OLED Tutorial

Organic Light-Emitting Diode (OLED) Technology

An OLED is an electronic device made by placing a series of organic thin films between two conductors. When electrical current is applied, a bright light is emitted. This process is called electrophosphorescence. Even with the layered system, these systems are very thin, usually less than 500 nm (0.5 thousandths of a millimeter).

When used to produce displays, OLED technology produces self-luminous displays that do not require backlighting. These properties result in thin, very compact displays. The displays also have a wide viewing angle, up to 160 degrees and require very little power, only 2-10 volts.

OLED displays have other advantages over LCDs as well:

• Increased brightness
• Faster response time for full motion video
• Lighter weight
• Greater durability
• Broader operating temperature ranges

Comparing Technologies

Liquid Crystal Displays (LCDs)

For comparison, LCDs, which are widely used today, are nonorganic, nonemissive light devices, which means they do not produce any form of light. Instead they block/pass light reflected from an external light source or provided by a back lighting system. The back lighting system accounts for about half of the power requirements for LCDs, which is the reason for their increased power consumption (over OLED technologies).

LCD production involves the same sort of layering technique used in OLED displays, with some modification. First there is the formation of electrodes on two glass substrates. Then the substrates are joined together and the liquid crystals are sealed within them. Backlights are used to spread light out by a thin light diffuser. Finally the system is placed into a metal frame.

Cathode Ray Tubes (CRTs)

Displays made from CRTs are produced using electron tubes in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected toward a phosphorescent screen that forms one face of the tube. The electrons beam leaves a bright spot wherever it strikes the phosphor screen.

Pros and Cons

CRTs

• Cost less and produce a display capable of more colors than LCD displays
• CRTs also use emissive technology, meaning that they can provide their own light – this means you can view images from any angle

LCDs

• LCDs have gained popularity due to their smaller, lighter form factor and their lower power consumption
• Many users report lower eyestrain and fatigue due to the fact that LCD displays have no flicker
• LCDs emit fewer low-frequency electromagnetic emissions than CRTs

Additional sources of information*

Oled-Info.com
Oled-display.net
How Stuff Works – LCDs

Companies Developing OLED Displays
Cambridge Display Technology
Universal Display Corporation
Dupont Displays – Olight