I do not understand bins, cri's and the other lingo. I am a network specialist and have worked in electronics on and off for years.
Thanks for your input![emoji6]
I'm bored tonight so I will take a swing at it. This is from Wikipedia:
A color rendering index (CRI) is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source. Light sources with a high CRI are desirable in color-critical applications such as neonatal care, photography and cinematography.
As we tend to use it here, the ideal light source is considered to be incandescent. We recognize that there is some variation amongst incandescent lamps, but it is considered insignificant to the discussion.We use it here to measure how close a given LED comes to rendering colors compared to the Holy Incandescent. The big thing to remember is that CRI is not a measurement that stands alone. One LED with a CRI of 85 may at a neutral color temp may actually do a better job of rendering colors than another LED with a CRI of 92 at a warmer color temp. [I am not going to try to explain color temperature - Wikipedia does a great job, with examples.]
And now for bins. Incandescents emit light across most of the visible spectrum, with a bias towards the warmer color temperatures. LEDs, on the other hand, actually emit light in a narrower band, which may actually be part or all Ultraviolet. Manufacturers add phosphors that will take the actual emitted light as input, and glow at a different color temp as output, usually in the visible spectrum. The available phosphors that do this only emit light on a few bands, and not across the entire spectrum. The challenge is to blend these phosphors to give the best representation of full spectrum light, and thus a high CRI. For an example, go to the Cree website and look at a datasheet for one of the popular LEDs like the XM-L. Cree gives a great spectral response graph showing how this looks.
All of the manufacturers measure the total spectral output of their LEDs, and assign them to a bin that corresponds to their primary color balance. This a single LED like the XM-L can have up to a dozen or more bins, depending on how well the various phosphors blended on that particular emitter. Thus you will see bin names like XM-L S4 or T5 or U2. Each bin will have a unique color temp, efficiency, and lumen output at a reference current. It can get very confusing, but a good rule of thumb is the higher the letter the higher the relative color temp and lumen output, with the numbers being subsets within the group.
As always, anyone who knows better, please feel free to correct my feeble attempts at explanation.
Now I'm tired so I'm going to bed.
