Rise of Adaptive Driving Beam

　　With the whole tech world marching to its own particular robocar promotions, it seems trivial to pose the issue of vehicle headlights designed for human drivers to see better.

　　After all, the utopia of autonomous vehicles is a future in which everybody will be safe without having to see anything beyond his or her nose.

　　However, nowadays, almost half of all traffic fatalities occur at night. While we await the birth of George Jetson, it might not be a bad idea to improve road visibility in the dark — today.

　　Car OEMs, Tier Ones and light source technology suppliers in Europe and Japan are already piling into the emerging market of Adaptive Driving Beam (ADB).

　　In a recent interview with EE Times, Lumileds, a lighting company headquartered in the Netherlands, explained that when onboard cameras sense oncoming vehicles or pedestrians, ADB can adjust the lights automatically, either dimming individual LEDs in the lamp or shifting the beam downward and sideways.

　　“You can leave your lights always on high beam to provide maximum lighting,” while ADB adjusts the beam away from oncoming drivers, said Dirk Vanderhaeghen, senior director of global strategic marketing for automotive LEDs at Lumileds. “We are talking about lighting designed for safety."

　　In Europe, Vanderhaeghen said, participants in the ADB fray aren’t just high-end vehicle suppliers like Audi and Mercedes-Benz. ADB is coming to compact cars from Opel, Peugeot and Citroen. Japan’s Toyota is also big on ADB. “Even in China, we are now seeing RFQs for ADB,” he added.

　　In an interview with EE Times, Hector Fratty, CEO of Driving Vision News and a Paris-based expert in automotive lighting technology and market research, calls ADB “the biggest innovation in automotive lighting.” Although the share of cars equipped with ADB represents only 1 percent of the worldwide automotive market, Fratty estimates a jump to 15 percent by 2025.

　　Curiously, ADB is a mystery to most drivers in the United States. It’s banned in the U.S. because the Federal Motor Vehicle Safety Standards (FMVSS) bureau requires discrete high and low beam settings.

　　Technology suppliers, such as Lumileds, are hopeful that this will change soon.

　　ADB is currently under review by the National Highway Traffic Safety Administration (NHTSA), and some vendors expect it to be greenlighted in America in 2018, or by 2020 at the latest.

　　Why ADB now?

　　As retro as “headlight” technology might sound, ADB wouldn’t have emerged without the recent, rapid adoption of vehicles featuring Advanced Driving Assistance Systems (ADAS).

　　Phil Magney, founder and principal advisor for Vision Systems Intelligence (VSI), told EE Times, “I do take an interest in Adaptive Driving Beam even though it is not directly related to automated driving. What is interesting is that ADB requires the same resources as the safety systems, most notably the front facing camera.”

　　In a report issued by the Society of Automotive Engineers (SAE) last year to provide “test procedures, performance requirements, and design guidelines for ADB,” SAE concluded:

　　Recent advances in vehicle technologies have enabled active control of road illumination to the point that portions of a beam can be dimmed or removed based on inputs from the vehicle and/or its surroundings. This, coupled with advances in technologies used for lane departure warning, automatic high beam activation, and other functions has enabled the identification and location of other vehicle road users at night and to actively limit potentially glaring light to those vehicle road users.

　　Asked about technologies required for ADB, Magney said, “The systems employ a fairly sophisticated algorithm to make decisions about the illumination. You also need a powerful ECU that can run the algorithms and perform the calculations. You also need different cabling depending on what else those cameras are used for.”

　　Key players, technology innovation

　　There are about 10 key players in the ADB market, according to Fratty. They include “big four” automotive lighting suppliers Hella (Lippstadt, Germany), Koito Manufacturing (Tokyo), Valeo (Paris) and Automotive Lighting (Reutlingen, Germany).

　　“ADB is so important that many Tier Two’s and lighting technology suppliers are in a race to improve its resolution,” said Fratty. Lighting source technologies for ADB are rapidly progressing, he added, starting with mechanical shielding, LED matrix beam, DMD, LCD, μAFS and laser scanning.

　　In improving accuracy, lighting suppliers have been increasing the number of rows and columns of pixels used in matrix LED (each pixel equals one LED), according to Lumileds’ Vanderhaeghen. “We now have a range of solutions,” he said, from a matrix of 20 LEDs all the way to 84 LEDs. The Mercedes 2018 C-Class coupe launched at the LA AutoMobility show last week, for example, comes with the 84-LED module featuring Lumileds’ LUXEON Neo solution.

　　Striving to offer higher luminance, some engineers are exploring digital micromirror devices (DMD), on which a million pixels can be switched on and off. The resolution improved by DMD has also triggered the development of new applications, said Vanderhaeghen. “It can outline obstacles on the road or even read road signs,” he noted.

　　Other new technologies coming to ADB include μAFS, according to Fratty.

　　The μAFS project, supported by the German Federal Ministry of Education and Research, is a collaboration among Osram, Daimler, Fraunhofer, Hella and Infineon to develop a new innovative LED chip that can “take ADB to a new dimension.” The new LED chip contains 1,024 individually controllable pixels.

　　According to the German research alliance, “In the current generation of adaptive headlights on the market, several LED components are installed in the headlights side by side and on top of each other. Additional electronic components are required to switch light segments on and off. The number of segments is limited due to the restricted space in the headlight.” By using the new approach developed under the μAFS project, “electronic activation of the LED is now integrated in the chip, resulting in a much higher resolution, while still meeting limited space requirements,” the group said.

　　A year later, based on the μAFS project, Osram Opto Semiconductors completed the prototype of the world’s first hybrid LED, called Eviyos. The company described it as representing "major progress toward the first market-ready smart controllable high-resolution LED." Late September this year, Osram Specialty Lighting, which inegrated the prototype LED in a demonstrator, showed it off at a trade show ISAL in Germany.

　　When reached by EE Times, a spokeswoman at Osram said, "Many lighting manufacturers have expressed interest in the Eviyos, and are looking at this technology along with others to address the requirements of future ADB." However, she declined to discuss any further details on the commercial rollout plan.

　　Also, under development is laser scanning, which is able to scan quickly and switch on and off from left to right, up to down.

　　Asked about the timeline for each of those new technologies, Vanderhaeghen predicted that prototypes — such as DMD — designed to boost resolution and geared for top-end ADB should appear around 2019.  He doesn’t expect laser scanning to emerge until 2021. Meanwhile, he believes that LED matrix is likely to cover the biggest portion of the ADB market for the time being as a mainstream technology.

　　Fratty said that while light-source technology is important, the value is in ADB modules. “The value-add is in circuits and drivers combined in modules," Fratty said. Companies like Osram, Lumileds and Everlight are all aggressively competing, he added.

　　Why banned in the United States?

　　So, why is ADB banned in the United States?

　　Magney told us that the U.S. Federal Motor Vehicle Safety (FMVSS) [rule] 108 “does not allow ‘adaptive driving beam’ systems but does allow ‘beam switching systems' [often called adaptive headlamps], which are now pretty common on luxury cars.”

　　Adaptive driving beam systems, unlike switching systems, will adjust the beam to shield oncoming vehicles while illuminating the rest of the road. In contrast, “A beam switching system will dynamically switch between low and high beam and will block certain areas within the field of illumination,” explained Magney. “Both of these systems require the use of a front-facing camera that can read and classify oncoming vehicles.”

　　Asked why the U.S. regulator is taking so long to embrace ADB, Magney said, “The big hold-up is in the language that specifies a discrete high and low beam. The safety, testing and compliance is based on this.”

　　While the federal agency hasn’t nailed this yet, Magney noted, “They are supposed to update FMVSS 108 in the near future.”

　　On the other hand, Fratty suspects that the Europe-U.S. gap might stem from “commercial politics.” While Europe has several strong players in the automotive lighting market, the U.S. lags behind both Japan and Europe.

　　Lighting affects vehicle architecture

　　As Magney pointed out, ADB is interesting in a sense it is intricately tied to vehicle safety features. Vanderhaeghen acknowledged the close coordination required to make ADB work with cameras in a vehicle. LEDs in ADB need to be switched on and off according to images processed by cameras. “The data, once coded and identified, needs to be sent to a headlamp system, via CAN bus, for example, so that it can be translated into actions switching on and off on LED matrix array,” he said.

　　Magney agreed.  “You could not do adaptive headlamps without a front-facing camera and some intelligence.” He noted, “If the processing is done in the camera module then you could send the control signals over CAN bus without any trouble.”

　　However, if the camera — as in Tesla — has many things to watch out for, “you have to have a high-capacity cable” linking the camera to the processing domain. Magney cited the Gigabit Multimedia Serial Link (GMSL), FPD-Link and GB Ethernet.

　　Are there any advantages for ADB if lidar and headlights are integrated? Or will we see soon the integration of vision/headlamp systems?

　　Magney said, “The headlamp modules are great places to keep sensors because they are protected and kept clean and they are close to supporting electronics.”

　　However, as far as turning the headlamp into a giant lidar, “this may be a long shot in the near term,” he noted. “You need a lot of lumens to light up the road for a human.” On the other hand, he added, “if the vehicle were automated with no driver, you would not need all those lumens… The laser headlamps essentially become the lidar emitters at this point.”