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LED lamps effect on LED display screen

Tag: LEDs, indoor/outdoor LED signs, LED lamps, full color LED display effect

LEDs_for_outdoor_full_color_display_screen

 

LED lamps as the highest cost and largest amount component of LED display billboards, which playing a leading role in the quality of indoor or outdoor LED signs. Here we are going to introduce you why LED lamp is the key component of LED display and how to identify the advantages and disadvantages of LED lamps?

 
Following are 3 reasons that LED light is the most important component of full color LED display screen?


Firstly, LEDs are the largest number of component used in LED full color screen, there might be hundreds or even thousands of LED lamps for one square meter.
Secondly, LEDs decided the subject of the whole screen optics display performance, which will directly impact on audience’s evaluation of the LED screen body.
Thirdly, LEDs take the largest proportion in the overall cost of the display, ranging from 30% to 70%.

 

How to identify quality of LED display lights?


1.Solder joint. Regular LED lamp manufacturers are using SMT processing, produced LED lights by solder paste and solder reflow process.


2.The quality of FPC. FPC has polygon copper and rolled copper. The foil of polygon copper is bulged, we could see it from solder pad to FPC connection.


3.Surface cleaning of LED lamps. If using SMT process for LED lights producing, the surface cleanliness will be very good and could not see any impurities and dirt


4.LED chips and production technique. It it hard to use your own eyes to see the differences must use aging equipment ans testing machine. If you compare a few LED lamps from different manufacturer and put them on the aging test machine for 24 hours or more. After that, you may test these different LED lights, the minimum brightness decay are the the best quality one. 

 

dip LEDs and smd LEDs

 

SMD LEDs and DIP LEDs


What is the effect of LED lamp on LED display billboards? 


1.Viewing angle
LED display monitor's viewing angle depends on the perspective of LED lights. At present most of the outdoor display using horizontal angle of 100° and the vertical angle of 50°DIP LEDs. Indoor display the select both horizontal and vertical viewing angles of 120° SMD LEDs.  The outdoor LED display on the highway because of its particularity it usually use 30° LED lamps. Some buildings required high for the vertical angle of LED advertising display. But large viewing angle will decrease the brightness, so the required angle will have to decide according to specific using. 


2.Brightness
LED brightness is an important deciding factor of LED display dimmer. The higher brightness is the larger the allowance for the use of current. LED has a different point values, in the case of chip brightness has been fixed, the smaller angle is , the LED will be more bright but the viewing angle of LED screen will smaller. In general, we should be selected to a 100-degree LED to ensure the display has enough perspective. According to the different display dot pitch and different sights, you should find a balance, brightness and angle, and price.


3.Failure Rate
LED display screen is consist of thousands even hundred thousands groups of green , blue, red LED pixels. Every color failure will have influence in the whole screen images. Generally, according to industry experience, at the beginning of LED screen assembly until it aging after 72 hours before shipping delivery, the failure rate should be no higher than 3‰.


4.ESD(electro-static discharge) Sensitivity
LED is a semiconductor device sensitive to static electricity. It is very easy to result in electro-static discharge. Therefore, anti-static capability is essential to the life of the display. Generally speaking, LED model of human body electrostatic voltage test failure should not be less than 2000V.


5.Lifespan
LED devices theoretical lifetime is 100,000 hours, which is much more longer than the other components. So as long as we assure the quality of LED devices, appropriate working current, reasonable PCB thermal design and strict production, LEDs will be one of the most durable components in the display. LED lights hold 70% cost of the overall screen, So the pros and cons of LED devices can determine the quality of LED display screen. China is the largest producer of LED lights and also a gathering place of producing LED Display System. High technology is a curtain trend of LED display screen in the future development. 


6.Decay Characteristic

LED display after long hours operating will appear the phenomenon of the decline in brightness and display different colors, which mainly because of LED device brightness attenuation. LED brightness decay will cause the display of the entire screen brightness decreases. Red, green and blue LED light inconsistencies can cause attenuation amplitude of the LED display color inconsistencies. High quality LED light devices are suitable for controlling the intensity attenuation range. According to 20mA standard at ordinary temperatures, red LED brightness decay should be less than 2%, blue and green LED attenuation should be less than 10%. Therefore, it is best to use 70% to 80% rated current for blue&green LED display design, try not to use the 20mA current.  The using current design, PCB board heat, display ambient temperature will also have some influence in LED screen board.


7.Size
LED size effects pixel distance of LED display screen, that is resolution. 5mm oval lamp is mainly used for P16 outdoor displays,3mm oval lamp is mainly used for P12.5, P12, P10 outdoor displays. 3528 SMD LED indoor display mainly used for P6, P8 and 2020 type SMD LED for P2, P3 and other indoor display.On the premise of constant pixel spacing, LED lamp size increases, can increase the display area and reduce the grainy. However, with the black area is reduced, it will reduce the contrast. By contrast, when LED the size decreases, the display area will be reduced and the black area will increase,which also increase the contrast.


8.Uniformity
Full color LED screen display is consist of thousands of red, green and blue LED lamps. The LED brightness uniformity and wavelength consistency of each color  determined the overall screen’s consistency of brightness, white balance and color. In general, the manufacturer requires the LEDs vendor provides 5nm wavelength range 1:1.3 brightness ranges.These indicators can be used by the device vendor achieved by Spectrophotometric color grading machine.


Since the LED has different angle, so the perspective of full color LED display screen has the same direction. When watch the screen at different angles, the brightness will be different. Thus, the angle of there color LED lights will seriously affect the consistency of the different white balance, which will also directly affect the LED video display’s color fidelity. Suppliers packaging technology determine the brightness uniformity of these 3 color LEDs. If the LED angle consistency is bad, the entire screen white balance effect will be worse too. LED angle Tester can test the angle consistency of LED lights, this value is essential for high-end LED screen displays. 

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