Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Good point. You'd also have to align two sets of galvometric mirrors  
to each other (more $$$) and make sure that they scan the same way.  
Someone else just pointed out that this can be solved by using a  
stage-scanning system, however. But I think Andrew Resnick pointed  
out a better reason for there not being a transmission pathway pinhole.

John

On 6-Nov-07, at 10:43 AM, Michael Weber wrote:

> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> But how do you de-scan in the transmission beam path? You would  
> need a second scanner behind the condenser which has to be  
> synchronized with the main one, to bring the light to the pinhole.
>
> cheers,
> Michael
>
>
> John Oreopoulos wrote:
>> Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/ 
>> cgi-bin/wa?S1=confocal This is a good question and I've wondered  
>> why the commercial systems don't have a transmission pinhole as  
>> well. I'm sure it must be possible because I think Minski's  
>> original confocal microscope had a transmission optical design.  
>> It's possible to form reflection confocal images with the  
>> backscattered laser light if you remove the emission filters in  
>> front of your detectors, and there isn't any tricky pinhole  
>> alignment associated with that. Perhaps that is the main reason -  
>> a transmission pathway pinhole would have to be aligned to the  
>> system and this might be difficult to maintain. In the epi  
>> configuration, the objective also acts as the condenser, whereas  
>> in the transmission pathway you have to align the objective, the  
>> condenser, and a pinhole.
>> John Oreopoulos, BSc,
>> PhD Candidate
>> University of Toronto
>> Institute For Biomaterials and Biomedical Engineering
>> Centre For Studies in Molecular Imaging
>>  On 6-Nov-07, at 10:03 AM, John Runions wrote:
>>> Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/ 
>>> cgi-bin/wa?S1=confocal Hello folks,
>>>
>>> Here is one of those seemingly straightforward to answer  
>>> questions that has me really stumped.  You should hear all of the  
>>> BS around here when I bring this up with the other confocal  
>>> 'experts'.  Why isn't there a pinhole in the transmission-image  
>>> forming pathway?  A confocal transmission image would be nice but  
>>> I always tell people it's not possible.  Is it not possible or  
>>> just not done?
>>>
>>> Thanks for your help.  John.
>>> -- 
>>>
>>> *********************************
>>> C. John Runions, Ph.D.
>>> School of Life Sciences
>>> Oxford Brookes University
>>> Oxford, UK
>>> OX3 0BP
>>>
>>> email:  [log in to unmask] <mailto:[log in to unmask]>
>>> phone: +44 (0) 1865 483 964
>>>
>>> web: http://www.brookes.ac.uk/lifesci/runions/HTMLpages/ 
>>> index.html! <http://www.brookes.ac.uk/lifesci/runions/HTMLpages/ 
>>> index.html%21>
>>>
>>>
>>>
>>> New - Oxford Brookes Master's in Bioimaging with Molecular  
>>> Technology <http://www.brookes.ac.uk/studying/courses/ 
>>> postgraduate/2007/bmt>
>>>
>>>
>> Tel: W:416-946-5022