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Led disclaimer, Led life, Led binning – ILUMINARC Ilumipod™ 7 IP User Manual

Page 22: Color rendering index (cri), Technical information

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Technical Information

18

Ilumipod 7 IP Optic RGBW User Manual (Rev. 4)

LED Disclaimer

LED Life

ILUMINARC

®

rates LED lifetime based on lumen depreciation of 70% of the original

output, with data provided by the manufacturer of the LED. Data from the
manufacturer of the LED are not independently verified or measured by
ILUMINARC

®

. When the product is operating in optimal environmental conditions,

the LED lifetime is rated to be 50,000 to 70,000 hours by the LED manufacturer.

LED Binning

LED manufacturers sort LEDs into “bins”, based on variances in color, output
intensity and the frequency at which the semiconductor operates. ILUMINARC

®

strives to hold its LED manufacturers to the highest standards of binning to optimize
consistency in output from product to product. However, the availability of a single bin
cannot be guaranteed. With that in mind, ILUMINARC

®

has developed a rigorous

control system to seek the best achievable consistency in color and output.

Color Rendering Index (CRI)

CRI is an industry standard method to compare properties of different types of light
sources. There are known limitations and inconsistencies related to CRI. Results may
vary depending on the environmental factors involved. For this reason, the US
Department of Energy (DOE) states that CRI should be considered as one point of
reference among others in evaluating white LED products and systems.

The following is an excerpt of recommendations from the DOE:

1. Identify the visual tasks to be performed under the light source. If color fidelity

under different light sources is critically important (for example, in a space where
color or fabric comparisons are made under both daylight and electric lighting),
CRI values may be a useful metric for rating LED products.

2. CRI may be compared only for light sources of equal CCT. This applies to all

light sources, not only to LEDs. Also, differences in CRI values of less than five
points are not significant, e.g., light sources with 80 and 84 CRI are essentially the
same.

3. If color appearance is more important than color fidelity, do not exclude white

light LEDs solely on the basis of relatively low CRI values. Some LED products
with CRIs as low as 25 still produce visually pleasing white light.

4. Evaluate LED systems in person and, if possible, on-site when color fidelity or

color appearance are important issues.

Source: DOE publication: PNNL-SA-56891, January 2008