Can anybody recommend a high power white light source?

I would use a trio of red, green, and blue LEDs to make the desired color temperature instead of white LEDs. You can add more LEDs to get the luminosity you need or go with higher power LEDs (which are available). I worked for a company that used LEDs for exterior aircraft lighting, so you can have all the luminosity you want from LEDs. Automakers are starting to use them for headlights!

Also, you can pulse width modulate each color LED to fine tune the color temperature to whatever you want and all at a lower power than any other lamp technology.

Thanks! This is a very interesting idea, to mix light at the preferred ratio. I am a bit concered of how well i would be able to control the light output though...

You can modulate the DC current in the Xenon bulb. I've done it with a simple PWM circuit. I don't know what running a Xenon bulb at lower than rated wattage does to the color, though - it looks the same to my uncalibrated eyes.

I did a recent project involving white LEDs - about 100 of them run together. That made light so bright you couldn't look at, or near it. It also used a simple PWM controller to adjust the brightness.

You can modulate the DC current in the Xenon bulb. I've done it with a simple PWM circuit. I don't know what running a Xenon bulb at lower than rated wattage does to the color, though - it looks the same to my uncalibrated eyes.

That's something maybe we can do..., did you built the PWM circuit yourself?

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I did a recent project involving white LEDs - about 100 of them run together. That made light so bright you couldn't look at, or near it. It also used a simple PWM controller to adjust the brightness.

Could you tell me where did you get the 100 LED light? The ones i can find from EdmundOptics, Thorlabs, etc., generally contain 20-30 LEDs. Also, where did you get the LED driver for it? Thanks a lot!

I built the PWM controller for the Xenon bulb - it's a relatively simple - one chip, one MOSFET circuit. A colleague designed the LED controller - again a simple one chip, one MOSFET circuit. We had a PCB built to hold the 100 LEDs.

Google "LED lighting" and you will find lots of off the shelf items.

Very helpful information, thanks!

Hello williamy,

You can purchase very high intensity LEDs (and drivers) from Luxeon, Cree, and others. Roithner-Laser's LED arrays cost an arm and a leg (and possibly your firstborn), but they provide a truly intense source of white light, if that's what you need and are willing to pay the price. All can be modulated at 50 Hz rates and higher.

Thank you, europium. I looked through some LEDs from these companies. It looks like the max output from these LEDs is 120lm, at wide view angle. This is kinda small compare to what a Xenon lamp can produce...

Or, i am in trouble of comparing the beam output in lumen, mW, candelas, and J/flash!

"High power" is a relative term, of course, and I was remiss in asking the OP what high power means in this application. Are you the OP, or someone else?

At any rate, xenon flashlamps can be strobed at rates of 50 Hz and much higher. The spectrum of a xenon lamp peaks in the green and violet, whereas white LEDs can be tailored to provide a broader spectrum leaning toward the blue ("cool white") or the yellow ("warm white"). The spectrum of a xenon lamp does not vary with the rep rate, but with the specific gas mixture.

But what is unknown here is what is meant by "high power." If you're the OP (posting as Guest) can you specify this value in technical terms? It might help to shed some light on your specific requirements.

"high power" is what i put here, as for example, a commonly used 300W Xenon lamp opertaing at DC current can give 5000lumen optical power. I am looking for a strobed Xenon lamp which can give samiliar output---i am not sure how to put the unit here, J/flash? lm/flash?

it's good to know that the spectrum of a xenon lamp does not vary with the rep rate, but with the specific gas mixture.

A Joule is a watt-second. A 300 W xenon lamp running for one second uses 300 Joules of energy (how much of this energy is actually converted into useful light is another matter. I don't know the typical efficiencies of these lamps and I'm presently too busy to look them up). But, if you need to know how many Joules per flash, and the intensity of your 300 W xenon lamp fits the bill, then you can compute (roughly) how many Joules you will need to deliver per flash (of equivalent brightness) by multiplying the flash duration (typically microseconds to a few milliseconds) by 300 W.

Say your flash duration is 1 millisecond (1e-3 sec), then you will need to deliver 0.3 Joules per flash to get the brightness equivalent (during the flash interval only, of course) to your 300 W bulb. Multiply that figure by the rep rate to calculate how much energy you're delivering per second, if you need to know that. If your rep rate is 50 Hz, then your flashlamp will deliver 50 x 0.3 J = 15 J per second. As the eye tends to integrate rep rates above 30 Hz or so (the so-called 'fusion frequency'), your flashlamp will appear to be, on average, much dimmer than the 300 W beastie running continuously, but each flash will be just as bright.

On the other hand, if your flashlamp has to deliver 300 Joules per second to appear as bright as a continuously-running 300 W xenon bulb, you will have to deliver that much energy - 300 W - in 50 flashes (per second) of one millisecond each, so each flash will need to deliver 300/50 = 6 Joules per flash.

Thank you, Europium. Your information is really helpful!

You are right about the converting efficiency of the 300W lamp. This is something i definitely need to check out.

Right now I am just randomly searching for different white light source, either white LED or Lamp, to find out the right illumination for our tissue imaging system. Things we care are the power, uniform spectrum in VIS, and be able to be modulated. It seems a simple task, but turned out quite overwhelming to me, since i am new to "illumination".

Given the spectrum uniformity and color temperature, i tend to find a Xenon flash lamp. White LEDs are emerging, but the total output seems low compare to what lamp can produce. White LEDs i found so far generally give 100lm, while Xenon lamps can give 5000lumen (but again, I am not sure what level of power we will actually need). Also, the spike in white LEDs' spectrum is a concern to me as well. Do you have any commend on that?

One college just gave me a Xe flash lamp(up to 60Hz max modulation) with has 0.6J/flash output. He said that it has been used for similar white light imaging before, and the light was enough. So this is some number i can use as reference. But i do not have the data sheet for numbers such as the rep. frequency, flash duration, etc...

See here: www.elecosn.com

Here are dimmable LED Bulb, and LED incandescent bulb

dude:

SOME OF THE NEW T5 AND T8 FLUORESCENTS TUBES RUN ON ELECTRONIC BALLAST AND YOU CAN FIND SPECIALITY T8'S THAT RUN 5000K OR MORE. NOT SURE ABOUT THE REST OF YOUR REQUIREMENTS, BUT MOST T8'S ARE DIMMABLE WITH THE RIGHT BALLAST. jUST SOME INFO-NOT SURE IT WILL HELP.

Thanks for the info!

We use halogen light units for testing, these have a 100W halogen lamp but this is focused into a flexible fibre optic bundle to give a concentrated intense output. The output can be filtered to block wavelengths that are not wanted & the unit incorporates a dimmer.

I would start with Dolan-Jenner, I have used their products before and been very satisfied.

Mike

Advanced Microscopy Group(www.advancedmicroscope.com) has a gooseneck LED source, 6200K, right at 520nm's, is modulated, is also AC. Buy it off the shelf. More LED light than most people will ever need.

Thank you. I looked up their website, but couldn't find any product info there:(

Here's a link to their illuminator datasheet. I don't see on the sheet that the light is modulated, nor how. The only frequency spec on the datasheet refers to the 50/60 Hz AC line frequency.

PHILIPS CDM - 4200 k

The CDM philips technology can be suitable which is PCA (Poly Crystaline Alumina ) discharge tube technology.

The rare earth metal iodide technology as used inmetal helide lamps, offering white light with a high efficacy. in this technology a mix of different metals, like sodium , thallium, dysprosium, Thulim and Holmium, chemically bound iodide is used togather with some mercury. These metals when in a vapour phase contribute to the diferant part of the sprectrum: e.g Sodium with red, Thallium with green etc.

The combination of these two technologies resulted in a highly efficient white light source with excelent colour stability and long life. The technical terms of this product range is : CDM ( Ceramic Discharge Metal Helide)

ceramic technology allows for higher operating temperatures. The number of light generating mtaalic ions in the arc can therefore be increased leading to a better - filed distribution resulting in excellent colour rendering.

nascon

You might want to look into white-light ion lasers. They're produced by Coherent and Spectra Physics/Newport

You might look at dental curing lights used for white tooth filings. They seem to use very intense-hand held white lights. Look in dental supply catalogs.

Just an idea.

There are a number of companies that make xenon light sources that are used for endoscopic use. Basically, they're xenon arc lights that run off a power supply that uses AC power. Try sniffing around Newport Corp.