Publisher: Supplier of LED Display Time: 2016-11-05 Views: 1648
The most critical component of full-color LED full-color screen is LED lamp beads. There are three reasons:
First, LED lamp beads account for the largest proportion of the overall cost of the display, ranging from 30% to 70%. LED lamp beads are the most used key components in the full-color screen, and thousands to tens of thousands are used per square meter;
Second, LED lamp beads are the main body that determines the optical display performance of the entire screen, which directly affects the audience's evaluation of the display screen;
Third, LED lamp beads are the most used key components in the full-color screen machine, and thousands to tens of thousands of them will be used per square meter;
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 LED 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.
The viewing angle of the LED full-color screen depends on the viewing angle of the 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°, and indoor display screens use SMD LEDs with both horizontal and vertical angles of 120°. The display screen on the highway generally chooses 30° due to its particularity; the circular LED with the viewing angle is enough. 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.
3. Failure rate
Since the 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 from the start of assembly of the LED full-color screen to the aging 72 hours before shipment should not be higher than 3/10,000 (refers to the failure caused by the LED lamp bead itself).
4. Antistatic ability
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.
5. Attenuation characteristics
[LED full color screen] After working for a long time, the brightness will drop and the color of the display screen 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 full-color screen, which is the phenomenon that we often say that the display screen is spent. High-quality LED devices can well control the magnitude of brightness attenuation. According to the standard of 20mA lighting for 1000 hours at room temperature, the red attenuation should be less than 2%, and the blue and green attenuation should be less than 10%. Therefore, the blue and green LEDs should not use 20mA current when designing the display screen, 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 theoretical life of the LED device is 100,000 hours, which is much longer than the working life of other components of the LED full-color screen. 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 full-color LED screens, so LED devices can determine the quality of full-color LED screens. my country is not only a big producer of LED devices, but also a gathering place for LED full-color screens. The high-tech requirements of LED full-color screens are the future development trend. The high-quality requirements of LED full-color screens are not only about the trend of LED full-color screen 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 full-color screen manufacturing country to a powerful LED full-color screen manufacturing country.
The size of the LED device affects the pixel distance of the LED full-color screen, that is, the resolution. 5mm elliptical lights are mainly used for outdoor displays above P16, 3mm elliptical lights are mainly used for P12.5, P12, P10 outdoor displays, 3528 type SMD LEDs are mainly used for P6, P8 indoor displays, 5050 type SMD LED is mainly used for semi-outdoor display such as P16 and P12.5. 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.
Since the [LED full-color screen] is angled, the full-color LED full-color screen also has angular directionality, that is, its brightness will increase or decrease when viewed from different angles. In this way, the angle 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 the 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, the LED full-color screen manufacturer, 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.
[LED full-color screen] The 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 consistency of the entire display screen. Color consistency. 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.