Toshiba has apparently leaped far ahead of its competitors with the unveiling of the first large-screen, glasses-free 3D television set. The 55-inch set employs a face-tracking system that it claims delivers a 3D picture that is personalized for up to nine people sitting in a room. (Unlike some smaller glasses-free 3D sets from other manufacturers, viewers do not need to sit directly in front of the set in order to experience the 3D effect.) The set, which also boasts four times the resolution of current high-definition TV sets, was unveiled today (Friday) at the IFA Consumer Electronics Show in Berlin. It is expected to go on sale in time for the holiday shopping season in December. Its principal drawback -- at least for the present -- is its price -- more than $11,000. Still, the set could represent a particularly brutal blow to Sony, which has been seeking to revitalize its consumer products division and which has managed to take the lead in the production of 3D television sets. Its current models require battery-operated glasses, and its glasses-free model is still in the development stage.