Reflective film combinations with output confinement in both polar and azimuthal directions and related constructions

摘要

A reflective film includes microlayers arranged into optical repeat units to reflect light in an extended wavelength band, with thinner and thicker ones of the optical repeat units being disposed generally towards a thin side and thick side, respectively, of the film. The microlayers are tailored to provide the film with a reflectivity, for p-polarized light incident in a first plane, that decreases by at least half from an initial value at normal incidence to a value R1 at an incidence angle θoblique. The film has a reflectivity for p-polarized light incident in a second plane of R2 at the angle θoblique, where R2>R1. A polarizer is combined with the reflective film, the combination defining an oblique transmission lobe, and the thick and thin sides of the reflective film are oriented relative to the polarizer to reduce an azimuthal width Δφ of the transmission lobe.

主权项

1. A combination, comprising:
a multilayer optical film having a plurality of microlayers arranged into optical repeat units for reflecting light over an extended wavelength band, adjacent microlayers having refractive index differences that define a first and second in-plane axis, such that the film has a reflectivity of at least 75% for all polarization states of normally incident light, the refractive index differences also being such that for p-polarized light incident on the film in a first plane of incidence that includes the first axis, the film has a reflectivity that decreases by at least half from an initial value at normal incidence to a value R1 at an incidence angle θoblique measured from a normal of the surface of the multilayer optical film, but for p-polarized light incident on the film in a second plane that includes the second axis, the film has a reflectivity R2>R1 at the incidence angle θoblique; and a polarizer having a pass axis and a block axis, the polarizer and the multilayer optical film being disposed to define an oblique transmission lobe; wherein the optical repeat units have an optical thickness distribution across a thickness of the multilayer optical film, the thickness distribution defining a thin side and a thick side of the multilayer optical film, thinner ones of the optical repeat units being disposed generally towards the thin side and thicker ones of the optical repeat units being disposed generally towards the thick side; and wherein the thin and thick sides of the multilayer optical films are oriented relative to the polarizer to reduce an azimuthal collimation Δφe of the transmission lobe, wherein the azimuthal collimation Δφe is measured in a plane parallel to the surface of the multilayer optical film.