http://confocal-microscopy-list.275.s1.nabble.com/Brightness-difference-Hg-vs-LED-tp7581211p7581309.html
long-wavelength output from Sutter. At 740 nm we get about 50 mW out of
a 10x objective in a 13 nm bandwidth. I don't know if that qualifies as
powerful or not, but for epi-fluorescence imaging, it's pretty bright.
> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> *****
>
> Hi All
>
> This posting of a couple of weeks ago has suddenly become relevant for us.
>
> Does anyone know of a powerful continuous white light source in the 600-800nm range? Emphasis on the word 'powerful' because in most light sources there seems to be a steep drop in power above 650nm.
>
> Thank you,
> Judy
>
> Judy Trogadis
> Bio-Imaging Coordinator
> Keenan Research Centre, St. Michael's
> 209 Victoria Street
> Toronto M5B 1T8, Canada
> office: 416-864-6060 ext. 77612
> imaging facility: ext. 77434
> cell: 416-254-9330
>
[hidden email]
>
>
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:
[hidden email]] On Behalf Of Ben Freiberg
> Sent: Thursday, November 07, 2013 10:59 PM
> To:
[hidden email]
> Subject: Re: Brightness difference Hg vs LED
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> *****
>
> All,
>
> Having been involved in the lighting industry from a commercial standpoint I
> wanted to respond to this thread in an unbiased and independent experienced
> voice.
>
> As has been previously mentioned, there are many areas of the spectrum in
> which solid-state solutions have surpassed HBO in intensity at the sample
> plane. I completely agree with the assessments that there are many
> components that go into building an illuminator and therefore many sources
> of light loss in the systems on the market. Key to any measurement of power
> is how much light is delivered to the sample, so if anyone does take up the
> offer to compare light sources, measurement of mW//cm^2 at the sample plane
> will provide the best indication of the total performance of a light source
> on a microscope. That being said, one must make sure that the excitation
> filters used with solid-state sources are matched to the peak of the source
> and not simply use off the shelf filters and expect them to perform optimally.
>
> There has been mention in this thread of the gaps produced when using
> multiple sources and combining them into a shared collimated beam. As has
> been stated, in general, increasing the number of input sources decreases
> the overall throughput of light in the system as source combining optics can
> be lossy and will cut the overall intensity of any single source that could
> be coupled to the microscope. One solution that has not been mentioned in
> this thread is the 120-LED from Lumen Dynamics. The 120 LED overcomes the
> limits of combining multiple sources by using a high intensity white LED
> source. This product, according to the LDGI website, covers wavelengths
> from 370nm all the way out to 700+ nm with reasonable intensity. While HBO
> may be brighter at some wavelengths versus the 120-LED, rarely are these
> sources, HBO or solid-state, used at max power especially in live cell
> applications.
>
> I would suggest that the 120-LED be included in whatever tests come from
> this thread as it is a unique product from the standpoint of how the white
> light is generated for fluorescence applications versus the other solutions
> on the market that combine many sources.
>
> As for the overall performance of all solid state products mentioned thus
> far in this thread, one should consider the following: every mid to high end
> solid state source produces multiple times more power than 175W xenon at the
> sample plane at all wavelengths greater than 360nm and all the way out to
> the NIR. If anyone has experience using xenon as their primary source, I
> hope this puts the current state of solid-state illuminator intensity into
> perspective. Bottom line is for most applications, the benefits in cost of
> ownership, stability and overall function have the solid-state solutions
> greatly out-perform their HBO counterparts with an additional benefit being
> that solid-state sources are a green solution and they eliminate the threat
> of mercury contamination due to improper disposal or explosion of mercury
> burners.
>
> Ben
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Tue, 5 Nov 2013 12:56:42 -0500, Philip Oshel <
[hidden email]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>> *****
>>
>> All,
>>
>> I had this question put to me by a new faculty member, and don't have a
>> ready answer:
>> "Is there a ballpark percentage for how much less bright an LED vs a
>> standard mercury lamp light?"
>> This is for regular epifluorescence, not confocal.
>>
>> This is in the realm of arm-waving over a picture of beer (a good, dark
>> stout), ignoring brands, how old the Hg bulb is, ex/em cubes, which part
>> of the spectrum is used, and all that. Personally, I'd think the answer
>> is more like, "Doesn't matter, the dimmer system is still too bright to
>> use all the available light and not damage the specimen." But ... ?
>>
>> Phil
>> --
>> Philip Oshel
>> Microscopy Facility Supervisor
>> Biology Department
>> 024C Brooks Hall
>> Central Michigan University
>> Mt. Pleasant, MI 48859
>> (989) 774-3576
>