Eight aspects of the impact of LED lamp beads on LED display screens

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Eight aspects of the impact of LED lamp beads on LED display screens [Copy link]

1. Viewing Angle

The viewing angle of LED display is determined by the viewing angle of LED lamp beads. At present, most outdoor display screens use elliptical LEDs with a horizontal viewing angle of 100° and a vertical viewing angle of 50°, while indoor display screens use SMD LEDs with a horizontal and vertical viewing angle of 120°. Due to its particularity, the display screens on highways generally use circular LEDs with a viewing angle of 30°. Some display screens on high-rise buildings have higher requirements for vertical viewing angles. Viewing angle and brightness are contradictory, and a large viewing angle will inevitably reduce brightness. The choice of viewing angle needs to be determined according to the specific purpose. 2. Brightness LED brightness is an important factor in determining the brightness of the display. The higher the LED brightness, the greater the margin of current used, which is beneficial for saving power and maintaining LED stability. LEDs have different angle values. When the chip brightness is fixed, the smaller the angle, the brighter the LED, but the viewing angle of the display is smaller. Generally, a 100-degree LED should be selected to ensure sufficient viewing angle of the display. For displays with different dot pitches and different viewing distances, a balance should be found between brightness, angle and price.

3. Failure rate

Since the full-color display is composed of tens of thousands or even hundreds of thousands of pixels composed of red, green and blue LEDs, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to industry experience, the failure rate of the LED display from the beginning of assembly to aging for 72 hours before shipment should not be higher than 0.03% (referring to the failure caused by the LED lamp beads themselves). 4. Antistatic ability LED is a semiconductor device, which is sensitive to static electricity and can easily cause static electricity failure. Therefore, antistatic ability is crucial to the life of the display. Generally speaking, the failure voltage of the human body static mode test of LED should not be less than 2000V.

5. Lifespan

The theoretical lifespan of LED devices is 100,000 hours, which is much longer than the working lifespan of other components of LED display screens. Therefore, as long as the quality of LED devices is guaranteed, the working current is appropriate, the PCB heat dissipation design is reasonable, and the display screen production process is rigorous, LED devices will be one of the most durable components in the entire display screen.

LED devices account for 70% of the price of LED display screens, so LED devices can determine the quality of LED display screens. my country is not only a major producer of LED devices, but also a gathering place for LED display screens. The high technical requirements of LED display screens are the future development trend. The high quality requirements of LED display screens are not only related to the direction of LED display screen manufacturers, but also involve the development of LED display screen device manufacturers. From the control of LED devices, China's transformation from a major LED display screen manufacturing country to a powerful LED display screen manufacturing country is promoted.

6. Attenuation characteristics

After working for a long time, the LED display screen will have a decrease in brightness and inconsistent display color, which is mainly caused by the brightness attenuation of LED devices. The attenuation of LED brightness will cause the brightness of the entire display screen to decrease. The inconsistency of the brightness attenuation of red, green and blue LEDs will cause the color of the LED display screen to be inconsistent, which is what we often call the phenomenon of the display screen being blurred. High-quality LED devices can well control the brightness attenuation amplitude. According to the 20mA standard of lighting at room temperature for 1000 hours, the red attenuation should be less than 2%, and the blue and green attenuation should be less than 10%. Therefore, when designing the display screen, try not to use 20mA current for blue and green LEDs. It is best to use only 70% to 80% of the rated current. In addition to the characteristics of the red, green and blue LEDs themselves, the attenuation characteristics are also affected by the current used, the heat dissipation design of the 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 screen, that is, the resolution. 5mm elliptical lamps are mainly used for outdoor displays above P16, 3mm elliptical lamps are mainly used for outdoor displays of P12.5, P12, and P10, 3528 SMD LEDs are mainly used for indoor displays of P6 and P8, and 2020 SMD LEDs are mainly used for indoor displays such as P2 and P3. Under the premise of unchanged dot pitch, the increase in the size of LED devices can increase the display area and reduce the sense of grain, but the contrast will be reduced due to the reduction in the black area; on the contrary, the reduction in LED size reduces the display area, the sense of grain increases, the black area increases, and the contrast is increased.

8. Consistency

The full-color display is composed of pixels composed of countless red, green and blue LEDs. The brightness and wavelength consistency of each color LED determine the brightness consistency, white balance consistency and color consistency of the entire display. Generally speaking, display manufacturers require device suppliers to provide LEDs with a wavelength range of 5nm and a brightness range of 1:1.3. These indicators can be achieved by device suppliers through grading by spectrophotometers. Voltage consistency is generally not required.

Since LEDs are angled, full-color LED displays also have angle directionality, that is, when viewed at different angles, their brightness will increase or decrease. In this way, the angle consistency of the red, green and blue color LEDs will seriously affect the consistency of white balance at different angles, and directly affect the fidelity of the video color of the display. To achieve the matching consistency of the brightness changes of the red, green and blue LEDs at different angles, strict scientific design is required in the packaging lens design and raw material selection, which depends on the technical level of the packaging supplier. No matter how good the white balance of the display screen in the normal direction is, if the angle consistency of the LED is not good, the white balance effect of the whole screen at different angles will be poor. The angle consistency characteristics of LED lamp beads can be measured by LED angle comprehensive tester, which is particularly important for mid- and high-end display screens.

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Thanks for sharing. Although I am not a professional, I would like to know more about it.