Attributes such as small size, low power consumption and rapid switch-on time have lead to a widespread adoption of high-brightness LEDs in vehicles. Since the first use of red LEDs in center high-mounted stoplights (CHMSLs), LEDs have become a common sight on all types of vehicles, including automobiles, buses, trucks, motorcycles and even trains and aircraft.

According to Strategies Unlimited, around 15% of all high-brightness LEDs manufactured in 2003 were deployed in vehicles, representing a market value of around $400 million.

Exterior signal lights

BMW 3 series On automobile exteriors, LEDs are used in CHMSLs and brake lights, as well as turn indicators and tail lights. Similarly, marker lights, stop lights, turn lights and tail lights on trucks and buses have all been implemented using LEDs.

Around 56 million light vehicles were produced in 2003, of which around 37% had LED-based CHMSLs. European car makers are the furthest advanced in adopting this technology, while the US continues to see modest growth. In contrast, the Japanese market is at the start of a major ramp for exterior LED signaling functions. However, only around 3% of new vehicles had LED-based stop, turn or tail lights.

Forward lighting with LEDs

Ford Model U LED-based forward lighting is in its infancy, although many car manufacturers have experimented with the use of white LED headlights in their concept vehicles. However, production models with LED headlights are not expected to hit the market until 2006-2007.

Before then, LEDs will be used in daytime running lights (DRLs) or in fog lights. In January 2004, Audi announced that its new A8 would be the first production vehicle to feature DRLs based on white LEDs.

Interior Lighting

While the HB-LED market for exterior automotive lighting applications was worth some $110 million in 2003, the market for interior applications was more than double that figure, according to Strategies Unlimited. LEDs are now used as backlights in the instrument panels in around 80% of European cars, with manufacturers having adopted specific colors. In the US, the use of LEDs is still limited to a few high-end models, while Japan is witnessing rapid growth.

Toyota CorollaLEDs are also used extensively in cars for courtesy lighting functions such as map lights or to illuminate switches. Other miscellaneous applications in vehicles include head-up displays (in the new BMW 5 series) and air purification using UV LEDs (Toyota).

Reasons for using LEDs

OEMs are attracted by the potential to reduce energy consumption, and the space savings that can be realized using smaller LED fixtures. Both OEMs and consumers benefit from the styling potential of LEDs, which enable more attractive and distinctive designs, as well as the robustness and long lifetime of the solid-state light sources, which cuts down on maintenance. Consumers also benefit from safety factors, for example due to the faster turn-on of brake lights which reduces the risk of rear-end collisions.

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