Photo/IllutrationA prototype “micro-size reading light” roams above a book. (Provided by the University of Tokyo)

  • Photo/Illustraion

Japanese researchers have developed a light-emitting device that floats like a firefly and could lead to the creation of mid-air displays and other contraptions.

The developers include Yoshihiro Kawahara and Makoto Takamiya, both associate professors with the University of Tokyo, and Yasuaki Kakehi, an associate professor with Keio University.

The hemispherical device, with an embedded light-emitting diode, measures 4 millimeters across and weighs 16 milligrams. It can levitate and roam in mid-air when ultrasound beams are applied.

The researchers reduced its weight by using a custom-made integrated circuit and by drawing on the technology of wireless powering, or remote power transfer using electromagnetic waves, to obviate the need for a battery.

The scientists say their invention is the world’s first aerially mobile compact light-emitting object with an embedded electronic circuit. They named it “Luciola,” after part of the scientific name for Genji, a firefly species common in Japan.

The researchers have already made a prototype “micro-size reading light,” which roams above a book.

They said they plan to study how to combine a large number of Luciola devices to display aerial images.