Study on Injection Molding of a Fresnel Type Lens for Cell Phone Flash Light

• Main Authors: Yuan-Bin Tsai, 蔡元斌
• Other Authors: Min-Wen Wang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/56586733828057483735

碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 98 === As technology advances, there are more and more extensive application of optical elements, of which Fresnel lens is one of the representative products, mainly is the use of micro-structure to change the light path. Compared with the conventional convex lens, lighter is it’s advantage .Most of the present Fresnel lens are for solar concentrator systems, to collect and concentrate light to a small area, increasing the light usage. This study aims to examine the optical characteristics of Fresnel lens, to apply on camera flash light of mobile phones. Today, in order to reduce its power consumption ,mobile flash light switch from the helium flash to LED as substation, but the LED general lighting angle is too wide, so that part of the light falls outside the scope of photography, resulting in limited performance and efficiency. Thus, by characteristics of the Fresnel lens, to adjust the angle of the light irradiation to improve lightening efficiency. The primary object of this study set out with a Fresnel lens ,of which diameter is 5.5mm,By using optical design software TracePro, to design its optical micro-structure, so that large emission angle of LED light source falls within ± 30 ° angle, and to strengthen to 2.4 times in the axis direction. In mold design process, using Moldex3D software to do mold flow analysis helping with mold design ,looking out for best gating design and molding parameters, In the injection molding process, by trial and error method to find shape window, then using Taguchi method to study the influences ,plastic forming parameters of temperature, mold temperature, injection speed and holding pressure process parameters on the forming quality of a Fresnel lens. The experimental results show that holding pressure is the important factor affecting the optical quality ,by the best parameters measured and light distribution curve, the results obtained were compared with analysis of the angle error is less than 2%.