Due to the limitation of the product structure, in order to reduce the good connection of the circuit when making the PCBA board. Will choose a combination of soft and hard PCB board.
Refers to the combination of FPC soft board and FR4 hard board in the same circuit called soft-hard combined board. In terms of PCBLayout design, there is a big difference between soft board design and hard board design.
Here are some relevant knowledge that needs to be paid attention to in the design of rigid-flex board.
"One" flexible zone circuit design requirements:
1. Teardrop shapes are often used between thick and thin lines to prevent sudden expansion and contraction of the line.
2. Use R angle, avoid 90 degree angle.
"Two" in the case of meeting electrical requirements. The pad needs to be the largest. The transition line between the pad and the trace should avoid 90 right angles, and the R angle should be used, and the toe should be added to the independent pad to strengthen the supporting effect.
"Three" Reliability: Add as many copper plates as possible to design, and add as many solid copper plates as possible to useless areas.
"Four" cover film window design
1. Add machine positioning holes, such as MARK, to improve alignment accuracy.
2. Window design needs to consider the range of glue flow. Usually, the window opening needs to be larger than the original design, and the specific size should be provided by ME.
3. Special mold design can be used for window openings in small areas with small spacing and dense areas: such as (rotating punching, jumping punching), etc.
Design of "Five" junction area
1. For the smooth transition of the line, the direction of the line should be perpendicular to the bending direction;
2. The wires should be evenly distributed in the entire bending area;
3. The width of the wire should be maximized in the entire bending area, and the transition area should not be designed with PTH as much as possible;
"six"Pay attention when there are air-gap design requirements
1. There must be no vias at the bending part.
2. Add protective copper wires on both sides of the line.
3. The connecting part of the line needs to be designed as an arc line.
4. Without affecting the assembly, the larger the bending area, the better.