Nokia will unveil large-screen mobile handsets next month to revamp its Lumia smartphone lineup and challenge Samsung's dominance in increasingly popular phablet devices, meaning screens that have over 5-inch screens. Nokia has developed more than one such device, but details such as specifications and price were not available. Analysts see growth in demand for large screens as more consumers watch videos and look at photographs on smartphones. A phablet would be the latest addition to Nokia’s range of Lumia smartphones which use Microsoft’s Windows Phone software.