LED Brightness: The brightness of a light-emitting diode (LED) is generally expressed in luminous intensity, measured in candela (cd). 1000 μCd (microcandela) = 1 mcd (millicandela), 1000 mcd = 1 cd. The luminous intensity of a single indoor LED is typically 500 μCd - 50 mcd, while the luminous intensity of a single outdoor LED is typically 100 mcd - 1000 mcd, or even above 1000 mcd.
LED Pixel Modules: LEDs are arranged in matrices or segments and prefabricated into standard-sized modules. Common indoor display modules include 8x8 pixel modules and 7-segment digital modules. Outdoor display pixel modules are available in 4x4, 8x8, and 8x16 pixel specifications. Because each pixel in an outdoor display consists of two or more LED bundles, they are also called bundled modules.
Pixels and Pixel Diameter: Each individually controllable LED light-emitting unit (dot) in an LED display is called a pixel (or pixel cell). Pixel diameter (∮) refers to the diameter of each pixel, measured in millimeters.
For indoor displays, a single LED is typically used, and it is circular in shape. Common pixel diameters for indoor displays include ∮3.0, ∮3.75, ∮5.0, and ∮8.0, with ∮3.75 and ∮5.0 being the most common.
In outdoor environments, to improve brightness and increase viewing distance, a pixel contains two or more clustered LEDs. Since clustered LEDs are generally not circular, the pixel diameter for outdoor displays is usually expressed as the average spacing between pairs of pixels: □10, □11.5, □16, □22, □25.
Dot pitch, pixel density, and information capacity: The center-to-center distance or dot pitch of two pixels on an LED display; the number of pixels per unit area is called pixel density; the amount of displayed content per unit area is called information capacity. These three terms essentially describe the same concept: pixel pitch reflects pixel density as the distance between any two pixels; pixel pitch and pixel density are physical properties of a display screen. Information capacity is the quantitative unit of information carrying capacity of pixel density.
The smaller the pixel pitch, the higher the pixel density, the greater the information capacity, and the closer the suitable viewing distance.
The larger the pixel pitch, the lower the pixel density, the less the information capacity, and the farther the suitable viewing distance.
Resolution: The number of rows and columns of pixels on an LED display screen is called the resolution. Resolution is the total number of pixels on the screen, which determines the information capacity of a display screen.
LED Display Screen Structure: An LED display screen is constructed by assembling LED pixel modules into a matrix according to actual needs, along with dedicated display driver circuits, DC regulated power supplies, software, frames, and external decorations.
Grayscale: Grayscale refers to the degree of brightness variation of a pixel. A primary color typically has 8 to 12 grayscale levels. For example, if each primary color has 256 gray levels, a dual-primary-color screen can display 256 × 256 = 64k colors, and is also called a 256-color display screen.
