In what percentage do the various LED brightness groups occur?

[treez]

Hello,
Page 5 of the osram power toppled datasheet says that the power toppled can occur in 4 different brightness groups.
The brightness of these groups differs by 100%.

What percentage of a typical manufacturing batch of leds occur in each of the brightness groups, ?..or is this unknown?

Power toppled datasheet:
**broken link removed**

 

[yassin.kraouch]

this is really unknow even the LED manufactrer cannot predict the brightess group that will be available,
it is very dependant on the manufacturing condition,

 

[treez]

. U.S. Department of Energy (DOE) tests of commercial LED lamps designed to replace incandescent or CFLs showed that average efficacy was still about 30 lm/W in 2008 (tested performance ranged from 4 lm/W to 62 lm/W).[99] Solid-state lighting continues to improve; in June 2011 the 8 products in the A-line bulb configuration that DOE tested[100] ranged from 50 to 97 lumens per watt, with an average of 62 lumens/watt.

https://en.wikipedia.org/wiki/Compact_fluorescent_lamp

The USA DOE were testing efficiency of LED light bulbs by measuring lumens /watt.

As we appear to agree, this is a completely bogus measurement, as the leds in those bulbs might have been the very brightest lot of the production batch. (ie, far brighter than more normal leds from the production batch)

Why did they not look into actual V*I product across the LED load? and use that as output power, and compare it with input power, to get efficiency?

 

[Audioguru]

Like your hearing's sensitivity, your vision's response to brightness is logarithmic. Then you can see in moonlight and in sunlight (without the effect of the iris making the range even more). So double the lumens as in the datasheet for the LED does not change its brightness very much, just a little.

 

[treez]

i see your point, but everybody is talking about breaking the 200lm/w mark....if were saying that 100lm/w is just as good (nearly), then it hardly seems worth while?

 

[yassin.kraouch]

https://en.wikipedia.org/wiki/Compact_fluorescent_lamp

The USA DOE were testing efficiency of LED light bulbs by measuring lumens /watt.

As we appear to agree, this is a completely bogus measurement, as the leds in those bulbs might have been the very brightest lot of the production batch. (ie, far brighter than more normal leds from the production batch)

Why did they not look into actual V*I product across the LED load? and use that as output power, and compare it with input power, to get efficiency?

yes you are right when testing the LED bulb light output, they can use the highest bin flux, but the reality will not be the same, it will have lower lumen output,
and to measure the V*I, is not a solution to judge the output power of LED, because two LED with the same forward voltage, can have different flux bin

 

[treez]

yes but you have to have some basis for efficiency ...and finding the drivers efficiency can be done by first measuring v.i of led load...then comparing to input power.

 

[yassin.kraouch]

you are confusing efficacy and efficiency, efficacy is lm/w and efficiency is %.

 

[treez]

no, i agree with that.