By on June 3, 2021

The problem with being in the sales business is the need to constantly outdo your rivals. Automakers know this better than just about anyone, which is why you see gimmicky features installed into vehicles that probably would have been just as good without them. But one never knows what’s going to catch on with consumers and you’ll never catch the big one if you don’t go fishing, so you’ll see patents filed on just about everything.

BMW has reportedly done just that with its new virtual mirror technology system that merges camera-based mirrors with olde-tyme projection technologies. The purpose appears to be something that replicates the experience of traditional side mirrors (which work fine) while adding some modern features that can only be accomplished using the newer stuff. 

First shared by the BMW i4Talk forum, Bavaria’s latest patent swaps side mirrors for cameras but ditches the video display they normally require for a partially opaque reflective section on the windows. Imagines are beamed from inside the cabin onto that area, giving an experience that can offer modern HUD features without the need for another screen. Drivers will also benefit from their cars becoming a wee bit more aerodynamic since there’s no need for exterior mirrors.

It’s an interesting concept. The patent filing (issued with the European Patent Office) makes it seem as though it’s not going to be taking up much cabin space and will be more intuitive for veteran drivers to transition into. But it does come with the obvious problem of not being able to roll down certain parts of your side windows. The patent details mention this, suggesting that the semi-mirrored glass could effectively be moved elsewhere and be made stationary. BMW also wants the ability to have the brightness be adjustable so that drivers can see clearly during daylight hours without also being blinded after sundown.

But it’s far from a perfect solution.

Our biggest qualm is that camera-based systems don’t allow you to modify your field of view by repositioning your head. This was a concern similarly shared by TheDrive and one that should be of particular concern to safety regulators. Camera systems provide a fixed perspective from wherever they’re installed, while mirrors allow you to owl your skull around to take in more of the road. It’s the kind of thing you don’t even think about until you’re sitting inside a vehicle wholly dependent upon cameras and realize something that sounds good on paper doesn’t always work out in practice.

Though the biggest issue is always that cameras add a needless amount of complexity to a system that has been mostly bulletproof since its inception. Blind-spot alerts have been a welcome inclusion (when they aren’t discouraging drivers from double-checking with a head turn) but they don’t really alter what side mirrors do. We also cannot imagine a world where side-mounted cameras with projectors will be cheaper to replace than a piece of reflective glass encased in plastic, nor one where they last longer or require less cleaning to ensure a faithful image.

But it’s not a problem in the United States because camera-based mirror systems aren’t legally allowed to supplant mirrors, even though it’s illegal for manufacturers not to equip vehicles without a video display that springs to life anytime you’re in reverse. Go figure.

[Image: sylv1rob1/Shutterstock; BMW/European Patent Office]

Get the latest TTAC e-Newsletter!

34 Comments on “BMW Patents Projection Side Mirror Display, Cool But Pointless...”

  • avatar

    Tim mentioned that there would be some changes. Maybe a post or two where you say, “Wow this new thing is amazing!” This constant drumbeat of negativity is tiring. If this is the editorial direction you’re getting from Tim, I’d say to Tim, “Maybe it wouldn’t be the worst idea to lighten the tone a little.”

    • 0 avatar

      “This constant drumbeat of negativity is tiring.”

    • 0 avatar

      Maybe if it were actually amazing. These have been thought of since the 90s and there is still a lot to work out.

      One thing I would do is project in each lower corner of the windshield and have the CCD way up front like some of the sports cars back in the 60s and 70s had. That way you have some perspective on where the car next to you really is.

      Then you have to find a way to keep water and ice off of the CCD because a couple water droplets on that will have a huge negative affect on clarity compared to a relatively large mirror.

  • avatar

    Superfluous Complexity
    The answer to a question no one asked.

    • 0 avatar

      @redapple: Superfluous Complexity

      Yeah, you should have seen the two-piece Continental tire valve stem I had to deal with. The stem!. Couldn’t figure out why I was losing air. The thing had loosened up and was leaking. But hey, you can take it apart and inspect the valve if you want. I suppose there are advantages, but how much time did they spend on the design? It’s beautiful though. A work of art.

    • 0 avatar

      “The answer to a question no one asked.”

      From the company that thought the PRNDLL wasn’t good enough.

  • avatar

    No need to use your imagination – go price a heated, auto dimming wing mirror on a BMW. And that’s just the glass. Add the power folding housing and it adds up.

    A projector might very well be cheaper, and less likely to take damage because of the lower profile. No auto dimming elements to fail either.

    • 0 avatar

      At basically retail a HD camera as a component is $7-$12. And that’s likely far higher than BMW would be paying when buying by the 100s of thousands. You’d have to compare that to the cost of a traditional mirror with heaters, motors to adjust, dimmers, etc.

  • avatar

    didn’t we discussed this 2-3 times already

  • avatar

    Side view mirrors are a significant source of aero drag (around 5% of total Cd on most cars). They also contribute to wind noise. Also worth noting, EU mirror regulations often drive requirements for larger mirrors than we have here in ‘Murica. That, or they can also drive the mirror into an aerodynamically bad location. Compare the mirrors on an EU Mustang vs the North American car. The bigger EU mirror isn’t there for the fun of it! Add in the ever-changing regulatory environment around things like mirror vision boxes, and it’s likely these things will be forced to get aerodynamically worse in the near future. We’ve been shrinking the aero impact of these for years, this is the next evolutionary step. We’re killing off the whip antenna for similar reasons. We picked all the aerodynamic low-hanging fruit years ago, now we’re on to harder stuff like this.

    Sincerely, random automotive aerodynamicist on the internet.

    • 0 avatar
      SCE to AUX

      Such devices won’t eliminate that 5% entirely, but only a fraction of it. Plus, total drag is – of course – the sum of aero drag and frictional drag. Then, overall efficiency is a function of the two drag loads plus the drivetrain losses.

      So I can’t see how the benefits of such a tiny improvement (maybe 1% overall) is worth the cost, complexity, and compromises (dirt, view angles, contamination, requirement to be powered).

      • 0 avatar

        1: A mirror is a bluff body, out of necessity. A small camera pod can be shaped into a more aerodynamic shape. Like, an aerodynamically negligible shape.

        2: Dirt is a problem with mirrors and windows too. Ditto for damage. Lots of cars driving around with damaged or missing side view glass. Vision angles are unlimited with a camera. Think long and hard about your line of sight from your eye to the mirror to the object you’re looking at. A camera simplifies it as the entire leg from the mirror to your eye is no longer relevant. Just point the camera where you want it, choose the amount of fish-eye desired (current mirrors already have that), and you’re done.

        3: See my comment about low-hanging fruit. Taking 5 to 10 counts out of a car is worth somewhere around $50 to $100 in CO2 per car, based on the current cost of credits. That puts camera mirrors into a financially viable position, which is the first gateway to production.

  • avatar

    FMVSS 111 is under review, so someday they could become legal. We might see it happen before the end of the year, but that’s pure speculation on my part.

  • avatar

    Hyundai puts the side-view / blind-spot image in the gauge cluster which is a pretty cool trick since it doesn’t require any fancy technology.

  • avatar
    SCE to AUX

    “cameras add a needless amount of complexity to a system that has been mostly bulletproof since its inception”


    Sorry, but the aerodynamic benefits of these devices are not worth the compromises.

    • 0 avatar

      Given the greenhouse (or lack thereof) in modern vehicles cameras are almost mandatory it seems. Camera and screen tech has gotten to the point where it isn’t that complex or expensive. However this BMW system does seem overly complicated.

      One advantage to a side-mirror-less vehicle is eliminating the first thing that smacks the garage when pulling out.

  • avatar

    Why is a side mirror so hard? Of all the things to focus R&D on, side mirrors are tools of the devil and must go?

  • avatar

    This either shows vision or lack of it! Probably being $2K in replacement cost, I’m going for the latter!

  • avatar
    Tele Vision


    Eye-tracking tech is already extant in some BMW/Cadillac/Subaru cars. Retractable mirrors abound. I wouldn’t think that it would be impossible to have regular side mirrors that are able to very quickly deploy when the driver looks at them, then retract when the driver looks away. Perhaps this would only be operational at the higher speeds at which drag becomes manifest, as drag squares with speed.

    Having a slippery, furled design of a side mirror that’s a comparative sail when deployed might just satisfy all concerns and concerned.

    The automatic default fail would, of course, be ‘deployed’ and not ‘retracted’, with the ability to manually override the actuation to deploy the mirrors without damaging the mechanism.

    Random Thoughts have been brought to you all by Beck’s beer and hot weather.

    • 0 avatar

      Good points, though I wouldn’t be surprised if government regulations prevented mirrors from being deployable. Similar to how brake lights (in the US) can’t be on a moving surface like the trunk lid or tail gate.

      Another small issue, assuming deployable mirrors are legal, is how to apply their benefit to the final EPA fuel economy test. For example, Dodge and Ford trucks both have deployable air dams. I’m pretty sure that in order to claim the aero benefit for that part, you have to prove that it’s deployed through most or all of the EPA test. That’s easy enough, as you can just force it to be deployed any time the truck is going above X speed. A deployable mirror based on driver behavior is a little more complicated! Would the EPA define the amount of time and at what speeds you need to look into your mirrors? Maybe… but I really wouldn’t want to government to dictate that to me!

      At the end of the day, good cameras and good screens are getting shockingly cheap. Cheap is the name of the game in the auto industry. They rarely ask “how much better can we make this” but they ALWAYS ask “how much cost can we take out of this”!

  • avatar

    Regular mirror provides true 3D holographic image with 64k UHD image. Cannot beat that!

  • avatar
    Jeff S

    This is going to be very expensive especially replacement costs. I would trust the Japanese more to make this system reliable than BMW or any German manufacturer. BMW has mastered the art of making expensive to maintain and repair vehicles. Eventually BMWs with this feature will end up in the used car market and those owners will more likely not fix or replace this once it is broken. Bad enough that many drivers don’t pay attention but if they cannot see vehicles beside them when they decide to change lanes due to broken side projection mirrors then this will be a disaster.

  • avatar

    Haha- Technology isn’t always your friend. Just another doo-dad to emulate (poorly) an existing low-tech solution. Sort of in the category of huge digital displays that actually emulate the low-tech dials they replaced! Or digital radio displays that replicate NIXIE TUBES. Technology for the sake of technology is bad practice- especially when it attempts to improve low-tech solutions that work. 2 cents please.

  • avatar

    You just can’t beat the German mantra of “why make it simple when we can make it complicated”.

  • avatar

    Hopefully, British cars won’t have Lucas mirrors.

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • Jeff S: I did something similar to hypermilling during the Arab Oil Embargo of 1973 with my parents 64 Impala wagon...
  • Art Vandelay: You have nothing to refute with respect to what he says, so you just attack the person. Typical.
  • Jeff S: @Dave M.–He is just part of the Trumpers who are told to go out and spread the big lie that the...
  • EBFlex: “According to a T-shirt I saw a young man wearing on June 19th at church celebrating the 4th of July...
  • EBFlex: “His keyboard doesn’t have spell- or IQ-check.” “Certainly no IQ check. But probably an...

New Car Research

Get a Free Dealer Quote

Who We Are

  • Adam Tonge
  • Bozi Tatarevic
  • Corey Lewis
  • Jo Borras
  • Mark Baruth
  • Ronnie Schreiber