Optical polarizer
First Claim
1. A method for manufacturing a polarizer, comprising the steps of:
- providing a reflective polarizer film including a polymeric material that becomes birefringent upon stretching;
coating polyvinyl alcohol onto the reflective polarizer film; and
stretching the coated reflective polarizer film to orient both the polymeric material of the reflective polarizer film and the polyvinyl alcohol.
1 Assignment
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Accused Products
Abstract
A reflective polarizer and a dichroic polarizer are combined to provide an improved optical polarizer. The dichroic and reflective polarizers are typically in close proximity to each other, and are preferably bonded together to eliminate the air gap between the polarizers. The combination of the two polarizers provides a high reflectivity of one polarization and high transmission for the perpendicular polarization from the reflective polarizer side of the combined polarizer, and high absorption and transmission for light of orthogonal polarization from the dichroic polarizer side. The combination also reduces iridescence as seen in transmission and when viewed in reflection from the dichroic polarizer side. The increased extinction ratio and low reflectivity of the optical polarizer allows use of a lower extinction ratio dichroic polarizer in applications requiring a given extinction ratio and high transmission.
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Citations
21 Claims
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1. A method for manufacturing a polarizer, comprising the steps of:
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providing a reflective polarizer film including a polymeric material that becomes birefringent upon stretching; coating polyvinyl alcohol onto the reflective polarizer film; and stretching the coated reflective polarizer film to orient both the polymeric material of the reflective polarizer film and the polyvinyl alcohol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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- 20. A method for manufacturing a polarizer comprising the step of simultaneously stretching a film having a first material which becomes birefringent upon stretching to form a reflective polarizer and a second material used to form a dichroic polarizer.
Specification