Tapping into touch screens
Most of us are pretty familiar with touch screens. We use this technology daily with our phones, computers, at the ATM, or at the grocery store checkout. Even restaurants have implemented touch display ordering and payment right at the table. Even though we’re constantly tapping and swiping our screens all day long, few of us can actually answer the question: how do touch screens work?
We’re here to help uncover the mystery behind these interactive screens. Together, we can finally dispel the rumor that touch screens are operated by miniature robot elves completing your pointer finger’s many commands. Let’s discuss the most common touch screen technologies, how you can differentiate them, how they work, and how these technologies have impacted our daily lives.
Capacitive vs resistive touch screens
With the first touch screen debuting in 1965, we’ve seen incredible advancements in touch screen technology and computing technology in general. If we told E.A. Johnson that over 2 billion people currently carry touch screens in their pockets every day, he probably wouldn’t have believed us. But that same technology he developed for the Royal Radar Establishment helped shape the future of the modern touch screen technology that we use daily [1].
There are many iterations of touch screen technology including infrared and surface acoustic wave (SAW), but there are two that most of us are familiar with. The most common screens we interact with today are capacitive and resistive touch screens. Let’s get to know how these technologies work, and where you’ll see each.
Capacitive touch screens
Capacitive touch screen technology is the style we interact with most. This is the kind of display we see in our smartphones, laptops, and tablet screens, and
Capacitive screens are made up of multiple layers of glass and plastic, coated with a conductor material like indium tin oxide or copper. This conductive material responds when contacted by another electrical conductor, like your bare finger. When you touch your screen, an electric circuit is completed at the point where your finger makes contact, changing the electrical charge at this location. Your device registers this information as a “touch event.”
Once a touch event has been registered, the screen’s receptors signal this event to the operating system, prompting a response from your device. This is the application’s interface that you experience.
Capacitive touch screens generally have a brighter, clearer appearance and are much more sensitive than resistive touch screens. We tend to see capacitive touch screens in more modern technologies like smartphones and tablets. They give us the ability to experience high-quality imagery that imitates reality.
With social media so integrated into our lives, we’re constantly sharing and experiencing life through our devices. Being able to interact with high-quality applications with ease is made possible with the latest capacitive touch screens.
Resistive touch screens
Resistive touch screens work exactly how their name implies - with resistance to touch. A glass or hard plastic layer is blanketed by a resistive metallic layer that conducts charge. The two are separated by spacers in the screen so that when your finger presses firmly on the plastic protective layer, the two layers make contact changing the electric charge at that location, which cues the software to respond.
Resistive screens are not as bright as capacitive because of their thick blue and yellow colored layers that make their interface appear darker than capacitive screens. You’ll often see resistive screens used on ATM machines, checkout stands, and POS (point of sale) terminals. They tend to be much more durable and affordable than capacitive screens, thanks to that hard plastic outer layer.
Each screen has strengths and weaknesses that make it a better choice for certain applications. Capacitive screens with offer more flexibility in functionality as resistive screens lack the ability to register multiple touch points at the same time.
Think about when you zoom in on your smartphone - you’re using two fingers at different receptors to zoom in on an image. Resistive touch screens get confused when you try to apply multiple points to them, since their technology relies on recognizing pressure at a specific location.
