After doing a booming business in sales to the information technology (IT) and home-appliance markets in 2007, Taiwanese suppliers of LED (light-emitting diode) lighting are anticipating a surge in automotive applications for their products in 2008, according to Allen Cheng, a researcher at Taiwan`s Automotive Research & Testing Center (ARTC).



Cheng made the statement at a recent industrial seminar held by the ARTC. The seminar looked at global automotive market development trends, future opportunities for the local automotive industry, and the automotive applications of LED lighting.



In 2007, LED lighting became more widely used in notebook PC and LCD TV backlight units (BLUs). Some leading market-research firms forecast that LED lighting will capture a 10% share of this market in 2008.

Automakers are also embracing LED light sources for use in direction signal lights, tail lights, dashboard illumination, and other interior illumination applications, Cheng said. LED headlamps are expected to become more common in 2008, especially on luxury car models, he said.

Emitting Higher Power

The global production value of LEDs is estimated to have reached US$6.48 billion in 2007. Cheng estimates that the figure is set to grow at a compound annual growth rate (CAGR) of 13.8% up to 2010.

Cellphone applications (such as handset backlight modules and keypads) generate the bulk of the LED revenue, but growth potential in this area is considered limited. Cheng said that in future, growth in the LED lighting market will be driven by LCD backlight module, automotive illumination (including headlamps), and general indoor/outdoor illumination applications.

Quoting statistics compiled by Strategic Unlimited and sorted by ARTC, Cheng said that the CAGRs during the period of 2007 to 2010 of the LED revenue in different markets including handsets, LCD backlight modules, automotive, general lighting (indoor/outdoor), and others would be -0.4%, 25.8%, 19.7%, 17.6%, and 9.5%, respectively.

The automotive LED revenue is expected to account for 17.6% of the overall LED market in 2007, the researcher said, and the ratio would jump to 22.7% in 2010.

More and more devices and systems on new model cars are adopting LEDs, including tire pressure detectors, sidelights, footrest lights, mirror-side turn signals, tail lamps, third brake lights, daylights (auxiliary lamps in front of a vehicle to alert pedestrians), interior lights (reading lights, dashboard illumination, and UV light catalysts), insignia decoration lights, license-plate lights, IR night-vision, and headlamps-one of the most important application segments.

LED use is rapidly growing in automobiles, according to data compiled by ARTC from the research results of Deutsche Bank, Daewoo Securities, and KGI Securities. The report forecast that about 40% of car interior lights, about 30% of tail lights, about 10% of headlights will use LED lamps by 2010.

Advantages

The rising popularity of LED lamps owes to the several advantages of the technology, Cheng said. These include:

Environment friendliness: LED lamps use over 50% less power than traditional bulbs. According to reports by the Energy Information Administration of the United States, the U.S. could reduce fuel consumption by 1.4 billion gallons a year if all automobiles in the nation used LED lighting sources.

Safety: The response time of the LED is shorter than 0.1 second, meaning that if a vehicle has LED tail lights and is driving at 100 kilometer per hour, the driver of the vehicle behind can respond earlier at a distance of just seven meters.

Durability: Under ideal operating temperatures, LED lamps are expected to have a lifespan of over 100,000 hours, about 40 times that of high-intensity discharge (HID) lamps and a 200-fold improvement over halogen bulbs.

Design flexibility: LED lamp modules can be shaped to form various beam shapes and are easier to adapt to the vehicle design compared to conventional light bulb lamp sets.

Other: LED lamps have superior shock-resistance and emit light with better color rendering than traditional bulbs.

Challenges

Cheng stressed, however, that several hurdles need to be surmounted to broadly expand LED lamp usage in automobiles, especially for headlamps. These challenges include increasing brightness, expanding the illumination scope, and solving the heat-dissipation problems of LED lamps.

According to Cheng, most of the LEDs available in the market have a light-emitting efficiency of 45 to 70 lm/w, though some firms have claimed successful development of products with 70-100 lm/w. The brightness is insufficient for headlamp use. Some mass-produced luxury car models, such as the Lexus LS600, are equipped with LED headlamps with low-beam LED modules, but still rely on a high-beam assisted projector module with traditional lighting sources.

Due to LED`s relatively narrow illumination area, Cheng said, currently all LED headlamp solutions are structured with matrix LED modules, which are more difficult to shape into ideal light configurations. In addition, the optical designs of LED headlamps are more complicated.

The third bottleneck in developing the LED headlamp market, and the one many consider the most challenging, is the heat-dissipation problem.

According to Cheng, LED lamps convert only 15% of the power input into, meaning that 85% of the power is dissipated as heat. LED temperatures can climb to 140-degree centigrade. At that temperature the lamps` light-emitting efficiency falls to 70% and the maximum operating temperature of such lighting sources is only 185-degree. In addition, the resin materials for LED packaging decay easily in high temperature environments.

In a general automobile engine compartment, Cheng said, the environmental temperature is about 80 to 90 degrees centigrade, leaving little room for a super hot LED headlamp. Some heat-dissipation methods have been applied to LED bulbs, but none are ideal or cost-effective. These methods include material heat-dissipation (using resin material as a heat duct); natural heat-dissipation (attached with some auxiliary devices such as aluminum heat sinks and pipes for heat convection-a popular approach in IT and electronics products, but not efficient enough for some automotive applications); and compulsory methods (use of liquid cooling devices alone or in conjunction with cooling fans, requiring more space and higher cost).

With an eye on the lucrative automotive headlamp market, Cheng said, a group of global tier-one parts brands and some lighting-source companies have been actively trying to develop solutions to overcome technical bottlenecks that are affordable enough to attract global automakers. These firms include Stanley (with five LED modules for high-beam and two for low-beam), Koito (six high-beam, five low-beam and is incorporated in a adaptive front-lighting system, or AFS), Osram (four-in-one module with efficiency of 300 lm/module, equipped with large-sized heat-dissipation), Toyota Gosei (12 modules), and Hella (seven modules, in honeycomb design).

Projects

With headlamp sets supplied by Koito with LEDs from Nichia, Cheng said, the LS 600 luxury sedan is a recent example of successful LED headlamp application. Each of the new car model`s headlights adopts five 400 lm LED modules for low-beam while the high-beam is still powered by halogen bulbs. The LS600`s LED headlight sets adopt several heat-dissipation solutions to counter the high temperature in the engine compartment, including cooling fans, pure-water circulating cooling pipes, structural changes in LED chip designs, and adoption of glass packaging materials for LEDs. Another example is Audi`s R8 sport car, the LED headlight was developed by Magneti Marelli with LED modules supplied by Philips Lumileds.



Some other automakers are going to adopt LED headlamps on their new models, including Audi`s A8 luxury sedan (in cooperation with Hella), VW (Hella), and GM (Visteon).

Taiwan`s Chance

In Taiwan, according to Cheng, the ARTC has been leading the development of automotive LED headlamp applications. The center also has helped set up some strategic alliances on the island for future business development.

The ARTC began designing and developing automotive LED headlights in 2003, when Koito, Valeo, and Hella announced their LED headlight prototypes at the Tokyo Motor Show. The center applied its strong R&D and test capabilities to LED headlight optical design and simulation tests, as well as product design, testing, and certification procedures.

After Stanley demonstrated its new-generation prototype of automotive LED headlight in 2004, the ARTC successfully mapped out its first-generation prototype of such product.

In 2005, the center continued to push its second- and third-generation prototypes and completed installation work on vehicles. Around the same period, Hella of Germany, one of the world`s leading automotive lighting manufacturers, showcased its conductive-type LED headlamp prototypes at some auto and parts shows.

Between 2006 and 2007, the ARTC developed its fourth-generation LED headlamp prototype and more actively involved in heat-dissipation solutions for such products, while upgrading the local industry`s technical capability to a world-class level ready for mass production in the near future. In 2007, both the LS 600 and Audi R8 featured LED headlamps.

As the key promoter of local automotive LED headlamp development, the ARTC has helped local makers set up two strategic alliances, including the ALS, over the past two years.



More recently it assisted the formation of the Aftermarket LED Automotive Headlamp R&D Alliance. The alliance aims to introduce at least two new LED headlamps for European passenger cars and one for big-bore (over 750cc) motorcycles within 18 months.

The new Aftermarket LED Automotive Headlamp R&D Alliance has four member companies: Depo Auto Parts Ind. Co. (one of Taiwan`s top-two auto-lamp makers), Everlight Electronics Co. (a major LED packager that has been moving aggressively into automotive applications) AMA Precision Inc. (a leading supplier of cooling solutions), and Epistar Corp. (a big manufacturer of high-brightness LEDs employing its self-developed metal organic vapor phase epitaxy, or MOVPE, technology).

An earlier cooperative arrangement, the Advanced Auto-lamp System R&D Alliance (ALS), was formed in 2004 under the organization of ARTC to upgrade the global competitiveness of Taiwan`s auto lamps by focusing on the original-equipment (OE) sector. In 2006, the alliance helped its members commercialize AFS products, which are now used on some locally assembled car models.

ALS was initiated by ARTC and has 10 other members: Ta Yih Industry, TYC Brothers Industrial, and Depo, Taiwan`s top-three auto-lamp makers; Stark Technology, which is involved in IT solutions and systems integration, and Sine Technology, which works on auto electronics and navigation system integration, both owned by automaker Yulon Motor; and the Electronics Research & Service Organization (ERSO) of the Industrial Technology Research Institute (ITRI), Plastic Technology Development Center, National Central University, Da Yeh University, and National Taipei University of Technology.

`The automotive LED application market is expected to take off at a very high speed soon," Cheng said, "Taiwan is expected to seize more opportunities in the new market with the collective efforts of local research institutions and private makers."

(by Quincy Liang)