UV噴墨印刷製作微透鏡陣列之研究

Abstract

現今折射型微透鏡陣列發展進度仍受侷限，主因是製程繁瑣、成本高昂和提供規格有限，且被動式的搭配無法獨樹一格，所衍生產品規格雷同相似。本研究將以UV噴印透明墨水方式印製折射型微透鏡陣列，自選材料厚度，控制透鏡大小、間距、透鏡高度等以控制微透鏡的成像條件，則將大幅突破折射型微透鏡陣列規格限制，進而改變現有製程，突破困境。 本研究利用疊紋放大原理，設計不同大小透鏡陣列檔案，再以UV噴印透明墨水形成微透鏡結構在不同厚度透明片材上，使1951 USAF 解像力測試圖可供鑑別，以獲得UV噴印折射型微透鏡陣列結構的分辨力數值，作為初級判斷微透鏡陣列優劣方式；其次，再測量微透鏡之調變轉換函數（Modulation Transfer Function，MTF）和曲度輪廓參數（Profile），為進階評判微透鏡成像結果研究，以分析其微透鏡成像品質特性。 經研究結果證明，以UV噴印透明墨製作微透鏡陣列使用是可行的，經解像測試後可達 100 lpi分辨力，而不同厚度透明片材中透鏡較大者，則可獲得大於0.5的MTF數值和最接近造鏡者公式的輪廓曲線參數，進而符合防偽印刷使用需求。

關鍵字：折射型微透鏡陣列、UV噴墨印刷、1951 USAF 、調變轉換函數（MTF）

The development of refractive micro-lens array remains limited because of the complex process, expensive cost, and finite format offered. In this study, transparent UV Inkjet ink was used to print the refractive micro-lens array, which was controlled for refractive conditions by using materials selected based on their thickness and micro-lens area coverage. The purpose of the study was to use a novel and flexible method to fabricate refractive micro-lens arrays and to improve current production processes. The concept of Moiré magnifier was used to design differently sized image files of lens arrays, and transparent ink was employed in UV inkjet printing to form the structure of micro-lenses on transparent materials with different thicknesses. The 1951 USAF resolution measuring chart is used to obtain the quantitative resolution of the structure of the UV inkjet refractive micro-lens array. The curvature of micro-lens contours and Modulation Transfer Function (MTF) were measured to analyze the image quality from the micro-lens array. The results show that the use of UV inkjet printing to produce a micro-lens array is a pragmatic method, and the array exhibits resolving power of 100 lpi. The larger lens area coverage at different thicknesses exhibits MTF number greater than 0.5, which meets commercial requirements. Furthermore, the micro-lens array fabricated in this study has potential value in anti-counterfeiting applications.

Keywords : 1951 USAF test card, MTF, micro-lens array, UV ink-jet printing