Touchscreens explained: Capacitive and resistive technology compared
February 13th, 2011
Not all touchscreens are created equal. In this article, we review the different technologies used in touchscreen phones.
Touchscreen phones have become more popular over the last few years. By removing a physical keypad, touchscreens free up more space to display rich multimedia content. They’re also a lot more intuitive to use: a QWERTY keyboard can be used to input texts and gestures such as “pinch to zoom” and scrolling make it easy to browse through your photos and web pages.
In this article, we look at the technologies used to create touchscreen phones and some of the terminology used in the industry. We also explore the key differences between different types of touchscreen phones.
How do touchscreens work?
There are two different types of touchscreens:
- Resistive (Pressure sensitive)
- Capacitive (Sensitive to your body’s electric field)
Traditionally, most touchscreens have been built using resistive technology although in recent years, the industry has moved towards capacitive technology for touchscreens.
What is a resistive touchscreen?
Resistive touchscreens are pressure-sensitive. They work by detecting the amount of force which is applied to the screen. It doesn’t matter how you apply the force: you could press it with your finger, use a stylus or prod it with a stick. It really doesn’t matter. Generally you’ll have to apply a fair bit of pressure (a fair bit of force in a small area) to a resistive touchscreen for it to register a response – most people use the tip of their fingernail or occasionally a stylus (by reducing the area of contact you increase the pressure applied).
Resistive touchscreens consist of two surfaces separated by a resistive material. The surfaces are flexible so by applying a force to the screen, the two sheets will be pressed together. This changes the resistance between the two surfaces. The touchscreen measures this change in resistance.
As the oldest and simplest touchscreen technology, resistive touchscreens are cheap to produce. For this reason, they tend to be found in older or cheaper phones.
What is a capacitive touchscreen?
Capacitive touchscreens are sensitive to your body’s electric field. Capacitive is now the dominant technology for new high-end smartphones such as the Apple iPhone, HTC Desire and Blackberry Torch. Because capacitive touchscreens simply “sense” the existence of your finger electrically rather than requiring you to push down on the touchscreen they tend to be much more responsive. For example, it’s possible to simply glide your finger along the screen (e.g. unlock gesture) – something which is difficult with a resistive touchscreen.
Disadvantages of capacitive touchscreen technology is that you cannot used it with gloves on (your body’s electric field cannot pass through the glove) and it cannot be used with a traditional mechanical stylus. Special capacitive touchscreen styluses are available.
Capacitive touchscreen technology also tends to be more expensive and is hence seen mainly in higher-end smartphones. Prices have been coming down however… for example the Orange San Francisco is available for £99 on Pay As You Go and includes a capacitive touchscreen.
What about multi-touch?
Multi-touch simply refers to a touchscreen implementation which can detect more than one finger at once. This can be used for advanced gestures such as “pinch to zoom” (seen on the iPhone and Android). Multi-touch screens are generally built on capacitive technology.
Which touchscreen technology is better?
The general consensus in the industry is that a capacitive touchscreen is the way to go. It’s a more pleasant experience being able to use your finger rather than a finger nail or stylus and the touchscreen is much more responsive. With the costs of capacitive technology falling rapidly, it’s difficult to find a reason to choose resistive technology over capacitive technology unless you regularly use your phone in cold climates/outdoors where you’ll be wearing gloves.
What type of touchscreen technology do the latest smartphones have?
Almost all of the latest high-end smartphones feature capacitive technology (Apple iPhone, HTC Desire, HTC Wildfire, Samsung Galaxy S, Blackberry Torch, Nokia N8, etc). Generally resistive technology will only be found in older or low-end touchscreen phones.
Are there any phones available with both a hardware keyboard and touchscreen?
Yes. The Blackberry Torch 9800 is the most notable example of a phone which features both a touchscreen and a hardware QWERTY keyboard for rapid text input. The HTC Desire Z is a notable Android-based alternative.
Where can I buy a touchscreen phone?
All of the major UK networks stock a large selection of touchscreen phones:
| About Ken | |
 | My mission is to demystify the world of mobile technology for general audiences and to communicate how mobile technology can enhance every aspect of our daily lives. I've been maintaining the Ken's Tech Tips website since 2004. I have experience communicating mobile technology and presenting new mobile products both online and offline, including at various trade shows and events. You can check out my profile or drop me an e-mail. |
- How Tos & The Basics , Mobile , Smartphones
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