At the turn of the 21st century, touch screen technology began to make serious headway into both industrial processes and the lives of the population. The first digital signage display monitors were produced in 2001 and allowed users to access and manipulate information quite literally at the touch of a finger. The technology is firmly rooted in the graphic design industry and all its applications and of course, the price tag would have made even the most-ardent technophile blush. These initial devices would have cost up to $40,000 (£23,000), to install, set up and connect to the necessarily more powerful servers.
By 2002, the first large flat screens which could recognise many positions and touch points simultaneously were manufactured. They employed capacitive sensing techniques, and they worked by calculating the distance between the surface and the finger interacting with the interface (the screen). A significant advantage of these devices is that the display elements are all fully integrated onto the screen and so do not need a camera to detect movement. This means that they will not cease to operate in poor lighting and lend themselves to be used as sunlight readable screens. The prime reasoning for the development of flat screens was to facilitate the transformation of a device such as a TV screen into a fully interactive application by integrating them with external hardware such as a PC / Mac or gaming console. Such developments allowed several users to interact with the screen and its applications with no interference with each other. At this time, such multi-touch technology was still in its infancy but was on the cusp of entering the mainstream. Again a key stumbling block was the cost of the technology these early devices could cost several thousand dollars apiece.
Frustrated Total internal Reflection (FTIR)
When light travels between different elements; for instance air and glass, the light ray will slow down because the glass is denser than the air. All substances, however, have what is called a critical angle; this is the point at which the light waves will be reflected back into the glass, at this point total internal reflection has occurred. Fingerprint imaging technology works by shining light through Plexiglas or an equivalent material to gain a detailed image of a fingerprint. In 2006, this technique was applied to touch screen technology. Infra-red light is made to reflect back and forth within the top and bottom layers of the material. When a finger touches the surface (through which the light is travelling) the beam is scattered around the contours of the fingerprint. In touch screen technology, the method is adapted so that the touch is picked up by an infrared camera and the point of contact given a coordinate. Clearly, each coordinate has an icon or tab which is assigned a particular function such that the action can be carried out by the computer.
Developments such as FTIR are one of the many that occurred in the early 2000’s which collectively catalysed the influx of touch screen technology to mainstream consumer markets. The devices that are in use today have their roots in the application of existing and new-technological innovations.