Samsung Patents a Camera Design That Folds Light to Slim Down Zoom Lenses

By Patentlyze Team · Updated Jul 3, 2026

Getting a powerful zoom lens into a thin smartphone requires some optical gymnastics. Samsung's latest patent defines the exact geometric rules for bending light inside a camera module so the whole stack stays compact.

How Samsung's folded-light camera fits into a slim phone

Imagine you want to fit a telephoto camera lens, the kind on a dedicated camera that sticks out several inches, into a phone that's less than a centimeter thick. The trick engineers use is to turn the light sideways: light enters the phone from the back, hits a mirror or prism, and bounces down toward the image sensor instead of traveling straight through. That lets the long optical path fold inside the phone's body.

Samsung's patent describes a specific camera module that does exactly this. It lays out two numerical rules, expressed as ratios, that govern how the lenses and the reflective element (the mirror or prism) should be sized and arranged relative to each other. Get the ratios right, and you get a module that's both optically sharp and physically small enough to slot into a slim device.

This kind of folded-optics or periscope design is already used in high-end Android and iPhone cameras for zoom lenses. Samsung's patent is essentially staking out a particular configuration of that idea, with tighter constraints on proportions.

How the TL/OTTL and Pin/Pout ratios shape the optics

The patent claims a camera module built from three main parts: a set of at least two lenses lined up along a shared optical axis, a reflective optical element (a prism or mirror) that bends the light at least once, and an image sensor sitting at the end of the bent light path.

The two key constraints are expressed as ratios:

• TL/OTTL between 0.1 and 0.6: TL is the physical length of the lens stack from front to back. OTTL is the total optical travel distance, counting both the straight-in path from the front lens to the mirror and the redirected path from the mirror to the sensor. Keeping TL/OTTL below 0.6 means the lens stack stays short relative to the full light path, which is what makes a folded design worthwhile.
• Pin/Pout between 1.25 and 10: Pin is how wide the optical member is in the direction the light exits (toward the sensor). Pout is how wide it is in the direction the light enters (from the lenses). A ratio greater than 1.25 means the prism or mirror spreads out more in the exit direction, shaping the optical member so it efficiently handles the redirected beam without taking up unnecessary lateral space in the phone.

Together these ratios define a design window where the module is geometrically balanced: enough room for the light to travel the distance needed for zoom, but constrained enough to fit inside a thin chassis.

What this means for Galaxy camera hardware

Periscope zoom cameras are now a standard feature on flagship phones, including Samsung's own Galaxy S and Z series. The challenge is that each new phone generation pushes for thinner bodies and tighter tolerances, which forces optical engineers to be increasingly precise about how every component is proportioned. A patent that formally defines acceptable ratio ranges for the lens-to-prism relationship is the kind of foundational IP that covers a broad range of physical implementations rather than one specific lens formula.

For Galaxy device buyers, this points toward continued refinement of Samsung's in-house telephoto modules. If the company can manufacture to these tighter ratio constraints at scale, the practical payoff is zoom cameras that are thinner without sacrificing image quality.

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