Winning Technologies: Organic Light Emitting Diode

Dec. 21, 2004
A new display technology from Eastman Kodak Co. rewrites performance and cost attributes of flat panels.

The time: an early evening in the late 1980s. The place: an R&D lab at Eastman Kodak Co., Rochester. A researcher retrieving car keys in an unlit room unexpectedly sees a glass substrate glowing. By forgetting to power down an experiment, a Kodak technician inadvertently has created a watershed moment in flat-panel display technology. "Organic light-emitting materials were being studied in that lab, both in terms of photon emission and in the translation of photons to electrons -- as in a solar cell," explains James C. Stoffel, chief technical officer, director of R&D, and senior vice president at Kodak. He says the glowing substrate and the curiosity it generated led to the company's announcement earlier this year of a new display business unit. He describes the evolution as "one of the shining examples [no pun intended] of what studies in fundamental science can still yield." In retrospect, Kodak's dedication to basic research is admirable because in the 1980s it was not obvious that the payoff of that one experiment, some 50 patents later, would show the potential of displacing conventional color flat-panel displays. Kodak's organic light emitting diode (OLED) technology competes by being brighter, thinner, lighter, and cheaper, with very low power requirements, notes research analyst David E. Mentley, vice president, Stanford Resources Inc., San Jose. He calls the results "spectacular." Unlike other flat-panel displays, OLEDs have a wide viewing angle (up to 160 degrees), even in bright light. Kodak says the low power consumption (only 2 to 10 volts) helps minimize heat and electrical interference in electronic devices. With comparable images Kodak claims a 50% energy savings for a 2-in. OLED over a backlit liquid crystal display (LCD). Eliminating backlighting also provides an environmental advantage. The backlighting on conventional LCDs can involve fluorescent lamps containing mercury -- a material with potential regulatory and disposal concerns. Kodak observes that European legislation already requires the special separation, packaging, handling, and disposal of such substances. The reduced use of raw materials also is an environmental plus. OLEDs use one less glass plate than conventional LCDs -- reducing the entire mass of the display by over 50%. To gain those benefits, Kodak's OLED technology uses multiple layers of organic film that is thinner than a wavelength of light. The basic OLED cell structure consists of a stack of thin organic layers sandwiched between a transparent anode and a metallic cathode. The organic layers comprise a hole-injection layer, a hole-transport layer, an emissive layer, and an electron-transport layer. When an appropriate voltage (typically a few volts) is applied to the cell, the injected positive and negative charges recombine in the emissive layer to produce light (electroluminescence). Kodak's research led to patents on basic OLED materials, device structures, doping techniques to improve efficiency and control color, thin-film deposition, and pattern methods, as well as design and fabrication procedures for both passive and active-matrix OLED panels. "In time, displays based on Kodak technology could be installed in just about any consumer electronics device from cell phones to computer monitors," says Stoffel. "Early on the major applications will be in the small portable device area where people really want high-quality visual content -- movies or DVD or Internet downloading of pictures," adds David J. Williams, general manager, OLED display technology. The low power consumption is the other consideration drawing OLEDs to small, portable electronic devices, says Williams. Battery run time is substantially increased, solving a common complaint among users of digital cameras that have LCDs as viewfinders. Is there a theoretical limit to the size of OLED displays? "None that seem to be defined by materials or the known fundamentals," says Stoffel. (Kodak has patents covering the coating of continuous sheets of plastic.) OLEDs do not even seem to be limited to the display market. Stoffel cites recent university research that suggests that as a lighting source OLEDs would be far more efficient than fluorescent lights. Kodak is moving very quickly to exploit its research edge with color active-matrix OLED displays. While the competing LCD technology took decades to evolve, Kodak progressed from showing a 2 1/4-in. color active matrix OLED in October of 1999 to a 5 1/2-in. version six months later, and Stoffel anticipates a 10-in. size next year. To accelerate commercialization, Kodak is forming strategic alliances. For example, in April Kodak partnered with Sanyo Electric Co. Ltd. and ULVAC Japan Ltd. to jointly develop manufacturing equipment. Kodak also is teaming with Sanyo to develop next-generation color active-matrix displays. Other licensing arrangements have been made with eMagin Corp., Ritek Corp., Nippon Seiki Co. Ltd., and TDK Corp. The company also supplies patented materials to its licensees. Although volume production of active-matrix OLEDs is still in the planning stage, that has not limited the enthusiasm of market analysts or Kodak. Stanford Resources' Mentley estimates that the OLED display market will grow from $3 million in 1999 to $714 million by 2005. But Boston's Display Search says the 2005 market will exceed $3 billion. In a keynote speech at Photokina, a photographic-industry trade show in Germany, Kodak President and CEO Daniel A. Carp predicted that "the market for OLED displays could reach $4 billion within five years." The actual size of the projected market is obviously not the challenge, observes Mentley. "Kodak's formidable task is to select the right business model to exploit the OLED opportunity and to assure that buyers of electronic devices will have ready access to OLED-equipped products." In assigning internal responsibility for OLEDs, Carp seems to belong to the same school of thought as Harvard Business School management guru Clayton M. Christensen. On October 23 Kodak announced the formation of a new business unit for flat panels. In Christensen's 1997 best-selling book, The Innovator's Dilemma: When New Technologies Cause Great Firms to Fail (1997, Harvard Business School Press), he says that new opportunities need to be exploited by new management. At Kodak that management will be headed by Les G. Polgar, president and general manager, and his newly created business unit will be located not in Rochester, but in Walnut Creek, Calif. Polgar says OLEDs are "the technology that brings images to life. Displays are the window to the world for use of electronic devices. The advances in telecommunications and microprocessor speeds can only find their fullest expression if that window can accommodate them. "The Kodak moment of this century," he observes, "will occur when people turn on their screens."

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