SPD Glass

SPD smart window is constructed by using two panes of glass separated by a conductive film with suspended, light absorbing, microscopic particles. Microscopic light-absorbing particles are dispersed within a thin film. When no electrical voltage is applied to the film, these particles absorb light, making the glass dark. When voltage is applied, the particles align and allow light to pass through. By simply adjusting the electrical voltage manually or automatically, the amount of light passing through the SPD-glass product can be controlled quickly and precisely. While this type of smart window is capable of changing at the turn of a button, one disadvantage is that electricity is required to keep the window transparent. However, there are some advantages of this type of smart window over the other two types. Electrochromic glass responds slowly, has limited cycle lifetime, and has an “iris effect” where color change begins at the outer edges of the window and trickles its way toward the center. Liquid-crystal glass is either clear or opaque with no in-between states, and merely scatters light rather than blocking it, which limits it to certain interior privacy applications.

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