Research On LED Remote Phosphor Lighting System

As the next generation luminaires, light emitting diodes(LEDs) demonstrate some pronounced advantages such as high luminous efficiency, compact size, energy saving and environmentally friendly features. And LED lighting has become a main development direction of the future lighting technology. Remote phoshpor(RP), which further improves the efficiency and reliability of LED products, has shown a bright market prospect. Meanwhile, RP can be designed into arbitary geometry, which provides unprecedented flexibility and creativity for the LED products. However, researches on the manufracturing process and optical-chromatic characteristics of RP used in LED lamps have been rarely reported to the best knowledge of the author. This paper applies the spin coating process to manufacture the RP layer and investigates the influcence of the RP positions on the optical-chromatic-thermal performance of the LED lighting system. And then an RP LED down lamp is developed and tested. The main research contents are as follows:(1) Manufacturing of RP using spin coating process.The rheological characteristic of the phosphor colloid is investigated. And then the spin coating kinetic model of the phosphor colloid is built up. The influence of the spin coating process parameters on the film forming of the phosphor colloid is theoretically analyzed. And also experiments are performed to reveal the influencing mechanism of the spin coating revolving speed and time on the final thickness of the phosphor colloid film.(2) Investigation on the influence of the RP positions on the light quality and thermal performance of the LED lighting system.By changing the distance between the RP and the LED light source, the optical power, luminous flux and correlated color temperature(CCT) are measured to investigate how the RP positions influence the optical-chromatic properties of the LED lighting. The self-heating of the RP layer is investigated. The influence of the RP positions on the thermal performance of the LED lighting system is investigated. Additionally, this paper also performs accelerated aging test to investigate how the optical-chromatic properties of the RP change with the aging time.(3) Development of the LED lighting system.An LED down lamp is developed by comprehensively considering how the RP positions influence the optical-chromatic-thermal performance of the LED lighting system. By selecting proper kinds of phoshpr and phoshpr concentration, the RPs with high color rendering index(CRI) and different CCT are developed. The driving power supply of the LED down lamp is developed and manufactured by adopting switch-mode power supply scheme, of which the electronic components are selected by theoretical calculation. Finally, the optical-chromatic-thermal characteristics of the LED RP down lamp are measuerd and analyzed.