The topic of driver distraction is one we’ve covered a lot here at Ars. Whether due to the proliferation of smartphones, touchscreen infotainment systems that are now fitted to most new cars, or people simply not paying attention, the National Highway Traffic Safety Administration estimates that 400,000 people were injured and 2,841 killed as a result of distracted drivers in 2018.
Researchers are split as to whether the real problem is cognitive overload or drivers simply not having their eyes on the road ahead, with some automakers and technology companies trying to tackle the second issue through the use of gaze-tracking driver monitoring systems. But a new technology demoed by Texas Instruments at this year’s (virtual) CES might mean there’s much less reason for drivers to take their eyes off the road ahead.
Specifically, the tech uses a small projector embedded in the car’s dashboard and a layer of holographic film laminated within the sandwich of glass that makes up a windshield to project an in-plane hologram of the car’s instrument cluster and navigation directly into the driver’s line of sight.
Heads-up displays have been available in cars (both high and low end) for many years now, and at CES in 2019, Ars saw a demo of a full-windshield augmented reality HUD. However, TI’s new system, which it’s calling an in-plane holographic optical element (IP HOE) display, is subtly different from current HUD technology. For one thing, as the name suggests, the display is projected in the plane of the windshield—in contrast, a HUD’s image appears to float out in space several feet ahead of the vehicle.
TI says that the primary advantage of the IP HOE display is that it requires much less space than the large mirrors required by a traditional HUD. TI claims that the IP HOE display can be supported using a small projector of less than 1L (0.03 cubic feet) in volume, compared to 20L (0.7 cubic feet) or more for a similar-sized display using HUD technology.
Additionally, you can have much more freedom when it comes to fitting the IP HOE projector in a car’s dash. Since the images can be projected off-axis, the projector does not need to be mounted directly between the driver and the windshield. TI says that this makes it a good option for vehicles like sports cars, which have limited dash space and steeply raked windshields, as well as commercial heavy trucks, which have near-vertical windshields, neither of which makes them good candidates for current HUD technology.
Unlike the full-windshield AR HUD I saw in 2019, the IP HOE display is able to use RGB LEDs instead of lasers for illumination, which means it’s cheaper, more reliable, and requires no active cooling. The display is even compatible with drivers wearing polarized sunglasses.
Note that the IP HOE display is not an augmented reality display like the one Mercedes-Benz is debuting in its latest S-Class sedan. As you can see from the embedded video above, it’s showing the same information as a main instrument display, but there’s no real-time object identification and flagging.
It’s not entirely perfect, however. For one thing, the image distance to the IP HOE display is short from the driver’s eyes to the windshield; a HUD typically has an image distance of between 7.5 to 20 feet (2.2-6.1m). But the IP HOE has a similar image distance to the main instrument clusters fitted to the cars that all of us currently drive, and since it is projecting the display in the same plane as the road ahead, there should be much less accommodation time for the driver, which means a quicker reaction time to any incidents that occur ahead.