Rumors are that the iPhone 5 will have a 4-inch screen compared to 3.5-inch screens on the Apple smartphones that came before it. If so, it’s a screen expansion that’s perfectly timed.

According to The NPD Group (http://www.npd.com), a market research company, U.S. consumers are willing to give up room in their pockets and handbags to gain a richer media experience on their mobile devices. The U.S. market share for iPhones and other smartphones with screen sizes between 3.5 inches and 3.9 inches have remained steady, but smartphones with the largest screens (four inches or larger) have grabbed market share from devices with screen sizes that are less than 3.5 inches.

Based on the latest information from NPD’s Mobile Phone Track, smartphones with 4-inch-or-larger screens, like Samsung’s Galaxy S, HTC’s EVO 4G and Motorola’s Droid X, which debuted in the second quarter (Q2) of 2010, quickly grew to encompass 24% of the market by Q4 2010. The market share for iPhones and other smartphones with screen sizes between 3.5 inches and 3.9 inches increased 2% over the prior year’s Q4; while the market share of smartphones with screens smaller than 3.4 inches, declined from 63% in Q4 2009 to just 36% of the smartphone market in Q4 2010.

“The explosion in Web and video content available for smartphones has caused consumers to rethink their phones’ sizes,” says Ross Rubin, executive director of industry analysis for NPD. “Larger displays offer a richer media experience, as well as a roomier surface for on-screen keyboards. Handset vendors are continuing to push the envelope of pocket real estate to complement the video capabilities of 4G handsets.”

While men still make up the largest share of consumers purchasing smartphones with the largest screen sizes, women are increasingly likely to buy them. In Q2 2010 just 30% of large-screen smartphone purchasers were women, but by Q4 2010 women represented 40% of large-screen smartphone sales.

Apple is usually ahead of the curve, so you can expect the company to capitalize on the desire for bigger smartphone screens with the iPhone 5.

— Dennis Sellers