Abstract

A novel two-step method for manufacturing microlens array molds by combining microindentation and precision polishing is proposed. Compared with conventional manufacturing methods, such as single-point diamond turning, this two-step method, as an alternative method, presents great advantages on cost and flexibility on spherical microlens array mold fabrication. Various curvatures of radii and arrangements for microlens array molds can be fabricated in the same way. In this paper, a hexagonal microlens array with 1.58 mm curvature radius was demonstrated to prove the feasibility of the proposed method. First, a large number of precise steel balls were organized in hexagonal arrangement and pressed into the mold’s surface to generate multiple microdimples. Second, the pileups around the microdimples were removed from the mold surface by precision polishing. The geometrical accuracy and surface quality were investigated by an optical surface profiler. The measurement indicated that, compared with the initial surface, the surface inside the dimple had significantly higher hardness and better surface quality than that of the steel balls. Then the microlens array on the mold was further replicated to poly(methyl methacrylate) substrates by a precision compression molding process. The experimental results showed that the fabricated mold and the polymer replicas have high fidelity, great uniformity, and good surface roughness. The proposed two-step, low-cost mold fabrication method can produce highly uniform microlens arrays and is therefore suitable for high-volume fabrication of precise optical elements such as integrated light-emitting diodes and other similar micro-optics.

© 2020 Optical Society of America

Mechanisms and optimization for the rapid fabrication method of polymeric microlens arrays

Asit Kumar Gain and Liangchi Zhang
Appl. Opt. 59(2) 405-412 (2020)

Effects of interface thermal resistance on surface morphology evolution in precision glass molding for microlens array

Jiaqing Xie, Tianfeng Zhou, Benshuai Ruan, Yifei Du, and Xibin Wang
Appl. Opt. 56(23) 6622-6630 (2017)

Fabrication of an infrared Shack–Hartmann sensor by combining high-speed single-point diamond milling and precision compression molding processes

Lin Zhang, Wenchen Zhou, Neil J. Naples, and Allen Y. Yi
Appl. Opt. 57(13) 3598-3605 (2018)

Replication of optical microlens array using photoresist coated molds

M. Chakrabarti, C. Dam-Hansen, J. Stubager, T. F. Pedersen, and H. C. Pedersen
Opt. Express 24(9) 9528-9540 (2016)

Precision compression molding of glass microlenses and microlens arrays—an experimental study

G. C. Firestone and A. Y. Yi
Appl. Opt. 44(29) 6115-6122 (2005)