US 12,271,015 B2
Optical film and optical stack
Adam D. Haag, Woodbury, MN (US); Yi-Chen Chen, Zhubei (TW); Tze Yuan Wang, New Taipei (TW); Hiroki Matsuda, Tendo (JP); Michelle L. Toy, North St. Paul, MN (US); Ryan J. Eismin, St. Paul, MN (US); John F. VanDerlofske, III, Minneapolis, MN (US); David J. McDaniel, Lino Lakes, MN (US); and Matthew B. Johnson, Woodbury, MN (US)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Appl. No. 17/605,395
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed May 20, 2020, PCT No. PCT/IB2020/054788
§ 371(c)(1), (2) Date Oct. 21, 2021,
PCT Pub. No. WO2020/234801, PCT Pub. Date Nov. 26, 2020.
Claims priority of provisional application 62/851,991, filed on May 23, 2019.
Prior Publication US 2022/0236466 A1, Jul. 28, 2022
Int. Cl. G02B 5/30 (2006.01)
CPC G02B 5/305 (2013.01) 15 Claims
OG exemplary drawing
 
1. An optical stack comprising:
a linear absorbing polarizer; and
a reflective polarizer disposed on, and bonded to, the linear absorbing polarizer, for substantially normally incident light and for at least a first wavelength in a visible wavelength range extending from about 420 nm to about 650 nm:
the reflective polarizer has an optical reflectance of at least 60% for a first polarization state and an optical transmittance of at least 60% for an orthogonal second polarization state; and
the linear absorbing polarizer has an optical absorbance of at least 60% for the first polarization state and an optical transmittance of at least 60% for the second polarization state;
wherein, when heated at 105 deg. C. for 15 minutes, a difference in shrinkage of the reflective polarizer and the linear absorbing polarizer along the first and second polarization states is greater than about zero and 0.2%, respectively; and
wherein the reflective polarizer comprises a plurality of alternating first and second polymeric layers, such that for at least the first wavelength, the first polymeric layers have a smaller average in-plane index of refraction than the second polymeric layers, the first polymeric layers having a glass transition temperature of at least 107 deg. C.