Design of highly efficient white led for the maximal cri

Abstract

Phosphor-converted white light emitting diodes (pc-LEDs) are being used as a source of artificial lighting. One of the main goals of artificial lighting is to make objects/images look natural – as they look under the sunlight. The ability of a light source to accurately render the natural color of an object is gauged by the color rendering index (CRI) and a conventional pc-LED has an average CRI– CRI Ra ~ 80 which is not suitable for artificial lighting. In order to fabricate the pc-LEDs for artificial lighting applications, all the CRI points (R1 – R15 ) should be above 95. Herein a novel design strategy of an LED package (PKG) is implemented to achieve CRI points ≥ 95 through introducing two blue LEDs and a UV LED in combination with green and red phosphors. The silicone encapsulant, the ratio of the current through the LEDs, and the phosphor ratio were optimized for achieving high efficiency (~ 100 lm/W) as well as all the CRI points above 95. Our re-designed LED PKG with an efficiency of around 100 lm/W would find applications in stadium lighting as well as for ultra-high definition television production where high CRI points are required for the light source.