Sony and Amazon have e-books on the market. LG is trying to do them one better by releasing one with an integrated solar panel.

The integrated thin-film solar panel is around 9.6 percent efficient and adds about 20 grams to the weight of the e-book, according to Tech-On!, a website that covers Asian technologies. Put the e-book in the sun for four to five hours and it will run for a day. That makes it a little more functional than Sharp's solar cell-enhanced phone. Putting the phone in the sun for ten minutes gives you about a minute of talk time.

"E-Books are attracting a lot of attention because they offer the advantage of storing thousands of books worth of content in an easy-to-carry device," Ki Yong Kim, head of the Solar Cell Office at LG Display, told Tech-On.

E-books have long looked for their breakout moment. Two companies, including one founded by Tesla co-founder Martin Eberhard, flogged the concept in the late 1990s. Customers didn't bite. Sony's e-book from two years ago didn't rocket up the charts either. But the Kindle from Amazon has done surprisingly well, a clue that maybe the customer acceptance is occuring this time around. Electronic books can save paper and fuel consumed in transportation.