Why does LED binning rating also changes Guaranteed CRI level ?

I was inspecting the Cree XHP70.2 datasheet when I noticed two things :

1. Some high CCT LEDs have high CRI levels. I thought that "Cool" tinted LEDs were emitting exclusively in blue so that the CRI was staying below 75. Also, some "warm" tints such as the 4000k ones have the same lumen output as 6000k LEDs, how ? There is much phosphor on warmer LEDs so the output should be lower right ?

2. The binning "grade" of the LEDs impact the CRI. If you want a high binning grade, such as P2, CRI is 70+. Consequently, a high CRI means a low binning, why ?

That's a lot of questions but maybe I'm not the only one interested by the answers ? Thanks !

Kivatch said:

I was inspecting the Cree XHP70.2 datasheet when I noticed two things :

1. Some high CCT LEDs have high CRI levels. I thought that "Cool" tinted LEDs were emitting exclusively in blue so that the CRI was staying below 75. Also, some "warm" tints such as the 4000k ones have the same lumen output as 6000k LEDs, how ? There is much phosphor on warmer LEDs so the output should be lower right ?

2. The binning "grade" of the LEDs impact the CRI. If you want a high binning grade, such as P2, CRI is 70+. Consequently, a high CRI means a low binning, why ?

That's a lot of questions but maybe I'm not the only one interested by the answers ? Thanks !

Click to expand...

1.) Cool tinted LED's have more blue, but can still achieve a high CRI if the other shades are present at high enough levels to be a decent representation of an ideal source. It is in some cases easier to achieve high CRI at lower CCT's due to the additional phosphors, but varying the mix of materials in the phosphors helps. Nichia, for example, uses phosphors with two different main peaks to help them get better light.

Lower CCT LED's tend to be lower output both due to the increased amount of phosphor needed, and due to the lower sensitivity of the human eye to the orange and red tones that make up more of the lower CCT spectrum than of the high CCT spectrum.

2.) Emitters can be binned in different ways, such as output and color temperature. P2 is an output bin - Cree sells emitters that can achieve at least 1830 lumens at 12V and 1050mA as P2 binned. Because achieving high CRI reduces output, you only see that bin in the lower CRI emitters.