Glossary

 

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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.
Ampere (Amp)
The unit for measuring rate of flow of electrical current: Current (Amps) = Power (Watts) / Voltage (Volts)

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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).

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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.
CIE Chromaticity Diagram
A horseshoe shaped line connecting the chromaticities of the spectrum of colors. (See Color Definition, Chroma).
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 as 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.

For example:

  • Cool White CRI = 62
  • LUXEON CRI = 70
  • Vita-Lite CRI = 91

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Die
Chip: heart of the LED
Diffuser
An optical element used to mix light rays to improve uniformity.
Discrete LEDs
Flat panels that are suspended or recessed, not surface-mounted.
DIY
Do-it-yourself (as in, "Mounts for Pixi Flatlights™ are DIY")
Driver
Electronics used to power illumination sources. Ballast.

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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).
Electroluminescence
EL is an optical phenomenon and electrical phenomenon in which a material emits light in response to the pass of an electric current or to a strong magnetic field.
Epoxy
Organic polymer frequently used for a dome or lens, often prone to optical decay over time, resulting in poor lumen maintenance. Luxeon power light sources contain no epoxy and deliver superior lumen maintenance.

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

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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.

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K

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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.

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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.

Levels:

  • Level 1 — The chip or die
  • Level 2 — The LED component
  • Level 3 — LED array; may include optics, heat sink and/or power supply
  • Level 4 — LED luminaire
LED Panels
Thin, energy-efficient lights that utilize light-emitting diodes. They are placed on walls, ceilings, under counters and other areas. They last for 50,000 hours or more. Pixi FlatLights™ are available in Residential and Commercial-Grade designs. Hardwire Under-Cabinet Lighting — Hardwired under-cabinet lights are connected directly to a power source using standard household electrical wire.
Lumen (lm)
The international (SI) unit of luminous flux or quantity of light that 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.
Lumen maintenance
The remaining flux percentage at the rated life of a light source.
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).

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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.

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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.

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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.

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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.

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Recessed Lighting
A light fixture that is installed into a hollow opening in a ceiling, It concentrates light in a downward direction as a broad floodlight or narrow spotlight.

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SMD
Surface-mounted LED panels
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.
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.
Suspended Lighting
A light fixture that is dropped down and mounted beneath the surface of a ceiling or off a wall. Pixi FlatLight™ LEDs can be suspended in various ways and are available in both Residential and Commercial-Grade designs.

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T-Bar
Linear light bar fixtures that come in various lengths and sizes. Used to mount a series of ceiling lights. Usually constructed of extruded aluminum.
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.
Troffers
Long, recessed luminaire usually installed with the opening flush with the ceiling.

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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.

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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.

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