Inside an OLED Display

Look inside an OLED display by clicking on the names of each component.

Scientists at the Eastman Kodak company first created a dual-layered OLED display in 1987. But the first commercial application of an OLED display came in 1997, when one was used in a car audio screen made by Japan’s Pioneer Corporation.

The key breakthrough of OLED technology was the discovery that when electricity is applied to certain organic materials, these materials emit light, eliminating the need for the backlight and layers of filters required by LCDs. OLEDs thus have several advantages over LCDs: thinner structure, superior contrast ratio, higher luminance, wider viewing angles, faster response rates, and lower energy consumption.

OLED technology is divided into two main types: passive matrix (PMOLED) and active matrix (AMOLED). The key difference is that AMOLED includes thin film transistors (TFTs) that manage the pixels to allow for much higher resolution and virtually no limitation in screen size. First commercialized in 2003 by a joint venture between Eastman Kodak and Sanyo Electric, AMOLED has become the preferred OLED type for most high-end consumer electronic devices.

Samsung became the first company to use an AMOLED display on a mobile phone in 2007, the same year that Apple launched the iPhone. Subsequent AMOLED advancements focused on producing larger and more flexible displays for both televisions and smartphones. The OLED display is also typically the most expensive component of a smartphone—for example, it represents about 30% of the total production cost of an iPhone X.

Encases the display panel for protection. Usually combined with a touchscreen sensor layer to allow for capacitive functionalities. The cover glass for OLED smartphones is predominantly supplied by Corning.

Contains the organic materials that emit light and consists of four parts. Each organic material layer is microscopic, about 1/200th the thickness of a human hair. Various methods are used to apply these layers into different patterns, including ink-jet printing.

  • Cathode – Discharges electrons into the emissive and conductive layers below.
  • Emissive polymer layer – Composed of polymers and organic compounds that react to the electrons.
  • Conductive polymer layer – Composed of highly conductive organic compounds through which the electrons flow.
  • Anode – Receives and stores the electrons originally discharged from the cathode.

Protects the organic materials from damage. For rigid displays, encapsulation is usually made of specialty glass that requires a hermetically tight seal to prevent moisture and oxygen from damaging the OLED materials. For flexible displays, the encapsulation is usually made of plastic, although glass is still used in the manufacturing process.

Forms the base of the display panel, which contains millions of thin film transistors. The substrate is usually made of glass, although there are increasing pushes to use different materials.

Activates the massive number of pixels in the display panel to produce accurate images and faithful colors based on input signals. For a typical smartphone, the IC driver processes between 3 million and 4 million pixels.

*IC driver isn’t shown in the main graphic because it is usually folded into the display.