First. Introduction

Full color LED display is a new type of electronic media, in large size, high brightness, environmental adaptability has irreplaceable advantages for Hu make up a large size, large size outdoor graphics, video display, the main used in advertising media, stage set, building decoration, traffic information, sports venues and so on. With the LED chip technology, packaging technology and the rapid LED display manufacturing technology to enhance and further price drop, full-color LED display is cost-effective application across the threshold, was a huge market applications and demand. Such as lp156wh1-tla1 and lp156wh2-tlq2

Second, full-color LED display-specific options

Full color LED display is the most critical parts of LED devices. There are three reasons: first, LED full color screen machine in use is the largest number of key components, will use several thousand per square meter to tens of thousands only LED; second, LED display for determining the optical properties of the entire screen of the main direct impact on audience on the screen evaluation; third, LED in the display the largest proportion of overall costs, from 30% to 70%.

LED full color LED display such as lp173wd1-tla1 is the most critical components, the equivalent of a computer CPU. LED options have been decided more than 50% of the entire display quality. If you can not choose a good LED, display the other parts of the screen no matter how good the quality can not make up for deficiencies.

Special LED full color LED display quality and parameters can be reduced to the following five elements:

1, failure rate

As the full color display by a group of thousands or even hundreds of thousands of red, green, and blue LED pixels comprising the composition of the failure of any color LED display will affect the overall visual effect. In general, according to industry experience, beginning in the LED display assembly to the aging of 72 hours before shipping the failure rate should be no more than three ten thousandths (LED device itself that caused the failure).

2, anti-static capability

LED is a semiconductor device sensitive to static electricity, static electricity can easily lead to failure, it is anti-static capability is essential to the life of the display. In general, LED human static test failure mode voltage should not be less than 2000V.

3, attenuation characteristics

Red, green, blue LED are the working hours have increased as the intensity attenuation characteristics. Advantages and disadvantages of LED chips, auxiliary materials and packaging technology good or bad The level of the decay rate determines the LED. In general, the 1000 hours, 20 mA at room temperature after the test light, the red LED should be less than 10% attenuation, blue, green LED of the attenuation should be less than 15%. Red, green, blue attenuation consistency of the full-color LED display such as lp171wu1 great influence on the future of the white balance, thereby affecting the fidelity of the display screen.

4, brightness

LED brightness is an important determinant of the display brightness. The higher the LED brightness, the greater use of current margin of saving power, to maintain good stability LED. LED have different angles, the brightness has been set in the chip case, the smaller the angle, LED, the more light, but the perspective of the smaller screen. General should be chosen to ensure 100-degree LED display sufficient perspective. Different for different point spacing and line of sight of the display, should be light, angle and prices to find a balance.

5, consistency

Full color display is a myriad of red, green and blue LED pixels makes up the composition, and the brightness of each color LED, the wavelength determines the consistency of the brightness of the display consistency, consistency of white balance, color consistency sex. In general, the display device manufacturers asked suppliers to provide 5nm wavelength range and 1:1.3 in the brightness range of LED, these indicators can be adopted by device vendors spectrophotocolorimeter grading machine to achieve. Voltage makes the consistency of the general requirements.

As the LED is angled, so full color LED display such as b170pw07 also has a point of direction, that is, when viewed at different angles, its brightness will be increasing or decreasing. In this way, red, green and blue LED’s perspective will seriously affect the consistency of the consistency of different angles, white balance, directly affecting the fidelity of the color video display. To achieve red, green, and blue LED brightness variations at different angles, matching consistency, the lens in the package design, raw materials, rigorous scientific design choice, depending on the technical level of packaging suppliers. Even the best method to display the direction of white balance, if the angle LED consistency is not good, the whole screen effect of different angles of the white balance will be bad. The angle of the device features LED consistency point of view can be integrated LED tester measured, for middle and high display is particularly important.

Third, full-color LED display specific use:

High-quality LED also needs a good use and the environment, can be summed up using the following eight points:

1, anti-static

Display such as lp171wu1 assembly plant should have good anti-static measures. Special anti-static, anti-static flooring, anti-static soldering iron, anti-static table mat, anti-static ring, anti-static clothing, humidity control, equipment grounding (especially cutting machines) are all basic requirements, and regular tests to use static meter .

2, through wave soldering temperature and time

To be strict control of temperature and wave front through furnace welding time, suggestions are: preheat temperature 100 ℃ ± 5 ℃, the maximum does not exceed 120 ℃, and the preheating temperature rise for a smooth, welding temperature of 245 ℃ ± 5 ℃, welding time recommended no more than 3 seconds after furnace avoid excessive vibration or shock LED, until the restoration of normal temperature. Wave soldering machine to periodically test the temperature parameter, which is determined by the characteristics of LED, overheating, or fluctuations in temperature will cause direct damage to LED or LED quality risks, especially for small size, such as circular and oval 3mm LED.

3, the design current value

The nominal LED current is 20mA, maximum use of current general recommendation of not more than 80% of nominal value, in particular, the distance between the small screen, due to poor heat dissipation, but also reduce the current value.

Experience, as red, green, blue LED decay rate of the inconsistency, targeted reduction in blue, green LED’s current value, in order to maintain display consistency of the white balance after prolonged use.

4, mixed with light

The same color with different brightness profile of LED lights require mixing, or the law designed to plug in discrete light diagram inserted lamp, in order to ensure the full screen brightness of each color consistency. This process if a problem occurs, there will be displays of local brightness inconsistency, directly affect the LED screen display.

5, control the light and the vertical degree

For the-line LED for a sufficient time had furnace technology to ensure perpendicular to the PCB board LED. Any deviation will affect the already set a good LED brightness uniformity, color block appears inconsistent brightness.

6, thermal design

LED work may have a fever, high temperature will affect the decay rate and the stability of the LED, so the heat PCB board design, thermal design of the ventilation box will affect LED performance.

7, Weld Control

LED display LED is not lit in the event, they often have more than 50% probability caused by various types of Weld, such as the LED pin Weld, IC pin Weld, and Weld pin arrangement such as the mother. These issues need to strictly improve the process to improve and strengthen the quality inspection to resolve. Vibration test before leaving the factory also be a good test method.

8, driving circuit design

Display module on the drive circuit board arrangement of driver IC for LED brightness will also be affected. As the driver IC output current in the PCB board transmission distance too far, will make the transmission path of the pressure drop is too large, affecting the normal LED operating voltage leads to decrease in brightness. We often find that the LED display modules around the middle of the brightness lower than that for this reason. Therefore, the display brightness to ensure consistency, we must design a good drive circuit distribution.

These are the selection and use from the perspective introduced full-color LED display relevant knowledge, dedicated, full-color LED display is a system integration of products, need for LED packaging manufacturers and display applications in close collaboration with manufacturers to strengthen technological exchanges. China has now become the world’s manufacturing center LED display is closer to the LED display manufacturing power. So far, China Full Color LED package uses standard has been greatly improved, many indicators have been close to the level of Japanese firms, individual targets have been exceeded, this will greatly promote the development of China’s LED display.