Research On The Optical Design Method Of The Lens Free Surface On Extended Illuminant

LED with COB package has great advantages such as compact structure,large light flux,etc.,so it has been increasingly widely used in the lighting area,especially in outdoor lighting,large space lighting and other lighting application.But because of the COB light source's scale is more than ten times compared to traditional high-power LED light source,if it is still regarded as traditional point source and design with secondary optical system,the design results will have a great error.Particularly it very hard in the optical system to meet both indicators: compact size and small angle.The paper is mainly study the characteristics of extend source,depend on the macro-size LED with COB package,raise a digital totally method to design a free-surface to make the exit angle smaller for extend source.At first,the paper will introduce the fundamental theory of extend source,and the preserve the concept of nonimaging optics derive from the imaging optics.Then introduce the general method in nonimaging optics,mainly divide into these parts:1.Study on the characteristics of extend source,list different methods to divide the extend source into infinitesimal pieces,get the parameters which can describe the mini-piece feature.2.Study on the method to rebuild the free-surface,and analyze light distribution feature of traditional design method for two-dimensional extend source,include the method with flat mirror.3.Study on a method of highest energy based on stretch curving surface and apply to the design of extend source with programming.4.With the method raised,lens with free-surface will be designed to decrease the exit angle,minimize the lens scale simultaneously.