? when the FIXED white 5 watt LEDs will be out?

[Orion]

Thanks Kurtos. I went to that site, and the only PR base bulbs they have look like plain ol' Krypton bulbs and only show 50 hours of average life.

Okay, so for the 'fixed' white 5 watt Luxeons, we're looking at the end of this year? If that is true, I can wait that long.

Though part of me wonders if they can't fix the problem, hence the reason for the 3 watt LEDs coming out soon. /ubbthreads/images/graemlins/thinking.gif

 

[markus_i]

Hmmm - I'd think the reason for the 5 Watters in their current configuration was that they couldn't get the power from a single chip. Now that they can get at least 3 W from one chip, I'd guess
- the new 3W will become the dominant line (easier manufacturing, better collimation, less cost)
- a multi-chip LED based on the 3W will appear some time later (but I won't bet on whether it'll be a two-chip at around 5W or a four chip at 8...10 W)
- the current 5W will disappear, either through market pressure or executive decision - I just don't see a niche for it
- depending on the price of the 3W, the 1W may be ramped down, too

I see the current 5W mainly as a crutch - marketing sold something, so engineering was forced to deliver, no matter what or how.

And no, I don't work for them and there is no inside information in the above, just some wild speculation.

Bye
Markus

 

[Orion]

So, speculation would say that they produced the 5 watt LED, worked well for colored LEDs, but for white, they couldn't get the heat issue solved. So, they came out with a "1 watt LED on steroids", or the 3 watt LED, perhaps knowing that they couldn't resolve heat issue.

So, if they have issues with heat, when using multiple dies to make a 5 watt, then logically, the same thing will happen if they try to take the 3 watt and put them together for a higher wattage LED. Correct?

Sometimes I wonder IF it's even possible for Lumileds [or whoever] to go beyond where we currently are in LED technology. If that's the case, that will be sad because I've grown to want LED based lights more and more everyday, and if the apex is reached, so goes my hobby. /ubbthreads/images/graemlins/frown.gif

 

[kakster]

Maybe, one day in the not-too-distant future, someone will figure out the chemical combination that will allow full spectrum white LEDs without the need for phosphor between the lightsource and the outside world.

 

[PhotonBoy]

Sandia's quantum dots

"ALBUQUERQUE, N.M. — In a different approach to creating white light several researchers at the Department of Energy's (DOE) Sandia National Laboratories have developed the first solid-state white light-emitting device using quantum dots. In the future, the use of quantum dots as light-emitting phosphors may represent a major application of nanotechnology."

 

[Blue_Shift]

This thread is depressing...

 

[Entropy]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
Orion said:
So, speculation would say that they produced the 5 watt LED, worked well for colored LEDs, but for white, they couldn't get the heat issue solved. So, they came out with a "1 watt LED on steroids", or the 3 watt LED, perhaps knowing that they couldn't resolve heat issue.

So, if they have issues with heat, when using multiple dies to make a 5 watt, then logically, the same thing will happen if they try to take the 3 watt and put them together for a higher wattage LED. Correct?

Sometimes I wonder IF it's even possible for Lumileds [or whoever] to go beyond where we currently are in LED technology. If that's the case, that will be sad because I've grown to want LED based lights more and more everyday, and if the apex is reached, so goes my hobby. /ubbthreads/images/graemlins/frown.gif

[/ QUOTE ]
As far as anyone can tell, the 3W dies are exactly the same as the 1W dies, they just have packaging with improved heat transfer properties. I believe some of the packaging improvements for the 5W were "backported" to the 1W, creating the 3W.

 

[Orion]

Re: ? when the FIXED white 5 watt LEDs will be out

Yes, but don't the new 3 watters have the same fV as the 1 watters? There would have to be something other than the heat transfer properties, wouldn't there? /ubbthreads/images/graemlins/confused.gif

 

[McGizmo]

Re: ? when the FIXED white 5 watt LEDs will be out

Hi guys,

As has been discussed in other threads, it is inherently misleading to "tag" a LED by its "power in" rating. I for one have no problem using the identifiers of 1W, 3W and 5W for the Luxeons but I rarely consider the wattage as useful or meaningful information. The lower the Vf of a LED, the more efficient it is when driven at a specified current (relative to a unit with higher Vf) and yet the lower, the resulting wattage, comparatively. Equating wattage consummed with luminous output is often contrary. Think of the 1W as die "x". The 3W then from what can be gathered is "x" with higher permissible input currents. The 5W is basically "4x".

I think most important here is sustainable lumens/watt in real world applications. As the new 3W's make it into population, we should beable to determin from experience if there has been an improvement or "super 1W" brought to market.

I still get a kick out of this subject title as I consider some of the poor thermally managed lights out there as well as some of the overdriven applications as having more bearing on the ultimate health of the LED's than whether or not their basic design has been "fixed" /ubbthreads/images/graemlins/grin.gif

- Don

 

[Entropy]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
Orion said:
Yes, but don't the new 3 watters have the same fV as the 1 watters? There would have to be something other than the heat transfer properties, wouldn't there? /ubbthreads/images/graemlins/confused.gif

[/ QUOTE ]
Since they have better heatsinking, they're rated at twice the current.

Remember that the V/I curves for diodes (including LEDs) are highly nonlinear. Up to a few tenths of a volt below Vf, they conduct almost nothing, at Vf they conduct their rated current, and a few tenths more they conduct many times their rated current. So a die rated with a Vf of 3.3v and a current of 350 mA can be rerated as (as an example) a Vf of 3.4v and 700 mA. (Maybe slightly higher Vf). The key with the 3W units is that the packaging improves heatsinking so that it can handle those higher currents.

Note that the 1W and 3W ratings are approximate. I believe the 1W blue/white/green/cyan Luxeons run closer to 1.25 watts, and the 3Ws probably run slightly less. 1/3/5 just happen to be nearby round numbers.

 

[Orion]

Re: ? when the FIXED white 5 watt LEDs will be out

When Wayne showed the picture of the Tri-lense using 3 1 watt stars, and another picture of the Tri-lense using 3 3 watt stars, the 3 3 watt combo was much brighter, and with [I'm assuming] the same battery configuration. So, I guess the 3 watt stars are just utilizing the power from the batteries better?

 

[Entropy]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
Orion said:
When Wayne showed the picture of the Tri-lense using 3 1 watt stars, and another picture of the Tri-lense using 3 3 watt stars, the 3 3 watt combo was much brighter, and with [I'm assuming] the same battery configuration. So, I guess the 3 watt stars are just utilizing the power from the batteries better?

[/ QUOTE ]
More appropriately, abusing the batteries more severely.

The 3W Stars consume twice the current at a somewhat higher Vf.

3x3W has to be drawing a LOT of current from the batteries. /ubbthreads/images/graemlins/smile.gif

 

[Orion]

Re: ? when the FIXED white 5 watt LEDs will be out

Hmmmmm. So, . . . . Would I then assume that the 3W star pulls more from the battery, making a 3 cell direct drive frowned upon? I know a lot of modders take a 1W star and use 3 cells for their power, overdriving it. Is the same over driving for the 3W star going to be more problematic? /ubbthreads/images/graemlins/confused.gif

 

[highlandsun]

Re: ? when the FIXED white 5 watt LEDs will be out

Sounds to me like it will be less problematic, as the batteries will probably max out before the 3x3W are fully juiced...

 

[AilSnail]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
I still get a kick out of this subject title as I consider some of the poor thermally managed lights out there as well as some of the overdriven applications as having more bearing on the ultimate health of the LED's than whether or not their basic design has been "fixed"


[/ QUOTE ]

If the dies are the same in 1w as in 5w, why does the 5w have so much shorter life? Epoxy lens degradation?

 

[Doug S]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
AilSnail said:
[ QUOTE ]
I still get a kick out of this subject title as I consider some of the poor thermally managed lights out there as well as some of the overdriven applications as having more bearing on the ultimate health of the LED's than whether or not their basic design has been "fixed"


[/ QUOTE ]

If the dies are the same in 1w as in 5w, why does the 5w have so much shorter life? Epoxy lens degradation?

[/ QUOTE ]
I suspect that if you were to operate a 1W and 5W at identical *die* temperatures that they would have the same rate of degradation ["life"]. The problem is that with the higher operating power of the 5W, practical heat sinking arrangements to do not permit as low a die temperature as can be attained by a 1W at rated conditions.

 

[AilSnail]

Re: ? when the FIXED white 5 watt LEDs will be out

[ QUOTE ]
I suspect that if you were to operate a 1W and 5W at identical *die* temperatures that they would have the same rate of degradation ["life"]. The problem is that with the higher operating power of the 5W, practical heat sinking arrangements to do not permit as low a die temperature as can be attained by a 1W at rated conditions.

[/ QUOTE ]

Interesting thought.
I think I need a definition clarification: What is the "junction" temperature, as is referred to in the data sheets? I have assumed it was the same as die temperature.

They state: Tjmax: 1w: 120C; portable: 135C; V star: 135C.

So this seems to agree with your assessment, except that the V star (5w green, blue, royal blue and cyan) has a 100k hours life, according to the sheets?
Confusing.

 

[PsycoBob[Q2]]

Re: ? when the FIXED white 5 watt LEDs will be out

(Guess mode ON) Perhaps the higher thermal density of the 4x dies is causing problems with the Phosphor. As far as I know that's the only difference between the White and GCBV 5 watters.

 

[evan9162]

Re: ? when the FIXED white 5 watt LEDs will be out

You're probably right PsycoBob.

The junction-slug thermal resistance of a 1W white is 15C/W (according to Lumileds documentation). Thus, when running a 1W at spec, the junction temp is 15C higher than the slug temperature.

The junction-slug thermal resistance of the 5W white is 8C/W, but at 5W, the junction is 40C higher than the slug.

Consider the case where both emitters are attached to a heat sinking mass with a thermal resistance to ambient of 10C/W.

At 20C room temperature, the 1W heat sink will be at 30C, and the junction temperature at 45C.
However, the 5W heat sink will be at 70C, with the junction temperature at 110C.

The phosphor is nestled right up against that 110C heat source. The 5W white is literally frying the phosphor to nothing.

In order to keep things under control, a heat sink with 1/4 the thermal resistance to ambient needs to be used, and the junction-slug resistance needs to be 1/4 of what it is in the 1W. Both of those would bring the junction temperature of a 5W down to the same level as the 1W. That, or a more resistant phosphor needs to be developed that can handle the heat for extended times.

 

[Doug Owen]

Re: ? when the FIXED white 5 watt LEDs will be out

Intersesting idea. If true, though, one would expect the phosphor death would cause a shift to blue. That is the LED itself should be fine, just a somewhat dim blue, but not open or shorted. What do 'dead' ones look like?

FWIW, one of the phosphors used is YAG, and it's happy at these sorts of temperatures (tough stuff, the G part is Garnet).....

It occurs to me that Christian (the Scientist at work collaboratign with Lumileds) might just know what's going on......

Doug Owen