Down the Line: Organic LEDs Light the Way to the Future
Organic light-emitting diode (OLED) technology enables full-color, full-motion flat-panel displays with a level of brightness and sharpness not possible with other technologies. Unlike traditional liquid-crystal displays (LCDs), OLEDs are self-luminous and do not require backlighting. This eliminates the need for bulky mercury lamps and enables a thinner, more compact display.
Unlike other flat panel displays, OLEDs have a wide viewing angle-up to 160 degrees, even in bright light. Their low power consumption-only 2 to 10 volts-provides for maximum efficiency, and helps minimize heat and electric interference in electronic devices, such as cell phones and digital cameras.
According to Hrishikesh Bidwe, a research analyst at Frost & Sullivan Inc. (San Antonio), OLED technology holds huge potential, but it still needs to be perfected. "To establish a clear lead over competing technologies, such as LCDs, manufacturers have to ensure that the superior brightness, luminance and color performance of OLED devices do not deteriorate with age or use," says Bidwe. "Concerted efforts are underway to find a low-cost solution to reduce the impact of hostile environments such as heat, moisture and dust, while preserving the advantages of low weight and thin profile.
"Initiatives to enhance device stability are important because improved blue, green and red emitters with longer lifetimes are necessary to scale up efficiency," adds Bidwe. "Considerable research is being conducted on developing an easily manufacturable structure that forwards more light emitted from organic molecules without increasing the reflection of ambient light. Several companies are also collaborating to develop innovative OLEDs to meet consumer demand."
Bidwe says the hectic pace of technology development in the OLED market has led to prominent manufacturers ramping up production to introduce greater volumes of OLED-based products commercially.
"Currently, small molecule OLEDs (SMOLEDs) are proving to be the biggest challenger to LCD, especially in the small-sized displays market," notes Bidwe. "Constraints in current manufacturing techniques make SMOLEDs unsuitable for large displays, leading them to target the subdisplay segment in mobile phones."
According to Bidwe, SMOLEDs are used in 90 percent of flip phones with subdisplays. He says the technology has a variety of benefits, such as wide viewing angles, full color capability and much higher contrast ratios over LCDs. "With such superior features and increasing research on newer manufacturing techniques, OLEDs are all set to extend their domination from small-sized displays to all display segments very soon," claims Bidwe.
Today's flat-panel displays typically use heavy, inflexible glass that can break during transportation and installation. But, in the future, laptop computers, televisions and other devices may simply be rolled up when not in use.
Engineers at the University of Toronto have developed flexible organic light-emitting device (FOLED) technology that could lay the groundwork for future generations of bendable television, computer and cell phone screens. The lightweight, flexible materials range from transparent plastic films to reflective metal foils that can be bent or rolled into any shape.
"It opens up a whole new range of possibilities for the future," says Zheng-Hong Lu, a professor in the department of materials science and engineering. "Imagine a room with electronic wallpaper programmed to display a series of Van Gogh paintings, or a reusable electronic newspaper that could download and display the day's news and be rolled up after use." Lu claims that FOLED technology lends itself to low-cost mass production.
Researchers at Royal Philips Electronics (Amsterdam) have already developed prototypes of rollable displays that combine active-matrix polymer electronics with a reflective "electronic ink" front plane on an extremely thin sheet of plastic. The lightweight, large-area displays can be rolled up into a small-sized housing when not in use.
Philips hopes to mass-produce flexible displays that can be integrated into everyday objects such as pens. "The availability of such displays would greatly stimulate the advance of electronic books, newspapers and magazines, and also new services offered by mobile phone network operators," says Jim Veninger, general manager of emerging display technology. "These applications currently depend on fragile, heavy and bulky laptops or small, low-resolution mobile phone displays, which both have clear drawbacks."