As a consequence of the continued rapid growth in sales, Gartner estimates there will be 2.6 billion mobile phones in use by the end of 2009.

"The world's appetite for mobile phones has exceeded even the most optimistic expectations," said Ben Wood, research vice president for mobile terminals at Gartner. "Mobile phones could go on to be the most common consumer electronics devices on the planet."

Mobile phone sales have risen steadily since a year of zero growth in 2001. In 2005, Gartner expects sales to reach 779 million units, a 16 percent increase on 2004.

The research also showed that more than 100 million 3G phones will be sold in 2006, and more than 200 million smartphones will be sold in 2008.

Mobile handsets still represent the largest market segment for high-brightness LEDs, where the devices are used as backlights for keypads and LCD screens as well as in flash units.