Digital rear view mirrors modernize an old standard
The rear-view mirror, which sits at the center of the windshield and looks through the vehicle and its back window, hasn’t changed much since first being introduced. They've remained essentially unchanged for around 100 years, but now the humble rear-view mirror is entering the 21st century with an increasing number of vehicles now featuring digital rear-view mirrors that use rear-facing cameras and in-mirror displays to show what’s behind the vehicle.
Back in 1906, a Frenchman named Henri Cain submitted a convex mirror, to be mounted on the dashboard of a car, for patent. That mirror, with a few modifications over time, has remained the norm for automotive to this day. The new digital mirrors are meant to solve the biggest problems with Cain’s rear-view design, especially in bigger vehicles, such as the “tunnel vision” offered by big vehicle cabins and the view often being blocked by objects within the cabin.
A recent road trip highlighted such problems. Our family packed into a big 2019 Infiniti QX80 SUV, added camping gear, and headed to Devil’s Tower in Wyoming. Once all three kids and both adults were inside the Infiniti, the problem of the blocked rear-view became apparent. With three rows of seating deployed and a lot of gear stashed throughout the cabin and packed into the cargo area, the rear window was completely blocked. The driver’s view from the rear-view mirror was nothing but a wall of sleeping bags. Until the mirror was flipped.
Using the lever normally meant for tilting the mirror down to reduce headlight glare from following vehicles at night, the mirror transformed from a simple reflective surface to a high-resolution LCD screen that showed a real-time camera view from the back of the vehicle. The camera, mounted higher on the tailgate than the standard backup camera for parking, gives a view similar to that of the mirror-based rear-view, but without the cabin interior’s interference.
Since that road trip in the 2019 QX80, we’ve seen that same system in action in a Nissan Armada and a Chevrolet Traverse. Both Nissan and General Motors have the digital rear-view camera in place in several large vehicles, mostly sport utilities.
Why hasn’t a digital rear-view been offered on production vehicles before this? And what are the implications of one now? We reached out to Infiniti and spoke with Sean McNamara, Senior Manager of Product Planning for the QX80. According to him, there were regulatory questions to be answered as well as costs and implementation challenges to be overcome.
In many markets, specifically in the United States, regulations prohibit any screen facing the driver from showing moving content. This regulation was created for safety reasons, requiring manufacturers to block videos or similar distractions from being played on the infotainment screens in cars and trucks. McNamara said that the intent of the regulation was clear, but the wording was not, so many automakers were a bit reluctant to add a screen that cast a camera view into the vehicle.
"Many of us manufacturers all came to the same conclusion at about the same time,” McNamara says. That conclusion? The risk was worth the potential reward. With the system now in place in several makes and models, it appears likely that federal regulators in North America view it the same way.
The camera-based system offers advantages for the driver on several fronts. Not only does it allow the driver to “see through” the interior of the vehicle, regardless of obstacles between the mirror and the rear window, but it also improves visibility in low-light conditions and reduces headlight glare at night.
The Infiniti system uses a 98-pixels per inch, 0.36-megapixel camera with 100 dB of dynamic range. The image from this camera is sent to a 1,280 x 300-pixel-resolution LCD screen built into the rear-view mirror of the vehicle. The camera on Nissan and Infiniti systems for the digital rear-view mirror is separate from the backup camera. This is also the case on General Motors vehicles with a similar system.
In the 2019 QX80, for example, the backup camera is located just above the license plate while the rear-view mirror’s camera is located in the rear spoiler above the rear window glass. The cost of the camera system is difficult to discern, it being included as standard equipment in the QX80’s Limited trim level and as standard in the Armada’s Platinum trim. GM likewise packages its digital rear-view in trim points rather than à la carte.
Yet it’s clear that the costs associated with the extra camera and the integrated LCD screen in the rear-view are not as high as they once might have been. The mirror, for example, is an extended version of a low-cost rear-view mirror being used in other makes such as Toyota and Subaru, which add a small LCD screen to a portion of the rear-view mirror to show the backup camera view when in reverse.
As more manufacturers begin taking up the idea of a smarter rear-view mirror, the digital rear-view seen in Chevrolet, Infiniti, and Nissan vehicles could become the norm. On our family road trip in the 2019 Infiniti QX80 this summer, the benefits of the camera-based rear-view system were clear.