When you encounter the problem of routing/short-circuiting of FPC flexible circuit boards, an effective method is to check under an optical microscope whether there is a line break. It can be seen that most of the route can penetrate electron-optical equipment, and only have encountered several instances at work. It is impossible to detect the problem of route rupture under an optical microscope, but the area where the gold finger is immediately measured with a three-meter watt-hour meter can indeed be used to measure the lead or intermittent contact.

In fact, there is no need to fuss over such results, because FPC is called flexible circuit board because it is flexible and can be bent. This is also the advantage and disadvantage of FPC. The disadvantage is that it can be bent because it may cause The copper foil circuit is broken.

Although the copper foil is soft, repeated bending or reciprocating fitness exercises or collisions are still likely to cause cracks. If it is a crack that can be seen by the human eye, it is very easy to deal with. In general, the cause of the rupture can be understood by the location, so that preventive measures can be taken.

The more difficult thing is that the gold finger at the end can measure the open/short circuit, but it can't find the broken part of the copper foil. If you can't find the part, you can't determine what caused the break. Generally, the following methods can be used:

1. First observe the fault line with a microscope, and find the location of the suspicious fracture to mark it.

2. If the microscope cannot find any suspicious fracture location, the line can also be divided into several small parts.

3. On both sides of the part where the route will be broken, or by section, use a knife to carefully cut the surface protective film of the flexible circuit board. It is best to take a new wallpaper knife or a carving knife, and then place the knife head Move up and down on the surface protective film to scrape off the surface protective film and expose the copper foil route underneath. In this way, three meters can be used to measure the circuit. Then gradually eliminate the possible break positions, and finally find the accurate break position of the copper foil wire.

4. If you are worried that this method may damage the copper foil circuit, you can also try to cut off the position where there is no copper foil beside the copper foil circuit, and then try to tear off the outer protective film to achieve the same purpose.