OLEDs and foldable screens

There’s a lot of hype right now over foldable phones with companies like Samsung, Microsoft, and Google each coming up with their own take on the concept. A departure from classic smartphone designs, foldable phones with fully interactive screens are attractive both for their novelty and their efficiency, allowing users to take more screen space with them without having to manage a bulkier device.

The key to making a flexible phone or similar device is designing a display that is capable of bending while delivering rendered images to the viewer. So how have screens made this leap? The key is the advancement of organic light-emitting diode (OLED) technology.

Most devices use liquid crystal displays (LCDs), which depend on a glass backing that supports millions of tiny pixels that can emit red, green, or blue light. This results in displays that are inflexible because glass cannot bend without breaking. By contrast, OLED displays use a mesh of organic compounds imprinted on a thin layer of plastic. Images are generated by pulsing electricity through this mesh and because OLED displays do not need any backlighting, they can generate a wider, more dynamic range of colors with greater contrast. OLED displays are a win-win as they produce a better quality image on a thinner screen, so many companies use it as an advertising point when their products use OLED displays.

Understanding their role in modern electronics is one thing, but how are OLED displays constructed? Simply put, OLED displays are made by sandwiching a carbon-based semiconductor layer (hence the “organic” in OLED) between two electrodes. When electricity is applied to the electrodes, the semiconductor layer emits light. Similar to LCD displays, the primary colors are still red, green, and blue, but rather than having discreet pixels emitting these colors, OLED displays have meshes of different organic compounds that emit light in these three colors. By layering these compounds in certain ways, OLED displays achieve more consistent and continuous regions of illumination. Finding the right chemical composition and physical arrangement for the organic layer are the main challenges in creating better, more cost-effective OLED displays.

OLED technology has come a long way given that we are starting to see them worked into consumer-grade smartphones and gadgets. However, for truly widespread use, the other components of electrical devices have to evolve with the display. Batteries, circuitry, and chassis are not easily made flexible, and when proper care is not taken, it can have disastrous consequences.

Despite the roadblocks ahead, the existence of foldable phones and other devices that effectively integrate flexible OLED displays into them is an exciting indication of what the future holds. With continued research and development, OLED displays will soon become the industry standard. In a world where we interact with screens so frequently, that just means we are headed towards a bolder, more crisply rendered future.