How an Electronic Sun Visor Works

Even a mediocre sun visor is preferable to none at all.
Courtesy of Christopher Ziemnowicz

Sun visors used to be simple -- a scrap of fiberboard covered with vinyl or fabric, attached to a hinge. The hinge allowed the visor to flip down, blocking direct head-on sunlight, to the side window, or up and out of the way. Most had mirrors. The fancy ones had mirrors that would light up. And many were accessorized by the auto equivalent of a fanny pack -- a piece of ungainly slotted felt, designed to hold 8 or 9 CDs, that strapped on the visor with Velcro.

And that was it, really, and consumers seemed reasonably satisfied. As long as a sun visor blocked some of the sun's blinding rays, it had served its purpose. A mediocre sun visor was preferable to none at all. There was always room for improvement, but there was also a line that could not be crossed -- blocking enough sun to see clearly, while leaving enough of the windshield unobstructed so that a driver could see the road and avoid obstacles.


But as far as automotive designers and aftermarket electronics manufacturers are concerned, anything can be improved. Even if it turns out the improvements aren't exactly necessary. And even if consumers later discover that the improvements might not have been plausible, after all.

The Aftermarket Accessory

The center console can feel a little crowded nowadays. Ever since consumers decided that every electronic control requires a touchscreen panel, and auto designers complied with those wishes, a car's center stack is beginning to feel a little complicated. We've seen these screens dominate cockpits from luxury sedans and SUVs all the way down to budget compacts. If you've got a car with one of these in-dash computer systems, you might be wondering what's left to deck out. And if you've got an older or less expensive car, you might be searching for affordable alternatives.

So, it's inevitable that electronics designers would start eyeing a previously underutilized bit of surface area -- the sun visor. And, hey, a sun visor can be made just big enough to cram in a 7-inch LCD monitor and a DVD drive. Problem solved!


Some of these aftermarket electronic sun visors can be had for less than $100, and manufacturers claim they're pretty easy to install in most cars, by simply swapping out the stock sun visor (but only on the passenger side, please!) and hooking up the new one. They come in a range of neutrals -- plastic black, plastic gray and plastic beige -- to coordinate (somewhat) with most interiors, and some even include additional features like USB input slots and GPS systems.

DVD player sun visors appear to have been invented to solve a problem that's about two decades old -- how to enjoy film and television in a moving vehicle (on a very tight budget). But hey, the bulkiness and heft of the plastic might block out a bit more sun than the old visor, right?

At best, this is a super inexpensive way to get a DVD player in your car -- that is, if you've got an older car and a desperate passenger, and watching movies on an iPod, smartphone or tablet isn't an option for whatever reason. At worst, well ... it's a sun visor and it's electronic, but in terms of what we need a sun visor to do, it just isn't the kind of electronic sun visor anyone really had in mind.


The Matrix

There's simply no sun visor that can extend low enough to shield the sun's rays from your eyes at sunrise and sunset. But wouldn't it be nice if you could somehow safely reduce the glare?
Courtesy of Chris Downer

In theory, some of the technologies used for smart windows would be applicable. Photochromatic glass, which darkens when exposed to sunlight, seems like it would be a good way to make windshields more effective. And it's true that photochromatic technology and other similar smart glass products are already being used in cars. But auto manufacturers seem hesitant to employ anything more complicated -- after all, the main purpose of a windshield is safety, and the strength and shatter-resistant properties of the glass can't be compromised.

However, a solution known as suspended particle devices could be adapted for use in sun visors. Suspended particle devices function like a valve that lets light pass through. Millions of these particles float in a material between two panes of glass (or plastic, in some cases). A control module allows the user to decide how much light to allow to pass through. If full light is desired, the particles are arranged in rows so the sun's rays have a pathway through. To block light, the particles are scattered.


Some companies have tried to put similar ideas into effect. One such product that was once in development was a clear electronic panel that could descend from the car's regular sun visor. In addition to blocking the sun at the brightest times of day, it was also designed to be used at night to reduce headlight glare from surrounding traffic. YES Invent, a development firm based in Israel, claims their visor monitors the driver's eyes to figure out how much glare reduction is necessary and then automatically adjusts accordingly. The price was projected to be less than $300, and YES Invent hoped it would be widely adopted by automotive manufacturers ... but it hasn't happened yet.

Back in 2007, Popular Mechanics and some blogs reported that Volkswagen was working on another system, kind of a combination of the two aforementioned concepts. It used the same sunlight sensors and driver's-eye sensors as the YES Invent's anti-glare visor, but the components were actually embedded into the windshield itself to offer protection in the areas that a regular sun visor simply can't block. It produced a dark spot in the glass that reacted swiftly to changing light and could even move when the car turned. It's reasonable to assume that the system, if ever completed, would have ended up in the Volkswagen group's more upscale models (like Audi, for example) but so far, the electronic matrix sun visor (as it was called back then) has yet to be seen.


Lots More Information

Author's Note: How an Electronic Sun Visor Works

As best as I could tell, it seems like auto researchers have decided sun glare just isn't that much of a problem anymore. Projects in development appear to have been abandoned, and sun visors don't seem much more advanced than they did the last time I drove a new car. The sun's still there, so it's hard to figure out why auto manufacturers think drivers no longer need glare protection. It's probably worth mentioning that anti-glare features on tablets and e-readers is rather impressive now, though -- we certainly don't recommend reading in traffic, but it would probably be easier on the eyes.

Related Articles

  • Filipponio, Frank. "VW developing electronic sun-visor embedded in windshield." July 20, 2007. (Jan. 30, 2013)
  • "Sun Visor Car DVD Players." (Jan. 30, 2013)
  • "Top Ten Unusual Auto Add-Ons." (Jan. 30, 2013),3253,l=201296&a=201296&po=1,00.asp
  • YES !nvent. "Electronic Sun Visor - Automotive Glare Reduction System for Enhanced Vision." (Jan. 30, 2013)