Available structures for Rigid Flex Assembly

There are numerous, different structures available. The more common ones are defined below:

Traditional rigid flex construction (IPC-6013 type 4) Multilayer rigid and flexible circuit combination containing three or more layers with plated through holes. Capability is 22L with 10L flex layers.
Asymmetrical rigid flex construction, where the FPC is situated on the outer layer of the rigid construction. Containing three or more layers with plated through holes.
Multilayer rigid flex construction with buried / blind via (microvia) as part of the rigid construction. 2 layers of microvia are achievable. Construction may also include two rigid structures as part of a homogeneous build. Capability is 2+n+2 HDI structure.