Arrays of microlenses with variable focal lengths fabricated by restructuring polymer surfaces with an ink-jet device

Abstract

Abstract:We report of a method for fabricating two-dimensional, regular arrays of polymer microlenses with focal lengths variable between 0.2 and 4.5 mm. We first make concave microlenses by ink-jetting solvent on a polymer substrate with a commercial drop-on-demand device. Solvent evaporation restructures the surface by a series of combined effects, which are discussed. In the second step we obtain convex elastomeric microlenses by casting the template made in the first step. We demonstrate the good optical quality of the microlenses by characterising their surfaces with atomic force microscopy and white light interferometry, and by directly measuring their focal lengths with ad-hoc confocal laser scanning microscopy.

Inkjet Printing of Functional Materials for Optical and Photonic Applications

“…Inkjet etching using drops of solvents on PS substrates has also been proposed to obtain polymer microstructures which can be used as microlenses [79,80,81]. Depending on the ratio of solvents in the jetted mixture the profile of the surface can be finely tuned going from concave to convex profiles in the same target substrate [80].…”

“…Depending on the ratio of solvents in the jetted mixture the profile of the surface can be finely tuned going from concave to convex profiles in the same target substrate [80]. Later on, the inverse replica of these microlenses can be obtained by template casting using an elastomeric silicone (Sylgard 184, Dow Corning, Midland, MI, USA) [81]. …”

The effect of droplet ejection frequency on the dimensions of inkjet-etched micro-via holes in poly4(-vinyl phenol) thin films

“…Nonetheless, this phenomenon can be used for deliberately modulating printed structures for many applications. For example it has been demonstrated that it can be used to fabricate concave and convex microlenses [7,8] and light emitting diodes (LEDs) [9] that can be used in optoelectronics. Studies on using inkjet or other dispensing tools to define structures in polymers and the influence of factors on the appearance and dimensions of the generated features have also been carried out.…”

A mechanism of the penetration limit for producing holes in poly(4-vinyl phenol) films by inkjet etching

“…These polymer patterning investigations can be potentially useful in some structural or functional applications. Bonaccurso et al [17] and Pericet-Camara et al [18] used inkjet printing to fabricate microvessels and microlenses while Xia et al [19,20] and Lu et al [21] demonstrated using the same technique to create cavities for display applications.…”