Sheet and method for manufacturing liquid crystal optical element

Abstract

The present invention addresses the problem of providing a sheet capable of improving the uniformity of the quality of a liquid crystal optical element produced by a batch process. The present invention also addresses the problem of providing a method for manufacturing a liquid crystal optical element. This sheet has a liquid crystal layer containing a liquid crystal compound, and is characterized in that the liquid crystal layer has a plurality of liquid crystal alignment pattern regions each having a liquid crystal alignment pattern in which the orientation derived from the optical axis of the liquid crystal compound changes while continuously rotating in at least one direction in the plane. The plurality of liquid crystal alignment pattern regions are disposed apart from each other along two directions orthogonal in the plane of the liquid crystal layer with a non-alignment region therebetween, two or more liquid crystal alignment pattern regions are disposed in each of the two directions in the liquid crystal layer, the non-alignment region is a region having no liquid crystal alignment pattern or a slow axis, and the non-alignment region is a region having no liquid crystal alignment pattern or slow axis. The outer periphery of the liquid crystal alignment pattern region is surrounded by an outer peripheral region which does not have a liquid crystal alignment pattern and has a slow axis, and a specific region including the liquid crystal alignment pattern region can be cut into a liquid crystal optical element.

Description

Technical Field

[0001] The invention relates to a sheet material and a method for manufacturing a liquid crystal optical element. Background Art

[0002] Optical elements that control the direction of light are used in many optical devices or systems.

[0003] For example, optical elements that control the direction of light are used in various optical devices, such as backlights of liquid crystal displays, AR (Augmented Reality) glasses, VR (Virtual Reality) glasses, and MR (Mixed Reality) glasses that display virtual images and various information on top of the actual scene, head-mounted displays (HMD (Head Mounted Display)), heads-up displays (HUD (Head Up Display)), projectors, beam redirectors, and sensors for detecting objects and measuring the distance to objects.

[0004] As such an optical element for controlling the direction of light, there has been proposed a liquid crystal optical element which is formed using a liquid crystal composition containing a liquid crystal compound and has a liquid crystal layer exhibiting optical anisotropy.

[0005] Patent document 1 describes an optical element, which includes a birefringent material layer having a local optical axis direction that changes in at least one direction along its surface, the local optical axis direction corresponding to an optical axis direction profile formed by changing the polarization of light from a light source between multiple polarizations, focusing the light from the light source into a spot at a focal plane, and scanning the spot in at least two dimensions along the surface of a polarization-sensitive recording medium arranged close to the focal plane so that adjacent scans substantially overlap, and the change of the polarization and the scanning of the spot are performed independently.

[0006] Patent document 2 describes an optical element having a plurality of stacked birefringent sublayers configured to change the propagation direction of light passing therethrough according to the Bragg condition, wherein each of the stacked birefringent sublayers has a local optical axis that changes along each interface between adjacent objects in the stacked birefringent sublayers to define a corresponding grating period. Patent document 2 describes an optical element that diffracts transmitted light, diffracts light incident on a substrate (light guide plate) by using the optical element, causes the light to enter the substrate at an angle of total reflection in the substrate, and guides the light in the substrate in a direction substantially perpendicular to the incident direction of the light.

[0007] Especially when these optical elements are used as near-eye displays, their size ranges from a few mm square to a maximum of 5 cm square or a diameter of about 5 cm.

[0008] Previous technical literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application No. 2015-532468

[0011] Patent Document 2: Japanese Patent Application No. 2017-522601 Summary of the invention

[0012] Technical issues to be solved by the invention

[0013] Conventionally, as liquid crystal optical elements using liquid crystal materials, phase difference plates and optical compensation plates are known, and a method for mass production of these liquid crystal optical elements in a short time with stable quality using a roll-to-roll process has been established. However, in the case of liquid crystal optical elements used in the above optical devices, it is difficult to apply the conventional roll-to-roll process to manufacture the liquid crystal optical elements due to the complex optical design.

[0014] The method of manufacturing liquid crystal optical elements one by one by a batch process can also cope with complex optical designs. However, in the method of manufacturing liquid crystal optical elements of about 5 cm square or less in size by a batch process, there are problems not only in mass production but also in the uniformity of the quality of the manufactured liquid crystal optical elements.

[0015] The present invention aims to solve the problems of the prior art and provide a sheet material capable of improving the uniformity of the quality of a liquid crystal optical element manufactured by a batch process. In addition, the present invention aims to provide a method for manufacturing a liquid crystal optical element.

[0016] Means for solving technical problems

[0017] In order to solve the problem, the present invention has the following structure.

[0018] [1] A sheet material comprising a liquid crystal layer containing a liquid crystal compound, wherein the liquid crystal layer comprises a plurality of liquid crystal orientation pattern regions, the liquid crystal orientation pattern regions comprising a liquid crystal orientation pattern in which the direction of an optical axis of the liquid crystal compound changes while continuously rotating along at least one direction within a plane, the plurality of liquid crystal orientation pattern regions are arranged separately from each other along two directions orthogonal to each other within the plane of the liquid crystal layer, respectively separated by non-oriented regions, in the liquid crystal layer, two or more liquid crystal orientation pattern regions are arranged in each of the two directions, the non-oriented region is a region that does not have either the liquid crystal orientation pattern or a slow axis, the periphery of the liquid crystal orientation pattern region is surrounded by a peripheral region, the peripheral region is a region that does not have the liquid crystal orientation pattern and has a slow axis, and a specific region including the liquid crystal orientation pattern region can be cut out as a liquid crystal optical element.

[0019] [2] The sheet material according to [1], wherein:

[0020] The outer periphery of the liquid crystal alignment pattern region includes a straight portion and a curved portion, and a minimum curvature radius of the curved portion is greater than or equal to 0.2 mm.

[0021] [3] The sheet material according to [2], wherein:

[0022] At least one alignment mark indicating the periphery of the specific region or the optical center of the liquid crystal alignment pattern region is provided in the non-aligned region.

[0023] [4] The sheet material according to any one of [1] to [3], wherein

[0024] The specific region is constituted by the liquid crystal alignment pattern region and a part of the outer peripheral region.

[0025] [5] The sheet according to any one of [1] to [4], further comprising a support that supports the liquid crystal layer.

[0026] [6] A method for producing a liquid crystal optical element, comprising the step of cutting a specific region including the liquid crystal alignment pattern region from the sheet according to any one of [1] to [5].

[0027] [7] The method for manufacturing a liquid crystal optical element according to [6], wherein:

[0028] In the above step, the specific region is cut out by cutting the sheet along a cutting line including a straight portion and a curved portion, and the minimum curvature radius of the curved portion is 0.2 mm or more.

[0029] [8] The method for manufacturing a liquid crystal optical element according to [7], wherein:

[0030] The cutting line is included in any one of the peripheral region and the non-oriented region.

[0031] [9] The method for manufacturing a liquid crystal optical element according to [7] or [8], wherein:

[0032] The above-mentioned cutting line is included only in the above-mentioned outer peripheral area.

[0033] Effects of the Invention

[0034] According to the present invention, it is possible to provide a sheet material capable of improving the uniformity of the quality of a liquid crystal optical element manufactured by a batch process. In addition, according to the present invention, it is possible to provide a method for manufacturing a liquid crystal optical element. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a plan view showing an example of the structure of the sheet of the present invention.

[0036] Figure 2 This is a plan view showing an example of the structure of the liquid crystal alignment pattern region included in the sheet of the present invention.

[0037] Figure 3 This is a conceptual diagram showing an example of an image obtained by observing the liquid crystal alignment pattern region included in the sheet of the present invention with an optical microscope.

[0038] Figure 4 This is a plan view showing another example of the structure of the sheet of the present invention.

[0039] Figure 5 This is a conceptual diagram of an example of an exposure device for exposing an alignment film to form an alignment pattern.

[0040] Figure 6 This is a conceptual diagram of another example of an exposure device for exposing an alignment film to form an alignment pattern. DETAILED DESCRIPTION

[0041] Hereinafter, the sheet material and the method for producing a liquid crystal optical element of the present invention will be described in detail based on the preferred embodiments shown in the drawings.

[0042] In the present specification, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0043] In this specification, "in-plane" is used to mean "the inside of a plane parallel to the surface (main surface) of a sheet or liquid crystal optical element". In addition, "(any) direction in the plane" is used to mean "(any) direction parallel to the surface (main surface) of a sheet or liquid crystal optical element".

[0044] In this specification, visible light is light of a wavelength observable by the naked eye among electromagnetic waves, and refers to light in the wavelength region of 380 to 780 nm. Invisible light is light in the wavelength region of less than 380 nm and the wavelength region of more than 780 nm.

[0045] In this specification, Re(λ) represents the in-plane retardation at a wavelength λ. Unless otherwise specified, the wavelength λ is 550 nm.

[0046] In this specification, Re(λ) is a value measured at a wavelength of λ by AxoScan (manufactured by Axometrics). The average refractive index ((nx+ny+nz) / 3) and the film thickness (d (μm)) are input into AxoScan to calculate

[0047] Slow axis direction (°)

[0048] Re(λ)=R0(λ).

[0049] In addition, R0(λ) is expressed as a numerical value calculated by AxoScan, and refers to Re(λ).

[0050] [Sheet]

[0051] Figure 1 An example of the structure of the sheet of the present invention is conceptually shown in FIG. Figure 1 This is a plan view of the sheet 1 of the present invention as viewed from the normal direction of the surface (main surface).

[0052] exist Figure 1 In the figure, the direction indicated by the arrow X and the direction indicated by the arrow Y are both directions in the plane of the sheet 1 and are orthogonal to each other. Hereinafter, the direction indicated by the arrow X and the direction indicated by the arrow Y are also described as "X direction" and "Y direction", respectively.

[0053] Figure 1 The sheet 1 of the present invention shown has a liquid crystal layer 10 containing a liquid crystal compound.

[0054] The liquid crystal layer 10 has a plurality of liquid crystal alignment pattern regions 12. Here, the liquid crystal alignment pattern regions 12 have a liquid crystal alignment pattern (hereinafter also simply referred to as "liquid crystal alignment pattern") in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating in at least one direction in the plane.

[0055] These multiple liquid crystal alignment pattern regions 12 are separated from each other via non-aligned regions 16 along the X and Y directions perpendicular to each other in the plane of the liquid crystal layer 10. The non-aligned regions 16 are regions that do not have either a liquid crystal alignment pattern or a slow axis.

[0056] In the liquid crystal layer 10 , two or more liquid crystal alignment pattern regions 12 are arranged in each of the X direction and the Y direction.

[0057] The periphery of the liquid crystal alignment pattern region 12 is surrounded by an outer peripheral region 14. The outer peripheral region 14 is a region having no liquid crystal alignment pattern and having a slow axis.

[0058] exist Figure 1 The liquid crystal layer 10 of the sheet 1 shown has a specific region 18 including a liquid crystal orientation pattern region 12. The specific region 18 is configured to be cut out as a liquid crystal optical element. In the sheet 1, the periphery of the specific region 18 is formed by cutting lines X1 to X4 and Y1 to Y4. By cutting the sheet 1 along these cutting lines X1 to X4 and Y1 to Y4, a liquid crystal optical element corresponding to the specific region 18 can be obtained.

[0059] As shown in the figure, the liquid crystal layer 10 of the sheet 1 of the present invention is respectively provided with two or more liquid crystal orientation pattern regions 12 in the X direction and the Y direction which are orthogonal to each other. That is, the sheet 1 of the present invention has at least four or more liquid crystal orientation pattern regions 12. In addition, the number of liquid crystal orientation pattern regions possessed by the sheet of the present invention can be four or more, and there is no particular limitation.

[0060] In this way, by configuring a plurality of liquid crystal orientation pattern regions 12 that function as optically anisotropic layers on the same surface of the sheet 1 and being able to be cut into specific regions 18 for liquid crystal optical elements, a plurality of liquid crystal optical elements can be manufactured from the same sheet at once. That is, the sheet 1 of the present invention is used as a multi-sided sheet for liquid crystal optical elements. Compared with the case where a sheet including a separate optically anisotropic layer is formed each time in order to manufacture each liquid crystal optical element, when a plurality of liquid crystal optical elements are manufactured using the sheet 1 of the present invention, the thickness and quality of the optically anisotropic layer of the manufactured liquid crystal optical elements become the same even in a batch process, thereby suppressing quality deviations. Furthermore, the temperature, humidity, pressure and light conditions based on the processing through which the plurality of liquid crystal optical elements formed by the sheet 1 of the present invention pass are also consistent, and a product with constant and stable quality can be provided.

[0061] Furthermore, the sheet 1 of the present invention has a plurality of liquid crystal alignment pattern regions 12 arranged in two orthogonal directions, and can be cut more efficiently when the specific region 18 including the liquid crystal alignment pattern region 12 is cut to obtain each liquid crystal optical element.

[0062] Furthermore, in the sheet material 1 of the present invention, if Figure 1As shown, a plurality of liquid crystal orientation pattern regions 12 are arranged separately from each other via a peripheral region 14 and a non-oriented region 16. By such an arrangement, a space is created for passing through a cutting line when a specific region 18 is cut into individual leaf bodies as a liquid crystal optical element, so that the liquid crystal orientation pattern that functions as a liquid crystal optical element can be maintained without damaging stable quality.

[0063] Moreover, in the sheet 1 of the present invention, the periphery of each liquid crystal orientation pattern region 12 is surrounded by a peripheral region 14. Thus, compared with a sheet in which no peripheral region is provided around the liquid crystal orientation pattern region and only a non-oriented region is arranged between the two closest liquid crystal orientation pattern regions, the quality and uniformity of the liquid crystal optical element cut from the same sheet can be improved. In the case where no peripheral region is provided around the liquid crystal orientation pattern region, the liquid crystal compound is randomly oriented in the non-oriented region, so the orientation of the liquid crystal compound is disordered in the region near the periphery in contact with the non-oriented region in the liquid crystal orientation pattern region, and the desired optical properties cannot be obtained. In contrast, although the liquid crystal compound included in the peripheral region 14 is not regularly arranged to form a liquid crystal orientation pattern, the orientation order is maintained to the extent of having a slow axis, because the orientation disorder of the liquid crystal compound in the region near the periphery in contact with the peripheral region 14 of the liquid crystal orientation pattern region 12 can be suppressed, and a regular liquid crystal orientation pattern can be maintained.

[0064] Hereinafter, the structure of the sheet of the present invention will be described in more detail.

[0065] In the following description, unless otherwise specified, the term "liquid crystal optical element" means "a liquid crystal optical element produced by cutting out the above-mentioned specific region including a liquid crystal orientation pattern from the sheet of the present invention".

[0066] 〔Liquid crystal orientation pattern area〕

[0067] The liquid crystal alignment pattern region 12 has a liquid crystal alignment pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating in at least one direction in the plane. A plurality of liquid crystal alignment pattern regions 12 are formed on the liquid crystal layer 10 .

[0068] Figure 1 The outer periphery of the liquid crystal alignment pattern region 12 shown is composed of four straight line portions and four curved line portions.

[0069] like Figure 1 As shown, by including straight and curved portions in the periphery of the liquid crystal orientation pattern region, the liquid crystal compound can be smoothly oriented along the periphery compared to the case where the periphery is formed only by straight portions, thereby suppressing the occurrence of orientation defects in the liquid crystal orientation pattern that functions as an optically anisotropic layer.

[0070] The minimum curvature radius of the curved portion is preferably 0.2 mm or more, more preferably 0.4 mm or more. The upper limit is not particularly limited, but is, for example, 20 mm or less, preferably 10 mm or less.

[0071] Figure 1 The periphery of the liquid crystal orientation pattern area 12 shown has a shape in which curved portions formed by fan-shaped arcs are formed at the four vertices of the quadrilateral, but the shape of the liquid crystal orientation pattern area possessed by the liquid crystal layer in the sheet of the present invention is not limited to the above-mentioned shape, and may be, for example, a circle, an ellipse, a polygon including a quadrilateral, and a shape in which at least a portion of the vertices of the polygon are replaced by a curve, etc.

[0072] Figure 2 1 and 2 conceptually show an example of the structure of the liquid crystal alignment pattern region of the sheet of the present invention.

[0073] Figure 2 The liquid crystal orientation pattern region 12 shown is one of a plurality of liquid crystal orientation pattern regions 12 arranged on the liquid crystal layer 10 of the sheet of the present invention. In the liquid crystal optical element formed by cutting out a specific region including the liquid crystal orientation pattern region 12 from the sheet of the present invention, the liquid crystal orientation pattern region 12 functions as an optically anisotropic layer. Figure 2 The liquid crystal optical element formed by the specific area of ​​the liquid crystal alignment pattern area 12 shown shows the function of the optical anisotropic layer to diffract the incident light, and is therefore also called a liquid crystal diffraction element.

[0074] The liquid crystal alignment pattern region 12 is formed using a composition containing a liquid crystal compound, and has a predetermined liquid crystal alignment pattern in which an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one direction in a plane.

[0075] exist Figure 2 In the example shown, the liquid crystal orientation pattern region 12 has a radial liquid crystal orientation pattern in which one direction (directions indicated by arrows A1 to A3, respectively) in which the direction of the optical axis of the liquid crystal compound 40 changes while continuously rotating is radially present along the direction from the inside to the outside. In this liquid crystal orientation pattern, a line connecting liquid crystal compounds whose optical axes face the same direction is circular, and a plurality of line segments forming a circle are arranged in a concentric circle.

[0076] exist Figure 2 In the illustrated liquid crystal alignment pattern region 12 , the optical axis originating from the liquid crystal compound 40 is the longitudinal direction of the liquid crystal compound 40 .

[0077] exist Figure 2In the liquid crystal orientation pattern region 12 shown, the direction of the optical axis originating from the liquid crystal compound 40 changes while continuously rotating along multiple directions from the center of the liquid crystal orientation pattern region 12 toward the outside, for example, the direction indicated by arrow A1, the direction indicated by arrow A2, and the direction indicated by arrow A3. Arrow A1, arrow A2, and arrow A3 are arrangement axes described later.

[0078] The liquid crystal orientation pattern of the liquid crystal orientation pattern region 12 has the following effect: the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane, and when the light incident on the liquid crystal optical element passes through the liquid crystal orientation pattern region 12, the azimuth direction of the light is diffracted (bent) along the above one direction. This diffraction effect in the liquid crystal orientation pattern depends on the length (period Λ) of the direction of the optical axis derived from the liquid crystal compound rotating 180° in the plane, and the shorter the period Λ, the larger the diffraction angle.

[0079] exist Figure 2 In the example shown, the liquid crystal orientation pattern area 12 has a radial liquid crystal orientation pattern. Therefore, when a liquid crystal orientation pattern is formed along each arrangement axis (A1 to A3, etc.) so as to diffract toward the center side in the azimuth direction of the incident light, the transmitted light of the liquid crystal optical element can be gathered. Alternatively, when a liquid crystal orientation pattern is formed along each arrangement axis (A1 to A3) so as to diffract toward the outside in the azimuth direction of the incident light, the transmitted light of the liquid crystal optical element can be diverged. Whether the transmitted light is diffracted along the center side or toward the outside depends on the polarization state of the incident light and the rotation direction of the optical axis in the liquid crystal orientation pattern.

[0080] Furthermore, the period Λ of the liquid crystal alignment pattern in the liquid crystal alignment pattern region 12 gradually changes along one direction. Figure 2 In the example shown, the period Λ of the liquid crystal alignment pattern changes so as to gradually become shorter from the center toward the outside.

[0081] As described above, the liquid crystal orientation pattern region 12 formed using a composition containing a liquid crystal compound and having a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along the arrangement axis direction diffracts light, but the smaller the period Λ of the liquid crystal orientation pattern, the larger the diffraction angle. Therefore, when the liquid crystal orientation pattern is formed in a manner with different periods Λ in different regions within the plane, light incident on different regions within the plane is diffracted at different angles.

[0082] For example, Figure 2In the example shown, when the liquid crystal orientation pattern of the liquid crystal orientation pattern region 12 is radial, by shortening the period Λ of the liquid crystal orientation pattern from the center side toward the outside of the liquid crystal orientation pattern region 12, in the liquid crystal optical element, it is possible to make the diffraction of light incident on the outer end side than the light incident near the center of the liquid crystal orientation pattern region 12 larger. The liquid crystal optical element having such a liquid crystal orientation pattern preferably functions as a condensing lens for condensing light, for example.

[0083] The presence or absence and shape of the liquid crystal alignment pattern region in the liquid crystal layer can be confirmed by observing the liquid crystal layer using an optical microscope.

[0084] Figure 3 1 and 2 conceptually show an example of an image obtained by observing the liquid crystal alignment pattern region of the sheet of the present invention with an optical microscope. Figure 3 The conceptual diagram shown is equivalent to observing with an optical microscope Figure 2 An image obtained by the liquid crystal alignment pattern region 12 of the liquid crystal layer 10 shown.

[0085] like Figure 3 As shown, in the observation image of the liquid crystal orientation pattern region 12 obtained using an optical microscope, a stripe pattern consisting of alternating bright lines 42 and dark lines 44 appears. It can be said that in the region where such a stripe pattern is observed, a liquid crystal orientation pattern is formed in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane.

[0086] On the other hand, in a region where no liquid crystal orientation pattern is formed (for example, the peripheral region and non-oriented region of the sheet of the present invention), no stripe pattern consisting of bright and dark lines appears in an observation image obtained using an optical microscope.

[0087] By the above method, in the liquid crystal layer included in the sheet of the present invention, the liquid crystal alignment pattern region and the region other than the liquid crystal alignment pattern region (peripheral region and non-aligned region) can be distinguished.

[0088] [Peripheral area]

[0089] The peripheral region 14 is a region having no liquid crystal alignment pattern and having a slow axis. The liquid crystal compounds included in the peripheral region 14 are not regularly aligned like the liquid crystal compounds included in the liquid crystal alignment pattern region 12, but are aligned in a direction approximately close to the alignment direction of the surrounding liquid crystal compounds.

[0090] exist Figure 1In the sheet material 1 (liquid crystal layer 10) shown, the peripheral region 14 is arranged to surround each of the plurality of liquid crystal orientation pattern regions 12. That is, in the liquid crystal layer 10, the plurality of peripheral regions 14, which are edge portions surrounding the liquid crystal orientation pattern regions 12, are arranged separately from each other along the X direction and the Y direction orthogonal to the plane, with the non-oriented region 16 interposed therebetween, and two or more peripheral regions 14 are arranged in each of the X direction and the Y direction.

[0091] The presence or absence of the peripheral region in the liquid crystal layer can be confirmed by the following method.

[0092] The laminate formed by configuring the sheet between 2 polarizers configured with orthogonal Nicols is observed by polarized light microscope. At this time, the laminate is observed while rotating the sheet in the plane. Through this observation, when the sheet rotates 90 ° each time, the region where the phenomenon of the bright field with the maximum brightness and the dark field with the minimum brightness repeatedly appearing can be said to be the region with the slow axis (birefringence).

[0093] In addition, when the liquid crystal orientation pattern area of ​​the sheet of the present invention is observed by the above method, a rainbow stripe pattern is observed whose brightness does not change during the rotation of the sheet. In addition, when the non-oriented area of ​​the sheet of the present invention is observed by the above method, an image that is uniformly bright in the plane and whose brightness does not change during the rotation of the sheet is observed.

[0094] By comparing the observation results of the area having a liquid crystal orientation pattern using an optical microscope with the observation results of the area having the above-mentioned slow axis, it is possible to confirm whether there is an area without a liquid crystal orientation pattern and having a slow axis on the periphery of the area having the liquid crystal orientation pattern, thereby confirming the presence or absence of the peripheral area possessed by the sheet of the present invention.

[0095] The peripheral area surrounding the liquid crystal orientation pattern area can be obtained, for example, in the following manner: when the photo-orientation material included in the orientation film used to form the liquid crystal layer is oriented by polarized light irradiation, an opening portion having a shape corresponding to the liquid crystal orientation pattern area is formed, and a liquid crystal layer is formed using an orientation film formed by irradiating polarized light through a mask separated from the orientation film.

[0096] Furthermore, it is also possible to obtain an alignment film capable of forming the peripheral region by adjusting the polarization degree and / or the amount of irradiated light of the alignment film corresponding to the peripheral region, and to form a liquid crystal layer using the alignment film to obtain the peripheral region.

[0097] 〔No orientation region〕

[0098] The non-oriented region 16 is a region having no liquid crystal orientation pattern and no slow axis. That is, the liquid crystal compound included in the non-oriented region 16 is not aligned, and the direction of the optical axis derived from the liquid crystal compound is random.

[0099] exist Figure 1 In the sheet 1 (liquid crystal layer 10) shown, the non-oriented region 16 is formed by a plurality of band-shaped regions extending respectively in the X direction and the Y direction. The liquid crystal orientation pattern region 12 is separated from other liquid crystal orientation pattern regions 12, and the peripheral region 14 is separated from other peripheral regions 14, whereas the non-oriented region 16 is continuous.

[0100] The presence or absence of the non-oriented region in the liquid crystal layer can be confirmed by the above-mentioned method for confirming the liquid crystal orientation pattern region and the above-mentioned method for confirming the peripheral region. The non-oriented region is a region where no stripe pattern showing the liquid crystal orientation pattern is observed even when observed by the above-mentioned method for confirming the liquid crystal orientation pattern region, and where an image is observed that is uniformly bright in the plane and does not change in brightness even when the sheet is rotated when observed by the above-mentioned method for confirming the peripheral region.

[0101] The non-aligned region surrounding the peripheral region in the liquid crystal layer can be formed by, for example, setting the irradiation range so that the region of the alignment film corresponding to the non-aligned region is not irradiated with polarized light when irradiating the alignment film for forming the liquid crystal layer with polarized light.

[0102] An alignment mark serving as a mark indicating a predetermined position may be provided in the non-oriented region.

[0103] As the alignment mark, for example, a mark indicating the periphery of a specific area that will become the periphery of the liquid crystal optical element can be cited. By indicating the periphery of the specific area with the alignment mark, it is easy to detect the position of the cutting line when the liquid crystal optical element is cut from the sheet, so that a liquid crystal optical element with a smaller error from the designed shape can be manufactured.

[0104] The alignment mark may be a mark indicating the optical center of the liquid crystal orientation pattern region. When cutting a liquid crystal optical element from a sheet, the alignment mark indicates the position of the optical center of the liquid crystal orientation pattern region, and the position of the cutting line can be set according to the indicated position, thereby manufacturing a liquid crystal optical element with a smaller error from the designed shape.

[0105] The alignment mark may be in any shape such as a cross, a dot, a straight line, a circle, a quadrilateral, etc. The alignment mark may be in the form of a cluster or a grid.

[0106] The number of alignment marks used to indicate the position of the object is not particularly limited, and only one alignment mark may be used depending on the object, or a plurality of alignment marks may be used in combination. Furthermore, the positions of a plurality of objects can be indicated by using a plurality of alignment marks in a different combination.

[0107] The alignment mark may be, for example, a region in which the optical axis derived from the liquid crystal compound included in the liquid crystal layer is oriented in a predetermined direction as a whole. Such an alignment mark can be formed by irradiating polarized light to a position corresponding to the alignment mark when the photo-alignment material included in the alignment film for forming the liquid crystal layer is oriented by polarized light irradiation.

[0108] 〔Specific Area〕

[0109] like Figure 1 As shown, the specific region 18 includes the liquid crystal orientation pattern region 12 and is configured to be cut out as a liquid crystal optical element. In other words, the element obtained by cutting out along the periphery of the specific region 18 can be used as a liquid crystal optical element through the liquid crystal orientation pattern region 12 functioning as an optical anisotropic layer.

[0110] exist Figure 1 In the sheet 1 shown, a plurality of liquid crystal alignment pattern regions 12 are separately arranged, and each of the liquid crystal alignment pattern regions 12 is included in the specific region 18. Therefore, a plurality of liquid crystal optical elements can be manufactured from the sheet 1 by cutting along the periphery of the specific region 18.

[0111] Furthermore, in the sheet of the present invention, the periphery of a specific area including a liquid crystal orientation pattern area that can be cut into a liquid crystal optical element can be included in any one of a peripheral area and a non-oriented area. The peripheral area is an area where the orientation degree of the liquid crystal compound is low, and the non-oriented area is an area where the liquid crystal compound is not oriented, so by cutting along the above-mentioned periphery, it is possible to suppress the occurrence of cracks in an undesirable direction in the end of the cut liquid crystal optical element. As a result, a plurality of liquid crystal optical elements with improved quality and uniformity of quality can be manufactured from the same sheet by a batch process. On the other hand, in the case of cutting a continuous area formed by an optical anisotropic layer formed by a liquid crystal orientation pattern in order to manufacture a plurality of liquid crystal optical elements from the same sheet, since the liquid crystal compound is regularly oriented along a constant direction in the optical anisotropic layer, cracks or defects in a direction different from the cutting direction are sometimes generated according to the cutting direction and the orientation direction of the liquid crystal compound, thereby reducing the quality of the liquid crystal optical element.

[0112] Figure 1 The specific region 18 shown is composed of the liquid crystal alignment pattern region 12 and a portion of the peripheral region 14 surrounding the liquid crystal alignment pattern region 12 .

[0113] The specific region of the sheet of the present invention is not limited to Figure 1The specific region may be composed of only the liquid crystal orientation pattern region, may further include at least a portion of the peripheral region, or may further include a portion of the non-oriented region. When the specific region includes a portion of the non-oriented region, it includes at least a portion of the peripheral region.

[0114] Figure 4 Another example of the structure of the sheet of the present invention is conceptually shown in FIG. Figure 4 This is a plan view of the sheet 110 of the present invention as viewed from the normal direction of the surface (main surface).

[0115] The sheet 110 has a liquid crystal layer (not shown) containing a liquid crystal compound, and the liquid crystal layer has a plurality of liquid crystal alignment pattern regions 200, wherein the liquid crystal alignment pattern regions 200 have a liquid crystal alignment pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane. The liquid crystal alignment pattern regions 200 function as an optically anisotropic layer in a liquid crystal optical element cut from the sheet 110.

[0116] In the sheet 110, a plurality of liquid crystal alignment pattern regions 200 are arranged separately from each other along the X direction and the Y direction that are orthogonal to each other in the plane. Figure 4 In the sheet 110 shown, the number of liquid crystal orientation pattern regions 200 arranged along the X direction is 4, and the number of liquid crystal orientation pattern regions 200 arranged along the Y direction is (n+1). As described above, the number of liquid crystal orientation pattern regions possessed by the sheet of the present invention is 2 or more in each of the two orthogonal directions, and the total number is 4 or more.

[0117] The periphery of the liquid crystal alignment pattern region 200 is surrounded by a peripheral region 201 having no liquid crystal alignment pattern and having a slow axis. The plurality of peripheral regions 201 respectively surrounding the plurality of liquid crystal alignment pattern regions 200 are arranged separately from each other along the X direction and the Y direction. That is, the outer periphery 500 of the peripheral region 201 is separated from the outer periphery 500 of other peripheral regions 201.

[0118] The non-oriented region 300 is disposed between the plurality of peripheral regions 201 in the sheet 110 , and is a region having neither a liquid crystal orientation pattern nor a slow axis.

[0119] Furthermore, a specific region 400 including the liquid crystal orientation pattern region 200 is formed on the sheet 110. The four sides of the specific region 400 are formed by the edge 112 of the sheet 110 and any one of the cutting lines X1 to Xn and Y1 to Y3. Each specific region 400 can be used as a liquid crystal optical element by cutting the sheet 110 along the cutting lines X1 to Xn and Y1 to Y3.

[0120] Figure 4The sheet 110 of the present invention shown in the above configuration of multiple liquid crystal orientation pattern areas 200, multiple peripheral areas 201 and non-oriented areas 300 produces spaces passing through cutting lines X1~Xn and Y1~Y3 when the liquid crystal optical element is cut into individual blades. It can be used as a multi-sided sheet of liquid crystal optical elements that can stably manufacture liquid crystal optical elements of excellent quality without damaging the optical anisotropic layer.

[0121] The thickness of the liquid crystal layer of the sheet of the present invention is appropriately set depending on the application of the liquid crystal optical element and the material forming the liquid crystal layer, but is preferably 3 μm or less, more preferably 1.0 to 2.9 μm, and further preferably 1.5 to 2.8 μm.

[0122] By setting the thickness of the liquid crystal layer to 3 μm or less, the viewing angle characteristics of the liquid crystal optical element can be expanded.

[0123] 〔Support〕

[0124] The sheet may further include a support for supporting the liquid crystal layer.

[0125] As the support, any of various sheet-like materials (including films and plates) can be used as long as they can support the liquid crystal layer.

[0126] The support may be a single layer or multiple layers.

[0127] As a single-layer support, there can be mentioned supports made of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate, polyvinyl chloride, acrylic acid, and polyolefins, etc. As a multilayer support, there can be mentioned a multilayer body comprising any of the above-mentioned single-layer supports as a substrate and providing other layers on the surface of the substrate.

[0128] The transmittance of the support to light diffracted by the liquid crystal alignment pattern region is preferably 50% or more, more preferably 70% or more, and even more preferably 85% or more.

[0129] The thickness of the support is not particularly limited, and may be appropriately set to a thickness capable of holding the liquid crystal layer and, if necessary, the alignment film or adhesive layer, depending on the application of the liquid crystal optical element and the material forming the support.

[0130] The thickness of the support is preferably 1 to 1000 μm, more preferably 3 to 250 μm, and even more preferably 5 to 150 μm.

[0131] When the sheet of the present invention is manufactured by forming a liquid crystal layer on a support using a liquid crystal layer-forming composition, an alignment film may be provided between the support and the liquid crystal layer. Furthermore, when a separately manufactured liquid crystal layer is provided on a support by transfer or the like, an adhesive layer may be provided between the support and the liquid crystal layer.

[0132] [Method for producing sheet]

[0133] The manufacturing method of the sheet of the present invention is not particularly limited as long as it is a method for forming a liquid crystal layer having each region configured as described above. As a manufacturing method of the sheet, for example, the following method can be cited: after forming an orientation film having a predetermined orientation limiting force on a support, a composition for forming a liquid crystal layer containing a liquid crystal compound (hereinafter also referred to as a "liquid crystal composition") is stacked on the orientation film, and the orientation of the liquid crystal compound included in the stacked coating is fixed to manufacture.

[0134] From the viewpoint of improving the uniformity of the quality of the liquid crystal optical element, it is preferred that the alignment films corresponding to different regions of the liquid crystal layer are the same. That is, it is preferred that a liquid crystal layer having a plurality of liquid crystal alignment pattern regions, peripheral regions, and non-aligned regions is formed on a coating film (alignment film) obtained by coating the same alignment film-forming composition on a support.

[0135] More specifically, the sheet of the present invention can be manufactured by sequentially performing the following steps: an alignment film forming step, in which an alignment film forming composition is applied to a support to form the same coating film, and then an alignment restricting force is applied to the coating film to form an alignment film having an alignment pattern for forming each liquid crystal optical element; and a liquid crystal layer forming step, in which a liquid crystal composition is applied to the alignment film to form the same coating film, a liquid crystal alignment pattern is generated by the alignment restricting force of the alignment film and the alignment forming ability of the liquid crystal compound, and a liquid crystal layer is formed by fixing the liquid crystal alignment pattern. In the liquid crystal layer forming step, the application of the liquid crystal composition and the formation and fixing of the liquid crystal alignment pattern can be repeated multiple times to form a laminated body composed of multiple layers.

[0136] Hereinafter, the alignment film forming step and the liquid crystal layer forming step will be described in detail respectively.

[0137] <Orientation Film Formation Step>

[0138] The alignment film forming step is a step of forming an alignment film having a predetermined alignment pattern for forming a liquid crystal layer having a liquid crystal alignment pattern in a predetermined region within a plane on the alignment film.

[0139] As the alignment film, a so-called photo-alignment film formed by irradiating a coating film including a photo-alignment material applied on a support with polarized light or non-polarized light is preferably used.

[0140] As the support for forming the alignment film, the support exemplified as the support for supporting the above-mentioned liquid crystal layer can be used.

[0141] As the alignment film, various known materials can be used. As the photo-alignment material for forming the alignment film, for example, as preferred examples, there can be cited Japanese Patent Publication No. 2006-285197, Japanese Patent Publication No. 2007-076839, Japanese Patent Publication No. 2007-138138, Japanese Patent Publication No. 2007-094071, Japanese Patent Publication No. 2007-121721, Japanese Patent Publication No. 2007-140465, Japanese Patent Publication No. 2007-156 Azo compounds described in Japanese Patent Publication No. 439, 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, Japanese Patent Publication No. 2002-265541 and Japanese Patent Publication No. 2002-317013 The maleimide and / or alkenyl-substituted nadic imide compound having a photo-alignment unit described in the Japanese Patent Nos. 4205195 and 4205198, the photo-crosslinkable silane derivatives described in Japanese Patent Nos. 2003-520878, 2004-529220 and 4162850, the photo-crosslinkable polyimide, the photo-crosslinkable polyamide and the photo-crosslinkable The invention also includes the photodimerizable compounds described in Japanese Unexamined Patent Application Publication No. 9-118717, Japanese Unexamined Patent Application Publication No. 10-506420, Japanese Unexamined Patent Application Publication No. 2003-505561, International Publication No. 2010 / 150748, Japanese Unexamined Patent Application Publication No. 2013-177561 and Japanese Unexamined Patent Application Publication No. 2014-012823, in particular, cinnamate compounds, chalcone compounds and coumarin compounds.

[0142] Among them, it is preferable to use an azo compound, a photo-crosslinkable polyimide, a photo-crosslinkable polyamide, a photo-crosslinkable polyester, a cinnamate compound, or a chalcone compound.

[0143] The thickness of the alignment film formed in the alignment film forming step is not particularly limited, and may be appropriately set to a thickness that can obtain desired alignment performance depending on the material used to form the alignment film.

[0144] The thickness of the alignment film is, for example, 0.01 to 5 μm, or preferably 0.05 to 2 μm.

[0145] The method of imparting the alignment regulating force to the above-mentioned material is not particularly limited, and various known methods corresponding to the material for forming the alignment film can be used.

[0146] As a method of imparting an alignment regulating force, photo-alignment is preferred. That is, irradiation with polarized light can be performed from a perpendicular direction or an oblique direction relative to the photo-alignment film, and irradiation with unpolarized light can be performed from an oblique direction relative to the photo-alignment film.

[0147] As an example of the alignment film forming step, there is a method in which an alignment film is applied to the surface of a support and dried, and then the alignment film is exposed to a laser beam to form an alignment pattern.

[0148] Figure 5 The process for exposing the alignment film to form a liquid crystal layer is conceptually shown in FIG. Figure 1 An example of an exposure device for a concentric circular alignment pattern of a liquid crystal alignment pattern shown.

[0149] Figure 5 The exposure device 80 shown has: a light source 84 provided with a laser 82, a polarization beam splitter 86 for splitting the laser beam M from the laser 82 into S-polarized light MS and P-polarized light MP, a reflector 90A arranged in the optical path of the P-polarized light MP and a reflector 90B arranged in the optical path of the S-polarized light MS, a lens 92 arranged in the optical path of the S-polarized light MS, a polarization beam splitter 94, a λ / 4 plate 96 and a mask 98.

[0150] The P polarized light MP split by polarization beam splitter 86 is reflected by mirror 90A and enters polarization beam splitter 94. On the other hand, the S polarized light MS split by polarization beam splitter 86 is reflected by mirror 90B, collected by lens 92 and enters polarization beam splitter 94.

[0151] The P-polarized light MP and the S-polarized light MS are combined by the polarization beam splitter 94, and become right-handed circularly polarized light and left-handed circularly polarized light corresponding to the polarization directions through the λ / 4 plate 96. Furthermore, they pass through the opening portion (not shown) of the mask 98 and are incident on the area of ​​the orientation film 32 on the support body 30 corresponding to the opening portion of the mask 98 (hereinafter also referred to as the "orientation area").

[0152] Here, due to the interference of right-handed circularly polarized light and left-handed circularly polarized light, the polarization state of the light irradiated on the alignment film 32 changes periodically in the form of interference fringes. Since the crossing angle of left-handed circularly polarized light and right-handed circularly polarized light changes from the inside to the outside of the concentric circles, an exposure pattern in which the pitch changes from the inside to the outside can be obtained. By such interference exposure, a concentric circular alignment pattern in which the alignment state changes periodically can be obtained in the alignment region of the alignment film 32.

[0153] In the exposure device 80, the length Λ of one cycle of the liquid crystal orientation pattern in which the optical axis of the liquid crystal compound continuously rotates 180° can be controlled by changing the refractive power of lens 92 (F value of lens 92), the focal length of lens 92, and the distance between lens 92 and the orientation film 32.

[0154] Furthermore, by adjusting the refractive power of lens 92, the length Λ of one cycle of the liquid crystal orientation pattern can be changed in one direction in which the optical axis of the liquid crystal compound continuously rotates. Specifically, by the diffusion angle of the light diffused by lens 92 that interferes with the parallel light, the length Λ of one cycle of the liquid crystal orientation pattern can be changed in one direction in which the optical axis of the liquid crystal compound continuously rotates. More specifically, if the refractive power of lens 92 is weakened, it approaches parallel light, so that the length Λ of one cycle of the liquid crystal orientation pattern gradually shortens from the inside to the outside, and the F value increases. On the contrary, if the refractive power of lens 92 is strengthened, the length Λ of one cycle of the liquid crystal orientation pattern shortens sharply from the inside to the outside, and the F value decreases.

[0155] In the exposure device 80, the mask 98 has an opening that limits the irradiation range of the right-handed circularly polarized light and the left-handed circularly polarized light in the alignment film 32. The right-handed circularly polarized light and the left-handed circularly polarized light pass through the opening of the mask 98, thereby irradiating the alignment region of the alignment film 32 with the right-handed circularly polarized light and the left-handed circularly polarized light, and forming an alignment pattern capable of forming a liquid crystal alignment pattern in the stacked liquid crystal layer. On the other hand, the right-handed circularly polarized light and the left-handed circularly polarized light are shielded by the mask 98 in the region other than the alignment region of the alignment film 32, thereby not imparting an alignment limiting force capable of forming a liquid crystal alignment pattern.

[0156] The size and shape of the opening of the mask 98 are appropriately selected according to the size and shape of the alignment region forming the alignment pattern in the alignment film 32 , that is, the size and shape of the liquid crystal alignment pattern region formed on the liquid crystal layer.

[0157] exist Figure 5 In the exposure device 80 shown, the mask 98 is provided at a position separated from the alignment film 32. When the alignment film 32 is exposed using the exposure device 80, the alignment film 32 is exposed using light passing through the opening of the mask 98 separated from the alignment film 32, thereby being able to impart a low orientation restriction force to the photo-alignment material included in the area surrounding the periphery of the alignment region of the alignment film 32, thereby making it easy to form a peripheral area surrounding the periphery of the liquid crystal alignment pattern area on the stacked liquid crystal layer.

[0158] The distance between the mask 98 and the orientation film 32 can be appropriately selected based on the size and shape of the area used to form the peripheral area in the orientation film 32 (i.e., the size and shape of the peripheral area formed in the liquid crystal layer), the size of the orientation area, the size and shape of the opening of the mask 98, the size and shape of the orientation area formed in the orientation film 32, etc.

[0159] According to the above method, the alignment film used for manufacturing the sheet of the present invention can be formed by repeatedly forming an alignment pattern along two orthogonal directions in the plane of the alignment film formed on the support.

[0160] The exposure method in the alignment film forming step is not limited to the above method, and various exposure methods that can form alignment films in a plurality of liquid crystal alignment pattern regions and a plurality of peripheral regions on the stacked liquid crystal layer can be used.

[0161] In the alignment film forming step, the alignment film can be formed by exposing the alignment film to light using a direct writing method.

[0162] Figure 6 The process for exposing the alignment film to form a liquid crystal layer is conceptually shown in FIG. Figure 1 Another example of an exposure device for a concentric circular alignment pattern of a liquid crystal alignment pattern shown.

[0163] Figure 6 The exposure device 100 shown includes a light source 102, a λ / 2 plate 104 for changing the polarization direction of light emitted from the light source 102, a lens 106 arranged on the optical path, and an XY stage 108. The exposure device 100 focuses a linearly polarized light beam directly on the alignment film, scans the focus position, and draws an alignment pattern on the alignment film.

[0164] The light source 102 includes a laser and a linear polarizer, and emits linearly polarized light. The emitted linearly polarized light enters the λ / 2 plate 104. The λ / 2 plate 104 is rotatably mounted and can rotate around an axis perpendicular to the XY plane of the XY stage 108.

[0165] The λ / 2 plate 104 rotates around an axis perpendicular to the XY plane and converts the polarization direction of the incident linear polarized light into an arbitrary direction. The lens 106 focuses the linear polarized light that has passed through the λ / 2 plate 104 on the surface of the alignment film 32 disposed on the XY stage 108. The support 30 having the alignment film 32 is disposed on the XY stage 108, and the position where the light is focused on the surface of the alignment film 32 is changed by moving the alignment film 32 (support 30) in the X direction and / or the Y direction (direction perpendicular to the paper surface). That is, the XY stage 108 scans the light on the surface of the alignment film 32.

[0166] The rotation of the λ / 2 plate 104 and the movement of the XY stage 108 are controlled by, for example, a computer, and a desired alignment pattern is formed on the alignment film by making the position where light is focused on the surface of the alignment film 32 correspond to the polarization direction of the light.

[0167] The irradiation of the light beam from the light source 102, the rotation of the λ / 2 plate 104, and the XY stage 108 may be performed alternately or simultaneously. That is, for example, after the XY stage 108 is driven to move the alignment film 32 to a predetermined position and stop, and the λ / 2 plate 104 is rotated so that the polarization direction of the linear polarized light passing through the λ / 2 plate 104 becomes a predetermined direction, the light beam is irradiated from the light source 102 to expose a predetermined position on the surface of the alignment film 32, and then the irradiation of the light is stopped. Next, the XY stage 108 is driven again to move the alignment film 32 to the next predetermined position (exposure position) and stop, and the λ / 2 plate 104 is rotated so that the polarization direction of the linear polarized light passing through the λ / 2 plate 104 becomes a predetermined direction, and then the light beam is irradiated from the light source 102 to expose a predetermined position on the surface of the alignment film 32, and then the irradiation of the light is stopped. In this way, the movement of the XY stage 108 and the irradiation of the light beam from the light source 102 are repeated alternately, and the exposure of the alignment film 32 can be performed intermittently.

[0168] Alternatively, the alignment film 32 may be continuously exposed by irradiating a light beam from the light source 102 while driving the XY stage 108 to move the alignment film 32 in a predetermined direction and rotating the λ / 2 plate 104 .

[0169] Alternatively, for example, when exposing an orientation pattern of regions having orientation axes in different directions in a stripe shape, the region where the λ / 2 plate is fixed in a certain direction and the orientation axes are in the same direction is exposed by irradiating a light beam from the light source 102 and driving the XY stage 108 to move the orientation film 32 in a predetermined direction. Next, in order to expose a region where the orientation axis is different from the previous region, the λ / 2 plate is rotated and then the XY stage 108 is driven to move the orientation film 32 in a predetermined direction. By repeatedly performing such exposure, an orientation pattern of regions having orientation axes in different directions in a stripe shape can be exposed.

[0170] The intensity of the light to be irradiated, the exposure time, etc. may be appropriately set according to the material of the alignment film.

[0171] The exposure amount per unit area can be adjusted by the intensity of the irradiated light and the scanning speed. From the viewpoint of sufficient exposure to impart orientation to the alignment film 32, the exposure amount per unit area is preferably 100 mJ / m2 More preferably, 150 mJ / m 2 In addition, from the viewpoint of preventing the decrease of orientation due to excessive irradiation, 5 J / m 2 Below, more preferably 3 J / m 2 the following.

[0172] Furthermore, the spot diameter of the light beam focused on the alignment film may be a size that can provide a desired alignment pattern to the alignment film.

[0173] <Liquid Crystal Layer Formation Step>

[0174] The liquid crystal layer forming step is a step of forming a liquid crystal layer on the alignment film formed in the alignment film forming step. The liquid crystal layer can be formed by fixing the liquid crystal compound in a layered state to be aligned in a liquid crystal phase in a predetermined liquid crystal alignment state.

[0175] The structure formed by fixing the liquid crystal phase only needs to be a structure that maintains the orientation of the liquid crystal compound that becomes the liquid crystal phase. Typically, the following structure is preferred: on the basis of setting the polymerizable liquid crystal compound to a specified orientation state, polymerization and curing are carried out by ultraviolet irradiation, heating, etc. to form a layer without fluidity, and at the same time, the state is changed to a state in which the orientation morphology will not change due to external fields or external forces.

[0176] In addition, in a structure formed by fixing a liquid crystal phase, as long as the optical properties of the liquid crystal phase are maintained, the liquid crystal compound may not exhibit liquid crystallinity in the liquid crystal layer. For example, a polymerizable liquid crystal compound may lose its liquid crystallinity by increasing its molecular weight through a curing reaction.

[0177] Examples of materials for forming a liquid crystal layer formed by fixing a liquid crystal phase include a liquid crystal composition containing a liquid crystal compound.

[0178] As the liquid crystal compound included in the liquid crystal composition, a known liquid crystal compound can be used, and a polymerizable liquid crystal compound is preferred because of its excellent heat resistance, durability, and handling properties.

[0179] Furthermore, the liquid crystal composition for forming the liquid crystal layer may further contain a surfactant, a polymerization initiator, a crosslinking agent, a solvent, and the like.

[0180] When forming the liquid crystal layer, it is preferred to apply the liquid crystal composition on the alignment film, and after the liquid crystal compound is oriented to a liquid crystal phase of a predetermined liquid crystal alignment state, the liquid crystal compound is cured to form the liquid crystal layer. As a result, in the liquid crystal layer, a liquid crystal alignment pattern region, a peripheral region, and a non-aligned region are formed according to the alignment restriction force given to the alignment film in the alignment film formation step, thereby manufacturing the sheet of the present invention.

[0181] Regarding the coating of the liquid crystal composition, any known method that can uniformly coat a liquid on a support, such as printing methods such as inkjet and roll printing, and spin coating, bar coating, and spray coating, can be used. In the liquid crystal layer forming step, by uniformly coating the liquid crystal composition, a liquid crystal layer having a plurality of specific regions that are precursors of a plurality of liquid crystal optical elements can be provided, thereby having the advantages of excellent manufacturing efficiency and quality of the liquid crystal optical elements, and high uniformity and stability of the quality of the manufactured liquid crystal optical elements.

[0182] The applied liquid crystal composition is dried and / or heated as required, and then cured, thereby forming a liquid crystal layer. In the drying and / or heating process, the liquid crystal compound in the liquid crystal composition is oriented to a predetermined orientation state. When heating is performed, the heating temperature is preferably 200° C. or less, and more preferably 130° C. or less.

[0183] The aligned liquid crystal compound is further polymerized as required. The polymerization may be any of thermal polymerization and photopolymerization based on light irradiation, but photopolymerization is preferred. Ultraviolet rays are preferably used for light irradiation. The irradiation energy is preferably 20 mJ / cm 2 ~50J / cm 2 , more preferably 50 to 1500 mJ / cm 2 In order to promote the photopolymerization reaction, light irradiation may be performed under heating conditions or in a nitrogen atmosphere. The wavelength of the ultraviolet rays to be irradiated is preferably 250 to 430 nm.

[0184] The support used in the alignment film formation step can be peeled off as needed. When peeling off the support, it can be peeled off together with the alignment film, or it can be peeled off between the alignment film and the support to remove only the support.

[0185] [Method for manufacturing liquid crystal optical element]

[0186] The sheet of the present invention is a multi-faceted sheet of a liquid crystal optical element. By cutting the sheet of the present invention into a predetermined shape, a liquid crystal optical element including a liquid crystal alignment pattern can be produced.

[0187] The method for producing a liquid crystal optical element preferably includes a step of cutting out a specific region including a liquid crystal orientation pattern from the sheet of the present invention.

[0188] By producing a liquid crystal optical element using the sheet of the present invention, a liquid crystal optical element having excellent quality and high uniformity and stability of quality can be obtained.

[0189] by Figure 1 Taking the sheet 1 shown as an example, the method of manufacturing a liquid crystal optical element from the sheet of the present invention will be described in more detail.

[0190] The periphery of the specific region 18 including the liquid crystal orientation pattern region 12 of the sheet 1 is formed by any one of the cutting lines X1 to X4 and Y1 to Y4. These cutting lines X1 to X4 and Y1 to Y4 are all included in any one of the peripheral region 14 and the non-oriented region 16, and do not pass through the liquid crystal orientation pattern region 12. By cutting the sheet 1 along such cutting lines X1 to X4 and Y1 to Y4, the specific region 18 is cut out to manufacture a plurality of liquid crystal optical elements including the liquid crystal orientation pattern region.

[0191] As a method for cutting the sheet, a known method can be used, and for example, a cutting method using laser cutting, a scraper, a trimmer, or the like is applicable.

[0192] As described above, the method for producing a liquid crystal optical element of the present invention, which produces a plurality of liquid crystal optical elements by cutting specific regions from the sheet, can more efficiently produce liquid crystal optical elements having excellent quality and excellent uniformity and stability of quality.

[0193] In the above-mentioned manufacturing method, it is shown that Figure 1 The sheet 1 shown in the figure is cut along the cutting lines X1 to X4 and Y1 to Y4 to cut out the specific area 18 formed by the liquid crystal orientation pattern area 12 and the peripheral area 14 surrounding a part of the periphery of the liquid crystal orientation pattern area 12. However, the cutting lines for cutting out the specific area from the sheet of the present invention are not limited to Figure 1 Cut-off line shown.

[0194] For example, Figure 4 As shown, the sheet 110 is cut along the cutting lines X1 to Xn and Y1 to Y3 to cut out a specific area 400 formed by the liquid crystal orientation pattern area 200, the peripheral area 201 and the non-oriented area 300 surrounding a part of the peripheral area 201, thereby manufacturing a liquid crystal optical element.

[0195] Furthermore, the cutting line for cutting out a specific area may include a straight portion and a curved portion. When the cutting line is formed only by a straight portion, cracks or other ruptures may occur at the corners where a plurality of cutting lines intersect due to the cutting of the sheet. In contrast, when the cutting line includes a straight portion and a curved portion, the occurrence of the above-mentioned cracks or other ruptures can be suppressed.

[0196] When the cutting line includes a straight portion and a curved portion, the minimum curvature radius of the curved portion is preferably 0.2 mm or more, more preferably 0.4 mm or more. The upper limit is not particularly limited, and is, for example, 20 mm or less, preferably 10 mm or less.

[0197] Furthermore, the cutting line for cutting out the specific region may be included in any one of the peripheral region and the non-oriented region. By including the cutting line in any one of the peripheral region and the non-oriented region, as described above, it is possible to suppress the occurrence of cracks in an undesired direction at the end of the liquid crystal optical element cut out along the periphery of the peripheral region, and as a result, a plurality of liquid crystal optical elements with improved quality and quality uniformity can be manufactured from the same sheet.

[0198] The cutting line for cutting out the specific area may be included only in the peripheral area. That is, the cutting line may be an annular line included only in the peripheral area and surrounding the liquid crystal pattern area. It is also possible to manufacture a liquid crystal optical element by cutting along such an annular cutting line and extracting a specific area formed by the liquid crystal orientation pattern area and a peripheral area surrounding a part of the periphery of the liquid crystal orientation pattern area.

[0199] The liquid crystal optical element produced from the sheet of the present invention can be preferably used as an optical component such as an optical path changing component, a light collecting element, a diffraction element, and a light diffusing element in an optical device.

[0200] In particular, the liquid crystal optical element manufactured from the sheet of the present invention can be preferably used as an optical component of an image display device constituting a head-mounted display such as AR (Augmented Reality) glasses, VR glasses, and MR (Mixed Reality) glasses. By using the sheet of the present invention, a head-mounted display can be manufactured in which individual differences of the liquid crystal optical element are small and the expected optical function is exhibited.

[0201] Explanation of symbols

[0202] 1. 110-sheet, 10-liquid crystal layer, 12. 200-liquid crystal orientation pattern area, 14. 201-peripheral area, 16. 300-non-oriented area, 18. 400-specific area, 30-support, 32-oriented film, 40-liquid crystal compound, 42-bright line, 44-dark line, 80. 100-exposure device, 82-laser, 84. 102-light source, 86. 94-polarization beam splitter, 90A, 90B-reflector, 92, 106-lens, 96-λ / 4 plate, 98-mask, 104-λ / 2 plate, 108-XY stage, 500-peripheral edge, X1, X2, X3, X4, Xn, Y1, Y2, Y3, Y4-cutting line.

Claims

1. A sheet having a liquid crystal layer containing a liquid crystal compound, wherein: The liquid crystal layer has a plurality of liquid crystal alignment pattern regions, each of which has a liquid crystal alignment pattern in which the direction of the optical axis of the liquid crystal compound changes while continuously rotating along at least one direction in a plane. The plurality of liquid crystal alignment pattern regions are arranged separately from each other along two directions orthogonal to each other in the plane of the liquid crystal layer, with the non-aligned regions sandwiched therebetween. In the liquid crystal layer, two or more liquid crystal alignment pattern regions are arranged in each of the two directions. The non-oriented region is a region that does not have any of the liquid crystal orientation pattern and the slow axis, The periphery of the liquid crystal alignment pattern region is surrounded by a peripheral region, The peripheral region is a region that does not have the liquid crystal alignment pattern and has a slow axis, A specific area including the liquid crystal alignment pattern area can be cut out as a liquid crystal optical element.

2. The sheet material according to claim 1, wherein The periphery of the liquid crystal alignment pattern region includes a straight line portion and a curved line portion. The minimum curvature radius of the curved portion is greater than 0.2 mm.

3. The sheet material according to claim 2, wherein: At least one alignment mark indicating the periphery of the specific area or the optical center of the liquid crystal alignment pattern area is provided in the non-alignment area.

4. The sheet material according to any one of claims 1 to 3, wherein The specific region is composed of the liquid crystal alignment pattern region and a part of the peripheral region.

5. The sheet material according to any one of claims 1 to 3, wherein The sheet further includes a support that supports the liquid crystal layer. 6 . A method for producing a liquid crystal optical element, comprising the step of cutting out a specific region including the liquid crystal alignment pattern region from the sheet according to claim 1 .

7. The method for manufacturing a liquid crystal optical element according to claim 6, wherein: In the above step, the sheet is cut along a cutting line including a straight portion and a curved portion to cut out the specific area. The minimum curvature radius of the curved portion is greater than 0.2 mm.

8. The method for manufacturing a liquid crystal optical element according to claim 7, wherein: The cutting line is included in any one of the peripheral region and the non-oriented region.

9. The method for manufacturing a liquid crystal optical element according to claim 8, wherein: The cutoff line is included only in the outer peripheral area.

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