Evaluation of a 6-DOF inkjet printer for the production of microstructures on curved surfaces using UV curable resin

In recent scientific studies it has been demonstrated that specialised spectacle lenses with incorporated microlenslets can help to correct the vision of children, suffering from myopia.1 While these lenses can be manufactured in large quantities via molding techniques, individualized customization presents significant challenges, such as high costs and production lead times. A solution for this issue would be a setup capable to produce those lenses by printing custom patterns of lenslets on various different lens surfaces. The idea is a multistep process in which you would print a liquid, UV curable resin on a curved surface. After which those droplets will be partly cured to guarantee stability while further deformation is possible. Our contribution is a novel system, designed to print in 6 Degrees of Freedom (6-DOF) on non-planar surfaces, that also can partly cure the material. For the purposes of this paper we will have a look at the setup and printing process of this system. This paper outlines our experimental setup utilized to print lenslets with a diameter of 140 µm to 1000 µm. Our in-house developed system is based on two industrial robot arms to maneuver the printhead and the UV structuring unit towards the substrate. A hexapod platform is used to precisely orientate the substrate under the printhead during the printing process. The presented results show the capability of the system to print arbitrary micro-lens arrays on 3D surfaces. This shows a possible solution for customized myopia correction on a commercial scale.