Projection screen based on reconfigurable holographic optics for implementation in head-mounted displays

摘要

A head-mounted display system and a method of displaying scenes within the system include two or more reconfigurable holographic optical elements (HOEs) in a holographic diffuser of the system. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as optimally diffusing light with respect to intensity toward a predefined direction. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field. Stacks of these reconfigurable HOE are utilized to selectively diffuse monochromatic images projected from an image generator to either the right or the left eyepiece optics of the system to present a displayed virtual scene in either a stereoscopic form or a binocular mono form. By utilizing more than one reconfigurable HOE stack for each projected image, the size of effective exit pupils at the eyepiece optics may be increased.