Taiwanese AU Optronics recently signed a patent assignment agreement with IBM, acquiring 170 US patents relating to TFT-LCD technology and the counterpart patents in Japan, South Korea, Taiwan and other countries. The patents cover almost all aspects of TFT-LCD technology. Many were developed by IBM in the 1980s. In 2001 it exited the panel business by ending a LCD joint venture with Toshiba, after which it held on to its patents relating to this field.