TOKYO, Oct. 6 -- Visible light communications is the topic of two speakers at the CEATEC Japan 2004 information technology and electronics exhibition, being held this week in Tokyo.
Masao Nakagawa, PhD, president of the Visible Light Communications Consortium (VLCC), and Shinichiro Haruyama, PhD, vice president of the VLCC, both professors in the Department of Information and Computer Science at Keio University, say visible light communications technology -- in which data is sent via light visible to the human eye, such as LEDs -- could supplement communication that isn't feasible with only radio waves.
"One major advantage of visible light communications is that we can use the infrastructure around us without having to make any changes," Nakagawa said. "For example, the transmission of positional information entered into individual indoor LED lighting devices and sent to a cellular telephone or similar device enables position detection that is accurate to within several meters. Theoretically, precision is possible to within several millimeters, and it is at this level that the true power of visible light communications will be realized, such as in controlling robots. To give another example, all sorts of information can be sent to cars and pedestrians using LED traffic signals."
The VLCC, created in 2003, has 15 member companies and conducts visible light communications systems research and development. Four of these companies are showcasing at CEATEC the myriad possibilities of visible light communications.
The exhibits include a "light and sound collaboration" (Keio University, Agilent Technologies Japan Ltd. and Sony Corp.) in which musicians each play a different instrument under red, green and blue lights. When visitors wearing headphones face one of the lights, they hear only the sound of the instrument receiving signals from that light.
An LED traffic signal communication system (Nippon Signal Co. Ltd. and Nagoya Institute of Technology) demonstrates how visible light communications can be applied to LED traffic lights. "It will be possible to send all sorts of information from traffic signals to cars and pedestrians waiting for lights to change," Nakagawa said. "Visible light communications is beginning to receive attention as a new communications medium for intelligent transport systems."
Another exhibit (Keio University, NEC Corp. and Matsushita Electric Works Ltd.) demonstrates how visible light is used to send ID information from LED illumination on mobile phones and other mobile terminals. Even in places such as underground shopping malls, where radio waves don't easily reach, extremely accurate position information and image and text data can be transmitted instantaneously.
A demonstration by Cyber Solutions Laboratories and Nippon Telegraph and Telephone Corp. shows how a form of communication based on visible light with varying hues uses existing cellular telephone displays. Simply holding the handset up to a large screen transmits the telephone's ID, and pointing the phone in the direction of desired information on the screen prompts the information to be downloaded to the phone.
Also on display at CEATEC is a new 65-inch LCD TV from Sharp featuring the largest screen in the world; the Sony VIAO Type X combination digital video recorder (DVR)-PC, which allows users to record TV shows; and a host of thin, large-screen televisions, including LCD, plasma-display-panel (PDP), SED (surface-conductor electron-emitter display) and rear-projection models.
For more information, visit: www.ceatec.com