AR Displays: Next-Generation Technologies to Solve the Vergence–Accommodation Conflict

Abstract

Augmenting reality (AR) holds many benefits in how people perceive information and use it in their workflow or leisure activities. A cohesive AR experience has many components; nevertheless, the key is display technologies. The current industry standard for the core solution is still conventional stereoscopy, which has proven to be inadequate for near-work due to the caused vergence–accommodation conflict and the inability to precisely overlay the 3D content on the real world. To overcome this, next-generation technologies have been proposed. While the holographic method holds the highest potential of being the ultimate solution, its current level of maturity is not sufficient to yield a practical product. Consequently, the next solution for near-work-capable AR displays will be of another type. LightSpace Technologies have developed a static multifocal display architecture based on stacked liquid crystal-based optical diffuser elements and a synchronized high-refresh rate image projector. A stream of 2D image depth planes comprising a 3D scene is projected onto respective physically-separated diffuser elements, causing the viewer to perceive a scene as continuous and having all relevant physical as well as psychological depth cues. A system with six image depth planes yielding 6 cpd resolution and 72° horizontal field-of-view has been demonstrated to provide perceptually continuous accommodation over 3.2 Diopter range. A further optimization by using a conventional image combiner resulted in the compact and practical design of the AR display.

When virtual and real worlds coexist: Visualization and visual system affect spatial performance in augmented reality

“…Nowadays, different display architectures ranging from multifocal and varifocal to light field and holographic ( Love et al, 2009 ; Hu & Hua, 2014 ; Chang, Kumar, & Sankaranarayanan, 2018 ; Huang & Hua, 2018 ; Zabels et al, 2019 ; Chan, Bang, Wetzstein, Lee, & Gao, 2020 ; Zhan et al, 2020 ) are proposed to provide the better correspondence of binocular and focus cues. Considering the specifics of human vision, it is important to understand that the correct focus cues may not result in veridical percepts of spatial relations between objects and images in augmented reality.…”

“…Images were presented using a LightSpace Technologies IG-1005 prototype headset ( Zabels et al, 2019 ). It is a stereoscopic augmented reality display device utilizing stacked switchable optical diffuser elements (liquid-crystal diffusers) to physically separate display planes ( p 1 - p 4 ).…”

“…The resultant conflicts between binocular and focus cues can be associated with discrepancies in spatial perception ( Condino, Carbone, Piazza, Ferrari, & Ferrari, 2020 ; Peillard, Argelaguet, Normand, Lécuyer, & Moreau, 2020 ). New visualization approaches, such as multifocal, varifocal, and holographic displays, aim to mitigate or eliminate this issue ( Rolland, Krueger, & Goon, 2000 ; Huang & Hua, 2018 ; Zabels, Osmanis, Narels, Gertners, Ozols, Rutenbergs, & Osmanis, 2019 ; Zhan, Xiong, Zou, & Wu, 2020 ). Nevertheless, the actual user gain remains difficult to predict due to high interindividual variability and lack of agreement in perceptual studies on whether consistency of binocular and focus cues is a mandatory requirement for accurate spatial judgments in augmented reality ( Watt, Akeley, Ernst, & Banks, 2005 ; Hoffman, Girshick, Akeley, & Banks, 2008 ; Naceri, Chellali, & Hoinville, 2011 ; Peillard et al, 2019 ; Erkelens & MacKenzie, 2020 ; Peillard, Itoh, Normand, Argelaguet, Moreau, & Lecuer, 2020 ; Gao, Peillard, Normand, Moreau, Liu, & Wang, 2020 ).…”

“…As the conflict between binocular and focus cues has been identified as a paramount issue affecting user comfort, the alternative approaches for display architectures have been developed to mitigate or eliminate it. In particular, several studies provided some theoretical and experimental support for the implementation of multiple planes in the architecture of the display's optical element ( Rolland, Krueger, & Goon, 1999 ; Akeley, Watt, Girshick, & Banks, 2004 ; Watt et al, 2005 ; Hoffman et al, 2008 , MacKenzie, Hoffman, & Watt, 2010 ; Shibata et al, 2011 ), leading to a growing interest toward the practical implementation of this approach in augmented reality headsets ( Rolland, Krueger & Goon, 2000 ; Love, Hoffman, Hands, Gao, Kirby, & Banks, 2009 ; Hu & Hua, 2014 ; Chang, Kumar, & Sankaranarayanan, 2018 ; Huang & Hua, 2018 ; Zabels et al, 2019 ; Zhan et al, 2020 ). The key underlying idea is to use several distinct image planes in order to minimize the magnitude of the conflict between binocular and focus cues, thus covering a wider range of distances for comfortable viewing.…”

Visual Search Performance and Strategy for Three-Dimensional Visualization Systems: Impact of Radiologist Experience

“…The prolonged use of stereoscopic displays provokes discomfort, which occurs due to the mismatch between accommodation and vergence [21]. It is believed that the symptoms related to stereoscopic viewing can be eliminated in the foreseeable future by improving the resolution and sampling rate of the visualization system [14] or by utilizing a multifocal architecture for the optical element, which has originally been applied in volumetric displays within a wearable display [22]. With improvements in viewing conditions, stereoscopic visualization is expected to become acceptable for long-term use on a daily basis for the purpose of medical image reading.…”