Iām 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. Iād like to see djozz test it! :partying_face:
After quick look it looked like a winner.
But looking closer: itās 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 donāt expect it to challenge Osrams but Iād like to see it tested as well.
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)
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.
Similarly, you can use lumens instead of cd over the die but you still need to know the size of LES.
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)
Letās 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