Introduction to Holographic Display Systems
The goal of making Virtual Reality (VR) glasses which might be as thin and light-weight as regular glasses has been a longstanding challenge within the tech industry. Currently, VR headsets are bulky and uncomfortable to wear, mainly attributable to the thickness of their optical stacks. However, recent research by Meta and Stanford University has made significant progress in developing a brand new variety of display system that would potentially result in the creation of VR glasses with a complete optical stack thickness of lower than 3mm.
The Problem with Current VR Headsets
The thickness of current VR/MR headsets is nearly entirely driven by the optics and displays. While pancake lenses have enabled thinner headsets in recent times, the pancake lens stack itself continues to be relatively thick and heavy, much more so than glasses. This is a serious obstacle to creating VR glasses which might be comfortable to wear and supply a high-quality VR experience.
Breakthrough in Holographic Display Technology
The latest display system developed by Meta and Stanford researchers uses a real holographic approach, providing a practical 3D image with inherent depth cues. This mitigates a serious flaw with today’s headsets called the vergence-accommodation conflict, which causes discomfort for the user’s eyes. The prototype uses tiny fiber-coupled lasers, MEMS mirrors, and an optical waveguide to create a holographic eyepiece lens in front of the user’s eye.
How the New Display System Works
The system uses volume Bragg gratings (VBGs), that are angle-encoded to diffract a really narrow band of colours at very specific angles. This is different from traditional waveguides, which use surface relief gratings. The prototype also uses AI calibration, a neural network that learned how the sunshine changes because it passes through all the system, to regulate the spatial light modulator (SLM) and deliver a better quality output to the attention.
Comparison to Previous Research
Previous research prototypes have achieved significant advancements in holographic display technology, but they’ve limitations. For example, a 2020 prototype had a thickness of lower than 9mm but was only green-only and had a limited field of view. A 2022 prototype achieved a 2.5mm thickness but had a limited field of view and eyebox. The latest prototype from Meta and Stanford researchers achieves a 38° diagonal field of view and a big 9x8mm static eyebox, a major step forward.
Advancements and Limitations
The latest prototype is a major advancement in holographic display technology, however it still has limitations. The 38° diagonal field of view is way narrower than the roughly 115° of current VR headsets, and there isn’t a commercial-scale supply chain for the high-quality components utilized in the display system. However, the regular improvements in research on holographic display systems bring us closer to an eventual way forward for VR devices which might be no more cumbersome than reading glasses.
Conclusion
The research by Meta and Stanford University has made significant progress in developing a brand new variety of display system that would potentially result in the creation of VR glasses with a complete optical stack thickness of lower than 3mm. While there are still limitations to be overcome, the advancements in holographic display technology are promising, and we are able to expect to see significant improvements in the longer term. As the technology continues to evolve, we may someday see VR glasses which might be as thin and light-weight as regular glasses, providing a snug and high-quality VR experience for users.
