| CPC G02B 5/3016 (2013.01) [G02B 1/08 (2013.01); G02F 2202/043 (2013.01)] | 20 Claims |
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1. A light absorption anisotropic film formed of a composition containing a liquid crystal compound and a dichroic substance,
wherein the light absorption anisotropic film has two main surfaces facing each other,
an angle between a normal direction of a main surface of the light absorption anisotropic film and a transmittance central axis of the light absorption anisotropic film is 0° to 45°,
in a case where the angle is 0°, the following requirement A1 is satisfied, and
in a case where the angle is other than 0°, the following requirement B1 is satisfied,
the requirement A1: an average polarization degree A of a polarization degree which is measured by allowing light having a wavelength of 450 nm to be incident from a direction tilted by 50° with respect to the normal direction, a polarization degree which is measured by allowing light having a wavelength of 550 nm to be incident from the direction tilted by 50° with respect to the normal direction, and a polarization degree which is measured by allowing light having a wavelength of 650 nm to be incident from the direction tilted by 50° with respect to the normal direction is 0.80 or more, and
a retardation at a wavelength of 650 nm in the direction tilted by 50° with respect to the normal direction is less than 250 nm,
the requirement B1: an average polarization degree B of a polarization degree which is measured by allowing light having a wavelength of 450 nm to be incident from a direction tilted by 50° on a normal direction side with respect to the transmittance central axis, a polarization degree which is measured by allowing light having a wavelength of 550 nm to be incident from the direction tilted by 50° on the normal direction side with respect to the transmittance central axis, and a polarization degree which is measured by allowing light having a wavelength of 650 nm to be incident from the direction tilted by 50° on the normal direction side with respect to the transmittance central axis is 0.80 or more, and
a retardation at a wavelength of 650 nm in the direction tilted by 50° on the normal direction side with respect to the transmittance central axis is less than 250 nm,
the polarization degree is a value represented by the following expression,
 in the expression, Ty0 is a transmittance with respect to polarized light in a direction orthogonal to a direction obtained by orthographically projecting the transmittance central axis onto a plane orthogonal to a direction in which the light is incident, and Tz0 is a transmittance with respect to polarized light in a direction parallel to the direction obtained by orthographically projecting the transmittance central axis onto the plane orthogonal to the direction in which the light is incident.
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