Optical film
Assignee3M Innovative Properties Company
InventorsJames M. Jonza, Michael F. Weber, Andrew J. Ouderkirk, Carl A. Stover
Life of this patent
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Abstract
Birefringent optical films have a Brewster angle (the angle at which reflectance of p-polarized light goes to zero) which is very large or is nonexistent. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p-polarized light decreases slowly with angle of incidence, are independent of angle of incidence, or increase with angle of incidence away from the normal. As a result, multilayer films having high reflectivity (for both planes of polarization for any incident direction in the case of mirrors, and for the selected direction in the case of polarizers) over a wide bandwidth, can be achieved.
Claims31
A multilayered optical film, comprising:
- a plurality of alternating first and second optical layers;
- wherein the first optical layers comprise a first polymer selected from polyalkylene terephthalates, polyalkylene naphthalates, and copolymers of polyalkylene naphthalates and the first polymer has at least 0.05 difference in in-plane refractive indices;
- and
- wherein the second optical layers comprise a second polymer selected from copolyesters and copolycarbonates and the second polymer has isotropic in-plane refractive indices.
A polarizer, comprising:
- a plurality of alternating first and second optical layers;
- wherein the first optical layers comprise a first polymer selected from polyalkylene naphthalates and copolymers of polyalkylene naphthalates and the first polymer has at least 0.05 difference in in-plane refractive indices;
- and
- wherein the second optical layers comprise a second polymer selected from copolyesters and copolycarbonates and the second polymer has isotropic in-plane refractive indices.
A polarizer, comprising:
- a plurality of alternating first and second optical layers;
- wherein the first optical layers comprise a first polymer selected from copolymers of polyethylene naphthalate and the first polymer has at least 0.05 difference in in-plane refractive indices;
- and
- wherein the second optical layers comprise a second polymer selected from copolymers of polyethylene naphthalate.
Dependencies are inferred from the claim text.