General Motors has been awarded a patent from the U.S. Patent and Trademark Office for a windshield capable of dimming when experiencing excessive glare from oncoming vehicles. When paired with an augmented reality heads-up display (HUD), the system also highlights approaching vehicles.

Once the windshield identifies an oncoming vehicle within a predetermined distance from the host vehicle, it then determines whether that vehicle’s headlights are active. After determining the intensity of the headlights by comparing the incoming beam to a pre-determined threshold, “at least a portion” of the windshield dims.
Published on January 17, 2023, and originally filed in July 2022, the patent from GM Global Technology Operations notes that light emitted from the headlights of oncoming traffic may cause excessive glare. According to GM, that glare can make driving challenging for motorists.
“It is therefore desirable to develop a system and a method that can minimize the effects of excessive glare while driving,” GM writes in the patent.
When the windshield identifies bright lights, such as headlights, appropriate locations of the windshield dim to shade the driver’s eyes from excessive glare. That’s accomplished through the use of smart glass with electrically-tunable transmittance capabilities.
Once the windshield identifies an oncoming vehicle within a predetermined distance from the host vehicle, it then determines whether that vehicle’s headlights are active. After determining the intensity of the headlights by comparing the incoming beam to a pre-determined threshold, “at least a portion” of the windshield dims.
“The smart glass includes a plurality of segments,” the patent reads. “Each of the plurality of segments is individually configured to transition between an opaque state and a transparent state independently of other segments. The method further includes determining which of the segments of the smart glass have to be dimmed to cover the light beam …”
Visible light cannot pass through the windshield while portions are in the opaque state, while visible light can path through portions of the windshield in a transparent state.
The system then highlights the other vehicle to “maintain the driver’s awareness of the remote vehicle’s presence and real-time location,” as well as generates a virtual image of the vehicle on the display, according to the application. The image includes a “bounding box” that surrounds the oncoming vehicle, with those capabilities made possible by tracking the user’s eye position and movement.