Piezo-Actuated Varifocal Head-Mounted Displays for Virtual and Augmented Reality

摘要

A fundamental cause of visual discomfort in traditional head-mounted displays (HMDs) for Virtual and AugmentedReality (VR/AR) is the vergence-accommodation conict (VAC).We propose and develop a novel headsetprototype based on the VerifocalTM platform to eliminate VAC by dynamically adjusting the focal plane of thedisplay. The developed headset employs an eye tracking system to track the user's gaze and determine the virtualobject being observed by the user. The varifocal display then moves the focal plane of the display to dynamicallymatch the depth of the observed object, providing correct focus cues to the user. We achieve the focal planeadjustment by moving the headset's stereo displays independently using small, lightweight and low-power piezoelectricactuators. Such actuators offer a very low response time with high positional accuracy, while operating ata high speed and virtually silently. Furthermore, our headset prototype has a large adjustable dioptric range foreach eye and thus provides the capability for also correcting myopia and anisometropia, allowing vision-impairedusers to use the headset without the need for eyeglasses. In conclusion, our approach makes it possible for theuser to observe close or far objects in the virtual environment with reduced eye strain by providing consistentdepth cues for all viewing distances.