What is LED Binning?
Binning for LEDs is a quality assurance measure. The aim is to sort LEDs according to various quality criteria. One important factor here is the light color. With precise sorting, manufacturers ensure that the LEDs in a category are as homogeneous in quality as possible.
This avoids errors such as areas of light that do not appear uniform or points of light with different brightness. The more precise the LED binning, the higher the quality of light of the products.
As mentioned, there are various key figures for the definition of LED binning.
It is common to classify them according to the following criteria:
- Voltage Binning: Binning according to voltage is mainly important for the technical side. For manufacturers of solar lights, for example, it is relevant how high the voltage is that drops across each individual light emitting diode in order to optimize the product.
- Flux Binning: Flux refers to the luminous flux, which is measured in lumens. In simple terms, the metric shows how brightly an LED shines. Here it is also useful to sort the individual diodes according to equal strength in order to avoid glaring light points.
- Color Binning: Binning by light color and color value is most relevant for consumers. The process ensures that your panel lights, wall lights and the like emit a uniformly colored light and that no color differences are discernible. The background to this is that several light-emitting diodes are used for these designs. Without LED binning, it could happen that the luminaires emit visibly different colored light cones and thus the color impression is disturbed.
These binning areas exist
- Lumen: How brightly does an LED shine?
- Color temperature: This value is given in Kelvin (K).
- Voltage: What is the electrical voltage across the LED?
- Color location: How does the light appear (cold, warm, daylight white, etc.)?
Depending on the application, some areas are more important than others.
For example, for a desk lamp to provide pleasant light that increases concentration, color temperature and color locus are particularly relevant.
How does LED binning work?
The term "binning" is derived from English. "Bin" means something like "container" or "barrel". The explanation is simple: In fact, the individual LEDs are sorted by the manufacturers in bins according to their properties. The term LED binning has therefore become established for the categorization of LEDs. In practice, there are various measuring devices for this purpose. For example, a voltmeter measures the voltage, a photometer measures the wavelength.
But which LED goes into which container? In the meantime, there are uniform binning standards worldwide for this according to the ANSI standard. ANSI stands for the American Institute for Standards and Standardization. The Americans have determined guideline values according to which LEDs are sorted. Do you want to know more about it? More details can be found in the paragraph about MacAdams ellipses.
Why is LED binning
As a customer, you place the highest value on your luminaires looking elegant and classy - and on them illuminating the room as desired. Now imagine an LED strip that emits light with different colors along the way. That would be a disaster.
That's why manufacturers do LED binning. But why do LEDs differ in the first place? It's because of how the technology is manufactured. LED chips are made of special semiconductor crystals. These are doped with various elements and bonded together so that light is emitted when a voltage is applied. Sounds complicated, and it is - although production is now much simpler than it was at the beginning of the 21st century.
The fact is, however, that due to the high production challenges and micro-scale manufacturing, it happens that the individual products differ minimally from each other - even within one batch. Therefore, LED binning was developed to offer you LED downlights and co. in best quality.
A look at the details:
the CIE 1931 diagram
Working with LEDs is an interesting field, because on the one hand it is about technology, on the other hand it is about people. Surely you know this: light with a high blue content has a completely different effect than a luminaire with a yellow glow. That's why it makes a difference for the products whether the light appears cold or bright. LED ceiling lights for the study, for example, should produce a light that is perceived as daylight. That way, you'll stay awake longer and be more focused. With LED decorative lights, on the other hand, it is undesirable for them to shine garishly. Warm tones are the right choice here. What does this have to do with technology? Quite a lot.
To meet the requirements mentioned, a relation between human perception and physical measurands is necessary. This is exactly what the CIE 1931 diagram is for. It is a color system that encompasses visible light. The corner points are the colors red, green and blue, from which the RBG system is derived.
The so-called Planck curve is particularly interesting for the production of LEDs. For understanding more theory: A radiator, which is continuously heated, emits light along this curve depending on the temperature. This results in the classification of LEDs according to color temperature. Here there is a direct point of contact with the technology of incandescent lamps. If you are looking for an equivalent to your old 60 W incandescent lamp, you should choose a 2700 K LED.
LED Binning with MacAdams Ellipses
For LED binning, the CIE diagram has a special meaning. Suppose you want to sort LEDs by quality. Then it seems logical to define a color change around a reference color or color value. In this way, all LEDs that lie within a circle in the CIE diagram would be assumed to be of equal quality.
However, this does not work! David MacAdam found out that the distances in the CIE diagram do not correspond to the perception threshold of the human eye. Instead, the result is an elliptical shape. So LED binning is done using ellipses, not circles. More precisely: the MacAdams ellipses.
The definition of these ellipses has a direct influence on the quality. Here, the smaller they are, the more uniform the LEDs. Here, another quantity comes into play: the standard deviation of color matching, or SDCM for short. A deviation of one SDCM can almost not be distinguished by the eye. For LED binning, most manufacturers use a maximum tolerance of two SDCM.
Good to know: The deviation in SDCM must be specified by the manufacturers for the European market.
Avoiding color deviations at home
In addition to production-related color variations, other effects can occur with LEDs that lead to different color perceptions or varying luminous intensities. One of these is aging. After about 10,000 hours of operation, the brightness may start to diminish. Background: The LED emits less light, the measured value in ANSI lumens decreases. Likewise, color unevenness is sometimes observed after a long time. Such problems can be fixed quickly: simply replace the illuminant.
On the other hand, the described effects may be due to covers of the luminaire. If you have the impression that the light of your LED spotlight is unevenly strong or has an unusual hue, then it is best to check the panes or the covers on the luminaire. If in doubt, look directly at the lamp.
But be careful: Never look directly into the LEDs, the luminous flux is very high close to the source.
LED Binning and WATT24
After explaining LED binning, the question arises:
What does it have to do with WATT24?
We take care to offer you only high-quality products. This includes ensuring that LEDs for indoor and outdoor lighting emit uniform light. Therefore, you will find only products that have been sorted according to high standards of LED binning.