Lens for improved color mixing and beam control of an led light source

Abstract

A multi-color LED illumination device and specifically a lens comprising a cylindrical opening extending into the lens from a light entry region at which one or more LEDs are configured. A concave spherical surface extends across the entirety of the light exit region of the lens, and a TIR outer surface shaped as a CPC extends between the light entry region and the light exit region. There are various diffusion surfaces placed on the sidewall surface of the cylindrical opening, as well as its upper planar surface and, depending on whether glare control is not needed, the exit surface of the lens. Lunes can also be configured on the sidewall surfaces of the cylindrical opening and if lessening glare is needed, also on the TIR outer reflective surface. The combination of lunes, diffusion elements, and the overall configuration of the lens provides improved color mixing and output brightness according to one embodiment. According to another embodiment, diffusion elements are manufactured and possibly increased on only select surfaces but not on the light exit region in order to lessen glare. Three light interactions in a first portion of light and two interactions in a second portion of light can improve color mixing and beam control. Those interactions includes two refractions either with an intermediate reflection or not, all of which are necessary to achieve the improved performance of the multi-color LED illumination device and lens hereof.