The document outlines different types of flexible circuit designs, including single-sided, double-sided, sculptured, and multilayer circuits. Each type serves distinct purposes, with varying layers and conductors, enhancing flexibility and performance in electronic devices. Notably, single-sided and double-sided circuits are the most commonly used, while sculptured circuits are unique, tailored to specific electronic device requirements.

1. Types of flexible circuit design
A flexible printed circuit comprises of multiple outlines of conductive traces that are bonded on a
base i.e. a flexible substrate. Flexible circuit boards are enabled to an extended freedom when it
comes to the packaging geometry. Even after providing maximum flexibility with the geometry it
retains the accuracy density and repeatability of printed circuit. A conventional flexible circuit
board is built up of ordinary PCBs and round wire, both of them complementing each other.
They count in as substitutes for wires and wire assemblies, in-turn saving costs and providing a
better quality of performance.
There are a few different types of flexible circuit board construction designs; they vary according
to the purpose they are supposed to serve.
Here are some basic types of flexible circuit boards:
Single-sided flexible circuit
Single-sided flexible circuits comprise of only one conductor layer, this layer is either made of
metal or conductive polymer on a flexible dielectric film. The component execution features are
only available from one side. The holes are created in the base film to allow the component leads
to pass to provide interconnection. This is usually done by the method of soldering. Single sided
flex circuits do not require protective coatings like cover layers or cover coat, they can be
fabricated with or without their presence. Even if not required, the use of a protective coating
above circuits is a common practice to ensure extra security.
Double-sided flexible circuit
When it comes to double-sided flexible circuits, it is well stated by the name that they have two
conductor layers unlike the single-sided flex circuit. The fabrication of these circuits can take place
with or without holes; the plated through hole variation is much more generic. The circuits that
are constructed without plated through holes, the association features are accessible only from
one side. A double sided flex circuit can be fabricated with protecting cover layers in one, both or
neither side of the finished circuit. In a common practice, the protecting layers are added on both
sides of the flex circuit. A major benefit of double sided circuits is that it enables intersect
connections to be prepared very easily.
Sculptured flexible circuit
Sculptured flex circuits are quite different from the typical flexible circuit structures. The extensive
procedure involved in the manufacturing includes a multi-step etching method which leads to a
flex circuit with finished copper conductors. These conductors do not have a defined thickness; it
keeps varying throughout the length of the circuit board. Basically, the thin part is the flexible are
and the thick parts are the interconnection parts.

2. Multilayer Flexible Circuits
As the name suggests, these flex circuits have three or additional layers of conductors. These
layers are interconnected by means of plated through holes, even after this process, it is possible
to supply openings to access the lower circuit level features. The layers of the multilayer flex are
not mandatory to be laminated mutually; this could or could not be needed. It depends on the
usage of the circuit board. Irregular lamination is often found in cases where utmost flexibility is to
be achieved.
To sum it up, the above mentioned are the most common and well-known flexible circuit boards
out of the multiples types that are used in the electronic devices. Out of the above the sculptured
circuit is the most unique as it differs according to the requirement of the electronic device,
whereas single-sided and double-sided are the most commonly used circuit designs.