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September 1, 2014

Rengo Successfully Develops Gaiaphoton γ, a New Revolutionary Type of Phosphor That Is Luminescent When Exposed to Visible Light Without Using Rare Earth
Selected for the NEDO Rare Metal Replacement/Reduction & Energy-Saving Material Development and Commercialization Grant Program

Rengo Co., Ltd. (Head Office: Kita-ku, Osaka; Chairman, President & CEO: Kiyoshi Otsubo) announces that it has successfully developed Gaiaphoton γ (gamma), a new phosphor that does not contain any rare earth element yet is luminescent when exposed to visible light.

Additionally, the result of this development has been selected as a “project for the development of a zeolite phosphor containing silver (Ag), but not Europium (Eu), Cerium (Ce), or Yttrium (Y), and research related to its use,” as part of the FY2014 Rare Metal Replacement/Reduction & Energy-Saving Material Development and Commercialization Grant Program of the New Energy and Industrial Technology Development Organization (NEDO). With the goal of commercializing Gaiaphoton γ in about two years, Rengo plans to continue its research and development work to improve the emission intensity and better understand the thermal deterioration characteristics.
(NEDO website: http://www.nedo.go.jp/news/press/AA5_100294.html)

Gaiaphoton γ is an improved version of Gaiaphoton, a completely new type of phosphor that was developed without the use of any rare earth element (see the news release of June 2012), yet is luminescent (590 to 630 nm, or madder red to red) when exposed to visible light with a wavelength of 410 nm (purple). Until now, the need for exposure to ultra-violet light with a wavelength of 350 nm or shorter has hindered widespread commercialization of UV-emitting LEDs. However, Rengo has overcome this problem and established a basic recipe for expressing the three primary colors of light with exposure to visible light.

All existing phosphors use rare earth elements as raw materials, most of which are produced in and imported from China and other countries. Consequently, the supply of these elements is affected by the policies of the exporting countries and prices have remained high. In particular, the prices of phosphors that emit red light are extremely high. To make Gaiaphoton γ, however, silver is used, which is not a rare earth element and is produced in various countries. The ion-exchange method is utilized to support silver with zeolite. The new phosphor is an epoch-making product that requires no baking process, using significantly less energy during its manufacture, and is expected to be several times lower in price. Furthermore, a grain diameter of 3 to 5 µm makes the new phosphor ideal for use in LED lighting, and therefore, Gaiaphoton γ is expected to be used in LED lighting as well as a broader range of applications.

Count on Rengo with its “Growing beyond packaging through innovation” philosophy to continue producing innovative products.

 

Luminescence of Gaiaphoton γ

Luminescence of Gaiaphoton γ

 

Luminescence of Gaiaphoton γ


These photographs show how exposure to visible light with a wavelength of 410 nm causes the yellow phosphor to become madder-red luminescent (on the left side), and the white phosphor to become red luminescent (on the right side).