I've just noticed that a year ago Korean SETi had been reverse merged with G-SMATT Global. The LED panel glass manufacturer G-SMATT is now trading under the former SETi ticker at KOSDAQ. G-SMATT is still selling the older SETi image sensors, but its main business is in glass manufacturing. This is pretty sad news for a company that once controlled a significant portion of Chinese image sensor market. Thanks to BS for the info confirmation!
In spite of SETi demise, Korea still has a relatively large number of smaller image sensor companies: Pixelplus, Clairpixel, ZeeAnn, Maru LSI, and Rayence.
Update: Rayence has been acquired by GE Healthcare in 2013. Thanks to RT for the info.