Future development of the maximum luminance of LEDs

Luminus SST-20 CRI95 seems to be over 100 cd/mmĀ² though the precision of my calculations is too low to call it definitive:

CRI70 variant is over 100 for sure. Iā€™m sure Iā€™ve see it tested somewhere but canā€™t find it nowā€¦.

.

Boost HX or colored flat?

Looks like 1 mmĀ²!!??
Havenā€™t heard about it before but CULNM1.TG is a thing:
https://www.arrow.com/en/products/kw-culnm1.tg-z8pf5-ebvffcbb46-65g5/osram-opto-semiconductors
ADDED:
And Osram is phasing it out:
https://www.mouser.com/PCN/Osram_Opto_Semiconductor_1_cip_OS_NFND_2018_008.pdf
:smiley:

4040-size and 1mm2 die, hmmm :neutral_face:

Throw the bone to the dogs L4P :smiling_imp:

It looks like 2mm2 led to meā€¦ But lets wait and see what will L4P say.

1 mmĀ², CULNM1.TG aka Boost HL. And itā€™s already tested:

Than it seems we spammed The Drivers thread :innocent:

I already added it and linked to the test.

Iā€™m guessing this is nothing too interesting:

https://www.samsung.com/led/automotive/automotive-leds/i-series/3w-white/

Iā€™m not too adept at reading datasheets to determine such things though.

Iā€™m not that great at Datasheets either. But it seems to have package size just a bit bigger than XP, and die size about the same as OSRAM White Flat. It is rated for 385lm from 3.0V and 1.0A current. Iā€™d like to see djozz test it! :partying_face:

After quick look it looked like a winner.
But looking closer: itā€™s rated for mere 1.5A which seemed suspicious (White Flat is 3A).
Output scales nicely with current but Vf grows fast. So efficiency drops quickly.

I donā€™t expect it to challenge Osrams but Iā€™d like to see it tested as well.

According to manufacturer, Getian GT-FC500X3-3.0 does 100-120 cd/mmĀ². :slight_smile:

Can someone share some ways to measure or calculate [cd/mm2]?

I know how to measure cd and know my area size.
I have lumen tube, lux meter, laser power meter, and other equipment.

I never got around to actually calculating this value but now it is quite important to know because I am building LEP

Regards Xandre

Several ways.

  1. There are calculators from Enderman that let you estimate throw. You can use them in reverse, adjust luminosity so it matches your actual measurements:
    Reflector Type 1 (metric)
    Lens Type 1 (metric)
  2. A more direct way is to ditch optics and measure cd over bare die. This however requires to know your light emitting surface area. Which is frequently hard to establish with many LEDs emitting not only from the top but also from the sides and can lead to large errors.
  3. Similarly, you can use lumens instead of cd over the die but you still need to know the size of LES.

Thanks for the information.

Sorry, I am still a little confused on how to put everything together.
Like how you can get throw from know Lux and Distance alone, is there a way to know die illuminance in a similar way?

@Xandre
I have a lumen tube that can get OTF lumens. However, I do not have an integrating sphere so I am unable to get exact lumen measurements from the bare die I am trying to measure.
Do I enter 180deg as my apex angle?

@Agro
If I were to measure a bare die with a Lux meter, what would the general equation be?
Would I need to measure at different angles to know my emission pattern in an equation?

For example:
Lux meter @ 1meter = 150lux
die area = 0.04mm2

150 lux @ 1m = 150cd
150cd / 0.04mm^2 = 3750cd/mm^2 (very unrealistic, only short arcs can get this intense, LEDs are 10x less)
Anyway, you multiply that by the front area of your reflector/lens (again in mm^2) to get cd again.
(For example a 25mm diameter lens has area 491mm^2, which would be 1.8 million cd with that impossible tiny LED)

Letā€™s ignore the optic and just focus on the 150cd from earlier.
You use cd to get the throw using the inverse square law of light.
(150cd / 0.25) ^0.5 = 24.5m
This is the distance where your luxmeter would read 0.25 lux (ANSI standard for throw)

You can also check in reverse:
24.5^2 = 600, which means the lux at 1m is 600x higher than that at 24.5m
And 600x 0.25 = 150 lux @ 1m

Wwow.
I just realized after reading your explaination. All I literally had to do was divide by my surface area! cd / area! Lol

Thank you so much for showing the relations between lux and cd. Everything finally makes sense.

Yup!
No prob :slight_smile: