Today we touch the touchscreen of our smartphone many times a day – far too many – with gestures that seem obvious, almost innate. Yet behind every tap, every swipe, every “pinch” to resize a photo or a web page, lies a long and surprising history, which has its roots in the middle of the last century. Before becoming the universal interface of mobile devices, the touchscreen went through over sixty years of attempts, intuitions and false starts, oscillating between very different engineering approaches.
It all began with the first experiments linked to television broadcasts in the 1940s and with the optical systems of the 1960s, and then divided into two large technological families: the capacitive one, which reacts to the electrical conductivity of the human body, and the resistive one, based on physical pressure. For decades the touch remained confined to industrial, military, aeronautical and academic uses, until it found the first real test bed for mass diffusion in the mobile phones of the 90s, and was definitively established with the arrival of multi-touch in the early 2000s. Let’s retrace together the journey that the touchscreen took to reach us.
The origins: from cathode ray tubes to the invention of the touch screen in 1965
It all began in 1946, when the Philco Company filed a patent for a particular direct light pen, designed for sports broadcasts on TV. Resting on a cathode ray tube screen (the old and bulky monitors, you know?) this pen amplified the signal, allowing temporary circles and arrows to be drawn on live images: an ancestor, in some ways, of modern interactive commentary graphics.
We will have to wait until the 1960s for the next leap. In 1962 the AT&T company patented an optical system independent of the screen light, based on a matrix of crossed light rays and photodetectors: when a finger or an object interrupts the ray, the system identifies its position. A year later, in 1963, Robert E. Graham perfected the idea with the indirect light pen, which allowed you to draw on a separate surface while seeing the line reproduced on the computer.
However, 1965 marked an important turning point: in England, Eric Johnson laid the foundations of the first touchscreen that could be operated directly with the fingers, laying the foundations of the capacitive screen. The principle is as simple as it is ingenious: an insulating material, such as glass, is covered with a transparent conductive material; when the finger – an excellent electrical conductor – touches the surface, it alters the capacitive field and the system records the contact in a binary way, thus limiting itself to detecting the presence or absence of the touch. At the same time, in Germany, the team led by Rainer Mallebrein worked on an ultrasonic system for air traffic control, which in 1970 transformed into a glass screen with a conductive coating.
In the 70s touch began to multiply in different directions. On the one hand, the infrared optical touchscreen was born, adopted in 1972 by the PLATO IV student terminal at the University of Illinois, which uses a grid of LEDs and phototransistors to detect light interruptions. On the other hand, almost by chance, resistive technology was born: G. Samuel Hurst and his team, at the University of Kentucky, were looking for a faster way to read Cartesian coordinates in atomic physics calculations and began experimenting with electrically conductive paper. The intuition, refined in the basement of the house where Hurst founded Elographics, leads to the superposition of two conductive sheets spaced apart: the pressure of the finger brings them into contact, causing the voltage between the two layers to vary and allowing the exact position of the point touched by the user to be calculated. Economical and robust, this technology soon becomes a point of reference in factories and hospitals.
Also in these years, at CERN, engineers Frank Beck and Bent Stumpe developed a transparent capacitive screen, in use since 1973, theoretically already capable of managing multi-touch, i.e. the simultaneous touch of multiple fingers, even if this function was deactivated via software because it was considered useless for the time.
The 80s: the decade of experiments
In 1982, within the laboratories of the University of Toronto, researcher Nimish Mehta designed the pioneering system that allowed a human being to interact using multiple fingers simultaneously. Rather than a real touch-sensitive screen, it was a graphics tablet or touch tablet. The engineering team at the Input Research Group discovered that by placing a video camera beneath a sheet of opaque glass they could track movements; the system, in fact, decoded the visual inputs by capturing the shadow areas or “dark points” imprinted on the surface during contact. This invention was considered so revolutionary by Bill Buxton, a key figure in the evolution of multi-touch systems, that he pushed him to include it as a milestone in his famous historical reconstruction dedicated to digital input systems.
Touch then began to appear outside the laboratories too: it was tested on the dashboards of airplanes and even cars, as demonstrated by the Electronic Control Center introduced by General Motors in 1985 on the Buick Riviera. The experiment, however, turns out to be a bit of a fiasco, thanks to customers’ distrust towards a technology perceived as too new and high repair costs.
Towards the end of the decade came a crucial turning point in terms of usability: researchers at the University of Maryland developed the so-called “take-off strategy”, which solved the precision problems that plagued that technology. Thanks to their idea, the action on the screen is activated only when the user’s finger is lifted, finally allowing even a single pixel to be precisely selected.
From the 90s to today: touch on the first mobile phones
In the 90s, touch entered the consumer world. In 1993, IBM presented, in collaboration with BellSouth, the famous IBM Simon, the first touchscreen mobile phone in history, equipped with a resistive screen and stylus. Shortly after, Newton arrives, Apple’s personal digital assistant, which turns out to be one of the biggest flops ever for the Cupertino giant. The user experience, in fact, was cumbersome, the interface was still designed to be used with a precise pointer, with small drop-down menus not suitable for interactions with human fingers.
The real revolution exploded in the early 2000s. On the entertainment front, in 2004 Nintendo released touch to the general public with the Nintendo DS portable console, demonstrating that touching a screen can be a natural and immediate way of interacting with a device. In the same period, Apple begins to file the first patents for an advanced capacitive touchscreen designed for mobile devices: the goal is no longer just to detect a touch, but to interpret a complex sequence of simultaneous impulses.
Even before Apple’s debut, however, another giant wrote a page of history: in May 2007 the LG Prada was presented, the first mobile phone on the market equipped with a modern capacitive screen, capable of responding instantly to simple skin contact, without the need for pressure or a stylus. A month later, in June 2007, the arrival of the first iPhone changed the rules of the game forever: it wasn’t just a matter of adopting capacitive technology, but of building an entire operating system around it designed for touch and multi-finger gestures. Inertial scrolling, that fluid movement of pages that continues for a few moments before stopping, and the famous pinch-to-zoom (the “pinch” gesture made with two fingers on the screen to zoom on photos and web pages) soon become part of our everyday life, made possible thanks to the screen’s ability to detect multiple points of contact simultaneously.
The result? In just two years, by the end of 2009, phones with touch displays outnumbered non-touch ones for the first time, kickstarting an unprecedented commercial boom and transforming the touchscreen into the global standard we still hold in our hands today.
