LED lamp beads used in the display field need to pay attention to the 8 parameters

LED lamp beads used in the display field need to pay attention to the 8 parameters

LED lamp beads, as the highest cost and largest component of LED display, play a leading role in the quality impact of LED display. Today we will introduce you why LED lamp beads are the most critical component of LED display and how to identify the advantages and disadvantages of LED lamp beads?

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

First, LED is the key device with the largest number of full-color screen, which will use thousands to tens of thousands of LEDs per square meter.

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

Third, LED in the display of the overall cost of the largest proportion, ranging from 30% to 70%.

How to identify the LED display lamp beads superiority and inferiority?

First, look at the solder joints. Legitimate LED strip manufacturers produce LED strip is produced using SMT SMD process with solder paste and reflow soldering process.

Second, look at the quality of FPC, FPC copper and calendered copper two, copper foil is convex, a closer look can be seen from the connection between the pad and the FPC.

Third, look at the cleanliness of the surface of the LED strip. If the use of SMT process production of LED strip, the surface cleanliness is very good, see what impurities and stains.

Fourth, look at the LED lights with the chip and production process, with the eye is not to see the difference, to use aging equipment and testing equipment if you put several manufacturers of LED on the aging instrument with high current aging 24 hours or longer, you then measure the brightness of several manufacturers of LED, see that led luminous intensity decay the smallest, decay the smallest that quality is the best.

LED lamp beads on the LED display what are the effects of

1, perspective

The perspective of the LED display is determined by the perspective of the LED lamp beads. At present, most of the outdoor display selected horizontal perspective 100 °;, vertical perspective 50 °; elliptical LED, indoor display is the choice of horizontal and vertical are 120 °; SMD LED. highway display due to its special nature of the general choice of 30 °; perspective of the round LED is enough. Some high building display vertical perspective requirements are higher. Angle of view and brightness contradict each other, large perspective will inevitably reduce the brightness. The angle of view needs to be selected according to the specific use to decide.

2、Brightness

LED brightness is an important determinant of the display brightness. the higher the LED brightness, the greater the margin of the use of current, to save power consumption, to maintain the stability of the LED is good. LED has different angle values, in the case of chip brightness has been set, the smaller the angle, the LED is brighter, but the display angle is smaller. Generally should choose 100 degrees of LED to ensure that the display sufficient perspective. For different point spacing and different viewing distance of the display, should find a balance point in brightness, angle and price.

3、Loss of efficiency

As the full-color display is composed of tens of thousands or even hundreds of thousands of groups of red, green and blue LED pixels, the failure of any color LED will affect the overall visual effect of the display. Generally speaking, according to industry experience, the failure rate should not be higher than three ten thousandths of a percent before the LED display starts assembling to aging 72 hours shipping (refers to the failure caused by the LED lamp beads themselves).

4, anti-static ability

LED is a semiconductor device, sensitive to static electricity, very easy to cause static failure, so the ability to resist static electricity is essential to the life of the display. In general, the LED human electrostatic mode test failure voltage should not be less than 2000V.

5、Life time

The theoretical life of LED devices is 100,000 hours, much longer than the working life of other components of the LED display, so as long as the quality of LED devices to ensure that the working current is appropriate, PCB thermal design is reasonable, display production process is rigorous, LED devices will be one of the most durable parts of the display machine.

LED devices account for 70% of the price of the LED display, so that LED devices can determine the quality of LED display. China is the production of LED devices, is also a gathering place of LED display manufacturing. LED display high technology requirements is the future development trend, LED display high quality requirements, not only about the LED display manufacturers towards, but also implicated in the development of LED display device manufacturers. From LED devices gate-keeping, to promote China's LED display manufacturing power to LED display manufacturing power change.

6, attenuation characteristics

LED display will appear after a long time of work brightness decline and display color inconsistency phenomenon, mainly due to the LED device brightness attenuation caused by. LED brightness attenuation will cause the display screen brightness reduction. Red, green, blue LED brightness attenuation amplitude inconsistency will cause the LED display color inconsistency, is what we often say the phenomenon of the display flower. High-quality LED devices can well control the brightness decay amplitude. By 1000 hours of room temperature light 20mA standard, red attenuation should be less than 2%, blue, green attenuation should be less than 10%, so blue, green LED in the display design try not to use 20mA current, it is best to use only 70% to 80% of the rated current.

Attenuation characteristics in addition to the red, green, blue LED characteristics related to the use of current, PCB board thermal design, the use of the display environment temperature, etc. have an impact on the attenuation.

7、Size

The size of the LED device affects the pixel distance of the LED display, i.e., resolution. 5mm ellipsoidal lights are mainly used for outdoor displays above P16, 3mm ellipsoidal lights are mainly used for P12.5, P12, P10 outdoor displays, 3528-type SMD LEDs are mainly used for P6, P8 indoor displays, 2020-type SMD LEDs are mainly used for P2, P3 and other indoor display screen. In the premise of the point spacing remains unchanged, LED device size increases, can increase the display area, reduce the sense of grain, but due to the reduction of the black area, will reduce the contrast; On the contrary, the LED size decreases, reducing the display area, the sense of grain increases, the black area increases, increasing the contrast.

8、Consistency

Full-color display is composed of countless red, green and blue LED pixels spell, each color LED brightness, wavelength consistency determines the brightness consistency, white balance consistency, chromaticity 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, and these indicators can be graded by device suppliers through a spectrophotometric color separation machine. The consistency of voltage is generally not required.

As LED is angular, so the full-color LED display also has angle directionality, that is, when viewed at different angles, its brightness is incremental or decremental. In this way, red, green, blue three colors LED angle consistency will seriously affect the consistency of the white balance of different angles, directly affecting the display video color fidelity. To achieve red, green, blue three LEDs in different angles when the brightness changes match the consistency, the need for strict scientific design in the package lens design, the choice of raw materials, which depends on the technical level of the package supplier. Normal direction white balance and good display, if the LED angle consistency is not good, the white balance effect of the whole screen at different angles will be bad. LED lamp bead angle consistency characteristics can be measured by LED angle integrated tester, especially important for medium and high-grade display.