Andreas Georgiou

Holographic near-eye displays for virtual and augmented reality

We present novel designs for virtual and augmented reality near-eye displays based on phase-only holographic projection. Our approach is built on the principles of Fresnel holography and double phase amplitude encoding with additional hardware, phase correction factors, and spatial light modulator encodings to achieve full color, high contrast and low noise holograms with high resolution and true per-pixel focal control. We provide a GPU-accelerated implementation of all holographic computation that integrates with the standard graphics pipeline and enables real-time (≥90 Hz) calculation directly or through eye tracked approximations. A unified focus, aberration correction, and vision correction model, along with a user calibration process, accounts for any optical defects between the light source and retina. We use this optical correction ability not only to fix minor aberrations but to enable truly compact, eyeglasses-like displays with wide fields of view (80°) that would be inaccessible through conventional means. All functionality is evaluated across a series of hardware prototypes; we discuss remaining challenges to incorporate all features into a single device.

Virtual image display as a backlight for 3D.

We describe a device which has the potential to be used both as a virtual image display and as a backlight. The pupil of the emitted light fills the device approximately to its periphery and the collimated emission can be scanned both horizontally and vertically in the manner needed to illuminate an eye in any position. The aim is to reduce the power needed to illuminate a liquid crystal panel but also to enable a smooth transition from 3D to a virtual image as the user nears the screen.

Curved wedges and shearing gratings for augmented reality

Designer spectacles look great and we want the same for a virtual display. A curved wedge guide will be described that can transfer the virtual image from a projector near the ear round to the pupil of the eye. The eye-box is tiny but the plan is to steer it so as to follow the pupil of the eye and this will be done by shearing the holographic combiner. Ray-tracing predicts a field of view of 115° per eye and a resolution of 2000 pixels per radian at the fovea using pre-distortion in the projector. Guide tolerances are lax, image accommodation is variable and a few milliWatts suffice to steer the pupil.