If your car has a sunroof, you’ve undoubtedly pulled the screen over it for some shade on a sunny day.
Now a new glass roof from Mercedes-Benz, called Magic Sky Control, achieves the same goal without a screen, going dark at the touch of a button to keep the sun from shining in.
It’s available as an option on the 2012 retractable-roof SLK roadster.
“The technology differs from both auto-dimming mirrors and in eyeglasses that automatically go dark, using a different kind of sensor technology,” says David Sherrard, SLK product manager for Mercedes-Benz Canada.
“Unlike those photogrey (eyeglass) lenses, Magic Sky Control system relies on electricity to vary the opacity of the glass.”
The sunroof can be either left transparent, or darkened by pushing a button.
The system uses a control unit and converter that are integrated into the front section of the roof.
When these send an electrical voltage through the glass, particles within the glass position themselves so that light can pass through — the window is transparent.
However, once the voltage is turned off, the particles position themselves randomly, which partially blocks the light and turns the glass dark.
Even in transparent mode, the roof blocks UV and infrared light, Sherrard says, but insulation increases significantly and noticeably when the glass is darker.
This helps to keep the temperature on interior parts such as armrests cooler by up to 10 degrees Celsius compared with conventional green glass or a sunshade, Sherrard says.
Because it depends on electrical current to stay transparent, the glass goes dark when the car is shut off and power no longer goes to the roof system. This keeps the car from getting too hot when it’s parked in the sun, which in turn reduces the amount of air conditioning needed when it’s started up again.
The automaker tested the roof in 50C heat in Death Valley, where the load from the sun dropped by one-twentieth when the Magic Sky Control roof went from transparent to dark.