Analysis on Light Transmission and Thermal Conductivity of Functional Secondary Optical Elements by Injection Molding of PMMA-TiO2 Composites

• Main Authors: Peter Jonathan, 陳嶒永
• Other Authors: Chao-Chang Arthur Chen
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/22050690562418326526

碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === This study aims to investigate the dominant wavelength shifting and thermal conductivity effects of titanium dioxides (TiO2) nanoparticles in Poly(methyl methacrylate) matrix of Total Internal Reflective (TIR) – Fresnel Lens for LED illumination application. PMMA-TiO2 composites has been mixed using twin screw extruder. Then, Thermogravity Analysis (TGA) and Difference Scanning Calorimetry (DSC) are used to obtain the maximum melted temperature (Tmelt) and glass transition (Tg) temperature of PMMA-TiO2 composites, respectively. The mold design of TIR-Fresnel lens is simulated by Moldex3Dc software and the lens is manufactured by injection molding process. Warpage measurement, illumination testing, and integrating sphere are conducted to obtain the appropriate injection parameters of injection molding, including packing pressure about 63 MPa and injection speed around 3 mm/s. This TiO2 has been modified to adapt for white light spectrum and used to absorb the blue light significantly and green light moderately. Moreover, the uniform output can achieve through the TIR-Fresnel lens of LED lighting. Illumination testing shows that as the TiO2 concentration increases, the light intensity drops. PMMA-0.01% TiO2 is the best composition with performance of 42 lux and 7.99° projection angle. In this study, the illumination testing results have been verified by integrating sphere test to observe the dominant wavelength shifting with white and blue LED. The UV-Vis measurement is also conducted to have fundamental result of light transmittance out of flat panel lens. It shows that the higher TiO2 concentration absorbs the blue and green light which cause the light shift the wavelength. Last but not the least, thermal conductivity test is also conducted to investigate the effect of TiO2 on TIR-Fresnel lens application. It shows that as the concentration of TiO2 on PMMA increases, the thermal conductivity increases from 5.6% up to 13% as the composition 0.01% - 0.1% of TiO2. For both optical and thermal purposes, the PMMA-0.01% TiO2 is the suggested composition with increasing thermal conductivity by 5.6% and reducing working temperature by 3.65%. Results of this study can be applied in LED illumination for better performance and also reducing the blue light concentration.