The most critical component of full color LED display is LED light bulb.
For three reasons:
First, LED is the most used key device in the full-color screen, with thousands to tens of thousands of leds per square meter.
Second, LED is the main body that determines the display performance of the whole screen, directly affecting the viewer's evaluation of the display screen.
Third, LED has the largest percentage of total screen costs, ranging from 30 per cent to 70 per cent.
How to distinguish the lamp of LED display lamp
One: look at the solder spot. The LED lamp belt manufactured by the normal LED lamp manufacturer is produced by SMT patch and solder paste and reflow soldering process.
Second: look at the quality of FPC. The FPC is divided into copper and calcul copper. The copper foil applied to copper plate is convex, and the closer look can be seen from the joint of the welding disk and FPC.
3. Look at the cleanliness of LED light belt surface. If the LED lamp is produced by SMT process, its surface is very clean and can't see any impurities and stains.
4: look at the chip and production process used by LED lights. With your eyes is can't tell the difference, with aging equipment and testing equipment, if you put a few manufacturer of LED on aging instrument with large current aging 24 hours or longer, you again to measure the LED brightness of several manufacturers, look at the LED luminous intensity attenuation minimum, attenuation minimum that quality is the best.
The impact of LED light beads on LED displays
1, the Angle of view
The Angle of the LED screen is determined by the Angle of the LED light. To date, most outdoor display screen choose horizontal Angle 100 °; 50 ° and vertical perspective; Elliptical LED, indoor display, choose level is 120 ° from vertical; The strip LED Display on the highway 30 ° is generally selected due to its particularity; The circular LED of the Angle is enough. Some high - rise screens have higher vertical angles. The Angle of view and brightness are contradictory, the big Angle must decrease brightness. The choice of perspective needs to be determined by specific USES.
LED brightness is the determining factor for the brightness of the display screen. The higher the brightness of the LED, the greater the residual amount of the current, and the advantage of saving power consumption and keeping the LED stable. Leds have different angles, and the smaller the Angle, the brighter the leds, but the smaller the Angle of the display. A 100 degree LED should be selected to ensure sufficient viewing angles. A balance of brightness, Angle and price should be found for the screen with different spacing and different horizon.
Since the full color display is composed of tens of thousands or even hundreds of thousands of leds 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 efficiency of the LED display will not be higher than three parts per 10,000 (the failure caused by the light of the LED bulb itself).
4. Anti-static ability
LED is a semiconductor device, sensitive to static electricity, easy to induce electrostatic failure, so the anti-static ability is crucial to the life of the display screen. Generally speaking, the test failure voltage of LED is not less than 2000V.
Theoretical service life of the LED devices for 100000 hours, far more than the working life of the LED display other parts, so the right LED device quality guarantee, the working current, reasonable PCB thermal design, display production process is rigorous, the LED device is one of the most durable parts in screen machine.
LED devices account for 70% of the price of LED displays, so leds can determine the quality of LED displays. Our country is the production power of LED device, also is the place that LED screen makes a place. The high technical requirement of LED display is the trend of future development. The high quality requirements of LED display screen are not only about the trend of LED display manufacturers, but also the development of LED display device manufacturers. The switch from LED devices to the manufacturing of LED displays by LED screens in China is a shift in manufacturing power to LED screens.
6. Attenuation characteristics
LED display will appear after long work, the brightness drop and the color of the display color are inconsistent, mainly because of the brightness attenuation of LED devices. The attenuation of the LED brightness will reduce the brightness of the screen. The inconsistencies of red, green, and blue LED brightness attenuation will result in the inconsistency of the color of LED display, which is what we often call the display. High quality LED devices can control brightness attenuation well. By 1000 hours at room temperature light 20 ma standards, attenuation should be less than 2%, red, blue, green attenuation should be less than 10%, in blue, green LED display screen design as far as possible not to use when 20 ma current, had better use only 70% to 80% of the rated current.
In addition to the characteristics of red, green and blue leds, attenuation is affected by the use of current, PCB heat dissipation design, and ambient temperature of the display.
The size of LED devices affects the pixel distance of LED display, i.e. resolution. More than 5 mm elliptic lamp is mainly used for P16 outdoor display, 3 mm elliptic lamp is mainly used for outdoor P12.5, P12, P10 display, type 3528 SMD leds is mainly used for indoor display, P6, P8 type 5050 SMD leds is mainly used for P16, P12.5 half outdoor displays, etc. Under the premise of constant point spacing, the size of the LED device increases, which can increase the display area and reduce the grain sense, but because the area of black area is reduced, the contrast will be reduced. On the contrary, the size of the LED is reduced, the display area is reduced, the size of the particle is increased, the area of the black area increases, and the contrast is increased.
Full-color display screen is made up of thousands of red, green and blue leds Mosaic composed of pixels, each color LED brightness, the wavelength determines the whole screen brightness consistency, the consistency of the white balance consistency, color uniformity. In general, the manufacturer of display device vendor for 5 nm wavelength range and 1:1. The 3 LED brightness range, these indicators can be made of classification through the testing machine can achieve device supplier. The consistency of voltage is generally not required.
Because the LED has an Angle, the full-color LED display also has a directional orientation, which means that when viewed from different angles, the brightness is increasing or decreasing. In this way, the Angle consistency of red, green and blue leds will seriously affect the consistency of white balance in different angles and directly affect the fidelity of video color on the display screen. To be red, green, blue three kinds of LED brightness changes when matching consistency in different angles, encapsulated lens design, choice of raw materials is needed in the strict scientific design, this depends on the technical level packaging suppliers. If the Angle of the LED is not consistent, the white balance effect of the whole screen will be bad. The Angle consistency of LED lamp bead can be measured by LED Angle comprehensive tester, which is especially important for medium and high - grade display.