Smoother spectrum LED flashlihgts

I see that Warm White LEDs are starting to make progress in the efficiency department.

"Seoul Semiconductor Unveils Warm White Acriche of 42 lm/W"
http://www.marketwire.com/mw/release_html_b1?release_id=241066

Anybody knows of plans for a smoother spectrum flashlight sporting one of those Warm White LEDs?
Surely if people are buying cyan flashlights there should be market for balanced spectrum ones.

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On another note I tried a Streamlight Twin Task 3xAA a guy has at work.
I wired both the LEDs and the incandescent bulb together. With a piece of "satin" tape in front as diffuser, it had relatively smooth beam and consistent spectrum (all electrical wire colors in the lab looked natural). The current was about 850mA on half spent alkaline batteries though. That is a bit too high load for a AA battery (measured 1.4V after the experiment). It may be better with les blue LEDs and lower current bulb...

There is nothing particularly "balanced" about the colors of the Seoul Warm White. They are just a different color of white, but not a particularly good quality one.

I would far prefer the 4K color temps with high efficiency.

Semiman

For now the only LED that I know that is actually using a neutral color temperature (4100K) is the Luxeon Rebel Neutral White, and those aren't shipping yet. Everything else is either a cool white (6000K or so) or an attempt to mimic incandescent (3000K).

However, just about any single-phosphor LED will be relatively weak in red color rendering. "White" in most current LEDs is generated by producing blue, then converting part of that to a yellow-green color with a phosphor. The spectrum is actually fairly broad/smooth, but it's deficient in the red, similar to the old cool white fluorescent tubes. Modern fluorescent tubes however use three phosphors -- separate red, green, blue, and output sharp "spikes" rather than a smooth spectrum, but actually perform much better in terms of real-world color rendering, so continuous spectrum isn't everything. Using a two-phosphor mix (separate green and red) at a 4000K color temp would improve things dramatically.

Eventually I think a lot more LEDs will emit white as a combination of separate red, green, and blue emitters. I believe Cree actually has a patent involving the emitters actually stacked on top of each other, instead of side by side, which will allow for consistent color mixing. The only thing I think holding RGB white is that the green emitters are particularly inefficient -- only about 5-10% compared to around 30-50% for red and blue. That's why it's currently more efficient to make green by converting it from blue using a phosphor. (Our eyes perceive green the brightest, so that's why cool white LEDs are brighter than the blue LEDs they're based on.)

The advantage of an RGB LED though is that it would allow the user to change the apparent color temperature/white balance in real time: ie use a warm white in the fog, a more neutral white indoors, a cool white for doing something like sorting dark blue socks. There's also the possibility to emit only the red component to preserve night vision.