Provided is a liquid crystal display device having high luminance and high CR in a front direction and especially useful as a head-mounted liquid crystal display device, for example. The liquid crystal display device includes: a liquid crystal panel; an optical element; and a backlight, arranged in this order from a viewing surface side. The optical element includes a first polarizer, a retardation layer, and a second polarizer. The first polarizer, the retardation layer, and the second polarizer are arranged in this order from the viewing surface side. The first polarizer and the second polarizer are reflection polarizers. A reflection axis of the first polarizer and a reflection axis of the second polarizer are parallel to each other. In oblique directions at azimuths of 0°, 45°, and 90° at a polar angle of 60°, a polarization state of light incident on the first polarizer is elliptical polarization.

Provided are an optical element that can achieve both color difference control and luminance reduction at an oblique viewing angle, and a liquid crystal display device including the optical element and having excellent display quality. The optical element includes: a first polarizer; a first phase difference layer; a second phase difference layer; and a second polarizer, the first polarizer, the first phase difference layer, the second phase difference layer, and the second polarizer being arranged in the stated order, the first phase difference layer satisfying the formula nx>ny≈nz, the second phase difference layer satisfying the formula nz>nx≈ny, the first polarizer and the second polarizer being linear polarizers, transmission axes of the first polarizer and the second polarizer being parallel to each other, a slow axis of the first phase difference layer being orthogonal to a polarization axis of the first polarizer.

A liquid crystal display device includes, in order from an observation surface side to a hack surface side, a thin film transistor substrate including a color filter layer, a pair of electrodes, and a metal wiring line, a liquid crystal layer containing liquid crystal molecules that are horizontally aligned to the thin film transistor substrate and in which alignment of the liquid crystal molecules is changed due to an electric field generated by applying a voltage to the pair of electrodes, a counter substrate, and a backlight, in which the counter substrate includes a reflective layer disposed outside the pixel area and reflecting incident light from the backlight to the back surface side, the pair of electrodes are a first electrode having a planar shape and a second electrode provided with a and the color filter layer is disposed on the observation surface side of the second electrode.

The polarizing plate laminate according to an exemplary embodiment of the present disclosure includes: a polarizer; an adhesive agent layer or a bonding agent layer provided on the polarizer; a viewing angle compensation film provided on the adhesive agent layer or the bonding agent layer; and a base film provided on the viewing angle compensation film.

The liquid crystal display device includes: a first polarizer having a first transmission axis; a liquid crystal panel; a second polarizer having a second transmission axis; a biaxial retarder having a slow axis parallel to the second transmission axis; a third polarizer having a third transmission axis parallel to the second transmission axis; and a backlight, a back side polarizer portion that includes the second polarizer, the biaxial retarder, and the third polarizer satisfying the following formula (1): ΔYI.sub.2=YI.sub.2′− YI.sub.2<0 (1) wherein YI.sub.2′ represents a yellowness index in observation from an oblique direction, YI.sub.2 represents a yellowness index in observation from a front direction, and ΔYI.sub.2 represents a difference between YI.sub.2′ and YI.sub.2, wherein the front direction represents a direction at a 0° polar angle and the oblique direction represents a direction at a 60° polar angle and a 45° azimuth.

According to one embodiment, a display device includes a display panel that includes a display portion including pixels and a non-display portion including an opening, an illumination device, and a color separation element provided between the display panel and the illumination device. The color separation element includes a first element overlapping the pixel and a second element overlapping the opening, the first element separates illumination light from the illumination device into light of a plurality of colors and irradiates the pixel with the light, and the second element separates illumination light from the illumination device into light of a plurality of colors and irradiates the opening with the light.

The liquid crystal display device includes: a first polarizer having a first transmission axis; a liquid crystal panel; a second polarizer having a second transmission axis; a biaxial retarder having a slow axis parallel to the second transmission axis; a third polarizer having a third transmission axis parallel to the second transmission axis; and a backlight, a back side polarizer portion that includes the second polarizer, the biaxial retarder, and the third polarizer satisfying the following formula (1): ΔYI.sub.2=YI.sub.2′− YI.sub.2<0 (1) wherein YI.sub.2′ represents a yellowness index in observation from an oblique direction, YI.sub.2 represents a yellowness index in observation from a front direction, and ΔYI.sub.2 represents a difference between YI.sub.2′ and YI.sub.2, wherein the front direction represents a direction at a 0° polar angle and the oblique direction represents a direction at a 60° polar angle and a 45° azimuth.

A liquid crystal display device includes: a first liquid crystal cell; a second liquid crystal cell disposed in a backlight side; and a first optical sheet and a second optical sheet both having an identical layer structure. The first optical sheet is disposed on a front surface side of the first liquid crystal cell and the second optical sheet is disposed on a back surface side of the second liquid crystal cell, or vice versa.

The present invention provides an optical sheet for a light guide plate type liquid crystal display, including a low refractive index layer having an extremely low refractive index. The optical sheet A12 for a light guide plate type liquid crystal display (1000) according to the present invention includes a first optical film (light guide plate) (1010), a low refractive index layer (20), and a second optical film (reflection plate) (1020) laminated in this order, and the low refractive index layer (20) has a refractive index of 1.25 or less.

A liquid crystal display apparatus having improved viewing angle characteristics in a region vertically asymmetrical. A liquid crystal display apparatus of the present invention includes: a liquid crystal cell including a liquid crystal layer containing liquid crystal molecules aligned in homogeneous alignment under a state in which an electric field is absent; a first polarizer arranged on a viewer side of the liquid crystal cell; a second polarizer arranged on a back surface side of the liquid crystal cell; a first optical compensation layer arranged between the liquid crystal cell and the first polarizer; and a second optical compensation layer arranged between the liquid crystal cell and the first optical compensation layer. A refractive index nz.sub.1 in a thickness direction of the first optical compensation layer is less than 1.5187, and a refractive index nz.sub.2 in a thickness direction of the second optical compensation layer is less than 1.5340.