A display apparatus includes display unit and an optical compensation film. The display unit includes an upper polarizer. The optical compensation film is located at a side of the upper polarizer facing an external environment. The optical compensation film includes a linear polarizer. An absolute value of an axial angle difference between the linear polarizer and the upper polarizer is in a range from 0 degrees to 10 degrees.

Provided is an optical element including: a first liquid crystal cell; and a second liquid crystal cell, with no polarizing plate between the first and second liquid crystal cells. The first liquid crystal cell includes a first liquid crystal layer containing first liquid crystal molecules, and a first electrode pair which applies voltage to the first liquid crystal layer. The second liquid crystal cell includes a second liquid crystal layer containing second liquid crystal molecules, and a second electrode pair which applies voltage to the second liquid crystal layer. With no voltage applied to the first and second liquid crystal layers, an alignment direction of the first liquid crystal molecules near the second liquid crystal cell in the first liquid crystal layer is parallel to an alignment direction of the second liquid crystal molecules near the first liquid crystal cell in the second liquid crystal layer in a plan view.

The present application provides an optical film. By controlling transmittance of a liquid crystal layer comprising a radical initiator for the maximum absorption wavelength of the radical initiator, the present application can provide an optical film having a liquid crystal layer having excellent resistance to external stimuli and excellent optical properties. Such an optical film can have various forms and can be used in various fields.

An optical element is provided. The optical element includes a positive-C film including a liquid crystal (“LC”) layer. The optical element also includes a positive-A film. The optical element also includes a negative biaxial retardation film disposed between the positive-A film and the positive-C film.

An optical element is provided. The optical element includes a positive-C film including a liquid crystal (“LC”) layer. The optical element also includes a positive-A film. The optical element also includes a negative biaxial retardation film disposed between the positive-A film and the positive-C film.

Techniques are described for operating an optical system. In some embodiments, light associated with a world object is received at the optical system. Virtual image light is projected onto an eyepiece of the optical system. A portion of a system field of view of the optical system to be at least partially dimmed is determined based on information detected by the optical system. A plurality of spatially-resolved dimming values for the portion of the system field of view may be determined based on the detected information. The detected information may include light information, gaze information, and/or image information. A dimmer of the optical system may be adjusted to reduce an intensity of light associated with the world object in the portion of the system field of view according to the plurality of dimming values.

Techniques are described for operating an optical system. In some embodiments, light associated with a world object is received at the optical system. Virtual image light is projected onto an eyepiece of the optical system. A portion of a system field of view of the optical system to be at least partially dimmed is determined based on information detected by the optical system. A plurality of spatially-resolved dimming values for the portion of the system field of view may be determined based on the detected information. The detected information may include light information, gaze information, and/or image information. A dimmer of the optical system may be adjusted to reduce an intensity of light associated with the world object in the portion of the system field of view according to the plurality of dimming values.

A polymer being a product of reactants including a diamine and a monomer represented by Chemical Formula 1: ##STR00001##
wherein, in Chemical Formula 1, R.sup.1, R.sup.2, o, p, L.sup.1, A.sup.1, R.sup.a, m, and n are the same as defined in the detailed description.

A compound retarder that creates independent control of R.sub.e and R.sub.th. This can be done by forming a three-layer compound retarder, including a pair of matched −A-plates, combined with single +A-plate. The +A-plate is typically an MD-stretched film, with retardation that is specific to the in-plane requirements (R.sub.e) of the application. The pair of −A-plates have their optic axes crossed, such that R.sub.e=0, with an optic axis aligned parallel to the +A-plate. A single retardation value for the −A-plate can produce improved field-of-view performance over a broad range of R.sub.e values, making it a very practical means of universal compensation. While R.sub.th is typically associated with a single retarder, retarder stacks with a diverse range of optic-axis orientations can be considered to have a compound (or composite) R.sub.th value (R.sub.th.sup.c). The three-layer compound retarder has the practical benefit of enabling field-of-view compensation across a broad range of normal-incidence polarization transformations.

Provided is a polymerizable liquid crystal composition used for formation of an optically anisotropic film having excellent durability, an optically anisotropic film, an optical film, a polarizing plate, and an image display device. The polymerizable liquid crystal composition contains a polymerizable liquid crystal compound represented by Formula (1) and an acidic compound, in which a pKa of the acidic compound is more than −10 and 5 or less, and a content of the acidic compound is 20 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound. ##STR00001##