Glossary

Blackbody line (blackbody locus)

The blackbody line, when plotted on a CIE chart, represents the chromaticities of a material, heated to incandescence.

CCT (Correlated Color Temperature)

The CCT of a light source is the temperature at which an ideal black-body radiator gives off light. The temperature is reported in units Kelvin, with higher color temperatures such as 5,000K corresponding to cooler (bluish) colors, while lower color temperatures such as 2,700K correspond to warm (reddish) colors.

CE (Conversion Efficacy)

Conversion efficacy is the luminous flux (white light) output per radiant watt of blue light input. Conversion efficacy is rated based on reference operation and dominant blue LED wavelength at a specific temperature.

Class A

Class A is a designation for lighting color that scores high in tint perception, CCT and CRI. Class A color will have the following three attributes: chromaticity on or near the proposed line of minimum tint, which is not the same as the blackbody locus; good color rendering, defined by a CRI greater than 80 and a high (but not too high) gamut area index (80<GAI<100); and consistency in tint as defined by proposed tolerance zones of chromaticity. - "Class A Color for White Lighting, " Lighting Research Center. 2013.

CRI (Color Rendering Index)

CRI is a measurement that was originally created to help indicate how colors appear under different light sources. The closer the CRI is to 100, the better the artificial light source reproduces the colors of objects faithfully in comparison to the sun on a beautiful day. Despite its limitations, CRI is the only internationally agreed upon color rendering system. New measurement standards are in development to address some of the concerns about using CRI.

CSP (Chip Scale Package)

A chip scale package LED is a device where the complete surface mountable component is only marginally larger or the same size as the chip itself. With smaller source size and less materials, such designs enable more efficient and lower cost lighting systems.

Dominant Wavelength

Dominant wavelength is the color perceived. The human eye takes in all of the wavelengths emitted by the LED and perceives a dominant "color." This color is an amalgamation of all emitted colors, it will not directly correspond to the peak wavelength.

FWHM (Full Width Half Maximum)

FWHM is the distance between points on a spectral curve at which the function reaches half its maximum value.

GAI (Gamut Area Index)

The gamut area of a light source is that area enclosed by a polygon within a chromaticity diagram. The greater the separation among the selected points, the greater the gamut area. Generally, the greater the gamut area, the greater the perceived saturation of hues and the better the discrimination among hues under that source of illumination. Values of GAI can be higher than 100. - A practical and predictive two-metric system for characterizing the color rendering properties of light sources used for architectural applications, " Mark S. Rea, Lighting Research Center. Copyright 2010 SPIE.

LED (Light Emitting Diode)

LEDs are solid state light sources comprised of an integrated circuit using semiconductor technology. Historically, they have been used in electronic devices as red indicator lights on electronic interfaces. Advances in the early 1990s inspired researchers to pursue the dream of developing white solid state general lighting solutions. Modern LEDs now come in a variety of shapes, sizes and colors, often relying on phosphor powders to produce very specific colors.

LED lights are highly efficient, using less energy and generating less heat than traditional incandescent or fluorescent bulbs, while yielding excellent brightness and light quality. Typical lifetimes for solid state lights are 25,000 - 100,000 hours, compared to 1,200 - 20,000 hours for compact fluorescent lamps (CFLs) and around 1,000 hours for AC incandescent lamps.

Lumen (lm)

A lumen is a unit of measure of the power of light perceived by the human eye. It is the unit to look for when measuring the differences in available light between two distinct light sources.

Luminous Efficacy (Lm/W)

A quantitative measure of performance from light sources, calculated as lumens (lm) per watt (W). The higher the luminous efficacy, the better the energy efficiency of the light source. An incandescent light bulb might have a luminous efficacy of 14 lm/W while LEDs have been demonstrated to have efficacies as high as 200 lm/W in research labs.

Mixing Chamber

The mixing chamber is an important element in LED remote phosphor architectures. The chamber consists of the space between the blue LED and the remote phosphor component. The purpose of the mixing chamber is to efficiently combine and reflect down-converted light to maximize efficacy of the overall system.

Peak Wavelength

Peak wavelength is the wavelength of highest intensity in the spectral distribution.

Phosphors

Phosphors are materials that absorb light and convert it into a broad range of other lower energy wavelengths of light. For example, Intematix phosphors are coated over blue LED chips or integrated as ChromaLit remote phosphor, and, depending on the precisely controlled color selected by Intematix's proprietary family of phosphor materials, consistent, high quality white light of varying color temperatures and CRIs shines out of the device.

QD (Quantum Dots)

Quantum dots are very small particles made of semiconductor on the nanometer scale. Some formulations of quantum dots are luminescent and can be integrated into LED components and lighting systems.

R9

R9 is the red sample color rendering, measurement up to 100. While CRI only measures R1-8, R9 is an additional measurement for light quality.

Remote Phosphor

Remote phosphor describes an approach to lighting which separates phosphor from the source of photons that excite it. In a conventional white LED system, phosphor is deposited directly on a blue LED chip, but remote phosphor architectures leverages a phosphor composite integrated with a remotely located substrate. This architecture provides unparalleled design freedom, more efficient manufacturing processes, exceptional light quality and up to 30 percent higher system efficacy.  After years of research and development on remote phosphor technology in tandem with phosphor development, Intematix launched ChromaLit remote phosphor light sources in January 2011.

SDCM (Standard Deviation Color Matching)

SDCM has the same meaning as a "MacAdam ellipse." A 1-step MacAdam ellipse defines a zone in the CIE 1931 2 deg (xy) color space within which the human eye cannot discern color difference. Most LEDs are binned at the 4-7 step level, in other words you certainly can see color differences in LEDs that are ostensibly the same color. - "Taking Photometry: LED Colour Difference Metrics: SDCM & MacAdam Ellipses," Photometric & Optical Testing. www.photometrictesting.co.uk.

Semiconductor

A semiconducting material is one that can transport an electric current, and has an electrical conductivity between that of a conductor and an insulator. Devices made from semiconductor materials are the foundation of modern electronics, including computers and telephones. Examples of semiconductor devices include tiny light-emitting diodes (LEDs), wherein the semiconductor is the die chip, and solar photovoltaic panels.

Watt (W) - Electrical

Watts are a unit of measure that describe how much power a device requires to function. For example, a typical incandescent bulb might consume 100 Ws. A typical LED, on the other hand, might only require 20W to give off the same amount of lumens.

Watt (Wrad) - Optical

Wrad is the radiometric power measured in watts.

Wavelength of Light

Wavelength is another way to describe the color of light along the complete electromagnetic spectrum. Human eyes can see only a limited slice of the full electromagnetic spectrum, and this "visible light" ranges in wavelengths between 400 - 700 nanometers (nm). The visible colors from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red.

WPE (Wall Plug Efficiency)

WPE or radiant efficiency is the energy conversion efficiency with which the system converts electrical power into optical power.