A display device is provided. The display device includes a display panel including a light-exiting side, and a birefringent structure disposed at the light-exiting side of the display panel. A plane of the birefringent structure is parallel to a plane of the display panel. When the display device is in a display stage, the birefringent structure and the display panel are configured with a relative rotation at a plane parallel to the plane of the birefringent structure.

A display device is provided. The display device includes a display panel including a light-exiting side, and a birefringent structure disposed at the light-exiting side of the display panel. A plane of the birefringent structure is parallel to a plane of the display panel. When the display device is in a display stage, the birefringent structure and the display panel are configured with a relative rotation at a plane parallel to the plane of the birefringent structure.

The optical element is an optical element comprising a first optically anisotropic layer which is a cured layer of a liquid crystal composition containing a first disk-like liquid crystal compound, in which the optical element has a liquid crystal alignment pattern in which an optical axis of the first disk-like liquid crystal compound is parallel to a surface of the first optically anisotropic layer, the first optically anisotropic layer is disposed along at least one direction in a plane of the first optically anisotropic layer, and orientation of the optical axis of the first disk-like liquid crystal compound rotationally changes continuously, and the orientation of the optical axis rotates by 180 with a period of 0.5m to 5m.

A beam deflector includes a first wavelength selective polarizer configured to convert a polarization state of light in a first wavelength band into a first polarization state, a first liquid crystal deflector including liquid crystal molecules and an optical path change surface to deflect light incident from the first wavelength selective polarizer, and a controller configured to control the first liquid crystal deflector to adjust an angle of the first optical path change surface.

A phase difference film including: a phase difference thin film including at least two non-liquid crystal polymers, wherein the phase difference thin film satisfies refractive indexes of n.sub.xn.sub.y>n.sub.z and has a thickness direction phase difference per unit thickness of greater than or equal to about 80 nm/m, wherein n.sub.x denotes a refractive index of the phase difference thin film at a slow axis thereof, n.sub.y denotes a refractive index of the phase difference thin film at a fast axis thereof, and n.sub.z denotes a refractive index of the phase difference thin film in a direction perpendicular to the slow axis and the fast axis thereof, and wherein an average light transmittance in a wavelength region of about 360 nm to about 740 nm is greater than or equal to about 88%, and a display device including the same.

An object is to provide a phase difference compensation element capable of improving the contrast of a liquid crystal display device while solving the problems of a high cost, an increase in the lead time, an increase in the mounting space, and the durability. A phase difference compensation element includes: a phase difference imparting and reflection preventing layer; a first birefringence layer and a second birefringence layer in which an angle of a corner formed by a main axis of refractive index anisotropy and a surface of a transparent substrate is not 90 degrees; a third birefringence layer in which an angle of a corner formed by a main axis of refractive index anisotropy and the surface of the transparent substrate is 0 degrees, wherein, when segments acquired when the main axes of the first, second, and third birefringence layers are projected onto the transparent substrate are respectively denoted by a segment A, a segment B, and a segment C, relations of the following (1) and (2) are satisfied. (1) The angle of the corner formed by the segment A and the segment B is 45 degrees or more and 70 degrees or less. (2) The segment A and the segment C are approximately parallel with each other, or the segment B and the segment C are approximately parallel with each other.

The invention provides a new technique for improving the contrast in a liquid-crystal display device having a liquid crystal layer that is formed of pretilted liquid crystal molecules having a negative dielectric constant anisotropy. A liquid-crystal display device according to an aspect of the invention includes a liquid crystal panel in which a phase-difference compensation layer including a C plate is formed, and a phase-difference compensation member disposed on the outside of the liquid crystal panel and including an O plate or an A plate. The liquid crystal panel includes an opposing substrate, a liquid crystal layer formed of pretilted liquid crystal molecules having a negative dielectric constant anisotropy, and an element substrate.

Embodiments of the present disclosure provide a liquid crystal display panel and a display device. The panel comprises a first and second polarizers, a liquid crystal layer, a first and second optical compensation films. The liquid crystal layer is disposed between the opposite first and second polarizers; the first optical compensation film is located between the first polarizer and the liquid crystal layer, and an optical axis of the first optical compensation film is parallel to a plane where the first optical compensation film is in; and the second optical compensation film is located between the first and second polarizers, an optical axis of the second optical compensation film is parallel to a plane where the second optical compensation film is in and perpendicular to the optical axis of the first optical compensation film, and in-plane retardations of the first and second optical compensation films are equal.

The phase difference compensation element that is used in combination with a liquid crystal cell provided with a liquid crystal layer in which an optical axis of liquid crystal molecules is inclined and that compensates for a phase difference of light generated in the liquid crystal layer, the phase difference compensation element includes a substrate and a phase difference film having at least one oblique vapor deposition layer on at least one substrate surface of the substrate, and the phase difference compensation element is disposed in an aspect in which an intersecting angle between a slow-axis direction of the phase difference film and a fast-axis direction of the liquid crystal layer, which is a direction perpendicular to a direction in which the inclined optical axis of the liquid crystal molecules is projected onto the substrate surface, is ?25? to +25?.

Provided is a phase difference plate including a substrate and a phase difference film which is an oblique film, in which, in a case where three principal refractive indices in a biaxial refractive index ellipsoid exhibiting the refractivity anisotropy are defined as nx, ny, and nz, Conditional Expression (1) is satisfied, and in a case where an incidence angle in a direction inclined to the X-axis side with respect to the normal line is regarded as positive, a phase difference ratio Re(30) ratio, which is a ratio of Re(+30) of a phase difference of the incidence light with an incidence angle of +30 to Re(30) of a phase difference of the incidence light with an incidence angle of 30, satisfies Conditional Expression (2).
ny>nx>nz(1)
Re(30) ratio=Re(30)/Re(30)=1.1 to 4.0(2)