Technology Glossary
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A
Adobe RGB
The RGB (Red, Green, Blue) colors created by Adobe Systems providing a large gamut of colors that is well suited for printing CMYK (Cyan, Magenta, Yellow, Black) documents.
AllnGaP
The preferred LED (Light Emitting Diode) chip technology containing Aluminum, Indium, Gallium, and Phosphorous to produce red, orange and amber-colors.

B
Beam angle
The angle between two imaginary lines in a plane through the optical beam axis, such that these lines pass through the centre of the front face of the lamp and through points at which the luminous intensity is 50% of the centre beam intensity.
Bin
The systematic dividing of distribution of performance parameters (Flux, Color or CCT, and Vf) in to smaller groups that meet aesthetic requirements of the assembly. Although the word "bin" is the preferred term, sometimes one will find the word "rank" in use.
Binning
Subdivision of the manufactured distribution into bins common operating parts (color, flux, forward voltage).

C
Candela (cd)
The luminous intensity as defined by the international metric standard (SI). The term, retained from the early days of lighting, defines a standard candle of a fixed size and composition as a basis for evaluating the intensity of other light sources.
CCFL
Cold Cathode Fluorescent Lighting: Often used as a backlight for LCD displays and usually containing Mercury (Hg) or other regulated heavy metals.
Center beam intensity
The value of the luminous intensity measured on the optical beam axis.
CIE Chromaticity Diagram
International Commission on Illumination. A horseshoe shaped line connecting the chromaticities of the spectrum of colors. (See Color Definition, Chroma).
CISPR
Comité International Spécial des Perturbations Radioélectriques.
Correlated Colour Temperature (CCT)
The temperature of the Planckian radiator whose perceived colour most closely resembles that of a given stimulus at the same brightness and under specified viewing conditions.
Color Definition

The color of uniformly illuminated objects described using three terms:

Hue: Describes the situation when the appearance of different colors is similar (e.g. matching blues and pinks).

Lightness: Describes a range of grayness between black and white.

Chroma: Describes the degree of departure from gray of the same lightness and increasing color (e.g. red, redder, pure red).

Color gamut
The range of colors within the CIE Chromaticity Diagram included when combining different sources.
Color spectrum
All wavelengths perceived by human sight, usually measured in nanometers (nm).
Color temperature
The description used to describe the effect of heating an object until it glows incandescently, the emitted radiation, and apparent color, changes proportional to the temperature; easily envisioned when considering hot metal in a forge that glows red, then orange, and then white as the temperature increases.
Conformal Phosphor Coating
Patented process that uniformly coats the LED with phosphor. This eliminates the blue-ring effect common to other white LEDs and delivers the consistent white color throughout the light beam.
Cool White
A description of light with a correlated color temperature between 5000K and 7500K, usually perceived a slightly blue.
Correlated Color Temperature (CCT)
The phrase use to describe the temperature at which a Planckian Black Body Radiator and an illumination source,s appear to match, usually specified in Kelvin (K).
CRI or Color Rendering Index
The calculated rendered color of an object. The higher the CRI (based upon a 0-100 scale), the more natural the colors appear. Natural outdoor light has a CRI of 100. Common lighting sources have a large range of CRI.

D
Die
Chip: heart of the LED
Diffuser
An optical element used to mix light rays to improve uniformity.
Directional lamp
A lamp having at least 80% of light output within a solidangle of p sr (corresponding to a cone with angle of 120degree).
Driver
Electronics used to power illumination sources. Ballast.
Duv
The closest distance from the Planckian locus on the (u’,2/3 v’) diagram, with + sign for above and – sign for below thePlanckian locus.

E
Efficacy
(Luminous Efficacy) - The light output of a light source divided by the total electrical power input to that source, expressed in lumens per watt (lm/W).
Epoxy
Organic polymer frequently used for a dome or lens, often prone to optical decay over time, resulting in poor lumen maintenance.

F
Flux
The sum of all the lumens (lm) emitted by a source (see lumen).

I
IEC
International Electrotechnical Commission.
IES
Illuminating Engineering Society of North America.
InGaN LED
The preferred LED (Light Emitting Diode) semiconductor technology containing Indium, Gallium, and Nitrogen to produce green, blue and white-colored LED light sources.
Initial value
A photometric and electrical characteristics at the end ofthe stabilization time.

K
Kelvin Temperature
Term and symbol (K) used to indicate the comparative color appearance of a light source when compared to a theoretical blackbody. Yellowish incandescent lamps are 3000K. Fluorescent light sources range from 3000K to 7500K and higher.

L
LED
A Light Emitting Diode (LED) is a solid-state semiconductor device that converts electrical energy directly into light. On its most basic level, the semiconductor is comprised of two regions. The p-region contains positive electrical charges while the n-region contains negative electrical charges. When voltage is applied and current begins to flow, the electrons move across the n region into the p region. The process of an electron moving through the p-n junction releases energy. The dispersion of this energy produces photons with visible wavelengths.
LED driver
A power source with integral Light Emitting Diode (LED)control circuitry designed to meet the specific requirements of aLED lamp or a LED array.
LED lamp
A lamp, incorporating a Light Emitting Diode (LED) lightsource and any additional elements necessary for stableoperation of the light source, provided with a lamp cap
conforming IEC 60061-1, which cannot be dismantled withoutpermanent damages.
LED lamp, integral
A Light Emitting Diode (LED) lamp intended to operatedirectly on mains voltage.
LED lamp, nonintegral
A Light Emitting Diode (LED) lamp intended forconnection to an LED driver and cannot be operated directly onmains voltage.
Lumen (lm)
The international (SI) unit of luminous flux or quantity of light and equals the amount of light that is spread over a square foot of surface by one candle power when all parts of the surface are exactly one foot from the light source. For example, a dinner candle provides about 12 lumens. A 60-Watt Soft White incandescent lamp provides 840 lumens.
Luminous efficacy(lm/W)
A ratio of luminous flux emitted by a lamp to theelectrical power consumed by the lamp.
Luminous flux (lm)
A quantitative measure of light emitted by a light source.The quantity is derived from radiant flux (power in Watt) byevaluating the radiation in accordance with the spectral
sensitivity of the standard eye as described by the CIE StandardPhotometric Observer.
Luminous intensity(cd)
The quotient of the luminous flux dFv leaving the sourceand propagated in the element of solid angle dW containing thegiven direction, by the element of solid angle
non-directional lamp means a lamp that is not a “directional lamp”.
Lumen maintenance
The remaining flux percentage at the rated life of a light source.A luminous flux at a given time in the life of a LED-lampdivided by the initial value of the luminous flux of the lamp andexpressed as a percentage of the initial luminous flux.
Lumen Maintenance Curve
A graph comparing the loss of light output against the time the light source is used.
Luminaire
A lighting fixture complete with installed lamps and other accessories.
Lux (lx)
The SI (International) unit of illuminance, or luminous flux incident on a unit area, frequently defined as one lumen per square meter (lm/m2).

N
Metameric
The term used to describe the visual perception phenomenon where spectrally different sources blend into a third chroma. For example, Sir Isaac Newton discovered that people perceive white when observing mixed blue and yellow light.

N
Nits
Measurement of display screen brightness. 1 nit = 1 cd/m2. The more nits, the brighter the picture.
NTSC color space
The range of colors within the CIE Chromaticity Diagram included when combining phosphor based RGB sources in CRTs such a televisions and computer monitors.

O
Optic
A device that changes the direction of a ray of visible light, usually by reflection, such as a mirror, or refraction by a lens.
Optical beam axis
The axis about which the luminous intensity distribution is substantially symmetrical.

P
P-N Junction
Area on an LED chip where the positively and negatively charged regions meet. When voltage is applied and current begins to flow, the electrons move across the n region into the p region. The process of an electron moving through the p-n junction releases energy. The dispersion of this energy produces photons with visible wavelengths. In short, the area on a chip where light is produced.
Planckian Black Body Locus
The line on the CIE Chromaticity Diagram that describes the color temperature of an object when heated from approximately 1,000K to more than 10,000K.
Power factor
a ratio of the measured active input power to the product of the supply voltage (r.m.s.) and the supply current (r.m.s.).

S
Solid-state lighting
A description of the devices that do not contain moving parts or parts that can break, rupture, shatter, leak or contaminate the environment.

S
Solid-state lighting
A description of the devices that do not contain moving parts or parts that can break, rupture, shatter, leak or contaminate the environment.
Stabilization time
The time which the LED lamp requires to obtain stable thermal conditions
sRGB
A Standard Default Color Space for the Internet created by Hewlett-Packard and Microsoft to support a standard color space within the Microsoft operating systems, HP products, and others.

T
Thermal management
Controlling the operating temperature of the product through design, examples includes heat sinks and improved airflow.
Thermal resistance (C/W)
A measure of the heat transfer capacity of the LED. Lower resistance is preferred.

V
Volt
The term used to describe the electrical potential difference between oppositely charged conductors, for example there is a 1.5V potential between the top and bottom of a battery.

W
Warm White
A description of light with a correlated color temperature between 3000K and 3500K, usually perceived a slightly yellow.
Watt
The unit of electrical power as used by an electrical device during its operation. Many lamps come with rating in watts to indicate their power consumption. A light source with a higher lumen per watt value is more efficient.
White point
The Coordinated Color Temperature (CCT) defined by a line perpendicular to the Planckian Black Body Curve and intersecting the measured chromaticity.