This emitter has been getting a lot of attention lately, but details like its forward voltage and output are not available to the modding community yet, so I thought I would try to measure what I could. I don’t have an integrating sphere, but I can measure the approximate luminance of the die by measuring the lux at a known distance from the die and by measuring the die area.
The LED measured is a XHP35 HI E2 3C that I purchased from mtnelectronics. The measurement apparatus consisted of the LED on a CPU heatsink with a lux meter mounted 38cm directly above the LED. I used my constant current power supply to power the LED. I started at low current and stepped up the current in 0.1A intervals. I took a measurement about every 7 seconds. At the end of the test, the heatsink was slightly warm. The voltage was measured at the MCPCB solder points.
I did my best to measure the die size with some calipers. I measured 2.49mm, for a die area of 6.20mm^2. To get the luminous intensity (cd), I multiplied the measured illuminance (lux) by (0.38m)^2. Then I divided by the die area to get the luminance (cd/mm^2).
For a bit more information about this measurement method see this thread I made about the luminance of the XPL V6 1A as a function of silicone sliced off. At 5.5A, I measured the dedomed XPL V6 1A to have a luminance of 141 cd/mm^2. XPL V6 1A current can be around 6A direct driven, so the luminance would be a bit above 141 cd/mm^2.
So this XHP35, driven to 2.5A, has luminance pretty close to the direct driven dedomed XPL V6 1A, which means it should be able to throw nearly as well as the XPL V6 1A.
Edit: I realized I can get a good estimate of the total output (lumens) from my measurements with a bit of math trickery. Because the radiation from the LED is distributed in angle in a known pattern (it is very close to a Lambertian surface), I can derive the total output if I know the luminous intensity directly above the LED. Some more information about this method below in post #19.
So here is the derived output. It has the same shape as the luminance curve.