Image: HTC Touch Diamond
HTC
HTC's Touch Diamond screen is a "resistive" type of touchscreen, comprised of several layers, and the most common type of touchscreen for a phone.
By
msnbc.com contributor
updated 12/15/2008 9:24:28 AM ET 2008-12-15T14:24:28

Touchscreen phones are among the hottest phones out now, with the iPhone 3G, the Google Android G1, HTC’s Touch Diamond and the BlackBerry Storm leading the pack.

But after some comparison shopping it becomes clear that not all touchscreens are created equal. Some won’t work if you have gloves on and some are slow to respond.

Other models have a nearly perfect interface between your finger and the phone; menus flow smoothly with a flick and gestures zoom and pan complex Web pages. That’s why it’s definitely wise to try before you buy if you’re considering a touchscreen phone.

Touchscreens perform differently from phone to phone because various technologies — for both hardware and software — are at work.

Image: LG Dare
LG
LG's Dare uses a resistive touchscreen.
Resistive touchscreens
The most common type of touchscreen, featured on the LG Dare, Samsung Instinct, HTC Touch Diamond and many other phones, uses “resistive” technology.

Resistive screens are comprised of several layers. The top layer, usually a clear polyester film, is flexible. When a finger presses down, the top layer comes in contact with a lower glass layer. The voltage is measured and the location of the press is computed.

Resistive screens are “the workhorse of touchscreen technologies,” said Andrew Hsu, strategic and technical marketing manager at Synaptics, a company that specializes in touchscreen technologies.

“Resistive touchscreens have, during the last two decades, delivered on the promise of sturdy, reliable and economical touch-based user interaction on a variety of applications,” he said.

Input is possible with fingers, both bare and gloved, as well as with a stylus. In Asia, where a character alphabet is used, a stylus and handwriting recognition are necessary, so resistive screens are hugely popular there.

The downsides to resistive screens include less-than-perfect transparency, scratch-prone surfaces and components that wear out and break over time.

In most Western countries, resistive technology is falling out of favor with touchscreen fans.

Capacitive touchscreens
Apple’s iPhone, the G1 and BlackBerry Storm all use the more sophisticated “capacitive” technology.

Capacitive touchscreens work well with crystal-clear glass as the touch surface. A circuit board sensor beneath the glass registers changes in electrical capacitance, or charge, when activated by a finger’s electrical charge.

The Android-powered G1 and BlackBerry Storm both use Synaptics’ ClearPad capacitive technology.

“No pressure is necessary to activate the capacitive sensor,” said Hsu. “A gentle stroke or glide along the surface of a capacitive pad is all that is required. There are no moving parts to wear out over time, and with a rated life of over 1 million uses, Synaptics ClearPad and TouchPad will probably outlast your device.”

The differences between using a phone with capacitive and resistive screens can be striking: the iPhone’s bright, bold display makes the LG Dare or Samsung Instinct seem dim in comparison.

Apple’s slick multi-touch gestures, such as pinching and spreading two fingers to zoom and reduce on-screen objects, are only possible on a capacitive screen.

Limiting capacitive touchscreen appeal, especially in Asia, is the need for a special capacitive stylus. Also, a bare finger is required for operation since the body’s electricity is blocked by gloves.

In a recent report, ABI Research noted that Asia’s need for screens “that support handwriting recognition input with a stylus” is the main reason why capacitive touchscreen phones will “not be the wave of the future for most mobile phones.”

And any phone with a glass screen, including the iPhone and BlackBerry Storm, requires extra care. Web discussion forums are jammed with customers' tales of iPhone screens shattered after being dropped.

Hardware technology is only part of what makes touchscreen phones work. The software, from the operating system to the user interface, is every bit as critical for usability.

“Touch-based technology is becoming an increasingly visible and integral component, but touch innovation is no longer about just adding a touchscreen to a device,” said Peter Recchi, HTC’s director of product management.

“Today, true touch is about the deep integration of touchscreens with intuitive touch interfaces. This is what makes touch special and natural.”

iPhone's strong user interface
The iPhone, the gold standard for touchscreen success, is the unique product from a company renowned for delivering superb user experiences.

“Apple's core competitive advantage is combining hardware and software into a compelling, intuitive user experience,” said Chris Crotty of DisplaySearch research firm.

“Other phone makers can add touch technology, but they have not been able to match Apple's strength in utilizing that touch technology with a strong user interface.”

Tim Bajarin, a technology consultant, president of Creative Strategies and an analyst familiar with Apple, said the company has “the most focused team of experts dedicated to this kind of interface, and they have been at it for a long time.

Image: IPhone 3G
Courtesy of Apple
Apple's iPhone uses a "capacitive" touchscreen, also used in the BlackBerry Storm and Google's G1 phone.

“Remember, they perfected the graphic user interface, and from that same lab came their user interface for their touchscreens. Bottom line is that Apple just knows how to do software better than just about anybody else, and more importantly, have a flawless execution behind it.”

While the iPhone enjoys unprecedented popularity, other companies are designing their own touchscreen smartphones to satisfy consumer tastes.

Combo approach
Taiwanese-based HTC, whose smartphone line includes the Touch Diamond and Touch Pro, has taken its own approach to hardware and software integration.

HTC favors customizing Microsoft’s well-established Windows Mobile smartphone operating system. (Msnbc.com is a joint venture of Microsoft and NBC Universal.)

“For devices with resistive touchscreens such as the HTC Touch Diamond and the HTC Touch Pro, HTC created TouchFLO 3D, an application that operates as a layer on Windows Mobile, and allows many features such as contacts, e-mail, and web surfing to be executed at the touch of a finger,” said Recchi.

The TouchFlo 3D interface transforms Windows Mobile Professional, which is primarily designed for use with a stylus, into a touch-friendly interface, with larger icons and iPhone-esque graphical tools for browsing music and photos.

HTC also makes the G1, the first touchscreen smartphone to use Google’s Android software. The G1’s capacitive screen, using Synaptic’s ClearPad technology, enables fluid scrolling and simple dragging and dropping of application shortcuts across the home screen for personalization.

Haptic feedback
Beyond resistive and capacitive touchscreens, new technologies are beginning to enter the marketplace.

“Haptic” feedback, where a physical sensation is used to enhance the touch experience, is already featured in smartphones such as LG’s Dare and the Samsung Instinct. With haptic feedback, a slight vibration from the screen signals when a touch command registers.

Research In Motion’s new BlackBerry Storm haptic touchscreen uses the entire screen as a clickable button.

The Storm “provides the best haptic experience of any touchscreen device at the moment,” said Stuart Robinson, Strategy Analytics’ director for handset component technologies.

He sees haptic technologies continuing to evolve, including Nokia's "Haptikos" haptic feedback "invention. It would basically mean instead of needing to look at a screen before touching it, users would be able to identify different on-screen objects by the intensity of haptic feedback.

It "looks very promising, though there's no guarantee it will make it to market," Robinson said.

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