According to PC Magazine, a touch screen is, "a display screen that is sensitive to the touch of a finger or stylus. Widely used on ATM machines, retail point-of-sale terminals, car navigation systems, medical monitors and industrial control panels, the touch screen became wildly popular on handhelds after Apple introduced the iPhone in 2007."

The touch screen is one of the easiest to use and most intuitive of all computer interfaces, a touch screen allows users to navigate a computer system by touching icons or links on the screen.

How Touch Screen Technology Works

There are three components used in touch screen technology:

The touch sensor is a panel with a touch responsive surface. Systems are built based on different types of sensors: resistive (most common), surface acoustic wave, and capacitive (most smartphones). However, in general, sensors have an electrical current running through them and touching the screen causes a voltage change. The voltage change signals the location of the touching.

The controller is the hardware that converts the voltage changes on the sensor into signals the computer or another device can receive.

Software tells the computer, smartphone, game device, etc, what's happening on the sensor and the information coming from the controller. Who's touching what where; and allows the computer or smartphone to react accordingly.

Of course, the technology works in combination with a computer, smartphone, or another type of device.

Resistive and Capacitive Explained

According to Malik Sharrieff, an eHow Contributor, "the resistive system is comprised of five components, including the CRT (cathode ray tube) or screen base, the glass panel, the resistive coating, a separator dot, a conductive cover sheet and a durable top coating."

When a finger or stylus presses down on the top surface, the two metallic layers become connected (they touch), the surface acts as a pair of voltage dividers with connected outputs. This causes a change in the electrical current. The pressure from your finger causes conductive and resistive layers of circuitry to touch each other, changing the circuits' resistance, which registers as a touch screen event that is sent to the computer controller for processing.

Capacitive touch screens use a layer of capacitive material to hold an electrical charge; touching the screen changes the amount of charge at a specific point of contact.

History of Touch Screen Technology

1960s

Historians consider the first touch screen to be a capacitive touch screen invented by E.A. Johnson at the Royal Radar Establishment, Malvern, UK, around 1965 - 1967. The inventor published a full description of touch screen technology for air traffic control in an article published in 1968.

1970s

In 1971, a "touch sensor" was developed by Doctor Sam Hurst (founder of Elographics) while he was an instructor at the University of Kentucky. This sensor called the "Elograph" was patented by The University of Kentucky Research Foundation. The "Elograph" was not transparent like modern touch screens, however, it was a significant milestone in touch screen technology. The Elograph was selected by Industrial Research as one of the 100 Most Significant New Technical Products of the Year 1973.

In 1974, the first true touch screen incorporating a transparent surface came on the scene developed by Sam Hurst and Elographics. In 1977, Elographics developed and patented a resistive touch screen technology, the most popular touch screen technology in use today.

In 1977, Siemens Corporation financed an effort by Elographics to produce the first curved glass touch sensor interface, which became the first device to have the name "touch screen" attached to it. On February 24, 1994, the company officially changed its name from Elographics to Elo TouchSystems.

Elographics Patents

US3662105: Electrical Sensor Of Plane Coordinates

Inventor(s)Hurst; George S., Lexington, KY - Parks; James E., Lexington, KY

Issued/Filed Dates:May 9, 1972 / May 21, 1970

Inventor(s)Hurst; George S., Lexington, KY - Parks; James E., Lexington, KY Issued/Filed Dates:May 9, 1972 / May 21, 1970 US3798370: Electrographic Sensor For Determining Planar Coordinates

Inventor(s)Hurst; George S., Oak Ridge, TN

Issued/Filed Dates:March 19, 1974 / April 17, 1972

1980s

In 1983, the computer manufacturing company, Hewlett-Packard introduced the HP-150, a home computer with touch screen technology. The HP-150 had a built-in a grid of infrared beams across the front of the monitor which detected finger movements. However, the infrared sensors would collect dust and require frequent cleanings.

1990s

The nineties introduced smartphones and handhelds with touch screen technology. In 1993, Apple released the Newton PDA, equipped with handwriting recognition; and IBM released the first smartphone called Simon, which featured a calendar, notepad, and fax function, and a touch screen interface that allowed users to dial phone numbers. In 1996, Palm entered the PDA market and advanced touch screen technology with its Pilot series.

2000s

In 2002, Microsoft introduced the Windows XP Tablet edition and started its entry into touch technology. However, you could say that the increase in the popularity of touch screen smart phones defined the 2000s. In 2007, Apple introduced the king of smartphones, the iPhone, with nothing but touch screen technology.