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As the most expensive and most used component of LED display, LED lamp beads play a leading role in the quality of LED display. Today we will introduce to you why LED lamp beads are the most critical component of LED display screens, and how to distinguish the advantages and disadvantages of LED lamp beads?

The most critical component of a full-color LED display is LED lamp beads. There are three reasons:

1. LED is the most used key component in the full-color screen machine, and thousands to millions of LEDs will be used per square meter;

2. LED is the main body that determines the optical display performance of the entire screen, which directly affects the audience's evaluation of the display;

3. LED accounts for the largest proportion of the overall cost of the display, ranging from 30% to 70%.

How to identify the pros and cons of LED display beads?

1. Look at the solder joints. The LED strips produced by the regular LED strip manufacturers are produced by SMT chip technology, using solder paste and reflow soldering process.

2. Look at the quality of FPC. FPC is divided into two types: copper and rolled copper. The copper foil of the copper-clad board is protruding. If you look closely, it can be seen from the connection between the pad and the FPC.

3. Look at the cleanliness of the surface of the LED strip. If the LED light strip produced by SMT process is used, the cleanliness of the surface is very good, and there are no impurities and stains.

4. Looking at the chips and production process of LED lights, you can’t tell the difference with your eyes. You need to use aging equipment and testing equipment. If you put several manufacturers’ LEDs on the aging meter and use high current to aging for 24 hours or longer Over time, you can measure the brightness of LEDs from several manufacturers to see which LED luminous intensity attenuation is the smallest, and the quality with the smallest attenuation is the best.

What are the effects of LED lamp beads on LED display?

1. Perspective

The viewing angle of the LED display is determined by the viewing angle of the LED lamp beads. At present, most outdoor displays use elliptical LEDs with a horizontal viewing angle of 100°and a vertical viewing angle of 50°, while indoor displays use SMD LEDs with a horizontal and vertical viewing angle of 120°. The display screen on the highway generally uses 30° because of its particularity; a round LED with a viewing angle is sufficient. Some high-rise display screens have higher requirements for vertical viewing angles. Viewing angle and brightness are contradictory to each other, and a large viewing angle will inevitably reduce brightness. The choice of perspective needs to be determined according to the specific purpose.

2. Brightness

　　LED brightness is an important determinant of the brightness of the display. The higher the brightness of the LED, the greater the margin for the use of current, which is good for saving power and keeping the LED stable. LEDs have different angle values. When the brightness of the chip is fixed, the smaller the angle, the brighter the LED, but the smaller the viewing angle of the display. Generally, a 100-degree LED should be selected to ensure a sufficient viewing angle of the display screen. For displays with different dot pitches and different viewing distances, a balance should be found in brightness, angle, and price.

3. Failure Rate

　　 Since the full-color display screen is composed of tens of thousands or even hundreds of thousands of red, green, and blue LED, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to industry experience, the failure rate between the start of assembly of the LED display and the 72-hour aging before shipment should be no more than three ten thousandths (referring to the failure caused by the LED lamp beads itself).

4. Antistatic ability

　　LED is a semiconductor device, which is sensitive to static electricity and can easily cause static failure. Therefore, the antistatic ability is very important to the life of the display. Generally speaking, the failure voltage of the human body electrostatic mode test of the LED should not be lower than 2000V.

5. Life

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

　　LED devices account for 70% of the price of LED displays, so LED devices can determine the quality of LED displays. my country is not only a major producer of LED devices, but also a gathering place for LED display manufacturing. The high technical requirements of LED displays are the future development trend. The high quality requirements of LED displays are not only about the trend of LED display manufacturers, but also the development of LED display device manufacturers. From the control of LED devices, China will promote China's transformation from a large LED display manufacturing country to an LED display manufacturing powerhouse.

6. Attenuation Characteristics

LED display screens will appear brightness decline and display color inconsistency after a long period of work, mainly due to the brightness attenuation of LED devices. The attenuation of LED brightness will reduce the brightness of the entire screen. The inconsistency of the attenuation amplitude of the red, green and blue LED brightness will cause the color of the LED display to be inconsistent, which is the phenomenon that we often say that the display is spent. High-quality LED devices can well control the brightness attenuation range. According to the standard of 20mA lighting at room temperature for 1000 hours, red attenuation should be less than 2%, blue and green attenuation should be less than 10%, so blue and green LEDs should not use 20mA current when designing the display, preferably only 70% to 80 % Of rated current.

　 The attenuation characteristics are related to the characteristics of the red, green, and blue LED. The current, the heat dissipation design of the PCB board, and the ambient temperature of the display screen all affect the attenuation.

7. Size

　　 The size of the LED device affects the pixel point distance of the LED display screen, that is, the resolution. 5mm oval lights are mainly used for outdoor displays above P16, 3mm oval lights are mainly used for outdoor displays of P12.5, P12, P10, and 3528 SMD LEDs are mainly used for indoor displays of P6 and P8. 2020-type SMD LEDs are mainly used for indoor displays such as P2 and P3. Under the premise that the dot pitch is constant, the size of the LED device can increase, which can increase the display area and reduce the graininess, but because the black area is reduced, the contrast will be reduced; on the contrary, the LED size is reduced, the display area is reduced, and the graininess is increased. , The black area is enlarged, increasing the contrast.

8. Consistency

The full-color display is composed of countless red, green, and blue LEDs. The brightness and wavelength consistency of each color LED determines the brightness consistency, white balance consistency and chromaticity of the entire display. sex. Generally speaking, display screen 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 the device supplier through a spectroscopy machine. The consistency of voltage is generally not required.

　 Because the LED is angled, the full-color LED display also has angular directionality, that is, when viewed from different angles, its brightness will increase or decrease. In this way, the angle consistency of the red, green, and blue LEDs will seriously affect the consistency of the white balance at different angles, and directly affect the fidelity of the video color of the display screen. To achieve the matching consistency of the brightness changes of the red, green, and blue LEDs at different angles, it is necessary to strictly carry out scientific design in the package lens design and raw material selection, which depends on the technical level of the package supplier. No matter how good the white balance is in the normal direction, if the LED angle is not consistent, the white balance effect of the whole screen at different angles will be bad. The angle consistency characteristics of LED lamp beads can be measured with a comprehensive LED angle tester, which is particularly important for medium and high-end displays.

     At present, domestic lamp beads brands include National Star, Mulinsen, Hongsheng, Jingtai, Huaguang, etc