The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain's power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies.

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Three-dimensional display technologies

In embodiments of a multiple waveguide imaging structure, a wearable display device includes left and right imaging units of respective display lens systems to generate an augmented reality image that includes a virtual image. Each of the left and right imaging units include a first waveguide for see-through viewing at a first field of view, where the first waveguide includes a first polarizing beam splitter to reflect light that enters at a first polarization orientation angle and pass through the light that enters at a second polarization orientation angle. Each of the left and right imaging units also include at least a second waveguide for see-through viewing at a second field of view, where the second waveguide includes a second polarizing beam splitter to reflect the light that enters at the first polarization orientation angle and pass through the light that enters at the second polarization orientation angle.

Multiple waveguide imaging structure

In embodiments of waveguide optics focus elements, an imaging structure includes a waveguide for viewing of an environment that is viewable with the imaging structure. The waveguide transmits light of a virtual image that is generated to appear as part of the environment for augmented-reality imaging or virtual-reality imaging. The imaging structure also includes one or more focus elements that are integrated in the waveguide and switchable to focus the virtual image at a focus depth that approximately correlates to a focal distance of the environment. The focus elements can each be implemented for a different focus depth of the virtual image, and the focus depth is adjustable based on a combination of the focus elements being switched-on or switched-off.

Waveguide optics focus elements

In embodiments of an imaging structure with embedded light sources, an imaging structure includes a silicon backplane with a driver pad array. The embedded light sources are formed on the driver pad array in an emitter material layer, and the embedded light sources can be individually controlled at the driver pad array to generate and emit light. A conductive material layer over the embedded light sources forms a p-n junction between the emitter material layer and the conductive material layer. Micro lens optics can be positioned over the conductive material layer to direct the light that is emitted from the embedded light sources. Further, the micro lens optics may be implemented as parabolic optics to concentrate the light that is emitted from the embedded light sources.

Imaging structure with embedded light sources

A lenticular-type super multi-view (SMV) display normally requires an ultra high-resolution flat-panel display. To reduce this resolution requirement, two or more views are generated around each eye with an interval smaller than the pupil diameter. Cylindrical lenses constituting a lenticular lens project a group of pixels of the flat-panel display to generate a group of viewing zones. Pixel groups generating left and right viewing zones through the same cylindrical lens are partitioned to separate the two zones. The left and right pixel groups for different cylindrical lenses are interlaced horizontally. A prototype SMV display is demonstrated.

Super multi-view display with a lower resolution flat-panel display.

The construction and operation of two laser-based glasses-free 3D (autostereoscopic) displays that have been carried out within the European Union-funded projects MUTED and HELIUM3D is described in this paper. Both use a multi-user head tracker to direct regions viewer's referred to as exit pupils to viewer's eyes. MUTED employs a direct-view LCD whose backlight comprises novel steering optics and in HELIUM3D image information is supplied by a horizontally-scanned fast light valve whose output is controlled by a spatial light modulator (SLM). The principle of operation, construction and results obtained are described.

Laser-Based Head-Tracked 3D Display Research

This paper describes multi-user autostereoscopic displays developed within the European Union-funded MUTED and HELIUM3D projects. These utilize head tracking in order to provide images that are displayed in regions referred to as exit pupils that follow the users' eye positions. In the MUTED displays images are produced on a direct-view liquid crystal display (LCD) with novel optics controlled by the head tracker replacing the conventional backlight. This paper describes the design and construction of the displays along with evaluation results and future developments. The principle of operation, the current status and the multimodal potential of the HELIUM3D display is described.

MUTED and HELIUM3D autostereoscopic displays

This paper describes the design and building of a novel stereoscopic display that does not require the wearing of special eye-wear (autostereoscopic) and employs head position tracking in order to enable a large degree of freedom of viewer movement and the display of the minimum amount of information. A stereo image pair is produced on a single liquid crystal display (LCD) by simultaneously displaying left and right images on alternate rows of pixels. Novel steering optics controlled by the output of a head position tracker is used to direct regions, referred to as exit pupils, to the appropriate viewers' eyes.

Multi-user glasses free 3D display using an optical array

— Research described in this paper encompasses the design and building of glasses-free (autostereoscopic) displays that utilize a direct-view liquid-crystal display whose backlight is provided by a projector and novel steering optics. This is controlled by the output of a multi-user head-position tracker. As the displays employ spatial multiplexing on a liquid-crystal-display screen, they are inherently 2-D/3-D switchable with 2-D being achieved by simply displaying the same image in the left and right channels. Two prototypes are described in this paper; one incorporating a holographic projector and the other a conventional LCOS projector. The LCOS projector version addresses the limitations of brightness, cross-talk, banding in the images, and laser stability that occur in the holographic projector version. The future development is considered and a comparison between the prototypes and with other 3-D displays is given.

MUTED: Multi-user 3-D display.

This paper presents the multi‐user autostereoscopic 3D display system constructed and operated by the authors using the time‐multiplexing approach This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high‐frame‐rate digital micromirror device (DMD) projector The whole system in this prototype consists of four major parts: a 120Hz high‐frame‐rate DMD projector, a 49‐element optical array, a 120Hz screen assembly, and a multi‐user head tracker The display images for the left/right eyes are produced alternatively on a 120Hz direct‐view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD The novel steering optics controlled by the multi‐us

Rajwinder Singh Brar

Papers

Laser-Based Head-Tracked 3D Display Research

MUTED and HELIUM3D autostereoscopic displays

Multi-user glasses free 3D display using an optical array

MUTED: Multi-user 3-D display.

A time‐multiplexed 3d display using steered exit pupils