Apple Inc. may want to watch its back; top handset manufacturers Motorola Inc. and Nokia Corp. have shown interest in iPhone-like touch screen technology this week.

    For its part, Motorola has purchased 50 percent of Sony Ericsson’s stake in UIQ Technology, a mobile software developer that provides a platform for touch screen smartphones. Motorola and Sony Ericsson will jointly invest in the development of the UIQ open user interface platform; Sony-Ericsson bought UIQ from Symbian Ltd. last February. Motorola said the move is meant to shore up its ability to compete in the market with new multimedia devices.

    Nokia Corp. meanwhile announced at the Symbian Smartphone Show that it will upgrade the Series 60 user interface for smartphones, and license it to its competitors. “The S60 will introduce new features that enhance the user experience and enable manufacturers, developers and operators to design new types of mobile devices, applications and services,” the vendor said.