Demonstration of Dynamic Focus Liquid Crystal Lenses by Meta Reality Labs

In collaboration with Kent State University, Meta Lab has created a liquid crystal lens with dynamic focus, used in creating Varifocal VR Headsets.
In the Virtual Reality R&D space, one of the trending topics is finding a specific solution for the so-called Vergence-Accommodation Conflict. The VR headsets currently on the market for consumers use stereoscopy to create 3D imagery, supporting the Vergence reflex but not the accommodation reflex.

In actual entities, these two always work in parallel, but in the VR world, they are apart because the eyes continue to meet where demanded. Still, their accommodation remains stationary because the light is all coming from the same distance (the display). Experimenters in the field say VAC can beget eye strain, make it delicate to concentrate on close imagery, and may indeed limit optical absorption.
Potential Solution

With the help of different technology, several experiments were held to use it on varifocal headsets that simultaneously support Vergence and Accommodation. But it is hard to crack the code on practical, less expensive, and large production to resolve the VAC.

Another solution for VAC is dynamic focus liquid crystal lenses which can adjust their focal length as voltage changes. According to KS University graduate students project on it previously, with small focal lenses with persistent switching time.

The researchers used 5cm dynamic focus LC Lenses to identify strengths and weaknesses in other extensive experiments. On the strength side, the researcher found that the Dynamic focus Len achieves high image quality towards the center while supporting a dynamic focus range from -0.80D to +.80D with 500ms Switching speed.

On the weakness side, the researcher found that the dynamic LC lens decreases the image quality due to phase reset, i.e., scattering of light due to the ridges in Fresnel lenses.

Finally, the researcher stated that the dynamic LC Lens provides better image quality with a gaze angle of about 30┬░, primarily similar to many VR headsets with a Fresnel lens.

Researchers say that combining the dynamic focus lens with a traditional lens creates a varifocal headset. To accurately track the eye movements and adjust the focal distance for the desired depth, the system must also detect where the user is looking.