Freeform Optical And Control System For LED Array

High power light-emitting diodes (LEDs), with increasing luminous efficiency and cost performance in recent years, have more and more applications in lighting. Due to small luminous flux of single LED chip, it is a tendency to use multi-chip package to enhance luminous flux. However, LED chip array will lead to large light-emitting area which can not be treated as point source. And this is a great difficulty for LED optical system design. To overcome the drawbacks of controllable radiation pattern (RP) and optimization method of LED array lighting, this dissertation mainly focuses on the research of freeform optics design and arrangement plan for LEDs array. Based on these methods, multifarious novel freefrom lens are designed to increase the optical efficiency and to form controllable beam pattern. Achievements are presented below.For the illuminance distribution of LED chips array with small spacing, we propose a novel freeform lens algorithm based on optimizing the division of target grids for uniform illumination, which provides the illuminance information and adjusts the energy mapping. Based on this method, we develop a non-symmetry optimization method. It has more flexible light energy mapping relationship than symmetry method. Based on these two methods, we design two novel road lighting modules with LED chip array source, which can provide both high illuminance/luminance uniformity and glare control.For the light intensity distribution of LED chip array with small spacing, we propose a circle-symmetry freeform lens algorithm based on reversing fitting design method for extended source, which collects and feeds back the light intensity distribution information and reversing optimize freeform surface of lens. It can quantificationally correct light intensity distribution error which are created by the extended source. As an example, aeronautical ground optical system is designed with this method, which can meet the requirements of ICAO very well.For the arrangement plan of LED array with large spacing, we propose two auto-optimization algorithms based on Illuminated area Expending and Sub-regions Compensating methodologies for uniform illumination, which input initial values of lamp and optimize arrangment of LED array. As an example, aeronautical ground optical system is designed with this method, which can meet the requirements of ICAO very well. In the practical application, we get a high uniformity of illumination distribution (0.6) with less LED modules.For the optical system design of LED array with large spacing, we propose a ray control method based on collimation and beam expender optical system for extended source, which uses micro-freefrom array lens or flim to control the collimated rays emitted from LED array. We can get a variety of radiation patterns by overlaying or removing lens. At the same time, we develop a milti-channel control system for LED stage lamp, which can form full variety colours. Its colour range is larger than the traditional lamps and more extreme colours can be created.