US 11,988,856 B2
Display medium, authenticity determination method, and article including display medium
Yasuhide Fujino, Tokyo (JP)
Assigned to ZEON CORPORATION, Tokyo (JP)
Appl. No. 17/596,908
Filed by ZEON CORPORATION, Tokyo (JP)
PCT Filed Jun. 4, 2020, PCT No. PCT/JP2020/022170
§ 371(c)(1), (2) Date Dec. 21, 2021,
PCT Pub. No. WO2020/261923, PCT Pub. Date Dec. 30, 2020.
Claims priority of application No. 2019-119065 (JP), filed on Jun. 26, 2019.
Prior Publication US 2022/0326422 A1, Oct. 13, 2022
Int. Cl. G02B 5/30 (2006.01); B42D 25/364 (2014.01)
CPC G02B 5/3016 (2013.01) [B42D 25/364 (2014.10)] 5 Claims
OG exemplary drawing
 
1. A display medium comprising a first layer, a second layer, and a third layer, wherein:
a part or an entirety of the first layer, a part or an entirety of the second layer, and a part or an entirety of the third layer are stacked in a thickness direction in this order;
the first layer is a layer that is capable of reflecting circularly polarized light having a rotation direction D1 and allowing to pass therethrough circularly polarized light having a rotation direction D2, which is a direction opposite to the rotation direction D1;
the second layer is a phase difference layer;
the third layer is a layer that is capable of reflecting circularly polarized light whose rotation direction is the rotation direction D1 and allowing to pass therethrough circularly polarized light whose rotation direction is the rotation direction D2;
the first layer is a layer having cholesteric regularity, and the third layer is a layer containing resin flakes that have cholesteric regularity; and
a value of Re(400)/Re(560) is 1.00 or more, a value of Re(650)/Re(560) is 1.000 or less, and Re(560) is 300 nm or more and 1250 nm or less, wherein Re(400) represents an in-plane retardation Re of the second layer at wavelength 400 nm, Re(560) represents an in-plane retardation Re of the second layer at wavelength 560 nm, and Re(650) represents an in-plane retardation Re of the second layer at wavelength 650 nm.