A Guide on Switchable Smart Glass

Switchable glass comes by many names, ranging from PDLC glass to switchable smart glass, electrochromic glass and similar terms that are used to refer to smart films that contain micron-size liquid crystal droplets dispersed in a polymer matrix with optical isotropic properties. With the help of the right combinations of polymer and liquid crystal materials, PDLC films can be made to switch from light-scattering, opaque off-state to non-light-scattering, transparent on-state and vice versa, using an electrical charge. In its off-state, the film appears an opaque milky white because of a refractive index mismatch produced by the disordered liquid crystal molecules within the PDLC interface.

As an electrical field becomes charged and electricity is applied across the switchable glass film, the molecules within the liquid crystal micro-droplets align so that higher relative permittivity is produced and aligned parallel to the direction of the electric field. As a result, the on-state produces a refractive index that is sufficiently close between the droplets in the polymer matrix and the polymer matrix material, making the film appear transparent.

Switchable smart glass has a wide range of applications, ranging from switchable windows, and other such devices that require variable transparency on command. Electrical charge is enabled by the final PET film coating that goes on top of liquid crystal layer so that the film structure can be enclosed by an electrically conductive material (usually Indium Tin Oxide or ITO).

The layers of ITO contains a mixture of tin oxide and indium oxide, which produces high electricalconductivity. Thin layers of these materials provide sufficient transparency in the area of visible light, making them ideal for use in PDLC glass structures as they don’t interfere with the transparency that the electrically charged liquid crystals produce once the film is in the light-passing on-state.

By admin | May 7, 2020 | Uncategorized

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