The Investigation of Reliability of White Light Emitting Diode with Different Types of Phosphors

• Main Authors: Mei-Hui Wu, 吳美惠
• Other Authors: 謝振榆
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/e47x4j

碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 100 === It has been a common view to work on energy efficiency and carbon reduction while facing the issue of energy supply shortage and excess carbon emission. In response to the worse problem of global energy shortage and carbon emission, everyone should take some actions of energy efficiency and of carbon emission reducing. The advantages of LED are quick response, small size, energy saving, electricity saving, low pollution and could be made in mass production. Besides, the LED can be easily assembled on small components, which solved the formidable issue of white bulb applied in the past. It is the new lighting choice including environment protection and electricity saving. There are four types of phosphor. YAG (Y3Al5O12), TAG (Tb3Al5O12), Silicate, Oxy-nitride respectively. We use equipments to analyze the specialty of the phosphor. That is including some information photoluminescence (PL), scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDX), Beckman Coulter Multisizer. We have chosen as one package size, then checked it before reliability test and collected the first data of luminous flux by integrating sphere. We can set difference temperature and humidity conditions of reliability test. And then collected the data luminous flux, value (X,Y), decay state etc after reliability test. We can compare difference phosphor and reliability of LED. For YAG, the half band width of its spectrum is the widest. After being packaged, the CRI is better, which is more suitable for lighting products. As for Silicate, the half band width of its spectrum is narrower, which can be used for backlighting products that CRI will not be taken into consideration. The wave pattern is narrower; the distribution of the particle size will be more centralized. Namely, after being packaged, the main production delivery distribution will be more focused, which means the possibility to produce within spec products would be much higher. For both Silicate and Oxy-nitride, Sr is one of the elements contained. Since this element is sensitive to humidity and temperature, it would be better to use these two kinds of phosphor in backlighting products. For the relationship among package reliability, phosphor’s surface, particle size, and composed elements, more studies would be necessary.