Going Blank Comfortably: Positioning Monocular Head-Worn Displays When They are Inactive
Co-Authors: Parth Arora, Rajandeep Singh, Srikanth T Varadharajan, Malcolm Haynes, Thad Starner
Head-worn displays (HWDs) have emerged as a significant technology trend over the past decade, making augmented reality experiences more accessible to consumers. While some HWDs are designed for tasks where the display is continuously active, smart AR glasses targeted to consumers are built for everyday wear. More often than not, the display of these glasses will be turned off. When designing these devices, it is crucial to consider the user experience both when the display is on and when it is inactive.
Our recent paper, “Going Blank Comfortably: Positioning Monocular Head-Worn Displays When They are Inactive,” presented at the 2023 International Symposium on Wearable Computers (ISWC ‘23), explores the optimal positioning of optical combiners in HWDs to enhance user comfort during periods of inactivity. The study involved two experiments to determine the most comfortable placement of these optical components, shedding light on an often-overlooked aspect of HWD design.
The Comfort of Inactive Displays
When an HWD is inactive, users may still perceive the optical combiners as out-of-focus seams or discolorations in their field of vision. These visual artifacts can be distracting and uncomfortable. The goal of the study is to investigate different combiner placements and identify the most comfortable configuration.
Experiment 1: Display Design Study
In the first experiment, the researchers presented participants with seven different models of optical combiner configurations, each inspired by existing HWDs or specialty eyewear. Participants ranked these models based on their comfort preferences. The results revealed that models with optical combiners placed away from the user’s primary position of gaze (PPOG), models VI and VII, were significantly more preferred than those in line with the PPOG. This finding aligns with previous research in automotive and aviation displays, suggesting that notifications and non-essential information should be positioned away from the user’s central vision. We decided to move forward with model VII, as participants commented that they felt less occlusion just like the nose has less occlusion in their vision.
Experiment 2: Determining Comfortable Positions
The second experiment aimed to determine the optimal offset distance of the optical combiner from the PPOG toward the nose. The study used eight different models with varying offsets (containing one control pair of glasses), allowing participants to experience different placements ranging from 0° to 30° toward the nose. Participants explored an art exhibition using each model and rated their comfort level during the experience. The results indicated that the nearest edge of the optical combiner should be positioned with an offset greater than 15° from the PPOG toward the nose to ensure user comfort during inactivity.
Methodology
To conduct this study we had participants evaluate the comfort and usability of simulated smart glasses in a controlled art exhibition setting. The research aimed to determine the most comfortable display area starting from the nasal position, with a focus on sedentary and low-attention tasks. Calibration was conducted to account for individual variations in interpupillary distance (IPD), and head movement was controlled during the experiment. Participants rated their comfort while experiencing different artworks with different pairs of glasses, including the six modeled pairs and one control pair. The study sought to provide insights into the user experience of smart glasses in a specific context, considering factors like comfort, individual differences, and head movement control. The comfort of our participants was plotted on the graphs below. More details can be found in our paper.
Implications for HWD Design
In conclusion, our first study (and the literature) suggests that user comfort can be improved by avoiding the user’s PPOG. Comfort may also be improved by keeping display optics boundaries simple to avoid unnecessary edges. The second study suggests that the nearest optical boundary to the PPOG should be placed with a more than 15° offset from the PPOG toward the nose. These experiments provide valuable insights for HWD manufacturers and designers. When considering the placement of optical combiners, it’s essential to balance the need for display visibility with user comfort.
You can read our paper here in ACM Digital Library to learn more about our work. We would be delighted to discuss our work with you in person or through email! Please get in touch with our lab if you are interested.
We look forward to hearing from you soon!
Yukun Song, Parth Arora, Rajandeep Singh, Srikanth T. Varadharajan, Malcolm Haynes, and Thad Starner. 2023. Going Blank Comfortably: Positioning Monocular Head-Worn Displays When They are Inactive. In Proceedings of the 2023 International Symposium on Wearable Computers (ISWC ‘23). Association for Computing Machinery, New York, NY, USA, 114–118. https://doi.org/10.1145/3594738.3611375
