Chip scale optics developed for GaN-on-Si LEDs

The first off applications include retail spot lighting, hospitality lighting, high and low bays, street lighting and stadium lighting.  It is estimated that Plessey's chip scale optics will halve the cost of these lighting applications.

Dr. Keith Strickland, CTO, Plessey, commented: "The CSO technology was originally designed as an on-chip phosphor dam. We realised that the original growth silicon, normally sacrificed during LED production, could be shaped and used to form mechanically robust, MEMS-type features on the emitting surface of a vertical LED. The degree of collimation is controlled in part by the mechanical dimensions of these on chip structures and we have demonstrated emission angles as low as 10°. The IC industry has used silicon for over 60 years and can be readily fashioned into many shapes and patterns. We have created silicon MEMS features in a variety of other applications and can manage to incorporate a complex primary optical design on the chip."

"High-end lighting designers do not count lumens per Watt as the primary figure of merit for LEDs. A lighting designer aims to illuminate a particular surface area. CSOs can significantly simplify luminaire designs by forming symmetrically collimated beams with narrow angles or asymmetric beams to form elongated far field light profiles. Schemes to collimate monochromatic light at the LED level have been developed before but no-one has previously collimated white light at the LED level," added Dr. Samir Mezouari, Principal Optical Designer, Plessey.

Plessey will be exhibiting an LED demonstrator of the CSO at LuxLive, the UK's largest lighting show, in November 2015. Samples will be available in Q1 2016.