Effect of LED lamp on the LED display
LED lamp is the cost of components in the LED display the highest and largest amount, to affect the quality of the LED display plays a leading role. Below we are going to learn about LED lamp as LED display the most critical components, how to identify the advantages and disadvantages of LED lamp?
The key components of full-color display screen is LED lamp.
First, LED is the use of full color machine in the largest number of key devices, per square meter will use thousands to tens of thousands of LED;
Second, LED is the entire screen optical display performance directly affects the evaluation subject, the audience on the display screen;
Third, LED display in the overall cost in the largest proportion, ranging from 30% to 70%.
How to identify the advantages and disadvantages of LED display lamp
A look at the spot. LED lamp LED lamp with the regular manufacturers with using SMT SMD technology, used in the production of solder paste and reflow process
Two, look at the quality of FPC. FPC copper and rolled copper two, copper clad plate of copper foil is protruding, take a closer look can look out from the connection pads and FPC
Three, see the LED lamp with surface cleanliness. If the LED lamp produced by SMT technology, the surface cleanliness is very good, can not see what impurities and dirt
Four, look at the chip and production process of LED lamp, with the eyes do not see the difference, with the aging equipment and testing equipment if you put a few manufacturers of LED on aging instrument with high current aging for 24 hours or longer, you can go to the measurement of several manufacturers of LED brightness, see the LED light the intensity attenuation is the smallest, the best quality, the lowest attenuation.
What are the effects of LED on the LED display lamp
1, from the perspective of
LED display angle depends on the perspective of LED lamp. At present most of the outdoor display level angle of 100 degrees, 50 degrees; the vertical angle of the ellipse; LED, indoor display with horizontal and vertical is 120 degrees; the patch LED. The display on the highway because of the particularity of general 30 degrees; from the perspective of circular LED is enough. Some buildings display higher requirement on the vertical angle of view. From the perspective of brightness and mutually contradictory, perspective will inevitably reduce the brightness. From the perspective of choice according to the specific purpose to decide.
LED brightness is an important factor deciding the brightness of the display screen. LED brightness is high, the greater the current margin, to save power, good stability of LED. LED has a different angle, the chip brightness has been set, the angle is smaller, LED is bigger, but the visual angle of the display screen is small. General should choose 100 degrees to ensure enough perspective display LED. According to the different spacing and different distance of the display screen, should find a balance in brightness, angle and price.
3, failure rate
The composition of the pixel full-color display consists of thousands or even hundreds of thousands of red, green, blue three LED, invalidation of any color LED will affect the overall visual effect of display. Generally speaking, according to the experience, in the LED display to start assembling the aging 72 hours prior to shipment of the failure rate should not be higher than 3/10000 (refer to the failure of LED lamp itself causes).
4, antistatic ability
LED is a semiconductor device, static sensitive, extremely easy to cause the electrostatic failure, antistatic ability is very important to display life. In general, the test body static mode LED failure voltage should not be less than 2000V.
The theory of life of LED devices for 100000 hours, far more than other parts of the LED display's working life, so long as the LED device, quality assurance, suitable working current PCB cooling design, screen production process is rigorous, LED devices will be one of the most durable components in the display screen.
LED devices accounted for 70% of the proportion of the price of the LED display, so that the LED device can determine the quality of the LED display. Our country is the production of LED devices, is also a gathering place for making LED display. High requirements of LED display technology is the future trend of development, the high quality requirements of LED display, not only to on the LED display manufacturers, development is also implicated in the LED screen device manufacturers. The checks from the LED device, and promote the transformation of Chinese by LED display LED display manufacturing power to create powerful.
The LED display will appear after long time working and display color brightness decline is not the same phenomenon, mainly due to the attenuation caused by the brightness of LED devices. The brightness of the LED display screen brightness attenuation will cause the entire reduction. Red, green, blue inconsistent LED brightness attenuation inconsistencies will cause the LED display color, we often say that the phenomenon of flower display. High quality LED device can well control the brightness attenuation. According to 1000 hours at room temperature 20mA lit red standard, attenuation should be less than 2%, blue, green attenuation should be less than 10%, so blue, green LED in the display design as far as possible not to use 20mA current, rated current of only 70% to 80% of the best.
In addition, the attenuation characteristics and red green, blue LED itself characteristics, using the current PCB, plate design, display ambient temperature on impact attenuation.
The size of LED devices LED display pixel distance, namely resolution. OVAL LAMP 5mm is mainly used for more than P16 outdoor display, elliptic 3mm lamp is mainly used for P12.5, P12, P10 outdoor display, 3528 patch LED is mainly used for indoor P6 display, P8, type 2020 LED patch is mainly used for P2, P3 and other indoor display. In the premise of constant spacing, LED device size increases, can increase the display area, reduce the grain, but because the black area reduced, will reduce the contrast; on the contrary, the size of LED is reduced, reducing the display area, grain increased, black area increased, increase the contrast.
Full color display pixels together by numerous red, green, blue LED composition, consistency of brightness, wavelength of each color of the LED determines the display brightness uniformity, white balance, color consistency, consistency. In general, manufacturers require the supplier to provide the 5nm display device and the wavelength range of the brightness of the 1:1.3 range of LED, these indicators by component suppliers by spectrophotometric color grading machine to. The consistency of voltage generally do not require.
Because LED is a point of view, it has the same color LED display angle, namely from different viewing angles, its brightness is increasing or decreasing. So, red, green, blue three colors LED point of consistency will seriously affect the consistency of the different aspects of white balance, directly affect the fidelity of color video display. To achieve consistent matching red, green, blue three LED brightness in different angle changes, the need for strict scientific design in the choice of raw materials, packaging lens design, depending on the package supplier technical level. The normal direction of the white balance and good display, if the angle of the LED consistency is not good, the white balance effect of different angles of whole screen will be bad. Measured LED bulb angle consistency properties available LED angle tester, for high-end display, is particularly important.
There are many welding methods for LED lamp beads on the chip, and the following is one of the commonly used methods for reference. First, use an electric soldering iron to heat some soldering tin on the positive and negative electrode pads of the lamp bead (the soldering tin must not be too much, otherwise, the positive and negative electrode pads will be connected once heated with a hot-air gun), then use a hot-air gun to heat the positive and negative electrode pads at the same time, after the tin melts, use tweezers to place the positive and negative electrodes of the lamp bead on the corresponding pad.
LED is the light emitting diode, which is a semiconductor solid light emitting device that converts electric energy into light energy. Its core is the PN junction. In addition to the forward conduction, reverse cut-off and breakdown characteristics of the general PN junction, it also has the light emitting characteristics under certain conditions. Its structure mainly includes the following parts: lead, bracket, encapsulation glue, bonding wire, LED chip, solid crystal glue and phosphor. The discoloration failure of LED lamp bead is closely related to its material, structure, packaging process and service conditions. The following will analyze the causes of its discoloration through specific cases.
LED lamp beads are also called light emitting diodes. It has a wide range of applications. Its luminous colors include red light, emerald green light, yellow green light, yellow light, purple light, blue light, white light and orange light. The above is monochromatic light. It can also be made into two or three colors.
The gold wire used to package LED lamp beads contains more than 99.99% gold. It is produced by drawing gold from this material. In addition to 99.99% gold, this gold also contains less than 1% other trace elements. One of the core components of LED lamp bead packaging is gold wire, which is the bridge connecting the luminous chip and the welding point, and plays a decisive role in the service life of LED lamp bead. So how to identify the purity of gold thread?