LED lamp beads is a large number of manufacturers to survive the chips, LED lamp beads market mixed, product quality is uneven.
LED lamp beads is as the most important part of LED display,
when is the most important part of the LED lamp beads of good or bad, directly affect the quality of LED display.
LED display perspective depends on the angle of the LED lamp beads. At present, the LED display screen mostly selects the horizontal angle of view 100°, the vertical angle of view 50° ellipse led, the indoor led display screen chooses the horizontal vertical all is 170° SMD LED. The display on the expressway because of its particularity general selection of the round led of 30° angle is enough. The screens on some tall buildings require a higher vertical view. The angle of view and brightness are contradictory, the big angle of view will reduce brightness inevitably.The choice of perspective needs to be decided according to the specific use.
Led brightness is an important determinant of the brightness of the led display screen. The higher the brightness of the LED, the greater the use of current, to save power, to keep the LED stability benefits. LED has a different angle value, in the chip brightness has been determined, the smaller the angle, the brighter the LED, but the smaller the view of the display.
A balance point should be found in brightness, angle and price for display screen with different distance and different distance.
3. Failure efficiency
Due to the LED display by tens of thousands or even hundreds of thousands of groups of red, green, blue Three kinds of led composed of pixel points, any color led failure will affect the overall visual effect of the display.
In general, according to industry experience, the LED screen began to assemble to the aging 72-hour before the failure rate should not be higher than three out of 10,000 (refers to the LED lamp beads itself caused by the failure).
4. Antistatic ability
LED is a semiconductor device, sensitive to electrostatic, very easy to lead to electrostatic failure, so anti-static ability on the life of the display is critical.
In general, the LED body electrostatic mode test failure voltage should not be less than 2000V.
LED theory life of 100,000 hours, far more than LED display other parts of the working life, so long as the LED device quality assurance, work current appropriate, PCB cooling design reasonable, display production process rigorous, LED devices will be the display machine is one of the most durable parts. LED devices can determine the quality of LED display. China is the LED components of the production of large countries, but also led display system to do the gathering.
LED display of High-tech requirements is the future development trend, high-quality LED display requirements, not only on the LED display manufacturer's direction, but also implicated in LED display screen manufacturers
6, attenuation characteristics
LED display screen for a long time will appear brightness and display color inconsistencies, mainly because of the brightness of LED devices caused by attenuation. LED brightness attenuation will cause the screen brightness of the whole screen. Red, green, blue led brightness attenuation amplitude inconsistency will cause the color of the LED display screen inconsistent, is what we often say the display of the phenomenon of flowers. High-quality LED devices can well control the brightness attenuation amplitude. 1000 hours at ambient temperature light 20mA standard, red attenuation should be less than 2%, blue, green attenuation should be less than 10%, so blue, green led in the screen design as far as possible not to use 20mA current, preferably only 70% to 80% rated current.
Attenuation characteristics, in addition to the red, green, blue led itself, the use of current, PCB board heat dissipation design, display the use of ambient temperature and so on attenuation caused by the impact.
The size of the LED device affects the pixel distance of the LED display, i.e. the resolution. 5mm elliptical lamp beads is mainly used for above outdoor display P16
, 3mm lamp beads is mainly used for P12.5, P12, P10 outdoor display
, 2020 SMD LED is mainly used in P2, P3 and other indoor led display.
Under the premise of constant point spacing, led device size increases, can increase the display area, reduce the sense of particles, but because the area of black area decreases, will reduce the contrast; conversely, led size reduced, decreased the display area, the particle feeling increased, the black area area increases, increased the contrast.
LED display is made up of countless red, green, blue led pixel, each color led brightness, wavelength consistency determines the entire display brightness uniformity, white balance consistency, chroma consistency. In general, the display manufacturers require device suppliers to provide 5nm wavelength range and 1:1.3 brightness range of LEDs, these indicators can be achieved by the device supplier through the color separation machine grading.
Voltage consistency is generally not required. Red, green, blue three color LED angle consistency will seriously affect the consistency of the white balance of different angles, directly affect the display video color fidelity. To achieve the red, green, blue led in different angles of the brightness change matching consistency, the need in the packaging lens design, the original material selection of strict scientific design, depending on the technical level of packaging suppliers. Normal direction white balance again good display, if the LED angle consistency is not good, the whole screen different angles of the white balance effect will be bad. LED lamp beads angle consistency characteristics can be measured by the LED angle tester, for medium and high-end display is particularly important.