Selection and use of dedicated LEDs for full-color LED displays

How to choose led display and what to pay attention to?
First of all, LEDs are the most used key components in the full-color screen, and thousands to tens of thousands of LEDs are used per square meter;
Secondly, LED is the main body that determines the optical display performance of the whole screen, which directly affects the audience’s evaluation of the display screen;
Third, LEDs account for the largest proportion of the overall cost of the display, ranging from 30% to 70%. The choice of LED determines more than 50% of the quality of the entire display. If you fail to choose a good LED, no matter how good the other components of the display screen are, it cannot make up for the defects of the display screen quality.

The important indicators that reflect the quality of LEDs dedicated to full-color LED displays are:
1. Failure rate
Since the full-color display is composed of tens of thousands or even hundreds of thousands of pixel points composed of three types of red, green, and blue LEDs, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to industry experience, the failure rate from the start of assembly to aging 72 hours before shipment should not be higher than 3/10,000 (referring to the failure caused by the LED device itself).
2. Antistatic ability
LED is a semiconductor device, which is sensitive to static electricity and can easily lead to static electricity failure. Therefore, the anti-static ability is very important to the life of the display screen. Generally speaking, the human body electrostatic mode test failure voltage of LED should not be lower than .
3. Attenuation characteristics
Red, green, and blue LEDs all have the characteristic of brightness decay with the increase of operating time. The quality of LED chips, the quality of auxiliary materials and the level of packaging technology determine the decay speed of LEDs. Generally speaking, after 1 hour, 20 mA normal temperature lighting test, the attenuation of red LED should be less than 10%, and the attenuation of blue and green LED should be less than 15%. The consistency of red, green and blue attenuation is very important for full color LED display. The white balance in the future has a great impact, which in turn affects the display fidelity of the display.

4. Brightness
LED brightness is an important determinant of display brightness. The higher the brightness of the LED, the greater the margin of the current used, which is good for saving power consumption and keeping the LED stable. LEDs have different angle values. When the brightness of the chip is fixed, the smaller the angle, the brighter the LED, but the smaller the viewing angle of the display. Generally, LEDs of high degree should be selected to ensure sufficient viewing angle of the display screen. For displays with different dot pitches and different viewing distances, a balance point should be found in brightness, angle and price.
5. Consistency
The full-color display screen is composed of numerous picture elements composed 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 of the entire display screen. consistency. Generally speaking, display manufacturers require device suppliers to provide LEDs with a wavelength range of 5nm and a brightness range of 1:1.3. These indicators can be achieved by device suppliers through grading through a spectrophotometer. The consistency of voltage is generally not required.