US 12,276,821 B2
Optical film device
Robert M. Jennings, Shoreview, MN (US); Jo A. Etter, Stillwater, MN (US); Susan L. Kent, Shorewood, MN (US); Erin A. McDowell, Afton, MN (US); Timothy L. Wong, West St. Paul, MN (US); and Zhisheng Yun, Sammamish, WA (US)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Filed on Apr. 17, 2024, as Appl. No. 18/638,160.
Application 18/638,160 is a division of application No. 17/939,183, filed on Sep. 7, 2022, granted, now 11,988,858.
Application 17/939,183 is a division of application No. 15/733,257, granted, now 11,467,329, issued on Oct. 11, 2022, previously published as PCT/IB2019/051262, filed on Feb. 15, 2019.
Claims priority of provisional application 62/632,033, filed on Feb. 19, 2018.
Prior Publication US 2024/0264350 A1, Aug. 8, 2024
Int. Cl. G02B 5/30 (2006.01); G02B 5/10 (2006.01); G02B 27/01 (2006.01); G02B 3/00 (2006.01)
CPC G02B 5/3033 (2013.01) [G02B 5/10 (2013.01); G02B 5/3041 (2013.01); G02B 5/3066 (2013.01); G02B 27/0172 (2013.01); G02B 2003/0093 (2013.01); G02B 2027/013 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A device, comprising:
at least one optical film and having an active area that is curved along a first direction and along an orthogonal second direction, wherein:
a portion of the active area has a sag to diameter ratio, S/D, greater than 0.025;
there is at least one point, p0, on the surface of the active area such that a surface normal direction at p0 is parallel to a normal vector of a reference plane of the active area;
each point, p, on the surface of the active area has a linear polarization block axis orientation angle between a measured block axis tangent direction at p and a local reference tangent direction at p, the local reference tangent direction being coplanar with the normal vector of the reference plane and the measured block axis tangent direction at p0; and
a maximum variation of linear polarization block axis angles for all points of the portion of the active area, βmax−βmin, is less than 22(S/D) degrees.