The Influence Of LED Bead On LED Screen
Aug 16, 2021
1.the Angle of view
The perspective of LED display is determined by the perspective of LED beads. At present, most LED displays choose elliptical LED with horizontal viewing Angle of 100° and vertical viewing Angle of 50°, while indoor displays choose patch LED with both horizontal and vertical viewing Angle of 170°. Due to its particularity, the display screen on the expressway generally selects the circular LED of 30° Angle of view. Some high-rise displays require more vertical viewing. The Angle of view and the brightness are mutually contradictory, the large Angle of view will inevitably reduce the brightness. The choice of perspective needs to be based on the specific use.
2.brightness
LED brightness is an important determinant of display brightness. The higher the LED brightness, the greater the use of current allowance, to save power consumption, to keep the LED stable. Leds have different Angle values, in the case of the chip brightness has been fixed, the smaller the Angle, the LED is brighter, but the display Angle is smaller. A balance point should be found in brightness, Angle and price for the display with different pitch and different line-of-sight.
3. Failure rate
Because the full-color display is composed of tens of thousands or even hundreds of thousands of groups of red, green and blue LED pixels, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to the industry experience, the failure rate of LED display from the beginning of the assembly to the aging 72 hours before shipment should not be higher than 3/10000 (refers to the failure caused by the LED bead itself).
4, antistatic ability
LED is a semiconductor device, sensitive to static electricity, easy to cause electrostatic failure, so the anti-static ability is critical to the life of the display. In general, the human static mode test failure voltage of LED should not be less than 2000V.
5.life
The theoretical life of LED devices is 100,000 hours, much longer than the working life of other LED display components, so as long as the quality of LED devices is guaranteed, the working current is appropriate, the DESIGN of PCB heat dissipation is reasonable, and the production process of the display is rigorous, THE LED device will be one of the most durable parts of the display machine.
LED devices can determine the quality of LED display. China is not only a major producer of LED devices, but also a gathering place of LED display manufacturing. The high technology requirement of LED display is the development trend of the future. The high quality requirement of LED display is not only about the trend of LED display manufacturers, but also the development of LED display device manufacturers.
6. Attenuation characteristics
LED display after working for a long time will appear brightness drop and display color inconsistent phenomenon, mainly due to the LED device brightness attenuation. The attenuation of LED brightness will cause the brightness of the whole screen to decrease. Red, green, blue LED brightness attenuation range is inconsistent will cause LED display color is inconsistent, is we often say the display spent phenomenon. High quality LED devices can well control the brightness attenuation. According to the standard of 1000 hours room temperature lit 20mA, red attenuation should be less than 2%, blue and green attenuation should be less than 10%, so blue and green LED in the display design as far as possible do not use 20mA current, it is best to use only 70% to 80% of the rated current.
In addition to the characteristics of red, green and blue LEDS, the attenuation characteristics are affected by the current used, the heat dissipation design of PCB board and the ambient temperature of the display screen.
7. size
The size of THE LED device affects the pixel distance of the LED display, that is, the resolution.
5mm oval light is mainly used for P16 above outdoor display, 3mm oval light is mainly used for P12.5, P12, P10 outdoor display, 2020 patch LED is mainly used for P2, P3 and other indoor display. Under the premise of constant point spacing, the size of LED device increases, which can increase the display area and reduce the particle sense, but due to the reduction of black area area, will reduce the contrast; On the contrary, the LED size is reduced, which reduces the display area, increases the particle sense, and increases the black area area, which increases the contrast.
8. Consistency
LED display is made up of countless red, green and blue LED pixels. The brightness and wavelength consistency of each color LED determines the brightness consistency, white balance consistency and chromatism consistency of the whole display. Generally speaking, display manufacturers require device suppliers to provide LED with a wavelength range of 5nm and a brightness range of 1.1.3. These indicators can be achieved by device suppliers through the classification of color splitter.
Voltage consistency is generally not required.
The consistency of the red, green and blue LED angles will seriously affect the consistency of the white balance of different angles, and directly affect the fidelity of the video color of the display. In order to achieve the matching consistency of the brightness changes of red, green and blue LEDS at different angles, it is necessary to carry out strict scientific design in the design of packaging lens and the selection of raw materials, which depends on the technical level of packaging suppliers. No matter how good the normal white balance is, if the LED Angle consistency is not good, the white balance effect of different angles of the whole screen will be bad. LED bead Angle consistency characteristics can be measured by LED Angle comprehensive tester, especially for high-grade display.
