How to control and improve the quality of LED full color display? What are the important indicators that reflect the quality of LEDs for full-color LED displays ? First of all, LED devices are the most critical components of full-color LED displays for three reasons:
First of all, LED is the most used key component in the full-color screen, using thousands to tens of thousands of LEDs 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;
Again, LEDs account for the largest share of the overall cost of the display, ranging from 30% to 70%. The choice of LED determines the quality of the entire display by more than 50%. If the LED is not selected, the other parts of the display will not be able to compensate for the defect in the quality of the display.
The main indicators reflecting the quality of LEDs for full-color LED displays are:
First, the failure rate
Since the full-color display is composed of tens of thousands or even hundreds of thousands of red, green and blue LED elements, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to industry experience, the failure rate before the LED display starts to assemble to the aging 72 hours before shipment should be no more than three ten thousandth (refer to the failure caused by the LED device itself).
Second, antistatic ability
LEDs are semiconductor devices that are sensitive to static electricity and are highly susceptible to electrostatic failure. Therefore, antistatic capability is critical to the life of the display. In general, the human body electrostatic mode test failure voltage of LED should not be lower than 2000V.
Third, the attenuation characteristics
The red, green, and blue LEDs all have the characteristic of attenuating the brightness as the working time increases. The advantages and disadvantages of the LED chip , the quality of the auxiliary materials and the level of the packaging process determine the attenuation speed of the LED. Generally speaking, after 1000 hours and 20 milliamperes of 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 displayed for full color LED. The white balance after the screen is greatly affected, which in turn affects the display fidelity of the display.
Fourth, brightness
LED brightness is an important determinant of display brightness. The higher the brightness of the LED, the larger the margin of current used, which is beneficial for saving power and keeping the LED stable. LEDs have different angle values. In the case where 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 a sufficient viewing angle of the display. For displays with different dot pitches and different line of sight, a balance should be found in brightness, angle and price.
V. Consistency
The full-color display is composed of countless red, green and blue LEDs. The brightness and wavelength consistency of each color LED determine the brightness consistency, white balance consistency and chroma of the entire display. consistency. In general, display manufacturers require device vendors to provide LEDs with a wavelength range of 5 nm and a brightness range of 1:1.3. These specifications can be achieved by device suppliers through a spectral color separation machine. The consistency of the voltage is generally not required.
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