Beneath the surface: The state of the touchscreen market

Following the iPhone's smashing debut in June 2007, the touchscreen has grown in popularity and become a big focus for handset makers and wireless carriers. Handset makers hope to use touchscreens to provide a richer user experience, and carriers hope the technology will make it easier for consumers to access data applications.

According to DisplaySearch, the touchscreen market for mobile phones is expected grow significantly over the next few years. In 2008, touchscreen penetration for mobile devices was 15.8 percent--and by 2015 it is expected to grow to 40 percent. Last year, touchscreen modules for mobile phones represented a $900 million market, and by 2015 the market will grow to $3 billion. "Touch is so intuitive," said Jennifer Colegrove, director of display technologies at DisplaySearch, a research firm specializing in touchscreen displays.

Resistive vs. projected capacitive

While there are a slew of touchscreen technologies on the market, only a handful work well with mobile phones. The two dominant touchscreen technologies are resistive and projected capacitive.

Resistive touchscreens first appeared on handsets in the 1990s on devices like the Palm Pilot, but capacitive touchscreens didn't hit the handset market until 2007. Generally, resistive technologies require users to actually press or push down on a top panel, which makes contact with underlying rigid substrate. Then the location of the touch can be computed.

Andrew Hsu, the strategic and technical marketing manager at Synaptics, a company that focuses on end-to-end capacitive touchscreen solutions, described resistive touch as, essentially, "a very big, wide switch."

Projected capacitive technology, by contrast, is a solid-state system in which invisible electrodes beneath the top display surface report a difference in capacitance once a user's finger comes near, thereby computing the finger's location. Users don't have to press down on the screen to get a response.

Each technology has its pros and cons. Since resistive technology has been around longer, and there are more phone models on the market using it, it has a greater economy of scale and is cheaper to produce. Resistive touchscreens are also better at handling input from styluses and long finger nails. However, since resistive touchscreen users are actually pressing down on the screen, the displays tend to be less durable. Another significant disadvantage is that resistive technology does not support multi-touch.

Multi-touch, as epitomized by the experience on the iPhone, is one of the biggest advantages to projected capacitive technologies, and is what's drawing handset makers to it. Other advantages for projected capacitive include greater durability and better optical clarity. However, capacitive touchscreens are, right now, more costly than resistive, and more complicated to implement.

Cutting the cost

The question of cost is not something that is lost on companies that deal with projected capacitive technologies. However, according to DisplaySearch's Colegrove, projected capacitive is getting cheaper every year, for several reasons: Chips and sensors are getting smaller and are performing better, and the market is beginning to open up.

"As more chip vendors enter the market and more glass suppliers get up to speed, we'll see continued erosion in the cost to capacitive," said Dave Carey, the president of Portelligent (better known as

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