Display laminate with single packet biaxially birefringent reflective polarizer
First Claim
1. A laminate, comprising:
- a reflective polarizer having only one packet of microlayers that reflects and transmits light by optical interference, the microlayers configured to define a first pass axis, a first block axis, and a first thickness axis perpendicular to the first pass axis and the first block axis; and
an absorbing polarizer having a second pass axis and a second block axis, the absorbing polarizer attached to the reflective polarizer with no air gap therebetween and such that the first and second pass axes are substantially aligned;
wherein the packet of microlayers includes alternating first and second microlayers, the first microlayers being biaxially birefringent;
wherein the reflective polarizer in isolation is characterized by a spectral transmission, for p-polarized light incident at a polar angle of 60 degrees in a reference plane that includes the first pass axis and the first thickness axis, in which(a) the spectral transmission has a value in a range from 70% to 90% for at least some wavelengths from 450 to 700 nm; and
(b) a high frequency spectral variability Δ
, over a wavelength range from 400 to 700 nm, is less than 0.08.
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Accused Products
Abstract
Multilayer optical film reflective polarizers previously considered to have excessive off-axis color can provide adequate performance in an LC display without any high haze light diffusing layer or air gap between the reflective polarizer and the back absorbing polarizer of the display. The reflective polarizer has only one packet of microlayers, and is oriented using a standard tenter such that birefringent microlayers in the film are biaxially birefringent. The microlayers in the packet have a layer thickness profile suitably tailored to avoid excessive perceived color at normal and oblique angles. A laminate made by combining this type of reflective polarizer with an absorbing polarizer, without an air gap or any high haze light diffusing layer or structure between the polarizers, can be used and incorporated into a liquid crystal display or the like with adequate color performance both at normal incidence and oblique incidence up to a polar angle of 60 degrees.
21 Citations
16 Claims
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1. A laminate, comprising:
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a reflective polarizer having only one packet of microlayers that reflects and transmits light by optical interference, the microlayers configured to define a first pass axis, a first block axis, and a first thickness axis perpendicular to the first pass axis and the first block axis; and an absorbing polarizer having a second pass axis and a second block axis, the absorbing polarizer attached to the reflective polarizer with no air gap therebetween and such that the first and second pass axes are substantially aligned; wherein the packet of microlayers includes alternating first and second microlayers, the first microlayers being biaxially birefringent; wherein the reflective polarizer in isolation is characterized by a spectral transmission, for p-polarized light incident at a polar angle of 60 degrees in a reference plane that includes the first pass axis and the first thickness axis, in which (a) the spectral transmission has a value in a range from 70% to 90% for at least some wavelengths from 450 to 700 nm; and (b) a high frequency spectral variability Δ
, over a wavelength range from 400 to 700 nm, is less than 0.08. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification