Electrochromic, Gaschromic Technologies Featured at Trade Show (1)

Feb 8, 2013
Tetsuo Nozawa, Nikkei Electronics
The EC glass developed by AIST and Towa. The color of the upper left panel is original. And various colors are created by placing a color film on it.
The EC glass developed by AIST and Towa. The color of the upper left panel is original. And various colors are created by placing a color film on it.
[ If it clicks, the expanded picture will open ]
The colors of the panels changed by switching voltage levels
The colors of the panels changed by switching voltage levels
[ If it clicks, the expanded picture will open ]
An interior accessory that Towa prototyped by using an EC glass
An interior accessory that Towa prototyped by using an EC glass
[ If it clicks, the expanded picture will open ]

Several light control glasses and displays using electrochromic (EC) and gaschromic (GC) technologies were exhibited at nano tech 2013, which took place from Jan 30 to Feb 1, 2013, in Tokyo.

The development of such technologies is seemed to be accelerating after EC technologies were employed for the windows of the Boeing Company's "B787."

EC technologies use a phenomenon in which the optical properties of a material are changed by applying a voltage to the material to cause a reversible oxidation-reduction reaction for changing the color, etc of the material. Though they have long been studied, there are not many commercialized EC technologies.

In such circumstances, Boeing employed EC technologies for the windows of the B787, enabling to electrically switch colors between a transparent state and a deep blue state. As a result, EC technologies are becoming widely known.

The Green Technology Research Group of the Nano System Research Institute at Japan's National Institute of Advanced Industrial Science and Technology (AIST) and Towa Co Ltd exhibited an EC glass made by spraying a liquid solution at nano tech 2013.

The glass was made by forming the "/ITO" structure including ITO/EC materials between two glass plates. For the EC materials, Prussian blue (PB) and materials similar to PB were used. As a result, it became possible to switch colors between blue and yellow by changing voltage levels. Also, the number of colors can be increased by using color films.

The applied voltage is 1.2V. The performance of the glass does not deteriorate even after switching voltage levels more than one million times, AIST and Towa said.

Such glasses equipped with electronic shutters can be realized by using LCD technologies and have actually been realized.

"LCD technologies deal with complicated structures, making it difficult to make such glasses at low costs," AIST said. "On the other hand, the new EC glass can be manufactured at low costs because it can be made by using coating techniques."

It expects that the new glass will be used for interior accessories and light control glasses.

Go to next story