In today's increasingly widespread use of LED display screens, in order to maximize the benefits of display screen use, application companies should have the basic common sense of LED display maintenance. Whether it is an indoor LED display or an outdoor LED display, heat will be generated during operation, and the generated heat will cause the temperature of the LED display to rise. But do you know what effect does the display have under high temperature working conditions? The following editor will analyze and analyze it with everyone.
Under normal circumstances, indoor LED displays produce less heat due to low brightness and can naturally dissipate heat; however, outdoor LED displays generate large amounts of heat due to high brightness and need to be dissipated by air conditioners or axial fans. Since the LED display is an electronic product, the increase in temperature will affect the light decay of the LED display lamp beads, affect the working efficiency of the driver IC, and the service life of the LED display.
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LED display open circuit and failure
The working temperature of the LED display exceeds the load temperature of the chip, which will cause the luminous efficiency of the LED display to decrease rapidly, cause obvious light decay, and cause damage; the LED display is mostly encapsulated with transparent epoxy resin, if the junction temperature exceeds the solid phase transition At temperature (usually 125°C), the packaging material will transform to a rubbery shape and the thermal expansion coefficient will rise sharply, which will cause the LED display to open and fail.
Excessive temperature will affect the light decay of the display LED screen
The life of the LED display is manifested 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 life of the LED display when the luminous flux decays by 30. High temperature is the main source of LED display light decay and shortening the life of the LED display. The light attenuation of different brands of LED displays is different, usually led display manufacturers will give a set of standard light attenuation curve. The attenuation of the luminous flux of the LED display caused by high temperature is unrecoverable, and the luminous flux before the unrecoverable light attenuation of the LED display does not occur, which is called the "initial luminous flux" of the LED display.
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Increase in temperature will reduce the luminous efficiency of the LED screen
As the temperature rises, the concentration of electrons and holes will increase, the band gap will decrease, and the electron mobility will decrease; as the temperature rises, the probability of radiation recombination of electrons and holes in the potential well decreases, resulting in non-radiative recombination. Heat), thereby reducing the internal quantum efficiency of the LED display; the increase in temperature causes the blue peak of the chip to shift to the long wave direction, which makes the emission wavelength of the chip and the excitation wavelength of the phosphor do not match, and it will also cause the external light of the white LED display. The extraction efficiency is reduced; 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 screen decreases; the performance of the silica gel is greatly affected by the ambient temperature. As the temperature increases, the thermal stress inside the silica gel increases, resulting in a decrease in the refractive index of the silica gel, thereby affecting the light efficiency of the LED display.
The influence of temperature on the luminous wavelength of LED screen
The luminous wavelength of the LED display screen can generally be divided into the peak wavelength and the 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, reflecting the color perceived by the human eye. Obviously, the change in the light-emitting wavelength of the LED display screen caused by the junction temperature will directly cause the human eyes to have different perceptions of the light-emitting color of the LED display screen. For an LED display device, the band gap value of the material in the light-emitting zone directly determines the wavelength or color of the device's light emission. As the temperature rises, the band gap of the material will decrease, which will cause the device to emit longer wavelengths and red shift the color.
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Excessive temperature will limit the maximum injection current of the LED screen
When purchasing an LED display, pay attention to choosing the LED display chip brand, packaging manufacturer, driver IC brand, and switching power supply brand. The quality of the brand will affect the quality of the LED display itself, and the brand is high. The product itself generates less heat and can better control the temperature of the LED display, thereby prolonging the service life of the LED display.
LED display has great development prospects due to its advantages of energy saving, environmental protection and long life. LED display is more sensitive to temperature: it will affect the life, light efficiency, color, etc. of the LED display. So the right temperature is very important for the LED display.
