Tablet shipments are expected to eclipse notebook sales, a new study shows.

A report by market research firm DisplaySearch [5] found that  tablet purchases are expected to surpass PC use for the first time this year, less than three years after the iPad debuted in stores.

The consulting firm estimates that 207 million notebooks will be shipped in 2013 to the 240 million tablets -- a 64 percent rise in the flat-top computers.

By 2017, the firm reckons tablets will constitute nearly 75 percent of the combined tablet-notebook market worldwide.

For this year, the firm expects that 7- to 8-inch screens, like those on Apple's iPad mini or Google's Nexus 7, will triumph as the most popular-sized screen.

For 2013, the research group predicted those will account for 45 percent of the market, eclipsing the original, 9.7-inch sized iPad -- which will make up 17 percent, its study showed.

The numbers dramatically accelerate Display Search's earlier predictions. Last summer, the company said [6]that tablets computers are expected to overtake sales of notebook computers. However they said the change would take place not this year, but by the end of 2016.