
>> have achieved this by appropriate optics, while others have just opted
>> to have them close-coupled and accept the compromise. If you are now
>> going to focus by moving the objective rather than the stage the risk
>> of vignetting obviously increases. On possible 'solution' (or
>> compromise) would be to introduce intermediate optics to make both
>> scan planes telecentric so that then the objective movement is the
>> only problem. I think you could get away with this in most cell biology cases.
>>
>> Guy
>>
>> -----Original Message-----
>> From: Confocal Microscopy List
>> [mailto:[hidden email]]
>> On Behalf Of DINTINGER José
>> Sent: Thursday, 25 July 2013 6:32 PM
>> To: [hidden email]
>> Subject: design of XYZ scan system
>>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> Dear all,
>> I'm currently working on the design and fabrication of a cheap compact
>> confocal microscope and I have a question regarding the design of the
>> scanning system. For practical reasons, the ideal solution for me
>> would be to keep the sample stationary and scan the laser beam focus
>> in the XYZ directions.
>> After looking through the literature, I was thinking to use the
>> standard design consisting of 2 closely spaced galvo mirrors for the
>> XY scan , and move the objective in the axial direction for the Z
>> stacks. However I am not sure whether these 2 approaches are
>> compatible; from what I read it seems this is the case but there is a point that confuses me.
>> Indeed, the proper positioning of the galvo mirrors requires that
>> their pivot point is imaged on the back focal (telecentric) plane of
>> the objective via a scan lens and tube lens, meaning that the distance
>> between the mirrors and the back focal plane of the objective must
>> remain fixed. On the other hand, if I move the objective
>> (independently) to adapt the Z-position of the focus, it would mean
>> that the mirror-objective distance is changed...
>> I hope my question makes sense and I'd really grateful for any help.
>> Many thanks,
>> José
>>
>> José DINTINGER
>> Research scientist
>> BioMEMS Section
>> ---------------------------------------------------
>> CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz
>> 1 | Case postale | CH-2002 Neuchâtel www.csem.ch
>>
>

--
------------------------------------------------------------
Steffen Dietzel, PD Dr. rer. nat
Ludwig-Maximilians-Universität München
Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
Head of light microscopy

Mail room:
Marchioninistr. 15, D-81377 München

Building location:
Marchioninistr. 27, München-Großhadern

Peng Xi-2

Re: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

That's because objective is hard to move -- it is bulky so one cannot move
it fast. That's why laser scanning becomes the mainstream.
Peng

On Mon, Jul 29, 2013 at 6:35 PM, Steffen Dietzel <[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> *****
>
> José,
>
> just for completeness, there is a third option for scanning in xy:
> When Davidovits and Egger (1969, 1971) built the first confocal laser(!)
> scanning microscope, they used movement of the objective lens for scanning.
> (Dois: 10.1364/AO.10.001615 and 10.1038/223831a0).
> I guess there are reasons though, why this approach was not followed up by
> later constructions.
>
> Steffen
>
>
> On 29.07.2013 10:13, DINTINGER José wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
>> *****
>>
>> Dear all,
>>
>> Thanks a lot for your help, that made things much clearer for me;
>> My project is just starting so I still have to sort out what are exactly
>> the specs we are targeting and do some estimations to evaluate how the
>> problem of vignetting is detrimental.
>>
>> Really thank you, that was quite helpful... I'll probably come back to
>> the LIST with some more questions!
>> Have a nice day.
>>
>> José
>>
>>
>> -----Original Message-----
>> From: Confocal Microscopy List [mailto:CONFOCALMICROSCOPY@**LISTS.UMN.EDU<[hidden email]>]
>> On Behalf Of Peng Xi
>> Sent: jeudi 25 juillet 2013 15:05
>> To: [hidden email].**EDU <[hidden email]>
>> Subject: Re: design of XYZ scan system
>>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
>> *****
>>
>> Guy has explained it very clear. ONe thing to add: you may want that the
>> eyepiece image at the same focal distance with your confocal, so the
>> position of objective is fixed. If you only consider doing a z-section
>> within a few hunderds of microns, then you will find that the telescope
>> composed by the tube lens and the scan lens will give you such tolerance
>> (depth of focus) for you to do so, especially if you take the compromise
>> between the two close-by galvos.
>>
>> Cheers,
>> Peng Xi
>> Ph. D. Associate Professor
>> Dept. of Biomedical Engineering, College of Engineering Peking
>> University, Beijing, China
>> Tel: +86 10-6276 7155
>> Email: [hidden email]
>>
>>
>> On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox<[hidden email]> wrote:
>>
>> *****
>>> To join, leave or search the confocal microscopy listserv, go to:
>>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
>>> *****
>>>
>>> José,
>>>
>>> You are quite right about the problem. You just have to
>>> decide what compromises to make. Ideally both X and Y scan mirrors
>>> should be imaged on the BFP of the objective and several manufacturers
>>> have achieved this by appropriate optics, while others have just opted
>>> to have them close-coupled and accept the compromise. If you are now
>>> going to focus by moving the objective rather than the stage the risk
>>> of vignetting obviously increases. On possible 'solution' (or
>>> compromise) would be to introduce intermediate optics to make both
>>> scan planes telecentric so that then the objective movement is the
>>> only problem. I think you could get away with this in most cell biology
>>> cases.
>>>
>>> Guy
>>>
>>> -----Original Message-----
>>> From: Confocal Microscopy List
>>> [mailto:CONFOCALMICROSCOPY@**LISTS.UMN.EDU<[hidden email]>
>>> ]
>>> On Behalf Of DINTINGER José
>>> Sent: Thursday, 25 July 2013 6:32 PM
>>> To: [hidden email].**EDU<[hidden email]>
>>> Subject: design of XYZ scan system
>>>
>>> *****
>>> To join, leave or search the confocal microscopy listserv, go to:
>>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
>>> *****
>>>
>>> Dear all,
>>> I'm currently working on the design and fabrication of a cheap compact
>>> confocal microscope and I have a question regarding the design of the
>>> scanning system. For practical reasons, the ideal solution for me
>>> would be to keep the sample stationary and scan the laser beam focus
>>> in the XYZ directions.
>>> After looking through the literature, I was thinking to use the
>>> standard design consisting of 2 closely spaced galvo mirrors for the
>>> XY scan , and move the objective in the axial direction for the Z
>>> stacks. However I am not sure whether these 2 approaches are
>>> compatible; from what I read it seems this is the case but there is a
>>> point that confuses me.
>>> Indeed, the proper positioning of the galvo mirrors requires that
>>> their pivot point is imaged on the back focal (telecentric) plane of
>>> the objective via a scan lens and tube lens, meaning that the distance
>>> between the mirrors and the back focal plane of the objective must
>>> remain fixed. On the other hand, if I move the objective
>>> (independently) to adapt the Z-position of the focus, it would mean
>>> that the mirror-objective distance is changed...
>>> I hope my question makes sense and I'd really grateful for any help.
>>> Many thanks,
>>> José
>>>
>>> José DINTINGER
>>> Research scientist
>>> BioMEMS Section
>>> ------------------------------**---------------------
>>> CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz
>>> 1 | Case postale | CH-2002 Neuchâtel www.csem.ch
>>>
>>>
>>
>
> --
> ------------------------------**------------------------------
> Steffen Dietzel, PD Dr. rer. nat
> Ludwig-Maximilians-Universität München
> Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
> Head of light microscopy
>
> Mail room:
> Marchioninistr. 15, D-81377 München
>
> Building location:
> Marchioninistr. 27, München-Großhadern
>

Craig Brideau

Re: design of XYZ scan system

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Indeed! Photons don't have mass. They do have momentum though... @;-)
Slewing around scan mirrors takes much less effort than moving a lens or
stage since it is rotary rather than linear motion. The devil in the
detail is accounting for the acceleration changes in the mirror slew rate
as it reaches the end of its traverse and has to go back the other way.
This is usually corrected by adjusting the acquisition timing as the
mirror approaches the edges. You can also just cut off the edges of your
field with a large square aperture thus removing the slow portion from your
scan, but this slows down your effective scan rate.

Craig

On Mon, Jul 29, 2013 at 5:16 AM, Peng Xi <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> That's because objective is hard to move -- it is bulky so one cannot move
> it fast. That's why laser scanning becomes the mainstream.
> Peng
>
>
> On Mon, Jul 29, 2013 at 6:35 PM, Steffen Dietzel <[hidden email]
> >wrote:
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> > *****
> >
> > José,
> >
> > just for completeness, there is a third option for scanning in xy:
> > When Davidovits and Egger (1969, 1971) built the first confocal laser(!)
> > scanning microscope, they used movement of the objective lens for
> scanning.
> > (Dois: 10.1364/AO.10.001615 and 10.1038/223831a0).
> > I guess there are reasons though, why this approach was not followed up
> by
> > later constructions.
> >
> > Steffen
> >
> >
> > On 29.07.2013 10:13, DINTINGER José wrote:
> >
> >> *****
> >> To join, leave or search the confocal microscopy listserv, go to:
> >> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> >> *****
> >>
> >> Dear all,
> >>
> >> Thanks a lot for your help, that made things much clearer for me;
> >> My project is just starting so I still have to sort out what are exactly
> >> the specs we are targeting and do some estimations to evaluate how the
> >> problem of vignetting is detrimental.
> >>
> >> Really thank you, that was quite helpful... I'll probably come back to
> >> the LIST with some more questions!
> >> Have a nice day.
> >>
> >> José
> >>
> >>
> >> -----Original Message-----
> >> From: Confocal Microscopy List [mailto:CONFOCALMICROSCOPY@**
> LISTS.UMN.EDU<[hidden email]>]
> >> On Behalf Of Peng Xi
> >> Sent: jeudi 25 juillet 2013 15:05
> >> To: [hidden email].**EDU <
> [hidden email]>
> >> Subject: Re: design of XYZ scan system
> >>
> >> *****
> >> To join, leave or search the confocal microscopy listserv, go to:
> >> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> >> *****
> >>
> >> Guy has explained it very clear. ONe thing to add: you may want that the
> >> eyepiece image at the same focal distance with your confocal, so the
> >> position of objective is fixed. If you only consider doing a z-section
> >> within a few hunderds of microns, then you will find that the telescope
> >> composed by the tube lens and the scan lens will give you such tolerance
> >> (depth of focus) for you to do so, especially if you take the compromise
> >> between the two close-by galvos.
> >>
> >> Cheers,
> >> Peng Xi
> >> Ph. D. Associate Professor
> >> Dept. of Biomedical Engineering, College of Engineering Peking
> >> University, Beijing, China
> >> Tel: +86 10-6276 7155
> >> Email: [hidden email]
> >>
> >>
> >> On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox<[hidden email]> wrote:
> >>
> >> *****
> >>> To join, leave or search the confocal microscopy listserv, go to:
> >>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> >>> *****
> >>>
> >>> José,
> >>>
> >>> You are quite right about the problem. You just have to
> >>> decide what compromises to make. Ideally both X and Y scan mirrors
> >>> should be imaged on the BFP of the objective and several manufacturers
> >>> have achieved this by appropriate optics, while others have just opted
> >>> to have them close-coupled and accept the compromise. If you are now
> >>> going to focus by moving the objective rather than the stage the risk
> >>> of vignetting obviously increases. On possible 'solution' (or
> >>> compromise) would be to introduce intermediate optics to make both
> >>> scan planes telecentric so that then the objective movement is the
> >>> only problem. I think you could get away with this in most cell
> biology
> >>> cases.
> >>>
> >>> Guy
> >>>
> >>> -----Original Message-----
> >>> From: Confocal Microscopy List
> >>> [mailto:CONFOCALMICROSCOPY@**LISTS.UMN.EDU<
> [hidden email]>
> >>> ]
> >>> On Behalf Of DINTINGER José
> >>> Sent: Thursday, 25 July 2013 6:32 PM
> >>> To: [hidden email].**EDU<
> [hidden email]>
> >>> Subject: design of XYZ scan system
> >>>
> >>> *****
> >>> To join, leave or search the confocal microscopy listserv, go to:
> >>> http://lists.umn.edu/cgi-bin/**wa?A0=confocalmicroscopy<
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>
> >>> *****
> >>>
> >>> Dear all,
> >>> I'm currently working on the design and fabrication of a cheap compact
> >>> confocal microscope and I have a question regarding the design of the
> >>> scanning system. For practical reasons, the ideal solution for me
> >>> would be to keep the sample stationary and scan the laser beam focus
> >>> in the XYZ directions.
> >>> After looking through the literature, I was thinking to use the
> >>> standard design consisting of 2 closely spaced galvo mirrors for the
> >>> XY scan , and move the objective in the axial direction for the Z
> >>> stacks. However I am not sure whether these 2 approaches are
> >>> compatible; from what I read it seems this is the case but there is a
> >>> point that confuses me.
> >>> Indeed, the proper positioning of the galvo mirrors requires that
> >>> their pivot point is imaged on the back focal (telecentric) plane of
> >>> the objective via a scan lens and tube lens, meaning that the distance
> >>> between the mirrors and the back focal plane of the objective must
> >>> remain fixed. On the other hand, if I move the objective
> >>> (independently) to adapt the Z-position of the focus, it would mean
> >>> that the mirror-objective distance is changed...
> >>> I hope my question makes sense and I'd really grateful for any help.
> >>> Many thanks,
> >>> José
> >>>
> >>> José DINTINGER
> >>> Research scientist
> >>> BioMEMS Section
> >>> ------------------------------**---------------------
> >>> CSEM Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz
> >>> 1 | Case postale | CH-2002 Neuchâtel www.csem.ch
> >>>
> >>>
> >>
> >
> > --
> > ------------------------------**------------------------------
> > Steffen Dietzel, PD Dr. rer. nat
> > Ludwig-Maximilians-Universität München
> > Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
> > Head of light microscopy
> >
> > Mail room:
> > Marchioninistr. 15, D-81377 München
> >
> > Building location:
> > Marchioninistr. 27, München-Großhadern
> >
>