Naotoshi Matsuda

Luminescence Properties of Rare Earth Ion-Doped Monoclinic Yttrium Sesquioxide.

Monoclinic Y2O3 phosphors doped with Eu3+ or Pr3+ are obtained for the first time by treatments in inductively-coupled thermal plasma. This paper reports the luminescence properties of these phosphor materials. The assumption proposed earlier by the authors, that the emitting levels of Pr3+ in Gd2O3 are determined by the distance between the Pr3+ ion and the surrounding oxygen ligands, is found consistent even when the monoclinic Y2O3:Pr and other oxides are included.

White Light-Emitting Diodes for Wide-Color-Gamut Backlight Using Green-Emitting Sr-Sialon Phosphor

We have successfully developed a white light-emitting diode (LED) for a wide-color-gamut backlight composed of a green-emitting phosphor Sr3Si13Al3O2N21:Eu2+ combined with a blue LED and a red-emitting phosphor CaAlSiN3:Eu2+. This white LED showed a discrete spectrum with distinct separation of red, green, and blue primary colors due to a narrow emission band of around 525 nm for the green phosphor. 94.2% of the wide color gamut of the National Television System Committee standard was attained by applying typical color filters of LCDs. The power LED module composed of 16 of these white LEDs revealed their excellent power dependence. The LED is expected to replace cold cathode fluorescent lamp (CCFL), and find a suitable application as a backlight in large-scale LCDs for in-vehicle use or for flat-panel television sets.

Preparation of spherical phosphors by thermal‐plasma treatment

Garnet-structured rare-earth oxysulfide and zinc sulfide phosphors were treated by thermal plasma in order to obtain spherically shaped phosphor particles. Although spherical particles of garnet phosphor and rare-earth oxysulfide phosphor were obtained, their luminescence properties were lowered. However, the properties could be partially restored by optimized heat treatment.

Synthesis and Characterization of β-SiAlON Phosphor Powder Prepared by Reduction Nitridation of a Zeolite

Rare-earth activated oxynitride or nitride luminescent materials have attracted considerable attention due to their potential applications as phosphors and pigments. Eu2+-doped -sialon has been reported to represent a new class of green phosphors with high efficiency. In this study, -sialon phosphor was synthesized by reduction nitridation of a zeolite. Eu ion-exchanged zeolite was fired at 1400 °C for 1 hour under NH3 gas containing 0.5 vol%C3H8. As a result, formation of -sialon with green emission under UV irradiation was confirmed.

30.3: Reduction of Electron‐Beam‐Induced Degradation of ZnS Green Phosphor Coated with Phosphate

Electron-beam-induced luminescence degradation is found to be reduced in ZnS: Cu, Al phosphor coated with a limited low content of phosphate. The behavior of the degradation is correlated with the quantities of SO2 and H2O gases released from the phosphors, analyzed by temperature programmed desorption-mass spectrometry (TPD-MS) and transmission electron microscopy (TEM) observations. We find that the layer coated with the appropriate phosphate content is uniform and continuous, which prevents the surface chemical reactions that cause the degradation.