Wide band semi-specular mirror film incorporating nanovoided polymeric layer
First Claim
1. A reflective film, comprising:
- a multilayer optical film having a first major surface and a second major surface, wherein the multilayer optical film includes a plurality of microlayers configured to provide a broad reflection band that shifts as a function of incidence angle, the multilayer optical film having a long wavelength band edge disposed at a wavelength no greater than 1600 nm for normally incident light; and
a diffusing layer in contact with the first major surface, the diffusing layer adapted to scatter visible light into the multilayer optical film over a range of angles such that the scattered light can be substantially reflected by the broad reflection band;
wherein the diffusing layer comprises a polymer binder having a nanovoided morphology comprising a plurality of interconnected voids or a network of voids dispersed in the polymer binder; and
wherein the reflective film has a total hemispheric reflectivity for visible light of at least 97% when the second major surface of the multilayer optical film is in contact with an absorbing material.
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Accused Products
Abstract
Low loss, high reflectivity wide band mirror films provide a desired mix of specular reflection and diffuse reflection or scattering to provide semi-specular reflectivity. The mirror films generally include both a specularly reflective multilayer optical film (MOF) having a wide reflection band, and a scattering layer. In some cases a low refractive index TIR layer is sandwiched between the MOF and the scattering layer. In other cases the scattering layer contacts the MOF directly. In embodiments that include the TIR layer, the TIR layer preferably has a nanovoided morphology and includes a plurality of particles and a polymer binder. In embodiments wherein the scattering layer contacts the MOF directly, the scattering layer preferably also has a nanovoided morphology and includes a plurality of particles and a polymer binder.
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Citations
16 Claims
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1. A reflective film, comprising:
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a multilayer optical film having a first major surface and a second major surface, wherein the multilayer optical film includes a plurality of microlayers configured to provide a broad reflection band that shifts as a function of incidence angle, the multilayer optical film having a long wavelength band edge disposed at a wavelength no greater than 1600 nm for normally incident light; and a diffusing layer in contact with the first major surface, the diffusing layer adapted to scatter visible light into the multilayer optical film over a range of angles such that the scattered light can be substantially reflected by the broad reflection band; wherein the diffusing layer comprises a polymer binder having a nanovoided morphology comprising a plurality of interconnected voids or a network of voids dispersed in the polymer binder; and wherein the reflective film has a total hemispheric reflectivity for visible light of at least 97% when the second major surface of the multilayer optical film is in contact with an absorbing material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification