Provided are an optical element with which reflected light in a narrower wavelength range can be obtained and a wavelength selective filter and a sensor including the same optical element. The optical element includes 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 a liquid crystal compound changes while continuously rotating in at least one in-plane direction, and the cholesteric liquid crystal layer has a region where a refractive index nx in an in-plane slow axis direction and a refractive index ny in an in-plane fast axis direction satisfy nx>ny.

An optical device is provided. The optical device includes a first optical element configured to output an elliptically polarized light having one or more predetermined polarization ellipse parameters. The optical device also includes a second optical element including a birefringent material with a chirality, and configured to receive the elliptically polarized light from the first optical element and reflect the elliptically polarized light as a circularly polarized light.

An optical element is provided. The optical element includes an optical film including a birefringent material having a chirality. Optically anisotropic molecules of the birefringent material disposed adjacent a first surface of the optical film are configured with a first pretilt angle in a range of greater than 10° and less than 80°, or in a range of greater than −80° and less than −10°. Optically anisotropic molecules of the birefringent material disposed adjacent a second surface of the optical film opposing the first surface are configured with a second pretilt angle in the range of greater than 10° and less than 80°, or in the range of greater than −80° and less than −10°.

A liquid crystal display device including, sequentially in the following order: a light source unit, a rear side polarizer, a liquid crystal cell, a front side polarizer, and a viewing angle expansion film. Alternatively, a liquid crystal display device including, sequentially in the following order: a light source unit, a rear side polarizer, a liquid crystal cell, a viewing angle expansion film, and a front side polarizer. The liquid crystal display device optionally includes a rear side optical film provided between the rear side polarizer and the liquid crystal cell; and a front side optical film provided between the front side polarizer and the liquid crystal cell.

An anti-glare mirror with an image display function includes, in this order: an image display device; a circular polarization reflection layer A; a liquid crystal cell; and a linear polarizing plate, in which a phase difference layer such as a ¼ wavelength plate is provided between the circular polarization reflection layer A and the linear polarizing plate, and the circular polarization reflection layer A has a cholesteric liquid crystal layer obtained by curing a coating layer of a liquid crystal composition containing a polymerizable liquid crystal compound.

Each of a mirror surface display device and a light reflecting member includes a support member having an optical thin film thereon, a broadband selective reflection film and a display in this order; the optical thin film being formed on a surface of the support member facing the broadband selective reflection film; and the broadband selective reflection film being a film selectively transmitting one of clockwise circularly polarized light and counterclockwise circularly polarized light, and selectively reflecting the other polarized light, and having cholesteric regularity.

The present invention provides a viewing system capable of providing varying visual effects with a simpler configuration. In addition, the present invention also provides a display device, a stage installation, and a polymerizable liquid crystal composition. A viewing system according to the present invention is a viewing system for viewing an object to be irradiated including a light source unit, and the object to be irradiated with light emitted from the light source unit, in which the object to be irradiated includes a member, and a first circularly polarized light reflecting layer that is arranged on the member and reflects either right-handed circularly polarized light or left-handed circularly polarized light, the light source unit is capable of emitting light to be switchable between either right-handed circularly polarized light or left-handed circularly polarized light that is reflected by the first circularly polarized light reflecting layer or natural light, and circularly polarized light having a revolution direction opposite to a revolution direction of the circularly polarized light reflected by the first circularly polarized light reflecting layer, and color of the object to be irradiated is changed by switching light emitted from the light source unit.

Provided are an optical laminate in which a large diffraction angle can be obtained, a light guide element, and an AR display device. The optical laminate includes, in the following order: a first optically-anisotropic layer that is formed of a 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 continuously rotates in at least one in-plane direction; a phase difference layer; and a patterned cholesteric liquid crystal layer that is formed of a 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 continuously rotates in at least one in-plane direction, the liquid crystal compound being cholesterically aligned, in which in the first optically-anisotropic layer and the patterned cholesteric liquid crystal layer, the one in-plane directions in which the direction of the optical axis derived from the liquid crystal compound continuously rotates are the same, and rotation directions of the direction of the optical axis derived from the liquid crystal compound in the one in-plane direction are the same.

Provided are an optical laminate in which a large diffraction angle can be obtained, a light guide element, and an AR display device. The optical laminate includes, in the following order: a first optically-anisotropic layer that is formed of a 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; a cholesteric liquid crystal layer that is obtained by immobilizing a cholesteric liquid crystalline phase; and a second optically-anisotropic layer that is formed of a 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 continuously rotates in at least one in-plane direction, in which in the first optically-anisotropic layer and the second optically-anisotropic layer, the one in-plane directions in which the direction of the optical axis derived from the liquid crystal compound continuously rotates are the same, and rotation directions of the direction of the optical axis derived from the liquid crystal compound in the one in-plane direction are the same.

Each of a mirror surface display device and a light reflecting member includes a support member having an optical thin film thereon, a broadband selective reflection film and a display in this order; the optical thin film being formed on a surface of the support member facing the broadband selective reflection film; and the broadband selective reflection film being a film selectively transmitting one of clockwise circularly polarized light and counterclockwise circularly polarized light, and selectively reflecting the other polarized light, and having cholesteric regularity.