Viewing angle control system and image display device

Abstract

The invention provides a viewing angle control system and an image display device which can realize high brightness in the front direction and low brightness in the inclined direction of a specific azimuth angle when applied to a light source. This viewing angle control system (100A) has a first polarizer (10), a first optical compensation layer (12), a first liquid crystal cell (14), a second polarizer (16), a second liquid crystal cell (18), a second optical compensation layer (20), and a third polarizer (22) in this order, and the first liquid crystal cell (14) and the second liquid crystal cell (18) are TN-mode liquid crystal cells. The first optical compensation layer (12) has the smallest phase difference in the direction inclined from the normal direction of the first optical compensation layer when the phase difference is measured from the normal direction of the first optical compensation layer and from the direction inclined from the normal direction of the first optical compensation layer. The second optical compensation layer has the smallest phase difference in the direction inclined from the normal direction of the second optical compensation layer when the phase difference is measured from the normal direction of the second optical compensation layer and the direction inclined from the normal direction of the second optical compensation layer (20).

Description

Technical Field

[0001] This invention relates to a viewing angle control system and an image display device. Background Technology

[0002] Image display devices such as liquid crystal displays (LCDs) and organic electroluminescent (EL) displays are widely used as displays in car navigation systems, smartphones, and laptops. In these displays, although observers can view images from the desired direction, sometimes viewing direction-related controls are required, such as those that make it difficult to view images from other directions.

[0003] For example, in Patent Document 1, as a display device capable of controlling the viewing angle, a display device is disclosed that includes a first viewing angle control panel having a first liquid crystal layer having a first liquid crystal layer having a twisted orientation of liquid crystal molecules and a second viewing angle control panel having a second liquid crystal layer having a twisted orientation of liquid crystal molecules.

[0004] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2021-156943 Summary of the Invention

[0005] The technical problem to be solved by the invention On the other hand, in recent years, from the perspective of controlling the light emitted from the light source, it has been desirable to realize an optical system that has higher brightness near the front direction of the light source and lower brightness in the direction of tilt (tilt direction) from the front direction. In particular, as long as the optical system has low brightness in the tilt direction at a specified azimuth angle, it is possible to realize that when such an optical system is placed in front of the passenger seat of a vehicle, the image can be viewed from the passenger seat but not from the driver's seat.

[0006] Based on the inventors' research on the characteristics of the image display device described in Patent Document 1, it was found that the balance between high brightness in the front direction and low brightness in the tilt direction is not sufficient and further improvements are needed.

[0007] In view of the above facts, the objective of the present invention is to provide a viewing angle control system that, when applied to a light source, can achieve high brightness in the frontal direction and low brightness in the tilt direction at a specific azimuth angle.

[0008] Another objective of this invention is to provide an image display device.

[0009] means for solving technical problems The inventors have conducted in-depth research on the above-mentioned issues and discovered that the following structure can solve these issues.

[0010] (1) A perspective control system, which sequentially comprises: First polarizer; First optical compensation layer; First liquid crystal unit; Second polarizer; Second liquid crystal unit; Second optical compensation layer; and The third polarizer The first and second liquid crystal units are TN mode liquid crystal units. The first optical compensation layer is the layer with the smallest phase difference when measuring the phase difference from the normal direction of the first optical compensation layer and in the direction inclined from the normal direction of the first optical compensation layer. The second optical compensation layer is the layer with the smallest phase difference when the phase difference is measured from the normal direction of the second optical compensation layer and in the direction inclined from the normal direction of the second optical compensation layer.

[0011] (2) The perspective control system according to (1), wherein, The first optical compensation layer and the second optical compensation layer are layers made of liquid crystal compounds with fixed tilt orientation or mixed orientation.

[0012] (3) The perspective control system according to (2), wherein, The liquid crystal compound is either a disc-shaped liquid crystal compound or a rod-shaped liquid crystal compound.

[0013] (4) The perspective control system according to (2) or (3), wherein, In the first optical compensation layer, the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer is 45° to 135°. In the second optical compensation layer, the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer is 45° to 135°.

[0014] (5) The perspective control system according to any one of (1) to (4), wherein, A third optical compensation layer is further provided between the first liquid crystal cell and the second polarizer. A fourth optical compensation layer is further provided between the second polarizer and the second liquid crystal cell. The third optical compensation layer is the layer with the smallest phase difference when measuring the phase difference from the normal direction of the third optical compensation layer and in the direction inclined from the normal direction of the third optical compensation layer. The fourth optical compensation layer is the layer with the smallest phase difference when the phase difference is measured from the normal direction of the fourth optical compensation layer and in the direction inclined from the normal direction of the fourth optical compensation layer.

[0015] (6) An image display device having an image display element and a viewing angle control system as described in any one of (1) to (5).

[0016] Invention Effects According to the present invention, a viewing angle control system that can achieve high brightness in the frontal direction and low brightness in the tilt direction at a specific azimuth angle when applied to a light source can be provided.

[0017] According to the present invention, an image display device can be provided. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view of the first embodiment of the perspective control system of the present invention.

[0019] Figure 2 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axes of the first polarizer, the second polarizer, and the third polarizer in the viewing angle control system.

[0020] Figure 3 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axis of the first polarizer, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell, and the transmission axis of the second polarizer in the viewing angle control system.

[0021] Figure 4 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axis of the second polarizer, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal cell, and the transmission axis of the third polarizer in the viewing angle control system.

[0022] Figure 5 This is a diagram showing the orientation state of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal unit.

[0023] Figure 6 This is a diagram showing the orientation state of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal unit.

[0024] Figure 7 It means from Figure 6The diagram shows the results of visual recognition when the direction of the white arrow changes its azimuth and polar angle.

[0025] Figure 8 This is a diagram showing the orientation state of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal unit.

[0026] Figure 9 It means from Figure 8 The diagram shows the results of visual recognition when the direction of the white arrow changes its azimuth and polar angle.

[0027] Figure 10 It means Figure 7 and Figure 9 The diagram shows the area that is repeated within the range enclosed by thick lines.

[0028] Figure 11 This is a diagram showing the structure of the second liquid crystal unit and the second optical compensation layer.

[0029] Figure 12 This is a diagram showing the relationship between the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer.

[0030] Figure 13 This is a diagram showing the structure of the second optical compensation layer in a modified example of the first embodiment of the view control system of the present invention.

[0031] Figure 14 This is a diagram showing the relationship between the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer.

[0032] Figure 15 This is a schematic cross-sectional view of the second embodiment of the perspective control system of the present invention. Detailed Implementation

[0033] The present invention will now be described in detail.

[0034] The following description of the constituent elements is sometimes based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[0035] In addition, in this specification, the numerical range indicated by “~” refers to the range including the values ​​recorded before and after “~” as the lower and upper limits.

[0036] Furthermore, in this specification, parallel and orthogonal do not refer to parallel and orthogonal in the strict sense, but rather to the range of parallel ±5° (relative to the range of parallel ±5°) and orthogonal ±5° (relative to the range of orthogonal ±5°), respectively.

[0037] In this specification, "absorption axis" refers to the polarization direction in which the absorbance changes most significantly when linearly polarized light is incident. "Transmission axis" refers to the direction in which the absorption axis forms a 90° angle with the plane. Furthermore, "in-plane slow axis" refers to the direction in which the refractive index changes most significantly within the plane.

[0038] Furthermore, in this specification, Re(λ) and Rth(λ) represent the in-plane retardation and thickness retardation at wavelength λ, respectively. Unless otherwise specified, wavelength λ is set to 550 nm.

[0039] In this invention, Re(λ) and Rth(λ) are values ​​measured at wavelength λ using an AxoScan (manufactured by Axometrics). They are calculated by inputting the average refractive index ((nx+ny+nz) / 3) and film thickness (d(μm)) into the AxoScan. Slow axis direction (°) Re(λ) = R0(λ) Rth(λ)=((nx+ny) / 2-nz)×d.

[0040] Additionally, R0(λ) is displayed as a value calculated by AxoScan, representing Re(λ).

[0041] Furthermore, in this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by ATAGO CO.,LTD.) with a sodium lamp (λ=589nm) as the light source. Moreover, when measuring wavelength dependence, measurements can be performed using a multi-wavelength Abbe refractometer DR-M2 (manufactured by ATAGO CO.,LTD.) in combination with an interference filter.

[0042] Furthermore, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC.) and various optical film catalogs can be used. The following are examples of the average refractive index values ​​for major optical films: cellulose acylate (1.48), cyclic olefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0043] Furthermore, in this specification, each component may be used alone with one corresponding substance, or with two or more substances used together. Here, when two or more substances are used together for each component, unless otherwise stated, the content of the component refers to the total content of the substances used together.

[0044] Furthermore, in this specification, "(meth)acrylate" is the expression for "acrylate" or "methacrylate", "(meth)acrylic acid" is the expression for "acrylic acid" or "methacrylic acid", and "(meth)acryloyl" is the expression for "acryloyl" or "methacryloyl".

[0045] Figure 1 The first embodiment of the view control system of the present invention is shown in the figure.

[0046] Figure 1 The viewing angle control system 100A shown includes, in sequence, a first polarizer 10, a first optical compensation layer 12, a first liquid crystal cell 14, a second polarizer 16, a second liquid crystal cell 18, a second optical compensation layer 20, and a third polarizer 22. When this viewing angle control system 100A is positioned on a light source, and voltages are applied to the first liquid crystal cell 14 and the second liquid crystal cell 18 to turn them on, it can achieve high brightness in the frontal direction and low brightness in the tilt direction at a specific azimuth angle.

[0047] The following section will first explain how viewing angle control is performed through the first polarizer 10, the second polarizer 16, the third polarizer 22, the first liquid crystal unit 14, and the second liquid crystal unit 18.

[0048] Figure 2 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axes of the first polarizer 10, the second polarizer 16, and the third polarizer 22 in the viewing angle control system 100A. Additionally, Figure 2 The arrows in the first polarizer 10, the second polarizer 16, and the third polarizer 22 indicate the transmission axis.

[0049] The angle between the transmission axis of the first polarizer 10 and the transmission axis of the second polarizer 16 is 90°. Furthermore, the present invention is not limited to this. Figure 1 In this configuration, the angle between the transmission axis of the first polarizer and the transmission axis of the second polarizer is preferably in the range of 85° to 95°, and more preferably in the range of 88° to 92°. That is, it is preferable that the transmission axis of the first polarizer and the transmission axis of the second polarizer are orthogonal.

[0050] The angle between the transmission axis of the second polarizer 16 and the transmission axis of the third polarizer 22 is 90°. Furthermore, the present invention is not limited to this. Figure 1 In this configuration, the angle between the transmission axis of the second polarizer and the transmission axis of the third polarizer is preferably in the range of 85° to 95°, and more preferably in the range of 88° to 92°. That is, it is preferable that the transmission axis of the second polarizer and the transmission axis of the third polarizer are orthogonal.

[0051] Figure 3 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axis of the first polarizer 10, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell 14, and the transmission axis of the second polarizer 16 in the viewing angle control system 100A. Additionally, Figure 3 The arrows in the first polarizer 10 and the second polarizer 16 indicate the transmission axis.

[0052] exist Figure 3 The image shows the initial alignment state of the liquid crystal compound when no voltage is applied to the liquid crystal layer in the first liquid crystal cell 14 (off state). The first liquid crystal cell 14 is a so-called TN mode liquid crystal cell.

[0053] As described above, the angle between the transmission axis of the first polarizer 10 and the transmission axis of the second polarizer 16 is 90°.

[0054] The rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell 14 is twisted and oriented. More specifically, when taking the rod-shaped liquid crystal compound LC2 located on the side of the second polarizer 16 in the liquid crystal layer of the first liquid crystal cell 14 as a reference, the rod-shaped liquid crystal compound is twisted and oriented in a clockwise direction.

[0055] The configuration of the rod-shaped liquid crystal compound is described in detail below.

[0056] The long axis of the rod-shaped liquid crystal compound LC1, contained in the liquid crystal layer of the first liquid crystal cell 14 and located on the side of the first polarizer 10, forms an angle of 0° with the transmission axis of the first polarizer 10. Furthermore, the present invention is not limited to this. Figure 3 In this manner, the angle between the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell and the transmission axis of the first polarizer is preferably in the range of 0 to 5°, more preferably in the range of 0 to 2°. That is, preferably the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell and located on the first polarizer side is parallel to the transmission axis of the first polarizer.

[0057] The long axis of the rod-shaped liquid crystal compound LC2, contained in the liquid crystal layer of the first liquid crystal cell 14 and located on the side of the second polarizer 16, forms an angle of 0° with the transmission axis of the second polarizer 16. Furthermore, the present invention is not limited to this. Figure 3 In this configuration, the angle between the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell and located on the second polarizer side, and the transmission axis of the second polarizer, is preferably in the range of 0 to 5°, more preferably in the range of 0 to 2°. That is, preferably, the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell and located on the second polarizer side is parallel to the transmission axis of the second polarizer.

[0058] As mentioned above, in Figure 3 In this embodiment, the rod-shaped liquid crystal compound is twisted and oriented at a twist angle of 90°. However, this invention is not limited to this. Figure 3 In this manner, the twist angle is preferably in the range of 85 to 95°, and more preferably in the range of 88 to 92°.

[0059] exist Figure 3 In this process, the rod-shaped liquid crystal compound is oriented by twisting in a clockwise direction, but it can also be oriented by twisting in a counterclockwise direction.

[0060] Furthermore, as described later, the liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell may have a specified pretilt angle.

[0061] Figure 4 It means from Figure 1 When observing the direction of the white arrow, Figure 1 The diagram shows the relationship between the transmission axis of the second polarizer 16, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal cell 18, and the transmission axis of the third polarizer 22 in the viewing angle control system 100A. Additionally, Figure 4 The arrows in the second polarizer 16 and the third polarizer 22 indicate the transmission axis.

[0062] exist Figure 4 The image shows the initial alignment state of the liquid crystal compound when no voltage is applied to the liquid crystal layer in the second liquid crystal cell 18 (when it is turned off). The second liquid crystal cell 18 is a so-called TN mode liquid crystal cell.

[0063] As described above, the angle between the transmission axis of the second polarizer 16 and the transmission axis of the third polarizer 22 is 90°.

[0064] The rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal cell 18 is twisted and oriented. More specifically, with reference to the rod-shaped liquid crystal compound LC4 located on the third polarizer 22 side of the liquid crystal layer in the second liquid crystal cell 18, the rod-shaped liquid crystal compound is twisted and oriented in a clockwise direction.

[0065] The configuration of the rod-shaped liquid crystal compound is described in detail below.

[0066] The long axis of the rod-shaped liquid crystal compound LC3, contained in the liquid crystal layer of the second liquid crystal cell 18 and located on the side of the second polarizer 16, forms an angle of 0° with the transmission axis of the second polarizer 16. Furthermore, the present invention is not limited to this. Figure 4 In this configuration, the angle between the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal unit and the transmission axis of the second polarizer is preferably in the range of 0 to 5°, more preferably in the range of 0 to 2°. That is, preferably, the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal unit and located on the second polarizer side is parallel to the transmission axis of the second polarizer.

[0067] The long axis of the rod-shaped liquid crystal compound LC4, contained in the liquid crystal layer of the second liquid crystal cell 18 and located on the side of the third polarizer 22, forms an angle of 0° with the transmission axis of the third polarizer 22. Furthermore, the present invention is not limited to this. Figure 4 In this configuration, the angle between the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal unit and the transmission axis of the third polarizer is preferably in the range of 0 to 5°, more preferably in the range of 0 to 2°. Preferably, the long axis of the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal unit and located on the third polarizer side is parallel to the transmission axis of the third polarizer.

[0068] As mentioned above, in Figure 4 In this embodiment, the rod-shaped liquid crystal compound is twisted and oriented at a twist angle of 90°. However, this invention is not limited to this. Figure 4 In this manner, the twist angle is preferably in the range of 85 to 95°, and more preferably in the range of 88 to 92°.

[0069] exist Figure 4 In this process, the rod-shaped liquid crystal compound is oriented by twisting in a clockwise direction, but it can also be oriented by twisting in a counterclockwise direction.

[0070] Furthermore, as described later, the liquid crystal compound contained in the liquid crystal layer of the second liquid crystal cell may have a specified pretilt angle.

[0071] Figure 5 and Figure 6 This is a diagram showing the orientation state of the rod-shaped liquid crystal compound contained in the liquid crystal layer 24 of the second liquid crystal unit 18. Additionally, in Figure 5 and 6The image shows, in a representative manner, a rod-shaped liquid crystal compound LC10 contained in the liquid crystal layer 24 of the second liquid crystal cell 18 and located on the side of the second polarizer 16, a rod-shaped liquid crystal compound LC11 contained in the liquid crystal layer 24 of the second liquid crystal cell 18 and located on the side of the third polarizer 22, and a rod-shaped liquid crystal compound LC12 contained in the liquid crystal layer 24 of the second liquid crystal cell 18 and located at the middle position of the thickness of the liquid crystal layer 24. However, as described above, the rod-shaped liquid crystal compounds are twisted and oriented.

[0072] As described later, the second liquid crystal cell 18 has a liquid crystal layer 24 sandwiched between two substrates (the first substrate 26 and the second substrate 28). The structure of the second liquid crystal cell 18 will be described in detail later.

[0073] Figure 5 The initial orientation state of the rod-shaped liquid crystal compound LC is shown when no voltage is applied to the liquid crystal layer 24 in the second liquid crystal cell 18.

[0074] like Figure 5 As shown, when the voltage is not applied and the circuit is closed, the rod-shaped liquid crystal compounds (LC10 to LC12) are horizontally oriented. As described above, the twist angle of the rod-shaped liquid crystal compounds is 90°.

[0075] In addition, Figure 5 In this context, rod-shaped liquid crystal compounds LC10 and LC11 are horizontally oriented, but can also have a tilt angle.

[0076] Figure 6 This shows the orientation state of the rod-shaped liquid crystal compound LC when a voltage is applied to the liquid crystal layer 24 in the second liquid crystal cell 18. Additionally, Figure 6 The orientation state is shown when approximately half of the maximum voltage (e.g., around 2.5V) is applied.

[0077] like Figure 6 As shown, when the aforementioned voltage is applied, the rod-shaped liquid crystal compound tilts and aligns. In particular, as... Figure 6 As shown, the rod-shaped liquid crystal compound LC12 located in the middle of the liquid crystal layer 24 is prone to tilting due to the influence of voltage. At this time, the azimuth angle of the long axis of the rod-shaped liquid crystal compound LC12 remains almost unchanged.

[0078] On the other hand, the rod-shaped liquid crystal compound LC10 located on the side of the second polarizer 16 and the rod-shaped liquid crystal compound LC11 located on the side of the third polarizer 22 are difficult to tilt.

[0079] exist Figure 6In the structure of the second polarizer 16, the second liquid crystal cell 18, and the third polarizer 22 shown, a light source is arranged on the side opposite to the second liquid crystal cell 18 side of the second polarizer 16, and a voltage is applied to the liquid crystal layer 24 in the second liquid crystal cell 18 to make the rod-shaped liquid crystal compound... Figure 6 When tilted like that, it will be from Figure 6 The results of visual recognition when the direction of the white arrow changes its azimuth and polar angle are shown in the figure. Figure 7 middle.

[0080] Figure 7 The orientation on the right side of the paper corresponds to Figure 6 The front side of the arrow on the X-axis in the diagram. Figure 7 The direction on the left side of the paper corresponds to Figure 6 The rear end of the arrow on the X-axis in the diagram. Figure 7 The orientation of the bottom side of the paper corresponds to Figure 6 The front side of the paper in the middle, Figure 7 The orientation on the upper side of the paper corresponds to Figure 6 The back side of the paper.

[0081] Furthermore, the center of the concentric circles corresponds to the normal direction of the second liquid crystal unit 18, and the concentric circles of different sizes correspond to tilt angles (polar angles) of 20°, 40°, 60°, and 80° relative to the normal direction, respectively.

[0082] exist Figure 7 As described above, the following describes the result of visual recognition when a light source is arranged on the side opposite to the second liquid crystal cell 18 side of the second polarizer 16 and the azimuth angle and polar angle are changed from the third polarizer 22 side, for example, in the structure of the second polarizer 16, the second liquid crystal cell 18, and the third polarizer 22. Figure 7 The black dot in the image corresponds to the position of the result of visual identification from the polar angle of 40° along the azimuth angle of the front side facing the X-axis.

[0083] As a result, in Figure 7 Within the area indicated by the thick line, light is visually identifiable from a light source located on the side opposite to the second liquid crystal cell 18 of the second polarizer 16. In other areas, light is difficult to visually identify from the light source or is not visually identifiable. More specifically, in areas from... Figure 6 The azimuth angle of the front side in the X-axis direction and Figure 6 When visual recognition is performed by changing the polar angle of the azimuth angle in the middle of the azimuth angle on the front side of the paper, the orientation of the rod-shaped liquid crystal compound contained in the liquid crystal layer 24 of the second liquid crystal unit 18 affects the function of the liquid crystal layer 24 as a phase retardation layer, such as a λ / 2 plate. The polarization direction of the transmitted light from the second polarizer 16 is rotated to be parallel to the transmission axis direction of the third polarizer 22, and visual recognition is performed by transmitting light through the third polarizer 22. In contrast, when visual recognition is performed from... Figure 6 The azimuth angle of the rear end side in the X-axis direction and Figure 6 When visual recognition is performed by changing the polar angle of the azimuth angle in the middle of the azimuth angle behind the paper, the phase difference based on the rod-shaped liquid crystal compound contained in the liquid crystal layer 24 of the second liquid crystal unit 18 is almost not generated. Therefore, unlike the above, the liquid crystal layer 24 does not play the role of a phase difference layer, and the polarized light transmitted through the second polarizer 16 is absorbed by the third polarizer 22 and cannot be visually recognized.

[0084] That is, in the structure of the second polarizer 16, the second liquid crystal cell 18 and the third polarizer 22, by applying a voltage to the liquid crystal layer 24 of the second liquid crystal cell 18, light can be transmitted in a specific direction.

[0085] In addition, Figure 7 The functions of the structures of the second polarizer 16, the second liquid crystal unit 18 and the third polarizer 22 are described, but the structures of the first polarizer 10, the first liquid crystal unit 14 and the second polarizer 16 also show the same functions.

[0086] Figure 8 This is a diagram showing the orientation state of the rod-shaped liquid crystal compound contained in the liquid crystal layer 30 of the first liquid crystal unit 14. Additionally, in Figure 8 The image shows, in a representative manner, a rod-shaped liquid crystal compound LC20 contained in the liquid crystal layer 30 of the first liquid crystal cell 14 and located on the side of the first polarizer 10, a rod-shaped liquid crystal compound LC21 contained in the liquid crystal layer 30 of the first liquid crystal cell 14 and located on the side of the second polarizer 16, and a rod-shaped liquid crystal compound LC22 contained in the liquid crystal layer 30 of the first liquid crystal cell 14 and located at the middle position of the thickness of the liquid crystal layer 30. However, as described above, the rod-shaped liquid crystal compounds are twisted and oriented.

[0087] As described later, the first liquid crystal cell 14 has a liquid crystal layer 30 sandwiched between two substrates (the first substrate 32 and the second substrate 34). The structure of the first liquid crystal cell 14 will be described in detail later.

[0088] Figure 8 This shows the orientation state of the rod-shaped liquid crystal compound LC when a voltage is applied to the liquid crystal layer 30 in the first liquid crystal cell 14. Additionally, Figure 8 The orientation state is shown when approximately half of the maximum voltage (e.g., around 2.5V) is applied.

[0089] like Figure 8 As shown, when the aforementioned voltage is applied, the rod-shaped liquid crystal compound tilts and aligns. In particular, as... Figure 8As shown, the rod-shaped liquid crystal compound LC22 located in the middle of the liquid crystal layer 30 is prone to tilting due to the influence of voltage. At this time, the azimuth angle of the long axis of the rod-shaped liquid crystal compound LC22 remains almost unchanged.

[0090] On the other hand, the rod-shaped liquid crystal compound LC20 located on the side of the first polarizer 10 and the rod-shaped liquid crystal compound LC21 located on the side of the second polarizer 16 are difficult to tilt.

[0091] exist Figure 8 In the structure of the first polarizer 10, the first liquid crystal cell 14, and the second polarizer 16 shown, a light source is arranged on the side opposite to the first liquid crystal cell 14 side of the first polarizer 10, and a voltage is applied to tilt the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell 14, thereby tilting the light source. Figure 8 The results of visual recognition when the direction of the white arrow changes its azimuth and polar angle are shown in the figure. Figure 9 middle.

[0092] Figure 9 The orientation on the right side of the paper corresponds to Figure 8 The front side of the arrow on the X-axis in the diagram. Figure 9 The direction on the left side of the paper corresponds to Figure 8 The rear end of the arrow on the X-axis in the diagram. Figure 9 The orientation of the bottom side of the paper corresponds to Figure 8 The front side of the paper in the middle, Figure 9 The orientation on the upper side of the paper corresponds to Figure 8 The back side of the paper.

[0093] Furthermore, the center of the concentric circles corresponds to the normal direction of the first liquid crystal unit 14, and the concentric circles of different sizes correspond to tilt angles (polar angles) of 20°, 40°, 60°, and 80° relative to the normal direction, respectively.

[0094] exist Figure 9 As described above, this indicates the result of visual recognition when a light source is arranged on the side opposite to the side of the first liquid crystal cell 14 of the first polarizer 10 and the azimuth angle and polar angle are changed from the side of the second polarizer 16, in the structure of the first polarizer 10, the first liquid crystal cell 14, and the second polarizer 16.

[0095] As a result, in Figure 9 Within the range indicated by the thick line, light can be visually recognized from a light source located on the side opposite to the first liquid crystal cell 14 of the first polarizer 10. In other areas, it is difficult to visually recognize light from the light source or it is not visually recognized.

[0096] That is, in the structure of the first polarizer 10, the first liquid crystal cell 14 and the second polarizer 16, by applying a voltage to the liquid crystal layer 30 of the first liquid crystal cell 14, light can be transmitted in a specific direction.

[0097] As described above, the structures of the first polarizer 10, the first liquid crystal cell 14, and the second polarizer 16, as well as the structures of the second polarizer 16, the second liquid crystal cell 18, and the third polarizer 22, can control the viewing angle respectively.

[0098] Therefore, when the above two structures are combined in the thickness direction and the power supplies of both the first liquid crystal unit 14 and the second liquid crystal unit 18 are turned on, as follows: Figure 10 As shown, in Figure 7 and Figure 9 The light source can be visually identified within the area enclosed by thick lines.

[0099] This combination is also shown in the aforementioned Patent Document 1.

[0100] On the other hand, as mentioned above Figure 6 As shown, even when a voltage is applied to the liquid crystal layer 24 in the second liquid crystal cell 18, rod-shaped liquid crystal compounds LC10 and LC11 are difficult to align tilted like rod-shaped liquid crystal compound LC12. If rod-shaped liquid crystal compounds LC10 and LC11 are included, their function as a retardation layer of the liquid crystal layer 24 is reduced, and they may become a cause of light leakage in the viewing angle control system. In particular, the inventors know that the influence of rod-shaped liquid crystal compound LC11 is significant.

[0101] In this invention, by setting Figure 1 The second optical compensation layer 20 shown eliminates light leakage based on the aforementioned rod-shaped liquid crystal compound LC11.

[0102] Furthermore, when measuring the phase difference from the normal direction and the direction inclined from the normal direction of the second optical compensation layer, the second optical compensation layer 20 corresponds to the layer with the smallest phase difference in the direction inclined from the normal direction. A detailed explanation of the aforementioned layers will be provided later.

[0103] The reasons for eliminating the aforementioned light leakage are explained in detail below.

[0104] exist Figure 11 The structure of the second liquid crystal cell 18 and the second optical compensation layer 20 is shown in the diagram. Furthermore, the second liquid crystal cell 18 is... Figure 6 The power supply shown is in the on state. As described above, when the power supply is on in the second liquid crystal cell 18, it is difficult for the rod-shaped liquid crystal compound LC11 to tilt and align.

[0105] In contrast, the second optical compensation layer 20, which is formed by configuring a layer of disc-shaped liquid crystal compound DL1 with a fixed tilt orientation, eliminates the optical influence of rod-shaped liquid crystal compound LC11.

[0106] The disk-shaped liquid crystal compound DL1 has a disk surface parallel to the front-back direction of the paper. The projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound DL1 onto the surface (main surface) of the second optical compensation layer 20 is used as... Figure 12 The black arrow indicates this. Furthermore, the optical axis of the disk-shaped liquid crystal compound DL1 is an axis along the normal direction of the disk surface of the disk-shaped liquid crystal compound DL1. Also, the surface of the second optical compensation layer 20 corresponds to one of two main surfaces orthogonal to the thickness direction of the second optical compensation layer 20. The aforementioned main surface refers to the surface with the largest area in the second optical compensation layer 20.

[0107] Furthermore, the in-plane slow axis on the surface of the liquid crystal layer 24 on the side of the second optical compensation layer 20 in the second liquid crystal cell 18 is taken as... Figure 12 The white arrow indicates this. In addition, the aforementioned in-plane slow axis is also equivalent to the projection axis that projects the optical axis (long axis of the rod-shaped liquid crystal compound LC11) located on the side of the second optical compensation layer 20 of the liquid crystal layer 24 onto the surface of the second optical compensation layer 20.

[0108] like Figure 12 As shown, the angle between the black arrow and the white arrow is 0°. That is, in the second optical compensation layer 20, the angle between the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound DL1 onto the surface of the second optical compensation layer 20 and the in-plane slow axis on the surface of the liquid crystal layer 24 on the second optical compensation layer 20 side within the second liquid crystal cell 18 is 0°. The present invention is not limited to this method. The angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer on the second optical compensation layer side within the second liquid crystal cell is preferably 0 to 45°, more preferably 0 to 20°, further preferably 0 to 5°, and particularly preferably 0 to 2°. That is, in the second optical compensation layer, the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer on the second optical compensation layer side within the second liquid crystal cell is preferably parallel.

[0109] The angle between the disk surface of the disk-shaped liquid crystal compound DL1 in the second optical compensation layer 20 and the surface of the second optical compensation layer 20 is not particularly limited, but is preferably 10 to 45°, and more preferably 15 to 35°.

[0110] The angle formed by the azimuth angle of the end of the optical axis (major axis) of the rod-shaped liquid crystal compound LC11 on the surface of the liquid crystal layer 24 located on the side opposite to the side of the second optical compensation layer 20 within the second liquid crystal cell 18 towards the end of the second optical compensation layer 20, and the azimuth angle of the end of the optical axis of the disk-shaped liquid crystal compound DL1 on the side of the second liquid crystal cell 18 towards the end opposite to the side of the second liquid crystal cell 18, is 0°. The present invention is not limited to this method. The angle formed by the azimuth angle of the end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located on the side of the second optical compensation layer within the second liquid crystal cell towards the end of the second optical compensation layer, and the azimuth angle of the end of the optical axis of the disk-shaped liquid crystal compound on the side of the second liquid crystal cell towards the end opposite to the side of the second liquid crystal cell, is preferably 0 to 45°, more preferably 0 to 20°, further preferably 0 to 5°, and particularly preferably 0 to 2°. That is, the azimuth angle of the end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell, which is opposite to the side of the second optical compensation layer, toward the end of the second optical compensation layer, and the azimuth angle of the end of the optical axis of the disk-shaped liquid crystal compound on the side of the second liquid crystal cell, toward the end of the side opposite to the side of the second liquid crystal cell, are preferably parallel.

[0111] In addition, the aforementioned azimuth angle refers to Figure 11 The azimuth angle on the xy plane.

[0112] In the above Figure 10 In the illustrated embodiment, the second optical compensation layer 20 is described as comprising a disk-shaped liquid crystal compound DL1, but it can also be configured to comprise a rod-shaped liquid crystal compound. When the second optical compensation layer comprises a rod-shaped liquid crystal compound, the angle between the projection axis formed by projecting the optical axis of the rod-shaped liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the second liquid crystal cell on the side of the second optical compensation layer is preferably 0–45°, more preferably 0–20°, further preferably 0–5°, and particularly preferably 0–2°.

[0113] When the second optical compensation layer contains a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the second optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0114] When the second optical compensation layer contains a rod-shaped liquid crystal compound, the angle formed by the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell opposite to the side of the second optical compensation layer toward the end of the second optical compensation layer, and the azimuth angle from one end of the optical axis of the rod-shaped liquid crystal compound contained in the second optical compensation layer on the side of the second liquid crystal cell toward the end opposite to the side of the second liquid crystal cell, is preferably 135 to 225°, more preferably 160 to 200°, and even more preferably 175 to 185°.

[0115] Furthermore, as mentioned above Figure 8 As shown, even when a voltage is applied to the liquid crystal layer 30 in the first liquid crystal cell 14, rod-shaped liquid crystal compounds LC20 and LC21 are difficult to align tilted like rod-shaped liquid crystal compound LC22. If rod-shaped liquid crystal compounds LC20 and LC21 are included, their function as a retardation layer of the liquid crystal layer 30 is reduced, and they may become a cause of light leakage in the viewing angle control system. In particular, the inventors know that the influence of rod-shaped liquid crystal compound LC20 is significant.

[0116] In this invention, by setting Figure 1 The first optical compensation layer 12 shown eliminates light leakage based on the aforementioned rod-shaped liquid crystal compound LC20.

[0117] The first optical compensation layer 12 and Figure 11 The second optical compensation layer 20 shown is also a layer made of a disk-shaped liquid crystal compound with a fixed tilt orientation, and eliminates the optical effects of the rod-shaped liquid crystal compound LC20.

[0118] The projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound contained in the first optical compensation layer 12 onto the surface (main surface) of the first optical compensation layer 12 forms an angle of 0° with the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell 14 on the side of the first optical compensation layer 12. Furthermore, the surface of the first optical compensation layer 12 corresponds to one of two main surfaces orthogonal to the thickness direction of the first optical compensation layer 12. The aforementioned main surface refers to the surface with the largest area in the first optical compensation layer 12.

[0119] The present invention is not limited to this method. The angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer is preferably 0–45°, more preferably 0–20°, further preferably 0–5°, and particularly preferably 0–2°. That is, the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound contained in the first optical compensation layer onto the surface of the first optical compensation layer is preferably parallel to the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer.

[0120] The angle between the disk surface of the disk-shaped liquid crystal compound in the first optical compensation layer and the surface of the first optical compensation layer is not particularly limited, but is preferably 10 to 45°, and more preferably 15 to 35°.

[0121] The angle formed by the azimuth angle from one end of the optical axis (long axis) of the rod-shaped liquid crystal compound LC20 located on the surface of the liquid crystal layer 30 located on the side of the first optical compensation layer 10, toward the end opposite to the side of the first optical compensation layer 10, and the azimuth angle from one end of the optical axis of the disk-shaped liquid crystal compound contained in the first optical compensation layer 12, on the side opposite to the side of the first liquid crystal cell 14, toward the end of the first liquid crystal cell 14, is 0°. The present invention is not limited to this method. The angle formed by the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the first optical compensation layer side of the first liquid crystal cell toward the end opposite to the first optical compensation layer side, and the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the first optical compensation layer toward the end opposite to the first liquid crystal cell side, is preferably 0 to 45°, more preferably 0 to 20°, further preferably 0 to 5°, and particularly preferably 0 to 2°. That is, the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the first liquid crystal cell on the first optical compensation layer side toward the end opposite to the first optical compensation layer side, and the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the first optical compensation layer toward the end opposite to the first liquid crystal cell side, is preferably parallel.

[0122] In the above description, the first optical compensation layer is described as comprising a disk-shaped liquid crystal compound, but it can also be comprising a rod-shaped liquid crystal compound. When the first optical compensation layer comprises a rod-shaped liquid crystal compound, the angle between the projection axis formed by projecting the optical axis of the rod-shaped liquid crystal compound onto the surface of the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the first liquid crystal cell on the side of the first optical compensation layer is preferably within the range described above.

[0123] When the first optical compensation layer contains a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the first optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0124] When the first optical compensation layer contains a rod-shaped liquid crystal compound, the angle formed by the azimuth angle from one end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the first optical compensation layer side toward the end opposite to the first optical compensation layer side, and the azimuth angle from one end of the optical axis of the rod-shaped liquid crystal compound contained in the first optical compensation layer toward the end opposite to the first liquid crystal cell side, is preferably 135 to 225°, more preferably 160 to 200°, and even more preferably 175 to 185°.

[0125] As a variation of the first embodiment of the viewing angle control system of the present invention, examples can be listed where the optical axis directions of the liquid crystal compound contained in the first optical compensation layer and / or the second optical compensation layer are different.

[0126] More specifically, in Figure 13 In addition to using the second optical compensation layer 20A, the configuration corresponds to the structure of the view control system described in the first embodiment above.

[0127] The second optical compensation layer 20A is a layer formed by a fixedly tilted, disk-shaped liquid crystal compound DL2. Figure 11 The second optical compensation layer 20 shown is oriented differently from the optical axis of the disk-shaped liquid crystal compound.

[0128] exist Figure 13 In the structure shown, the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound DL2 onto the surface (main surface) of the second optical compensation layer 20A is used as... Figure 14 The black arrow indicates this. Furthermore, the optical axis of the disk-shaped liquid crystal compound DL2 is the axis along the normal direction of the disk surface of the disk-shaped liquid crystal compound DL2.

[0129] Furthermore, the in-plane slow axis on the surface of the liquid crystal layer 24 on the side of the second optical compensation layer 20A in the second liquid crystal cell 18 is used as... Figure 14 It is indicated by the white arrow.

[0130] like Figure 14 As shown, the angle between the black arrow and the white arrow is 90°. That is, in the second optical compensation layer 20A, the angle between the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound DL1 onto the surface of the second optical compensation layer 20A and the in-plane slow axis on the surface of the liquid crystal layer 24 on the side of the second optical compensation layer 20A in the second liquid crystal cell 18 is 90°.

[0131] The inventors discovered that, in the above Figure 13 In the structure shown, with Figure 10 Compared to the structure shown, light leakage is further suppressed, resulting in lower brightness in the tilt direction at a specific azimuth angle.

[0132] In addition, Figure 13 In the previous description, the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound DL2 onto the surface of the second optical compensation layer 20A in the second optical compensation layer 20A and the in-plane slow axis on the surface of the liquid crystal layer 24 in the second liquid crystal cell 18 on the side of the second optical compensation layer 20A were described as having an angle of 90°. However, the present invention is not limited to this method. The angle formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer in the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer is preferably 45 to 135°, more preferably 70 to 110°, and even more preferably 85 to 95°.

[0133] The angle between the disk surface of the disk-shaped liquid crystal compound DL2 in the second optical compensation layer 20A and the surface of the second optical compensation layer 20 is not particularly limited, but is preferably 10 to 45°, and more preferably 15 to 35°.

[0134] When the rod-shaped liquid crystal compound located on the side of the second optical compensation layer 20A of the liquid crystal layer 24 in the second liquid crystal cell 18 is taken as a reference, the rod-shaped liquid crystal compound is twisted in a clockwise direction. In this case, if the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound DL1 on the side of the second liquid crystal cell 18 toward the end opposite to the side of the second liquid crystal cell 18 is taken as a reference, the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound LC11 located on the surface of the second optical compensation layer 20 side of the liquid crystal layer 24 in the second liquid crystal cell 18 toward the end of the second optical compensation layer 20 side is located at a position rotated 90° counterclockwise. The present invention is not limited to this method. If the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the second optical compensation layer toward the end opposite to the second liquid crystal cell side is taken as a reference, then the azimuth angle from one end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second optical compensation layer side of the second liquid crystal cell toward the end of the second optical compensation layer side is preferably in the range of 45 to 135° in a counterclockwise rotation, more preferably in the range of 70 to 110°, and even more preferably in the range of 85 to 95°.

[0135] In addition, the aforementioned azimuth angle refers to Figure 13 The azimuth angle on the xy plane.

[0136] In the above description, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the second liquid crystal cell is described as having a clockwise twist orientation. However, the present invention is not limited to this orientation, and the rod-shaped liquid crystal compound may also be twisted in a counterclockwise direction. In the case of such a counterclockwise twist orientation, if the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the second optical compensation layer on the second liquid crystal cell side toward the end opposite to the second liquid crystal cell side is used as a reference, then the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer on the second optical compensation layer side of the second liquid crystal cell, toward the end opposite to the second optical compensation layer side, is preferably within the range of 45 to 135° clockwise rotation, more preferably within the range of 70 to 110° rotation, and even more preferably within the range of 85 to 95° rotation.

[0137] In the above Figure 13In the illustrated embodiment, the second optical compensation layer 20A is described as comprising a disk-shaped liquid crystal compound DL2, but it can also be described as comprising a rod-shaped liquid crystal compound. When the second optical compensation layer comprises a rod-shaped liquid crystal compound, the angle between the projection axis formed by projecting the optical axis of the rod-shaped liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the second liquid crystal cell on the side of the second optical compensation layer is preferably within the range described above.

[0138] Therefore, in the second optical compensation layer, the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer is preferably 45 to 135°.

[0139] When the second optical compensation layer contains a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the second optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0140] When the second optical compensation layer contains a rod-shaped liquid crystal compound, if the azimuth angle from one end of the optical axis of the rod-shaped liquid crystal compound contained in the second optical compensation layer on the second liquid crystal cell side toward the end opposite to the second liquid crystal cell side is taken as a reference, the preferred range of the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell on the second optical compensation layer side toward the end of the second optical compensation layer side is the same as the preferred range when the second optical compensation layer contains a disk-shaped liquid crystal compound.

[0141] The second optical compensation layer 20A has been described above, but the same tendency is also shown with respect to the first optical compensation layer.

[0142] Specifically, the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer is preferably 45 to 135°, more preferably 70 to 110°, and even more preferably 85 to 95°.

[0143] When the liquid crystal compound contained in the first optical compensation layer is a disk-shaped liquid crystal compound, there is no particular limitation on the angle between the disk surface of the disk-shaped liquid crystal compound and the surface of the first optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0144] When the liquid crystal compound contained in the first optical compensation layer is a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the first optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0145] When the rod-shaped liquid crystal compound located on the side opposite to the first optical compensation layer side (second polarizer side) of the liquid crystal layer in the first liquid crystal cell is used as a reference, the rod-shaped liquid crystal compound is twisted in a clockwise direction. In this case, if the azimuth angle from one end of the optical axis of the liquid crystal compound contained in the first optical compensation layer opposite to the first liquid crystal cell side toward the end of the first liquid crystal cell side is used as a reference, the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the first optical compensation layer side of the liquid crystal layer in the first liquid crystal cell toward the end opposite to the first optical compensation layer side is preferably in the range of 45 to 135° clockwise rotation, more preferably in the range of 70 to 110° clockwise rotation, and even more preferably in the range of 85 to 95° clockwise rotation.

[0146] In the above description, the rod-shaped liquid crystal compound contained in the liquid crystal layer of the first liquid crystal cell is described in a clockwise twist orientation. However, the present invention is not limited to this orientation, and the rod-shaped liquid crystal compound may also be twisted in a counterclockwise direction. In the case of such a counterclockwise twist orientation, if the azimuth angle from the end of the optical axis of the liquid crystal compound contained in the first optical compensation layer opposite to the side of the first liquid crystal cell toward the end of the first liquid crystal cell side is used as a reference, then the azimuth angle from the end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the first optical compensation layer side of the liquid crystal layer located in the first liquid crystal cell toward the end opposite to the side of the first optical compensation layer side in the counterclockwise direction is preferably in the range of 45 to 135°, more preferably in the range of 70 to 110°, and even more preferably in the range of 85 to 95°.

[0147] Figure 15 The second embodiment of the view control system of the present invention is shown in the figure.

[0148] Figure 15 The viewing angle control system 100B shown has, in sequence, a first polarizer 10, a first optical compensation layer 12, a first liquid crystal unit 14, a third optical compensation layer 40, a second polarizer 16, a fourth optical compensation layer 42, a second liquid crystal unit 18, a second optical compensation layer 20, and a third polarizer 22.

[0149] Regarding the viewing angle control system 100B, it has the same structure as the viewing angle control system 100A, except for having the third optical compensation layer 40 and the fourth optical compensation layer 42. When this viewing angle control system 100B is disposed on a light source and is turned on by applying voltage to the first liquid crystal cell 14 and the second liquid crystal cell 18 respectively, it can achieve high brightness in the frontal direction and low brightness in the tilt direction at a specific azimuth angle. In particular, the effect of the present invention is further enhanced by including the third optical compensation layer 40 and the fourth optical compensation layer 42 in the viewing angle control system 100B.

[0150] The third optical compensation layer 40, like the first optical compensation layer 12 and the second optical compensation layer 20, is a layer made of a disk-shaped liquid crystal compound with a fixed tilt orientation.

[0151] As mentioned above, regarding Figure 8 The rod-shaped liquid crystal compound LC21, which is contained in the liquid crystal layer 30 in the first liquid crystal cell 14 and located on the side of the second polarizer 16, is difficult to tilt and align even when the voltage is turned on to the liquid crystal layer 30.

[0152] By providing the third optical compensation layer 40, optical leakage caused by this rod-shaped liquid crystal compound LC21 can be suppressed.

[0153] The projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound contained in the third optical compensation layer 40 onto the surface (main surface) of the third optical compensation layer 40 forms an angle of 0° with the in-plane slow axis on the surface of the liquid crystal layer 30 in the first liquid crystal cell 14 on the side of the third optical compensation layer 40. Furthermore, the surface of the third optical compensation layer 40 corresponds to one of two main surfaces orthogonal to the thickness direction of the third optical compensation layer 40. The aforementioned main surface refers to the surface with the largest area in the third optical compensation layer 40.

[0154] The present invention is not limited to this method. The angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the third optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the third optical compensation layer is preferably 0 to 5°, more preferably 0 to 2°. That is, the projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound contained in the third optical compensation layer onto the surface of the third optical compensation layer is preferably parallel to the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell 14 on the side of the third optical compensation layer.

[0155] The angle between the disk surface of the disk-shaped liquid crystal compound in the third optical compensation layer 40 and the surface of the third optical compensation layer 40 is not particularly limited, but is preferably 10 to 45°, and more preferably 15 to 35°.

[0156] The angle formed by the azimuth angle of the end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer 30 located on the side opposite to the side of the third optical compensation layer 40 within the first liquid crystal cell 14 towards the end of the third optical compensation layer 40, and the azimuth angle of the end of the optical axis of the disc-shaped liquid crystal compound contained in the third optical compensation layer 40 on the side of the first liquid crystal cell 14 towards the end opposite to the side of the first liquid crystal cell 14, is 0°. The present invention is not limited to this method. The angle formed by the azimuth angle of the end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located on the side of the third optical compensation layer within the first liquid crystal cell towards the end of the third optical compensation layer, and the azimuth angle of the end of the optical axis of the disc-shaped liquid crystal compound on the side of the first liquid crystal cell towards the end opposite to the side of the first liquid crystal cell, is preferably 0 to 45°, more preferably 0 to 20°, further preferably 0 to 5°, and particularly preferably 0 to 2°. That is, the azimuth angle of the end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the first liquid crystal cell, which is opposite to the side of the third optical compensation layer, toward the end of the third optical compensation layer, and the azimuth angle of the end of the optical axis of the disk-shaped liquid crystal compound on the side of the first liquid crystal cell, toward the end of the side opposite to the side of the first liquid crystal cell, are preferably parallel.

[0157] In the above description, the third optical compensation layer 40 is described as comprising a disk-shaped liquid crystal compound, but it may also be comprising a rod-shaped liquid crystal compound. When the third optical compensation layer comprises a rod-shaped liquid crystal compound, the angle between the projection axis formed by projecting the optical axis of the rod-shaped liquid crystal compound onto the surface of the third optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the first liquid crystal cell on the side of the third optical compensation layer is preferably within the range described above.

[0158] When the third optical compensation layer contains a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the third optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0159] When the third optical compensation layer contains a rod-shaped liquid crystal compound, the angle formed by the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the first liquid crystal cell on the side opposite to the third optical compensation layer side toward the end of the third optical compensation layer side, and the azimuth angle from one end of the optical axis of the rod-shaped liquid crystal compound contained in the third optical compensation layer on the side opposite to the first liquid crystal cell side toward the end of the optical axis of the rod-shaped liquid crystal compound on the side opposite to the first liquid crystal cell side, is preferably 135 to 225°, more preferably 160 to 200°, and even more preferably 175 to 185°.

[0160] The fourth optical compensation layer 42, like the first optical compensation layer 12 and the second optical compensation layer 20, is a layer made of a disk-shaped liquid crystal compound with a fixed tilt orientation.

[0161] As mentioned above, regarding Figure 10 The rod-shaped liquid crystal compound LC10, which is contained in the liquid crystal layer 24 in the second liquid crystal cell 18 and located on the side of the second polarizer 16, is difficult to tilt and align even when the voltage is turned on to the liquid crystal layer 24.

[0162] By providing the fourth optical compensation layer 42, optical leakage caused by this rod-shaped liquid crystal compound LC10 can be suppressed.

[0163] The projection axis formed by projecting the optical axis of the disk-shaped liquid crystal compound contained in the fourth optical compensation layer 42 onto the surface (main surface) of the fourth optical compensation layer 42 forms an angle of 0° with the in-plane slow axis on the surface of the liquid crystal layer 24 in the second liquid crystal cell 18 on the side of the fourth optical compensation layer 42. Furthermore, the surface of the fourth optical compensation layer 242 corresponds to one of the two main surfaces orthogonal to the thickness direction of the fourth optical compensation layer 42. The aforementioned main surface refers to the surface with the largest area in the fourth optical compensation layer 42.

[0164] The present invention is not limited to this method. The angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the fourth optical compensation layer in the fourth optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the second liquid crystal cell on the side of the fourth optical compensation layer is preferably 0 to 5°, more preferably 0 to 2°. That is, in the fourth optical compensation layer, the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the fourth optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the second liquid crystal cell on the side of the fourth optical compensation layer are preferably parallel.

[0165] The angle between the disk surface of the disk-shaped liquid crystal compound in the fourth optical compensation layer 42 and the surface of the fourth optical compensation layer 42 is not particularly limited, but is preferably 10 to 45°, and more preferably 15 to 35°.

[0166] The angle formed by the azimuth angle from one end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the fourth optical compensation layer 42 side of the liquid crystal layer 24 located in the second liquid crystal cell 18 toward the end opposite to the fourth optical compensation layer 42 side, and the azimuth angle from one end of the optical axis of the disk-shaped liquid crystal compound contained in the fourth optical compensation layer 42 on the side opposite to the second liquid crystal cell 18 side toward the end of the second liquid crystal cell 18 side, is 0°. The present invention is not limited to this method. The angle formed by the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell towards the end opposite to the fourth optical compensation layer side, and the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the fourth optical compensation layer towards the end opposite to the second liquid crystal cell side, is preferably 0 to 45°, more preferably 0 to 20°, further preferably 0 to 5°, and particularly preferably 0 to 2°. That is, the azimuth angle from one end of the optical axis (major axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell towards the end opposite to the fourth optical compensation layer side, and the azimuth angle from one end of the optical axis of the disc-shaped liquid crystal compound contained in the fourth optical compensation layer towards the end opposite to the second liquid crystal cell side, is preferably parallel.

[0167] In the above description, the fourth optical compensation layer 42 is described as comprising a disk-shaped liquid crystal compound, but it may also be comprising a rod-shaped liquid crystal compound. When the fourth optical compensation layer comprises a rod-shaped liquid crystal compound, the angle between the projection axis formed by projecting the optical axis of the rod-shaped liquid crystal compound onto the surface of the fourth optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer within the second liquid crystal cell on the side of the fourth optical compensation layer is preferably within the range described above.

[0168] When the fourth optical compensation layer contains a rod-shaped liquid crystal compound, there is no particular limitation on the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the fourth optical compensation layer, which is preferably 10 to 45°, and more preferably 15 to 35°.

[0169] When the fourth optical compensation layer contains a rod-shaped liquid crystal compound, the angle formed by the azimuth angle from one end of the optical axis (long axis) of the rod-shaped liquid crystal compound on the surface of the liquid crystal layer located in the second liquid crystal cell on the fourth optical compensation layer side toward the end opposite to the second optical compensation layer side, and the azimuth angle from one end of the optical axis of the rod-shaped liquid crystal compound contained in the fourth optical compensation layer on the side opposite to the second liquid crystal cell side toward the end of the second liquid crystal cell side, is preferably 135 to 225°, more preferably 160 to 200°, and even more preferably 175 to 185°.

[0170] In the embodiments described above, the first to fourth optical compensation layers are all layers made of liquid crystal compounds (disc-shaped and rod-shaped liquid crystal compounds) with fixed tilt orientations, but the present invention is not limited to this method. For example, as described later, layers made of liquid crystal compounds with fixed mixed orientations may also be used.

[0171] The components included in the perspective control system of the present invention will be described in detail below.

[0172] <First polarizer, second polarizer and third polarizer> The first, second, and third polarizers can all be components that have the function of converting natural light into specific linearly polarized light; for example, an absorption polarizer can be listed.

[0173] There are no particular restrictions on the type of polarizer; commonly used polarizers can be used, such as iodine-based polarizers, dye-based polarizers utilizing dichroic substances, and polyolefin-based polarizers. Iodine-based and dye-based polarizers are usually manufactured by adsorbing iodine or dichroic dyes onto polyvinyl alcohol and then stretching it.

[0174] In addition, a protective film can be provided on one or both sides of the polarizer.

[0175] The configuration relationship of the first polarizer, the second polarizer, and the third polarizer is as described above.

[0176] <First liquid crystal unit and second liquid crystal unit> Both the first and second liquid crystal units are TN-mode liquid crystal units.

[0177] As described above, a TN-mode liquid crystal cell is a liquid crystal cell in which the liquid crystal compound contained within the liquid crystal cell is twisted and oriented. A TN-mode liquid crystal cell can rotate linearly polarized light incident on the liquid crystal cell by 80 to 100 degrees.

[0178] There are no particular restrictions on the structure of the first liquid crystal unit and the second liquid crystal unit. The structure of a well-known TN mode liquid crystal unit can be listed. As mentioned above, it usually includes two substrates and a liquid crystal layer disposed between the two substrates.

[0179] There are no particular restrictions on the types of liquid crystal compounds contained in the liquid crystal layer; examples of known liquid crystal compounds used in TN mode liquid crystal cells can be listed.

[0180] <Optical compensation layer 1 to optical compensation layer 4> As described above, the first to fourth optical compensation layers (hereinafter, these layers are also simply referred to as "optical compensation layers") are layers disposed between the components.

[0181] When measuring the phase difference from the normal direction of the optical compensation layer and from the direction tilted from the normal direction, these optical compensation layers (the first optical compensation layer to the fourth optical compensation layer) are the layers with the smallest phase difference in the direction tilted from the normal direction.

[0182] That is, when measuring the phase difference from the normal direction of the first optical compensation layer and from the direction inclined from the normal direction, the first optical compensation layer is the layer with the smallest phase difference in the direction inclined from the normal direction. Furthermore, the phase difference measured from the normal direction of the first optical compensation layer is the phase difference within a plane orthogonal to the normal direction of the first optical compensation layer, and the phase difference measured from the direction inclined from the normal direction of the first optical compensation layer is the phase difference within a plane orthogonal to the direction inclined from the normal direction of the first optical compensation layer.

[0183] Furthermore, when measuring the phase difference from the normal direction of the second optical compensation layer and from the direction inclined from the normal direction, the second optical compensation layer is the layer with the smallest phase difference in the direction inclined from the normal direction. Additionally, the phase difference measured from the normal direction of the second optical compensation layer is the phase difference within a plane orthogonal to the normal direction of the second optical compensation layer, and the phase difference measured from the direction inclined from the normal direction of the second optical compensation layer is the phase difference within a plane orthogonal to the direction inclined from the normal direction of the second optical compensation layer.

[0184] Furthermore, when measuring the phase difference from the normal direction of the third optical compensation layer and from the direction inclined from the normal direction, the third optical compensation layer is the layer with the smallest phase difference in the direction inclined from the normal direction. Additionally, the phase difference measured from the normal direction of the third optical compensation layer is the phase difference within a plane orthogonal to the normal direction of the third optical compensation layer, and the phase difference measured from the direction inclined from the normal direction of the third optical compensation layer is the phase difference within a plane orthogonal to the direction inclined from the normal direction of the third optical compensation layer.

[0185] Furthermore, when measuring the phase difference from the normal direction of the fourth optical compensation layer and from the direction inclined from the normal direction, the fourth optical compensation layer is the layer with the smallest phase difference in the direction inclined from the normal direction. Additionally, the phase difference measured from the normal direction of the fourth optical compensation layer is the phase difference within a plane orthogonal to the normal direction of the fourth optical compensation layer, and the phase difference measured from the direction inclined from the normal direction of the fourth optical compensation layer is the phase difference within a plane orthogonal to the direction inclined from the normal direction of the fourth optical compensation layer.

[0186] More specifically, when performing Measurement 1 and Measurement 2 below, the optical compensation layer (first optical compensation layer to fourth optical compensation layer) is the layer that represents the minimum phase difference in Measurement 2.

[0187] Measurement 1: The phase difference is measured from the normal direction of the optical compensation layer.

[0188] Measurement 2: The phase difference is measured by changing the tilt angle along the in-plane slow axis of the optical compensation layer or in a direction orthogonal to the in-plane slow axis from the normal direction.

[0189] The methods for performing Measurement 1 and Measurement 2 are described in detail below.

[0190] The above measurements were performed using a Mueller matrix measured at a wavelength of 550 nm using AxoScan (manufactured by Axometrics). Specifically, using AxoScan's "Two-Axis Out-of-Plane Retardance Measurement" mode, the in-plane slow axis and in-plane fast axis directions of the optical compensation layer were initially measured. Then, along the measured in-plane slow axis and in-plane fast axis directions, the measurement angle was changed every 1° from the polar angle of -75° to 75°, and the Mueller matrix at a wavelength of 550 nm was measured. The tilt orientation angle was calculated from the change in phase difference. When the angle of minimum phase difference was not 0°, the optical compensation layer of the measured object corresponded to the layer with the minimum phase difference in the direction tilted from the normal direction.

[0191] Examples of layers exhibiting the aforementioned characteristics include layers formed by fixing a liquid crystal compound with the aforementioned tilted orientation and layers formed by fixing a liquid crystal compound with a mixed orientation. As described above, these layers can suppress light leakage from the liquid crystal compounds within the first and second liquid crystal cells.

[0192] Furthermore, as an optical compensation layer, as long as it exhibits the above-mentioned characteristics, it can be a layer that is not formed using liquid crystal compounds, such as a resin film.

[0193] As an optical compensation layer, it is preferably a layer made of a liquid crystal compound with a fixed tilt orientation or a mixed orientation.

[0194] Tilt orientation refers to the orientation of a liquid crystal compound from one surface to another at a constant tilt angle. A constant tilt angle means that the angle difference between the tilt angles is within 10°.

[0195] Mixed orientation refers to the orientation in which the tilt angle of the liquid crystal compound changes continuously from one surface to another.

[0196] Examples of liquid crystal compounds mentioned above include disc-shaped liquid crystal compounds and rod-shaped liquid crystal compounds.

[0197] As a rod-shaped liquid crystal compound, the preferred compounds are those described in, for example, claims 1 of Japanese Patent Application Publication No. 11-513019 or paragraphs

[0026] to

[0098] of Japanese Patent Application Publication No. 2005-289980. As a disc-shaped liquid crystal compound, the preferred compounds are those described in, for example, paragraphs

[0020] to

[0067] of Japanese Patent Application Publication No. 2007-108732 or paragraphs

[0013] to

[0108] of Japanese Patent Application Publication No. 2010-244038.

[0198] The liquid crystal compound is preferably a polymerizable group. That is, the liquid crystal compound is preferably a polymerizable liquid crystal compound. Examples of polymerizable groups in a liquid crystal compound include free radical polymerizable groups such as acryloyl, methacryloyl, and vinyl groups, as well as cationic polymerizable groups such as epoxy groups.

[0199] By polymerizing this polymerizable liquid crystal compound, the orientation of the liquid crystal compound can be fixed. Furthermore, after the liquid crystal compound is fixed through polymerization, the liquid crystal properties are no longer required.

[0200] As described later, the optical compensation layer (first optical compensation layer to fourth optical compensation layer) is preferably a layer formed using a composition containing a liquid crystal compound having polymerizable groups.

[0201] The in-plane delay at a wavelength of 550 nm (the in-plane delay at a wavelength of 550 nm measured from the normal direction of the optical compensation layer) of the optical compensation layer (first optical compensation layer to fourth optical compensation layer) is not particularly limited, but is preferably 15 to 120 nm, and more preferably 15 to 65 nm.

[0202] The thickness of the optical compensation layers (first optical compensation layer to fourth optical compensation layer) is not particularly limited, but is preferably 0.3 to 2.0 μm, more preferably 0.5 to 1.5 μm.

[0203] The following describes in detail a method for manufacturing optical compensation layers (first optical compensation layer to fourth optical compensation layer) using a composition containing a liquid crystal compound having polymerizable groups.

[0204] The liquid crystal compound containing polymerizable groups (hereinafter also referred to as "polymerizable liquid crystal compound") in the composition is as described above. Furthermore, as described above, rod-shaped and disk-shaped liquid crystal compounds are appropriately selected based on the characteristics of the formed optical compensation layer.

[0205] The content of the polymerizable liquid crystal compound in the composition is preferably 60 to 99% by mass relative to the total solid content of the composition, more preferably 70 to 98% by mass.

[0206] In addition, solid components refer to components that can form an optical compensation layer after the solvent is removed, even if they are in liquid form.

[0207] The composition may contain compounds other than liquid crystal compounds having polymerizable groups.

[0208] The composition may contain a polymerization initiator. The polymerization initiator used is selected according to the form of polymerization reaction; for example, thermal polymerization initiators and photopolymerization initiators can be listed.

[0209] The content of polymerization initiator in the composition is preferably 0.01 to 20% by mass relative to the total solid content of the composition, more preferably 0.5 to 10% by mass.

[0210] Other components that may be included in the composition, in addition to those mentioned above, may include multifunctional monomers, orientation control agents (vertical orientation agents, horizontal orientation agents), surfactants, adhesion improvers, plasticizers, and solvents.

[0211] Examples of coating methods for the composition include curtain coating, dip coating, spin coating, printing coating, spraying, slot coating, roller coating, sliding coating, doctor blade coating, gravure coating, and wire rod coating.

[0212] Next, the formed coating film is subjected to an orientation treatment to orient the polymeric liquid crystal compounds in the coating film. For example, in the case of forming a layer of liquid crystal compounds with a fixed tilt orientation, the polymeric liquid crystal compounds are tilted and oriented. Furthermore, in the case of forming a layer of liquid crystal compounds with a fixed mixed orientation, the polymeric liquid crystal compounds are mixed and oriented.

[0213] Orientation processing can be performed by drying the coating at room temperature or by heating the coating. When the liquid crystal phase formed during orientation processing is a thermotropic liquid crystal compound, it can typically be transferred by changes in temperature or pressure. In the case of a lyotropic liquid crystal compound, transfer can also be achieved through compositional ratios such as solvent volume.

[0214] In addition, there are no particular restrictions on the conditions for heating the coating. The preferred heating temperature is 50 to 250°C, more preferably 50 to 150°C, and the preferred heating time is 10 seconds to 10 minutes.

[0215] Furthermore, after heating the coating and before the curing process (light irradiation treatment) described later, the coating can be cooled as needed.

[0216] Next, the coating film oriented with polymeric liquid crystal compound is cured.

[0217] There are no particular limitations on the method of curing the coating film oriented with polymeric liquid crystal compounds; for example, light irradiation and heat treatment can be included. However, from the viewpoint of manufacturing applicability, light irradiation is preferred, and ultraviolet irradiation is more preferred.

[0218] There are no particular restrictions on the irradiation conditions for light treatment, but 50–1000 mJ / cm² is preferred. 2 The amount of radiation.

[0219] There are no particular restrictions on the atmosphere during light irradiation treatment, but a nitrogen atmosphere is preferred.

[0220] <Manufacturing Method of View Control System> There are no particular limitations on the manufacturing method of the view control system. Various components mentioned above can be prepared and stacked using methods such as bonding layers.

[0221] <Uses> The perspective control system of the present invention is applicable to a variety of uses.

[0222] For example, the viewing angle control system of the present invention can be applied to an image display device. More specifically, the image display device of the present invention includes an image display element and the above-described viewing angle control system (first embodiment to second embodiment).

[0223] Examples of image display elements include liquid crystal display elements and organic electroluminescent display elements.

[0224] When the view control system is configured on the image display element, there are no particular restrictions on its stacking direction.

[0225] For example, when the viewing angle control system described in the first method is configured on the image display element, the first polarizer side can be provided on the image display element side and the viewing angle control system can be stacked on the image display element, or the third polarizer side can be provided on the image display element side and the viewing angle control system can be stacked on the image display element.

[0226] In addition, the image display device of the present invention may have a curved shape.

[0227] Example The following examples illustrate the features of the present invention in further detail. Furthermore, appropriate modifications can be made as long as the materials, amounts, proportions, processing contents, and processing order shown below do not depart from the spirit of the present invention. Moreover, configurations other than those shown below can also be employed as long as the spirit of the present invention is not departed from it.

[0228] <Example 1> The following is a layer of liquid crystal compound with tilted orientation.

[0229] (Fabrication of transparent support 1) The surface of cellulose acylated membrane 1 (40 μm thick TAC substrate; TG40 FUJIFILM Corporation) was saponified with alkali solution, and the following alignment layer forming coating solution 1 was applied onto it using a wire rod. The support with the coated film was dried with hot air at 60°C for 60 seconds, and then further dried with hot air at 100°C for 120 seconds to form alignment layer 1, thus obtaining a TAC film with an alignment layer. The thickness of the alignment layer was 0.5 μm.

[0230] The orientation film surface of the TAC film with the orientation layer is further rubbed before use.

[0231] ―――――――――――――――――――――― (Coating liquid 1 for forming orientation layer) ―――――――――――――――――――――― • 3.80 parts by weight of the following modified polyvinyl alcohol • Initiator Irg2959 0.20 parts by weight 70 parts by weight of water ·Methanol 30 parts by weight ―――――――――――――――――――――― Modified polyvinyl alcohol [Chemical Formula 1] (Fabrication of liquid crystal layer for orientation) Using a wire rod, an alignment liquid crystal layer forming composition T1 with the following composition is coated onto the alignment film of a TAC film with an alignment layer, thereby forming a coating layer T1.

[0232] Next, the alignment liquid crystal coating layer T1 is heated at 120°C for 30 seconds, and then cooled to room temperature (23°C). It is then further heated at 80°C for 60 seconds, and then cooled to room temperature again.

[0233] Subsequently, LED lights (center wavelength 365nm) were used at an illuminance of 200mW / cm². 2 The liquid crystal layer T1 for alignment was fabricated on the alignment layer 1 by irradiating it for 1 second under the specified irradiation conditions. The thickness of the liquid crystal layer T1 for alignment was 0.45 μm.

[0234] ――――――――――――――――――――――――― Composition of the liquid crystal layer forming composition T1 for orientation ――――――――――――――――――――――――― • 55.20 parts by weight of the following polymeric liquid crystal compound P-1 • 40.49 parts by weight of the following low molecular weight liquid crystal compound M-1 Polymerization initiators IRGACUREOXE-02 (manufactured by BASF) 4.049 parts by weight • 0.2620 parts by weight of the following surfactant F-1 · Cyclopentanone 660.6 parts by weight ·Tetrahydrofuran 660.6 parts by weight ――――――――――――――――――――――――― P-1, a polymeric liquid crystal compound [Chemical Formula 2] Low molecular weight liquid crystal compound M-1 [Chemical Formula 3] Surfactant F-1 [Chemical Formula 4] (Formation of tilted orientation layer A) The following tilted alignment layer coating liquid A is applied onto the obtained alignment liquid crystal layer T1 using a wire rod to form a coating film.

[0235] Next, the coating was heated at 60°C for 60 seconds. Afterward, the coating was subjected to UV irradiation at 60°C to fix the orientation of the liquid crystal compound, forming a tilted alignment layer A. The thickness of the tilted alignment layer A is 0.6 μm.

[0236] (Determination of orientation angle) For the optical film containing the aforementioned tilted alignment layer A, the alignment angle was determined by measuring the Mueller matrix at a wavelength of 550 nm using AxoScan (manufactured by Axometrics). Specifically, using AxoScan's "Two-Axis Out-of-Plane Retardance Measurement" mode, the in-plane slow axis and in-plane fast axis directions were initially measured. Then, in the measured in-plane slow axis and in-plane fast axis directions, the measurement angle was changed every 1° from the polar angle of -75° to 75°, and the Mueller matrix at a wavelength of 550 nm was measured. The tilted alignment angle was calculated from the change in phase difference. It was confirmed that the angle with the smallest phase difference was not 0° (normal direction).

[0237] The measurement results show that the in-plane retardation at a wavelength of 550 nm, measured from the normal direction of the tilted alignment layer A, is 20 nm, and the tilt angle (the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the tilted alignment layer A) is 30°.

[0238] ―――――――――――――――――――――――――――――― Composition of tilted alignment layer coating liquid A ―――――――――――――――――――――――――――――― • 6.61 parts by weight of the following rod-shaped liquid crystal compound-1 • 1.65 parts by weight of the following rod-shaped liquid crystal compound-2 • Photopolymerization initiator (Irgacure 907, manufactured by BASF) 0.34 parts by weight • Sensitizer (KAYACURE DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.11 parts by weight • 0.01 parts by weight of the following surfactant F-1 91.29 parts by weight of methyl ethyl ketone ―――――――――――――――――――――――――――――― Rod-shaped liquid crystal compound-1 [Chemical Formula 5] Rod-shaped liquid crystal compound-2 [Chemical Formula 6] Surfactant F-1 [Chemical Formula 7] (Making of polarizers) A polarizer with a thickness of 8 μm and one side of the polarizer exposed was manufactured using the same method as described in International Publication No. 2015 / 166991 for a polarizer with a single-sided protective film.

[0239] (Fabrication of TN LCD cell for viewing angle opening and closing) A horizontally oriented polyimide alignment film was coated onto two glass substrates with ITO electrodes. After high-temperature drying to form the alignment film, a tribological process was performed to enable the formation of TN cells. Specifically, the alignment process was performed by twisting the substrate vertically by 90°.

[0240] Next, a thermosetting sealing material is spread on one of the two substrates, and a microbead spacer is spread on the other. After the two substrates are bonded together, they are vacuum-packed and heated to form an empty liquid crystal cell.

[0241] A TN liquid crystal cell with a cell gap of 8 μm was fabricated by injecting liquid crystal (Merck KGaA MLC-9100) with positive dielectric anisotropy and refractive index anisotropy of Δn=0.0854 (589nm, 20℃) and Δε=+8.5 into the cell using a vacuum liquid crystal injector.

[0242] Furthermore, due to the friction treatment performed on the inner surfaces of the upper and lower substrates, the liquid crystal layer is twisted and aligned between the upper and lower substrates at a twist angle of 90° when no voltage is applied. By applying a voltage (2V), a TN liquid crystal cell with the liquid crystal aligned in the tilt direction is completed (reference). Figure 6 , 8 ).

[0243] (The creation of the view control system 1) Using a commercially available adhesive (manufactured by Soken Chemical & Engineering Co., Ltd., SK2057), the aforementioned tilted alignment layer A, the aforementioned polarizer, and the aforementioned TN liquid crystal cell were bonded together to create a viewing angle control system 1 that consists of a polarizer (polarizer-1) / tilted alignment layer A (tilted alignment layer A-1) / TN liquid crystal cell (TN liquid crystal cell-1) / polarizer (polarizer-2) / TN liquid crystal cell (TN liquid crystal cell-2) / tilted alignment layer (tilted alignment layer A-2) / polarizer (polarizer-3).

[0244] Alternatively, the name in parentheses above can be used in the latter part.

[0245] At this point, the absorption axes of polarizer-1 and polarizer-3 are aligned at an azimuth angle of 90°, and the absorption axis of polarizer-2 is aligned at an azimuth angle of 0°. That is, the transmission axes of polarizer-1 and polarizer-3 are aligned at an azimuth angle of 0°, and the transmission axis of polarizer-2 is aligned at an azimuth angle of 90°.

[0246] Furthermore, the azimuth angle when the direction of the optical axis of the liquid crystal compound in the tilted alignment layer A-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the tilted alignment layer A-1 is 0°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound in the tilted alignment layer A-2 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the tilted alignment layer A-2 is 0°.

[0247] Furthermore, the in-plane slow axis on the surface of the liquid crystal layer on the tilted alignment layer A-1 side in the TN liquid crystal cell-1 is parallel to the projection axis formed by projecting the optical axis of the liquid crystal compound in the tilted alignment layer A-1 onto the surface of the tilted alignment layer A-1. Also, the in-plane slow axis on the surface of the liquid crystal layer on the polarizer-2 side in the TN liquid crystal cell-1 is parallel to the transmission axis of the polarizer-2.

[0248] Furthermore, the azimuth angle when the direction of the optical axis of the liquid crystal compound on the tilted alignment layer A-1 side of the liquid crystal layer in the TN liquid crystal cell-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the polarizer-2 is 180°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound on the polarizer-2 side of the liquid crystal layer in the TN liquid crystal cell-1 (from the front end of the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the polarizer-2 is 90°.

[0249] Furthermore, the in-plane slow axis on the surface of the liquid crystal layer on the tilted alignment layer A-1 side in the TN liquid crystal cell-2 is parallel to the projection axis formed by projecting the optical axis of the liquid crystal compound in the tilted alignment layer A-1 onto the surface of the tilted alignment layer A-1. Also, the in-plane slow axis on the surface of the liquid crystal layer on the polarizer-2 side in the TN liquid crystal cell-1 is parallel to the transmission axis of the polarizer-2.

[0250] Furthermore, the azimuth angle when the direction of the optical axis of the liquid crystal compound on the polarizer-2 side of the liquid crystal layer in the TN liquid crystal cell-1 (from the front end of the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the polarizer-3 is 270°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound on the polarizer-3 side of the liquid crystal layer in the TN liquid crystal cell-2 (from the front end of the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the polarizer-3 is 180°.

[0251] (Fabrication of image display device 1 with viewing angle opening and closing function) The aforementioned viewing angle control system 1 was placed on the display screen of a dynabook (manufactured by TOSHIBA CORPORATION) equipped with a liquid crystal display device, thus creating an image display device 1 with a viewing angle opening and closing function. At this time, the absorption axis of the polarizer configured to be located on the visual recognition side of the dynabook is parallel to the absorption axis of the polarizer-3 of the viewing angle control system 1.

[0252] <Example 2> (Fabrication of Orientation Film 2) A saponified cellulose acylated membrane 1, prepared in Example 1, was prepared. On the other hand, the coating solution for the orientation membrane 2 was prepared by heating at 85°C for one hour while stirring, and then filtered through a 0.45 μm filter.

[0253] Orientation film 2 coating solution ―――――――――――――――――――――― • PVA203 (polyvinyl alcohol produced by Kuraray Co., Ltd.) 2.4 parts by weight · 97.6 parts by weight of pure water ―――――――――――――――――――――― While adjusting the coating amount, the prepared orientation film 2 coating solution was coated onto the saponified cellulose acylated film 1 so that the film thickness after drying was 0.5 μm. The obtained coating was dried at 100 °C for 2 minutes.

[0254] A temporary film-like support was created by subjecting the dried coating to a friction treatment. The direction of the friction treatment was set to be parallel to the length of the film.

[0255] (Formation of liquid crystal layer X1) The following polymerizable liquid crystal composition X1 was stirred at room temperature to obtain a homogeneous solution. It was then filtered using a 0.45 μm filter.

[0256] Polymerizable liquid crystal composition X1 ―――――――――――――――――――――― 100 parts by weight of the following disc-shaped liquid crystal compound B-1 The following polymeric monomer S1 10 parts by weight Polymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by weight 339 parts by weight of methyl ethyl ketone ―――――――――――――――――――――― Disc-shaped liquid crystal compound B-1 (polymerizable bithionene-type disc-shaped liquid crystal compound) [Chemical Formula 8] Polymerizable monomer S1 [Chemical Formula 9] To achieve a film thickness of 0.6 μm after drying and UV exposure, the prepared polymeric liquid crystal composition X1 was coated onto the friction surface side of the temporary support while adjusting the coating amount, and the coating was then dried. The resulting coating was then subjected to UV exposure to photocur and fix the orientation of the entire surface, forming the liquid crystal layer X1. The drying conditions were 105°C for 2 minutes, and the UV exposure conditions were 80 mW / cm². 2 500mJ / cm 2 The temperature was 80℃. Furthermore, nitrogen purging was performed during ultraviolet exposure, and exposure was conducted in an atmosphere with an oxygen concentration of 100 ppm.

[0257] (Formation of liquid crystal layer Y1) The following polymerizable liquid crystal composition Y1 was prepared by stirring at room temperature to obtain a homogeneous solution. Subsequently, it was filtered using a 0.45 μm filter.

[0258] Polymerizable liquid crystal composition Y1 ―――――――――――――――――――――― 80 parts by weight of the following disc-shaped liquid crystal compound A-1 20 parts by weight of the following disc-shaped liquid crystal compound A-2 10 parts by mass of the above polymerizable monomer S1 The following polymer C-1 1.0 parts by weight Polymerization initiator (Irgacure 907, manufactured by BASF) 5 parts by weight 356 parts by weight of methyl ethyl ketone ―――――――――――――――――――――― Disc-shaped liquid crystal compound A-1 (1,3,5-substituted benzene-type polymeric disc-shaped liquid crystal compound) [Chemical Formula 10] Disc-shaped liquid crystal compound A-2 (1,3,5-substituted benzene-type polymeric disc-shaped liquid crystal compound) [Chemical Formula 11] Polymer C-1 [Chemical Formula 12] The numbers mentioned above represent the mass percentage of each constituent unit relative to all constituent units of polymer C-1, from left to right: 32.5% mass, 17.5% mass, and 50.0% mass.

[0259] While adjusting the coating amount, the polymeric liquid crystal composition Y1 was coated onto the liquid crystal layer X1 prepared above, so that the film thickness after drying and ultraviolet exposure was 0.6 μm. The coating was then dried. The obtained coating was subjected to ultraviolet exposure to cure and fix the orientation of the entire surface, forming the liquid crystal layer Y1. The drying conditions were 120°C for 2 minutes, and the ultraviolet exposure conditions were 80 mW / cm². 2 500mJ / cm 2 The temperature was 80℃. Furthermore, nitrogen purging was performed during ultraviolet exposure, and exposure was conducted in an atmosphere with an oxygen concentration of 100 ppm.

[0260] Through the above operations, a tilted alignment layer B having liquid crystal layer X1 and liquid crystal layer Y1 was fabricated.

[0261] The results of measuring the optical film containing the tilted alignment layer B prepared above were determined according to the method described above, and it was confirmed that the angle with the smallest phase difference was not 0° (normal direction).

[0262] The measurement results show that the in-plane retardation at a wavelength of 550 nm, measured from the normal direction of the tilted alignment layer B, is 55 nm, and the tilt angle (the angle between the long axis of the rod-shaped liquid crystal compound and the surface of the tilted alignment layer B) is 30°.

[0263] (The creation of image display device 2 with viewing angle opening and closing function) Tilt alignment layer B (tilt alignment layer B-1, tilt alignment layer B-2) is used instead of tilt alignment layer A. The azimuth angle when the direction of the optical axis of the liquid crystal compound in tilt alignment layer B-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of tilt alignment layer B-1 is 180°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound in tilt alignment layer B-2 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of tilt alignment layer B-2 is 180°. Otherwise, an image display device 2 with viewing angle opening and closing function is manufactured in the same manner as in Example 1.

[0264] <Example 3> (Fabrication of the transparent support) The following composition was added to a mixing vessel and stirred while heating to 30°C to dissolve the components, thus preparing a cellulose acetate solution. Furthermore, two doping solutions were prepared as the cellulose acetate solution: an inner layer doping solution and an outer layer doping solution.

[0265] ―――――――――――――――――――――――――――――――― Composition of cellulose acetate solution (parts by mass): Inner layer, Outer layer ―――――――――――――――――――――――――――――――― Cellulose acetate with a degree of acetylation of 60.9% 100 100 Triphenyl phosphate (plasticizer) 7.8 7.8 Biphenyl diphenyl phosphate (plasticizer) 3.9 3.9 Dichloromethane (first solvent) 293 314 Methanol (second solvent) 71 76 1-Butanol (third solvent) 1.5 1.6 Silica microparticles (AEROSIL R972, manufactured by Evonik Japan Co., Ltd.) 0 0.8 The following delay enhancer 1.7 0 ―――――――――――――――――――――――――――――――― [Chemical Formula 13] Using a three-layer co-casting die, the inner and outer layer dopant solutions were cast on a roller cooled to 0°C. A film with 70% by mass of residual solvent was peeled off from the roller, fixed at both ends using a pin-plate tenter frame, and dried at 80°C while being fed at a stretch ratio of 110% in the stretching direction. When the residual solvent content reached 10%, it was dried at 110°C. Subsequently, the obtained film was dried at 140°C for 30 minutes to fabricate a transparent support 1 for a cellulose acetate film (80 μm thick (outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) with 0.3% by mass of residual solvent. The fabricated cellulose acetate film had an in-plane retardation Re of 5 nm at 550 nm and a thickness retardation Rth of 90 nm at 550 nm.

[0266] The prepared cellulose acetate was immersed in a 2.0N potassium hydroxide solution (25°C) for 2 minutes, then neutralized with sulfuric acid, washed with pure water, and dried.

[0267] (Fabrication of Orientation Film 3) Using a #16 bar coater, at 28 mL / m 2 The coating solution with the following composition was applied onto the cellulose acetate membrane. The resulting coating was dried with hot air at 60°C for 60 seconds, and then further dried with hot air at 90°C for 150 seconds. An alignment film 3 was produced by rubbing the surface of the formed coating with a friction roller at 500 rpm in a direction parallel to the conveying direction.

[0268] ─────────────────────────────── (Composition of the coating solution for orientation film 3) ─────────────────────────────── 10 parts by weight of the following modified polyvinyl alcohol 370 parts by weight of water 120 parts by weight of methanol Glutaraldehyde (crosslinking agent) 0.5 parts by weight ─────────────────────────────── [Chemical Formula 14] (Fabrication of the hybrid orientation layer) Using a #3.2 wire rod, the following coating solution was continuously applied to the alignment film 3 surface of the film. In a process of continuously heating from room temperature to 100°C, after drying the solvent, the film was heated in a drying zone at 135°C for approximately 90 seconds to align the disc-shaped liquid crystal compound. Next, it was transferred to a drying zone at 80°C, and with the film surface temperature at approximately 100°C, it was irradiated with 600mW ultraviolet light for 10 seconds to induce a crosslinking reaction, polymerizing the disc-shaped liquid crystal compound. Afterward, it was cooled to room temperature to produce a mixed alignment layer.

[0269] The results of measuring the optical film containing the hybrid alignment layer described above were obtained using the method described above, and it was confirmed that the angle with the smallest phase difference was not 0°.

[0270] The measurement results show that the in-plane retardation at a wavelength of 550 nm, measured from the normal direction of the mixed alignment layer, is 30 nm, and the tilt angle (the average tilt angle between the optical axis of the disk-shaped liquid crystal compound and the surface of the mixed alignment layer) is 15°.

[0271] ―――――――――――――――――――――――――――――――――― (Composition of the mixed orientation layer coating liquid) ―――――――――――――――――――――――――――――――――― 98 parts by weight of methyl ethyl ketone The following disk-shaped liquid crystal compound (1) 41.01 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 parts by weight cellulose acetate butyl ester (CAB551-0.2, manufactured by Eastman Chemical Company) 0.34 parts by weight cellulose acetate butyl ester (CAB531-1, manufactured by Eastman Chemical Company) 0.11 parts by weight 0.13 parts by weight of the following fluorinated aliphatic polymer The following fluorinated aliphatic polymer 2 0.03 parts by weight Photopolymerization initiator (Irgacure 907, manufactured by Ciba-Geigy Japan Limited) 1.35 parts by weight Sensitizer (KAYACURE DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by weight ―――――――――――――――――――――――――――――――――― Disc-shaped liquid crystal compounds (1) [Chemical Formula 15] Fluorinated aliphatic polymer 1 (a / b / c=20 / 20 / 60 wt%) [Chemical Formula 16] 2. Fluorinated aliphatic polymer (a / b=98 / 2 wt%) [Chemical Formula 17] (The fabrication of image display device 3 with viewing angle opening and closing function) A mixed alignment layer (mixed alignment layer-1, mixed alignment layer-2) is used instead of a tilted alignment layer A. The azimuth angle when the direction of the optical axis of the liquid crystal compound in mixed alignment layer-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of mixed alignment layer-1 is 180°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound in mixed alignment layer-2 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of mixed alignment layer-2 is 180°. Otherwise, an image display device 3 with viewing angle opening and closing function is manufactured in the same manner as in Example 1.

[0272] <Example 4> (The creation of the view control system 4) In the fabrication of the viewing angle control system 3 in Example 3, the azimuth angle when the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the mixed alignment layer-1 is 90°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-2 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the mixed alignment layer-2 is 270°. Otherwise, the viewing angle control system 4 with the structure of polarizer-1 / mixed alignment layer-1 / TN liquid crystal cell-1 / polarizer-2 / TN liquid crystal cell-2 / mixed alignment layer-2 / polarizer-3 is fabricated in the same manner as in Example 3.

[0273] (The fabrication of image display device 4 with viewing angle opening and closing function) In the manufacture of the image display device 1 with viewing angle opening and closing function in Embodiment 1, the viewing angle control system 1 was changed to the viewing angle control system 4. Otherwise, the image display device 4 was manufactured in the same manner as in Embodiment 1.

[0274] <Example 5> (The creation of the view control system 5) Using a commercially available adhesive (manufactured by Sangyo Fine Chemical Co., Ltd., SK2057), the above-prepared hybrid alignment layer, the above-prepared polarizer, and the above-prepared TN liquid crystal cell were bonded together to create a viewing angle control system 5 that is polarizer (polarizer-1) / hybrid alignment layer (hybrid alignment layer-1) / TN liquid crystal cell (TN liquid crystal cell-1) / hybrid alignment layer (hybrid alignment layer-3) / polarizer (polarizer-2) / hybrid alignment layer (hybrid alignment layer-2) / TN liquid crystal cell (TN liquid crystal cell-2) / hybrid alignment layer (hybrid alignment layer-4) / polarizer (polarizer-3).

[0275] Alternatively, the name in parentheses above can be used in the latter part.

[0276] At this point, the absorption axes of polarizer-1 and polarizer-3 are aligned at an azimuth angle of 90°, and the absorption axis of polarizer-2 is aligned at an azimuth angle of 0°. That is, the transmission axes of polarizer-1 and polarizer-3 are aligned at an azimuth angle of 0°, and the transmission axis of polarizer-2 is aligned at an azimuth angle of 90°.

[0277] Furthermore, the azimuth angle when projecting the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-1 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) onto the surface of the mixed alignment layer-1 is 90°, the azimuth angle when projecting the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-2 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) onto the surface of the mixed alignment layer-2 is 270°, the azimuth angle when projecting the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-3 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) onto the surface of the mixed alignment layer-3 is 90°, and the azimuth angle when projecting the direction of the optical axis of the liquid crystal compound in the mixed alignment layer-4 (from the front end of the optical axis on the polarizer-3 side to the front end of the polarizer-1 side) onto the surface of the mixed alignment layer-4 is 270°.

[0278] Furthermore, the azimuth angle when the direction of the optical axis of the liquid crystal compound on the mixed alignment layer-1 side in the liquid crystal layer of the TN liquid crystal cell-1 (from the front end of the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the mixed alignment layer-3 is 180°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound on the mixed alignment layer-3 side in the liquid crystal layer of the TN liquid crystal cell-1 (from the front end of the polarizer-3 side to the front end of the polarizer-1 side) is projected onto the surface of the mixed alignment layer-3 is 90°.

[0279] Furthermore, the azimuth angle when the direction of the optical axis of the liquid crystal compound on the mixed alignment layer-4 side in the liquid crystal layer of the TN liquid crystal cell-2 (from the front end on the polarizer-3 side to the front end on the polarizer-1 side) is projected onto the surface of the mixed alignment layer-2 is 270°, and the azimuth angle when the direction of the optical axis of the liquid crystal compound on the mixed alignment layer-2 side in the liquid crystal layer of the TN liquid crystal cell-2 (from the front end on the polarizer-3 side to the front end on the polarizer-1 side) is projected onto the surface of the mixed alignment layer-2 is 180°.

[0280] (The creation of image display system 5 with viewing angle opening and closing function) In the manufacture of the image display device 1 with viewing angle opening and closing function in Embodiment 1, the viewing angle control system 1 was changed to the viewing angle control system 5. Otherwise, the image display device 5 was manufactured in the same manner as in Embodiment 1.

[0281] <Comparative Example 1> (The creation of the view control system B1) In the fabrication of the viewing angle control system 1 in Example 1, without attaching the tilted alignment layer A, a viewing angle control system B1 was fabricated that consists of a polarizer (polarizer-1) / TN liquid crystal cell (TN liquid crystal cell-1) / polarizer (polarizer-2) / TN liquid crystal cell (TN liquid crystal cell-2) / polarizer (polarizer-3).

[0282] (The fabrication of image display device B1 with viewing angle opening and closing function) In the manufacture of the image display device 1 with viewing angle opening and closing function in Embodiment 1, the viewing angle control system 1 was changed to the viewing angle control system B1. Otherwise, the image display device B1 was manufactured in the same manner as in Embodiment 1.

[0283] <Comparative Example 2> (Fabrication of negative A-layer (non-tilted orientation layer)) The alignment film 3 prepared above was continuously subjected to a friction treatment. Next, a negative A-plate coating solution containing a disk-shaped liquid crystal compound with the following composition was continuously coated onto the alignment film 3 using a #5.0 wire rod to form a coating. The film transport speed (V) was set to 26 m / min. To dry the solvent of the coating solution and to ripen the orientation of the disk-shaped liquid crystal compound, it was heated with hot air at 130°C for 90 seconds, followed by heating with hot air at 100°C for 60 seconds, and then irradiated with UV at 80°C to fix the orientation of the liquid crystal compound, thus forming a negative A-plate. The thickness of the negative A-plate was 0.8 μm, and the in-plane retardation at a wavelength of 550 nm was 110 nm.

[0284] It was confirmed that the average tilt angle of the disk surface of the disk-shaped liquid crystal compound relative to the thin film surface is 90°, and the disk-shaped liquid crystal compound is vertically oriented relative to the thin film surface.

[0285] ――――――――――――――――――――――――――――― Composition of the coating liquid for negative A plate layer ――――――――――――――――――――――――――――― • The following disc-shaped liquid crystal - 80 parts by weight • The following disc-shaped liquid crystal - 20 parts by weight • 0.55 parts by weight of the following orientation film interface alignment agent-1 • 0.05 parts by weight of the following orientation film interface alignment agent-2 • 0.09 parts by weight of the following surfactant F-4 10 parts by weight of modified trimethylolpropane triacrylate • Photopolymerization initiator (Irgacure 907, manufactured by BASF) 3.0 parts by weight 200 parts by weight of methyl ethyl ketone ――――――――――――――――――――――――――――― Disc-shaped LCD-1 [Chemical Formula 18] Disc-shaped LCD-2 [Chemical Formula 19] Orientation film interface orientation agent-1 [Chemical Formula 20] Orientation agent-2 for orientation film interface [Chemical Formula 21] Surfactant F-4 [Chemical Formula 22] (The creation of the B2 view control system) In the fabrication of the viewing angle control system 1 in Example 1, the tilted alignment layer A was changed to a negative A plate layer. Otherwise, a viewing angle control system B2 was fabricated in the same manner, consisting of a polarizer (polarizer-1) / negative A plate layer (negative A plate layer-1) / TN liquid crystal cell (TN liquid crystal cell-1) / polarizer (polarizer-2) / TN liquid crystal cell (TN liquid crystal cell-2) / negative A plate layer (negative A plate layer-2) / polarizer (polarizer-3). At this time, the azimuth angle of the optical axes of the negative A plate layer-1 and negative A plate layer-2 is 0°.

[0286] (The fabrication of image display device B2 with viewing angle opening and closing function) In the manufacture of the image display device 1 with viewing angle opening and closing function in Embodiment 1, the viewing angle control system 1 was changed to the viewing angle control system B2. Otherwise, the image display device B2 was manufactured in the same manner as in Embodiment 1.

[0287] <Evaluation of the View Control Device> The following evaluation was conducted on the image display device with viewing angle opening and closing function that was produced.

[0288] (1) Light leakage in the tilt direction Image recognition when viewing an image display device in a mode with a reduced viewing angle (privacy mode) from a horizontal or obliquely upward perspective was compared with that of image display device B1 (Comparative Example 1), and evaluated according to the following criteria. The results are shown in Table 1 below. Preferably, C or higher.

[0289] (Evaluation criteria) A+: The image cannot be recognized when viewed horizontally or diagonally from above.

[0290] A: The displayed image cannot be recognized when viewed horizontally.

[0291] B: Compared to the image display device B1, the displayed image is difficult to identify when viewed from the side.

[0292] C: Compared to the image display device B1, the displayed image is slightly more difficult to recognize when viewed from the side.

[0293] D: Capable of recognizing display images of the same quality as those displayed by image display device B1.

[0294] (2) Brightness in the front direction The brightness of the image display device viewed from the front in a mode with a narrowed viewing angle (privacy mode) was compared with that of the image display device B1 (Comparative Example 1), and the following criteria were used for evaluation.

[0295] (Evaluation criteria) A: The difference in brightness cannot be discerned compared to the image display device B1.

[0296] B: It feels darker compared to the image display device B1.

[0297] The values ​​in parentheses in the “Structure” column of Table 1 represent azimuth angles.

[0298] In Table 1, the "tilt angle" column indicates the angle (polar angle) of the normal direction where the phase difference is smallest in the optical compensation layer used.

[0299] In Table 1, the "Angle" column indicates the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer in the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer, and the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer in the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer.

[0300] As shown in Table 1, the desired effect of the perspective control system of the present invention is confirmed.

[0301] A comparison of Examples 1 and 2 confirms that using a disc-shaped liquid crystal compound as the material for the optical compensation layer yields superior results.

[0302] A comparison of Examples 3 and 4 confirms that the effect is superior when the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer in the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the first optical compensation layer side is 45 to 135°, and the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer in the second optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the second optical compensation layer side is 45 to 135°.

[0303] Based on a comparison of Embodiment 5 with other embodiments, it was confirmed that the effect is better when using the third optical compensation layer and the fourth optical compensation layer.

[0304] Symbol Explanation 10 - First polarizer, 12 - First optical compensation layer, 14 - First liquid crystal cell, 16 - Second polarizer, 18 - Second liquid crystal cell, 20, 20A - Second optical compensation layer, 22 - Third polarizer, 24, 30 - Liquid crystal layer, 26, 28, 32, 34 - Substrate, 40 - Third optical compensation layer, 42 - Fourth optical compensation layer.

Claims

1. A perspective control system, comprising, in sequence: First polarizer; First optical compensation layer; First liquid crystal unit; Second polarizer; Second liquid crystal unit; Second optical compensation layer; and The third polarizer The first liquid crystal unit and the second liquid crystal unit are TN mode liquid crystal units. For the first optical compensation layer, when measuring the phase difference from the normal direction of the first optical compensation layer and from the direction inclined from the normal direction of the first optical compensation layer, it is the layer with the smallest phase difference in the direction inclined from the normal direction of the first optical compensation layer. For the second optical compensation layer, when measuring the phase difference from the normal direction of the second optical compensation layer and the direction inclined from the normal direction of the second optical compensation layer, it is the layer with the smallest phase difference in the direction inclined from the normal direction of the second optical compensation layer.

2. The view control system according to claim 1, wherein, The first optical compensation layer and the second optical compensation layer are layers formed by fixing liquid crystal compounds with tilted or mixed orientations.

3. The view control system according to claim 2, wherein, The liquid crystal compound is a disc-shaped liquid crystal compound or a rod-shaped liquid crystal compound.

4. The view control system according to claim 2, wherein, In the first optical compensation layer, the angle between the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the first optical compensation layer and the in-plane slow axis on the surface of the liquid crystal layer in the first liquid crystal cell on the side of the first optical compensation layer is 45° to 135°. In the second optical compensation layer, the projection axis formed by projecting the optical axis of the liquid crystal compound onto the surface of the second optical compensation layer forms an angle of 45° to 135° with the in-plane slow axis on the surface of the liquid crystal layer in the second liquid crystal cell on the side of the second optical compensation layer.

5. The view control system according to claim 1, wherein, A third optical compensation layer is further provided between the first liquid crystal cell and the second polarizer. A fourth optical compensation layer is further provided between the second polarizer and the second liquid crystal cell. For the third optical compensation layer, when measuring the phase difference from the normal direction of the third optical compensation layer and in the direction inclined from the normal direction of the third optical compensation layer, it is the layer with the smallest phase difference in the direction inclined from the normal direction of the third optical compensation layer. For the fourth optical compensation layer, when measuring the phase difference from the normal direction of the fourth optical compensation layer and the direction inclined from the normal direction of the fourth optical compensation layer, it is the layer with the smallest phase difference in the direction inclined from the normal direction of the fourth optical compensation layer.

6. An image display device comprising an image display element and a viewing angle control system according to any one of claims 1 to 5.

Images