Abstract: A reflective film includes interior layers that selectively reflect light by constructive or destructive interference, the layers extending from a first to a second zone of the film. In the first zone, the layers operate substantially as a reflective polarizer; in the second zone they operate substantially as a mirror. The layers may thus provide a first reflective characteristic in the first zone wherein normally incident light of one polarization state is substantially reflected and normally incident light of an orthogonal polarization state is substantially transmitted, and a second reflective characteristic in the second zone wherein normally incident light of any polarization state is substantially reflected. The film may have a first thickness in the first zone that is substantially the same as a second thickness in the second zone. Alternatively, the second thickness may be substantially less than the first thickness. Related methods, articles, and systems are also disclosed.

Abstract: A reflective film includes interior layers arranged to selectively reflect light by constructive or destructive interference, the layers extending from a first zone to a second zone of the film. The film has a first thickness and the interior layers provide a first reflective characteristic in the first zone; the film has a second thickness and the interior layers provide a second reflective characteristic in the second zone. The difference between the first and second reflective characteristics is not substantially attributable to any difference between the first and second thicknesses, which difference may be zero. Rather, the difference in the reflective characteristics is substantially attributable to reduced birefringence of at least some of the interior layers in one zone relative to the other zone. The film may also incorporate absorbing agents to assist in the manufacture or processing of the film. Related methods and articles are also disclosed.

Abstract: Articles including post-formed multilayer optical films with layers of at least one strain-induced birefringent material, methods of manufacturing such articles by post-forming multilayer optical films, and multilayer optical films that are particularly well-suited to post-forming operations are disclosed. The articles, methods and multilayer optical films of the present invention allow for post-forming of multilayer optical films including strain-induced index of refraction differentials while retaining the desired optical properties of the multilayer optical films.

Abstract: A multilayered polymer film includes a first set of optical layers and a second set of optical layers. The first set of optical layers is made from a polyester which is often birefringent. The polyesters of the first set of optical layers typically have a composition in which 70-100 mol % of the carboxylate subunits are first carboxylate subunits and 0-30 mol % are comonomer carboxylate subunits and 70 to 100 mol % of the glycol subunits are first glycol subunits and 0 to 30 mol % of the glycol subunits are comonomer glycol subunits, where at least 0.5 mol % of the combined carboxylate and glycol subunits are comonomer carboxylate or comonomer glycol subunits. The multilayered polymer film may be used to form, for example, a reflective polarizer or a mirror.

Abstract: A method of forming an optical film results in a film having a useful central 60% portion with a caliper variation of about 5% or less of an average thickness of the film. The method includes selecting a draw ratio ? in a first in-plane stretch direction, setting an effective draw gap defined by a length L and a width W, and stretching a polymer film at the draw ratio and effective draw gap. The effective draw gap is set such that the stretching step fits into one of two regimes, the first regime referred to as a uniaxial regime and characterized by a ? equal to or less than about 1.0; and the second regime referred to as a planar extension regime and characterized by a ? equal to or greater than about 10.0. The disclosure also describes an optical film formed by the method.

Abstract: An article for use in light spreading includes a body having first and second surfaces, and first and second in-plane axes that are orthogonal with respect to each other and a third axis that is mutually orthogonal to the first and second in-plane axes in a thickness direction of the body. A portion of the first surface is a birefringent structured surface. The portion is structured such that, when the article receives a light signal within a particular range of wavelengths, the structured surface causes splitting the light signal into a plurality of divergent light signals. The article can be used for color mixing such as in a cavity providing a backlight for LCD devices or other display devices requiring a backlight.

Abstract: A method of making an optical film includes providing a film, substantially uniaxially orienting the film, and heat setting the oriented film. The film includes a polymeric material capable of developing birefringence.

Abstract: Methods and apparatuses are provided for the manufacture of coextruded polymeric multilayer optical films. The multilayer optical films have an ordered arrangement of layers of two or more materials having particular layer thicknesses and a prescribed layer thickness gradient throughout the multilayer optical stack. The methods and apparatuses described allow improved control over individual layer thicknesses, layer thickness gradients, indices of refraction, interlayer adhesion, and surface characteristics of the optical films. The methods and apparatuses described are useful for making interference polarizers, mirrors, and colored films that are optically effective over diverse portions of the ultraviolet, visible, and infrared spectra.

Abstract: Articles including post-formed multilayer optical films with layers of at least one strain-induced birefringent material, methods of manufacturing such articles by post-forming multilayer optical films, and multilayer optical films that are particularly well-suited to post-forming operations are disclosed. The articles, methods and multilayer optical films of the present invention allow for post-forming of multilayer optical films including strain-induced index of refraction differentials while retaining the desired optical properties of the multilayer optical films.

Abstract: Films having a structured surface with an engineered feature, such as prism grooves, to be used in displays having a backlight. The films can be arranged in a stack having one or more of the following: birefringent brightness enhancement films, non-birefringent brightness enhancement films, polarizers, diffusers, birefringent turning films, and non-birefringent turning films. Those films can be arranged in any order from the backlight to a viewer.

Abstract: A multilayered polymer film includes a first set of optical layers and a second set of optical layers. The first set of optical layers is made from a polyester which is often birefringent. The polyesters of the first set of optical layers typically have a composition in which 70-100 mol % of the carboxylate subunits are first carboxylate subunits and 0-30 mol % are comonomer carboxylate subunits and 70 to 100 mol % of the glycol subunits are first glycol subunits and 0 to 30 mol % of the glycol subunits are comonomer glycol subunits, where at least 0.5 mol % of the combined carboxylate and glycol subunits are comonomer carboxylate or comonomer glycol subunits. The multilayered polymer film may be used to form, for example, a reflective polarizer or a mirror.

Abstract: Modified copolyesters having relatively low refractive indices and relatively high glass transition temperatures are disclosed. These modified copolyesters can be used in forming one or more layers in an optical film, such as a multilayer polymer film.

Abstract: A multilayered polymer film includes a first set of optical layers and a second set of optical layers. The first set of optical layers is made from a polyester which is often birefringent. The polyesters of the first set of optical layers typically have a composition in which 70-100 mol % of the carboxylate subunits are first carboxylate subunits and 0-30 mol % are comonomer carboxylate subunits and 70 to 100 mol % of the glycol subunits are first glycol subunits and 0 to 30 mol % of the glycol subunits are comonomer glycol subunits, where at least 0.5 mol % of the combined carboxylate and glycol subunits are comonomer carboxylate or comonomer glycol subunits. The multilayered polymer film may be used to form, for example, a reflective polarizer or a mirror.

Abstract: Modified copolyesters having relatively low refractive indices and relatively high glass transition temperatures are disclosed. These modified copolyesters can be used in forming one or more layers in an optical film, such as a multilayer polymer film.

Abstract: An optical stack includes a first liquid crystal layer and a j-retarder disposed on the liquid crystal layer. The j-retarder includes a simultaneous biaxally stretched polymeric film being substantially non-absorbing and non-scattering for at least one polarization state of visible light. The j-retarder has x, y, and z orthogonal indices of refraction where at least two of the orthogonal indices of refraction are not equal, an in-plane retardance being 100 nm or less and an out-of-plane retardance being 50 nm or greater.

Abstract: Modified copolyesters having relatively low refractive indices and relatively high glass transition temperatures are disclosed. These modified copolyesters can be used in forming one or more layers in an optical film, such as a multilayer polymer film.

Abstract: A method of forming an optical film results in a film having a useful central 60% portion with a caliper variation of about 5% or less of an average thickness of the film. The method includes selecting a draw ratio ? in a first in-plane stretch direction, setting an effective draw gap defined by a length L and a width W, and stretching a polymer film at the draw ratio and effective draw gap. The effective draw gap is set such that the stretching step fits into one of two regimes, the first regime referred to as a uniaxial regime and characterized by a ? equal to or less than about 1.0; and the second regime referred to as a planar extension regime and characterized by a ? equal to or greater than about 10.0. The disclosure also describes an optical film formed by the method.

Abstract: A method of forming an optical film includes stretching a polymer film in first draw gap of a first length along a machine direction, at a first draw ratio; and further stretching the polymer film in second draw gap along a machine direction, wherein the step of stretching in the first draw gap is isolated from the step of stretching in the second draw gap.

Abstract: An exemplary roll of film includes an oriented optical film comprising a birefringent material characterized by an effective orientation axis and a normalized difference between a refractive index for light polarized along TD and a refractive index for light polarized along ND being less than 0.06. The optical film has a width of greater than 0.3 m and a length a length greater than 10 m, and the effective orientation axis is aligned along the length of the optical film (MD).

Abstract: Exemplary methods include includes providing a film comprising at least one polymeric material; widening the film under a first set of processing conditions in a first draw step along the crossweb direction such that in-plane birefringence, if any, created in the film is low; and drawing the film in a second draw step along a downweb direction, while allowing the film to relax along the crossweb direction, under a second set of processing conditions, wherein the second set of processing conditions creates in-plane birefringence in at least one polymeric material.