Optical film, phase difference plate, image display panel, and image display device

Abstract

To provide an optical film that minimizes the difference in appearance depending on the viewing direction. [Solution] The optical film 1 is an optical film comprising a liquid crystal layer 10. When observed from the thickness direction dn of the optical film 1, the optical film 1 includes a plurality of pattern regions 20 arranged in a first direction d1 perpendicular to the thickness direction dn. The plurality of pattern regions 20 include a plurality of first regions 21 and a plurality of second regions 22, and the plurality of first regions 21 and the plurality of second regions 22 are arranged alternately in the first direction d1. The angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is 80° or more and 100° or less. The width of each of the plurality of first regions 21 and the plurality of second regions 22 in the first direction d1 is 45 μm or more and 240 μm or less. The plurality of pattern regions 20 further include gap regions 23 provided between each of the plurality of first regions 21 and the plurality of second regions 22.

Description

Technical Field

[0001] The present disclosure relates to an optical film, a retardation plate, an image display panel, and an image display device.

Background Art

[0002] Conventionally, an optical film including a retardation layer that imparts a desired retardation to incident light by the retardation layer is known and is applied to a display device that displays an image or the like. As an example, in a display device, it is known to use a retardation plate including a quarter-wave plate (a retardation layer having a retardation of 1 / 4 wavelength for birefringent light) and a linear polarizer for the purpose of antireflection of the display device. In particular, Non-Patent Document 1 discloses a circular polarizer including a quarter-wave plate and a linear polarizer as a retardation plate. In the circular polarizer of Non-Patent Document 1, the quarter-wave plate includes two types of domains: a first domain in which the direction of the slow axis forms an angle of 45° with respect to the direction of the absorption axis of the linear polarizer, and a second domain in which the direction of the slow axis forms an angle of -45° with respect to the direction of the absorption axis of the linear polarizer. Further, Non-Patent Document 1 discloses that the reflectance is suppressed to be small by the circular polarizer, and the change in color according to the observed azimuth angle of the circular polarizer is suppressed to be small.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In optical films equipped with a phase difference layer, the appearance of the optical film may differ depending on the direction in which it is observed. Accordingly, the appearance of the phase difference plate in which the optical film is incorporated may also differ depending on the direction in which the optical film is observed. In particular, Non-Patent Document 1, mentioned above, confirms through simulation tests that in a circular polarizer containing two types of domains, the color change depending on the azimuth angle in which the circular polarizer is observed can be kept to a minimum. On the other hand, Non-Patent Document 1 does not include performance testing of actually manufactured circular polarizers. Therefore, there is a need for a means to minimize the difference in appearance depending on the direction in which the optical film is observed in optical films equipped with a phase difference layer that are actually manufactured.

[0005] This disclosure has been made in consideration of the above points, and aims to provide an optical film in which the difference in appearance depending on the viewing direction of the optical film is kept to a minimum. [Means for solving the problem]

[0006] Embodiments of this disclosure relate to the following [1] to

[11] .

[0007] [1] An optical film comprising a liquid crystal layer, The optical film, when observed from the thickness direction of the optical film, includes a plurality of pattern regions aligned in a first direction perpendicular to the thickness direction, The plurality of pattern regions include a plurality of first regions and a plurality of second regions, and the plurality of first regions and the plurality of second regions are arranged alternately in the first direction. The angular difference between the direction of the phase-lagging axis of the liquid crystal layer in the first region and the direction of the phase-lagging axis of the liquid crystal layer in the second region is 80° or more and 100° or less. The width of each of the plurality of first regions and the plurality of second regions in the first direction is 45 μm or more and 240 μm or less. An optical film in which the plurality of pattern regions further include gap regions provided between each of the plurality of first regions and the plurality of second regions.

[0008] [2] In the first region, the direction of the phase-lagging axis of the liquid crystal layer is at an angle of 45° with respect to the first direction. In the second region, the direction of the phase-lagging axis of the liquid crystal layer is at an angle of -45° with respect to the first direction, the optical film according to [1].

[0009] [3] The optical film according to [1] or [2], wherein the width of the gap region in the first direction is 140 nm or more and 4000 nm or less.

[0010] [4] Further equipped with an orientation layer, The optical film according to any one of [1] to [3], wherein the liquid crystal layer is laminated on the alignment layer.

[0011] [5] The optical film according to [4], wherein at least an uneven shape is formed on the surface of the alignment layer on which the liquid crystal layer is laminated.

[0012] [6] The optical film according to [4], wherein the orientation layer comprises a component having a functional group that produces photoreactivity.

[0013] [7] [1] An optical film described in any one of [1] or [6], A phase difference plate comprising: a polarizing plate superimposed on the optical film such that the angle the absorption axis makes with respect to the first direction is 0°±5° or 90°±5°; and a phase difference plate.

[0014] [8] An image display panel comprising the phase difference plate described in [7].

[0015] [9] The panel itself is further equipped, The retardation plate is disposed on the panel body, The image display panel according to [8], wherein the distance between the liquid crystal layer and the panel body is 1 μm or more and 120 μm or less.

[0016]

[10] An image display device comprising the retardation plate according to [7].

[0017]

[11] Further comprising a panel body, The retardation plate is disposed on the panel body, The image display device according to

[10] , wherein the distance between the liquid crystal layer and the panel body is 1 μm or more and 120 μm or less.

Advantages of the Invention

[0018] According to an embodiment of the present disclosure, an optical film can be provided in which the difference in appearance depending on the viewing direction of the optical film is suppressed to be small.

Brief Description of the Drawings

[0019] [Figure 1A] FIG. 1A is a cross-sectional view showing an optical film according to an embodiment. T [Figure 1B] FIG. 1B is a cross-sectional view showing an optical film according to an embodiment. [Figure 2] FIG. 2 is a plan view showing an optical film according to an embodiment. [Figure 3A] FIG. 3A is a cross-sectional view showing an alignment layer according to an embodiment. [Figure 3B] FIG. 3B is a schematic view showing an exposure apparatus for producing the alignment layer. [Figure 4] FIG. 4 is a cross-sectional view showing a retardation plate according to an embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing an image display device according to an embodiment. [Figure 6A] FIG. 6A is a diagram for explaining a representation method of an observation direction of an optical member. [Figure 6B]Figure 6B is a diagram illustrating how to represent the observation direction of an optical component. [Figure 7A] Figure 7A is a diagram illustrating the effect of optical film. [Figure 7B] Figure 7B is a diagram illustrating the effect of optical film. [Figure 7C] Figure 7C is a diagram illustrating the effect of optical film. [Figure 8] Figure 8 is a plan view showing an optical film according to Modification 1. [Figure 9] Figure 9 is a plan view showing an optical film according to Modification 2. [Figure 10] Figure 10 is a plan view showing an optical film according to Modification 2. [Figure 11] Figure 11 is a plan view showing an optical film according to Modification 3. [Figure 12] Figure 12 is a plan view showing an optical film according to Modification 4. [Figure 13] Figure 13 is a graph showing the results of the brightness evaluation test. [Figure 14A] Figure 14A is an image of the surface of the liquid crystal layer taken during the surface observation and evaluation test of the optical film in Example 3. [Figure 14B] Figure 14B shows an image of the surface of the liquid crystal layer taken during the surface observation and evaluation test of the optical film in Comparative Example 3. [Modes for carrying out the invention]

[0020] The following describes in detail one embodiment of the present disclosure. In the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of illustration and ease of understanding. Components shown in some drawings may be omitted in other drawings. The scale and aspect ratios may differ between drawings.

[0021] In this specification, terms such as "film," "sheet," and "plate" are not distinguished from each other solely on the basis of differences in name. For example, "optical film" cannot be distinguished from components called optical sheets or optical plates solely on the basis of differences in name.

[0022] In this specification, the thickness direction of a film-like (sheet-like, plate-like) member refers to the direction parallel to the normal or perpendicular to the film surface (sheet surface, plate surface) of the film-like (sheet-like, plate-like) member in question. The "film surface (sheet surface, plate surface)" refers to the surface that coincides with the film-like (sheet-like, plate-like) member in question when viewed as a whole and in a broad sense.

[0023] In this specification, multiple candidate upper limits and multiple candidate lower limits for a numerical range may be described in separate statements. In such statements, the numerical range may be constructed by combining any one candidate upper limit and any one candidate lower limit. As an example, consider the statement, "Parameter B may be greater than or equal to A1, greater than or equal to A2, greater than or equal to A3. Parameter B may be less than or equal to A4, less than or equal to A5, or less than or equal to A6." In this example, the numerical range of parameter B may be greater than or equal to A1 and less than or equal to A4, greater than or equal to A1 and less than or equal to A5, greater than or equal to A1 and less than or equal to A6, greater than or equal to A2 and less than or equal to A4, greater than or equal to A2 and less than or equal to A5, greater than or equal to A2 and less than or equal to A6, greater than or equal to A3 and less than or equal to A4, greater than or equal to A3 and less than or equal to A5, or greater than or equal to A6.

[0024] To clarify directional relationships between drawings, some drawings use arrows with common symbols to indicate common directions, such as "first direction d1" described later. Arrows pointing towards the viewer along the direction perpendicular to the plane of the drawing are indicated by a symbol of a dot inside a circle, as shown in Figure 1A, for example.

[0025] Figure 1A is a cross-sectional view showing an example of the optical film 1 of this embodiment. Figure 1B is a cross-sectional view showing another example of the optical film 1 of this embodiment, different from that shown in Figure 1A. As shown in Figures 1A and 1B, the optical film 1 of this embodiment comprises a liquid crystal layer 10. The optical film 1 shown in Figures 1A and 1B further comprises an alignment layer 50. The liquid crystal layer 10 is laminated on the alignment layer 50.

[0026] The optical film 1 has a first surface 1a and a second surface 1b located on the opposite side of the first surface 1a. In the optical film 1 with an alignment layer 50 as shown in Figures 1A and 1B, the first surface 1a is a surface whose distance from the liquid crystal layer 10 is smaller than the distance from the alignment layer 50. In the example shown in Figure 1A, the first surface 1a is composed of the alignment layer 50. In the optical film 1 with an alignment layer 50 as shown in Figures 1A and 1B, the second surface 1b is a surface whose distance from the alignment layer 50 is smaller than the distance from the liquid crystal layer 10. In the example shown in Figure 1A, the second surface 1b is composed of the alignment layer 50. In the example shown in Figure 1A, the alignment layer 50 and the liquid crystal layer 10 are laminated in this order from the second surface 1b toward the first surface 1a. The optical film 1 shown in Figure 1B further includes a substrate layer 40. In this case, the alignment layer 50 may be laminated on the substrate layer 40. If the optical film 1 includes a base layer 40, the first surface 1a may be composed of the base layer 40, as shown in Figure 1B.

[0027] Figure 2 shows a portion of the optical film 1 of this embodiment as observed from the thickness direction dn of the optical film 1. The straight lines in the pattern region 20, described later, in Figure 2 indicate the orientation direction of the liquid crystal compounds in the liquid crystal layer 10. The direction in which liquid crystal compounds are oriented in a liquid crystal layer such as the liquid crystal layer 10 is also called the orientation direction. Unless otherwise specified, the orientation direction of the liquid crystal compounds is the orientation direction of the liquid crystal compounds in the direction perpendicular to the thickness direction dn when the optical film 1 is observed from the thickness direction dn. In this embodiment, the liquid crystal compounds contained in the liquid crystal layer 10 are oriented in the direction perpendicular to the thickness direction dn. The orientation direction of the liquid crystal compounds in the liquid crystal layer 10 is the direction of the slow axis of the liquid crystal layer 10. In this embodiment, the direction of the slow axis of the liquid crystal layer 10 is the direction perpendicular to the thickness direction dn, which is observed as the direction in which the slow axis extends when the optical film 1 is observed from the thickness direction dn. For the sake of simplifying the drawing, Figure 2 avoids precisely illustrating the orientation direction of the liquid crystal compound in the liquid crystal layer 10 of a practical optical film 1, and instead shows a more simplified orientation direction of the liquid crystal compound.

[0028] As shown in Figure 2, the optical film 1 of this embodiment includes a plurality of pattern regions 20 arranged in a first direction d1 perpendicular to the thickness direction dn when observed from the thickness direction dn of the optical film 1. The optical film 1 further includes gap regions 23 provided between each of the plurality of pattern regions 20.

[0029] The first direction d1, which is the direction in which multiple pattern regions 20 are aligned, is defined as follows: The centroid GC1 is the centroid of the shape of the first region 21 when observed from the thickness direction dn of the optical film 1. The centroid GC2 is the centroid of the shape of the second region 22 when observed from the thickness direction dn of the optical film 1. From the directions perpendicular to the thickness direction dn in which centroids GC1 and GC2 are aligned, the direction in which the width of the gap region 23 is minimized is identified. The direction identified in this way is defined as the first direction d1.

[0030] Each of the multiple pattern regions 20 includes at least one first region 21 and at least one second region 22. The multiple pattern regions 20 may also include a single first region 21. The multiple pattern regions 20 may also include a single second region 22. In the example shown in Figure 2, the multiple pattern regions 20 include multiple first regions 21 and multiple second regions 22. The optical film 1 can function even if either or both of the first region 21 and the second region 22 are singular. However, by including multiple first regions 21 and second regions 22, the optical film 1 can minimize the difference in appearance of the optical film 1 depending on the viewing direction, as will be described later. From this viewpoint, it is preferable that the optical film 1 includes multiple first regions 21 and second regions 22. The multiple first regions 21 and the multiple second regions 22 are arranged alternately in the first direction d1. In other words, in the first direction d1, the pattern in which the first region 21 and the second region 22 are arranged in this order is repeated. Each of the multiple pattern regions 20 further includes a gap region 23 provided between each of the multiple first regions 21 and the multiple second regions 22. The gap region 23 is provided between each of the multiple first regions 21 and the multiple second regions 22 in the first direction d1. In other words, in the first direction d1, the pattern in which the first region 21, gap region 23, second region 22 and gap region 23 are arranged in this order is repeated. The distance p1 between the centroid GC1 of adjacent first regions 21 and the centroid GC2 of adjacent second regions 22 in the first direction d1 shown in Figure 2 is also called the pitch p1 of the pattern region 20.

[0031] The angular difference between the direction of the phase-lagging axis of the liquid crystal layer 10 in the first region 21 and the direction of the phase-lagging axis of the liquid crystal layer 10 in the second region 22 is between 80° and 100°. That is, the angular difference between the direction of the phase-lagging axis of the liquid crystal layer 10 in the first region 21 and the direction of the phase-lagging axis of the liquid crystal layer 10 in the second region 22 is within the range of ±10° with respect to 90°. The "angular difference between the direction of the phase-lagging axis of the liquid crystal layer 10 in the first region 21 and the direction of the phase-lagging axis of the liquid crystal layer 10 in the second region 22" is a value expressed as a positive number, representing the angle between the direction of the phase-lagging axis of the liquid crystal layer 10 in the first region 21 and the direction of the phase-lagging axis of the liquid crystal layer 10 in the second region 22. By definition, the "angular difference between the direction of the phase-lagging axis of the liquid crystal layer 10 in the first region 21 and the direction of the phase-lagging axis of the liquid crystal layer 10 in the second region 22" cannot be a negative number.

[0032] In this embodiment, in the first region 21, the direction of the slow axis of the liquid crystal layer 10 is at an angle of 45° with respect to the first direction d1. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 is at an angle of -45° with respect to the first direction d1. That is, if a virtual line segment extending in the first direction d1 is rotated by 45° in one direction, that line segment becomes parallel to the direction in which the slow axis of the liquid crystal layer 10 extends in the first region 21. Furthermore, if the virtual line segment extending in the first direction d1 is rotated by 45° in the opposite direction to the above-mentioned one direction, that line segment becomes parallel to the direction in which the slow axis of the liquid crystal layer 10 extends in the second region 22. Thus, the direction in which the slow axis of the liquid crystal layer 10 extends in the first region 21 and the direction in which the slow axis of the liquid crystal layer 10 extends in the second region 22 are orthogonal.

[0033] The range of the first region 21 can be identified as the range in which the direction of the slow axis of the liquid crystal layer 10 is oriented in one direction when the optical film 1 is observed from the thickness direction dn. The range of the second region 22 can be identified as the range in which the direction of the slow axis of the liquid crystal layer 10 is oriented in one direction such that the angular difference between it and the direction of the slow axis of the liquid crystal layer 10 in the first region 21 is 80° or more and 100° or less. In this embodiment, in the first region 21, the direction of the slow axis of the liquid crystal layer 10 is at an angle of 45° with respect to the first direction d1. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 is at an angle of -45° with respect to the first direction d1. In this case, the range of the first region 21 can be identified as the range in which the direction of the slow axis of the liquid crystal layer 10 is at an angle of 45° with respect to the first direction d1 when the optical film 1 is observed from the thickness direction dn. The range of the second region 22 can be identified as the range in which, when the optical film 1 is observed from the thickness direction dn, the direction of the slow axis of the liquid crystal layer 10 forms an angle of -45° with respect to the first direction d1.

[0034] In the example shown in Figure 2, the multiple first regions 21 are not connected to each other. In the example shown in Figure 2, the second regions 22 and the gap regions 23 are located between the multiple first regions 21. For this reason, the multiple first regions 21 are not connected to each other. In the example shown in Figure 2, the multiple second regions 22 are not connected to each other. In the example shown in Figure 2, the first regions 21 and the gap regions 23 are located between the multiple second regions 22. For this reason, the multiple second regions 22 are not connected to each other.

[0035] Although not shown in the figures, the optical film 1 may include a first connection region when observed from the thickness direction dn. The direction of the slow axis of the liquid crystal layer 10 in the first connection region may be the same as the direction of the slow axis of the liquid crystal layer 10 in the first region 21. Multiple first regions 21 may be connected to each other via the first connection region. Although not shown in the figures, the optical film 1 may include a second connection region when observed from the thickness direction dn. The direction of the slow axis of the liquid crystal layer 10 in the second connection region may be the same as the direction of the slow axis of the liquid crystal layer 10 in the second region 22. Multiple second regions 22 may be connected to each other via the second connection region. Thus, even when the optical film 1 has a first connection region and a second connection region, if the first region 21 and the second region 22 are arranged alternately in the first direction d1, it can be considered that there are multiple first regions 21 and multiple second regions 22.

[0036] Although not shown in the figures, the optical film 1 may include regions where, when observed from the thickness direction dn, the direction of the slow axis of the liquid crystal layer 10 differs from the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the second region 22. The optical film 1 may include regions where the direction of the slow axis of the liquid crystal layer 10 differs from that of the first region 21 and the second region 22, as long as this does not significantly hinder the performance of the effects of the first region 21 and the second region 22.

[0037] <Base material layer> The substrate layer 40 may support the alignment layer 50 and the liquid crystal layer 10. The substrate layer 40 may protect the alignment layer 50 and the liquid crystal layer 10. The substrate layer 40 may have optical isotropy. The substrate layer 40 may include a layer made of polymer. The substrate layer 40 may include a layer made of glass.

[0038] Examples of polymers included in the base layer 40 include cellulose acylate, polycarbonate polymers, polyester polymers such as polyethylene terephthalate or polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, or styrene polymers such as polystyrene or acrylonitrile-styrene copolymer (AS resin). Examples of polymers constituting the base layer 40 include polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon or aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, or mixtures of these polymers. The base layer 40 may also be a uniaxially oriented PET film. In this case, CosmoShine SRF® manufactured by Toyobo Co., Ltd. may be used as the base layer 40.

[0039] In particular, in the optical film 1 intended to affect visible light, the in-plane phase difference of the substrate layer 40 with respect to 552.1 nm light may be 20 nm or less, 5 nm or less, 3 nm or less, 1 nm or less, or 0 nm. Since the in-plane phase difference of the substrate layer 40 is very small, the measurement device may be a KOBRA-WR manufactured by Oji Instruments Co., Ltd., and the measurement may be performed in low phase difference mode.

[0040] The thickness of the polymer-containing substrate layer 40 may be between 10 μm and 125 μm. The thickness of the glass-containing substrate layer 40 may be between 100 μm and 5 mm.

[0041] The base layer 40 may be a release substrate that can be peeled off from the alignment layer 50 and the liquid crystal layer 10. This allows the base layer 40 to be peeled off from the alignment layer 50 and the liquid crystal layer 10 after the surface of the optical film 1 that is not covered by the base layer 40 has been attached to the other component when attaching the optical film 1 to another component. For example, when manufacturing a phase difference plate 60 using the optical film 1 as described later, the base layer 40 can be peeled off from the alignment layer 50 and the liquid crystal layer 10 after the optical film 1 and the polarizing plate 61 described later have been bonded together.

[0042] <Oriented layer> The alignment layer 50 plays a role in facilitating the orientation of liquid crystal compounds within the liquid crystal layer 10 during its formation. In other words, the alignment layer 50 has an orientation-regulating force that aligns the liquid crystal compounds contained in the liquid crystal layer 10. The surface of the alignment layer 50 on which the liquid crystal layer 10 is laminated is referred to as the alignment surface 50b.

[0043] Conventional known methods can be used as means to impart orientation-restricting force to the orientation layer 50. For example, means to impart orientation-restricting force to the orientation layer 50 include the imprint method, the rubbing method, or the photo-orientation method. When the orientation layer 50 is produced by the imprint method, an ionizing radiation-curable resin can be used to prevent deformation of the shape after curing. Ionizing radiation-curable resins include UV-curable resins and EB-curable resins. In particular, when the orientation layer 50 is produced by the imprint method, the orientation layer 50 may contain a UV-curable resin. That is, the resin composition for forming the orientation layer 50 may be a UV-curable resin. Specific examples of UV-curable resins include materials to which a photopolymerization initiator and optional additives have been added, such as polymerizable oligomers or monomers having acryloyl groups, such as urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, and melamine acrylate, and polymerizable oligomers or monomers having polymerizable vinyl groups, such as acrylic acid, acrylamide, acrylonitrile, and styrene, either individually or in combination. The material of the orientation layer 50 may be, for example, a thermosetting resin. When the orientation layer 50 is produced by the photo-orientation method, first, the solvent is removed by drying the solution containing the thermosetting resin. Then, using a mask having a shape corresponding to the uneven shape 51 of the orientation surface 50b, intramolecular or intermolecular dimerization or isomerization is performed by ultraviolet irradiation through the mask to produce an orientation layer 50 with the desired shape. The resin composition for forming the orientation layer 50 is, for example, a polymerizable acrylic resin.

[0044] An example of the alignment layer 50 will be described. As an example, at least an uneven shape 51 is formed on the alignment surface 50b of the alignment layer 50. Figure 3A shows an example of an alignment layer 50 in which an uneven shape 51 is formed on the alignment surface 50b. By forming an uneven shape 51 on the alignment surface 50b, an alignment restricting force is applied to the alignment layer 50, and the liquid crystal compound of the liquid crystal layer 10 laminated on the alignment layer 50 can be aligned in a predetermined direction. An alignment layer 50 in which an uneven shape 51 is formed on the alignment surface 50b can be formed by the imprint method described above.

[0045] The uneven shape 51 includes recesses 52 and protrusions 53. The depth of the recesses 52 is preferably 2 nm to 200 nm, more preferably 10 nm to 100 nm, and even more preferably 20 nm to 50 nm. By making the depth of the recesses 52 2 nm or more, the liquid crystal compound (liquid crystal molecules) can be more easily oriented. By making the depth of the recesses 52 200 nm or less, the orientation layer 50 can be more easily peeled off from the shaping plate described later, making it easier to form the uneven shape 51 of the orientation layer 50 more stably.

[0046] <Imprint Method> Next, a method for producing the orientation layer 50 by imprinting will be described. The uneven shape 51 of the orientation layer 50 can be formed, for example, by shaping a resin-containing layer using a plate having a shape complementary to the surface shape of the orientation layer 50. More specifically, the orientation layer 50 can be formed, for example, by the following steps 1 and 2.

[0047] Step 1: A step of applying a coating liquid for forming an orientation layer containing resin onto a substrate layer 40 to form a layer containing resin. Step 2: A step of forming a resin-containing layer using a plate having a shape complementary to the surface shape of the orientation layer 50.

[0048] When producing the orientation layer 50 by the imprint method, first, in step 1, an orientation layer forming coating solution containing resin is applied to the substrate layer 40 to form a resin-containing layer. If the orientation layer forming coating solution contains a solvent, it is preferable to dry the solvent in step 1.

[0049] When a curable resin is used as the resin, it is preferable to use a coating solution containing a curable resin composition as the coating solution for forming the orientation layer in step 1. That is, when a curable resin is used as the resin, it is preferable that the curable resin in the coating solution for forming the orientation layer in step 1 is in an uncured state.

[0050] When using a coating solution for forming an orientation layer in step 1 that contains an ionizing radiation-curable resin composition, it is preferable to cure the ionizing radiation-curable resin composition contained in the formed layer by irradiating it with ionizing radiation at the same time as the forming in step 2.

[0051] If another layer, such as a primer layer, is provided between the base layer 40 and the orientation layer 50, it is preferable that a step of forming the other layer on the base layer 40 is performed before step 1.

[0052] Next, in step 2, a layer containing resin is formed using a plate having a shape complementary to the surface shape of the orientation layer 50. The plate used in step 2 can be manufactured by general-purpose means such as laser lithography, electron beam lithography, or FIB (Focused Ion Beam). It is also preferable to manufacture many plates by duplicating the plate manufactured by the aforementioned means, and arrange the many duplicated plates to create a multi-plate. The plate can be duplicated by general-purpose means such as electroforming.

[0053] When the orientation layer 50 is manufactured by the imprint method, the thickness of the orientation layer 50 may be approximately 0.5 μm to 20 μm, or approximately 1 μm to 10 μm. In step 1, where the coating liquid for forming the orientation layer is applied, there is a possibility that foreign matter may be mixed into the coating liquid. Even if foreign matter is mixed into the coating liquid for forming the orientation layer, the orientation layer 50 can be incorporated into the orientation layer 50 because its thickness is 0.5 μm or more. In other words, the foreign matter is less likely to be exposed from the surface of the orientation layer 50. Therefore, the yield is less likely to decrease. A thickness of 0.5 μm or more for the orientation layer 50 makes it easy to create recesses 52 with a depth of 200 nm or less. Furthermore, a thickness of 20 μm or less for the orientation layer 50 makes it less likely that insufficient curing will occur in the curable resin when irradiated with ultraviolet light. Therefore, ease of release of the orientation layer 50 from the mold can be ensured.

[0054] <Photo-Orientation Method> Next, a method for fabricating the orientation layer 50 using the photo-alignment method will be described. Methods for fabricating the orientation layer 50 using the photo-alignment method include a method using two-beam interference and a method of irradiating linearly polarized light using a light-shielding mask.

[0055] In the method using two-beam interference, first, a solution of a birefringence-inducing polymer material dissolved in a solvent is applied to a substrate layer 40. Next, the liquid is dried to create a coated film. Then, an orientation-regulating force is applied to the coated film by two-beam interference using a polarized light beam with good coherence, such as laser light.

[0056] Two methods can be described for forming a liquid crystal layer 10 with different slow axis directions in a first region 21 and a second region 22 using a light-shielding mask. In the first method, a light-shielding mask having a desired periodic pitch is used at least twice to irradiate at least two regions with linearly polarized light having different polarization characteristics and intensities. In the second method, linearly polarized light is first irradiated using a light-shielding mask having a desired periodic pitch. Next, by irradiating with linearly polarized light without using a light-shielding mask, regions with different irradiation energy amounts at a desired periodic pitch are formed. This imparts a periodic structure with molecular orientation directions differing by 90°. Comparing the first and second methods, the second method has the advantage of simplifying the apparatus.

[0057] When the orientation layer 50 is fabricated by a photo-orientation method, the photo-orientation material used to fabricate the orientation layer 50 contains a component having a photoreactive functional group. Thus, the orientation layer 50 fabricated by the photo-orientation method contains a component having a photoreactive functional group. Examples of photoreactive functional groups include those that undergo photodimerization or photoisomerization. An example of a functional group that undergoes photodimerization is a cinnamoyl group. Examples of photo-orientation materials used in the orientation layer 50 according to this embodiment include those described in Japanese Patent Publication Nos. 2006-285197, 2007-76839, 2007-138138, 2007-94071, 2007-121721, 2007-140465, and 2007-156439. , having azo compounds described in Japanese Patent Publication No. 2007-133184, Japanese Patent Publication No. 2009-109831, Japanese Patent No. 3883848 and Japanese Patent No. 4151746, aromatic ester compounds described in Japanese Patent Publication No. 2002-229039, and photo-orienting units described in Japanese Patent Publication No. 2002-265541 and Japanese Patent Publication No. 2002-317013 Examples include maleimide and / or alkenyl-substituted nadiimide compounds, photocrosslinkable silane derivatives described in Japanese Patent No. 4205195 and Japanese Patent No. 4205198, photocrosslinkable polyimides, photocrosslinkable polyamides and photocrosslinkable polyesters described in Japanese Patent Publication No. 2003-520878, Japanese Patent Publication No. 2004-529220 and Japanese Patent No. 4162850, and photodimerizable compounds described in Japanese Patent Publication No. 9-118717, Japanese Patent Publication No. 10-506420, Japanese Patent Publication No. 2003-505561, International Publication No. 2010 / 150748, Japanese Patent Publication No. 2013-177561 and Japanese Patent Publication No. 2014-12823, particularly cinnamate compounds, chalcone compounds and coumarin compounds. Among these, photocrosslinkable polyimides, photocrosslinkable polyamides, photocrosslinkable polyesters, cinnamate compounds, and chalcone compounds are preferred.

[0058] Next, we will describe an exposure apparatus 70 for applying an orientation-regulating force to the orientation layer 50 using a photo-alignment method.

[0059] As shown in Figure 3B, the exposure apparatus 70 comprises a light source 71, a polarizing beam splitter 72, mirrors 73A and 73B, and λ / 4 plates 74A and 74B. The light source 71 includes a laser irradiation unit 75 and a λ / 2 plate (not shown). The light source 71 is configured to emit linearly polarized light P0 by changing the polarization direction of the laser light M emitted from the laser irradiation unit 75.

[0060] The polarizing beam splitter 72 plays the role of separating the laser light M emitted from the light source 71 into two beams, MA and MB.

[0061] Mirrors 73A and 73B are positioned on the optical paths of the two separated rays MA and MB, respectively.

[0062] The λ / 4 plates 74A and 74B have optical axes parallel to each other. The λ / 4 plate 74A converts linearly polarized light P0 (ray MA) to right-circularly polarized light P R Converting to this, the λ / 4 plate 74B converts linearly polarized P0 (light ray MB) to left circularly polarized P L It serves the purpose of converting to [a certain format].

[0063] In such an exposure apparatus 70, the orientation layer 50a, before the orientation pattern is formed, is placed in an exposure section (not shown). Two light rays MA and MB are made to interfere with each other by crossing them on the orientation layer 50a. Due to this interference, the polarization state of the interference light changes periodically in an interference fringe pattern. Next, the orientation layer 50a is exposed by irradiating it with the interference light. As a result, an orientation pattern in which the orientation state changes periodically is obtained in the orientation layer 50. In the exposure apparatus 70, the period of the orientation pattern can be adjusted by changing the intersection angle α of the two light rays MA and MB.

[0064] When the alignment layer 50 is fabricated by photoalignment, the thickness of the alignment layer 50 may be between 1 nm and 1000 nm, or between 60 nm and 300 nm. A thickness of 1 nm or more allows for the incorporation of foreign matter into the alignment layer 50, thus reducing the yield. Furthermore, a thickness of 1000 nm or less reduces the likelihood of the alignment layer 50's sensitivity deteriorating due to polarized exposure. Therefore, the liquid crystal alignment control force is less likely to decrease.

[0065] The orientation layer 50 may be manufactured using a roll-to-roll method. By manufacturing the orientation layer 50 using a roll-to-roll method, the orientation layer 50 can be mass-produced in a short amount of time. The orientation layer 50 may also be manufactured from a single-sheet material. When manufacturing the orientation layer 50 from a sheet, it can be manufactured from a metal plate or a resin plate using the imprint method, or by using a light-shielding mask if using the photo-alignment method.

[0066] The substrate layer 40 and alignment layer 50 may be removed from the optical film 1 at least after the formation of the liquid crystal layer 10. This makes it possible to obtain an optical film 1 that does not have the substrate layer 40 and alignment layer 50.

[0067] <Liquid crystal layer> The liquid crystal layer 10 may include a liquid crystal cured product, i.e., a cured product of a liquid crystal composition. The liquid crystal composition includes a liquid crystal compound. The liquid crystal layer 10 can be produced by forming a coating film by applying a coating solution for liquid crystal layers containing the liquid crystal composition, and then curing the liquid crystal composition. The liquid crystal layer 10 is arranged to span multiple pattern regions 20 of the optical film 1. In particular, the liquid crystal layer 10 is arranged to span a first region 21 and a second region 22 of the optical film 1. In particular, the liquid crystal layer 10 is arranged to span a gap region 23 between the first region 21 and the second region 22 of the optical film 1. In this embodiment, the liquid crystal layer 10 is arranged over the entire area occupied by the optical film 1 when observed from the thickness direction dn.

[0068] As described above, the angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is between 80° and 100°. In the first region 21, the direction of the slow axis of the liquid crystal layer 10 is at an angle of 45° with respect to the first direction d1. On the other hand, in the second region 22, the direction of the slow axis of the liquid crystal layer 10 is at an angle of -45° with respect to the first direction d1. Therefore, the orientation direction of the liquid crystal compound differs between the portion of the liquid crystal layer 10 located in the first region 21 and the portion located in the second region 22. Nevertheless, the portion of the liquid crystal layer 10 located in the first region 21 and the portion located in the second region 22 can be manufactured using the same amount of liquid crystal coating solution to achieve the same thickness. In other words, it is not necessary to apply the liquid crystal coating solution to the first region 21 and the second region 22 under different conditions. In particular, the entire liquid crystal layer 10 can be fabricated using the same liquid crystal coating solution in an amount that results in the same thickness.

[0069] The coating solution for the liquid crystal layer may contain a liquid crystal composition containing liquid crystal compounds, as well as a photopolymerization initiator, a surfactant, a solvent, and other additives. The orientation of the liquid crystal compounds within the coating film may be adjusted to horizontal orientation, vertical orientation, tilted orientation, twisted orientation, hybrid orientation, etc. By controlling the orientation of the liquid crystal compounds within the coating film, the optical properties of each region within the liquid crystal layer 10 can be controlled.

[0070] Examples of liquid crystal compounds for the liquid crystal layer 10 include rod-shaped liquid crystal compounds such as nematic liquid crystal compounds and smectic liquid crystal compounds, and discotic liquid crystal compounds. The liquid crystal compound for the liquid crystal layer 10 may be a rod-shaped liquid crystal compound or a discotic liquid crystal compound. Examples of rod-shaped liquid crystal compounds include nematic liquid crystal compounds and smectic liquid crystal compounds.

[0071] The liquid crystal composition may be a liquid crystal composition that undergoes a polymerization reaction, i.e., a polymerizable liquid crystal composition. The liquid crystal composition may contain a polymerizable liquid crystal compound. The liquid crystal layer 10 may contain a polymerizable liquid crystal compound. The liquid crystal layer 10 may be a cured product of a composition containing a polymerizable liquid crystal compound.

[0072] Polymerizable liquid crystal compounds are liquid crystal compounds that have polymerizable groups. Examples of polymerizable liquid crystal compounds include monofunctional liquid crystal compounds with one polymerizable group and polyfunctional liquid crystal compounds with two or more polymerizable groups. Polymerizable liquid crystal compounds may also be polyfunctional liquid crystal compounds with two to three polymerizable groups, or polyfunctional liquid crystal compounds with two polymerizable groups. The polymerizable groups polymerize upon irradiation with active energy rays such as ultraviolet light. Examples of polymerizable groups include vinyl groups, metachloroyl groups, ethylenically unsaturated double bonds such as acryloyl groups, etc.

[0073] In the liquid crystal layer 10, the liquid crystal compound may be fixed in one of the following orientation states: horizontal orientation, vertical orientation, tilt orientation, twist orientation, or hybrid orientation. For example, the long axis of the rod-shaped liquid crystal compound may be substantially parallel to the surface of the liquid crystal layer 10. Substantially parallel means that the angle between the surface of the liquid crystal layer 10 and the director of the rod-shaped liquid crystal compound is 0° or more and 20° or less. This angle may also be 0° or more and 10° or less, or 0° or more and 5° or less.

[0074] The disc surface of the discotic liquid crystal compound may be substantially orthogonal to the surface of the liquid crystal layer 10. "Substantially orthogonal" means that the average angle between the surface of the liquid crystal layer 10 and the disc surface of the discotic liquid crystal compound is 70° or more and 90° or less. This angle may also be 80° or more and 90° or less, or 85° or more and 90° or less.

[0075] Examples of rod-shaped liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyanosubstituted phenylpyrimidines, alkoxysubstituted phenylpyrimidines, phenyldioxanes, trans, or alkenylcyclohexylbenzonitriles. The rod-shaped liquid crystal compounds may be these low-molecular-weight liquid crystal compounds or these high-molecular-weight liquid crystal compounds. The rod-shaped liquid crystal compounds may contain polymerizable groups. The number of polymerizable groups in one molecule of the rod-shaped liquid crystal compound may be 2 or 3, or 2.

[0076] Discotic liquid crystal compounds are described in various publications (C. Destrade et al., Mol.Crysr.Liq.Cryst., vol.71, page 111 (1981); The Chemical Society of Japan, ed., Quarterly Review of Chemistry, No.22, Chemistry of Liquid Crystals, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew.Chem.Soc.Chem.Comm., page 1794 (1985); J. Zhang et al., J.Am.Chem.Soc., vol.116, page 2655 (1994)). The polymerization of discotic liquid crystal compounds is described in Japanese Patent Publication No. Hei 8-27284.

[0077] The discotic liquid crystal compound may contain polymerizable groups. For example, polymerizable groups may be bonded as substituents to the disc-shaped core of the discotic liquid crystal compound.

[0078] The discotic liquid crystal compound may contain a linking group between the disc-shaped core and the polymerizable group. The inclusion of the linking group allows for stable maintenance of the orientation of the liquid crystal compound during the polymerization reaction. The discotic liquid crystal compound having a polymerizable group may also be a compound represented by the following formula. D(-LP)n In the formula, D is a disc-shaped core, L is a divalent linking group, P is a polymerizable group, and n is an integer between 1 and 12. Specific examples of the disc-shaped core (D), divalent linking group (L), and polymerizable group (P) in the formula are (D1) to (D15), (L1) to (L25), and (P1) to (P18), respectively, as described in Japanese Patent Application Publication No. 2001-4837, and the contents described in the said publication can be used. The phase transition temperature of the discotic liquid crystal compound may be 30°C to 300°C, or 30°C to 170°C.

[0079] The liquid crystal layer 10 may exhibit positive dispersibility, negative dispersibility, or flat dispersibility. Negative dispersibility is a characteristic in which the phase difference imparted to transmitted light increases as the wavelength of the transmitted light becomes longer. Particularly in the optical film 1 intended to act on visible light, when the liquid crystal layer 10 exhibits negative dispersibility, the relationship between the in-plane phase difference (Re(451.6)) with respect to light having a wavelength of 450 nm and the in-plane phase difference (Re(550)) with respect to light having a wavelength of 550 nm is Re(451.6) < Re(550). Particularly in the optical film 1 intended to act on visible light, when the liquid crystal layer 10 exhibits positive dispersibility, the relationship between Re(451.6) and Re(550) is Re(451.6) > Re(550). Particularly in the optical film 1 intended to act on visible light, when the liquid crystal layer 10 exhibits flat dispersibility, the relationship between Re(451.6) and Re(550) is Re(451.6) = Re(550).

[0080] Examples of liquid crystalline compounds exhibiting negative dispersibility include compounds described in each of the published gazettes such as JP-T-2010-537954, JP-T-2010-537955, JP-T-2010-522892, JP-T-2010-522893, JP-T-2013-509458, and each of the patent gazettes such as Patent No. 5892158, Patent No. 5979136, Patent No. 5994,777, Patent No. 6015,655, etc.

[0081] The liquid crystal layer 10 may contain a single type of liquid crystal compound. The liquid crystal layer 10 may contain two or more types of liquid crystal compounds. The liquid crystal compound contained alone in the liquid crystal layer 10 may be a polymerizable liquid crystal compound. At least one of the two or more types of liquid crystal compounds contained in the liquid crystal layer 10 may be a polymerizable liquid crystal compound. All of the two or more types of liquid crystal compounds contained in the liquid crystal layer 10 may be polymerizable liquid crystal compounds. The content of the polymerizable liquid crystal compound may be 60% by mass or more and 99.9% by mass or less, or 65% by mass or more and 98% by mass or less with respect to the total solids of the coating liquid for the liquid crystal layer.

[0082] Examples of photopolymerization initiators added to the liquid crystal layer coating solution include acetophenone, benzophenone, α-hydroxyalkylphenone, Michler ketone, benzoin, benzyldimethyl ketal, benzoylbenzoate, α-acyloxime ester, or thioxanthones. The content of the photopolymerization initiator may be 0.01% to 20% by mass or 0.5% to 5% by mass, relative to the total solid matter in the liquid crystal layer coating solution.

[0083] Examples of surfactants added to the coating solution for the liquid crystal layer include fluorine-based surfactants having polymerizable groups and silicone-based surfactants having polymerizable groups. The coating solution for the liquid crystal layer may contain both fluorine-based and silicone-based surfactants. The surfactant content may be 0.01% by mass or more and 2.0% by mass or 0.1% by mass or more and 1.0% by mass or less, based on the total solid matter in the coating solution for the liquid crystal layer.

[0084] Examples of solvents added to the coating solution for the liquid crystal layer include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), or amides (dimethylformamide, dimethylacetamide, etc.), and mixtures of two or more selected from these. The solvent content may be 50% to 90% by mass or 70% to 80% by mass in the coating solution for the liquid crystal layer.

[0085] The liquid crystal layer 10 can be obtained by curing a coating film of a liquid crystal composition formed on the alignment layer 50. The coating film of the liquid crystal composition is obtained by applying a coating liquid for the liquid crystal layer onto the alignment layer 50 and drying the coating liquid for the liquid crystal layer on the alignment layer 50. The drying conditions can be set according to the composition of the coating liquid for the liquid crystal layer. The drying temperature may be 40°C to 150°C. From the viewpoint of preventing deformation of the substrate layer 40, the drying temperature may be 40°C to 100°C. From the viewpoint of preventing deformation of the substrate layer 40, the drying time may be 30 seconds to 250 seconds, or 50 seconds to 200 seconds. Ultraviolet light may be used when polymerizing the polymerizable liquid crystal compound. The irradiation energy of the ultraviolet light can be set according to the thickness of the liquid crystal layer 10, etc. The irradiation energy of the ultraviolet light is 50 mJ / cm². 2 More than 1000mJ / cm 2 The following is also acceptable: 150 mJ / cm² 2 More than 900mJ / cm 2 The following is also acceptable.

[0086] In this embodiment, the liquid crystal layer 10 functions as a phase difference layer. The portions of the liquid crystal layer 10 located in the first region 21 and the second region 22 impart a phase difference to the incident light. In particular, in an optical film 1 intended to act on visible light, the liquid crystal layer 10 may be a layer that imparts a phase difference of, for example, 1 / 4 wavelength to light with a wavelength of 552.1 nm in the portions located in the first region 21 and the second region 22. The liquid crystal layer 10 may also function as a 1 / 4 wavelength layer that imparts a phase difference to the incident light corresponding to 1 / 4 of the wavelength of the incident light in the portions located in the first region 21 and the second region 22. The in-plane phase difference of the liquid crystal layer 10, which functions as a phase difference layer, may be adjusted according to the application of the optical film 1.

[0087] For an optical film 1 intended to act on visible light, the in-plane phase difference of the liquid crystal layer 10 may be adjusted for light with a wavelength of 552.1 nm. If the liquid crystal layer 10 is a quarter-wavelength layer, the in-plane phase difference of the liquid crystal layer 10 for light with a wavelength of 552.1 nm is, for example, greater than 120 nm and less than 160 nm.

[0088] A method for measuring the in-plane phase difference of a phase difference layer, including the liquid crystal layer 10, will be described. In this disclosure, the in-plane phase difference (Re) of the phase difference layer can be calculated from Nx, Ny, and the thickness d (nm) of the phase difference layer using the following formula. In-plane phase difference (Re)=(Nx-Ny)×d

[0089] In this disclosure, the in-plane phase difference (Re) of the phase difference layer is a value measured using a phase difference measuring device (KOBRA-WR, manufactured by Oji Instruments Co., Ltd.). In this disclosure, the refractive indices Nx and Ny are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.) with a sodium lamp (λ=552.1 nm) as the light source. When measuring wavelength dependence, it can be measured using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter. In addition, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC.) and catalogs of various optical films can be used. Examples of average refractive index values ​​for major optical films are given below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59), and polyester (1.64).

[0090] In this disclosure, the refractive index in the direction in which the in-plane slow axis of the phase difference layer extends is Nx, the refractive index in the direction perpendicular to the direction in which the in-plane slow axis of the phase difference layer extends and the thickness direction of the phase difference layer is Ny, and the refractive index in the thickness direction of the phase difference layer is Nz. The in-plane slow axis is the axis that points in the direction of the axis with the highest refractive index along the in-plane of the phase difference layer.

[0091] The thickness of the liquid crystal layer 10 can be set considering the phase difference imparted to the transmitted light and the birefringence of the fabricated liquid crystal layer 10. The thickness of the liquid crystal layer 10 may be between 0.10 μm and 10 μm.

[0092] <Pattern area> As described above, the optical film 1 includes a plurality of pattern regions 20 aligned in a first direction d1. The plurality of pattern regions 20 include a plurality of first regions 21 and a plurality of second regions 22. As shown in Figure 2, the angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is between 80° and 100°. In the first region 21, the direction of the slow axis of the liquid crystal layer 10 is at an angle of 45° with respect to the first direction d1. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 is at an angle of -45° with respect to the first direction d1.

[0093] In this embodiment, the shape of each of the multiple pattern regions 20, when observed from the thickness direction dn of the optical film 1, is rectangular. Each of the multiple pattern regions 20 has a short side extending in the first direction d1 and a long side extending in the thickness direction dn and the vertical direction dv perpendicular to the first direction d1. In this embodiment, the width of the pattern region 20 in the first direction d1 is smaller than the width of the pattern region 20 in the vertical direction dv. The shape of the first region 21 and the shape of the second region 22 are identical when observed from the thickness direction dn of the optical film 1.

[0094] The width of each of the multiple first regions 21 and the multiple second regions 22 in the first direction d1 is between 45 μm and 240 μm. That is, the width of all of the multiple first regions 21 is between 45 μm and 240 μm. Furthermore, the width of all of the multiple second regions 22 is between 45 μm and 240 μm.

[0095] In the first region 21 of the optical film 1, the alignment layer 50 has an orientation restricting force that aligns the liquid crystal compound in the portion of the liquid crystal layer 10 located in the first region 21 in a predetermined direction. Furthermore, in the second region 22 of the optical film 1, the alignment layer 50 has an orientation restricting force that aligns the liquid crystal compound in the portion of the liquid crystal layer 10 located in the second region 22 in a predetermined direction. As a result, the liquid crystal compound of the liquid crystal layer 10 can be oriented such that the angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is between 80° and 100°. In particular, the liquid crystal compound of the liquid crystal layer 10 can be oriented such that in the first region 21, the direction of the slow axis of the liquid crystal layer 10 forms an angle of 45° with respect to the first direction d1, and in the second region 22, the direction of the slow axis of the liquid crystal layer 10 forms an angle of -45° with respect to the first direction d1.

[0096] In the example shown in Figure 2, each of the multiple pattern regions 20 extends from one end to the other of the optical film 1 in the vertical direction dv.

[0097] As described above, each of the multiple pattern regions 20 further includes a gap region 23 provided between each of the multiple first regions 21 and the multiple second regions 22. The width of the gap region 23 in the first direction d1 is, for example, 140 nm to 4000 nm.

[0098] <Method for manufacturing optical films> The method for manufacturing the optical film 1 of this embodiment will now be described. The method for manufacturing the optical film 1 of this embodiment includes the step of laminating a liquid crystal layer 10 onto an alignment layer 50.

[0099] In the manufacturing method of the optical film 1, first, a base layer 40 is prepared. Subsequently, an orientation layer 50 is formed on the base layer 40 by the means described above, namely the imprint method, rubbing method, or photo-alignment method.

[0100] Next, a method for laminating the liquid crystal layer 10 onto the alignment layer 50 will be described. First, a polymerizable liquid crystal composition is applied onto the alignment layer 50. Subsequently, the applied polymerizable liquid crystal composition is heated to its phase transition temperature to orient the liquid crystal compounds contained in the polymerizable liquid crystal composition. After that, light is irradiated onto the polymerizable liquid crystal composition coating in which the liquid crystal compounds have been oriented. This allows the liquid crystal layer 10 to be formed.

[0101] The method for forming a coating film of a polymerizable liquid crystal composition in the step of aligning the liquid crystal compound when forming the liquid crystal layer 10, and the method for heating the coated polymerizable liquid crystal composition to the phase transition temperature, can be any conventionally known method and are not particularly limited.

[0102] In the step of irradiating the coating film with light when forming the liquid crystal layer 10, a polymerization reaction is caused by irradiating the coating film of the polymerizable liquid crystal composition in which the liquid crystal compounds are oriented with light, thereby polymerizing the polymerizable groups of the polymerizable liquid crystal compounds contained in the liquid crystal layer 10. Conventional known methods can be used as the light irradiation method in the step of irradiating the coating film with light.

[0103] By the above manufacturing method, an optical film 1 can be produced in which a base layer 40, an alignment layer 50, and a liquid crystal layer 10 are laminated in that order, as shown in Figure 1B. Furthermore, by peeling the base layer 40 of the optical film 1 shown in Figure 1B from the parts of the optical film 1 other than the base layer 40, the optical film 1 shown in Figure 1A can be produced.

[0104] <Retardation plate> This disclosure provides a phase difference plate 60 comprising an optical film 1 and a polarizing plate 61 superimposed on the optical film 1. The phase difference plate 60 may be an elliptic polarizing plate or a circular polarizing plate. In this embodiment, unless otherwise specified, the case in which the phase difference plate 60 is an elliptic polarizing plate or a circular polarizing plate will be described. Figure 4 is a cross-sectional view showing the phase difference plate 60 of this embodiment.

[0105] The phase difference plate 60 shown in Figure 4 comprises a polarizing plate 61 and an optical film 1 laminated on the polarizing plate 61. The optical film 1 provided on the phase difference plate 60 is, for example, the optical film 1 described above in this embodiment. In the phase difference plate 60 shown in Figure 4, the first surface 1a of the optical film 1 faces the surface of the polarizing plate 61. The phase difference plate 60 may optionally include a bonding layer located between the optical film 1 and the polarizing plate 61 (not shown). In the example of the phase difference plate 60 in Figure 4, the polarizing plate 61 is placed on the first surface 1a, which is made up of the liquid crystal layer 10, of the optical film 1 in which the alignment layer 50 and the liquid crystal layer 10 are laminated in that order.

[0106] The polarizing plate 61 is superimposed on the optical film 1 such that the angle the polarizing plate 61 makes with respect to the first direction d1 is 0°±5° or 90°±5°. As a result, the absorption axis of the polarizing plate 61 makes an angle of 45°±5° with respect to the slow axis of the liquid crystal layer 10 in either the first region 21 or the second region 22, and an angle of -45°±5° with respect to the slow axis of the liquid crystal layer 10 in the other region 21 or second region 22.

[0107] In this embodiment, the polarizing plate 61 is a plate-shaped plate that allows only light vibrating in a specific direction to pass through. As the polarizing plate 61, one can be appropriately selected from conventionally known polarizing plates. In this embodiment, the polarizing plate 61 is a linear polarizing plate. As an example, the linear polarizing plate 61 includes a polarizer and a polarizer protective layer provided on at least one side of the polarizer. The polarizer is, for example, a stretched film or stretched layer on which a dye having absorption anisotropy is adsorbed. The polarizer may also be a film coated with and cured with a dye having absorption anisotropy. The dye having absorption anisotropy is, for example, a dichroic dye. Specifically, iodine or a dichroic organic dye can be used as the dichroic dye. As the stretched film on which the dye having absorption anisotropy is adsorbed, for example, a polyvinyl alcohol film, polyvinyl formal film, polyvinyl acetal film, ethylene-vinyl acetate copolymer saponified film, etc., which are dyed with iodine or a dye and then stretched can be used. For details regarding the linear polarizing plate used, see, for example, paragraphs 0025 to 0059 of Japanese Patent Publication No. 2021-51287. The thickness of the polarizing plate is, for example, 2 μm or more and 100 μm or less, preferably 10 μm or more and 60 μm or less.

[0108] In this embodiment, the adhesive or bonding agent for the bonding layer can be appropriately selected from conventionally known ones. Any bonding type can be suitably used as the adhesive or bonding agent for the bonding layer, such as pressure-sensitive adhesives, two-component curing adhesives, UV-curing adhesives, thermosetting adhesives, and heat-melt adhesives. As the adhesive for the bonding layer, a bonding agent composition using a (meth)acrylic resin as the base polymer is preferable from the viewpoint of transparency, weather resistance, heat resistance, etc. The thickness of the bonding layer is determined according to the bonding strength, etc., but may be, for example, 1 μm to 50 μm, preferably 2 μm to 45 μm, more preferably 3 μm to 40 μm, and even more preferably 5 μm to 35 μm.

[0109] The phase difference plate 60 of this embodiment may further include, in addition to the optical film 1, polarizing plate 61, and bonding layer, other layers provided by known optical components such as known circular polarizers and known elliptical polarizers. These other layers are not particularly limited as long as they are layers provided by known optical components. Examples of these other layers include other liquid crystal layers (phase difference layers) different from the liquid crystal layer 10 of this embodiment, as well as anti-reflective layers, diffusion layers, anti-glare layers, anti-static layers, protective films, and the like.

[0110] The phase difference plate 60, which is an elliptic polarizer or a circular polarizer in this embodiment, can be suitably used as an optical element for display devices to reduce the amount of ambient light reflected off the surface of the display device components and emitted to the outside. By using the phase difference plate 60 in an image display device, particularly an organic EL display device (organic electroluminescent display device), the reflection of ambient light off the surface of the image display device components can be reduced. By using the phase difference plate 60 as an optical element for image display devices to reduce the emission of reflected light, the image display device becomes easier to see. A display device incorporating the phase difference plate 60 as an optical element to reduce the emission of reflected light will be described later.

[0111] <Method for manufacturing a phase difference plate> The method for manufacturing the phase difference plate 60 of this embodiment will now be described. The method for manufacturing the phase difference plate 60 comprises the steps of preparing a polarizing plate 61, preparing an optical film 1, and laminating the optical film 1 and the polarizing plate 61.

[0112] As an example of the process for preparing a polarizing plate 61, we will describe the case in which a stretched film on which an absorption-anisotropic dye is adsorbed is used as the polarizer. A stretched film on which an absorption-anisotropic dye is adsorbed can usually be manufactured by a process of uniaxial stretching of a polyvinyl alcohol-based resin film, a process of dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, a process of treating the polyvinyl alcohol-based resin film on which the dichroic dye has been adsorbed with an aqueous boric acid solution, and a process of washing with water after treatment with the aqueous boric acid solution. A polarizing plate 61 can be manufactured by laminating a polarizer protective layer to one or both sides of the obtained polarizer. The polarizing plate 61 can be prepared, for example, by referring to paragraphs 0025 to 0059 of Japanese Patent Application Publication No. 2021-51287.

[0113] The steps for preparing the optical film 1 of this embodiment are not particularly limited, as long as the optical film 1 of this embodiment can be prepared. The steps for preparing the optical film 1 of this embodiment can be carried out by the same method as the method for manufacturing the optical film 1 described above.

[0114] When preparing the optical film 1, if an alignment layer 50 and a liquid crystal layer 10 are formed on the base layer 40, it is preferable to prepare the optical film 1 so that the base layer 40 is peelable from the alignment layer 50 and the liquid crystal layer 10. The means for making the base layer 40 peelable from the alignment layer 50 and the liquid crystal layer 10 are not particularly limited. For example, the base layer 40 can be surface-treated so that it is peelable from the alignment layer 50 and the liquid crystal layer 10. The base layer 40 can be mold-released so that it is peelable from the alignment layer 50 and the liquid crystal layer 10. A mold-release layer can be formed on the surface of the base layer 40 so that it is peelable from the alignment layer 50 and the liquid crystal layer 10.

[0115] The process of laminating the optical film 1 and the polarizing plate 61 can be carried out by bonding the optical film 1 and the polarizing plate 61 with a bonding layer. The bonding layer used to bond the optical film 1 and the polarizing plate 61 can be the same as the bonding layer described above.

[0116] In the process of laminating the optical film 1 and the polarizing plate 61, if the optical film 1 and the polarizing plate 61 are bonded together by a bonding layer, the base layer 40 may be peeled off from the alignment layer 50 and the liquid crystal layer 10 after bonding. In particular, if the base layer 40 is made of a material with a phase difference, such as PET, it is preferable to peel the base layer 40 off from the alignment layer 50 and the liquid crystal layer 10. By peeling off the base layer 40 later, a phase difference plate 60 can be obtained, comprising the polarizing plate 61 and the optical film 1 which has an alignment layer 50 and a liquid crystal layer 10 but no base layer 40. As described above, by preparing the optical film 1 so that the base layer 40 can be peeled off from the alignment layer 50 and the liquid crystal layer 10, the base layer 40 can be peeled off from the alignment layer 50 and the liquid crystal layer 10 after bonding the optical film 1 and the polarizing plate 61. If the substrate layer 40 is made of a material with an extremely small phase difference, such as ZeroTack® or cycloolefin polymer (COP) manufactured by Konica Minolta, Inc., the phase difference plate 60 may be completed while the substrate layer 40 remains in close contact with the alignment layer 50 and the liquid crystal layer 10 without being peeled off. In particular, in an optical film 1 intended to act on visible light, the in-plane phase difference of the substrate layer 40 with an extremely small phase difference for light at 552.1 nm is preferably 20 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less.

[0117] <Image display device, image display panel> This disclosure provides an image display panel 101 equipped with the phase difference plate 60 of this embodiment. Furthermore, this disclosure provides an image display device 100 equipped with the phase difference plate 60 of this embodiment. Figure 5 is a cross-sectional view showing the image display device 100 of this embodiment. As an example, the phase difference plate 60 equipped in the image display device 100 or the image display panel 101 is an elliptic polarizer or a circular polarizer.

[0118] In this embodiment, the image display device 100 comprises an image display panel 101 having a phase difference plate 60 and a display device body 102. The display device body 102 refers to the portion of the image display device 100 that combines the portion that emits light and the portion that is located further from the phase difference plate 60 than the portion that emits light. The image display panel 101 refers to the portion of the image display device 100 that is located on the light-emitting side of the display device body 102. The image display panel 101 comprises a phase difference plate 60 and a panel body 106. The phase difference plate 60 is arranged on the panel body 106. In other words, the panel body 106 is located between the phase difference plate 60 and the display device body 102.

[0119] The image display device 100 may be, for example, a light-emitting display device, a liquid crystal display device, etc., but is not limited to these. The image display device 100 may also be a touch panel equipped with a touch sensor. The image display device 100 may also be a flexible display device.

[0120] In this embodiment, the image display device 100 is preferably a light-emitting display device. By having an image display device that is a light-emitting display device and includes a phase difference plate 60 which is an elliptical polarizer or a circular polarizer, the reflection of ambient light on the surface of the components of the image display device 100 can be reduced. In the example shown in Figure 5, the image display device 100 is an organic EL display device.

[0121] The image display device 100 of this embodiment may be designed to allow the user to rotate the image display device to any angle for observation, or to observe from multiple viewpoints. The image display device 100 may, for example, be able to rotate around an axis perpendicular to the display surface. In other words, the image display device 100 may be designed to allow the azimuth angle ψ of the observation direction, as described later, to change. Examples of image display devices that are designed to be rotated by the user include smartphones and tablet devices. The image display device 100 of this embodiment may not be designed to allow stereoscopic viewing of images. In other words, the image display device 100 may be designed to allow observation of two-dimensional images. Furthermore, the image display device 100 of this embodiment may be designed to allow observation from an observation direction with a large angle with respect to the thickness direction dn (an observation direction with a small elevation angle θ, as described later). As described later, the optical film 1 of this embodiment can minimize the difference in appearance due to differences in the elevation angle θ and azimuth angle ψ of the observation direction. Because of this effect, the image display device 100 equipped with the optical film 1 of this embodiment can be suitably used as an image display device that can be rotated by the user, or as an image display device that can be observed from an observation direction with a large angle with respect to the thickness direction dn.

[0122] The image display device 100 shown in Figure 5 is an organic EL display device and therefore has a plurality of organic EL elements 104 and electrode portions 105 that are electrically connected to each of the plurality of organic EL elements 104. The electrode portion 105 has a light-emitting side portion 105a located on the side of the organic EL element 104 that emits light. Furthermore, the image display device 100 has a first substrate 107 located on the side of the organic EL element 104 that emits light and a second substrate 108 located on the opposite side from the side of the organic EL element 104 that emits light. In this case, the plurality of organic EL elements 104 correspond to the light-emitting portion of the image display device 100. Therefore, the portion consisting of the plurality of organic EL elements 104, the portion of the electrode portion 105 other than the light-emitting side portion 105a, and the second substrate 108 corresponds to the display device body 102. The portion consisting of the light-emitting side portion 105a of the electrode portion 105 and the first substrate 107 corresponds to the panel body 106.

[0123] The panel body 106 is the part that covers the light-emitting side of the display device body 102. Therefore, the panel body 106 can reduce the visibility of the image display device 100 by reflecting ambient light incident on the image display device 100. By providing the image display device 100 or the image display panel 101 with a phase difference plate 60 which is an elliptical polarizer or a circular polarizer, the reflection of ambient light on the surface of the panel body 106 can be reduced.

[0124] In the example shown in Figure 5, the second surface 1b of the optical film 1 provided on the phase difference plate 60 faces the surface of the panel body 106. The image display device 100 shown in Figure 5 further includes a bonding layer 103. The bonding layer 103 bonds the second surface 1b of the optical film 1 provided on the phase difference plate 60 to the surface of the panel body 106. The bonding layer 103 can be the same as the bonding layer described above. In the example shown in Figure 5, the image display device 100 comprises the display device body 102, the panel body 106, the bonding layer 103, the optical film 1, and the polarizing plate 61 in this order.

[0125] In the image display device 100 and image display panel 101 of this embodiment, the distance w1 between the liquid crystal layer 10 of the optical film 1 and the panel body 106 is 1 μm or more and 120 μm or less. In the example shown in Figure 5, the distance w1 corresponds to the sum of the thickness of the portion of the phase difference plate 60 located between the liquid crystal layer 10 and the panel body 106 and the thickness of the bonding layer 103.

[0126] In the example shown in Figure 5, the alignment layer 50 is positioned closer to the display device body 102 than the liquid crystal layer 10. Although not shown, the liquid crystal layer 10 may also be positioned closer to the display device body 102 than the alignment layer 50. By positioning the liquid crystal layer 10 closer to the display device body 102 than the alignment layer 50, the distance w1 between the liquid crystal layer 10 of the optical film 1 and the panel body 106 can be reduced, thereby more effectively reducing the reflection of ambient light on the surface of the panel body 106.

[0127] In the example shown in FIG. 5, the pixel pitch p2 in the image display device 100 does not match the pitch p1 of the pattern region 20 described above. The pixel pitch p2 is, for example, 5 μm or more and 500 μm or less. The pitch p1 of the pattern region 20 is, for example, 3.5 times or more and 350 times or less the pixel pitch p2. In the image display device 100, which is an organic EL display device shown in FIG. 5, the pixel pitch p2 is the array pitch of the organic EL elements 104.

[0128] <Method for manufacturing an image display device, method for manufacturing an image display panel> A method for manufacturing the image display device 100 shown in FIG. 5 and a method for manufacturing the image display panel 101 will be described. The image display device 100 and the image display panel 101 can be manufactured by joining the optical film 1 and the panel body 106 through the bonding layer 103.

[0129] <For VR applications> The optical film 1 of this embodiment can also be incorporated into an image display device for VR applications. An image display device for VR applications is, for example, a VR headset. In an image display device for VR applications, it is expected that the difference in field of view will be large when the user observes the center of the screen and when the user observes the edges of the screen, due to the short distance from the screen of the image display device to the user's eyes. Furthermore, in an image display device for VR applications, it is expected that the user's observation direction will change significantly in a short period of time, for example, by moving their gaze up, down, left, or right in a short period of time. For example, with regard to VR headsets, it is expected that the user will move their gaze from the center of the screen to the edges of the screen in a short period of time. In this case, it is thought that the observation direction will change significantly in a short period of time due to the short distance from the screen of the VR headset to the user's eyes. As will be described later, the optical film 1 of this embodiment can minimize the difference in appearance due to differences in the elevation angle θ and azimuth angle ψ of the observation direction. Because of this effect, the optical film 1 of this embodiment can be suitably incorporated into image display devices for VR applications where there is a large difference in the field of view between observing the center of the screen and observing the edges of the screen, and where the observation direction is expected to change significantly in a short period of time. As an example, an image display device for VR applications is formed by arranging an optical element between a display having a screen for displaying images and a lens facing the user's eyes, for virtually reproducing the light rays of a three-dimensional object using light emitted from the screen of the display. The optical element arranged between the display and the lens may include a quarter-wave plate. The optical film 1 of this embodiment may be used as a quarter-wave plate included in the optical element. In this case, the optical element may include only one optical film 1 of this embodiment, or it may include multiple optical films 1 of this embodiment.

[0130] <Effects and Effects> The effects of the optical film 1 of this embodiment will now be explained. As described above, a phase difference plate 60, which is an elliptical polarizer or a circular polarizer, can be manufactured using the optical film 1. By using the phase difference plate 60 in the image display device 100, the reflection of ambient light on the surfaces of the components of the image display device 100, particularly the surface of the panel body 106, can be reduced.

[0131] To further explain the effects of the optical film 1 of this embodiment, we consider a circular polarizer having a liquid crystal layer and a linear polarizer superimposed on the liquid crystal layer as a comparative example. In the comparative example's circular polarizer, the direction of the phase-lagging axis of the liquid crystal layer is uniform throughout the liquid crystal layer and forms a 45° angle with respect to the absorption axis of the linear polarizer. We will now consider how such a comparative example's circular polarizer appears when used in an image display device.

[0132] Figures 6A and 6B are diagrams illustrating how to represent the direction in which an optical component is observed when describing how optical components such as the circular polarizer of the comparative example described above and the phase difference plate 60 of this embodiment appear. Figures 6A and 6B show how a point P1 located on the surface MTa of the optical component MT is observed from the observation direction d3. Figure 6A shows the optical component MT as observed from a direction parallel to the surface MTa of the optical component MT. Figure 6B shows the optical component MT as observed from a direction perpendicular to the surface MTa of the optical component MT. The angle that the observation direction d3 makes with the surface MTa is called the elevation angle θ. In the observation from a direction perpendicular to the surface MTa of the optical component MT, as shown in Figure 6B, the angle that the observation direction d3 makes with a virtual reference line n2 extending from point P1 and parallel to the surface MTa is called the azimuth angle ψ.

[0133] Let us consider the case where the circular polarizer of the comparative example is used in an image display device, and natural light is irradiated onto the image display device as ambient light. In this case, it is known that a color can be observed on the image display device depending on the observation direction d3. The observed color changes depending on the relationship between the observation direction d3 and the direction of the slow axis of the liquid crystal layer in the circular polarizer and the direction of the absorption axis of the linear polarizer. In particular, even when the display device body of the image display device is not displaying an image and the display device body is black, a color can be observed when the display device body is observed through the circular polarizer. In particular, when the elevation angle θ of the observation direction d3 is sufficiently smaller than 90° (for example, when the elevation angle θ is 60°), depending on the azimuth angle ψ, a strong yellow color may appear, or a strong blue color may appear. Let the azimuth angle ψ of the observation direction d3 in which a strong yellow color appears be azimuth angle ψ1, and the azimuth angle ψ of the observation direction d3 in which a strong blue color appears be azimuth angle ψ2. At this time, the difference between azimuth angle ψ1 and azimuth angle ψ2 is 90°.

[0134] In contrast, the optical film 1 of this embodiment includes a plurality of pattern regions 20, which include a plurality of first regions 21 and a plurality of second regions 22. The angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is 80° or more and 100° or less. The effect of this will be explained. By stacking the polarizing plate 61 on the liquid crystal layer 10 such that the angular difference between the direction of the absorption axis of the polarizing plate 61 and the direction of the slow axis of the liquid crystal layer 10 is close to 45°, a phase difference plate 60 that functions as an elliptical polarizing plate or a circular polarizing plate can be manufactured. By stacking the polarizing plate 61 on the liquid crystal layer 10 such that the angular difference between the direction of the absorption axis of the polarizing plate 61 and the direction of the slow axis of the liquid crystal layer 10 is 45°±5°, in other words, 40° or more and 50° or less, a phase difference plate 60 that functions as an elliptical polarizing plate or a circular polarizing plate can be manufactured. The "angle difference between the direction of the absorption axis of the polarizer 61 and the direction of the slow axis of the liquid crystal layer 10" is a positive value representing the angle between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22. By definition, the "angle difference between the direction of the absorption axis of the polarizer 61 and the direction of the slow axis of the liquid crystal layer 10" cannot be a negative number.

[0135] If the angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is 80° or more and 100° or less, then by adjusting the orientation of the polarizing plate 61 and superimposing the polarizing plate 61 on the liquid crystal layer 10, the angular difference between the direction of the absorption axis of the polarizing plate 61 and the direction of the slow axis of the liquid crystal layer 10 can be brought close to 45° in both the first region 21 and the second region 22. In particular, the angular difference between the direction of the absorption axis of the polarizing plate 61 and the direction of the slow axis of the liquid crystal layer 10 can be set to 45° ± 5° in both the first region 21 and the second region 22. As a result, a phase difference plate 60 that functions as an elliptical polarizing plate or a circular polarizing plate can be manufactured using an optical film 1 equipped with a liquid crystal layer 10. Let's consider the case of observing an image display device 100 using this phase difference plate 60. In this case, at an azimuth angle ψ in which a strong yellow tint is observed in the first region 21 of the optical film 1, a strong blue tint is observed in the second region 22 of the optical film 1. On the other hand, at an azimuth angle ψ in which a strong blue tint is observed in the first region 21 of the optical film 1, a strong yellow tint is observed in the second region 22 of the optical film 1. As a result, the tint in the first region 21 and the tint in the second region 22 are neutralized. Therefore, by using the phase difference plate 60 equipped with the optical film 1 of this embodiment in the image display device 100, the tint is less likely to be observed in the image display device 100, regardless of the azimuth angle ψ of the observation direction d3. In particular, even when the display device body 102 of the image display device 100 is displayed as black and the display device body 102 is observed through the optical film 1, the observer can be made to observe a black color with less color mixing.

[0136] As an example, in the first region 21, the direction of the slow axis of the liquid crystal layer 10 forms an angle of 45° with respect to the first direction d1. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 forms an angle of -45° with respect to the first direction d1. In the first region 21, the direction of the slow axis of the liquid crystal layer 10 may be 45±5° with respect to the first direction d1, in other words, an angle of 40° or more and 50° or less. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 may be -45±5° with respect to the first direction d1, in other words, an angle of -50° or more and -40° or less. By stacking a polarizing plate 61 on the optical film 1 of this embodiment such that the angle of the absorption axis with respect to the first direction d1 is 0°±5° or 90°±5°, a phase difference plate 60 that functions as an elliptical polarizer or a circular polarizer can be manufactured. From a manufacturing standpoint, it is preferable that the direction of the slow axis of the liquid crystal layer 10 in the first region 21 is at an angle of 45±5° with respect to the first direction d1, and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is at an angle of -45±5° with respect to the first direction d1. From a manufacturing standpoint, it is more preferable that the direction of the slow axis of the liquid crystal layer 10 in the first region 21 is at an angle of 45° with respect to the first direction d1, and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is at an angle of -45° with respect to the first direction d1.

[0137] The direction of the slow axis of the liquid crystal layer 10 can be determined by microscopic observation using the following method. A polarizing optical microscope (product name "BX51-P", manufactured by Olympus Corporation) is used to select a clean area of ​​the optical film 1 free of dirt and wrinkles, and the surface is observed by transmission at a magnification of 100x. Specifically, the optical film 1 is rotated with polarizing plates crossed nicols, and the direction of the absorption axis of the polarizer contained in the polarizing optical microscope when the brightness is at its maximum is determined as the direction of the slow axis of the liquid crystal layer 10 in the observed region.

[0138] The direction of the absorption axis of the polarizing plate 61 can be determined as follows. First, a polarization tester (manufactured by Edmund Optics Co., Ltd.) with a predetermined absorption axis direction is placed on top of the polarizing plate 61 whose absorption axis direction is to be measured. Next, with the polarizing tester and the polarizing plate 61 superimposed, the polarizing tester is rotated relative to the polarizing plate 61 until the polarizing tester and the polarizing plate 61 are crossed nicols. The direction perpendicular to the absorption axis direction of the polarizing tester when the polarizing tester and the polarizing plate 61 are crossed nicols is determined as the direction of the absorption axis of the polarizing plate 61.

[0139] Furthermore, the width of each of the multiple first regions 21 and the multiple second regions 22 in the first direction d1 is between 45 μm and 240 μm.

[0140] The effect of making the width of each of the multiple first regions 21 and multiple second regions 22 in the first direction d1 45 μm or more will be explained using Figures 7A and 7B. Figure 7A is a cross-sectional view of an image display device 100 using a phase difference plate 60 equipped with an optical film 1, where the width of the first region 21 and the second region 22 in the first direction d1 is sufficiently wide. Figure 7B is a cross-sectional view of an image display device 100 using a phase difference plate 60 equipped with an optical film 1 in which the width of the first region 21 and the second region 22 in the first direction d1 is narrower than that of the optical film 1 shown in Figure 7A. Figures 7A and 7B are cross-sectional views of the image display device 100 cut in sections parallel to the thickness direction dn and the first direction d1. In Figures 7A, 7B and Figure 7C, which will be described later, only the general shape is shown for the panel body 106 and the display device body 102, and detailed structural illustrations are omitted. The lines labeled L1 in Figures 7A and 7B show an example of the optical path of ambient light that enters the image display device 100 from a direction perpendicular to the vertical direction dv and non-parallel to the thickness direction dn, and is reflected off the surface of the panel body 106.

[0141] When the width of the first region 21 and the second region 22 in the first direction d1 is sufficiently wide, as shown in Figure 7A, ambient light that is incident on the first region 21 of the optical film 1 from a direction perpendicular to the vertical direction dv and reflected off the surface of the panel body 106 can easily pass through the same first region 21 from which it was incident. Ambient light that has passed through the polarizing plate 61, been converted to linear polarization, is incident on the first region 21 of the optical film 1, is reflected off the surface of the panel body 106, and passes through the first region 21 of the optical film 1 again cannot pass through the polarizing plate 61 again. Similarly, ambient light that is incident on the second region 22 of the optical film 1 and reflected off the surface of the panel body 106 can easily pass through the same second region 22 from which it was incident. Ambient light that has passed through the polarizing plate 61, been converted to linear polarization, is incident on the first region 21 of the optical film 1, is reflected off the surface of the panel body 106, and passes through the first region 21 of the optical film 1 again cannot pass through the polarizing plate 61 again. Due to the above effects, when the width of the first region 21 and the second region 22 in the first direction d1 is sufficiently wide, the reflection of ambient light incident on the first region 21 and the reflection of ambient light incident on the second region 22 can be sufficiently reduced.

[0142] In contrast, when the width of the first region 21 and the second region 22 in the first direction d1 is particularly narrow, as shown in Figure 7B, ambient light incident on the first region 21 of the optical film 1 and reflected off the surface of the panel body 106 is likely to pass through the second region 22. Furthermore, ambient light incident on the second region 22 of the optical film 1 and reflected off the surface of the panel body 106 is likely to pass through the first region 21. Reflected light that has passed through such an optical path can pass through the polarizing plate 61 again and be emitted to the outside of the image display device 100. For this reason, when the width of the first region 21 and the second region 22 in the first direction d1 is particularly narrow, it is thought that reflected light will be more easily observed and the observed brightness will be higher depending on the observation direction d3 of the image display device 100. In particular, it is thought that reflected light will be more easily observed and the observed brightness will be higher when observing from an observation direction d3 that is perpendicular to the vertical direction dv and has a relatively small elevation angle θ. Furthermore, if ambient light incident on the first region 21 and reflected passes through the second region 22, and ambient light incident on the second region 22 and reflected passes through the first region 21, the effect of neutralizing the color in the first region 21 and the color in the second region 22 decreases.

[0143] The inventors of this case have diligently researched the width of the first region 21 and the second region 22 in the first direction d1. As a result, it was found that if the width of the first region 21 and the second region 22 in the first direction d1 is 45 μm or more, the reflection of ambient light incident on the first region 21 and the reflection of ambient light incident on the second region 22 can be sufficiently reduced. Furthermore, it was found that if the width of the first region 21 and the second region 22 in the first direction d1 is 45 μm or more, the effect of neutralizing the color of the first region 21 and the color of the second region 22 can be fully exerted. In particular, the inventors of this case have found the condition that the width of the first region 21 and the second region 22 in the first direction d1 is 45 μm or more by testing a phase difference plate 60 having an optical film 1 that has been actually manufactured, taking into account real-world conditions. The width of the first region 21 and the second region 22 in the first direction d1 may be 80 μm or more. If the width of the first region 21 and the second region 22 in the first direction d1 is 80 μm or more, the above-mentioned effects can be exerted more effectively.

[0144] In the optical film 1 of this embodiment, each of the multiple pattern regions 20 extends from one end to the other of the optical film 1 in the vertical direction dv. As a result, each of the multiple first regions 21 extends from one end to the other of the optical film 1 in the vertical direction dv. Furthermore, each of the multiple second regions 22 extends from one end to the other of the optical film 1 in the vertical direction dv. This effect will be explained using Figure 7C. Figure 7C is a cross-sectional view of the image display device 100 cut in a section parallel to the thickness direction dn and the vertical direction dv. In particular, Figure 7C is a cross-sectional view of the image display device 100 cut in a section passing through the first region 21 of the optical film 1. The line denoted by reference numeral L2 in Figure 7C shows an example of the optical path of ambient light incident on the image display device 100 from a direction perpendicular to the first direction d1 and not parallel to the thickness direction dn, and reflected off the surface of the panel body 106.

[0145] Since each of the multiple first regions 21 extends from one end to the other of the optical film 1 in the vertical direction dv, as shown in Figure 7C, ambient light that is incident on the first region 21 of the optical film 1 from a direction perpendicular to the first direction d1 and reflected off the surface of the panel body 106 passes through the same first region 21 from which it was incident. Similarly, although not shown in the figure, ambient light that is incident on the second region 22 of the optical film 1 from a direction perpendicular to the first direction d1 and reflected off the surface of the panel body 106 passes through the same second region 22 from which it was incident. Therefore, even when ambient light is incident on the optical film 1 from a direction perpendicular to the first direction d1, the reflection of ambient light incident on the first region 21 and the reflection of ambient light incident on the second region 22 can be sufficiently reduced. Furthermore, even when ambient light is incident on the optical film 1 from a direction perpendicular to the first direction d1, the effect of neutralizing the color in the first region 21 and the color in the second region 22 can be fully realized.

[0146] As described above, with the optical film 1 of this embodiment, it becomes less likely that an observation direction d3 in which particularly high brightness is observed will occur. This makes it possible to keep the difference in brightness observed depending on the observation direction d3 small. In particular, it is possible to keep the difference in brightness observed due to the difference in elevation angle θ and azimuth angle ψ of the observation direction d3 small. Furthermore, it becomes less likely that an observation direction d3 in which particularly strong color is observed will occur. This makes it possible to keep the difference in color observed depending on the observation direction d3 small. In particular, it is possible to keep the difference in color observed due to the difference in elevation angle θ and azimuth angle ψ of the observation direction d3 small. As described above, it is possible to keep the difference in appearance depending on the direction in which the optical film 1 is viewed small.

[0147] Thus, an optical film 1 in which the difference in appearance depending on the viewing direction is kept to a minimum is considered to have little difference in appearance even when viewed by a user rotating the optical film 1 around an axis perpendicular to its surface. Such an optical film 1 is particularly suitable for use in the display devices described above, which are expected to be rotated by the user.

[0148] By setting the width of each of the multiple first regions 21 and multiple second regions 22 in the first direction d1 to 240 μm or less, the pattern of the multiple first regions 21 and multiple second regions 22 arranged together becomes sufficiently difficult for an observer to distinguish. The width of the first region 21 and the second region 22 in the first direction d1 may also be 120 μm or less. If the width of the first region 21 and the second region 22 in the first direction d1 is 120 μm or less, the above effect can be exerted more effectively.

[0149] Furthermore, in the optical film 1 of this embodiment, the plurality of pattern regions 20 further include gap regions 23 provided between each of the plurality of first regions 21 and the plurality of second regions 22. To explain the effect of the gap regions 23, as a comparative example, consider an optical film 1 in which the plurality of pattern regions 20 do not include gap regions 23, and the first region 21 and the second region 22 are in contact with each other.

[0150] The inventors of this case have found, through their research, that in the optical film 1 in which the first region 21 and the second region 22 are in contact with each other, as in the comparative example above, the orientation of the liquid crystal compounds in the liquid crystal layer 10 is easily disrupted near the boundary between the first region 21 and the second region 22. The reason for this is thought to be as follows: In the optical film 1 of the comparative example above, in which the first region 21 and the second region 22 are in contact with each other and whose slow phase axes are orthogonal to each other, it is required to abruptly change the orientation direction of the liquid crystal compounds in the liquid crystal layer 10 at the boundary between the first region 21 and the second region 22. However, since it is practically difficult to abruptly change the orientation direction of the liquid crystal compounds in the liquid crystal layer 10 at this boundary, it is thought that the orientation of the liquid crystal compounds in the liquid crystal layer 10 is easily disrupted near this boundary. If the orientation of the liquid crystal compound in the liquid crystal layer 10 is disrupted near the boundary, it is thought that the effect of reducing the emission of reflected light and the effect of neutralizing the color in the first region 21 and the color in the second region 22 may be reduced near the boundary.

[0151] Furthermore, the inventors of this invention have found through their research that by providing gap regions 23 between each of the multiple first regions 21 and multiple second regions 22, the orientation of the liquid crystal compounds in the liquid crystal layer 10 in the first region 21 and the second region 22 becomes less likely to be disturbed. This is because, in the optical film 1 in which gap regions 23 are provided between the first region 21 and the second region 22, it is not necessary to abruptly change the orientation direction of the liquid crystal compounds in the liquid crystal layer 10. Therefore, the optical film 1 with gap regions 23 can fully exhibit the effects of making it less likely for reflected light to be emitted by making it less likely for the orientation of the liquid crystal compounds in the liquid crystal layer 10 to be disturbed, and the effect of neutralizing the color in the first region 21 and the color in the second region 22.

[0152] In particular, the inventors of this invention, by testing the optical film 1 that was actually manufactured, discovered that in the optical film 1 where the first region 21 and the second region 22 are in contact with each other, the orientation of the liquid crystal compound in the liquid crystal layer 10 is easily disrupted, as described above. Considering this problem, they conceived of providing a gap region 23 between the first region 21 and the second region 22, and completed the optical film 1 of this embodiment. The above problem can only be discovered by testing the optical film 1 that was actually manufactured, and is considered to be a problem that would be difficult to discover by, for example, simulation testing.

[0153] In this embodiment, the width of the gap region 23 in the first direction d1 can be 140 nm or more and 4000 nm or less. By setting the width of the gap region 23 in the first direction d1 to 140 nm or more, the effect of the gap region 23 in making the orientation of the liquid crystal compound of the liquid crystal layer 10 less disordered can be exhibited more stably. By setting the width of the gap region 23 in the first direction d1 to 4000 nm or less, the ratio of the area of ​​the gap region 23 to the area of ​​the first region 21 and the second region 22 can be made sufficiently large. This allows the optical film 1 to fully exhibit the effect of making it difficult for reflected light to be emitted and the effect of neutralizing the color of the first region 21 and the color of the second region 22.

[0154] The optical film 1 of this embodiment further comprises an alignment layer 50. The liquid crystal layer 10 is laminated on the alignment layer 50. As a result, the liquid crystal compound of the liquid crystal layer 10 can be aligned in a desired orientation direction by the action of the alignment layer 50.

[0155] In the optical film 1 of this embodiment, at least an uneven shape 51 may be formed on the surface of the alignment layer 50 on which the liquid crystal layer 10 is laminated. By using such an alignment layer 50, a liquid crystal layer 10 can be formed in which the direction of the slow axis in the first region 21 and the second region 22 is adjusted as described above.

[0156] In the optical film 1 of this embodiment, the alignment layer 50 may contain a component having a functional group that produces photoreactivity. By using such an alignment layer 50, a liquid crystal layer 10 can be formed in which the direction of the slow axis in the first region 21 and the second region 22 is adjusted as described above.

[0157] The phase difference plate 60 of this embodiment comprises the optical film 1 of this embodiment and a polarizing plate 61 superimposed on the optical film 1 such that the angle it makes with respect to the first direction d1 of the absorption axis is 0°±5° or 90°±5°. The phase difference plate 60 of this embodiment can function as an elliptical polarizing plate or a circular polarizing plate. By using such a phase difference plate 60 in the image display device 100, the reflection of ambient light on the surfaces of the components of the image display device 100, particularly the surface of the panel body 106, can be reduced. Furthermore, the difference in appearance depending on the viewing direction of the image display device 100 can be kept to a minimum.

[0158] The image display panel 101 of this embodiment includes a phase difference plate 60 of this embodiment. In the image display panel 101 of this embodiment, the reflection of ambient light on the surface of the members of the image display panel 101 can be reduced by the phase difference plate 60. Furthermore, the difference in appearance depending on the viewing direction of the image display panel 101 can be kept to a minimum.

[0159] The image display device 100 of this embodiment includes the phase difference plate 60 of this embodiment. In the image display device 100 of this embodiment, the reflection of ambient light on the surface of the components of the image display device 100 can be reduced by the phase difference plate 60. Furthermore, the difference in appearance depending on the viewing direction of the image display device 100 can be kept to a minimum.

[0160] The image display panel 101 of this embodiment further comprises a panel body 106. Furthermore, the image display device 100 of this embodiment further comprises a panel body 106. The phase difference plate 60 is arranged on the panel body 106. The distance w1 between the liquid crystal layer 10 and the panel body 106 is 1 μm or more and 120 μm or less.

[0161] The following effects are obtained when the distance w1 is 120 μm or less. The larger the distance w1, the more likely it is that ambient light incident on the first region 21 of the optical film 1 and reflected off the surface of the panel body 106 will pass through the second region 22. On the other hand, the smaller the distance w1, the more likely it is that ambient light incident on the first region 21 of the optical film 1 from a direction perpendicular to the vertical direction dv and reflected off the surface of the panel body 106 will pass through the same first region 21 from which it was incident. Furthermore, the larger the distance w1, the more likely it is that ambient light incident on the second region 22 of the optical film 1 and reflected off the surface of the panel body 106 will pass through the first region 21. On the other hand, the smaller the distance w1, the more likely it is that ambient light incident on the second region 22 of the optical film 1 from a direction perpendicular to the vertical direction dv and reflected off the surface of the panel body 106 will pass through the same second region 22 from which it was incident. By having a distance w1 of 120 μm or less, it becomes sufficiently difficult for ambient light incident on the first region 21 and reflected to pass through the second region 22, and for ambient light incident on the second region 22 and reflected to pass through the first region 21. In particular, the above effect can be fully obtained when the elevation angle θ of the observation direction d3 is within the range of angles that can be assumed as the elevation angle θ of the observation direction d3 of a normal image display panel 101. This allows the optical film 1 to fully exhibit the effect of reducing the emission of reflected light from the surface of the panel body 106 and the effect of neutralizing the color in the first region 21 and the color in the second region 22. By having a distance w1 of 1 μm or more, it is easier to handle from the standpoint of mass production.

[0162] In particular, the distance w1 is between 5 μm and 200 μm. This makes it sufficiently difficult for ambient light incident on the first region 21 and reflected to pass through the second region 22, and for ambient light incident on the second region 22 and reflected to pass through the first region 21, when the image display device 100 is an organic EL display device, based on the configuration of a typical organic EL display device. Furthermore, when the image display device 100 is a liquid crystal display device, it makes it sufficiently difficult for ambient light incident on the first region 21 and reflected to pass through the second region 22, and for ambient light incident on the second region 22 and reflected to pass through the first region 21, when the image display device 100 is a liquid crystal display device, based on the configuration of a typical liquid crystal display device.

[0163] <<Variation>> Next, various modifications of this embodiment will be described with reference to Figures 8 to 11. In Figures 8 to 11, the same reference numerals are used for parts that are the same as those shown in Figures 1A to 7C, and detailed descriptions are omitted. In Figures 8 to 11, the linear lines indicating the orientation direction of the liquid crystal compound in the liquid crystal layer 10 are omitted.

[0164] <Example 1> In the above-described embodiment, an example was given in which each of the multiple pattern regions 20 extends from one end to the other of the optical film 1 in the vertical direction dv. However, the form of the optical film 1 is not limited to this. As shown in Figure 8, in the optical film 1, each of the multiple pattern regions 20 does not have to extend from one end to the other of the optical film 1 in the vertical direction dv. In the optical film 1 shown in Figure 8, the multiple pattern regions 20 are aligned in the first direction d1 as well as in the vertical direction dv.

[0165] The second direction d2 is defined as follows: From among the directions perpendicular to the thickness direction dn and where the centroids GC1 and GC2 are aligned, we identify the direction in which the width of the gap region 23 is the second smallest after the first direction d1. In the examples shown in Figure 8, and later in Figures 9 and 10, directions dx and dy correspond to the directions perpendicular to the thickness direction dn and where the centroids GC1 and GC2 are aligned. In the examples shown in Figure 8, and later in Figures 9 and 10, the width of the gap region 23 in direction dx and the width of the gap region 23 in direction dy are equal. Both directions dx and dy correspond to the directions perpendicular to the thickness direction dn and where the centroids GC1 and GC2 are aligned, and in which the width of the gap region 23 is smallest. In this case, direction dx can be considered as the first direction d1 and direction dy as the second direction d2. On the other hand, it is also possible to consider direction dy as the first direction d1 and direction dx as the second direction d2. For convenience, in this specification, we will consider direction dx as the first direction d1 and direction dy as the second direction d2, and describe the optical film 1 shown in Figure 8, and later in Figures 9 and 10.

[0166] In the example shown in Figure 8, the second direction d2 coincides with the vertical direction dv. Therefore, in the optical film 1 shown in Figure 8, the multiple pattern regions 20 are aligned in both the first direction d1 and the second direction d2. Although not shown in the figure, the second direction d2 does not necessarily have to coincide with the vertical direction dv.

[0167] In the optical film 1 shown in Figure 8, the multiple first regions 21 and the multiple second regions 22 are arranged alternately in the second direction d2 as well. In other words, the pattern in which the first regions 21 and the second regions 22 are arranged in this order is repeated in the second direction d2 as well. Gap regions 23 are also provided between each of the multiple first regions 21 and the multiple second regions 22 in the second direction d2. In other words, the pattern in which the first region 21, gap region 23, second region 22 and gap region 23 are arranged in this order is repeated in the second direction d2 as well.

[0168] In the optical film 1 shown in Figure 8, the shapes of the first region 21 and the second region 22, when observed from the thickness direction dn of the optical film 1, are square. The width of the first region 21 in the first direction d1 is equal to the width of the first region 21 in the second direction d2. The width of the second region 22 in the first direction d1 is equal to the width of the second region 22 in the second direction d2. Although not shown in the figure, the first region 21 and the second region 22, which are rectangles rather than squares when observed from the thickness direction dn of the optical film 1, may be arranged alternately in the second direction d2.

[0169] Although not shown in the diagram, the shapes of the first region 21 and the second region 22 when observed from the thickness direction dn of the optical film 1 may be quadrilaterals that are neither squares nor rectangles. In this case, the shapes of the first region 21 and the second region 22 when observed from the thickness direction dn of the optical film 1 may be rhombuses, trapezoids, etc.

[0170] In an optical film 1 in which multiple pattern regions 20 are aligned in a first direction d1 and also in a second direction d2, the width of each of the multiple first regions 21 and multiple second regions 22 in the second direction d2 may be 45 μm or more. This allows the optical film 1 to fully exhibit an effect that reduces the emission of reflected light, similar to the effect of making the width of each of the first regions 21 and second regions 22 in the first direction d1 45 μm or more. Furthermore, it allows the optical film 1 to fully exhibit an effect that neutralizes the color of the first region 21 and the color of the second region 22. In particular, when ambient light is incident on the optical film 1 from a direction parallel to a plane parallel to the second direction d2 and the thickness direction dn, the effect of reducing the emission of reflected light and the effect of neutralizing the color of the first region 21 and the color of the second region 22 can be fully exhibited in the optical film 1.

[0171] In an optical film 1 in which multiple pattern regions 20 are aligned in a first direction d1 and also in a second direction d2, the width of the gap region 23 in the second direction d2 may be 140 nm or more and 4000 nm or less. This reduces the likelihood of disorder in the orientation of the liquid crystal compound in the liquid crystal layer 10 in the first region 21 and the second region 22, similar to the effect of setting the width of the gap region 23 in the first direction d1 to 140 nm or more and 4000 nm or less.

[0172] <Modification 2> In the embodiments and modifications described above, examples were given in which the shapes of the first region 21 and the second region 22, when observed from the thickness direction dn of the optical film 1, are rectangular or square. However, the shapes of the first region 21 and the second region 22 are not limited to these. In the example shown in Figure 9, the shapes of the first region 21 and the second region 22, when observed from the thickness direction dn of the optical film 1, are elliptical. In the example shown in Figure 10, the shapes of the first region 21 and the second region 22, when observed from the thickness direction dn of the optical film 1, are circular. Although not shown, the shapes of the first region 21 and the second region 22, when observed from the thickness direction dn of the optical film 1, may also be distorted circles.

[0173] In the examples shown in Figures 9 and 10, since the shapes of the first region 21 and the second region 22 are elliptical or circular, the width of the gap region 23 in one direction where the centroids GC1 and GC2 are aligned is different in the direction perpendicular to that direction. For example, in the example shown in Figure 9, the widths (w2, w3) of the gap region 23 in the direction dx where the centroids GC1 and GC2 are aligned are different in the direction dy perpendicular to direction dx. In this way, when the width of the gap region 23 in one direction where the centroids GC1 and GC2 are aligned is different in the direction perpendicular to that direction, the minimum value of the width is considered to be the width of the gap region 23 in that direction. In the example shown in Figure 9, the width of the gap region 23 in direction dx is considered to be width w2.

[0174] In the examples shown in Figures 9 and 10, since the shapes of the first region 21 and the second region 22 are elliptical or circular, the widths of the first region 21 and the second region 22 in one direction in which the centroids GC1 and GC2 are aligned are different in the direction perpendicular to that direction. For example, in the example shown in Figure 9, the widths (w4, w5) of the first region 21 in the direction dx in which the centroids GC1 and GC2 are aligned are different in the direction dy perpendicular to direction dx. In this way, when the widths of the first region 21 and the second region 22 in one direction in which the centroids GC1 and GC2 are aligned are different in the direction perpendicular to that direction, the maximum width is considered to be the width of the first region 21 and the second region 22 in that direction. In the example shown in Figure 9, the width of the first region 21 in direction dx is considered to be width w4.

[0175] In the modified example 2, the optical film 1 can also fully exhibit the effects of reducing the emission of reflected light and neutralizing the color in the first region 21 and the color in the second region 22.

[0176] <Variation 3> In the embodiments and modifications described above, the case where the first direction d1 is a linearly extending direction was explained. However, the first direction d1 is not limited to this. The first direction d1 may also be the radial direction da, which is the direction extending from the axis GC perpendicular to the thickness direction dn of the optical film 1 in a direction perpendicular to the axis GC. In the example shown in Figure 11, among the multiple pattern regions 20, the pattern region 20 that includes the portion through which the axis GC of the optical film 1 passes is a circular region. Among the multiple pattern regions 20, the pattern region 20 that does not include the portion through which the axis GC of the optical film 1 passes is an annular region surrounding the axis GC. In this case, the centroid GC1 of all the first regions 21 and the centroid GC2 of all the second regions 22 overlap at the position of the axis GC. In such a case, the multiple pattern regions 20 can be considered to be aligned in the radial direction da, which is the first direction d1, when observed from the thickness direction dn of the optical film 1.

[0177] In the optical film 1 shown in Figure 11, the multiple first regions 21 and the multiple second regions 22 are arranged alternately in the radial direction da. In other words, the pattern in which the first regions 21 and the second regions 22 are arranged in this order is repeated in the radial direction da. In the optical film 1 shown in Figure 11, the gap regions 23 are provided between each of the multiple first regions 21 and the multiple second regions 22 in the radial direction da. In other words, the pattern in which the first region 21, gap region 23, second region 22 and gap region 23 are arranged in this order is repeated in the radial direction da.

[0178] In the third modified example, the optical film 1 can still fully exhibit the effects of reducing the emission of reflected light and neutralizing the color in the first region 21 and the color in the second region 22.

[0179] <Modification 4> In the embodiments and modifications described above, an example was described in which the direction of the slow axis of the liquid crystal layer 10 in the first region 21 forms an angle of 45±5° with respect to the first direction d1, and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 forms an angle of -45±5° with respect to the first direction d1. However, the direction of the slow axis of the liquid crystal layer 10 is not limited to this. Figure 12 is a diagram showing a part of the optical film 1 of modification 4 as observed from the thickness direction dn of the optical film 1. The straight lines in the pattern region 20 in Figure 12 indicate the orientation direction of the liquid crystal compound of the liquid crystal layer 10. In the example shown in Figure 12, the direction of the slow axis of the liquid crystal layer 10 in the first region 21 does not form an angle of 45±5° with respect to the first direction d1. In the example shown in Figure 12, the angle that the direction of the slow axis of the liquid crystal layer 10 in the first region 21 makes with respect to the first direction d1 is 0°. In the example shown in Figure 12, the direction of the slow axis of the liquid crystal layer 10 in the second region 22 does not form an angle of -45±5° with respect to the first direction d1. In the example shown in Figure 12, the angle that the direction of the slow axis of the liquid crystal layer 10 in the second region 22 makes with respect to the first direction d1 is 90°. In the example shown in Figure 12, the angle difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 is between 80° and 100°.

[0180] With respect to the optical film 1 shown in Figure 12, a phase difference plate 60 that functions as an elliptical or circular polarizer can be fabricated by stacking the polarizer 61 on the liquid crystal layer 10 such that the angular difference between the direction of the absorption axis of the polarizer 61 and the direction of the slow axis of the liquid crystal layer 10 is close to 45°. In particular, a phase difference plate 60 that functions as an elliptical or circular polarizer can be fabricated by stacking the polarizer 61 on the liquid crystal layer 10 such that the angular difference between the direction of the absorption axis of the polarizer 61 and the direction of the slow axis of the liquid crystal layer 10 is 45°±5°. [Examples]

[0181] Next, specific examples for confirming the effects of the optical film 1 of this disclosure will be described.

[0182] (Examples 1 and 2, Comparative Example 1) Examples 1 and 2 and Comparative Example 1 were manufactured using the same method as shown in Table 1 below, except that the conditions were set accordingly.

[0183] Specifically, first, a substrate layer 40 made of cycloolefin polymer (COP) was prepared. Next, an orientation layer 50 was formed on the substrate layer 40. The orientation layer 50 was formed by the following method: An orientation film forming coating liquid containing a polymerizable acrylic resin, which is a UV-curable resin, was applied to the substrate layer 40 to form a layer containing the resin. Next, the layer containing the resin was shaped using a plate having a shape complementary to the surface shape of the orientation layer 50. Specifically, first, the plate was pressed against the layer containing the resin and cured by irradiation with ultraviolet light. After that, the plate was peeled off the layer containing the resin.

[0184] In forming the orientation layer 50, the surface shape of the orientation layer 50 was adjusted so that an optical film 1 is manufactured in which each of the multiple pattern regions 20 extends from one end to the other in the vertical direction dv, as shown in Figure 2. In particular, as shown in Figure 2, the surface shape of the orientation layer 50 was adjusted so that the shape of each of the multiple pattern regions 20, when observed from the thickness direction dn of the optical film 1, is rectangular. Specifically, the surface shape of the orientation layer 50 was adjusted so that the widths of the first region 21, the second region 22, and the gap region 23 in the first direction d1 are as shown in Table 1 described later.

[0185] Next, a liquid crystal layer 10 was laminated onto the alignment layer 50. In laminating the liquid crystal layer 10, first, a polymerizable liquid crystal composition for forming the liquid crystal layer 10 was applied to form a coating film. Next, the formed coating film of the polymerizable liquid crystal composition was heated to the phase transition temperature of the polymerizable liquid crystal composition to orient the liquid crystal compounds contained in the polymerizable liquid crystal composition. Subsequently, the coating film was dried. After that, the coating film was cooled to a temperature at which it could be solidified, and polymerization was carried out by a curing treatment. The curing treatment was performed by irradiating with ultraviolet light (photoirradiation treatment) to cure the liquid crystal compounds by a photopolymerization reaction. This curing treatment fixed the orientation direction of the liquid crystal compounds and obtained the liquid crystal layer 10. Thus, a liquid crystal layer 10 was formed on the alignment layer 50.

[0186] A composition comprising a liquid crystal compound, a photopolymerization initiator, a leveling agent, and a solvent was used for forming the liquid crystal layer 10. A polymerizable liquid crystal monomer was used as the liquid crystal compound in the composition for forming the liquid crystal layer 10. Omnirad 819 from IGM Resins BV was used as the photopolymerization initiator in the composition for forming the liquid crystal layer 10. BYK-361N from Bic Chemie Japan Co., Ltd. was used as the leveling agent in the composition for forming the liquid crystal layer 10. A mixture of cyclohexanone, 2-acetoxy-1-methoxypropane, and isobutyl acetate from Kanto Chemical Co., Ltd. was used as the solvent in the composition for forming the liquid crystal layer 10. The concentrations of cyclohexanone, 2-acetoxy-1-methoxypropane, and isobutyl acetate in the solvent were 20 wt%, 40 wt%, and 40 wt%, respectively. The liquid crystal solids content was adjusted to 20 wt% relative to the solvent. Regarding the amounts of photopolymerization initiator and leveling agent added, the photopolymerization initiator was added at 5 wt% relative to the liquid crystal solids content, and the leveling agent was added at 0.2 wt% relative to the liquid crystal solids content.

[0187] The angular difference between the direction of the slow axis of the liquid crystal layer 10 in the first region 21 and the direction of the slow axis of the liquid crystal layer 10 in the second region 22 was set to 90°. In the first region 21, the direction of the slow axis of the liquid crystal layer 10 was set to be at an angle of 45° with respect to the first direction d1. In the second region 22, the direction of the slow axis of the liquid crystal layer 10 was set to be at an angle of -45° with respect to the first direction d1.

[0188] Optical film 1 of Examples 1 and 2 and Comparative Example 1 were manufactured using the methods described above.

[0189] Next, a polarizing plate 61, which is a linear polarizing plate, was prepared. For the polarizing plate 61, a linear polarizing plate containing iodine-doped stretched PVA as the polarizer was used. Furthermore, a ZTAC® manufactured by Konica Minolta, Inc. was prepared. ZTAC® will be abbreviated as "ZTAC" below.

[0190] Next, the surface of the polarizing plate 61 and the surface of the ZTAC were joined via an adhesive layer. Furthermore, the surface of the ZTAC and the first surface 1a, which is composed of the liquid crystal layer 10 of the optical film 1, were joined via an adhesive layer. Then, the base layer 40 was peeled off from the parts of the optical film 1 other than the base layer 40. This exposed the surface of the alignment layer 50 of the optical film 1.

[0191] When joining the surface of the polarizing plate 61 to the surface of the ZTAC, and joining the surface of the ZTAC to the first surface 1a of the optical film 1, the orientation of the liquid crystal layer 10 and the polarizing plate 61 was adjusted so that the angle it made with respect to the first direction d1 of the absorption axis of the polarizing plate 61 was 90°.

[0192] The phase difference plates 60 of Examples 1 and 2 and Comparative Example 1 were manufactured using the method described above.

[0193] Next, the second surface 1b of the manufactured phase difference plate 60, which is composed of the alignment layer 50 of the optical film 1, and the glossy surface of commercially available aluminum foil, which has a glossy surface and a matte surface, were joined together via an adhesive layer.

[0194] Using the method described above, test specimens for Examples 1 and 2 and Comparative Example 1 were prepared, in which aluminum foil, adhesive layer, alignment layer 50, liquid crystal layer 10, adhesive layer, ZTAC, adhesive layer, and polarizing plate 61 were laminated in this order. In the prepared test specimens, the distance between the liquid crystal layer 10 and the aluminum foil was 5 μm.

[0195] The "Width of the First and Second Regions" in Table 1 indicates the width of the first region 21 and the second region 22 in the first direction d1. In Examples 1 and 2 and Comparative Example 1, the width of the first region 21 in the first direction d1 is equal to the width of the second region 22 in the first direction d1. The "Width of the Gap Region" in Table 1 indicates the width of the gap region 23 in the first direction d1.

[0196] [Table 1]

[0197] (Comparative Example 2) Except for the points described below, the optical film 1, phase difference plate 60, and test specimen of Comparative Example 2 were prepared in the same manner as in Example 1. In Comparative Example 2, instead of the liquid crystal layer 10, a liquid crystal layer was prepared in which the direction of the slow axis was uniform throughout the entire liquid crystal layer. The surface shape of the alignment layer 50 was adjusted so that such a liquid crystal layer could be prepared. In Comparative Example 2, when preparing the phase difference plate 60, the orientation of the liquid crystal layer and the polarizing plate 61 was adjusted so that the angle between the slow axis of the liquid crystal layer and the absorption axis of the polarizing plate 61 was 45°.

[0198] Brightness evaluation tests and color evaluation tests were performed on the test specimens of Examples 1 and 2 and Comparative Examples 1 and 2. In the brightness evaluation tests and color evaluation tests, for the test specimens of Examples 1 and 2 and Comparative Example 1, the azimuth angle ψ of the observation direction d3 perpendicular to the thickness direction dn and the first direction d1 was set to 0°, and the observation direction d3 was described accordingly. For the test specimen of Comparative Example 2, the azimuth angle ψ of the observation direction d3 perpendicular to the thickness direction dn and at an angle of 0° with respect to the absorption axis of the polarizing plate 61 was set to 0°, and the observation direction d3 was described accordingly. In this case, the observation direction d3 where the azimuth angle ψ is 0° forms an angle of 45° with respect to the slow axis of the liquid crystal layer.

[0199] (1) Brightness evaluation test In the brightness evaluation test, the test specimens of Examples 1 and 2 and Comparative Examples 1 and 2 were placed on a plane so that the surface formed by the polarizing plate 61 was the upper surface. Subsequently, the test specimens were photographed from multiple observation directions d3 so that a point on the upper surface of the test specimen was the center of the image. Specifically, with the azimuth angle ψ of observation direction d3 set to 0°, images were taken when the elevation angle θ was 30°, 40°, 50°, 60°, 70°, and 80°. Furthermore, with the azimuth angle ψ of observation direction d3 set to 90°, images were taken when the elevation angle θ was 30°, 40°, 50°, 60°, 70°, and 80°. A digital camera (Olympus Corporation, Tough TG-6 ISOA200 F2.0) was used to photograph the test specimens. The distance between the point on the upper surface of the test specimen that was considered the center of the image and the lens of the digital camera was set to 10 cm. The test specimens were photographed in a room with normal lighting conditions during the daytime.

[0200] Each image captured from multiple observation directions d3 was converted to 8-bit (grayscale) using the image processing software ImageJ (version 1.54g). The procedure for converting each image to 8-bit involved selecting the Image tab, then the Type tab, and finally selecting 8-bit. Furthermore, the average brightness value within the captured images was calculated using ImageJ. The procedure for calculating the average brightness value involved selecting the Analyze tab and then the Measure tab in ImageJ. The Mean value obtained through this procedure was used as the average brightness value. Additionally, the absolute difference in brightness between the case where the azimuth angle ψ is 0° and the case where the azimuth angle ψ is 90° was calculated for each of the elevation angles θ: 30°, 40°, 50°, 60°, 70°, and 80°. The results of calculating the absolute difference in brightness are shown in Table 2. Figure 13 shows graphs illustrating the change in the absolute difference in brightness when the elevation angle θ is varied in each of Examples 1 and 2 and Comparative Examples 1 and 2. The absolute values ​​of the luminance differences shown in Table 2 and Figure 13 are dimensionless quantities.

[0201] [Table 2]

[0202] (2) Color evaluation test In the color evaluation test, the test specimens of Examples 1 and 2 and Comparative Examples 1 and 2 were placed on a plane so that the surface formed by the polarizing plate 61 was the upper surface. Subsequently, the test specimens were photographed from multiple observation directions d3 so that a point on the upper surface of the test specimen was the center of the image. Specifically, images were taken when the elevation angle θ of the observation direction d3 was 60° and the azimuth angle ψ was 45° and -45°. The image capture conditions in the color evaluation test, other than the observation direction d3, were the same as the image capture conditions in the luminance evaluation test.

[0203] Each image captured from multiple observation directions d3 was converted into an RGB stack (separated into RGB images) using the image processing software ImageJ (version 1.54g). The procedure for converting each image into an RGB stack involved selecting the Image tab, then the Type tab, and finally selecting RGB Stack. Furthermore, using ImageJ, the average brightness of the R element in the captured image was calculated from the R element image within the separated RGB images. The procedure for calculating the average brightness involved selecting the Analyze tab and then the Measure tab in ImageJ. The Mean value obtained through this procedure was used as the average brightness. In addition, using ImageJ, the average brightness of the B element in the captured image was calculated from the B element image within the separated RGB images. The brightness values ​​for the R and B elements were represented by numbers ranging from 0 to 255.

[0204] Let R(45°) be the average brightness of the R element when the azimuth angle ψ of the observation direction d3 is 45°. Let R(-45°) be the average brightness of the R element when the azimuth angle ψ of the observation direction d3 is -45°. Let B(45°) be the average brightness of the B element when the azimuth angle ψ of the observation direction d3 is 45°. Let B(-45°) be the average brightness of the B element when the azimuth angle ψ of the observation direction d3 is -45°. From the calculated R(45°), R(-45°), B(45°), and B(-45°), the value ΔRB is calculated using the following equation (1). The value ΔRB represents the magnitude of the difference between the color observed when the elevation angle θ of the observation direction d3 is 60° and the azimuth angle ψ is 45°, and the color observed when the elevation angle θ of the observation direction d3 is 60° and the azimuth angle ψ is -45°. A larger value ΔRB indicates a larger change in the observed color when the azimuth angle ψ is changed from 45° to -45°. A smaller value ΔRB indicates a smaller change in the observed color when the azimuth angle ψ is changed from 45° to -45°. Furthermore, the value |ΔR| was calculated. The value |ΔR| is the absolute value of the difference between R(45°) and R(-45°). Furthermore, the value |ΔB| was calculated. The value |ΔB| is the absolute value of the difference between B(45°) and B(-45°).

number

[0205] Table 3 shows the calculation results for R(45°), R(-45°), value |ΔR|, B(45°), B(-45°), value |ΔB|, and value ΔRB.

[0206] [Table 3]

[0207] From Table 2 and Figure 13, it was found that in Examples 1 and 2, where the width of the first region 21 and the second region 22 in the first direction d1 is 120 μm or 80 μm, the absolute value of the difference in brightness between when the azimuth angle ψ is 0° and when the azimuth angle ψ is 90° can be made relatively small. In particular, it was found that the absolute value of the difference in brightness can be made relatively small even when the elevation angle θ is relatively small. In contrast, in Comparative Example 1, where the width of the first region 21 and the second region 22 in the first direction d1 is 40 μm, it was found that the absolute value of the difference in brightness can be made relatively large. In particular, it was found that the absolute value of the difference in brightness can be made relatively large when the elevation angle θ is relatively small. In particular, in the range of elevation angle θ from 30° to 50°, it was found that the absolute value of the difference in brightness can be made significantly smaller in Examples 1 and 2 compared to Comparative Example 1.

[0208] Table 3 shows that in Examples 1 and 2, where the optical film 1 has a first region 21 and a second region 22, the value ΔRB can be significantly reduced compared to Comparative Example 2, where the optical film 1 does not have a first region 21 and a second region 22.

[0209] The results of the brightness evaluation test and the color evaluation test showed that in Examples 1 and 2, the difference in appearance depending on the viewing direction of the optical film 1 was kept to a minimum compared to Comparative Examples 1 and 2.

[0210] To further confirm the effects of the optical film 1 of this disclosure, optical films 1 of Examples 3-8 and Comparative Examples 3 and 4 were prepared.

[0211] (Examples 3-8, Comparative Examples 3, 4) For Examples 3-8 and Comparative Examples 3 and 4, optical film 1 was manufactured in the same manner as in Example 1, except that the conditions were set as shown in Table 4 below.

[0212] Table 4's "Width of First and Second Regions" indicates the width of the first region 21 and the second region 22 in the first direction d1. In Examples 3-8 and Comparative Examples 3 and 4, the width of the first region 21 in the first direction d1 is equal to the width of the second region 22 in the first direction d1. Table 1's "Width of Gap Region" indicates the width of the gap region 23 in the first direction d1. A value of "0" in the "Width of Gap Region" column means that the gap region 23 is not included in the multiple pattern regions 20, and that the first region 21 and the second region 22 are in contact with each other.

[0213] [Table 4]

[0214] Microscopic surface observation and evaluation tests were performed on optical film 1 of Examples 3-8 and Comparative Examples 3 and 4.

[0215] (3) Surface observation and evaluation test using a microscope In the surface observation evaluation test using a microscope, the surface of the liquid crystal layer 10 formed in the fabrication of optical film 1 in Examples 3-8 and Comparative Examples 3 and 4 was observed.

[0216] The surface of the liquid crystal layer 10 was observed using a microscope under the following conditions. A polarizing optical microscope (product name "BX51-P", manufactured by Olympus Corporation) was used to select a clean, wrinkle-free area of ​​the optical film 1 and observe the surface at a magnification of 100x. Then, it was evaluated whether or not any disorder in the orientation of the liquid crystal compounds in the liquid crystal layer 10 was observed in the first region 21 and the second region 22. Specifically, if straight lines were observed at the boundary between the first region 21 and the gap region 23, and between the second region 22 and the gap region 23, and if the orientation defects observed in the first region 21 accounted for 30% or less of the total area of ​​the first region 21, and the orientation defects observed in the second region 22 accounted for 30% or less of the total area of ​​the second region 22, then it was evaluated that no disorder in orientation was observed. If the above conditions were not met, it was evaluated that disorder in orientation was observed.

[0217] In Table 4, "None" in the "Orientation Disorder" column means that no orientation disorder was observed. In Table 4, "Present" in the "Orientation Disorder" column means that orientation disorder was observed. Figure 14A shows an image of the surface of the liquid crystal layer 10 taken in the microscopic surface observation evaluation test of optical film 1 of Example 3. Figure 14B shows an image of the surface of the liquid crystal layer 10 taken in the microscopic surface observation evaluation test of optical film 1 of Comparative Example 3.

[0218] Table 4, Figure 14A, and Figure 14B show that no orientation disorder was observed in the optical film 1 of Example 3-8, which has a gap region 23. In contrast, orientation disorder was observed in the optical film 1 of Comparative Examples 3 and 4, which do not have a gap region 23. From the above, it was found that by providing a gap region 23, orientation disorder can be made less likely to occur in the liquid crystal layer 10 of the optical film 1.

[0219] The multiple components disclosed in the above embodiments and each of their variations can be combined as needed. Alternatively, some components may be removed from all the components shown in the above embodiments and each of their variations. [Explanation of Symbols]

[0220] 1 Optical film 20 Pattern Areas 21 First area 22 Second area 23 Interstitial area 40 Base material layer 50 orientation layer 51 Uneven shape 60 Retardation plate 61 Polarizing plate 100 Image Display Devices 101 Image display panel 106 Panel Body

Claims

1. An optical film comprising a liquid crystal layer, The optical film, when observed from the thickness direction of the optical film, includes a plurality of pattern regions aligned in a first direction perpendicular to the thickness direction, The plurality of pattern regions include a plurality of first regions and a plurality of second regions, and the plurality of first regions and the plurality of second regions are arranged alternately in the first direction. The angular difference between the direction of the phase-lagging axis of the liquid crystal layer in the first region and the direction of the phase-lagging axis of the liquid crystal layer in the second region is 80° or more and 100° or less. The width of each of the plurality of first regions and the plurality of second regions in the first direction is 45 μm or more and 240 μm or less. An optical film in which the plurality of pattern regions further include gap regions provided between each of the plurality of first regions and the plurality of second regions.

2. In the first region, the direction of the phase-lagging axis of the liquid crystal layer is at an angle of 45° with respect to the first direction. The optical film according to claim 1, wherein in the second region, the direction of the slow axis of the liquid crystal layer forms an angle of -45° with respect to the first direction.

3. The optical film according to claim 1, wherein the width of the gap region in the first direction is 140 nm or more and 4000 nm or less.

4. Further equipped with an orientation layer, The optical film according to claim 1, wherein the liquid crystal layer is laminated on the alignment layer.

5. The optical film according to claim 4, wherein at least an uneven shape is formed on the surface of the alignment layer on which the liquid crystal layer is laminated.

6. The optical film according to claim 4, wherein the orientation layer contains a component having a functional group that generates photoreactivity.

7. An optical film according to any one of claims 1 to 6, A phase difference plate comprising: a polarizing plate superimposed on the optical film such that the angle the absorption axis makes with respect to the first direction is 0°±5° or 90°±5°; and a phase difference plate.

8. An image display panel comprising the phase difference plate described in claim 7.

9. The panel itself is further equipped, The phase difference plate is placed on the panel body, The image display panel according to claim 8, wherein the distance between the liquid crystal layer and the panel body is 1 μm or more and 120 μm or less.

10. An image display device comprising the phase difference plate described in claim 7.

11. The panel itself is further equipped, The phase difference plate is placed on the panel body, The image display device according to claim 10, wherein the distance between the liquid crystal layer and the panel body is 1 μm or more and 120 μm or less.

Images