Touchscreens are everywhere today, but most still consider them a relatively new technology. Depending on how you define a computer, the first touchscreen computer dates back to 1965, when EA Johnson created the first touchscreen to improve air traffic control systems. However, because it had no applications beyond air traffic control, it could not be considered a full-fledged computer. Similar devices subsequently appeared, such as CERN’s touchscreen control systems for scientific equipment in 1972 and the PLATO IV, a touchscreen terminal designed to assist students, also from 1972.
However, these were specialized devices not accessible to the general public. If we talk about the first commercially available personal computer with a touchscreen, it is the HP 150 from 1983. As the name suggests, Hewlett-Packard (HP), one of the most popular laptop manufacturers today, manufactured the device. The computer consisted of two parts: a dual floppy disk drive used to install the operating system and a monitor housing the main computer hardware.
The HP 150 had a variety of legacy ports that we no longer use. It had two RS-232 ports, an IEEE-488 or General Purpose Interface Bus (GPIB) port for connecting external drives, AC input and output ports, and an RJ-11 port for a keyboard connection. Like many computers at the time, the HP 150 did not support a mouse, relying on keyboard input and its touchscreen to function. For other ports, such as parallel ports for printer connections, HP allows users to add expansion cards.
How does the HP 150 touch screen work?
The two main types of touch display technologies in use today are capacitive touchscreens, like those on your smartphone, laptop, or tablet, and resistive displays, like those you’ll find on an ATM or point-of-sale terminal. Capacitive touchscreens use two conductive layers separated by an insulating layer to create a charge on the screen. When you press your finger on the screen, the charge from inside your body interacts with the screen’s existing charge, telling the device precisely where your finger is. Resistive touchscreens consist of two conductive layers separated by a slight gap. The top layer is transparent and flexible, while the bottom layer is rigid. When you press the outer layer, it bends to complete the circuit and register a keystroke.
The HP 150 used neither, opting for an optical infrared (IR) touchscreen. In the computer monitor case, evenly placed holes contained IR emitters and receivers. These projected invisible horizontal and vertical rays of light to create a grid just above the screen. When an object interacted with the screen, it interfered with the grid projection, telling the computer where the screen had been touched.
This system was very responsive for its time, but had glaring problems that caused companies to move to capacitive and resistive technologies. First, this method only allowed one point of contact at a time; gestures like pinching were not possible. Larger glasses were also needed to correctly position the IR emitters. In addition, dust could settle in the openings provided for the infrared emitters, thus rendering the touch screen unusable.
Does HP still make touchscreen computers?
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After the HP 150, the company did not produce a touchscreen computer for more than two decades. The HP Compaq Tablet PC TC1000 was released in 2002, followed by its successor, the TC1100, but both required a special digitizer pen and did not support direct finger touch. The company’s next true touchscreen computer was the HP TouchSmart series, which debuted in 2007. These were all-in-one desktop setups featuring the same IR touch technology as the HP 150. A year later, HP introduced the HP TouchSmart tx2 in 2008, its first touchscreen computer that moved away from IR emitters in favor of capacitive touch and eventually added multi-touch capabilities. The company has since produced many other touchscreen laptops, including some models from the retired Envy, Specter and Pavilion lines.
Today, HP offers a variety of touchscreen laptop lines aimed at different demographics. The HP OmniBook line (including the OmniBook Ultra and OmniBook HP also continues to produce Chromebooks as budget alternatives with touch capabilities.
