Flexible circuit board used for LED lamp band and manufacturing method thereof

Abstract

A flexible circuit board used for an LED lamp band comprises a PET thin film layer. Front and reverse surfaces of the PET thin film layer are coated with a front surface insulation bonding layer and areverse surface insulation bonding layer, the front surface insulation bonding layer is bonded with a front surface line layer, and the reverse surface insulation bonding layer is bonded with a reverse surface line layer. The front surface line layer is provided with a front cover layer, and the reverse surface line layer is provided with a reverse cover layer. The front surface line layer and the reverse surface line layer are aluminum foils having certain ductility. The front cover layer and / or the reverse cover layer are provided with bonding pad layers. One reverse surface line layer is arranged on a back surface of a circuit board, which is made of a metal aluminum foil material. Two sides of a PET thin film are supported by the metal aluminum foils. Under high temperature and welding conditions, the circuit board does not expand and contract that cause deformation and is very flat. After a lot of practice, bad phenomena such as tombstoning, insufficient soldering and false soldering and the like of a component can be eliminated. A yield rate of the flexible circuit board after reflow soldering can reach 99% or above, which has a significant economic value.

Description

technical field [0001] The invention relates to the technical field of a circuit board and a preparation method thereof, in particular to a flexible circuit board used for an LED light strip and a preparation method thereof. Background technique [0002] The LED light strip refers to welding the LED lamp beads on the flexible circuit substrate by welding, and then connecting the external core wire to the power supply, so that the strip-shaped FPCB (Flexible Printed Circuit Board flexible printed circuit board) is energized and glows. It is shaped like a strip and can be bent into any shape, so it gets its name. Its components mainly include FPCB, SMD LED lamp beads, resistors, etc.; LED strips are generally divided into low-voltage strips and high-voltage strips. The low-voltage light strip uses a conversion box to convert 220V AC power into DC power supply below 12V, which is a safe voltage. The general length is 6-10 meters and is suitable for civil purposes. High-voltag...

AI Technical Summary

Problems solved by technology

The circuit board made through the above steps, because the plastic film is only supported by copper foil on one side, and the other side is exposed, it will undergo reflow soldering when attaching components, and the temperature is usually around 220°C. Under high temperature conditions, it is easy to cause the plastic film to shrink and deform. , resulting in poor soldering of patches such as virtual soldering, false soldering, and tombstones, which seriously affects the quality and will cause direct scrapping of circuit boards and electronic components, which will increase costs virtually. The expansion and contraction deformation of circuit boards is mainly caused by high temperature The expansion and shrinkage ratio of the PI, PET, PVC and other plastic film layers is inconsistent with that of the circuit layer and the insulating layer

[0005] Therefore, how to simplify the preparation process of flexible circuit boards for LED light strips, avoid defects caused by inconsistent expansion and contraction ratios, and reduce the production process of downstream customers are the main technical problems to be solved in this application

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