US 12,287,481 B2
Optical system
John D. Le, Woodbury, MN (US); Timothy L Wong, West St. Paul, MN (US); Timothy J. Nevitt, Red Wing, MN (US); and Zhisheng Yun, Sammamish, WA (US)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Appl. No. 17/639,953
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed Sep. 9, 2020, PCT No. PCT/IB2020/058391
§ 371(c)(1), (2) Date Mar. 3, 2022,
PCT Pub. No. WO2021/048767, PCT Pub. Date Mar. 18, 2021.
Claims priority of provisional application 62/899,801, filed on Sep. 13, 2019.
Prior Publication US 2022/0326523 A1, Oct. 13, 2022
Int. Cl. G02B 5/30 (2006.01); G02B 27/01 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 5/3025 (2013.01); G02B 5/3083 (2013.01); G02B 2027/0112 (2013.01); G02B 2027/0118 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An optical system for displaying first and second images to a viewer, comprising:
different first and second displays, the first display configured to produce a polarized image;
a reflective polarizer disposed between the second display and the viewer and oriented obliquely relative to the first display, the reflective polarizer comprising substantially distinct blue, green and red reflection bands;
an absorbing polarizer disposed between the first display and the reflective polarizer; and
an optical stack disposed between the reflective polarizer and the second display and comprising:
a partial reflector disposed between the reflective polarizer and the second display; and
a retarder layer disposed between the reflective polarizer and the partial reflector, such that for substantially normally incident light and for each of a blue wavelength, a green wavelength, and a red wavelength in a predetermined wavelength range extending from about 400 nm to about 700 nm:
the reflective polarizer reflects at least 70% of the incident light having a first polarization state and transmits at least 60% of the incident light having an orthogonal second polarization state; and
the partial reflector reflects at least 70% of the incident light for each of the first and second polarization states;
wherein the retarder layer is substantially a quarter wave retarder at at least one of the blue, green and red wavelengths for at least one of the first and second polarization states; and
for each of the first and second polarization states and for each of a blue-green wavelength between the blue and green wavelengths and a green-red wavelength between the green and red wavelengths:
the reflective polarizer transmits at least 70% of the incident light; and
the partial reflector transmits at least 60% of the incident light.