Smart glass, also known as electrochromic glass and switchable glass has been around for several years at this point. Along with the pursuit of the ‘smart’ home, it is becoming an increasingly popular choice for offices and homes alike, not only for its aesthetic qualities but also for its energy saving abilities.
How Does it Work?
There are a number of different types of smart glass, each with different properties, some simply darken in bright light similar to the transition lenses offered in eyeglasses, some become translucent whilst others become opaque and mirror-like. The effects of each of these types of glass are produced when voltage, light or heat are applied.
Electrochromic glass changes its properties in response to voltage which allows control over the amount of light and heat that can pass through. Electrochromic windows change their opacity between transparent and tinted. A voltage is required for changing the opacity but not needed for maintaining the achieved level. Modern-day electrochromic panes can achieve this tint in under three minutes whereas earlier versions could take anywhere up to 30 minutes depending on the size of the glass.
Electrochromic glass cannot achieve an opaque state, maintaining visibility even when tinted. Common small-scale applications include rear-view mirrors, protection of artefacts underneath glass in museums.
The glass can be programmed to change state automatically depending on variables such as the suns position or the weather and can also be controlled by smartphone applications and by ‘smart’ home assistants making this option very use-able in an office setting to reduce glare on screens and regulate temperatures whilst reducing energy costs.
Polymer Dispersed Liquid Crystal
A liquid mix of polymer and crystals is placed between to layers of glass along with a thin layer of a transparent conductive material forming a sandwich which for all intents and purposes is a capacitor.
With no voltage applied to the glass, the liquid crystals are scattered randomly throughout the pane which scatters light as it passes through giving the glass a translucent cloudy white or smoke appearance. When a voltage is applied an electric field is formed between the two electrodes on the glass which causes the liquid crystals to align allowing light to pass through cleanly and making the glass transparent. The amount of transparency is controlled by the amount of voltage that is applied.
Other technologies are constantly in development such as Micro-blinds which are under development at the National Research Council in Canada. The panes feature tiny rolled metal blinds that are virtually invisible to the human eye. With no electricity applied the blinds remain rolled up and allow light to pass through. When a voltage is applied allow the metal blinds to stretch and block the light. One of the key advantages of this technology is the speed it takes to change is a matter of milliseconds along with the fact they are much cheaper to fabricate.
These are just a couple of the types of ‘smart glass’ there are others which work in different ways such as nanocrystal, photochromic, thermochromic and suspended particle glass. Maybe there will be a part 2 to this blog to look into those. What we have established so far though is that ‘smart’ glass seemingly deserves its name as it brings with it numerous benefits such as on-demand privacy, control of light, temperature and glare and more efficient control over energy consumption ultimately reducing costs.
By Andrew Mairs - Marketing Executive