Inventory of factors affecting the service life of LED display

September 09, 2020

The LED display is composed of a row of light-emitting diodes, so the quality of the LED directly affects the overall quality of the display. There are five indicators that determine the quality of LEDs: brightness and viewing angle, uniformity and clarity, pixel runaway rate, life, energy consumption and energy efficiency. The factors that affect the life of LED display screen are internal and external factors. The internal factors include the performance of peripheral components, the performance of LED light-emitting devices, and the product's anti-fatigue performance; the internal factors include the working environment of the LED display screen, and so on. Heat dissipation is a key factor that affects the quality and service life of LED displays.

LED (Light Emitting Diode) is as important to the display screen as the engine of the car and the compressor of the air conditioner. Selecting an LED with excellent performance is the basic condition for completing a high-performance LED display. However, even with the same side dishes, the same seasonings, and the same stove, chefs of different levels may cook different dishes. Therefore, whether LEDs can be used well is the touchstone for testing display manufacturers. It is generally believed that the following five key performance indicators of the display are closely related to the LED quality parameters: brightness and viewing angle, uniformity and clarity, pixel runaway rate, life, energy consumption and energy efficiency.

1. Brightness and viewing angle

The brightness of the display mainly depends on the luminous intensity and LED density of the LED. In recent years, LEDs have emerged with new technologies in substrates, epitaxy, chips, and packaging. In particular, the stability and maturity of indium tin oxide (ITO) current spreading layer technology and technology have greatly improved the luminous intensity of LEDs. At present, when the horizontal viewing angle is 110 degrees and the vertical viewing angle is 50 degrees, the luminous intensity of the green tube has reached 4000mcd, the red tube is 1500mcd, and the blue tube is 1000mcd. When the pixel pitch is 20mm, The brightness of the display can reach more than 10000nit. The display can work around the clock in any environment.

When it comes to the viewing angle of the display screen, there is a phenomenon worthy of our consideration: LED display screens, especially outdoor display screens, people's viewing angles are basically from the bottom up, and from the existing LED display product form, there are Half of the luminous flux disappears into the vast sky. In today's energy shortage, do we have a more reasonable solution? Worth pondering.

2. Uniformity and clarity

With the development of LED display technology to this day, uniformity has become the most important indicator for measuring the quality of display screens. It is often said that the LED display is brilliant and brilliant, which is a metaphor for the serious unevenness between pixels and modules. A professional statement is the dust effect and mosaic phenomenon.

The main causes of unevenness are: the inconsistency of LED performance parameters; the lack of assembly accuracy of the display during production and installation; the consistency of the electrical parameters of other electronic components; the irregular design of modules and PCBs.

The inconsistency of LED performance parameters is the main reason. The inconsistency of these performance parameters mainly includes: inconsistency of light intensity, inconsistency of optical axis, inconsistency of color coordinates, inconsistency of distribution curve of light intensity of each primary color, and inconsistency of attenuation characteristics. How to solve the inconsistency of LED performance parameters, there are currently two main technical approaches in the industry: one is to further subdivide the LED specification parameters to improve the consistency of LED performance; the second is to improve the display through subsequent correction Uniformity. Subsequent corrections have also evolved from early module corrections and module corrections to point-by-point corrections today. The correction technology is developed from simple light intensity correction to light color coordinate correction.

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