UV-curing Imprinting of Double-sided Aspheric Microlens Array
Date Issued
2016
Date
2016
Author(s)
Chen, Kuan-Yu
Abstract
In this research, UV curing imprint process is developed to fabricate a 4-inch double sided aspheric microlens array (5×5). Aluminum mold for aspheric microlens was first manufactured. Transparent PDMS mold core was replicated using the aluminum mold as the master. The PDMS mold cores were embedded in the PMMA mold base which was designed with alignment mark. A compressing machine customized for UV curing process with real-time optical alignment system was implemented for UV curing imprintng. After the UV-curable resin was coated on the cavity, the molds were slowly clamped and the cavity was filled. After the resin was cured with UV light, aspheric microlens array with convex profile on one side and concave profile on the other side was fabricated, the cycle time is 110 s. For the convex profile, the degree of replication was 98.58%, and 98.26% on the concave profile. As far as uniformity is concerned the coefficient of variation of diameter is 0.31%, while the coefficient of variation of height is 0.41%. The optical properties of the double-sided aspherical microlens were measured. The original light source of 1.2 mm diameter is reduced to 45 m as the spot diameter. The average effective focal length 1.433 mm and its coefficient of variation is 0.0065%, indicating the formability and uniformity. The G patterns is present a complete and clear optical image. This study demonstrates the potential of UV curing imprinting for forming double-sided aspheric microlens arrays for optical application.
Subjects
double-sided microstructure
aspheric
microlens array
UV curing
Type
thesis
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