Commercial Response
We have followed this discussion thread with interest. We can confirm that CoolLED provides spectral data on its website and we endeavour to respond quickly when more detailed information is requested.
Excitation filters are required as LEDs do emit a significant tail off the peak that would show up as background when it crosses the emission filter passband. The level of blocking required when using LEDs is much less than when using an Hg bulb so there is no need for an OD=6 outside of the excitation passband. This should reduce the demands on filtering as LEDs become more common in fluorescence.
We fully understand the complexities involved when measuring intensity at the sample. I have personally been shocked at how much results can vary depending on the measuring kit, microscope set-up and techniques used. This may explain why some product manufacturers claim extreme intensity results that don’t hold up when side-by-side comparisons are made. CoolLED can provide product on evaluation so that the user can be satisfied that performance will be achieved in their application.
CoolLED would also be happy to provide its LED product to any impartial individual or institution interested in doing a comparison of sources. We are happy to share our knowledge on measuring intensity based on many years of experience in LED illumination in microscopy.
Best Regards,
Gerry
Gerard Whoriskey
Development Engineer
Email: [log in to unmask]
Tel: +44 (0)1264 323040
Fax: +44 (0)1264 723897
Mobile: +44 (0)7789535762
-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Vazquez Lopez, Julio
Sent: 28 February 2012 01:01
To: [log in to unmask]
Subject: Re: LEDs
*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****
And with regard to Lumencor and similar light engines, a description of the system can be found here:
http://www.lumencor.com/docs/Lumencor%20White%20Paper.pdf
and more detailed information of what's inside can be found in Lumencor's various patents, such as this one:
http://www.patentgenius.com/patent/8098375.html
Julio.
==
----- Original Message -----
From: "Craig Brideau" <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, February 27, 2012 4:14:08 PM
Subject: Re: LEDs
*****
To join, leave or search the confocal microscopy listserv, go to:
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*****
Yeah, the part where it sort-of has a bulb threw me for a loop. So it seems like it is a bulb without filaments; just a gas pocket inside a dielectric. It will be interesting to learn what the 'field' lifetime of the bulbs actually end up being.
Craig
On Sun, Feb 26, 2012 at 6:30 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
> *****
>
> If you follow the links from that Thorlab website you gave, you find:
>
> "the heart of LIFI(r) is the bulb sub-assembly where a sealed bulb is
> embedded in a dielectric material. This design is more reliable than
> conventional light sources that insert degradable electrodes into the bulb.
> The dielectric material serves two purposes: first as a waveguide for
> the RF energy transmitted by the RF Power Amplifier Circuit (PA) and
> second as an electric field concentrator that focuses energy in the
> bulb. The energy from the electric field rapidly heats the material in
> the bulb to a plasma state that emits light of high intensity and full spectrum."
>
> In other words, it's not solid-state at all. But it's a very neat idea.
> Note that they don't tell you what's in the bulb!
>
>
> Guy
>
> -----Original Message-----
> From: Confocal Microscopy List
> [mailto:[log in to unmask]]
> On Behalf Of Craig Brideau
> Sent: Monday, 27 February 2012 12:11 PM
> To: [log in to unmask]
> Subject: Re: LEDs
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Some of these 'solid state' light sources claim to be plasma based?
> What are these things, and does anyone care to share their experiences
> with them? Here's a link to the kind of source I'm talking about:
>
> http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=5551
>
> I don't have any experience with these and was curious.
>
> Craig
>
>
> On Sun, Feb 26, 2012 at 10:38 AM, Christian Mohn <
> [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
> > *****
> >
> > Hi,
> >
> > we are just about to go thru the same procedure. Some things became
> > obvious while unravelling the marketing pdfs.
> > 1. nobody tells you where and how they measure output or what the
> > illuminated field of view is... 45mW on a 11mm f.o.v is different
> > from
> > 45 mW on a 25mm field of view (I assume the direct coupled will all
> > fill the 25 while a 0.3NA fibre only fills F.oV of 16mm reasonably) 2.
> > solid-state is just another word for "yes, for some we use a
> > phosphor in front the led chip" and this will definatly not increase
> > overall power since phosphorescence will never reach 100% efficiency....
> >
> > My advice... get a device to your lab and test it.
> >
> > Best wishes from the cold north,
> >
> > Chris
> >
>
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