LED technology hasn’t progressed in 10 years or so?

[Shock&Awe]

Is it true that LED technology hasn't progressed in tens of output and efficiency in the last decade or so?
I'm asking this because I bought the Zebralight SC700d around 7 years ago, and recently I was looking for an improved replacement but I was surprised to see that the SC700d is still one of the best EDC 21700

 

[bykfixer]

It platued when batteries could not keep up with draw without exploding. Maybe 2019-ish? Now everything with super nova output is regulated to step down before the hand grenade with the pin pulled explodes.

I've read about some water cooled numbers but overall the heat factor has not been overcome.

LED technology hit a hard wall that physics won't let it go past. They get hot.

 

[cave dave]

CRI's have gotten higher, but getting more spectrum requires more phosphor which reduces luminous output.
This is an older article but it discuses maximum theoretical efficiency.

Efficiency of LEDs: The highest luminous efficacy of a white LED

What does the luminous efficacy depend on and how efficient can a white LED actually be?

www.dial.de

Much of the higher claimed lumen outputs these days are based on higher drive currents for very short burst periods. Zebralight does have a burst but doesn't overdrive as much as other manufacturers and their latest focus and customer base seems more interested in high CRI and Neutral color temp.

Other random thoughts / gripes:
LED's have gotten brighter (more lumens) and slightly more efficient by making the die sizes larger, but that comes at the expense of focused beam and throw. So my small AAA and AA size lights are floodier than back in the day. Sometimes that is OK like when inside the house, but outdoors some of my older "dimmer" flashlights reach farther down the path. Some of the domeless LED technology seems to bring back some of that throw.
The circuit regulation matters a lot for efficiency as well, and many manufactures aren't trying very hard. Zebralight still cares about high efficiency circuits.
Also household LED bulbs are cheaper but crappier. They seem to burn out, flicker or grey out in a year or two.

 

[orbital]

+

A Luminus SBT90.2 using 15V can do 100W from a single emitter.
In the right light/reflector, it's really something.

There are some very large die emitters like the NB90.16 that off a single high amp 26650 // 21700 puts out truly bananas amount of light,
that's why we have ramping & multi-modes.


Luminus SBT90.2

 

[LEDphile]

The last decade or so has seen an almost doubling in allowable current densities for the chips, along with improvements in phosphors do achieve higher CRI without as much of an efficacy penalty (the phosphors effectively spread the energy from the LED die around, so that the typically blue peak is now broader spectrum. But they don't create energy, so broadening the spectrum results in lower peaks in the output and shifting energy to the edges of the spectrum where the eye is less sensitive reduces lumens. Tailoring the response of the phosphors and increasing the conversion efficiency has reduced the output hit). There's also the relatively steady march of a few percent increase in efficiency a year.

OTOH, LEDs are now commodity, where $/lumen often matters more than total number of lumens or lumens from a single emitter, and that has driven a shift from high power LEDs down to mid power LEDs which don't have the lumen output of the high power packages, but score much better on the lumen/$ scale.

 

[orbital]

The last decade or so has seen an almost doubling in allowable current densities for the chips, along with improvements in phosphors do achieve higher CRI without as much of an efficacy penalty (the phosphors effectively spread the energy from the LED die around, so that the typically blue peak is now broader spectrum. But they don't create energy, so broadening the spectrum results in lower peaks in the output and shifting energy to the edges of the spectrum where the eye is less sensitive reduces lumens. Tailoring the response of the phosphors and increasing the conversion efficiency has reduced the output hit). There's also the relatively steady march of a few percent increase in efficiency a year.

OTOH, LEDs are now commodity, where $/lumen often matters more than total number of lumens or lumens from a single emitter, and that has driven a shift from high power LEDs down to mid power LEDs which don't have the lumen output of the high power packages, but score much better on the lumen/$ scale.

+

well said ^^

Look at the tiny Osram emitters available now, years ago the xp-e could only be driven to like 1.2A,
that same size die from Osram can be driven to around 5A for a great pocket thrower.

Emitters have become more robust

 

[KITROBASKIN]

One future progression: tiny Osram emitter with satisfying color rendering.

 

[vicv]

One future progression: tiny Osram emitter with satisfying color rendering.

If they made a W-2 with CRI of 90 and color temp of under 5000 K, that's the only LED I would buy

 

[vicv]

+

A Luminus SBT90.2 using 15V can do 100W from a single emitter.
In the right light/reflector, it's really something.

There are some very large die emitters like the NB90.16 that off a single high amp 26650 // 21700 puts out truly bananas amount of light,
that's why we have ramping & multi-modes.


Luminus SBT90.2
View attachment 58485

Do you mean 15A, because that's a 3v led. If so, even 15A is taking it pretty easy

 

[orbital]

Do you mean 15A, because that's a 3v led. If so, even 15A is taking it pretty easy

+

15 or 16V ~ ex: an Acebeam K65 GT
That light does four 18650 in series for 16V fully charged.

One of the best lights ever made.

 

[jtr1962]

The real progress has been in CRI and cost. Now you can get 90+ CRI at over 200 lpw. Mid-power LEDs are now under one cent in large quantities, basically not much more than commodity parts like resistors.

Maximum efficiency for commercial LEDs is around 230 to 240 lpw. This hasn't gone up much in a long time. As others have said, we're bumping up against hard physical limits.

 

[vicv]

+

15 or 16V ~ ex: an Acebeam K65 GT
That light does four 18650 in series for 16V fully charged.

One of the best lights ever made.

Ah. Nice. I have the convoy L7. So 2s. With a 20 amp buck driver. The light is sick.

 

[orbital]

One future progression: tiny Osram emitter with satisfying color rendering.

If they made a W-2 with CRI of 90 and color temp of under 5000 K, that's the only LED I would buy

+

Roscolux tint filter #304, it's the best to make a great neutral tint, no yellow.
I'v tried many and the 304 wins

https://www.adorama.com/ro304.html

 

[cave dave]

What about "flip-chip" technology? I don't understand what that means, but claims are 20% less energy consumed and longer lifespans.

Here is an interesting article on dome-less LED's and round LED's focusing better.

https://luminusdevices.zendesk.com/hc/en-us/articles/15571205799181-What-LED-Optical-Characteristics-Are-Best-for-Directional-Lighting

Note: I just realized the above article is comparing different reflector sizes when showing the beam-shots and results. That's pretty stupid (and unscientific)

 

[orbital]

+

This isn't chip advancements, but the overall performance of current lights.

Lager lithium batteries can sustain higher Amperage currents, this allows for the incredible light output one can get today's LEDs'
26650 can do up to 30 Amps continuous
21700 can do do up to 35 Amps continuous
______Until recently, you had to choose either lower Amps higher runtime or higher Amps lower runtime for batteries.

Just yesterday I took delivery of some Samsung 50S 21700s'
They are 5000mAh @ 25Amps continuous

That is the perfect balance of runtime to strong output, nothing really compares.
Got them specifically for my Amutorch XT60 with uses the NB90.16 emitter I mentioned above.

_______________

 

[LEDphile]

What about "flip-chip" technology? I don't understand what that means, but claims are 20% less energy consumed and longer lifespans.

Here is an interesting article on dome-less LED's and round LED's focusing better.

https://luminusdevices.zendesk.com/hc/en-us/articles/15571205799181-What-LED-Optical-Characteristics-Are-Best-for-Directional-Lighting

Note: I just realized the above article is comparing different reflector sizes when showing the beam-shots and results. That's pretty stupid (and unscientific)

Flip-chip basically means using direct connection between the electrical pads on the die (on the top of the die) and the package. It's been standard for high-power blue, green, and phosphor-converted (e.g. white) LEDs for over a decade.

And for directional light sources, the ratio of source size to the size of the collimating optics is roughly constant for a given beam angle. So a smaller source means a narrower beam for the same size collimator, or a smaller collimator for the same beam angle.

 

[letschat7]

Super bright lights get very hot and no one wants a big light but smaller and smaller. What if we had a high CRI 500 lumen light that ran nonstop for a month or months even?

 

[vicv]

+

Roscolux tint filter #304, it's the best to make a great neutral tint, no yellow.
I'v tried many and the 304 wins

https://www.adorama.com/ro304.html

I have some lee filter. It's nice. But it's not the same as a high cri