ANSI C78.377:2017 pdf download.Electric Lamps-Specifications for the Chromaticity of Solid-State Lighting Products.
The purpose of ANSI C78.377 is to specify the range of chromaticity for general lighting with solid-state lighting (SSL) products, as well as to ensure that the chromaticity of the products can be communicated to consumers. This standard applies to LED lamps, LED light engines and LED luminaires for general indoor lighting applications, and may apply more broadly.
This document does not apply to lighting fixtures sold without a light source. This standard also does not apply to SSL products for some indoor applications that intentionally produce colored light. This document does not include OLED products.
1.1 Patent Disclaimer
At the time of publication, it is possible that some of the elements of this document may be the subject of patent rights. When this Standard was approved for publication, the Accredited Standards Committee C78 and the National Electrical Manufacturers Association (NEMA) did not know of any patent
applications, patents pending, or existing patents. ASC C78 shall not be held responsible for identifying any or all such patent rights.
2 Normative References
All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
CIE 15: 2004, Commission Internationale de l’Eclairage, Colorimetry, 3rd Edition ANSI/IES RP-1 6-10, Nomenclature and Definitions for Illuminating Engineering IES LM-79-08, Illuminating Engineering Society of North America, Approved Method for the Electrical and Photometric Measurements of Solid-State Lighting Products
3 Definitions
Terms used in this document such as LED lamp and LED luminaire are defined in ANSI/IES RP-16-10.
4 Chromaticity
4.1 Basis
The chromaticity coordinates and correlated color temperature (CCT) values used in this standard are based on the CIE colorimetry system. While the chromaticity of light is expressed by chromaticity coordinates such as (x, y) and (u’, v) the chromaticity of nominally white light can also be expressed by CCT and the distance from the Planckian locus. CCT is a more intuitive measure of the shade of white light than (x, y) or (u’, v). Since COT is defined based on the (u’, 2/3v) chromaticity diagram, the distance from the Planckian locus should be determined on the same diagram. It should be expressed as a signed value to indicate whether the chromaticity is above or below the Planckian locus. As such a distance parameter with respect to the Planckian locus is not officially defined by the CIE, “Duv” (symbol: D) is defined in this document as the closest distance from the Planckian locus on the (u’, 2/3v) diagram, with “÷“ sign for above and “—“ sign for below the Planckian locus.
4.2 Nominal CCT and Target CCT
Nominal CCT is used to specify and communicate chromaticity information of a product, and, in this document, is a CCT value at 100 K steps that is closest to the target CCT of the product. A target CCT is the CCT value that the product is designed to produce. Individual samples of the product may deviate from the target CCT due to production variation, which is normally controlled to be within a production tolerance. The same applies to target Duv. The target CCT and target Duv are also the center points of the tolerance range of these parameters in this document.
4.3 Specifications
SSL products included in this standard shall have chromaticity values that fall into one of the nominal CCT categories listed in Table 1 or Table 2. SSL products with a given nominal CCT shall have the defined target CCT and Duv, and the values of individual samples shall be within the tolerances of CCT and Duv as listed in Table 1 or Table 2. Measurement of chromaticity shall be made in accordance with methods given in the measurement standard IES LM-79-08.ANSI C78.377
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