Rengo Co., Ltd. (Head Office: Kita-ku, Osaka; President & CEO: Kiyoshi Otsubo) announces that it has successfully developed Gaiaphoton, a brand new type of luminescent phosphor that does not contain rare earth.

Throughout the world the price of rare earth, the raw material for phosphors, is rapidly rising, and it is becoming more scarce. Many corporations, universities, and research institutions are investigating phosphors that produce luminescence without using rare earth.

To make Gaiaphoton, the ion-exchange method¹ is utilized to support faujasite type zeolite² with silver, which is not a rare earth element. In this way a phosphor has been successfully created that does not need to be subjected to the calcination process.

Although the calcination process is not required for this new phosphor, it posses a heat resistance of 600℃ and is luminescent (477 to 550nm) when exposed to ultra-violet light with a wavelength of 350nm³ or less (see photograph). It is also possible to manufacture fluorescent fibers that contain this phosphor inside the fibers.

Safety tests have been conducted by external organizations, including tests for acute oral toxicity and primary skin irritation. This product has passed all of these tests.

Patents for this technology have already been applied for inside Japan and overseas. In the future it is expected that this technology will be utilized for lighting equipment and backlights for liquid crystal displays and in the packaging field. Rengo also plans to carry out applied development to create unique, new materials combined with the antibacterial, deodorant, and virus-resistant functions of silver containing zeolite.

Rengo won the 62nd Industrial Technology Award for its development of a rare earth free type phosphor using silver containing zeolite at the annual general meeting of the Osaka Industrial Research Association that was held on May 18.

The purpose of the Industrial Technology Award is to promote science and technology, and to encourage researchers and technicians. It is given by the selection committee for remarkable results in research, development, or industrial technology by member corporations of the Osaka Industrial Research Association, and for results that were accomplished at the Osaka Municipal Technical Research Institute.

In the past Rengo has won this award for its development of Viscopearl (porous cellulose beads; 1998) and Cellgaia (pulp that zeolite crystallized at high density; 2005). This is the third time that Rengo has won this award.

Rengo intends to present its research results on fiber to prevent falsification at The Cellulose Society of Japan's 19th Annual Meeting (to be held at the Noyori Conference Hall of Nagoya University's Higashiyama Campus) in July of this year.