What's the latest on the higher powered LEDs?

What\'s the latest on the higher powered LEDs?

hey guys, has anyone heard anything new lately on those 2W/5W luxeons or the super-nichia equivalents? like confirmed shipping dates, colors offered and prices, for instance?

or for that matter - anything new on the regular LED horizon - like a 8000mcd nichia white or something? things do seem to be getting a little quiet around here...

Re: What\'s the latest on the higher powered LEDs?

I agree, very quiet. Someone out there, give us some hope!

Re: What\'s the latest on the higher powered LEDs?

Have you seen these?







Here--> http://www.optotech.com/

Re: What\'s the latest on the higher powered LEDs?



Thanks, Fahaka

Hey, yeah! - I've been to their site a coupla months back, but I didn't realize they make *WHITE*! I *do* know that these guys get really hot too and they're referred to a ultra-high power LEDs. Has anyone seen their use in a flashlight yet?

Re: What\'s the latest on the higher powered LEDs?

As far as I'm aware, these are multijunction devices with a Vf in the 10-15 volt range.
I'd have to dig through and download spec sheets to get an exact figure.

Re: What\'s the latest on the higher powered LEDs?

I saw the website a couple of months ago and got really interested until I saw the data sheets.

Those T0-66 modules may be small and bright but they are about half as efficieny as 5mm Nichia whites.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>- anything new on the regular LED horizon - like a 8000mcd nichia white or something? <HR></BLOCKQUOTE>
I don't know about anything new but the S-rank 8000mcd Nichia white has been out for quite a while. Its the mysterious T-rank LED that I want to know about!

Re: What\'s the latest on the higher powered LEDs?

stupid question, what are the units of dimension on thier data sheet, mm, cm, or inches?

Ake

Re: What\'s the latest on the higher powered LEDs?

Here is some info I have on the larger 5w Luxeons
http://www.uwgb.edu/nevermab/led/luxeoncar.pdf

and
http://www.uwgb.edu/nevermab/led/luxeon5w.pdf


I am told this is now public info, so there you have it.

Re: What\'s the latest on the higher powered LEDs?



Thanks, Brock! You've effectively ended my drought!

Re: What\'s the latest on the higher powered LEDs?

whooooaahhh.... it's just hit me..... *maybe* - just maybe, Peter was really holding out on the ArcLS because of *these* puppies!! I'm feeling kinda dizzy now at the thought of a 5W luxeon in a 2CR123 pack for the ArcLS! FIVE WATTS!! That blows my PT40 clean out of the water! Dunno about an E2, but I'd be surprised if 5W of white LED light in your face wasn't considered a tactical advantage! Man, no need to overdrive this baby...

Re: What\'s the latest on the higher powered LEDs?

gransee has ordered 5 watts he said so

Re: What\'s the latest on the higher powered LEDs?

Yeah, Peter, and a few others

As reported earlier, one company that I know of has completely skipped the 1W Luxeon, and has been working with the 5 Watt since January.

I am keeping my fingers crossed that I will have their proto-type by July 1

Re: What\'s the latest on the higher powered LEDs?

Nows thats cool. From the datasheet it seems like the efficiency has increased from a paltry 15 lm/W for the orignal Luxeon to 25 lm/W!!

Only problem is the juction voltage has doubled to 6.84v, so unless you're using a regulator or a DC-DC converter, you're gonna need more than 2 CR123s or at least 5(!) normal alkalines.

Re: What\'s the latest on the higher powered LEDs?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Someguy:
Only problem is the juction voltage has doubled to 6.84v, so unless you're using a regulator or a DC-DC converter, you're gonna need more than 2 CR123s or at least 5(!) normal alkalines.<HR></BLOCKQUOTE>

That's exactly what an ArcLS has - remember, an LS is really not supposed to light up on just one 1.5V/1.2V AA =D

2xCR123As = 6V, not that difficult to bump up to 6.84 (easier i'd think than 1.5v to 3.6v) and gransee *did* say his electronics were rated up to 6V on the input stage.

Things are beginning to add up here...

Re: What\'s the latest on the higher powered LEDs?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Someguy:
Nows thats cool. From the datasheet it seems like the efficiency has increased from a paltry 15 lm/W for the orignal Luxeon to 25 lm/W!!
<HR></BLOCKQUOTE>

Cool is right. In fact, cool is the problem. You get 25 lm/W if the junction temperature is maintained at 25C. With a rather good heatsink, running at full power in a 25C environment, you will hit the maximum junction temperature of 125C, and you will be down at 18 lm/W. With a _perfect_ heat sink, the junction to case thermal resistance would still have the junction at about 80C at full power.

-Jon

Re: What\'s the latest on the higher powered LEDs?

Bring on the liquid Nitrogen injection!

Re: What\'s the latest on the higher powered LEDs?

Guess that would mean we'll be seeing finned heads a la Surefire! The 5W luxeon specs do indicate that heatsinking is a MUST even for 'extremely short' durations when driven to spec. Well, those who complained that LEDs don't warm their hands in the cold won't have anything to gripe about now!

I'd wonder though, how these 5W would perform if slightly *under*driven. Hoping for less heat and even 2-2.5W of light would be plenty. 5W could be had for short bursts.
Anyways, I'm sure it'd be lots cooler than an equivalent Surefire after 15 minutes of continuous max burn-time, so if you knew how to handle of those, a 5W luxeon should be manageable.

Re: What\'s the latest on the higher powered LEDs?

Unfortunately, LED's can't handle as much heat as halogens, so a comparision to a surefire isn't quite valid. I certainly hope that an underdriven 5w LS doesn't get too hot, as I'd really like to fit them into a truly waterproof light, like a UK SL4 or tec 40, but of course that means plastic. Has anyone actually tried one of the current LS's in a small plastic flashlight?

On the plus side, if the new LS's create more visible light per watt, they should also create less heat per watt than the older LS.

Re: What\'s the latest on the higher powered LEDs?

Now bringing this topic to our next great hope - Organic LEDs! Anyone heard of any development in this area for flashlights or other portable general illumination? White is supposed to be intrinsically possible with OLEDs, so the efficiencies are far improved over current phosphor-doped white LEDs.

Craig also mentioned something about newer formulation LEDS (the normal ones we're used to, that is) being able to natively generate white light. Any other info here, like their output ratings and comparative efficiencies against other monochromatic LEDs?

Re: What\'s the latest on the higher powered LEDs?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by hotfoot:
Now bringing this topic to our next great hope - Organic LEDs!
White is supposed to be intrinsically possible with OLEDs, so the efficiencies are far improved over current phosphor-doped white LEDs.
<HR></BLOCKQUOTE>

The basic principle of polymers that emit light (OLEDS) can be explained as follows. A thin-film semiconducting polymer is sandwiched between two electrodes. Electrons and holes are injected from the electrodes and recombination of these charge carriers leads to luminescence. The bandgap, the energy difference between valence band and conduction band of the semiconducting polymer, determines the wavelength (color) of the emitted light. Sooo, the physics of operation is similar to "normal" monochromatic LEDS, but OLEDS are simpler and cheaper to make. Thus they can be made large. One can't economically make an 8x10 inch GaN LED!!! They probably can make a white OLED, but it would involve phosphors just like a white LED, or mixing red, green, and blue OLEDS in a sigle device. A state of the art OLED has two different polymer layers (one for injecting electrons and one for injecting holes). The light is produced where these electrons and holes recombine (sort of annihilate each other). The energy of the recombination determines the color of the light - which is pretty closely monochromatic. They can cause the recombination to take place in or near a phosphor layer to make a different light color.

As far as efficiencies, efficacies approaching 10 lm/W have been achieved for some laboratory OLEDS in certain colors. Nichia whites are 15-20 lm/W and you can get some green LEDs as high as 50+ lm/W. So OLEDs have a way to go for efficiency.

The big stumbling block for OLEDs is limited lifetime. Right now they are not as good as standard LEDs, but I'm sure they are working on it. I heard they are up to 30,000 hours lifetime in some LAB OLEDs.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>

Craig also mentioned something about newer formulation LEDS (the normal ones we're used to, that is) being able to natively generate white light. Any other info here, like their output ratings and comparative efficiencies against other monochromatic LEDs?
<HR></BLOCKQUOTE>

I defer to Craig if he has new info on this, but the mechanism used to generate light in normal LEDs would would not support producing white light from a single semiconductor chip with no phosphor coating. I've heard of white light LASERS, but these are large hot powerful and expensive gas lasers. It would be possible to combine several monochromatic LEDs in one case to make a white LED, but this is frought with problems. The different colors age and respond to heat differently. These effects would have to be compensated for in the device to assure that the "color" of the white light remained "white" from hour 1 to hour 100,000, from freezing temps to hot temps, and from low current to high current.