Direct Fabrication of Metal Rollers with Microstructures sing Dry Film Resist and its Rolling Application
Date Issued
2008
Date
2008
Author(s)
Lee, Chih-Lung
Abstract
Conventionally, the precise optical elements are usually fabricated using injection molding and hot embossing processes. The disadvantages of these processes are long cycle time, residual stress in products, and limited replicating area. Hence, it is important and demanding to develop a continuous roller embossing process with the capacities of high throughput and rapid fabrication. A typical roller was made from that the thin metal sheet which had the microstructure was wrapped onto the roller. With this method, mold sliding and warping were observed during the process. On the other hand, if the mold was soft material, insufficient strength and poor durability of the mold were also problems. This study proposes a process of fabricating microstructures on the surface of metal rollers. The direct metal roller fabricating process involves three methods including dry film resist (DFR) laminating, wet etching and electroless plating process. Additionally, the flexible film photomask can be easily designed using CAD software; it enhances the design simplicity and flexibility, so the cost is lowered. In this study, three kinds of roller fabrication processes are developed: (1) lamination before exposure, etching process; (2) exposure before lamination, etching process; and (3) exposure before lamination, electroless plating process. The parameters of lamination, exposure and etching are also investigated. After the microstructure rollers have been fabricated, the metal rollers with microstructures are used both in the hybrid extrusion embossing system and roller UV micro-stamping process. he hybrid extrusion embossing system combines “ roller embossing ” and “ film extrusion ” methods to fabricate microlens arrays and grating on PC film. In this experiment, we discuss three conditions in the hybrid extrusion embossing system: (1) non-infrapara radiant ceramic heater using silicon roller; (2) with infrapara radiant ceramic heater using silicon roller; and (3) with infrapara radiant ceramic heater using rigid roller. The height of the microstructures on PC film is discussed. Second, the fabricated roller is used as the mold in the roller UV micro-stamping process to replicate grating pattern on PET film.inally, the microlens arrays with 86.98 μm diameter and 216 μm focal length are fabricated successfully using the roller mold with micro-holes array structures. This result proves that the rollers fabricated in this method can be used in roller embossing and UV micro-stamping for microstructure mass production.
Subjects
Dry Film Resist
Rolling
Type
thesis
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