Abstract: Optical constructions use a low index of refraction layer disposed between a low absorption layer and a high absorption layer to increase confinement of light to the low absorption region of the optical constructions. Low index layers can be used in optical constructions that have multi-tiered light confinement. In these constructions, a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide. A second tier of reflection occurs at the surface of a light redirecting film having appropriately oriented refractive structures.

Abstract: Antireflective films are described comprising a light transmissive substrate and a low refractive index layer disposed on the light transmissive substrate. The low refractive index layer comprises the reaction product of polymerizable resin composition comprising at least 20 wt-% fumed silica. In one embodiment, the polymerizable resin is ethylenically unsaturated. In a favored embodiment, the low refractive index layer increases in porosity from the light transmissive substrate interface to an opposing porous surface.

Abstract: Laser-personalizable security articles include a multi-layer security document and an optically transparent processing tape. The multi-layer security document includes an optically transparent cover layer, a composite image and an imagable layer adjacent to the cover layer. The first surface of the cover layer is at least partially a microstructured surface, where the microstructured surface forms microlenses or a lenticular surface. The composite image is made by a collection of complete or partial images viewed through the microstructured surface of the cover layer. The composite image is located on or within the second surface of the cover layer. The imagable layer is a laser. The optically transparent processing tape sufficiently wets out on the misconstructured surface to render the microstructured surface invisible to a writing laser.

Abstract: Retroreflecting optical constructions are disclosed. A disclosed retroreflecting optical construction includes a retroreflecting layer that has a retroreflecting structured major surface, and an optical film that is disposed on the retroreflecting structured major surface of the retroreflecting layer. The optical film has an optical haze that is not less than about 30%. Substantial portions of each two neighboring major surfaces in the retroreflecting optical construction are in physical contact with each other.

Abstract: A gradient optical film and an optical construction including the gradient optical film are described. The gradient optical film includes a binder, a plurality of particles, and a plurality of interconnected voids having a local volume fraction. The local volume fraction of the plurality of interconnected voids varies along a thickness direction of the gradient optical film. The refractive index of the gradient optical film can also varies along a thickness direction of the gradient optical film, as the refractive index can also depend upon the local volume fraction of the plurality of interconnected voids.

Abstract: Optical constructions are disclosed. A disclosed optical construction includes a reflective polarizer layer, and an optical film that is disposed on the reflective polarizer layer. The optical film has an optical haze that is not less than about 50%. Substantial portions of each two neighboring major surfaces in the optical construction are in physical contact with each other. The optical construction has an axial luminance gain that is not less than about 1.2.

Abstract: An electronically switchable privacy device suitable for use in display devices is described. The electronically switchable privacy device comprises a first transparent electrode layer, an electronically switchable layer disposed adjacent to the first transparent electrode layer, and a second transparent electrode layer disposed adjacent to the electronically switchable layer and opposite the first transparent electrode layer. The second transparent electrode layer comprises a transparent substrate layer having a plurality of microstructured ribs extending across a major surface of the transparent substrate layer such that the microstructured ribs form an alternating series of ribs and channels, each channel having channel walls defined by adjacent ribs.

Abstract: Optical constructions use a low index of refraction layer disposed between a low absorption layer and a high absorption layer to increase confinement of light to the low absorption region of the optical constructions. Low index layers can be used in optical constructions that have multi-tiered light confinement. In these constructions, a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide. A second tier of reflection occurs at the surface of a light redirecting film having appropriately oriented refractive structures.

Abstract: This application describes a front-lit reflective display assembly including a reflective display and an illumination article for front-lighting the display when the article is optically coupled to a light source. The illumination article includes a variable index light extraction layer optically coupled to a lightguide. The variable index light extraction layer has first and second regions, the first region comprising nanovoided polymeric material, the second region comprising the nanovoided polymeric material and an additional material, the first and second regions being disposed such that for light being transported at a supercritical angle in the lightguide, the variable index light extraction layer selectively extracts the light in a predetermined way based on the geometric arrangement of the first and second regions. Front-lit reflective display devices including the front-lit reflective display assembly optically coupled to a light source are also described.

Abstract: Optical constructions use a low index of refraction layer disposed between a low absorption layer and a high absorption layer to increase confinement of light to the low absorption region of the optical constructions. Low index layers can be used in optical constructions that have multi-tiered light confinement. In these constructions, a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide. A second tier of reflection occurs at the surface of a light redirecting film having appropriately oriented refractive structures.

Abstract: Light sources are disclosed. A disclosed light source includes an optically reflective cavity that includes an input port for receiving light and an output port for transmitting light, a lamp that is disposed at the input port, and an optical stack that is disposed at the output port. The optical stack includes a forward scattering optical diffuser that is disposed at the output port and has an optical haze that is not less than about 20%, and an optical film that is disposed on the optical diffuser. The optical film enhance total internal reflection at the interface between the optical film and the optical diffuser. The optical film has an index of refraction that is not greater than about 1.3 and an optical haze that is not greater than about 5%. The optical stack also includes a reflective polarizer layer that is disposed on the optical film. Substantial portions of each two neighboring major surfaces in the optical stack are in physical contact with each other.

Abstract: A voided diffuser and an optical construction incorporating the voided diffuser are provided. The voided diffuser includes a plurality of beads and a binder composition in contact with the plurality of beads. The binder composition includes a binder and a plurality of interconnected voids. The optical construction includes the voided diffuser disposed on a substrate.

Abstract: Optical constructions are disclosed. A disclosed optical construction includes first and second optical layers having first and second major surfaces that face each other and are separated by an air gap. The first and second surfaces are susceptible to physically contacting each other at a location in the air gap. The optical construction further includes an optical film that is disposed at the location to prevent the first and second major surfaces from contacting each other at the location. The optical film has an effective index of refraction that is not greater than about 1.3.

Abstract: Retroreflecting optical constructions are disclosed. A disclosed retroreflecting optical construction includes a retroreflecting layer that has a retroreflecting structured major surface, and an optical film that is disposed on the retroreflecting structured major surface of the retroreflecting layer. The optical film has an optical haze that is not less than about 30%. Substantial portions of each two neighboring major surfaces in the retroreflecting optical construction are in physical contact with each other.

Abstract: Optical constructions use a low index of refraction layer (120) disposed between a low absorption layer (101) and a high absorption layer (103) to increase confinement of light to the low absorption region of the optical constructions. Low index layers can be used in optical constructions that have multi-tiered light confinement. In these constructions, a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide (110). A second tier of reflection occurs at the surface of a light redirecting film having appropriately oriented refractive structures.

Abstract: Light sources are disclosed. A disclosed light source includes an optically reflective cavity that includes an input port for receiving light and an output port for transmitting light, a lamp that is disposed at the input port, and an optical stack that is disposed at the output port. The optical stack includes a forward scattering optical diffuser that is disposed at the output port and has an optical haze that is not less than about 20%, and an optical film that is disposed on the optical diffuser. The optical film enhance total internal reflection at the interface between the optical film and the optical diffuser. The optical film has an index of refraction that is not greater than about 1.3 and an optical haze that is not greater than about 5%. The optical stack also includes a reflective polarizer layer that is disposed on the optical film. Substantial portions of each two neighboring major surfaces in the optical stack are in physical contact with each other.

Abstract: Microreplicated light redirecting films suitable for use in autostereoscopic displays and backlights are made to incorporate at least one nanovoided layer whose interface with another layer forms an embedded structured surface of the light redirecting film. The nanovoided layer includes a polymer binder and optional nanoparticles, and may have a refractive index less than 1.35 or 1.3. The light redirecting films may be adapted for attachment to one or more other components of an autostereoscopic display, such as a display panel and/or a light guide of a backlight.

Abstract: Presently described is a method for coupling an optical film to a substrate, laminated optical constructions comprising an optical film and an optical coupling layer disposed on a surface layer of the optical film, and coating compositions useful for optical an optical coupling layer. The coating compositions comprise at least 40 wt.-% inorganic nanoparticles having a refractive index of at least 1.85 and a polymeric silane surface treatment.

Abstract: Lightguide is disclosed. The lightguide includes a light guiding layer for propagating light by total internal reflection, and an optical film that is disposed on the light guiding layer. The optical film includes a plurality of voids, an optical haze that is not less than about 30%, and a porosity that is not less than about 20%. Substantial portions of each two neighboring major surfaces in the lightguide are in physical contact with each other.

Abstract: A process and apparatus for producing a nanovoided article, a nanovoided coating, and a low refractive index coating is described. The process includes providing a first solution of a polymerizable material in a solvent; at least partially polymerizing the polymerizable material to form a composition that includes an insoluble polymer matrix and a second solution, wherein the insoluble polymer matrix includes a plurality of nanovoids that are filled with the second solution; and removing a major portion of the solvent from the second solution. An apparatus for the process is also described, and includes a webline, a coating section, a partial polymerization section, and a solvent removal section.