Smart Windows are windows which use a glazing
material to control the amount of light that is allowed
to pass through the glass panes.
The glazing material is often called “switchable
These materials change their optical behaviour with
application of electrical voltage.
Electrochromic windows centred around special
materials that have electrochromic properties .
‘Electrochromic’ describes materials that can
change color when energized by an electrical
Electrochromic windows darken when voltage is
added and are transparent when voltage is taken
The basic working principle involves lithium ions
(positively charged lithium atoms—with missing
electrons) that migrate back and forth between the
two electrodes through the separator.
When the glass is clear, the lithium ions reside in the
When a small voltage is applied to the electrodes,
the ions migrate through the separator to the
outermost electrode , where they scatter away most
of the incoming light and turn the glass opaque.
They remain there all by themselves until the
voltage is reversed, causing them to move back so
the glass turns transparent once again.
SPD window consists of several layers:
Two panels of glass or plastic.
Conductive material - used to coat the panes of
Suspended particle devices - millions of these black
particles are placed between the two panes of glass.
Liquid suspension or film - allows the particles to
float freely between the glass.
Control device - automatic or manual.
In suspended particle devices (SPD), a thin film
laminate of rod-like particles suspended in a fluid is
placed between two glass or plastic layers, or
attached to one layer.
When the power supply is switched on, the rod
shaped suspended particle molecules align, light
passes through and the SPD Smart Glass panel
When the power supply is switched off the rod
shaped suspended particle molecules are randomly
oriented blocking light and the glass panel looks
The SPD Smart Glass when becomes dark can
blocking up to 99.4% of light. SPD Smart Glass
protect from damaging UV when on or off.
Polymer dispersed liquid crystal is simply micro
droplets of liquid crystals encapsulated in a polymer.
The liquid mix of polymer and liquid crystals is
placed between two layers of glass that includes a
thin layer of a transparent, conductive material.
With no applied voltage, the liquid crystal
molecules remain in a randomized configuration
that refracts the light that enters the mixture,
making it appear opaque.
This results in the translucent,
"milky white" appearance.
When a voltage is applied to the electrodes, the
electric field formed between the two transparent
electrodes on the glass.
The molecules line up the direction of the electric
field, allowing light to pass through what is now
essentially a transparent surface.
The degree of transparency can be controlled by the
control of light.
Ambient temperature control.
Protecting skin from damaging UV rays.
Low working voltage.
Long life – tested to in excess of 100,000 cycles.
Building, hotels and offices