How Do Touch Screens Work?
Touch screens are becoming more prevalent in today’s technology.
CREDIT: bloomua | Shutterstock
Touch screens are visual displays that act as an input device, responding to the touch of a finger or a stylus. Rather than using a mouse to navigate a screen and click on elements, touch screens instead allow users to touch parts of the screen they wish to interact with.
As technology advances and the cost to produce technology decreases, touch screens are a prevalent part of how we interact with devices. Desktop PCs, laptops, tablets, smartphones and other devices now use touch screens as an interactive tool.
How touch screens work
While the functionality of touch screens is dependent upon the type of technology used as an input device, the core fundamentals remain the same. Touch screens register touch events, or when the screen registers an interaction of some kind, either through a finger or stylus. The screen then registers the location of the event and submits the data to a controller, which interprets how the device will react.
When you touch an app, flick your finger across the screen, or double tap, the screen registers all events and helps the device react appropriately — launching apps, turning pages or zooming in accordingly. How touch events are registered varies among touch screens, as many different types exist. Of the countless touch screen options in circulation throughout the world, three are the most common: resistive touch screens, surface wave touch screens and capacitive touch screens.
Resistive touch screens
Touch screens with a resistive feature are coated with a metallic and electrically conductive layer that tracks changes in electrical current. Changes occur when a touch event happens, which is then sent to the controller for processing. While resistive touch screens are the cheapest option and common in many Android smartphones, they also prove to be the most problematic with only 75 percent clarity, which is why on some devices you have to push harder for it to register any touch events. In addition, the screen can easily be damaged by sharp objects.
Surface wave touch screens
Through the use of ultrasonic wave technology, this type of touch screen is able to track touch events through wave absorption. When you touch the screen, it creates a small ultrasonic wave that is absorbed partially into the screen. The screen is able to track differences between static ultrasonic waves and those created by actual touch events, which makes this technology among the more advanced of options. The downside, however, is that this touch screen can easily be damaged by outside elements like dust or water.
Capacitive touch screens
Commonly used for Apple products, capacitive touch screen panels are coated in a material that stores electrical charges. When a touch event occurs, the charge is drawn to the point of contact due to the conductive nature of the human body. Circuits placed at each corner of the panel would then measure the charge to determine the type of touch event before sending to the controller for processing. The technology thus requires that screens be touched with a finger and aren’t compatible with styluses.
The history of touch screens
Early mentions of work on touch screens date back to 1965 with E.A. Johnson’s work on capacitive touch screens. In the 1970s, engineers from CERN began work on developing their own transparent touch screen, which was then produced and used by the facility. The first resistive touch screen was produced in 1982, which paved the way for the modern stylus.
In the 1980s, General Motors began work on its own touch screen technology, eventually producing what was then called an “electronic control center.” The device was used in the company’s Buick line of cars and effectively replaced the controls and displays for stereo, fan, heater and air conditioner. Due to the early nature of the technology, it was quite costly to repair and very prone to electrical issues.
It wasn’t until the surge of popularity among PDA devices that touch screens truly began to gain momentum. While the screens used resistive technology and thus required the use of a stylus for use, the technology proved quite reliable and offered countless practical applications to the businessperson. At the turn of the millennium, touch screens still struggled to gain traction despite the popularity of PDAs. In 2004, the first successful touch screen handheld game console was released, the Nintendo DS.
Shortly thereafter, the technology began to break into the mobile phone arena. With the release of the first Apple iPhone in 2007, touch screen technology on cell phones quickly became a highly-requested standard feature and helped pave the way to the current prevalence of touch screen technology.
Whether you own a smartphone, tablet, laptop or desktop monitor, touch screen technology is becoming more and more a part of the modern end user experience. Touch screens allow for a more direct means of interacting with a device and opens up a whole world of possibility. As excess hardware like mice and keyboards are eliminated and devices become more dependent on this type of functionality, you should expect to see the application of touch screen devices increase drastically.