LED devices as the most critical components of full-color LED display for three reasons:
First of all, LED is the largest number of key devices in the use of full-color screen it will use thousands, even tens of thousands of LED per square meter;
Second, LED is the main part to determine the performance of entire screen, a direct impact on the audience's evaluation of the display.
Third, LED takes the largest proportion of the LED display overall cost, ranging from 30% to 70%. The choice of LED determines the quality of the entire display more than 50%. If you can not choose a good LED, no matter how good the other parts cannot make up for the defects of the display quality.
These important indicators reflect the LED quality of full-color LED display are:
I. The failure rate
As the full-color display is composed of the tens of thousands or even hundreds of thousands of red, green and blue elements of the LED, the failure of any color LED will affect the overall visual display. In general, according to industry experience, in the LED display assembly to the aging 72 hours before shipment failure rate should not be higher than three ten thousandths (refers to LED itself causes the failure)
II. Anti-static capacity
LED is a semiconductor, sensitive to static electricity, can easily lead to static failure, so the ability of anti-static display life is essential. In general, LED human body static mode test failure voltage should not be less than 2000V.
III. The attenuation characteristics
Red, green and blue LED have the characteristics that with the increase of working hours, brightness attenuation. LED chips, the quality of auxiliary materials and packaging technology level determine the decay rate of LED. In general, 1000 hours, lighting test at room temperature, the red LED attenuation should be less than 10%, blue and green LED attenuation should be less than 15%. The unity of Red, green, blue attenuation has a great impact on the white balance of full-color LED display Screen, thereby affecting the display fidelity.
LED brightness is an important determinant of display brightness. The higher the LED brightness, the greater the use of current margin, It is good to save power, maintain LED stability. LED has different angle values, in the case of the brightness of the chip is fixed, the smaller the angle, the brighter the LED, but the smaller the viewing angle of the display. General should choose 100 degrees LED to ensure that the display has enough perspective. For different point spacing and different sight distance of the display, should find a balance between brightness, angle and price.
Full-color display is composed of numerous image elements composed of red, green, blue LED. The consistency of each color LED's brightness, wavelength determines the consistency of the entire display brightness, white balance consistency, color consistency. In general, display manufacturers require device vendors to provide LED of 5nm wavelength range and 1: 1.3 brightness range, these indicators can be achieved by the device supplier through the spectral separation machine. Voltage consistency is generally not required.