High-performance integral-imaging-based light field augmented reality display using freeform optics

Abstract

Abstract:A new integral-imaging-based light field augmented-reality display is proposed and implemented for the first time, to our best knowledge, to achieve a wide see-through view and high image quality over a large depth range. By using custom-designed freeform optics and incorporating a tunable lens and an aperture array, we demonstrated a compact design of a light field head-mounted-display that offers a true 3D display view of 30° by 18°, maintains a spatial resolution of 3 arc minutes across a depth range of over 3 diopters, and provides a see-through field of view of 65° by 40°.

Methods of optimizing and evaluating geometrical lightguides with microstructure mirrors for augmented reality displays

“…The fourth metric, S 4 , characterizes the amount of stray light coupled into the exit pupil and is defined as the average ratio of the stray light flux to the out-coupled flux through normal ray paths across the FOV. It is expressed as 4 1…”

“…A typical optical see-through HMD for AR applications minimally consists of a microdisplay, an eyepiece and an optical combiner, among which the optical combiner plays a critical role in determining the overall optical performance and system compactness of an AR displays. Several different technologies for constructing optical combiners have been developed, including a flat beamsplitter [1], a curved or freeform surface with a beamsplitter coating [2][3][4][5], a diffractive [6][7][8] or holographic waveguide [9][10][11][12][13], and a geometrical lightguide [14][15][16][17][18]. A flat beamsplitter is simple and low-cost, but its size scales up rapidly with the field of view (FOV) of a system and becomes impractical.…”

“…A flat beamsplitter is simple and low-cost, but its size scales up rapidly with the field of view (FOV) of a system and becomes impractical. A freeform combiner that uses either a coated freeform prism with a compensator [2][3][4] or a tilted off-axis partial reflector [5] can achieve a large FOV and high image quality, but its size typically is bulkier than holographic waveguides or geometric lightguides. Waveguides using diffractive optical element such as deep slanted nanometric gratings [8] or volume holograms [9][10][11][12][13], which couples and guides light through a substrate using diffractive techniques, has the advantage of being thin and compact, but it is very challenging to achieve a large FOV, high-quality uniform image, and low chromatic artifacts due to its high sensitivity to wavelengths and angles of incidence.…”

Digitally switchable multi-focal element for wearable displays

“…One of the methods to address the VAC problem in conventional stereoscopic 3D displays is to rapidly render multiple image planes distributed at different focal distances to create true 3D light field displays, in which a key enabling technology is an optical element with electrically tunable optical power, known as vari-focal element (VFE). Many methods have been proposed to achieve a multi-focal plane display, such as deformable membrane mirror device (DMMD) 3,4 , liquid lens 5,6 , birefringence material 7 , liquid crystal lens [8][9][10] .…”

“…The liquid lens Liu used 5 offers a large range of tunable optical power, but it has a limited response speed of 100 Hz and very small optical aperture of about 2.5-4 mm. The electronically tunable lens offered by Optotune Inc. is another emerging technology based on the combination of optical fluids and elastic polymer membrane 6,11 . It affords a large range of tunable power, low voltage control, and a large optical aperture (up to 16 mm).…”