New paradigm of multi-chip white LEDs: combination of an InGaN blue LED and full down-converted phosphor-converted LEDs

This study introduces innovative multi-chip white LED systems that combine an InGaN blue LED and green/red or green/amber/red full down-converted, phosphor-conversion LEDs (pc-LEDs). Efficient green, amber, and red full down-converted pc-LEDs were fabricated by simply capping a long-wave pass filter (LWPF) on top of LED packing associated with each corresponding powder phosphor. The principal advantage of this type of color-mixing approach in newly developed multi-chip white LEDs based on colored pc-LEDs is thought to be dynamic control of the chromaticity and better light quality. In addition, the color-mixing approach improves the low efficacy of green/amber LEDs in the "green gap" wavelength; reduces the wide color/efficacy variations of each primary LED with at different temperatures and currents; and improves the low color rendering indexes of the traditional color-mixing approach in red, green, and blue (RGB) multi-chip white LEDs.