either Wirja ta 'kiri ta' ġewwa mmexxija or outdoor waterproof full-color led display will generate heat in the process of operation, which will lead to the rise of the temperature of led display. ġeneralment, the indoor led display panel can naturally dissipate heat due to its low brightness, but the outdoor led advertising screen needs air conditioning or axial flow fan to dissipate heat due to its high brightness and high heat. because the led display is an electronic product, the rise of temperature will affect the light decay of the led display lamp beads, the working efficiency of driving ic, the service life of the led display, u l-bqija.
led display has great prospects for development because of its advantages of energy saving, protezzjoni ambjentali u ħajja twila. imma t-temperatura hija importanti ħafna għall-iskrin tal-wirja mmexxija. l-influwenza tat-temperatura fuq l-iskrin tal-wirja mmexxija hija relatata mal-ħajja u l-effiċjenza tad-dawl u l-kulur tal-iskrin tal-wirja mmexxija. għalhekk it-temperatura t-tajba hija importanti ħafna għall-iskrin tal-wirja mmexxija.
l-influwenza tat-temperatura fuq l-iskrin tal-wirja mmexxija għandha l-ħames punti li ġejjin:
1. Temperatura għolja se twassal għall-qerda sħiħa tal-iskrin tal-wirja mmexxija
(1) jekk it-temperatura tax-xogħol tal-wirja mmexxija taqbeż it-temperatura li ġġorr iċ-ċippa, l-effiċjenza luminuża tal-wirja mmexxija se tonqos malajr, li tirriżulta fi tħassir u ħsara ovvja tad-dawl.
(2) Wirjiet aktar immexxija huma inkapsulati b'reżina epossidika trasparenti. jekk it-temperatura tal-ġonta taqbeż it-temperatura tal-fażi solida ta 'transizzjoni (ġeneralment 125 ċ), il-materjal ta 'inkapsulament jinbidel għal forma tal-gomma u l-koeffiċjent ta' espansjoni termali se jiżdied sew, li jwassal għaċ-ċirkwit miftuħ u falliment tal-wirja mmexxija.
2. temperatura dejjem tiżdied se tqassar il-ħajja tal-wirja mmexxija
il-ħajja tal-wiri mmexxija hija riflessa fit-tħassir ħafif tagħha, jiġifieri, il-luminożità tonqos u tbaxxi fuq perjodu twil ta 'żmien sakemm tispiċċa fl-aħħar. ġeneralment, il-ħajja tal-wiri led huwa definit bħala l-ħin meta l-fluss luminuż jonqos b ' 30.
ġeneralment, there are several reasons for the light fading of led display.
(1) the defects in the materials of led display chips will multiply and multiply rapidly at high temperatures until they invade the luminous region and form a large number of non-radiative composite centers, which seriously reduces the luminous efficiency of led display. barra minn hekk, at high temperature, micro-defects in materials and fast-spreading impurities from interfaces and panels will also introduce into the luminous region, forming a large number of deep levels, which will also accelerate the optical decay of led display devices.
(2) transparent epoxy resin will denaturate and yellowing at high temperature, which will affect its light transmission performance. the higher the working temperature, the faster the process will go. this is another main reason for the light decay of led display screen.
(3) the optical decay of phosphors is also a major factor affecting the optical decay of led displays, because the attenuation of phosphors at high temperature is very serious.
għalhekk, high temperature is the main cause of led display light degradation and shorten the life of led display.
different brands of led display screen have different light fading. ġeneralment, the manufacturers of led display screen will give a standard light fading curve. the led display screen luminous flux attenuation caused by high temperature is irrecoverable. there is no irrecoverable luminous flux before the led display screen, which is called the “initial luminous flux” of the led display screen.
3. increasing temperature will reduce the luminous efficiency of led display
the reasons why temperature affects the light efficiency of led display include the following aspects:
(1) with the increase of temperature, the concentration of electrons and holes increases, the bandgap width decreases, and the electron mobility decreases.
(2) as the temperature rises, the radiation recombination probability of electrons and holes in the potential well decreases, resulting in non-radiation recombination (heat generation), which reduces the internal quantum efficiency of the led display screen.
(3) the blue light peak of the chip shifts to the long wave direction as the temperature rises, which makes the emission wavelength of the chip mismatch with the excitation wavelength of the phosphor, and also reduces the extraction efficiency of the external light of the white led display.
(4) as the temperature rises, the quantum efficiency of phosphor decreases, the light output decreases, and the external light extraction efficiency of led displays decreases.
(5) the properties of silica gel are greatly affected by ambient temperature. with the increase of temperature, the thermal stress inside the silica gel increases, which leads to the decrease of the refractive index of the silica gel, thus affecting the light efficiency of the led display screen.
