How Sony’s Stealthy Wearables Startup Built A Watch Out Of E-Paper

The FES started out as an experiment–here’s the story of how Sony’s under-the-radar wearables team brought it to market.


It’s one thing to test out an experimental material in the prototype phase. But producing that experiment on a mass scale is a whole different monster. Take the FES, an e-paper watch that Sony revealed in 2014. It’s taken two years to bring the timepiece to market, thanks to the industrial design challenge of using an existing material–e-paper–in an entirely new way.


E-paper is a genre of display technology that work similarly to actual ink on actual paper. That means you can read the display in bright sunlight, unlike standard electronic screens, and also uses less battery life–a major bonus for devices like watches. E-paper is composed of millions of tiny particles suspended between conductive film. The black particles carry a negative charge and white particles carry a positive charge. When electricity is applied to the display, it moves the particles around to create images or text on the display. It’s the same technology old-school Amazon Kindles used, but while e-paper has been used in tablets and signage, it hasn’t been widely applied in a wearable context.

The FES, which was designed by Fashion Entertainments—a startup within Sony—and the Tokyo-based design studio Takt Project, started out as a way to show how e-paper could be used in fashion to create products that are infinitely customizable, says Sony Fashion Entertainments’ Yuki Sugiue.

The FES demonstrates what e-paper can do in a very simple but novel way: The entire watch, including the band, is made up of a single piece of this conductive film, which bends to conform to the user’s wrist.

What sounds like a simple idea was actually the foundational design challenge, since e-paper is rarely used this way. “E-paper is usually used for flat, unbending displays, but it is very important to wear a watch comfortably,” Sugiue says. “The whole surface of the FES Watch’s strap is also made of e-paper, but the wearer can still open the buckle, put their hand through with ease and close the buckle, fitting the watch around their wrist comfortably. It is quite a natural thing for a watch, but this is not so easy to achieve for digital devices.” While Sony would not disclose specifically how it achieved the bendability, Sugiue says it was through careful study of the e-paper’s characteristics and learning how to manipulate it.

The watch conforms to the classic shape of a conventional watch—a round face and band—but it’s covered with an e-paper display, which has 24 different face patterns that wearers can engage at will by pressing a button on the watch’s side. “It’s something like a brand-new canvas, and is able to change its own skin to show a number of different characteristics,” Satoshi Yoshiizumi, Takt Project’s principal, says. “Therefore, it is like the ‘material of watch’ which has a silhouette of a watch, but stimulates your imagination and curiosity through trying various textures.” Shaking the watch activates the display, which goes “dark” if there’s no movement, conserving battery life.

Then there was the clasp–an unexpected design problem since puncturing an e-paper display is difficult and costly. The design team create a special clasp that allows users to easily adjust the size without damaging the display.


Other elements of conventional wristwatches, like the hinge connecting the face and band, don’t exist on the FES. Making that unusual form factor feel natural against the wrist, despite all the internal hardware, was a challenge. “A watch in general becomes comfortable to wear from the connection between the dial and the band,” Yoshiizumi says. “It was challenging to create the similar sense of wearing with a single material. Dealing with its flexibility and assembling such different element—like the inner structure and outer display—was challenging.”

E-paper also posed some new hurdles for the watch’s UX. While the FES isn’t complicated in terms of functionality, the e-ink display is “segmented,” meaning it’s designed to show specific numbers, letters, and shapes, rather than a “matrix” display composed of an array of pixels. Segmented displays have some inherent limitations on what types of graphics they can show, but the trade off is that they’re more flexible and bendable than a matrix display. Instead of having standard hour and minute hands, the design team developed an ultra-simple, pre-determined face design that displays the hour as numeric digits and the minutes as a rotating hand, ensuring that the user never notices those graphic restrictions.

Meanwhile, the simplicity of the display technology inspired some fun UX flourishes. For example, minimalists will rejoice at the watch’s ability to go from stealth mode to full-on display by simply shaking their wrist thanks to an accelerometer inside. Still, they’re not completely satisfied with the display technology. “We worked on the product planning of FES Watch around spring of 2014, and the flexibility of the segmented type was better than the matrix type at that time—that’s why we selected to use it,” Sugiue says. “Looking ahead, we’d like to evolve the product with the matrix type to offer more choice and freedom in design.”

The idea with the FES wasn’t to invent an entirely new paradigm for smartwatches. It was to show how an existing material could be re-appropriated by a different industry to create delight in users. “Our vision to deliver greater freedom and pleasure to fashion with the technology is not in the direction of creating extraordinary items with eccentric form factors,” Sugiue says. “Rather, our choice in applying the technology to fashion was to deliver a new experience to a familiar item. What we aimed to create is a next-generation watch in which users can choose its design any time—a new standard for a future where all fashion is digitized.”

Find it at for $300.

Photos: via Sony

About the author

Diana Budds is a New York–based writer covering design and the built environment.