Quasi-conformal phosphor dispensing on LED for white light illumination

This paper introduces the development of an innovative conformal phosphor deposition method. Several existing conformal phosphor deposition methods are compared and discussed first. Afterwards, a new “quasi-conformal phosphor dispensing” method is proposed. This method uses conventional dispersed phosphor dispensing equipment without any modification. The only requirements are the control of phosphor concentration/volume and the mounting of an additional platform underneath the LED chip. In this paper, the packaging structure and the implementing procedure of the quasi-conformal phosphor dispensing method are demonstrated in detail. In addition, the optical performance of prototypes is characterized and compared to that of matching conventional packages. Furthermore, the impact on production cost is also discussed. Compared with the conventional dispersed phosphor deposition method, more than 50% of phosphor saving could be achieved with the proposed new method. Such a saving is considered essential for the cost reduction in LED manufacturing.