The solution to sun glare, long a problem in the cabin, has in the past meant pulling the shades to block out the light. Now, Research Frontiers, of Woodbury Park, N.Y., is offering improved suspended particle device (SPD) light-control technology as a new solution that allows the passenger visual access to what’s outside without the glare.

The company calls it the SPD-Smart window. It has no moving parts and is rheostat controlled, allowing the passenger to choose how much light passes through the window.

The principle of the SPD is relatively simple. In an SPD window, millions of SPDs are placed between two panels of glass or plastic coated with a transparent conductive material. When electricity comes into contact with the SPDs via the conductive coating, they line up in a straight line and light is allowed to pass through.

When the electric current is removed, the particles move back into a random pattern and block light. The amount of light passing through can be changed by using a rheostat to control the amount of electrical current.

According to Research Frontiers, the system saves weight by eliminating the
need for electric or manually operated window shades.