Spring Design, the maker of the Alex dual-screen ebook reader is suing Barnes & Noble over claims that the bookseller copied ideas and features in releasing its own ebook, the Nook.

"We showed the Alex e-book design to Barnes & Noble in good faith with the intention of working together to provide a superior dual screen e-book to the market", said Spring Design vice president of Sales and Marketing, Eric Kmiec in a statement.

According to the company who says they showed Barnes & Noble the Alex in spring 2009, "the lawsuit asserts Barnes & Noble misappropriated trade secrets and violated the parties' non-disclosure agreement when it copied Alex' features into its recently announced Nook e-book".

Both ebooks announced in the same week (20 October), use a colour touchscreen display powered by Android to navigate through menus, rather than the e-ink display, which is used solely for reading. 

The Barnes & Noble Nook is expected to hit the company's stores on 30 November with many stores already covered in merchandising materials and dedicated booths to lure customers to go "electronic".

Barnes & Noble was unavailable to comment at the time of writing. We will keep you posted.