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.

Embodiments relate to an optical film and a liquid crystal display device comprising the same. More specifically, the embodiments relate to an optical film that is excellent in optical characteristics and has no polarization unevenness since it comprises a base layer that has a low in-plane retardation and a low thickness direction retardation and has an excellent adhesiveness by virtue of a proper level of surface tension, a process for preparing the same, and a liquid crystal display device comprising the same.

A display apparatus includes a plurality of light sources configured to emit light; a light guide plate having a first surface and a second surface, configured to spread light emitted from the plurality of light sources therein to emit light through the first surface; and a local dimming unit configured to reflect or scatter light emitted through the second surface of the light guide plate according to a location. The local dimming unit may include an electro-optical layer configured to change optical properties according to an electric field; a plurality of electrodes located on the same plane, configured to generate the electric field; and a controller configured to change a voltage applied to the plurality of electrodes according to an image.

A display panel includes a first substrate, an electrode layer, and a display medium layer. The electrode layer is disposed on the first substrate. The display medium layer is disposed on the electrode layer and includes a filler and liquid crystal capsules. The liquid crystal capsules are distributed in the filler, and the filler has a birefringence difference Δn in a range from 0.02 to 0.175.

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.

The display apparatus may comprise: a plurality of light sources for emitting light; a light guide plate, having a first surface and a second surface, for internally diffusing the light emitted from the plurality of light sources and emitting through the first surface; and a local dimming unit for reflecting or scattering, on the basis of location, the light emitted from the second surface of the light guide plate. Moreover, the local dimming unit may comprise: an electro-optic layer, the optical properties of which vary in accordance with an electric field; a plurality of electrodes located on the same plane and generating the electric field; and a control unit for varying the voltage applied to the plurality of electrodes in accordance with an image.

A privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. A birefringent surface relief diffuser structure is arranged to transmit light from the display with high transparency and provide diffuse reflection of ambient light to head-on display users. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss and with low diffusion, whereas off-axis light has reduced luminance and increased diffusion. Further, overall display reflectivity is reduced for on-axis reflections of ambient light, while reflectivity is increased for off-axis light. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction, increased frontal reflectivity and diffusion of ambient light. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

An optical device is provided that includes a first optical member made of a birefringent material and disposed so that an optical axis of the first optical member is neither parallel nor orthogonal to a direction in which incident light travels. Moreover, a second optical member made of a birefringent material is disposed so that an optical axis of the second optical member is neither parallel nor orthogonal to the direction in which the incident light travels. A third optical member is disposed between the first and second optical members and generates an optical path difference of {¼+m×(½)}×λ (m is an integer) between orthogonal polarization components of light emitted from the first optical member. At least one of the optical members is rotatable about an axis of the incident light.

A multi-conjugate filter (MCF) can be operated in both a single bandpass mode and a multiple bandpass mode. By applying different voltages to different channels of a MCF, the MCF can be used to filter light into (1) a single narrow spectral output or (2) a broad ranged “white light” spectral output.

The present application discloses a liquid crystal display apparatus and a fabricating method thereof, a back light and a fabricating method thereof. The liquid crystal display apparatus includes a base substrate; a liquid crystal layer; and an anisotropic grating on a side of the liquid crystal layer distal to the base substrate. The anisotropic grating includes a plurality of barriers and a plurality of slits arranged alternately. The anisotropic grating is configured to separate incident light into light of a first color, light of a second color, and light of a third color, and configured to emit the light of the first color, the light of the second color, and the light of the third color at different exit angles, respectively.