Single Crystal Phosphor Material

Light-emitting diodes are used with fluorescent materials to produce different color lights. Among them, blue LEDs and yellow Ce:YAG powder are mixed to produce white light which is the most widely used lighting application. As the demand for increasing lighting brightness , in addition to the continuous increase in wattage per LED chip, the brightness is also improved through the combination of LED chip arrays. There comes a problem at high temperature and leads to thermal quenching for fluorescent material. As a result, the quantum conversion efficiency decreased and most of the input power is converted into heat. Later, in order to solve the problem of thermal quenching, there were the development of materials such as phosphor in glass (PIG) and phosphor in ceramics (PIC), but the conversion efficiency was still inferior to single crystal phosphor (SCP) materials at high temperatures (Figure 1)

(Figure 1)

In practice, if the thickness of the SCP is too thin, the blue ray easily penetrates and the white light after mixing tends to cold white. To produce a sufficient yellow light, the thickness of the SCP must be thickened, so that the increase in the volume of the crystal is not conducive to the existing optical design. Therefore, how to increase the optical path of blue ray in the crystal to increase the absorption of blue ray and convert more yellow light which has become a major challenge for the development of fluorescent crystal materials.