Patent ID: 11927783
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 5:
6. The optical system of claim 1, wherein the reflective polarizer comprises a plurality of alternating first and second polymeric layers,
each first and second polymeric layer having an average thickness less than about 500 nm, for each pair of adjacent first and second polymeric layers:
the first layer has an index n1x along the first polarization state, an index of refraction my along the second polarization state, and an index n1z along a z-axis orthogonal to the first and second polarization states; and
the second layer has an index n2x along the first polarization state, an index of refraction n2y along the second polarization state, and an index n2z along the z-axis, such that for at least one wavelength in a predetermined wavelength range extending at least from about 450 nm to about 600 nm:
a maximum difference between n1x, my and n1z is less than about 0.002; and
a difference between n2x and n1x is greater than about 0.2.