1. LEDs are the main component determining the optical display performance of the entire screen, directly affecting viewers' perception of the display.
2. LEDs are the most numerous critical components used in a full-color screen, with thousands to tens of thousands of LEDs used per square meter.
3. LEDs account for the largest proportion of the overall cost of the display screen, ranging from 30% to 70%.
LEDs are the most critical component among all the accessories of a full-color LED display. The quality of the LEDs determines more than 50% of the overall quality of the display screen. The quality and parameters of LEDs specifically designed for full-color LED displays can be summarized into the following five key elements:
First, Brightness
LED brightness is a crucial factor determining the brightness of the display screen. The higher the LED brightness, the greater the current margin, which is beneficial for saving power and maintaining LED stability. LEDs have different viewing angles; given a fixed chip brightness, a smaller angle results in a brighter LED, but a smaller viewing angle for the display screen. Generally, 100-degree LEDs should be selected to ensure a sufficient viewing angle for the display screen. For display screens with different pixel pitches and viewing distances, a balance should be found between brightness, angle, and price.
Second, Failure Rate
Since a full-color display screen is composed of tens of thousands or even hundreds of thousands of pixels consisting of red, green, and blue LEDs, the failure of any color LED will affect the overall visual effect of the display screen. Generally, according to industry experience, the failure rate from the start of LED display assembly to 72 hours of aging before shipment should not exceed 0.03% (referring to failures caused by the LED device itself).
Third, Attenuation Characteristics
Red, green, and blue LEDs all exhibit a characteristic of brightness attenuation with increasing operating time. The quality of the LED chip, the quality of auxiliary materials, and the level of packaging technology determine the attenuation rate of the LEDs. Generally, after 1000 hours of continuous illumination at 20 mA at room temperature, the attenuation of red LEDs should be less than 10%, and the attenuation of blue and green LEDs should be less than 15%. The consistency of red, green, and blue attenuation greatly affects the white balance of the full-color LED display in the future, and thus affects the display fidelity of the screen. Fourth, Anti-static Capability
LEDs are semiconductor devices and are sensitive to static electricity, which can easily lead to electrostatic discharge failure. Therefore, anti-static capability is crucial for the lifespan of the display screen. Generally, the human body model electrostatic discharge failure voltage of LEDs should not be lower than 2000V.
Fifth, Consistency
A full-color LED display screen is composed of countless pixels made up of red, green, and blue LEDs. The consistency of the brightness and wavelength of each color LED determines the brightness consistency, white balance consistency, and chromaticity consistency of the entire display screen. Generally, display screen manufacturers require component suppliers to provide LEDs with a wavelength range of 5nm and a brightness range of 1:1.3. These specifications can be achieved by the component suppliers through sorting using a spectroradiometer. Voltage consistency is generally not required.
