Optical element and device including optical element

Abstract

To provide an optical element with improved in-plane uniformity of phase difference.SOLUTION: An optical element 100 comprises a pattern layer 20 and a liquid crystal layer 30, the pattern layer 20 includes a first surface 20a and a second surface 20b opposite to the first surface 20a, and the liquid crystal layer 30 is formed on the first surface 20a of the pattern layer 20. The first surface 20a has a first direction A1 and a second direction A2 orthogonal to the first direction A1, the first surface 20a has a plurality of recesses arranged in a predetermined pattern, the recesses are arranged at a predetermined pitch in the first direction A1, and the first surface 20a has a region having a different pitch of the recesses in the first direction A1. When a recess included in a region having a short pitch is a first recess 21, a recess included in a region having a long pitch is a second recess 22, an average depth of the first recess 21 is D1, and an average depth of the second recess 22 is D2, D1<D2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to optical elements and devices including said optical elements. [Background technology]

[0002] 2. Description of the Related Art There are technical fields in which optical elements are used to change the polarization state of light or the traveling direction of light.

[0003] The optical element described above is used in, for example, a light control device. In recent years, development of devices equipped with optical sensors has progressed in the fields of personal authentication and autonomous driving of vehicles. Examples of devices equipped with optical sensors include face authentication devices and LiDAR (light detection and ranging). Optical elements may also be used in such devices equipped with optical sensors. In addition, display devices for displaying virtual reality (VR), augmented reality (AR), and mixed reality (MR) have been released in recent years. In this specification, technologies for displaying non-existent reality, such as VR, AR, and MR, are referred to as "cross reality (XR)." Optical elements may also be used in display devices for cross reality.

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

[0005] Furthermore, an optical element has been proposed that includes a liquid crystal layer on a patterned layer having a predetermined pattern, and has regions in the plane where the orientation pitch of the liquid crystal molecules is different (Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 038260 [Patent Document 2] Japanese Patent Publication No. 2022-147451 [Patent Document 3] Special Publication No. 2019-536101 Summary of the Invention [Problem to be solved by the invention]

[0007] The optical element of Patent Document 3 has regions in its plane where the orientation pitch of the liquid crystal molecules is different, thereby making it possible to efficiently change the wavelength of diffracted light within the plane. However, with the optical element of Patent Document 3, there were frequent cases where the theoretical optical characteristics could not be obtained in some parts of the plane. [Means for solving the problem]

[0008] As a result of research to solve the above problem, the inventors have discovered that the reason why theoretical optical characteristics cannot be obtained in a part of the plane is because the retardation of the liquid crystal layer varies in a part of the plane. More specifically, the inventors have discovered that the retardation of the liquid crystal layer varies in a part of the plane because the retardation tends to be high in a region where the orientation pitch of the liquid crystal molecules is large and the retardation tends to be low in a region where the orientation pitch of the liquid crystal molecules is small. The inventors have then completed an optical element that can improve the in-plane uniformity of the retardation in an optical element that includes a liquid crystal layer on a pattern layer having a predetermined pattern and has regions in the plane where the orientation pitch of the liquid crystal molecules varies.

[0009] This disclosure provides the following: <1> ~ <2> The present invention provides optical elements and devices. <1> An optical element having a patterned layer and a liquid crystal layer, the pattern layer has a first surface and a second surface opposite the first surface; the liquid crystal layer is formed on the first surface of the patterned layer; the first surface has a first direction and a second direction orthogonal to the first direction; The first surface has a plurality of recesses arranged in a predetermined pattern. The recesses are arranged at a predetermined pitch in the first direction. The pitch is the length until the direction of the recess changes stepwise by 180 degrees. The first surface has regions where the pitch of the recesses is different in the first direction. When the pitch of the recesses in the region with a short pitch is defined as P1, the pitch of the recesses in the region with a long pitch is defined as P2, the recesses included in the region with a short pitch are defined as the first recesses, the recesses included in the region with a long pitch are defined as the second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, an optical element in which D1 < D2. <2> <1> The device including the optical element described in.

Effect of the Invention

[0010] The optical element of the present disclosure includes a liquid crystal layer on a pattern layer having a predetermined pattern and has regions with different alignment pitches of liquid crystal molecules in the plane. In this optical element, the in-plane uniformity of the phase difference can be improved. The device of the present disclosure can provide a device including an optical element having good in-plane uniformity of the phase difference.

Brief Description of the Drawings

[0011] [Figure 1] It is a cross-sectional view showing an embodiment of the optical element of the present disclosure. [Figure 2] It is a plan view showing an embodiment of the first surface of the pattern layer of the optical element of the present disclosure. [Figure 3] It is a plan view showing another embodiment of the first surface of the pattern layer of the optical element of the present disclosure.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the optical element of the present disclosure will be described. In this specification, "phase difference" means the in-plane phase difference at a wavelength of 532 nm unless otherwise specified.

[0013] [Optical element] The optical element of the present disclosure is an optical element having a pattern layer and a liquid crystal layer, the pattern layer has a first surface and a second surface opposite to the first surface, the liquid crystal layer is formed on the first surface of the pattern layer, the first surface has a first direction and a second direction orthogonal to the first direction, the first surface has a plurality of recesses arranged in a predetermined pattern, the recesses are arranged at a predetermined pitch in the first direction, the pitch is the length until the direction of the recess changes stepwise by 180 degrees, the first surface has regions where the pitch of the recesses is different in the first direction, When the pitch of the recesses in the region with a short pitch is defined as P1, the pitch of the recesses in the region with a long pitch is defined as P2, the recesses included in the region with a short pitch are defined as the first recesses, the recesses included in the region with a long pitch are defined as the second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, then D1 < D2.

[0014] FIG. 1 is a cross-sectional view showing an embodiment of the optical element of the present disclosure. The optical element 100 in FIG. 1 has a pattern layer 20 and a liquid crystal layer 30. In FIG. 1, the pattern layer 20 has a first surface 20a and a second surface 20b opposite to the first surface. In FIG. 1, the liquid crystal layer 30 is formed on the first surface 20a of the pattern layer 20. In FIG. 1, the pattern layer 20 has, as a plurality of recesses on the first surface 20a, a first recess 21 and a second recess 22. The optical element 100 in FIG. 1 has a substrate 10 on the side opposite to the liquid crystal layer 30 of the pattern layer 20. In FIG. 1, the symbol D1 indicates the depth of the first recess 21, and the symbol D2 indicates the depth of the second recess 22. In FIG. 1, the relationship is D1 < D2. In FIG. 1, the symbol t1 indicates the thickness of the liquid crystal layer formed in the first recess 21, and the symbol t2 indicates the thickness of the liquid crystal layer formed in the second recess 22. Fig. 1 is a schematic cross-sectional view. That is, the scale of each layer constituting optical element 100 and the scale of the recessed portion on the first surface are schematic for ease of illustration and differ from the actual scale. The same applies to other figures besides Fig. 1.

[0015] FIG. 2 is a plan view illustrating one embodiment of a first surface of a patterned layer of an optical element of the present disclosure. In FIG. 2, the first surface of the pattern layer has a first direction A1 and a second direction A2 perpendicular to the first direction. In FIG. 2, the first surface has a plurality of recesses 21, 22 arranged in a predetermined pattern. In FIG. 2, the recesses 21, 22 are arranged at a predetermined pitch in the first direction A1. In FIG. 2, symbols P1 and P2 indicate the pitch. P1 and P2 indicate the length over which the direction of the recesses 21, 22 changes stepwise by 180 degrees in the first direction A1. In FIG. 2, the lengths of P1 and P2 are different. That is, in FIG. 2, the first surface has regions in the first direction A1 where the recesses have different pitches. In Fig. 2, there are two regions where the directions of the recesses 21 and 22 change stepwise by 180 degrees, but the number of regions is not limited to two. In Fig. 2, the number of regions is reduced for ease of illustration.

[0016] FIG. 3 is a plan view showing another embodiment of the first surface of the pattern layer of the optical element of the present disclosure. In FIG. 3, the first surface of the pattern layer has a first direction A1 and a second direction A2 perpendicular to the first direction. In FIG. 3, the first surface has a plurality of recesses 21, 22 arranged in a predetermined pattern. In FIG. 3, the recesses 21, 22 are arranged at a predetermined pitch in the first direction A1. In FIG. 3, symbols P1 and P2 indicate the pitch. P1 and P2 indicate the lengths over which the direction of the recesses 21, 22 changes stepwise by 180 degrees in the first direction A1. In FIG. 3, the lengths of P1 and P2 are different. That is, in FIG. 3, the first surface has regions in the first direction A1 where the recesses have different pitches. In Fig. 3, the number of regions where the directions of the recesses 21 and 22 change stepwise by 180 degrees is three, but the number of regions is not limited to three. In Fig. 3, the number of regions is reduced for ease of illustration.

[0017] <Pattern layer> The pattern layer has a first surface and a second surface opposite the first surface. A liquid crystal layer is formed on the first surface of the pattern layer. The presence of the pattern layer makes it easier for liquid crystal molecules in the liquid crystal layer to align along a predetermined pattern. The shape of the second surface 20b of the pattern layer is not particularly limited. In order to improve the adhesion between the second surface side of the pattern layer and other members such as a substrate, the second surface of the pattern layer is preferably flat.

[0018] The pattern layer has the following configurations 1 to 5. Configuration 1: The first surface of the pattern layer has a first direction and a second direction perpendicular to the first direction. Configuration 2: The first surface has a plurality of recesses arranged in a predetermined pattern. Configuration 3: The recesses are arranged at a predetermined pitch in the first direction, the pitch being a length over which the direction of the recesses changes stepwise by 180 degrees. Configuration 4: The first surface has a region in which the pitch of the recesses varies in the first direction. Configuration 5: When the pitch of the recesses in the short pitch region is defined as P1, the pitch of the recesses in the long pitch region is defined as P2, the recesses included in the short pitch region are defined as first recesses, the recesses included in the long pitch region are defined as second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, <D2である。

[0019] (Configuration 1) As shown in FIGS. 2 and 3, the first surface of the pattern layer has a first direction A1 and a second direction A2 perpendicular to the first direction.

[0020] (Configuration 2) As shown in FIGS. 2 and 3, the first surface has a plurality of recesses 21, 22 arranged in a predetermined pattern.

[0021] The predetermined pattern in configuration 2 refers to a pattern formed by recesses when the first surface of the pattern layer is viewed in plan view. Examples of the predetermined pattern include semicircular, circular, and arc-shaped patterns.

[0022] The predetermined pattern may be formed by a shape in plan view connecting a plurality of recesses, as shown in FIG. 2. When the predetermined pattern is formed by a shape in plan view connecting a plurality of recesses, it is easy to prevent the individual recesses of the pattern layer from becoming too large, making it easier to form the pattern layer stably. Furthermore, stabilizing the pattern layer makes it easier to align the liquid crystal molecules on the pattern layer. In FIG. 2, the individual recesses forming the predetermined pattern have approximately the same length in the first direction. However, the individual recesses forming the predetermined pattern may have different lengths in the first direction.

[0023] When forming a predetermined pattern by connecting a plurality of recesses in a plan view, it is preferable to prevent the direction of adjacent recesses from changing suddenly in order to facilitate alignment of liquid crystal molecules. Therefore, when forming a predetermined pattern by connecting a plurality of recesses in a plan view, the number of recesses constituting the predetermined pattern is preferably 3 to 179, more preferably 4 to 150, more preferably 5 to 100, and even more preferably 10 to 50. In an embodiment having a domain unit as shown in Figure 2, it is preferable that the number of domains constituting the domain unit is the number described above. In the configuration requirements described herein, when multiple upper limit options and multiple lower limit options are shown, it is assumed that the embodiments described refer to ranges that combine one selected from the upper limit options with one selected from the lower limit options. For example, embodiments of ranges for the number of recesses that constitute the predetermined pattern described above include 3 to 179, 3 to 150, 3 to 100, 3 to 50, 4 to 179, 4 to 150, 4 to 100, 4 to 50, 5 to 179, 5 to 150, 5 to 100, 5 to 50, 10 to 179, 10 to 150, 10 to 100, and 10 to 50.

[0024] The predetermined pattern may be formed by the shape of a single recess in plan view, as shown in FIG. The optical element of the present disclosure may have, on its first surface, a predetermined pattern formed by a planar view shape connecting multiple recesses (Figure 2) and a pattern formed by the planar view shape of a single recess.

[0025] In the first direction, the recesses adjacent to each other may be arranged with a gap therebetween or may be arranged in contact with each other.

[0026] (Configuration 3) 2 and 3, the recesses 21, 22 are arranged at a predetermined pitch in the first direction A1. The pitch is the length over which the direction of the recesses 21, 22 changes stepwise by 180 degrees.

[0027] In this specification, the "direction of the recess" refers to the extension direction of the recess. The direction of a tangent to the shape of the recess in plan view can be considered to be the extension direction of the recess. In the case of a recess having a shape in plan view that satisfies the following (1) to (3), the extending direction of the first line and the second line can be regarded as the extending direction of the recess. In the case where the first line and the second line are curved lines such as arcs, the extending direction of the recess can be regarded as the extending direction of the recess. (1) It has a pair of parallel lines, a first line and a second line. (2) A line is provided connecting the ends of the first line and the second line on the same side. (3) The length of the first line and the second line is greater than the length of the line connecting the ends of the line (2)

[0028] The first and second lines in (1) above are preferably substantially parallel. "Substantially parallel" means that the angle between the first and second lines is 3.0 degrees or less. The angle between the first and second lines is preferably 1.0 degrees or less, and more preferably 0.5 degrees or less. The first and second lines in (1) above preferably have substantially equal lengths. "Substantially equal lengths" means that the ratio of the length of the first line to the length of the second line is 0.80 or more and 1.20 or less. The ratio is preferably 0.90 or more and 1.10 or less, and more preferably 0.95 or more and 1.05 or less.

[0029] The liquid crystal molecules in the liquid crystal layer tend to align along the direction of the recesses. Therefore, by arranging the recesses 21 and 22 at a predetermined pitch in the first direction A1, the liquid crystal molecules in the liquid crystal layer also tend to align at a predetermined pitch.

[0030] 2 and 3, the symbols P1 and P2 indicate pitches. The number of regions where the direction of the recesses 21, 22 changes stepwise by 180 degrees is two in FIG. 2 and three in FIG. 3, but it is preferable that the number of such regions is infinite across the entire A1 direction of the optical element.

[0031] The pitch length of the recesses cannot be generalized as it varies depending on the desired optical properties, but is preferably 0.2 μm or more and 10,000 μm or less, more preferably 0.4 μm or more and 8,000 μm or less, and even more preferably 0.6 μm or more and 6,000 μm or less.

[0032] The first surface may have a boundary between the predetermined patterns in the first direction. Reference numeral 27 in Fig. 2 denotes the boundary. At the boundary, for example, a convex portion parallel to the second direction is arranged. Because liquid crystal is difficult to align at the convex portion, having a convex portion at the boundary makes it easier to clarify the pattern transition in the first direction. In Figure 2, reference numeral 27-2 denotes a convex portion, and reference numeral 27-1 denotes a concave portion at the boundary. The width of the convex portion at the boundary is preferably more than 0 nm and not more than 100 nm, more preferably 2 nm or more and 75 nm or less, and even more preferably 4 nm or more and 50 nm or less. The height of the convex portion at the boundary is 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.

[0033] In order to facilitate the formation of a predetermined pattern over the entire first surface, it is preferable that a plurality of recesses 21, 22 are arranged in a second direction perpendicular to the first direction (FIGS. 2 and 3).

[0034] The recesses arranged in the second direction preferably have congruent or similar planar shapes. This configuration makes it easier to peel the pattern layer from the shaping plate, thereby facilitating the formation of the pattern layer more stably. "Congruent" means that when the recesses are moved in the second direction, the planar shapes of the recesses completely match. "Similar" means that when the recesses are moved in the second direction, the area of ​​the planar shapes of the recesses matches 90% or more. The area matching rate is preferably 95% or more, more preferably 97% or more, and even more preferably 99% or more. When forming recesses by electron beam lithography or the like, distortion may occur at the ends of the recesses. For this reason, when the length of the recesses in the first direction is taken as 100%, 10% of both ends are excluded to determine whether they are congruent or similar.

[0035] In the second direction, the distance between the ends of adjacent recesses is not particularly limited, but is preferably 5 nm or more and 5000 μm or less, more preferably 10 nm or more and 4000 μm or less, and even more preferably 15 nm or more and 3000 μm or less.

[0036] (Configuration 4) As shown in FIGS. 2 and 3, the first surface has a region where the pitch of the recesses varies in the first direction. 2 and 3, the lengths of P1 and P2 are different. That is, in Figures 2 and 3, the first surface has regions where the pitches of the recesses 21 and 22 are different in the first direction A1.

[0037] In configuration 4, the first surface is specified to have regions in which the pitch of the recesses varies in the first direction. Liquid crystal molecules in the liquid crystal layer tend to align along the extension direction of the recesses. Therefore, when a liquid crystal layer is formed on a pattern layer having configuration 4, regions in which the alignment pitch of the liquid crystal molecules varies tend to be formed within the plane of the liquid crystal layer. The "alignment pitch of liquid crystal molecules" refers to the length over which the alignment direction of the liquid crystal molecules changes stepwise by 180 degrees. Regions with different alignment pitches of liquid crystal molecules can exhibit different optical properties. Therefore, by having configuration 4, the optical element can exhibit different optical properties within the plane. For example, by having configuration 4, the optical element can change the angle of diffracted light within the plane.

[0038] The functions that are realized by gradually changing the alignment direction of the liquid crystal molecules in the liquid crystal layer by 180 degrees include the following functions (X1) and (X2). (X1) A function of diffracting and inverting the phase of incident light when circularly polarized light is incident as the incident light. (X2) When natural light or linearly polarized light is incident as incident light, the function of diffracting the incident light and separating the incident light into right-handed circularly polarized light and left-handed circularly polarized light.

[0039] The orientation of the liquid crystal molecules in the liquid crystal layer tends to vary depending on the arrangement pitch of the liquid crystal molecules. Specifically, the liquid crystal molecules in the region with a long pitch tend to have good orientation, while the liquid crystal molecules in the region with a short pitch tend to have reduced orientation. The inventors of the present invention have found that while the optical element having Configuration 4 can exhibit different optical properties in the plane, the difference in the orientation of the liquid crystal molecules in the plane tends to make the retardation non-uniform in the plane, resulting in a problem that the theoretical optical properties cannot be obtained in a part of the plane. As a result of research to solve the above problems, the inventors of the present invention have found that when having Configuration 4, by setting a predetermined relationship between the pitch and the depth of the recesses, the in-plane uniformity of the retardation of the optical element can be improved, and the above problems can be solved.

[0040] (Configuration 5) In Configuration 5, when the pitch of the recesses in the region with a short pitch is defined as P1, the pitch of the recesses in the region with a long pitch is defined as P2, the recesses included in the region with a short pitch are defined as the first recesses, the recesses included in the region with a long pitch are defined as the second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, it is specified that D1 < D2.

[0041] In Configuration 5, it is specified that the relationship is D1 < D2. That is, in Configuration 5, it is specified that the average depth D2 of the second recesses included in the region with a long pitch is deeper than the average depth D1 of the first recesses included in the region with a short pitch. As described above, liquid crystal molecules in a region with a long pitch tend to have good alignment, while liquid crystal molecules in a region with a short pitch tend to have reduced alignment. Therefore, in the liquid crystal layer, the region with a long pitch has a large retardation, and the region with a short pitch tends to have a small retardation. Thus, when the pattern layer has Configuration 4, the in-plane uniformity of the retardation is likely to decrease. However, even when the pattern layer has Configuration 4, by further having Configuration 5, the in-plane uniformity of the retardation can be improved. The reasons for improving the in-plane uniformity of the retardation by Configuration 5 are as follows (1) and (2). As in (1) and (2) below, the optical element of the present disclosure deliberately reduces the alignment of liquid crystal molecules in a region with a long pitch by Configuration 5. Therefore, the optical element of the present disclosure can make the alignment of liquid crystal molecules in a region with a long pitch and a region with a short pitch approach equality, and it is easy to improve the in-plane uniformity of the retardation of the optical element. (1) When comparing the alignment of liquid crystal molecules in the thickness direction of the liquid crystal layer, the bottom shows a tendency to have better alignment than near the surface. Therefore, the deeper the depth of the concave portion, the more likely the alignment of liquid crystal molecules will decrease near the surface of the liquid crystal layer. (2) As the depth of the concave portion increases, there is a tendency for it to be more difficult to stably form the concave portion. Also, as the depth of the concave portion increases, it becomes more difficult to stably form the liquid crystal layer on the pattern layer. Therefore, the deeper the depth of the concave portion, the more likely the alignment of liquid crystal molecules in the liquid crystal layer will be disturbed, resulting in a decrease in alignment.

[0042] When normalizing the number of all combinations of regions where the pitches of the concave portions are different from each other to 100, the ratio of combinations satisfying D1 < D2 is preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, and most preferably 100% on a count basis.

[0043] The depth of each individual concave portion is not particularly limited, but is 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. Note that the depth of each individual concave portion may vary depending on the location. By making the recess depth 2 nm or more, it becomes easier to align the liquid crystal molecules along the recesses, and by making the recess depth 200 nm or less, it becomes easier to peel the pattern layer from the shaping plate, making it easier to form the pattern layer more stably. The depth of the recess is calculated from a photograph of the vertical cross section of the optical element taken with a scanning electron microscope under the following conditions: <Imaging conditions> Acceleration voltage: 5.0 kV Emission current: 5.0μA Probe current: High Detector: SE(U) WD:8mm Condenser lens 1:5.0 Condenser lens 2:1.0 Tilt function of the document table: Enter the tilt angle "0.0"

[0044] In this specification, the average depth D1 of the first recess is calculated by obtaining the above-mentioned vertical cross sections at any 10 locations of the recesses that make up the first recess and averaging the maximum depth of the first recess in each vertical cross section. In this specification, the average depth D2 of the second recess is calculated by obtaining the above-mentioned vertical cross sections at any 10 locations of the recesses that make up the second recess and averaging the maximum depth of the second recess in each vertical cross section.

[0045] In order to more easily improve the in-plane uniformity of the retardation of the optical element, D1 / D2 is preferably 0.24 or more and 0.97 or less.

[0046] In the optical element of the present disclosure, when the average uniaxial length of the first recess is defined as S1 and the average uniaxial length of the second recess is defined as S2, it is preferable that D1 / S1 and D2 / S2 satisfy the following relationship: 0.1≦D1 / S1≦10.0 0.1≦D2 / S2≦10.0

[0047] If D1 / S1 and D2 / S2 are less than 0.1, the length of the minor axis of the recesses is too long, which may make it difficult for the liquid crystal molecules to align along the recesses. Furthermore, if D1 / S1 and D2 / S2 are more than 10.0, it becomes difficult to stably form a patterned layer, and therefore difficult to stably form a liquid crystal layer on the patterned layer. Therefore, by setting D1 / S1 and D2 / S2 within the above ranges, it becomes easier to achieve good alignment of the liquid crystal molecules.

[0048] In this specification, the average length S1 in the minor axis direction of the first recess is calculated by averaging the lengths in the minor axis direction of 10 arbitrary locations of the recesses constituting the first recess. The 10 locations are selected so as not to be biased. In this specification, the average length S2 of the second recess in the minor axis direction is calculated by averaging the lengths of 10 arbitrary positions of the recess constituting the second recess in the minor axis direction. The 10 positions are selected so as not to be biased.

[0049] In this specification, the conditions for calculating or determining from the planar shape of the pattern layer, such as P1, P2, S1, and S2, are calculated or determined from a photograph of the first surface of the pattern layer taken with a scanning electron microscope. The scanning electron microscope is used to take images under the following conditions: <Imaging conditions> Acceleration voltage: 5.0 kV Emission current: 5.0μA Probe current: High Detector: SE(U) WD:8mm Condenser lens 1:5.0 Condenser lens 2:1.0 Tilt function of the document table: Enter the tilt angle "0.0"

[0050] In order to more easily improve the in-plane uniformity of the retardation of the optical element, it is preferable that P1, P2, D1, and D2 in the optical element of the present disclosure satisfy the following formulas. 0.00005≦(P1 / D1) / (P2 / D2)≦2

[0051] The first surface of the optical element of the present disclosure preferably has the following configurations B1 and B2: By having the following configurations B1 and B2, the pattern layer can be more stably formed, making it easier to improve the in-plane uniformity of the retardation. B1: The pitch of the recesses is configured to gradually increase from one end to the other end in the first direction. B2: The average depth of the recesses is configured to gradually increase from one end to the other end in the first direction.

[0052] The first surface may have the following domain units: <Configuration with domain units> the first surface has a plurality of domains arranged in the first direction; each of the plurality of domains has a plurality of recesses arranged in the second direction; The domains form a domain unit in which a predetermined number of domains are assembled, The predetermined pattern is formed by a shape in plan view that connects a recess at one end of the domain unit in the first direction to a recess at the other end.

[0053] FIG. 2 is a plan view of an embodiment in which the first surface has domain units. In Fig. 2, the first surface has a plurality of domains arranged in a first direction A1. Reference numerals 25a, 25b, 25c, 26a, 26b, and 26c in Fig. 2 indicate the plurality of domains arranged in the first direction. Reference numerals S1a, S1b, and S1c in Fig. 2 indicate the lengths of the first recesses in the minor axis direction, and reference numerals S2a, S2b, and S2c in Fig. 2 indicate the lengths of the second recesses in the minor axis direction. In Fig. 2, the domains form a domain unit, which is an assembly of a predetermined number of domains. Also, in Fig. 2, the first surface has a plurality of domain units in a first direction. Reference numerals 25 and 26 in Fig. 2 correspond to the domain units. In Figure 2, the number of domains that make up a domain unit is three, but the number of domains that make up a domain unit is not limited to three. In Figure 2, the number of domains that make up a domain unit is reduced to make the illustration easier. In FIG. 2, each of the domains has a plurality of recesses 21, 22 arranged in a second direction perpendicular to the first direction. In FIG. 2, a boundary 27 is disposed between the domain units 25 and 26 .

[0054] The pattern layer may have a thickness below the recesses. The average thickness below the recesses is preferably 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 15 μm or less, and even more preferably 2 μm or more and 7 μm or less.

[0055] <<Materials for pattern layers>> The pattern layer preferably contains a resin, and the proportion of the resin in the pattern layer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total solid content of the pattern layer.

[0056] -resin- The resin for the pattern layer may be a thermoplastic resin or a cured product of a curable resin composition, among which a cured product of a curable resin composition is preferred in order to improve strength. 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 even more preferably 90% by mass or more, based on the total solid content of the pattern layer.

[0057] Examples of the cured product of the curable resin composition include a cured product of a heat-curable resin composition and a cured product of an ionizing radiation-curable resin composition, and among these, a cured product of an ionizing radiation-curable resin composition is preferred.

[0058] 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 groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups. The ionizing radiation curable resin is preferably a compound having an ethylenically unsaturated bond group.In addition, from the viewpoint of preventing the pattern layer from being damaged during the manufacturing process of the optical element, the ionizing radiation curable resin is more preferably a compound having two or more ethylenically unsaturated bond groups, and among them, a polyfunctional (meth)acrylate compound having two or more ethylenically unsaturated bond groups is even more preferred.The polyfunctional (meth)acrylate compound can be either a monomer or an oligomer. Ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Typically, ultraviolet (UV) rays or electron beams (EB) are used, but other types of electromagnetic waves such as X-rays and gamma rays, as well as charged particle beams such as alpha rays and ion beams can also be used.

[0059] Among the polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate. 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, and isocyanuric acid-modified tri(meth)acrylate. The (meth)acrylate monomer may have a part of its molecular skeleton modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc. may also be used.

[0060] Examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylates can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate. Preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting a tri- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with (meth)acrylic acid; (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a polybasic acid and (meth)acrylic acid; and (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a phenol and (meth)acrylic acid. The above ionizing radiation curable resins can be used alone or in combination of two or more.

[0061] When the ionizing radiation curable resin is an ultraviolet curable resin, the resin layer forming coating liquid preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. The photopolymerization initiator may be one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzil dimethyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, and the like. The photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and increase the curing rate, and examples thereof include one or more selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc.

[0062] The pattern 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 impaired.

[0063] <<Method for forming pattern layer>> The pattern layer can be formed, for example, by shaping the unshaped pattern layer using a plate having a shape complementary to the surface shape of the first surface. More specifically, the pattern layer can be formed, for example, by the following steps 1 and 2.

[0064] Step 1: A step of applying a coating liquid for forming a pattern layer containing a resin onto a substrate to form a layer containing a 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 first surface of the pattern layer.

[0065] When the coating liquid for forming a pattern layer contains a solvent, it is preferable to dry the solvent in step 1.

[0066] When a curable resin is used as the resin, it is preferable to use a pattern layer-forming coating liquid containing a curable resin composition as the pattern layer-forming coating liquid 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 a coating liquid for forming a pattern layer containing an ionizing radiation curable resin composition is used as the coating liquid for forming a pattern layer in step 1, it is preferable to irradiate the layer with ionizing radiation simultaneously with the shaping in step 2 to cure the ionizing radiation curable resin composition contained in the shaped layer.

[0067] When another layer such as a primer layer is present between the substrate and the pattern layer, it is preferable to carry out a step of forming the other layer on the substrate before step 1.

[0068] The plate used in step 2 can be produced by general-purpose means such as laser lithography, electron beam lithography, or focused ion beam. Means for forming recesses of varying depth within the surface include changing the number of etchings within the surface, or changing the etching time within the surface. The uneven shape to be formed on the surface of the plate can be designed using general-purpose simulation software. It is also preferable to produce many copies of the plate produced by the above-mentioned means, and then arrange the many copies to form a multi-faceted plate. Plate duplication can be carried out by general-purpose means such as electroforming. The shape of the plate may be flat, cylindrical, etc. A cylindrical plate is preferred in that it can be processed by roll-to-roll and has excellent productivity.

[0069] <Liquid crystal layer> In the optical element of the present disclosure, the liquid crystal layer is formed on the first surface of the pattern layer. The liquid crystal molecules of the liquid crystal layer tend to align along the recesses of the pattern layer. Therefore, the liquid crystal molecules of the liquid crystal layer tend to align at a predetermined pitch in the first direction.

[0070] The direction of the slow axis and / or the direction of the fast axis of the liquid crystal layer varies along the alignment direction of the liquid crystal molecules. Therefore, a liquid crystal layer having an alignment region in which the direction of the slow axis and / or the direction of the fast axis change stepwise by 180 degrees along a first direction can be said to have an alignment region in which the alignment direction of the liquid crystal molecules changes stepwise by 180 degrees along the first direction. Therefore, whether or not a liquid crystal layer has an alignment region in which the alignment direction of the liquid crystal molecules changes stepwise by 180 degrees along the first direction can be determined by measuring the direction of the slow axis and / or the direction of the fast axis. An example of a device capable of measuring the direction of the slow axis and / or the direction of the fast axis of a liquid crystal layer is a two-dimensional birefringence evaluation system (product name: WPA-Micro) manufactured by Photonic Lattice. In this specification, the slow axis means the in-plane direction in which the refractive index is greatest, and the fast axis means the in-plane direction perpendicular to the slow axis.

[0071] The liquid crystal layer can be formed, for example, by applying a liquid crystal layer-forming coating liquid containing a liquid crystal compound onto the pattern layer, and then drying and curing the liquid crystal layer as necessary.

[0072] The liquid crystal compound may be at least one selected from rod-shaped liquid crystal compounds such as nematic liquid crystal compounds and smectic liquid crystal compounds, cholesteric liquid crystal compounds, discotic liquid crystal compounds (disco-shaped liquid crystal compounds), and the like. The liquid crystal layer may further contain a chiral agent in addition to the liquid crystal compound. For example, a liquid crystal layer containing a nematic liquid crystal compound and a chiral agent has an alignment in which the direction of the liquid crystal compound molecules is rotated when the liquid crystal layer is viewed in a plane. However, the direction of the liquid crystal compound molecules does not need to be rotated 360 degrees and may be rotated by less than 360 degrees.

[0073] The liquid crystal layer is preferably a homogeneously aligned liquid crystal layer so as to easily impart a predetermined in-plane retardation, and therefore the liquid crystal compound of the liquid crystal layer is preferably a rod-shaped liquid crystal compound.

[0074] The liquid crystal compound is preferably a rod-shaped liquid crystal compound, and is not particularly limited, but examples thereof include the compounds shown in (1) to (28) below.

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] Among liquid crystal compounds, polymerizable rod-shaped liquid crystal materials are preferred. Polymerizable functional groups of polymerizable rod-shaped liquid crystal materials include those that polymerize under the action of ionizing radiation such as ultraviolet light or electron beams, or heat. Specific examples include radically polymerizable functional groups. Examples of radically polymerizable functional groups include functional groups having at least one addition-polymerizable ethylenically unsaturated double bond, and more specific examples include vinyl groups and acrylate groups (a general term including acryloyl groups, methacryloyl groups, acryloyloxy groups, and methacryloyloxy groups), with or without substituents.

[0080] The liquid crystal layer is preferably formed on the entire surface of the first surface of the pattern layer, that is, it is preferable to form the liquid crystal layer also in areas on the first surface of the pattern layer that do not have recesses (Figure 1). The thickness of the liquid crystal layer may be adjusted in accordance with the desired retardation value.

[0081] 1, the symbol T indicates the thickness of the liquid crystal layer formed in the area of ​​the pattern layer that does not have a recess. Also, in FIG. 1, the symbol t1 indicates the thickness of the liquid crystal layer formed in the first recess 21, and the symbol t2 indicates the thickness of the liquid crystal layer formed in the second recess 22. 1 is a schematic diagram, the ratios of T to t1 and t2 are small, but in order to uniformize the in-plane retardation, it is preferable to make T / t1 and T / t2 sufficiently large. Specifically, T / t1 and T / t2 are each preferably 0.909 or more and 0.999 or less, more preferably 0.930 or more and 0.998 or less, and even more preferably 0.950 or more and 0.997 or less.

[0082] The liquid crystal layer may be of a single layer structure or a multi-layer structure, but is preferably of a single layer structure in order to reduce the thickness.

[0083] The liquid crystal layer may have positive wavelength dispersibility or negative wavelength dispersion. Negative wavelength dispersibility is a characteristic in which the phase difference imparted to the transmitted light increases as the wavelength of the transmitted light becomes longer. Positive wavelength dispersibility is a characteristic in which the phase difference imparted to the transmitted light decreases as the wavelength of the transmitted light becomes longer. In this specification, when the in-plane phase difference at a wavelength of 450 nm is defined as Re450 and the in-plane phase difference at a wavelength of 550 nm is defined as Re550, the characteristic where Re450 < Re550 is referred to as negative wavelength dispersibility. In this specification, the characteristic where Re450 > Re550 is referred to as positive wavelength dispersibility.

[0084] In an optical element in which a liquid crystal layer is laminated on a pattern layer, the shape of the pattern layer can be confirmed by, for example, the method of (1) or (2) below. Note that as long as the liquid crystal layer on the pattern layer can be easily removed, the shape of the pattern layer may be confirmed by a method other than the methods of (1) and (2) below. (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, attach a 18 mm cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. to the cut portion, and rub the tape with a rubber 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. Thus, the shape of the pattern layer can be confirmed by peeling off the liquid crystal layer on the pattern layer. (2) Repeat the operation of cutting the optical element as thinly as possible in cross-section by a cross-section cutting method used during cross-section observation such as STEM and taking a cross-section STEM image. By connecting the obtained cross-section STEMs and visualizing them in three dimensions, the shape of the pattern layer can be confirmed.

[0085] <Substrate> The optical element of the present disclosure may have a substrate.

[0086] Various materials can be used as the material for the substrate, but materials with good mechanical properties, optical properties, stability, and processability 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; glass; and the like, with resins being preferred. That is, the substrate is preferably a resin substrate. The in-plane retardation of the substrate is preferably 20 nm or less, more preferably 5 nm or less, even more preferably 3 nm or less, even more preferably 1 nm or less, and most preferably 0 nm. The wavelength λ of light serving as a reference for the retardation is 532 nm.

[0087] The thickness of the substrate can be adjusted appropriately within the range of 5 μm or more and 1000 μm or less. The thickness of the substrate is measured using a general-purpose film thickness measuring device. The thickness of the substrate may be measured at any 10 points, and the average value may be the above-mentioned value.

[0088] The substrate preferably has a total light transmittance according to JIS K7361-1:1997 of 70% or more, more preferably 80% or more, and even more preferably 85% or more. The substrate preferably has a haze according to JIS K7136:2000 of 10% or less, more preferably 5% or less, and even more preferably 3% or less.

[0089] In order to suppress refraction of light at the interface between the substrate and the pattern layer, it is preferable that the refractive index of the pattern layer and the refractive index of the substrate are close to each other. Specifically, the refractive index of the pattern layer / the refractive index of the substrate is preferably 0.97 or more and 1.03 or less, and more preferably 0.99 or more and 1.01 or less. The wavelength λ of light that serves as the reference for the refractive index is 532 nm.

[0090] <Other layers> The optical element of the present disclosure may further include other layers. Examples of other layers include a primer layer for improving adhesion between the substrate and the pattern layer, an antistatic layer, etc. The primer layer is preferably formed between the substrate and the pattern layer, and the antistatic layer is preferably formed on the side of the substrate opposite to the pattern layer.

[0091] <Phase difference> The optical element preferably has an average in-plane retardation of each region having different recess pitches within a predetermined range. When the controlled wavelength is λ [nm], the in-plane retardation of the optical element 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 more preferably (λ / 2) × 0.99 or more and (λ / 2) × 1.01 or less, in any domain unit. By setting the average value of the in-plane retardation of each region of the optical element within the above range, when the optical element is used as a diffractive optical element, for example, the following effects can be achieved. (1) When circularly polarized light is incident on a diffractive optical element, the light is diffracted and the phase of the light is inverted. (2) When natural light or linearly polarized light is incident on a diffractive optical element, the light is diffracted and can be separated into right-handed circularly polarized light and left-handed circularly polarized light.

[0092] The in-plane retardation of each region of the optical element having different recess pitches means the average value of five in-plane retardations excluding the maximum and minimum values ​​from the seven in-plane retardations of each region.

[0093] Examples of in-plane retardation measurement devices include the "AxoStep" product manufactured by AXOMETRICS and the two-dimensional birefringence evaluation system (product name: WPA-Micro) from Photonic Lattice. The former product is suited to measuring a wide area, while the latter is suited to measuring a narrow area.

[0094] The optical element preferably satisfies the relationship of the following formula (1) when comparing the phase differences of regions having different recess pitches. 0.97≦Retardation of one region / Retardation of the other region≦1.03 (1)

[0095] The ratio in the above formula (1) is preferably 0.98 or more and 1.02 or less, and more preferably 0.99 or more and 1.01 or less.

[0096] When the number of all combinations of regions with different recess pitches is normalized to 100, the proportion of combinations that satisfy the above formula (1) is preferably 80% or more by number, more preferably 90% or more, even more preferably 95% or more, and even more preferably 100%.

[0097] <Application> The optical element of the present disclosure can be used, for example, as a diffractive optical element, and can also be used as a component of a light control device. The diffraction angle of light transmitted through a diffractive optical element can be adjusted to a predetermined range. Therefore, for example, by using a diffractive optical element, it is possible to widen or narrow the irradiation range of light. In addition, by using a diffractive optical element, it is possible to impart directionality to light. Furthermore, by causing the light beams transmitted through the diffractive optical element to interfere with each other, it is possible to produce the effects of a lens, a prism, or the like. Due to the above-mentioned effects, the diffractive optical element can be used as a component of devices such as cross reality devices, optical sensors, and laser projectors.

[0098] The diffraction angle θ of a diffractive optical element can be expressed by the following equation, where the pitch of the recesses is x [nm], the wavelength of light is λ [nm], and the angle of incidence of light is θ0. θ and θ0 are angles when the perpendicular direction to the plane of the diffractive optical element is set to 0 degrees. In the equation below, θ0 is the case when the direction is positive from the perpendicular direction. The sign ± is added because, depending on the direction of rotation of the circularly polarized light that is the incident light, the light may be diffracted in a positive direction or a negative direction from the perpendicular direction. sinθ=±(λ / x)+sinθ0

[0099] For example, when the incident angle θ0 is fixed at 0 degrees and the wavelength of light is fixed at 1550 nm, the relationship between the pitch and the diffraction angle is as shown in Table 1 below. [Table 1]

[0100] The diffraction angles in Table 1 are angles when there is one diffractive optical element. If the polarization state is the same, increasing the number of diffractive optical elements increases the diffraction angle as a multiplier of the number of diffractive optical elements. If the diffraction angle at an arbitrary pitch is θ (degrees) and the number of diffractive optical elements is n, the diffraction angle is 2 n-1 ×θ (degrees).

[0101] [Device] The device of the present disclosure includes the optical element of the present disclosure described above.

[0102] Examples of the device include a display device such as a cross reality device, an optical sensor, and a laser projector.

[0103] The disclosure is as follows: <1> ~ <8> Includes. <1> An optical element having a patterned layer and a liquid crystal layer, the pattern layer has a first surface and a second surface opposite the first surface; the liquid crystal layer is formed on the first surface of the patterned layer; the first surface has a first direction and a second direction orthogonal to the first direction; The first surface has a plurality of recesses arranged in a predetermined pattern, the recesses are arranged at a predetermined pitch in the first direction, the pitch is the length until the direction of the recess changes stepwise by 180 degrees, the first surface has regions where the pitch of the recesses is different in the first direction, When the pitch of the recesses in the region with a short pitch is defined as P1, the pitch of the recesses in the region with a long pitch is defined as P2, the recesses included in the region with a short pitch are defined as the first recesses, the recesses included in the region with a long pitch are defined as the second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, an optical element in which D1 < D2. <2> The optical element according to <1>, wherein 0.24 ≦ D1 / D2 ≦ 0.97. <3> When the average length in the uniaxial direction of the first recesses is defined as S1 and the average length in the uniaxial direction of the second recesses is defined as S2, the optical element according to <1> or <2>, wherein D1 / S1 and D2 / S2 satisfy the following relationship. 0.1 ≦ D1 / S1 ≦ 10.0 0.1 ≦ D2 / S2 ≦ 10.0 <4> The optical element according to any one of <1> to <3>, wherein the predetermined pattern is formed by the planar shape of a single recess. <5> The optical element according to any one of <1> to <3>, wherein the predetermined pattern is formed by the planar shape connecting a plurality of recesses. <6> The first surface has a plurality of domains arranged in the first direction, each of the plurality of domains has a plurality of recesses arranged in the second direction within each domain, the domains form a domain unit in which a predetermined number of domains are assembled, The optical element according to any one of <1> to <3>, wherein the predetermined pattern is formed by the planar shape connecting the recesses at one end to the recesses at the other end in the first direction of the domain unit. <7> The optical element according to any one of <1> to <6>, wherein the predetermined pattern is a semi-circular, circular or arc-shaped pattern. <8> <1> ~ <7> 10. A device comprising the optical element according to any one of the preceding items. [Example]

[0104] Next, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples. Note that "parts" and "%" are based on mass unless otherwise specified.

[0105] 1. Measurement and Evaluation The optical elements of the examples and comparative examples were subjected to the following measurements and evaluations. The atmosphere during each measurement and evaluation was a temperature of 23±5°C and a relative humidity of 40% to 65%. Before each measurement and evaluation, the target sample was exposed to the atmosphere for 30 to 60 minutes before measurement and evaluation. The results are shown in Tables 2 to 5.

[0106] 1-1. Planar shape of pattern layer The first surface of the pattern layer of the intermediate body of the optical element of the examples and comparative examples was imaged using a scanning electron microscope (Hitachi High-Technologies Corporation, product name "SU8000") under the following imaging conditions. The intermediate body refers to a laminate having a primer layer and a pattern layer on a substrate. Based on the photographs taken, the pitch of the recesses (P1 and P2), the average length of the first recesses in the uniaxial direction (S1), and the average length of the second recesses in the uniaxial direction (S2) were measured. <Imaging conditions> Acceleration voltage: 5.0 kV Emission current: 5.0μA Probe current: High Detector: SE(U) WD:8mm Condenser lens 1:5.0 Condenser lens 2:1.0 Tilt function of the document table: Enter the tilt angle "0.0"

[0107] 1-2. Depth of recess in pattern layer Vertical cross sections of the optical elements of the examples and comparative examples were photographed using a scanning electron microscope (Hitachi High-Technologies Corporation, product name "SU8000"). The photographing conditions were the same as those in 1-1 above. Then, based on the photographs taken, the average depth (D1) of the first recesses and the average depth (D2) of the second recesses were measured.

[0108] 1-3.In-plane uniformity of phase difference For the optical elements of Example 1 and Comparative Example 1, the following ratios were calculated. Average in-plane retardation of the area where the recess pitch corresponds to the P1 region / Average in-plane retardation of the area where the recess pitch corresponds to the P2 region The above ratio can be regarded as the in-plane uniformity of the retardation. Of Example 1 and Comparative Example 1, the one with excellent in-plane uniformity of the retardation was evaluated as "A," and the one with poor in-plane uniformity of the retardation was evaluated as "C." Similarly, the in-plane uniformity of the retardation of the optical elements of Examples 2 to 60 was compared with that of the optical elements of Comparative Examples 2 to 60.

[0109] 2. Making the plate <Simulation> A simulation tool was used to design the shape of the first surface of the pattern layer. The shape of the first surface was such that regions with short recess pitches were repeatedly formed in a first direction, followed by regions with long recess pitches repeatedly formed in a second direction. Recesses were also repeatedly formed in the second direction. The planar shape of each recess was an arc shape as shown in FIG. 3. The spacing between the ends of adjacent recesses in the first direction was adjusted to 0 nm to 50 nm. The spacing between the ends of adjacent recesses in the second direction was adjusted to 1 nm to 150 nm. Simulations for producing the plates for each of the examples and comparative examples were performed so as to obtain the planar shape of the pattern layer 1-1. <Duplicate mold of the first master> Using a 6-inch square synthetic quartz plate, an electron beam lithography process using an electron beam lithography system and a dry etching system was used to create a quartz first master mold with a surface shape designed in the above simulation, equipped with areas with a short recess pitch. The depth of the recesses was adjusted by the number of etchings and the etching time. Next, an ultraviolet-curable resin was poured into the first master mold, and then a transparent substrate was placed on top of the ultraviolet-curable resin. The resin was then cured by irradiating it with ultraviolet light. The transparent substrate and resin were then peeled off from the first master mold to obtain a first resin plate having a shape complementary to that of the first master mold. Next, a replica mold of the first master mold, which is a mold having a shape complementary to that of the first resin plate, was obtained by electroforming. A plurality of such replica molds were produced. <Duplicate mold of the second master> Using a 6-inch square synthetic quartz plate, an electron beam lithography process using an electron beam lithography system and a dry etching system was used to create a quartz second master mold with a surface shape designed in the above simulation, equipped with areas with a long pitch of recesses. The depth of the recesses was adjusted by the number of etchings and the etching time. Next, an ultraviolet-curable resin was poured into the second master mold, and a transparent substrate was placed on top of the ultraviolet-curable resin. The resin was then cured by irradiating it with ultraviolet light. The transparent substrate and resin were then peeled off from the second master mold to obtain a second resin plate having a shape complementary to that of the second master mold. Next, a replica mold of the second master mold, which is a mold having a shape complementary to that of the second resin plate, was obtained by electroforming. A plurality of such replica molds were produced. <Roll plate> A plurality of replica molds of the first master mold were wound adjacent to each other around a roll, and a plurality of replica molds of the second master mold were wound adjacent to each other around the remaining portion of the roll to produce a roll-shaped plate used in the examples and comparative examples.

[0110] 3. Fabrication of Optical Elements [Example 1] A primer layer having the following formulation was applied onto a substrate (a 40 μm thick cycloolefin polymer, Zeon Corporation's trade name "ZEONOR") and dried to form a primer layer having a thickness of 0.5 μm. Next, a coating liquid for forming a pattern layer having the following formulation was applied onto the primer layer and dried to form a layer containing an uncured resin. Next, using the roll-shaped plate for Example 1 prepared in "2" above, a layer containing uncured resin was formed, and at the same time, ultraviolet light was irradiated from the substrate side (integrated light amount: 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 the primer layer and the pattern layer on the substrate. Next, the following liquid crystal layer forming coating solution was applied onto the pattern layer, dried, and then irradiated with ultraviolet light (integrated light amount: 150 mJ / cm 2 ), a liquid crystal layer was formed. The liquid crystal layer was formed by two coating processes, using a liquid crystal having an in-plane birefringence (Δn) of 0.17 and adjusting the thickness so that the in-plane retardation was 266 nm. The above steps were used to obtain the optical element of Example 1. The optical element of Example 1 was produced by roll-to-roll production.

[0111] <Coating liquid for forming primer layer> Polyolefin resin: 70 parts by weight (Mitsubishi Chemical Corporation, product name: Surflen P-1000) Silica-based lubricant: 5 parts by weight (Manufactured by CIK Nanotech, product name: SIRMIBK15WT%-E65) Methyl ethyl ketone: 25 parts by weight

[0112] <Coating liquid for forming pattern layer> Pentaerythritol triacrylate: 96 parts by mass (Manufactured by Nippon Kayaku Co., Ltd., product name: PET-30) Photopolymerization initiator: 4 parts by mass (IGM, product name: Omnirad184)

[0113] <Liquid crystal layer coating liquid> ·Rod-shaped liquid crystal molecules: 10 parts by mass (LC242 (product name), manufactured by BASF, in-plane birefringence (Δn)=0.17) Photopolymerization initiator: 0.4 parts by mass (IGM, product name: Omnirad184) Methyl ethyl ketone: 89.6 parts by mass

[0114] [Examples 2 to 60], [Comparative Examples 1 to 60] Except for changing the plate for Example 1 to the plate for Examples 2 to 60 and Comparative Examples 1 to 60, a laminate having a primer layer and a pattern layer on a substrate, and an optical element were obtained in the same manner as in Example 1.

[0115] [Table 2]

[0116] [Table 3]

[0117] [Table 4]

[0118] [Table 5]

[0119] As is clear from Tables 2 to 5, it can be confirmed that the optical elements of the examples, which have regions in their planes where the orientation pitch of the liquid crystal molecules is different, can improve the uniformity of the retardation. [Explanation of symbols]

[0120] 10: Base material 20: Pattern layer 20a: First side 20b: Second side 21: First recess 22: Second recess 25, 26: Domain unit 25a, 25b, 25c, 26a, 26b, 26c: Individual domains 27: Boundary 27-1: Concave part of boundary 27-2: Convex 30: Liquid crystal layer 100: Optical elements A1: First direction A2: Second direction P1: Pitch of the recesses in the short pitch area P2: Pitch of the recess in the long pitch area S1a, S1b, S1c, S2a, S2b, S2c: lengths of the first recesses in the minor axis direction

Claims

1. An optical element having a patterned layer and a liquid crystal layer, the pattern layer has a first surface and a second surface opposite the first surface; the liquid crystal layer is formed on the first surface of the patterned layer; the first surface has a first direction and a second direction orthogonal to the first direction; the first surface has a plurality of recesses arranged in a predetermined pattern; the recesses are arranged at a predetermined pitch in the first direction, The pitch is a length over which the direction of the recess changes stepwise by 180 degrees, the first surface has a region in which the pitch of the recesses varies in the first direction, An optical element in which, when the pitch of the recesses in the short pitch region is defined as P1, the pitch of the recesses in the long pitch region is defined as P2, the recesses included in the short pitch region are defined as first recesses, the recesses included in the long pitch region are defined as second recesses, the average depth of the first recesses is defined as D1, and the average depth of the second recesses is defined as D2, D1 < D2.

2. 2. The optical element according to claim 1, wherein 0.24≦D1 / D2≦0.

97.

3. 2. The optical element according to claim 1, wherein, when the average length of the first recess in a uniaxial direction is defined as S1 and the average length of the second recess in a uniaxial direction is defined as S2, D1 / S1 and D2 / S2 satisfy the following relationship: 0.1≦D1 / S1≦10.0 0.1≦D2 / S2≦10.0

4. The optical element according to claim 1 , wherein the predetermined pattern is formed by the shape of a single recess in plan view.

5. The optical element according to claim 1 , wherein the predetermined pattern is formed by a shape in plan view connecting a plurality of recesses.

6. the first surface has a plurality of domains arranged in the first direction; each of the plurality of domains has a plurality of recesses arranged in the second direction; The domains form a domain unit in which a predetermined number of domains are assembled, 2. The optical element according to claim 1, wherein the predetermined pattern is formed by a shape in plan view that connects a recess at one end of the domain unit in the first direction to a recess at the other end.

7. The optical element according to claim 1 , wherein the predetermined pattern is a semicircular, circular, or arc-shaped pattern.

8. An apparatus comprising the optical element according to any one of claims 1 to 7.

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