同動射出壓縮雙面微透鏡陣列製程開發

Co-Injection Compression Molding of Double-sided Microlens Array

陳建銘(Jian-Ming Chen)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602293

摘要

射出壓縮相較於一般射出成型，可以降低射出壓力，受壓均勻，內應力小; 用於光學元件製造，可以提高透鏡轉寫率，且降低殘留應力，提升光學品質。本研究利用同動射出壓縮成型製作聚碳酸酯雙面微透鏡陣列。
實驗首先以Moldex3D模流分析軟體分析雙面微透鏡陣列同動壓縮成型，並以田口實驗設計L9表，模擬九組不同壓縮速度、壓縮間距、模具溫度、及開始壓縮點參數組合的同動射出壓縮成型，探討其對雙面微透鏡陣列成品品質影響，並尋找最佳參數組合。結果顯示壓縮速度、模具溫度為精確成型微透鏡陣列高度與直徑之最重要因子。本研究並實際開發模具，以實驗探討同樣九組參數組合的同動射出壓縮，製造雙面微透鏡陣列，發現用最佳參數組合進行同動射出壓縮比ㄧ般其他條件之射出與射出壓縮，有較佳的均勻性、轉寫率、透鏡間距與低殘留應力，其凸透鏡與凹透鏡的平均直徑轉寫率達96.3 %，高度轉寫率為98.15 %。
本研究再進一步檢測雙面微透鏡之光學性質，分別量測觀察雙面微透鏡之有效焦距(EFL)、光斑直徑(Spot Size)。平均有效焦長為1.5228 mm，標準差只有0.0152 mm。另外，1.2 mm直徑的光源經聚焦，具平均光斑直徑大小約為50 μm。本研究證實同動射出壓縮可成功製作雙面微透鏡陣列。

關鍵字

雙面微透鏡 ； 短射射出壓縮成型 ； 田口法

並列摘要

This study is devoted to the co-injection compression molding of polycarbonate double-sided microlens array. Compared with the conventional injection molding, the pressure of injection compression molding can be reduced. The uniform compression pressure over the whole projection area can improve the transcription rate. In addition, the residual stress in the product can be lowered, and the optical quality can be improved .
First, the co-injection compression molding process was simulated with Moldex3D software. The experimental design using L_9 table of Taguchi method was used. The effects of four molding parameters, including the compression speed, compression stroke, mold temperature, and starting point of compression were investigated. It was found that the compression speed and mold temperature are the most significant parameters as far as the precision of diameter and height of microlens are concerned. The optimal combination of processing parameters was identified. Furthermore, a mold for co-injection compression of double-sided microlens array was designed and constructed. Co-injection compression moldings were performed using the same combinations of process parameters used in simulation. The dimensional quality of the co-injection compression molding shows the same trend as the simulation. The quality of co-injection compression molded microlens array using the optimal combination of process parameters is better than what obtained using other combination of process parameters. The transcription rate of microlens diameter is 96.3 % for the convex and concave surface of microlens, while the transcription rate of microlens height is 98.15 %. In addition, the residual stress of the molded microlens array was comparatively lower than those molded with conventional injection molding process.
The optical properties, including the effective focal length (EFL) and spot size, of the injection compression molded microlens were further characterized. The average EFL was 1.5228 mm with a standard deviation of 0.0152 mm. The average spot size of the original light source of 1.2 mm diameter was focused to 50 μm diameter. The co-injection molding process can fabricate uniform precise microlens array. This research proves the potential and capability of co-injection compression molding process for the fabrication of double-sided microlens array.

並列關鍵字

Double-sided microlens ； Injection compression molding ； Taguchi method

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