Polarizing plate

Abstract

The polarizing plate is provided with: a first light-absorbing anisotropic layer that contains a first dichroic dye, has a first light-absorbing characteristic in which the absorbance at a first wavelength is extremely high, and has a first absorption axis that exhibits the first light-absorbing characteristic in one direction; and a second light-absorbing anisotropic layer which is a second light-absorbing anisotropic layer containing a second dichroic dye, has a second light-absorbing characteristic in which the absorbance is extremely high at a second wavelength different from the first wavelength, and has a second absorption axis in which the second light-absorbing characteristic is exhibited in one direction. The first light-absorbing anisotropic layer and the second light-absorbing anisotropic layer are laminated such that a first absorption axis and a second absorption axis intersect with each other.

Description

Technical Field

[0001] The invention relates to a polarizing plate. Background Art

[0002] As an optical element that can extract the vibration direction of the electric field from the random light wave, i.e., natural light, the vibration direction of the electric field is regular light, i.e., polarized light, there is a known polarizer. For polarized light, there is a shape such as linear polarized light, circular polarized light, and elliptically polarized light according to the change of the track of the front end of the electric field vector when observed from the propagation direction. The shape of this polarized light can be changed by controlling the relative phase difference of two orthogonal components of the electric field vector in the plane perpendicular to the propagation direction of light. As an optical element that controls the phase difference of two components of the electric field vector, there is a known phase difference control element.

[0003] International Publication No. 2018 / 221598 proposes a light control device that can extract linearly polarized light in two different wavelength regions, the infrared region and the visible light region, and two linearly polarized light with different vibration directions (also called polarization directions) from natural light having two wavelength regions, the infrared region and the visible light region. The light control device of International Publication No. 2018 / 221598 comprises: a polarizer for the infrared region, having an optical property of being able to extract linearly polarized light in the infrared region from natural light; a polarizer for the visible light region, having an optical property of being able to extract linearly polarized light in the visible light region from natural light; and a phase difference control element. In the light control device of International Publication No. 2018 / 221598, each optical element of the polarizer for the infrared region, the polarizer for the visible light region, and the phase difference control element becomes an independent component. Summary of the invention

[0004] Technical issues to be solved by the invention

[0005] As in the light control device of International Publication No. 2018 / 221598, if the optical elements of multiple polarizers and phase difference control elements are independent, there will be problems that are difficult to handle.

[0006] The technology of the present invention provides a polarizing plate that can convert light of a plurality of different wavelength regions into linearly polarized light of different polarization directions with simple processing.

[0007] Means for solving technical problems

[0008] The polarizing plate of the present invention comprises: a first light absorption anisotropic layer, which is a first light absorption anisotropic layer containing a first dichroic dye and has a first light absorption characteristic in which the absorbance reaches a maximum at a first wavelength and has a first absorption axis showing the first light absorption characteristic along one direction; and

[0009] a second light absorption anisotropic layer including a second dichroic dye and having a second light absorption characteristic in which the absorbance reaches a maximum at a second wavelength different from the first wavelength, and having a second absorption axis along one direction showing the second light absorption characteristic,

[0010] The first light absorption anisotropic layer and the second light absorption anisotropic layer are stacked such that the first absorption axis intersects with the second absorption axis.

[0011] At least one of the first wavelength and the second wavelength may be within a range of 700 nm to 1500 nm.

[0012] Both the first wavelength and the second wavelength may be within a range of 700 nm to 1500 nm.

[0013] Preferably, the absolute value of the difference between a first wavelength showing a local maximum in a first absorption spectrum of the first light absorption anisotropic layer and a second wavelength showing a local maximum in a second absorption spectrum of the second light absorption anisotropic layer is larger than an average value of a half-width at half-maximum of the first absorption spectrum and a half-width at half-maximum of the second absorption spectrum.

[0014] The average of the single-body transmittance in the wavelength range of 400 nm to less than 700 nm may be 50% or more.

[0015] Preferably, the first absorption axis and the second absorption axis are orthogonal to each other, and no retardation layer for imparting a phase difference to transmitted light is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer.

[0016] Alternatively, the first absorption axis and the second absorption axis are not orthogonal, a first phase difference layer is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer, the first phase difference layer is a phase difference layer that provides a phase difference to the transmitted light, and when the first wavelength is set to λ1, the phase difference generated in the light of the first wavelength λ1 that transmits the second light absorption anisotropic layer is set to ReP2(λ1), and the phase difference generated in the light of the first wavelength λ1 that transmits the phase difference layer is set to ReR1(λ1), the following formula E1 is satisfied:

[0017] The first retardation layer is disposed so that the first slow axis, which is the slow axis of the first retardation layer, is orthogonal to the second absorption axis.

[0018] ReP2(λ1) / ReR1(λ1)=1±0.2Formula E1

[0019] Moreover, the structure may be as follows: the first absorption axis and the second absorption axis are not orthogonal, and when the first wavelength is set to λ1 and the phase difference generated in the light of the first wavelength λ1 passing through the second light absorption anisotropic layer is set to ReP2(λ1), the following formula E2-1 or E2-2 is satisfied.

[0020] ReP2(λ1) / λ1=1±0.2Formula E2-1

[0021] ReP2(λ1) / λ1=0.5±0.1 Formula E2-2

[0022] It can be as follows: it also includes a third light absorption anisotropic layer, the third light absorption anisotropic layer contains a third dichroic pigment, and has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength different from the first wavelength and the second wavelength, and has a third absorption axis that shows the first light absorption characteristic along one direction, and the third light absorption anisotropic layer is configured in a manner that the third absorption axis intersects with at least one of the first absorption axis and the second absorption axis.

[0023] The polarizing plate of the present invention may be provided with a third light absorption anisotropic layer, wherein the third light absorption anisotropic layer, the first light absorption anisotropic layer and the second light absorption anisotropic layer are stacked in order from the incident direction of light, the first absorption axis is parallel to the third absorption axis, and when the third wavelength is set to λ3 and the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer is set to ReP2(λ3), the two equations E2-1 and the following equation E3-1 are satisfied, or the two equations E2-2 and the following equation E3-2 are satisfied.

[0024] ReP2(λ3) / λ3=0.5±0.1 Formula E3-1

[0025] ReP2(λ3) / λ3=1±0.2Formula E3-2

[0026] The polarizing plate of the present invention preferably comprises a first phase difference layer and a third light absorption anisotropic layer, and the third light absorption anisotropic layer, the first light absorption anisotropic layer, the first phase difference layer and the second light absorption anisotropic layer are stacked in sequence from the incident direction of light, the first absorption axis is orthogonal to the third absorption axis, and when the third wavelength is set to λ3, the phase difference generated in the light of the third wavelength λ3 transmitted through the second light absorption anisotropic layer is set to ReP2(λ3), and the phase difference generated in the light of the third wavelength λ3 transmitted through the first phase difference layer is set to ReR1(λ3), the following formula E4 is satisfied.

[0027] ReP2(λ3) / ReR1(λ3)=1±0.2 E4

[0028] The polarizing plate of the present invention may include a first light absorption anisotropic layer, a first retardation layer, a second light absorption anisotropic layer and a third light absorption anisotropic layer, which are stacked in order from the incident direction of light, and the third light absorption anisotropic layer is arranged so that the third absorption axis intersects with the first absorption axis and the second absorption axis.

[0029] A second retardation layer for imparting a phase difference to the transmitted light is further provided between the second light absorption anisotropic layer and the third light absorption anisotropic layer.

[0030] When the phase difference generated in the light of the second wavelength λ2 passing through the third light absorption anisotropic layer is set to ReP3(λ2), and the phase difference generated in the light of the second wavelength λ2 passing through the second phase difference layer is set to ReR2(λ2), the second phase difference layer satisfies the following formula E5,

[0031] The second retardation layer is disposed so that the second slow axis, which is the slow axis of the second retardation layer, is orthogonal to the third absorption axis.

[0032] ReP3(λ2) / ReR2(λ2)=1±0.2Formula E5

[0033] The polarizer of the present invention preferably has a second phase difference layer, in which the first absorption axis and the third absorption axis intersect and are not orthogonal, and when the phase difference generated in the light of the first wavelength λ1 transmitting the third light absorption anisotropic layer is set to ReP3(λ1), and the phase difference generated in the light of the first wavelength λ1 transmitting the second phase difference layer is set to ReR2(λ1), the second phase difference layer satisfies the following formula E6.

[0034] ReP3(λ1) / ReR2(λ1)=1±0.2 E6

[0035] The first light absorption anisotropic layer may include a fourth dichroic dye in addition to the first dichroic dye, and has a fourth light absorption characteristic in which the absorbance reaches a maximum at a fourth wavelength different from the first wavelength and the second wavelength, and the first absorption axis is an absorption axis that exhibits the fourth light absorption characteristic in addition to the first light absorption characteristic.

[0036] A first light absorption anisotropic layer, a third phase difference layer, a fourth phase difference layer, and a second light absorption anisotropic layer are stacked in this order from the incident direction of light.

[0037] The third retardation layer is a retardation layer that selectively provides a phase difference that changes the polarization direction to light of one of the first wavelength and the fourth wavelength output from the first light absorption anisotropic layer.

[0038] When the first wavelength is λ1, the fourth wavelength is λ4, the phase difference generated in the light with the first wavelength λ1 transmitted through the fourth phase difference layer is ReR4(λ1), the phase difference generated in the light with the first wavelength λ1 transmitted through the second light absorption anisotropic layer is ReP2(λ1), the phase difference generated in the light with the fourth wavelength λ4 transmitted through the fourth phase difference layer is ReR4(λ4), and the phase difference generated in the light with the fourth wavelength λ4 transmitted through the second light absorption anisotropic layer is ReP2(λ4),

[0039] The fourth phase difference layer satisfies at least one of the following formulas E7-1 and E7-2, and

[0040] The fourth retardation layer is arranged so that a fourth slow axis, which is a slow axis of the fourth retardation layer, is orthogonal to the second absorption axis.

[0041] ReP2(λ1) / ReR4(λ1)=1±0.2 Formula E7-1

[0042] ReP2(λ4) / ReR4(λ4)=1±0.2 E7-2

[0043] Effects of the Invention

[0044] The polarizing plate of the present invention can be easily handled and can convert a plurality of different wavelengths of light into linearly polarized light with different polarization directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a perspective view showing the overall structure of the polarizing plate according to the first embodiment.

[0046] Figure 2 It is an explanatory diagram for explaining each layer of the polarizing plate according to the first embodiment and the polarization state when light passes through each layer.

[0047] Figure 3 It is an explanatory diagram of the first absorption spectrum and the second absorption spectrum.

[0048] Figure 4 It is a perspective view showing the overall structure of a polarizing plate according to a second embodiment.

[0049] Figure 5 It is an explanatory diagram for explaining each layer of the polarizing plate according to the second embodiment and the polarization state when light passes through each layer.

[0050] Figure 6 It is an explanatory diagram for explaining each layer of the polarizing plate according to the third embodiment and the polarization state when light passes through each layer.

[0051] Figure 7 It is a perspective view showing the overall structure of a polarizing plate according to a fourth embodiment.

[0052] Figure 8 It is an explanatory diagram for explaining each layer of the polarizing plate according to the fourth embodiment and the polarization state when light passes through each layer.

[0053] Fig. 9 This is a diagram showing an example of the wavelength dependency of the phase difference of the second light absorption anisotropic layer in the polarizing plate of the fourth embodiment.

[0054] Fig.10 It is an explanatory diagram for explaining each layer of the polarizing plate according to the fifth embodiment and the polarization state when light passes through each layer.

[0055] Fig.11 This is a diagram showing an example of the wavelength dependence of the phase difference of the second light absorption anisotropic layer and the phase difference of the first phase difference layer in the polarizing plate of the fifth embodiment.

[0056] Fig.12 It is an explanatory diagram for explaining each layer of the polarizing plate according to the sixth embodiment and the polarization state when light passes through each layer.

[0057] Fig.13 It is an explanatory diagram for explaining each layer of the polarizing plate according to the seventh embodiment and the polarization state when light passes through each layer.

[0058] Fig.14 This is a diagram showing an example of the wavelength dependence of the phase difference of the third light absorption anisotropic layer and the phase difference of the second phase difference layer in the polarizing plate of the seventh embodiment.

[0059] Fig.15 It is an explanatory diagram for explaining each layer of the polarizing plate according to the eighth embodiment and the polarization state when passing through each layer.

[0060] Fig.16 : is a schematic diagram showing a configuration example of a multispectral camera to which a polarizing plate is applied.

[0061] Fig.17 This is an explanatory diagram of a method for evaluating the discrimination property of the polarizing plates of Examples. DETAILED DESCRIPTION

[0062] Hereinafter, the polarizing plate according to the embodiment of the present invention will be described with reference to the accompanying drawings. In each of the drawings, components indicated by the same reference numerals are represented as the same components. Unless otherwise specified in the specification, each component is not limited to one and may exist in plurality.

[0063] [First embodiment]

[0064] Figure 1 It is a perspective view showing the overall structure of the polarizing plate 1 according to the first embodiment.

[0065] like Figure 1 As shown, the polarizer 1 includes a first light absorption anisotropic layer POL1 and a second light absorption anisotropic layer POL2. The polarizer 1 includes a light-transmitting support 10, and the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are formed on the support 10. When the incident light L0 including the non-polarized light of the first wavelength λ1 and the second wavelength λ2 is incident, the polarizer 1 outputs the first linear polarized light L1 and the second linear polarized light L2 having different polarization directions for each wavelength of the first wavelength λ1 and the second wavelength λ2. Here, the non-polarized light refers to natural light of a light wave in which the vibration direction of the electric field is random. In addition, polarized light is light in which the vibration direction of the electric field is regular, and the polarization direction has the same meaning as the vibration direction of the electric field. Linearly polarized light refers to polarized light in which the direction of the electric field vector is constant in a plane perpendicular to the propagation direction of the light.

[0066] exist Figure 1 In the example, in order to indicate that the polarization direction is random, the incident light L0 is schematically represented as a roughly cylindrical shape, and arrows extending radially from the center of the cylinder in eight directions are overlapped and marked on the cylinder. On the other hand, the first linear polarized light L1 and the second linear polarized light L2, which have a polarization direction in one direction, are schematically represented as flat plates, and a double arrow is overlapped and marked on each flat plate shape. The polarization directions of the first linear polarized light L1 and the second linear polarized light L2 are orthogonal, and when the polarization direction of the first linear polarized light L1 is horizontal, the polarization direction of the second linear polarized light L2 is vertical.

[0067] Figure 2 It is a schematic diagram showing each layer of the polarizing plate 1 in an exploded manner, showing two layers of a first light absorption anisotropic layer POL1 and a second light absorption anisotropic layer POL2, and omitting the support 10.

[0068] The first light absorption anisotropic layer POL1 includes a first dichroic dye and has a first light absorption characteristic in which the absorbance reaches a maximum at a first wavelength λ1. The first light absorption anisotropic layer POL1 has a first absorption axis A1 that shows the first light absorption characteristic along one direction. The second light absorption anisotropic layer POL2 includes a second dichroic dye and has a second light absorption characteristic in which the absorbance reaches a maximum at a second wavelength λ2 different from the first wavelength λ1. The second light absorption anisotropic layer POL2 has a second absorption axis A2 that shows the second light absorption characteristic along one direction. Here, the first dichroic dye and the second dichroic dye are dichroic dyes that are different from each other. The first light absorption characteristic in the first light absorption anisotropic layer POL1 comes from the first dichroic dye and its associated state, and the second light absorption characteristic in the second light absorption anisotropic layer POL2 comes from the second dichroic dye and its associated state.

[0069] The dichroic dye is a dye having an elongated molecular shape and having the property of absorbing the polarization component vibrating in the long axis direction of the molecule in the incident light and transmitting the polarization component vibrating in the direction perpendicular to the long axis direction. The orientation of the dichroic dye contained in the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 is controlled, thereby giving the first absorption axis A1 and the second absorption axis A2 respectively. When the incident light L0 of non-polarized light is made to enter the first light absorption anisotropic layer POL1, the first light absorption anisotropic layer POL1 absorbs the polarization component vibrating in the axial direction of the first absorption axis A1 in the light of the first wavelength λ1, and transmits the polarization component vibrating in the direction perpendicular to the first absorption axis A1. The case where the light absorption characteristic is shown only for the polarization component in a specific vibration direction is called light absorption anisotropy.

[0070] By having such characteristics, the first light absorption anisotropic layer POL1 can convert the incident non-polarized light of the first wavelength λ1 into the first linear polarized light L1 having a polarization direction orthogonal to the first absorption axis A1. Similarly, the second light absorption anisotropic layer POL2 absorbs the polarization component vibrating in the axial direction of the second absorption axis A2 in the light of the second wavelength λ2, and transmits the polarization component vibrating in the direction orthogonal to the second absorption axis A2. The second light absorption anisotropic layer POL2 can convert the non-polarized light of the second wavelength λ2 into the second linear polarized light L2 having a polarization direction orthogonal to the second absorption axis A2. The first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 selectively show light absorption anisotropy for one of the first wavelength λ1 and the second wavelength λ2, respectively. In addition, hereinafter, "light absorption anisotropy does not work" means that such light absorption characteristics are not shown.

[0071] exist Figure 3 , an absorption spectrum 11 of the first light absorption anisotropic layer POL1 (hereinafter referred to as the first absorption spectrum 11) and an absorption spectrum 12 of the second light absorption anisotropic layer POL2 (hereinafter referred to as the second absorption spectrum 12) are shown. Figure 3 In the figure, the horizontal axis is wavelength and the vertical axis is absorbance. The first light absorption characteristic is represented by a first absorption spectrum 11 having a peak value at which the absorbance reaches a maximum at the first wavelength λ1. The maximum value of the absorbance of the first absorption spectrum 11 is represented by α. Symbol WB1 is the maximum width of the first absorption spectrum 11. The half-width at half maximum HW1 of the first absorption spectrum 11 is the half-width of the first absorption spectrum 11 at half-peak α / 2 of the maximum value α.

[0072] On the other hand, the second light absorption characteristic is represented by a second absorption spectrum 12 having a peak value at which the absorbance reaches a maximum at the second wavelength λ2. The maximum value of the absorbance of the second absorption spectrum 12 is represented by β. The half-width at half maximum HW2 of the second absorption spectrum 12 is the half-width of the second absorption spectrum 12 at half-maximum β / 2 of the maximum value β. Symbol WB2 is the maximum width of the second absorption spectrum 12.

[0073] In this way, the first absorption spectrum 11 and the second absorption spectrum 12 have widths. Therefore, they also have widths within the wavelength range included in the first linear polarized light L1 and the second linear polarized light L2. Generally, the wavelength representing a peak in the absorption spectrum is called the absorption maximum wavelength. That is, the first wavelength λ1 is the absorption maximum wavelength in the first absorption spectrum, and the second wavelength λ2 is the absorption maximum wavelength in the second absorption spectrum. Here, the first wavelength λ1 and the second wavelength λ2 as the absorption maximum wavelengths are used to explain the effects based on the first light absorption characteristic and the second light absorption characteristic.

[0074] like Figure 3 As shown in FIG. 1 , the first absorption spectrum 11 and the second absorption spectrum 12 overlap in the lower end portion where the absorbance is relatively low, but do not overlap in the region where the absorbance is higher than the lower end portion and each shows a half value of the maximum value. Therefore, the first absorption spectrum 11 and the second absorption spectrum 12, and the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 have wavelength selectivity to different wavelengths.

[0075] In the polarizing plate 1 , the first light absorption anisotropic layer POL1 having the first light absorption characteristic and the second light absorption anisotropic layer POL2 having the second light absorption characteristic are stacked on the support 10 so that the first absorption axis A1 intersects with the second absorption axis A2 .

[0076] In particular, in the polarizing plate 1 of this example, as an example, the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are arranged in a manner that the first absorption axis A1 and the second absorption axis A2 are orthogonal. Furthermore, unlike another example described later, in the polarizing plate 1 of this example, there is no phase difference layer for generating a phase difference in the transmitted light between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2. Here, the phase difference layer refers to a phase difference control element for controlling the relative phase difference of two orthogonal components of the electric field vector in a plane perpendicular to the propagation direction of light.

[0077] Furthermore, in this specification, two axes "crossing" means that the two axes are not parallel. Furthermore, in this specification, "parallel" and "orthogonal" include the range of errors allowed in the technical field to which the present invention belongs. Specifically, it refers to the strict angle range of ±10° related to parallelism and orthogonality. Therefore, two axes "orthogonal" means that the angle formed by the two axes is within the range of 90°±10°. Two axes being parallel means that the angle formed by the two axes is within the range of 0°±10°.

[0078] Here, taking the first absorption axis A1 and the second absorption axis A2 as an example, the angle formed by the two axes is defined as follows. Figure 2 The axial direction of the first absorption axis A1 shown is used as a reference, and the clockwise direction is used as the positive direction. Then, the state in which the axial directions of the first absorption axis A1 and the second absorption axis A2 are completely aligned is used as the initial position, and the rotation angle of the second absorption axis A2 when the second absorption axis A2 is rotated relative to the first absorption axis A1 is used as the angle formed by the first absorption axis A1 and the second absorption axis A2. When the axial directions of the first absorption axis A1 and the second absorption axis A2 are completely aligned, that is, when the second absorption axis A2 is in the initial position, the angle formed by the two is 0°. Under the premise that the above-mentioned "parallel" includes the range of ±10°, "the first absorption axis A1 and the second absorption axis A2 intersect", that is, "the first absorption axis A1 and the second absorption axis A2 are not parallel", excludes the range of 0°±10°, and means that the angle formed by the first absorption axis A1 and the second absorption axis A2 is greater than 10° and less than 170°. Furthermore, “the first absorption axis A1 and the second absorption axis A2 are orthogonal” means that, under the premise that the above-mentioned “orthogonal” includes the range of ±10°, the angle formed by the first absorption axis A1 and the second absorption axis A2 is in the range of 90°±10°, that is, greater than 80° and less than 100°.

[0079] As described above, when the incident light L0 including the non-polarized light of the first wavelength λ1 and the second wavelength λ2 is incident on the polarizing plate 1, the first linear polarized light L1 of the first wavelength λ1 and the second linear polarized light L2 of the second wavelength λ2 are output. The first linear polarized light L1 has a polarization direction orthogonal to the first absorption axis A1, and the second linear polarized light L2 has a polarization direction orthogonal to the second absorption axis A2. In this way, the polarizing plate 1 can output two first linear polarized lights L1 and second linear polarized lights L2 of different polarization directions for each of the first wavelength λ1 and the second wavelength λ2. In addition, the polarizing plate 1 of this example has light absorption characteristics corresponding to the first absorption spectrum 11 and the second absorption spectrum 12, and therefore does not absorb light other than the wavelengths included in the maximum width WB1 of the first absorption spectrum 11 and the maximum width WB2 of the second absorption spectrum 12. Therefore, for example, when the incident light L0 includes light other than the wavelength within the maximum width WB1 and the maximum width WB2 , the polarizing plate 1 transmits the light in a non-polarized state.

[0080] refer to Figure 2 The table in the following describes the effect of polarizing plate 1 in more detail. Figure 2 In the embodiment, the polarizing plate 1 is arranged so that the incident light L0 is incident on the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 in sequence. Figure 2 The table shows the polarization states of the first wavelength λ1 and the second wavelength λ2 contained in the incident light L0 before entering the polarizer 1 (shown as “before entering” in the table), the polarization state after passing through the first light absorption anisotropic layer POL1 and before entering the second light absorption anisotropic layer POL2 (shown as “after passing through POL1” in the table), and the polarization state after passing through the second light absorption anisotropic layer POL2 (shown as “after passing through POL2” in the table). Figure 2 In the table, non-polarized light is represented by a double arrow with two orthogonal directions. Linear polarized light is represented by a double arrow in one direction. When the double arrows point in different directions, it indicates linear polarized light with different polarization directions. Figure 2 The symbols shown in the table in are the same as those in the tables of other figures described later.

[0081] The incident light L0 enters the polarizing plate 1 from the first light absorption anisotropic layer POL1 side. The polarization states of the light of the first wavelength λ1 and the second wavelength λ2 included in the incident light L0 are as follows: Figure 2 The "before incident" in the table shows non-polarized light.

[0082] If the first wavelength λ1 and the second wavelength λ2 are each Figure 2 The effect of the polarizing plate 1 of this example on the incident light L0 will be described as follows.

[0083] The polarizing plate 1 acts on the light of the first wavelength λ1 in the incident light as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light of the first wavelength λ1 included in the incident light L0 is absorbed along the first absorption axis A1 (at Figure 2 The polarization component in the up and down directions is absorbed. Figure 2 As shown in "After passing through POL1" in the table of FIG. 1 , the light of the first wavelength λ1 that has passed through the first light absorption anisotropic layer POL1 is directed in a direction orthogonal to the first absorption axis A1 (in Figure 2 Then, the light of the first wavelength λ1 is incident on the second light absorption anisotropic layer POL2 as the first linear polarized light L1. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ. Therefore, Figure 2As shown in “after passing through POL2 ” in the table, the first linear polarized light L1 passes through the second light absorption anisotropic layer POL2 while maintaining the polarization state after passing through the first light absorption anisotropic layer POL1 . Thus, the first linear polarized light L1 is output from the polarizing plate 1 .

[0084] On the other hand, the polarizing plate 1 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Figure 2 As shown in "After passing through POL1" in the table of FIG. 1 , the light of the second wavelength λ2 passes through the first light absorption anisotropic layer POL1 in a non-polarized state. Then, in the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 of the light of the second wavelength λ2 is absorbed. As a result, Figure 2 As shown in "After passing through POL2" in the table of FIG. 1 , the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 is directed in a direction orthogonal to the second absorption axis A2 (in Figure 2 The second linear polarized light L2 (in the table, it is the up and down direction).

[0085] By the above-described operation, the polarizing plate 1 can convert the non-polarized incident light L0 into the first linearly polarized light L1 having the first wavelength λ1 and the second linearly polarized light L2 having the second wavelength λ2 having the polarization direction orthogonal to the first linearly polarized light L1 .

[0086] Thus, the polarizer 1 comprises: a first light absorption anisotropic layer POL1 having a first light absorption characteristic in which the absorbance reaches a maximum at a first wavelength λ1; and a second light absorption anisotropic layer POL2 having a second light absorption characteristic in which the absorbance reaches a maximum at a second wavelength λ2 different from the first wavelength λ1. Then, the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are stacked in such a manner that the first absorption axis A1 and the second absorption axis A2, which are their respective absorption axes, are not parallel. The layers included in the polarizer 1 are stacked and integrated, so the handling is simple. Then, the polarizer 1 has such a small structure, and can convert the light of different wavelengths λ1 and λ2 in the incident light L0 of non-polarized light into linear polarized light of different directions, respectively.

[0087] In the above example, there is no particular limitation on the wavelength region of the first wavelength λ1 and the second wavelength λ2. The first wavelength λ1 and the second wavelength λ2 may be, for example, in the visible light region or in the infrared light region. At least one of the first wavelength λ1 and the second wavelength λ2 may be in the near infrared light region, specifically, in the range of 700 nm to 1500 nm. Furthermore, both the first wavelength λ1 and the second wavelength λ2 may be in the range of 700 nm to 1500 nm.

[0088] In the polarizing plate 1, for example, if at least one of the first wavelength λ1 and the second wavelength λ2 is within the range of 700 nm to 1500 nm, at least one wavelength of near-infrared light can be converted into linear polarized light, and wavelengths of other wavelength regions such as visible light or other near-infrared light can be converted into linear polarized light of different directions. In addition, the structure in which at least one of the first wavelength λ1 and the second wavelength λ2 is set within the range of 700 nm to 1500 nm can also be applied to each polarizing plate 2 to 8 of another embodiment described later, and the same effect can be obtained.

[0089] Furthermore, in the polarizing plate 1, for example, if both the first wavelength λ1 and the second wavelength λ2 are within the range of 700 nm or more and 1500 nm or less, the first wavelength λ1 and the second wavelength λ2 of the near-infrared light can be converted into linear polarized light in different directions. In recent years, near-infrared sensors using near-infrared light have been used in a wide range of applications such as biometric authentication, distance measurement, line of sight tracking, and foreign body detection. These near-infrared sensors are mounted on mobile devices, etc. For sensing using near-infrared light, there is a suitable wavelength depending on the detection object. For example, 760 nm is generally used in vein authentication, 810 nm is generally used in iris authentication, and 940 nm is generally used in face authentication and distance measurement. Even if it is the same near-infrared light, if multiple wavelengths used for different purposes, such as 760 nm and 940 nm light, can be distinguished, multiple near-infrared sensing can be implemented using the same device. As described above, when both the first wavelength λ1 and the second wavelength λ2 are near-infrared light, the polarizer 1 can output near-infrared light and the first wavelength λ1 and the second wavelength λ2 that are different from each other are linearly polarized light in different directions. Therefore, if such a polarizer 1 and an image sensor having a polarization recognition function that can recognize multiple linearly polarized lights of different polarization directions are used, multiple infrared sensing can be performed using a single device. In addition, the structure in which both the first wavelength λ1 and the second wavelength λ2 are set within the range of 700nm or more and 1500nm or less can also be applied to each polarizer 2 to 8 of another embodiment described later, and the same effect can be obtained.

[0090] Furthermore, in the above example, Figure 3 As shown, the first absorption spectrum 11 having the maximum absorption wavelength as the first wavelength λ1 and the second absorption spectrum 12 having the maximum absorption wavelength as the second wavelength λ2 partially overlap. As described above, even if they overlap in this way, since the absorption maximum wavelengths are different in the first absorption spectrum 11 and the second absorption spectrum 12, the polarizing plate 1 also exhibits wavelength selectivity that can output linearly polarized light of different polarization directions for each wavelength.

[0091] However, both the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 act on the light in the region where the first absorption spectrum 11 and the second absorption spectrum 12 overlap. Therefore, the more overlapping regions there are, the lower the wavelength selection performance based on the polarizer 1. In order to improve the wavelength selection performance, the fewer overlapping regions there are, the better. Specifically, it is preferable to satisfy the following condition. That is, in the first absorption spectrum 11 of the first light absorption anisotropic layer POL1 and the second absorption spectrum 12 of the second light absorption anisotropic layer POL2, the absolute value Δλ of the difference between the first wavelength λ1 showing a maximum value in the first absorption spectrum 11 and the second wavelength λ2 showing a maximum value in the second absorption spectrum 12 is preferably greater than the average value of the half-width at half maximum HW1 of the first absorption spectrum 11 and the half-width at half maximum HW2 of the second absorption spectrum 12. By satisfying this condition, better wavelength selection performance can be obtained compared with the case where this condition is not satisfied.

[0092] Furthermore, in the polarizer 1, the average of the single transmittance in the wavelength range of 400nm or more and less than 700nm as the visible light region can exceed 50%. The average of the single transmittance in the visible light region in the polarizer 1 exceeding 50% means that it does not have polarization characteristics for light in the visible light region. At this time, the polarizer 1 can transmit while maintaining the polarization state of the incident light in the visible light region. In addition, the structure in which the average of the single transmittance in the wavelength range of 400nm or more and less than 700nm is 50% can also be applied to each polarizer 2 to 8 of another embodiment described later, and the same effect can be obtained. Here, the single transmittance is calculated by the following formula based on the transmitted light intensity Lt1 when the transmission axis direction of the polarizer is consistent with the vibration direction of the incident light when the linear polarized light Li is incident, and the transmitted light intensity Lt2 when the absorption axis direction of the polarizer is consistent with the vibration direction of the incident light.

[0093] Single body transmittance = (Lt1 + Lt2) / 2Li

[0094] In the polarizer 1 of this example, the first absorption axis A1 is orthogonal to the second absorption axis A2. Then, there is no phase difference layer between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 that causes a phase difference in the transmitted light. The polarizer 1 can convert the first wavelength λ1 and the second wavelength λ2 into mutually orthogonal linear polarized light. In addition, the polarizer 1 is different from the polarizer 2 described later, and there is no need to have a phase difference layer between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2. Therefore, compared with the polarizer 2 described later that has a phase difference layer, the polarizer 1 can be constructed to be simpler and thinner.

[0095] As described above, in the polarizer 1, the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are stacked in such a manner that the first absorption axis A1 and the second absorption axis A2 are orthogonal. However, the polarizer of the present invention is not limited to the above manner, and the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 can be stacked as long as the first absorption axis A1 and the second absorption axis A2 are not parallel.

[0096] "Second embodiment"

[0097] Figure 4 It is a perspective view showing the overall structure of the polarizing plate 2 according to the second embodiment. Figure 5 This is a schematic diagram of the polarizing plate 2 in which the polarizing plate 2 is decomposed and shown for each layer, and the support 10 is omitted. In the following embodiments, the differences from the polarizing plate 1 of the first embodiment are mainly described. Figure 4 The polarizer 2 shown is Figure 1 Similarly, the polarizing plate 1 shown in the figure outputs the first linear polarized light L1 and the second linear polarized light L2 having different polarization directions when the incident light L0 of non-polarized light is incident. The functional difference between the polarizing plate 2 and the polarizing plate 1 lies in the polarization direction of the second linear polarized light L2 and in that the second linear polarized light L2 is not orthogonal to the first linear polarized light L1.

[0098] The polarizer 2 of the second embodiment is similar to the polarizer 1, and the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are stacked on the support 10 in a manner that the first absorption axis A1 and the second absorption axis A2 intersect. However, in the polarizer 2, the first absorption axis A1 and the second absorption axis A2 are not orthogonal. That is, the angle formed by the first absorption axis A1 and the second absorption axis A2 is in the range of more than 10° and less than 80°, or more than 100° and less than 170°. The polarizer 2 includes a first phase difference layer R1 that gives a phase difference to the transmitted light between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2. In this way, the polarizer 2 is different from the polarizer 1 in that the angle formed by the first absorption axis A1 and the second absorption axis A2 is not orthogonal and that the first phase difference layer R1 is included.

[0099] The first phase difference layer R1 is a phase difference layer that satisfies formula E1 when the phase difference generated in the light of the first wavelength λ1 through the second light absorption anisotropic layer POL2 is set to ReP2(λ1), and the phase difference generated in the light of the first wavelength λ1 through the first phase difference layer R1 is set to ReR1(λ1).

[0100] ReP2(λ1) / ReR1(λ1)=1±0.2Formula E1

[0101] In addition, when simply referred to as phase difference in this specification, it means the in-plane phase difference.

[0102] In the polarizing plate 2 , the first retardation layer R1 is disposed so that the first slow axis S1 , which is the slow axis of the first retardation layer R1 , and the second absorption axis A2 are orthogonal to each other.

[0103] Formula E1 means that the phase difference ReP2(λ1) generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the phase difference ReR1(λ1) generated in the light of the first wavelength λ1 transmitted through the first phase difference layer R1. By arranging the first slow axis S1 of the first phase difference layer R1 and the second absorption axis A2 of the second light absorption anisotropic layer POL2 to be orthogonal, the phase difference given to the first wavelength λ1 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the first phase difference layer R1.

[0104] like Figure 4 and Figure 5 As shown, when the incident light L0 including the non-polarized light of the first wavelength λ1 and the second wavelength λ2 is incident on the polarizer 2, the light of the first wavelength λ1 is output as the first linear polarized light L1 whose polarization direction is orthogonal to the first absorption axis A1, and the light of the second wavelength λ2 is output as the second linear polarized light L2 whose polarization direction is orthogonal to the second absorption axis A2. The polarizer 2 is the same as the polarizer 1 in that the first linear polarized light L1 and the second linear polarized light L2 are output, but is different in that the polarization direction of the second linear polarized light L2 is not orthogonal to the first linear polarized light L1. The first linear polarized light L1 is a linear polarized light in a direction orthogonal to the first absorption axis A1, and the light of the second wavelength λ2 is a linear polarized light in a direction orthogonal to the second absorption axis A2. In the polarizer 2, as an example, the angle formed by the first absorption axis A1 and the second absorption axis A2 is 45°. At this time, the angle formed by the polarization directions of the first linear polarized light L1 and the second linear polarized light L2 is 45°. In addition, light included in the incident light L0 and other than the wavelengths absorbed by the first absorption characteristic and the second absorption characteristic of the polarizer 2 is transmitted through the polarizer 2 in a non-polarized state.

[0105] References Figure 2 The same table in Figure 5 The table in will explain the effect of polarizing plate 2 in more detail. Figure 5 ] represents the polarization states of the light of the first wavelength λ1 and the second wavelength λ2 included in the incident light L0 before incidence and after transmission through each layer.

[0106] The incident light L0 enters the polarizing plate 2 from the first light absorption anisotropic layer POL1 side. The polarization states of the light of the first wavelength λ1 and the second wavelength λ2 included in the incident light L0 are as follows: Figure 5 The "before incident" in the table shows non-polarized light.

[0107] If the first wavelength λ1 and the second wavelength λ2 are each Figure 5 The effect of the polarizing plate 2 of this example on the incident light L0 is described as follows.

[0108] The polarizing plate 2 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the polarization component along the first absorption axis A1 of the light of the first wavelength λ1 included in the incident light L0 is absorbed. Figure 5 As shown in "After passing through POL1" in the table of FIG. 1 , the light of the first wavelength λ1 that has passed through the first light absorption anisotropic layer POL1 becomes polarized in a direction orthogonal to the first absorption axis A1 (in Figure 5 In the table, it is linearly polarized light in the left and right directions.

[0109] The polarization direction of the first wavelength λ1 is neither parallel nor orthogonal to the first slow axis S1 of the first retardation layer R1. Therefore, the light of the first wavelength λ1 incident on the first retardation layer R1 as linearly polarized light is given a phase difference ReR1(λ1) by the first retardation layer R1, as shown in FIG. Figure 5 As shown in "After transmission R1" in the table, after passing through the first phase difference layer R1, it becomes elliptically polarized light. Then, the light of the first wavelength λ1 is incident on the second light absorption anisotropic layer POL2 as elliptically polarized light. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the second light absorption anisotropic layer POL2 imparts a phase difference ReP2(λ1) to the elliptically polarized light of the first wavelength λ1. As described above, the phase difference ReP2(λ1) is equivalent to the phase difference ReR1(λ1) (satisfying formula E1), and is configured in a manner that the first slow axis S1 of the first phase difference layer R1 is orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference imparted to the light of the first wavelength λ1 in the first phase difference layer R1 is offset by the second light absorption anisotropic layer POL2. Thus, as Figure 5 As shown in "After passing through POL2" in the table, the light of the first wavelength λ1 that has passed through the second light absorption anisotropic layer POL2 returns to the linear polarization light immediately after passing through the first light absorption anisotropic layer POL1. This linear polarization light is output from the polarizing plate 2 as the first linear polarization light L1.

[0110] On the other hand, the polarizing plate 2 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Figure 5As shown in "After passing through POL1" in the table of FIG. 1 , the light of the second wavelength λ2 passes through the first light absorbing anisotropic layer POL1 in a non-polarized state. The light of the second wavelength λ2 incident on the first phase difference layer R1 is non-polarized light, so Figure 5 As shown in "After transmission R1" in the table of FIG. 1 , the first phase difference layer R1 transmits the light of the second wavelength λ2 in a non-polarized state. Then, in the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 in the light of the second wavelength λ2 is absorbed. As a result, Figure 5 As shown in “after passing through POL2 ” in the table, the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 becomes the second linearly polarized light L2 which is linearly polarized light in a direction orthogonal to the second absorption axis A2 .

[0111] By the above-described operation, the polarizing plate 2 can convert the non-polarized incident light L0 into the first linearly polarized light L1 of the first wavelength λ1 and the second linearly polarized light L2 of the second wavelength λ2 having a polarization direction different from that of the first linearly polarized light L1 and neither perpendicular to nor parallel to that of the first linearly polarized light L1.

[0112] In the polarizing plate 2 of this example, the first absorption axis A1 and the second absorption axis A2 intersect but are not orthogonal. The polarizing plate 2, by having the first phase difference layer R1, can give a phase difference that cancels the phase difference generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer POL2 to the light of the first wavelength λ1 transmitted through the first phase difference layer R1. As in the polarizing plate 2, by adjusting the intersection angle between the first slow axis S1 of the first phase difference layer R1 and the second absorption axis A2 of the second light absorption anisotropic layer POL2, even when the first absorption axis A1 and the second absorption axis A2 are not orthogonal, the first linear polarized light L1 and the second linear polarized light L2 having polarization directions intersecting at any angle other than orthogonal can be output.

[0113] "Third embodiment"

[0114] Figure 6 FIG. 2 shows a polarizing plate 3 according to a third embodiment. Figure 1 The polarizing plate 1 of the first embodiment shown has a structure in which the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are stacked. On the other hand, the polarizing plate 3 is similar to the polarizing plate 2 of the second embodiment, and the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are arranged in a manner that the first absorption axis A1 and the second absorption axis A2 are not orthogonal. However, the polarizing plate 3 is different from the polarizing plate 2 and does not include the first phase difference layer R1.

[0115] When the phase difference generated in the light of the first wavelength passing through the second light absorption anisotropic layer POL2 is represented by ReP2 (λ1), the second light absorption anisotropic layer POL2 satisfies the following formula E2-1 or E2-2.

[0116] ReP2(λ1) / λ1=1±0.2Formula E2-1

[0117] ReP2(λ1) / λ1=0.5±0.1 Formula E2-2

[0118] The above formula E2-1 means that the phase difference ReP2(λ1) generated in the light of the first wavelength passing through the second light absorption anisotropic layer POL2 is substantially equal to the first wavelength λ1. When the phase difference ReP2(λ1) of the second light absorption anisotropic layer POL2 is substantially equal to the first wavelength λ1, if the light of the first wavelength λ1 enters the second light absorption anisotropic layer POL2 as linearly polarized light, the light of the first wavelength λ1 passes through the second light absorption anisotropic layer POL2 while maintaining the polarization direction at the time of the incident. Formula E2-2 means that the phase difference ReP2(λ1) is substantially equal to 1 / 2 of the first wavelength λ1. When the phase difference ReP2(λ1) is substantially equal to 1 / 2 of the first wavelength λ1, if light of the first wavelength λ1 enters the second light absorption anisotropic layer POL2 as linearly polarized light, it becomes linearly polarized light with its polarization direction rotated by 90° after passing through the second light absorption anisotropic layer POL2.

[0119] refer to Figure 6 The table in will explain the effect of polarizing plate 3 in more detail. Figure 6 The table in the above Figure 2 and Figure 5 The example in which the second light absorption anisotropic layer POL2 satisfies the formula E2-1 is shown.

[0120] The incident light L0 enters the polarizing plate 3 from the first light absorption anisotropic layer POL1 side. The polarization states of the light of the first wavelength λ1 and the second wavelength λ2 included in the incident light L0 are as follows: Figure 6 The "before incident" in the table shows non-polarized light.

[0121] If the first wavelength λ1 and the second wavelength λ2 are each Figure 6 The effect of the polarizing plate 3 shown on the incident light L0 is described as follows.

[0122] The polarizing plate 3 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the polarization component along the first absorption axis A1 of the light of the first wavelength λ1 included in the incident light L0 is absorbed. Figure 6As shown in the "After transmission POL1" of the table, the light of the first wavelength λ1 that has passed through the first light absorption anisotropic layer POL1 becomes linearly polarized light with a polarization direction orthogonal to the first absorption axis A1. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the polarization direction of the linearly polarized light of the first wavelength λ1 is neither parallel to nor orthogonal to the second absorption axis A2, and thus a phase difference ReP2(λ1) is imparted to the light of the first wavelength λ1. However, the phase difference ReP2(λ1) generated in the first wavelength λ1 that has passed through the second light absorption anisotropic layer POL2 is substantially equivalent to that of the first wavelength λ1 (satisfies formula E2-1), and therefore, as Figure 6 As shown in "After passing through POL2" in the table, the linearly polarized light of the first wavelength λ1 passes through the second light absorption anisotropic layer POL2 while maintaining its polarization direction. The linearly polarized light is output from the polarizing plate 3 as the first linearly polarized light L1.

[0123] On the other hand, the polarizing plate 3 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Figure 6 As shown in "After passing through POL1" in the table of FIG. 1 , the second wavelength λ2 passes through the first light absorption anisotropic layer POL1 in a non-polarized state. Then, in the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 in the light of the second wavelength λ2 is absorbed. As a result, Figure 6 As shown in “after passing through POL2 ” in the table, the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 becomes the second linearly polarized light L2 in a direction orthogonal to the second absorption axis A2 .

[0124] By the above-described action, the polarizer 3 can convert the non-polarized incident light L0 into light including the first linear polarized light L1 of the first wavelength λ1 and the second linear polarized light L2 of the second wavelength λ2 having a polarization direction intersecting the polarization direction of the first linear polarized light L1 at an angle other than orthogonal.

[0125] In the polarizing plate 3 of this example, the first absorption axis A1 and the second absorption axis A2 are not parallel and are not orthogonal. Then, the relationship between the phase difference ReP2(λ1) generated in the light of the first wavelength λ1 that transmits the second light absorption anisotropic layer POL2 and the first wavelength λ1 satisfies the above-mentioned formula E2-1. Therefore, for the second light absorption anisotropic layer POL2, when the first wavelength λ1 is incident as linearly polarized light, the first wavelength λ1 can be transmitted in the state of linearly polarized light. In addition, in the above example, the case where the relationship between the phase difference ReP2(λ1) and the first wavelength λ1 satisfies the formula E2-1 is taken as an example, but the same effect can be obtained when the above-mentioned formula E2-2 is satisfied. However, when the above-mentioned formula E2-2 is satisfied, in the second light absorption anisotropic layer POL2, the polarization direction of the linearly polarized light of the first wavelength λ1 is rotated by 90°.

[0126] Furthermore, the polarizer 3 can arbitrarily set the angle formed by the polarization directions of the first wavelength λ1 and the second wavelength λ2 to be not limited to 90° by adjusting the angle formed by the first absorption axis A1 and the second absorption axis A2. The polarizer 3 of the third embodiment is different from the polarizer 2 and does not need to have the first phase difference layer R1, so it can be made thinner.

[0127] The polarizers 1 to 3 described above have a structure with two light absorption anisotropic layers. The polarizer of the present invention may have three or more light absorption anisotropic layers. The following describes an embodiment in which three light absorption anisotropic layers are provided. In the following fourth to seventh embodiments, the polarizers 4 to 7 further include a third light absorption anisotropic layer POL3, which contains a third dichroic pigment and has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength λ3 different from the first wavelength λ1 and the second wavelength λ2 (reference Figure 7 , Figure 8 , Fig.10 , Fig.12 , Fig.13 ). The third light absorption anisotropic layer POL3 has a third absorption axis A3 that shows the first light absorption characteristic along one direction. The third light absorption anisotropic layer POL3 is configured in a manner that the third absorption axis A3 intersects with at least one of the first absorption axis A1 and the second absorption axis A2. The polarizing plate having the first to third light absorption anisotropic layers outputs outgoing light that includes the first wavelength, the second wavelength, and the third wavelength as linearly polarized light with mutually different polarization directions when incident light including non-polarized light of the first wavelength, the second wavelength, and the third wavelength is incident.

[0128] "Fourth Implementation Method"

[0129] Figure 7It is a perspective view showing the overall structure of the polarizing plate 4 according to the fourth embodiment. Figure 8 It is a schematic diagram of the polarizing plate 4 which is decomposed and shown for each layer, and the support 10 is omitted.

[0130] The polarizing plate 4 of the fourth embodiment further includes a third light absorption anisotropic layer POL3 containing a third dichroic dye in the polarizing plate 3 of the third embodiment. The third light absorption anisotropic layer POL3 has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength λ3 different from the first wavelength λ1 and the second wavelength λ2, and has a third absorption axis A3 along one direction showing the first light absorption characteristic. Figure 7 The polarizing plate 4 shown outputs a first linearly polarized light L1 , a second linearly polarized light L2 , and a third linearly polarized light L3 having different polarization directions when non-polarized incident light L0 is incident.

[0131] like Figure 7 As shown, in the polarizing plate 4 of this example, the third light absorption anisotropic layer POL3, the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 are stacked in this order from the light incident side. Figure 8 As shown, the third light absorption anisotropic layer POL3 is arranged with respect to the first light absorption anisotropic layer POL1 so that the first absorption axis A1 and the third absorption axis A3 are parallel. In the polarizer 4, the relationship between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 is the same as that of the polarizer 3.

[0132] In the polarizing plate 4, when the phase difference generated at the third wavelength λ3 passing through the second light absorption anisotropic layer POL2 is set to ReP2(λ3), the above-mentioned equation E2-1 and the following equation E3-1 are satisfied, or the equation E2-2 and the following equation E3-2 are satisfied.

[0133] ReP2(λ3) / λ3=0.5±0.1 Formula E3-1

[0134] ReP2(λ3) / λ3=1±0.2Formula E3-2

[0135] The above formula E3-1 means that the phase difference ReP2(λ3) generated in the light of the third wavelength λ3 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the third wavelength λ3. When the phase difference ReP2(λ3) generated in the light of the third wavelength λ3 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the third wavelength λ3, if the light of the third wavelength λ3 is incident on the second light absorption anisotropic layer POL2 as linearly polarized light, the light of the third wavelength λ3 is transmitted through the second light absorption anisotropic layer POL2 while maintaining the polarization direction at the time of incidence.

[0136] Formula E3-2 means that the phase difference ReP2(λ3) is substantially equal to 1 / 2 of the third wavelength λ3. When the phase difference ReP2(λ3) is substantially equal to 1 / 2 of the third wavelength λ3, if the light of the third wavelength λ3 is incident on the second light absorption anisotropic layer POL2 as linearly polarized light, it becomes linearly polarized light with the polarization direction rotated by 90° after passing through the second light absorption anisotropic layer POL2.

[0137] An example of the wavelength dependence of the phase difference of the second light absorption anisotropic layer POL2 in the polarizing plate 4 is shown in FIG. Fig. 9 .exist Fig. 9 In the example shown, in the second light absorption anisotropic layer POL2, the phase difference ReP2(λ1) with respect to the first wavelength λ1 is equal to 1 / 2 of the first wavelength λ1, and the phase difference ReP2(λ3) with respect to the third wavelength λ3 is equal to the third wavelength λ3. Fig. 9 In the example shown, the second light absorption anisotropic layer POL2 satisfies the formula E2-2 and the formula E3-2. Fig. 9 In the case of the wavelength dependency of the phase difference shown, the effect of the polarizing plate 4 on the incident light L0 will be described.

[0138] like Figure 7 As shown, when the incident light L0 of non-polarized light including the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 is incident on the polarizer 4 from the third light absorption anisotropic layer POL3 side, the first wavelength λ1 is output as the first linear polarized light L1, the second wavelength λ2 is output as the second linear polarized light L2 having a polarization direction different from that of the first linear polarized light L1, and the third wavelength λ3 is output as the third linear polarized light L3 having a polarization direction different from that of the first linear polarized light L1 and the second linear polarized light L2. That is, the polarizer 4 converts the incident light L0 of non-polarized light into light including the first linear polarized light L1, the second linear polarized light L2 and the third linear polarized light L3.

[0139] refer to Figure 8 The table in will explain the effect of polarizing plate 4 in more detail. Figure 8 ] represents the polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 before incidence and after transmission through each layer.

[0140] The incident light L0 enters the polarizer 4 from the third light absorption anisotropic layer POL3 side. The polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 are as follows: Fig.10 The "before incident" in the table shows non-polarized light.

[0141] If the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 are each Figure 8 The effect of the polarizing plate 4 of the present example on the incident light L0 will be described as follows.

[0142] The polarizing plate 4 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the first wavelength λ1. Therefore, Figure 8 As shown in "After passing through POL3" in the table of FIG. 1 , the light of the first wavelength λ1 passes through the third light absorption anisotropic layer POL3 in a non-polarized state. Then, the light of the first wavelength λ1 enters the first light absorption anisotropic layer POL1 in a non-polarized state. In the first light absorption anisotropic layer POL1, the polarization component along the first absorption axis A1 of the light of the first wavelength λ1 is absorbed. As a result, Figure 8 As shown in "After transmission POL1" in the table of FIG. 1 , the light of the first wavelength λ1 that has transmitted the first light absorption anisotropic layer POL1 becomes linearly polarized light in a direction orthogonal to the first absorption axis A1. Then, the light of the first wavelength λ1 enters the second light absorption anisotropic layer POL2 as linearly polarized light. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the second light absorption anisotropic layer POL2 gives a phase difference ReP2 (λ1) to the linearly polarized light of the first wavelength λ1. Here, the second light absorption anisotropic layer POL2 satisfies formula E2-2, and the phase difference ReP2(λ1) is approximately equal to 1 / 2 of λ1, so the linearly polarized light of the first wavelength λ1 has its polarization direction rotated by 90° in the second light absorption anisotropic layer POL2, and is output as the first linearly polarized light L1 whose polarization direction is rotated by 90° from the polarization direction when it is incident on the second light absorption anisotropic layer POL2.

[0143] The polarizing plate 4 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 and the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Figure 8 As shown in "After passing through POL3" and "After passing through POL1" in the table of FIG. 1 , the light of the second wavelength λ2 passes through the third light absorption anisotropic layer POL3 and the first light absorption anisotropic layer POL1 in a non-polarized state. Then, in the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 of the light of the second wavelength λ2 incident as non-polarized light is absorbed. As a result, Figure 8As shown in “after passing through POL2 ” in the table, the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 becomes the second linearly polarized light L2 in a direction orthogonal to the second absorption axis A2 .

[0144] The polarizing plate 4 acts on the light of the third wavelength λ3 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 into which the incident light L0 first enters, the polarization component along the third absorption axis A3 in the light of the third wavelength λ3 is absorbed. Figure 8 As shown in "After transmission POL3" in the table, the light of the third wavelength λ3 that has passed through the third light absorption anisotropic layer POL3 becomes linearly polarized light in a direction orthogonal to the third absorption axis A3. Then, the light of the third wavelength λ3 is incident on the first light absorption anisotropic layer POL1 as linearly polarized light. In the first light absorption anisotropic layer POL1, the light absorption anisotropy does not act on the light of the third wavelength λ3. Furthermore, the first absorption axis A1 is orthogonal to the polarization direction of the linearly polarized light of the third wavelength λ3, so the first light absorption anisotropic layer POL1 does not impart a phase difference to the linearly polarized light of the third wavelength λ3. Therefore, as Figure 8 As shown in "After transmission POL1" in the table, the linearly polarized light of the third wavelength λ3 does not change its polarization direction, but transmits the first light absorption anisotropic layer POL1 in the state of linearly polarized light. Then, the light of the third wavelength λ3 is incident on the second light absorption anisotropic layer POL2 as linearly polarized light. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the third wavelength λ3. On the other hand, the second light absorption anisotropic layer POL2 gives a phase difference ReP2(λ3) to the light of the third wavelength λ3. However, the phase difference ReP2(λ3) generated in the light of the third wavelength λ3 that transmits the second light absorption anisotropic layer POL2 is approximately equal to the third wavelength λ3 (satisfies formula E3-2), so the polarized light at the time of incidence is maintained. Therefore, as Figure 8 As shown in “After passing through POL2” in the table, the light of the third wavelength λ3 passes through the second light absorption anisotropic layer POL2 in the state of polarization direction when incident on the second light absorption anisotropic layer POL2 as linearly polarized light, and is output as the third linearly polarized light L3.

[0145] Through the above action, the polarizer 4 can convert the non-polarized incident light L0 into light including the first linear polarized light L1 with the first wavelength λ1, the second linear polarized light L2 with the second wavelength λ2 with a polarization direction different from the first linear polarized light L1, and the third linear polarized light L3 with the third wavelength λ3 with a polarization direction different from the first linear polarized light L1 and the second linear polarized light L2.

[0146] In the polarizer 4 of this example, the third absorption axis A3 is parallel to the first absorption axis A1. On the other hand, the two absorption axes A1 and A3 are not parallel to the second absorption axis A2, and are not orthogonal. In the polarizer 4, the relationship between the phase difference ReP2(λ1) generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer POL2 and the first wavelength λ1 satisfies the above-mentioned formula E2-2. Therefore, for the second light absorption anisotropic layer POL2, when the first wavelength λ1 is incident as linearly polarized light, the polarization direction of the linearly polarized light of the first wavelength λ1 is rotated 90° and output. The relationship between the phase difference ReP2(λ3) generated in the light of the third wavelength λ3 transmitted through the second light absorption anisotropic layer POL2 and the third wavelength λ3 satisfies the above-mentioned formula E3-2. Therefore, for the second light absorption anisotropic layer POL2, when the third wavelength λ3 is incident as linearly polarized light, the linearly polarized light of the third wavelength λ3 can be directly transmitted. That is, the second light absorption anisotropic layer POL2 can output the linearly polarized light of the first wavelength λ1 and the linearly polarized light of the third wavelength λ3 incident as linearly polarized lights of polarization directions orthogonal to each other.

[0147] In addition, in the above example, the relationship between the phase difference ReP2 (λ1) and the first wavelength λ1 satisfies the formula E2-2, and the relationship between the phase difference ReP2 (λ3) and the third wavelength λ3 satisfies the formula E3-2, but the same effect can be obtained when the formulas E2-1 and E3-1 are satisfied. However, when the formulas E2-1 and E3-1 are satisfied, the polarization direction of the linear polarization light of the first wavelength λ1 in the second light absorption anisotropic layer POL2 does not change, and the polarization direction of the linear polarization light of the third wavelength λ3 is rotated by 90°.

[0148] Since the polarizing plate 4 does not need to include the first retardation layer R1 or the second retardation layer R2 described later, the polarizing plate 4 can be made thinner.

[0149] "Fifth Implementation Method"

[0150] Fig.10 Schematic diagram of the polarizing plate 5 according to the fifth embodiment, showing the polarizing plate 5 in a disassembled manner for each layer. In fact, the polarizing plate 5 is formed by laminating each layer on a support 10 and integrating them similarly to the polarizing plates 1 to 4 .

[0151] The polarizing plate 5 of the fifth embodiment is similar to the polarizing plate 2 of the second embodiment, and includes the first light absorption anisotropic layer POL1, the first phase difference layer R1, and the second light absorption anisotropic layer POL2 in this order. Then, the polarizing plate 5 further includes a third light absorption anisotropic layer POL3 containing a third dichroic dye. The third light absorption anisotropic layer POL3 has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength λ3 different from the first wavelength λ1 and the second wavelength λ2, and has a third absorption axis A3 that shows the first light absorption characteristic along one direction. Fig.10 The polarizing plate 5 shown, similarly to the polarizing plate 4 , outputs first linear polarized light L1 , second linear polarized light L2 , and third linear polarized light L3 having mutually different polarization directions when the incident light L0 of non-polarized light is incident.

[0152] like Fig.10 As shown, in the polarizing plate 5 of this example, the third light absorption anisotropic layer POL3, the first light absorption anisotropic layer POL1, the first phase difference layer R1 and the second light absorption anisotropic layer POL2 are stacked in this order from the light incident side. Fig.10 As shown, the first light absorption anisotropic layer POL1, the second light absorption anisotropic layer POL2 and the third light absorption anisotropic layer POL3 are arranged in a manner that the first absorption axis A1, the second absorption axis A2 and the third absorption axis A3 are not parallel to each other. Then, the third light absorption anisotropic layer POL3 is arranged in a manner that the first absorption axis A1 and the third absorption axis A3 are orthogonal to each other with respect to the first light absorption anisotropic layer POL1.

[0153] In the polarizing plate 5, the relationship between the first phase difference layer R1 and the second light absorption anisotropic layer POL2 is the same as that of the polarizing plate 3. That is, in the polarizing plate 5, the first slow axis S1 and the second absorption axis A2 are orthogonal, and the above-mentioned formula E1 is satisfied. Therefore, the phase difference given to the first wavelength λ1 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the first phase difference layer R1.

[0154] Moreover, in the polarizer 5, when the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer POL2 is set to ReP2(λ3), and the phase difference generated in the light of the third wavelength λ3 passing through the first phase difference layer R1 is set to ReR1(λ3), the following formula E4 is satisfied.

[0155] ReP2(λ3) / ReR1(λ3)=1±0.2 E4

[0156] The above formula E4 means that the phase difference ReP2 (λ3) generated in the light of the third wavelength λ3 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the phase difference ReR1 (λ3) generated in the light of the third wavelength λ3 transmitted through the first phase difference layer R1. By arranging the first slow axis S1 of the first phase difference layer R1 and the second absorption axis A2 of the second light absorption anisotropic layer POL2 to be orthogonal, the phase difference given to the light of the third wavelength λ3 in the second light absorption anisotropic layer POL2 is offset by the first phase difference layer R1.

[0157] An example of the wavelength dependence of the phase difference of the second light absorption anisotropic layer POL2 and the phase difference of the first phase difference layer R1 in the polarizing plate 5 is shown in FIG. Fig.11 .like Fig.11 As shown, in the polarizer 5, the phase difference ReP2(λ1) of the second light absorption anisotropic layer POL2 with respect to the first wavelength λ1 is substantially equal to the phase difference ReR1(λ1) of the first phase difference layer R1 with respect to the first wavelength λ1, and the phase difference ReP2(λ3) of the second light absorption anisotropic layer POL2 with respect to the third wavelength λ3 is substantially equal to the phase difference ReR1(λ3) of the first phase difference layer R1 with respect to the third wavelength λ3.

[0158] When the incident light L0 including the non-polarized light of the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 is incident on the polarizer 5 from the third light absorption anisotropic layer POL3 side, the light of the first wavelength λ1 is output as the first linear polarized light L1, the light of the second wavelength λ2 is output as the second linear polarized light L2 in a direction different from the first linear polarized light L1, and the light of the third wavelength λ3 is output as the third linear polarized light L3 in a direction different from the first linear polarized light L1 and the second linear polarized light L2. That is, the polarizer 5 into which the incident light L0 is incident converts the incident light L0 into the light including the first linear polarized light L1, the second linear polarized light L2 and the third linear polarized light L3.

[0159] refer to Fig.10 The table in will explain the effect of polarizing plate 5 in more detail. Fig.10 ] represents the polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 before incidence and after transmission through each layer.

[0160] The incident light L0 enters the polarizing plate 5 from the third light absorption anisotropic layer POL3 side. The polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 are as follows: Fig.10 The "before incident" in the table shows non-polarized light.

[0161] If the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 are each Fig.10 The effect of the polarizing plate 5 of the present example on the incident light L0 will be described as follows.

[0162] The polarizing plate 5 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the first wavelength λ1. Therefore, Fig.10 As shown in "After passing through POL3" in the table of FIG. 1 , the light of the first wavelength λ1 passes through the third light absorption anisotropic layer POL3 in a non-polarized state. Then, the light of the first wavelength λ1 enters the first light absorption anisotropic layer POL1 in a non-polarized state. In the first light absorption anisotropic layer POL1, the polarization component along the first absorption axis A1 of the light of the first wavelength λ1 is absorbed. As a result, Fig.10 As shown in "After transmission POL1" in the table, the light of the first wavelength λ1 that has transmitted the first light absorption anisotropic layer POL1 becomes linearly polarized light in a direction orthogonal to the first absorption axis A1. Then, the light of the first wavelength λ1 is incident on the first phase difference layer R1 as linearly polarized light. The polarization direction of the linearly polarized light of the first wavelength λ1 is neither parallel to nor orthogonal to the first slow axis S1 of the first phase difference layer R1. Therefore, for the linearly polarized light of the first wavelength λ1 that is incident on the first phase difference layer R1, a phase difference ReR1(λ1) is imparted in the first phase difference layer R1. Therefore, as Fig.10 As shown in "After transmission R1" in the table, the linearly polarized light of the first wavelength λ1 becomes elliptically polarized light after passing through the first phase difference layer R1. Then, the light of the first wavelength λ1 is incident on the second light absorption anisotropic layer POL2 as elliptically polarized light. In the second light absorption anisotropic layer POL2, the second light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the second light absorption anisotropic layer POL2 imparts a phase difference ReP2(λ1) to the elliptically polarized light of the first wavelength λ1. As described above, the phase difference ReP2(λ1) is equivalent to the phase difference ReR1(λ1) (satisfying formula E1), and is configured in such a way that the first slow axis S1 of the first phase difference layer R1 is orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference imparted to the light of the first wavelength λ1 in the first phase difference layer R1 is offset by the second light absorption anisotropic layer POL2. Thus, as Fig.10 As shown in "After passing through POL2" in the table, the light of the first wavelength λ1 that has passed through the second light absorption anisotropic layer POL2 is restored to the linear polarization light immediately after passing through the first light absorption anisotropic layer POL1. This linear polarization light is output from the polarizing plate 5 as the first linear polarization light L1.

[0163] The polarizing plate 5 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 and the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Fig.10 As shown in "After passing through POL3" and "After passing through POL1" in the table of FIG. 1 , the light of the second wavelength λ2 passes through the third light absorption anisotropic layer POL3 and the first light absorption anisotropic layer POL1 in a non-polarized state. Then, the light of the second wavelength λ2 incident on the first phase difference layer R1 is non-polarized light, so Fig.10 As shown in "After transmission R1" in the table of , the first phase difference layer R1 transmits the light of the second wavelength λ2 in a non-polarized state. Then, the light of the second wavelength λ2 enters the second light absorption anisotropic layer POL2 in a non-polarized state. Then, in the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 in the light of the second wavelength λ2 is absorbed. As a result, Fig.10 As shown in “after passing through POL2 ” in the table, the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 becomes the second linearly polarized light L2 in a direction orthogonal to the second absorption axis A2 .

[0164] The polarizing plate 5 acts on the light of the third wavelength λ3 in the incident light L0 as follows. In the third light absorption anisotropic layer POL3 into which the incident light L0 first enters, the polarization component along the third absorption axis A3 in the light of the third wavelength λ3 is absorbed. Fig.10As shown in "After transmission POL3" in the table of , the light of the third wavelength λ3 that has transmitted the third light absorption anisotropic layer POL3 becomes linearly polarized light in a direction orthogonal to the third absorption axis A3. Therefore, the light of the third wavelength λ3 is incident on the first light absorption anisotropic layer POL1 as linearly polarized light. In the first light absorption anisotropic layer POL1, the first light absorption anisotropy does not act on the light of the third wavelength λ3. In addition, the first absorption axis A1 is parallel to the polarization direction of the light of the third wavelength λ3, so the first light absorption anisotropic layer POL1 does not affect the polarization state of the linearly polarized light of the third wavelength λ3. Therefore, the light of the third wavelength λ3 does not change its polarization direction, but transmits the first light absorption anisotropic layer POL1 in the state of linearly polarized light. The light of the third wavelength λ3 is incident on the first phase difference layer R1 as linearly polarized light. The polarization direction of the third wavelength λ3 is neither parallel nor orthogonal to the first slow axis S1 of the first phase difference layer R1, so the linear polarized light of the third wavelength λ3 incident on the first phase difference layer R1 is given a phase difference ReR1(λ3) in the first phase difference layer R1. Therefore, the linear polarized light of the third wavelength λ3 becomes elliptically polarized light after passing through the first phase difference layer R1. Then, the third wavelength λ3 is incident on the second light absorption anisotropic layer POL2 as elliptically polarized light. In the second light absorption anisotropic layer POL2, the second light absorption anisotropy does not act on the light of the third wavelength λ3. On the other hand, the second light absorption anisotropic layer POL2 gives a phase difference ReP2(λ3) to the elliptically polarized light of the third wavelength λ3. As described above, the phase difference ReP2(λ3) is equal to the phase difference ReR1(λ3) (satisfying the formula E4), and the first slow axis S1 of the first phase difference layer R1 is arranged to be orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference given to the light of the third wavelength λ3 in the first phase difference layer R1 is offset by the second light absorption anisotropic layer POL2. Fig.10 As shown in "After transmission R1" in the table, the light of the third wavelength λ3 that has transmitted the second light absorption anisotropic layer POL2 is restored to the linear polarization light immediately after transmitting the first light absorption anisotropic layer POL1. This linear polarization light is output from the polarizing plate 5 as the third linear polarization light L3.

[0165] By the above-described operation, the polarizing plate 5 can convert the non-polarized incident light L0 into light including the first linearly polarized light L1 of the first wavelength λ1, the second linearly polarized light L2 of the second wavelength λ2, and the third linearly polarized light L3 of the third wavelength λ3.

[0166] In the polarizing plate 5 of this example, each layer is stacked and integrated, so it is easy to handle. In addition, according to the polarizing plate 5, the light of different wavelengths λ1, λ2 and λ3 in the incident non-polarized light L0 can be converted into linear polarized light in different directions by the above-mentioned action.

[0167] "Sixth Implementation Method"

[0168] Fig.12 The polarizing plate 6 of the sixth embodiment is schematically shown by disassembling the polarizing plate 6 for each layer. In fact, the polarizing plate 6 is integrated by laminating each layer on the support 10 similarly to the polarizing plates 1 to 4 .

[0169] The polarizing plate 6 of the sixth embodiment is similar to the polarizing plate 2 of the second embodiment, and includes the first light absorption anisotropic layer POL1, the first phase difference layer R1, and the second light absorption anisotropic layer POL2 in sequence. Then, the polarizing plate 6 further includes the third light absorption anisotropic layer POL3 containing the third dichroic dye. The third light absorption anisotropic layer POL3 has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength λ3 different from the first wavelength λ1 and the second wavelength λ2, and has a third absorption axis A3 that shows the third light absorption characteristic along one direction. Then, the third light absorption anisotropic layer POL3 is configured in such a way that the third absorption axis A3 intersects with the first absorption axis A1 and the second absorption axis A2. That is, the first absorption axis A1, the second absorption axis A2, and the third absorption axis A3 intersect with each other. In particular, in this example, the third light absorption anisotropic layer POL3 is configured in such a way that the third absorption axis A3 is orthogonal to the first absorption axis A1.

[0170] The polarizing plate 6 further includes a second phase difference layer R2 for imparting a phase difference to the transmitted light between the second light absorption anisotropic layer POL2 and the third light absorption anisotropic layer POL3. Fig.12 As shown, the polarizing plate 6 includes a first light absorption anisotropic layer POL1 , a first retardation layer R1 , a second light absorption anisotropic layer POL2 , a second retardation layer R2 , and a third light absorption anisotropic layer POL3 stacked in this order from the light incident side. Fig.12 The polarizing plate 6 shown, similarly to the polarizing plates 4 and 5 , outputs first linear polarized light L1 , second linear polarized light L2 , and third linear polarized light L3 having different polarization directions when the incident light L0 of non-polarized light is incident.

[0171] In the polarizing plate 6, the relationship between the first phase difference layer R1 and the second light absorption anisotropic layer POL2 is the same as that of the polarizing plate 2. That is, in the polarizing plate 6, the first slow axis S1 and the second absorption axis A2 are orthogonal, and the above-mentioned formula E1 is satisfied. Therefore, the phase difference given to the first wavelength λ1 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the first phase difference layer R1.

[0172] When the phase difference generated in the light of the second wavelength λ2 passing through the third light absorption anisotropic layer POL3 is set to ReP3(λ2), and the phase difference generated in the light of the second wavelength λ2 passing through the second phase difference layer R2 is set to ReR2(λ2), the second phase difference layer R2 satisfies the following formula E5.

[0173] ReP3(λ2) / ReR2(λ2)=1±0.2Formula E5

[0174] Then, the second retardation layer R2 is arranged so that the second slow axis S2 serving as the slow axis thereof is orthogonal to the third absorption axis A3.

[0175] The above formula E5 means that the phase difference ReP3(λ2) generated in the light of the second wavelength λ2 transmitted through the third light absorption anisotropic layer POL3 is substantially equal to the phase difference ReR2(λ2) generated in the light of the second wavelength λ2 transmitted through the second phase difference layer R2. By arranging the second slow axis S2 of the second phase difference layer R2 and the third absorption axis A3 of the third light absorption anisotropic layer POL3 in a manner orthogonal to each other, the phase difference given to the second wavelength λ2 in the third light absorption anisotropic layer POL3 is offset by the phase difference given in the second phase difference layer R2.

[0176] refer to Fig.12 The table in will explain the effect of polarizing plate 6 in more detail. Fig.12 ] represents the polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 before incidence and after transmission through each layer.

[0177] The incident light L0 enters the polarizing plate 5 from the third light absorption anisotropic layer POL3 side. The polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 are as follows: Fig.10 The "before incident" in the table shows non-polarized light.

[0178] If the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 are each Fig.12 The effect of the polarizing plate 6 of the present example on the incident light L0 will be described as follows.

[0179] The polarizing plate 6 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the polarization component along the first absorption axis A1 in the light of the first wavelength λ1 is absorbed. Fig.12 As shown in “after passing through POL1 ” in the table, the light having the first wavelength λ1 that has passed through the first light absorption anisotropic layer POL1 becomes linearly polarized light having a polarization direction orthogonal to the first absorption axis A1 .

[0180] The polarization direction of the first wavelength λ1 is neither parallel nor orthogonal to the first slow axis S1 of the first phase difference layer R1. Therefore, for the light of the first wavelength λ1 incident on the first phase difference layer R1 as linearly polarized light, a phase difference ReR1(λ1) is given in the first phase difference layer R1. Fig.12 As shown in "After transmission R1" in the table, the light of the first wavelength λ1 becomes elliptically polarized light after passing through the first phase difference layer R1. Then, the light of the first wavelength λ1 is incident on the second light absorption anisotropic layer POL2 as elliptically polarized light. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the second light absorption anisotropic layer POL2 imparts a phase difference ReP2(λ1) to the linearly polarized light of the first wavelength λ1. As described above, the phase difference ReP2(λ1) is equivalent to the phase difference ReR1(λ1) (satisfying formula E1), and is configured in such a way that the first slow axis S1 of the first phase difference layer R1 is orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference imparted to the light of the first wavelength λ1 in the first phase difference layer R1 is offset by the second light absorption anisotropic layer POL2. Thus, as Fig.12 As shown in “after passing through POL2 ” in the table, the light of the first wavelength λ1 that has passed through the second light absorption anisotropic layer POL2 returns to the linearly polarized light immediately after passing through the first light absorption anisotropic layer POL1 .

[0181] The second slow axis S2 of the second phase difference layer R2 is orthogonal to the polarization direction of the linear polarized light of the first wavelength λ1, so the second phase difference layer R2 does not act on the first wavelength λ1. Therefore, the light of the first wavelength λ1 passes through the second phase difference layer R2 while maintaining the polarization direction when incident on the second phase difference layer R2. In addition, in the third light absorption anisotropic layer POL3, the light absorption anisotropy does not act on the first wavelength λ1. In addition, the third absorption axis A3 is parallel to the polarization direction of the linear polarized light of the first wavelength λ1, so the third light absorption anisotropic layer POL3 does not affect the polarization state of the linear polarized light of the first wavelength λ1. Therefore, the linear polarized light of the first wavelength λ1 passes through the third light absorption anisotropic layer POL3 while maintaining the polarization direction when incident on the third light absorption anisotropic layer POL3. This linear polarized light is output from the polarizer 6 as the first linear polarized light L1.

[0182] The polarizing plate 6 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Fig.12As shown in "After passing through POL1" in the table of FIG. 1 , the second wavelength λ2 passes through the first light absorption anisotropic layer POL1 in a non-polarized state. The first phase difference layer R1 does not provide a substantial phase difference to the non-polarized light, so Fig.12 As shown in "After transmission R1" in the table of FIG. 1 , the light of the second wavelength λ2 incident as non-polarized light passes through the first phase difference layer R1 as non-polarized light. Then, the light of the second wavelength λ2 is incident on the second light absorption anisotropic layer POL2 as non-polarized light. In the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 of the light of the second wavelength λ2 is absorbed. As a result, Fig.12 As shown in “after passing through POL2 ” in the table, the light of the second wavelength λ2 that has passed through the second light absorption anisotropic layer POL2 becomes linearly polarized light in a direction orthogonal to the second absorption axis A2 .

[0183] The polarization direction of the linear polarization light of the second wavelength λ2 is neither parallel nor orthogonal to the second slow axis S2 of the second phase difference layer R2. Therefore, for the linear polarization light of the second wavelength λ2 incident on the second phase difference layer R2, a phase difference ReR2(λ2) is given in the second phase difference layer R2, as shown in FIG. Fig.12 As shown in "After transmission R2" in the table, after passing through the second phase difference layer R2, it becomes elliptically polarized light. In the third light absorption anisotropic layer POL3, the light absorption anisotropy does not act on the light of the second wavelength λ2. On the other hand, the third light absorption anisotropic layer POL3 imparts a phase difference ReP3(λ2) to the light of the second wavelength λ2. As described above, the phase difference ReP3(λ2) is equivalent to the phase difference ReR2(λ2) (satisfying formula E5), and is configured in a manner that the second slow axis S2 of the second phase difference layer R2 is orthogonal to the third absorption axis A3 of the third light absorption anisotropic layer POL3. Therefore, the phase difference imparted to the light of the second wavelength λ2 in the second phase difference layer R2 is offset by the third light absorption anisotropic layer POL3, and the light of the second wavelength λ2 that has transmitted the third light absorption anisotropic layer POL3 returns to the linearly polarized light just after transmitting the second light absorption anisotropic layer POL2. This linearly polarized light is output from the polarizing plate 6 as second linearly polarized light L2.

[0184] The polarizing plate 6 acts on the light of the third wavelength λ3 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the third wavelength λ3. Therefore, Fig.12 As shown in "After passing through POL1" in the table of FIG. 1 , the third wavelength λ3 passes through the first light absorption anisotropic layer POL1 in a non-polarized state. The first phase difference layer R1 does not provide a substantial phase difference to the non-polarized light, so Fig.12As shown in "After passing through R1" in the table of FIG. 1 , the light of the third wavelength λ3 incident as non-polarized light passes through the first phase difference layer R1 as non-polarized light. Moreover, in the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the third wavelength λ3. Therefore, Fig.12 As shown in "After passing through POL2" in the table of FIG. 1 , the light of the third wavelength λ3 incident as non-polarized light passes through the second light absorbing anisotropic layer POL2 as non-polarized light. In addition, the second phase difference layer R2 does not impart a substantial phase difference to the non-polarized light, so Fig.12 As shown in "After transmission R2" in the table, the light of the third wavelength λ3 incident as non-polarized light passes through the second phase difference layer R2 as non-polarized light. Then, the light of the third wavelength λ3 is incident on the third light absorption anisotropic layer POL3 as non-polarized light. In the third light absorption anisotropic layer POL3, the polarization component along the third absorption axis A3 of the light of the third wavelength λ3 is absorbed. As a result, Fig.12 As shown in “after passing through POL3 ” in the table, the light having the third wavelength λ3 that has passed through the third light absorption anisotropic layer POL3 becomes the third linearly polarized light L3 in a direction orthogonal to the third absorption axis A3 .

[0185] By the above-described operation, the polarizing plate 6 can convert the non-polarized incident light L0 into light including the first linearly polarized light L1 of the first wavelength λ1, the second linearly polarized light L2 of the second wavelength λ2, and the third linearly polarized light L3 of the third wavelength λ3.

[0186] The polarizing plate 6 of this example is easy to handle because each layer is stacked and integrated. In addition, the polarizing plate 6 can convert the light of different wavelengths λ1, λ2 and λ3 in the incident non-polarized light L0 into linear polarized light in different directions by the above-mentioned action.

[0187] "Seventh Implementation Method"

[0188] Fig.13 This is a diagram showing a polarizing plate 7 according to a seventh embodiment. In fact, the polarizing plate 7 is integrated by laminating each layer on a support 10, similarly to the polarizing plates 1 to 4.

[0189] The polarizer 7 of the seventh embodiment is similar to the polarizer 6 of the sixth embodiment, and includes the first light absorption anisotropic layer POL1, the first phase difference layer R1, the second light absorption anisotropic layer POL2, the second phase difference layer R2, and the third light absorption anisotropic layer POL3 in sequence. However, unlike the polarizer 6, the third light absorption anisotropic layer POL3 is configured in a manner that the first absorption axis A1 and the third absorption axis A3 are not orthogonal. That is, in this example, the first absorption axis A1, the second absorption axis A2, and the third absorption axis A3 are respectively intersecting (not parallel) with each other, and are not orthogonal. As an example, the angle formed by the first absorption axis A1 and the second absorption axis A2 is 60°, and the angle formed by the first absorption axis A1 and the third absorption axis A3 is 120°. Fig.13 The polarizing plate 7 shown in the figure outputs the first linear polarized light L1, the second linear polarized light L2 and the third linear polarized light L3 having different polarization directions when the incident light L0 of non-polarized light is incident, similarly to the polarizing plate 6. The functional difference between the polarizing plate 7 and the polarizing plate 6 lies in the polarization directions of the second linear polarized light L2 and the third linear polarized light L3, and in particular, in that the third linear polarized light L3 is not orthogonal to the first linear polarized light L1.

[0190] In the polarizing plate 7, the relationship between the first phase difference layer R1 and the second light absorption anisotropic layer POL2 is the same as that of the polarizing plate 2 and the polarizing plate 6. That is, in the polarizing plate 7, the first slow axis S1 and the second absorption axis A2 are orthogonal, and the above-mentioned formula E1 is satisfied. Therefore, the phase difference given to the light of the first wavelength λ1 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the first phase difference layer R1.

[0191] In polarizer 7, similarly to polarizer 6, second slow axis S2 and third absorption axis A3 are orthogonal and satisfy equation E5. Therefore, the phase difference given to light of second wavelength λ2 in third light absorption anisotropic layer POL3 is offset by the phase difference given in second phase difference layer R2.

[0192] Moreover, in the polarizer 7, when the phase difference generated in the light of the first wavelength λ1 passing through the third light absorption anisotropic layer POL3 is set to ReP3(λ1), and the phase difference generated in the light of the first wavelength λ1 passing through the second phase difference layer R2 is set to ReR2(λ1), the second phase difference layer R2 satisfies the following formula E6.

[0193] ReP3(λ1) / ReR2(λ1)=1±0.2 E6

[0194] The above formula E6 means that the phase difference ReP3 (λ1) generated in the light of the first wavelength λ1 transmitted through the third light absorption anisotropic layer POL3 is substantially equal to the phase difference ReR2 (λ1) generated in the light of the first wavelength λ1 transmitted through the second phase difference layer R2. Since the second slow axis S2 of the second phase difference layer R2 is configured to be orthogonal to the third absorption axis A3 of the third light absorption anisotropic layer POL3, the phase difference given to the first wavelength λ1 in the third light absorption anisotropic layer POL3 is offset by the phase difference given in the second phase difference layer R2. Thus, the difference between the polarizer 7 and the polarizer 6 is that the angle formed by the first absorption axis A1 and the third absorption axis A3 is not orthogonal and the second phase difference layer R2 satisfies the formula E5 and the formula E6.

[0195] An example of the wavelength dependence of the phase difference of the third light absorption anisotropic layer POL3 and the phase difference of the second phase difference layer R2 in the polarizing plate 7 is shown in FIG. Fig.14 .like Fig.14 As shown, in the polarizer 7, the phase difference ReP3(λ1) of the third light absorption anisotropic layer POL3 relative to the first wavelength λ1 is substantially equal to the phase difference ReR2(λ1) of the second phase difference layer R2 relative to the first wavelength λ1, and the phase difference ReP3(λ2) of the third light absorption anisotropic layer POL3 relative to the second wavelength λ2 is substantially equal to the phase difference ReR2(λ2) of the second phase difference layer R2 relative to the second wavelength λ2.

[0196] When the incident light L0 including the non-polarized light of the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 is incident on the polarizing plate 7 from the first light absorption anisotropic layer POL1 side, the light of the first wavelength λ1 is output as the first linear polarized light L1, the second wavelength λ2 is output as the second linear polarized light L2 having a polarization direction different from that of the first linear polarized light L1, and the third wavelength λ3 is output as the third linear polarized light L3 having a polarization direction different from that of the first linear polarized light L1 and the second linear polarized light L2. That is, the polarizing plate 7 into which the incident light L0 is incident converts the incident light L0 into the light including the first linear polarized light L1, the second linear polarized light L2 and the third linear polarized light L3 having polarization directions different from each other.

[0197] refer to Fig.13 The table in will explain the effect of polarizing plate 7 in more detail. Fig.13 ] represents the polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 before incidence and after transmission through each layer.

[0198] The incident light L0 enters the polarizing plate 5 from the third light absorption anisotropic layer POL3 side. The polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 included in the incident light L0 are as follows: Fig.13 The "before incident" in the table shows non-polarized light.

[0199] If the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 are each Fig.13 The effect of the polarizing plate 7 of the present example on the incident light L0 will be described as follows.

[0200] The polarizing plate 7 acts on the light of the first wavelength λ1 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the polarization component along the first absorption axis A1 in the light of the first wavelength λ1 is absorbed. Fig.13 As shown in “after passing through POL1 ” in the table, the light having the first wavelength λ1 that has passed through the first light absorption anisotropic layer POL1 becomes linearly polarized light in a direction orthogonal to the first absorption axis A1 .

[0201] The light of the first wavelength λ1 is incident on the first phase difference layer R1 as linearly polarized light. The polarization direction of the linearly polarized light of the first wavelength λ1 is neither parallel nor orthogonal to the first slow axis S1 of the first phase difference layer R1. Therefore, for the light of the first wavelength λ1 incident on the first phase difference layer R1 as linearly polarized light, a phase difference ReR1(λ1) is given in the first phase difference layer R1. Therefore, as Fig.13 As shown in "After transmission R1" in the table, the linearly polarized light of the first wavelength λ1 becomes elliptically polarized light after passing through the first phase difference layer R1. Then, the light of the first wavelength λ1 is incident on the second light absorption anisotropic layer POL2 as elliptically polarized light. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the second light absorption anisotropic layer POL2 imparts a phase difference ReP2(λ1) to the elliptically polarized light of the first wavelength λ1. As described above, the first slow axis S1 of the first phase difference layer R1 is configured to be orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference imparted to the light of the first wavelength λ1 in the first phase difference layer R1 is offset by the second light absorption anisotropic layer POL 2. Therefore, as Fig.13 As shown in “after passing through POL2 ” in the table, the light of the first wavelength λ1 that has passed through the second light absorption anisotropic layer POL2 returns to the linearly polarized light immediately after passing through the first light absorption anisotropic layer POL1 .

[0202] The light of the first wavelength λ1 is incident on the second phase difference layer R2 as linearly polarized light. The second slow axis S2 of the second phase difference layer R2 is neither parallel nor orthogonal to the polarization direction of the first wavelength λ1. Therefore, for the linearly polarized light of the first wavelength λ1 incident on the second phase difference layer R2, a phase difference ReR2(λ1) is given in the second phase difference layer R2. Therefore, as Fig.13As shown in "After transmission R2" in the table, the linearly polarized light of the first wavelength λ1 becomes elliptically polarized light after passing through the second phase difference layer R2. Then, the light of the first wavelength λ1 is incident on the third light absorption anisotropic layer POL3 as elliptically polarized light. In the third light absorption anisotropic layer POL3, the light absorption anisotropy does not act on the light of the first wavelength λ1. On the other hand, the third light absorption anisotropic layer POL3 imparts a phase difference ReP3(λ1) to the elliptically polarized light of the first wavelength λ1. As described above, the phase difference ReP3(λ1) is equivalent to ReR2(λ1) (satisfying formula E6), and is configured in such a way that the second slow axis S2 of the second phase difference layer R2 is orthogonal to the third absorption axis A3 of the third light absorption anisotropic layer POL3. Therefore, the phase difference imparted to the light of the first wavelength λ1 in the second phase difference layer R2 is offset by the third light absorption anisotropic layer POL3. Therefore, as Fig.13 As shown in "After passing through POL3" in the table, the light of the first wavelength λ1 that has passed through the third light absorption anisotropic layer POL3 returns to the linear polarization light immediately after passing through the first light absorption anisotropic layer POL1. This linear polarization light is output from the polarizing plate 7 as the first linear polarization light L1.

[0203] The action of the polarizing plate 7 on the light of the second wavelength λ2 and the third wavelength λ3 in the incident light L0 is the same as that of the polarizing plate 6 , and therefore the details are omitted.

[0204] By the above-described operation, the polarizing plate 7 can convert the non-polarized incident light L0 into light including the first linearly polarized light L1 of the first wavelength λ1, the second linearly polarized light L2 of the second wavelength λ2, and the third linearly polarized light L3 of the third wavelength λ3.

[0205] In the polarizing plate 7 of this example, the first absorption axis A1 and the third absorption axis A3 intersect but are not orthogonal. In the polarizing plate 7, a phase difference can be given to the light of the first wavelength λ1 and the light of the second wavelength λ2 that pass through the second phase difference layer R2, and the phase difference cancels the phase difference generated when passing through the third light absorption anisotropic layer POL3. Even when the first absorption axis A1 and the third absorption axis A3 are not orthogonal, the first linear polarized light L1, the second linear polarized light L2, and the third linear polarized light L3 having polarization directions intersecting at an arbitrary angle can be output.

[0206] "Eighth Implementation Method"

[0207] Fig.15 This is a diagram showing a polarizing plate 8 according to an eighth embodiment. In fact, the polarizing plate 8 is integrated by laminating each layer on a support 10, similarly to the polarizing plates 1 to 4.

[0208] In the polarizing plate 8 of the eighth embodiment, the third phase difference layer R3 and the fourth phase difference layer R4 are provided between the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 arranged so that the first absorption axis A1 and the second absorption axis A2 intersect. The polarizing plate 8 is stacked in order from the incident direction of light, including the first light absorption anisotropic layer POL1, the third phase difference layer R3, the fourth phase difference layer R4 and the second light absorption anisotropic layer POL2.

[0209] In this example, the first light absorption anisotropic layer POL1 includes a fourth dichroic dye in addition to the first dichroic dye. The fourth dichroic dye is a dichroic dye different from the first dichroic dye and the second dichroic dye. Therefore, the first absorption axis A1 of the first light absorption anisotropic layer POL1 shows a fourth light absorption characteristic based on the fourth dichroic dye in addition to the first light absorption characteristic based on the first dichroic dye. The polarizing plate 8 outputs the first linear polarized light L1, the second linear polarized light L2, and the fourth linear polarized light L4 having different polarization directions for each of the first wavelength λ1, the second wavelength λ2, and the fourth wavelength λ4 when the incident light L0 of non-polarized light including the first wavelength λ1, the second wavelength λ2, and the fourth wavelength λ4 is incident.

[0210] The third phase difference layer R3 selectively imparts a phase difference that changes the polarization direction to any one of the first wavelength λ1 and the fourth wavelength λ4 output from the first light absorption anisotropic layer POL1. Therefore, in the third phase difference layer R3, when the linear polarized light of the first wavelength λ1 and the linear polarized light of the fourth wavelength λ4 are incident, one of the linear polarized lights is output without changing the polarization direction, and the other linear polarized light is changed in polarization direction and converted into a linear polarized light of a polarization direction different from that when it was incident and output. In this example, as an example, the third phase difference layer R3 is described as a layer that selectively imparts a phase difference that changes the polarization direction to the linear polarized light of the fourth wavelength λ4. At this time, the third phase difference layer R3 does not impart a phase difference that changes the polarization direction to the linear polarized light of the first wavelength λ1. In this example, the third phase difference layer R3 is configured in such a way that the third slow axis S3 as its slow axis is tilted 22.5° relative to the axial direction of the first absorption axis A1. At this time, in the third phase difference layer R3, if the light of the fourth wavelength λ4 is incident as linearly polarized light, its polarization direction is rotated by 45° and converted into linearly polarized light inclined by 45° relative to the polarization direction at the time of incidence, and the light is transmitted. On the other hand, in the third phase difference layer R3, if the light of the first wavelength λ1 is incident as linearly polarized light, the light is transmitted while maintaining its polarization direction.

[0211] As the third retardation layer R3, for example, a wavelength selective polarization conversion element manufactured by ColorLink Japan, Ltd. can be used.

[0212] The fourth phase difference layer R4 imparts a phase difference to the transmitted light. Here, the phase difference generated in the first wavelength λ1 transmitted through the fourth phase difference layer R4 is set to ReR4(λ1), and the phase difference generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer is set to ReP2(λ1). Furthermore, the phase difference generated in the fourth wavelength λ4 transmitted through the fourth phase difference layer R4 is set to ReR4(λ4), and the phase difference generated in the fourth wavelength λ4 transmitted through the second light absorption anisotropic layer is set to ReP2(λ4). At this time, the fourth phase difference layer R4 satisfies at least one of the following E7-1 and E7-2.

[0213] ReP2(λ1) / ReR4(λ1)=1±0.2 Formula E7-1

[0214] ReP2(λ4) / ReR4(λ4)=1±0.2 E7-2

[0215] Then, the fourth retardation layer R4 is arranged so that the fourth slow axis S4 serving as the slow axis thereof is orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2 .

[0216] The above formula E7-1 means that the phase difference ReP2(λ1) generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the phase difference ReR4(λ1) generated in the light of the first wavelength λ1 transmitted through the fourth phase difference layer R4. When the formula E7-1 is satisfied, the phase difference given to the light of the first wavelength λ1 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the fourth phase difference layer R4 by configuring the fourth slow axis S4 of the fourth phase difference layer R4 to be orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2.

[0217] The above formula E7-2 means that the phase difference ReP2(λ4) generated in the light of the fourth wavelength λ4 transmitted through the second light absorption anisotropic layer POL2 is substantially equal to the phase difference ReR4(λ4) generated in the light of the fourth wavelength λ4 transmitted through the fourth phase difference layer R4. When formula E7-2 is satisfied, the phase difference given to the light of the fourth wavelength λ4 in the second light absorption anisotropic layer POL2 is offset by the phase difference given in the fourth phase difference layer R4 by configuring the fourth slow axis S4 of the fourth phase difference layer R4 to be orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2.

[0218] When the first absorption axis A1 and the second absorption axis A2 are orthogonal, the fourth phase difference layer R4 only needs to satisfy one of the above formulas E7-1 and E7-2. On the other hand, when the first absorption axis A1 and the second absorption axis A2 are not orthogonal, the fourth phase difference layer R4 satisfies both of the above formulas E7-1 and E7-2.

[0219] As an example, Fig.15 In the polarizing plate 8 shown, the first absorption axis A1 and the second absorption axis A2 are orthogonal to each other, and the fourth retardation layer R4 satisfies the formula E7-2.

[0220] When the incident light L0 including the non-polarized light of the first wavelength λ1, the second wavelength λ2 and the fourth wavelength λ4 is incident on the polarizing plate 8, the light of the first wavelength λ1 is output as the first linear polarized light L1 whose polarization direction is orthogonal to the first absorption axis A1, the light of the second wavelength λ2 is output as the second linear polarized light L2 whose polarization direction is orthogonal to the second absorption axis A2, and the light of the fourth wavelength λ4 is output as the fourth linear polarized light L4 whose polarization direction is different from the polarization directions of the first linear polarized light L1 and the second linear polarized light L2. That is, the polarizing plate 8 converts the incident light L0 into the light including the first linear polarized light L1, the second linear polarized light L2 and the fourth linear polarized light L4.

[0221] refer to Fig.15 The table in will explain the effect of polarizing plate 8 in more detail. Fig.15 ] indicates the polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the fourth wavelength λ4 included in the incident light L0 before incidence and after transmission through each layer.

[0222] The incident light L0 enters the polarizing plate 8 from the first light absorption anisotropic layer POL1 side. The polarization states of the light of the first wavelength λ1, the second wavelength λ2, and the fourth wavelength λ4 included in the incident light L0 are as follows: Fig.15 The "before incident" in the table shows non-polarized light.

[0223] If the first wavelength λ1, the second wavelength λ2 and the fourth wavelength λ4 are each Fig.15 The effect of the polarizing plate 8 of the present example on the incident light L0 will be described as follows.

[0224] The polarizing plate 8 acts on the light of the first wavelength λ1 and the fourth wavelength λ4 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the polarization component along the first absorption axis A1 of the light of the first wavelength λ1 and the fourth wavelength λ4 is absorbed. Fig.15As shown in "After passing through POL1" in the table of FIG. 1 , the light of the first wavelength λ1 and the light of the fourth wavelength λ4 that have passed through the first light absorption anisotropic layer POL1 become linearly polarized light in a direction orthogonal to the first absorption axis A1. That is, the light of the first wavelength λ1 and the light of the fourth wavelength λ4 that have passed through the first light absorption anisotropic layer POL1 are linearly polarized light in the same polarization direction.

[0225] like Fig.15 As shown in "After transmission R3" in the table, the third phase difference layer R3 allows the linear polarization light of the first wavelength λ1 to be directly transmitted. Then, the first wavelength λ1 is incident on the fourth phase difference layer R4 as linear polarization light. The fourth slow axis S4, which is the slow axis of the fourth phase difference layer R4, is orthogonal to the polarization direction of the linear polarization light of the first wavelength λ1 just after passing through the third phase difference layer R3, and therefore does not give a substantial phase difference to the linear polarization light of the first wavelength λ1. Therefore, as Fig.15 As shown in "After transmission R4" in the table of FIG. 1 , the fourth phase difference layer R4 transmits the linear polarized light of the first wavelength λ1 while maintaining the polarization direction. Then, in the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the first wavelength λ1. Therefore, Fig.15 As shown in "After passing through POL2" in the table of FIG. 1 , the linearly polarized light of the first wavelength λ1 passes through the second light absorption anisotropic layer POL2 while maintaining its polarization direction. The linearly polarized light is output from the polarizing plate 8 as the first linearly polarized light L1.

[0226] On the other hand, Fig.15 As shown in "After transmission R3" in the table, the third phase difference layer R3 rotates the polarization direction by 45° to transmit the linearly polarized light of the fourth wavelength λ4. That is, the light of the fourth wavelength λ4 after transmitting the third phase difference layer R3 becomes a linearly polarized light with a polarization direction that forms an angle of 45° with the polarization direction of the linearly polarized light of the first wavelength λ1 after transmitting the third phase difference layer R3. Then, the fourth wavelength λ4 enters the fourth phase difference layer R4 as a linearly polarized light. The fourth slow axis S4, which is the slow axis of the fourth phase difference layer R4, is neither parallel nor orthogonal to the linearly polarized light of the fourth wavelength λ4 just after transmitting the third phase difference layer R3. Therefore, the fourth phase difference layer R4 imparts a phase difference ReR4 (λ4) to the transmitted linearly polarized light of the fourth wavelength λ4. Therefore, as Fig.15As shown in "After transmission R4" in the table, the light of the fourth wavelength λ4 becomes elliptically polarized light after transmitting the fourth phase difference layer R4. In the second light absorption anisotropic layer POL2, the light absorption anisotropy does not act on the light of the fourth wavelength λ4. On the other hand, the second light absorption anisotropic layer POL2 imparts a phase difference ReP2(λ4) to the elliptically polarized light of the fourth wavelength λ4. As described above, the phase difference ReP2(λ4) is equivalent to the phase difference ReR4(λ4) (satisfying formula E7-2), and is configured in a manner that the fourth slow axis S4 of the fourth phase difference layer R4 is orthogonal to the second absorption axis A2 of the second light absorption anisotropic layer POL2. Therefore, the phase difference imparted to the light of the fourth wavelength λ4 in the fourth phase difference layer R4 is offset by the second light absorption anisotropic layer POL2. Therefore, as Fig.15 As shown in "After passing through POL2" in the table, the light of the fourth wavelength λ4 that has passed through the second light absorption anisotropic layer POL4 returns to the linear polarization light immediately after passing through the third phase difference layer R3. This linear polarization light is output from the polarizing plate 8 as the fourth linear polarization light L4.

[0227] The polarizing plate 8 acts on the light of the second wavelength λ2 in the incident light L0 as follows. In the first light absorption anisotropic layer POL1 into which the incident light L0 first enters, the light absorption anisotropy does not act on the light of the second wavelength λ2. Therefore, Fig.15 As shown in "After passing through POL1" in the table of FIG. 1 , the light of the second wavelength λ2 passes through the first light absorption anisotropic layer POL1 in a non-polarized state. The third phase difference layer R3 and the fourth phase difference layer R4 do not impart a substantial phase difference to the non-polarized light. Therefore, Fig.15 As shown in "After transmission R3" and "After transmission R4" in the table, the light of the second wavelength λ2 is transmitted through the third phase difference layer R3 and the fourth phase difference layer R4 in a non-polarized state. Then, the light of the second wavelength λ2 is incident on the second light absorption anisotropic layer POL2 in a non-polarized state. In the second light absorption anisotropic layer POL2, the polarization component along the second absorption axis A2 of the light of the second wavelength λ2 is absorbed. As a result, Fig.15 As shown in “after passing through POL2 ” in the table, the light with the second wavelength λ2 after passing through the second light absorption anisotropic layer POL2 becomes the second linearly polarized light L2 in a direction orthogonal to the second absorption axis A2 .

[0228] By the above-described operation, the polarizing plate 8 can convert the non-polarized incident light L0 into light including the first linearly polarized light L1 of the first wavelength λ1, the second linearly polarized light L2 of the second wavelength λ2, and the fourth linearly polarized light L4 of the fourth wavelength λ4.

[0229] The polarizing plate 8 of this example has a structure including two light absorption anisotropic layers POL1 and POL2 and can convert three different wavelengths into the first linear polarized light L1 , the second linear polarized light L2 , and the fourth linear polarized light L4 having mutually different polarization directions.

[0230] As described above, the polarizing plate of the present invention can be easily handled and can convert a plurality of different wavelengths of light into linearly polarized light having different polarization directions.

[0231] In addition, in each of the above embodiments, polarizers 1 to 8 having 2 or 3 light absorption anisotropic layers are described, but the number of stacked light absorption anisotropic layers is not limited to 2 or 3 layers. The polarizer of the present invention may be a structure having 4 or more light absorption anisotropic layers. By stacking 4 or more light absorption anisotropic layers having different absorption maximum wavelengths, and adjusting the inclination of the absorption axis of each light absorption anisotropic layer, the inclination and phase difference of the slow axis of the phase difference layer between each light absorption anisotropic layer according to the examples of the first to eighth embodiments, a polarizer that converts linear polarized light into different polarization directions can be obtained.

[0232] Furthermore, when three or more light absorption anisotropic layers are provided, it is preferred that the relationship between adjacent absorption spectra and Figure 3 The relationship between the first absorption spectrum 11 and the second absorption spectrum 12 shown is the same. That is, it is preferred that the absolute value of the difference between the wavelengths of the absorption maximum wavelengths of adjacent absorption spectra is greater than the average value of the half-width at half maximum of the adjacent absorption spectra. With respect to multiple absorption spectra, the smaller the overlap of each absorption spectrum, the higher the polarization performance that can be obtained, and therefore it is preferred.

[0233] Even in the case of a polarizer capable of converting three or more wavelengths into linear polarized light of mutually different polarization directions, these wavelengths are not limited. It can be light in the visible light region, or light in the near-infrared light region (700 nm or more and 1500 nm or less). Alternatively, it can be light with a portion of wavelengths in the visible light region and another portion of wavelengths in the near-infrared light region.

[0234] Furthermore, in the polarizing plate of the present invention, each light absorption anisotropic layer may contain two or more dichroic dyes, as in the first light absorption anisotropic layer of the eighth embodiment. Figure 3The first absorption spectrum 11 and the second absorption spectrum shown are examples when the first light absorption anisotropic layer POL1 and the second light absorption anisotropic layer POL2 each include a dichroic dye. The absorption spectrum of the light absorption anisotropic layer including a plurality of dichroic dyes becomes an absorption spectrum obtained by adding a plurality of absorption spectra based on a plurality of dichroic dyes. Therefore, the absorption spectrum of the light absorption anisotropic layer including a plurality of dichroic dyes does not necessarily have a single peak. That is, the absorption spectrum of the first light absorption anisotropic layer POL1, the second light absorption anisotropic layer POL2 or the third light absorption anisotropic layer POL3 may have a plurality of peaks. In the case where the absorption spectrum of the light absorption anisotropic layer has a plurality of peaks, as in the case of the eighth embodiment described above, when a polarizing plate is provided that can output the wavelengths representing the respective peaks as light having polarization directions different from each other, the wavelengths of the respective peaks are treated as absorption maximum wavelengths. Furthermore, the light absorption spectrum of the first light absorption anisotropic layer POL1, the second light absorption anisotropic layer POL2, or the third light absorption anisotropic layer POL3 can show a substantially uniform high absorbance (for example, an intensity within a range of about ±10%) over a wide wavelength region by adding a plurality of absorption spectra based on a plurality of dichroic pigments. With respect to the light absorption anisotropic layer having such an absorption spectrum showing a substantially uniform absorbance over a wide wavelength region, any wavelength in the wavelength region can be treated as an absorption maximum wavelength. For example, when the first light absorption anisotropic layer POL1 has such an absorption spectrum showing a substantially uniform absorbance over a wide wavelength region, any wavelength to be output as linearly polarized light can be set as the first wavelength. Furthermore, for example, when the first light absorption anisotropic layer POL1 has such an absorption spectrum showing a substantially uniform absorbance over a wide wavelength region, any two wavelengths in the wavelength region can be set as the first wavelength and the fourth wavelength to be output as linearly polarized light of mutually different polarization directions.

[0235] Furthermore, the polarizing plate of the present invention may include a C plate having no in-plane phase difference in addition to the phase difference layers R1 to R4 having an in-plane phase difference.

[0236] The following describes usage examples of the polarizing plate of the present invention. Fig.16 Schematically shows a polarizing plate (as an example, Fig.12 6) shown in FIG. The multispectral camera 40 includes an optical system 50 and an image sensor 60. In addition, the multispectral camera 40 includes a control driver, an input / output interface, a computer, a display, etc., which are not shown. The multispectral camera 40 is an example of an imaging device that generates and outputs a multispectral image of a subject 38 by splitting light incident from the subject 38 into a plurality of different wavelengths and capturing the light.

[0237] The optical system 50 includes a first lens 52, a polarizing plate 6, and a second lens 56. The first lens 52, the polarizing plate 6, and the second lens 56 are arranged in order along the optical axis OA from the side of the subject 38 to the side of the image sensor 60. The first lens 52 collimates light (hereinafter referred to as "subject light") obtained by reflecting light emitted from a light source (not shown) from the subject 38 and makes it incident on the polarizing plate 6. The second lens 56 collects the subject light that has passed through the polarizing plate 6 and forms an image on the light receiving surface of the photoelectric conversion element provided in the image sensor 60.

[0238] The polarizing plate 6 has a first light absorption anisotropic layer POL1, a first phase difference layer R1, a second light absorption anisotropic layer POL2, a second phase difference layer R2, and a third light absorption anisotropic layer POL3 arranged in order from the light incident side. The polarizing plate 6 is arranged so that the light incident surface is orthogonal to the optical axis OA. As described above, in the polarizing plate 6, when the incident light L0 as non-polarized light of the subject light is incident, the first linear polarized light L1 of the first wavelength λ1, the second linear polarized light L2 of the second wavelength λ2, and the third linear polarized light L3 of the third wavelength λ3 are output. The polarization directions of the first linear polarized light L1 to the third linear polarized light L3 are different.

[0239] The first wavelength λ1 is converted into the first linear polarized light L1 of the first polarization direction α1, the second wavelength λ2 is converted into the second linear polarized light L2 of the second polarization direction α2, and the third wavelength λ3 is converted into the third linear polarized light L3 of the third polarization direction α3. Here, when the first polarization direction α1 is used as a reference and the angle is set to 0°, the second polarization direction α2 is an angle of 45°, and the third polarization direction α3 is an angle of 90°.

[0240] The image sensor 60 includes a photoelectric conversion element 62 and a signal processing circuit 68. As an example, the image sensor 60 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0241] The photoelectric conversion element 62 includes a pixel layer 63 and a polarization filter layer 66. Fig.16 Schematic structures of the pixel layer 63 and the polarization filter layer 66 are shown in FIG. The pixel layer 63 has a plurality of pixel blocks 65 arranged in a matrix, each of which is composed of two pixels 64A to 64D in the vertical direction and two pixels in the horizontal direction, for a total of four pixels. Fig.16 , only the pixels 64A to 64D of one pixel block 65 are shown. Each of the pixels 64A to 64D is a physical pixel having a photodiode, and performs photoelectric conversion on received light and outputs an electrical signal corresponding to the amount of received light.

[0242] The photoelectric conversion element 62 outputs the electric signals output from the pixels 64A to 64D as image data to the signal processing circuit 68. The signal processing circuit 68 digitizes the analog image data input from the photoelectric conversion element 62.

[0243] The polarization filter layer 66 has a first polarizer 66A, a second polarizer 66B, and a third polarizer 66C. The transmission axis of the first polarizer 66A is set to an angle of 0°, and transmits the first linear polarized light L1 of the first polarization direction α1. The transmission axis of the second polarizer 66B is set to an angle of 45°, and transmits the second linear polarized light L2 of the second polarization direction α2. The transmission axis of the third polarizer 66C is set to an angle of 90°, and transmits the third linear polarized light L3 of the third polarization direction α3. Here, as an example, two first polarizers 66A, one second polarizer 66B, and one third polarizer 66C are allocated to one pixel block 65.

[0244] The first linear polarized light L1 outputted from the polarizing plate 6 in the incident light L0, which is the subject light reflected by the subject 38, is transmitted through the first polarizer 66A and is received by the pixels 64A and 64C. The second linear polarized light L2 outputted from the polarizing plate 6 in the incident light L0 is transmitted through the second polarizer 66B and is received by the pixel 64B. Then, the third linear polarized light L3 outputted from the polarizing plate 6 in the incident light L0 is transmitted through the third polarizer 66C and is received by the pixel 64D.

[0245] The signal processing circuit 68 digitizes the light receiving signal of the first linear polarized light L1 based on the first wavelength λ1, the light receiving signal of the second linear polarized light L2 based on the second wavelength λ2, and the light receiving signal of the third linear polarized light L3 based on the third wavelength λ3, and outputs them to a computer (not shown). Thus, by performing image processing in the computer, an image based on the light of the first wavelength λ1, an image based on the light of the second wavelength λ2, and an image based on the light of the third wavelength λ3 can be obtained.

[0246] Example

[0247] Below, embodiment and comparative example are given to more specifically describe the feature of the present invention. About the material shown in the following examples, usage, ratio, processing content and processing step, as long as do not depart from the purpose of the present invention, then can be appropriately changed.Therefore, the scope of the present invention should not be interpreted in a restrictive manner by the specific example shown below.

[0248] <Synthesis>

[0249] Rod-shaped compound I-1 and dichroic dyes II-1 to II-5 having a hydrophilic group were synthesized by a known method. Rod-shaped compound I-1 is a high molecular weight (n is 2 or more), and has a number average molecular weight of 25,000 and a molecular weight distribution of 5.1. Rod-shaped compound I-1 exhibits lyotropic liquid crystal properties.

[0250] Rod-shaped compound I-1

[0251] [Chemical formula 1]

[0252]

[0253] Dichroic pigment II-1

[0254] [Chemical formula 2]

[0255]

[0256] Dichroic pigment II-2

[0257] [Chemical formula 3]

[0258]

[0259] Dichroic pigment II-3

[0260] [Chemical formula 4]

[0261]

[0262] Dichroic pigment II-4

[0263] [Chemical formula 5]

[0264]

[0265] Dichroic pigment II-5

[0266] [Chemical formula 6]

[0267]

[0268] <Example 1>

[0269] "Production of Polarizer E1"

[0270] An adhesive layer was formed by applying an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) on the surface of the light absorption anisotropic layer P1 of the light absorption anisotropic layer laminate TP1 described later. Then, the light absorption anisotropic layer laminate TP2 described later was laminated in such a manner that the adhesive layer and the light absorption anisotropic layer P2 were in close contact, thereby obtaining the polarizer E1 of Example 1. In addition, the light absorption anisotropic layer P2 was laminated in such a manner that the angle formed by the absorption axis of the light absorption anisotropic layer P1 and the absorption axis of the light absorption anisotropic layer P2 became 90°. The polarizer E1 is a laminated body in which a cellulose acylate film T1, a light absorption anisotropic layer P1, an adhesive layer, a light absorption anisotropic layer P2 and a cellulose acylate film T1 are laminated in this order. The polarizing plate E1 is an example of the polarizing plate 1 according to the first embodiment. The light absorption anisotropic layer P1 corresponds to the first light absorption anisotropic layer POL1 , and the light absorption anisotropic layer P2 corresponds to the second light absorption anisotropic layer POL2 (see Table 2).

[0271] {Production of Cellulose Acylate Film T1}

[0272] (Preparation of Cellulose Ester Solution A-1)

[0273] The following composition was placed in a mixing tank, and each component was dissolved by stirring while heating to prepare a cellulose ester solution A-1.

[0274] Composition of cellulose ester solution A-1

[0275]

[0276] (Preparation of Matting Agent Dispersion Liquid B-1)

[0277] The following composition was placed in a disperser and stirred to dissolve each component to prepare a matting agent dispersion B-1.

[0278] [Composition of Matting Agent Dispersion Liquid B-1]

[0279]

[0280]

[0281] (Preparation of UV absorber solution CI)

[0282] The following composition was placed in another mixing tank, and each component was dissolved by stirring while heating to prepare an ultraviolet absorber solution CI.

[0283] [Composition of UV absorber solution CI]

[0284]

[0285] (UV-1)

[0286] [Chemical formula 7]

[0287]

[0288] (UV-2)

[0289] [Chemical formula 8]

[0290]

[0291] (Process for producing cellulose acylate film T1)

[0292] Ultraviolet absorber solution CI was added to a mixture of 94.6 parts by mass of cellulose ester solution A-1 and 1.3 parts by mass of matting agent dispersion B-1, so that the ultraviolet absorber (UV-1) and ultraviolet absorber (UV-2) were each 1.0 parts by mass per 100 parts by mass of cellulose acylate, and each component was dissolved while being heated and stirred thoroughly, thereby preparing a doping solution. The obtained doping solution was heated to 30°C and passed through a casting die, and cast onto a roller with a diameter of 3m, i.e., a mirror-finished stainless steel support. The surface temperature of the mirror-finished stainless steel support was set to -5°C, and the coating width was set to 1470mm. By rolling on the roller at a speed of 150m 3 The cast dope film was dried by blowing dry air at 34°C / min, and peeled from the drum in a state where the residual solvent was 150% when the solid content in the doped liquid film was 100%. During the peeling, the film was stretched 15% in the conveying direction (length direction). Then, the film was stretched by a pin tenter (specifically, the method of Japanese Patent Laid-Open No. 4-1009). Figure 3 The film was conveyed by holding both ends of the film in the width direction (i.e., in the direction perpendicular to the casting direction) with a pin tenter described in the specification. In addition, no stretching treatment was performed in the width direction of the film at this time. Furthermore, the film was further dried by conveying it between the rollers of the heat treatment device, thereby producing a cellulose acylate film T1. The produced long strip of cellulose acylate film T1 had a residual solvent content of 0.2%, a thickness of 60 μm, and an in-plane phase difference Re and a thickness direction phase difference Rth at a wavelength of 550 nm of 0.8 nm and 40 nm, respectively.

[0293] (Alkali saponification treatment)

[0294] After the cellulose acylate film T1 was passed through a dielectric heating roller at a temperature of 60° C. to raise the film surface temperature to 40° C., an alkali solution of the following composition was applied at a coating amount of 14 ml / m 2 using a bar coater. 2The film was coated on the tape surface and conveyed under a steam-type far-infrared heater manufactured by NORITAKE CO., LIMITED heated to 110°C for 10 seconds. Then, pure water was applied at 3 mL / m 2 Next, after water washing with a jet coater and dehydration with an air knife were repeated three times, the film was conveyed to a drying zone at 70° C. for 10 seconds for drying, thereby producing an alkali saponified cellulose acylate film T1.

[0295] [Alkaline solution composition]

[0296]

[0297] {Production of Light Absorption Anisotropic Layer Stack TP1}

[0298] A light absorption anisotropic layer P1 described later was formed on the cellulose acylate film T1, and a light absorption anisotropic layer laminate TP1 including the light absorption anisotropic layer P1 on the cellulose acylate film T1 was prepared.

[0299] (Formation of Light Absorption Anisotropic Layer P1)

[0300] A composition 1 for forming a light-absorbing anisotropic layer having the following composition was prepared. The composition 1 for forming a light-absorbing anisotropic layer is a composition showing lyotropic liquid crystal properties.

[0301] [Composition of Light Absorption Anisotropic Layer-Forming Composition 1]

[0302]

[0303] 5g of the light absorption anisotropic layer forming composition 1 prepared above and 20g of zirconium oxide microbeads with a diameter of 2mm were filled into a 45mL zirconium oxide container, and a planetary ball mill P-7classic line manufactured by Frisch GmbH was used to grind the mixture at a rotation speed of 300rpm for 50 minutes. The light absorption anisotropic layer forming composition 1 that had been grinded was applied to the alkali saponified surface of the cellulose acylate film T1 that had been treated with alkali saponification using a wire rod (moving speed: 100cm / s), and naturally dried. Next, the obtained coating was immersed in a 1mol / L calcium chloride aqueous solution for 5 seconds, washed with ion exchange water, and air-dried to fix the orientation state, thereby preparing a light absorption anisotropic layer P1 with a film thickness of 1μm. The absorption maximum wavelength of the light absorption anisotropic layer P1 was 960nm.

[0304] {Production of Light Absorption Anisotropic Layer Stack TP2}

[0305] In the preparation of the light absorption anisotropic layer laminate TP1, a light absorption anisotropic layer laminate TP2 in which the light absorption anisotropic layer P2 was laminated on the cellulose acylate film T1 was prepared in the same manner except that the light absorption anisotropic layer P1 was changed to a light absorption anisotropic layer P2 described later.

[0306] (Formation of Light Absorption Anisotropic Layer P2)

[0307] The light absorption anisotropic layer P2 was formed on the cellulose acylate film T1 by the same method as the light absorption anisotropic layer P1, except that the dichroic dye II-2 was changed to the aforementioned dichroic dye II-1 in the composition of the light absorption anisotropic layer forming composition 1. The absorption maximum wavelength of the light absorption anisotropic layer P2 was 850 nm.

[0308] <Example 2>

[0309] "Production of Polarizer E2"

[0310] In the preparation of the polarizer E1 of Example 1, the light absorption anisotropic layer laminate TP1 was changed to the light absorption anisotropic layer laminate TP3 described later, and the polarizer E2 of Example 2 was prepared by the same method as Example 1. The polarizer E2 is a laminate formed by laminating the cellulose acylate film T1, the light absorption anisotropic layer P3, the adhesive layer, the light absorption anisotropic layer P2 and the cellulose acylate film T1 in this order. The polarizer E2 is an example of the polarizer 1 of the first embodiment, the light absorption anisotropic layer P3 is equivalent to the first light absorption anisotropic layer POL1, and the light absorption anisotropic layer P2 is equivalent to the second light absorption anisotropic layer POL2 (refer to Table 2).

[0311] {Production of light-absorbing anisotropic layer stack TP3}

[0312] In the preparation of the light absorption anisotropic layer laminate TP1, a light absorption anisotropic layer laminate TP3 in which the light absorption anisotropic layer P2 was laminated on the cellulose acylate film T1 was prepared in the same manner except that the light absorption anisotropic layer P1 was changed to a light absorption anisotropic layer P3 described later.

[0313] (Formation of Light Absorption Anisotropic Layer P3)

[0314] In the formation of the light absorption anisotropic layer P1 in Example 1, a light absorption anisotropic layer P3 was formed on the cellulose acylate film T1 by the same method as in Example 1, except that the light absorption anisotropic layer-forming composition 1 was changed to the light absorption anisotropic layer-forming composition 3 described below. The absorption maximum wavelength of the light absorption anisotropic layer P3 was 960 nm.

[0315] [Composition of Light Absorption Anisotropic Layer-Forming Composition 3]

[0316]

[0317] <Example 3>

[0318] "Production of Polarizer E3"

[0319] An adhesive layer was formed by applying an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) to the surface of the cellulose acylate film T1 of the light absorbing anisotropic layer laminate TP1 on which the light absorbing anisotropic layer P1 was not formed. Then, an optically anisotropic layer laminate TO1 described later in which an optically anisotropic layer O1 was formed on the cellulose acylate film T1 via an oriented film 1 was laminated in such a manner that the adhesive layer and the optically anisotropic layer O1 were closely attached. Then, the cellulose acylate film T1 and the oriented film 1 were peeled off from the optically anisotropic layer O1 to obtain a laminate. Next, an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer O1 of the obtained laminate, which was exposed by peeling off the cellulose acylate film T1 and the oriented film 1, to form an adhesive layer, and the light absorbing anisotropic layer laminate TP2 was laminated in such a manner that the adhesive layer and the light absorbing anisotropic layer P2 were closely attached. Then, the cellulose acylate film T1 of the light absorbing anisotropic layer laminate TP2 was peeled off, thereby obtaining a polarizing plate E3 of Example 3.

[0320] Polarizer E3 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O1, an adhesive layer, and a light absorption anisotropic layer P2. Polarizer E3 is an example of the polarizer 2 of the second embodiment, the light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O1 is equivalent to the first phase difference layer R1, and the light absorption anisotropic layer P2 is equivalent to the second light absorption anisotropic layer POL2 (see Table 2).

[0321] In addition, the in-plane phase difference Re of the optical anisotropic layer O1 at the absorption maximum wavelength (corresponding to the first wavelength λ1) of 960 nm of the optical absorption anisotropic layer P1 is 244 nm, and the in-plane phase difference Re of the optical absorption anisotropic layer P2 is 249 nm. That is, the phase difference ReR1(λ1)=244 nm generated in the light of the first wavelength λ1 transmitted through the first phase difference layer R1 is equivalent to the phase difference ReP2(λ1)=249 nm generated in the light of the first wavelength λ1 transmitted through the second optical absorption anisotropic layer POL2, and the formula E1 is satisfied.

[0322] In the polarizing plate E3, the absorption axis of the optical absorption anisotropic layer P1 (equivalent to the first absorption axis A1), the slow axis of the optical anisotropic layer O1 (equivalent to the first slow axis S1), and the absorption axis of the optical absorption anisotropic layer P2 (equivalent to the second absorption axis A2) are oriented at 0°, 150°, and 60°, respectively. The orientations of the first absorption axis A1, the first slow axis S1, and the second absorption axis A2 are 0°, 150°, and 60°, which means that the first absorption axis A1 is 0° (reference), the angle formed by the first absorption axis A1 and the first slow axis S1 is 150°, and the angle formed by the first absorption axis A1 and the second absorption axis A2 is 60°. The same is true in the following embodiments.

[0323] {Production of optically anisotropic layer laminate TO1}

[0324] An alignment film 1 described below was formed on a cellulose acylate film T1, and an optically anisotropic layer O1 was formed on the alignment film 1, thereby preparing an optically anisotropic layer laminate TO1 in which the alignment film 1 and the optically anisotropic layer O1 were sequentially laminated on the cellulose acylate film T1.

[0325] (Formation of Alignment Film 1)

[0326] The alkali saponified surface of the cellulose acylate film T1 was continuously coated with an alignment film coating liquid (A) having the following composition using a #14 wire bar. The coating film was dried with 60°C hot air for 60 seconds and further with 100°C hot air for 120 seconds.

[0327] [Composition of Alignment Film Coating Liquid (A)]

[0328]

[0329] Modified polyvinyl alcohol 1

[0330] [Chemical formula 9]

[0331]

[0332] (Formation of Optically Anisotropic Layer O1)

[0333] The oriented film 1 prepared as above is continuously subjected to a friction treatment. At this time, the length direction of the long film is parallel to the conveying direction, and the angle formed by the length direction of the film (conveying direction) and the rotation axis of the friction roller is set to 72.5°. If the length direction of the film (conveying direction) is set to 90°, when viewed from the oriented film 1 side, the rotation axis of the friction roller is located at -17.5°, with the width direction of the film as the reference (0°), and the counterclockwise direction is represented by a positive value. In other words, the position of the rotation axis of the friction roller is equivalent to the position of 72.5° counterclockwise rotation based on the length direction of the film.

[0334] An optically anisotropic layer coating liquid (A) containing a discotic liquid crystal (DLC) compound of the following composition was continuously coated on the above-made oriented film 1 using a wire bar. The film conveying speed (V) was set to 26 m / min. In order to dry the solvent of the coating liquid and mature the orientation of the DLC compound, it was heated with warm air at 115°C for 90 seconds, then heated with warm air at 80°C for 60 seconds, and UV (ultraviolet) irradiation was performed at 80°C (exposure: 70 mJ / cm 2 ), the orientation of the liquid crystal compound was fixed, thereby producing an optically anisotropic layer O1. The thickness of the optically anisotropic layer O1 is 2.3μm. It was confirmed that the average tilt angle of the disk surface of the DLC compound relative to the film surface was 90°, and the DLC compound was oriented vertically relative to the film surface. In addition, the angle of the slow axis is parallel to the rotation axis of the friction roller, and if the length direction of the film (conveying direction) is set to 90° (the width direction of the film is set to 0°, observed from the oriented film 1 side, with the width direction of the film as the reference (0°), and positive values ​​are used to represent the counterclockwise direction.), it is -17.5°.

[0335] [Composition of Optically Anisotropic Layer Coating Liquid (A)]

[0336]

[0337]

[0338] Discotic liquid crystal compound (A)

[0339] [Chemical formula 10]

[0340]

[0341] Discotic liquid crystal compound (B)

[0342] [Chemical formula 11]

[0343]

[0344] Pyridinium salt (A)

[0345] [Chemical formula 12]

[0346]

[0347] (Compound A)

[0348] [Chemical formula 13]

[0349]

[0350] (Polymer A)

[0351] [Chemical formula 14]

[0352]

[0353] (Polymer B)

[0354] [Chemical formula 15]

[0355]

[0356] In the above, a represents 90 and b represents 10.

[0357] (Polymer C)

[0358] [Chemical formula 16]

[0359]

[0360] <Example 4>

[0361] "Production of Polarizer E4"

[0362] In the preparation of the polarizing plate E3 of Example 3, the polarizing plate E4 of Example 4 was prepared by the same method as in Example 3, except that the light absorbing anisotropic layer laminate TP2 was changed to the light absorbing anisotropic layer laminate TP4 described later, and the optically anisotropic layer laminate TO1 including the optically anisotropic layer O1 was changed to the optically anisotropic layer laminate TO2 including the optically anisotropic layer O2 described later. In the preparation process of the polarizing plate E3, an adhesive layer was formed on the surface of the optically anisotropic layer O1, and the light absorbing anisotropic layer laminate TP2 was bonded so that the adhesive layer and the light absorbing anisotropic layer P2 were in close contact, and then the cellulose acylate film T1 of the light absorbing anisotropic layer laminate TP2 was peeled off. In contrast, in the production process of the polarizer E4, an adhesive layer is formed on the surface of the optically anisotropic layer O2, and after the light absorbing anisotropic layer stack TP4 is bonded to the oxygen barrier layer B1 described later in such a way that the adhesive layer is in close contact with the light absorbing anisotropic layer stack TP4, the cellulose acylate film T2 and the photo-alignment film PA1 are peeled off from the light absorbing anisotropic layer stack TP4.

[0363] Polarizer E4 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O2, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P4. Polarizer E4 is an example of the polarizer 2 of the second embodiment, the light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O2 is equivalent to the first phase difference layer R1, and the light absorption anisotropic layer P4 is equivalent to the second light absorption anisotropic layer POL2 (see Table 2).

[0364] In addition, the in-plane phase difference Re of the optical anisotropic layer O2 at the absorption maximum wavelength (first wavelength λ1) of 960 nm of the optical absorption anisotropic layer P1 is 489 nm, and the in-plane phase difference Re of the optical absorption anisotropic layer P4 is 482 nm. That is, the phase difference ReR1(λ1)=489 nm generated in the light of the first wavelength λ1 transmitted through the first phase difference layer R1 is equal to the phase difference ReP2(λ1)=482 nm generated in the light of the first wavelength λ1 transmitted through the second optical absorption anisotropic layer POL2, and the formula E1 is satisfied.

[0365] {Production of Cellulose Acylate Film T2}

[0366] (Preparation of Core Layer Cellulose Acylate Dope Liquid)

[0367] The following composition was placed in a stirring tank and stirred to dissolve the components, thereby preparing a cellulose acetate solution to be used as a cellulose acylate dope for the core layer.

[0368] [Core layer cellulose acylate doping liquid]

[0369]

[0370] Compound F

[0371] [Chemical formula 17]

[0372]

[0373] (Preparation of outer layer cellulose acylate doping solution)

[0374] 10 parts by mass of the following matting agent solution was added to 90 parts by mass of the above core layer cellulose acylate doping solution to prepare a cellulose acetate solution to be used as an outer layer cellulose acylate doping solution.

[0375] [Matting agent solution]

[0376]

[0377] (Process for producing cellulose acylate film T2)

[0378] After filtering the core layer cellulose acylate dope and the outer layer cellulose acylate dope using filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm, the core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides thereof are simultaneously cast in three layers from a casting port onto a drum (belt casting machine) at 20°C.

[0379] Next, the film was peeled from the roll in a state where the solvent content was about 20% by mass, and both ends of the film in the width direction were fixed with tenter clips, stretched in the transverse direction at a stretching ratio of 1.1 times, and dried.

[0380] Then, the film was further dried by conveying it between rollers of a heat treatment device to prepare an optical film (transparent support) having a thickness of 40 μm, which was referred to as cellulose acylate film T2. The in-plane retardation Re of the obtained cellulose acylate film T2 was 0 nm.

[0381] (Formation of Photo-Alignment Film PA1)

[0382] The following photo-alignment film-forming coating liquid was continuously coated on the cellulose acylate film T2 using a wire bar. The cellulose acylate film T2 with the coating film was dried with warm air at 140° C. for 120 seconds, and then the coating film was irradiated with polarized ultraviolet light (10 mJ / cm 2 , using an ultra-high pressure mercury lamp), thereby forming a photo-alignment film PA1. The thickness of the photo-alignment film PA1 was 0.5 μm.

[0383] [Coating liquid for forming a photo-alignment film]

[0384]

[0385]

[0386] Polymer PA-1

[0387] [Chemical formula 18]

[0388]

[0389] Acid Generator PAG-1

[0390] [Chemical formula 19]

[0391]

[0392] Stabilizer DIPEA

[0393] [Chemical formula 20]

[0394]

[0395] {Production of Light Absorption Anisotropic Layer Stack TP4}

[0396] The light absorption anisotropic layer P4 described later is formed on the photo alignment film PA1 formed on the cellulose acylate film T2, and the oxygen barrier layer B1 described later is further formed. Thus, a light absorption anisotropic layer laminate TP4 in which the cellulose acylate film T2, the photo alignment film PA1, the light absorption anisotropic layer P4 and the oxygen barrier layer B1 are laminated is prepared.

[0397] (Formation of Light Absorption Anisotropic Layer P4)

[0398] A light absorption anisotropic layer-forming composition 4 having the following composition was prepared. The light absorption anisotropic layer-forming composition 4 was continuously applied on the photo-alignment film PA1 using a wire bar to form a coating layer.

[0399] Next, the coating layer was heated at 140° C. for 15 seconds, and the coating layer was cooled to room temperature (23° C.).

[0400] Next, the mixture was heated at 80° C. for 60 seconds and cooled again to room temperature.

[0401] Then, an LED (light emitting diode) lamp (central wavelength 365nm) was used at an illumination of 200mW / cm 2 The coating layer is irradiated for 2 seconds under the irradiation conditions of , thereby curing the coating layer and forming a light absorption anisotropic layer P4 on the photo-alignment film PA1. The film thickness of the light absorption anisotropic layer P4 is 0.5 μm. The absorption wavelength of the light absorption anisotropic layer P4 is the entire visible light region. The light absorption anisotropic layer P4 contains the following three dichroic pigments C-1, M-1, and Y-1, each having a different absorption maximum wavelength. In the light absorption anisotropic layer P4, the absorption spectra of each dichroic pigment overlap, and high light absorption anisotropy is exerted throughout the entire visible light region.

[0402] [Composition of Light Absorption Anisotropic Layer-Forming Composition 4]

[0403]

[0404] Dichroic pigment C-1 (absorption maximum wavelength: 570nm)

[0405] [Chemical formula 21]

[0406]

[0407] Dichroic pigment M-1 (absorption maximum wavelength: 466nm)

[0408] [Chemical formula 22]

[0409]

[0410] Dichroic pigment Y-1 (absorption maximum wavelength: 417nm)

[0411] [Chemical formula 23]

[0412]

[0413] Liquid crystal compound L-1

[0414] [Chemical formula 24]

[0415]

[0416] Surfactant F-1

[0417] [Chemical formula 25]

[0418]

[0419] (Formation of oxygen barrier layer B1)

[0420] The coating layer was formed by continuously coating the oxygen barrier layer forming coating liquid of the following composition on the light absorption anisotropic layer P4 using a wire bar. Then, the coating layer was dried for 5 minutes with warm air at 80°C, thereby forming an oxygen barrier layer B1 containing polyvinyl alcohol (PVA) with a thickness of 1.0 μm. Thus, a light absorption anisotropic layer laminate TP4 having a cellulose acylate film T2, a photo-alignment film PA1, a light absorption anisotropic layer P4 and an oxygen barrier layer B1 in this order was obtained.

[0421] [Composition of coating liquid for forming oxygen barrier layer]

[0422]

[0423] Modified polyvinyl alcohol 2

[0424] [Chemical formula 26]

[0425]

[0426] {Production of optically anisotropic layer laminate TO2}

[0427] An alignment film 1 described below was formed on a cellulose acylate film T1, and an optically anisotropic layer O2 was formed on the alignment film 1, thereby preparing an optically anisotropic layer laminate TO2 in which the alignment film 1 and the optically anisotropic layer O2 were sequentially laminated on the cellulose acylate film T1.

[0428] (Formation of Optically Anisotropic Layer O2)

[0429] Two optically anisotropic layer stacks TO1 were prepared. An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer O1 of one of the two optically anisotropic layer stacks TO1 to form an adhesive layer, and the other optically anisotropic layer stack TO1 was bonded in such a way that the adhesive layer and the optically anisotropic layer O1 were closely attached. Thus, an optically anisotropic layer O2 formed by bonding two layers of optically anisotropic layers O1 via an adhesive layer was formed. In addition, when bonding the optically anisotropic layers O1 to each other, the slow axes of the two layers were made parallel.

[0430] Then, the cellulose acylate film T1 and the oriented film 1 of one of the optically anisotropic layer laminates TO1 were peeled off. Thus, an optically anisotropic layer laminate TO2 in which the oriented film 1 and the optically anisotropic layer O2 were laminated on the cellulose acylate film T1 was obtained.

[0431] <Example 5>

[0432] "Production of Polarizer E5"

[0433] An adhesive layer was formed by applying an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) to the surface of the cellulose acylate film T1 of the aforementioned optical absorption anisotropic layer laminate TP1 and the surface on which the optical absorption anisotropic layer P1 was not formed. The aforementioned optical anisotropic layer laminate TO1 was laminated in such a manner that the adhesive layer and the optical anisotropic layer O1 were in close contact. Then, the cellulose acylate film T1 and the orientation film 1 were peeled off from the optical anisotropic layer O1, thereby obtaining a laminate. An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optical anisotropic layer O1 of the obtained laminate, which was exposed by peeling off the cellulose acylate film T1 and the orientation film 1, to form an adhesive layer, and the aforementioned optical absorption anisotropic layer laminate TP2 was laminated in such a manner that the adhesive layer and the optical absorption anisotropic layer P2 were in close contact. Then, the cellulose acylate film T1 of the light absorbing anisotropic layer laminate TP2 was peeled off. An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the light absorbing anisotropic layer P2 of the obtained laminate, which was exposed by peeling off the cellulose acylate film T1, to form an adhesive layer, and an optical anisotropic layer laminate TO3 described later was bonded in such a manner that the adhesive layer and the optical anisotropic layer O3 were closely attached. Then, the cellulose acylate film T1 and the oriented film 1 were peeled off from the optical anisotropic layer O3. Moreover, an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) is applied to the surface of the optically anisotropic layer O3 of the obtained laminate, which is exposed by peeling off the cellulose acylate film T1 and the oriented film 1, to form an adhesive layer, and after the aforementioned light absorbing anisotropic layer laminate TP4 is bonded in a manner such that the adhesive layer and the oxygen barrier layer B1 are in close contact, the cellulose acylate film T1 of the light absorbing anisotropic layer laminate TP4 is peeled off, thereby obtaining the polarizer E5 of Example 5.

[0434] Polarizer E5 is a laminated body formed by sequentially stacking a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O1, an adhesive layer, a light absorption anisotropic layer P2, an adhesive layer, an optical anisotropic layer O3, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P4. Polarizer E5 is an example of polarizer 6 of the sixth embodiment. The light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O1 is equivalent to the first phase difference layer R1, the light absorption anisotropic layer P2 is equivalent to the second light absorption anisotropic layer POL2, the optical anisotropic layer O3 is equivalent to the second phase difference layer R2, and the light absorption anisotropic layer P4 is equivalent to the third light absorption anisotropic layer POL3 (see Table 2).

[0435] In addition, the in-plane phase difference Re of the optical anisotropic layer O1 at the absorption maximum wavelength (corresponding to the first wavelength λ1) of 960 nm of the optical absorption anisotropic layer P1 is 244 nm, and the in-plane phase difference Re of the optical anisotropic layer P2 is 249 nm, and the in-plane phase difference Re of the optical anisotropic layer O3 at the absorption maximum wavelength (corresponding to the second wavelength λ2) of 850 nm of the optical absorption anisotropic layer P2 is 542 nm, and the in-plane phase difference Re of the optical anisotropic layer P4 is 540 nm. That is, the phase difference ReR1(λ1)=244 nm generated in the light of the first wavelength λ1 transmitted through the first phase difference layer R1 is equivalent to the phase difference ReP2(λ1)=249 nm generated in the light of the first wavelength λ1 transmitted through the second optical absorption anisotropic layer POL2, and the formula E1 is satisfied. Furthermore, the phase difference ReR2(λ2)=542nm generated in the light of the second wavelength λ2 passing through the second phase difference layer R2 is equivalent to the phase difference ReP3(λ2)=540nm generated in the light of the second wavelength λ2 passing through the third light absorption anisotropic layer POL3, and satisfies formula E5.

[0436] In the polarizing plate E5, the directions of the absorption axis of each light absorption anisotropic layer and the slow axis of each optical anisotropic layer are as shown in Table 2 below.

[0437] {Production of optically anisotropic layer laminate TO3}

[0438] An alignment film 1 described below was formed on a cellulose acylate film T1, and an optically anisotropic layer O3 described later was formed on the alignment film 1 to produce an optically anisotropic layer laminate TO3.

[0439] (Formation of Optically Anisotropic Layer O3)

[0440] An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer B of a laminate TB including an optically anisotropic layer B described later to form an adhesive layer, and a laminate TA including an optically anisotropic layer A described later was laminated in such a manner that the adhesive layer and the optically anisotropic layer A were closely attached, and then the cellulose acylate film T1 and the oriented film 1 of the laminate TA were peeled off. An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the laminate obtained from which the cellulose acylate film T1 and the oriented film 1 were peeled off to form an adhesive layer. Another laminate TA was laminated in such a manner that the adhesive layer and the optically anisotropic layer A were closely attached. Thus, an optically anisotropic layer O3 formed by laminating the optically anisotropic layer B, the optically anisotropic layer A, and the optically anisotropic layer A was formed. When the optically anisotropic layers were bonded together, the optically anisotropic layer B, the optically anisotropic layer A, and the slow axis of the optically anisotropic layer A were oriented at 0°.

[0441] Then, the cellulose acylate film T1 and the oriented film 1 were peeled off from the laminated body TA which was finally laminated, and an optically anisotropic layer laminated body TO3 in which the oriented film 1 and the optically anisotropic layer O3 were laminated on the cellulose acylate film T1 was obtained.

[0442] -Preparation of a laminate TA including an optically anisotropic layer A-

[0443] The optically anisotropic layer A was formed by the same method as the optically anisotropic layer O1 except that the coating thickness was changed. Thus, a laminate TA in which the oriented film 1 and the optically anisotropic layer A were laminated on the cellulose acylate film T1 was obtained. In addition, two laminates TA were prepared. The thickness of the optically anisotropic layer A was 2.0 μm. The in-plane phase difference Re and the thickness direction phase difference Rth of the obtained optically anisotropic layer A at a wavelength of 550 nm were 238 nm and -119 nm, respectively.

[0444] -Preparation of laminated body TB including optically anisotropic layer B-

[0445] The composition for forming an optically anisotropic layer B of the following composition was continuously coated on the rubbing-treated oriented film 1 using a #2.8 wire rod. The conveying speed (V) of the film was set to 26 m / min. In order to dry the solvent and mature the orientation of the rod-shaped liquid crystal compound, the coating on the oriented film 1 was heated with warm air at 60°C for 60 seconds and UV irradiated at 60°C to fix the orientation of the liquid crystal compound, thereby forming an optically anisotropic layer B. Thus, a laminate TB in which the oriented film 1 and the optically anisotropic layer B were laminated on the cellulose acylate film T1 was obtained. The thickness of the optically anisotropic layer B was 1.0 μm. The average tilt angle of the major axis of the rod-shaped liquid crystal compound relative to the film surface was 0°, and it was confirmed that the liquid crystal compound was horizontally oriented relative to the film surface. The slow axis angle was orthogonal to the rotation axis of the rubbing roller, and was -77.5° when the film width direction was set to 0° (the film length direction was set to 90°, and the clockwise direction was indicated by a positive value when observed from the optically anisotropic layer B side and based on the film width direction). The in-plane phase difference Re of the optically anisotropic layer B at a wavelength of 550 nm was 116 nm.

[0446] [Composition of the composition for forming the optically anisotropic layer B]

[0447]

[0448]

[0449] Mixture of rod-like liquid crystal compounds (A)

[0450] [Chemical formula 27]

[0451]

[0452] Fluorinated compounds (F-1)

[0453] [Chemical formula 28]

[0454]

[0455] Fluorinated compounds (F-2)

[0456] [Chemical formula 29]

[0457]

[0458] <Example 6 to Example 11>

[0459] By imitating the method for preparing polarizers E1 to E5 of Examples 1 to 5, in addition to using the light absorption anisotropic layer stacks TP1 to TP4, stack TA and optical anisotropic layer stacks TO1 to TO3 prepared in Examples 1 to 5, the light absorption anisotropic layer stacks TP5 to TP9 and optical anisotropic layer stacks TO4 to TO7 described later were used to prepare polarizers E6 to E11 having the layer structures shown in Tables 2 to 5.

[0460] "Example 6"

[0461] The polarizer E6 of Example 6 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P5, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O5, an adhesive layer, a light absorption anisotropic layer P1, an adhesive layer, an optical anisotropic layer O4, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P4. The polarizer E6 is an example of the polarizer 7 of the seventh embodiment. The light absorption anisotropic layer P5 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O5 is equivalent to the first phase difference layer R1, the light absorption anisotropic layer P1 is equivalent to the second light absorption anisotropic layer POL2, the optical anisotropic layer O4 is equivalent to the second phase difference layer R2, and the light absorption anisotropic layer P4 is equivalent to the third light absorption anisotropic layer POL3 (see Table 2).

[0462] "Example 7"

[0463] The polarizer E7 of Example 7 is a laminated body formed by sequentially stacking a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O5, an adhesive layer, an oxygen barrier layer B1, a light absorption anisotropic layer P7, an adhesive layer, an optical anisotropic layer A, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P8. The polarizer E7 is an example of the polarizer 6 of the sixth embodiment. The light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O5 is equivalent to the first phase difference layer R1, the light absorption anisotropic layer P7 is equivalent to the second light absorption anisotropic layer POL2, the optical anisotropic layer A is equivalent to the second phase difference layer R2, and the light absorption anisotropic layer P8 is equivalent to the third light absorption anisotropic layer POL3 (refer to Table 2).

[0464] "Example 8"

[0465] The polarizer E8 of Example 8 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O1, an adhesive layer, a light absorption anisotropic layer P2, an adhesive layer, an optical anisotropic layer O6, an adhesive layer, and a light absorption anisotropic layer P6. The polarizer E8 is an example of the polarizer 6 of the sixth embodiment. The light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O1 is equivalent to the first phase difference layer R1, the light absorption anisotropic layer P2 is equivalent to the second light absorption anisotropic layer POL2, the optical anisotropic layer O6 is equivalent to the second phase difference layer R2, and the light absorption anisotropic layer P6 is equivalent to the third light absorption anisotropic layer POL3 (see Table 2).

[0466] "Example 9"

[0467] The polarizer E9 of Example 9 is a laminated body formed by sequentially stacking a light absorption anisotropic layer P1, a cellulose acylate film T1, an adhesive layer, an optical anisotropic layer O7, an adhesive layer, an oxygen barrier layer B1 and a light absorption anisotropic layer P4. The polarizer E9 has a structure similar to that of the polarizer 2 of the second embodiment. The light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O7 is equivalent to the first phase difference layer R1, and the light absorption anisotropic layer P4 is equivalent to the second light absorption anisotropic layer POL2 (refer to Table 2). However, as shown in Table 2, the in-plane phase difference ReR1 (λ1) of the first phase difference layer R1 and the in-plane phase difference ReP2 (λ1) of the second light absorption anisotropic layer POL2 at the first wavelength λ1 (here 960nm) of the first light absorption anisotropic layer POL1 do not satisfy Formula E1.

[0468] "Example 10"

[0469] The polarizer E10 of Example 10 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P6, a cellulose acylate film T1, an adhesive layer, a light absorption anisotropic layer P1, an adhesive layer, an optical anisotropic layer O4, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P4. The polarizer E10 is an example of the polarizer 5 of the fifth embodiment. The light absorption anisotropic layer P6 is equivalent to the third light absorption anisotropic layer POL3, the light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, the optical anisotropic layer O4 is equivalent to the first phase difference layer R1, and the light absorption anisotropic layer P4 is equivalent to the second light absorption anisotropic layer POL2 (see Table 3).

[0470] "Example 11"

[0471] The polarizer E11 of Example 11 is a laminated body formed by sequentially laminating a light absorption anisotropic layer P9, a cellulose acylate film T1, an adhesive layer, a light absorption anisotropic layer P1, an adhesive layer, an oxygen barrier layer B1, and a light absorption anisotropic layer P4. The polarizer E11 is an example of the polarizer 4 of the fourth embodiment. The light absorption anisotropic layer P9 is equivalent to the third light absorption anisotropic layer POL3, the light absorption anisotropic layer P1 is equivalent to the first light absorption anisotropic layer POL1, and the light absorption anisotropic layer P4 is equivalent to the second light absorption anisotropic layer POL2. The absorption maximum wavelength of the light absorption anisotropic layer P9 is equivalent to the third wavelength λ3, the absorption maximum wavelength of the light absorption anisotropic layer P1 is equivalent to the first wavelength λ1, and the absorption maximum wavelength of the light absorption anisotropic layer P4 is equivalent to the second wavelength λ2 (refer to Table 4).

[0472] {Production of light-absorbing anisotropic layer stack TP5}

[0473] In the preparation of the light absorption anisotropic layer laminate TP1, a light absorption anisotropic layer laminate TP5 in which the light absorption anisotropic layer P5 was laminated on the cellulose acylate film T1 was prepared in the same manner except that the light absorption anisotropic layer P1 was changed to a light absorption anisotropic layer P5 described later.

[0474] (Formation of Light Absorption Anisotropic Layer P5)

[0475] A light absorption anisotropic layer P5 was prepared on one side of the cellulose acylate film T1 by the same method as the light absorption anisotropic layer P1 except that the dichroic dye II-2 was replaced with the aforementioned dichroic dye II-3. The absorption maximum wavelength of the light absorption anisotropic layer P5 was 1050 nm.

[0476] {Production of light-absorbing anisotropic layer laminate TP6}

[0477] In the preparation of the light absorption anisotropic layer laminate TP1, a light absorption anisotropic layer laminate TP6 in which the light absorption anisotropic layer P6 was laminated on the cellulose acylate film T1 was prepared in the same manner except that the light absorption anisotropic layer P1 was changed to a light absorption anisotropic layer P6 described later.

[0478] (Formation of Light Absorption Anisotropic Layer P6)

[0479] The light absorption anisotropic layer P6 was formed by the same method as the light absorption anisotropic layer P1 except that the dichroic dye II-2 was replaced with the above-mentioned dichroic dye II-4. The absorption maximum wavelength of the light absorption anisotropic layer P6 was 1160 nm.

[0480] {Production of light-absorbing anisotropic layer laminate TP7}

[0481] In the preparation of the light absorption anisotropic layer stack TP4, the light absorption anisotropic layer P4 is changed to the light absorption anisotropic layer P7 described later. In addition, the light absorption anisotropic layer stack TP7 composed of stacked cellulose acylate film T2, photo-alignment film PA1, light absorption anisotropic layer P7 and oxygen barrier layer B1 is prepared in the same manner.

[0482] (Formation of Light Absorption Anisotropic Layer P7)

[0483] The light absorption anisotropic layer P7 was formed by the same method as the light absorption anisotropic layer P1 except that the dichroic dye II-2 was replaced with the above-mentioned dichroic dye Y-1. The absorption maximum wavelength of the light absorption anisotropic layer P7 was 417 nm.

[0484] {Production of light-absorbing anisotropic layer stack TP8}

[0485] In the preparation of the light absorption anisotropic layer stack TP4, the light absorption anisotropic layer P4 is changed to the light absorption anisotropic layer P8 described later. In addition, the light absorption anisotropic layer stack TP8 composed of stacked cellulose acylate film T2, photo-alignment film PA1, light absorption anisotropic layer P8 and oxygen barrier layer B1 is prepared in the same manner.

[0486] (Formation of Light Absorption Anisotropic Layer P8)

[0487] The light absorption anisotropic layer P8 was formed by the same method as the light absorption anisotropic layer P1 except that the dichroic dye II-2 was replaced with the above-mentioned dichroic dye C-1. The absorption maximum wavelength of the light absorption anisotropic layer P8 was 570 nm.

[0488] {Production of light-absorbing anisotropic layer stack TP9}

[0489] In the production of the light absorption anisotropic layer stack TP1, a light absorption anisotropic layer stack TP9 was produced by the same method except that the light absorption anisotropic layer P1 was changed to a light absorption anisotropic layer P9 described later.

[0490] (Formation of Light Absorption Anisotropic Layer P9)

[0491] The light absorption anisotropic layer P9 was formed by the same method as the light absorption anisotropic layer P1 except that the dichroic dye II-2 was replaced with the above-mentioned dichroic dye II-5. The absorption maximum wavelength of the light absorption anisotropic layer P9 was 740 nm.

[0492] {Production of optically anisotropic layer laminate TO4}

[0493] The alignment film 1 is formed on the cellulose acylate film T1 through the above-described steps, and the optically anisotropic layer O4 is formed on the alignment film 1 to obtain the optically anisotropic layer laminate TO4.

[0494] (Formation of Optically Anisotropic Layer O4)

[0495] An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer O1 of the optically anisotropic layer laminate TO1 to form an adhesive layer, and the laminate TA was laminated in such a manner that the adhesive layer and the optically anisotropic layer A were closely attached. Then, the cellulose acylate film T1 and the oriented film 1 of the laminate TA were peeled off to obtain an optically anisotropic layer O4. The optically anisotropic layer O4 was parallel to the slow axis of the optically anisotropic layer A. The in-plane phase difference Re of the obtained optically anisotropic layer O4 at a wavelength of 850 nm was 462 nm.

[0496] {Production of optically anisotropic layer laminate TO5}

[0497] The alignment film 1 is formed on the cellulose acylate film T1 through the above-described steps, and the optically anisotropic layer O5 is formed on the alignment film 1 to obtain an optically anisotropic layer laminate TO5.

[0498] (Formation of Optically Anisotropic Layer O5)

[0499] An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer A of the aforementioned laminate TA to form an adhesive layer, and another laminate TA was laminated in such a way that the adhesive layer and the optically anisotropic layer A were closely attached. Thus, an optically anisotropic layer O5 formed by laminating two layers of optically anisotropic layers A via an adhesive layer was formed. Then, the cellulose acylate film T1 and the oriented film 1 were peeled off to form an optically anisotropic layer laminate TO5. In addition, the slow axis of the optically anisotropic layer A was oriented parallel. The Re of the obtained optically anisotropic layer O5 at a wavelength of 960 nm was 435 nm.

[0500] {Production of optically anisotropic layer laminate TO6}

[0501] The alignment film 1 was formed on the cellulose acylate film T1 by the above-described steps, and the optically anisotropic layer O6 described later was formed on the alignment film 1 to produce an optically anisotropic layer laminate TO6.

[0502] (Formation of Optically Anisotropic Layer O6)

[0503] The optically anisotropic layer O6 was formed on the oriented film 1 formed on the cellulose acylate film T1 by the same method as that of the optically anisotropic layer B except that the coating thickness was changed. The obtained optically anisotropic layer O6 had a Re of 150 nm at a wavelength of 850 nm.

[0504] Thus, an optically anisotropic layer laminate TO6 in which the oriented film 1 and the optically anisotropic layer O6 were laminated in this order on the cellulose acylate film T1 was obtained.

[0505] {Production of optically anisotropic layer laminate TO7}

[0506] The alignment film 1 was formed on the cellulose acylate film T1 by the above-described steps, and the optically anisotropic layer O7 described later was formed on the alignment film 1 to produce an optically anisotropic layer laminate TO7.

[0507] (Formation of Optically Anisotropic Layer O7)

[0508] An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer O1 of the optically anisotropic layer laminate TO1 to form an adhesive layer, and the laminate TB including the optically anisotropic layer B was laminated in such a manner that the adhesive layer and the optically anisotropic layer B were closely attached. Thus, an optically anisotropic layer O7 formed by laminating the optically anisotropic layer O1 and the optically anisotropic layer B was formed. In addition, when laminating the optically anisotropic layer B, the slow axis of the optically anisotropic layer O1 was parallel to the slow axis of the optically anisotropic layer B. The Re of the obtained optically anisotropic layer O7 at a wavelength of 960 nm was 347 nm.

[0509] Then, the cellulose acylate film T1 and the oriented film 1 were peeled off to obtain an optically anisotropic layer laminate TO7 in which the oriented film 1 and the optically anisotropic layer O7 were laminated on the cellulose acylate film T1.

[0510] <Example 12>

[0511] "Production of Polarizer E12"

[0512] An adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to one side of a wavelength selective polarization conversion element (Color Select-BY:BY Filter manufactured by ColorLink Japan, Ltd.) to form an adhesive layer, and the aforementioned light absorption anisotropic layer laminate TP 4 was laminated in such a manner that the adhesive layer and the oxygen barrier layer B1 were closely attached, and then the cellulose acylate film T2 and the photo-alignment film PA1 were peeled off. Next, an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the other side of the aforementioned wavelength selective polarization conversion element to form an adhesive layer, and the optical anisotropic layer laminate TO8 described later was laminated in such a manner that the adhesive layer and the optical anisotropic layer O8 were closely attached, and then the cellulose acylate film T1 and the alignment film 1 of the optical anisotropic layer laminate TO8 were peeled off. Furthermore, an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was applied to the surface of the optically anisotropic layer O8 of the obtained laminate, which was exposed by peeling off the cellulose acylate film T1 and the oriented film 1, to form an adhesive layer. Then, the light absorbing anisotropic layer laminate TP1 was laminated in such a manner that the adhesive layer and the light absorbing anisotropic layer P1 were closely attached, and then the cellulose acylate film of the light absorbing anisotropic layer laminate TP1 was peeled off, thereby obtaining a polarizing plate E12 of Example 12. In addition, the absorption axis of each light absorbing anisotropic layer and the slow axis of each optically anisotropic layer are shown in Table 5.

[0513] Polarizer E12 is a laminated body formed by sequentially stacking a light absorption anisotropic layer P4, an oxygen barrier layer B1, an adhesive layer, a wavelength selective polarization conversion element, an adhesive layer, an optical anisotropic layer O8, an adhesive layer and a light absorption anisotropic layer P1. Polarizer E12 is an example of polarizer 8 of the eighth embodiment, the light absorption anisotropic layer P4 is equivalent to the first light absorption anisotropic layer POL1, the wavelength selective polarization conversion element is equivalent to the third phase difference layer R3, the optical anisotropic layer O8 is equivalent to the fourth phase difference layer R4, and the light absorption anisotropic layer P1 is equivalent to the second light absorption anisotropic layer POL2. The light absorption anisotropic layer P4 shows light absorption anisotropy throughout the entire visible light region. At this time, in the light absorption anisotropic layer P4, any wavelength in the visible light region can be set to the first wavelength λ1 and the fourth wavelength λ4. In this example, the fourth wavelength λ4 is set to 550nm.

[0514] {Production of optically anisotropic layer laminate TO8}

[0515] An alignment film 1 was formed on a cellulose acylate film T1, and an optically anisotropic layer O8 was formed on the alignment film 1 to produce an optically anisotropic layer laminate TO8.

[0516] (Formation of Optically Anisotropic Layer O8)

[0517] The optically anisotropic layer O8 was formed on the oriented film 1 formed on the cellulose acylate film T1 by the same composition and the same method as the optically anisotropic layer B except that the coating thickness was changed. The obtained optically anisotropic layer O8 had an in-plane retardation ReR4 (550) of 200 nm at a wavelength of 550 nm.

[0518] <Comparative Example>

[0519] "Production of Polarizing Plate C1"

[0520] In the preparation of the polarizing plate E1 of Example 1, when the light absorption anisotropic layer P2 was bonded to the adhesive layer formed on the surface of the light absorption anisotropic layer P1, the angle formed by the absorption axis of the light absorption anisotropic layer P1 and the absorption axis of the light absorption anisotropic layer P2 was made to be 0°. Except for this, the polarizing plate C1 of Comparative Example 1 was prepared by the same method as Example 1.

[0521] Table 1 shows the dichroic dyes and absorption maximum wavelengths contained in the light absorption anisotropic layers P1 to P9 .

[0522] [Table 1]

[0523]

[0524] In addition, as described above, the light absorption anisotropic layer P4 includes three dichroic pigments. In Table 1, the absorption maximum wavelengths of the three dichroic pigments are shown. The light absorption anisotropic layer P4 represents an absorption spectrum obtained by adding the absorption spectra of the three dichroic pigments, and shows a roughly uniform high absorbance throughout the visible light region of 400nm to 700nm. Therefore, for the light absorption anisotropic layer P4, it is possible to set an arbitrary wavelength to be extracted as linear polarized light of a specific polarization direction from the wavelength range of 400nm to 700nm as the absorption wavelength as the absorption maximum wavelength.

[0525] Table 2 summarizes the structures of the polarizing plates of Examples 1 to 9 and Comparative Example 1. In Table 2, the first light absorption anisotropic layer (first light absorption anisotropic layer POL1), the first phase difference layer (first phase difference layer R1), the second light absorption anisotropic layer (second light absorption anisotropic layer POL2), the second phase difference layer (second phase difference layer R2), and the third light absorption anisotropic layer (third light absorption anisotropic layer POL3) are sequentially recorded from the light incident side. In addition, in Table 2, only the layers that affect polarized light are recorded, and the adhesive layer and the oxygen barrier layer B1 are omitted. The same is true in Tables 3 to 5.

[0526]

[0527] Table 3 shows the structure of the polarizing plate of Example 10.

[0528] [Table 3]

[0529]

[0530] Table 4 shows the structure of the polarizing plate of Example 11.

[0531] [Table 4]

[0532]

[0533] Table 5 shows the structure of the polarizing plate of Example 12.

[0534] [Table 5]

[0535]

[0536] The in-plane phase difference of the light absorption anisotropic layer and the optical anisotropic layer was determined by measuring and analyzing the wavelength region of 246 to 1698 nm using a spectroscopic ellipsometer (manufactured by JA Woollam).

[0537] <Evaluation>

[0538] The polarizing plates of Examples and Comparative Examples were evaluated as follows.

[0539] [Optical properties]

[0540] The transmittance of each polarizer E1 to E12 and C1 to non-polarized light (single transmittance) was measured by UV-3600 (manufactured by SHIMADZU CORPORATION) using an ultraviolet-visible-near-infrared spectrophotometer. The measured transmittance was averaged within the wavelength range of 400 to 700 nm, and the transmittance to visible light (visible light transmittance) was evaluated according to the following criteria.

[0541] A: The average transmittance at wavelengths of 400 to 700 nm is 50% or more

[0542] B: The average transmittance at wavelengths of 400 to 700 nm is less than 50%

[0543] The polarizing plate having any one of the light absorption anisotropic layers P4, P7, and P8 having an absorption maximum wavelength in the visible light region was evaluated as B, while the polarizing plate having only the light absorption anisotropic layer having an absorption maximum wavelength in the near infrared light region was evaluated as A. In this way, by measuring the average of the single transmittance in the visible light region of wavelengths 400 nm to 700 nm, it can be confirmed that the absorption maximum wavelength of the light absorption anisotropic layer included in the polarizing plate is not in the visible light region.

[0544] [Discrimination]

[0545] The polarizing plates of the respective examples and comparative examples were evaluated for discrimination. Fig.17 , the evaluation method related to the polarizing plate E1 of Example 1 is described as an example.

[0546] A solution obtained by dissolving 0.05 parts by mass of an absorption pigment FDN-007 (YAMADA CHEMICAL CO., LTD.) having an absorption maximum wavelength at 956 nm in 95.5 parts by mass of toluene and a solution obtained by dissolving 0.05 parts by mass of an absorption pigment FDN-003 (YAMADA CHEMICAL CO., LTD.) having an absorption maximum wavelength at 853 nm in 95.5 parts by mass of toluene were respectively cast on a glass 70 without overlapping each other and dried naturally to form evaluation images G1 and G2. The glass 70 on which the evaluation images G1 and G2 were formed, the polarizing plate E1, and the commercially available wire grid polarizing plate (MLP-WG) 72 were sequentially overlapped, and the evaluation images G1 and G2 were observed from the wire grid polarizing plate 72 side using a CMOS camera 76. The evaluation image G1 absorbs the first wavelength λ1 of the polarizing plate E1, and the evaluation image G2 absorbs the second wavelength λ2.

[0547] The wire grid polarizer 72 was rotated to change the angle formed by the absorption axis of the wire grid polarizer 72 and the absorption axis of the first light absorption anisotropic layer disposed on the light incident side of the polarizer E1. At this time, the angle formed by the two absorption axes when the evaluation images G1 and G2 were best visually recognized was investigated. The results are shown in Table 6 as "best visually recognized angle".

[0548] In the case of the polarizing plate E1 of Example 1, if the wire grid polarizing plate 72 is rotated, the evaluation image G1 is best visually recognized when the angle of the absorption axis of the wire grid polarizing plate 72 is 0°, and the evaluation image G2 is best visually recognized when the absorption axis angle is 90°. Here, the absorption axis angle of the wire grid polarizing plate 72 is the angle formed by the absorption axis of the wire grid polarizing plate 72 and the absorption axis of the first light absorption anisotropic layer of the polarizing plate E1. The evaluation image G1 and the evaluation image G2 can be distinguished from each other based on the change in light intensity visually recognized when the wire grid polarizing plate 72 is rotated. The evaluation image G1 is an image of light of the first wavelength λ1 of the polarizing plate E1, and the evaluation image G2 is an image of light of the second wavelength λ2 of the polarizing plate E1. If the optimal visual recognition angles of the evaluation image G1 and the evaluation image G2 are different when the wire grid polarizer 72 is rotated, and the two evaluation images G1 and G2 can be distinguished, it means that the light of the first wavelength λ1 and the light of the second wavelength λ2 are transmitted through the polarizer E1 as linear polarized lights with different polarization directions.

[0549] The same method was used to evaluate the discriminability of the polarizers of each embodiment and comparative example. Evaluation images G1, G2 and G3 corresponding to the first wavelength λ1, the second wavelength λ2 and the third wavelength λ3 in each polarizer were prepared and evaluated. The absorption pigments used in the evaluation images G1, G2 and G3 in each embodiment and comparative example are shown in Table 6 below. In addition, regarding the absorption pigment, 400-500nm absorption pigment (FDB series), 500-750nm absorption pigment (FDG series) and 750-1000nm absorption pigment (FDN series) of YAMA DA CHEMICAL CO., LTD. were used, and as for the solvent, toluene was used, or when it was not soluble in toluene, methyl ethyl ketone was used.

[0550] The discrimination was evaluated as a sensory evaluation according to the following criteria: A: The evaluation image can be clearly distinguished by the change in light intensity caused by the rotation of the polarizing plate.

[0551] B: The evaluation images can be roughly distinguished based on the change in light intensity caused by the rotation of the polarizer.

[0552] C: The evaluation image can be slightly distinguished by the change in light intensity caused by the rotation of the polarizing plate.

[0553] D: The evaluation image cannot be distinguished by the change in light intensity caused by the rotation of the polarizing plate.

[0554] Table 6 summarizes the discriminability evaluation images, the discriminability evaluation results, and the visible light transmittance evaluation results.

[0555]

[0556] As shown in Table 6, the polarizing plates E1 to E12 of the examples of the present invention showed excellent discrimination properties. On the other hand, the polarizing plate C1 of the comparative example did not achieve the desired effect.

[0557] Regarding the above embodiment, the following additional notes are also disclosed.

[0558] (Note 1)

[0559] A polarizing plate, comprising:

[0560] a first light absorption anisotropic layer including a first dichroic dye and having a first light absorption characteristic in which the absorbance reaches a maximum at a first wavelength and having a first absorption axis along one direction showing the first light absorption characteristic; and

[0561] a second light absorption anisotropic layer comprising a second dichroic pigment and having a second light absorption characteristic in which the absorbance reaches a maximum at a second wavelength different from the first wavelength, and having a second absorption axis along one direction showing the second light absorption characteristic,

[0562] The first light absorption anisotropic layer and the second light absorption anisotropic layer are stacked such that the first absorption axis intersects with the second absorption axis.

[0563] (Note 2)

[0564] The polarizing plate according to Supplementary Note 1, wherein

[0565] At least one of the first wavelength and the second wavelength is within a range of 700 nm to 1500 nm.

[0566] (Note 3)

[0567] The polarizing plate according to Supplement 1 or Supplement 2, wherein

[0568] Both the first wavelength and the second wavelength are within a range of 700 nm to 1500 nm.

[0569] (Note 4)

[0570] The polarizing plate according to any one of Supplementary Notes 1 to 3, wherein

[0571] An absolute value of a difference between the first wavelength showing a local maximum in the first absorption spectrum of the first light absorption anisotropic layer and the second wavelength showing a local maximum in the second absorption spectrum of the second light absorption anisotropic layer is larger than an average value of a half width at half maximum of the first absorption spectrum and a half width at half maximum of the second absorption spectrum.

[0572] (Note 5)

[0573] The polarizing plate according to any one of Supplementary Notes 1 to 4, wherein

[0574] The average single-body transmittance in the wavelength range of 400 nm to less than 700 nm is 50% or more.

[0575] (Note 6)

[0576] The polarizing plate according to any one of Supplementary Notes 1 to 5, wherein

[0577] The first absorption axis is orthogonal to the second absorption axis, and no phase difference layer for imparting a phase difference to transmitted light is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer.

[0578] (Note 7)

[0579] The polarizing plate according to any one of Supplementary Notes 1 to 5, wherein

[0580] The first absorption axis is not orthogonal to the second absorption axis.

[0581] A first phase difference layer is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer, the first phase difference layer is a phase difference layer that provides a phase difference to the transmitted light, and when the first wavelength is set to λ1, the phase difference generated in the light of the first wavelength λ1 that transmits the second light absorption anisotropic layer is set to ReP2(λ1), and the phase difference generated in the light of the first wavelength λ1 that transmits the phase difference layer is set to ReR1(λ1), the following formula E1 is satisfied:

[0582] The first retardation layer is disposed such that a first slow axis, which is a slow axis of the first retardation layer, is orthogonal to the second absorption axis.

[0583] ReP2(λ1) / ReR1(λ1)=1±0.2Formula E1

[0584] (Note 8)

[0585] The polarizing plate according to any one of Supplementary Notes 1 to 5, wherein

[0586] The first absorption axis is not orthogonal to the second absorption axis.

[0587] When the first wavelength is λ1 and the phase difference generated in the light of the first wavelength λ1 that transmits the second light absorption anisotropic layer is ReP2(λ1), the following formula E2-1 or E2-2 is satisfied.

[0588] ReP2(λ1) / λ1=1±0.2Formula E2-1

[0589] ReP2(λ1) / λ1=0.5±0.1 Formula E2-2

[0590] (Note 9)

[0591] The polarizing plate according to any one of Supplementary Notes 1 to 8, further comprising a third light absorption anisotropic layer, wherein the third light absorption anisotropic layer contains a third dichroic pigment and has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength different from the first wavelength and the second wavelength, and has a third absorption axis along one direction showing the first light absorption characteristic,

[0592] The third light absorption anisotropic layer is arranged so that the third absorption axis intersects with at least one of the first absorption axis and the second absorption axis.

[0593] (Note 10)

[0594] The polarizing plate according to Supplement 9 referring to Supplement 7, wherein

[0595] The third light absorption anisotropic layer, the first light absorption anisotropic layer, and the second light absorption anisotropic layer are stacked in this order from the incident direction of light,

[0596] The first absorption axis is parallel to the third absorption axis.

[0597] When the third wavelength is set to λ3 and the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer is set to ReP2(λ3), the two equations E2-1 and the following equation E3-1 are satisfied, or the two equations E2-2 and the following equation E3-2 are satisfied.

[0598] ReP2(λ3) / λ3=0.5±0.1 Formula E3-1

[0599] ReP2(λ3) / λ3=1±0.2Formula E3-2

[0600] (Note 11)

[0601] The polarizing plate according to Supplement 9 referring to Supplement 7, wherein

[0602] The third light absorption anisotropic layer, the first light absorption anisotropic layer, the first retardation layer, and the second light absorption anisotropic layer are stacked in this order from the incident direction of light,

[0603] The first absorption axis is orthogonal to the third absorption axis.

[0604] When the third wavelength is set to λ3, the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer is set to ReP2(λ3), and the phase difference generated in the light of the third wavelength λ3 passing through the first phase difference layer is set to ReR1(λ3), the following formula E4 is satisfied.

[0605] ReP2(λ3) / ReR1(λ3)=1±0.2 E4

[0606] (Note 12)

[0607] The polarizing plate according to Supplement 9 referring to Supplement 7, wherein

[0608] The first light absorption anisotropic layer, the first retardation layer, the second light absorption anisotropic layer, and the third light absorption anisotropic layer are stacked in this order from the incident direction of light,

[0609] The third light absorption anisotropic layer is arranged so that the third absorption axis intersects with the first absorption axis and the second absorption axis.

[0610] A second retardation layer for imparting a phase difference to the transmitted light is further provided between the second light absorption anisotropic layer and the third light absorption anisotropic layer.

[0611] When the phase difference generated in the light of the second wavelength λ2 passing through the third light absorption anisotropic layer is set to ReP3(λ2), and the phase difference generated in the light of the second wavelength λ2 passing through the second phase difference layer is set to ReR2(λ2), the second phase difference layer satisfies the following formula E5,

[0612] The second retardation layer is arranged such that a second slow axis, which is a slow axis of the second retardation layer, is orthogonal to the third absorption axis.

[0613] ReP3(λ2) / ReR2(λ2)=1±0.2Formula E5

[0614] (Note 13)

[0615] The polarizing plate according to Supplementary Note 12, wherein

[0616] The first absorption axis and the third absorption axis intersect but are not orthogonal to each other.

[0617] When the phase difference generated in the light of the first wavelength λ1 passing through the third light absorption anisotropic layer is set to ReP3(λ1), and the phase difference generated in the light of the first wavelength λ1 passing through the second phase difference layer is set to ReR2(λ1), the second phase difference layer satisfies the following formula E6.

[0618] ReP3(λ1) / ReR2(λ1)=1±0.2 E6

[0619] The polarizing plate according to any one of Supplementary Notes 1 to 5, wherein

[0620] The first light absorption anisotropic layer includes a fourth dichroic pigment in addition to the first dichroic pigment, and exhibits a fourth light absorption characteristic in which absorbance reaches a maximum at a fourth wavelength different from the first wavelength and the second wavelength, and the first absorption axis is an absorption axis that exhibits the fourth light absorption characteristic in addition to the first light absorption characteristic.

[0621] The first light absorption anisotropic layer, the third phase difference layer, the fourth phase difference layer, and the second light absorption anisotropic layer are stacked in this order from the incident direction of light,

[0622] The third phase difference layer is a phase difference layer that selectively provides a phase difference that changes the polarization direction of light of one of the first wavelength and the fourth wavelength output from the first light absorption anisotropic layer.

[0623] When the first wavelength is set to λ1, the fourth wavelength is set to λ4, the phase difference generated in the first wavelength λ1 transmitted through the fourth phase difference layer is set to ReR4(λ1), the phase difference generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer is set to ReP2(λ1), the phase difference generated in the fourth wavelength λ4 transmitted through the fourth phase difference layer is set to ReR4(λ4), and the phase difference generated in the light of the fourth wavelength λ4 transmitted through the second light absorption anisotropic layer is set to ReP2(λ4),

[0624] The fourth phase difference layer satisfies at least one of the following formulas E7-1 and E7-2, and

[0625] The fourth retardation layer is arranged such that a fourth slow axis, which is a slow axis of the fourth retardation layer, is orthogonal to the second absorption axis.

[0626] ReP2(λ1) / ReR4(λ1)=1±0.2 Formula E7-1

[0627] ReP2(λ4) / ReR4(λ4)=1±0.2 E7-2

[0628] In addition, all the disclosed contents of Japanese Patent Application No. 2022-122203 filed on July 29, 2022 are incorporated into this specification by reference. Furthermore, all the documents, patent applications, and technical standards described in this specification are incorporated into this specification by reference to the same extent as if each document, patent application, and technical standard were specifically and individually described as being incorporated by reference.

Claims

1. A polarizing plate, comprising: a first light absorption anisotropic layer including a first dichroic dye and having a first light absorption characteristic in which the absorbance reaches a maximum at a first wavelength and having a first absorption axis along one direction showing the first light absorption characteristic; and a second light absorption anisotropic layer comprising a second dichroic pigment and having a second light absorption characteristic in which the absorbance reaches a maximum at a second wavelength different from the first wavelength, and having a second absorption axis along one direction showing the second light absorption characteristic, The first light absorption anisotropic layer and the second light absorption anisotropic layer are stacked such that the first absorption axis intersects with the second absorption axis.

2. The polarizing plate according to claim 1, wherein At least one of the first wavelength and the second wavelength is within a range of 700 nm to 1500 nm.

3. The polarizing plate according to claim 1, wherein Both the first wavelength and the second wavelength are within a range of 700 nm to 1500 nm.

4. The polarizing plate according to claim 1, wherein An absolute value of a difference between the first wavelength showing a local maximum in the first absorption spectrum of the first light absorption anisotropic layer and the second wavelength showing a local maximum in the second absorption spectrum of the second light absorption anisotropic layer is larger than an average value of a half width at half maximum of the first absorption spectrum and a half width at half maximum of the second absorption spectrum.

5. The polarizing plate according to claim 1, wherein The average single-body transmittance in the wavelength range of 400 nm to less than 700 nm is 50% or more.

6. The polarizing plate according to claim 1, wherein The first absorption axis is orthogonal to the second absorption axis, and no phase difference layer for imparting a phase difference to transmitted light is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer.

7. The polarizing plate according to claim 1, wherein The first absorption axis is not orthogonal to the second absorption axis. A first phase difference layer is provided between the first light absorption anisotropic layer and the second light absorption anisotropic layer, the first phase difference layer is a phase difference layer that provides a phase difference to the transmitted light, and when the first wavelength is set to λ1, the phase difference generated in the light of the first wavelength λ1 that transmits the second light absorption anisotropic layer is set to ReP2(λ1), and the phase difference generated in the light of the first wavelength λ1 that transmits the phase difference layer is set to ReR1(λ1), the following formula E1 is satisfied: The first retardation layer is arranged so that a first slow axis, which is a slow axis of the first retardation layer, is orthogonal to the second absorption axis. ReP2(λ1) / ReR1(λ1)=1±0.2Formula E1.

8. The polarizing plate according to claim 1, wherein The first absorption axis is not orthogonal to the second absorption axis. When the first wavelength is λ1 and the phase difference generated in the light of the first wavelength λ1 passing through the second light absorption anisotropic layer is ReP2(λ1), the following formula E2-1 or E2-2 is satisfied: ReP2(λ1) / λ1=1±0.2 Formula E2-1, ReP2(λ1) / λ1=0.5±0.1 Formula E2-2.

9. The polarizing plate according to any one of claims 1 to 8, wherein The invention further comprises a third light absorption anisotropic layer, wherein the third light absorption anisotropic layer contains a third dichroic pigment and has a third light absorption characteristic in which the absorbance reaches a maximum at a third wavelength different from the first wavelength and the second wavelength, and has a third absorption axis along one direction showing the first light absorption characteristic. The third light absorption anisotropic layer is arranged so that the third absorption axis intersects with at least one of the first absorption axis and the second absorption axis.

10. The polarizing plate according to claim 9 as referred to claim 7, wherein: The third light absorption anisotropic layer, the first light absorption anisotropic layer, and the second light absorption anisotropic layer are stacked in this order from the incident direction of light, The first absorption axis is parallel to the third absorption axis. When the third wavelength is set to λ3 and the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer is set to ReP2(λ3), the two equations of the above-mentioned formula E2-1 and the following formula E3-1 are satisfied, or the two equations of the above-mentioned formula E2-2 and the following formula E3-2 are satisfied, ReP2(λ3) / λ3=0.5±0.1 Formula E3-1, ReP2(λ3) / λ3=1±0.2 Formula E3-2.

11. The polarizing plate according to claim 9 as referred to claim 7, wherein: The third light absorption anisotropic layer, the first light absorption anisotropic layer, the first retardation layer, and the second light absorption anisotropic layer are stacked in this order from the incident direction of light, The first absorption axis is orthogonal to the third absorption axis. When the third wavelength is set to λ3, the phase difference generated in the light of the third wavelength λ3 passing through the second light absorption anisotropic layer is set to ReP2(λ3), and the phase difference generated in the light of the third wavelength λ3 passing through the first phase difference layer is set to ReR1(λ3), the following formula E4 is satisfied: ReP2(λ3) / ReR1(λ3)=1±0.2 E4.

12. The polarizing plate according to claim 9 as defined in claim 7, wherein: The first light absorption anisotropic layer, the first retardation layer, the second light absorption anisotropic layer, and the third light absorption anisotropic layer are stacked in this order from the incident direction of light, The third light absorption anisotropic layer is arranged so that the third absorption axis intersects with the first absorption axis and the second absorption axis. A second retardation layer for imparting a phase difference to the transmitted light is further provided between the second light absorption anisotropic layer and the third light absorption anisotropic layer. When the phase difference generated in the light of the second wavelength λ2 passing through the third light absorption anisotropic layer is set to ReP3(λ2), and the phase difference generated in the light of the second wavelength λ2 passing through the second phase difference layer is set to ReR2(λ2), the second phase difference layer satisfies the following formula E5, The second retardation layer is arranged so that a second slow axis, which is a slow axis of the second retardation layer, is orthogonal to the third absorption axis. ReP3(λ2) / ReR2(λ2)=1±0.2Formula E5.

13. The polarizing plate according to claim 12, wherein: The first absorption axis and the third absorption axis intersect but are not orthogonal to each other. When the phase difference generated in the light of the first wavelength λ1 transmitted through the third light absorption anisotropic layer is set to ReP3(λ1), and the phase difference generated in the light of the first wavelength λ1 transmitted through the second phase difference layer is set to ReR2(λ1), the second phase difference layer satisfies the following formula E6, ReP3(λ1) / ReR2(λ1)=1±0.2 E6.

14. The polarizing plate according to any one of claims 1 to 5, wherein The first light absorption anisotropic layer includes a fourth dichroic dye in addition to the first dichroic dye, and exhibits a fourth light absorption characteristic in which absorbance reaches a maximum at a fourth wavelength different from the first wavelength and the second wavelength, and the first absorption axis is an absorption axis that exhibits the fourth light absorption characteristic in addition to the first light absorption characteristic. The first light absorption anisotropic layer, the third phase difference layer, the fourth phase difference layer and the second light absorption anisotropic layer are stacked in this order from the incident direction of light, The third phase difference layer is a phase difference layer that selectively provides a phase difference that changes the polarization direction of light of one of the first wavelength and the fourth wavelength output from the first light absorption anisotropic layer. When the first wavelength is set to λ1, the fourth wavelength is set to λ4, the phase difference generated in the first wavelength λ1 transmitted through the fourth phase difference layer is set to ReR4(λ1), the phase difference generated in the light of the first wavelength λ1 transmitted through the second light absorption anisotropic layer is set to ReP2(λ1), the phase difference generated in the fourth wavelength λ4 transmitted through the fourth phase difference layer is set to ReR4(λ4), and the phase difference generated in the light of the fourth wavelength λ4 transmitted through the second light absorption anisotropic layer is set to ReP2(λ4), The fourth phase difference layer satisfies at least one of the following formulas E7-1 and E7-2, and The fourth phase difference layer is arranged so that a fourth slow axis, which is a slow axis of the fourth phase difference layer, is orthogonal to the second absorption axis. ReP2(λ1) / ReR4(λ1)=1±0.2 Formula E7-1, ReP2(λ4) / ReR4(λ4)=1±0.2 Formula E7-2.

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