AR-HUD helps improve driver and passenger safety

As cars become more electrified and connected, the future of head-up displays (HUDs) is changing rapidly. In particular, augmented reality (AR-HUDs) have become a core element of smart cockpit design, helping to enhance the overall driving experience through driver assistance and safety features. When designing the next generation of AR-HUDs, there are several technical points to keep in mind.

Field of View (FOV) and Virtual Image Distance

Field of view is perhaps one of the most important parameters for an AR-HUD solution, as it directly affects the size of the image the driver sees. DLP® technology, such as the DLP4620S-Q1 DMD, can achieve a field of view of more than 15 degrees, allowing information to be projected across multiple lanes for the driver.

The virtual image distance indicates the projection distance of the image, and how far ahead the driver can see the projected image. This is particularly important at high speeds, as the driver needs to be aware of road obstacles and other situations in advance. More importantly, a longer virtual imaging distance (greater than 7.5m) can greatly reduce the dizziness caused by the driver's focus switching between the HUD and the actual scene image (Convergence); offset the movement parallax (Movement Parallax) caused by vehicle vibration, driver posture adjustment, etc., so as to more accurately perform AR fusion, enhance the driving experience, and ensure driving safety. The current AR-HUD design using DLP chips can project images 2 to 20 meters in front of the driver, which can significantly expand the virtual image distance compared to traditional HUDs, as shown in Figure 1.

Figure 1. AR-HUD image distance range using DLP technology

Image Quality

It is important to note that in this case, good image quality does not equate to higher resolution. Image quality is related to multiple variables, including image refresh rate, color depth, brightness, etc. Unlike the local movie theater, controlling image quality in the chaotic and even unpredictable outdoor environment of the car is very challenging. The lighting is different during the day and at night, so the automotive AR-HUD solution must be able to accurately maintain color depth and consistent high contrast to properly project in various driving conditions.

For example, our DLP4620S-Q1 automotive-qualified chipset can be used with LEDs or lasers and optical systems to achieve highly saturated colors up to 125% of the NTSC color gamut. The DMD can also achieve ultra-high brightness of more than 15,000cd/m2 and a high dynamic dimming ratio of more than 5000:1. With the new FMV (filled mirror via) pixel process, the DLP4620S-Q1 can further improve the contrast by >35% without changing the system design. These feature combinations help provide drivers with vivid images in various environments.

Development Options

For most automotive AR-HUD solutions, multiple developers need to collaborate to meet product and customer needs. AR-HUD solutions are part of an integrated solution that also includes advanced driver assistance systems (ADAS) and other parts that work together to provide a better driving experience.

TI has valuable development experience and the TI Design Network of relevant partners to help develop products and services for TI's various semiconductor device solutions.

Conclusion

AR-HUD can project all relevant data (such as speed and road obstacles) with the windshield as the focal point, while allowing the driver to focus on the road ahead. As cars continue to become more connected, AR-HUD can help improve driver and passenger safety and improve the overall driving experience. DLP technology will also continue to enable high-performance resolution, brightness, efficiency, contrast, and color, helping automotive designers design the next generation of AR-HUD.