According to New Scientist, Japanese researchers have developed a laser display which can produce flash dots in the air. Their system can display 'real 3D images' instead of the pseudo-3D images on 2D planes created by current devices. In addition of conventional galvanometric mirrors, this system uses a linear motor system to control the position of the laser focal point. And the researchers said that these displays, which are still in a demonstration stage, could soon be used for a variety of applications, from huge 3D ads to emergency distress signals.
Here are some details about this system provided by New Scientist.
The display utilises an ionisation effect which occurs when a beam of laser light is focused to a point in air. The laser beam itself is invisible to the human eye but, if the intensity of the laser pulse exceeds a threshold, the air breaks down into glowing plasma that emits visible light.
The required intensity can only be achieved by very short, powerful laser pulses – each plasma dot, or "flashpoint", lasts for only about a nanosecond. But the resulting image appears to last longer due to persistence of vision. As with film and television, the impression of a continuous image is maintained by refreshing the flashpoints.
This demonstration system has been built by the National Institute of Advanced Industrial Science and Technology (AIST) and Keio University, in collaboration with Burton Inc. Below is an overview of the 3D-image spatial drawing device they've developed (Credit: AIST).
And below are various images of objects displayed in the air using this system (Credit: AIST).
Here are more details about the work done by the Japanese researchers about this spatial display incorporating a linear motor system and a high-quality and -brightness infrared pulse laser, as reported in this AIST press release.
The linear motor system enables the position of the laser focal point to be varied by high-speed scanning of a lens set on the motor orbit. Incorporation of this system makes the image scanning in the direction of the z-axis possible. For scanning in the x and y axis directions, conventional galvanometric mirrors are used.
The laser light source we used in this work is a high-quality and high–brightness infrared pulsed laser (repetition frequency of pulse: approximately 100 Hz), by which plasma production can be more precisely controlled, enabling brighter and higher contrast image drawing. In addition, the distance between the device and drawing points can be greatly extended (several meters).
Finally, New Scientist adds that "this technology may eventually be used in applications ranging from pyrotechnics to outdoor advertising," according to a spokesman for AIST, while Burton Inc. thinks "it might also be used for emergency distress signals or even temporary road signs."
Sources: David Hambling, New Scientist, February 27, 2006; AIST press release, February 7, 2006
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