When a competitive edge is no edge at all

In the fierce smartphone market, the drive for differentiation is pushing device manufacturers to the edge. After nearly two decades of constant design modifications, massive upgrades to camera capability, faster connection speeds, remarkable battery life improvements, and many other added features, the next battlefield in the smartphone (and wearables and tablets, too) market is delivering a bigger, better view. Consumers – especially gamers and video aficionados – want more surface area for their consumption of vibrant graphics. And brand owners are giving it to them.

In late 2024, Apple debuted the iPhone 16 Pro and iPhone 16 Pro Max with a bezel measuring a remarkable 1.41 mm / 1.36 mm. They have company: Oppo’s Find X8 boasts a bezel border of 1.45 mm, and the Xiaomi 15 comes in at 1.38 mm. A few tenths of a millimeter reduction from model to model or brand to brand may not seem like much, but to certain consumers, it is a big deal. It’s also a big deal to make it happen. When considering the design alterations, structural changes, and protection mechanisms required to achieve such minute frames without impacting any of the other necessary hardware, the feat is pretty stunning. 

The bezel, which is the frame of the phone (think picture frame), provides more than structural integrity alone. All the components on the front of the phone are within the confines of the bezel, except for the screen. The frame (bezel) houses essential electronics and cameras. Shrinking the bezel has tremendous impact on the entire smartphone structure, its durability (i.e., drop resistance), performance, and reliability. Plus, the device has certain usability size constraints. It needs to fit in your palm and back pocket, so increasing the overall footprint to allow a bigger screen is out. The only option is to decrease the width of the bezel. But it’s not as easy as reducing the frame size and making the display cover glass bigger. 

Simply put, this is the anatomy of a smartphone: a back cover, a mid-frame, a frame (bezel), a myriad of components, compact camera modules, etc., and the cover glass. To integrate all the functionality, cameras, and electronic packages required for today’s smartphones and reduce the bezel size, design changes are needed. Naturally, every brand owner has a different approach. 

Historically, most smartphone designs used a chip-on-glass (COG) approach, where integrated circuits (IC) were attached directly to the surface of the LCD screen. When connected to the flexible printed circuit (FPC), which is wrapped to the underside and connects to the motherboard, this creates a relatively wide ‘chin’ and a larger bezel. 

Moving the IC from the surface of the glass to the FPC in a chip-on-flex (COF) design, the FPC becomes the carrier of the chip and, thus, reduces the space required in the older COG method as the FPC can be folded behind the glass (LED or OLED). This then enables a narrower chin and the shrinking of the protective bezel.  

Finally, for flexible OLED displays, a technique called chip-on-plastic (COP) has emerged to enable a larger screen-to-body ratio. With COP, the chip is placed on a flexible plastic substrate, allowing improved screen module compression. Here, the chin is nearly eliminated to enable the achievement of a full screen.  

With this, smartphones can deliver a full-screen experience. However, to make these next-generation designs possible, a disruptive technology was necessary to balance design and durability. Immersive viewing cannot come at the expense of reliability and performance.