rigid-flex circuit for defibrillatorThe slide show below represents the artwork levels of an 8 layer rigid flex. Four layers are rigid layers and four are flexible. It is highly recommended to do a balanced construction. For example, in the circuit below, you will see 2 rigid copper layers on the top and bottom outside,  and 4 flex copper internal layers.

The application is for a defibrillator (medical device). You can see that there are connectors required on two different sides of the circuit. This circuit is carrying signals and power.