A special thanks goes to Jason Ford of Elo TouchSystems, the company whose founder invented touch screen technology, for providing the following historical information.

In 1971, the first "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.

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 five-wire resistive technology, the most popular touch screen technology in use today. On February 24, 1994, the company officially changed its name from Elographics to Elo TouchSystems.

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

US3798370: Electrographic Sensor For Determining Planar Coordinates
Inventor(s)
Hurst; George S. , Oak Ridge, TN
Issued/Filed Dates:March 19, 1974 / April 17, 1972

Further Reading on Touch Screens
History of Elo TouchSystems
Introduction to Touch Screens
Common Uses for Touch
The touch screen is one of the easiest to use and most intuitive of all PC interfaces, making it the interface of choice for a wide variety of applications. A touch interface allows users to navigate a computer system by touching icons or links on the screen.
Anatomy of Touch Screen
As used with a PC.
Comparing Touch Technology
There are several types of touch screen technologies that are available.

5-wire Resistive Touchscreen Technology
Surface Acoustic Wave Touchscreen Technology
Capacitive Touchscreen Technology
Glossary of Touch Screen Technology

Related Information
Computer Peripherals