Basic led technologydick

LED BasicsLED BasicsDick Hintze

Pn DIODEPn DIODE

Light Emitting DiodesLight Emitting DiodesLight Emitting Diodes

(LEDs) are plastic capsules containing a specific chemical compound on a microscopic wafer that emits light when subjected to an electrical current.

Light Emitting Diodes (cont.)Light Emitting Diodes (cont.) Individual LEDs are available in many grades of

quality and shades of color. When red, green and blue LEDs are clustered

together and shine at their full brightness, the combined light emission appears white to the human eye. Varying the intensity of the three colors creates all the other shades.

Amber LEDs are used for monochrome displays.

PixelPixel

A single cluster of LEDs is used as a pixel.A pixel is a picture element; the smallest

individual unit or piece of a video display image. A pixel is an individual dot in a video display.

Each pixel has its own color and brightness attributes.

PitchPitch A display’s pitch is its measurement of distance from the

center of one pixel to the center of another pixel. The pitch determines the viewing distance. The smaller the

pitch, the shorter the viewing distance.

Pitch

Pitch

The angle off center at which the display output drops to half brightness. Expressed in degrees horizontal and vertical.◦ Ex: Horizontal 140° (±70°), and

vertical 60º (±30°).

Brightness rangeBrightness range

Electrical SpecificationElectrical Specification

RadiationRadiation

Brightness BinningBrightness Binning

Color BinningColor Binning

Color TemperatureColor Temperature Measured in degrees

Kelvin, color temperature is an indication of the amount of “warmth” (yellow, red tones) or “coolness” (blue tones) in a white light.

Standard video color temperature is 6500ºK.

Barco’s color temperature is adjustable.

Life ExpectancyLife Expectancy Old LEDs never die, they just fade away. The life expectancy represents the time passed before

the LED fades to half brightness. LEDs fade at a significantly faster rate after half brightness.