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.

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.

Techniques are described for operating an optical system. In some embodiments, light associated with a world object is received at the optical system. Virtual image light is projected onto an eyepiece of the optical system. A portion of a system field of view of the optical system to be at least partially dimmed is determined based on information detected by the optical system. A plurality of spatially-resolved dimming values for the portion of the system field of view may be determined based on the detected information. The detected information may include light information, gaze information, and/or image information. A dimmer of the optical system may be adjusted to reduce an intensity of light associated with the world object in the portion of the system field of view according to the plurality of dimming values.

A first object of the present invention is to provide a method for producing a cholesteric liquid crystal layer, which can produce a cholesteric liquid crystal layer whose reflection surface is not parallel to the substrate surface by a simple method. A second object of the present invention is to provide a cholesteric liquid crystal layer, and an optically anisotropic body and a reflective layer, each of which includes the cholesteric liquid crystal layer. A third object of the present invention is to provide a liquid crystal composition capable of forming the cholesteric liquid crystal layer. A fourth object of the present invention is to provide a cured product, an optically anisotropic body, and a reflective layer, each of which is formed of the liquid crystal composition.

The method for producing a cholesteric liquid crystal layer of the present invention includes a step 1 of forming a composition layer satisfying the following condition 1, the following condition 2, or the following condition 3 on a substrate, using a liquid crystal composition including a liquid crystal compound; and a step 2 of subjecting the composition layer to a treatment for cholesterically aligning the liquid crystal compound in the composition layer to form a cholesteric liquid crystal layer.

Condition 1: at least a part of the liquid crystal compound in the composition layer is tilt-aligned with respect to a substrate surface

Condition 2: the liquid crystal compound is aligned such that a tilt angle of the liquid crystal compound in the composition layer continuously changes along a thickness direction;

Condition 3: at least a part of the liquid crystal compound in the composition layer is vertically aligned with respect to the substrate surface.

A reflective-type color display according to the present disclosure includes a lower substrate and an upper substrate, a polarization plate positioned on an outer surface of the upper substrate, a plurality of helical photonic crystals arranged between the lower substrate and the upper substrate and having different reflection properties of light in the visible region, and a tunable wave plate positioned on the plurality of helical photonic crystals to control the reflection intensity by continuously changing the phase retardation. According to an embodiment, it is possible to simultaneously achieve the features of three primary colors, analog grey levels, high resolution, and fast response through the separation of the function of color reflection from the intensity tuning capability of the photonic crystal, beyond the limitation of existing reflective-type display technology.

The invention provides a reflection film in which generation of side lobes derived from a cholesteric liquid crystalline layer is suppressed. A reflection film of the invention includes: a first cholesteric liquid crystalline layer which is formed of a composition including a first liquid crystal compound; and a second cholesteric liquid crystalline layer which is disposed at least on one surface of the first cholesteric liquid crystalline layer and formed of a composition including a second liquid crystal compound, in which a helical pitch length of the first cholesteric liquid crystalline layer is constant, a birefringence n.sub.2 of the second liquid crystal compound is smaller than a birefringence n.sub.1 of the first liquid crystal compound, and a helical pitch number of the second cholesteric liquid crystalline layer is a half or less of a helical pitch number of the first cholesteric liquid crystalline layer.

A mirror cell and a display device are disclosed. The mirror cell includes a lower substrate, which includes a lower alignment film and a lower electrode, an upper substrate, which opposes the lower substrate and includes an upper alignment film and an upper electrode, a liquid crystal layer, which is disposed between the lower alignment film and the upper alignment film and includes a cholesteric liquid crystal and a reactive liquid crystal, and a reactive layer, which is disposed between the upper alignment film and the liquid crystal layer and includes a same kind of reactive liquid crystals as the reactive liquid crystal in the liquid crystal layer.

According to the present invention, there is provided a plurality of protruding portions that are formed on one surface of the support and have inclined surfaces parallel to each other; a cholesteric liquid crystal layer that is formed on each of the inclined surfaces of the protruding portions; and an overcoat layer that is laminated on the surface of the support on which the protruding portions are formed so as to cover the cholesteric liquid crystal layer, in which a normal line of each of the inclined surfaces of the protruding portions is parallel to a spiral axis of the cholesteric structure of the cholesteric liquid crystal layer, an angle formed between a normal line of a surface of the overcoat layer and the spiral axis of the cholesteric structure is 5 to 42, a difference in refractive index between the cholesteric liquid crystal layer and the protruding portion and a difference in refractive index between the cholesteric liquid crystal layer and the overcoat layer are 0.2 or less.

A louver film, a planar light source device, and a liquid crystal display device enables further improvement of directivity for visibility while light use efficiency is maintained and also enable improvement of viewing angle contrast and halo. The louver film includes a plurality of lenses which are arranged at a constant pitch on an emission side of a light source; a first support disposed on a side closer to the light source than the lenses and has a thickness greater than or equal to the pitch of the lenses and a refractive index of 1.5 or greater; and a light reflecting layer disposed on a side closer to the light source than the first support and has a reflectivity of 90% or greater and openings on optical axes of the plurality of lenses, and the opening ratio of each opening is in a range of 30% to 70%.