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Tripping The Light Fantastic

Forget dials and pointers, LCD screens, and incandescent illumination. If OLED technology can live up to its promise, automotive interiors will be very different places.

Within 20 years or less, your PDA will be a pen that has a full-color roll-out screen that does everything today’s PDA screen does, but weighs very little and takes up next to no room. Similarly, your paper or magazine will be downloaded to a lightweight flexible “book” that allows you to scroll through stories and save items of interest to an on-board chip. Laptop computers will follow the same path, ditching LCD screens for thinner (< 2 mm) screens that will unroll from the base. Your 80-in diagonal television will come in a tube and cover a large wall, while ultra-thin lighting fixtures that use very little energy replace fluorescent and incandescent illumination. What does this have to do with the future of cars and trucks? Everything. For the same OLED (Organic Light Emitting Diode) technology found in these examples will make its way into vehicle interiors.

Despite stating that OLED technology is growing by 100% per year in small electronics and that technological barriers are falling, Dr. Alfred Felder, head of OSRAM Opto Semiconductors’ OLED Business Unit (San Jose, CA; www.osram-os.com), cautions patience: “Materials, processes, and capabilities are getting better all of the time, and we are coming close to automotive specifications with at least a couple of the colors necessary for a full-color display. However, there are some technical hurdles that must be overcome before we can move from an inflexible [glass-encased] to a flexible display that can meet OEM specs.” The hurdles include creating new UV-resistant plastics impermeable to moisture and air infiltration; materials that meets a 10-year life requirement under the harshest conditions (-40°C to 90°C, 1,500 hours at 85°C and 85% humidity, no more than a 5% loss of light output over its lifetime). Also, though the current cyan-blue used in prototype full-color displays is getting closer to the 10,000-hour automotive lifecycle requirements, Dr. Felder says, “It’s quite good, but not the most effective color for automotive applications.”

However, blue OLEDs used to have a lifespan of just three minutes before luminosity fell 20%. Now it is over 1,500 hours, and they consistently go 35,000 hours before the number drops to 50% of its original value. The goal is 100,000 hours, which would put it on par with LCD technology, and recently some researchers claim they have seen 70,000 hours of operation before luminosity dropped by half. Both red and green OLEDs are at or beyond the 200,000 hour barrier, which means failing blue OLEDs would cause the color of the display to shift over extended periods. However, automotive OLEDs will have to run for just 10,000 hours with less than 5% degradation to be considered ready for production.

“OLED displays,” says Mike Gauthier, director of Corporate Technology, North America, Siemens VDO (Auburn Hills, MI; usa.siemensvdo.com), “have already made their way to MP3 players, cell phones, digital cameras, and aftermarket car radios. In-car entertainment systems will be next, and from there the technology will move to navigation screens, the instrument panel center stack displays, and finally to the instrument cluster.” At first, these screens would be glass encased, eventually migrating to flexible displays as the technology reaches maturity. While Gauthier says the glass-encased displays still would liberate space in the instrument panel–thereby making more room for HVAC ducting, crash structures, and control units for vehicle systems–he sees a day when flexible screens take center stage. “Your PDA would double as the navigation system, and plug into a socket on the console. Later, the technology should allow a clear flexible screen to be laminated into the windshield and used as a giant heads-up display.” The latter might even use “augmented reality” to display virtual road signs, the speed of traffic ahead, and paint lines on the road for the driver to follow to his destination.

Both Gauthier and Felder agree OLEDs–which are manufactured using many of the same techniques used to make semiconductors–will follow a version of Moore’s law that will see them get smaller and more capable as the price per unit of output diminishes. Today, the size of the conductive grid–the space between the X and Y electrical conductors–is measured in nanometers, with this gap expected to drop further. “We still have to fight with the yield of the displays, the cost of manufacturing, coming up with better materials, and how long they can last,” says Felder, “but the best indicator of where this technology is going comes from looking at who is investing in it today.” This group includes the U.S. Dept. of Defense and Dept. of Energy; Los Alamos and other national labs; major universities; companies like Siemens VDO, OSRAM, and Universal Display Corp.; as well as the largest manufacturers of LCD technology today. “There is a multi-billion dollar LCD infrastructure that isn’t going to lie down and die without a fight,” says Felder, “but makers of that display technology are some of the heaviest investors in OLED technology.”

One reason is that, as Gauthier puts it, “This is a disruptive technology, a real game changer that will overtake the display industry once it reaches its tipping point.” Another is that the basic technology also can be used for illumination, making it possible for OEMs to source their OLED products from a wider variety of suppliers at a lower price. And while current OLED lighting technology is between ¼ and ½ as efficient as state-of-the-art lighting technologies, there not only exists the potential to replace fluorescent lighting in buildings–OLEDs consume about 1/10 the energy to produce the same amount of light–but to weave flexible OLED screens into the headliner, backlight, and elsewhere within the vehicle. “You could easily replace existing lighting with this technology,” says Gauthier, “and change the way you use light by weaving strips of this material into different areas of the interior.” According to Felder, OLED lighting is moving forward rapidly: “Last year we could produce only seven lumens per Watt. Now we are close to 20.” Still, as it was with so many earlier technologies, it will take an application, or series of applications, that allow the technology to reach the point where profits exceed costs, and consumer demand grows at a high rate. And though Dr. Felder cautions restraint, Gauthier claims his research shows that technology is moving forward at a much faster rate than ever before: “I doubt it will take 20 years before we see full-color OLED technology on the market in a wide and growing variety of applications.”