Microlens Arrays above Interlaced Plasmonic Pixels for Optical Security Devices with High‐Resolution Multicolor Motion Effects

Abstract

AbstractOptical security devices based on high‐density microlens arrays on top of printed microimages or interlaced patterns can display high‐resolution image frames with attractive motion effects. However, the effects are so far restricted to a single color due to challenges in printing multiple colors with sufficiently high resolution and precision. This article introduces a viable solution based on microlens arrays above plasmonic colors to enable high‐resolution multicolor image frames with multidirectional motion effects. Plasmonic color pixels comprised of metalized nanowell arrays are implemented to print 2D interlaced patterns with super‐high resolution and nanoscale precision. Using a 2D microlens array of 25 µm lens pitch, 50 color image frames are obtained from a plasmonic color pattern printed with resolution of 10 160 dots per inch. The image frames show multiple colors, which significantly boost the color performance of microlens‐based security devices. The display resolution of image frames reaches 1016 pixels per inch, which is at least six times higher than conventional lenticular images. The color image frames also show excellent motion effects when moving the view point along any arbitrary direction. The presented devices can be advantageous for commercial applications in security, authentication, and product branding.