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Car mirror copies eyeglasses to eliminate blind spots

By

January 28, 2013

A conventional flat mirror (left) and the progressive mirror

A conventional flat mirror (left) and the progressive mirror

Usually when we hear the term “progressive optics” it’s in reference to bi- or trifocal glasses, that don’t have sharp lines between the different focal zones of the lenses. A group of scientists from Korea and the US, however, have recently used the technology to create something else – a prototype driver’s side car mirror that has no blind spot, yet that also doesn’t distort images in an unsafe manner.

As things currently stand – in North America, at least – only passenger-side mirrors are allowed to have a “fish eye”-type wide-angle distortion. Because that distortion causes other vehicles to appear farther away than they actually are, driver’s side mirrors are required to be flat and distortion-free. As a result, those mirrors may provide a more accurate impression of how close other vehicles are, but they also lose sight of those cars when they enter the infamous blind spot.

One solution is to add a smaller wide-angle mirror to one corner of the driver’s side mirror, but many drivers find that such add-ons ultimately just block their view of the main mirror. Instead, Hocheol Lee and Dohyun Kim at Korea’s Hanbat National University, and Sung Yi at Portland State University, looked to progressive optics.

In eyeglasses, the different focal zones are layered one above the other. The prototype mirror, however, features three different curvatures that are arranged side-by-side. The inner zone is curved to allow for distance viewing, the outer zone is optimized for close-up viewing, and the middle zone serves as a transition between the two. As a result, the mirror has no blind spot – by the time an approaching vehicle passes off the outer edge of the mirror, it’s already visible in the driver’s peripheral vision.

Unfortunately there is some distortion of images, although the researchers believe that this is an acceptable trade-off for the benefits offered by the mirror. Importantly, the distortions do not result in other vehicles looking closer or more distant than they actually are.

Although the mirror is currently still a prototype, the researchers have stated that it would be less expensive to manufacture than conventional mirrors with added wide-angle lenses. A paper on the research was recently published in the journal Optics Letters.

Another low-distortion anti-blind-spot driver’s side mirror, that utilizes a surface made up of multiple smaller mirrors turned to different angles, is under development at Philadelphia’s Drexel University.

Source: The Optical Society

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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10 Comments

On most cars you can effectively remove the blind spot by moving the flat mirror to the front corner of the car.

Slowburn
28th January, 2013 @ 05:16 pm PST

I definitely want that in my next car. It is way cool and makes it safer when driving.

BigGoofyGuy
28th January, 2013 @ 05:46 pm PST

It is amazing that we have autonomous cars and this much technology available but I still ask my passengers to double check my blind spots for me in city traffic.

Daishi
28th January, 2013 @ 07:45 pm PST

In the U.K. convex mirrors are allowed on the driver's side. It's a real convenience being able to do away with the blind spot. Somehow, the Brits manage to understand that the image is distorted.

Roy Murray
29th January, 2013 @ 05:47 am PST

The "blind spot" is a myth, fostered by people who should know better. While such a thing did exist back when car mirrors were (1) small, (2) non convex and (3) only on the driver's side prior to the 50s, they really ceased to be when multiple mirrors were permitted, englarged and had the ability to be convex. What is really happening is that most drivers are never taught how to adjust their mirrors, generally keeping the side view mirrors where they can see the back end...of their own car, hardly useful. But moving those mirrors out further, on both sides, the "blind spots", are completely removed. It also gets rid of the rather dangerous and stupid concept of turning one's head over one's shoulder (demanded in some states in the US) to check for close cars. That manages to completely take your eyes off the road in front of you, dangerous in the extreme. Just shifting your eyes back to the front leaves an additional time while first your eyes, then your brain, readjust to the "new" sight picture. Total idiocy.

TheRogue1000
29th January, 2013 @ 09:31 am PST

Roy Murray;

Agreed, I've never had a problem with convex mirrors (both sides) driving here in the UK. When I started driving all external car mirrors were flat..oh yeh & the man with the red warning flag walking in front of the car!

The introduction of convex mirrors actually helped greatly with road safety....that is of course providing the driver uses them! It's quite disturbing having to cope with a flat driver's side mirror driving in the US, time to consider a legislation change?

Get Ralph (Unsafe At Any Speed) Nader on the case.

Zarbi
29th January, 2013 @ 10:32 am PST

Ditto, TheRouge1000. Years ago I ran across this argument, and part of it was when you adjusted the side mirrors to just barely not include your own car, you duplicated much of the view your inside rearview mirror covers. I still adjust my mirrors the wrong way, not having sat down with tape measure & drawn up coverages to find out where I should adjust the mirrors by some belt and suspenders procedure, for the particular car I am driving at the time. Google hit at this time for "proper adjustment of sideview mirrors, comes up with this:



A little more concrete but still not (for me) inspiring confidence in the knowledge I'll have the mirrors pointed for needed coverage, just by following the video's direction. I'll have to to either do the measuring or back up to a wall with some reference points on it, aim the mirrors to my satisfacttion and then go back and see where I need to locate my head to see the rear corners of the car when the mirrors are correctly adjusted for any particular car.

Dave B13
29th January, 2013 @ 11:43 am PST

Great project, it would be nice to have this on all cars.

I do agree that on many cars proper adjustment can eliminate the spot, but it's not equally true for all cars.

Also, just watching what people do when using technology, it becomes clear that in many instances they don't understand (or weren't shown) how things work in the first place.

In cars, blowers/heaters come to mind. People turning the fan off instead of the heat down, and then wiping their windows with a cloth, gaining a tiny arrowslit to peek through. Or on bikes, LED tail lights, many people don't understand these things have to be aimed correctly due to the small angle of the light flux cone. How to show, when to show, tricky stuff. Driving schools could be doing this.

BeWalt
29th January, 2013 @ 02:12 pm PST

They've had mirrors like this for motorcycles for some time. It must have been about two-and-a-half years ago I helped a friend install one on his bike.

Shadowmerlin
29th January, 2013 @ 07:57 pm PST

I had a 2006 Renault Kangoo (RHD) and the left side rear view mirror had a compound convexity so that at the outer edge the mirror showed cars that I could see out the window. I suppose that if I bought a left side mirror and stuck it into the drivers side it would once and for all elliminate the blind spot.

Law makers are tunnel visioned and fail to realise that some (most) people can adjust to the curve of a convex mirror with out pproblem. I even reverse a trailer by the odd mirrors.

pointyup
12th February, 2013 @ 01:46 am PST
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