Smart glass: where aesthetics, discretion, and security converge

Although the first experimental implementations of smart glass date back to the 1960s, its mass commercial use began a few decades later. Due to its multiple applications in different verticals, this technology is attracting more attention today

By: Nermin Kabahija; E-mail: redakcija@asadria.com

Smart glass is also known as intelligent or electrochromic glass. It is a special type of glass that can change its transparency, i.e. its appearance, when combined with electricity. It consists of layers of special materials and conductive coatings between two layers of glass or plastic material. When brought into contact with an electric current, the materials react and change their structure, which leads to a change in the levels of transparency of the glass. This means that it can switch between transparent and opaque states as needed, making it highly appropriate for many industries.

Modest beginnings

Early installations of smart glass were mostly limited to individual windows or smaller areas, rather than facades or large glass surfaces. The first mass installation in buildings began in the mid-2000s, although smart glass technology was developed much earlier, dating back to 1960. However, its application in real-life projects was limited due to high production costs and numerous technical challenges. Technological progress, reduction of production costs, and increasing awareness of energy efficiency have encouraged the wider application of smart glass in buildings. This included installation in office buildings, hotels, shopping malls, and some luxury residential buildings. Later, the technology spread to different types of facilities, including residential buildings, hospitals, schools, museums, and sports halls.

How does it work?

Active smart glass is based on several similar technologies: PDLC, SPD, and electrochromic technology. Polymer-dispersed liquid crystals (PDLC) are used to control light transmission through transparent materials such as glass or polycarbonates. Glass consists of layers of liquid crystals between two layers of transparent electrodes. The liquid crystals in the PDLC material are normally found in a state of disorder, which allows light to pass freely through the material. When an electric field is applied across the electrodes, the liquid crystals are re-oriented and re-arranged, leading to the diffraction of light and the ensuing opacity of the material. By turning off the voltage, the liquid crystals return to their disordered state and the material becomes transparent. PDLC is one of the most widely used technologies. Although this type of film is generally used for indoor uses, it can be optimized to maintain its properties in outdoor areas and is available in all colors and patterns. When opaque, PDLC is ideal for privacy protection, projections, and whiteboard use. Given that it blocks visible light, glass with PDLC foil reflects both solar radiation and infrared light, thus cooling the interior.

Microscopic particles

SPD (Suspended Particle Device) materials use particle suspension technology that responds to electrical voltage to control the transparency of the material. The technology consists of two layers of transparent electrodes, between which there is a suspension of microscopic particles that retain their natural color and can be polarized under the influence of an electric field. When the electrical voltage is turned on, the particles align in straight lines and thus contribute to the diffraction of light, and the material becomes opaque. This process of changing light transmittance unfolds quickly and without visible transition states, which is one of the advantages of SPD over other types of technologies. SPD materials are often used in windows and other surfaces to regulate the amount of light and heat that passes through the material.

Applications

Smart glass offers several advantages: energy efficiency, privacy protection, lighting regulation, and aesthetics. The application of smart glass is diverse. First, it can be used in building windows to control the amount of sunlight and heat entering the room. It is also used in glass partitions, on shower cabin doors, mirrors, and other surfaces which you want to control privacy or reduce lighting with. In the construction industry, it is used in windows, facades, and building partitions to control the flow of light and heat, thereby improving energy efficiency and reducing cooling and heating costs. In the automotive industry, it is used to make electrochromic mirrors or sunroofs, while in the medical sector, smart glass is applied to operating room windows to provide privacy and reduce noise. It is also used in imaging devices such as X-rays or ultrasounds, where the passage of light can be controlled or visibility changed. Recently, it has been increasingly used in electronic devices such as smartphones and tablets to create additional screens that can be folded or become transparent when inactive.

Security industry and smart glass

Smart glass provides several benefits in the security industry as well. It can be used as a security layer on windows or glass doors to increase resistance to burglary. When the glass is in an opaque state, it prevents visibility of the interior of the room, making it difficult for potential burglars to plan their actions. It can also be integrated into access control systems. By combining smart glass with biometric sensors or other identification systems, ensuring selective access to the premises is made easier. The glass can become transparent only to authorized persons while keeping others out of sight. Combined with video surveillance, it can ensure discretion and privacy by being transparent to security personnel or surveillance cameras, allowing them to monitor the situation, while appearing opaque to passers-by or visitors.

Smart glass can be used in emergencies such as earthquakes or terrorist attacks. When an appropriate alarm system is activated, smart glass can become opaque to protect people from harmful effects, providing cover and reducing visibility for potential intruders. On top of all that, smart glass can also communicate various messages within the alarm system. In general, smart glass in the security industry allows for adaptability, discretion, and an additional level of protection, contributing to the overall feeling of security and improving measures aimed at achieving it.

Manufacturers

There are multiple manufacturers of smart glass around the world. The French company Saint-Gobain is one of the world’s leading manufacturers of building materials, including smart glass. Their smart glass product line is called SageGlass and offers different variants of smart glass for controlling light and heat in buildings. The next manufacturer is Samsung Electro-Mechanics as the largest Asian manufacturer, while Research Frontiers and View have a strong presence in the Northern American Market. Chinese companies such as Beijing All Brilliant Technology and Smart Glass International are also actively involved in the production of smart glass.