Led-based illumination modules with thin color converting layers

Abstract

An illumination module includes a plurality of Light Emitting Diodes (LEDs). The illumination module may include a reflective color converting element with a PTFE layer and a color converting layer fixed to the PTFE layer. The color converting layer includes phosphor particles embedded in a polymer matrix and has a thickness that is less than five times an average diameter of the phosphor particles. The illumination module may include a transmissive color converting element. The color converting elements may be produced by mixing a polymer binder with a solvent and phosphor particles to form a homogeneous suspension of the phosphor particles. The homogeneous suspension is applied to a surface to form an uncured color converting layer, which is heated to vaporize the solvent. The cured color converting layer includes the phosphor particles suspended in the polymer binder

What is claimed is: 
     
         1 . A method comprising:
 mixing a polymer binder with a solvent and a plurality of phosphor particles to form a homogeneous suspension of the phosphor particles;   applying the homogeneous suspension to a surface of a transparent substrate to form an uncured color converting layer; and   heating the uncured color converting layer to vaporize the solvent to form a cured color converting layer, wherein the cured color converting layer includes the phosphor particles suspended in the polymer binder, and wherein a thickness of the cured color converting layer on the transparent substrate is less than five times an average diameter of the phosphor particles.