US 12,436,326 B2
Optically anisotropic film, circularly polarizing plate, and display device
Shinichi Morishima, Kanagawa (JP); Yuki Hirai, Kanagawa (JP); and Ryoji Himeno, Kanagawa (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Sep. 21, 2022, as Appl. No. 17/949,701.
Application 17/949,701 is a continuation of application No. PCT/JP2021/013607, filed on Mar. 30, 2021.
Claims priority of application No. 2020-059960 (JP), filed on Mar. 30, 2020.
Prior Publication US 2023/0012839 A1, Jan. 19, 2023
Prior Publication US 2023/0273361 A1, Aug. 31, 2023
Int. Cl. G02B 5/20 (2006.01); G02B 5/30 (2006.01); H10K 59/80 (2023.01)
CPC G02B 5/208 (2013.01) [G02B 5/305 (2013.01); G02B 5/3091 (2013.01); H10K 59/8791 (2023.02)] 12 Claims
OG exemplary drawing
 
1. An optically anisotropic film formed of a lyotropic liquid crystalline composition containing a non-colorable rod-like compound and a non-colorable plate-like compound,
wherein, in a case where a measurement to obtain an ultraviolet-visible absorption spectrum by applying linearly polarized light from a normal direction of the optically anisotropic film is carried out by changing a direction of the linearly polarized light and assuming that a direction in which an absorbance at a maximum absorption wavelength in a wavelength range of 230 to 400 nm of the rod-like compound is the highest is defined as a first direction, and a direction in which an absorbance at a maximum absorption wavelength in a wavelength range of 230 to 400 nm of the plate-like compound is the highest is defined as a second direction, the first direction and the second direction are orthogonal to each other,
the maximum absorption wavelength in the wavelength range of 230 to 400 nm of the rod-like compound is smaller than the maximum absorption wavelength in the wavelength range of 230 to 400 nm of the plate-like compound,
NzP represented by Expression (N) of the plate-like compound is negative,
NzP=(nxP−nzP)/(nxP−nyP)  Expression (N)
nxP represents a refractive index in an in-plane slow axis direction of an optically anisotropic film P, which is formed by using a mixed solution P1 obtained by mixing 10 parts by mass of the non-colorable plate-like compound and 90 parts by mass of water, in a case where the composition does not contain a salt, or is formed by using a mixed solution P2 obtained by mixing 10 parts by mass of the non-colorable plate-like compound, 90 parts by mass of water, and an amount of the salt having the same content ratio as a content ratio of the salt to the plate-like compound in the composition, in a case where the composition contains the salt, nyP represents a refractive index in an in-plane fast axis direction of the optically anisotropic film P, and nzP represents a refractive index in a thickness direction of the optically anisotropic film P, and
wherein the NzP is −0.25 to −0.19.