When it comes to pickup trucks, the future’s getting brighter. Ford has announced that its all-new F-150, which launches in the market later this year, will be the first pickup truck to offer LED headlights.
The new LED – short for “Light-Emitting Diodes” – lights are expected to be more durable and last some five times longer than other headlights, while using some 60 percent less energy than halogen bulbs.
“It is creating light through electronic means,” says Mahendra Dassanayake, senior technical leader for opto-electronics at Ford’s research centre in Dearborn, Michigan. “An LED light has a semiconductor chip that produces blue light. That blue light interacts with phosphor and produces white light.”
At one time, all cars used incandescent headlights, which contain a filament that’s heated up to produce light. Their main drawback is that they produce more heat than light, which results in less light, more energy use, and a shorter lifespan than in newer types of bulbs.
Halogen bulbs also contain a tungsten filament, but it’s inside a capsule containing halogen gas. They get very hot – about 600˚ Celsius in the capsule, Dassanayake says – but they produce brighter, whiter light and last longer than incandescent bulbs.
Some cars use HID (high intensity discharge) headlights, which use an electrical arc between tungsten electrodes to create light. They’re often called xenon headlamps, but while some HID bulbs use other types of vapour to create light, all of them start off on xenon gas to produce some light right away. That’s because it takes a while for these bulbs to warn up to their full intensity, which is why they don’t seem as bright when they’re first turned on. Like halogen lights, they also get very hot, but they have a longer lifespan. Their energy consumption is also low compared to the amount of light they produce, but they’re expensive.
LED bulbs are also pricey, but Dassanayake says they can last up to five times longer than current types of headlights. They’re also ideally suited to trucks because of their robust construction. The extreme vibration from off-road bumps and jostles can be hard on a filament, but the LED bulb doesn’t contain one. Unlike HID headlights, they reach their full brightness almost instantly. They’re also very small, which allows for more freedom when designing and engineering the lamp design.
The Ford lamp includes a unique lens, designed specifically for the F-150, that’s carved with 16 optical surfaces and 80 facets to magnify the light and distribute it evenly.
The semiconductor chips in the LED assembly get hot—about 50˚ Celsius—and so the assembly includes a heat sink to help channel the heat away for longer lifespan. But the bulb itself stays cool, so much so that Ford is working on special coatings and surface treatments to reduce the likelihood of snow buildup. Other types of bulbs melt snow as it accumulates when driving, but the LED bulbs don’t get hot enough.
Dassanayake says that the LED lamps are 50 to 60 percent more efficient than halogen lights, and about 30 percent more than HID lamps. “It will improve as time goes on,” he says. “This is technology at its basic inception. I think LED is going to be the future of lighting.”
Mahendra Dassanayake, Ford’s senior technical leader for opto-electronics, in his light lab
Of course, LEDs are already used in numerous automotive applications, including brake lights, daytime running lights, and in vehicle interiors. Dassanayake presides over a laboratory that can simulate daylight in almost every part of the globe, and at any time of the day. It allows him to design exterior and interior lighting on vehicles for various markets, knowing how they’ll look and how visible the lights will be. “Managing light is a huge innovation here,” Dassanayake says. “It’s a team effort. We have a whole bunch of engineers that work at Ford, and we bring in one of the suppliers. We create the idea and the feasibility, and they execute it.”