See-through displays and 'smart' windows soon

Scientists have developed transparent light shutters that may soon pave the way for see-through displays and "smart" windows.

The novel liquid crystal technology allows displays to flip between transparent and opaque states -- hypothetically letting you switch your view in less than a millisecond from urban decay to the beautiful river across the street.

The idea of transparent displays has been around for a few years, but actually creating them from conventional organic light-emitting diodes has proven difficult.

"The transparent part is continuously open to the background. As a result, they exhibit poor visibility," said Tae-Hoon Yoon, primary investigator from the Pusan National University in South Korea.

Light shutters, which use liquid crystals that can be switched between transparent and opaque states by scattering or absorbing the incident light, are one proposed solution to these obstacles, but they come with their own set of problems.

Yoon's group's new design remedies these problems by using scattering and absorption simultaneously.

To do this, Yoon's group fabricated polymer-networked liquid crystals cells doped with dichroic dyes used in the LCD industry.

In their design, the polymer network structure scatters incident, or oncoming light, which is then absorbed by the dichroic dyes.

The light shutters use a parallel pattern of electrodes located above and below the vertically aligned liquid crystals.

"The incident light is absorbed, but we can still see through the background with reduced light intensity," Yoon noted.

Yoon's group is working on to increase and decrease the device's transmittance at the transparent and opaque states, as well as developing a bi-stable light shutter which consumes power only when states are being switched.

The work appeared in the journal AIP Advances.