How much as LED technology advanced in the past five years or more?

[ampdude]

I didn't want to make a clickbait thread title, so my real intention of this thread is that I haven't noticed any huge changes in LED technology since about 2015. It seemed like things were progressing so fast from 2005 to 2015, then things just kinda dropped off. What is going on these days? I know about HCRI LED's that also existed back in 2015, and LED's oriented towards spill and throw. The 5mm LED has come up a bit in the past few years as being a far more viable light source than it was ever originally intended to be (an indicator light). What's the deal? It seems like things have really slowed down the past five years. I'm not a huge LED guy, though I do like high quality HCRI warmer tinted LED lights. I'm partial to 3400-3500K emitters. I'm more an incan/HID guy, so I'd like to do more listening to posts than talking.

 

[bykfixer]

Physics played a role. Fuel played a role and the market played a role.

Heat made it so things required an oven mitt to hold the light. Things progressed about as far as heat disipation would allow without adding a fan or liquid cooling.

Battery capacity hit a wall and until super capacitor becomes more affordable that may remain an issue. The amount of draw the batteries were capable of reached a peak and then the old "exploding battery" phenomenon caused people to decide "ok, no more hand grenades with the pin pulled please".

The market that wanted flashlights bought flashlights then sales in the big scheme of things went from near vertical increases on a graph to a near flat to downward direction by 018. The progression has remained in smaller lights though. Take the Streamlight microstream for example. In 015 it was a mighty big 50+ lumens and now boasts 250 lumens sustained. I have a 1aa light that with a certain battery boasts 900 lumens briefly and 300 briefly from a 1.5 volt Rayovac. In 015 a 2 cell CR123 light putting out 900 was a big deal.

Progression is creeping along but thankfully the huge leaps in output has the lumen wars in a lull enough to where manufacturers are focused on beam quality instead.

The positive things I see are some opting for better runtime than major output upgrades.

 

[orbital]

+

Depends on what you want or using it for.

If you tested a high voltage light, with a single SBT90.2 emitter running at around 70~80Watts,, you'll see things you never saw before in the dark.
Wow is an understatement & you just may need to do some laundry

 

[adamlau]

Progressing just fine, IMO. The potential of the SBT90.2. The throw of the OSLON Boost HX. High CRI with high output in the LH351D and XHP70.2. I don't remember any of that in 2015.

 

[orbital]

+

It's really Moore's Law for emitters.

Imagine that in Lumens / Watt ^^^^^

______________________________________________________________________________

Eventually, I see some heavy gas being added under the emitter dome
(not combustible, but to hyper energized) & turbocharge luminosity

 

[Owen]

Imagine that in Lumens / Watt ^^^^^

For real!
We've seen a dramatic increase in potential output, but not so much in efficiency.
Having fallen way out of touch with the flashlight stuff for 8yrs or so, I've been reading about some of the LEDs that get mentioned here, to learn about them.
Looking at the data sheets for the Luminous SBT90.2 and Cree XHP70.2, they're still hovering around 100 lumens per watt, but they're spec'd at ~30w(!), and get driven even harder.
That's a lot of juice to supply, and a lot of heat to dissipate...

 

[orbital]

+

Dug up some numbers:

XM-L = 158lm/W
XM-L2= 175lm/W
XM-L3 = 187lm/W

Nearly 20% increase over a handful of years.

How hard emitters can be driven now is the biggest improvement.
A new Osram (about the same size as an XP-E) can be driven at nearly 20W,,, that incredible.

 

[jtr1962]

Two major improvements over the last 5 years:

1) Efficiency improvements enable emitters to be driven harder with the same heat production. While this can't continue forever it's worth noting that even relatively small improvements in efficiency can translate into big gains in terms of heat production and output. For example, a 60% efficient emitter is roughly 180 lm/W, while an 80% efficient emitter would be about 240 lm/W. Driving the former at 20 watts will produce 8 watts of waste heat while giving 3600 lumens. To produce the same 8 watts of waste heat you would need to drive the 80% efficient emitter at 40 watts, producing 9600 lumens. So you get 2.67 times the amount of light for the same amount of waste heat with only a 1.33 x increase in efficiency. For flashlight use waste heat is the primary limiting factor as far as output goes. Today's batteries can already push far more power into the emitters than the flashlight body is capable of dissipating.

2) Cost per lumen has dropped dramatically. This is really where LEDs are following Moore's law as efficiency increases are petering out. Now you can get LED replacement bulbs for under $1. The only reason this is possible is the dramatic price decrease of LEDs.