“Switchable” glass and light
In a world that demands products that are energy-efficient as well as offering privacy and security, switchable glass has emerged. This new technology uses an electrical charge to control the amount of light passing through glass. It provides the ability to instantly and precisely control the clarity of the glass, and to easily adjust light transmission manually with a dimmer switch or automatically using a photocell.
It works like this: microscopic light-absorbing particles are dispersed within a thin film that is placed between two pieces of glass. When no electrical charge is applied to the film, these particles absorb light, darkening the glass (see diagram below).
However, when an electrical charge is applied, the particles align and allow light to pass through. By simply adjusting the electrical voltage, light passing through the film can be controlled.
Developed by Research Frontiers, the thin, flexible Suspended Particle Device (SPD) film can be used in a variety of applications including windows, interior partitions, and skylights, in new or retrofit construction.
Currently, three manufacturers in the building industry are licensed in this technology: Razor’s Edge, Lewis, Del.; SPD Systems, Plantation, Fla.; and Thermoview, Louisville, Ky. The “smart” windows are controlled using AC voltage or battery power.
The film operates over a wide temperature range and can be bent or rolled. For more information: www.refr-spd.com
(Mindi Zissman, Products Editor)