LED-BASED ILLUMINATION MODULES WITH THIN COLOR CONVERTING LAYERS
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
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.