Windshields May Do a Lot More Than Block Wind

Head-up displays (HUD) have been in use by military aircraft for decades, but like a lot of interesting technology developed for the military, they're moving into the commercial space. You can buy a Toyota Prius today with a small HUD that gives information about directions, lane changes, and fuel economy.

In spite of the rapid commercialization of this technology, there's still a long way to go. HUD screens are small-only about 6 in. wide-and they're flat, so they can't be integrated with the existing windshield.

Dr. Pierre-Alexandre Blanche, professor of optical sciences at University of Arizona (USA), is working to solve these problems. He proposes using a holographic collimator in combination with a holographic projector, which could create a much larger image that could eventually fill the entire field of view from inside an automobile. Moreover, this setup would be conformational, so the display surface could be integrated into a curved windshield.

"There is the possibility for the passenger to watch a movie through the windshield and for the driver to not see that movie, but instead see information for the road. It's entirely feasible with holographic technology," says Blanche.

However, we shouldn't expect to see full-windshield holographic entertainment systems in 2020 vehicle models, because these projection systems will require a display element that doesn't yet exist: a much larger number of pixels. The best-in-class display resolution is currently 4K with 8 million pixels, but it's not enough for a crisp hologram. We'll need at least 100 times that for full-windshield holographic images.

Nonetheless, Blanche points out that display technology evolved quickly from 780p to 4K resolution. "The next generation is going to be even better, and the generation after that is going to be holographic, I think," he says.

Watch his presentation at Optics + Photonics 2018 on the SPIE Digital Library: doi.org/10.1117/12.2507575