New brighter Nichia LEDs in summer 2004

Nichia plans to mass produce both 5mm and surface mount LEDs this summer that are 1.7 times brighter than their current production LEDs. The article is here. The efficiency of the new LEDs is said to run from 35 up to 50 lm/W. The LEDs are the usual blue + phosphor design. Most of the efficiency gain was by increasing the amount of light extracted from the blue LED die (the article mentions transparent electrodes, for example). I've heard the largest barrier to more efficient LEDs is extracting light from the die. Some current LEDs turn nearly 100% of the electrons into photons but most of this light is lost through total internal reflection and absorption.

It's nice to finally see LEDs in production that are as efficient as some of the smaller size fluorescent tubes. According to an article I read about a year ago, next year Nichia will up the efficiency again to around 60 lm/W.

Argh ... /ubbthreads/images/graemlins/icon15.gif all my 5mm lights will be dim ... /ubbthreads/images/graemlins/frown.gif
/ubbthreads/images/graemlins/grin.gif
bernhard

Interesting. I think that the article has an error when it says that the old LED flashlight was on the left. at least I THINK I can tell my left from my right (at least after thinking for a few moments /ubbthreads/images/graemlins/smile.gif )

they say that the Vf for the surface mount ones is 4+v but they don't say for the regular 5mm size. So if they have upped the forward voltage that will make it difficult to put them into the same circuits that we use now without some tweaking... except for the current regulated ones which will just adapt /ubbthreads/images/graemlins/grin.gif course, it will lower their efficiency ever so slightly. But thats OK by me. I want some!

If that really is Lumens per Watt, changes in Vf are accounted for, right?

While such improvements are welcome indeed, I hardly think it's cause to dump the current ones. I suspect it'll be hard enough to pick one out in a side by side A/B test, let alone the next day (hey, this isn't as bright as it used to be...).

Rather, I think the bright ones are getting dimmer all along as they age (and nobody notices), the improvement will be more emotional than practical.

Or so I see it.

Doug Owen

You can find some more details here:

Nichia Rigel SMT LED

Oops, wrong thread, go see it in the other one posted earlier.

(guess thats what happens when you have two threads open at once)

They need to work on LED life more than brightness, IMO. The white Nichias have a useful life a lot lower than advertised.

Thats for the old Nichia 5mm LEDs like they used in the ARC AA and AAA. Especially when overdriven (beyond the recommended 20mA, like the +55mA that ARC runs them at).

BTW, 357, exactly what does Nichia publish for the life of the old 5mm? Can you provide a link to Nichia's life claim? It took me awhile before I got the info from them, and they didn't claim anything. Just showed a bunch of charts showing lumen depreciation over time under various circumstances. I think the claims are more from the manufacturer that is using the Nichia 5mm...

These new ones are alot better. If you take a look on these new LEDs, you'll note the encapsulant is silicone...no more epoxy degredation mechanisms. Plus the copper heat tab for direct soldering, just like a D-PAK power MOSFET.

[ QUOTE ]
jtr1962 said:Some current LEDs turn nearly 100% of the electrons into photons

[/ QUOTE ]

A cute explanation .-)

And further: The phosphors in white LEDs are also quite efficient (don't forget that Nichia and Phillips (read: Luxeon) have quite a history in fluorescent lighting), pretty close to 100% IIRC.