Windshield

The windshield (North America) or windscreen (EU & Commonwealth countries) of an aircraft, car, bus, motorbike or tram is the front window. Modern windshields are generally made of laminated safety glass, a type of treated glass, which consists of two (typically) curved sheets of glass with a plastic layer laminated between them for safety, and are bonded into the window frame. Motorbike windshields are often made of high-impact acrylic plastic.

Windshields protect the vehicle's occupants from wind and flying debris such as dust, insects, and rocks, and provide an aerodynamically formed window towards the front. UV coating may be applied to screen out harmful ultraviolet radiation. However, this is usually unnecessary since most auto windshields are made from laminated safety glass. The majority of UV-B is absorbed by the glass itself, and any remaining UV-B together with most of the UV-A is absorbed by the PVB bonding layer.

On motorbikes their main function is to shield the rider from wind, though not as completely as in a car, whereas on sports and racing motorcycles the main function is reducing drag when the rider assumes the optimal aerodynamic configuration with his or her body in unison with the machine, and does not shield the rider from wind when sitting upright.

Early windshields were made of ordinary window glass, but that could lead to serious injuries in the event of a crash. A series of crashes led up to the development of stronger windshields. The most notable example of this is the Pane vs. Ford case of 1917 that decided against Pane in that he was only injured through reckless driving. They were replaced with windshields made of toughened glass and were fitted in the frame using a rubber or neoprene seal. The hardened glass shattered into many mostly harmless fragments when the windshield broke. These windshields, hovever, could shatter from a simple stone chip. In 1919, Henry Ford solved the problem of flying debris by using the new French technology of glass laminating. Windshields made using this process were two layers of glass with a cellulose inner layer. This inner layer held the glass together when it fractured. Between 1919 and 1929, Ford ordered the use of laminated glass on all of his vehicles.

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