Analysis of the causes of LED screen lamp bead failure

Analysis of the cause of the LED screen lamp bead failure. The LED screen is composed of countless light-emitting diodes. Each LED lamp bead is neatly arranged and welded on the LED module of different specifications. The previous outdoor LED screen is a direct-plug structure, and there are few cases of false welding. , At present, the outdoor and indoor LED screens all use the lamp beads of the SMD structure, and due to the structure, there will be a phenomenon of virtual welding. The advantage of the SMD lamp bead is still greater than that of the in-line structure. The consistency of the LED screen of the SMD structure is very good. Since the red, green and blue are packaged in the same transistor, the high and low errors can be small due to the particularity of the structure, so the delicate process will Make the luminous wavelength band more precise, so that the LED screen will achieve the advantages of consistent color, large angle, and small spacing. How to solve the problem of virtual welding of LED lamp beads, let's analyze it in detail below.

Dead light detection method caused by virtual welding: a relatively simple but quite effective way to identify LED dead lights is to heat the lights that are not on. We heat the LED lead wires of some unlit LED lamps to 200-300°C, remove the fire source, and connect the LEDs with a 3-volt button battery according to the positive and negative poles. Reduce the LED light from bright to off, which proves that the LED light is soldered. The reason why heating can light up is to use the principle of metal thermal expansion and cold contraction. When the LED lead is heated, it expands and elongates to connect with the internal solder joint. At this time, when the power is turned on, the LED can emit light normally. As the temperature drops, the LED lead shrinks. Return to the normal temperature state, disconnect the internal solder joints, and the LED light will not light up. When this happens, it means that the dead light is caused by weak soldering.

Analysis of the causes of dead lights and precautions: 1. The negligence of a certain link in the packaging process is the cause. The cause of the dead lights of LEDs is mainly caused by the negligence of the staff. If the staff accidentally dot more or less silver glue (for single-solder chips), it will not work. Too much glue will return to the gold pad of the chip, causing a short circuit, and the chip will not stick firmly if it is missing. , Welding process, the temperature is generally 280 ° C is the best, the pressure, time, temperature, and power of the gold wire ball welding machine must be properly coordinated, otherwise, the chip will be easily crushed if the pressure is too high, and the chip will be easily broken if the pressure is too small. 2. Solve the problem of static electricity causing damage to the LED chip, causing the PN junction of the LED chip to fail and lead to dead lights.

The PN junction failure of the LED chip leads to dead lights. Most of the dead lights are caused by the workers themselves. The amount of static electricity on the human body is related to the clothes of different fabrics worn by people and the physique of each person. In autumn and winter, we take off our clothes at night. It is easy to see the discharge phenomenon between clothes, so you should wear anti-static clothing when working, and wear an electrostatic ring. The electrostatic ring should be well grounded. There is a kind of electrostatic ring that does not need to be grounded. The anti-static effect is not good, so it is recommended not to use it. For this kind of product, if the staff violates the operating procedures, they should receive corresponding warning education, and also play a role in notifying others. The above is the analysis of why LED screens have dead lights. Raw materials and craftsmanship are necessary conditions to ensure the production of high-quality LED screens. It is recommended that users choose better quality products to avoid problems when choosing LED screens. Unnecessary after-sales problems. .