Adaptive Driving Beams: Safer, Smarter Headlights for Improved Safety

Alex Christian, Senior Field Applications Engineer at Samsung Semiconductor Automotive lighting technology is one of my favorite topics, and by the looks of our social media, I’m not alone in the habit of geeky out over headlamps. Our last post on adaptive driving beams got a lot of attention from readers, and plenty of comments on Facebook, including a few discussions about what “smart headlights” actually are. I can tell you what they aren’t: smart headlights aren’t the simple auto-off high/low beams that some high-end cars in the U.S. have. While refraining from blinding oncoming traffic with bright lights is a good thing, this relatively simple technology doesn’t fall under “smart” lighting[1]. Smart headlights provide much more sophisticated functionality. So, let’s define it. First, although not everyone will agree with this, I consider the term “smart headlights” largely interchangeable with the term we use in the lighting industry, “adaptive driving beams,” or ADB for short. With ADB systems, your high beams are ALWAYS on. Instead of switching from high beam to low when another car is approaching, ADBs will turn off sections of the headlight, carving out an unilluminated area around oncoming vehicles (and highly reflective objects, like road signs, so that you’re not blinded). Why always-on high beams? At night, high beams are a driver’s best friend. According to the American Automotive Association, ADB systems can increase roadway lighting by over 80%—that’d be a significant advantage for drivers. How ADBs work Rather than a standard “bulb” that you’re probably used to seeing in vehicles, ADBs are constructed from LED panels. Samsung makes PixCell, which is an excellent example of a high-end LED lighting package for ADB systems. We use LEDs because they are flexible and produce a high luminous flux—the perceived amount of light emitted from a light source.

LEDs give us a high degree of optical control, using significantly less power than traditional incandescent or halogen bulbs, and they can do all of this with a small footprint. You might not think that LED size matters, but car designers are very conscious of how vehicle design affects branding. Newer car designs are sleek—with fuel efficiency standards and new electric cars, designers are opting for aerodynamic body shapes and reduced weight—so, if we can deliver a high-performing lighting cell that takes up less room, it gives designers flexibility. It also provides outstanding illumination that drastically improves road safety. ADB systems use cameras mounted around the car’s exterior, controlled by a super-fast, central processor). There’s also intricate firmware that can determine the positions of other objects as detected by the external cameras (or an array of systems combined with cameras, such as sensors, lidar, etc. The system identifies the objects like oncoming cars and trucks, or other vehicles that are ahead of you, where you don’t want to direct a really bright, glaring light—and continuously, dynamically adjusts lit-up sections, in fractions of a second, so that the darkened sections “follow” the line of sight of other vehicles. Why PixCell is particularly brilliant[2] Samsung’s PixCell is what we call a segmented light source. Generally, when ADB packages are manufactured, each source is cut individually from a wafer and assembled into discrete LED packages, which in turn are built, one pixel at a time, or one LED at a time, onto a circuit board, creating an array of LEDs. With PixCell, we manufacture the entire light array at the wafer level. This lets us cut an entire section of the wafer and assemble it as a single large piece (after some post-processing) directly on a circuit board. This process allows us to space the pixels closer together. Large spaces between lighting pixels are not ideal because they can reduce contrast ratio and create dead zones. Dead zones are permanently “off” or “dark” spaces between pixels. We then have to compensate for those dark blobs using more complex optics technology, which increases the cost, size and weight of the overall lighting package. While discrete LED solutions might have, at best, a pixel-to-pixel spacing of 60-70um, Samsung PixCell’s spacing is only 25um, which makes them less complex and more compact compared to individually assembled LEDs assembled in other systems.

Another advantage of our design is that PixCell has a high contrast ratio due to decreased light trespass. LEDs are made with phosphor, which—and this is an overly simplified statement—takes blue light and turns it white. When we manufacture PixCell’s array of LEDs, we place them very close together. And phosphor is extremely excitable; it takes very little to stimulate it. If an LED pixel is turned on, its light energy can trespass into the neighboring pixel’s phosphor, making the neighboring LED glow slightly. This glow has a detrimental effect on the LED’s contrast ratio because the cut-off point for the lighted area should be very distinct. This is where the wafer-level manufacturing comes in; it’s the same type of process used for highly complex, tiny semiconductors, which allows us to manage spacing with repeatable consistency. Where can you get an ADB system? Right now, you might be wondering, where do I get these amazing headlights? I’ve got two pieces of bad news: first, ADBs aren’t an after-market option, so they will only be available in newer passenger vehicles. Second, ADB systems are not yet legal in the United States. While they are legal in Canada, Europe and other parts of the world, there have been regulatory obstacles in approving ADB systems in the U.S. The reason is a bit complex—it boils down to automotive regulations that have not been updated in decades. Fortunately, there seems to be light at the end of the tunnel[3]. The Build Back Better legislation stipulates that a final decision on ADB technology be made within the next two years. PixCell can be used installed in cars built for the American market because PixCell is designed with two different modes. There’s matrix mode (that’s the adaptive solution we’ve been describing) and static mode, which is standard high/low beam functionality. Technically speaking, car manufacturers can purchase the PixCell package and turn off the matrix mode for cars sold in the United States. Once ADB systems become legal in the United States, OEMs can enable matrix mode features through dealer programming, or in certain cases, using over-the-air software and firmware updates. It’s my sincere hope that the federal government legalizes ADB systems quickly. Consumer Reports estimates that, when driving at 60 mph, drivers need about 308 feet to stop for an obstacle. High beams provide an additional 250 feet of road illumination, yet up to 64% of drivers don’t use their high beams while driving at night, and roughly 30% of driving accidents happen at night (even though fewer drivers are on the road during nighttime hours). This isn’t about promoting Samsung technology (although you have to admit, our technology is really cool), it’s about saving lives. Adaptive driving beams give us the opportunity to improve nighttime driving visibility and drastically reduce traffic accidents; I think that a cause we can all get behind. [1] Also, the whole “high/low beam” switching means that you go from having your high beams on, which gives you really god visibility, until they turn off—then you’re back to your standard beams, and your eyes have to adjust, which means a couple of seconds during which your nighttime visibility is rather poor until your pupils can dilate. [2] Was that a pun? Yes. Yes, it was. [3] Another pun? I believe so.