When will we see high powered LED's?

I think LED lights are pretty cool, and I have a few (L4, T3, T4), but they are nowhere near my SF M3 with MN11 when it comes to output. That thing is just scary bright. While LED's are superior to incan's in every other way, they just can't compete with my M3 or 10X, not even close. So when, if ever, will we see something with output around at least 200 lumens in a similarly sized light?

Thanks

The real limit on LED lumens is thermal dissipation. LEDs require conduction through a heatsink to remove excess heat, while incandescent filaments are able to radiate away most of their heat through the beam itself. When LEDs become more efficient, or when they are able to tolerate hotter temperatures, higher outputs will be possible. The upcoming K2 from Lumileds will be the next big step in output.

There is also the important issue of focusing. Many stock LED flashlights, including good ones like the Surefire L4, can't focus their beams as tightly as the typical incandescent flashlight. This weakness can be lessened by going to a larger reflector, although you then lose the advantage of having a very small flashlight. A 1-watt Luxeon centered in a standard Mag C or D reflector will produce an intense beam that will make the L4 or even the T3 look like a joke--even though the L4 and T3 put out more total light. The new Dorcy Luxeon 3D, which is sold at Target and not very expensive, is supposed to have this kind of beam.

Scaling is the big issue with LEDs. All the waste heat needs to be conducted away and radiated or exchanged away somehow... unlike and incandescent filament that radiates nearly 100% of its waste heat directly as infrared radiation.

There have been a few experiemnts with 10W and 20W LEDs ... from what I've been able to gather, they aren't really practical enough for commercialization.

You can realize huge outputs from LEDs if you use parallelism - I've seen a number of maglite mods using 3 to 4 Luxeon 3s; driven moderately, you'll probably see 200-250 lm from the 3x light, and 260-330 lm from the 4x light. Of course, you'll miss the throw from a single reflector...

The advantage for LEDs will continue to be in lower-power devices. While not as simple as incans, they do beat out technologies like HID, etc which require high starting/operating voltges and don't work as well at low wattages; LEDs are low-voltage DC current devices using much simpler electronics (as simple as a resistor) for operation & regulation. LEDs are also very efficient at low voltages/watages compared to most other lighting technologies.

There are some advances coming down the pipeline for LEDs:

• Yellow phosphors keep getting better - more blue is converted to yellow & red for greater efficiency.
• Nano-cavities in LED die can up die efficiency by up to 400%.
• UV die + white phosphor promises to be more pomising that blue die + yellow phosphor with much fuller spectrum, consistent binning, and potentially greater efficiency

The above bullets really point to greater optical efficiency... More (electrically) efficient die could alleviate the inescapable heat isssue - power could go up to compete with those big incandescents & HID.

Incandescents will be around for a while due to their wide operating ranges (fractional-watt to hundreds of watts), simplicity, ease of manufacture, and their short lives is incentive to keep making them (nothing like a steady cashflow). Supplied with the proper voltage, an incandescent filament has an amazing ability to regulate its own current consumption... so long as the voltage source is correct, no other electronics are typically needed.

idleprocess said:

• Nano-cavities in LED die can up die efficiency by up to 400%.

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As reported in Science, the efficiency increased by 15x in one study. To quote the article:

the emission efficiency for the direction normal to the crystal (Fig.
2B) increases by more than a factor of 15 within the [region with holes] . . .

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Of course you still have to be able to manufacture it and get it to do that with a standard DC power supply.

See Science Magazine in the research reports section, "Simultaneous Inhibition and Redistribution of Spontaneous Light Emission in Photonic Crystals" by Fujita et al, 27 May 2005, page 1297; www.sciencemag.org .

Scott

Aaron said:

LED lights...are nowhere near my SF M3 with MN11 when it comes to output...

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You can buy an LED light TODAY with more overall output, greater runtime, AND lower cost than an M3 with MN11: the Elektrolumens Tesla-6:

http://elektrolumens.com/Tesla-6/Tesla-6.html

The M3/MN11 produced 150 output units on Flashlightreviews.com's test, equal to about 215 lumens.

The Elektrolumens Tesla-6 supposedly produces 432 lumens, although it hasn't been tested by Flashligthreviews.com.

True the Tesla-6 uses multiple emitters, but this is an implementation detail separate from the final cost or ultimate performance of the overall product.

The Lumileds K2 emitter is already shipping in sample quantities, and will produce 60 lumens/watt. Max output might be 150 lumens; we don't know for sure. Assuming 150 lumens a Tesla-6 using K2s could theoretically produce about 900 total lumens.