Things You Should Know About OLED Displays

By Mike PecoraroJune 2, 2016

OLED, or Organic Light Emitting Diodes, can be referred to as an extension of the conventional LED technology. It integrates the same concept of an LED, but is different in that each pixel in an OLED display is self-illuminating as opposed to the backlight-supported illumination in LCDs. Plus, instead of an array of individual LED bulbs, OLED uses a series of thin, light emitting films. This allows the OLED to produce brighter light while using much less energy in comparison to the existing LCD/LED technologies.

Moreover, the OLED is also lighter than the traditional LCD/LED technology. This is because it is composed of hydrocarbon chains rather than semiconductors that are laden with heavy metals like gallium arsenide phosphide. The “O” in OLED comes from its “organic’ characteristics.

Primary Composition of OLED

An OLED panel is essentially composed of four primary layers -

  1. The Substrate - Acts as the structural framework.
  2. The Anode - Draws the electrons
  3. The Cathode - Provides the electrons
  4. The Organic Layer - The layer is divided into a conducting layer, which provides the "electron holes" and the emissive layer, where the light is actually generated.

Two Major OLED Variants and Their Specialized Applications

OLEDs come in two different types that suits different levels of requirements for different kinds of devices. Let’s break them down for you:

Passive matrix OLED (PMOLED) - PMOLED is a popular application, especially in devices that have a static display pattern with relatively slow refreshes. It works by turning on voltage to specific areas of the film and leaving them on until the device refreshes its instructions. 

Active matrix OLED (AMOLED) - AMOLED is best suited for high-definition applications that demand fast refresh rates. It is a common feature in today’s smartphone screens or HD televisions. AMOLED displays actually require a thin film transistor back-plane, which allows the flexibility required for developing rollable, foldable, transparent display panel prototypes. 

Key Characteristics of OLEDs  

The OLED is unique for its wide array of benefits that include the following:

Energy Efficiency - Compared to traditional LED/LCD technologies, an OLED display is more energy efficient because it completely eliminates the need of any electronics and circuitry used to drive the LED backlight or the LCD shutter. In case of a LED screen, black is produced by fully closing the pixel shutter. This means, the backlight continues to shine without actually turning off. On the contrary, an OLED entirely turns the pixel off to produce the color black, thus saving energy in the process.

Enhanced picture quality - OLEDs incorporate their own color filters, hence it produces deeper blacks and a wider array of colors. The contrast is also significantly increased, due to the lack of a permanently-on back light. Over and above, an OLED also offers faster refresh rates and wider viewing angles as compared to traditional LEDs.

Lightweight and Durable - OLED displays are impressively light and durable. This is because it replaces the heavier glass substrates of a LED with lighter, stronger plastic substrates. OLED films are quite durable and can withstand demanding environments that require wider operating temperatures without failing.

From a current viewpoint, keeping in mind the innovative OLED application modules that are surfacing on a daily basis, things look increasingly promising for the OLED market in future years.