Augmenting reality (AR) holds many benefits in how people perceive information and use it in their workflow or leisure activities. A cohesive AR experience has many components; nevertheless, the key is display technologies. The current industry standard for the core solution is still conventional stereoscopy, which has proven to be inadequate for near-work due to the caused vergence–accommodation conflict and the inability to precisely overlay the 3D content on the real world. To overcome this, next-generation technologies have been proposed. While the holographic method holds the highest potential of being the ultimate solution, its current level of maturity is not sufficient to yield a practical product. Consequently, the next solution for near-work-capable AR displays will be of another type. LightSpace Technologies have developed a static multifocal display architecture based on stacked liquid crystal-based optical diffuser elements and a synchronized high-refresh rate image projector. A stream of 2D image depth planes comprising a 3D scene is projected onto respective physically-separated diffuser elements, causing the viewer to perceive a scene as continuous and having all relevant physical as well as psychological depth cues. A system with six image depth planes yielding 6 cpd resolution and 72° horizontal field-of-view has been demonstrated to provide perceptually continuous accommodation over 3.2 Diopter range. A further optimization by using a conventional image combiner resulted in the compact and practical design of the AR display.

Solid-state multi-focal and volumetric technologies highlight the future of 3D-display development. One of the most convenient implementations of multi-focal 3D displays are stacks of transparent liquid crystal displays. In this work, the core element is dissected—a switching optical diffuser element based on cholesteric liquid crystals, playing the role of a transparent display. In the present study, high-speed synchronized optical spectroscopy is used. We analyzed the kinetic and electro-optical characteristics of the diffuser element, the operation of which is based on the switching between diffuse and transparent states of this element. The underlying aim of this study was to investigate ways to improve some of these characteristics. It has been found that the transient peak in the optical transmission during field-off state, which is reducing the intensity of the light scattered by the diffuser element, is likely not associated to the assumed formation of the transient planar state. As the origin of this peak, we suggest a transient state possessing uniform lying helix structure, formed due the material flow taking place in the cell during relaxation of the liquid crystal. The role of the contacting surface’s pre-tilt angle in the switching process of the liquid crystal diffuser was established.

We report the measuring method of scattering type display liquid crystal layer thickness based on capacitance values suitable for inline production process control. The method is selected for its effectiveness and simplicity over spectroscopic methods as conventional methods for scattering type displays are not applicable. During the method approbation process, a novel diffuser liquid crystal mixture refractive index was determined based on liquid crystal layer thickness measurement data.