HoloBeam: Paper-Thin Near-Eye Displays

An emerging alternative to conventional Augmented Reality (AR) glasses designs, Beaming displays promise slim AR glasses free from challenging design trade-offs, including battery-related limits or computational budget-related issues. These beaming displays remove active components such as batteries and electronics from AR glasses and move them to a projector that projects images to a user from a distance (1–2 meters), where users wear only passive optical eyepieces. However, earlier implementations of these displays delivered poor resolutions (7 cycles per degree) without any optical focus cues and were introduced with a bulky form-factor eyepiece ($\sim 50\ mm$ thick). This paper introduces a new milestone for beaming displays, which we call HoloBeam. In this new design, a custom holographic projector populates a micro-volume located at some distance (1–2 meters) with multiple planes of images. Users view magnified copies of these images from this small volume with the help of an eyepiece that is either a Holographic Optical Element (HOE) or a set of lenses. Our HoloBeam prototypes demonstrate the thinnest AR glasses to date with submillimeter thickness (e.g., HOE film is only $120\ \mu m$ thick). In addition, HoloBeam prototypes demonstrate near retinal resolutions (24 cycles per degree) with a 70 degrees-wide field of view.