01-03-2013, 02:36 PM
ELECTRONIC PAPER: Organic Light Emitting Diodes
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It’s All In The Way We See Things:
If ever a technology has begged to be disrupted, it is Liquid Crystal Displays. Invented in 1963 and envisioned as a slimmed-down replacement for bulky cathode ray tubes or as screens for wall mounted televisions – a use never realized due to problems scaling up to large surfaces – liquid crystal displays have instead become the standard for everything from watches to laptop computers. Despite this, however, remains high production and commercial expenses that have never come down enough to successfully mass market these displays, leaving the technology vulnerable to new innovations
With the imaging appliance revolution underway, the need for more advanced handheld devices that will combine the attributes of a computer, PDA, and cell phone is increasing and the flat-panel mobile display industry is searching for a display technology that will revolutionize the industry. The need for new lightweight, low-power, wide viewing angled, handheld portable communication devices have pushed the display industry to revisit the current flat-panel digital display technology used for mobile applications. Struggling to meet the needs of demanding applications such as e-books, smart networked household appliances, identity management cards, and display-centric handheld mobile imaging devices, the flat panel industry is now looking at new displays known as Organic Light Emitting Diodes (OLED).
What Is Organic Light Emitting Diodes (OLED)?
Organic Light Emitting Diode technology, pioneered and patented by Kodak/Sanyo, enables full color, full-motion flat panel displays with a level of brightness and sharpness not possible with other technologies.
Unlike traditional LCD’s, OLED’s are self-luminous and do not require backlighting, diffusers, polarizers, or any of the other baggage that goes with liquid crystal displays. Essentially, the OLED consists of two charged electrodes sandwiched on top of some organic light emitting material. This eliminates the need for bulky and environmentally undesirable mercury lamps and yields a thinner, more versatile and more compact display. Their low power consumption provides for maximum efficiency and helps minimize heat and electric interference in electronic devices. Armed with this combination of features, OLED displays communicate more information in a more engaging way while adding less weight and taking up less space.
Active Displays:
In contrast to the passive-matrix OLED display, active-matrix OLED has an integrated electronic back plane as its substrate and lends itself to high-resolution, high-information content applications including videos and graphics. This form of display is made possible by the development of polysilicon technology, which, because of its high carrier mobility, provides thin-film-transistors (TFT) with high current carrying capability and high switching speed.
In an active-matrix OLED display, each individual pixel can be addressed independently via the associated TFT’s and capacitors in the electronic back plane. That is, each pixel element can be selected to stay “on” during the entire frame time, or duration of the video. Since OLED is an emissive device, the display aperture factor is not critical, unlike LCD displays where light must pass through aperture.
Therefore, there are no intrinsic limitations to the pixel count, resolution, or size of an active-matrix OLED display, leaving the possibilities for commercial use open to our imaginations. Also, because of the TFT’s in the active-matrix design, a defective pixel produces only a dark effect, which is considered to be much less objectionable than a bright point defect, like found in LCD’s.
Summary:
The Organic Light Emitting Diode forms of display still have many obstacles to overcome before it’s popularity and even more importantly, its reliability are up to par with standards expected by consumers. Although the technology presents itself as a major player in the field of displays, overcoming these obstacles will prove to be a difficult task. However, the OLED’s advantages over LCD’s and future outlook have many in the industry goggle-eyed at the realm of possibilities. For all we know and can hope for…OLED’s could change the ways in which we see things.