Today, as LED displays are increasingly used in applications, in order to maximize the benefits of display use, app stores should have basic knowledge about LED display maintenance. Whether it is an indoor LED display or an outdoor LED display, heat will be generated during operation, and the heat generated will cause the temperature of the LED display to increase. But do you know what impact the display will have under high-temperature working conditions? The editor will analyze it with everyone below.

Under normal circumstances, indoor LED displays generate less heat due to low brightness and can dissipate heat naturally; however, outdoor LED displays generate large amounts of heat due to high brightness and require heat dissipation through air conditioners or axial flow fans. Since LED displays are electronic products, the increase in temperature will affect the light attenuation of the LED display lamp beads, the working efficiency of the driver IC, and the service life of the LED display.

Effects of excessive temperature

01. Luminous efficiency decreases rapidly

The working temperature of the LED display exceeds the load-bearing temperature of the chip, which will rapidly reduce the luminous efficiency of the LED display, produce obvious light attenuation, and cause damage; LED displays are mostly encapsulated with transparent epoxy resin. If the junction temperature exceeds the solid phase transition temperature (usually 125°C), the packaging material will transform to rubbery and the thermal expansion coefficient will rise sharply, causing the LED display to open circuit and fail.

02. Excessive temperature will affect the light attenuation of the LED display.

The life of the LED display is reflected by its light decay, that is, as time goes by, the brightness becomes lower and lower until it finally goes out. It is usually defined as the time when the luminous flux of the LED display screen decays by 30% as its lifespan. High temperature is the main cause of light failure of LED displays and shortening the life of LED displays. The light attenuation of different brands of LED displays is different. Usually LED display manufacturers will provide a set of standard light attenuation curves. The luminous flux attenuation of the LED display screen caused by high temperature is irrecoverable. The luminous flux of the LED display screen before irrecoverable light attenuation occurs is called the "initial luminous flux" of the LED display screen.

03. Rising temperature will reduce the luminous efficiency of the LED display

As the temperature increases, the concentration of electrons and holes will increase, the bandgap width will decrease, and the electron mobility will decrease; as the temperature increases, the probability of radiative recombination of electrons and holes in the potential well decreases, resulting in non-radiative recombination (generating Heat), thereby reducing the internal quantum efficiency of the LED display; the temperature increase causes the blue light wave peak of the chip to shift to the long wavelength direction, causing the chip's emission wavelength to mismatch the excitation wavelength of the phosphor, which will also cause the external light of the white LED display to The extraction efficiency decreases; as the temperature rises, the quantum efficiency of the phosphor decreases, the light emission decreases, and the external light extraction efficiency of the LED display decreases; the performance of silica gel is greatly affected by the ambient temperature. As the temperature increases, the thermal stress inside the silica gel increases, causing the refractive index of the silica gel to decrease, thus affecting the light efficiency of the LED display.

04. The effect of temperature on the luminous wavelength (light color) of the LED display

The luminous wavelength of LED display screen can generally be divided into peak wavelength and dominant wavelength. The peak wavelength is the wavelength with the maximum light intensity, and the dominant wavelength can be determined by the X and Y chromaticity coordinates, which reflects the color perceived by the human eye. Obviously, the change in the luminous wavelength of the LED display caused by the junction temperature will directly cause the human eye to have different feelings about the luminous color of the LED display. For an LED display device, the bandgap value of the light-emitting area material directly determines the wavelength or color of the device's light emission. As the temperature increases, the material's bandgap width will decrease, causing the device's emission wavelength to become longer and the color to red shift.

05. Excessive temperature will limit the maximum injection current of the LED display.

When purchasing an LED display, you should pay attention to the LED display chip brand, packaging manufacturer, driver IC brand, and switching power supply brand. The quality of the brand will affect the product quality of the LED display itself, and those with high brand awareness The product itself generates less heat and can better control the temperature of the LED display, thus extending the service life of the LED display.

LED display screens have great development prospects because of their advantages such as energy saving, environmental protection, and long life. LED display screens are relatively sensitive to temperature: it will affect the life, light efficiency, color, etc. of the LED display screen. So the right temperature is crucial for LED displays.