Sony Ericsson and Motorola today announced a definitive agreement under which Motorola will acquire a 50% interest in UI Holdings BV, the parent company of UIQ Technology AB, which is currently wholly owned by Sony Ericsson.

Under the agreement, Motorola and Sony Ericsson will work together and jointly invest in the development of the UIQ open user interface platform. Terms of the agreement were not disclosed. As previously announced, Sony Ericsson acquired UIQ Technology from Symbian Ltd in February 2007.

UIQ Technology licenses the UIQ open user interface and development platform to mobile phone vendors around the world. Motorola and Sony Ericsson are committed to further advancing UIQ as a strong, independent cross-vendor user interface for smartphones and media-centric phones.

Sony Ericsson and Motorola each have been UIQ licensees for many years and have launched several successful Symbian/UIQ based products including, the Sony Ericsson P1 smartphone, the new W960 Walkman phone and the Motorola MOTO Z8. UIQ, offered the industry’s first touch-screen interface back in 2002, and now supports both QWERTY and classic numerical keyboard configurations as well as finger touch data input. UIQ’s single code base greatly simplifies customization for handset vendors, operators and third-party developers.