Rapid prototyping of freeform optics for an LED downlighter with a dynamically adjustable beam

In this paper, an LED downlight producing dynamic beam variation without any mechanically moving parts is presented. The functionality is based on an optics design using compound parabolic concentrators equipped with individual LEDs. With suitable driving of the LEDs, a dynamic far-field beam with an adjustment range of between 16° and 55° is achieved. The luminaire is used as a demonstration of the polyurethane vacuum casting rapid manufacturing method to produce low-cost freeform optics for prototypes. The simulations and measurements on the realized prototype show that the method is suitable for small series and prototype manufacturing, but also reveal potential errors in the rapid manufacturing process to be avoided in the future.