Optical film stacks are described. More particularly, optical film stacks including a half-wave retardation layer are described. Achromatic half-wave retardation layers, including achromatic half-wave layers formed from a quarter-wave and a three-quarters-wave retardation layer, are described. Film stacks including reflective polarizers tuned to reduce wavelength dispersion of the half-wave retardation layer are also described.

Provided are a polarizing plate and an optical display device including same, the polarizing plate comprising a polarizing film and a contrast ratio enhancement layer formed on a light-emitting surface of the polarizing film, wherein the contrast ratio enhancement layer comprises: a first resin layer including a pattern unit having one or more engraved patterns and a flat portion formed between the engraved patterns; and a second resin layer directly formed on the pattern unit, wherein the engraved patterns have a base angle of approximately 75° to approximately 90°, the pattern unit satisfies formula 1, the first resin layer has a refractive index larger than that of the second resin layer, and the first resin layer includes a dye of which the maximum absorption wavelength is approximately 550 nm to approximately 620 nm.

As for a method for manufacturing a light valve and a light valve manufactured thereby of the present invention, the light valve is composed of a film 1 in which a light-polarizing suspension 3, containing: 5 to 20 wt % of light polarization variable particles 4 showing light polarization characteristics and having a size of 0.2 to 0.5 μm; 2 to 10 wt % of a dispersion aid; and 80 to 93 wt % of a suspension agent which is a plasticizer, is dispersed in the form of fine droplets 5 in a polymer resin 2 having excellent adhesive strength to a substrate 9, wherein the ratio of the droplets 5 and the polymer resin 2 is 0.5 to 1:1, the polymer resin 2 is polyvinyl butyral, and regarding the suspension agent constituting the light-polarizing suspension 3, at least one plasticizer among trioctyl trimellitate- or trioctyldecyl trimellitate-based plasticizers is used as the suspension agent.

Provided is an optically anisotropic film having favorable black tightness when the optically anisotropic film is disposed on a display element as a circularly polarizing plate in combination with a polarizer and an obtained display device is viewed from an oblique direction; as well as a circularly polarizing plate and a display device. The optically anisotropic film is formed of a composition containing a non-colorable lyotropic liquid crystal compound, in which an Nz factor of the optically anisotropic film satisfies a relationship of Expression (1) 0.40≤Nz factor≤0.60 and the optically anisotropic film satisfies a relationship of Expression (2) 0.60≤Re(450)/Re(550)≤0.90. In Expressions (1) and (2) Re(450) represents an in-plane retardation of the optically anisotropic film at a wavelength of 450 nm, and Re(550) represents the in-plane retardation of the optically anisotropic film at a wavelength of 550 nm.

A reflective polarizer includes a plurality of first layers disposed on a plurality of polymeric second layers. Each of at least 30% of the first layers includes at least 30% by weight of an inorganic material. For an incident light incident in a plane and a first incident angle, the reflective polarizer and the first layers have respective average optical reflectances R3v and R1v in a visible wavelength range and respective average optical reflectances R3ir and R1ir in an infrared wavelength range, R1v<R3v and (R1ir−R3ir)>10%, when the incident light is polarized along a first direction; and for the visible wavelength range and for a second incident angle, the plurality of polymeric second layers has an average optical reflectance R2v(x) when the plane includes the first direction and an average optical reflectance R2v(y) when the plane includes a second direction, 5%<R2v(y)<R2v(x)<60%.

Optical film stacks are described. More particularly, optical film stacks including a half-wave retardation layer are described. Achromatic half-wave retardation layers, including achromatic half-wave layers formed from a quarter-wave and a three-quarters-wave retardation layer, are described. Film stacks including reflective polarizers tuned to reduce wavelength dispersion of the half-wave retardation layer are also described.

A display system is disclosed and includes a display and a reflective polarizer disposed on the display. For substantially normally incident light, for a primary wavelength λ.sub.b, the reflective polarizer transmits at least 60% of the incident light having a first polarization state x and reflects at least 60% of the incident light having an orthogonal second polarization state y. For each of a first wavelength λ.sub.uv and a second wavelength λ.sub.bg, 0<λ.sub.b-λ.sub.uv≤100 nm#and 0<λ.sub.bg-λ.sub.b≤100 nm, the reflective polarizer transmits at least 40% of the incident light for each of the first and second polarization states.

A polarizing plate and an optical display including the same are provided. A polarizing plate includes: a polarizing film; a first base layer; and a pattern layer, the first base layer and the pattern layer being sequentially arranged on a light exit surface of the polarizing film, and the pattern layer includes a first layer and a second layer sequentially arranged on the first base layer, the first layer having a higher index of refraction than the second layer, and the first layer includes a patterned portion at at least a portion thereof facing the second layer, the patterned portion including at least two optical patterns and a flat section between optical patterns of the at least two optical patterns that are adjacent to each other.

An optical stack for a display device includes multiple layers that are incorporated into a display device that further includes a display panel. The optical stack includes a resin layer, an alignment film, an optical compensation layer, a polarizer, and a hard coat layer that are stacked in this order from a panel side. The optical stack is formed by preparing and coating a solution for each layer, and then curing and otherwise treating each layer as warranted for a particular layer, in turn to form the optical stack.

An optical stack including a first reflective polarizer adhered to a second reflective polarizer is described. For normally incident light and each wavelength in a same predetermined wavelength range, each reflective polarizer transmits at least 80% of light polarized along a pass axis of the reflective polarizer and reflects at least 90% of light polarized along an orthogonal block axis of the reflective polarizer. Each reflective polarizer includes a plurality of polymeric interference layers reflecting and transmitting light primarily by optical interference in the predetermined wavelength range. A separation between the two polymeric interference layers in the plurality of polymeric interference layers farthest from each other are d1 and d2 for the respective first and second reflective polarizers, d1 is at least 20% less than d2. Polarizing beam splitters including the optical stack and optical systems including the polarizing beam splitter are described.