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Tinted Windshield

Turn your windshield tint on and off.
  (+9, -1)(+9, -1)
(+9, -1)
  [vote for,
against]

It gets hot here in Northern Oklahoma. Real hot. Lots of people have tinted window glass, except for the front windshield for obvious reasons. So we tote around those sun shield things to keep the sun from pouring in the front of the car.

I don't like my sun shield. I think it's tacky, it's a pain to use and carry around. It is, however, fairly effective at doing what it's designed to do.

My idea is to use the new "switchable glass" for the front windshield on vehicles. Switchable glass is a glass that can be made more or less transparent at the flick of a switch. Hit the switch, the glass frosts over and ta-da! instant sun shield.

I've considered that there is a saftey issue inherent with this, but I think that it's easily solved by enabling the switch "on" position when the engine is completely turned off. An additional feature could automatically defrost the glass when the engine is started.

Bonus: Use the glass all the way around and you can turn your car into a dressing room for the beach!

Noexit, Jul 27 2005

Switchable glass http://realtytimes..../20010802_glass.htm
An introduction to switchable glass. [Noexit, Jul 27 2005]

How LCDs work (polarization) http://hyperphysics...opt/liquidc.html#c1
A quick demo of a polarized used with a watch LCD. [junglefish, Jul 27 2005]

(?) Not cheap. http://www.maybach-...aktur.com/index.htm
Goto "The Maybach", "interior", "panoramic glass roof" [AbsintheWithoutLeave, Jul 28 2005]

[link]






       I've had a quick google and can't find anything similar anywhere, and can't see why the variable tint glass couldn't be adapted for cars.   

       It would also stop any potential thieves from checking the contents of your car over.   

       [+] from me.
pooduck, Jul 27 2005
  

       I'm not clear how tinted glass would keep your car from overheating.   

       While light would no longer get through to heat the interior directly, it would instead heat up the window, which would still heat up the interior of the car. Reflective glass might make a difference, I guess.
DrCurry, Jul 27 2005
  

       It would stop the seats and various wheels and handles from reaching skin-searing temperatures wouldn't it?
pooduck, Jul 27 2005
  

       How much electricity would keeping the window clear take? If the battery ran out, you would suddenly be in a fully tinted car. Bun anyway.
dbmag9, Jul 27 2005
  

       Great idea, have it on my desk by Monday.   

       I esp. like the all-around tint idea. You could even have it happen automatically when you set the alarm as an additional safety measure. And your car insurance might give a discount for having an active security system!   

       The only problem I can see is that neglectful parents could leave their kids (or dogs) in there, and no one could tell. But at least the kids/dogs wouldn't bake to death.   

       Bun.
junglefish, Jul 27 2005
  

       One way to implement switchable glass is to have an LCD with polarizing filters on either side of the glass. The window is like a very large single pixel in a monitor.   

       Pass current and the liquid crystal rotates the polarization of incoming light, changing the way it passes through the polarization filters.   

       Such a device can be manufactured in a passive - clear or passive - opaque mode. The sunshield windshield would of course have to be manufactured as no current as transparent, and I would want a safety interlock plug to prevent it from going off during driving. Perhaps the car key could short out the window's power supply.   

       If the window uses a polarizing filter, it might no longer be possible to wear sunglasses while driving.
joeforker, Jul 27 2005
  

       joeforker, the issue with sunglasses would only occur if the windowtint were polarized to the opposite direction from driving glasses or sunglasses. The glasses are polarized vertically, so if you polarized the windows the same direction it would work. However, it might get really annoying that if you angle your head anything but perfectly upright, the effect would be progressive reduction in light transmission the more you angled your head. And who knows how your view would be affected through mirrors, turning your head to check your blind spot or back up, etc.   

       BTW, LCDs make use of polarization to work. So any LCD-based tinting would involve a polarized window. See [link].
junglefish, Jul 27 2005
  

       How about a dual layer windshield with a thin void between the two layers. When parked, the void is pumped full of mercury resulting in excellent opacity and reflectivity.
half, Jul 28 2005
  

       Also there would be a nice big mercury fountain after a car crash. It's not like mercury is poisonous or anything though... psh.
pooduck, Jul 28 2005
  

       Poisonous? Mercury? The dickens you say!
Well, so much for the perfect solution.
half, Jul 28 2005
  

       The Maybach limo has an option which is an electrochromatic sunroof.
AbsintheWithoutLeave, Jul 28 2005
  

       Since we're talking about keeping the sun out on hot days it appears obvious that solar energy is the way to go to power this sucker up.
Canuck, Jul 28 2005
  

       I've got to admit I have no idea how much it would take to power such a unit. Seems like something I read said they don't require much, but please don't hold me to that. At the same time, my current vehicle uses a not inconsiderable amount of electricity even when not running. I do like the solar powered idea.   

       DrCurry - as far as the heating is concerned, you're partly right. My current tinted windows/sun shield don't keep the interior temperature down. But, like pooduck said they do help keep the steering wheel, seats, and everything else cooler to the touch, which is half the cooling battle.
Noexit, Jul 28 2005
  

       They had something like this in CSI. Though it was bathroom doors made out of this glss.
DesertFox, Jul 28 2005
  
      
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