Plessey says it has developed a patented technology for chip scale optics (CSO) based on its GaN on silicon MaGIC LEDs. According to the company, CSO permits the design of light emission angles as low as 10° directly from the LED, reduces cost and brings more design freedom for secondary optics.
Dr Keith Strickland, Plessey’s CTO, said: “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°. 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.”
According to Dr Samir Mezouari, the company’s principal optical designer, lighting designers aim to illuminate a particular surface area. “CSO can simplify luminaire designs by forming symmetrically collimated beams with narrow angles or asymmetric beams to form elongated far field light profiles. While schemes to collimate monochromatic light at the LED level have been developed before, nobody has collimated white light at the LED level.”
