Samsung Patents a Recessed PCB Layout for Thinner Foldable Devices

By Patentlyze Team · Updated May 16, 2026

Getting two separate circuit boards to talk to each other across a mechanical hinge — without adding bulk or breaking when the phone folds thousands of times — is one of the nastiest unsolved problems in foldable phone engineering. Samsung's latest patent takes a quiet but practical swing at it.

What Samsung's foldable circuit board trick actually does

Imagine a book where the left and right halves each have their own brain, and those brains need to stay in constant communication every time you open or close the cover. That's basically what's happening inside a foldable phone — two circuit boards, one in each half, connected across a hinge that flexes constantly.

Samsung's patent describes a specific way to wire those two boards together. Each half of the phone has a metal support frame with a hole punched through it. A conductive cable runs through both holes to link the boards electrically. The clever part: one of those support frames has a shallow recess — a carved-out pocket — where part of the circuit board sits inside the frame rather than on top of it.

That might sound minor, but sinking the board into the frame instead of stacking it on top means the whole assembly can be thinner. You're using depth that was already there rather than adding new height to the device.

How the recess and through-holes route power across the hinge

The patent covers the structural arrangement of printed circuit boards (PCBs) — the green slabs covered in chips and traces that power everything in your phone — inside a foldable device with two distinct housings joined by a hinge.

Each housing contains its own PCB and its own rigid support member (think of this as the phone's internal skeleton, usually made from aluminum or stainless steel). Each support member has a through-hole — a precision-drilled opening — and a conductive connection member (likely a flexible cable or wire bundle) threads through both holes to bridge the two boards electrically.

The key structural detail is the recess in the first support member. Rather than the PCB sitting flat against the surface of the frame, a portion of it drops down into a machined pocket within the frame itself. This means:

• The PCB and the support member share vertical space instead of stacking additively
• The overall z-height (thickness) of that half of the device can be reduced
• The through-hole routing keeps the inter-board connection path short and direct

The design is essentially about packaging efficiency — fitting the same electronics into less physical volume, which is the central engineering challenge in any thin foldable.

What this means for foldable phone thickness and reliability

Foldable phones are still noticeably thicker than slab phones when folded, and that's one of the main reasons mainstream buyers hesitate. Every millimeter shaved from the internal stack directly impacts whether a device feels premium or chunky in a pocket. Samsung's Galaxy Z Fold series in particular has been on a multi-year thinness trajectory, and patents like this are the granular mechanical work that drives those gains.

For you as a consumer, this kind of filing suggests Samsung is still actively engineering the internals of foldables rather than just iterating on software. It's also worth noting that routing a conductive connection through structural frame holes — rather than leaving a cable dangling loose — could improve durability by reducing flex fatigue on the inter-board connection over thousands of fold cycles.

Editorial commentary on a publicly published patent application. Not legal advice.