Nagaoka, Sadao; Shimbo, Tomoyuki; Tsukada, Naotoshi - Institute of Innovation Research, Hitotsubashi University - 2006
This paper examines the structure and the evolution of the patents declared as essential for three major technical standards in information technology (MPEG2, DVD and W-CDMA). These standards have many essential patents, which are owned by many firms with different interests. Many patents have...