Jin, Hongzheng - Organic light-emitting diodes (OLED)

Organic light-emitting diodes (OLEDs) are made up of thin films of organic materials that give off light of various colors when voltage is applied to them. The basic structure of an OLED is shown in the diagram. It generally contains a glass substrate, a transparent anode (most often indium-tin oxide, or ITO), active organic layers and a low-work function metal cathode layer on the top. When a small external voltage is applied between the cathode and anode, charges (electrons and holes) are injected into the organic materials. At some point, the charge carriers will recombine and release energy in the form of photons, i.e., lights.

OLED technology, enables full-color, full-motion flat-panel displays with a level of brightness and sharpness not possible with other technologies.

OLED displays are thinner and weigh less because they are self-luminous and do not require backlighting. OLED displays also have a wide viewing angle up to 160 degrees even in bright light, and they use only two to ten volts to operate which provides for maximum efficiency.

OLED displays are to be used in portable devices such as cellular phones, digital cameras, camcorders, DVD players, PDAs, laptops, car stereos, televisions and so on. It's a multi-billion value market!

See the following examples for some of the products where OLED displays have been utilized.

Kodak EasyShare LS633 Digital Camera, available in Europe market. The first digital camera to use an active-matrix OLED displays
Pioneer Car stereo with full-color OLED display
JVC KD-AR7000 car stereo with full-color OLED display
Fujitsu Mobile Phone, F505i GPS, with Pioneer 4096 colors, 1.1", 96RGB ´ 72 OLED front display. Red phosphorescent emitting material developed by Universal Display Corp. is used in this display.
Samsung E700 Mobile Phone, available in market Front Display: OLED display, 256 colors, 64 ´ 96 pixels
Samsung E715 Mobile Phone, available in market Front Display: OLED display, monochrome, 80 ´ 64 pixels
Samsung Wrist watch GPRS wireless phone OLED screen, 256 colors,96 ´ 64 pixels
Philips Philips' OLED display technology is used in the Sensotec men's shaver introduced by Philips-Norelco in July 2002.
Philips Philips' 13" PolyLED TV prototype. Video on this PolyLED TV from Philips Video on polymer organic light-emitting diodes from Philips
Delta OptoElectronics MP3 Player, Single color (green) OLED display
International Display Technology (IDTech) 20" OLED display prototype, WXGA 1280RGB´768 pixels
eMagin OLED SVGA microdisplay prototype
Seiko-Epson World's largest 40" OLED display (prototype), Widescreen XGA 1280RGB´768 pixels
Sony Full-color OLED display in mass production, to be used in Sony's CLIE 'PEG-VZ90' personal entertainment handheld. Size: 3.8", Piexels: HVGA, 480´RGB´320, 262,144 colors, Color gamut (NTSC ratio): ~100%, Brightness: 150 cd/m², Response time: ~10 micro sec., Contrast: ~1000:1.