At the FPD International 2010 trade show in Tokyo Tuesday, Chinese company Hanvon Technology is set to unveil the first full-color tablet using e-ink technology.

The e-ink tablet has a 9.68-inch color touchscreen with built-in Wi-Fi and 3G connectivity. It will be available for $440 in China this March — about $150 less than the cost of a 16GB, Wi-Fi-only iPad in China.

With a 78% share of the market, Hanvon is the most popular maker of e-readers in China.

Black-and-white e-ink is currently used in the displays of 90% of e-readers, such as Amazon’s Kindle and Barnes & Nobles’s Nook, according to The New York Times.

After the success of Apple’s iPad as an e-reading device and Barnes & Nobles’s recent announcement that the second-generation Nook would use a color LCD screen (rather than black-and-white e-ink), it seemed the days of colorless e-ink devices might be numbered. The addition of color could make e-readers more exciting for consumers who dislike the relatively short battery lives and glare of tablets with LCD displays.

Still, the new e-ink displays, which are produced by laying a color filter over standard black-and-white e-ink screens, are neither as vivid nor sharp as their LCD counterparts — The New York Times likened them to “faded color photograph[s]” — nor can they handle full-motion video.

Neither Amazon nor Sony have confirmed that e-readers with color e-ink are in the works.

“On a list of things that people want in e-readers, color always comes up,” Steve Haber, president of Sony’s digital reading business division, told The New York Times. “There’s no question that color is extremely logical. But it has to be vibrant color. We’re not willing to give up the true black-and-white reading experience,” he said.

While the Nook — Barnes & Noble’s $259 e-reader and Kindle rival — has been available for purchase online since November, it has yet to be sold in the company’s brick-and-mortar stores. Come Wednesday, however, that will all change.

The New York Times is reporting, “Barnes & Noble, the country’s largest bookselling chain, said that its Nook electronic reading device would be available for purchase in its stores starting Wednesday.”

Barnes & Noble originally made a big splash with its Nook announcement in late October, but its digital book reader has since been met with mixed reviews and suffered from stock shortage problems around the holidays.

The push to finally get the Nook in Barnes & Noble stores is likely the result of the hoopla involving Apple’s iPad. As Google is learning via lackluster Nexus One sales, consumers haven’t exactly embraced the online-only purchase model when it comes to electronics. With its physical debut coming several months prior to the iPad’s, Barnes & Noble might have an opportunity to land key sales before consumers can hold the iPad for themselves.