What is the effect of LED display under high temperature working condition?

Nowadays, the application of LED display is more and more extensive. In order to maximize the efficiency of display screens, application companies should have basic knowledge of LED display maintenance. Whether it is an indoor LED display or an outdoor LED display, the LED display will generate heat, which will cause the temperature of the LED display to rise.

But what effect does the LED display have under high temperature working conditions, do you know? Let's analyze it below. Usually, indoor LEDs have low brightness and generate less heat from the display screen, which can dissipate heat naturally; but outdoor LEDs have high brightness and display screens generate a lot of heat, which needs to be dissipated by air conditioners or axial fans. The LED display is an electronic product, and the temperature rise will affect the light attenuation of the LED display lamp beads and affect the working efficiency and service life of the driver IC.

LED display open circuit and failure If the working temperature of the LED display exceeds the load temperature of the chip, it will cause the LED to rapidly reduce the luminous efficiency of the display, produce obvious light decay, and cause damage; if the junction temperature of the LED exceeds the solid-state transition temperature (usually 125°C), the packaging material will become rubbery, and the coefficient of thermal expansion will rise sharply, causing the LED display and display screen to fail. Excessive temperature will affect the light decay of the LED screen of the display. The life of the LED display is manifested as its light decay, that is, as time goes by, the brightness becomes lower and lower until it is completely extinguished. Usually, the time when the luminous flux of an LED display is attenuated by 30 is defined as its lifespan.

High temperature is the main source of LED display light attenuation caused by high temperature and shortened LED display life. The light attenuation of LED displays is different, usually different LED display manufacturers will provide a set of standard light attenuation curves. As the temperature increases, the luminous efficiency of the LED will decrease. As the temperature increases, the concentration of electrons and holes will increase, the band gap will decrease, and the electron mobility will decrease; as the temperature increases, electrons and holes in potential traps will increase. The radiative recombination probability of the chip is reduced, resulting in non-radiative recombination (heat generation), thereby reducing the internal quantum efficiency of the LED display; as the temperature increases, the blue light peak of the chip shifts to the long-wave direction, causing the emission wavelength of the chip to be different from that of the phosphor The mismatch of the stimulating wavelength will also lead to the reduction of the external light extraction efficiency of the white light LED; the quantum efficiency of the phosphor decreases with the increase of the temperature, the light output rate decreases, the external light extraction efficiency of the LED display decreases, and the performance of the silica gel is affected by the ambient temperature. larger.

As the temperature rises, the thermal stress inside the silica gel increases, resulting in a decrease in the refractive index of the silica gel, which affects the light efficiency of the LED display.