SCIEN has resumed at Stanford with the talk Computational Near-Eye Displays with Focus Cues by Gordon Wetzstein. This presentation is an overview of research at Stanford.
Inflection points in near-eye displays:
- 1838 Stereoscopes by Wheatstone, Brewster, …
- 1968 Ivan Sutherland
- 1995 Nintendo Virtual Boy
- 2012–2017 VR explosion
Currently, the big enablers are the smartphone components.
The main purpose of the lenses in near-eye displays is to set the virtual image further away because we cannot focus too close.
Stereoptics is binocular; the mechanism of vergence is cued by binocular disparity. Focus cues are monocular; the mechanism of accommodation is cued by retinal blur.
The big problem is the vergence-accommodation conflict..
Gaze-contingent focus. For non-presbyopes, the adaptive focus is like the real world, but it requires eye tracking. Presbyopes need a fixed focal plane with correction.
Light field displays are not yet well-developed. The idea is to project multiple different perspectives into different parts of the pupil. Example: tensor displays. Light field displays are limited by diffraction.
The next step is multifocal lenses: point spread function engineering.
The challenges for AR are
- Design thin beam combiners using waveguides
- Eye box vs. field of view trade-off
- Eye tracking
- Chromatic aberrations
- Occlusions; difficulty: need to block real light
