レイア姫じゃないけど
>As the manufacturer describes it "Heliodisplay images are not holographic although they are free-space, employing a rear projection system in which images are captured onto a nearly invisible plane of transformed air."
こっちで見たほうがキレイかも知れないけど。
http://www.io2technology.com/technology/overview
に概要があるよ！