Optical properties of phosphor-in-glass through modification of pore properties for LED packaging

• Published in: Optical materials 2018-01, Vol.75, p.814-820
• Main Authors: Kim, Sunil, Kim, Hyungsun
• Format: Article
• Language: English
• Subjects: Glass frit size; LED; Optical properties; Phosphor-in-Glass; Pore properties
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2017.12.003

The volume and size of the voids present between the frit and the phosphor particles used before sintering determine the pore properties of the resulting phosphor-in-glass (PIG). The pores formed from the voids influence the path of the incident light, thus changing the optical properties of the PIG. Therefore, the trends observed for the shrinkage and the green and sintered densities of the PIG were investigated using SiO2-B2O3-ZnO-K2O glass frit of four sizes to understand the tendency for the pore size, porosity, and optical properties of PIG. It has been demonstrated that variation in the pore properties according to the particle size influences parameters defining the light scattering phenomenon, such as the scattering angle of the light and the scattering coefficient, as well as the color rendering index, correlated color temperature, and package efficacy. The results obtained for the variation in the optical properties with the frit size can be used as a reference to select the appropriate glass frit size to achieve the required optical properties for a light-emitting diode (LED) package. •The effect of the glass frit size on the microstructure and optical properties of the phosphor-in-glass (PIG) is proposed.•A change in the size of the glass frit causes a change in pore properties of the PIG.•The optical properties of the PIG depend on the variation in pore properties.•The luminous efficacy of the LED package can be improved by controlling pore size of the PIG.