US 12,147,066 B2
Optical stack including multilayer optical film and radio-wave anti-reflection sheet
Fan Long, Panyu District (CN); Bharat R. Acharya, Woodbury, MN (US); Jaewon Kim, Woodbury, MN (US); Jingfei Chen, Shanghai (CN); Huijie Xie, Beijing (CN); and Zhe Hu, Suzhou (CN)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Appl. No. 18/567,823
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed Jun. 28, 2021, PCT No. PCT/CN2021/102717
§ 371(c)(1), (2) Date Dec. 7, 2023,
PCT Pub. No. WO2023/272428, PCT Pub. Date Jan. 5, 2023.
Prior Publication US 2024/0264347 A1, Aug. 8, 2024
Int. Cl. G02B 5/26 (2006.01); G01S 7/03 (2006.01); G01S 13/931 (2020.01); G02B 1/04 (2006.01); G02B 5/20 (2006.01); G02B 5/30 (2006.01); H01Q 1/42 (2006.01)
CPC G02B 5/26 (2013.01) [G01S 7/03 (2013.01); G01S 13/931 (2013.01); G02B 1/04 (2013.01); G02B 5/208 (2013.01); G02B 5/3008 (2013.01); H01Q 1/422 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical stack comprising:
a substrate;
a radio-wave anti-reflection sheet configured to reduce reflection from the optical stack of radio waves emitted from a transmitter at a predetermined operating frequency; and
a multilayer optical film disposed between the radio-wave anti-reflection sheet and the substrate, such that for light substantially normally incident on the multilayer optical film and for at least one polarization state:
an average optical reflectance of the multilayer optical film is greater than about 70% in a first wavelength range of about 420 nm to about 680 nm; and
an average optical transmittance of the multilayer optical film is greater than about 70% in a second wavelength range at least about 100 nm wide and disposed between about 800 nm and about 1600 nm,
wherein for radiation substantially normally incident on the radio-wave anti-reflection sheet such that at least a portion of the radiation is transmitted through each of the radio-wave anti-reflection sheet, the multilayer optical film, and the substrate; and for a first frequency range at least 20 GHz wide, centered on the predetermined operating frequency, and disposed between about 1 GHz and about 120 GHz:
a return loss of the optical stack is asymmetric about the predetermined operating frequency in the first frequency range; and
the optical stack has a largest return loss S11L in the first frequency range of less than −10 dB and a difference between the largest return loss S11L and a smallest return loss S11S in the first frequency range is less than about 2 dB.