Abstract: Provided are a liquid crystal diffraction element that diffracts incident light while allowing transmission of the incident light and has wavelength selectivity, and a laminated diffraction element.

Abstract: Provided are an optical member in which emission of stray light to the outside can be suppressed and an image display apparatus. The optical member includes: a light guide element including a light guide plate and an incidence diffraction element and an emission diffraction element that are disposed on a main surface of the light guide plate; and a polarization element that blocks transmission of light leaking to a side of the emission diffraction element opposite to an emission side, wherein the emission diffraction element is a polarization diffraction element, the polarization element is disposed on the side of the emission diffraction element opposite to the emission side, and the polarization element is disposed at a position overlapping the emission diffraction element in a plane direction of the main surface of the light guide plate.

Abstract: Provided are a cholesteric liquid crystal layer that diffracts specific circularly polarized light in a specific wavelength range by transmission, and a method of forming the cholesteric liquid crystal layer. The cholesteric liquid crystal layer is obtained by immobilizing a cholesteric liquid crystalline phase, 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, in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, bright portions and dark portions derived from the cholesteric liquid crystalline phase are tilted at 80° or more with respect to a main surface of the cholesteric liquid crystal layer.

Abstract: An optical element includes a light guide plate, an incidence portion, and an emission portion, in which the incidence/emission portion includes an ?1 diffraction element having a diffraction period ?1, an ?2 diffraction element having a diffraction period ?2, and an ?3 diffraction element having a diffraction period ?3, “?1:?2:?3 = 1: 1/?2± 0.015: ½ ± 0.015” is satisfied, an angle between periodic directions of the ?1 diffraction element and the ?2 diffraction element and an angle between periodic directions of the ?2 diffraction element and the ?3 diffraction element is 45° or 135° (± 0.5°), and an angle between the periodic directions of the ?2 diffraction elements in the incidence portion and the emission portion is any one of 0°, 90°, 180°, or 270° (± 0.5°).

Abstract: Provided is a transmissive liquid crystal diffraction element having a large diffraction angle and a high diffraction efficiency.

Abstract: An object is to provide an optical element in which a wavelength dependence of refraction of transmitted light is small, and a light guide element including the optical element.

Abstract: Provided is an optical element that can display a clear image having no blurriness in AR glasses or the like. The optical element includes: a substrate; and a laminate that is provided on the substrate and where a plurality of liquid crystal layers obtained by aligning a liquid crystal compound are laminated, in which the liquid crystal layers have a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction, and in at least one of the liquid crystal layers, an arithmetic mean value of differences between maximum film thicknesses and minimum film thicknesses obtained by observing 10 cross-sections with a scanning electron microscope is 0.1 ?m or less.

Abstract: Provided are an optical element that can make the brightness of light emitted from a light guide plate uniform, a light guide element, and an image display device. The optical element includes a patterned cholesteric liquid crystal layer that is obtained by immobilizing a cholesteric liquid crystalline phase, in which the patterned 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 the patterned cholesteric liquid crystal layer has regions having different pitches of helical structures in a plane.

Abstract: Provided are a liquid crystal diffraction element having a high diffraction efficiency irrespective of diffraction angles, an optical element including the liquid crystal diffraction element, and an image display unit, a head-mounted display, a beam steering, and a sensor including the liquid crystal diffraction element or the optical element.

Abstract: Provided are a liquid crystal diffraction element which exhibits low scattering and high sharpness of diffracted light, and a method for producing the same.

Abstract: An object is to provide a liquid crystal diffraction element that has small wavelength dependence of diffraction efficiency and diffracts light having the same wavelength at the same angle, an optical element including the liquid crystal diffraction element, and an image display unit, a head-mounted display, a beam steering, and a sensor including the liquid crystal diffraction element or the optical element.

Abstract: Provided are an image display unit and a head-mounted display where the size is small, the light utilization efficiency is high, and a decrease in image quality is small. The image display unit includes: an image display apparatus; a polarization diffraction element that diffracts light emitted from the image display apparatus; and a polarizing plate that allows transmission of the polarized light diffracted by the polarization diffraction element and absorbs light not diffracted by the polarization diffraction element, in which the polarization diffraction element is a polarization diffraction lens having a lens function, and in a case where a focal length of the polarization diffraction lens is represented by f and a distance between the image display apparatus and the polarization diffraction lens is represented by d, d?f is satisfied.

Abstract: An object of the present invention is to provide a light deflection device having a simple structure suitable for reducing the size and weight where a deflection angle can be increased. The object can be achieved with a light deflection device including: a light deflection element that deflects incident light in one direct to be emitted; a driving unit that drives the light deflection element; and a diffraction element that is disposed on a light emission side of the light deflection element in which a periodic structure pitch gradually changes from a center of deflection from the light deflection element toward an outside.

Abstract: An optical element comprising: a cholesteric liquid crystal layer obtained by cholesteric alignment of a liquid crystal compound, in which the cholesteric liquid crystal layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction, a helical pitch of a helical axis direction in the cholesteric alignment gradually changes in a thickness direction of the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer has a peak of reflection at each of a first wavelength ? and a second wavelength ?/2.

Abstract: An optical element includes a cholesteric liquid crystal layer obtained by cholesterically aligning a liquid crystal compound, in which the cholesteric liquid crystal layer has a region where a refractive index nx in a slow axis direction and a refractive index ny in a fast axis direction in a plane satisfy nx>ny, a helical axis of the cholesteric alignment is parallel to a thickness direction of the cholesteric liquid crystal layer, and a helical pitch in the cholesteric alignment gradually changes in the thickness direction of the cholesteric liquid crystal layer.

Abstract: A transmissive liquid crystal diffraction element includes a rod-like liquid crystal layer where a rod-like liquid crystal compound is aligned and a disk-like liquid crystal layer where a disk-like liquid crystal compound is aligned that are alternately laminated, in which each of the liquid crystal layers has a predetermined liquid crystal alignment pattern, rotation directions of optical axes in the liquid crystal alignment patterns are the same, single periods of the liquid crystal alignment patterns are the same, a thickness direction retardation |Rth| of each of the liquid crystal layers is 65 nm or less, and at an interface between the liquid crystal layers, longitudinal directions of the liquid crystal compounds match with each other.

Abstract: Provided are a liquid crystal diffraction element that can make the brightness of light emitted from a light guide plate uniform and a light guide element. The liquid crystal diffraction element includes: an optically-anisotropic layer that is formed of a composition including a liquid crystal compound, in which the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound continuously rotates in at least one in-plane direction, and a diffraction efficiency of the optically-anisotropic layer increases from one side to another side in the one in-plane direction.

Abstract: Provided are: a sensor that is used as a distance-measuring sensor or the like and where a high SN ratio can be obtained and high-accuracy measurement can be performed even in a case where an environmental temperature changes; and a band pass filter that is used for the sensor. The sensor includes: a light source; a band pass filter; and a light-receiving element, in which the band pass filter includes a band pass layer and a support that supports the band pass layer, and in a case where a thermal expansion coefficient of the band pass layer is represented by ?1, an elastic modulus of the band pass layer is represented by E1, a thermal expansion coefficient of the support is represented by ?2, and an elastic modulus of the support is represented by E2, ?1>?2 and E1<E2 are satisfied.

Abstract: An optically anisotropic film is formed of a liquid crystal composition including a liquid crystal compound and has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction of the optically anisotropic film, and the optically anisotropic film satisfies predetermined requirements.

Abstract: An optical element includes an optically-anisotropic layer that is formed of a liquid crystal composition including a liquid crystal compound having a polymerizable group, in which a ratio of a bend elastic constant K33 to a splay elastic constant K11 in the liquid crystal composition satisfies 0.8?K33/K11?1.2 at any temperature of a nematic temperature range, and the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction.