Binocular retinal scanning laser display with integrated focus cues for ocular accommodation

In natural vision, the oculomotor processes of accommodation (focus) and vergence (angle between lines of sight of two eyes) are reflexively linked such that a change in one drives a matching change in the other. Conventional stereoscopic displays require viewers to decouple these processes, and accommodate at a fixed distance while dynamically varying vergence to view objects at different stereoscopic distances. This decoupling generates eye fatigue and compromises image quality. We describe a binocular display that generates variable accommodation cues that match vergence and stereoscopic retinal disparity demands, better approximating natural vision and leading to decreased eye fatigue. In our display, a luminance modulated laser beam is reflected from a deformable membrane mirror and raster scanned. The scan is converged at the entrance pupil of the viewer’s eye, creating a Maxwellian view of the displayed image. As the beam is scanned, the deformable membrane mirror dynamically changes the beam divergence angle to present images at different focal distances. The display has a large range of focus (closer than the viewer’s near point to infinity) and presents images at 60 Hz. The accommodation response of a viewer to the display was measured objectively using an infrared autorefractor.