Broadband switchable polarizer
First Claim
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1. A light controlling film, the film having a first surface and a second surface, comprising:
- a polymerized polymer network, the polymer network varying spatially in a direction normal to the first surface, the polymerized polymer network comprising;
crosslinked high molecular weight polymeric material; and
low molecular weight polymeric material, wherein the high molecular weight polymeric material and the low molecular weight polymer material form a material having cholesteric liquid crystal (CLC) order, the CLC order oriented with respect to the first and the second surfaces, the pitch of the CLC order varying non-linearly in a direction perpendicular to the first surface, wherein light having a first polarization and a broad bandwidth incident on the first surface is substantially reflected from the film, and wherein light having a second polarization and the broad bandwidth incident on the first surface is not substantially reflected from the film, and wherein an electric field impressed in the film controls the reflection of light having the first polarization when the electric field has a component in a direction normal to the first surface; and
wherein the crosslinked high molecular weight polymeric material is less than 20% by weight of the film.
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Abstract
A light controlling film is disclosed, comprising a polymerized polymer network varying spatially in a direction normal to the film surface, where the polymerized polymer network is a crosslinked high molecular weight polymeric material mixed with a low molecular weight nematic material exibiting cholesteric liquid crystal (CLC) order, wherein wherein an electric field impressed in the film controls the reflection of circularly polarized light.
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Citations
20 Claims
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1. A light controlling film, the film having a first surface and a second surface, comprising:
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a polymerized polymer network, the polymer network varying spatially in a direction normal to the first surface, the polymerized polymer network comprising;
crosslinked high molecular weight polymeric material; and
low molecular weight polymeric material, wherein the high molecular weight polymeric material and the low molecular weight polymer material form a material having cholesteric liquid crystal (CLC) order, the CLC order oriented with respect to the first and the second surfaces, the pitch of the CLC order varying non-linearly in a direction perpendicular to the first surface, wherein light having a first polarization and a broad bandwidth incident on the first surface is substantially reflected from the film, and wherein light having a second polarization and the broad bandwidth incident on the first surface is not substantially reflected from the film, and wherein an electric field impressed in the film controls the reflection of light having the first polarization when the electric field has a component in a direction normal to the first surface; and
wherein the crosslinked high molecular weight polymeric material is less than 20% by weight of the film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of making a light controlling film, the film having a first surface and a second surface, comprising:
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applying a mixture of high molecular weight polymeric material and low molecular weight polymeric material on a surface which produces a CLC order in the mixture; and
crosslinking the high molecular weight polymeric material so that the low molecular weight material significantly diffuses throughout the film and remains distributed in a non uniform fashion across the film from the first surface to the second surface;
wherein light having a first polarization and a broad bandwidth incident on the first surface is substantially reflected from the film, and wherein light having a second polarization and the broad bandwidth incident on the first surface is not substantially reflected from the film, wherein an electric field impressed in the film substantially decreases the reflection of light of the first polarization and broad bandwidth, and wherein the step of crosslinking takes place in a time t1, long compared to the time t2 in which the low molecular weight material can significantly diffuse. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification