The Suspended Particle Device is a film that turns vehicles’ sunroofs and other glass from transparent to opaque, blocking the infrared and ultraviolet light that heat interiors and prematurely age leather and other interior material. The feature began as a US$2,500 option on luxury convertibles and is now coming to mass-market vehicles.
“You can control the amount of heat and glare coming into the cabin,” said Joe Harary, CEO of Research Frontiers, the US nanotechnology research firm that developed the film.
A small electric current runs through the film, which makes microscopic particles move into lines, creating a window shade that blocks up to 99.5% of light. When the current stops, the particles flip back to their unaligned positions, making the glass transparent again. The film attaches to the inside of a sunroof or window.
The film can boost fuel economy or electric range of a car, as less energy is used to run air-conditioning when the car is in direct sunlight, and compressors can be made smaller.