The influence of K2O/R2O (R2O=Na2O+K2O) on some characteristics of color conversion glass were studied using a BaOZnO- B2O3-SiO2 glass. One reference glass, comprised of 40 mol% of BaO and 20 mol% of the other three components, was used, and 5 wt% of an alkali oxide was added to the other five glass samples. The ratio of the alkali oxides used were K2O/ R2O (where R2O=Na2O+K2O) 0, 0.25, 0.5, 0.75, and 1. Six color conversion glass samples were prepared by sintering a mixture of glass frits and a YAG phosphor. The content of the YAG phosphor was maintained at 5 wt%. The characteristics of the color conversion glasses, with respect to luminous efficacy, CIE (Commission International de I'Eclairage) chromaticity, CCT (Correlated Color Temperature), and CRI (Color Rendering Index) were analyzed based on PL spectra. The luminescence properties of the color conversion glass with K2O/R2O = 0.5 were nearly identical to those for the reference glass even though it contained 5 wt% alkali oxides.

Keywords: Mixed alkali effect, Color conversion glass, Glass composition, YAG phosphor.