Apple and its Asian suppliers are testing larger screens for iPhones and tablets, people at the company’s suppliers said. Apple in recent months has asked for prototype smartphone screens larger than 4 inches and has asked for screen designs for a new tablet measuring slightly less than 13 inches diagonally, they said. The current iPhone 5 has a 4-inch screen, while the iPad has a 9.7-inch screen. The iPad Mini, a smaller version of the iPad tablet, has a 7.9-inch screen. Whether the designs will make their way to market is unclear. The Cupertino, Calif., company routinely tests different designs for its products as it refines them during development. The company also changed its offerings of the iPhone and iPod last year to include larger screens, while adding the variant of the iPad with a smaller display. An Apple spokeswoman declined to comment.