Examples of diffractive devices comprise a cholesteric liquid crystal (CLC) layer comprising a plurality of chiral structures, wherein each chiral structure comprises a plurality of liquid crystal molecules that extend in a layer depth direction by at least a helical pitch and are successively rotated in a first rotation direction. Arrangements of the liquid crystal molecules of the chiral structures vary periodically in a lateral direction perpendicular to the layer depth direction to provide a diffraction grating. The diffractive devices can be configured to reflect light having a particular wavelength range and sense of circular polarization. The diffractive devices can be used in waveguides and imaging systems in augmented or virtual reality systems.

An illumination system is provided. The illumination system includes a light source assembly configured to output a first polarized light having a first handedness. The illumination system also includes a light guide plate configured to guide the first polarized light received from the light source assembly and output a second polarized light having a second handedness opposite to the first handedness. The light guide plate includes two wedges coupled to one other at a slanted surface between the two wedges and a reflective polarizer disposed at the slanted surface. The illumination system also includes a reflective sheet arranged at a first side surface of the light guide plate and configured to reflect the first polarized light as the second polarized light. The reflective polarizer includes a birefringent material having a chirality, and is configured to selectively transmit the first polarized light and reflect the second polarized light.

According to one embodiment, a liquid crystal element includes a first transparent substrate, a second transparent substrate, and a first liquid crystal layer cured. The first liquid crystal layer contains first cholesteric liquid crystal and has a reflective surface which reflects first circularly polarized light having a first wavelength. A first helical axis of the first cholesteric liquid crystal is tilted in a uniform direction over an entire area of the first liquid crystal layer. Each of a first outer surface of the first transparent substrate and a second outer surface of the second transparent substrate forms an interface which totally reflects the first circularly polarized light reflected in the first liquid crystal layer.

A multi-spectral lens comprises a circular polarizer and a tunable cholesteric filter having an associated reflection band. Incoming light is circularly polarized to one handedness by the circular polarizer, and the tunable cholesteric filter transmits the circularly polarized light and reflects the opposite handedness of the circularly polarized light if within the reflection band of the filter, with the reflection band of the tunable cholesteric filter varying with a control voltage. In a preferred embodiment, a mirror is arranged to receive light transmitted by the tunable cholesteric filter and reflect it back towards the filter with flipped handedness, with the reflected light with flipped handedness that is within the reflection band of the tunable cholesteric filter reflected by the tunable cholesteric filter back toward the mirror. The architecture described effectively converts the reflection band of a tunable cholesteric filter into a tunable bandpass filter for a multi-spectral imaging lens.

An optical device includes a light source and a polarization selective optical element. The polarization selective optical element includes a stack of a plurality of cholesteric liquid crystal layers. The plurality of cholesteric liquid crystal layers includes a first cholesteric liquid crystal layer with liquid crystal molecules arranged in a first helical configuration having a first pitch range for light of a first wavelength range and a second cholesteric liquid crystal layer with liquid crystal molecules arranged in a second helical configuration having a second pitch range for light of a second wavelength range. The second wavelength range is different from the first wavelength range.

Provided is a display apparatus including a first cholesteric liquid crystal panel, a second cholesteric liquid crystal panel, and a third cholesteric liquid crystal panel. The first cholesteric liquid crystal panel has a light receiving surface. The second cholesteric liquid crystal panel overlaps the first cholesteric liquid crystal panel and is disposed on a side of the first cholesteric liquid crystal panel away from the light receiving surface. The third cholesteric liquid crystal panel overlaps the second cholesteric liquid crystal panel and is disposed on a side of the second cholesteric liquid crystal panel away from the first cholesteric liquid crystal panel. One of the first cholesteric liquid crystal panel, the second cholesteric liquid crystal panel, and the third cholesteric liquid crystal panel is provided with multiple first light shielding patterns separated from each other.

According to one embodiment, a liquid crystal display device includes a first liquid crystal device, a second liquid crystal device, and a liquid crystal display panel, the first liquid crystal device including a first substrate including a first electrode thereon, a second substrate including a second electrode thereon, and a first cholesteric liquid crystal layer, the second liquid crystal device including a third substrate including a third electrode thereon, a fourth substrate including a fourth electrode thereon, and a second cholesteric liquid crystal layer, wherein the first liquid crystal device and the second liquid crystal device are stacked successively.

A device for modulation of light (16) having a wavelength, comprising: a first substrate (10) with a first face (81) and a second opposite face (82), and comprising a first electrode (11); a second substrate (20) adjacent to the second face (82) and defining a gap between the first and second substrate (10, 20), the second substrate (20) comprising a second electrode (21); a responsive liquid crystal layer (15) disposed in the gap, wherein the responsive liquid crystal layer (15) has a flexoelectro-optic chiral nematic phase, and is birefringent with an optic axis that tilts in response to an applied electric field between the first and second electrode (11, 21); and a mirror adjacent to the second substrate (20), the mirror configured to reflect incident circular polarised light while preserving its handedness.

Provided are a novel optical element that can be used as a sensor or the like and a sensor including the same optical element. The optical element includes a cholesteric liquid crystal layer, in which the cholesteric liquid crystal layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction, and in a case where a cross-section taken in a thickness direction conforming the in-plane direction in which the direction of the optical axis rotates is observed using a scanning electron microscope, a portion where a bright line and a dark line derived from the cholesteric liquid crystalline phase are discontinuous is provided in the cholesteric liquid crystal layer in the in-plane direction in which the direction of the optical axis rotates.

A wavelength tunable optical filter and a method for switching and adjusting the wavelength tunable optical filter. The optical filter includes a liquid crystal cell comprising a cholesteric liquid crystal mixture inserted between two electrodes configured to apply a voltage, the cholesteric liquid crystal mixture comprising a chiral dopant and a dual frequency liquid crystal host material, the liquid crystal cell having a reference Bragg reflection wavelength in the spectral range between 300 nm and 900 nm, and the liquid crystal cell having a first Bragg reflection wavelength, when the applied voltage is modulated at a frequency comprised in an intermediate frequency range which is above a cross-over frequency and below a high frequency limit, the first Bragg reflection wavelength being different from the reference Bragg reflection wavelength and the cholesteric liquid crystal mixture being non-scattering both in the reference Bragg reflection mode and in the first Bragg reflection mode.