Optical element and inspection method of optical element

Abstract

To provide an optical element capable of being easily inspected and improving production yield.SOLUTION: A roll-shaped optical element has a first direction orthogonal to a long direction of the roll, and a second direction parallel to the long direction of the roll. The optical element includes a substrate, an alignment layer and a liquid crystal layer in this order. A face of the alignment layer closer to the liquid crystal layer side includes a compound region obtained by combining a first alignment region and a second alignment region arranged on a second direction side of the first alignment region. In the compound region, the second alignment region is arranged on an extended line in the second direction from any sites of the first alignment region. The plurality of compound regions are arranged in the second direction. The optical element has prescribed functions which are exhibited by a region corresponding to the first alignment region. A region corresponding to the second alignment region is a dummy region which does not exhibit the prescribed functions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an optical element and a method for inspecting the optical element.

Background Art

[0002] There is a technical field in which optical elements are used to change the polarization state of light or the traveling direction of light.

[0003] The above-described optical element is used, for example, in a dimming device. In recent years, in personal authentication and vehicle autonomous driving, the development of devices equipped with optical sensors has been progressing. Examples of devices equipped with optical sensors include face recognition devices, LiDAR (light detection and ranging), etc. In such devices equipped with optical sensors, optical elements may also be used.

[0004] As a configuration of an optical element, a configuration having a liquid crystal layer on a substrate is known (Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Optical elements such as Patent Documents 1 and 2 are often manufactured in a roll-to-roll manner to improve manufacturing efficiency. For an optical element manufactured in a roll-to-roll manner, a liquid crystal layer is formed on a substrate by means such as coating. In order to improve the yield, an inspection is carried out during and after the manufacture to determine whether the liquid crystal layer is normally formed or not for an optical element manufactured in a roll-to-roll manner. The above-mentioned inspection is usually carried out by measuring general optical properties such as total light transmittance and haze.

[0007] Among optical elements, there are those that exhibit special optical functions such as diffraction. An optical element that exhibits a special optical function such as diffraction may not be able to measure general optical properties such as total light transmittance and haze due to its special optical function. For this reason, it has sometimes been impossible for conventional optical elements to easily carry out an inspection of the entire roll.

[0008] If a roll-shaped optical element is partially cut out and the cut-out portion is measured with a device capable of measuring a special optical function, it is possible to carry out an inspection of the entire roll. However, since a device capable of measuring a special optical function is only possessed by customers or is expensive, there are cases where the manufacturer of the optical element cannot prepare the device. In addition, when a roll-shaped optical element is partially cut out for inspection, the yield decreases according to the cut-out area.

[0009] An object of the present disclosure is to provide an optical element and a method for inspecting an optical element that are easy to inspect and can improve the yield.

Means for Solving the Problems

[0010] The present disclosure provides the following [1] to [2]. [1] A roll-shaped optical element in which an optical element is wound, The optical element has a first direction that is a direction orthogonal to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll, The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, The surface of the alignment layer on the liquid crystal layer side has a composite region combining a first alignment region and a second alignment region disposed on the second direction side of the first alignment region. Within the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary location of the first alignment region. A plurality of the composite regions are arranged in the second direction. The optical element has a predetermined function. The predetermined function is exhibited by a region corresponding to the first alignment region. A roll-shaped optical element in which a region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function.

[0011] [2] The following is a method for inspecting a roll-shaped optical element; "A roll-shaped optical element obtained by winding an optical element, The optical element has a first direction that is a direction orthogonal to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll. The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order. The surface of the alignment layer on the liquid crystal layer side has a composite region combining a first alignment region and a second alignment region disposed on the second direction side of the first alignment region. Within the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary location of the first alignment region. A plurality of the composite regions are arranged in the second direction. The optical element has a predetermined function. The predetermined function is exhibited by a region corresponding to the first alignment region. "A roll-shaped optical element in which a region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function."; A first step of setting a pass criterion value for a predetermined optical characteristic of the second alignment region; A second step of cutting out at least a part of the second alignment region from the roll-shaped optical element and measuring the predetermined optical characteristic. A third step of determining whether or not the measured value in the second step satisfies the pass reference value set in the first step, and an inspection method for a roll-shaped optical element.

Effect of the Invention

[0012] The optical element of the present disclosure is easy to inspect and can improve the yield. The inspection method of the optical element of the present disclosure can easily inspect the optical element and can improve the yield of the optical element.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the optical element and the inspection method of the optical element of the present disclosure will be described. [Roll-shaped optical element] A roll-shaped optical element in which the optical element is wound up, The optical element has a first direction that is perpendicular to the length direction of the roll and a second direction that is parallel to the length direction of the roll. The optical element has a base material, an alignment layer, and a liquid crystal layer in this order. The surface of the alignment layer on the liquid crystal layer side has a composite region that combines a first alignment region and a second alignment region arranged on the second direction side of the first alignment region. In the composite region, the second alignment region is arranged on the extension line in the second direction from any point of the first alignment region. A plurality of the composite regions are arranged in the second direction. The optical element has a predetermined function. The predetermined function is exhibited by a region corresponding to the first alignment region. A roll-shaped optical element in which the region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function.

[0015] In this specification, the "length direction of the roll" is, in other words, the winding direction of the roll. In this specification, the "direction perpendicular to the length direction of the roll" is, in other words, the width direction of the roll.

[0016] Figs. 1 to 3 are each a plan view showing an embodiment of the arrangement pattern of the first alignment region and the second alignment region on the surface of the alignment layer of the optical element of the present disclosure on the liquid crystal layer side. In Figs. 1 to 3, the surface of the alignment layer of the optical element on the liquid crystal layer side has a composite region that combines a first alignment region R1 and a second alignment region R2 arranged on the second direction A2 side of the first alignment region. In Figs. 1 to 3, in the composite region, the second alignment region R2 is arranged on the extension line in the second direction A2 from any point of the first alignment region R1. In Fig. 1, reference numerals Rm1 to Rm6 indicate individual composite regions, and in Figs. 2 to 3, reference numerals Rm1 to Rm2 indicate individual composite regions. In Figs. 1 to 3, reference numeral W1-1 indicates the length of the first alignment region R1 in the first direction A1, and reference numeral W2-1 indicates the length of the second alignment region R2 in the first direction A1.

[0017] FIG. 4 is a cross-sectional view showing an embodiment of the optical element of the present disclosure. The left-right direction in FIG. 4 indicates a second direction A2 that is parallel to the length direction of the roll. The optical element 100 in FIG. 4 has a substrate 10, an alignment layer 20, and a liquid crystal layer 30 in this order. In FIG. 4, a first alignment region R1 has a plurality of first recesses 21 on the surface of the alignment layer 20 on the liquid crystal layer 30 side. In FIG. 4, a second alignment region R2 has a plurality of second recesses 22 on the surface of the alignment layer 20 on the liquid crystal layer 30 side. In FIG. 4, reference sign D1 indicates the depth of the first recess 21, and reference sign D2 indicates the depth of the second recess 22.

[0018] FIGS. 1 to 4 are schematic diagrams. That is, the scales of the respective elements constituting the optical element 100 are schematized for easy illustration and are different from the actual scales. The same applies to the figures other than FIGS. 1 to 4.

[0019] <Configurations 1 to 6> The optical element of the present disclosure needs to satisfy the following Configurations 1 to 6. Configuration 1: The surface of the alignment layer on the liquid crystal layer side has a composite region that combines a first alignment region and a second alignment region disposed on the second direction side of the first alignment region. Configuration 2: In the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary position of the first alignment region. Configuration 3: A plurality of the composite regions are arranged in the second direction. Configuration 4: The optical element has a predetermined function. Configuration 5: The predetermined function is exhibited by a region corresponding to the first alignment region. Configuration 6: The region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function.

[0020] As will be described in the following (1) to (5), the optical element of the present disclosure can simplify the inspection of the optical element and improve the yield of the optical element according to Configurations 1 to 6. (1) According to Configuration 1, the optical element of the present disclosure specifies that the surface of the alignment layer on the liquid crystal layer side has a first alignment region and a second alignment region. Therefore, the liquid crystal layer at the location corresponding to the first alignment region is aligned based on the first alignment region, and the liquid crystal layer at the location corresponding to the second alignment region is aligned based on the second alignment region. (2) According to Configuration 1, the optical element of the present disclosure specifies that the second alignment region is arranged on the second direction side of the first alignment region. Furthermore, according to Configuration 2, the optical element of the present disclosure specifies that the second alignment region is arranged on the extension line from any location of the first alignment region in the second direction. Therefore, in the optical element of the present disclosure, the second alignment region will necessarily exist on the second direction side of the first alignment region. (3) When continuously producing the optical element in a roll-to-roll manner, defects may occur in the alignment of the liquid crystal layer. Defects in the alignment of the liquid crystal layer often occur continuously at the same location in the width direction of the roll. Since the optical element of the present disclosure specifies that the second alignment region exists on the extension line of the first alignment region in the second direction according to Configurations 1 and 2, if the region corresponding to the second alignment region is inspected and no defect is found in the alignment of the liquid crystal layer, it can be considered that no defect exists in the alignment of the liquid crystal layer of the first alignment region either. Examples of the inspection performed on the region corresponding to the second alignment region include measurement of the total light transmittance and haze, and inspection for confirming the extinction position using the following polarizing plate. <Inspection for Confirming the Extinction Position Using a Polarizing Plate> Prepare a laminate for inspection by placing a sample between two polarizing plates. In the laminate, the two polarizing plates are arranged such that their absorption axes are orthogonal to each other. While non-polarized light is incident from one side of the laminate, rotate the sample 360 degrees. Observe whether there is an angle at which the laminate is visually recognized as completely black while the sample is rotated 360 degrees. If the direction of the slow axis of the liquid crystal layer in the region corresponding to the second alignment region is constant, the angle at which the laminate is visually recognized as completely black will be observed 4 times while the sample is rotated 360 degrees. (4) According to Configuration 3, the optical element of the present disclosure specifies that a plurality of composite regions combining the first alignment region and the second alignment region are arranged in the second direction. Therefore, the inspection described in (3) above can be repeatedly performed in the length direction of the roll. (5) According to Configurations 4 to 6, the optical element of the present disclosure specifies that it has a region that exhibits a predetermined function and a region that does not exhibit a predetermined function. The predetermined function is a function exhibited by a region corresponding to the first alignment region. The region that does not exhibit the predetermined function is a region corresponding to the second alignment region. The region corresponding to the second alignment region is called a "dummy region" because it does not exhibit the predetermined function. Thus, the optical element of the present disclosure specifies that it deliberately forms the second region, which is a dummy region. Some optical elements exhibit special optical functions such as diffraction. Optical elements that exhibit special optical functions such as diffraction may not be able to measure general optical properties such as total light transmittance and haze due to their special optical functions. Therefore, conventional optical elements may not be able to easily perform inspections on the entire roll. The optical element of the present disclosure specifies that the dummy region does not exhibit a predetermined function. Therefore, regardless of the function exhibited by the region corresponding to the first alignment region, the optical element of the present disclosure can perform the inspection described in (4) above by inspecting the dummy region. And since the dummy region is a portion where a predetermined function is not exhibited, it is a portion that can be excluded from the optical element without problem. In other words, even if the dummy region is cut out from the optical element for inspection, the yield of the optical element does not decrease. From the above, the optical element of the present disclosure is easy to inspect and can improve the yield.

[0021] The predetermined function possessed by the optical element is, for example, a function exhibited by the direction of the slow axis of the liquid crystal layer in the region corresponding to the first alignment region changing stepwise along a single direction in the plane.

[0022] Functions exhibited by the stepwise change in the direction of the slow axis of the liquid crystal layer along one direction in the plane include the following functions (A1) to (A2). (A1) When circularly polarized light is incident as incident light, a function of diffracting the incident light and reversing the phase of the incident light. (A2) When natural light or linearly polarized light is incident as incident light, a function of diffracting the incident light and polarization-separating it into right-circularly polarized light and left-circularly polarized light.

[0023] When the functions (A1) and (A2) are exhibited, it is preferable to change the direction of the slow axis stepwise along one direction in the plane so that the directions of the slow axes of the liquid crystal layer are arranged in a circular or arc shape. FIG. 5 is a diagram showing a state in which the directions of the slow axes of the liquid crystal layer corresponding to the region of reference numeral R1' in FIG. 3 are arranged in an arc shape. In FIG. 5, the dotted line indicates the direction of the slow axis arranged in an arc shape. The circular solid line in FIG. 5 indicates the approximate outer edge of the region of reference numeral R1'. Also, when the functions (A1) and (A2) are exhibited, it is preferable that the in-plane retardation of the liquid crystal layer be within a range described later.

[0024] When the direction of the slow axis of the liquid crystal layer in the region corresponding to the first alignment region changes stepwise along one direction in the plane, it is preferable that the direction of the slow axis of the liquid crystal layer in the region corresponding to the second alignment region be constant. By adopting the above-described configuration, while a predetermined function is exhibited in the region corresponding to the first alignment region, the second alignment region can be easily made a dummy region that does not exhibit the predetermined function.

[0025] In this specification, the fact that the direction of the slow axis of the liquid crystal layer is constant means that the standard deviation σ of the angles of the slow axis measured at any 20 locations is 1.0 degree or less. The standard deviation σ is preferably 0.7 degree or less, and more preferably 0.5 degree or less. As a device capable of simultaneously measuring the directions of the slow axes at multiple locations in the liquid crystal layer, the product named "WPA" series by Photonic Lattice can be mentioned. The slow axis of the liquid crystal layer corresponding to the first alignment region is preferably measured with "WPA-Micro", and the slow axis of the liquid crystal layer corresponding to the second alignment region is preferably measured with "WPA-200-L".

[0026] The direction of the slow axis of the liquid crystal layer in the region corresponding to the second alignment region is preferably parallel or perpendicular to the first direction. Parallel includes substantial parallelism. Substantially parallel means that the angle formed by the direction of the slow axis and the first direction is 3.0 degrees or less, preferably 1.5 degrees or less, and more preferably 1.0 degree or less. Perpendicular includes substantial perpendicularity. Substantially perpendicular means that the range of the angle formed by the direction of the slow axis and the first direction is 90.0 degrees ± 3.0 degrees, preferably 90.0 degrees ± 1.5 degrees, and more preferably 90.0 degrees ± 1.0 degrees.

[0027] In this specification, the slow axis of the liquid crystal layer means the direction in which the in-plane refractive index of the liquid crystal layer is the highest.

[0028] <Substrate> As the material constituting the substrate, various materials can be used, but materials with good mechanical properties, optical properties, stability, and processability are preferred. Also, as the material constituting the substrate, materials with good suitability for roll-to-roll manufacturing are preferred. Such materials include polymer resins having an alicyclic structure, methacrylic resins, polycarbonate resins, polystyrene resins, acrylonitrile-styrene copolymers, methyl methacrylate-styrene copolymers, ABS resins, polyethersulfone, triacetyl cellulose, polyethylene terephthalate, epoxy acrylate, urethane acrylate, and other resins are preferred. That is, the substrate is preferably a resin substrate. Also, a thin film glass substrate can be used as the substrate.

[0029] The thickness of the substrate is not particularly limited, but is usually 5 μm or more and 1000 μm or less. The thickness of the substrate can be measured with a film thickness measuring instrument. Examples of the film thickness measuring instrument include Mitutoyo's Digital Indicator (product number: ID-F125). The thickness of the substrate may be the average value obtained by measuring any 10 points as long as it is the above numerical value.

[0030] The substrate preferably has a total light transmittance of 70% or more, more preferably 80% or more, and even more preferably 85% or more in accordance with JIS K7361-1:1997. The substrate preferably has a haze of 10% or less, more preferably 5% or less, and even more preferably 3% or less in accordance with JIS K7136:2000.

[0031] <Alignment layer> The optical element of the present disclosure has an alignment layer between the substrate and the liquid crystal layer. By having the alignment layer, the liquid crystal molecules in the liquid crystal layer are more likely to be aligned in a predetermined direction.

[0032] The surface of the alignment layer on the liquid crystal layer side has a composite region combining a first alignment region and a second alignment region arranged on the second direction side of the first alignment region (Configuration 1). According to Configuration 1, the liquid crystal layer at the location corresponding to the first alignment region is aligned based on the first alignment region, and the liquid crystal layer at the location corresponding to the second alignment region is aligned based on the second alignment region.

[0033] In one composite region Rm, the number of the first alignment regions R1 may be one as shown in FIG. 1, or may be two or more as shown in FIGS. 2 and 3. In one composite region Rm, the number of the second alignment regions R2 may be one as shown in FIGS. 1 to 3, or may be two or more (not shown).

[0034] The distance between any first alignment region and the second alignment region located at the position closest to the second direction from the any first alignment region is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 9 mm or less, and even more preferably 3 mm or more and 8 mm or less. By setting the interval to 1 mm or more, the first alignment region and the second alignment region can be easily distinguished visually, so that the region corresponding to the second alignment region can be easily inspected. By setting the interval to 10 mm or less, defects occurring in the region corresponding to the first alignment region can be more easily detected by inspecting the region corresponding to the second alignment region. Further, by setting the interval to 10 mm or less, the yield of the optical element can be easily improved. When the first alignment region of reference numeral R1' in FIG. 3 is used as a reference, the length of reference numeral d in FIG. 3 corresponds to the interval.

[0035] In the composite region of the alignment layer, the second alignment region is disposed on an extension line in the second direction from an arbitrary point of the first alignment region (Configuration 2). Therefore, in the optical element of the present disclosure, the second alignment region always exists on the second direction side of the first alignment region.

[0036] When the length of the first alignment region in the first direction is defined as W1-1 and the length of the second alignment region in the first direction is defined as W2-1, it is preferable that W1-1 < W2-1. By satisfying the relationship of W1-1 < W2-1, the second alignment region can be easily disposed on an extension line in the second direction from an arbitrary point of the first alignment region. Of course, in the optical element of the present disclosure, W1-1 = W2-1 may be satisfied.

[0037] The range of W1-1 varies depending on the intended optical characteristics and thus cannot be generally stated, but it is preferably 1.8 μm or more and 133,000 μm or less, more preferably 3.0 μm or more and 127,000 μm or less, and even more preferably 5.0 μm or more and 121,000 μm or less.

[0038] In this specification, numerical values calculated from the planar shape of the alignment layer such as W1-1, W2-1, the length of the first concave portion, and the length of the second concave portion are calculated from a photograph taken with a scanning electron microscope of the surface of the alignment layer on the liquid crystal layer side. The scanning electron microscope preferably performs imaging under the following conditions. Examples of the scanning electron microscope include the product name "SU8000" of Hitachi High-Technologies Corporation. <Imaging conditions> ·Acceleration voltage: 5.0 kV ·Emission current: 5.0 μA ·Probe current: High ·Detector: SE(U) ·WD: 8 mm ·Condenser lens 1: 5.0 ·Condenser lens 2: 1.0 ·Tilt function of the specimen stage: Input tilt angle "0.0"

[0039] When defining the length in the second direction of the second alignment region as W2-2, it is preferable that W2-2 is 6 mm or more and 50 mm or less, more preferably 15 mm or more and 40 mm or less, and even more preferably 21 mm or more and 30 mm or less. By setting W2-2 to 6 mm or more, it becomes easier to inspect the region corresponding to the second alignment region. By setting W2-2 to 50 mm or less, it becomes easier to improve the yield of the optical element. W2-2 in FIG. 1 corresponds to the length in the second direction of the second alignment region. Yes.

[0040] A plurality of the composite regions are arranged in the second direction (Configuration 3). Therefore, the optical element of the present disclosure can repeatedly perform inspection of the region corresponding to the second alignment region in the length direction of the roll. For the optical element of the present disclosure, the ratio of the length of the composite region to the total length in the second direction is preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more.

[0041] When defining the area of the first alignment region as S1 and the area of the second alignment region as S2, it is preferable that S1 / S2 is 0.2 or more and 40 or less, more preferably 0.5 or more and 10 or less, and even more preferably 1.0 or more and 4.0 or less.

[0042] The alignment layer may have recesses on the surface of the alignment layer on the liquid crystal layer side. By having recesses on the surface of the alignment layer on the liquid crystal layer side, it is possible to easily align the direction of the slow axis of the liquid crystal layer along the extending direction of the recesses.

[0043] When the alignment layer has recesses, it is preferable to satisfy the following Configuration 7. <Configuration 7> The first alignment region is a region having a plurality of first recesses on the surface of the alignment layer on the liquid crystal layer side, and the second alignment region is a region having a plurality of second recesses on the surface of the alignment layer on the liquid crystal layer side.

[0044] In Configuration 7, the number of the first recesses arranged in the first alignment region is preferably adjusted as appropriate in consideration of the target optical characteristics, the size of the first alignment region, the size of each first recess, and the like. In Configuration 7, the number of the second recesses arranged in the second alignment region is preferably adjusted as appropriate in consideration of the target optical characteristics, the size of the second alignment region, the size of each second recess, and the like.

[0045] When the alignment layer has recesses, it is preferable to satisfy Configuration 7 and the following Configuration 8. By satisfying Configuration 8, it is possible to easily improve the coating suitability of the coating liquid for forming the liquid crystal layer with respect to the second recesses, so that it is possible to easily perform the inspection based on the region corresponding to the second alignment region appropriately. Further, by satisfying Configuration 8, it is possible to easily align the direction of the slow axis of the liquid crystal layer in the second direction. That is, by satisfying Configuration 8, it is possible to easily make the direction of the slow axis of the liquid crystal layer in the region corresponding to the second alignment region constant. When satisfying Configuration 8, it is more preferable to further satisfy the following Configuration 9. <Configuration 8> The extending direction of the second recess is parallel to the second direction.

[0046] In this specification, the parallelism of the above-described configuration 8 includes being substantially parallel. Substantially parallel means that the angle formed between the extending direction of the second recess and the second direction is 3.0 degrees or less, preferably 1.5 degrees or less, and more preferably 1.0 degrees or less. The extending direction of the second recess means the major axis direction of the second recess.

[0047] When the alignment layer has a recess, it is preferable to satisfy the above-described configuration 7 and also satisfy the following configuration 9. By satisfying configuration 9, it is easier to make the coating suitability of the coating liquid for forming the liquid crystal layer for the first recess and the second recess equivalent, so that it is easier to properly perform the inspection based on the region corresponding to the second alignment region. Further, by satisfying configuration 9, it is easier to reduce the difference in film characteristics such as the adhesion between the liquid crystal layer corresponding to the first alignment region and the liquid crystal layer corresponding to the second alignment region. When satisfying configuration 9, it is more preferable to further satisfy the above-described configuration 8. <Configuration 9> When the depth of the first recess is defined as D1 and the depth of the second recess is defined as D2, D1 / D2 is 0.7 or more and 1.3 or less.

[0048] In configuration 9, D1 / D2 is preferably 0.8 or more and 1.2 or less, and more preferably 0.9 or more and 1.1 or less.

[0049] In the constituent requirements shown in this specification, when a plurality of options for the upper limit and a plurality of options for the lower limit of a numerical value are respectively shown, an embodiment within the range combined by selecting one from the options for the upper limit and one from the options for the lower limit is considered to be described. For example, as embodiments of the above range of D1 / D2, there are 0.7 or more and 1.3 or less, 0.7 or more and 1.2 or less, 0.7 or more and 1.1 or less, 0.8 or more and 1.3 or less, 0.8 or more and 1.2 or less, 0.8 or more and 1.1 or less, 0.9 or more and 1.3 or less, 0.9 or more and 1.2 or less, 0.9 or more and 1.1 or less.

[0050] The ranges of D1 and D2 are not particularly limited because they vary depending on the target optical element, but are preferably 2 nm or more and 200 nm or less, more preferably 10 nm or more and 100 nm or less, and even more preferably 15 nm or more and 50 nm or less. In this specification, D1 and D2 mean the average value of the maximum depths of arbitrarily extracted 10 recesses. By setting the depth of the recess to 2 nm or more, it becomes easier to orient the liquid crystal molecules along the recess. By setting the depth of the recess to 200 nm or less, it becomes easier to peel the alignment layer from the mold for shaping, so that the alignment layer can be formed more stably.

[0051] The depth of the recess shall be calculated from a photograph obtained by imaging a vertical cross-section of the optical element with a scanning electron microscope. The imaging conditions of the scanning electron microscope are preferably those described below. Examples of the scanning electron microscope include the product name "SU8000" of Hitachi High-Technologies Corporation. <Imaging Conditions> ·Acceleration voltage: 5.0 kV ·Emission current: 5.0 μA ·Probe current: High ·Detector: SE(U) ·WD: 8 mm ·Condenser lens 1: 5.0 ·Condenser lens 2: 1.0 ·Tilt function of the specimen stage: Enter tilt angle "0.0"

[0052] In the first alignment region, the first recesses may be formed continuously in the first direction A1 or may be formed separately in the first direction A1. In FIG. 6, in the first alignment region R1, the first recesses 21 are formed continuously in the first direction A1. In FIG. 7, in the first alignment region R1, the first recesses 21 are divided into five in the first direction A1. In the case where the first concave portions are continuously formed in the first direction within the first alignment region, it is preferable that the planar shape of one first concave portion is circular or arc-shaped. With such a configuration, it is possible to easily arrange the directions of the slow axes of the liquid crystal layer in the region corresponding to the first alignment region in a circular or arc shape. In the case where the first concave portions are formed separately in the first direction within the first alignment region, it is preferable to arrange the first concave portions so that the planar shape of the state in which the first concave portions are aggregated is circular or arc-shaped. With such a configuration, it is possible to easily arrange the directions of the slow axes of the liquid crystal layer in the region corresponding to the first alignment region in a circular or arc shape. Arranging the directions of the slow axes of the liquid crystal layer in the region corresponding to the first alignment region in a circular or arc shape means that the directions of the slow axes of the liquid crystal layer in the region corresponding to the first alignment region change stepwise along one direction in the plane.

[0053] Within the second alignment region, the second concave portions may be continuously formed in the first direction A1 or may be formed separately. In FIG. 6, within the second alignment region R2, the second concave portions 22 are continuously formed in the first direction A1. In FIG. 7, within the second alignment region R2, the second concave portions 22 are divided into seven in the first direction A1.

[0054] The length in the major axis direction of the first concave portions can be appropriately adjusted in consideration of the target optical characteristics, the length of the first alignment region in the first direction, the number of divisions of the first concave portions in the first direction, and the like. The length in the major axis direction of the second concave portions can be appropriately adjusted in consideration of the target optical characteristics, the length of the second alignment region in the first direction, the number of divisions of the second concave portions in the first direction, and the like.

[0055] The length in the minor axis direction of the first concave portions can be appropriately adjusted in consideration of the target optical characteristics, the length of the first alignment region in the second direction, the interval between adjacent first concave portions in the second direction, and the like. The length of the second recess in the minor axis direction can be appropriately adjusted in consideration of the target optical characteristics, the length of the second region in the second direction of the second alignment region, the interval between adjacent second recesses in the second direction, and the like.

[0056] As shown in FIG. 4, the alignment layer may have a thickness below the first recess and the second recess. The average value of the thickness below the recess is preferably 0.2 μm or more and 20 μm or less, more preferably 0.5 μm or more and 15 μm or less, and still more preferably 1.0 μm or more and 7 μm or less.

[0057] The alignment layer may have a photo-alignment region on the surface of the alignment layer on the liquid crystal layer side. By having a photo-alignment region on the surface of the alignment layer on the liquid crystal layer side, it is possible to easily align the liquid crystal molecules of the liquid crystal layer along the photo-alignment region.

[0058] When the alignment layer has a photo-alignment region, it preferably satisfies the following Configuration 10. <Configuration 10> The first alignment region has a first photo-alignment region on the surface of the alignment layer on the liquid crystal layer side, and the second alignment region has a second photo-alignment region on the surface of the alignment layer on the liquid crystal layer side.

[0059] When the alignment layer has a photo-alignment region, it preferably satisfies Configuration 10 and the following Configuration 11. By satisfying Configuration 11, it is possible to gradually change the direction of the slow axis of the liquid crystal layer in the region corresponding to the first alignment region along a single direction in the plane, and to easily make the direction of the slow axis of the liquid crystal layer in the region corresponding to the second alignment region constant. When the alignment layer has a photo-alignment region, it is preferable that the material for forming the alignment layer includes a photo-dimerizable resin. <Configuration 11> In the first alignment region, the alignment direction of the alignment layer changes stepwise along a single direction in the plane, and in the second photo-alignment region, the alignment direction of the alignment layer is constant.

[0060] In Configuration 11, when the alignment direction of the alignment layer in the first alignment region is gradually changed along one direction in the plane, the planar shape of the alignment direction of the alignment layer is preferably circular or arc-shaped. By adopting such a configuration, it is possible to easily arrange the directions of the slow axes of the liquid crystal layers in the regions corresponding to the first alignment region in a circular or arc shape. The circular or arc-shaped alignment pattern may be formed continuously in the first direction or may be formed by being divided in the first direction.

[0061] In Configuration 11, the alignment direction of the first alignment region can be gradually changed along one direction in the plane by, for example, the method of (1) or (2) below. (1) A method of exposing the alignment layer using a polarization mask patterned in a circular or arc shape. Examples of the polarization mask include a wire grid type polarization mask. When exposing, it is preferable to bring the alignment layer into close contact with the polarization mask. The ultraviolet rays used for exposure are preferably parallel light. (2) A method of exposing the alignment layer with polarized laser light. By changing the polarization direction of the laser for each location of the alignment film, an alignment pattern in which the planar shape of the alignment direction is circular or arc-shaped can be formed.

[0062] In Configuration 11, as a method of making the alignment direction of the alignment layer in the second alignment region constant, there is a method of exposing the alignment layer through a general-purpose polarizing plate. The direction of the absorption axis of the polarizing plate is not particularly limited as long as it is a constant direction. In the method of (1) above, when exposing the alignment layer in the second alignment region, it is preferable to bring the alignment layer into close contact with the polarizing plate. The ultraviolet rays used for exposure are preferably parallel light.

[0063] 《Material of the alignment layer》 The alignment layer preferably contains a resin. The proportion of the resin in the alignment layer is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more based on the total solid content of the alignment layer.

[0064] ―Resin― Examples of the resin for the alignment layer include a thermoplastic resin and a cured product of a curable resin composition. Among these, a cured product of a curable resin composition is preferred in order to improve the strength. When forming a photo-alignment region in the alignment layer, the resin of the alignment layer is preferably a photo-dimerizable resin. The proportion of the cured product of the curable resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more based on the total solid content of the alignment layer.

[0065] Examples of the cured product of the curable resin composition include a cured product of a thermosetting resin composition and a cured product of an ionizing radiation curable resin composition. Among these, a cured product of an ionizing radiation curable resin composition is preferred.

[0066] The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl group, vinyl group, and allyl group, and epoxy group, oxetanyl group, etc. As the ionizing radiation curable resin, a compound having an ethylenically unsaturated bond group is preferred. Further, from the viewpoint of suppressing damage to the alignment layer during the process of manufacturing an optical element, as the ionizing radiation curable resin, a compound having two or more ethylenically unsaturated bond groups is more preferred. Among them, a polyfunctional (meth)acrylate-based compound having two or more ethylenically unsaturated bond groups is still more preferred. As the polyfunctional (meth)acrylate-based compound, either a monomer or an oligomer can be used. Ionizing radiation means electromagnetic waves or charged particle beams having energy quanta capable of polymerizing or crosslinking molecules. Usually, ultraviolet rays (UV) or electron beams (EB) are used, but other electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion beams can also be used.

[0067] Among polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, 1,6-hexanediol diacrylate, and the like. Examples of trifunctional or higher (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, isocyanuric acid-modified tri(meth)acrylate, and the like. The above (meth)acrylate monomers may be those in which a part of the molecular skeleton is modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cycloalkyl, aromatic, bisphenol, or the like can also be used.

[0068] Examples of polyfunctional (meth)acrylate oligomers include acrylate-based polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylate is obtained, for example, by the reaction of a polyhydric alcohol, an organic diisocyanate, and hydroxy (meth)acrylate. Preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting an aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like having a functionality of 3 or more with (meth)acrylic acid, (meth)acrylates obtained by reacting an aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like having a functionality of 2 or more with a polybasic acid and (meth)acrylic acid, and (meth)acrylates obtained by reacting an aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like having a functionality of 2 or more with phenols and (meth)acrylic acid. The above-described radiation-curable resin can be used alone or in combination of two or more.

[0069] When the radiation-curable resin is an ultraviolet-curable resin, the coating liquid for forming the resin layer preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyldimethylketal, benzoyl benzoate, α-acyl oxime ester, thioxanthones, and the like. In addition, the photopolymerization accelerator can reduce the polymerization inhibition by air during curing and increase the curing rate. Examples thereof include one or more selected from isoamyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, and the like.

[0070] Examples of the photo-dimerizable resin include resins having structures such as cinnamate, coumarin, benzylidene phthalimide, benzylidene acetophenone, diphenylacetylene, stilbazoles, uracil, quinolinone, maleimide, and cinnamylidene acetic acid derivatives.

[0071] The alignment layer may contain additives such as a refractive index adjuster, an antioxidant, an ultraviolet absorber, a light stabilizer, and an antistatic agent as long as the effects of the present disclosure are not inhibited.

[0072] 《Method for Forming Alignment Layer》 The alignment layer having recesses can be formed, for example, by shaping the alignment layer before shaping using a plate having a shape complementary to the surface shape of the surface of the alignment layer on the liquid crystal layer side. More specifically, the alignment layer having recesses can be formed, for example, by the following steps 1 and 2.

[0073] Step 1: A step of applying a coating liquid for forming an alignment layer containing a resin on a substrate to form a layer containing the resin. Step 2: A step of shaping a layer containing a resin using a plate having a shape complementary to the surface shape of the surface of the alignment layer on the liquid crystal layer side.

[0074] When the coating liquid for forming the alignment layer contains a solvent, it is preferable to dry the solvent in Step 1.

[0075] When a curable resin is used as the resin, it is preferable to use a coating liquid for forming an alignment layer containing a curable resin composition as the coating liquid for forming the alignment 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 liquid in Step 1 is in an uncured state. When using a coating liquid for forming an alignment layer containing a radiation-curable resin composition as the coating liquid for forming the alignment layer in Step 1, it is preferable to irradiate radiation simultaneously with the shaping in Step 2 to cure the radiation-curable resin composition contained in the shaped layer.

[0076] When there is another layer such as a primer layer between the substrate and the alignment layer, it is preferable to perform a step of forming another layer on the substrate before Step 1.

[0077] The plate used in Step 2 can be produced by general-purpose means such as laser lithography, electron beam lithography, and FIB (Focused Ion Beam). The concavo-convex shape formed on the surface of the plate can be designed with general-purpose simulation software. It is also preferable to produce a large number of replicated plates of the plate produced by the above-mentioned means, arrange the large number of replicated plates side by side, and use them as a multi-sided plate. Replication of the plate can be carried out by general-purpose means such as electroforming. Examples of the shape of the plate include a flat plate shape and a cylindrical shape. A cylindrical plate can be processed in a roll-to-roll manner and is preferable in terms of excellent productivity.

[0078] <Liquid crystal layer> In the optical element of the present disclosure, the liquid crystal layer is formed on the alignment layer. The liquid crystal layer can be formed, for example, by applying a coating liquid for forming a liquid crystal layer containing a liquid crystal compound on an alignment layer and then drying and curing it as necessary. Examples of the means for applying the coating liquid for forming a liquid crystal layer include general coating means such as bar coating, comma coating, die coating, and spin coating.

[0079] Examples of the liquid crystal compound include one or more selected from rod-shaped liquid crystal compounds such as nematic liquid crystal compounds and smectic liquid crystal compounds, cholesteric liquid crystal compounds, and discotic liquid crystal compounds (disc-shaped liquid crystal compounds). In addition to the liquid crystal compound, the liquid crystal layer may further contain a chiral agent. For example, a liquid crystal layer containing a nematic liquid crystal compound and a chiral agent has an arrangement in which the direction of the molecules of the liquid crystal compound is twisted in the thickness direction when viewed in plan view.

[0080] The liquid crystal compound is preferably a rod-shaped liquid crystal compound. The rod-shaped liquid crystal compound is not particularly limited, and examples include the compounds shown in the following (1) to (17).

[0081]

Chemical formula

[0082]

Chemical formula

[0083] Among the liquid crystal compounds, a polymerizable rod-shaped liquid crystal material is preferred. Examples of the polymerizable functional group of the polymerizable rod-shaped liquid crystal material include those that polymerize by the action of ionizing radiation such as ultraviolet rays and electron beams, or heat. Specific examples include radical polymerizable functional groups. Examples of the radical polymerizable functional group include a functional group having at least one addition-polymerizable ethylenically unsaturated double bond, and more specifically, a vinyl group, an acrylate group (a general term including an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group), with or without a substituent.

[0084] The liquid crystal layer is preferably formed over the entire surface of the alignment layer. The thickness of the liquid crystal layer may be adjusted according to the target value of the retardation.

[0085] The liquid crystal layer may have a single-layer structure or a multi-layer structure. For thinning, the liquid crystal layer preferably has a single-layer structure. For broadband, the liquid crystal layer preferably has a multi-layer structure.

[0086] The liquid crystal layer may have positive wavelength dispersibility or negative wavelength dispersion. Negative wavelength dispersibility is a characteristic in which the retardation imparted to the transmitted light increases as the wavelength of the transmitted light becomes longer. Positive wavelength dispersibility is a characteristic in which the retardation imparted to the transmitted light decreases as the wavelength of the transmitted light becomes longer. In this specification, when the in-plane retardation at a wavelength of 450 nm is defined as Re450 and the in-plane retardation at a wavelength of 550 nm is defined as Re550, the characteristic in which Re450 < Re550 is referred to as negative wavelength dispersibility. In this specification, the characteristic in which Re450 > Re550 is referred to as positive wavelength dispersibility.

[0087] In an optical element in which a liquid crystal layer is laminated on an alignment layer, the shape of the concave portion of the alignment layer can be confirmed by, for example, the following method (1) or (2). In addition, if it is a method by which the liquid crystal layer on the alignment layer can be easily removed, the shape of the concave portion of the alignment layer may be confirmed by a method other than the following methods (1) and (2). (1) According to JIS K5600-5-6:1999, make a 100-square grid cut at 1 mm intervals on the surface of the liquid crystal layer. Then, stick a 18 mm cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. on the cut portion, and rub the tape with an eraser on it to firmly attach the tape to the coating film. Then, repeat the operation of instantaneously peeling off the tape 10 times or more to peel off the coating film. If a part of the coating film of the grid cut peels off during the above-described operation, it is preferable to repeat the above-described operation centering on the peeled portion. In this way, the shape of the concave portion of the alignment layer can be confirmed by peeling off the liquid crystal layer on the alignment layer. (2) By using a cross-section cutting method used for cross-section observation such as STEM, the optical element is cross-section cut as thinly as possible, and the operation of taking a cross-section STEM image is repeated. By connecting the obtained cross-section STEMs and visualizing them in three dimensions, the shape of the concave portion of the alignment layer can be confirmed.

[0088] <Other layers> The optical element of the present disclosure may further have other layers. Examples of the other layers include a primer layer for improving the adhesion between the substrate and the alignment layer, an antistatic layer, and the like.

[0089] <Phase difference> The optical element may have an average value of the in-plane phase difference in a region corresponding to the first alignment region and a region corresponding to the second alignment region within a predetermined range.

[0090] When the wavelength to be controlled is λ [nm], the in-plane phase difference in the region corresponding to the first alignment region is preferably (λ / 2)×0.95 or more and (λ / 2)×1.05 or less, preferably (λ / 2)×0.97 or more and (λ / 2)×1.03 or less, and more preferably (λ / 2)×0.99 or more and (λ / 2)×1.01 or less. By setting the average value of the in-plane phase difference in the region corresponding to the first alignment region within the above range, for example, the functions of (A1) and (A2) above can be easily exhibited. The in-plane phase difference in the region corresponding to the first alignment region means the average value of five in-plane phase differences excluding the maximum value and the minimum value from the seven in-plane phase differences in the region corresponding to the first alignment region. In this specification, unless otherwise specified, the wavelength λ of the light serving as the reference for the phase difference is 543 nm. Examples of the in-plane phase difference measuring device include "Product name: WPA-Micro" or "Product name: WPA-200-L" of Photonic Lattice Co., Ltd. The former product is suitable for measuring the in-plane phase difference in the region corresponding to the first alignment region, and the latter product is suitable for measuring the in-plane phase difference in the region corresponding to the second alignment region. When the in-plane phase difference of the region corresponding to the second alignment region is set with the wavelength controlled in the first alignment region being λ [nm], it is preferably (λ / 2)×0.95 or more and (λ / 2)×1.05 or less, more preferably (λ / 2)×0.97 or more and (λ / 2)×1.03 or less, and still more preferably (λ / 2)×0.99 or more and (λ / 2)×1.01 or less.

[0091] The length and width of the roll-shaped optical element are not particularly limited. Usually, the roll-shaped optical element has a length of 100 mm or more and 4,000,000 mm or less, and a width of 100 mm or more and 2,400 mm or less.

[0092] <Use> The roll-shaped optical element of the present disclosure can be used, for example, as a diffractive optical element. When using the roll-shaped optical element of the present disclosure as a diffractive optical element or the like, it is preferable to cut out a portion corresponding to the first alignment region from the roll-shaped optical element and use it. The light transmitted through the diffractive optical element can be adjusted to be within a predetermined diffraction angle range. Therefore, for example, by using a diffractive optical element, the irradiation range of light can be widened or narrowed. Also, by causing the light transmitted through the diffractive optical element to interfere with each other, the actions of a lens, a prism, etc. can be produced. Due to the above-described actions, the diffractive optical element can be used, for example, as a member of devices such as cross-reality, optical sensors, and laser projectors.

[0093] The diffraction angle θ of the diffractive optical element can be expressed by the following formula when the pitch is x [nm], the wavelength of light is λ [nm], and the incident angle of light is θ0. θ and θ0 are the angles when the perpendicular direction to the in-plane of the diffractive optical element is 0 degrees. In the following formula, θ0 is the case in the plus direction from the perpendicular direction. The plus or minus sign is attached because there are cases of diffracting in the plus direction and the minus direction with respect to the perpendicular direction depending on the rotation direction of the circularly polarized light that is the incident light. The pitch (x) in the following formula means the pitch in the first direction of the first alignment region. P1 in FIGS. 2 and 6 corresponds to the pitch (x) in the following formula. sinθ = ±(λ / x) + sinθ0

[0094] For example, when the incident angle θ0 is fixed at 0 degrees and the wavelength of light is 1550 nm, the relationship between the pitch and the diffraction angle is as shown in Table 1 below. [Table 1]

[0095] The diffraction angle in Table 1 is the angle when there is one diffractive optical element. If the polarization state is the same, when the number of diffractive optical elements is increased, the diffraction angle increases by a multiple of the number of diffractive optical elements. When the diffraction angle at an arbitrary pitch is θ (degrees) and the number of diffractive optical elements is n, the diffraction angle can be expressed as 2 n-1 ×θ (degrees).

[0096] [Sheet-like optical element] The sheet-like optical element of the present disclosure is obtained by cutting out a sheet-like optical element from the roll-like optical element of the present disclosure described above so as to include at least one or more composite regions.

[0097] For the sheet-like optical element of the present disclosure, if the region corresponding to the second alignment region is inspected and there are no defects in the alignment of the liquid crystal layer, it can be considered that there are no defects in the alignment of the liquid crystal layer in the first alignment region either.

[0098] [Inspection method for roll-like optical element] The following is a method for inspecting a roll-shaped optical element; "A roll-shaped optical element obtained by winding an optical element, wherein the optical element has a first direction that is perpendicular to the length direction of the roll and a second direction that is parallel to the length direction of the roll, the optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, a surface of the alignment layer on the liquid crystal layer side has a composite region that combines a first alignment region and a second alignment region disposed on the second direction side of the first alignment region, in the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary point in the first alignment region, a plurality of the composite regions are arranged in the second direction, the optical element has a predetermined function, the predetermined function is exhibited by a region corresponding to the first alignment region, and a region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function, a roll-shaped optical element."; a first step of setting a pass criterion value for a predetermined optical property of the second alignment region; a second step of cutting out at least a part of the second alignment region from the roll-shaped optical element and measuring the predetermined optical property; and a third step of determining whether or not the measured value in the second step satisfies the pass criterion value set in the first step, a method for inspecting a roll-shaped optical element.

[0099] An embodiment of the roll-shaped optical element used in the method for inspecting a roll-shaped optical element of the present disclosure is as described in the embodiment of the roll-shaped optical element of the present disclosure.

[0100] <First step> The first step is a step of setting a pass criterion value for a predetermined optical property of the second alignment region.

[0101] In the first step, for example, any one of the following pass criterion values (1) to (3) is set. Set the acceptance criteria such that the total light transmittance of JIS K7361-1:1997 is x% or more and y% or less. Set the acceptance criteria such that the haze of JIS K7136:2000 is x% or more and y% or less. In the above-mentioned "inspection for confirming the extinction position using a polarizing plate", set the acceptance criteria such that the angle at which the laminate is visually recognized as completely black is observed 4 times while the sample is rotated 360 degrees.

[0102] <Second Step> The second step is a step of cutting out at least a part of the second alignment region from the roll-shaped optical element and measuring the predetermined optical characteristics.

[0103] The second alignment region has a predetermined length in the first direction and the second direction. The inspection in the second step is preferably carried out near the center of the second alignment region.

[0104] <Third Step> The third step is a step of determining whether the measured value in the second step satisfies the acceptance criterion value set in the first step.

[0105] This disclosure includes the following [1] to [9]. [1] A roll-shaped optical element obtained by winding an optical element, The optical element has a first direction that is a direction perpendicular to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll, The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, The surface of the alignment layer on the liquid crystal layer side has a composite region that combines a first alignment region and a second alignment region arranged on the second direction side of the first alignment region, In the composite region, the second alignment region is arranged on the extension line in the second direction from any point of the first alignment region, A plurality of the composite regions are arranged in the second direction, The optical element has a predetermined function, The predetermined function is expressed by a region corresponding to the first alignment region, A roll-shaped optical element, wherein a region corresponding to the second alignment region is a dummy region that does not express the predetermined function. [2] The roll-shaped optical element according to [1], wherein when the length of the first alignment region in the first direction is defined as W1-1 and the length of the second alignment region in the first direction is defined as W2-1, W1-1 < W2-1. [3] The first alignment region is a region having a plurality of first recesses on the surface of the alignment layer on the liquid crystal layer side, The second alignment region is a region having a plurality of second recesses on the surface of the alignment layer on the liquid crystal layer side, The roll-shaped optical element according to [1] or [2], wherein the extending direction of the second recess is parallel to the second direction. [4] The roll-shaped optical element according to [3], wherein when the depth of the first recess is defined as D1 and the depth of the second recess is defined as D2, D1 / D2 is 0.7 or more and 1.3 or less. [5] In the liquid crystal layer of the region corresponding to the first alignment region, the direction of the slow axis changes stepwise along one direction in the plane, and in the liquid crystal layer of the region corresponding to the second alignment region, the direction of the slow axis is constant. The roll-shaped optical element according to any one of [1] to [4]. [6] The roll-shaped optical element according to any one of [1] to [5], wherein the predetermined function is a function expressed by the stepwise change of the direction of the slow axis of the liquid crystal layer in the region corresponding to the first alignment region along one direction in the plane. [7] The roll-shaped optical element according to [6], wherein the predetermined function is the function of (A1) below. (A1) When circularly polarized light is incident on the optical element as incident light, the function of diffracting the incident light and inverting the phase of the incident light. [8] A sheet-shaped optical element obtained by cutting out a sheet-shaped optical element from the roll-shaped optical element according to any one of [1] to [7] so as to include at least one or more composite regions. [9] An inspection method for the roll-shaped optical element described below; A roll-shaped optical element in which an optical element is wound, The optical element has a first direction that is a direction orthogonal to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll, The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, A surface of the alignment layer on the liquid crystal layer side has a composite region that combines a first alignment region and a second alignment region disposed on the second direction side of the first alignment region, In the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary point in the first alignment region, A plurality of the composite regions are arranged in the second direction, The optical element has a predetermined function, The predetermined function is exhibited by a region corresponding to the first alignment region, A region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function, a roll-shaped optical element. "; A first step of setting a pass criterion value for a predetermined optical characteristic of the second alignment region; A second step of cutting out at least a part of the second alignment region from the roll-shaped optical element and measuring the predetermined optical characteristic; A third step of determining whether or not a measurement value in the second step satisfies the pass criterion value set in the first step, an inspection method for a roll-shaped optical element.

Example

[0106] Next, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited by these examples. Note that "parts" and "%" are based on mass unless otherwise specified.

[0107] 1. Production of a plate <Design of shape by simulation> Using a simulation tool, the shape of an alignment layer having a first recess in the first alignment region and a second recess in the second alignment region was designed. The first concave portion was shaped to have an arcuate shape in plan view as shown in FIG. 6. In FIG. 6, within the composite region Rm, the number of arrays of the first alignment regions R1 in the first direction and the number of arrays of the first alignment regions R1 in the second direction are both two, but the number of arrays was increased. Specifically, the number of arrays of the first alignment regions R1 was increased until the size surrounding the plurality of first alignment regions R1 reached 30 mm in the first direction and the second direction. The length of each first concave portion in the uniaxial direction was set to 25 nm. The pitch P1 of the first concave portions was gradually changed from 0.5 μm to 5000 μm in the first direction. The second concave portion was designed to have a shape continuous in the first direction as shown in FIG. 6. The extending direction of the second concave portion was made parallel to the first direction. Also, the length of each second concave portion in the second direction was set to 50 mm. The second alignment region was made such that W2-1 is 35 mm and W2-2 is 25 mm. The length of the symbol d in FIG. 6 was set to 5 mm. The depths of the first concave portion and the second concave portion were both set to 30 nm. <Fabrication of the plate using the above data> Using a 6-inch square synthetic quartz plate, an electron beam lithography process using an electron beam drawing apparatus and a dry etching apparatus was used to fabricate a quartz master mold having the surface shape designed by simulation. Next, after pouring an ultraviolet curable resin into the master mold, a transparent substrate was overlaid on the ultraviolet curable resin. Then, ultraviolet rays were irradiated to cure the resin. Then, the transparent substrate and the resin were peeled off from the master mold to obtain a resin plate having a shape complementary to the shape of the master mold. Next, an electroforming method was used to obtain a replica mold of the master mold, which is a mold having a shape complementary to the shape of the resin plate. A plurality of the replica molds were fabricated. A plurality of the replica molds were wound around a roll to fabricate a roll-shaped plate used in the examples.

[0108] 2. Fabrication of the optical element A primer layer with the following formulation was applied and dried on a substrate (cycloolefin polymer with a thickness of 40 μm, trade name "Zeonor" from Zeon Corporation, Japan) to form a primer layer with a thickness of 0.5 μm. Next, a coating solution for forming an alignment layer having the following formulation was applied onto the primer layer, dried, to form a layer containing an uncured resin. Next, using the roll-shaped plate produced in the above “2”, while shaping the layer containing the uncured resin, ultraviolet rays were irradiated from the substrate side (integrated light quantity: 500 mJ / cm 2 ), and the layer containing the shaped resin was cured. Next, the shaped layer was peeled off from the plate to obtain a laminate having a primer layer and an alignment layer on the substrate. Next, a coating solution for forming the following liquid crystal layer was applied onto the alignment layer, dried, and then irradiated with ultraviolet rays (integrated light quantity: 150 mJ / cm 2 ) to form a liquid crystal layer. The liquid crystal layer used a liquid crystal having an in-plane birefringence (Δn) of 0.141, and the film thickness was adjusted so that the in-plane retardation at a wavelength of 532 nm in the regions corresponding to the first and second alignment regions was 266 nm (the in-plane retardation at a wavelength of 543 nm was 264 nm). The liquid crystal layer with the above film thickness was formed by two coatings. Through the above steps, a roll-shaped optical element of the example was obtained. The optical element of the example was produced in a roll-to-roll manner. For the roll-shaped optical element of the example, if there are no defects, the directions of the slow axes of the liquid crystal layer in the regions corresponding to the first alignment region are arranged in an arc shape, and the directions of the slow axes of the liquid crystal layer in the regions corresponding to the second alignment region are arranged parallel to the first direction. For the roll-shaped optical element of the example, the wavelength controlled in the region corresponding to the first alignment region is 532 nm.

[0109] <Coating solution for forming primer layer> · Polyolefin resin: 70 parts by mass (Manufactured by Mitsubishi Chemical Corporation, trade name: Surflen P-1000) · Silica-based lubricant: 5 parts by mass (Manufactured by CIK Nanotech Co., Ltd., trade name: SIRMIBK15WT%-E65) · Methyl ethyl ketone: 25 parts by mass

[0110] <Coating solution for forming alignment layer> · Pentaerythritol triacrylate: 96 parts by mass (Manufactured by Nippon Kayaku Co., Ltd., trade name: PET-30) · Photoinitiator: 4 parts by mass (Manufactured by IGM, trade name: Omnirad184)

[0111] <Coating liquid for forming liquid crystal layer> · Rod-shaped liquid crystal molecules: 10 parts by mass (LC242 (trade name), manufactured by BASF, in-plane birefringence (Δn) = 0.141) · Photoinitiator: 0.4 parts by mass (Manufactured by IGM, trade name: Omnirad184) · Methyl ethyl ketone: 89.6 parts by mass

[0112] 3. Inspection of optical properties (1) Acquisition of test sample From the roll-shaped optical element of the example, a portion corresponding to the second alignment region was cut out in a size of 20 mm × 20 mm to obtain a test sample. Ten of the above samples were obtained from different portions of the roll-shaped optical element of the example. (2) Setting of acceptance criteria In the roll-shaped optical element of the example, if there are no defects, the directions of the slow axes of the liquid crystal layers in the region corresponding to the second alignment region are arranged parallel to the first direction. Therefore, if there are no defects, during the 360-degree rotation of the sample by the following inspection, the angles at which the laminate is visually recognized as completely black will be observed 4 times. Therefore, "During the 360-degree rotation of the sample by the following inspection, the angles at which the laminate is visually recognized as completely black are observed 4 times" was set as the acceptance criteria. (Inspection for confirming the extinction position using a polarizing plate) Prepare a test laminate in which the sample is placed between two polarizing plates. In the laminate, the two polarizing plates are arranged such that their absorption axes are orthogonal to each other. While non-polarized light is incident from one side of the laminate, the sample is rotated 360 degrees. Observe whether there is an angle at which the laminate is visually recognized as completely black while the sample is rotated 360 degrees. (3) Judgment as to whether the acceptance criteria are met Ten samples were judged whether they met the acceptance criteria set in (2).

[0113] 4. Verification of Inspection Validity (1) Acquisition of Samples for Validity Confirmation Ten confirmation samples were obtained by cutting out ten locations corresponding to the first alignment region from the roll-shaped optical element of the example. The size of the confirmation samples was 20 mm × 20 mm. Also, the locations where the confirmation samples were cut out were the same as those of the samples used in the above “3” in the first direction. Furthermore, the locations where the confirmation samples were cut out were on the core side of the samples used in the above “3” and close to the samples used in the above “3”. (2) Comparison of Laser Light Intensity The intensity of the laser light with a wavelength of 532 nm was measured using a laser detector. If there are no defects in the optical element, the laser light with a wavelength of 532 nm is diffracted in the region corresponding to the first alignment region. For this reason, if there are no defects in the optical element, the intensity of the laser light passing through the confirmation sample becomes 1% or less of the original intensity. On the other hand, if there are defects in the optical element, the intensity of the laser light passing through the confirmation sample does not decrease significantly from the original intensity, so it will greatly exceed 1%. The intensity of the laser light passing through ten confirmation samples was measured. As a result, the confirmation samples corresponding to the samples that met the acceptance criteria in the above “3” reduced the intensity of the original laser light to 1% or less. On the other hand, the confirmation samples corresponding to the samples that did not meet the acceptance criteria in the above “3” could not reduce the intensity of the original laser light to 1% or less. As described above, by inspecting the optical characteristics of the second region which is a dummy region, it is possible to confirm whether there are defects in the first region.

Explanation of Reference Signs

[0114] 10: Substrate 20: Alignment Layer 21: First Recess 22: Second Recess 30: Liquid Crystal Layer 100: Optical element R1: First alignment region R2: Second alignment region Rm, Rm1, Rm2, Rm3, Rm4, Rm5, Rm6: Composite region A1: First direction A2: Second direction

Claims

1. A roll-shaped optical element in which an optical element is wound, The optical element has a first direction that is a direction orthogonal to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll, The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, The surface of the alignment layer on the liquid crystal layer side has a composite region combining a first alignment region and a second alignment region disposed on the second direction side of the first alignment region, In the composite region, the second alignment region is disposed on an extension line in the second direction from an arbitrary point of the first alignment region, A plurality of the composite regions are arranged in the second direction, The optical element has a predetermined function, The predetermined function is exhibited by a region corresponding to the first alignment region, A roll-shaped optical element in which a region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function.

2. The roll-shaped optical element according to claim 1, wherein when the length of the first alignment region in the first direction is defined as W1-1 and the length of the second alignment region in the first direction is defined as W2-1, W1-1 < W2-1.

3. The first alignment region is a region having a plurality of first recesses on the surface of the alignment layer on the liquid crystal layer side, The second alignment region is a region having a plurality of second recesses on the surface of the alignment layer on the liquid crystal layer side, The roll-shaped optical element according to claim 1, wherein the extending direction of the second recess is parallel to the second direction.

4. The roll-shaped optical element according to claim 3, wherein when the depth of the first recess is defined as D1 and the depth of the second recess is defined as D2, D1 / D2 is 0.7 or more and 1.3 or less.

5. In the liquid crystal layer of the region corresponding to the first alignment region, the direction of the slow axis changes stepwise along one direction in the plane, and in the liquid crystal layer of the region corresponding to the second alignment region, the direction of the slow axis is constant. The roll-shaped optical element according to claim 1.

6. The roll-shaped optical element according to claim 1, wherein the predetermined function is a function exhibited by the direction of the slow axis of the liquid crystal layer in the region corresponding to the first alignment region changing stepwise along one direction in the plane.

7. The roll-shaped optical element according to claim 6, wherein the predetermined function is the function of (A1) below. (A1) When circularly polarized light is incident on the optical element as incident light, the function of diffracting the incident light and inverting the phase of the incident light.

8. A sheet-shaped optical element obtained by cutting out a sheet-shaped optical element from the roll-shaped optical element according to any one of Claims 1 to 7 so as to include at least one composite region.

9. An inspection method for the following roll-shaped optical element; "A roll-shaped optical element in which an optical element is wound, The optical element has a first direction that is a direction orthogonal to the length direction of the roll and a second direction that is a direction parallel to the length direction of the roll, The optical element has a substrate, an alignment layer, and a liquid crystal layer in this order, The surface of the alignment layer on the liquid crystal layer side has a composite region combining a first alignment region and a second alignment region arranged on the second direction side of the first alignment region, In the composite region, the second alignment region is arranged on an extension line in the second direction from an arbitrary position of the first alignment region, A plurality of the composite regions are arranged in the second direction, The optical element has a predetermined function, The predetermined function is exhibited by a region corresponding to the first alignment region, A roll-shaped optical element in which the region corresponding to the second alignment region is a dummy region that does not exhibit the predetermined function."; A first step of setting a pass criterion value for a predetermined optical characteristic of the second alignment region; A second step of cutting out at least a part of the second alignment region from the roll-shaped optical element and measuring the predetermined optical characteristic; A third step of determining whether or not the measured value in the second step satisfies the pass criterion value set in the first step, and an inspection method for a roll-shaped optical element.

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