Micro-forging technique for rapid, low-cost manufacture of lens array molds and its application in a biomedical instrument

Interest in micro-optical components for applications ranging from telecommunications to the life sciences has driven the need for accessible, low-cost fabrication techniques. Most micro-lens fabrication processes are unsuitable for applications requiring 100% fill factor, apertures around 1 mm, and scalability to large areas with millions of lenses. A flexible, low-cost mold fabrication technique that utilizes a combination of milling and micro-forging is reported. The technique involves first performing a rough cut with a ball-end mill. Final shape and sag height are then achieved by pressing a sphere of equal diameter into the milled divot. Using this process, molds were fabricated for rectangular arrays of 1-10,000 lenses with apertures of 0.25-1.6 mm, sag heights of 3-130 [mu]m, inter-lens spacings of 0.25-2 mm, and fill factors of 0-100%. Mold profiles have roughness and figure error of 68 nm and 354 nm, respectively, for 100% fill factor, 1 mm aperture square lenses. The required forging force was modeled as a modified open-die forging process and experimentally verified to increase nearly linearly with surface area.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Saez, Miguel Angel

Advisor dc:contributor.advisor

• Ian W. Hunter.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40478

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40478