© Unsplash / Toan Nguyen

Glass for mobility

Feb 8, 2021

Windshields, panoramic sunroofs, sensors, touchscreens and augmented reality displays – the glass in modern vehicles isn’t simply glass but a hi-tech material: as hard as steel, with intelligent and interactive designs, a material for the mobility of tomorrow.

Glass is common in our everyday lives. We live behind glass facades, drink out of glasses, and stare at our smartphones and out of our cars through panes of glass. Historical discoveries reveal that people created the first glass objects at around 2000 B.C. Over the centuries the most varied manufacturing procedures and new uses were developed, and the evolution of glass was also important when the first automobiles were built. Early motor cars were open to the elements and did not have windows. The occupants wore goggles to protect against insects, dust and rain. At the beginning of the 20th century, the first cars appeared with windshields made of conventional glass – but available only as a special feature. The windshield of the first Model T Ford dating from 1908 looked like a round bathroom mirror. With the advent of closed car bodies, glass became one of the most important materials in vehicle construction. By the 1980s, cars had an average of about three and a half square meters of glass, but today’s models can have four and a half to six square meters. And the vehicles displayed at past motor shows and technology trade fairs demonstrate a trend toward panoramic glazing.

Multi-talented

Especially for self-driving cars, there is a demand for large areas of glass with more complex shapes offering a new feeling of space. Yet motorists don’t need to worry about safety – in an accident the composite materials used today, which are made of two layers of glass sandwiched around a thermoplastic interlayer (and legally regulated), are as safe as a steel roof. Ford has equipped a small series of its GT with the multilayer “Gorilla Glass” from Corning, which is not only thinner and up to 30 percent lighter, but should also be far more durable.  AGP eGlass develops panoramic windows measuring up to four and a half square meters. This offers a new visual experience while cutting the weight by about 35 percent compared with conventional windshields.  Researchers from the TH Mittelhessen University of Applied Sciences discovered that standard glass can be replaced with Plexiglas, which makes weight reductions of up to 50 percent a realistic possibility.

Automated defrosting with intelligent glass © Continental AG
Automated defrosting with intelligent glass © Continental AG

What used to be the preserve of a Maybach or a Bentley is now also appearing in series vehicles: windows with electrically controlled optical properties. Drivers can dim the windows while the vehicle is in motion. Various technologies are available that do this, such as suspended particle devices, polymer-dispersed liquid crystals, liquid crystals and electrochromic technology. They exploit the properties of molecules and crystals in order to regulate the optical properties of glass electrically. Electrochromic glass consists of two flat glass panes with an invisible, microscopically thin film of liquid in the middle. Electrical stimulation alters the amount of light transmitted. The voltage can be adjusted either manually or automatically.

Continental’s Intelligent Glass Control allows the user to control smart glass in the vehicle’s front, rear and side windows. So the amount of light transmitted is either regulated by pressing a button or controlled automatically – for example, the system responds dynamically to the weather conditions. Light sensors dim the glass automatically in those areas exposed to direct sunlight. This helps to stop the vehicle from heating up while parked, and greatly reduces the visibility of the interior to the outside world. Furthermore, Continental has linked its glass control to the keyless entry system. When the driver approaches the vehicle with the key or smartphone, the glass switches back to its original state.

Toyota Prius plug-in hybrid with solar roof © Toyota
Toyota Prius plug-in hybrid with solar roof © Toyota

All good things come from above

The electrical voltage for smart glass can be produced by the vehicles themselves. Audi has developed a prototype panoramic glass roof in cooperation with the Chinese photovoltaic manufacturer Hanergy. The roof contains integrated solar cells that generate energy for the on-board electrical system. In the future, the brand’s new electric vehicles should be using solar energy to power their air-conditioning and entertainment systems.  Eventually the electricity generated will also be fed directly into the traction battery to increase vehicle range. The roof of the current Toyota Prius plug-in hybrid already comes with optional photovoltaic cells from Panasonic, which have a total output of 180 W and can charge the 8.8 kWh lithium-ion battery.  If the car is parked in the sun, the solar cells in the glass roof can charge the battery several times a day. While the vehicle is in motion, the system also charges the 12 V battery and again raises the efficiency of the hybrid system. Sufficient energy is generated for an annual mileage of approx. 1,000 kilometers. With unimagined consequences: millions of cars will mutate into small power plants to enhance their own electrical propulsion and maybe also soon to deliver excess energy to the smart grid.

Glass for sensor technology

Glass is also important under the hood. It helps regulate the injection pump, check the tire pressure, and trigger the ABS and the airbag at the right time. The sensor technology in these systems uses glass. And special glass in LiDAR sensors will improve safety in the autonomous cars of tomorrow. Thanks to its properties, glass is also predestined for antenna systems linking the connected car to its environment.  Moreover, new lighting concepts are also emerging that are based on multitasking glass. For instance, LED, matrix LED and laser headlamps need glass to handle the production of heat and guarantee their range. In addition, glass surfaces have visible functions as an interface for digital applications. For example, holographic optical projection surfaces made of glass enable the latest head-up displays to project information in 3-D directly into the driver’s field of vision. The company Corning  is turning cars into futuristic cockpits. Instead of dials, levers and switches, the interior is equipped with three-dimensional glass surfaces with interactive touchscreens and novel projection surfaces. This means that gradually glass will fundamentally revolutionize the way we communicate with the world around us.

The IAA 2021 will focus on innovative mobility in all its forms. Intelligent traffic solutions, visionary mindsets, automobiles and entire mobility chains. Everything that will shape the mobility of tomorrow and make it an experience. Be there!