It is a semiconductor Light Emitting Device. There are two types:
Through hole: the led is mounted through the printed circuit board.
SMD: the led is mounted on the surface of the printed circuit board (Surface Mounted Device)
El led SMD is smaller than led in-through hole.
A pixel based on led-through hole is usually composed of 3 leds (1 red, 1 green and 1 blue), but it occasionally uses other layouts, such as 2 red, 1 green and 1 blue (4 leds).
A pixel based on SMD leds typically uses the 3 in 1 SMD,which integrates the three leds in one package. Thanks to the smaller physical size and the ability to integrate multiple diodes in a single encapsulated, SMD technology allows the manufacture of a smaller pitch video screen compared to the hole-through technology.
The 3 in 1 SMD technology enables the manufacture of screens with greater clarity, since the distance between pixels is almost constant, regardless of the colour shown.
Due to this circumstance the maximum distance of a screen display using SMD led technology is increased by 25% compared to the traditional through hole encapsulated, even if using the same resolution.
Considering all these differences, led SMD technology is the most suitable for indoor purposes and led through hall is usually used for outdoor purposes.
Pixel:
It is the minimum homogeneous colour unit in a digital image. In full colour video screens each pixel consists of at least 3 leds.
Resolution:
It is the video screen size expressed in pixels.
Pitch:
It is the separation between pixels, usually expressed in millimetres.
Graphic surface:
It is the surface displaying the images and contents. It has no structural elements such as frames or rims.It is usually expressed in squares meters.
Control system:
Electronic devices used for the led video screen management
Minimum viewing distance:
It is the minimum distance from which the video screen images can be properly and clearly seen. As a general rule is equal to the pitch, but expressed in meters: the minimum viewing distance in a 10mm pitch video screen is 10m.
Maximum viewing distance:
It is the maximum distance from which the video screen images can be properly and clearly seen. It depends on the size of the screen graphical surface.
Vision angle:
The maximum angle from which a viewer can view the contents corrected emitted by the screen. Angles should be considered in the vertical and the horizontal point of view.
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