Abstract: An optical film having structures that vary in height along their length where the variations have a nominal period of less than forty times the nominal height of the structures is taught. In some embodiments of the invention the variation is random.

Abstract: An optical turning film has a first surface including an array of prisms. The array has a plurality of first prisms, with each of the first prisms having a first prism configuration, and a plurality of second prisms, with each of the second prisms having a second prism configuration different from the first prism configuration. The optical film also has a second surface opposing the first surface, and light rays incident to the first surface are directed by the plurality of first prism and the plurality of second prisms along a direction substantially parallel to a viewing axis.

Abstract: A lighted sign housing is provided having a sign face with both light-transmissive portions and light-blocking portions; and a reflective film applied to at least a portion of the light-blocking portions toward the interior of the sign housing. A method of using the reflective film is also provided.

Abstract: An optical film has surface that reduces the occurrence of optical defects in a display using the film. In particular, the surface has randomized characteristics that reduce such defects as wet-out, Newton's rings, and Moiré effects. The film has a first surface free of regular structure, the first surface having a plurality of local height maxima, a characteristic measure of the first surface having a random value within a predetermined range. The film also has a second surface opposing the first surface. A method of making an optical film includes embossing a pattern lacking regular structure onto a first surface of a film, wherein the first surface has a plurality of local height maxima, a characteristic measure of the first surface having a random value within a predetermined range.

Abstract: An optical film has surface that reduces the occurrence of optical defects in a display using the film. In particular, the surface has randomized characteristics that reduce such defects as wet-out, Newton's rings, and Moiré effects. The film has a first surface free of regular structure, the first surface having a plurality of local height maxima, a characteristic measure of the first surface having a random value within a predetermined range. The film also has a second surface opposing the first surface. A method of making an optical film includes embossing a pattern lacking regular structure onto a first surface of a film, wherein the first surface has a plurality of local height maxima, a characteristic measure of the first surface having a random value within a predetermined range.

Abstract: Optical devices using reflective polarizers and, in particular, diffusely reflective polarizers are provided. Many of the optical devices utilize the diffusely reflecting and specularly transmitting properties of diffusely reflecting polarizers to enhance their optical characteristics. The optical devices include a lighting system which uses a reflector formed from a diffusely reflecting polarizer attached to a specular reflector. Another optical device is a display apparatus which uses a diffusely reflecting polarizer layer in combination with a turning lens which folds shallow angle light toward a light modulating layer. Other optical devices exploit the depolarizing characteristics of a diffusely reflecting polarizer when reflecting light. Still other optical devices use diffusely reflecting polarizers to recycle light and improve display illumination.

Abstract: Optical devices according to the present invention include a multilayer optical film in which at least one of the layers comprises an oriented birefringent polymer. The multilayer optical film exhibits low absorptivity and can reflect light approaching at shallow angles as well as normal to the film.

Abstract: A brightness enhancement article that includes: (a) a transparent, flexible substrate; (b) a first major surface having an array of prisms with blunted or rounded peaks characterized by a chord width, cross-sectional pitch width, and radius of curvature in which the chord width is equal to about 20-40% of the cross-sectional pitch width and the radius of curvature is equal to about 20-50% of the cross-sectional pitch width; and (c) a second major surface characterized by a plurality of light scattering protrusions. The article has a haze value between about 20-60% and a transmission value no greater than about 94% when measured under conditions in which the first surface has a substantially planar topography.

Abstract: A transflector is described which increases efficiency and brightness under both ambient and supplemental lighting conditions in visual display applications. In one embodiment, the transflector includes a reflective polarizing element that reflects one polarization of light and transmits the other. In an alternate embodiment, the transflector includes a reflective polarizing element and a diffusing element such that the transflector diffusely reflects light of one polarization and transmits the other. The transflector is useful for both reflective and transflective liquid crystal displays.

Abstract: A transflector is described which increases efficiency and brightness under both ambient and supplemental lighting conditions in visual display applications. In one embodiment, the transflector includes a reflective polarizing element that reflects one polarization of light and transmits the other. In an alternate embodiment, the transflector includes a reflective polarizing element and a diffusing element such that the transflector diffusely reflects light of one polarization and transmits the other. The transflector is useful for both reflective and transflective liquid crystal displays.

Abstract: Optical devices such as light pipes which incorporate multilayer optical films in which the refractive indices of two adjacent layers in the thickness direction are substantially matched or are small relative to the difference in refractive indices of said two adjacent layers in an given in-plane direction which is at least 0.05. The multilayer optical film exhibits low absorptivity and can reflect light approaching at shallow angles as well as normal to the film.

Abstract: A transflector is described which increases efficiency and brightness under both ambient and supplemental lighting conditions in visual display applications. In one embodiment, the transflector includes a reflective polarizing element that reflects one polarization of light and transmits the other. In an alternate embodiment, the transflector includes a reflective polarizing element and a diffusing element such that the transflector diffusely reflects light of one polarization and transmits the other. The transflector is useful for both reflective and transflective liquid crystal displays.

Abstract: Optical devices such as light pipes which incorporate multilayer optical films in which the refractive indices of two adjacent layers in the thickness direction are substantially matched or are small relative to the difference in refractive indices of said two adjacent layers in an given in-plane direction which is at least 0.05.

Abstract: A backlight display includes a case having an optical window through which displayed information may be viewed. In addition it includes an electroluminescent panel for providing the backlight. It further includes a structured surface material between the electroluminescent panel and the optical window. The structured surface material has the property of reflecting light entering it while making an angle in a first predetermined group of angles with the axis of the display back to the electroluminescent panel. It further has the property of refracting light entering it while making an angle in a second predetermined group of angles to the axis of the display such that a majority of the light in the second group will exit in an output wedge that is smaller than the input wedge.

Abstract: A multiple layer reflective polarizer 12 is described. This element is placed between and optical cavity 24 and an LCD module 16 to form an optical display. The reflective polarizer reflects some light into the optical cavity 24 where it is randomized and may ultimately emerge with the correct polarization to be transmitted out of the display.

Abstract: Highly efficient diffusely reflecting multilayer mirrors diffusely reflect light incident upon them. Highly efficient diffusely reflecting multilayer polarizers diffusely reflect light of one polarization while diffusely transmitting the other polarization. The diffusely reflecting mirror includes a light diffusing element and a multilayer mirror element. The diffusely reflecting polarizer includes a light diffusing element and a multilayer reflective polarizing element.

Abstract: The present invention includes a structured optical film with variable pitch peaks and/or grooves to reduce the visibility of moire interference patterns and optical displays incorporating one or more layers of the film. The pitch variations can be over groups of adjacent peaks and/or valleys or between adjacent pairs of peaks and/or valleys.

Abstract: A brightness enhancement film has a plurality of linear prisms. The prisms are disposed in pairs, each pair having first and second prisms and each prism has a prism angle and a valley angle. Either the prism angles or the valley angles, but not both, are equal.

Abstract: A brightness enhanced reflective polarizer includes a reflective polarizer and a structured surface material.

Abstract: Highly efficient diffusely reflecting multilayer mirrors diffusely reflect light incident upon them. Highly efficient diffusely reflecting multilayer polarizers diffusely reflect light of one polarization while diffusely transmitting the other polarization. The diffusely reflecting mirror includes a light diffusing element and a multilayer mirror element. The diffusely reflecting polarizer includes a light diffusing element and a multilayer reflective polarizing element.