Research On The Technology For Quantum Efficiency Measurement Of Luminescence Glasses For White LED

Now，the combination of blue LED chip and wavelength-converter YAG phosphoris used in most practical white LEDs. However, the phosphors have some problemssuch as poor thermal stability, color coordinate prone to drift and low extractionefficiency. For the past few years, luminescence glasses is applied to the white LED hasbeen extensively studied, it has obvious advantages compared phosphor in thermalstability, sample size, experimental methods and equipment, and other respects, Itprovides a new structure for high-power white LED. The quantum efficiency is a majorparameter of luminescent materials which can characterize the ability of excitationenergy converted to luminous energy. Accurate measurement of the quantum efficiencycan evaluate the luminescent properties of the luminescent glasses, which provides animportant basis for quality improvement of the luminescent material. Therefore, wemade the following work which was aimed at the measurement of the quantumefficiency:The first chapter elaborated the significance of this study, analyzed the status quo athome and abroad at the measurement of the quantum efficiency for fluorescencematerial, and introduced the purpose and research content of this paper.In the second chapter, we introduced the definition of quantum efficiency, andprovided the preparation technology of the luminescent glasses. On the basis of thepredecessors’ research in the measurement of quantum efficiency for solid fluorescencematerial, we combined with the characteristics of measured fluorescence glass, andprovided the measurement scheme and measurement principle of the quantumefficiency based on integrating sphere.In the third chapter, the experimental device for the measurement of quantumefficiency was provided. The experimental system included four key parts, which werethe selection of test light source, the design of the integrating sphere, the design ofsample special fixture and the choice of the grating spectrometer. Various componentsplay different key role in the measurement of quantum efficiency. In this paper, theselection and design of every part was researched more detailed.In the fourth chapter, according to the measurement scheme, the experimentalsystem was set up, and the luminescence glasses were fabricated by high temperaturemelting technique and MgAl2O4fluorescence transparent ceramic were test by this experimental system. Accurate measurement of the quantum efficiency can evaluate theluminescent properties of the luminescent glasses, which provides an important basisfor quality improvement of the luminescent material.In the fifth chapter, the factors influencing the accuracy of the measurement ofquantum efficiency were analyzed; it was mainly integrating sphere, light source andthe spectrometer. In addition, experiments were designed to study the influence of theluminous flux of light source and the size of light spot on quantum efficiencyIn the sixth chapter, the studies of article were summarized, pointed out theproblems to be further addressed, and the development proposals were put forward.