using Led in place of halogen bulb in Fiber Optic Light Sources?

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
Post Reply
Message
Author
Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

using Led in place of halogen bulb in Fiber Optic Light Sources?

#1 Post by Milou » Mon Jan 03, 2022 12:44 pm

Has anybody already substituted halogen lamp in a Schott Fiber Optic Light Source, like a KL1500, or even in similar other kinds of Fiber Optic Light Source?

Is it necessary to also modify this kind of power system, as GY6.35 Led have a much lower amperage (generally under 10W) comparing with about 150W halogen bulbs!

If anybody has already done this job and could give a way to proceed.....
Thank you

Hobbyst46
Posts: 4277
Joined: Mon Aug 21, 2017 9:02 pm

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#2 Post by Hobbyst46 » Mon Jan 03, 2022 1:29 pm

Milou wrote:
Mon Jan 03, 2022 12:44 pm
Has anybody already substituted halogen lamp in a Schott Fiber Optic Light Source, like a KL1500, or even in similar other kinds of Fiber Optic Light Source?

Is it necessary to also modify this kind of power system, as GY6.35 Led have a much lower amperage (generally under 10W) comparing with about 150W halogen bulbs!

If anybody has already done this job and could give a way to proceed.....
Thank you
Never done it but I would question it if is worth the cost and labor. Unless the ambition is a monochromatic LED light source.
LEDs utilize a significantly different electrical circuit from that of halogen. One needs a constant current DC power supply and DC. Different mechanical connection and different heat sink.
A fiber optic light source gains from the positive properties of the halogen light, and does not heat the optical parts or specimen.
A halogen bulb that is driven by its optimum voltage (slightly below maximum) can serve well and long-term.
The only obvious disadvantage of the halogen is power consumption. Unless the microscope is being used around the clock, that seems to me relatively unimportant.

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#3 Post by MichaelG. » Mon Jan 03, 2022 2:51 pm

I have been pondering this general idea for a while now ... but have so far found no convenient practical solution.

Although the electrical modifications may be tedious, they are not difficult : The main problem is the optics !

The light input to the Fiber is best configured as a converging cone, BUT the light output from most LEDs is divergent.
... and, to make matters worse, most of the high power white LEDs are large area [being an array of small diodes immersed in a common matrix]

By contrast, the typical tungsten "Fiber Optic" lamp has an omnidirectionally radiating filament positioned in a parabolic reflector ... cunningly producing the requisite converging cone of light. See diagram here: https://www.stagelightingstore.com/lamp ... ber-optics

If you search for something like 'ball lens fiber optic coupling' you should find ray diagrams which may help.

I'm sure it's not impossible to do a conversion; but it will be trickier than you might think.

Please do keep us informed of your progress.

MichaelG.
Too many 'projects'

BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#4 Post by BramHuntingNematodes » Mon Jan 03, 2022 3:44 pm

There are quite a few low cost parabolic reflectors designed for LEDs that usually point the light forward. One of these in combination with a convex lens might do the trick
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#5 Post by BramHuntingNematodes » Mon Jan 03, 2022 3:49 pm

Also one advantage of an led is the possibility of using passive cooling as I have found the fan on these can introduce vibrations
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination


Phill Brown
Posts: 603
Joined: Mon May 24, 2021 1:19 pm
Location: Devon UK.

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#7 Post by Phill Brown » Mon Jan 03, 2022 5:58 pm

LED torch might have the main components to work with, LED,reflector, heatsink, regulator.
DC PSU substituted for the battery pack.
Might not be optimal but sounds doable with low voltage.

PeteM
Posts: 2983
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#8 Post by PeteM » Mon Jan 03, 2022 9:40 pm

Why?

Unless the slight noise of a fan is a bother (affix it under the table?), I'd be inclined to use a tungsten halogen fiber optic light source as is.

It will likely (1) be brighter than most LED sources; (2) have a higher CRI than most LED sources: and (3) won't have significant problems of heat, given that the bulb is an arm's length away. Between filters and white light balance settings, and the broad spectrum available, it's easy enough to get whatever quality of light you might want.

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#9 Post by Milou » Tue Jan 04, 2022 12:06 pm

Thank you for your comments and ideas

Why would I replace halogen with LED?
In fact , I'm just curious to know a possible modification of my equipment, but I still presently I use halogen Fiber optic light :-)

But ideas about reflectors designed for LEDs and/or LED torch could also be an alternative or a complement!

@Saul
Very interesting your work with LEDs in different setups. Thanks to present your tests

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: using Led in place of halogen bulb in Fiber Optic Light Sources?

#10 Post by MichaelG. » Wed Jan 26, 2022 3:51 pm

.

I am just reviving this topic to reference the recent contribution by Enrico Savazzi, here:
viewtopic.php?f=28&t=14740

MichaelG.
Too many 'projects'

Post Reply