An object is to provide: a transparent screen having high transparency in which a hot spot caused by transmitted light can be reduced; and an image display system in which visibility of a screen is excellent and a hot spot is reduced by using the transparent screen. The object is achieved by the transparent screen including: a dot array in which dots obtained by immobilizing a cholesteric liquid crystalline phase are two-dimensionally arranged; and a layer that is obtained by immobilizing a cholesteric liquid crystalline phase.

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.

An object of the present invention is to provide a method for producing a reflective layer having an excellent diffuse reflectivity and a wide reflection wavelength range. Another object of the present invention is to provide a reflective layer having an excellent diffuse reflectivity and a wide reflection wavelength range.

The method for producing a reflective layer of the present invention includes: a step 1 of applying a composition selected from the group consisting of the following composition X and the following composition Y onto a substrate to form a composition layer; a step 2 of heating the composition layer to align a liquid crystal compound in the composition layer into a cholesteric liquid crystalline phase state; a step 3 of cooling or heating the composition layer in a cholesteric liquid crystalline phase state to reduce a helical pitch; and a step 4 of irradiating at least a partial region of the composition layer with light, between the step 1 and the step 2, between the step 2 and the step 3, or after the step 3, to photosensitize a chiral agent A or a chiral agent C in the composition layer. Composition X: a composition including a liquid crystal compound, a chiral agent A whose helical twisting power is changed upon light irradiation, and a chiral agent B whose helical twisting power is increased upon cooling or heating. Composition Y: a composition including a liquid crystal compound and a chiral agent C whose helical twisting power is changed upon light irradiation and whose helical twisting power is increased upon cooling or heating.

An object of the present invention is to provide a compound having a strong HTP and a high temperature dependence of HTP. In addition, another object is to provide a liquid crystal composition, a cured substance, an optical anisotropic boy, and a reflection film in which the above-described compound is used.

The compound of the present invention is represented by General Formula (1).

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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.

An image display device includes a wavelength conversion layer containing quantum dots and a light reflecting layer provided on an observer side with respect to the wavelength conversion layer. The light reflecting layer includes, in a reflection wavelength region, a peak wavelength of a light source that emits excitation light to be used for emission of the quantum dots. The light reflecting layer is a polarizing reflective layer.

Provided is a sensor having a high SN ratio. The sensor includes a light source, a band pass filter, and a light-receiving element, in which the band pass filter includes two cholesteric liquid crystal layers and a discontinuous layer disposed between the two cholesteric liquid crystal layers, in the two cholesteric liquid crystal layers, helical twisted directions and helical pitches are the same, and in a case where the discontinuous layer is a layer other than a cholesteric liquid crystal layer and a wavelength having a lowest reflectivity in a selective reflection wavelength range of the band pass filter is represented by m [nm], a thickness [nm] is in a range of 30(m/550) to 150(m/550).

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.

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 optical member includes: a substrate; and a dot formed on a surface of the substrate. The dot has wavelength selective reflecting properties, and a cholesteric structure which has a stripe pattern including bright and dark portions in a cross-sectional view of the dot when observed with a scanning electron microscope. A surface shape of the dot opposite to the substrate in a cross-section of the dot in a thickness direction has at least one inflection point. In the cross-section, an angle between a normal line perpendicular to a line, formed using a first dark portion from a surface of the dot opposite to the substrate, and the surface of the dot, is in a range of 70 to 90. A proportion of a retroreflective area of the optical member is high when observed after light irradiation from an oblique direction to a normal direction perpendicular to the optical member.