A ceramic phosphor is a solid element composed of a high density color converter made using powder phosphors and functional materials. Conventional LEDs use phosphor powders encapsulated in polymers as color converters. Compared to polymer-encapsulated phosphors, ceramic phosphor plates generally show superior properties with regards to thermal stability, long-term degradation and CIE color coordinate changes. Solid ceramic phosphors can avoid many of the high power density limitations but can have limitations in terms of light extraction and blue light absorption.
Phosphor in Glass (PiG) can overcome the blue absorption and light extraction limitations by suspending phosphor powders in a transparent glass matrix. PiG converters can still deliver superior thermal performance compared to polymer-based systems. This can lead to improved efficacy and color stability of the phosphor-converted LED (pcLED) or laser-excited phosphor (LEP) device.
A ceramic phosphor converter can be combined with a blue (or UV) laser and/or high power LED to generate high color rendition white light. In addition, many saturated (red, green, etc.) colors can also be produced using PiG components combined with blue or UV sources.
Ceramic Phosphor Plate Converters can Enhance the Thermal and Optical Stability of High Power LEDs