A
Accent Lighting
Directional lighting to emphasize a particular object or draw attention to a
display item.

Adaptation
The process by which the human eye adjusts to a change in light level.

Ambient Lighting
The general lighting present in an area --excluding task lighting and accent lighting but including general lighting and daylight streaming in.

Ambient Temperature
The surrounding temperature within an environment.

Amperes
("Amps.") A measure of electrical current. In LED lights, the current is related to voltage and power as follows: Watts (power) = Volts x Amps (current).

B
Backlit sign
A sign where the sign face is illuminated from behind. (Also called illuminated sign. See also internally illuminated sign and exterior illuminated sign.)

Brightness
Brightness can refer to any of several technical terms used in lighting and is, therefore, ambiguous (See LUMINANCE ).

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C
Canadian Standards Association (CSA)
An organization that writes standards and tests lighting equipment for performance as well as electrical and fire safety. Canadian provincial laws generally require that all products sold for consumer use in Canada must have CSA or equivalent approval.

Candela (cd)
The measure of luminous intensity of a source in a given direction. The term has been retained from the early days of lighting when a standard candle of a fixed size and composition was defined as producing one candela in every direction.

Chip
A very small square of semi-conducting material. Also known as a "die," it is the "active" light-emitting component of an LED.

Chromaticity
Measure to identify the color of a light source, typically expressed as (x,y) coordinates on a chromaticity chart (See COLOR TEMPERATURE).

Color (Dominant Wavelength)
LEDs are designed to give off a specific color emission. The dominant wavelength is a quantitative measure of an LED color as perceived by the human eye and is usually measured in nanometers (a billionth of a meter). In order to specify an LED, you must specify the color or dominant wavelength range required for your application. Some applications may have color constraints in order to meet specific government specifications or regulatory guidelines.

Color Bin
LEDs are sorted according to their wavelength or CIE coordinates into different groupings or "bins."

Color Temperature (Correlated Color Temperature - CCT)
A number indicating the degree of "yellowness" or "blueness" of a white light source. Measured in Kelvin’s, CCT represents the temperature an incandescent object (like a filament) must reach to mimic the color of the lamp. Yellowish-white ("warm") sources, like incandescent lamps , have lower color temperatures in the 2700K-3000K range; white and bluish-white ("cool") sources, such as cool white (4100K) and natural daylight (6000K), have higher color temperatures. The higher the color temperature the whiter, or bluer, the light will be (See CHROMATICITY).

Constant Current Technology (CCT)
Constant Current Technology (CCT), the heart of the SloanLED Line. CCT is the design backbone of the ChanneLED, ThinLED, FlexiBRITE and ColorLINE systems. CCT maintains consistent current levels, eliminating the line loss and voltage drop issues common in many LED lighting systems. CCT provides uniform light output throughout the entire installation, while also preventing damage from overdriving of the LEDs.

Cool Colors
Refers to cool colors in the light spectrum – whites, blue, and green

Cool White
A term loosely used to denote a color temperature of around 6500 K.

Cost of Light
Usually refers to the cost of operating and maintaining a lighting system on an ongoing basis. The 88-8-4 rule states that (typically) 88% is the cost of electricity, 8% is labor and only 4% is the cost of lamps.

Current Type (AC/DC)
Whether the operational voltage is based on Alternating Current or Direct Current.

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D
Dimmable
Whether or not the lamp lumens can be varied while maintaining reliability.

Dimmer, Dimming Control
A device used to lower the light output of a source, usually by reducing the wattage it is being operated at. Dimming controls are increasing in popularity as energy conserving devices.

Dominant Wavelength
A quantitative measure of the color of an LED as perceived by the human eye. It is usually measured in nanometers (a billionth of a meter).

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E
Efficacy
A measurement of how effective the light source is in converting electrical energy to LUMENS of visible light. Expressed in LUMENS-PER-WATT (LPW) this measure gives more weight to the yellow region of the spectrum and less weight to the blue and red region where the eye is not as sensitive.

Efficiency
The efficiency of a light source is simply the fraction of electrical energy converted to light, i.e. watts of visible light produced for each watt of electrical power with no concern about the wavelength where the energy is being radiated.

Epoxy
Organic polymer frequently used for a dome or lens, often prone to optical decay over time, resulting in poor lumen maintenance.

Eye Sensitivity
A curve depicting the sensitivity of the human eye as a function of wavelength (or color). The peak of human eye sensitivity is in the yellow-green region of the spectrum. The normal curve refers to photopic vision or the response of the cones.

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F
Federal Communications Commission (FCC)
The U. S. Federal agency that regulates emissions in the radio frequency portion of the electromagnetic spectrum. Part 18 of the FCC rules specifies electromagnetic interference (EMI) from lighting devices operating at frequencies greater than 9 kilohertz (kHz).

Flicker
The periodic variation in light level caused by AC operation that can lead to strobe effects.

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

Footcandle (fc)
A unit of illuminance or light falling onto a surface. It stands for the light level on a surface one foot from a standard candle. One foot-candle is equal to one lumen per square foot. See also Lux.

Foot-candle Meter
(See ILLUMINANCE METER).

Foot-lambert
An obsolete term referring to a luminance of 1/? Candelas per square foot.

Forward Current
Current through a diode in the direction of its greatest conduction.

Forward Voltage (VF)
The voltage across a diode for a given forward current.

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G

H

I
Illuminance
The "density" of light (lumens/area) incident on a surface; i.e. the light level on a surface. Illuminance is measured in foot-candles or lux.

Indirect Lighting
The method of lighting a space by directing the light from luminaires upwards towards the ceiling. The light scattered off the ceiling produces a soft, diffuse illumination for the entire area.

Intensity Bin
LEDs are sorted according to their intensity values into different groupings or "bins."

Inverse Square Law
Formula stating that if you double the distance from the light source, the light level goes down by a factor of 4, if you triple the distance, it goes down by a factor of 9, and so on.

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J


K
Kelvin Temperature
Term and symbol (K) used to indicate the comparative color appearance of a light source when compared to a theoretical blackbody.

Kerning:
The act of moving letters further apart or closer together in order to achieve a desired effect.

Kilowatt (kW)
The measure of electrical power equal to 1000 watts.

Kilowatt Hour (kWh)
The standard measure of electrical energy and the typical billing unit used by electrical utilities for electricity use. A 100-watt lamp operated for 10 hours consumes 1000 watt-hours (100 x 10) or one kilowatt-hour. If the utility charges $.10/kWh, then the electricity cost for the 10 hours of operation would be 10 cents (1 x $.10)

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L
Leadframe
A metallic frame used for mounting and connecting LED chips. The leadframe functions as the electrical leads of the device.

LED
A Light Emitting Diode (LED) is a solid-state semiconductor device that converts electrical energy
directly into light.

Lens
A transparent or semi-transparent element which controls the distribution of light by redirecting individual rays. Luminaires often have lenses in addition to reflectors.

Light
Radiant energy that can be sensed or seen by the human eye. Visible light is measured in lumens.

Light Meter
A device that measures the illuminance at a location calibrated either in foot-candles or in lux.

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.

Lumen Maintenance
A measure of how well a lamp maintains its light output over time. It may be expressed numerically or as a graph of light output vs. time.

Luminance
A measure of "surface brightness" when an observer is looking in the direction of the surface. It is measured in candelas per square meter (or per square foot) and was formerly referred to as "photometric brightness."

Luminous Efficacy
(See EFFICACY)

Luminous Intensity
A measure of the visibility of a light source generally expressed in candelas. It is defined as luminous flux per unit solid angle (steradian) in a given direction.

Lux (lx)
A unit of illuminance or light falling onto a surface. One lux is equal to one lumen per square meter. Ten lux approximately equals one foot-candle. (See FOOT-CANDLE)

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M
Monument Sign:
A freestanding sign that stands directly on the ground or ground level foundation. A monument sign is often used to mark a place of significance or the entrance to a location.

N
Nits - Measurement of display screen brightness. 1 nit = 1 cd/m2. The more nits, the brighter the picture.

O
Open channel letter
A channel letter with returns that project forward from face of letter such that the neon tubing is visible.

P
Pantone Matching System (PMS)
A standardized color scheme used in the printing industry to ensure the consistency of color from design to final print.

Peak Wavelength
The maximum wavelength of an LED.

Phosphor
An inorganic chemical compound processed into a powder and deposited on the inner glass surface of fluorescent tubes and some mercury and metal-halide lamp bulbs. Phosphors are designed to absorb short wavelength ultraviolet radiation and to transform and emit it as visible light (See FLOURESCENCE).

Photometry
The measurement of light and related quantities.

point of purchase (POP) sign
In-store advertising designed to stimulate impulse purchases by shoppers inside a store. Also known as "point-of-sale advertising".

Pylon sign
A freestanding sign that is not a pole or ground sign.

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Q

R
Raceway
It is an enclosed conduit that forms a physical pathway for electrical wiring. Channel Letters are mounted to the front of the Raceway. It protects wires and cables from heat, humidity, corrosion, water intrusion and general physical threats. The raceway itself is attached to the wall with lag bolts, through bolts or toggle bolts, depending on your type of wall.

Reverse channel letter
A channel letter that has a face and sides but no back, and is pinned out from a background surface. When the neon tube inside the letter is illuminated, it produces a halo effect around the letter.

Return
The sides of a channel letter

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S
Sans Serif
Any typeface that lacks serifs. Helvetica and Futura are familiar sans serif fonts.

Serif:
A small line or embellishment finishing off the strokes of letters in some fonts. Well-known serif fonts include Souvenir, Times New Roman and Garamond.

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.

Stroke Width:
The width of the lines comprising a letterform.

Substrate
The material out of which the face is made. Wood, metal sheeting, paper and acrylic are some examples of sign substrates.

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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.

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U
Underwriters Laboratories (UL)
A private organization which tests and lists electrical (and other) equipment for electrical and fire safety according to recognized UL and other standards. A UL listing is not an indication of overall performance.

V
Viewing Angle
The maximum angle at which a display can be viewed with acceptable visual performance.

Volt
A measure of "electrical pressure" between two points. The higher the voltage, the more current will be pushed through a resistor connected across the points.

Voltage
A measurement of the electromotive force in an electrical circuit or device expressed in volts. Voltage can be thought of as being analogous to the pressure in a waterline.

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W
Warm Colors
Refers to the warmer colors in the light spectrum – red, orange and yellow.

Warm White
Refers to a color temperature around 3000K, providing a yellowish-white light.

Watt
A unit of electrical power. Lamps are rated in watts to indicate the rate at which they consume energy (See KILOWATT HOUR).

Wavelength
The distance between two neighboring crests of a traveling wave. The wavelength of light is between 400 and 700 nanometers. 

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X

Y 

Z

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