Fabrication of curved diffractive optical elements by means of laser direct writing, electroplating, and injection compression molding. (November 2019)

• Record Type: Journal Article
• Authors: Roeder, M.; Thiele, S.; Hera, D.; Pruss, C.; Guenther, T.; Osten, W.; Zimmermann, A.
• Is Part Of: Journal of manufacturing processes. Volume 47(2019)
• Page Start: 402
• Page End: 409
• Publication Date: 2019-11
• Subjects: Diffractive optical element -- Laser direct writing -- Injection compression molding -- Polymer optics; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2019.10.012
• Languages: English
• ISSNs: 1526-6125

Abstract

Abstract: In this work, a new process chain for the fabrication of curved micro-structured optical elements by injection compression molding is investigated. The fabrication is demonstrated for the example of a curved diffractive optical element (DOE). In a first process step a master substrate is fabricated using laser direct writing on a curved glass substrate. Blazed diffractive micro-structures with lateral feature sizes down to 5 μm and height of 1.6 μm are created. A subsequent electroplating process is applied to create a nickel stamper to be used as a tool insert for the molding process. During electroplating, a 3 mm nickel layer is formed, transferring the diffractive structures from the master substrate into a solid mold insert. The nickel stamper shows an accurate reproduction of the micro-structures. The mold insert is integrated into an injection compression molding tool to replicate the optical elements. Results show that the blazed diffractive structures are replicated with a high quality. Tests of the components within a chromatic-confocal measurement setup confirm that they can potentially replace expensive conventional elements.