Samsung Patents a Two-Piece Smart Ring That Shines Light Through Your Finger
Most health-tracking rings shine a light and catch its reflection off your blood vessels. Samsung's new patent flips that idea — literally sending light all the way through your finger from one ring to another.
What Samsung's two-ring health sensor actually does
Imagine holding a tiny flashlight against one side of your finger and measuring how much light comes out the other side. That's roughly what Samsung is describing here. One ring sends light into your finger; a second ring, magnetically clipped on opposite, catches whatever light passes through.
The two rings snap together with magnets, so you can wear them as a pair on the same finger. Because the light has to travel through your tissue and blood vessels to reach the second ring, the device can pick up much more detailed health data than a sensor that only reads the surface reflection — think oxygen levels, heart rate, and potentially more.
This is a meaningfully different approach from the single-ring sensors on the market today. It's similar to the clip-on pulse oximeters your doctor might put on your fingertip, but reimagined as something you'd actually wear all day.
How light travels through your finger between the two rings
The patent describes a wearable made of two separate rings designed to sit on the same finger, one on top and one on the bottom (or facing sides), held together by built-in magnets.
The first ring contains a light-emitting sensor — a small LED or similar source that fires light toward the finger. The second ring contains a light-receiving sensor that sits on the opposite side of the finger and captures whatever light has passed through the tissue. This is called transmittance-mode photoplethysmography (PPG) — as opposed to the more common reflectance-mode, where a single sensor both emits and detects light bouncing back off the same surface.
Because transmittance-mode sends light through the body, it captures a stronger and cleaner signal. Blood vessels, oxygen levels, and the rhythm of your heartbeat all affect how much light makes it to the other side, giving the sensors richer data to work with.
The magnetic coupling means the second ring is detachable — you could remove it when not needed, or the design could allow for different sensor modules to be swapped in. The patent notes that both housings work together so the light path between them is preserved even through the finger.
What this means for the future of Samsung's Galaxy Ring
The current generation of smart rings — including Samsung's own Galaxy Ring — uses reflectance-based sensors, which are simpler but inherently noisier. A transmittance design could improve the accuracy of blood oxygen (SpO2) readings significantly, which is one of the weakest spots in today's consumer wearables. Clinically accurate SpO2 tracking has been a longstanding challenge for wrist and finger wearables alike.
If Samsung can miniaturize this well enough for everyday wear, your next smart ring could deliver readings that are meaningfully closer to what a hospital-grade pulse oximeter provides. That matters most for people managing sleep apnea, cardiovascular conditions, or fitness recovery — but it would be a genuine step up for anyone tracking their health passively throughout the day.
This is one of the more genuinely interesting smart-ring patents to come out recently. The two-piece transmittance design solves a real, known problem with current wearable health sensors rather than adding a gimmick. Whether Samsung can make it comfortable and practical enough for daily wear is the real question — but the underlying idea is sound and the hardware concept is novel enough to be worth watching.
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Editorial commentary on a publicly published patent application. Not legal advice.