Design of a See-Through Head-Mounted Display with a Freeform Surface

Abstract

This paper described an off-axis head-mounted display system. It is composed of a 7-piece coaxial relay lens group and a freeform surface combiner. This configuration has a simple structure and a wide field of view (FOV). In this design, a freeform surface is chosen as the combiner, to simplify the structure and attain good image quality. We generated this freeform surface by considering both coordinates and normals of discrete data points. Moreover, we realize a coaxial structure in the relay lens group, which is compact and benefits from a loose tolerance requirement. The HMD system we finally realized has a 40°× 30° FOV and 15-mm exit pupil diameter.

Polarization Volume Gratings for Near-Eye Displays and Novel Photonic Devices

“…Besides novel optical elements, the unique properties of PVGs also open new space in near-eye displays, especially novel optical systems for augmented reality (AR) displays. At the current stage, there are still many unresolved challenges in near-eye display systems, such as expanding field of view (FOV), increasing the system efficiency, generating more depths to decrease the dazzling, and improving the uniformity of image [4,55,56]. The combination of PVGs and new optical systems offers intriguing solutions for near-eye displays [4].…”

Near‐Eye Display and Tracking Technologies for Virtual and Augmented Reality

“…Gilboa proposes an off‐axis single‐element curved beam combiner [Gil91], and explores the associated optical design space. Today, modern variants of off‐axis single‐element curved beam combiners (e.g., Wang et al [WLX16]) are deployed in military applications and consumer‐level prototypes (e.g., Meta 2). Major limitations in off‐axis single‐element curved beam combiners come into play while extending FoV in horizontal directions when lit vertically; these combiners are known to provide poor imaging characteristics with eccentricity, and require a larger screen with a larger FoV demand.…”

A Novel Approach for Measurement of Free-Form Optical Elements with Digital Holographic Microscopy

“…An increasing number of optical systems are using them as key elements to improve the performance of optical systems. For example, free-form optical elements are used in vehicle and street lamps to increase the effective illumination range and improve energy efficiency [ 1 , 2 , 3 , 4 ], and in head-mounted displays [ 5 , 6 , 7 , 8 , 9 ] and micro-projectors [ 10 , 11 , 12 , 13 , 14 ] to reduce size and weight and improve imaging quality. However, due to their high complexity and non-rotational symmetry, high-precision measurement of free-form optical elements faces significant challenges, namely, how to further improve measurement accuracy, measurement efficiency and measurement versatility to achieve the high performance and low cost required for their areas of application.…”