Rigid-flex circuit board

Rigid-flex circuit board is a special PCB circuit board that integrates soft board and hard board. It is made of hard board material FR4 and soft board material polyimide (PI).

The previous ordinary hard board was connected in three-dimensional space through connectors and cables. This connection method not only occupies space, but also has unstable structure and unstable performance. It is not suitable for the development of today's products towards precision, high performance and light weight. The trend of the flexible and rigid circuit board combines the advantages of the flexibility of the flexible board and the rigidity of the hard board. , Change the shape according to the space limit, realize the characteristics of small size and high performance.

Special attention should be paid to the design of the soft-rigid circuit board. When designing the connection between the soft board and the hard board, the distance between the via hole and the soft-hard junction of the soft-hard circuit board must be greater than or equal to 0.60mm. The line is less than 0.6mm, and the liquid medicine infiltrates into the soft board area during the wet process after pressing and drilling, which will contaminate the soft board.

The number of layers of the flexible and rigid circuit board, the minimum is 3 layers, conventional 4 layers, 6 layers, 8 layers, 10 layers, 12 layers..., there are conventional structure of flexible and rigid circuit boards, and there are also HDI structures Rigid-flex circuit board. Figure 1 below shows the stacked structure of a common 4-layer Rigid-Flex board; Figure 2 below shows the stacked structure of an 8-layer HDI Rigid-Flex board.

Figure 1: Normal4Layer-flexible-rigid board stack

figure 2:8layerHDIRigid-flex laminate