Optical polarizer
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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.
105 Citations
20 Claims
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1-6. -6. (canceled)
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7. A display, comprising:
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a liquid crystal display module;
a backlight;
a front display polarizer comprising a broadband reflective polarizer having anisotropic refractive indices such that light having a first polarization state is reflected and light having a second polarization state is transmitted, the reflective polarizer having a viewing side facing away from the liquid crystal display module and an opposing side facing the liquid crystal display module.
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20. A method of increasing brightness of a display comprising a liquid crystal display module and a backlight, the method comprising the step of:
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disposing a broadband reflective polarizer with a viewing side of the reflective polarizer facing away from the liquid crystal display module and an opposing side of the reflective polarizer facing the liquid crystal display module;
wherein the reflective polarizer has anisotropic refractive indices such that light having a first polarization state is reflected and light having a second polarization state is transmitted and wherein the reflective polarizer returns at least a portion of light of the first polarization supplied by the backlight and passed by the liquid crystal module back into the backlight.
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Specification