The quality identification method of LED advertising exposed light source.

With the continuous expansion of the market of exposed lamps, the audience's demand for products is constantly improving. The purchasing personnel of the advertising company should also keep learning and understanding the industry information and professional knowledge, and better grasp the quality of the products.

1. Raw material structure and its performance.

1. Chip manufacturers: Japan, Japan, CREE, HP, OSRAM, Taiwan crystal circle, light lei, guangji, etc. The majority of China's LED light source products are produced in Taiwan and domestic brands. This is related to manufacturer positioning, market quotation and policy. Chip manufacturers differ generally in their stable performance. The world's top chip makers such as cory, osram and Japan have fixed target markets, such as high demand for defense and medical care. These chips are not cost-effective if they are made of modules and lamps.

2. The size of the chip is the size of the chip: at present, the size of the application of advertisement light source chip mainly includes: 9MIL, 10MIL, 12MIL, 14MIL\, 8*15, 9*15, 10*16, 10*23, 9*26, etc. In the same chip, the larger the size, the higher the brightness, the stronger the carrying capacity, the better the stable performance, and of course the higher the price.

3. LED life: life is also the best LED is only about 50000 hours, the LED chip, as a result of the packager in advanced production equipment used in difference, technical differences, different packaging format, management, and the difference of users use way, cause the life is not the same. Patch LED, life can reach 50,000 hours; Piranha LED, which can last up to 30,000 hours, direct LED, with a life expectancy of 10,000 hours. Of course, as chips and encapsulation technology progress, the data will improve.

4. Quality of the circuit board: the quality of the circuit board will have an important influence on the life of the LED. The circuit board is divided into aluminum plate, glass fiber board, half glass fiber board and board. Aluminum is the best quality, the heat dissipation is the best, but the cost is too high, domestic manufacturers generally only use in the high power LED products. The module and the exposed lamp manufacturers generally use cardboard, half glass fiber and glass fiber board.

Two: identify module and exposed lamp string method.

Just looking at the appearance can't determine the quality of the product, so some simple actions are needed to identify it:

1. Brightness: keep the acrylic sheet of milk white closely to the same number of modules or exposed lights and then slowly lift the small distance to see whether the brightness of the lamp can meet its own requirements.

2. Compared with the current size: white light theory, general straw hat, man-eating fish lamp bead < = 18 to 20 ma, SMD lamp beads < = 20 to 25 ma, for current high, such as 25 to 40 ma module and led twinkle light, I think the user should consider its stability. In practice, some of the signboards have just begun to be bright, and for a while, the length is a year, and the short three to five months become dim and dark, especially white light; The reason is that the light is too big, and the fundamental reason is that the current is too large.

3. Whether the luminescence is uniform: when observing white light, must pay attention to whether or not to appear chromatic aberration, the acrylic sheet that can use milky white is covered above will be observed. Color difference is the most important part to distinguish the quality of white light, and it is also one of the most important causes of price difference. A white light sign inside, some place appear cold white, some is white, some warm white, even appear red, purple, blue wait, look like a big flower face. This is the result of chromatic aberration or severe light failure; This is because there is no separation or separation of reasons.

4. Wire material identification: silicone sleeve, containing copper wire, copper, copper wire, high purity and flexible wire, this is the best wire. The silicone sleeve is able to withstand long periods of oxidation. The copper can also prevent copper wire from oxidation and make the wire soft, and copper wire can pass more current without being burned by the large current. The most direct way is to remove the skin and count the number of cores! With 11 cores, 14 cores, 15 cores, 17 cores, 19 cores and even more than 20 cores, of course, a lot of cores are good. You can also measure the voltage difference between the access power supply and the tail.

5. Luminance Angle: the same brightness, the Angle bigger the better, at present Angle is generally in 160-180 degree. The Angle is big generally need big chip to make, some manufacturers are to pursue brightness, the Angle achieves 120-140 degree. Now the market requires the light to be seen on the side, the light side of the light is not visible on the side of the light.

6. Lamp bead temperature: after lighting a period of time, touch the bead with your hand, the temperature is very high and even the hot hand will not have low temperature stability. You can also look at the circuit board, which is usually better than the cardboard module.

7. Fabrication process: how bright the solder is, whether it is full or not, whether there is no welding, which is serious is virtual welding. After a certain period of time, there will be a contact problem. This affects heat dissipation and signature stability. Such subsequent maintenance would be cumbersome. At present, most of the small advertising light source manufacturers are manual welding, and the proficiency of the workers directly affects the quality.

8. Waterproof treatment: as for the waterproof treatment of the exposed lamp, it is important to see whether there is glue cover outside the PCB board. It is easy to identify and remove the skin. Because of the competition of the products, many factories do not do three defense against circuit boards and components. Of course, in a short period of time is no problem, over time the shell of PVC will be corrosion of the circuit board and components.

9. PVC shell: the better shell can protect against uv, flame retardant, antifreeze and heat resistance. More transparent glue or PVC gum is generally good quality. The PVC rubber sleeve of exposed lamp if the elasticity is not good, the transparency is not high, it is possible to reuse the water mouth or the quality of the PVC.

3. The identification method of the whole color series products.

There are dozens of IC and components in the whole color series. There are dozens of IC, different IC performance, stability and price, which can lead to different quality and cost of finished products. Currently, IC is commonly used in the market:

LPD6803, D705, 1101, 6909, 6912, LPD8806, LPD8809;

UCS6909, UCS6912, UCS7009, UCS5903, UCS1903, UCS1903, UCS1912, UCS1912, UCS3903;

TM1803, TM1804, TM1809, TM1812, TM1903, T M1904, TM1909, TM1912;

DMX512, WS2801, WS2803, WS2811, DS189; TLS3001, TLS3002, TLS3008;

P9813, SM16716, BS0901, BS0902, BS0815, SM16726, SM16711;

Each IC has its own advantages and customers, and it can be judged from the following tests:

1. In the case of the failure of the 12V power supply, the IC will not be burned for a short time, and this will often happen during installation. At present, some power supply in the market is less stable, and the instantaneous voltage will sometimes break through 7.5V or even higher, resulting in the burning of IC.

2. In the case of 5V power supply, it will not damage the IC if the positive and negative polarity is reversed, the positive and negative electrode short circuit, the signal line is misconnected to 5V.

3. IC can work under low and 5V power supply. Because the power supply will decay in use.

4. If the power supply voltage fluctuates from 3V to 11V, it will burn the IC. Some power supplies have poor voltage stability, especially in the use of full color lamps, which often change power due to the image changes.

5. Whether the light is on when there is no access to the controller signal. It is better to light the lamp because it is impossible to judge whether the power supply is properly connected during installation. In the application, the lamp is out when the IC fails, and many users will not accept it.

Currently on the market of IC has 32 gray, gray, gray and gray level 4096, 1024 256 commonly used 32 gray and gray both 256, 32 gray products mature at present, the signal transmission power demand is not high, suit to do full color words, 256 grayscale products rich color order but higher requirements on power supply and signal transmission, easily influenced by voltage resulting in failure of IC and signal transmission difficulties, suit to do full color. So, when choosing full color lamp string, want to have an understanding to the IC that manufacturer USES, especially when use quantity more full colour lamp, otherwise maintenance is more troublesome.

And, of course, a good IC can only guarantee the stable life and color output, to appear good effects, light bead is also very important, want to make sure the light bead chip, the greater the size, the higher brightness, the stronger the bearing capacity, stable performance, the better, and chip size small and easy for dead lamp brightness difference; Secondly, it is necessary to test whether the RGB brightness and band are consistent, especially in yellow and purple, and the color difference will be distorted and distorted in color performance.

The market of blue view LED advertising light source will become more widely used as the LED chip matures. China's urbanization construction, urban landscape lighting is also constantly developing, whether the light source manufacturer or construction manufacturer, quality and cost control is the eternal theme. The market of LED lighting is unlimited, and the life of the city will be changed by the LED.