I wonder where this concept of projectability in air came about. I have seen such imaginary things in films such as Star Wars and a couple of others but light requires a surface to become apparent by reflection. I have never seen it in a reliable technical source. How radium, an intensely dangerous material, comes into this fantasy is a total mystery.

Yes, it is possible, and it already exists. The technology is very expensive, and fairly experimental.

Aside from projecting on a film of water vapor which involves a setup of over 100,000 dollars a summary of other attempts is at http://www.pangolin.com/resguide03b.htm

No satisfactory true air projection.

I predict that whoever perfects this idea (assuming it's not already stolen by some patent squatter) will be *extremely rich.

1. Think about what it would do for laptops: they could be no bigger than the size needed to house the keyboard, and could project a very large screen.

2. Monitors could be placed almost anywhere, they would not have to sit on a horizontal surface anymore. If built into the surface of a desk, your monitor could effectively disappear when not in use, leaving the entire surface of the desk available.

Does "in air" mean like a hologram? Having a projector instead of an expensive screen makes sense, and the prices are dropping.