Phase difference film, optical film, and display device

A phase difference film formed by using a composition including a polymerizable liquid crystal compound having a mesogen group,

• wherein, in the phase difference film, in a case where an order parameter of the mesogen group in an in-plane slow axis direction of the phase difference film is set as Sx, an order parameter of the mesogen group in a direction orthogonal to the in-plane slow axis direction in a plane is set as Sy, and an order parameter of the mesogen group in a thickness direction of the phase difference film is set as Sz,
• in a case where the mesogen group has a rod shape, requirements of Expressions (1) to (3) are satisfied, and
• in a case where the mesogen group has a disc shape, requirements of Expressions (4) to (6) are satisfied,
• Sx>Sz>Sy Expression (1)
• −0.300<Sz<0.200 Expression (2)
• Sx>0.050 Expression (3)
• Sy>Sz>Sx Expression (4)
• −0.200<Sz<0.300 Expression (5)
• Sy>0.050 Expression (6)
• here, in a case where the mesogen group has a rod shape, the order parameter is calculated by using a long axis of the mesogen group as a reference, and in a case where the mesogen group has a disc shape, the order parameter is calculated by using an axis orthogonal to a disc surface of the mesogen group, as a reference, and
• in a case where the in-plane slow axis direction of the phase difference film is set as an x axis, a direction orthogonal to the in-plane slow axis direction is set as a y axis, and the thickness direction of the phase difference film is set as a z axis, and angles between an average alignment direction M of the mesogen groups, and the x axis, the y axis, and the z axis are θX, θY, and θZ, the order parameter Sx, the order parameter Sy, and the order parameter Sz are respectively represented by the following expressions:
• Sx
• =
• 3
• ⁢
• 〈
• cos
• 2
• ⁢
• θ
• ⁢
• ⁢
• x
• 〉
• -
• 1
• 2
• Sy
• =
• 3
• ⁢
• 〈
• cos
• 2
• ⁢
• θ
• ⁢
• ⁢
• y
• 〉
• -
• 1
• 2
• Sz
• =
• 3
• ⁢
• 〈
• cos
• 2
• ⁢
• θ
• ⁢
• ⁢
• z
• 〉
• -
• 1
• 2
• .