Publisher: Supplier of LED Display Time: 2022-07-28 14:28 Views: 321
Many customers understand that LED lamp beads (also called LED chips) are very important core components of LED display screens and play a vital role in performance, but in fact most people only know this concept, LED lamp beads. As the component with the highest cost and the largest amount of LED display, it plays a leading role in the quality of LED high-definition full-color display. Today, Liancheng sent a small editor to introduce why LED lamp beads are the most critical components of LED high-definition full-color display screens, and how to correctly identify the advantages and disadvantages of LED lamp beads?
1. The most critical component of the LED high-definition full-color display is the LED lamp bead?
(1)The LED high-definition full-color display is the most used key device in the whole machine, and thousands to millions of LEDs are used per square meter;
(2) LED is the main body that determines the optical display performance of the LED screen, which directly affects the audience's evaluation of the LED display;
(3)LED accounts for the largest proportion of the overall cost of the display, ranging from 30% to 70%.
2. How to identify the advantages and disadvantages of LED display lamp beads?
(1) Look at the solder joints. The LED light strips produced by regular LED light strip manufacturers are produced by SMT patch process, solder paste and reflow soldering process;
(2)Look at the FPC quality. FPC is divided into two types: copper-clad and rolled copper. The copper foil of the copper-clad plate is protruding. If you look closely, you can see it from the connection between the pad and the FPC;
(3) Look at the cleanliness of the LED strip surface. If the LED light strip produced by the SMT process is used, the cleanliness of the surface is very good, and no impurities and stains can be seen;
(4)Look at the chips and production processes for 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 machine and use high current to age them for 24 hours or more, you will measure the LED brightness of several manufacturers. , look at the LED with the smallest attenuation of luminous intensity, and the quality with the smallest attenuation is the best.
3. What are the effects of LED lamp beads on the LED display?
The viewing angle of the LED display depends on the viewing angle of the LED lamp beads. At present, most outdoor LED displays use horizontal viewing angles of 100°; elliptical LEDs with vertical viewing angles of 50°, and indoor LED displays use SMD LEDs with both horizontal and vertical angles of 120°. Due to its particularity, the display screen on the highway generally uses a circular LED with a viewing angle of 30°. Displays on some tall buildings require higher vertical viewing angles. The viewing angle and brightness are contradictory, and a large viewing angle will inevitably reduce the brightness. The choice of viewing angle needs to be determined according to the specific use.
LED brightness is an important determinant of display brightness. The higher the brightness of the LED, the greater the margin of the current used, which is good for saving power consumption 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. For displays with different dot pitches and different viewing distances, a balance point should be found in brightness, angle and price.
(3) Failure rate
Because the LED full-color display is composed of tens of thousands or even hundreds of thousands of pixels composed of three types 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 LED display should not be higher than 3/10,000 (refers to the failure caused by the LED lamp bead itself).
LED is a semiconductor device, which is sensitive to static electricity and can easily lead to static electricity failure. Therefore, the anti-static ability is very important to the life of the display screen. Generally speaking, the failure voltage of LED human body electrostatic mode test should not be lower than 2000V.
The theoretical life of the LED device is 100,000 hours, which is much longer than the working life of other components of the LED display. Therefore, as long as the quality of the LED device is guaranteed, the working current is suitable, the PCB heat dissipation design is reasonable, and the display production process is rigorous, the LED device will be the entire display screen. One of the most durable parts in a 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 big producer of LED display devices, but also a gathering place for LED display production. The high-tech 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, to promote China's transformation from a large LED display manufacturing country to a powerful LED display manufacturing country.
After the LED display works for a long time, the brightness will drop and the color of the display will be inconsistent, which is mainly caused by the brightness attenuation of the LED device. The attenuation of LED brightness will reduce the brightness of the entire display screen. The inconsistency of the brightness attenuation of the red, green and blue LEDs will cause the inconsistency of the color of the LED display, which is the phenomenon that we often say that the display is spent. High-quality LED devices can well control the magnitude of brightness attenuation. According to the standard of 20mA 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, try not to use 20mA current for blue and green LEDs in the display design, and it is best to use only 70% to 80%. % of rated current. In addition to the attenuation characteristics related to the characteristics of the red, green and blue LEDs themselves, the current used, the heat dissipation design of the PCB board, and the ambient temperature of the display screen all affect the attenuation.
The size of the LED device affects the pixel distance of the LED display, that is, the resolution. The 5mm oval light is mainly used for outdoor displays above P16, the 3mm oval light is mainly used for P12.5, P12, P10 outdoor displays, and the 3528 type SMD LED is mainly used for P6, P8 indoor led displays , 2020 type SMD LED is mainly used for indoor led display such as P2 and P3. Under the premise that the dot pitch is unchanged, the size of the LED device increases, which can increase the display area and reduce the graininess. However, due to the reduction of the black area, the contrast will be reduced; on the contrary, the size of the LED decreases, which reduces the display area and increases the graininess. , the black area increases, increasing the contrast.
The full-color display screen is composed of pixels composed of numerous red, green, and blue LEDs. The consistency of the brightness and wavelength of each color LED determines the brightness consistency, white balance consistency, and chromaticity consistency of the entire display screen. sex. 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 the device supplier through a spectroscopic color separation machine. The consistency of voltage is generally not required.
Since the LED is angled, the full-color LED display also has angular directionality, that is, its brightness will increase or decrease when viewed from different angles. In this way, the angular consistency of red, green, and blue LEDs will seriously affect the consistency of white balance at different angles, and directly affect the fidelity of the video color on the display. To achieve the matching consistency of the brightness changes of red, green and blue LEDs at different angles, it is necessary to strictly carry out scientific design in the design of the packaging lens and the selection of raw materials, which depends on the technical level of the packaging supplier. No matter how good the normal direction 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. The angle consistency characteristics of LED lamp beads can be measured by LED angle comprehensive tester, which is especially important for medium and high-end display screens.
The above is the impact of LED lamp beads on LED high-definition full-color display and how to correctly identify the advantages and disadvantages of LED lamp beads, which are organized by LCF Xiaobian for you. You are welcome to add and correct them. Friends can also contact us to send LED display manufacturers!