SED TV Tech Is History
The acronym stands for Surface-conduction Electron-emitter Display. Like the cathode ray tube, it fires electrons from back to front where they light up colored phosphors. But while CRT uses a single electron gun, SED uses a lot more emitters, one per pixel. That enables it to be much flatter than a CRT while still enjoying some of the tube's strengths such as black level.
Unfortunately Canon did not choose its technology partners wisely. It got involved with Texas-based Nano-Proprietary. When Canon brought Toshiba in for its experience in making and marketing TVs, Nano objected strenuously and years of litigation began. By the time Canon wiggled free of Nano, SED's moment had passed.
The company is not discontinuing its SED effort entirely. Industrial uses may still be explored. But forget about a consumer-level SED.