1. Failure rate
Since a full-color LED display is composed of tens of thousands or even hundreds of thousands of pixels composed of three 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 of the full-color LED display from the start of assembly to 72 hours of aging before shipment should be no more than three ten thousandths (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 cause static failure. Therefore, the antistatic ability is very important to the life of the display screen. Generally speaking, the failure voltage of the human body electrostatic mode test of the LED should not be lower than 2000V.
3. Attenuation characteristics
The red, green, and blue LEDs all have the characteristics of brightness attenuation as the working time increases. The quality of LED chips, the quality of auxiliary materials and the level of packaging technology determine the attenuation speed of LEDs. Generally speaking, after 1000 hours, 20 mA normal temperature lighting test, the attenuation of the red LED should be less than 10%, and the attenuation of the blue and green LEDs should be less than 15%. The uniformity of red, green, and blue attenuation has a great impact on the white balance of the full-color LED display in the future, which in turn affects the display fidelity of the display.
LED brightness is an important determinant of display brightness. The higher the brightness of the LED, the greater the margin for the use of current, which is good for saving power 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, a 100-degree LED should be selected to ensure sufficient viewing angle of the display screen. For displays with different dot pitches and different viewing distances, a balance should be found in brightness, angle, and price.
The full-color LED display is composed of countless red, green and blue LEDs. The brightness and wavelength consistency of each color LED determines the brightness consistency, white balance consistency and chromaticity of the entire display. consistency. Generally speaking, full-color LED 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 the device supplier through a spectroscopy machine. The consistency of voltage is generally not required. Since the LED is angled, the full-color LED display also has angular directionality, that is, when viewed from different angles, its brightness will increase or decrease.
In this way, the angle consistency of the red, green, and blue LEDs will seriously affect the consistency of the white balance at different angles, and directly affect the fidelity of the video color of the display screen. To achieve the matching consistency of the brightness changes of the red, green, and blue LEDs at different angles, it is necessary to strictly carry out scientific design in the package lens design and raw material selection, which depends on the technical level of the package supplier. For a full-color LED display with the best directional white balance, if the LED angle consistency is not good, the white balance effect of the whole screen at different angles will be bad. The angle consistency characteristics of LED devices can be measured with an LED angle comprehensive tester, which is particularly important for medium and high-end displays.