Effect of Reassembled Remote Phosphor Geometry on the Luminous Efficiency and Spectra of White Light-Emitting Diodes With Excellent Color Rendering Property

Abstract

This paper presents a scattered photon extraction (SPE) structure with a reassembled remote phosphor layer. The reassembled remote phosphor layer of the SPE structure was fabricated by combining green and red phosphor pieces with varying phosphor geometries, reducing the reabsorption of green emission by the red phosphor. The experimental results revealed that the SPE structure light-emitting diodes (LEDs) with the green and red phosphors in the remote phosphor layer demonstrated a high color rendering property. Moreover, with the same green and red phosphor weights and ratio in the remote phosphor layers, the output power and the luminous flux of the SPE structure LED with a reassembled remote phosphor layer were higher than those of SPE structure LEDs with mixed remote phosphor layers. The reduction in the reabsorption of green emission by red phosphor in the SPE structure with the reassembled remote phosphor layer was responsible for the high output power, and indicated a high correlated color temperature of the SPE structure with the reassembled remote phosphor layer. It was also found that the green emission with corresponding output power of the SPE structure LED containing the reassembled remote phosphor layer decreased with an increase in the piece number.