Here are some valuable definitions that will help you during your LED Shopping experience.
LED (Light-Emitting Diode)
A light-emitting diode (LED) is a two-lead semiconductor light source that illuminates when electricity passes through it. When ample voltage (electricity) is applied to the leads, electrons recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the energy band gap of the semiconductor.
LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, and lighted wallpaper.
Industry standard LEDs are rated at 100,000 (11+ years) of constant use.
Pixel (Picture Element)
The word pixel is based on a contraction of pix (short for “pictures”) and el (for “element”).
A pixel is a point of light. A LED display is made up of an array of pixels, multiple points of light appearing as dots. A pixel can be as small as one LED or it may contain a cluster of LEDs that act as a unit.
A pixel, pel, dots, or picture element is a physical point in a raster image or the smallest visual element in a LED display device; in other words, its the smallest controllable element of a picture represented on the screen. LCD pixels are manufactured in a two-dimensional grid and are often represented using dots or squares.
Each pixel is a sample of an original image; more pixels typically provide more accurate representations of the original. The intensity of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black.
Pixel Pitch (sometimes called line pitch, dot pitch, stripe pitch, or phosphor pitch) is a specification for a computer display, computer printer, image scanner, and LED Signs that describes the distance between dots (sub-pixels) on a display screen.
Pixel pitch may be measured in linear units (smaller numbers meaning higher resolution), LED sign displays are measured in millimeters (mm).r
The matrix of a sign is the number of pixels vertically by the number of pixels horizontally. For example, if a sign has a matrix of 16×24, this means it has 16 pixels from top to bottom and 24 pixels from left to right. A larger matrix allows more text, images, and other graphic mediums to appear on the display at the same time.
The word candela means candle in Latin.
The candela is the SI base unit of luminous intensity; that is, luminous power per unit solid angle emitted by a point light source in a particular direction. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source’s spectrum, the contribution of each wavelength is weighted by the standard luminosity function (a model of the sensitivity of the human eye to different wavelengths). A common candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured.
NIT is a measurement of visible light intensity measured at the light source. Your computer screen probably has 200 to 300 NITs of visible brightness. With this many NITs it would be near impossible to read your monitor in the sunlight. That’s because your computer screen doesn’t have enough “visible light intensity”. Your LED Sign must have enough light intensity or it won’t be as visible in outdoor lighting conditions as your competitor’s.
5,000NIT minimum is the average for exterior LED displays.