You’re right about that first part but wrong about the second: the first ionization smoke detector was invented by Duane D. Pearsall of Statitrol Corporation around the late 1960s, while the photoelectric smoke detector was invented by Donald Steele & Robert Emmark of Electro Signal Lab (ESL) in the early 1970s. Prior to those eras automatic fire detection either didn’t exist or was done through heat detectors.