Antiglare sheet, sheet article, polarizing plate, display device, panel, method for selecting antiglare sheet, and method for producing antiglare sheet

Abstract

This antiglare sheet includes a first surface and a second surface that face each other in a first direction. The antiglare sheet includes an antiglare layer including a surface having recesses and protrusions. The surface having recesses and protrusions faces the side that is opposite from the second surface in the first direction. The antiglare layer includes a plurality of unit element parts constituting the surface having recesses and protrusions. The cross-sectional contour of each of the plurality of unit element parts is convex upward at a center portion and convex downward at peripheral edge portions connected to the center portion, or is convex downward at the center portion and convex upward at the peripheral edge portions.

Description

Antiglare sheet, sheet article, polarizing plate, display device, panel, method for selecting antiglare sheet, and method for manufacturing antiglare sheet

[0001] The present disclosure relates to an antiglare sheet, a sheet article, a polarizing plate, a display device, a panel, a method for selecting an antiglare sheet, and a method for manufacturing an antiglare sheet.

[0002] As disclosed in Patent Document 1, an anti-glare sheet is known. The anti-glare sheet can be applied to a display device, for example. Examples of the display device include a television, a display device incorporated in a notebook PC or a desktop PC, and a display device incorporated in a smartphone or a tablet. The anti-glare sheet is placed in front of a display element. The anti-glare sheet has anti-glare properties. The anti-glare properties are a property that suppresses reflections of lighting and people in the background.

[0003] By strengthening the light scattering function of the antiglare layer, the antiglare properties can be improved. However, as the antiglare properties improve, the clarity decreases. An antiglare sheet with reduced clarity appears cloudy, making it impossible to clearly observe what is behind the antiglare sheet 10, and also impairing the luxurious feel.

[0004] In conventional antiglare sheets, the surface roughness can be adjusted by the size, shape, density, etc. of added particles. Surface roughness can also be adjusted by blasting. However, with conventional antiglare sheets, it has been difficult to adjust the shape of the rough surface with a high degree of freedom. The optimal shape of the rough surface has not been fully explored. As a result, conventional antiglare sheets have not been able to fully achieve both excellent antiglare properties and clarity.

[0005] Patent Document 1: WO2019 / 026466A

[0006] The present disclosure aims to improve the antiglare properties and clarity of an antiglare sheet.

[0007] An anti-glare sheet according to one embodiment of the present disclosure comprises: an anti-glare layer having a first surface and a second surface facing each other in a first direction; and an anti-glare layer including an uneven surface including a plurality of peaks and a plurality of valleys; the uneven surface faces the opposite side to the second surface in the first direction; the anti-glare layer includes a plurality of unit element portions constituting at least a portion of one of the plurality of peaks and the plurality of valleys; the cross-sectional contour of each of the plurality of unit element portions is convex upward in a central portion and convex downward in a peripheral portion connected to the central portion, or is convex downward in the central portion and convex upward in the peripheral portion; each of the plurality of peaks forms a peak of the uneven surface; and each of the plurality of valleys forms a bottom of the uneven surface; and the height of the peaks, which is 5% from the lowest in the positional distribution in the first direction, is lower than the height of the bottoms, which is 5% from the highest in the positional distribution in the first direction.

[0008] a step of confirming that the cross-sectional contour is convex upward at a central portion and convex downward at a peripheral portion connected to the central portion, or that the cross-sectional contour is convex downward at a peripheral portion connected to the central portion; and a step of confirming that the cross-sectional contour is convex downward at the central portion and convex upward at the peripheral portion; and a step of confirming a positional distribution of the peaks in the first direction and a positional distribution of the bottoms in the first direction. A method for selecting an antiglare sheet, comprising a step of confirming that the height of the top portion that is 5% from the lowest in the position distribution in the first direction is lower than the height of the bottom portion that is 5% from the highest in the position distribution in the first direction.

[0009] According to the present disclosure, both the antiglare properties and clarity of an antiglare sheet can be improved.

[0010] FIG. 1 is a diagram for explaining one embodiment, and is a perspective view showing a display device as an application example of an anti-glare sheet. FIG. 2 is a cross-sectional view showing an example of an anti-glare sheet. FIG. 3 is a cross-sectional view showing another example of an anti-glare sheet. FIG. 4 is a plan view showing the in-plane distribution of multiple peaks or multiple valleys included in the anti-glare layer of an anti-glare sheet. FIG. 5 is a perspective view showing unit element portions constituting peaks included in the anti-glare layer shown in FIG. 2. FIG. 6A is a cross-sectional view showing unit element portions constituting peaks included in the anti-glare layer shown in FIG. 2. FIG. 6B is a cross-sectional view showing unit element portions constituting valleys included in the anti-glare layer shown in FIG. 3. FIG. 7 is a cross-sectional view showing peaks and valleys included in the anti-glare layer shown in FIG. 2. FIG. 8 is a perspective view showing an example of a sheet article including an anti-glare sheet. FIG. 9A is a diagram schematically showing a model of an anti-glare sheet in which the surface shape is expressed. FIG. 9B is a diagram schematically showing a model of an anti-glare sheet in which the surface shape is expressed. FIG. 9C is a diagram showing the relationship between the reflection image plane in the far field, the object plane of the anti-glare sheet, and the transmission image plane in the far field. FIG. 10 is a graph showing peak intensity and background intensity. FIG. 11A is a diagram showing the relationship between a unit vector indicating a difference phase and a vector indicating peak intensity. FIG. 11B is a diagram showing the relationship between a unit vector indicating a difference phase and a vector indicating peak intensity. FIG. 12A is a diagram showing an example of a histogram of relative heights Di of apexes or bottoms included in an effective area and a rectangular function fitted to the histogram. FIG. 12B is a diagram showing an example of a histogram of relative phases φi of apexes or bottoms included in an effective area and a rectangular function fitted to the histogram. FIG. 13A is a diagram for explaining the relationship between optical path length difference and phase difference in reflected light. FIG. 13B is a diagram for explaining the relationship between optical path length difference and phase difference in transmitted light. FIG. 14 is a graph showing the relationship between peak-background ratio and phase distribution width. FIG. 15 is a graph showing the relationship between peak-background ratio and height distribution width. FIG. 16 is a diagram corresponding to FIG. 4 and is a plan view showing another example of an in-plane distribution of multiple peaks or multiple valleys. Fig. 17 is a diagram for explaining a process of smoothing a connecting portion of two ridges or unit element portions constituting a ridge. Fig. 18 is a cross-sectional view showing a polarizing plate which is another application example of an antiglare sheet.Fig. 19 is a cross-sectional view showing an example of a panel which is yet another application example of an anti-glare sheet. Fig. 20 is a plan view showing a modified example of peaks, valleys, and unit elements included in an anti-glare sheet. Fig. 21A is a cross-sectional view showing unit elements which constitute peaks included in the anti-glare layer of a conventional anti-glare sheet. Fig. 21B is a cross-sectional view showing unit elements which constitute valleys included in the anti-glare layer of a conventional anti-glare sheet.

[0011] This embodiment relates to the following items <1> to <30>.

[0012] <1> An antiglare layer having a first surface and a second surface opposing each other in a first direction, the antiglare layer including an uneven surface including a plurality of peaks and a plurality of valleys, the uneven surface facing the opposite side to the second surface in the first direction, the antiglare layer including a plurality of unit element portions constituting the uneven surface of at least a part of the plurality of peaks or the plurality of valleys, a cross-sectional outline of each of the plurality of unit element portions being convex upward in a central portion and convex downward in a peripheral portion connected to the central portion, or being convex downward in the central portion and convex upward in the peripheral portion, each of the plurality of peaks forming a peak of the uneven surface, and each of the plurality of valleys forming a bottom of the uneven surface,

[0013] <2> The anti-glare sheet according to <1>, wherein one of the tops and the bottoms constituted by the unit element portions is irregularly arranged in a plane, and a height distribution width Dh (nm) of the one of the tops and the bottoms and a refractive index n of a portion constituting the uneven surface of the anti-glare layer satisfy the following two formulas: (2π / 550)×(n-1)×Dh<2π (2π / 550)×2×Dh≧2π The height distribution width Dh of the tops is a difference between a height that corresponds to 10% of the tops and a height that corresponds to 10% of the bottoms in the positional distribution of the tops in the first direction, and the height distribution width Dh of the bottoms is a difference between a height that corresponds to 10% of the tops and a height that corresponds to 10% of the bottoms in the positional distribution of the bottoms in the first direction.

[0014] <3> The antiglare sheet according to <2>, wherein the following formula is satisfied: (2π / 550)×(n−1)×Dh≦π.

[0015] <4> The anti-glare sheet according to <1>, wherein one of the tops and the bottoms constituted by the unit element portions is irregularly arranged, and the wavelength λ (nm), the height distribution width Dh (nm) of one of the tops and the bottoms, and the refractive index n of a portion constituting the uneven surface of the anti-glare layer satisfy the following two formulas: (2π / λ)×(n-1)×Dh<2π (2π / λ)×2×Dh≧2π The wavelength λ is the wavelength of light incident on the anti-glare sheet with a maximum radiant flux (W), The height distribution width Dh of the tops is the difference between the heights that represent 10% of the tops and the heights that represent 10% of the bottoms in the positional distribution of the tops in the first direction, and The height distribution width Dh of the bottoms is the difference between the heights that represent 10% of the tops and the heights that represent 10% of the bottoms in the positional distribution of the bottoms in the first direction.

[0016] <5> The antiglare sheet according to <4>, wherein the following formula is satisfied: (2π / λ)×(n−1)×Dh≦π.

[0017] <6> The antiglare sheet according to any one of <1> to <5>, wherein in at least some of the plurality of unit element portions, the peripheral portion circumferentially surrounds the central portion.

[0018] <7> The antiglare sheet according to any one of <1> to <6>, wherein the antiglare layer includes a plurality of second unit element portions that constitute at least a part of the other of the plurality of peak portions and the plurality of valley portions, and a cross-sectional outline of each of the plurality of second unit element portions is convex downward in a central portion and convex upward in a peripheral portion connected to the central portion, or is convex upward in the central portion and convex downward in the peripheral portion.

[0019] <8> The antiglare sheet according to any one of <1> to <7>, wherein a dimension of the plurality of peaks or valleys in a second direction perpendicular to the first direction is smaller than a dimension of the plurality of peaks or valleys in a third direction perpendicular to both the first direction and the second direction.

[0020] <9> The antiglare sheet according to any one of <1> to <8>, wherein a dimension of the central portion of each of the plurality of unit element portions in a second direction perpendicular to the first direction is smaller than a dimension of the central portion in a third direction perpendicular to both the first direction and the second direction.

[0021] <10> The antiglare sheet according to any one of <1> to <9>, wherein the transmission haze is 75% or less.

[0022] <11> The antiglare sheet according to any one of <1> to <10>, wherein the image clarity measured by a transmission method using an optical comb having a width of 0.5 mm is 5.0% or more.

[0023] <12> The antiglare sheet according to any one of <1> to <11>, wherein the specular gloss Gs(60) of the first surface at an incident angle of 60° is 8.0% or more.

[0024] <13> The antiglare sheet according to any one of <1> to <12>, wherein the intensity of reflected zero-order light incident at an angle of 0° on the first surface is 20% or less.

[0025] <14> A sheet article comprising a plurality of antiglare sheets according to any one of <1> to <13>.

[0026] <15> The sheet article according to <14>, which is wound around a winding axis.

[0027] <16> A polarizing plate comprising: the antiglare sheet according to any one of <1> to <13>; and a polarizer superimposed on the antiglare sheet.

[0028] <17> A display device comprising: the antiglare sheet according to any one of <1> to <13>; and a display element superimposed on the antiglare sheet.

[0029] <18> A panel comprising: an article to be joined; and the antiglare sheet according to any one of <1> to <13> joined to the article to be joined.

[0030] <19> An anti-glare sheet including a first surface and a second surface opposing each other in a first direction, comprising an anti-glare layer including an uneven surface including a plurality of peaks and a plurality of valleys, the uneven surface facing the opposite side to the second surface in the first direction, the anti-glare layer including a plurality of unit element portions constituting at least a part of one of the plurality of peaks and the plurality of valleys, each of the plurality of peaks forming a peak of the uneven surface and each of the plurality of valleys forming a bottom of the uneven surface, the anti-glare sheet comprising: a step of acquiring a cross-sectional profile of at least a part of the plurality of unit element portions; a step of confirming that the cross-sectional profile is convex upward in a central portion and convex downward in a peripheral portion connected to the central portion, or is convex downward in the central portion and convex upward in the peripheral portion; and a step of acquiring a positional distribution of the peaks in the first direction and a positional distribution of the bottoms in the first direction. A method for selecting an antiglare sheet, comprising a step of confirming that the height of the top portion that is 5% from the lowest in the position distribution in the first direction is lower than the height of the bottom portion that is 5% from the highest in the position distribution in the first direction.

[0031] <20> A method for manufacturing an antiglare sheet, the method comprising: a step of manufacturing an antiglare sheet including a first surface and a second surface opposing each other in a first direction, the antiglare sheet comprising an antiglare layer including an uneven surface including a plurality of peaks and a plurality of valleys, the uneven surface facing the side opposite the second surface in the first direction, the antiglare layer including a plurality of unit element parts constituting at least a part of one of the plurality of peaks and the plurality of valleys, each of the plurality of peaks forming a peak of the uneven surface and each of the plurality of valleys forming a bottom of the uneven surface; and a step of selecting the antiglare sheet by the selection method described in <19>.

[0032] <21> A method for producing the antiglare sheet according to any one of <1> to <13>, comprising: a step of determining a shape of the uneven surface; and a step of shaping the uneven surface.

[0033] <22> The method for manufacturing an antiglare sheet according to <21>, wherein in the step of determining the shape of the uneven surface, it is confirmed that the cross-sectional contour is convex upward in a central portion and convex downward in a peripheral portion connected to the central portion, or is convex downward in the central portion and convex upward in the peripheral portion.

[0034] <23> The method for manufacturing an antiglare sheet according to <21> or <22>, wherein in the step of determining the shape of the uneven surface, cross-sectional contours of the plurality of peaks and valleys are provisionally determined, and the provisionally determined cross-sectional contours are smoothed at a portion where two adjacent peaks, two adjacent valleys, or an adjacent peak and valley are connected among the plurality of peaks and valleys.

[0035] <24> The method for manufacturing an antiglare sheet according to <21> or <22>, wherein in the step of determining the shape of the uneven surface, cross-sectional contours of the plurality of unit element parts are provisionally determined, and the provisionally determined cross-sectional contours are smoothed at a portion where two adjacent unit element parts of the plurality of unit element parts are connected.

[0036] <25> A method for producing the antiglare sheet according to <2> or <4>, comprising: a step of determining the height distribution width Dh; and a step of shaping the uneven surface.

[0037] <26> The method for producing an antiglare sheet according to <25>, wherein in the step of determining the height distribution width Dh, it is confirmed that the following two formulas using a refractive index n of a portion constituting the uneven surface of the antiglare layer are satisfied: (2π / 550)×(n−1)×Dh<2π (2π / 550)×2×Dh≧2π

[0038] <27> A method for producing the antiglare sheet according to <3> or <4>, comprising: a step of determining the height distribution width Dh; and a step of shaping the uneven surface.

[0039] <28> The method for producing an antiglare sheet according to <26>, wherein in the step of determining the height distribution width Dh, it is confirmed that the following two equations are satisfied, using the wavelength λ (nm) of light incident on the antiglare sheet with a maximum radiant flux (W) and the refractive index n of a portion constituting the uneven surface of the antiglare layer: (2π / λ)×(n-1)×Dh<2π (2π / λ)×2×Dh≧2π

[0040] <29> The method for manufacturing an antiglare sheet according to any one of <21> to <28>, further comprising a step of determining an arrangement of a plurality of peaks and a plurality of valleys, wherein in the step of determining the arrangement of the plurality of peaks and a plurality of valleys, the provisionally determined arrangements of the plurality of peaks and a plurality of valleys are adjusted.

[0041] <30> The method for manufacturing an antiglare sheet according to any one of <21> to <29>, further comprising a step of determining an arrangement of a plurality of unit element parts, wherein in the step of determining the arrangement of the plurality of unit element parts, the provisionally determined arrangement of the plurality of unit element parts is adjusted.

[0042] The present embodiment will be described below with reference to the drawings. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for ease of understanding. Configurations shown in some drawings may be omitted in other drawings.

[0043] In this specification, terms such as "parallel," "orthogonal," and "identical," which specify shapes and geometric conditions and their degrees, as well as values ​​of lengths and angles, are not limited to their strict meanings, but are interpreted as including a range of degrees within which similar functions can be expected.

[0044] In this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely on the basis of differences in name. For example, an "antiglare sheet" is not distinguished solely from a member called an antiglare film or an antiglare plate.

[0045] In this specification, the normal direction of a sheet-like (film-like, plate-like) member means a direction parallel to the normal or perpendicular to the sheet surface of the target sheet-like (film-like, plate-like) member. The "sheet surface (film surface, plate surface)" means the surface that coincides with the target sheet-like (film-like, plate-like) member when the target sheet-like (film-like, plate-like) member is observed as a whole.

[0046] In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit value candidate with any one lower limit value candidate. As an example, consider the following statement: "Parameter B may be A1 or more, A2 or more, or A3 or more. Parameter B may be A4 or less, A5 or less, or A6 or less." In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0047] To clarify the relationship between directions between drawings, several drawings use arrows with common symbols to indicate a first direction D1, a second direction D2, and a third direction D3 as common directions. The tip of the arrow is the first side of each direction. The side opposite the tip of the arrow is the second side of each direction. As shown in FIG. 2, a symbol with an x ​​in a circle indicates an arrow pointing away from the paper in a direction perpendicular to the paper surface of the drawing. As shown in FIG. 4, a symbol with a dot in a circle indicates an arrow pointing toward the paper in a direction perpendicular to the paper surface of the drawing.

[0048] 1 to 20 are diagrams for explaining the present embodiment. Figures 1 to 20 show several specific examples of an anti-glare sheet 10 according to the present embodiment. Figure 1 is a perspective view showing a display device as an example of application of an anti-glare sheet.

[0049] As shown in FIG. 1 , the anti-glare sheet 10 according to this embodiment may be applied to a display device 65. In the example shown in FIG. 1 , the display device 65 includes a display element 66 and the anti-glare sheet 10. The display element 66 has an image forming surface 66a that displays an image. The anti-glare sheet 10 is overlaid on the display element 66. The anti-glare sheet 10 may be bonded to the display element 66 via a bonding layer containing an adhesive, a pressure-sensitive adhesive, or the like. The display element 66 is not particularly limited. Examples of the display element 66 include a liquid crystal display element, an EL display element, a plasma display element, and an electronic paper element. An observer observes an image displayed by the display element 66 through the anti-glare sheet 10.

[0050] The antiglare sheet 10 includes an antiglare layer 30. The antiglare layer 30 includes an uneven surface 31X. The antiglare layer 30 has an antiglare function. The antiglare layer 30 scatters and reflects at least a portion of incident light. The antiglare layer 30 imparts antiglare properties to the antiglare sheet 10. The antiglare properties are a property that suppresses the reflection of lighting and background objects such as people.

[0051] The antiglare properties of the antiglare sheet 10 can prevent the background of the environment in which the antiglare sheet 10 is placed, such as a lighting device, from being reflected on the antiglare sheet. By preventing the background from being reflected, the area behind the antiglare sheet can be clearly observed. In the example shown in FIG. 1, the antiglare sheet 10 is positioned on the image forming surface 66a of the display element 66. In this example, the image displayed by the display element can be prevented from being superimposed with a reflected image. Therefore, the image displayed by the display element can be clearly observed.

[0052] The antiglare sheet 10 will now be described in more detail.

[0053] The antiglare sheet 10 includes a first surface 11 and a second surface 12. The first surface 11 and the second surface 12 face each other in a first direction D1. The first surface 11 faces the opposite side from the second surface 12 in the first direction D1. The first surface 11 may be located on a first side in the first direction D1. The second surface 12 may be located on a second side in the first direction D1. In the example shown in FIG. 1 , the second surface 12 of the antiglare sheet 10 faces an image forming surface 66a of a display element 66.

[0054] 2, the antiglare sheet 10 may include a substrate 20. The substrate 20 and the antiglare layer 30 are located in this order from the second surface 12 to the first surface 11 in the first direction D1.

[0055] The antiglare layer 30 includes a first surface 31 and a second surface 32. The first surface 31 and the second surface 32 face each other in a first direction D1. The first surface 31 is located on a first side in the first direction D1. The second surface 32 is located on a second side in the first direction D1. As shown in FIG. 2 , the first surface 31 may include an uneven surface 31X. The first surface 31 may be formed by the uneven surface 31X. The uneven surface 31X includes a plurality of peaks 36 and a plurality of valleys 37. The peaks 36 form peaks 36a of the uneven surface 31X. The valleys 37 form bottoms 37a of the uneven surface 31X. The peaks 36 and the valleys 37 may exert optical effects, such as refraction and reflection, on incident light. The second surface 32 may be a flat surface.

[0056] The first surface 31 and the uneven surface 31X may face the opposite side to the second surface 12 in the first direction D1. The first surface 31 and the uneven surface 31X may be farther from the second surface 12 in the first direction D1 than the second surface 32. The first surface 31 and the uneven surface 31X may be closer to the first surface 11 in the first direction D1 than the second surface 32.

[0057] The first surface 11 of the anti-glare sheet 10 may include an uneven surface 11X. The first surface 11 may be formed by the first surface 31. The uneven surface 11X of the anti-glare sheet 10 may be formed by the uneven surface 31X of the anti-glare layer 30. The uneven surface 11X of the anti-glare sheet 10 may include unevenness corresponding to the unevenness of the uneven surface 31X of the anti-glare layer 30. The uneven surface 11X may include peaks (convex portions) at positions facing the peaks (convex portions) 36 of the uneven surface 31X in the first direction D1. The uneven surface 11X may include valleys (concave portions) at positions facing the valleys (concave portions) 37 of the uneven surface 31X in the first direction D1. The peaks (convex portions) of the uneven surface 11X may be lower than the peaks (convex portions) 36 of the uneven surface 31X. The recesses of the uneven surface 11X may be shallower than the valleys (recesses) 37 of the uneven surface 31X.

[0058] 2, the uneven surface 31X of the antiglare layer 30 may constitute the first surface 11 of the antiglare sheet 10. The uneven surface 31X of the antiglare layer 30 constitutes the uneven surface 11X of the antiglare sheet 10.

[0059] The anti-glare sheet 10 has anti-glare properties due to the optical action of the uneven surfaces 11X, 31X. The anti-glare sheet 10 can change the traveling direction of incident light due to the uneven surfaces 11X, 31X. The anti-glare sheet 10 may have a light scattering function that scatters incident light due to the uneven surfaces 11X, 31X. The anti-glare sheet 10 may reflect incident light in a direction other than the specular reflection direction due to the uneven surfaces 11X, 31X. The anti-glare sheet 10 may diffusely reflect at least a portion of the incident light due to the uneven surfaces 11X, 31X.

[0060] The antiglare sheet 10 may include other functional layers different from those shown in the drawings. Examples of other functional layers include a low refractive index layer (low reflection layer, antireflection layer), a hard coat layer, an antistatic layer, an ultraviolet absorbing layer, and an adhesive layer.

[0061] In the illustrated example, the first direction D1 is the stacking direction. Each layer 20, 30 included in the antiglare sheet 10 is stacked in the first direction D1. In the illustrated example, the first direction D1 is the thickness direction of the antiglare sheet 10 and each layer 20, 30. Each layer 20, 30 has a normal direction or perpendicular direction parallel to the first direction D1. Each layer 20, 30 extends in a second direction D2 and a third direction D3 that are perpendicular to the first direction D1. In the illustrated example, the second direction D2 and the third direction D3 are perpendicular to each other. The illustrated example is not limiting, and each layer 20, 30 may be curved.

[0062] Each layer included in the antiglare sheet 10 will now be described in more detail.

[0063] The anti-glare layer 30 will now be described. As described above, the anti-glare layer 30 includes an uneven surface 31X. As shown in FIGS. 2 and 3 , the anti-glare layer 30 includes a plurality of unit element portions 35. Each unit element portion 35 forms either a peak portion 36 or a valley portion 37. The unit element portion 35 refers to a peak portion 36 or a valley portion 37 that has a shape defined as characteristic (A1) described below, among the peak portions 36 and valley portions 37 that form the uneven surface 31X. At least some of the peak portions 36 and valley portions 37 that form the uneven surface 31X are unit element portions 35. All of the peak portions 36 may be unit element portions 35. All of the valley portions 37 may be unit element portions 35. The unit element portions 35 are elements that form the uneven surface 31X. The unit element portions 35 may exert optical effects, such as refraction or reflection, on incident light.

[0064] The antiglare layer 30 may include a main body portion 34 that supports a plurality of peaks 36, a plurality of valleys 37, and a plurality of unit element portions 35. The main body portion 34 is also called a land portion. The main body portion 34 may be sheet-shaped. In the illustrated example, the main body portion 34 constitutes the second surface 32. The main body portion 34 is in contact with the substrate 20. The main body portion 34 may be bonded to the substrate 20.

[0065] As shown in Fig. 2, each of the plurality of unit element parts 35 may form a peak 36. The peak 36 is a part that is raised higher than adjacent parts. The peak 36 forms a protruding part on the uneven surface 31X. The peak 36 forms a peak 36a of the uneven surface 31X.

[0066] 3, each of the plurality of unit element portions 35 may define a valley portion 37. The valley portion 37 is a portion that is recessed relative to adjacent portions. The valley portion 37 forms a recessed portion in the uneven surface 31X. The valley portion 37 forms a bottom portion 37a of the uneven surface 31X.

[0067] The plurality of peaks 36, the plurality of valleys 37, and the plurality of unit elements 35 are arranged two-dimensionally. That is, the plurality of peaks 36, the plurality of valleys 37, and the plurality of unit elements 35 are arranged in two or more non-parallel directions along the sheet surface of the antiglare layer 30. The plurality of peaks 36, the plurality of valleys 37, and the plurality of unit elements 35 are dispersed in the plane. The peaks 36, the valleys 37, and the unit elements 35 are dispersed in both the second direction D2 and the third direction D3.

[0068] The multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be regularly arranged in the plane. The multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be irregularly arranged in the plane. Arrangement or arrangement in the plane refers to the arrangement or arrangement on the sheet surface of the anti-glare sheet 10. As an example of an irregular arrangement, the multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be regularly arranged only in a portion. As an example of an irregular arrangement, the multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be arranged at a constant pitch in only one direction and at a non-constant pitch in another direction. The multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be irregularly arranged without any regularity. The multiple peaks 36, the multiple valleys 37, and the multiple unit elements 35 may be arranged at a non-constant pitch in any direction.

[0069] FIG. 4 shows an example of the arrangement of a plurality of peaks 36 or a plurality of valleys 37. Each point in FIG. 4 indicates one peak 36 or valley 37. The points in FIG. 4 indicate the positions of the peaks 36a of the peaks 36. All peaks 36 may be unit element portions 35. Alternatively, the points in FIG. 4 indicate the positions of the bottoms 37a of the valleys 37. All valleys 37 may be unit element portions 35. In this example, 1000 unit elements are arranged within a 500 μm square.

[0070] A plurality of peaks 36 being regularly arranged means that a plurality of peaks 36a are regularly arranged. A plurality of peaks 36 being irregularly arranged means that a plurality of peaks 36a are irregularly arranged. A plurality of valleys 37 being regularly arranged means that a plurality of bottoms 37a are regularly arranged. A plurality of valleys 37 being irregularly arranged means that a plurality of bottoms 37a are irregularly arranged. A plurality of unit element portions 35 being regularly arranged means that a plurality of peaks 36a or a plurality of bottoms 37a formed by the unit element portions 35 are regularly arranged. A plurality of unit element portions 35 being irregularly arranged means that a plurality of peaks 36a or a plurality of bottoms 37a formed by the unit element portions 35 are irregularly arranged.

[0071] Fig. 5 is a perspective view of a unit element portion 35 that constitutes a peak portion 36. Fig. 6A is a cross-sectional view of a unit element portion 35 that constitutes a peak portion 36. Fig. 6B is a cross-sectional view of a unit element portion 35 that constitutes a valley portion 37. Figs. 6A and 6B show a cross-section of a unit element portion 35 taken along a first direction D1, which is the thickness direction.

[0072] 5 and 6A , the peak portion 36 includes an apex 36a. In the unit element portion 35 that constitutes the peak portion 36, the apex 36a is the apex of the unit element portion 35. The apex 36a is the portion of the peak portion 36 and the unit element portion 35 that constitutes the peak portion 36 that is located closest to the first side in the first direction D1. The apex 36a is the portion of the peak portion 36 and the unit element portion 35 that constitutes the peak portion 36 that is farthest from the second surface 32 along the first direction D1.

[0073] 6B , the valley portion 37 includes a bottom portion 37a. In the unit element portion 35 that constitutes the valley portion 37, the bottom portion 37a is the bottom of the unit element portion 35. The bottom portion 37a is the portion of the valley portion 37 and the unit element portion 35 that constitutes the valley portion 37 that is located closest to the second surface 32 in the first direction D1. In the valley portion 37 and the unit element portion 35 that constitutes the valley portion 37, the bottom portion 37a is the portion that is closest to the second surface 32 along the first direction D1.

[0074] As shown in FIGS. 5 to 7 , the unit element portion 35 includes a central portion 38 and a peripheral portion 39. In the unit element portion 35 that forms the peak portion 36, the central portion 38 includes a peak portion 36 a. In the unit element portion 35 that forms the valley portion 37, the central portion 38 includes a bottom portion 37 a. The peripheral portion 39 is connected to the central portion 38. As shown in FIG. 5 , the peripheral portion 39 may surround the entire periphery of the central portion 38. In the example shown in FIG. 5 , the peripheral portion 39 is connected to the periphery of the central portion 38 over the entire length of the periphery. The peripheral portion 39 may also be connected to a portion of the periphery of the central portion 38. One unit element portion 35 may include multiple peripheral portions 39. The multiple peripheral portions 39 may be located apart from each other.

[0075] The anti-glare sheet 10 according to this embodiment has the following A2 (A1) regarding the unit element portion 35. According to feature (A1), an excellent glossiness can be imparted to the anti-glare sheet 10, which has sufficient anti-glare function. That is, according to feature (A1), both the anti-glare property and glossiness of the anti-glare sheet can be improved. According to feature (A1), clouding of the anti-glare sheet 10 can be suppressed, thereby imparting a luxurious feel to the anti-glare sheet 10.

[0076] <Feature (A1)> The cross-sectional profile of each of the plurality of unit element portions 35 is convex upward in the central portion 38 and convex downward in the peripheral portion 39, or is convex downward in the central portion 38 and convex upward in the peripheral portion 39.

[0077] The "cross-sectional outline of the unit element portion 35" in feature (A1) refers to the outline of the unit element portion 35 on the cross section of the anti-glare layer 30. The cross section of the anti-glare layer 30 is a cross section of the anti-glare layer 30 that passes through the peaks 36a of the peaks 36 or the bottoms 37a of the valleys 37 and is taken along the first direction D1, which is the thickness direction.

[0078] The term "convex upward" in feature (A1) means that, with respect to a line segment connecting any two points on the cross-sectional profile, the cross-sectional profile located between the two points is located on the first side in the first direction D1. In other words, "convex upward" means that, with respect to a line segment connecting any two points on the cross-sectional profile, the cross-sectional profile located between the two points moves away from the second surface 32 along the first direction D1. In other words, "convex upward" means that, when the cross-sectional profile is expressed as a function in a coordinate system with the first direction D1 as the y-axis, the slope of the function continues to decrease. In other words, "convex upward" means that, when the cross-sectional profile is expressed as a function in a coordinate system with the first direction D1 as the y-axis, the second derivative of the function is negative.

[0079] The term "downward convex" in feature (A1) means that the cross-sectional profile located between any two points on the cross-sectional profile is located on the second side in the first direction D1 relative to a line segment connecting the two points. In other words, "downward convex" means that the cross-sectional profile located between any two points on the cross-sectional profile is closer to the second surface 32 along the first direction D1 relative to a line segment connecting the two points on the cross-sectional profile. In other words, "downward convex" means that when the cross-sectional profile is expressed as a function in a coordinate system with the first direction D1 as the y-axis, the slope of the function continues to increase. In other words, "downward convex" means that when the cross-sectional profile is expressed as a function in a coordinate system with the first direction D1 as the y-axis, the second derivative of the function is positive.

[0080] When the cross-sectional contour is expressed as a function in coordinates in which the first direction D1 is the y-axis at the position where the central portion 38 and the peripheral portion 39 connect, the value of the second derivative of the function is 0. In other words, the position where the central portion 38 and the peripheral portion 39 connect is an inflection point of the function.

[0081] The cross-sectional contours of the peaks 36 and valleys 37 are obtained by the following (M1) to (M6).

[0082] (M1) The surface shape of the textured surface of the anti-glare layer is obtained using a laser microscope. Measurements using the laser microscope are performed at a total of 262,144 (= 512 x 512) measurement positions, with 512 points arranged in each of two orthogonal arrangement directions at a pitch of 0.140 μm. Measurements using the laser microscope measure the position in the first direction D1 at each measurement position, i.e., the height. A laser microscope "VK-X1000" manufactured by Keyence Corporation can be used as the laser microscope. The test environment is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before the test begins.

[0083] (M2) Two-dimensional noise reduction processing is performed on the acquired height data. A smoothing filter is used for the two-dimensional noise reduction processing. The dimensions and distribution of the smoothing filter are selected to effectively remove measurement noise. That is, the dimensions and distribution of the smoothing filter are selected so that the peaks 36 become wider as they move away from the apexes 36a along the first direction D1. The dimensions and distribution of the smoothing filter are selected so that the valleys 37 become wider as they move away from the bottoms 37a along the first direction D1. The two-dimensional noise reduction processing can reduce the effects of defects, foreign matter, etc. on the anti-glare sheet 10 to be evaluated, as well as other measurement noise, etc.

[0084] (M3) From the acquired height data, the peaks 36a of the peaks 36 or the bottoms 37a of the valleys 37 are extracted. The number of peaks 36a or bottoms 37a to be extracted is set to 10.

[0085] The top 36a and bottom 37a are extracted by the following method: First, height measurements at a total of 25 (=5×5) measurement positions, five points in each of two orthogonal arrangement directions at a pitch of 0.140 μm, are compared.

[0086] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the highest in the first direction D1 (located closest to the first side in the first direction D1), it is evaluated that the apex 36a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the highest in the first direction D1, it is evaluated that the apex 36a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0087] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the lowest in the first direction D1 (located closest to the second side in the first direction D1), it is evaluated that the bottom 37a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the lowest in the first direction D1, it is evaluated that the bottom 37a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0088] The central measurement position of the 25 measurement positions refers to the third measurement position in one arrangement direction of the measurement positions and the third measurement position in the other arrangement direction of the measurement positions, among the 25 measurement positions.

[0089] All combinations of "a total of 25 (=5 × 5) measurement positions, arranged in two consecutive arrays of five points each in two array directions," that can be selected from all measurement positions are evaluated. 258,064 (=508 × 508) measurement positions that are the centers of the 25 measurement positions are selected, and it is determined whether each of the 258,064 measurement positions corresponds to the top 36 a or the bottom 37 a.

[0090] (M4) For each of the extracted peaks 36a or valleys 37a, the cross-sectional profile of a cross section parallel to both the short side direction of the measurement area and the first direction D1, which is the thickness direction of the antiglare layer, is identified based on the surface shape of the uneven surface. It is determined whether the characteristic (A1) is satisfied for the obtained 10 cross-sectional profiles.

[0091] (M5) For each of the ten peaks 36a or valleys 37a extracted in (M3), the cross-sectional profile of a cross section parallel to both the long side direction of the measurement area and the first direction D1, which is the thickness direction of the antiglare layer, is identified based on the surface shape of the uneven surface. It is determined whether the ten cross-sectional profiles obtained satisfy characteristic (A1).

[0092] In (M3) above, the top 36a or bottom 37a is extracted using a device attached to the laser microscope or software attached to the laser microscope. In (M4) and (M5) above, the cross-sectional contour is identified based on the height measurement value at each measurement position using a device attached to the laser microscope or software attached to the laser microscope.

[0093] (M6) In the above (M4) and (M5), the antiglare sheet 10 to be evaluated is determined to have the characteristic (A1) if the characteristic (A1) is satisfied in 11 of the 20 cross-sectional contours relating to the 10 peaks 36 or valleys 37. In this evaluation, the unit element portions 35 having the characteristic (A1) constitute more than half of one of the peaks 36 and valleys 37.

[0094] Instead of the evaluation in (M6) above, the number of cross-sectional contours that satisfy the characteristic (A1) among the 20 cross-sectional contours relating to the 10 peaks 36 or valleys 37 may be 13 or more, 15 or more, 17 or more, 18 or more, 19 or more, or 20.

[0095] Furthermore, in the evaluations (M1) to (M6) above, it is determined whether or not at least one of the 20 cross-sectional contours related to the 10 peaks 36 and the 20 cross-sectional contours related to the 10 valleys 37 satisfies the characteristic (A1). Instead of this evaluation, the characteristic (A1) may be satisfied in 11 of the 20 cross-sectional contours related to the 10 peaks 36, and the characteristic (A1) may be satisfied in 11 of the 20 cross-sectional contours related to the 10 valleys 37.

[0096] In addition to feature (A1), the anti-glare sheet 10 according to the present embodiment further has the following feature (A2). Feature (A2) allows the viewer to clearly observe what is behind the anti-glare sheet 10 while sufficiently suppressing the reflection of the background. When a display device 65 including the anti-glare sheet 10 is observed from the front, the image displayed by the display element 66 can be clearly observed while suppressing the reflection of the background on the anti-glare sheet 10.

[0097] <Feature (A2)> The height of the lowest 5% of the positional distribution of the tops 36a in the first direction D1 is lower than the height of the highest 5% of the positional distribution of the bottoms 37a in the first direction D1.

[0098] The "position distribution of the tops 36a in the first direction D1" is the distribution of the heights of the tops 36a. The "position distribution of the bottoms 37a in the first direction D1" is the distribution of the heights of the bottoms 37a.

[0099] The "height that is 5% from the lowest" means the height that, when the heights of the peaks 36a are sorted in descending order, is the height that is 95% of the total, counting from the highest height. For example, if there are 235 peaks 36a, the height of the 223rd highest peak 36a among all the peaks 36a is rounded down to the nearest integer, and the "height that is 5% from the lowest" is defined as the height.

[0100] The "height that is 5% from the top" means a height that is 5% of the total height counting from the highest when the heights of the bottoms 37a are sorted in descending order. For example, if there are 235 bottoms 37a, the height of the 11th highest bottom 37a among all the bottoms 37a is rounded down to the nearest integer and is set as the "height that is 5% from the top."

[0101] Feature (A2) compares the height of the lowest 5% of the position distribution of the tops 36a in the first direction D1 with the height of the highest 5% of the position distribution of the bottoms 37a in the first direction D1. Therefore, feature (A2) means that the distribution of the tops 36a and the distribution of the bottoms 37a substantially overlap in the first direction D1 after measurement noise and the like have been removed.

[0102] The height that is 5% from the bottom in the position distribution of the top 36a in the first direction D1, and the height that is 5% from the top in the position distribution of the bottom 37a in the first direction D1 are determined by the following (L1) to (L4).

[0103] (L1) The surface profile of the textured surface of the anti-glare layer is obtained using a laser microscope. Measurements using the laser microscope are performed at a total of 262,144 (= 512 x 512) measurement positions, with 512 points arranged in each of two orthogonal arrangement directions at a pitch of 0.140 μm. Measurements using the laser microscope measure the position in the first direction D1 at each measurement position, i.e., the height. A laser microscope "VK-X1000" manufactured by Keyence Corporation can be used as the laser microscope. The test environment is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before the test begins.

[0104] (L2) Two-dimensional noise reduction processing is performed on the acquired height data. A smoothing filter is used for the two-dimensional noise reduction processing. The dimensions and distribution of the smoothing filter are selected to effectively remove measurement noise. That is, the dimensions and distribution of the smoothing filter are selected so that the peaks 36 become wider as they move away from the apexes 36a along the first direction D1. The dimensions and distribution of the smoothing filter are selected so that the valleys 37 become wider as they move away from the bottoms 37a along the first direction D1. The two-dimensional noise reduction processing can reduce the effects of defects, foreign matter, etc. on the anti-glare sheet 10 to be evaluated, as well as other measurement noise, etc.

[0105] (L3) From the acquired height data, the peaks 36a of the peaks 36 and the bottoms 37a of the valleys 37 are extracted. The peaks 36a and bottoms 37a are extracted using the following method: First, height measurements at a total of 25 (=5 x 5) measurement positions, five points in each of two orthogonal arrangement directions at a pitch of 0.140 μm, are compared.

[0106] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the highest in the first direction D1 (located closest to the first side in the first direction D1), it is evaluated that the apex 36a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the highest in the first direction D1, it is evaluated that the apex 36a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0107] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the lowest in the first direction D1 (located closest to the second side in the first direction D1), it is evaluated that the bottom 37a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the lowest in the first direction D1, it is evaluated that the bottom 37a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0108] The central measurement position of the 25 measurement positions refers to the third measurement position in one arrangement direction of the measurement positions and the third measurement position in the other arrangement direction of the measurement positions, among the 25 measurement positions.

[0109] All combinations of "a total of 25 (=5 × 5) measurement positions, arranged in two consecutive arrays of five points each in two array directions," that can be selected from all measurement positions are evaluated. 258,064 (=508 × 508) measurement positions that are the centers of the 25 measurement positions are selected, and it is determined whether each of the 258,064 measurement positions corresponds to the top 36 a or the bottom 37 a.

[0110] (L4) The position measurement value in the first direction D1 of the measurement position corresponding to the extracted peak 36a is treated as the height of the peak 36a. The heights (positions in the first direction D1) of all the extracted peaks 36a are used to obtain the position distribution of the peaks 36a in the first direction D1. Based on the obtained position distribution, the height that is the lowest 5% of the position distribution of the peaks 36a in the first direction D1 is identified.

[0111] The position measurement value in the first direction D1 of the measurement position corresponding to the extracted bottom 37a is treated as the height of the bottom 37a. The position distribution of the bottom 37a in the first direction D1 is obtained from the heights (positions in the first direction D1) of all the extracted bottoms 37a. Based on the obtained position distribution, the height that is 5% from the top in the position distribution of the bottom 37a in the first direction D1 is identified.

[0112] The extraction of the top portion 36a or the bottom portion 37a in (L3) above is performed using a device attached to the laser microscope or software attached to the laser microscope.

[0113] In addition to features (A1) and (A2), the anti-glare sheet 10 according to the present embodiment may have the following feature (B). Feature (B) allows the viewer to clearly observe what is behind the anti-glare sheet 10 when viewed from the front, while sufficiently suppressing reflection of the background. When a display device 65 including the anti-glare sheet 10 is viewed from the front, the viewer can clearly observe an image displayed by the display element 66 while suppressing reflection of the background on the anti-glare sheet 10.

[0114] The "front direction" is the normal direction to the image forming surface 66a. In the illustrated example, the "front direction" coincides with the first direction D1.

[0115] <Feature (B)> One of the peaks 36a and the bottoms 37a is irregularly arranged. The wavelength λ (nm), the height distribution width Dh (nm) of one of the peaks 36a and the bottoms 37a, and the refractive index n of the portion constituting the uneven surface 31X of the antiglare layer 30 satisfy the following two formulas (formula B1 and formula B2): (2π / λ)×(n-1)×Dh<2π Formula B1 (2π / λ)×2×Dh≧2π Formula B2

[0116] The wavelength λ is the wavelength of light incident on the antiglare sheet 10 with the maximum radiant flux (W). The radiant flux (W) of light incident on the antiglare sheet 10 is measured using a spectroradiometer. The radiant flux (W) may be measured using a spectroradiometer "CS-2000A" manufactured by Konica Minolta.

[0117] The height distribution width Dh (nm) of the peaks 36a is an index indicating the size of the range in the first direction D1 in which the peaks 36a are mainly distributed. Specifically, the height distribution width Dh is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the position distribution of the peaks 36a of the mountain portions 36 in the first direction D1.

[0118] The height distribution width Dh (nm) of the bottoms 37a is an index indicating the size of the range in the first direction D1 in which the bottoms 37a are mainly distributed. Specifically, the height distribution width Dh is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the position distribution of the bottoms 37a of the valleys 37 in the first direction D1.

[0119] The "height that is 10% from the top" means a height that is 10% of the total height counting from the highest height when the heights of the tops 36a or bottoms 37a are sorted in descending order. For example, if there are 235 tops 36a or bottoms 37a, the height of the 23rd highest top 36a or bottom 37a among all the tops 36a or all the bottoms 37a is rounded down to the nearest integer, and the "height that is 10% from the top" is defined as the height.

[0120] The "height that is 10% from the lowest" means a height that, when the heights of the tops 36 a or bottoms 37 a are sorted in descending order, is the height that is 90% of the total, counting from the highest height. For example, if there are 235 tops 36 a or bottoms 37 a, the height of the 211th highest top 36 a or bottom 37 a among all the tops 36 a or all the bottoms 37 a is rounded down to the nearest integer, and the "height that is 10% from the lowest" is defined as the height.

[0121] The height distribution width Dh is calculated as the difference between the "height that is 10% from the top" and the "height that is 10% from the bottom." When measuring the height of the top 36a or the bottom 37a, the unit of the height distribution width Dh is the same as the unit of the wavelength λ. The unit of the height distribution width Dh and the unit of the wavelength λ may also be "nm."

[0122] The height distribution width Dh (nm) is determined by the following (N1) to (N4).

[0123] (N1) The surface profile of the textured surface of the antiglare layer is obtained using a laser microscope. Measurements using the laser microscope are performed at a total of 262,144 (= 512 x 512) measurement positions, with 512 points arranged in each of two orthogonal arrangement directions at a pitch of 0.140 μm. Measurements using the laser microscope measure the position in the first direction D1 at each measurement position, i.e., the height. A laser microscope "VK-X1000" manufactured by Keyence Corporation can be used as the laser microscope. The test environment is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before the test begins.

[0124] (N2) Two-dimensional noise reduction processing is performed on the acquired height data. A smoothing filter is used for the two-dimensional noise reduction processing. The dimensions and distribution of the smoothing filter are selected to effectively remove measurement noise. That is, the dimensions and distribution of the smoothing filter are selected so that the peaks 36 become wider as they move away from the apexes 36a along the first direction D1. The dimensions and distribution of the smoothing filter are selected so that the valleys 37 become wider as they move away from the bottoms 37a along the first direction D1. The two-dimensional noise reduction processing can reduce the effects of defects, foreign matter, etc. on the anti-glare sheet 10 to be evaluated, as well as other measurement noise, etc.

[0125] (N3) From the acquired height measurement values, the peaks 36a of the peaks 36 or the bottoms 37a of the valleys 37 are extracted. The peaks 36a and bottoms 37a are extracted in the following manner. First, height measurement values ​​at a total of 25 (=5 x 5) measurement positions, five points in each of two orthogonal arrangement directions at a pitch of 0.140 μm, are compared.

[0126] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the highest in the first direction D1 (located closest to the first side in the first direction D1), it is evaluated that the apex 36a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the highest in the first direction D1, it is evaluated that the apex 36a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0127] If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is the lowest in the first direction D1 (located closest to the second side in the first direction D1), it is evaluated that the bottom 37a is formed at the "measurement position that is the center of the 25 measurement positions." If, among the 25 height measurement values, the height measurement value at the measurement position that is the center of the 25 measurement positions is not the lowest in the first direction D1, it is evaluated that the bottom 37a is not formed at the "measurement position that is the center of the 25 measurement positions."

[0128] The central measurement position of the 25 measurement positions refers to the third measurement position in one arrangement direction of the measurement positions and the third measurement position in the other arrangement direction of the measurement positions, among the 25 measurement positions.

[0129] Evaluation is performed on all combinations of "a total of 25 (=5 x 5) measurement positions, with five points arranged consecutively in each of the two arrangement directions," which can be selected from all measurement positions. 258,064 (=508 x 508) measurement positions are selected as the center of the 25 measurement positions, and it is determined whether each of the 258,064 measurement values ​​corresponds to the top 36 a or the bottom 37 a.

[0130] (N4) The position measurement value in the first direction D1 of the measurement position corresponding to the extracted peak 36 a or bottom 37 a is treated as the height of the peak 36 a or bottom 37 a. The heights (positions in the first direction D1) of the extracted peaks 36 a or bottoms 37 a are listed. The height distribution width Dh (nm) is calculated from the listed height data of the peaks 36 a or bottoms 37 a.

[0131] In the above (N3), the extraction and listing of the top portion 36a or the bottom portion 37a is performed using a device attached to the laser microscope or software attached to the laser microscope.

[0132] The refractive index n of the portion constituting the uneven surface of the antiglare layer is measured in accordance with Method A of JIS K7142:2014. The light used for the measurement is D-line (wavelength 589 nm). An Abbe refractometer is used for the measurement.

[0133] Feature (B) requires that one of the tops 36 a and the bottoms 37 a be irregularly arranged, and that the height distribution width Dh (nm) of one of the tops 36 a and the bottoms 37 a satisfy formulas B1 and B2. However, without being limited to this example, it is also possible that both the tops 36 a and the bottoms 37 a are irregularly arranged, and that the height distribution width Dh (nm) of the tops 36 a satisfy formulas B1 and B2, and that the height distribution width Dh (nm) of the bottoms 37 a also satisfy formulas B1 and B2.

[0134] In addition to features (A1) and (A2), the anti-glare sheet 10 according to the present embodiment may have the following feature (C). Feature (C) allows the back of the anti-glare sheet 10 to be clearly observed from the front while sufficiently suppressing reflections. Therefore, when a display device 65 including the anti-glare sheet 10 is observed from the front, the image displayed by the display element 66 can be clearly observed while suppressing reflections of the background on the anti-glare sheet 10.

[0135] <Feature (C)> One of the apexes 36a and the bottoms 37a is arranged irregularly. The height distribution width Dh (nm) of one of the apexes 36a and the bottoms 37a and the refractive index n of the portion constituting the uneven surface 31X of the antiglare layer 30 satisfy the following two formulas (Formula C1 and Formula C2): (2π / 550)×(n-1)×Dh<2π (Formula C1) (2π / 550)×2×Dh≧2π

[0136] Feature (C) sets the wavelength λ in formulas B1 and B2 defined in feature (B) to 550 nm.

[0137] The display element 66 to which the antiglare sheet 10 is applied typically emits red, green, and blue light. The central wavelength of the light emitted from the display element 66 is approximately 550 nm. According to feature (C), an image displayed by light with a wavelength of 550 nm can be clearly observed.

[0138] The reflected image of the background is displayed using visible light. The central wavelength of the visible light that forms the reflected image is approximately 550 nm. According to feature (C), the reflection of the background on the antiglare sheet 10 observed using light with a wavelength of 550 nm can be suppressed.

[0139] As described above, according to feature (C), when observed from the front, the back of the antiglare sheet 10 can be clearly observed while sufficiently suppressing the reflection of the background. When the display device 65 including the antiglare sheet 10 is observed from the front, the image displayed by the display element 66 can be clearly observed while suppressing the reflection of the background on the antiglare sheet 10.

[0140] Feature (C) requires that one of the tops 36 a and the bottoms 37 a be irregularly arranged, and that the height distribution width Dh (nm) of one of the tops 36 a and the bottoms 37 a satisfy formulas C1 and C2. However, without being limited to this example, it is also possible that both the tops 36 a and the bottoms 37 a are irregularly arranged, and that the height distribution width Dh (nm) of the tops 36 a and the height distribution width Dh (nm) of the bottoms 37 a satisfy formulas C1 and C2.

[0141] The antiglare sheet 10 according to this embodiment may have the following feature (D) in addition to feature (C).

[0142] <Characteristic D> In addition to characteristic (C), the following four equations are also satisfied: (2π / 450)×(n-1)×Dh<2π ...Equation D1 (2π / 450)×2×Dh≧2π ...Equation D2 (2π / 680)×(n-1)×Dh<2π ...Equation D3 (2π / 680)×2×Dh≧2π ...Equation D4

[0143] When characteristic (C) is satisfied, the antiglare sheet 10 acts on light with a wavelength of 550 nm, which is the central wavelength of visible light that forms images and glare images, allowing images to be clearly observed while suppressing reflection of the background onto the antiglare sheet 10. When characteristic (D) is satisfied, the antiglare sheet 10 effectively acts on light with wavelengths of 450 nm, 550 nm, and 680 nm. That is, characteristic (D) allows images formed by light over substantially the entire visible light wavelength range to be clearly observed while suppressing reflection onto the antiglare sheet 10 caused by light over substantially the entire visible light wavelength range.

[0144] As described above, according to feature (D), when observed from the front, the area behind the antiglare sheet 10 can be clearly observed while sufficiently suppressing the reflection of the background. When a display device 65 including the antiglare sheet 10 is observed from the front, the image displayed by the display element 66 can be clearly observed while suppressing the reflection of the background on the antiglare sheet 10.

[0145] Feature (D) requires that the height distribution width Dh (nm) of one of the top 36a and the bottom 37a satisfies formulas D1 to D4. However, this example is not limiting, and the height distribution width Dh (nm) of the top 36a may satisfy formulas D1 to D4, and the height distribution width Dh (nm) of the bottom 37a may also satisfy formulas D1 to D4.

[0146] The antiglare sheet 10 according to the present embodiment may further have a feature (E) in addition to any one of the above features (B) to (D).

[0147] <Feature E> Furthermore, the upper limit in the following formulas in features (B) to (D) is set to "π". (2π / λ)×(n-1)×Dh<2π ... Formula B1 (2π / 550)×(n-1)×Dh<2π ... Formula C1 (2π / 450)×(n-1)×Dh<2π ... Formula D1 (2π / 680)×(n-1)×Dh<2π ... Formula D3

[0148] That is, as characteristic (E), the following formulas are further satisfied in each of characteristics (B) to (D): (2π / λ)×(n-1)×Dh≦π ... formula B1X (2π / 550)×(n-1)×Dh≦π ... formula C1X (2π / 450)×(n-1)×Dh≦π ... formula D1X (2π / 680)×(n-1)×Dh≦π ... formula D3X

[0149] When the formulae B1X, C1X, D1X, and D3X are satisfied, the image formed by the display element 66 can be observed more clearly through the antiglare sheet 10.

[0150] Feature (E) requires that the height distribution width Dh (nm) of one of the top portion 36a and the bottom portion 37a satisfy the formulas B1X, C1X, D1X, and D3X. However, without being limited to this example, the height distribution width Dh (nm) of the top portion 36a may satisfy the formulas B1X, C1X, D1X, and D3X, and the height distribution width Dh (nm) of the bottom portion 37a may satisfy the formulas B1X, C1X, D1X, and D3X.

[0151] The above-described features (A1), (A2), and (B) to (E) can impart excellent optical properties to the antiglare sheet 10. Feature (A1) can improve both the antiglare properties and the glossy appearance. Features (A2), and (B) to (E) can improve both the antiglare properties and the transmitted light clarity.

[0152] <Transmission Haze> A lower limit may be set for the transmission haze of the antiglare sheet 10. Setting a lower limit for the transmission haze can impart antiglare properties to the antiglare sheet 10. In particular, with an antiglare sheet 10 having one or more of the features (A1), (A2), and (B) to (E), the transmission haze can be made sufficiently large due to the scattering function caused by the uneven surfaces 11X and 31X. The transmission haze of the antiglare sheet 10 may be 3.0% or more, 4.9% or more, 10% or more, 12% or more, 15% or more, or 20% or more.

[0153] An upper limit may be set for the transmission haze. By setting an upper limit for the transmission haze, the back of the antiglare sheet 10 can be clearly observed. In particular, with an antiglare sheet 10 having one or more of the features (B) to (E), the transmission haze can be made sufficiently small, allowing the back of the antiglare sheet 10 to be very clearly observed from the front. The transmission haze of the antiglare sheet 10 may be 75% or less, 60% or less, 53% or less, 40% or less, 30% or less, or 24% or less.

[0154] A light source simulating the spectrum of D65 standard light (hereinafter referred to as the D65 light source) is used to measure the transmission haze of the antiglare sheet 10. Before measuring the transmission haze, the D65 light source is turned on for 15 minutes to stabilize the output of the D65 light source. The incident angle on the sample when measuring the transmission haze is 0°. The incident surface when measuring the transmission haze of the antiglare sheet 10 is the second surface 12 of the antiglare sheet 10. The test environment when measuring the transmission haze is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before starting the test. Other measurement conditions when measuring the transmission haze are in accordance with JIS K7136:2000.

[0155] The incident angle is the angle (°) between the normal direction of the incident object and the incident direction, and is an angle between 0° and 90°.

[0156] The transmission haze is the arithmetic mean value of five measurements taken at five measurement positions on the antiglare sheet to be evaluated, the five measurement positions being spaced at least 10 mm apart from each other.

[0157] <Image clarity> A lower limit may be set for the image clarity of the anti-glare sheet 10 measured by a transmission method. Setting a lower limit for the image clarity allows the area behind the anti-glare sheet 10 to be clearly observed. In particular, with an anti-glare sheet 10 having one or more of features (B) to (E), the image clarity is sufficiently increased, allowing the area behind the anti-glare sheet 10 to be very clearly observed from the front. The image clarity of the anti-glare sheet 10 measured by a transmission method may be 5.0% or more, 5.6% or more, 10% or more, 16% or more, 25% or more, 40% or more, or 43% or more.

[0158] There is no particular upper limit set for the image clarity of the antiglare sheet 10 measured by a transmission method. However, as the image clarity increases, the antiglare properties tend to decrease. The image clarity of the antiglare sheet 10 measured by a transmission method may be 100% or less, 84% or less, 80% or less, 70% or less, or 60% or less.

[0159] The image clarity measured by the transmission method is calculated from the measured amount of light transmitted through the measurement sample. The amount of light transmitted through the measurement sample is measured after passing through an optical comb. The optical comb includes a transmitting portion and a light-blocking portion. The transmitting portion and the light-blocking portion are arranged in the arrangement direction. The transmitting portion and the light-blocking portion extend in an elongated shape in a direction perpendicular to the arrangement direction. An optical comb with a width of 0.5 mm is used to measure the image clarity. The "width" of the optical comb refers to the width of the light-blocking portion along the arrangement direction.

[0160] The amount of light transmitted through the measurement sample is measured while moving the optical comb in the arrangement direction. The maximum light amount M and minimum light amount m are identified from the measured values. Image clarity C is expressed by the following formula. Image clarity is the ratio of the difference between the maximum light amount M and the minimum light amount m to the sum of the maximum light amount M and the minimum light amount m. The ratio, which is image clarity, is expressed as a percentage. The unit of image clarity is "%". C(k) = {(M-m) / (M+m)} x 100 [%]

[0161] Before measuring image clarity, the light source is turned on for 15 minutes to stabilize the light source output. The measurement environment for image clarity measurement is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The measurement sample is placed in the measurement environment for 16 hours before starting the measurement.

[0162] The image clarity is the arithmetic mean value of five measurements taken at five measurement positions on the antiglare sheet to be evaluated, the five measurement positions being at least 10 mm apart from each other.

[0163] Other conditions for measuring image clarity are in accordance with JIS K7374:2007.

[0164] <Specular Gloss> A lower limit may be set for the specular gloss Gs(60) on the first surface 11 of the anti-glare sheet 10. By setting a lower limit for the specular gloss, a glossy appearance can be imparted to the first surface 11 of the anti-glare sheet 10. The glossy anti-glare sheet 10 has a luxurious feel, and the commercial value of an article to which the anti-glare sheet 10 is applied, such as a display device 65, can be improved. In particular, according to feature (A1), the specular gloss can be increased, and an excellent glossy appearance can be imparted to the anti-glare sheet 10. The specular gloss Gs(60) on the first surface 11 may be 8.0% or more, 9.3% or more, 15% or more, 19% or more, 25% or more, 30% or more, 35% or more, or 39% or more.

[0165] There is no particular upper limit set for the specular glossiness Gs(60) on the first surface 11 of the antiglare sheet 10. However, as the specular glossiness Gs(60) increases, the antiglare properties tend to decrease. The specular glossiness Gs(60) on the first surface 11 of the antiglare sheet 10 may be 80% or less, 78% or less, 70% or less, 60% or less, or 50% or less.

[0166] The specular gloss Gs(60) on the first surface 11 is a value measured in accordance with JIS Z 8741:1997, except that the angle of incidence is set to 60°. The incident surface when measuring the specular gloss Gs(60) is the first surface 11. The measurement environment when measuring the specular gloss is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample to be measured is placed in the measurement environment for 16 hours before starting the measurement. Before measuring the specular gloss, the light source of the measurement device is turned on for 15 minutes to stabilize the light source output.

[0167] When measuring specular gloss, a black plate is attached to the back surface of the evaluation sample to be measured, opposite the incident surface, via an optically transparent adhesive sheet. The optically transparent adhesive sheet is "Panaclean PD-S1" manufactured by Panac Corporation. The black plate is "Comoglass DFA2CG 502K (black) series" manufactured by Kuraray Co., Ltd.

[0168] The specular gloss Gs(60) is the arithmetic mean value of five measured values. The five measured values ​​are measured at five measurement positions on the antiglare sheet to be evaluated. The five measurement positions are located at least 10 mm apart from each other.

[0169] Other conditions for measuring the specular gloss Gs(60) are in accordance with JIS Z 8741:1997.

[0170] <Reflected Zeroth-Order Light Intensity at 0° Incidence> An upper limit may be set for the reflected zeroth-order light intensity at 0° incidence on the first surface 11 of the antiglare sheet 10. Hereinafter, the "reflected zeroth-order light intensity at 0° incidence on the first surface 11 of the antiglare sheet 10" will also be simply referred to as the "reflected zeroth-order light intensity."

[0171] Setting an upper limit to the reflected zeroth-order light intensity can impart antiglare properties to the antiglare sheet 10. In particular, with the antiglare sheet 10 having one or more of the features (A1), (A2), and (B) to (E), the reflected zeroth-order light intensity can be sufficiently reduced by scattered reflection at the uneven surfaces 11X and 31X. The reflected zeroth-order light intensity at the first surface 11 of the antiglare sheet 10 may be 20% or less, 17% or less, 15% or less, 10% or less, 5.0% or less, 3.0% or less, or 1.0% or less.

[0172] There is no particular lower limit set for the reflected zeroth-order light intensity on the first surface 11 of the antiglare sheet 10. However, if the reflected zeroth-order light intensity is small, the antiglare sheet 10 tends to lose its glossiness and become cloudy. If the reflected zeroth-order light intensity is small, it tends to become difficult to clearly observe what is behind the antiglare sheet 10. The 0° reflected zeroth-order light intensity on the first surface 11 of the antiglare sheet 10 may be greater than 0, may be 0% or more, may be 0.10% or more, or may be 0.30% or more.

[0173] The reflected zeroth-order light intensity is the ratio of the radiant flux (W) of the reflected zeroth-order light to the radiant flux (W) of the incident light. The reflected zeroth-order light intensity is expressed as a percentage. The unit of the reflected zeroth-order light intensity is "%". The light source is a HeNe laser light source that emits laser light with a wavelength of 543.5 nm and a beam diameter of 1 mm. The angle of incidence on the evaluation sample is 0°. The incident surface on the antiglare sheet 10, which is the evaluation sample, is the first surface 11.

[0174] When measuring the reflected zero-order light intensity, a black plate is attached to the back surface of the evaluation sample to be measured, opposite the incident surface, via an optically transparent adhesive sheet. The optically transparent adhesive sheet is "Panaclean PD-S1" manufactured by Panac Corporation. The black plate is "Comoglass DFA2CG 502K (black) series" manufactured by Kuraray Co., Ltd.

[0175] The light receiver, which measures the radiant flux (W) of the reflected light, is placed behind the light shielding plate with a pinhole formed in it. The light receiver measures the radiant flux (W) of the laser light that passes through the pinhole. The light shielding plate is placed so that the pinhole is located on the optical path of the specularly reflected light from the evaluation sample. The diameter of the pinhole is 3 mm. The distance from the light shielding plate to the reflection position on the measurement sample is 200 mm.

[0176] Before measuring the reflected zero-order light intensity, the light source is turned on for 15 minutes to stabilize the light source output. The measurement environment for measuring the reflected zero-order light intensity is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The measurement sample is placed in the measurement environment for 16 hours before starting the measurement.

[0177] The reflected zero-order light intensity is the arithmetic mean value of five measured values. The five measured values ​​are measured at five measurement positions on the antiglare sheet to be evaluated. The five measurement positions are located at least 10 mm apart from each other.

[0178] <Total Light Transmittance> The total light transmittance of the antiglare sheet 10 may be 50% or more, 70% or more, 80% or more, or 90% or more. The total light transmittance of the antiglare sheet 10 does not have a particular upper limit. The total light transmittance of the antiglare sheet 10 may be 100% or less, or may be less than 100%.

[0179] A D65 light source is used to measure the total light transmittance. Before measuring the total light transmittance, the D65 light source is turned on for 15 minutes to stabilize the output of the D65 light source. The angle of incidence on the measurement sample when measuring the total light transmittance is 0°. The incident surface when measuring the total light transmittance of the antiglare sheet 10 is the second surface 12 of the antiglare sheet 10. The test environment when measuring the total light transmittance is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The measurement sample is placed in the test environment for 16 hours before starting the test. Other measurement conditions when measuring the total light transmittance are in accordance with JIS K7361-1:1997.

[0180] The total light transmittance is the arithmetic mean value of five measured values. The five measured values ​​are measured at five measurement positions on the antiglare sheet to be evaluated. The five measurement positions are located at least 10 mm apart from each other.

[0181] The peaks 36, valleys 37, and unit element portions 35 of the antiglare layer 30 may have the following dimensions.

[0182] The length D35 (see FIG. 2 ) of the peaks 36 and the unit element parts 35 constituting the peaks 36 along the first direction D1 may be 0 μm or more and 0.90 μm or less, 0.20 μm or more and 1.1 μm or less, 0 μm or more and 1.6 μm or less, or 0.30 μm or more and 1.9 μm or less. The length D35 of the peaks 36 and the unit element parts 35 constituting the peaks 36 along the first direction D1 corresponds to the height.

[0183] The length D35 (see FIG. 3 ) of the valley portion 37 and the unit element portion 35 constituting the valley portion 37 along the first direction D1 may be 0 μm or more and 0.90 μm or less, 0.20 μm or more and 1.1 μm or less, 0 μm or more and 1.6 μm or less, or 0.30 μm or more and 1.9 μm or less. The length D35 of the valley portion 37 and the unit element portion 35 constituting the valley portion 37 along the first direction D1 corresponds to the depth (height).

[0184] The length D34 of the main body 34 along the first direction D1 (see FIGS. 2 and 3) may be 0 μm or more and 5.0 μm or less, or 0 μm or more and 100 μm or less. The length D34 of the main body 34 along the first direction D1 corresponds to the thickness of the main body 34.

[0185] The length W35 ( FIG. 5 ) of the peaks 36, the valleys 37, and the unit element portions 35 along a direction perpendicular to the first direction D1 may be 1.0 μm or more and 10 μm or less, 2.0 μm or more and 20 μm or less, 5.0 μm or more and 50 μm or less, or 10 μm or more and 100 μm or less. The length W35 of the peaks 36, the valleys 37, and the unit element portions 35 along a direction perpendicular to the first direction D1 corresponds to the width.

[0186] The maximum inclination angle θx of the peaks 36, valleys 37, and unit element portions 35 may be 2.0° or more and 10° or less, or 5.0° or more and 25° or less. The maximum inclination angle θx is the smaller of the angles that the cross-sectional contours of the peaks 36, valleys 37, and unit element portions 35 form with a plane perpendicular to the first direction D1. The maximum inclination angle θx is a value that is 0° or more and 90° or less. The cross-sectional contours of the peaks 36, valleys 37, and unit element portions 35 are specified by the above-mentioned (M1) to (M5).

[0187] The refractive index n of the portion that constitutes the uneven surface of the antiglare layer may be 1.40 or more and 1.90 or less, or 1.40 or more and 1.60 or less.

[0188] The antiglare layer 30 may be made of the materials described below.

[0189] There are no particular limitations on the material used for the antiglare layer 30. The antiglare layer 30 may be made of a resin that is easy to process. If the resin is easy to process, the antiglare layer 30 can be stably given the above-mentioned shape and dimensions.

[0190] The anti-glare layer 30 may contain a cured resin. The cured resin is a cured product of a curable resin composition. The curable resin composition may be a thermosetting resin composition. The curable resin composition may be an ionizing radiation curable resin composition. The anti-glare layer 30 may contain at least one of a cured product of a thermosetting resin composition and a cured product of an ionizing radiation curable resin composition. The cured resin imparts high strength and high hardness to the anti-glare layer 30.

[0191] The thermosetting resin composition contains a thermosetting resin. The thermosetting resin composition is cured by heating. Examples of the thermosetting resin include acrylic resin, urethane resin, phenolic resin, urea melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin. The thermosetting resin composition may contain a curing agent.

[0192] The ionizing radiation-curable resin composition contains a compound having an ionizing radiation-curable functional group. Hereinafter, the compound having an ionizing radiation-curable functional group is also referred to as an "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 compound may contain an ethylenically unsaturated bond group. The ionizing radiation-curable compound may contain two or more ethylenically unsaturated bond groups. The ionizing radiation-curable compound may be a polyfunctional (meth)acrylate compound containing two or more ethylenically unsaturated bond groups. The polyfunctional (meth)acrylate compound may contain either a monomer or an oligomer. The ionizing radiation may be electromagnetic waves or charged particle beams. The ionizing radiation has an energy quantum capable of polymerizing or crosslinking molecules. Examples of ionizing radiation include ultraviolet (UV) rays, electron beams (EB), X-rays, gamma rays, alpha rays, and ion rays.

[0193] Among the 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, etc. Examples of trifunctional or higher functional (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, etc. The (meth)acrylate monomer may have a partially modified molecular skeleton. The (meth)acrylate monomer may have a part of its molecular skeleton modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, or the like.

[0194] Examples of polyfunctional (meth)acrylate oligomers include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylate can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate. The epoxy (meth)acrylate may be a (meth)acrylate obtained by reacting a trifunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with (meth)acrylic acid. The epoxy (meth)acrylate may be a (meth)acrylate obtained by reacting a difunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a polybasic acid and (meth)acrylic acid. The epoxy (meth)acrylate may be a (meth)acrylate obtained by reacting a difunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a phenol and (meth)acrylic acid.

[0195] One type of ionizing radiation curable compound may be used alone, or two or more types of ionizing radiation curable compounds may be used in combination.

[0196] The antiglare layer 30 may contain a thermoplastic resin. Examples of the thermoplastic resin include polystyrene-based resins, polyolefin-based resins, ABS resins (including heat-resistant ABS resins), AS resins, AN resins, polyphenylene oxide-based resins, polycarbonate-based resins, polyacetal-based resins, acrylic-based resins, polyethylene terephthalate-based resins, polybutylene terephthalate-based resins, polysulfone-based resins, and polyphenylene sulfide-based resins.

[0197] The antiglare layer 30 having the above configuration may be manufactured as follows.

[0198] A coating liquid containing a curable resin composition is prepared. The coating liquid is applied to a substrate to form a coating film of the coating liquid on the substrate. The surface of the coating film is brought into contact with the mold surface of a mold, and the recesses on the mold surface are filled with the coating liquid. The mold surface has a shape complementary to the uneven surface 31X to be produced. The curable resin composition of the coating liquid located between the substrate and the mold is cured. The antiglare layer 30 is obtained as a cured resin product formed by curing the curable resin composition. The obtained antiglare layer 30 is bonded to the substrate 20. In the produced antiglare layer 30, the peaks 36, valleys 37, unit element portions 35, and main body portion 34 are made of the same material. The peaks 36, valleys 37, unit element portions 35, and main body portion 34 are molded integrally without any seams.

[0199] In this manufacturing method, the curable resin composition may be an ionizing radiation curable composition. The curable resin composition may be an ultraviolet curable resin composition. The ultraviolet curable resin composition can be cured by ultraviolet light that has passed through the substrate. The coating liquid may contain a solvent.

[0200] Alternatively, the antiglare layer 30 may be produced by embossing a resin layer containing a thermoplastic resin. In the produced antiglare layer 30, the peaks 36, valleys 37, and unit element portions 35 are made of the same material as the main body portion 34. In this production method, the peaks 36, valleys 37, and unit element portions 35 are also molded seamlessly as a single unit with the main body portion 34. The resin layer containing a thermoplastic resin may be formed by applying a coating liquid containing a thermoplastic resin onto the substrate 20 and drying the resulting coating film on the substrate. In this case, an antiglare layer 30 bonded to the substrate 20 is obtained.

[0201] The coating liquid containing a thermoplastic resin may or may not contain a solvent. By using a solvent, the leveling of the coating film on the substrate can be improved. By using a solvent, the adhesion between the substrate and the antiglare layer 30 can be improved. By not using a solvent, VOCs emitted during production can be reduced. By not using a solvent, the drying step can be omitted, and the amount of energy required for production can be significantly reduced.

[0202] As another method, the anti-glare layer 30 may be produced by embossing a resin layer containing a thermosetting resin. The resin layer may be a layer obtained by semi-curing a coating film containing a thermosetting resin. The coating film of the thermosetting resin may be formed by applying a coating liquid containing the thermosetting resin onto the substrate 20. In this case, the anti-glare layer 30 bonded to the substrate 20 is obtained. The resin layer may be cured by heating the resin layer after and / or during the embossing process. In this manufacturing method, the peaks 36, the valleys 37, the unit element portions 35, and the main body portion 34 are also molded seamlessly and integrally.

[0203] In any of the manufacturing methods described above, the uneven surface 31X of the antiglare layer 30 is formed by transferring the uneven surface using a mold. By creating the uneven surface 31X by molding, it is possible to impart a desired shape to the uneven surface 31X with a high degree of freedom. For example, it is possible to stably produce an antiglare layer 30 having the above-mentioned characteristics (A1), (A2), and (B) to (E).

[0204] In conventional antiglare sheets, the textured surface of the antiglare layer has been formed by incorporating particles or by blasting. Conventional antiglare sheets have been able to adjust any one of haze, image clarity, and specular gloss. However, conventional antiglare sheets have not been able to adjust the shape of the textured surface with a high degree of freedom. Furthermore, there has been no technical concept of achieving desired optical properties by controlling the shape of the peaks 36, valleys 37, or textured surface.

[0205] Against the background described above, according to the present embodiment, the features (A1), (A2), and (B) to (E) can impart contradictory optical properties, such as antiglare properties and transmission clarity, or antiglare properties and specular gloss, to the antiglare layer 30. In light of the background described above, the effects obtained by one or more of the features (A1), (A2), and (B) to (E) are remarkable effects that go beyond the range predicted from the state of the art.

[0206] However, in the above-described method for producing an antiglare sheet, the coating liquid used to produce the antiglare layer 30 may or may not contain particles. The use of particles makes it easier to reduce the internal haze in the antiglare layer 30 and also reduces speckles caused by particles. The use of particles can improve the surface hardness and the antifouling properties.

[0207] The manufacturing method of the antiglare sheet described above includes a step of applying a coating liquid containing a resin that constitutes the antiglare layer 30 onto a substrate. According to the manufacturing method described above, a long sheet product 5 including a large number of antiglare sheets 10 can be manufactured, as shown in FIG. 8 . The long sheet product 5 is cut to a predetermined size to obtain the antiglare sheet 10. According to this example, antiglare sheets 10 having various dimensions can be obtained from the long sheet product 5 in accordance with needs. Therefore, antiglare sheets 10 having various dimensions can be provided in a timely manner. As shown in FIG. 8 , handling the sheet product 5 as a roll 7 wound around a winding core about a winding axis RA improves the handleability of the sheet product 5.

[0208] The manufacturing method of the antiglare sheet described above includes a step of forming the uneven surface 31X. The manufacturing method of the antiglare sheet may include a step of determining the arrangement of the plurality of peaks 36 or valleys 37 before the step of forming the uneven surface 31X. FIG. 16 shows an example of the arrangement of the plurality of peaks 36 or valleys 37 determined in this step. As in FIG. 4 , each point in FIG. 16 indicates the peak 36 a of one peak 36 or the bottom 37 a of one valley 37. In the example shown in FIG. 16 , the plurality of peaks 36 or valleys 37 are arranged irregularly.

[0209] The step of determining the arrangement of the plurality of peaks 36 or the plurality of valleys 37 may include a step of provisionally determining the arrangement of the plurality of peaks 36 or the plurality of valleys 37 and a step of adjusting the provisionally determined arrangement of the plurality of peaks 36 or the plurality of valleys 37. In the step of provisionally determining the arrangement, the peaks 36 or the valleys 37 may be arranged irregularly. In the step of adjusting the arrangement, the arrangement of the peaks 36 or the valleys 37 may be made uniform. In the step of adjusting the arrangement, the in-plane variation in density of the peaks 36 or the valleys 37 may be made equal to or less than a predetermined value. The arrangement of the peaks 36 or the valleys 37 shown in FIG. 16 has a large variation in density of the peaks 36 or the valleys 37. When the arrangement of the peaks 36 or the valleys 37 shown in FIG. 16 is provisionally determined, the density variation may be set equal to or greater than a predetermined value to make the density uniform. As an example, the arrangement of the peaks 36 or valleys 37 shown in FIG. 16 may be modified to the arrangement of the peaks 36 or valleys 37 shown in FIG.

[0210] The method for manufacturing the antiglare sheet described above includes a step of shaping the uneven surface 31X. The method for manufacturing the antiglare sheet may include a step of determining the shape of the uneven surface 31X before the step of shaping the uneven surface 31X.

[0211] In the process of determining the shape of the uneven surface 31X, the cross-sectional contours of the plurality of peaks 36 or the plurality of valleys 37 may be provisionally determined. In this process, the provisionally determined cross-sectional contours may further be smoothed at the connection points between adjacent pairs of the plurality of peaks 36 or the plurality of valleys 37. That is, as shown in FIG. 17 as an example, the shape may be adjusted so that two adjacent peaks 36 (unit element portions 35) are smoothly connected. In the example shown in FIG. 17, the peripheral portions 39 of the two adjacent peaks 36 (unit element portions 35) are modified as indicated by the dotted lines.

[0212] For smoothing, a smoothing filter process that is common in image processing may be used. The size and distribution of the smoothing filter are appropriately selected so as to provide a glossy appearance while ensuring anti-glare properties.

[0213] Smoothing can widen the area with a small inclination angle. As will be described with reference to Figures 6A and 6B, by ensuring a wide area with a small inclination angle, most of the external light incident from the front direction can be scattered and reflected in directions within a narrow angle range AR10. By narrowing the angle range within which the area where light is mainly scattered and reflected is, it is possible to impart an excellent glossiness to the antiglare sheet 10 while ensuring the necessary antiglare properties.

[0214] In the process of determining the shape of the uneven surface 31X, it may be confirmed whether the characteristic (A1) is satisfied. That is, in the process of determining the shape of the uneven surface 31X, it may be confirmed that the cross-sectional profile of the peaks 36 or valleys 37 is convex upward in the central portion 38 and convex downward in the peripheral portion 39 connected to the central portion, or is convex downward in the central portion 38 and convex upward in the peripheral portion 39. In this way, the peaks 36 or valleys 37 are constituted by unit element portions 35 having the characteristic (A1).

[0215] The method for manufacturing the antiglare sheet described above includes a step of forming the uneven surface 31X. The method for manufacturing the antiglare sheet may include a step of determining the height distribution width Dh before the step of forming the uneven surface 31X.

[0216] In the step of determining the height distribution width Dh, it may be confirmed that the following two formulas using the refractive index n of the portion constituting the uneven surface 31X of the anti-glare layer 30 are satisfied. The following two formulas correspond to formula C1 and formula C2 in the above-mentioned feature (C): (2π / 550)×(n-1)×Dh<2π ... formula C1 (2π / 550)×2×Dh≧2π ... formula C2

[0217] In the process of determining the height distribution width Dh, it may be confirmed that the following two formulas are satisfied, using the wavelength λ (nm) of light incident on the antiglare sheet 30 with the maximum radiant flux (W) and the refractive index n of the portion constituting the uneven surface 31X of the antiglare layer 30. The following two formulas correspond to formula B1 and formula B2 in the above-mentioned feature (B): (2π / λ)×(n-1)×Dh<2π ... formula B1 (2π / λ)×2×Dh≧2π ... formula B1

[0218] After the above-described manufacturing of the anti-glare sheet is completed, the manufactured anti-glare sheet 10 may be selected. The manufacturing method of the anti-glare sheet may include a step of manufacturing the anti-glare sheet and a step of selecting the anti-glare sheet. By selecting the anti-glare sheet, it is possible to stably supply the anti-glare sheet 10 having both improved anti-glare properties and glossiness. By selecting the anti-glare sheet, it is possible to stably supply the anti-glare sheet 10 having both improved anti-glare properties and transmission clarity.

[0219] The antiglare sheet selection method or selection step may include a step of acquiring cross-sectional contours of at least some of the unit element portions 35, and a step of confirming the cross-sectional contours. In the step of confirming the cross-sectional contours, it may be confirmed that the cross-sectional contour is convex upward in the central portion 38 and convex downward in the peripheral portion 39 connected to the central portion 38, or that the cross-sectional contour is convex downward in the central portion 38 and convex upward in the peripheral portion 39.

[0220] The method or step of selecting an antiglare sheet may include a step of obtaining a positional distribution of the tops 36a in the first direction D1 and a positional distribution of the bottoms 37a in the first direction D1. Furthermore, the method or step of selecting an antiglare sheet may include a step of confirming that the height of the lowest 5% of the tops 36a in the positional distribution of the bottoms 37a in the first direction D1 is lower than the height of the highest 5% of the bottoms 37a in the first direction D1.

[0221] The method or step of selecting an antiglare sheet may include a step of obtaining the height distribution width Dh (nm) of one of the plurality of peaks 36a and the plurality of bottoms 37a, and a step of confirming that the following two formulas using the refractive index n of the portion that constitutes the uneven surface 31X of the antiglare layer 30 are satisfied. The following two formulas correspond to formula C1 and formula C2 in the above-mentioned feature (C): (2π / 550)×(n-1)×Dh<2π ... formula C1 (2π / 550)×2×Dh≧2π ... formula C2

[0222] The method or step of selecting an antiglare sheet may include a step of obtaining the height distribution width Dh (nm) of one of the plurality of peaks 36a and the plurality of bottoms 37a, and a step of confirming that the following two formulas are satisfied. The following two formulas use the wavelength λ (nm) of light incident on the antiglare sheet with the maximum radiant flux (W) and the refractive index n of the portion that constitutes the uneven surface 31X of the antiglare layer 30. The following two formulas correspond to formula B1 and formula B2 in the above-mentioned feature (B). (2π / λ)×(n-1)×Dh<2π ... formula B1 (2π / λ)×2×Dh≧2π ... formula B1

[0223] The substrate 20 other than the antiglare layer 30 included in the antiglare sheet 10 will be described.

[0224] The substrate 20 supports the antiglare layer 30. As shown in Figures 2 and 3, the substrate 20 may constitute the second surface 12 of the antiglare sheet 10. The second surface 12 may be a flat surface. The second surface 12 may be a surface perpendicular to the first direction D1.

[0225] The substrate 20 may be transparent. Transparent means that the total light transmittance is 50% or more, and may be 70% or more, 80% or more, or 90% or more.

[0226] The material of the substrate 20 is not particularly limited, and may be resin or glass. Resin is preferable because it is lightweight and easy to manufacture.

[0227] The resin used for the substrate 20 may be an olefin-based resin such as polyethylene or polypropylene. The resin used for the substrate 20 may be a vinyl-based resin such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, or ethylene-vinyl alcohol copolymer. The resin used for the substrate 20 may be an ester-based resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate. The resin used for the substrate 20 may be an acrylic-based resin such as polymethyl(meth)acrylate or polyethyl(meth)acrylate. The resin used for the substrate 20 may be a styrene-based resin such as polystyrene, a polyamide-based resin such as nylon 6 or nylon 66, or a cellulose-based resin such as triacetyl cellulose. Further examples of resins used for the substrate 20 include resins such as polycarbonate, polyimide-based resins, and cycloolefin resins obtained from cycloolefins such as norbornene and dicyclopentadiene. The antiglare layer 30 may contain only one of the above-mentioned resins, or two or more of the above-mentioned resins.

[0228] A substrate containing a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate may be stretched. The stretching may be uniaxial stretching. The stretching may be biaxial stretching. The stretched substrate containing a polyester-based resin has birefringence. The retardation Re of the stretched substrate containing a polyester-based resin may be adjusted.

[0229] The thickness of the resin substrate 20 is not particularly limited. From the viewpoint of ease of handling, the thickness of the resin substrate 20 may be 10 μm or more, 20 μm or more, or 50 μm or more. The thickness of the resin substrate 20 may be 500 μm or less, 400 μm or less, or 300 μm or less. The thickness of the glass substrate 20 may be 500 μm or more. The thickness of the glass substrate 20 may be 5 mm or less.

[0230] The substrate 20 may include only a single layer or multiple layers. The substrate 20 may include a primer layer such as an easy-adhesion layer.

[0231] The optical function of the antiglare sheet 10 having the above-described structure will now be described.

[0232] The antiglare sheet 10 having the characteristic (A1) can improve both the antiglare property and the glossy appearance, as demonstrated by the experimental results described below. The main reason why the characteristic (A1) enables the antiglare property and the glossy appearance to be simultaneously achieved is presumed to be as follows.

[0233] <Feature (A1)> The cross-sectional profile of each of the plurality of unit element portions 35 is convex upward in the central portion 38 and convex downward in the peripheral portion 39, or is convex downward in the central portion 38 and convex upward in the peripheral portion 39.

[0234] In conventional antiglare sheets, the textured surface of the antiglare layer has been formed by incorporating particles or by blasting. In conventional antiglare sheets, optical properties such as haze, image clarity, and specular gloss have been adjusted by focusing on materials, manufacturing conditions, processing conditions, etc. However, it has been impossible to significantly adjust optical properties through materials, manufacturing conditions, processing conditions, etc. As a result, conventional antiglare sheets have been able to adjust one optical property, but have been unable to fully achieve two or more contradictory optical properties. For example, conventional antiglare sheets have not been able to fully improve both antiglare properties and glossiness. Conventional antiglare sheets have not been able to achieve both antiglare properties and transmission clarity.

[0235] 21A and 21B are cross-sectional views showing a conventional anti-glare sheet 80. A unit element portion 81 included in the conventional anti-glare sheet 80 has a simple shape. Giving the conventional anti-glare sheet 80 a complex shape such as that of feature (A1) has not even been considered.

[0236] FIG. 21A shows a unit element portion 81 that forms a peak portion. FIG. 21B shows a unit element portion 81 that forms a valley portion. As shown in FIGS. 21A and 21B, in a conventional anti-glare sheet 80, the maximum inclination angle θx is usually obtained at the peripheral portion of the unit element portion 81. As shown in FIGS. 21A and 21B, in the anti-glare sheet 10, external light incident from the front direction is reflected approximately evenly in each direction within a wide angle range AR80. In the conventional anti-glare sheet 80, the anti-glare property could be improved by increasing the maximum inclination angle θx. However, in the conventional anti-glare sheet 80, when the anti-glare property was improved, a feeling of cloudiness occurred.

[0237] 6A and 6B show the scattering reflection function of the antiglare sheet 10 having the feature (A1). According to the feature (A1), the inclination angle of the uneven surfaces 11X, 31X relative to the plane perpendicular to the first direction D1 is maximum at the connection position between the central portion 38 and the peripheral portion 39. That is, according to the feature (A1), the maximum inclination position 40 at which the maximum inclination angle θx is obtained is located at the connection position between the central portion 38 and the peripheral portion 39. The unit element portion 35 having the feature (A1) can reduce the inclination angle at the peripheral portion 39.

[0238] 6A and 6B , the unit element portion 35 having the feature (A1) can ensure a wide area of ​​a small inclination angle region while ensuring a sufficiently large maximum inclination angle θx. By ensuring a wide area of ​​a small inclination angle region, much of the external light incident from the front direction can be scattered and reflected in directions within a narrower angle range AR10 than the conventional angle range AR80. By narrowing the angle range of the region where the light is mainly scattered and reflected, it is possible to impart an excellent glossiness to the antiglare sheet 10 while ensuring the necessary antiglare properties.

[0239] On the other hand, by setting the maximum tilt angle θx to a sufficient value, a portion of the external light incident from the front direction can be scattered and reflected in an angle range AR10X that is significantly tilted from the front direction (first direction D1). Therefore, excellent antiglare properties can be imparted to the antiglare sheet 10. When the antiglare sheet 10 is observed from a direction significantly tilted from the front direction, the antiglare sheet 10 can also be effectively prevented from becoming cloudy.

[0240] For the above reasons, it is presumed that the characteristic (A1) can impart excellent antiglare properties and excellent glossiness to the antiglare sheet 10. However, the present embodiment is not bound by the above presumption.

[0241] In the anti-glare sheet 10 described above, each of the plurality of unit element portions 35 is either one of the unit element portions 35 that form the peak portions 36 and the unit element portions 35 that form the valley portions 37. However, in relation to feature (A1), the plurality of unit element portions 35 may include both the unit element portions 35 that form the peak portions 36 and the unit element portions 35 that form the valley portions 37. In this example as well, feature (A1) can improve both the anti-glare properties and the glossy appearance.

[0242] The antiglare sheet 10 having the characteristic (A2) can improve both the antiglare property and the transmitted image clarity, as demonstrated by the experimental results described below. The main reason why the characteristic (A2) can achieve both the antiglare property and the glossy appearance is presumed to be as follows.

[0243] <Feature (A2)> The height of the lowest 5% of the positional distribution of the tops 36a in the first direction D1 is lower than the height of the highest 5% of the positional distribution of the bottoms 37a in the first direction D1.

[0244] In the antiglare layer 30 of the antiglare sheet 10 that satisfies feature (A2), the distribution of the peaks 36a and the distribution of the bottoms 37a overlap in the first direction D1, as shown in FIG. 7 . That is, any peak 36a is located on the second side of any bottom 37a in the first direction D1. Any bottom 37a is located on the first side of any peak 36a in the first direction D1. Feature (A2) compares the height of the peak 36a that is the lowest 5% of the height in the positional distribution in the first direction D1 with the height of the bottom 37a that is the highest 5% of the height in the positional distribution in the first direction D1. Therefore, after removing the effects of outliers, measurement noise, and the like, the distribution of the peaks 36a and the distribution of the bottoms 37a substantially overlap in the first direction D1.

[0245] The distribution of the peaks 36a and the distribution of the bottoms 37a overlap in the first direction D1, so that light diffusion can be expected through the combination of the peaks 36 and the valleys 37. Therefore, the maximum height difference in the uneven surface 31X can be prevented from becoming too large while the light diffusion function of the anti-glare layer 30 and the anti-glare sheet 10 is sufficiently ensured. By sufficiently ensuring the light diffusion function of the anti-glare layer 30 and the anti-glare sheet 10, sufficient anti-glare properties can be imparted to the anti-glare layer 30 and the anti-glare sheet 10. By preventing the maximum height difference in the uneven surface 31X from becoming too large, sufficient transmission clarity and a sufficient glossiness can be imparted to the anti-glare layer 30 and the anti-glare sheet 10.

[0246] For the above reasons, it is presumed that the characteristic (A2) can impart excellent antiglare properties, excellent transmitted light clarity, and excellent glossiness to the antiglare sheet 10. However, the present embodiment is not bound by the above presumption.

[0247] Note that feature (A2) makes it possible to increase the height distribution width Dh (nm) of the peaks 36a and the height distribution width Dh (nm) of the bottoms 37a while preventing the maximum height difference on the uneven surface 31X from becoming too large. Increasing the height distribution width Dh (nm) of the peaks 36a and the height distribution width Dh (nm) of the bottoms 37a can efficiently improve the antiglare properties of the antiglare sheet 10, as will be described later. From this perspective, it can be understood that feature (A2) can impart excellent antiglare properties, excellent transmitted light clarity, and excellent glossiness to the antiglare sheet 10.

[0248] The antiglare sheet 10 having one or more of the features (B) to (E) can improve both the antiglare property and the transmitted light clarity, as demonstrated by the experimental results described below.

[0249] <Feature (B)> One of the peaks 36a and the bottoms 37a is irregularly arranged. The wavelength λ (nm), the height distribution width Dh (nm) of one of the peaks 36a and the bottoms 37a, and the refractive index n of the portion constituting the uneven surface 31X of the antiglare layer 30 satisfy the following two formulas (formula B1 and formula B2): (2π / λ)×(n-1)×Dh<2π Formula B1 (2π / λ)×2×Dh≧2π Formula B2

[0250] <Feature (C)> One of the apexes 36a and the bottoms 37a is arranged irregularly. The height distribution width Dh (nm) of one of the apexes 36a and the bottoms 37a and the refractive index n of the portion constituting the uneven surface 31X of the antiglare layer 30 satisfy the following two formulas (Formula C1 and Formula C2): (2π / 550)×(n-1)×Dh<2π (Formula C1) (2π / 550)×2×Dh≧2π

[0251] <Characteristic D> In addition to characteristic (C), the following four equations are also satisfied: (2π / 450)×(n-1)×Dh<2π ...Equation D1 (2π / 450)×2×Dh≧2π ...Equation D2 (2π / 680)×(n-1)×Dh<2π ...Equation D3 (2π / 680)×2×Dh≧2π ...Equation D4

[0252] <Feature E> In each of features (B) to (D), the following formulas are further satisfied: (2π / λ)×(n-1)×Dh≦π ...equation B1X (2π / 550)×(n-1)×Dh≦π ...equation C1X (2π / 450)×(n-1)×Dh≦π ...equation D1X (2π / 680)×(n-1)×Dh≦π ...equation D3X

[0253] The formulas defined in features (B) to (E) are generally derived as follows:

[0254] First, the amplitude distributions of the transmitted light and the reflected light in the far field are determined based on the height distribution (position distribution in the first direction D1) on the uneven surfaces 11X, 31X of the antiglare sheet 10. Next, the intensity distributions of the transmitted light and the reflected light in the far field are determined from the amplitude distributions of the transmitted light and the reflected light in the far field.

[0255] Then, from the intensity distribution, the light intensity at the optical axis is identified as the peak intensity, and the average of the light intensities near the optical axis is identified as the background intensity. The ratio of the peak intensity to the background intensity is defined as the peak-to-background ratio (= peak intensity / background intensity). Equations B1, C1, D1, D3, and C1X were derived as conditions for making the peak-to-background ratio for transmitted light equal to or greater than a certain level. Equations B2, C2, D2, and D4 were derived as conditions for making the peak-to-background ratio for reflected light equal to or less than a certain level.

[0256] Features (B) to (E) introduce a new concept, such as the peak-to-background ratio, and impose separate conditions on the reflected light and the transmitted light. Features (B) to (E) make it possible to sufficiently scatter the reflected light and suppress scattering of the transmitted light.

[0257] The following provides a more detailed explanation of the method for deriving the meanings defined in features (B) to (E) and their technical significance.

[0258] The surface shape of the anti-glare sheet 10 is represented. Figures 9A, 9B, and 9C schematically show a model of the anti-glare sheet 10 representing the surface shape. As shown in Figure 9A, multiple peaks 36 or multiple valleys 3735 are irregularly arranged. As shown in Figure 9B, the peaks 36 and valleys 37 may constitute unit element portions 35. As shown in Figure 9B, the multiple peaks 36 or multiple valleys 37 have different heights or depths but have the same shape. As shown in Figure 9C, the uneven surfaces 11X and 31X of the anti-glare sheet 10 are located on the (ξ, η) coordinate system.

[0259] The surface shape of the antiglare sheet 10, i.e., the uneven surfaces 11X and 31X, is considered to be a superposition of multiple peaks 36 or multiple valleys 37. The complex amplitude distribution of the wavefront modulated by the uneven surfaces 11X and 31X is expressed by Equation 1a. "i" in Equation 1a is the number of the peak 36 or the multiple valleys 37. (ξi, ηi) are the position coordinates of the peak 36 or the valley 37, and can be approximated as a Poisson distribution. "δ" is a delta function.

[0260]

[0261] In Equation 1a, E(ξ, η) represents the complex amplitude distribution due to one peak 36 or valley 37. Within the range of the peak 36 or valley 37, E(ξ, η) = exp(iθ(ξ, η)). Outside the range of the peak 36 or valley 37, E(ξ, η) = 0.

[0262] θ(ξ,η) represents the phase distribution within one peak 36 or valley 37. Using the height distribution d(ξ,η), the transmitted light is expressed by Equation 1b, and the reflected light is expressed by Equation 1c. Transmission: θ(ξ,η)=(2π / λ)×(n-1)×d(ξ,η) Equation 1b Reflection: θ(ξ,η)=(2π / λ)×2×d(ξ,η) Equation 1c

[0263] "φi" represents the relative phase between the plurality of peaks 36 or the plurality of valleys 37. "φi" is expressed using the relative height Di along the first direction D1 from a certain reference plane RP35 (see FIG. 9B) to the top 36a or bottom 37a. "φi" for transmitted light is expressed by formula 1d, and "φi" for reflected light is expressed by formula 1e. Transmission: φi = (2π / λ) × (n-1) × Di Formula 1d Reflection: φi = (2π / λ) × 2 × Di Formula 1e

[0264] The complex amplitude u(x, y) in the far field is expressed by Fraunhofer diffraction. Specifically, the complex amplitude u(x, y) in the far field can be expressed by Fourier transforming Equation 1a. Equation 2a shows the complex amplitude u(x, y) in the far field. "f" in Equation 2a is the distance from the object plane to the image plane and is set to a sufficiently large value.

[0265]

[0266] In Equation 2a, Σ represents the sum of the peaks 36 or valleys 37 included in the effective area. The effective area may be an area corresponding to one pixel of the display element 66. In Equation 2a, the number i of the peaks 36 or valleys 37 is an integer from 1 to N.

[0267] The intensity distribution I(x, y) in the far field is expressed as the square of the absolute value of the complex amplitude u(x, y), I(x, y) = |u(x, y)|２ The intensity distribution I(x, y) is expressed by Equations 3a and 3b.

[0268]

[0269]

[0270] The peak intensity, which is the light intensity on the optical axis, can be obtained by substituting (x, y) = (0, 0) in Equation 3a. The peak intensity is expressed by Equation 3c.

[0271]

[0272] The light intensity near the optical axis, excluding the optical axis, is calculated by taking into account that the second term of Equation 3b is 0 on average. ０ (x, y) × {N + s(x, y)}" where s(x, y) is a random function that averages to 0. s(x, y) represents the intensity of the speckle. ０ Considering that "(x, y)" changes gradually near the optical axis, the "background intensity" is expressed by the following formula 3d. The background intensity is the average intensity of the light intensity distribution near the optical axis excluding the optical axis. "N" in formula 3d is the number of peaks 36 or valleys 37.

[0273]

[0274] Figure 10 shows an image of the peak intensity expressed by Equation 3c and the background intensity expressed by Equation 3d, where the peak intensity is shown by a dotted line and the background intensity is shown by a solid line.

[0275] The ratio of the peak intensity to the background intensity is defined as the peak-to-background ratio. The peak-to-background ratio is expressed by Equation 3e. As shown in Equation 3e, the peak-to-background ratio is the average of the squares of the absolute values ​​of the sum of vectors representing complex numbers within the effective area.

[0276]

[0277] 11A and 11B show images of the peak background ratio. In Fig. 11A and Fig. 11B, the dashed dotted line is a vector representing the peak background ratio. In Fig. 11A and Fig. 11B, the solid line is a unit vector representing the relative phase for each peak 36 or each valley 37.

[0278] In the example shown in Figure 11A, the directions of the unit vectors representing the relative phase are aligned to a certain extent. That is, the relative phase is biased within a certain range of 2π. In the example shown in Figure 11A, the peak-to-background ratio becomes relatively large. When the relative phase is completely aligned, the peak-to-background ratio expressed by equation 3e becomes N, and the peak-to-background ratio in the actual antiglare sheet 10 becomes infinite.

[0279] In the example shown in Figure 11B, the unit vectors representing the relative phases are divergent. If the relative phases are uniformly distributed over a 2π range, the unit vectors will cancel each other out. As a result, the peak-to-background ratio is small in the example shown in Figure 11B. If the relative phases are not aligned, the peak-to-background ratio will converge to 0 because "N" in the denominator of Equation 3e is a very large value.

[0280] As described above, the formulas defined in features (B) to (E) use "Dh." "Dh" is the height distribution width of the multiple peaks 36a or the multiple bottoms 37a. The height distribution width Dh of the peaks 36a is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the position distribution of the peaks 36a of the peaks 36 in the first direction D1. The height distribution width Dh of the bottoms 37a is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the position distribution of the bottoms 37a of the valleys 37 in the first direction D1.

[0281] 12A shows a histogram of the relative heights Di of the apexes 36a or 37a included in the effective area with a solid line. Fig. 12A also shows a rectangular function with a dotted line. The rectangular function has the same width as the height distribution width Dh. The rectangular function shown in Fig. 12A is obtained by approximating the histogram of the relative heights Di.

[0282] 12B shows a histogram of the relative phase φi of the top 36a or bottom 37a included in the effective area with a solid line. FIG. 12B also shows a rectangular function with a dotted line. The rectangular function has the same width as the phase distribution width φh corresponding to the height distribution width Dh. The rectangular function shown in FIG. 12B is obtained by approximating the histogram of the relative phase φi.

[0283] Similar to the relationship between the relative height Di and the relative phase φi, the phase distribution width φh is determined in relation to the height distribution width Dh. However, the method of calculating the phase distribution width φh differs between transmitted light and reflected light. Figures 13A and 13B show two peaks 36. The positions of the peaks 36a of the two peaks 36 in the first direction D1 differ by the same height as the height distribution width Dh.

[0284] FIG. 13A shows reflected light LXA reflected by a high peak 36X and reflected light LYA reflected by a low peak 36Y. The apex 36a of the high peak 36X and the apex 36a of the low peak 36Y are offset by a length Dh along the first direction D1. In the example shown in FIG. 13A, the optical path length difference between the reflected light LXA and the reflected light LYA is "Dh x 2." The optical path length difference occurs in a region with a refractive index of 1, outside the anti-glare layer 30. Therefore, the phase difference between the reflected light LXA and the reflected light LYA is obtained by dividing the optical path length difference by the wavelength λ and then multiplying by 2π. From this point of view, the following relationship in Equation 4a holds between the phase distribution width φh and the height distribution width Dh for the reflected light. Reflection: φh = (2π / λ) x 2 x Dh Equation 4a

[0285] FIG. 13B shows transmitted light LXB passing through the high peak portion 36X and transmitted light LYB passing through the low peak portion 36Y. The apexes 36a of the high peak portion 36X and the low peak portion 36Y are offset by a length Dh along the first direction D1. In the example shown in FIG. 13B, transmitted light LXB and transmitted light LYB travel a length Dh through the region with different refractive indexes. While transmitted light LXB travels a length Dh through the portion with refractive index n that constitutes the uneven surface, transmitted light LYB travels a length Dh through the region with refractive index 1 outside the anti-glare layer 30. Therefore, transmitted light LXB travels a distance longer than transmitted light LYB by "Dh×n−Dh." The phase difference between reflected light LXA and reflected light LYA is obtained by dividing this optical path length difference by the wavelength λ and then multiplying by 2π. From this point of view, the following relationship of Equation 4b holds true between the phase distribution width φh and the height distribution width Dh for transmitted light: Transmitted: φh = (2π / λ) × (n-1) × Dh Equation 4b

[0286] The relationship between the peak background ratio and the phase distribution width φh is organized by utilizing approximation to a rectangular function. Equation 3e, which indicates the peak background ratio, is converted to the following equation 5a. Under the assumption that the distributions of the relative height Di and the relative phase φi are approximated to rectangular functions, "ΣcosΦi" in equation 5a is expressed as equations 5b to 5d by approximation using integrals. Similarly, "ΣsinΦi" in equation 5a is expressed as equation 5e by approximation using integrals.

[0287] By using Equations 5d and 5e, the peak-to-background ratio is expressed as Equation 5f below: In Equation 5f, the peak-to-background ratio is expressed as a function of the phase distribution width φh.

[0288] Fig. 14 is a graph showing the relationship between the peak-to-background ratio and the phase distribution width φh. In the graph shown in Fig. 14, the vertical axis represents the peak-to-background ratio, and the horizontal axis represents the phase distribution width φh. According to the graph shown in Fig. 14, in order to reduce the peak-to-background ratio, it is effective to set the phase distribution width φh to 2π or more. In order to increase the peak-to-background ratio, it is effective to set the phase distribution width φh to less than 2π. In order to increase the peak-to-background ratio, it is more effective to set the phase distribution width φh to π or less.

[0289] The phase distribution width φh for transmitted light is expressed using the height distribution width Dh by Equation 4b. The phase distribution width φh for reflected light is expressed using the height distribution width Dh by Equation 4a. Figure 15 shows the peak-to-background ratio for transmitted light and the peak-to-background ratio for reflected light in relation to the height distribution width Dh.

[0290] For transmitted light, it is preferable that the peak-to-background ratio is large. When the peak-to-background ratio is large, the intensity of light transmitted in the optical axis direction, i.e., the first direction D1 (front direction), becomes concentratedly high. The intensity of transmitted light traveling in a direction different from the optical axis is reduced. In other words, when the peak-to-background ratio for transmitted light is large, the transmission clarity in the first direction D1 (front direction) can be improved.

[0291] As shown in Figure 14, the peak-to-background ratio can be increased by setting the phase distribution width φh to less than 2π. When Equation 4b, expressed using the height distribution width Dh, is less than 2π, the transmitted light clarity can be improved. That is, when Equation B1 in Feature (B) is satisfied, the transmitted light clarity of the antiglare sheet 10 can be improved. When Equation C1 in Feature (C) is satisfied, the transmitted light clarity of the antiglare sheet 10 for light with a central wavelength in the visible light range can be improved. When Equations D1 and D3 in Feature (D) are further satisfied in addition to Equation C1 in Feature (C), the transmitted light clarity of the antiglare sheet 10 for light across the entire visible light range can be improved.

[0292] Furthermore, as shown in Figure 14, by setting the phase distribution width φh to π or less, the peak-to-background ratio can be significantly increased. When Equation 4b, which is expressed using the height distribution width Dh, is π or less, the transmitted light clarity can be significantly improved. In other words, when Equations B1X, C1X, D1X, and D3X in Feature (E) are satisfied, the transmitted light clarity of the antiglare sheet 10 can be significantly improved.

[0293] For reflected light, it is preferable that the peak-to-background ratio is small. When the peak-to-background ratio is small, the intensity of light reflected in the optical axis direction, i.e., the first direction D1 (front direction), can be reduced. The intensity of reflected light traveling in a direction different from the optical axis can be increased. In other words, when the peak-to-background ratio for reflected light is small, the antiglare properties in the first direction D1 (front direction) can be improved.

[0294] As shown in Figure 14, by setting the phase distribution width φh to 2π or more, the peak-background ratio can be reduced. When Equation 4a, expressed using the height distribution width Dh, is 2π or more, the antiglare properties can be improved. That is, when Equation B2 in Feature (B) is satisfied, the antiglare properties of the antiglare sheet 10 can be improved. When Equation C2 in Feature (C) is satisfied, the antiglare properties of the antiglare sheet 10 against light with a central wavelength in the visible light range can be improved. When Equations D2 and D4 in Feature (D) are further satisfied in addition to Equation C2 in Feature (C), the antiglare properties of the antiglare sheet 10 against light over the entire visible light range can be improved.

[0295] As shown in Figure 15, there is a height distribution width Dh that can increase the peak-to-background ratio for transmitted light and decrease the peak-to-background ratio for reflected light. Therefore, when formulas B1 and B2 in feature (B) are satisfied, both antiglare properties and transmitted image clarity can be improved. When formulas C1 and C2 in feature (C) are satisfied, both antiglare properties and transmitted image clarity for light with a central wavelength in the visible light range can be improved. When formulas D1 to D4 in feature (D) are satisfied in addition to formulas C1 and C2 in feature (C), both antiglare properties and transmitted image clarity for light across the entire visible light range can be improved.

[0296] For the above reasons, it is presumed that the features (B) to (E) can impart excellent antiglare properties and excellent transmitted light clarity to the antiglare sheet 10. However, the present embodiment is not bound by the above presumption.

[0297] As in the anti-glare sheet 10 described above, one of the peaks 36a and the bottoms 37a may be irregularly arranged, and the height distribution width Dh (nm) of one of the peaks 36a and the bottoms 37a may satisfy one or more of the features (B) to (E). This example is not limited to this, and both the peaks 36a and the bottoms 37a may be irregularly arranged, and the height distribution width Dh (nm) of both the peaks 36a and the bottoms 37a may satisfy one or more of the features (B) to (E). This example can impart even better anti-glare properties and even better transmission clarity to the anti-glare sheet 10.

[0298] As in the anti-glare sheet 10 described above, the unit element portion 35 having the characteristic (A1) may constitute one of the top portion 36a and the bottom portion 37a. The height distribution width Dh (nm) of one of the top portion 36a and the bottom portion 37a may satisfy one or more of the characteristics (B) to (E). In this example, the height distribution width Dh (nm) of the other of the top portion 36a and the bottom portion 37a may satisfy one or more of the characteristics (B) to (E). This example provides the anti-glare sheet 10 with even better anti-glare properties and even better transmission clarity.

[0299] As yet another example, the anti-glare sheet 10 may include a first unit element portion 35 having the characteristic (A1) and a second unit element portion 35 having the characteristic (A1). The first unit element portion 35 may constitute one of the top portion 36a and the bottom portion 37a. The second unit element portion 35 may constitute the other of the top portion 36a and the bottom portion 37a. In this example, the height distribution width Dh (nm) of one of the top portion 36a and the bottom portion 37a of the first unit element portion 35 may satisfy one or more of the characteristics (B) to (E), and the height distribution width Dh (nm) of the other of the top portion 36a and the bottom portion 37a of the second unit element portion 35 may satisfy one or more of the characteristics (B) to (E). This example provides the anti-glare sheet 10 with even better anti-glare properties and even better transmission clarity.

[0300] Here, the results of experiments conducted by the present inventors will be described. The present inventors produced samples 1 to 4 of the antiglare sheet 10 according to the following procedure. Then, the optical properties of samples 1 to 4 were evaluated. The shapes of the uneven surface 31X were different between samples 1 to 4. The materials and manufacturing methods used were the same between samples 1 to 4.

[0301] First, the shape of the uneven surface 31X of the antiglare layer 30 was designed in the following procedure: determining the shape of the uneven surface 31X; provisionally determining the arrangement of the plurality of peaks 36; adjusting the arrangement of the plurality of peaks 36; and smoothing the cross-sectional contour at the connection between two adjacent peaks 36.

[0302] In the process of determining the shape of the uneven surface 31X, the peaks 36 were unit element portions 35 having a cross-sectional profile along a Gaussian function for Samples 1 to 4. As will be described later, Samples 1 to 4 had the above-mentioned characteristics (A1) and (A2).

[0303] In the step of provisionally determining the arrangement, the arrangement of the peaks 36a of the plurality of peaks 36 was provisionally determined as shown in Fig. 16. In the step of adjusting the arrangement, the arrangement of the peaks 36a of the plurality of peaks 36 was determined as shown in Fig. 4. In the step of smoothing the cross-sectional contour, the cross-sectional contour was adjusted at the portion where two adjacent peaks 36 connected, as shown in Fig. 17, so that the two peaks 36 were smoothly connected.

[0304] A mold was created to create the designed cross-sectional shape. A shape complementary to the designed cross-sectional shape was given to the mold surface. The mold surface was formed by laser drawing.

[0305] A substrate made of triacetyl cellulose (TAC) was prepared. A coating liquid containing an ultraviolet-curable resin composition was prepared. The coating liquid was applied to the substrate to form a coating film on the substrate. With the mold surface of the mold in contact with the coating film, the ultraviolet-curable resin composition located between the mold and the substrate was cured. An antiglare layer 30 was produced as a cured product of the ultraviolet-curable resin composition in a state bonded to the substrate 20. In this way, samples 1 to 4 of antiglare sheets including the substrate 20 and the antiglare layer 30 were produced. The refractive index of the antiglare layer 30 including the ridges 36 was set to 1.5.

[0306] The cross-sectional profiles of Samples 1 to 5 prepared according to the above-described procedures (M1) to (M6) were evaluated. All of Samples 1 to 5 had the characteristic (A1). A laser microscope "VK-X1000" manufactured by Keyence Corporation was used to obtain the surface shapes of Samples 1 to 5.

[0307] In Samples 1 to 5, a plurality of peaks 36 were formed, and valleys 37 including bottoms 37a were formed at positions surrounded by the plurality of peaks 36. According to the above-described steps (L1) to (L4), the positional distribution of the peaks 36a in the first direction D1 and the positional distribution of the bottoms 37a in the first direction D1 were obtained. A laser microscope "VK-X1000" manufactured by Keyence Corporation was used to obtain the positional distribution of the peaks 36a and bottoms 37a for Samples 1 to 4.

[0308] Based on the positional distribution of the tops 36a in the first direction D1, a height that is 5% from the lowest in the positional distribution of the tops 36a in the first direction D1 was identified. Based on the positional distribution of the bottoms 37a in the first direction D1, a height that is 5% from the highest in the positional distribution of the bottoms 37a in the first direction D1 was identified. Based on the above measurement results, samples 1 to 4 had characteristic (A2).

[0309] As an example, in sample 3, the height of the top 36a at 5% from the bottom in the position distribution in the first direction D1 was 0.374 μm, and the height of the bottom 37a at 5% from the top in the position distribution in the first direction D1 was 0.453 μm.

[0310] The height distribution width Dh of the apex 36a was measured for the prepared samples 1 to 4 according to the above-described procedures (N1) to (N4). A laser microscope "VK-X1000" manufactured by Keyence Corporation was used to measure the height distribution width. The measurement results of the height distribution width Dh of the apex 36a are shown in the "Dh" column of Table 1.

[0311] The values ​​of the left sides of Equations C1 and C2 defined in Feature (C) were calculated for each of Samples 1 to 4, with the measured height distribution width Dh and refractive index n set to 1.5. The values ​​of the left sides of Equations C1 and C2 are shown in the "Equation C1" and "Equation C2" columns of Table 1. A determination was also made for each of Samples 1 to 4 as to whether or not Feature (C) was satisfied. For samples that satisfied Feature (C), an "A" was added to the "Decision" column of Table 1. For samples that did not satisfy Feature (C), a "B" was added to the "Decision" column of Table 1.

[0312] The transmission haze of the prepared Samples 1 to 4 was measured by the method described above. The transmission haze was measured using a haze meter "HM-150" manufactured by Murakami Color Research Laboratory. The measurement results of the transmission haze are shown in the "Haze" column of Table 1.

[0313] The image clarity of the prepared Samples 1 to 4 was measured by the transmission method using a 0.5 mm wide optical comb as described above. The image clarity was measured using an image clarity measuring instrument "ICM-1T" manufactured by Suga Test Instruments Co., Ltd. The measurement results of image clarity are shown in the "Clarity" column of Table 1.

[0314] For the prepared Samples 1 to 4, the specular gloss Gs(60) of the first surface was measured using the method described above at an incident angle of 60°. The specular gloss was measured using a gloss meter GM-26PRO manufactured by Murakami Color Research Laboratory. The measurement results of the specular gloss are shown in the "Gloss" column of Table 1.

[0315] For the fabricated Samples 1 to 4, the reflected zeroth-order light intensity at 0° incidence on the first surface, where the incident angle was set to 0°, was measured using the method described above. The radiant flux (W) was measured using an optical power meter "8230E" manufactured by ADC. The measurement results of the reflected zeroth-order light intensity at 0° incidence are shown in the "Reflected Zeroth Order" column in Table 1.

[0316]

[0317] All of Samples 1 to 4, which satisfied Features (A1) and (A2), had excellent antiglare properties, excellent transmission clarity, and excellent gloss. All of Samples 1 to 4, which satisfied Features (A1) and (A2), had the quality to be acceptable as antiglare sheets to be applied to display devices. Samples 1 and 2, which satisfied Feature (C), in particular, had both excellent antiglare properties and excellent transmission clarity.

[0318] The first antiglare sheet 10 according to the present embodiment described above includes a first surface 11 and a second surface 12 that face each other in the first direction D1. The antiglare sheet 10 includes an antiglare layer 30 that includes an uneven surface 31X. The uneven surface 31X includes a plurality of peaks and a plurality of valleys. The uneven surface 31X faces the opposite side from the second surface 12 in the first direction D1. The antiglare layer 30 includes a plurality of unit element portions 35 that form the uneven surface 31X. The cross-sectional profile of each of the unit element portions 35 is convex upward at a central portion 38 and convex downward at a peripheral portion 39 connected to the central portion 38, or is convex downward at the central portion 38 and convex upward at the peripheral portion 39. Each of the plurality of peaks 36 forms a peak 36a of the uneven surface 31X. Each of the plurality of valleys 37 forms a bottom 37a of the uneven surface 31X. The height of the top 36a, which is 5% from the lowest in the positional distribution in the first direction D1, is lower than the height of the bottom 37a, which is 5% from the highest in the positional distribution in the first direction D1. The first antiglare sheet 10 according to this embodiment can improve antiglare properties, transmitted light clarity, and glossiness.

[0319] The first selection method according to the present embodiment described above relates to an anti-glare sheet 10 including a first surface 11 and a second surface 12 that face each other in a first direction D1. The anti-glare sheet 10 includes an anti-glare layer 30 that includes an uneven surface 31X. The uneven surface 31X includes a plurality of peaks and a plurality of valleys. The uneven surface 31X faces the opposite side from the second surface 12 in the first direction D1. The anti-glare layer 30 includes a plurality of unit element portions 35 that constitute the uneven surface 31X. Each of the plurality of peaks 36 forms a peak 36a of the uneven surface 31X. Each of the plurality of valleys 37 forms a bottom 37a of the uneven surface 31X. The selection method includes the steps of acquiring cross-sectional contours of at least some of the unit element portions 35, confirming the cross-sectional contours, acquiring positional portions, and confirming the positional portions. In the step of checking the cross-sectional contour, it is confirmed that the cross-sectional contour is convex upward at the central portion 38 and convex downward at the peripheral portion 39 connected to the central portion 38, or convex downward at the central portion 38 and convex upward at the peripheral portion 39. In the step of acquiring positional portions, the positional distribution of the tops 36a in the first direction D1 and the positional distribution of the bottoms 37a in the first direction D1 are acquired. In the step of confirming the positional portions, it is confirmed that the height of the lowest 5% of the positional distribution of the tops 36a in the first direction D1 is lower than the height of the highest 5% of the positional distribution of the bottoms 37a in the first direction D1. According to the first selection method of this embodiment, it is possible to stably supply anti-glare sheets 10 having both excellent anti-glare properties and excellent glossiness.

[0320] Although the present embodiment has been described with reference to specific examples, the above-described specific examples do not limit the present embodiment. The above-described embodiment can be implemented with various other specific examples, and various omissions, substitutions, changes, additions, etc. can be made without departing from the spirit of the present invention.

[0321] An example of the modification will be described below with reference to the drawings. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described specific example will be designated by the same reference numerals as those used for the corresponding parts in the above-described specific example, and duplicated descriptions will be omitted.

[0322] 1, the antiglare sheet 10 is applied to a display device 65. However, the application of the antiglare sheet 10 is not limited to the display device 65.

[0323] The antiglare sheet 10 may be applied to a polarizing plate 60. In the example shown in FIG. 18 , the polarizing plate 60 includes a first protective sheet 61, a polarizer 62, and a second protective sheet 63. The first protective sheet 61 and the second protective sheet 63 sandwich the polarizer 62 between them and cover the polarizer 62 from both sides. At least one of the first protective sheet 61 and the second protective sheet 63 may include the antiglare sheet 10. The first protective sheet 61 located on the first side (viewer side) in the first direction D1 may include the antiglare sheet 10. When only one of the first protective sheet 61 and the second protective sheet 63 includes the antiglare sheet 10, the other protective sheet may be a resin film.

[0324] The polarizer 62 transmits one linearly polarized component and blocks the other linearly polarized component. The polarizer 62 may be an absorptive polarizer that absorbs the other linearly polarized component. The polarizer 62 may be a reflective polarizer that reflects the other linearly polarized component. The polarizer 62 may be a sheet-type polarizer such as a stretched polyvinyl alcohol film, polyvinyl formal film, polyvinyl acetal film, or saponified ethylene-vinyl acetate copolymer film dyed with iodine or the like. The polarizer 62 may be a wire-grid polarizer made of a large number of metal wires arranged in parallel. The polarizer 62 may be a coated polarizer coated with a lyotropic liquid crystal or a dichroic guest-host material, or a multilayer thin-film polarizer.

[0325] The antiglare sheet 10 can be used in a variety of applications. FIG. 19 shows a panel 70 to which the antiglare sheet 10 is applied. The panel 70 includes the antiglare sheet 10 and a bonded article 71 to which the antiglare sheet 10 is bonded. The panel 70 constitutes an antiglare article having an antiglare function using the antiglare sheet 10. The panel 70 as an antiglare article suppresses background reflections due to its antiglare function. The antiglare sheet 10 is overlaid on the bonded article 71 with its second surface 12 facing the bonded article 71. The antiglare sheet 10 may be bonded to the bonded article 71 via a bonding layer containing an adhesive or a pressure-sensitive adhesive. Examples of the bonded article 71 include an instrument panel, a clock, a showcase, a show window, a window, and a front panel of a display device. The bonded article 71 may be a transparent substrate such as glass or a resin film.

[0326] As shown in FIG. 20 , for one or more of the peaks 36, valleys 37, and unit element portions 35, the dimension L352 in the second direction D2 perpendicular to the first direction D1 may be smaller than the dimension L353 in the third direction D3 perpendicular to both the first direction D1 and the second direction D2. For one or more of the peaks 36, valleys 37, and unit element portions 35, the dimension L382 of the central portion 38 in the second direction D2 perpendicular to the first direction D1 may be smaller than the dimension L383 of the central portion 38 in the third direction D3 perpendicular to both the first direction D1 and the second direction D2. According to these examples, light scattering in the second direction D2 in the unit element portions 35 is stronger than light scattering in the third direction D3. In other words, light scattering in the third direction D3 in the unit element portions 35 is suppressed more than light scattering in the second direction D2. This modification provides the antiglare layer 30 with an anisotropic light-scattering function. For example, in a display device, light scattering in the horizontal direction may be promoted more than in the vertical direction. In the example shown in Fig. 20, the second direction D2 may be aligned with the horizontal direction. According to this modification, excessive light scattering can be avoided and appropriate antiglare properties can be imparted. By avoiding excessive light scattering, a decrease in glossiness and a decrease in transmitted image clarity can be suppressed.

[0327] D1: first direction, D2: second direction, D3: third direction, 5: sheet article, 6: winding core, 7: roll, RA: winding axis, 10: antiglare sheet, 11: first surface, 11X: uneven surface, 12: second surface, 20: substrate, 30: antiglare layer, 31: first surface, 31X: uneven surface, 32: second surface, 34: main body, 35: unit element, 36: peak, 36a: peak, 37: valley, 37a: bottom, 38: center, 39: peripheral portion, 40: maximum inclination position, 60: polarizing plate, 61: first protective sheet, 62: polarizer, 63: second protective sheet, 65: display device, 66: display element, 66a: image forming surface, 70: antiglare article, 71: bonded article, 80: antiglare sheet, 81: unit element

Claims

1. An anti-glare sheet comprising: an anti-glare layer having a first surface and a second surface opposing each other in a first direction; and including an uneven surface including a plurality of peaks and a plurality of valleys; the uneven surface faces the opposite side to the second surface in the first direction; the anti-glare layer including a plurality of unit element parts constituting at least a part of one of the plurality of peaks or the plurality of valleys; the cross-sectional outline of each of the plurality of unit element parts is convex upward in a central part and convex downward in a peripheral part connected to the central part, or is convex downward in the central part and convex upward in the peripheral part; each of the plurality of peaks forms a peak of the uneven surface, and each of the plurality of valleys forms a bottom of the uneven surface; and the height of the peaks, which are 5% from the lowest in a positional distribution in the first direction, is lower than the height of the bottoms, which are 5% from the highest in a positional distribution in the first direction.

2. The anti-glare sheet according to claim 1, wherein one of the tops and bottoms constituted by the unit element parts is irregularly arranged within the plane, and the height distribution width Dh (nm) of said one of the tops and bottoms and the refractive index n of the portion constituting the uneven surface of the anti-glare layer satisfy the following two formulas: (2π / 550) × (n-1) × Dh < 2π (2π / 550) × 2 × Dh ≧ 2π The height distribution width Dh of the tops is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the positional distribution of the tops in the first direction, and the height distribution width Dh of the bottoms is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the positional distribution of the bottoms in the first direction.

3. The antiglare sheet according to claim 2, wherein the following formula is satisfied: (2π / 550)×(n−1)×Dh≦π.

4. The anti-glare sheet according to claim 1, wherein one of the tops and bottoms constituted by the unit element parts is irregularly arranged, and the wavelength λ (nm), the height distribution width Dh (nm) of said one of the tops and bottoms, and the refractive index n of the portion constituting the uneven surface of the anti-glare layer satisfy the following two formulas: (2π / λ)×(n-1)×Dh<2π (2π / λ)×2×Dh≧2π The wavelength λ is the wavelength of light incident on the anti-glare sheet with the maximum radiant flux (W), The height distribution width Dh of the tops is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the positional distribution of the tops in the first direction, and The height distribution width Dh of the bottoms is the difference between the height that is 10% from the top and the height that is 10% from the bottom in the positional distribution of the bottoms in the first direction.

5. The antiglare sheet according to claim 4, wherein the following formula is satisfied: (2π / λ)×(n−1)×Dh≦π.

6. The antiglare sheet according to any one of claims 1 to 5, wherein in at least some of the plurality of unit element parts, the peripheral part circumferentially surrounds the central part.

7. An anti-glare sheet according to any one of claims 1 to 5, wherein the anti-glare layer comprises a plurality of second unit element parts that constitute at least a portion of the other of the plurality of peaks and the plurality of valleys, and the cross-sectional contour of each of the plurality of second unit element parts is convex downward in the central part and convex upward in the peripheral part connected to the central part, or is convex upward in the central part and convex downward in the peripheral part.

8. An anti-glare sheet as described in any one of claims 1 to 5, wherein the dimension of the central portion of each of the plurality of unit element portions in a second direction perpendicular to the first direction is smaller than the dimension of the central portion in a third direction perpendicular to both the first direction and the second direction.

9. The antiglare sheet according to any one of claims 1 to 5, wherein the transmission haze is 75% or less.

10. The antiglare sheet according to any one of claims 1 to 5, which has an image clarity of 5.0% or more when measured by a transmission method using an optical comb having a width of 0.5 mm.

11. The antiglare sheet according to any one of claims 1 to 5, wherein the specular gloss Gs(60) of the first surface at an incident angle of 60° is 8.0% or more.

12. The antiglare sheet according to any one of claims 1 to 5, wherein the intensity of reflected zero-order light incident at an angle of 0° on the first surface is 20% or less.

13. A sheet product comprising a plurality of antiglare sheets according to any one of claims 1 to 5.

14. The sheet article of claim 13, wound about a winding axis.

15. A polarizing plate comprising: an antiglare sheet according to any one of claims 1 to 5; and a polarizer superimposed on the antiglare sheet.

16. A display device comprising: an antiglare sheet according to any one of claims 1 to 5; and a display element superimposed on the antiglare sheet.

17. A panel comprising: an article to be joined; and the antiglare sheet according to any one of claims 1 to 5 joined to the article to be joined.

18. An anti-glare sheet including a first surface and a second surface opposing each other in a first direction, the anti-glare sheet comprising an anti-glare layer including an uneven surface including a plurality of peaks and a plurality of valleys, the uneven surface facing the opposite side to the second surface in the first direction, the anti-glare layer including a plurality of unit element portions constituting at least a portion of one of the plurality of peaks and the plurality of valleys, each of the plurality of peaks forming a peak of the uneven surface and each of the plurality of valleys forming a bottom of the uneven surface, the anti-glare sheet comprising: a step of acquiring a cross-sectional profile of at least a portion of the plurality of unit element portions; a step of confirming that the cross-sectional profile is convex upward at a central portion and convex downward at a peripheral portion connected to the central portion, or is convex downward at the central portion and convex upward at the peripheral portion; and a step of acquiring a positional distribution of the peaks in the first direction and a positional distribution of the bottoms in the first direction. A method for selecting an antiglare sheet, comprising a step of confirming that the height of the top portion that is 5% from the lowest in the position distribution in the first direction is lower than the height of the bottom portion that is 5% from the highest in the position distribution in the first direction.

19. A method for manufacturing an anti-glare sheet, the method comprising: a step of manufacturing an anti-glare sheet having a first surface and a second surface facing each other in a first direction, the anti-glare sheet comprising an anti-glare layer including an uneven surface including a plurality of peaks and a plurality of valleys, the uneven surface facing the opposite side to the second surface in the first direction, the anti-glare layer including a plurality of unit element parts constituting at least a part of one of the plurality of peaks and the plurality of valleys, each of the plurality of peaks forming a peak of the uneven surface and each of the plurality of valleys forming a bottom of the uneven surface; and a step of selecting the anti-glare sheet by the selection method described in claim 18.

20. A method for producing an anti-glare sheet according to any one of claims 1 to 5, comprising the steps of: determining the shape of the uneven surface; and shaping the uneven surface.

21. A method for manufacturing an antiglare sheet according to claim 20, wherein in the step of determining the shape of the uneven surface, it is confirmed that the cross-sectional contour is convex upward in the central portion and convex downward in the peripheral portion connected to the central portion, or convex downward in the central portion and convex upward in the peripheral portion, and it is confirmed that the height of the lowest 5% of the top portions in the positional distribution in the first direction is lower than the height of the highest 5% of the bottom portions in the positional distribution in the first direction.

22. A method for manufacturing an antiglare sheet as described in claim 20, wherein in the step of determining the shape of the uneven surface, the cross-sectional contours of the plurality of peaks and valleys are provisionally determined, and the provisionally determined cross-sectional contours are smoothed at the portions where two adjacent peaks, two adjacent valleys, or adjacent peaks and valleys are connected among the plurality of peaks and valleys.

23. A method for manufacturing an antiglare sheet as described in claim 20, wherein in the step of determining the shape of the uneven surface, the cross-sectional contours of the plurality of unit element parts are provisionally determined, and the provisionally determined cross-sectional contours are smoothed at the portion where two adjacent unit element parts of the plurality of unit element parts are connected.

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