Positioning Monocular Optical See Through Head Worn Displays in Glasses for Everyday Wear

TL;DR

This paper addresses the problem of where to position a monocular optical see-through display in everyday wear. By synthesizing findings across aviation, automotive, and eyewear studies, it advocates a right-eye offset from the PPOG to minimize interruptions while preserving comfort and performance, proposing a vertically centered image with offsets between $+8.7^ extcircled{}$ and $+23.7^ extcircled{}$ and a practical $FOV$ around $15^ angle^ extcircled{}$ for reading-like tasks. The work provides concrete guidelines: for long-form reading in daily use, center-right offsets near the nose are preferable, while for short glanceable interactions offsets toward the ear are more tolerable, with the overall target of avoiding the PPOG by at least $8^ olinebreak[4]{}$ degrees. It also discusses social acceptance through lens tinting, optic edge placement, and ease of perception by bystanders, offering a holistic framework for designing monocular OST-HWDs that are less interruptive and more socially acceptable. The findings have practical impact for hardware developers seeking to integrate lightweight intelligent eyewear into daily life without sacrificing usability or acceptance.

Abstract

Head-worn displays for everyday wear in the form of regular eyeglasses are technically feasible with recent advances in waveguide technology. One major design decision is determining where in the user's visual field to position the display. Centering the display in the principal point of gaze (PPOG) allows the user to switch attentional focus between the virtual and real images quickly, and best performance often occurs when the display is centered in PPOG or is centered vertically below PPOG. However, these positions are often undesirable in that they are considered interruptive or are associated with negative social perceptions by users. Offsetting the virtual image may be preferred when tasks involve driving, walking, or social interaction. This paper consolidates findings from recent studies on monocular optical see-through HWDs (OST-HWDs), focusing on potential for interruption, comfort, performance, and social perception. For text-based tasks, which serve as a proxy for many monocular OST-HWD tasks, we recommend a 15° horizontal field of view (FOV) with the virtual image in the right lens vertically centered but offset to +8.7° to +23.7° toward the ear. Glanceable content can be offset up to +30° for short interactions.

Figures (15)

• Figure 1: Google Glass in 2014 and Vuzix Z100 in 2024.
• Figure 2: Field of view versus field of regard.
• Figure 3: Illustration of three elevation and azimuth angles relative to the right eye (by Chua et al. with permission) chua.
• Figure 4: Nine display positions on a monocular OST-HMD studied by Chua et al. (reproduced with permission) chua. The red rectangle on the diagrams located at the top left corner of each image indicates the display position from the user's point of view.
• Figure 5: Illustration of eye ranges defined by Sidenmark et al. sidenmark2023coordinated.