VAN LCOS microdisplays: a decade of technological evolution

Abstract—Microdisplays of the liquid crystals on silicon (LCOS) type have gone through a rapid evolution during the last decade. We present an overview of how vertically aligned nematic (VAN) LCOS have evolved from an attractive, but notoriously difficult and even infamous technology, to the mainstream microdisplay technology that it is today. At the same time, we highlight a number of remaining issues and concerns, and present some ideas of how to remedy them

Electronic compensation for fringe-field effects in VAN LCOS microdisplays

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Next-generation air-navigation displays

Future airplanes could be fitted with several short-throw wide-angle LED projectors to create a seamless tiled cockpit interactive air-navigation display

A liquid crystal based contact lens display using PEDOT: PSS and obliquely evaporated SiO2

An active spherically conformed liquid crystal cell is presented comprising PEDOT:PSS as a transparent conductive layer and obliquely evaporated SiO2 as an alignment layer. To tackle compatibility issues with the SU8 processing needed for the spacers, an additional buffer layer was included in the fabrication process. The electro-optic response is inspected closely and a contrast measurement is given

Design and fabrication of blazed gratings for a waveguide-type head mounted display

In a waveguide-type display for augmented reality, the image is injected in the waveguide and extracted in front of the eye appearing superimposed on the real-world scene. An elegant and compact way of coupling these images in and out is by using blazed gratings, which can achieve high diffraction efficiencies. We report the design of blazed gratings for green light (lambda = 543 nm) and a diffraction angle of 43 degrees. The blazed gratings with a pitch of 508 nm and a fill factor of 0.66 are fabricated using grayscale electron beam lithography. We outline the subsequent replication in a polymer waveguide material with ultraviolet nanoimprint lithography and confirm a throughput efficiency of 17.4%. We finally show the in- and outcoupling of an image through two blazed gratings appearing sharp and non-distorted in the environment. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

A contact lens with built-in display: science fiction or not?

Recent progress in microsystems integration technology such as ultra-thin chip packaging, stretchable interconnections, thin-film batteries and organic photovoltaics makes it feasible to incorporate various electronic components and transducers in extremely confined spaces and inside flexible or conformable objects. Can this ultimately lead to a genuine display in a contact lens? The major outstanding issues are reviewed

Miniature Fresnel LC lens performance

The performance of miniature, polymer-based Fresnel liquid crystal lenses is discussed, specifically the sensitivity for non-uniformities

Miniature liquid crystal lens optimizations

Small, switchable liquid crystal based polymer Fresnel lenses are discussed, considering design optimizations for performance

Thin-film stretchable electronics technology based on meandering interconnections: fabrication and mechanical performance

A new fabrication technology for stretchable electrical interconnections is presented. This technology can be used to connect various non-stretchable polyimide islands hosting conventional electronic components. The interconnections are realized by patterning a 200 nm thick sputter-deposited gold film into meandering horseshoe shapes, functioning as 'two-dimensional springs' when embedded in a silicone elastomer. Polyimide support is introduced around the meandering conductors as a means to improve the mechanical performance. Processing is done on a temporary carrier; the islands and interconnections are embedded in polydimethylsiloxane in a final stage. To this end, a release technique compatible with high temperatures up to 350 °C based on the evaporation of a 400 nm thick layer of potassium chloride is developed. Test structures consisting of stretchable interconnections with a varying polyimide support width were fabricated. These were strained up to twice their original length without compromising their functionality. Also cyclic mechanical loading at various strains was performed, indicating the influence of the polyimide support width on the lifetime. At strains of 10%, a minimum lifetime of 500 000 cycles is demonstrated. The presented technology thus provides a promising route towards the fabrication of stretchable electronic circuits with enhanced reliability