Smart glass

Video to document the functionality

As intelligent glass ( English Smart Glass ) are tintable glazing referred whose light transmittance by applying an electrical voltage ( electrochromism ), changing light conditions ( photochromism ) or heat ( thermochromism changed). Various technologies and fields of application are summarized under the generic term intelligent glass . Depending on the design, these glasses can serve as sun protection (glass remains transparent) or act as a privacy screen (glass becomes opaque ).

Electrochromic glass

Sun visor on an airplane window simulated by electrochromic glass

Structure and functionality

Electrochromic glass uses the property of electrochromic materials to change the light transmission depending on the applied DC voltage . By applying a low voltage of 3-5 volts, a bluish color is achieved. When electrical charges are transferred to a microscopically thin coating ( e.g. tungsten trioxide , polyaniline ), it becomes optically active and changes its color. This process can take anywhere from a few seconds to several minutes. If the polarity of the voltage is changed, the glass becomes transparent again. The glass only needs a current of approx. 2 amps during the coloring phase or when creating complete transparency. If no voltage is applied, the glass retains its current color.

Depending on the application, the voltage can be regulated manually or automatically, for example by sensors that measure the brightness.

Application examples

In vehicle construction as a roof window, for example in the Ferrari 575 M Superamerica
Rearview mirrors dimming automatically or at the push of a button

Building glazing for temperature regulation or as UV protection

Thermochromic glass

Structure and functionality

Thermochromic glass uses the property of thermochromic materials to change their light absorption depending on the temperature. When exposed to sunlight, the thermochromic glasses heat up and become colored. If the sunlight subsides, the thermochromic glasses cool down again and discolor. Thermochromic glasses are usually designed as laminated glasses , ie two panes of glass are laminated together with a special film. This film contains the thermochromic substances.

Application examples

As switchable thermochromic sun protection glass

LC glass

LC glass or PDLC glass for liquid crystal or polymer dispersed liquid crystal becomes transparent when an electrical voltage is applied and functions similarly to an LCD . This process is reversible .

Structure and functionality

Lounge with a clear view of the driver's cab

Opaque glass wall

LC-glasses are based on a polymer - liquid crystal film which is embedded between two flat glass panes and is connected to a voltage source. The randomly oriented liquid crystal molecules are located within the solid polymer. The incident light is scattered by them and the pane is opaque , so it looks like frosted glass.

When an electrical voltage is applied, the liquid crystal molecules arrange themselves in the electrical field - the glass becomes transparent to the eye. At an oblique viewing angle, the effect causes a slight clouding for the viewer.

When the voltage is removed, the liquid crystal molecules are disordered again and the pane becomes opaque again and thus almost completely opaque. These glasses are primarily suitable as privacy protection, but not as sun protection.

costs

The price is between 1700 and 2000 € / m² including installation.

Application examples

Partition wall systems for open plan offices
The lounge in ICE 3 and ICE T trains is separated from the driver's cab by LC glass .
Options for the Maybach 57, 62 and Landaulet
The side windows of the gondola lift of the Bukit Panjang LRT are made of LC glass and become opaque when they drive very close to residential buildings.