How long before LED light is really good?

OK! Don't jump down my throat just yet! I'm not trying to bait anyone here. It's an honest question. But first a few points to give some people an idea of where I'm coming from:

1. Obviously, I would choose a good luxeon based LED light over a mediocre or even moderately good incan. Nothing quite as anoying as that yellowing, poor quality incan light. No question.

2. I do like LED lights. I have a beloved Arc LSH w/twisty that I sometimes EDC, and a FF mk 1, with MM+ adjustable and a Lux III TW0J installed. This latter light has the best beam from any LED light in my (somewhat limited) experience.

3. LED's offer obvious advantages, such as having an incredibly long life and being shock proof.

Now, that said, I must insist that the quality of light from a xenon filled (halogen) incandescent is so obviously superior to LED's--even the best of them--that it still amazes me that I see posts such as "Are incan's dead technology yet?" in the incan forum.

I mean, what do you think surgeons and dentists use for light sources? And check out the testimony of LEO in the thread "Why I still cary incandescents" in the incan forum. In my own line of work here at the particle accelerator, I tried to use my LED lights to light up a survey target, which I view through the optic of a Leica total station. The light simply wasn't good enough to yield the kind of contrast and quality I was used to from a mini-mag with fresh batteries and lamp. But obviously, overall, my FF kicks butt on the mini-mag. Yet the light is not full spectrum light and is simply not adequate for some tasks.

But think of how far LED's have come in the last three years! Awesome improvement! How long, do you think, before the quality of light from LED's starts to rival the light from a good incandescent? I'm guessing three to five years, but does anyone have a more informed estimate? What's on the horizon for LED technology? Will there soon be another high quality/power LED besides the Luxeon? What advances are in sight?

Good one, js. To me, leds need to overcome the following to really take over the joint:
1. Scalability
2. Full spectrum color
3. Heat

Phaserburn,

What's scalability? The ability to be efficient at high as well as low power? Or what?

Scalability: in this context, the ability to go from milliwatt output to 30 watts and more using a single die. JMHO.

in the low power light spectrum LEDs are mostly better than incans IMHO, and they have rapidly improved over the last year. That doesn't mean of course that the color scheme of an incan cannot be superior to a LED, that is simply a matter of planned usage.
The main difference is that incan is strong in the red end of the spectrum whereas LED is strong in the blue end ...
That said, incan light is preferrable for a surgeon's job since the body is more or less in the yellow/red spectrum.

IMHO LED rules in the low end field and will continue its ascent rapidly.
HID is coming in the upper end of power, and incan is trapped in between and will eventually be exterminated /ubbthreads/images/graemlins/grin.gif

But that is not now and not today. Soon ... /ubbthreads/images/graemlins/evilgrin07.gif
When th efirst LED light beats the SF M6 HOLA will can mourn the death of incan lighting ... /ubbthreads/images/graemlins/smile.gif

bernhard

LED lights, within the framework of flashlights, are really good now. In some cases, better beam light distribution quality is needed.

Comparisons of LED light sources with those used by surgeons, dentists, etc. is, in my view, not relevant to much of anything. And, whether they ever find their way into those arenas probably doesn't matter at all.

Advances, obviously will continue, and there will no doubt be some great introductions in the near and mid-term future. However, some of today's LED flashlights are amazing and totally adequate for the majority of applications.

Thus, waiting for more goodness in LED spectral quality is not viewed as productive.

L3

[ QUOTE ]
L3 said:
LED lights, within the framework of flashlights, are really good now. In some cases, better beam quality is needed.

Comparisons of LED light sources with those used by surgeons, dentists, etc. is not relevant to much of anything. And, whether they ever find their way into those arenas probably doesn't matter at all.

Advances, obviously will continue, and there will no doubt be some great introductions in the near and mid-term future. However, some of today's LED flashlights are amazing and totally adequate for the majority of applications.

Thus, waiting for more goodness is not viewed as productive.

L3

[/ QUOTE ]

I'm sorry, but I must cordially disagree. I find in many everyday situations, as well as in the situation I mentioned above (surveying) that the LED light is simply not up to par. Again, please don't get me wrong! I don't have an incan axe to grind. I started out in this whole hobby very pro-LED, but I have been forced to re-evaluate the merits of LED lights from personal experience. In the last two weeks alone, I can recall half a dozen instances where I needed to view some detail or needed light for some task, and I found even my Lux III TW0J @ 750 mA wanting. Your mileage will and obviously does vary, and you are of course free to have any opinion you want, but so am I. And my mileage results for LED's are simply not what I want.

At the very moment I write this, I am investigating a switch over to an incan EDC--probably an E2e. I thinking of switching PRECISELY because I find the LED light wanting even for general useage, even "within the framework of flashlights" now.

They are good, yes, but not good enough, in my opinion. Again, YMMV.

js,

Fellow upstate New Yorker, needless to say your comments are more than welcome, especially since you 'own' this thread. /ubbthreads/images/graemlins/smile.gif

L3

Anyway, this is getting off track!

I didn't want this thread to be an attack on, or a discussion of, or a defense of LED based lights. If you disagree with some of my starting positions, simply disregard them. And instead answer this question:

LED lights, superior as they now are, will obviously get much better over time. How long, how fast, and in what ways will they improve? In what areas will they improve? Where could they stand some improvement? What company or companies will be at the forefront of the advances, and what will they be? Will Luxeons continue to dominate, or isn't there a rumor of some other company that will make a move in this area? Or will we continue to have to suffer with "Future"?

[ QUOTE ]
L3 said:
js,

Fellow upstate New Yorker, needless to say your comments are more than welcome. /ubbthreads/images/graemlins/smile.gif

L3

[/ QUOTE ]

L3, PM sent. /ubbthreads/images/graemlins/smile.gif I appreciate this, BTW. Thanks.

js, are you comparing lights of roughly equal output here?
is it the spectral problem you are facing?
or the beam angle?

because frankly, when I use my stock L4 I find this light more than satisfying and would choose it over the E2e every time ... for close-up and short range tasks, that is.

bernhard

EDIT: typed too slowly. PLease disregard my comments as the starter of this thread wants to keep on topic, what a strange fellow /ubbthreads/images/graemlins/grin.gif. Sorry js.

Bernhard,

The spectral problem only! For example, obviously, at 30-40 lumens my FF w/ Lux III blows away a mini-mag! Yet, I am forced to admit--and all of my co-workers feel the same--that the mini-mag is superior for getting good viewing of the critical surveying cross-hair to target dot operation. There it is. I'm sorry it's the case, I really am, because I am no fan of the mini-mag, but it's simply harder to SEE the position of the cross hairs on the dot with the LED light.

Yes, it's an appealing light, especially at first, and I know that most people think the L4 is far superior to the E2e, but here again we have the full-spectrum, vs. not-so-full spectrum.

Also, I often need light that penetrates and throws farther. I always feel like the LED light is insubstantial and ghostly when I take a walk at night with my FF or Arc.

Or, going back, I remember re-wiring one of the outlets in my appartment, and I found the LED light wanting in that application as well. I found it to be too glaring when I had enough light on the object, but too wispy when pulled out a bit, or angled differently. I like LED lights fine for walking about the house at night or going to the bathroom or taking a shower, but if I'm going for a walk I'd choose a 2 cell SureFire with P60 over either of my LED lights. Granted it's got more output, but I think I'd even prefer an ordinary 2 D cell incan for walking at night.

Just my opinions and experience. No insult intended.

I'd just love to hear someone say "Yeah, in a year or so from now we can expect to see ..."; I'd love to hear some good news for LED's! It'll be GREAT when something the size of a FF puts out 80 lumens of full-spectrum light. Heck, I'd be happy with the SAME output as now, but with full-spectrum.

Maybe my eyes are funny? /ubbthreads/images/graemlins/grin.gif I know I'm in the minority here. Still, I can't deny the way I see things.

Using incan as an example, scalability means you can get more and more light by using more and more power with bigger and badder bulbs. The unit just gets bigger. In effect, bigger=more light. This is what isn't really true of leds.

I am a big LED fan, and since the modified PR reflector made its debut, have been using LEDs exclusively. With that said, I have to AGREE with js regarding the "not-so-full spectrum" aspect of his statement with two qualifiers. The first is ambient light. I find that my PR-T LuxIII 917 as well as my VIP w/BH gets washed out very easily (even at close range) when used where there is a lot of light pollution. Sodium street lamps KILL the LED beam. In this situation, almost any Xenon/Halogen based light will be a better performer IMHO. As light pollution decreases, the more I prefer LED lighting due to overall better color rendition, especially at lower light levels. The second qualifier is the bin of the LED. To me, LEDs on the blue end of the spectrum tend to make darker colored objects look a shade of black. I have stepped on more than one toad during evening jogs (on streets with sodium lamps) because at a quick glance, the brown toad looked more like a black rock. With LEDs tilted toward the yellow/green side of the spectrum, I find this less of a problem.

These are just my observations and opinions from a guy with pretty bad vision to begin with.

I have to TOTALLY agree with js on this too. As far as full spectrum lighting is concerned, it is difficult to find a balance of reds, blues, and greens to simulate "full spectrum" sunlight in ANY light source, let alone LEDs.

LEDs (all white ones in my experience) are defficient in the red spectrum but stronger in the green and blue spectrum when compared to Incandescents. Incands are stronger in the red and some green spectrum but defficient in the blue. Therefore, for wood colors for example, you get the fullness of the browns of the deep grains of the wood with Incandescents. With LEDs, you get a "cooler look" with less reds and more blues and some greens.

Check this out and you'll know what i mean:



Picture 1: Incandescent.


Picture 2: Surefire KL4 (1-cell driven)


Picture 3: LuxeonIII TWOK @750mAh


It took me over an hour correcting the color levels on these lights to closely match what MY EYES see instead of what the camera lens saw. Notice how washed out the LED lights are. But look at how warm the incand is. JS is right...for certain applications, where red hues and fleshtones (like dentists)it would be better to use Incandescents because our brains are more familiar with these colors being so pronounced.

I did an experiment as i was looking for THE BEST compact flourescent spiral bulb to purchase. I DIRECTLY compared 1 Incandecent bulb, 1 5000K Fluorescent, and 1 true full spectrum fluorescent (from fullspectrumsolutions.com)

With the incandecent i'm able to see clearly, my eyes feel comfortable looking around the room...but i get depressed after long periods of time in my room. The 5000K fluorescent looked refreshing at first to see the blues more pronounced in the room. But it was like turning off the red spectrum and it made my eyes STRAIN really HARD after about 20 minnutes. My brain was not use to the strong blues and abscent reds.

The full spectrum lighting was WAAAYY better. The reds were nowhere near the incandscent but they brought them out more than the 5000K. It really does match the sunlight VERY closely. WHen i shut my blinds and open them to saturate my room with sunlight...the difference is almost degligable.

SO back on topic...yes, incandcents are not dead. And if it makes my dentists see my gums better, my surgeon to see my kidney better, and my law enforcement to recognise images better...then incandescents will always be around. Until LEDs can approach full spectrum like the newer full spectrum compact fluorescents...don't count on LEDs to be used in sensitive areas.

P.S.

I remember Lumileds producing "Warm" Luxeon LEDs a few months ago. I haven't heard too much rave about these because most of us prefer the cooler whites of the current LEDs.

If these Luxeons are "warmer" in the reds AND they still posses the strength in the blue spectrum...then we may be getting closer to full spectrum LEDs.

I think it is only a matter of time for manufacturers to start hunkering down on the quality of their phospors in the white LEDs...now that they are become more popular as we speak. I'm sure when Lumileds get a better footing on the general lighting market, the quality will improve making way for fuller light.

Just like fluorescents. They have thrived for a long time producing light matching incandescents, and now they are able to make 5000K light bulbs. But it is only until now that i have been seeing a few manufacturers producing "Full Spectrum" light bulbs for the general light market and use. (they have been around in the agricultural market).

So It isn't impositble...it will just take time in my opinion.

I've yet to find my LED flashlights lacking for general portable lighting applications, but they do seem to suffer from all the streetlight pollution around me. They also seem to be more susceptable to the haze in the air around here - the beam fades as it goes farther and all the crap in the beam obstructs what's being illuminated.

Perhaps I ought get a decent inexpensive xenon light like the Brinkman Legend LX and do some side-by-side comparisons.

I think LEDs might get better spectrum performance by incorporating multiple color die into a single package with some built-in circuitry to balance the output.

There also might be some improvements with the new ZnSe white LEDs - although the initial prototypes Craig reviewed weren't promising.

Mimicing florescent tubes with UV LEDs + UV-sensitive phosphors might be the way to go - if they can get the lifespan of UV LEDs up, deal with the effect of UV on the packaging, and eliminate the UV leakage.

[ QUOTE ]
LEDagent said:
The full spectrum lighting was WAAAYY better. The reds were nowhere near the incandscent but they brought them out more than the 5000K. It really does match the sunlight VERY closely. WHen i shut my blinds and open them to saturate my room with sunlight...the difference is almost degligable.


[/ QUOTE ]
This is exactly what I found comparing different light sources. I prefer sunlight first, then full-spectrum fluorescent. After that my order of preference would be regular 5000K fluorescent followed by LED. While LEDs are fine for small lighting I'm not so sure I would care to light a room with them in their current form. The holy grail in lighting is to produce a light source matching sunlight exactly, and for all intents and purposes full-spectrum fluorescents come quite close. However, for any needs that require very focused beams they are inherent unsuitable, and as loath as I am to admit it, incandescent is the cheapest, most readily available technology suitable for such needs. However, there are drawbacks-even the best incandescents can only run at 3400K, and with very short life. This means they are still deficient in the blue end of the spectrum. And although I'm sure I'll get some disagreement here, as far as I'm concerned with the ready availability and lower total operating costs of full-spectrum fluorescent incandescents have no place at all in general lighting despite their continued popularity.

As an aside, the warm white Luxeons didn't seem to go over too big here largely because their main purpose seems to be to imitate incandescent rather than to be a full-spectrum source imitating sunlight. I think one reason we haven't seen full-spectrum LEDs yet is because they haven't penetrated the general lighting to such an extent that there would be a significant demand for them. Also, with LED makers striving to outdo each other in terms of efficiency and output, adding phosphors emitting more at the red end of the spectrum would be counterproductive (note how the efficiency of WW Luxeons is less than the CW). Color rendering of LEDs is "good enough" for the applications that they're currently used for. Sure, Lumileds could have made a cool version of their white LED with a fuller spectrum, but it would have been far less efficient, and would likely have been used only in niche applications like surgical lighting. BTW, I think 5500K is the agreed upon standard for such surgical lighting, and if I'm not mistaken color-corrected incandescents similar to Solux halogen lamps are what is mostly used.

Im no pro at light talk(in fact when you guys start talking about ma's bin's twoj's etc im totally lost) but this chaps kinda got a point. I find even my xo which is said to have a tight beam for a led when compared to a tight beam from an incan isnt really that tight at all. So obviously there is alot of room for improvement with leds. But on the other hand the thing that sells me on leds is the battery life, which is a really good point of leds. But it will be good when there are really tight throwing leds that are adjustable to flood. If anyone knows how long till this happens it would be interesting. And if anyone knows of any leds that are as tight as incans that would be helpful

Concerning your quote on "what doctors and dentists use".

The days of incandescent lights for surgury and dental material hardening lights are rapidly drawing to a close. There is a company out there that has a battery operated headlamp that is self contained and uses two dimmable Luxeon V (5 watt) LEDs. It is superior to the incan "head lights" with no cord connecting to the light source.
The main bonus is not the portability, clean white light etc... it is the "coldness" of the light. The headlamps that use a bulb are not used because the heat they put off will dry out the tissue. To prevent that, the docs use a fiberoptic cable and those cost $$$$ (a dentist ordered on for a small cost of $4K)

One of the big problems in dentistry has been solved, they used to use ultraviolet devices complete with high wattage (expensive) bulb, cooling fan and filter. Those little guys ran around $3K each! The bulbs are pricey and the glass filter necks are easily damaged. Now, they can pick up a small thing that runs on rechagable batteries pushing current through a Luxeon V in the correct wavelength. Cost? $850

The big surgical lights would be hard to duplicate. Since they can last for 30 years hanging on the ceiling, they will take the longest to convert over. For the big guys it would be a RGB affair. Adjustable Luxeons to make the light accurate, the Red, Green and Blue levels with "preferred tint presets". If those become available, the docs can tint the light the color they want. The cost would be very high but surgical bulbs are not cheap (anything surgical is not cheap)

What would be interesting is "4 watt" LEDs with RGB cores. The only thing I can say is LEDs keep making inroads into incandescents territory, adjustable tint RGB at a decent price would make the trickle into a flood.