For full color LED screens, SMD LED beads can be said the most important part. The quality of LED chips plays a key role in determining the quality of LED displays.
LED beads are the mostly used components in full color LED screens, there are probably thousands or even tens of thousands of SMD LED beads on every square meter of the lighting board used in LED displays. In addition, SMD LEDs also directly determine the performance, color saturation and sharpness of LED screens.
The main performance figure of SMD LED beads mainly determines:
1) The brightness of LED screens: the brighter the LED chips/the greater the margin of current, the better the quality of LED screens. This type of screens has higher reliability and can save more electricity. LED chips have different angles. With the same brightness, the narrow the angle, the brighter the LED beads, but the visual angle will become narrow all together. Normally, manufacturers choose LED beads with beam angle of 100 degrees to 110 degrees to meet the requirements of visual angle and brightness of LED screens.
2) The failure rate of LED full-color display: G24 LED display is composed by tens/hundreds of thousands of red/green/blue SMD LED beads. The failure rate of LED beads with good quality will be no more than the ten-thousandth after a 72-hour ageing test.
3) The attenuation characteristics of LED full-color display: definitely, the brightness of LED beads will reduce over time, which is also known as light attenuation. The speed of light attenuation is mainly determined by the quality of LED chips, assisted materials and packaging process. Normally, under 20mA driving current, at room temperature, after 1000-hour aging test, the light attenuation of red chips should be less than 7%, and the light attenuation of greed/blue chips should be less than 10%. The attenuation rate of red/green/blue chips has great influence on the white balance of full-color LED screens, and consequently their fidelity.
4) Anti-static ability of LED display: since SMD LED chips are semiconductor devices, they are very sensitive to static electricity, easily leading to static electricity failures. So the anti-static ability is critical to the life of LED displays. Generally speaking, the threshold voltage of body static mode tests of LED beads should not be less than 2000V.