A retardation film is provided. The retardation film comprises a water-soluble polymer matrix and at least a water-soluble dichroic dye dispersed in the water-soluble polymer matrix. The water-soluble dichroic dye has a molecular long-axis aligned along a stretching direction of the water-soluble polymer matrix. The water-soluble dichroic dye has a maximum absorption wavelength between 550 nm and 650 nm, and has a dichroic ratio greater than 10 at the maximum absorption wavelength. The refractive index and the corresponding retardation value of the retardation film in long-wavelength band can be adjusted individually by adding the water-soluble dichroic dye with the maximum absorption wavelength between 550 nm and 650 nm in the water-soluble polymer matrix and arranging the water-soluble dichroic dye in an order. Therefore, reverse wavelength dispersion is generated.

Provided are a polarizing plate and an optical display device comprising same, the polarizing plate comprising: a polarizer; and a first phase difference layer, a second phase difference layer and a third phase difference layer which are sequentially stacked on the lower surface of the polarizer. The first phase difference layer comprises a positive C phase difference layer. The second phase difference layer has positive wavelength dispersibility and an in-plane phase difference of approximately 200 nm to 280 nm in a wavelength of 550 nm. The third phase difference layer has positive wavelength dispersibility and an in-plane phase difference of approximately 80 nm to 145 nm in a wavelength of 550 nm. When the absorption axis of the polarizer is 0°, the angle formed by the slow axis of the second phase difference layer is approximately +14° to +24° or approximately −24° to −14°, and the angle formed by the slow axis of the third phase difference layer is approximately +79° to +89° or approximately −89° to −79°.

Backlighting device for a screen for a television, mobile phone or the like, wherein the backlighting device comprises: a first light source adapted to emit light having a peak wavelength between 600 and 630 nm; a second light source adapted to emit light having a peak wavelength between 510 and 530 nm; a third light source adapted to emit light having a peak wavelength between 440 and 460 nm; wherein the light emitted by one of the light sources has a bandwidth of less than 15 nm, preferably less than 10 nm, more preferably less than 5 nm.

An optical film is an optical film in which a cholesteric liquid crystalline phase is fixed and a helical axis of the cholesteric liquid crystalline phase is aligned in an in-plane uniaxial direction, and an Nz is 0.2 to 0.75.

There is provided a display device exhibiting a good color reproducibility, even when observed through polarized sunglasses. A display device comprises a polarizer a and an optical film X on a surface on a light emitting surface side of a display element, wherein L.sub.1, which is the light incident vertically on the optical film X, among light incident on the optical film X from the display element side, satisfies a specific condition, and L.sub.2, which is the light emitting vertically from the light emitting surface side of the optical film X, and passing through a polarizer b having the absorption axis parallel to the absorption axis of the polarizer a, satisfies a specific condition.

Backlighting device for a screen for a television, mobile phone or the like, which includes a first light source adapted to emit light having a peak wavelength between 600 and 630 nm; a second light source adapted to emit light having a peak wavelength between 510 and 530 nm; a third light source adapted to emit light having a peak wavelength between 440 and 460 nm; and the light emitted by one of the light sources has a bandwidth of less than 15 nm, preferably less than 10 nm, more preferably less than 5 nm.

A reflective display panel and a display device are provided. The reflective display includes: a first liquid crystal cell including a first substrate and a second substrate oppositely arranged to each other, and a first liquid crystal layer between the first substrate and the second substrate; a plurality of pixel units on the first substrate, where each pixel unit includes a first sub-pixel unit and a second sub-pixel unit; an optical structure, arranged at a light-emitting side of the first liquid crystal cell and covering the pixel units.

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.

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.

The present application relates to a retardation film including a composition or a cured product thereof, the composition comprising: an acrylate-based resin having a glass transition temperature (Tg) of 120° C.; or more; a retardation adjusting agent comprising a styrene monomer; and a triazine-based birefringence adjusting agent, in which the triazine-based birefringence adjusting agent is included in an amount of more than 5 parts by weight and 15 parts by weight or less, based on 100 parts by weight of the acrylate-based resin; a polarizing plate comprising the same, and a liquid crystal display device comprising the same.