Research On Measurement Technology Of Luminescence Performance Of Fluorescent Materials For LED

With the rapid development of energy-saving lighting industry,the white light LED as the representative of the new solid-state lighting,because of its energy-saving,environmental protection and long life,quickly became the fourth generation of lighting source.At present,the white LED is made of a fluorescent material with a blue or ultraviolet LED chip,and its luminescent performance is mainly measured through a series of parameters of a fluorescent material,especially represented by quantum efficiency.Based on this,this thesis designs a LED fluorescent material luminescence performance measurement system.The following is the specific work done for this measurement system:Based on the content and purpose of the study,we designed the overall diagram of this measurement system,including the following modules,the selection module of lighting source,the light collection module of integrating sphere,the optical fiber detection module and the collection and processing module of spectral information.Based on the optical fiber detection technology,in order to prevent the primary light from directly entering the optical fiber detector,we set three different detection angles respectively,and compared the light intensity received at different angles,and at last,we selected the angle at which the maximum light intensity is received as the detection angle.Because of the different size of the integrating sphere,the detected light intensity is different,so we simulated eight integrating sphere with different diameters respectively,such as 30mm,50mm,60mm,80mm,100mm,150mm,200mm and 300mm.And through detecting light intensity in each size with compared the difference,we selected the diameter of 100mm integrating sphere as a light collection device.Due to the existence of the sample fixture and the weak detection signal,we contrasted the effect of the total-integrating sphere and the semi-integrating sphere on the detection light intensity.The theoretical derivation and the experimental simulation are used to compare the two methods.The final selection is based on half Integrating sphere measuring system.Based on the size of the semi-integrating sphere and LED chip,we designed the size of the plane mirror and its inner center hole and designed the collocations of the plane mirror,the light source and the fluorescent sample according to the three-step measurement.After collecting and post-processing the detected spectral data,we measured the quantum efficiencies of three different YAG phosphors,red phosphors and fluorescent quantum dots and analyzed the results.