What's next for LED technology?

[Calina]

there's food for thought. So what is the latest and greatest in the lab today? It should be roughly double the output or efficiency or half the size for the same output, if LED technology follows Moore's law more or less...

Here are some recent lab's results: https://www.candlepowerforums.com/threads/227757

 

[PhotonWrangler]

I just came from a trade show where they had a number of LED fixtures for architectural lighting and streetlights. While some of the fixtures seemed bright, they were still in the "almost ready for prime time" category in terms of streetlights.

 

[Curt R]

On 2 Feb 2009, Seoul and Nichia have signed a cross-licensing agreement. Seoul signed a cross-licensing deal with Austrian LED maker Tridonic, and Nichia signed a deal with Sharp. Cree has also resolved its differences with US LED maker Bridgelux. Nichia wanted the Seoul Acriche product technology and Seoul wanted some of Nichias tech. The end result is that the Seoul P4 V bin chip has been put back from its Jan 2009 release as Nichia technology is incorperated. I am not allowed to say what it is as Seoul wants to make their own headline announcement. The rest of this year may be very interesting. :twothumbs

Curt

 

[AvPD]

I am not allowed to say what it is as Seoul wants to make their own headline announcement.

Where do you work?

 

[Ryanrpm]

This is pretty new: A company called Sunlite has emitters that are not encased in a dome.....but rather have some thermal epoxy over them. The result is a light source that is smaller, allowing for tighter focusing when contained within a reflector.

The company has been making flashlight LED's since 2005, and have recently released a high output far projection light called the Eagle 16w. Here's a few shots of the emitter for those interested:

Remember, no dome at all, just thermal epoxy covering those emitters. This particular light has 4x60mil chips. They have also been able to do what no other LED manufacturer can do and that is to remove the gap between the chips. I guess all others must have theirs significantly separated to electrically isolate them.....but Sunlite has developed a way around that.

Here's a shot of the MC-E and P7 and even the Ostar 6 chip to show you what I mean.

Anyways.....just food for thought....

 

[znomit]

They have also been able to do what no other LED manufacturer can do and that is to remove the gap between the chips. I guess all others must have theirs significantly separated to electrically isolate them.....but Sunlite has developed a way around that.

I do see a gap between the dies.
I also see about 300lm from 8W :duh2:

 

[Ryanrpm]

I do see a gap between the dies.
I also see about 300lm from 8W :duh2:

Sorry friend, you are not seeing a gap. The faint lines are where the emitters meet together. Unless you create a single large chip, packing more than one together will give you a faint distinct line where they meet together. However, I could be wrong about that...but no other manufacturer has proven otherwise.


And I'm not following you on the 8w/300lumen comment?:shrug:

 

[jtr1962]

And I'm not following you on the 8w/300lumen comment?:shrug:

He might be alluding to the huge crop of multi-die emitters out there which mostly have disappointing efficiency numbers. To me making an emitter which puts out 3000 lumens is no great feat if you only end up with 40 lm/W.

 

[znomit]

And I'm not following you on the 8w/300lumen comment?:shrug:

I just followed your links to the sunlights. 8W 300lm on turbo, couldn't see the 16W.
http://www.powerledlighting.com/Eagle8W4400.html

If you shrink your huge MC-E pic it looks like the big black cross in the middle is not too different from the Sunlight, it just looks better defined on the Cree because there's no phosphor in the gap.

 

[Ryanrpm]

I just followed your links to the sunlights. 8W 300lm on turbo, couldn't see the 16W.
http://www.powerledlighting.com/Eagle8W4400.html

If you shrink your huge MC-E pic it looks like the big black cross in the middle is not too different from the Sunlight, it just looks better defined on the Cree because there's no phosphor in the gap.

The 16w is not officially released for public purchase yet. I guess my intentions for jumping in here on this "New LED technology" wasn't to bring any new beakthrough in "efficiency" to the discussion.....but more to show a quite unique process by a company that makes specific applications with their LED's.

1) Using no dome over the emitter.
2) Using multi-emitters packed closer than any other manufacturer. (Our tiffs on whether there is no gap between them, or a streak of phosphor.......i don't know. I only know what they told me in an email upon sending me the 16w to test out. I'll inquire to them for more information )

Also, please keep in mind, that the terms "8w" and "16w" are really the names they gave their lights, and do represent the potential they can be powered to........but are not accurate as far as what they currently are powered to.

 

[bshanahan14rulz]

Hey, I still think that domeless quad-die is awesome! its like a quad-die with the apparent size a little bigger than a single chip domed LED. Only bad thing is I'd be too curious and want to touch it when it's on. you know, for kicks. expensive kicks.

 

[Ryanrpm]

1) Using no dome over the emitter.
2) Using multi-emitters packed closer than any other manufacturer. (Our tiffs on whether there is no gap between them, or a streak of phosphor.......i don't know. I only know what they told me in an email upon sending me the 16w to test out. I'll inquire to them for more information )

Ok, so I inquired and they responded......

Here is their quote: "We put the LED chips side by side. There is no physical gap between them. Since each chip has a 50 micron wide passivation peripheral to protect the active area, there is about 0.1mm wide no-light area in between."

 

[bhvm]

Why don't they make LED bulbs with the phosphor on the glass and the die where the filament would be, like florescent?
The phosphor would run cooler and would be converting far less blue to white light so perhaps would be much less droopy?

Excellent suggestion Mr!!

That would truly start the spark where we need diffused lights and not point lights. I see Applications like Indoor lights, reading lights, Tubelight replacements etc.. taking huge benefits@!

 

[Gryloc]

I think it is great to see other companies creating LED emitters. I wish that Sunlite became more public, or would allow us to buy their emitters separately. Their products do seem interesting, as they seem to focus on developing LEDs mainly for flashlights, while the top manufacturers have general lighting customers in mind (Lumileds, Cree). Actually, is that correct? I guess I do not know enough about this company. I wish they had more presence here on the CPF (instead of just through you, Ryan) to increase awareness in their products.

Anyway, even if there is not physical gap in the LED, there will still be a dark spot on the emitting surface in ths shape of a cross. Unfortunately, because of this cross, where the two darker lines meet, is right in the optical center of the LED. So, when you focus the reflector so the focal point is lined up axially above or below the optical center, you will still get that notorious "donut hole" in the flashlight's beam. This will have a donut hole like every other quad die of the past, but I wonder if the donut hole will be less evident since the gap was removed and the only limiting factor left is the effect of the passivation peripheral. Lumiled's Luxeon V did not have that bad of a donut, and the SSC's P7 had a donut that wasn't too unbearable. However, because the MC-E uses dies with a confomal coating, and because the gap is actually larger than with the P7, the beam is rather horrid with a smooth reflector. If you make comparable measurements of the die image of these multi-die emitters, you will see how the gap size vary.

It would be neat to see them produce a LED in response to Phlatlight's newer products. If Sunlite makes their own emitters, then what if they use a new process to grow larger sized dies? I thought that Sunlite had a model of emitter with a slightly larger die, or am I thinking of another manufacturer? A 5mm^2 or 9mm^2 would be nice. Actually, I can imagine that it would be more practical to push 9 of their dies together like they did with this new quad die. With 9 dies together, there would not be a donut hole in the flashlight beam, but instead maybe a ring in the beam that would appear slightly dimmer (think a bigger donut hole, but most of the hole is filled with the light of the center die). This would happen because the there would be a die in the optical center, then moving outwards, there would be a grid of darker lines surrounding it, and finally a perimeter of dies.

Finally, could you share if Sunlite uses Flip Chip technology like Lumileds uses with their TFFC-based products? This would explain the absence of bonding wires. Without bond wires, how are the dies electrically connected? Lumileds uses electrical contacts on the underside of the die, and uses vias, and Cree still did not flip their chips yet (why not?) and still mount their dies on SiC and use bond wires. Because Sunlite has their dies physically touching, then that must mean that all four dies are wired in parallel, right? A gap was neccesary with Lumiled's Luxeon V because two sets of dies were wired in series while two were in parallel. I still wonder why Lumileds do not have a Rebel-like product (using an alumina substrate) where they connect four touching dies in parallel. I guess this is because of the cost and practicality to use multiple, separate, and matched dies prohibits this...

Thanks for the info on the Sunlite emitters. Too bad you could not encourage one of the employees to join the CPF to share their products, or maybe more in depth info (just specs and basic info that you would see on a datasheet).

-Tony

 

[Ryanrpm]

I think it is great to see other companies creating LED emitters. I wish that Sunlite became more public, or would allow us to buy their emitters separately. Their products do seem interesting, as they seem to focus on developing LEDs mainly for flashlights, while the top manufacturers have general lighting customers in mind (Lumileds, Cree). Actually, is that correct? I guess I do not know enough about this company. I wish they had more presence here on the CPF (instead of just through you, Ryan) to increase awareness in their products.

Anyway, even if there is not physical gap in the LED, there will still be a dark spot on the emitting surface in ths shape of a cross. Unfortunately, because of this cross, where the two darker lines meet, is right in the optical center of the LED. So, when you focus the reflector so the focal point is lined up axially above or below the optical center, you will still get that notorious "donut hole" in the flashlight's beam. This will have a donut hole like every other quad die of the past, but I wonder if the donut hole will be less evident since the gap was removed and the only limiting factor left is the effect of the passivation peripheral. Lumiled's Luxeon V did not have that bad of a donut, and the SSC's P7 had a donut that wasn't too unbearable. However, because the MC-E uses dies with a confomal coating, and because the gap is actually larger than with the P7, the beam is rather horrid with a smooth reflector. If you make comparable measurements of the die image of these multi-die emitters, you will see how the gap size vary.

It would be neat to see them produce a LED in response to Phlatlight's newer products. If Sunlite makes their own emitters, then what if they use a new process to grow larger sized dies? I thought that Sunlite had a model of emitter with a slightly larger die, or am I thinking of another manufacturer? A 5mm^2 or 9mm^2 would be nice. Actually, I can imagine that it would be more practical to push 9 of their dies together like they did with this new quad die. With 9 dies together, there would not be a donut hole in the flashlight beam, but instead maybe a ring in the beam that would appear slightly dimmer (think a bigger donut hole, but most of the hole is filled with the light of the center die). This would happen because the there would be a die in the optical center, then moving outwards, there would be a grid of darker lines surrounding it, and finally a perimeter of dies.

Finally, could you share if Sunlite uses Flip Chip technology like Lumileds uses with their TFFC-based products? This would explain the absence of bonding wires. Without bond wires, how are the dies electrically connected? Lumileds uses electrical contacts on the underside of the die, and uses vias, and Cree still did not flip their chips yet (why not?) and still mount their dies on SiC and use bond wires. Because Sunlite has their dies physically touching, then that must mean that all four dies are wired in parallel, right? A gap was neccesary with Lumiled's Luxeon V because two sets of dies were wired in series while two were in parallel. I still wonder why Lumileds do not have a Rebel-like product (using an alumina substrate) where they connect four touching dies in parallel. I guess this is because of the cost and practicality to use multiple, separate, and matched dies prohibits this...

Thanks for the info on the Sunlite emitters. Too bad you could not encourage one of the employees to join the CPF to share their products, or maybe more in depth info (just specs and basic info that you would see on a datasheet).

-Tony

I have inquired for you....here is Fong Suo's response....

 

[dougmwpsu]

If I can put on my futurist hat for a moment:

The theoretical max luminous efficacy for flat white light is 240 lm/W.

Haitz's law has so far correctly predicted the increase in LED efficacy.

We're currently sitting at about 100 lm/W for neutral white Crees.

Therefore, extending Haitz's law, we have about 3-4 years to go before we're deep into the point of diminishing returns for efficiency.

From there, it's all about cost reductions.


...Greetings CPF! Sorry about the fuzzy maths.

After some quick googling I found that Haitz's Law applies to LEDs.