Ed Monberg wrote:
 
>I MUST (as one with product engineering and cost evaluation experience)
 
Where?  In dreamworld?
 
>throw in my measily two cents because I am greatly apalled at the truly
>amazing prices asked (and paid !!) for these quite simple - in concept, at
>least, improvements on the conventional microscope:
>
>Confocal principles are relatively simple and straightforward.
 
True
 
>The components are relatively cheap.
 
Far from the truth.
 
>The only unique parts, as far as I can understand, are software and a small
>part of the optical train.
>
>Therefore, and forgive me for stepping on toes, why must a $10K microscope,
>a $200 laser, a $2500 computer, and a $1000 (generous here) sensor/camera
>add up to such numbers as $250K because of a little label whose name begins
>with N or Z ?
 
I doubt if you could buy one pmt with the required sensitivity for $1,000,
let alone the two or three in a confocal microscope.  An argon-krypton laser
costs in excess of $10,000.  Galvo mirrors capable of scanning at the required
speed seem to only come from one manufacturer (General Scanning, used by
at least 3 confocal makers) and as some manufacturers have found they are
working at the limit of their performance in this application.  The price is
certainly in the thousands. A frame store with adequate performance is also
in the thousands.  At this point we're up to the $30-40 K mark and we
haven't even thought about designing the electronics for signal amplification
and scan control - components which need a pretty high specification
(we must scan a beam of light with ~100nm precision, integrate and amplify
a very weak signal without introducing noise, and so on).  If we are lucky
our eventual annual sale of these might approach 100 units.
 
Now we have to write the software - our users are likely to be fairly
naive so it needs to be as slick and sophisticated as a Microsoft app,
but we will be selling tens of copies per annum - Microsoft sell millions.
 
As for this $10K microscope we're going to mount it on ... that price
would buy you just one confocal water-immersion lens!  If your lenses
aren't at least fluorite your colour correction won't be good enough
for confocal fluorescence to work (the foci of the two wavelengths
won't be close enough to coincident).  And if the lens isn't flat field
the whole exercise has little point!  So we are looking at a minimum of
$2,000 per objective - your complete microscope will have to be at
least $20K - especially since it is pretty hard to use without a
conventional epi-fluorescence system as well.
 
I don't even seem to have mentioned such tricky items as double-dichroic
mirrors, notch filters, etc .....
 
Go back to sleep, Ed, and happy dreams ......
 
 
                                                Guy Cox