“It turns out to be as thin as VR display sunglasses” Developed by Professor Lee Byong-ho of Seoul National University

Professor Lee Byung-ho’s team at the Department of Electrical and Information Engineering at Seoul National University has announced the development of a new VR display technology that can significantly reduce the size of a large headset-type VR (virtual reality) device.

The reason why the volume of existing VR displays is so large is the space inside. To reduce the thickness of this space, the VR optical system should reduce the focal length of the lens, but for the minimum distance to be maintained between the eye and the lens (eye relief) there is a limit to where a lens can use a very small focal length. The research team set out to develop a new VR optical system that could overcome these limitations.

The lens array VR display proposed by the research team is a structure in which a two dimensional lens array is added in addition to the existing lens. A two-dimensional lens array is an optical device in which small lenses are mounted in parallel. In the construction of this optical system, the actual focal length of the lens can be reduced by halving compared to the previous one, while preserving the eye relief distance.

In addition, the research team experimented with the technique of folding the optical path so that light travels back and forth in the space of the optical system by controlling the polar state of the light. This way, the same effect can be achieved by securing an optical path with sufficient physical distance, reducing the required space by an additional 1/3. Accordingly, the total volume is reduced to less than 1/6. As a result, the research team succeeded in developing the VR optical system design, which in theory only required a thickness of 3.3 mm.

The key element of this technology is to compensate for the inherent defects of the lens range through light field analysis and to optimize the optimal performance of the VR. The display optical system developed by the research team was not only thinner, but also 102 degrees wider and 102 degrees longer, with an 8.8 mm wide eye socket and an eye relief distance of 20 mm.

The research team unveiled a spectral-type prototype made using a liquid crystal display (LCD) display panel and a Fresnel lens. This scene-type device has a thickness of 8.8 mm, including the thickness of the necessary elements such as interior space, LCD panel and Fresnel lens.

Researcher Ki-Seung Bang, the first author of the research paper, said, “The glasses-type VR display designed this time will solve problems such as uncomfortable fit and limited use environment that have not been solved for 10 years.” “We need virtual reality and augmented reality hardware to run.

The results of this research will be published in the IEEE VR on March 29 and in the journal ‘IEEE TVCG (Visualization and Computer Graphics on Transactions)’ on March 25. ciokr@idg.co.kr