Touchscreens are a popular, innovative technology applications found in various entertainment, communications and customer service devices. Touchscreens to control devices and use interfaces without the aid of instruments like physical mouse devices and keyboards. Touchscreen interaction works by either tactile digit or stylus pointing and gesturing. While the technology was heavily developed in the past two decades, touchscreens emerged in the 1940s.
Some touchscreen interaction methods require stylus use, while others can be operated simply by the human hand. These methods rely on different grid controls that pinpoint cursor location based on resistive touch, heat sensors, acoustic disturbance, and electric conductance. Because of certain ergonomic concerns related to user comfort and capabilities, there are general principles for designing and implementing touchscreen technology in certain non-mobile applications.
The Basics of Touchscreen Operation
There are three basic methods of touchscreen operation, each with several variations.
A resistive touchscreen involves an electrical current that is disrupted by touch from both inorganic and organic instruments. There are multiple layers around this current: two metallic layers, one conductive and one resistive, which are separated by a very small space through the current flows. The metallic layers are above a pane of glass, and below a scratch-resistant layer. When an instrument such as a stylus or a finger touches the top layer, the slight pressure causes the metallic layers to connect. The computer elements of the touchscreen device can then calculate the precise location of current disruption, allowing interface operation.
Surface Acoustic Wave
Surface acoustic wave technologies transmit ultrasonic acoustic waves across a layer of reflectors. When a finger touches the screen, the waves are disrupted and the computer can calculate the touch location. Surface acoustic wave is generally one of the crispest image quality touchscreen technology options, because it does not use metallic parts and allows 100 percent light translucency.
Capacitive touchscreens incorporate electric charges beneath a charge-storing glass panel. When a conductive instrument touches the panel, the charge is directed by chips beneath the panel that determine the touch location. Capacitive touchscreens also provide good image clarity, because of the tendency to use glass parts.
Information about further distinctions between these touchscreen methods and their variations can be found at http://www.touchscreens.com/intro-touchtypes.html.
Other Touchscreen Information and Considerations
In addition to touchscreen type, there are ergonomic concerns for touchscreen user consideration. Because touchscreens are common features of mobile devices, arm strain is not typically a concern, but when applying touchscreen functionality to a mounted device, it can cause problems. Mouse and keyboard use for a typical desktop or laptop computer relies on the user’s arms being horizontal on the table, but a touchscreen requires the user to extend his or her arms and hold them aloft for longer periods of time. This can cause strain and exhaustion, and result in the user choosing a different device.
Additionally, touchscreens rely on various types of physical input. Because capacitive touchscreens operate via conductive touch, typically a user’s fingers, the screen can be dirtied by fingerprints. Most capacitive touchscreens have incorporated oleophobic coatings, which are chemicals that resist adherence to oils, specifically oils common on human skin. For other types of touchscreens that rely on a stylus or other inanimate tool for interaction, it is necessary to find scratch-resistant glass or coating for the upper layer of the device, so as to prevent dents and discoloration on the touchscreen.
Touchscreen devices are common on portable devices, such as cellular telephones, digital music devices, and handheld organizers, some of which are intended for use in rugged environments. Touchscreens rely on sensitive working properties, so extreme environment can have adverse effects on their behavior and performance. For example, touchscreens intended for cold environments should probably not be capacitive, because a user will probably be wearing protective gloves and will not be able to properly physically contact the screen.