Today, drivers communicate their intentions to other drivers and pedestrians in various ways, such as turning on turn signals or using hand gestures. But what happens when there is no longer a driver in the driver's seat?
In this automotive feature, we cover TI's innovative transparent window display technology for the coming era of autonomous vehicles in the DLP auto display division


Contributed by: Jason Thompson, Manager, TI DLP Auto Display Division


The advent of autonomous vehicles is not far away. The signals used to convey vehicle information need to be expanded to enable more effective communication between vehicles and road users.

In particular, unmanned vehicles need more effective methods to convey vehicle information and driver intent, and display technology can become an important interface connecting the vehicle and its surroundings.

Today's automobiles are equipped with many types of displays. However, few of them are designed to communicate with the vehicle's surrounding environment. Transparent window display technology can be a solution.

Transparent window display technology helps pedestrians, cyclists, and drivers on the road understand the intentions of autonomous vehicles. There are several compelling reasons to expand deployment of vehicles equipped with transparent window display technology.

Signals visible from anywhere
Traffic signals have a long history, beginning with hand gestures and wooden signs. As cities grew, more cars, buses, pedestrians, and cyclists appeared on the roads.

Traffic lights for communication and control between road users also spread. But how do drivers communicate with each other or between drivers and pedestrians?

For nearly a century, automobiles have evolved from hand signals to light-based signals. Turn indicators are an example of the language drivers use today. Everyone understands a driver's intention when a turn signal flashes.

Until now, drivers had to manually activate turn signals to indicate their intentions. However, modern vehicles are equipped with sensors that support advanced driver assistance systems (ADAS), which automatically display signals to indicate the driver's intentions.

Now drivers no longer need to manually operate the signals. However, despite these advanced features, there are cases where pedestrians standing at a crosswalk require analog-style communication, such as making eye contact and waving—a capability autonomous vehicles cannot provide.

Autonomous vehicles and autonomous public transportation vehicles need to enhance the vehicle's exterior to display signals. For example, using a digital display, although an unmanned vehicle cannot speak, it can clearly communicate "go ahead" to pedestrians.

However, installing multiple external signaling devices on an ordinary vehicle not only takes up external space on the vehicle but also requires more wiring for design, increasing complexity.

Fortunately, vehicles already have several windows suitable for displaying signals. The combination of vehicle-certified projection display technology and new transparent films has made it possible to use existing vehicle windows for various forms of communication.

The new display shows the driver's intentions directly on the transparent window, allowing road users to communicate with unmanned vehicles and use them safely.

Transparent window display technology
Vehicle-certified transparent display solutions use the window surface to display detailed images and text, such as pedestrian crossing signals, visible to other drivers and pedestrians. It has significant potential to solve the communication challenges faced by unmanned vehicles.

By installing a compact vehicle-grade projector, information is displayed on the side, rear, or front window of the vehicle (see Figure 1). A transparent film layer embedded between multiple window panes enables information to be displayed on the transparent window.
Projector-based technology is already being used to enhance the driving experience. A prime example is augmented reality (AR) head-up display (HUD), which displays information on a vehicle's windshield. It can provide necessary information without distracting the driver while driving.

This light-based technology converts existing vehicle windows into displays when needed and provides transparent windows as usual when not needed. Vehicles can maintain their aesthetic appeal while the display device does not need to run continuously, resulting in very low power consumption.

Outlook
Transparent window displays are most likely to be applied in simple forms, enhancing signal transmission for information sharing between drivers or pedestrians. However, much more is possible.

Even before autonomous vehicles become widespread, transparent window displays could augment today's signaling technology and hand gestures to provide information.

Taxi services are likely to be early adopters of transparent window displays. Transparent window displays are a sure way to notify passengers that their called taxi has arrived.

Buses can also share information with other vehicles on the road and with passengers at bus stops or on the bus, such as information about the next stop or a stop signal lit on the rear window. Additionally, transparent window displays can serve as an important communication channel for weather warnings and other emergency situations.

Beyond displaying intentions and signals, both buses and taxis can use windows as a medium. They can display dynamic advertising that changes more easily than static displays. These next-generation advertising displays can be easily programmed.

Moreover, by using the vehicle's GPS data to deliver more sophisticated advertising to people in specific areas, revenue generation can be increased, providing significant benefits to new ride-sharing vehicles as well.

Advertising can also be provided to people riding in vehicles. Taxis, as well as hotels and airport shuttle buses, can provide travel information and infotainment, generating additional revenue streams.

In the not-too-distant future, robot taxis and autonomous public transportation are expected to become a reality. Once unmanned vehicles begin operating on roads, the language of communication needs to be expanded so that intentions can be effectively conveyed between drivers, pedestrians, and cyclists to maintain optimal traffic flow and safety.

Transparent window displays extend today's automobiles and provide a reliable and harmonious way for future vehicles to convey intentions even without a driver.