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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 <[log in to unmask]>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<[log in to unmask]>]
>> On Behalf Of Peng Xi
>> Sent: jeudi 25 juillet 2013 15:05
>> To: [log in to unmask]**EDU <[log in to unmask]>
>> 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: [log in to unmask]
>>
>>
>> On Thu, Jul 25, 2013 at 7:53 PM, Guy Cox<[log in to unmask]>  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<[log in to unmask]>
>>> ]
>>> On Behalf Of DINTINGER José
>>> Sent: Thursday, 25 July 2013 6:32 PM
>>> To: [log in to unmask]**EDU<[log in to unmask]>
>>> 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)
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