Sharing interests with Green Building in Denver , I am pleased to find offering of interesting Conturrent™ 4" and 6" LED downlights from Amerisus . These lights are wired as low voltage direct current. Complete systems must be purchased, at substantial cost:
The 4" light is petite 250 lumens, in three color temperature ranges:
2700 to 3000°K Warm
4000 to 4500°K Cool
6000 to 8500°K Daylight
The bigger 6" light is 800 lumens, in the same color ranges.
What will we do with these? I'm privileged to try out one 4" Conturrent.
The active area of the lens is a 65.5 mm circle, area 3370 sq mm. Circle luminance is 250/3370 lumens per sq mm = 7,400 lumens per sq meter, 7400 Lux.
For this, I bought a nice 15 VDC power supply.
Just pure light within the 65.5 mm lens. I don't perceive edge glare at the diodes.
Lift out the lens stack to view the diode strip.
There are twenty diodes 3.5 mm square, giving 250 lumens. Diode area is 245 sq mm. Diode luminance is one lumen per sq mm, one million lux.
See etched back face of the thick acrylic diverter of edge lighting. The etching and a reflective top covering raise efficacy, amount unknown, but certainly not 100% transmission as productive light. Claimed 250 lumens/ 3 watts, is a really-good 83 lumens per watt. For this, diodes must put out 100 lumens per watt, or more.