Patent ID: 11880104
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Computer technology (Electrical engineering)
Classification: CPC G  A | IPC G

Claim 8:
9. A reflective polarizer comprising a plurality of alternating polymeric layers numbering at least 10 in total, each polymeric layer having an average thickness less than about 500 nm, such that:
for substantially normally incident light:
for a first polarization state, the reflective polarizer has an average optical transmittance in a first wavelength range extending from about 425 nm to about 650 nm of less than about 5%; and

for a second polarization state orthogonal to the first polarization state, the reflective polarizer has an average optical transmittance T1 in the first wavelength range of greater than about 40%; and
for light incident on the reflective polarizer at an angle of incidence of about 60 degrees:
for the first polarization state and a plane of incidence parallel to the first polarization state, the reflective polarizer has an average optical transmittance in the first wavelength range of less than about 5%; and
for the second polarization state and a plane of incidence parallel to the second polarization state, an optical transmittance of the reflective polarizer comprises a first band edge separating the first wavelength range and a second wavelength range extending at least from about 850 nm to about 1100 nm, a best linear fit to the first band edge correlating the optical transmittance to wavelength at least across a wavelength range where the optical transmittance increases from about 20% to about 80% having a slope of greater than about 3%/nm and an r-squared value of greater than about 0.9, a best second order polynomial fit to the optical transmittance in the first wavelength range having a negative second order coefficient and an r-squared value of greater than about 0.9, the reflective polarizer having an average optical transmittance T2 in the first wavelength range from about 15% to about 35% and an average optical transmittance in the second wavelength range greater than about 80%, T1−T2≥10%.