In 1970, the World Expo in Osaka showcased the Sanyo Ultrasonic Bath, a unique washing machine for human beings. Attendees could climb into the machine and enjoy a pre-wash cycle of warm water jets, followed by a three-minute ultrasonic bath and hot rinse cycle. They would then be dried off with warm air and exposed to both infrared and ultraviolet light to kill germs. While the prototype is now stored in the Panasonic Museum and never made it to production, it has inspired Japan’s Science Group to bring back the concept for the 2025 World Expo in Osaka, with a focus on healthcare applications.
https://www.core77.com/posts/134471/A-Washing-Machine-for-Human-Beings-from-1970