Heat, cool, what are the benefits of LED display? - - - - - - LED display - knowledge

by:Xinyao LCD     2020-07-06
Whether indoor full color LED display or outdoor LED, in the process of operation will generate heat, heat would result in higher temperature of LED display. Typically, indoor LED display because of low heat, less brightness can be natural cooling; But outdoor LED advertising screen due to their high brightness, the heat generated by the big, need to heat by way of air conditioning or axial flow fan, etc. Due to the LED display belongs to the electronic products, the rise of temperature will affect the LED display lights, light failure, influence the working efficiency of the driver IC, the service life of the LED display, etc. Led display because of its advantages of energy saving, environmental protection, long life provide development prospect extremely. But the temperature on the led display is very important, the influence of temperature on the led display: involves the led display and service life, light, color, etc. So the right temperature is vital for led display. The influence of temperature on the led display has the following five: one, the temperature is too high will be led to the destruction of the led display thoroughness, 1) Led display working temperature than the chip bearing temperature will reduce the luminous efficiency quickly led display, produces obvious droop, and cause damage; ( 2) Led display in a transparent epoxy resin encapsulation, more if the junction temperature more than solid phase transition temperature ( Usually for 125 ℃) , encapsulation materials will surge to rubber shape and thermal expansion coefficient, resulting in led display open and failure. Second, the temperature will shorten the life of the led display led display life characterized by its light failure, which is longer, the brightness is less and less, until finally go out. Usually define led display light flux attenuation of 30 time for its life. Usually the cause of led display light failure has the following several aspects: ( 1) Led display chip material defects in high temperature rapid proliferation, reproduction, and invasion light-emitting area, forming a lot of the radiative recombination centers, severely reduce the luminous efficiency of led display. In addition, under the condition of high temperature, micro defects within the material and the fast expansion of impurity from the interface and panels will also introduce the light emitting area, to form the deep level, will also accelerate the droop of led display device. ( 2) Transparent epoxy resin is modified, when high temperature yellow, affect the pervious to light performance, working temperature, the higher the faster the process will be carried out, this is the led display is a major cause of droop. ( 3) Droop of phosphor is also a major factor affecting the led display light failure, because of phosphor at high temperature attenuation is very severe. So, the high temperature is led display light failure, shorten the service life of led display primary sources. Different brands of led display light failure is different, usually led display manufacturer will give you a set of standard droop curve. High temperature caused by the led display light flux attenuation is unrecoverable, led display not happened before the unrecoverable light attenuation of luminous flux, referred to as the 'initial luminous flux of led display. Three, temperature can reduce temperature affect the led luminous efficiency of led display screen photosynthetic efficiency reasons include the following aspects: ( 1) Temperature, the concentration of electrons and holes will increase, the forbidden band width will decrease, electron mobility will decrease. ( 2) Temperature increases, the potential well of radiative recombination of electrons and holes, less likely to cause the radiative recombination ( Produce heat) To reduce the internal quantum efficiency of led display. ( 3) Temperature lead to blue chip peaks shift towards long wave, make the emission wavelength of chips and excitation wavelength of phosphor do not match, can cause the white light led display external light extraction efficiency lower. ( 4) As temperatures rise, phosphor quantum efficiency is reduced, the light, led display external light extraction efficiency. ( 5) Silica gel performance are greatly influenced by environmental temperature. As the temperature increases, the silicone internal thermal stress increase, results in the decrease of the refractive index of a silica gel, which affects led display lights. Four, temperature on the led display light wavelength ( Light color) The influence of the wavelength of light emitting peak wavelength can generally be divided into led display and the main wavelength. Peak wavelength of the light intensity of the largest wavelength and the dominant wavelength can be determined by the X, Y chromaticity coordinates, reflects the perception by the human eye color. Obviously, the junction temperature caused by the led display light wavelength change will directly cause the human to led display light color different feelings. For a led display device, light emitting area materials forbidden band width values directly determines the wavelength of light emitting device or color. Temperature of the forbidden band width of materials will decrease, lead to light wavelengths longer, the color red shift. Five, the temperature too high can limit the maximum current injection of led display above is the introduction of the influence of temperature on the led display screen, through the introduction of the above that the influence of temperature on the led display is very large. So the suitable, appropriate temperature is very important for led display. LED display when the choose and buy, should pay attention to choose LED display chip brands, packaging manufacturers, drive IC, switching power supply brand, brand is good or bad will affect the LED display itself product quality, and high degree of brand products, its itself produces less heat, also can better control the temperature of the LED display, so as to prolong the service life of the LED display. To create each exciting scene!
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