3D display --- In 1926, Kenjiro Takayanagi, known as the "father of Japanese television," transmitted the image of a katakana character (?) to a TV receiver built with a cathode ray tube, signaling the birth of the world's first all-electronic television. Last week, in a symbolic gesture over 80 years later, researchers from Japan's National Institute of Advanced Industrial Science and Technology (AIST), Burton Inc. and Hamamatsu Photonics K.K. displayed the same katakana character using a 3D projector that generates moving images in mid-air.

The 3D projector, which was first unveiled in February 2006 but has seen some recent improvements, uses focused laser beams to create flashpoint "pixels" in mid-air. The pixels are generated as the focused lasers heat the oxygen and nitrogen molecules floating in the air, causing them to spark in a phenomenon known as plasma emission. By rapidly moving these flashpoints in a controlled fashion, the projector creates a three-dimensional image that appears to float in empty space.

The projector's recent upgrades include an improved 3D scanning system that boosts laser accuracy, as well as a system of high-intensity solid-state femtosecond lasers recently developed by Hamamatsu Photonics. The new lasers, which unleash 100-billion-watt pulses (0.1-terawatt peak output) of light every 10-trillionths of a second (100 femtoseconds), improve image smoothness and boost the resolution to 1,000 pixels per second. In addition, image brightness and contrast can be controlled by regulating the number of pulses fired at each point in space.

The researchers say these improvements bring us one step closer to realizing the dream of 3DTV, but considering it took eight decades for Takayanagi's primitive 40-scan-line television to evolve into our present-day HDTV, we might have a while to wait.

[Source: AIST press release]