In the automotive industry use of smartfilm has been very limited up until now. One of the reasons for this is that smartfilms cannot be used in spherically bended glasses without wrinkles in the foil.
Car manufacturers can change the shape of a glass to a more flattened surface, this however is not ideal as designers want to have freedom to use shapes.
There are different types of active interlayer that can be laminated in between two sheets of (curved) glass. Like SPD, PDLC, electro-chrome. All are build-up from 2 conductive coated PET layers, bonded with liquid crystals. If an electric current flows through the crystals it causes the film to switch in color or transparancy.
DK has developed a system to shape this type of interlayer before laminating. Our unique method is currently patent pending, but working prototypes have already been made.
The prototypes we made have a double curvature, with a strong bend and cross-bend. We are also working on methods to use this shaping in serial circumstances.
This is a visualisation of the areas of compression and decompression. In red and yellow compression, where wrinkles will occur without pre-forming.