Optical system design method for the concentration of radiation from a high-power LED

An optical system is considered that ensures the concentration of radiation from an LED emitting within a hemisphere onto a near-field illuminated area. The system is proposed to consider such a system as a composition of two zones — the central zone, which is a lens, and the zone responsible for capturing radiation from the LED within an angle of 40 to 90 degrees. Variants with a central zone in the form of bi-aspherical and sphero-elliptical lenses of finite thickness are analyzed. The alternative variant of the concentrating system composed from a collimating TIR lens and additional focusing lens is also analyzed. The expressions are given that allow analyzing possible concentration efficiency and the light spot size, and examples of systems are given designed with taking into account theoretical analysis results. Factors are discussed that define the choice of the required configuration. The results have shown the good agreement between the theoretical approach and practical design results. The optical elements designed as examples showed the high optical efficiency (near 90 %), thus such approach can be used for designing the LED optical systems for efficient light flux concentration, for example operating with fiber bundle as needed in some optical — electronic devices.