Tunable illumination for LED-based systems using refractive freeform arrays

Abstract

Tunable illumination with high uniformity can improve functionality for multiple application areas. In lighting applications, dynamic illumination has been achieved by applying axial movement to the source(s) or other optical elements, resulting in poor uniformity, or using a liquid lens that adds design complexity. Advances in high-precision manufacturing methods have facilitated the practical implementation of freeform optical components, enabling new design approaches for illumination systems. This paper explores the use of arrays of varifocal transmissive freeform Alvarez lenses for an LED-based illumination system. The design is initialized using paraxial geometrical optics concepts and then refined for a 1mm-by−1 mm white LED source through a multi-step optimization. Design procedures are discussed, and simulation results are presented for an example illumination system that varies from a small circular spot mode to a large square uniform flood mode through millimeter-scale lateral translation between the Alvarez lens arrays.

A Compact Two-Dimensional Varifocal Scanning Imaging Device Actuated by Artificial Muscle Material

“…A compact two-dimensional varifocal scanning imaging system, which exhibits the ability to provide detailed object information and adjust the interesting area to make the object centered in the field of view, plays a crucial role in the fields of robots, aerospace, and biomedicine, etc. [ 1 , 2 , 3 , 4 ].…”

The Light Features and Bredigite Layout for Orthosilicate Phosphor in WLED Devices

“…If the ions merge with the CMS crystal layout, they could replace every cation location which includes Ca 2+ , Mg 2+ , and Si 4+ . On the other hand, with the ion radius and the permitted value of oxygen coordination (n) taken into account, Ca 2+ (1.12 Å, n value of 8), Mg 2+ (0.72 Å, n value of 6) and Si 4+ (0.26 Å, n value of 4), replacing the ions of Mg 2+ as well as Si 4+ with those of Eu 2+ (1.25 Å, n value of 8) would be a challenging task (Shadalou, Cassarly, and Suleski, 2021;Shi et al, 2021).…”