Optical sheet, sheet article, polarizing plate, display device, panel, method for selecting optical sheet, and method for manufacturing optical sheet

Abstract

An optical sheet includes a first surface and a second surface that are opposite in a first direction. The optical sheet contains an antiglare layer and a functional layer in this order from the second surface toward the first surface. A transmission haze is 10% or more and 70% or less. The functional layer contains a binder component and hollow silica particles. An appropriate coordination parameter of the hollow silica particles observed in the first surface is 1.0 or more and 2.0 or less. The appropriate coordination parameter is a value obtained by subtracting an inappropriate coordination number from an appropriate coordination number. The appropriate coordination number is the number of other hollow silica particles whose centers of gravity are located at a distance of 55 nm or more and less than 75 nm from the center of gravity of one hollow silica particle. The inappropriate coordination number is the number of other hollow silica particles whose centers of gravity are located at a distance of less than 55 nm from the center of gravity of the one hollow silica particle.

Description

Technical Field

[0001] This disclosure relates to optical sheets, sheet articles, polarizers, display devices, panels, methods for selecting optical sheets, and methods for manufacturing optical sheets. Background Technology

[0002] As disclosed in Patent Document 1 (JP2022-15702A), optical sheets comprising an anti-glare layer and a functional layer are known. The anti-glare layer has an anti-glare function. The anti-glare layer suppresses background images from being reflected onto the surface of the optical sheet. The functional layer comprises hollow silica particles. The functional layer has a function of suppressing reflections.

[0003] As an example, optical sheets can be applied to display devices. Examples of display devices include televisions, display devices assembled in laptop PCs and desktop PCs, and display devices assembled in smartphones or tablets. Optical sheets constitute the outermost surface of a display device.

[0004] As described in Patent Document 1, hues are sometimes observed in optical sheets containing a functional layer that has a reflection suppression function.

[0005] Hue may be observed in optical sheets containing a functional layer with anti-reflection properties. In optical sheets containing both an anti-glare layer and a functional layer, hue is easily observed when the background of the optical sheet is dark. For example, when the display element is not displaying anything, the optical sheet attached to the display element will not be observed as black, but rather a hue will be observed on the optical sheet. Summary of the Invention

[0006] The purpose of this invention is to suppress the tint observed in optical films containing anti-glare layers and functional layers.

[0007] In one embodiment of this disclosure, the optical sheet is an optical sheet comprising a first surface and a second surface opposite to each other in a first direction, wherein, The optical sheet comprises an anti-glare layer and a functional layer in order from the second surface toward the first surface. The transmission haze of the optical sheet is above 10% and below 70%. The functional layer comprises an adhesive component and hollow silica particles. Based on the observation on the first surface, the appropriate coordination parameter of the hollow silica particles is above 1.0 and below 2.0. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a hollow silica particle. The inappropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of less than 55 nm from the centroid of the hollow silica particle.

[0008] In one embodiment of this disclosure, the method for selecting an optical sheet includes the following steps: For the optical sheet, the step of determining appropriate coordination parameters based on hollow silica particles observed on the first surface, the optical sheet comprising a first surface and a second surface opposite each other in a first direction, and including an anti-glare layer and a functional layer in order from the second surface toward the first surface, the optical sheet having a transmission haze of 10% or more and 70% or less, the functional layer comprising an adhesive component and the hollow silica particles; and The steps for selecting an optical sheet with a suitable coordination parameter of 1.0 or higher and 2.0 or lower. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a single hollow silica particle. The inappropriate coordination number is the number of hollow silica particles whose center of gravity is located at a distance of less than 55 nm from the center of gravity of the hollow silica particle.

[0009] In one embodiment of this disclosure, a method for manufacturing an optical sheet includes: the step of manufacturing the optical sheet; and the step of selecting the optical sheet using an optical sheet selection method according to one embodiment of this disclosure.

[0010] According to the present invention, it is possible to suppress the tint observed in an optical film containing an anti-glare layer and a functional layer. Attached Figure Description

[0011] Figure 1 This is a diagram used to illustrate one embodiment, and is a cross-sectional view showing an example of an optical sheet.

[0012] Figure 2A It is shown Figure 1 A cross-sectional view of an example of a functional layer that can be included in a system.

[0013] Figure 2B It is shown Figure 1 A cross-sectional view of other examples of functional layers that may be included in the process.

[0014] Figure 3A This is a diagram used to illustrate appropriate coordination parameters; it is a top view showing an example of an optical sheet.

[0015] Figure 3B This is a diagram used to illustrate appropriate coordination parameters, and a top view showing other examples of optical plates.

[0016] Figure 3C This is a diagram used to illustrate appropriate coordination parameters, and it is a top view showing another example of an optical sheet.

[0017] Figure 4A This is an observation image of the first side of an example of an actually manufactured optical sheet.

[0018] Figure 4B Yes Figure 4A The image after binarization of the observed image.

[0019] Figure 4C It is shown Figure 4A An image showing the distribution of the centroids of the hollow silica particles contained in the observed image.

[0020] Figure 5 This is a cross-sectional view showing other examples of optical sheets.

[0021] Figure 6 This is a perspective view showing an example of a sheet article containing optical plates.

[0022] Figure 7 This is a cross-sectional view showing an example of a polarizer containing optical plates.

[0023] Figure 8 This is a cross-sectional view showing an example of a display device including an optical sheet.

[0024] Figure 9 This is a cross-sectional view showing an example of a panel containing optical sheets. Detailed Implementation

[0025] One embodiment of this disclosure relates to the following <1> ~ <14> .

[0026] <1>

[0027] An optical sheet comprising a first surface and a second surface opposite each other in a first direction, wherein, The optical sheet comprises an anti-glare layer and a functional layer in order from the second surface toward the first surface. The transmission haze of the optical sheet is above 10% and below 70%. The functional layer comprises an adhesive component and hollow silica particles. Based on the observation on the first surface, the appropriate coordination parameter of the hollow silica particles is above 1.0 and below 2.0. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a hollow silica particle. The inappropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of less than 55 nm from the centroid of the hollow silica particle.

[0028] <2>

[0029] according to <1> The optical sheet, wherein, Measured using the reflected light from the first surface Color system Values ​​above -4.0 and below 4.0 Measured using the reflected light from the first surface Color system Values ​​are above -4.0 and below 4.0.

[0030] <3>

[0031] according to <1> or <2> The optical sheet wherein the standard deviation of the appropriate coordination parameter is less than 0.30.

[0032] <4>

[0033] according to <1> ~ <3> The optical sheet described in any one of the following statements, wherein, The apparent reflectance of the first surface is compared with that measured using reflected light. Color system The absolute value of the product of values ​​is less than 4.0. The visual reflectance and the reflectance measured using reflected light Color system The absolute value of the product of values ​​is less than 4.0.

[0034] <5>

[0035] according to <1> ~ <4> The optical sheet according to any one of the following methods, wherein the visual reflectance of the first surface is 2.0% or less.

[0036] <6>

[0037] according to <1> ~ <5> The optical sheet described in any one of the following statements, wherein, The anti-glare layer includes uneven surfaces. The concave-convex surface is closer to the first surface in the first direction than the second surface. The concave-convex surface includes a reference portion and a protrusion protruding from the reference portion. The appropriate coordination parameter is a value measured in the region of the first surface opposite to the reference part in the first direction.

[0038] <7>

[0039] according to <1> ~ <6> The optical sheet described in any one of the following statements, wherein, The anti-glare layer comprises resin and particles. The appropriate coordination parameter is a value measured in the region on the first surface opposite the region of the anti-glare layer where the particles are absent in the first direction.

[0040] <8>

[0041] A type of item that has multiple <1> ~ <7> The optical sheet as described in any one of the following.

[0042] <9>

[0043] according to <8> The sheet-like article is wound around a winding axis.

[0044] <10>

[0045] A panel having <1> ~ <7> The optical sheet as described in any one of the following.

[0046] <11>

[0047] A polarizer having <1> ~ <7> The optical sheet and the polarizing element overlapping the optical sheet as described in any one of the following.

[0048] <12>

[0049] A display device comprising <1> ~ <7> The optical sheet and the display element overlapping the optical sheet as described in any one of the following.

[0050] <13>

[0051] A method for selecting an optical sheet, comprising the following steps: For an optical sheet, the step of determining appropriate coordination parameters based on hollow silica particles observed on a first surface, the optical sheet comprising a first surface and a second surface opposite each other in a first direction, and including an anti-glare layer and a functional layer in order from the second surface toward the first surface, the optical sheet having a transmission haze of 10% or more and 70% or less, the functional layer comprising an adhesive component and the hollow silica particles; and The steps for selecting an optical sheet with a suitable coordination parameter of 1.0 or higher and 2.0 or lower. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a single hollow silica particle. The inappropriate coordination number is the number of hollow silica particles whose center of gravity is located at a distance of less than 55 nm from the center of gravity of the hollow silica particle.

[0052] <14>

[0053] A method for manufacturing an optical sheet, comprising the following steps: The steps for manufacturing the optical sheet; and pass <13> The selection method described herein is the step of selecting the optical sheet.

[0054] In the following sections, details of embodiments of the present disclosure will be described. In the accompanying drawings, for ease of illustration and understanding, scales and aspect ratios relative to actual objects have been appropriately altered and exaggerated.

[0055] In this manual, the terms "sheet," "film," and "plate" are used interchangeably only for different names. For example, "optical sheet" is not different from components called optical film or optical plate, just because of the different names used.

[0056] In this specification, the normal direction of a sheet-like (film-like, plate-like) component refers to the direction parallel to the normal or perpendicular line of the surface (film surface, plate surface) of the sheet-like (film-like, plate-like) component being considered. "Surface (film surface, plate surface)" refers to the surface that coincides with the sheet-like (film-like, plate-like) component being considered when viewed as a whole and globally.

[0057] In this specification, multiple candidates for upper limits and multiple candidates for lower limits related to a numerical range are sometimes stated in different statements. In these statements, the numerical range can also be constructed by combining any candidate for an upper limit and any candidate for a lower limit. For example, consider the statement: "Parameter B can be above A1, above A2, or above A3. Parameter B can be below A4, below A5, or below A6." In this example, the numerical range of parameter B can be above A1 and below A4, above A1 and below A5, above A1 and below A6, above A2 and below A4, above A2 and below A5, above A2 and below A6, above A3 and below A4, above A3 and below A5, or above A3 and below A6.

[0058] To clarify directional relationships between the attached figures, common first, second, and third directions (D1, D2, and D3) are indicated by arrows using common reference numerals across several figures. The tip of the arrow is designated as the first side of each direction, and the opposite side is designated as the second side. For example... Figure 1As shown, arrows pointing inwards from the paper in a direction perpendicular to the paper in the attached drawing are indicated by an "×" symbol placed inside a circle. For example, as... Figure 3A As shown, a symbol with a dot in the center of a circle is used to represent an arrow pointing forward from the paper in a direction perpendicular to the paper in the attached figure.

[0059] <<<Optical Film>>>

[0060] like Figure 1 As shown, the optical sheet 10 of this embodiment includes a first surface 11 and a second surface 12. The first surface 11 and the second surface 12 are opposite to each other in the first direction D1. The first surface 11 faces the side opposite to the second surface 12 in the first direction D1. The first surface 11 may be located on the first side in the first direction D1. The second surface 12 may be located on the second side in the second direction D2. The optical sheet 10 includes an anti-glare layer 30 and a functional layer 40. The anti-glare layer 30 and the functional layer 40 are sequentially disposed from the second surface 12 toward the first surface 11 in the first direction D1.

[0061] The transmission haze of the optical sheet 10 is between 10% and 70%.

[0062] The transmitted haze (%) was measured using a D65 light source. Before measuring the transmitted haze, the D65 light source was lit for 15 minutes to allow its output to stabilize. The incident angle of the sample was set to 0° during the transmitted haze measurement. The incident surface for measuring the transmitted haze of optical plate 10 was the second surface 12. The measurement environment was set to a temperature of 23℃±2℃ and a relative humidity of 50%±5%. The sample was prepared in the measurement environment for 16 hours before the measurement began. Other measurement conditions for transmitted haze were in accordance with JIS K7136:2000.

[0063] Transmitted haze was set as the arithmetic mean of five measurements. These five measurements were taken at five locations on the sample, spaced at least 10 mm apart.

[0064] By setting a lower limit for the transmitted haze of the optical sheet 10, an anti-glare function can be imparted to the optical sheet 10. Based on the optical sheet 10 with the anti-glare function, it is possible to suppress the reflection of background images from the environment in which the optical sheet 10 is located. The transmitted haze of the optical sheet 10 can be 10% or more, 12% or more, 20% or more, 30% or more, 31% or more, 35% or more, 40% or more, or 48% or more.

[0065] By setting an upper limit on the transmission haze of the optical plate 10, the clouding of the optical plate 10 can be suppressed. This improves the contrast of the image observed through the optical plate 10. The transmission haze of the optical plate 10 can be 70% or less, 66% or less, 60% or less, or 50% or less.

[0066] The transmission haze of the optical sheet 10 can be above 10% and below 70%, above 12% and below 70%, above 20% and below 70%, above 30% and below 70%, above 31% and below 70%, above 35% and below 70%, above 40% and below 70%, or above 48% and below 70%. The transmission haze of the optical sheet 10 can also be above 10% and below 66%, above 12% and below 66%, above 20% and below 66%, above 30% and below 66%, above 31% and below 66%, above 35% and below 66%, above 40% and below 66%, or above 48% and below 66%. The transmission haze of the optical sheet 10 can be above 10% and below 60%, above 12% and below 60%, above 20% and below 60%, above 30% and below 60%, above 31% and below 60%, above 35% and below 60%, above 40% and below 60%, or above 48% and below 60%. The transmission haze of the optical sheet 10 can also be above 10% and below 50%, above 12% and below 50%, above 20% and below 50%, above 30% and below 50%, above 31% and below 50%, above 35% and below 50%, above 40% and below 50%, or above 48% and below 50%.

[0067] The anti-glare layer 30 imparts anti-glare properties to the optical sheet 10. The anti-glare layer 30 can also diffuse at least a portion of the transmitted light to perform its anti-glare function. By adjusting the anti-glare function of the anti-glare layer 30, the transmitted haze of the optical sheet 10 can be adjusted.

[0068] The anti-glare layer 30 may include a first surface 31 and a second surface 32. The first surface 31 and the second surface 32 are opposite to each other in the first direction D1. The first surface 31 is located on the first side in the first direction D1. The second surface 32 is located on the second side in the first direction D1.

[0069] like Figure 1As shown, the anti-glare layer 30 may include a textured surface 31X. The anti-glare layer 30 can perform its anti-glare function through the textured surface 31X. The textured surface 31X may be closer to the first surface 11 than the second surface 12 in the first direction D1. The textured surface 31X may face the first side in the first direction D1. The textured surface 31X may also face the same side as the first surface 11 in the first direction D1. The textured surface 31X may also face the opposite side to the second surface 12 in the first direction D1. In the illustrated example, the first surface 31 includes the textured surface 31X. In the illustrated example, the first surface 31 is the textured surface 31X.

[0070] like Figure 1 As shown, the uneven surface 31X may include a reference portion 31A and a protrusion 31B. The protrusion 31B is a portion that protrudes from the reference portion 31A in a first direction D1. The protrusion 31B protrudes from the reference portion 31A to a first side in the first direction D1. The protrusion 31B is located on the first side in the first direction D1, closer to the reference portion 31A than the reference portion 31A. The protrusion 31B protrudes toward the first surface 11 in the first direction D1. The protrusion 31B protrudes in the first direction D1 toward a side opposite to the second surface 12. The reference portion 31A may be a flat portion extending along a surface orthogonal to the first direction D1. The reference portion 31A may also be a flat portion extending substantially along a surface orthogonal to the first direction D1. The reference portion 31A may also be a recess.

[0071] like Figure 1 As shown, the anti-glare layer 30 may comprise resin 36 and particles 37. In the illustrated example, the reference portion 31A is located in the region of the anti-glare layer 30 where particles 37 are absent when viewed from the first direction D1. Figure 1 In the example shown, the reference portion 31A is a flat portion.

[0072] The first surface 11 may include a concave-convex surface 11X. The concave-convex surface 11X may include concave and convex features corresponding to the concave and convex features of the concave-convex surface 31X. That is, the concave-convex surface 11X may include a protrusion at a position opposite to the protrusion 31B of the concave-convex surface 31X in the first direction D1. The concave-convex surface 11X may also include a reference portion that is either a flat portion or a concave portion at a position opposite to the reference portion 31A of the concave-convex surface 31X in the first direction D1.

[0073] The height difference between the convex portion of the concave-convex surface 11X and the reference portion along the first direction D1 can be the same as the height difference between the convex portion 31B of the concave-convex surface 31X and the reference portion 31A along the first direction D1. The height difference between the convex portion of the concave-convex surface 11X and the reference portion along the first direction D1 can also be less than the height difference between the convex portion 31B of the concave-convex surface 31X and the reference portion 31A along the first direction D1. The height difference between the convex portion of the concave-convex surface 11X and the reference portion along the first direction D1 can also be less than the height difference between the convex portion 31B of the concave-convex surface 31X and the reference portion 31A along the first direction D1.

[0074] like Figure 2A and Figure 2B As shown, the functional layer 40 includes an adhesive component 46 and hollow silica particles 47. Figure 2A and Figure 2B In the context of Figure 1 An enlarged view of functional layer 40 is shown in the same cross section.

[0075] Hollow silica particles 47 are low-refractive-index particles. The refractive index of hollow silica particles 47 can be lower than that of the binder component 46. Figure 1 In the example shown, functional layer 40 can be configured as a layer with a lower refractive index than anti-glare layer 30. Functional layer 40 has a reflection suppression function. Functional layer 40 can be a low-reflection layer or a reflection suppression layer with reflection suppression function. Functional layer 40 suppresses the reflection of ambient light from the environment on which the optical sheet 10 is disposed at the first surface 11. Figure 1 As shown, functional layer 40 can form the first surface 11.

[0076] like Figure 1 As shown, the thickness of the functional layer 40 can be smaller than the height difference between the reference portion 31A and the protrusion 31B. The functional layer 40 extends along the concave-convex surface 31X. The concave-convex surface 11X has concave-convex surfaces corresponding to the concave-convex surface 31X. Due to the concave-convex surfaces 11X and 31X, the optical sheet 10 can change the direction of incident light travel. The optical sheet 10 can also have a light-diffusing function that diffuses incident light due to the concave-convex surfaces 11X and 31X. The optical sheet 10 can also reflect incident light in directions other than the specular reflection direction due to the concave-convex surfaces 11X and 31X. Due to the concave-convex surfaces 11X and 31X, the optical sheet 10 can diffuse and reflect at least a portion of the incident light. Through the optical effects at the concave-convex surfaces 11X and 31X, the anti-glare layer 30 can exhibit an anti-glare function.

[0077] Based on the anti-glare and reflection suppression functions of the optical sheet 10, it is possible to suppress the reflection of background elements, such as lighting devices, into the optical sheet where it is located. By suppressing the reflection of the background, the area behind the optical sheet can be clearly observed. For example, when the optical sheet is located on the image forming surface of the display element, it is possible to suppress the overlap between the reflected image and the image formed by the display element. Therefore, the image displayed by the display element can be clearly observed.

[0078] However, tinting may be observed in optical sheets containing a functional layer with reflection suppression capabilities. Light of different wavelengths has different reflectivities at the functional layer. The reflectivity of light of the same wavelength varies depending on the thickness of the functional layer and the angle of incidence towards it. These phenomena are considered a major reason for the tinting observed in optical sheets. The inventors have confirmed that this undesirable condition of tinting becomes more pronounced in optical sheets containing both an anti-glare layer and a functional layer. Adjusting the thickness and refractive index of the functional layer has been considered as a means of suppressing tinting. However, while adjusting the thickness and refractive index of the functional layer is effective to some extent for optical sheets containing a functional layer but not an anti-glare layer, it is sometimes insufficiently effective for optical sheets containing both an anti-glare layer and a functional layer.

[0079] <<Feature A: Appropriate coordination parameters>>

[0080] The optical sheet 10 of this embodiment has the following feature (A).

[0081] (A): Based on the observation on face 11, the appropriate coordination parameters of the hollow silica particles 47 are above 1.0 and below 2.0.

[0082] The appropriate coordination parameter specified in feature (A) is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of other hollow silica particles 47 observed on the first surface 11 whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of the hollow silica particle 47 observed on the first surface 11. The inappropriate coordination number is the number of other hollow silica particles 47 observed on the first surface 11 whose centroids are located at a distance of less than 55 nm from the centroid of the hollow silica particle 47 observed on the first surface 11.

[0083] Figures 3A-3C This is an enlarged top view showing the first side 11. Figure 3A It shows Figure 2A The first surface 11 of the optical sheet 10 shown.

[0084] exist Figure 3A In the example shown, there are two other hollow silica particles 47B observed on the first surface 11, located at a distance of more than 55 nm and less than 75 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11, with the centroid 47BC being located at the same distance. Figure 3A In the example shown, the number of other hollow silica particles 47B observed on the first surface 11 at a distance of less than 55 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11 is 0. That is, in Figure 3AIn the example shown, the number of proper coordination numbers is 2, and the number of improper coordination numbers is 0. Figure 3A In the example shown, the appropriate coordination parameter is 2.

[0085] exist Figure 3B In the example shown, there are two other hollow silica particles 47B observed on the first surface 11, located at a distance of more than 55 nm and less than 75 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11, with the centroid 47BC being located at the same distance. Figure 3B In the example shown, the number of other hollow silica particles 47C observed on the first surface 11, where the centroid 47CC is located at a distance of less than 55 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11, is one. That is, in Figure 3B In the example shown, the proper coordination number is 2, and the improper coordination number is 1. Figure 3B In the example shown, the appropriate coordination parameter is 1.

[0086] exist Figure 3C In the example shown, the number of other hollow silica particles 47B observed on the first surface 11 at a distance of more than 55 nm and less than 75 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11 is 4. Figure 3C In the example shown, the number of other hollow silica particles 47C observed on the first surface 11, where the centroid 47CC is located at a distance of less than 55 nm from the centroid 47AC of a hollow silica particle 47A observed on the first surface 11, is one. That is, in Figure 3C In the example shown, the number of proper coordination numbers is 4, and the number of improper coordination numbers is 1. Figure 3C In the example shown, the appropriate coordination parameter is 3.

[0087] As demonstrated in the embodiments described later, according to feature (A), it is possible to stably suppress the hue observed in the optical sheet 10, which includes both the anti-glare layer and the functional layer.

[0088] According to feature (A), when observing the back of the optical sheet 10, it is possible to suppress changes in the hue of the image behind the optical sheet 10 due to the hue generated by the optical sheet 10. For example, when the optical sheet 10 is located on the image forming surface of the display element, it is possible to suppress changes in the hue of the image formed by the display element.

[0089] Furthermore, according to feature (A), even when the background of the optical film 10, which includes the anti-glare layer and the functional layer, is relatively dark, the tint observed in the optical film 10 can be effectively suppressed. Therefore, giving the optical film 10 a premium feel can enhance its commercial value.

[0090] The details of why feature (A) can suppress the observation of hue in optical film 10 are not yet clear, but it is speculated that the following is a major reason. However, this embodiment is not limited to the following assumption.

[0091] If the proportion of hollow silica particles in the functional layer increases, the refractive index of the functional layer decreases. If the refractive index of the functional layer decreases, the reflection suppression function of the functional layer is enhanced. Therefore, the proportion of hollow silica particles in the functional layer where reflection suppression is desired is usually relatively large.

[0092] In functional layers containing a large proportion of hollow silica particles, when the hollow silica particles are not uniformly dispersed, such as... Figure 2B As shown, the in-plane deviation of the functional layer thickness can become larger. The center wavelength of the suppressed reflection light varies depending on the thickness of the functional layer. The center wavelength of the suppressed reflection light refers to the wavelength of light with the lowest reflectivity.

[0093] Furthermore, if the hollow silica particles are not uniformly dispersed, the in-plane deviation of the local refractive index of the functional layer may also increase. The reflectivity varies depending on the refractive index of the functional layer. Therefore, the reflection suppression function of the optical sheet 10 is locally insufficient.

[0094] As described above, if the hollow silica particles are not uniformly distributed, the reflective properties of the optical sheet become non-uniform in-plane. Consequently, it is inferred that light in a portion of the wavelength range contained in ambient light, such as illumination light, may be unexpectedly reflected by the optical sheet, resulting in a tint effect due to this reflected light. The non-uniformity in the distribution of the hollow silica particles may become more pronounced in functional layers overlapping with anti-glare layers, particularly those with anti-glare layers containing uneven surfaces.

[0095] In the optical sheet 10 with feature (A), hollow silica particles 47 can be uniformly dispersed in the functional layer 40. In the functional layer 40, which contains hollow silica particles 47 in a large proportion, the hollow silica particles 47 can be regularly arranged. For example... Figure 2A and Figure 3AAs shown, the hollow silica particles 47 can be uniformly dispersed along the surface of the optical sheet 10. Furthermore, multiple layers containing uniformly dispersed hollow silica particles 47 can be stacked in the first direction D1. For example, the functional layer 40 can contain two, three, or four layers of uniformly dispersed hollow silica particles 47. That is, by satisfying feature (A), the in-plane deviation of the thickness of the functional layer 40 can be reduced. By satisfying feature (A), the in-plane deviation of the proportion of hollow silica particles 47 in the functional layer 40 is reduced. As a result, in the optical sheet 10 having feature (A), hue observation can be effectively suppressed while ensuring excellent reflection suppression and excellent anti-glare functions.

[0096] By setting an appropriate lower limit for the coordination parameter, it is possible to suppress Color system The value becomes too small. That is, by setting an appropriate lower limit for the coordination parameter, it is possible to suppress the observation of the optical plate 10 as blue.

[0097] like Figure 2B , Figure 3B As shown, if the hollow silica particles 47 are not uniformly dispersed, the appropriate coordination parameter becomes smaller. With a small appropriate coordination parameter, the thickness of the functional layer 40 may become uneven. Furthermore, the proportion of hollow silica particles 47 increases in regions with a large thickness of the functional layer 40, potentially leading to a smaller refractive index. Conversely, the proportion of hollow silica particles 47 decreases in regions with a small thickness of the functional layer 40, potentially leading to a larger refractive index. Therefore, it is speculated that the reflection suppression function for short-wavelength light such as blue light will decrease. It is believed that by setting a lower limit for the appropriate coordination parameter, it is possible to suppress the optical sheet 10 from being observed as blue.

[0098] Based on the above viewpoints, appropriate coordination parameters can be 1.0 or higher, 1.1 or higher, 1.2 or higher, 1.3 or higher, 1.4 or higher, or 1.5 or higher.

[0099] By setting an appropriate upper limit for the coordination parameter, it is possible to suppress Color system The value becomes too large. That is, by setting an appropriate upper limit for the coordination parameter, it is possible to suppress the observation of the optical plate 10 as red.

[0100] like Figure 3C As shown, if the hollow silica particles 47 are arranged closely and uniformly, the appropriate coordination parameter increases. With a large appropriate coordination parameter, the thickness of the functional layer 40 remains constant. Furthermore, the proportion of hollow silica particles 47 in the functional layer 40 can be increased. Figure 3CIn the example shown, it is speculated that the reflectivity of green light in the central wavelength region of visible light is concentratedly reduced. It is believed that by setting an upper limit on an appropriate coordination parameter, it is possible to suppress the observation of the complementary color of green, i.e., red, in optical sheet 10.

[0101] Based on the above viewpoints, the upper limit of an appropriate coordination parameter can be below 2.0, below 1.8, below 1.6, below 1.5, or below 1.4.

[0102] Suitable coordination parameters can be 1.0 or higher and below 2.0, 1.1 or higher and below 2.0, 1.2 or higher and below 2.0, 1.3 or higher and below 2.0, 1.4 or higher and below 2.0, or 1.5 or higher and below 2.0. Suitable coordination parameters can be 1.0 or higher and below 1.8, 1.1 or higher and below 1.8, 1.2 or higher and below 1.8, 1.3 or higher and below 1.8, 1.4 or higher and below 1.8, or 1.5 or higher and below 1.8. Suitable coordination parameters can be 1.0 or higher and below 1.6, 1.1 or higher and below 1.6, 1.2 or higher and below 1.6, 1.3 or higher and below 1.6, 1.4 or higher and below 1.6, or 1.5 or higher and below 1.6. Suitable coordination parameters can be 1.0 or higher and below 1.5, 1.1 or higher and below 1.5, 1.2 or higher and below 1.5, 1.3 or higher and below 1.5, or 1.4 or higher and below 1.5. Suitable coordination parameters can be 1.0 or higher and below 1.4, 1.1 or higher and below 1.4, 1.2 or higher and below 1.4, or 1.3 or higher and below 1.4.

[0103] <<Characteristic B: Standard deviation of appropriate coordination parameters>>

[0104] In addition to the feature (A) mentioned above, the optical sheet 10 may also have feature (B).

[0105] (B): The standard deviation of the appropriate coordination parameter is below 0.30.

[0106] As described below, the appropriate coordination parameter was determined to be the average of 14 average appropriate coordination parameter values. The 14 average appropriate coordination parameter values ​​were obtained by removing the maximum and minimum values ​​from the 16 average appropriate coordination parameter values ​​determined separately based on 16 images. The standard deviation of the appropriate coordination parameter is the standard deviation of the 14 average appropriate coordination parameter values ​​used to calculate the appropriate coordination parameter.

[0107] As described above, based on feature (A), the hue observed in the optical sheet 10, which includes both the anti-glare layer and the functional layer, can be stably suppressed. In addition to feature (A), by setting an upper limit on the standard deviation of the appropriate coordination parameter, the color unevenness of the optical sheet can be reduced. By decreasing the standard deviation of the appropriate coordination parameter, the in-plane color unevenness of the optical sheet can be made less noticeable.

[0108] The standard deviation of the appropriate coordination parameter can be below 0.30, below 0.25, below 0.20, below 0.19, below 0.18, below 0.16, or below 0.14.

[0109] There is no specific lower limit for the standard deviation of an appropriate coordination parameter. The standard deviation of an appropriate coordination parameter can be above 0 or greater than 0.

[0110] The standard deviation of an appropriate coordination parameter can be greater than 0 and less than 0.30, greater than 0 and less than 0.25, greater than 0 and less than 0.20, greater than 0 and less than 0.19, greater than 0 and less than 0.18, greater than 0 and less than 0.16, or greater than 0 and less than 0.14.

[0111] In combination with feature (A), by setting an upper limit on the standard deviation of an appropriate coordination parameter, it is possible to more effectively suppress [the condition]. Color system The value becomes too large. That is, by setting an upper limit on the standard deviation of the appropriate coordination parameters, it is possible to more effectively suppress the observation of the optical plate 10 as red.

[0112] The appropriate coordination parameters and their standard deviation can be adjusted by the proportion of solid components in the functional layer forming coating liquid used to form the functional layer 40, the drying conditions of the coating film of the functional layer forming coating liquid, the content of hollow silica particles 47 in the functional layer 40, the average thickness of the functional layer 40, and the average particle size of the hollow silica particles 47. For example, increasing the content of hollow silica particles 47 in the functional layer 40 tends to increase the appropriate coordination parameters. Decreasing the content of hollow silica particles 47 in the functional layer 40 tends to decrease the appropriate coordination parameters. Increasing the average thickness of the functional layer 40 tends to decrease the appropriate coordination parameters. Decreasing the average thickness of the functional layer 40 tends to increase the appropriate coordination parameters. Decreasing the average particle size of the hollow silica particles 47 tends to increase the appropriate coordination parameters.

[0113] By adjusting one or more of the following factors—the average thickness of the functional layer 40, the proportion of hollow silica particles 47 in the functional layer 40, and the average particle size of the hollow silica particles 47—the standard deviation of the appropriate coordination parameter can be adjusted. By ensuring that the functional layer 40 of appropriate volume contains a suitable total volume of hollow silica particles 47, the standard deviation of the appropriate coordination parameter can be reduced.

[0114] Regarding optical plate 10 Color system Value and The value is measured using reflected light with the first surface 11 as the incident surface. A black plate is attached to the surface of the sample, which is composed of the second surface of the optical sheet, using an optically transparent adhesive. The black plate is a Kuraray "COMOGLASS K, color number: 502K (thickness 2mm)". The surface of the evaluation sample, which is composed of the first surface 11 of the optical sheet 10, is illuminated with light at an incident angle of 8°. Using a 2-degree field of view, the reflectance is calculated based on measurements taken at 10nm intervals in the range of 400nm to 700nm. Color system Value and Value. In Value and The D65 light source was used in the measurement of the value. Value and Before measuring the value, turn on the light source of the measuring device for 15 minutes to allow the light source output to stabilize. Measurement Value and The incident surface at the time of measurement is the first surface 11 of the optical plate 10. Measurement Value and The test environment was set at a temperature of 23℃±2℃ and a relative humidity of 50%±5%. The samples were prepared in the test environment for 16 hours before the test began.

[0115] The value is the arithmetic mean of five measurements. The five relevant measurements are set as measurements taken at five locations on the sample. The five measurement locations are located at least 10 mm apart. The value is the arithmetic mean of five measurements. Five measurements related to the value were set up at the point where the value was measured. The values ​​were measured at five locations for five different values.

[0116] <Methods for determining the standard deviation of appropriate coordination parameters, appropriate coordination numbers, inappropriate coordination numbers, and appropriate coordination parameters>

[0117] The appropriate coordination parameter is obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate and inappropriate coordination numbers are determined by the following steps. The steps for determining the appropriate and inappropriate coordination numbers include: acquiring an observation image of the first surface 11; determining the centroid of the hollow silica particles 47 based on the observation image; and determining the appropriate and inappropriate coordination numbers based on the centroid of each hollow silica particle 47.

[0118] (Steps to obtain the observation image of the first side)

[0119] A 5mm × 5mm sample is cut from the optical slide 10, which is to be evaluated. Conductive double-sided tape is applied to the entire area of ​​the sample surface corresponding to the second side 12 of the optical slide 10. Then, the conductive double-sided tape attached to the sample is attached to a flat sample stage. Thus, the sample is fixed to the flat sample stage using conductive double-sided tape. The flat sample stage is an accessory of a scanning electron microscope (SEM) used for sample observation. The conductive double-sided tape is not particularly limited. The conductive double-sided tape can be a carbon ribbon for SEM using an aluminum substrate manufactured by Nisshin EM Co., Ltd.

[0120] Carbon paste is applied to the four corners of the sample, which is fixed to the flat sample stage. The carbon paste is not particularly limited. It can be colloidal graphite No. 7141 manufactured by Nisshin EM Co., Ltd. (solvent: isopropanol).

[0121] Next, a PtPd vapor-deposited film was formed on the sample using an ion sputtering apparatus. The ion sputtering conditions were as follows: Ar gas was introduced into the chamber containing the sample.

[0122] Target: PtPd

[0123] Vacuum degree: 8Pa

[0124] • Discharge current value: 15mA

[0125] Evaporation time: 15 seconds

[0126] After the vapor-deposited film is formed, a standard sample stage with the sample fixed on it is mounted on the standard sample holder of a scanning electron microscope. The observation conditions of the scanning electron microscope are as follows: an observation image of the sample surface corresponding to the first surface 11 of the optical slide 10, which is the object of evaluation, is acquired. The scanning electron microscope used is a Hitachi High-Tech SU-9000 ultra-high resolution field emission scanning electron microscope. Figure 4A An example of an image being observed is shown magnified.

[0127] • Measurement mode: SE

[0128] Accelerating voltage: 1.0kV

[0129] • Transmit current: 10μA

[0130] • WD (working distance): 3mm or more and 3.5mm or less

[0131] Lens mode: High

[0132] • Observation magnification: 10,000x

[0133] • Data size: 1280 pixels × 960 pixels

[0134] • Pixel Size: 3.96875nm

[0135] Sixteen observation images were obtained through the above steps. These observation images were obtained by photographing each of the 16 rectangular partitioned regions, which were obtained by dividing the rectangular measurement area in the sample into four equal parts in both the longitudinal and transverse directions.

[0136] (Steps for determining the center of gravity of hollow silica particles 47 based on observed images)

[0137] From the observed images obtained above, only unnecessary parts such as scale bars are removed, except for the images used as samples. By deleting unnecessary parts, image data for image processing is obtained. Since one image data point is obtained from each observed image, a total of 16 image data points are obtained.

[0138] Next, the image data is binarized. Through binarization, the bright areas of the image data become white areas, and the dark areas become black areas. This results in an image with circular white areas scattered within a black background. The white areas appear at the locations of the hollow silica particles 47. Since one binarized image data is obtained from each image data, a total of 16 binarized image data are obtained.

[0139] In the binarization process, ImageJ and Fiji are used as image processing software. ImageJ version 1.52e is used. ImageJ is an open-source, public domain image processing software developed by the National Institutes of Health. Fiji is a plugin package for ImageJ. The following commands in Fiji are used for binarization. Under the following conditions, the white portion is independently generated for each hollow silica particle 47 observed independently in the microscope image. Figure 4B Showing the Figure 4AThe image is after binarization. In the command "AutoLocal Threshold", "Metod=Median" means that the median value of the local grayscale distribution is selected as the threshold. "Radius=60" means that the radius of the local area for threshold calculation is 60 pixels. "Parameter=-25" is a parameter for adjusting the threshold, meaning that the value obtained by subtracting "-25" from the selected threshold is used as the threshold value.

[0140] Enlarge the dimensions by 2.5 times.

[0141] Noise Removal: Despeckle

[0142] • Binarization: Automatic region thresholding (Metod=Median, Radius=60, Parameter=-25)

[0143] • Separation of the white portion: Watershed

[0144] Noise Removal: Open

[0145] By processing the binarized image data, the coordinates representing the centroid positions of each white portion of the hollow silica particles 47 are determined. A binary image is generated, with one pixel located at the centroid of each white portion set to white and the other pixels set to a black background. One binary image is obtained from each binarized image data, resulting in a total of 16 binary images. Additionally, the centroid coordinates of the hollow silica particles 47 are obtained. Fiji's Analyse Perticles function is used in the generation of the binary images. Figure 4C Based on Figure 4B The binary image generated from the image.

[0146] (The procedure for determining the appropriate and inappropriate coordination numbers from the center of gravity of each hollow silica particle 47)

[0147] Each hollow silica particle 47 contained in the binary image is treated as a single hollow silica particle 47A, and the appropriate and inappropriate coordination numbers are determined. For all hollow silica particles 47 contained in the binary image, the appropriate and inappropriate coordination numbers are determined. For all hollow silica particles 47 contained in the binary image, the appropriate coordination parameter is calculated from the results of the appropriate and inappropriate coordination number determinations.

[0148] Specifically, for each particle identified in the binary image, the distances between the centroid coordinates of that particle and the centroid coordinates of other particles located nearby are listed. Then, by counting the number of particles from the resulting list, the values ​​of the appropriate coordination number, inappropriate coordination number, and appropriate coordination parameter for that particle are obtained.

[0149] The arithmetic mean of the appropriate coordination parameters measured for each hollow silica particle 47 contained in the binary image as a hollow silica particle 47A is set as the average appropriate coordination parameter value for the binary image. By removing the maximum and minimum values ​​from the 16 average appropriate coordination parameter values ​​calculated for each of the 16 binary images, 14 average appropriate coordination parameter values ​​are obtained. The arithmetic mean of the 14 average appropriate coordination parameter values ​​is taken as the appropriate coordination parameter of the optical sheet 10. The optical sheet 10 is evaluated based on whether the calculated appropriate coordination parameter of the optical sheet 10 satisfies the conditions specified in feature (A).

[0150] The standard deviation of the 14 average values ​​of the appropriate coordination parameters used to calculate the appropriate coordination parameters is taken as the standard deviation of the appropriate coordination parameters of the optical sheet 10. The optical sheet 10 is evaluated based on whether the calculated standard deviation of the appropriate coordination parameters of the optical sheet 10 meets the conditions specified in feature (B).

[0151] Furthermore, a radial distribution function can be generated by summarizing the data on the distance between the centroids of all particles contained in the binary image. The inventors investigated the radial distribution function related to the distance between the centroids of the hollow silica particles contained in the functional layer for various optical sheets, and observed the arrangement of the hollow silica within the functional layer. In the functional layers of optical sheets where the peak value of the radial distribution function is 55 nm or higher and less than 75 nm, there is a tendency for the hollow silica to be arranged in a regular pattern.

[0152] It should be noted that the determination of whether feature (A) is satisfied is based on an observation image obtained from any measurement area of ​​the sample in the optical sheet 10. Appropriate coordination parameters measured using observation images obtained from any measurement area of ​​the optical sheet 10 satisfy feature (A), thereby sufficiently suppressing the hue observed in the optical sheet 10.

[0153] As described above, the anti-glare layer 30 may include a concave-convex surface 31X. The thin functional layer 40 formed on the concave-convex surface 31X of the anti-glare layer 30 may have different thicknesses depending on the reference portion 31A and the protrusion 31B in the concave-convex surface 31X of the anti-glare layer 30. That is, the thickness of the functional layer on the reference portion 31A may be different from the thickness of the functional layer on the protrusion 31B. The thickness of the functional layer on the reference portion 31A may be thicker than the thickness of the functional layer on the protrusion 31B. Meanwhile, the arrangement of the hollow silica particles 47 may also differ between the functional layer 40 located on the reference portion 31A and the functional layer 40 located on the protrusion 31B. However, by managing the optical sheet 10 with appropriate alignment parameters, the generation of hue in the optical sheet 10 can be suppressed. In other words, by managing it with appropriate alignment parameters, an optical sheet 10 including the anti-glare layer 30 and the functional layer 40 can be obtained, suppressing the generation of hue.

[0154] The appropriate coordination parameter can be a value measured in the region of the first surface 11 that is opposite to the reference part 31A in the first direction D1. The appropriate coordination parameter measured in the region of the first surface 11 that is opposite to the reference part 31A in the first direction D1 refers to the appropriate coordination parameter obtained by measuring 16 observation images obtained from a measurement region containing only the reference part 31A or a measurement region centered on the reference part 31A. The appropriate coordination parameter measured based on the hollow silica particles 47 observed in the region of the first surface 11 that is opposite to the reference part 31A in the first direction D1 satisfies characteristic (A), thereby stably suppressing the hue observed in the optical sheet 10.

[0155] The appropriate coordination parameter can also be a value measured in the region of the first surface 11 opposite to the region of the anti-glare layer 30 where particles 37 are absent in the first direction D1. The appropriate coordination parameter measured in the region of the first surface 11 opposite to the region of the anti-glare layer 30 where particles 37 are absent refers to the appropriate coordination parameter measured using 16 observation images obtained from a measurement region containing only the region where particles 37 are absent or a measurement region centered on the region where particles 37 are absent. The appropriate coordination parameter measured based on the hollow silica particles 47 observed in the region of the first surface 11 opposite to the region of the anti-glare layer 30 where particles 37 are absent satisfies feature (A) and can stably suppress the hue observed in the optical sheet 10.

[0156] << Color system Value and Value >>

[0157] Regarding optical plate 10 Color system Value and The value can be within the specified range. The value can be above -4.0 and below 4.0. The value can be above -4.0 and below 4.0. By making... Value and When the value is within the specified range, it can effectively suppress the perceived hue on the optical film 10. Color system Value and The value is determined by using reflected light with the first surface 11 as the incident surface through the above method.

[0158] Through the Color system Setting a lower limit for the value can suppress the observation of the optical sheet 10 appearing green. Color system The value can be above -4.0, above -3.0, above -2.0, above -1.0, or above 0.

[0159] Through the Color system Setting an upper limit for the value can suppress the observation of the optical plate 10 appearing red. Color system The value can be below 4.0, below 3.6, below 3.5, below 3.0, or below 2.9.

[0160] Color system The value can be above -4.0 and below 4.0, above -3.0 and below 4.0, above -2.0 and below 4.0, above -1.0 and below 4.0, or above 0 and below 4.0. Color system The value can be above -4.0 and below 3.6, above -3.0 and below 3.6, above -2.0 and below 3.6, above -1.0 and below 3.6, or above 0 and below 3.6. Color system The value can be above -4.0 and below 3.5, above -3.0 and below 3.5, above -2.0 and below 3.5, above -1.0 and below 3.5, or above 0 and below 3.5. Color system The value can be above -4.0 and below 3.0, above -3.0 and below 3.0, above -2.0 and below 3.0, above -1.0 and below 3.0, or above 0 and below 3.0. Color system The value can be above -4.0 and below 2.9, above -3.0 and below 2.9, above -2.0 and below 2.9, above -1.0 and below 2.9, or above 0 and below 2.9.

[0161] Through the Color system Setting a lower limit for the value can suppress the blue color of the optical plate 10 from being observed. Color system The value can be above -4.0, above -3.0, above -2.5, above -2.0, or above -1.7.

[0162] Through the Color system Setting an upper limit for the value can suppress the yellowing of the optical plate 10 from being observed. Color system The value can be below 4.0, below 3.0, below 2.0, below 1.0, or below 0.

[0163] Color system The value can be above -4.0 and below 4.0, above -3.0 and below 4.0, above -2.5 and below 4.0, above -2.0 and below 4.0, or above -1.7 and below 4.0. Color system The value can be above -4.0 and below 3.0, above -3.0 and below 3.0, above -2.5 and below 3.0, above -2.0 and below 3.0, or above -1.7 and below 3.0. Color system The value can be above -4.0 and below 2.0, above -3.0 and below 2.0, above -2.5 and below 2.0, above -2.0 and below 2.0, or above -1.7 and below 2.0. Color system The value can be above -4.0 and below 1.0, above -3.0 and below 1.0, above -2.5 and below 1.0, above -2.0 and below 1.0, or above -1.7 and below 1.0. Color system The value can be above -4.0 and below 0, above -3.0 and below 0, above -2.5 and below 0, above -2.0 and below 0, or above -1.7 and below 0.

[0164] By making Color system Value and When the value is within the aforementioned specified range, the hue observed on the optical sheet 10 can be effectively suppressed. When viewing the back of the optical sheet 10, the hue of the image behind the optical sheet 10 can be suppressed from changing due to the hue generated by the optical sheet 10. For example, when the optical sheet 10 is located on the image forming surface of the display element, changes in the hue of the image formed by the display element can be suppressed.

[0165] By making Color system Value and Within the aforementioned specified range, even in dark conditions behind the optical film 10, which includes both anti-glare and functional layers, the tint observed on the optical film 10 can be effectively suppressed. Therefore, giving the optical film 10 a premium feel can enhance its commercial value.

[0166] Total transmittance

[0167] The total light transmittance of the optical sheet 10 can be above 50%, above 70%, above 80%, or above 90%. There is no specific upper limit to the total light transmittance of the optical sheet 10. The total light transmittance of the optical sheet 10 can also be below 100% or less than 100%.

[0168] The total light transmittance of the optical sheet 10 can be above 50% and below 100%, above 70% and below 100%, above 80% and below 100%, or above 90% and below 100%. Alternatively, the total light transmittance of the optical sheet 10 can be above 50% and below 100%, above 70% and below 100%, above 80% and below 100%, or above 90% and below 100%.

[0169] The total transmittance was measured using a D65 light source. Before measuring the total transmittance, the D65 light source was lit for 15 minutes to stabilize its output. The incident angle of the sample was set to 0° during the total transmittance measurement. The incident surface for measuring the total transmittance of the optical plate 10 was the second surface 12 of the optical plate 10. The test environment for measuring the total transmittance was set to a temperature of 23℃±2℃ and a relative humidity of 50%±5%. The sample was placed in the test environment for 16 hours before the test. Other measurement conditions for the total transmittance were in accordance with JIS K7361-1:1997.

[0170] The total transmittance was set as the arithmetic mean of five measurements. These five measurements were taken at five locations on the sample, spaced at least 10 mm apart.

[0171] <<Visual Reflectivity>>

[0172] The visual reflectance of the optical sheet 10 can be below 2.0%, below 1.5%, below 1.4%, or below 1.2%. There is no particular lower limit to the visual reflectance of the optical sheet 10. The visual reflectance of the optical sheet 10 can be above 0% or greater than 0%.

[0173] The visual reflectance of the optical sheet 10 can be above 0% and below 2.0%, above 0% and below 1.5%, above 0% and below 1.4%, or above 0% and below 1.2%. The visual reflectance of the optical sheet 10 can also be greater than 0% and below 2.0%, greater than 0% and below 1.5%, greater than 0% and below 1.4%, or greater than 0% and below 1.2%.

[0174] Visual reflectance is the Y value of the tristimulus values ​​XYZ in the CIE 1931 standard colorimetric system. Visual reflectance is SCI, which includes positively reflected light. Visual reflectance (%) is measured using a spectrophotometer as follows.

[0175] A sample is cut from the optical sheet 10, which is to be evaluated. The sample is visually confirmed to be free of dust, scratches, or other abnormalities. A black plate is attached to the surface of the sample, which is formed by the second side of the optical sheet, using an optically transparent adhesive. The total light transmittance of the black plate is less than 1%. Through the above operations, an evaluation sample A, consisting of an optical sheet, an optically transparent adhesive layer, and a black plate, is prepared.

[0176] The surface of evaluation sample A, which is composed of the first surface of the optical sheet, is illuminated with light at an incident angle of 8°. The apparent reflectance of evaluation sample A is measured based on the total internal reflection. Using a 2-degree field of view, the apparent reflectance (%) is calculated based on reflectance measured at 10 nm intervals in the range from 400 nm to 700 nm. A D65 light source is used for the measurement of apparent reflectance (%). Before measuring the apparent reflectance of optical sheet 10, the light source of the measuring instrument is lit for 15 minutes to allow the light source output to stabilize. The test environment for measuring apparent reflectance is set to a temperature of 23℃ ± 2℃ and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before the start of the test.

[0177] Other measurement conditions for determining visual reflectance shall be in accordance with JIS Z 8722:2009. The geometric conditions in JIS Z 8722:2009 shall be set as condition c, which includes specular reflection components.

[0178] The visual reflectance was set as the arithmetic mean of five measurements. These five measurements were taken at five locations on the sample, spaced at least 10 mm apart.

[0179] <<Visual reflectance and color coordinates The product of values, and the relationship between visual reflectance and color coordinates Product of values ​​>>

[0180] From the viewpoint of more effectively suppressing the generation of hues, the optical film 10 can satisfy the following characteristics (x) and characteristics (y).

[0181] Feature (x): The apparent reflectance on the first surface 11 and the reflectance measured using the reflected light from the first surface 11. Color system The absolute value of the product of values ​​is less than 4.0.

[0182] Feature (y): The apparent reflectance on the first surface 11 and the reflectance measured using the reflected light from the first surface 11. Color system The absolute value of the product of values ​​is less than 4.0.

[0183] The visual reflectance used in the calculation of the absolute value specified by feature (x) and feature (y) is a value with the unit set to "%".

[0184] Even if it can reduce The absolute value of the value, when the visual reflectance is high, will also result in a hue that can be observed in the optical film 10. Even if the visual reflectance can be reduced, if If the absolute value of the value is large, the hue will also be observed in the optical film 10. This is achieved by comparing the visual reflectance defined by feature (x) with... Color system Setting an upper limit on the absolute value of the product of values ​​can more effectively suppress the hue observed in the optical film 10. In particular, based on feature (x), it can more effectively suppress the observation of red or green on the optical film 10.

[0185] Visual reflectance and Color system The absolute value of the product of values ​​can be below 4.0, below 3.7, below 3.5, or below 3.4. Visual reflectance and Color system The lower limit of the absolute value of the product of values ​​is not specifically defined. Visual reflectance and Color system The absolute value of the product of values ​​can be greater than or equal to 0.

[0186] Visual reflectance and Color system The absolute value of the product of values ​​can be greater than or equal to 0 and less than 4.0, greater than or equal to 0 and less than 3.7, greater than or equal to 0 and less than 3.5, or greater than or equal to 0 and less than 3.4. Visual reflectance and Color system The absolute value of the product of values ​​can be greater than 0 and less than 4.0, greater than 0 and less than 3.7, greater than 0 and less than 3.5, or greater than 0 and less than 3.4.

[0187] Even if it can reduce The absolute value of the value, when the visual reflectance is high, will also be observed in the hue in the optical film 10. Even if the visual reflectance can be reduced, if A large absolute value will also result in a hue being observed in the optical film 10. This is achieved by comparing the visual reflectance defined by the feature (y) with... Color system Setting an upper limit on the absolute value of the product of values ​​can more effectively suppress the hue observed in the optical film 10. In particular, it can more effectively suppress the observation of blue or yellow on the optical film 10, depending on the characteristic (y).

[0188] Visual reflectance and Color system The absolute value of the product of values ​​can be below 4.0, below 3.0, below 2.8, below 2.5, below 2.0, or below 1.7. Visual reflectance and Color system The lower limit of the absolute value of the product of values ​​is not specifically defined. Visual reflectance and Color system The absolute value of the product of values ​​can be greater than or equal to 0.

[0189] Visual reflectance and Color system The absolute value of the product of values ​​can be greater than or equal to 0 and less than 4.0, greater than or equal to 0 and less than 3.0, greater than or equal to 0 and less than 2.8, greater than or equal to 0 and less than 2.5, greater than or equal to 0 and less than 2.0, or greater than or equal to 0 and less than 1.7. Visual reflectance and Color system The absolute value of the product of values ​​can be greater than 0 and less than 4.0, greater than 0 and less than 3.0, greater than 0 and less than 2.8, greater than 0 and less than 2.5, greater than 0 and less than 2.0, or greater than 0 and less than 1.7.

[0190] <<Layers contained in an optical sheet>>>

[0191] Referring to the optical sheet 10 shown in the figure, the layers comprising the optical sheet 10 will be described in further detail. Figure 1 The optical sheet 10 shown includes a substrate 20, an anti-glare layer 30, and a functional layer 40 sequentially from the second surface 12 on the first direction D1 toward the first surface 11.

[0192] The optical sheet 10 may also contain other layers. Figure 5 In the example shown, the optical sheet 10, from the second surface 12 towards the first surface 11, sequentially comprises a substrate 20, an anti-glare layer 30, a second functional layer 50, and a functional layer 40. The second functional layer 50 may contain an adhesive component and particles. The particles may be high-refractive-index particles. The refractive index of the particles may be higher than that of the adhesive component. Figure 5 In the example shown, functional layer 40 can be configured as a layer with a refractive index lower than that of the second functional layer 50. The second functional layer 50 can also be configured as a layer with a refractive index higher than that of the anti-glare layer 30. Functional layer 40 and second functional layer 50 perform reflection suppression functions. Functional layer 40 and second functional layer 50 can constitute a low-reflection layer or a reflection suppression layer with reflection suppression functions.

[0193] exist Figure 1 and Figure 5 In the example shown, the first surface 11 is composed of a functional layer 40. Functional layer 40 and the second functional layer 50 are thinner layers and extend along the uneven surface 31X of the anti-glare layer 30. Figure 1 and Figure 5 In the example shown, the first surface 11 is a surface 11X with irregularities corresponding to the irregularities 31X of the anti-glare layer 30. Figure 1 and Figure 5 In the example shown, the second surface 12 is made of substrate 20.

[0194] The layers included in the optical sheet 10 may also function as other functional layers. The optical sheet 10 may also include other functional layers, unlike the example shown. Examples of other functional layers include an anti-fouling layer, a hard coating layer, and an antistatic layer.

[0195] In the illustrated example, the first direction D1 is the stacking direction. The layers 20, 30, 40, and 50 comprising the optical sheet 10 are stacked along the first direction D1. Each layer 20, 30, 40, and 50 has a normal direction parallel to the first direction D1. Each layer 20, 30, 40, and 50 extends along the second direction D2 and the third direction D3, which are orthogonal to the first direction D1. In the illustrated example, the second direction D2 and the third direction D3 are mutually orthogonal.

[0196] The following describes the substrate 20, the anti-glare layer 30, the functional layer 40, and the second functional layer 50.

[0197] <Substrate>

[0198] The substrate 20 supports the anti-glare layer 30 and the functional layer 40. For example... Figure 1 and Figure 5 As shown, the substrate 20 can form the second surface 12 of the optical sheet 10. The second surface 12 can be a flat surface. The second surface 12 can be a surface orthogonal to the first direction D1.

[0199] The substrate 20 can be transparent. Transparency means that the total light transmittance is 50% or more, which can be 70% or more, 80% or more, or 90% or more.

[0200] The material of the substrate 20 is not particularly limited; it can be resin or glass. Resin is preferred due to its lightweight and ease of manufacture.

[0201] The resin used in the substrate 20 can be a polyolefin resin such as polyethylene or polypropylene. The resin used in the substrate 20 can be a vinyl resin such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, or ethylene-vinyl alcohol copolymer. The resin used in the substrate 20 can also be a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate. The resin used in the substrate 20 can also be an acrylic resin such as poly(methyl methacrylate) or poly(ethyl methacrylate). The resin used in the substrate 20 can be a styrene resin such as polystyrene, a polyamide resin such as nylon 6 or nylon 66, or a cellulose resin such as triacetyl cellulose. Examples of resins used in the substrate 20 include cyclic olefin resins obtained from resins such as polycarbonate, polyimide resins, norbornene, dicyclopentadiene, etc. The anti-glare layer 30 may contain only one of the above-mentioned resins, or it may contain two or more of the above-mentioned resins.

[0202] Substrates containing polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PAN) can be stretched. Stretching can be uniaxial or biaxial. Stretched substrates containing polyester resins exhibit birefringence. The retarding (Re) of stretched substrates containing polyester resins can be adjusted.

[0203] The thickness of the resin substrate 20 is not particularly limited. From a processability point of view, the thickness of the resin substrate 20 can be 10 μm or more, 20 μm or more, or 50 μm or more. The thickness of the resin substrate 20 can be 500 μm or less, 400 μm or less, or 300 μm or less. The thickness of the glass substrate 20 can be 500 μm or more. The thickness of the glass substrate 20 can be 5 mm or less.

[0204] When the optical sheet 10 is used in foldable applications, the substrate 20 can also be flexible. In this example, the thickness of the resin substrate 20 can be 10 μm or more but less than 40 μm. When the optical sheet 10 is used in a glass laminate, from the perspective of preventing glass scattering, the thickness of the resin substrate 20 can also be 40 μm or more but less than 100 μm.

[0205] The substrate 20 may contain only a single layer or multiple layers. The substrate 20 may also contain an undercoat such as an easy-to-adhere layer.

[0206] <Functional Layer>

[0207] Functional layer 40 includes binder component 46 and hollow silica particles 47. Functional layer 40 may also include particles other than hollow silica particles 47. Functional layer 40 reduces its refractive index by including hollow silica particles 47. Functional layer 40 may also have a lower refractive index than binder component 46. The refractive index of functional layer 40 may be lower than the refractive index of anti-glare layer 30. The refractive index of functional layer 40 may be lower than the refractive index of layers adjacent to functional layer 40.

[0208] Functional layer 40 has a reflection suppression function that suppresses the reflection of incident light due to its refractive index and thickness. The reflection suppression function of functional layer 40 is based on the interference of light reflected from the surfaces on both sides of functional layer 40. From the viewpoint that this reflection suppression function is effective, the refractive index of functional layer 40 can also be the magnitude between the refractive indices of two regions adjacent to functional layer 40 on both sides. In the illustrated example, the refractive index of functional layer 40 can be greater than the refractive index of air and less than the refractive index of anti-glare layer 30. The thickness (nm) of functional layer 40 can be about 1 / 4 of the wavelength λ (nm) of the light to be suppressed.

[0209] From the perspective of reflection suppression, the refractive index and average thickness of the functional layer can be set as follows: The refractive index of the functional layer can be 1.10 or higher, 1.20 or higher, 1.26 or higher, 1.28 or higher, or 1.30 or higher. The refractive index of the functional layer can be 1.48 or lower, 1.45 or lower, 1.40 or lower, 1.38 or lower, or 1.35 or lower. The refractive index used for the constituent elements of the optical sheet 10 is the refractive index with a wavelength of 589.3 nm.

[0210] The thickness of the functional layer can be above 80nm, above 85nm, or above 90nm. The thickness of the functional layer can be below 150nm, below 140nm, below 130nm, below 120nm, below 110nm, or below 105nm.

[0211] The thickness of the functional layer can be above 80nm and below 150nm, above 85nm and below 150nm, or above 90nm and below 150nm. The thickness of the functional layer can be above 80nm and below 140nm, above 85nm and below 140nm, or above 90nm and below 140nm. The thickness of the functional layer can be above 80nm and below 130nm, above 85nm and below 130nm, or above 90nm and below 130nm. The thickness of the functional layer can be above 80nm and below 120nm, above 85nm and below 120nm, or above 90nm and below 120nm. The thickness of the functional layer can be above 80nm and below 110nm, above 85nm and below 110nm, or above 90nm and below 110nm. The thickness of the functional layer can be above 80nm and below 105nm, above 85nm and below 105nm, or above 90nm and below 105nm.

[0212] (Adhesive components)

[0213] The binder component 46 is an element that retains the hollow silica particles 47. The binder component 46 can also function as a binder for forming a coating film. By retaining the particles contained in the functional layer 40 through the binder component 46, the functional layer 40 can maintain its film morphology. The binder component 46 may contain a resin. The resin contained in the binder component 46 can be a natural resin or a synthetic resin. The binder component 46 can encapsulate the particles contained in the functional layer 40. The hollow silica particles 47 can either completely surround each particle contained in the functional layer 40, or at least some of the particles contained in the functional layer 40 can be partially exposed.

[0214] The adhesive component 46 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 adhesive component 46 may contain at least one of a cured thermosetting resin composition and a cured product of an ionizing radiation-curable resin composition. The cured resin can impart high strength and high hardness to the functional layer 40, improving the scratch resistance of the first surface 11. From the viewpoint of improving scratch resistance, ionizing radiation-curable resin compositions are particularly useful.

[0215] The thermosetting resin composition contains a thermosetting resin. The thermosetting resin composition is cured by heating. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. The thermosetting resin composition may also contain a curing agent.

[0216] The ionizing radiation-curable resin composition contains an ionizing radiation-curable compound. The ionizing radiation-curable compound contains an ionizing radiation-curable functional group. Examples of ionizing radiation-curable functional groups include olefinic unsaturated groups such as (meth)acryloyl, vinyl, and allyl, as well as epoxy and oxetyl groups. The ionizing radiation-curable compound may contain two or more ionizing radiation-curable functional groups. The ionizing radiation-curable compound may also be a compound having olefinic unsaturated groups. The ionizing radiation-curable compound may also be a (meth)acrylate compound having a (meth)acryloyl group. The ionizing radiation-curable compound may also be a siloxane compound containing a siloxane bond.

[0217] (Meth)acrylate compounds having four or more olefinic unsaturated groups are called "polyfunctional (meth)acrylate compounds". (Meth)acrylate compounds having two to three olefinic unsaturated groups are called "low-functional (meth)acrylate compounds".

[0218] (Meth)acrylate compounds can be monomers or oligomers. Ionizing radiation-curable compounds containing low-functionality (meth)acrylate compounds can suppress uneven shrinkage during curing, thus smoothing the surface of the functional layer 40.

[0219] The weight-average molecular weight of monomers can be greater than 0 and less than 1000, greater than 0 and less than 800, or greater than 0 and less than 600. The weight-average molecular weight of oligomers can be greater than 1500 and less than 20000, greater than 2000 and less than 15000, or greater than 3000 and less than 12000. The weight-average molecular weight is determined by GPC analysis and is the average molecular weight converted from standard polystyrene.

[0220] Ionizing rays can be electromagnetic waves or beams of charged particles. Ionizing rays possess energy quanta capable of causing molecules to aggregate or cross-link. Examples of ionizing rays include ultraviolet (UV), electron beams (EB), X-rays, gamma rays, alpha rays, and ionizing rays.

[0221] The proportion of low-functional (meth)acrylate compounds in the ionizing radiation curable compound can be 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass. From the perspective of suppressing uneven shrinkage during curing and smoothing the surface irregularity of the functional layer 40, the low-functional (meth)acrylate compound can also be a (meth)acrylate compound containing two olefinic unsaturated bond groups. When the ionizing radiation curable compound contains a large amount of polyfunctional (meth)acrylate compounds, as described later, the surface of the functional layer can be smoothed by appropriately adjusting the type of solvent and drying conditions.

[0222] Examples of difunctional (meth)acrylate compounds include dimethacrylate isocyanurate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polybutylene glycol dimethacrylate, and other polyalkylene glycol dimethacrylates, bisphenol A tetraethoxydimethacrylate, bisphenol A tetrapropoxydimethacrylate, and 1,6-hexanediol dimethacrylate. Examples of trifunctional (meth)acrylate compounds include trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, and isocyanuric acid-modified trimethacrylate. Examples of polyfunctional (meth)acrylate compounds with four or more functions include pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, and dipentaerythritol tetramethacrylate. (Meth)acrylate compounds can be modified as described below.

[0223] Examples of (meth)acrylate oligomers include urethane (meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and other acrylate polymers. Uramate (meth)acrylates are obtained, for example, by reacting a polyol and an organic diisocyanate with a hydroxyl (meth)acrylate. Epoxy (meth)acrylates can also be obtained by reacting a trifunctional or higher aromatic epoxy resin, alicyclic epoxy resin, or aliphatic epoxy resin with (meth)acrylic acid. Epoxy (meth)acrylates can also be obtained by reacting a difunctional or higher aromatic epoxy resin, alicyclic epoxy resin, or aliphatic epoxy resin with a polybasic acid and (meth)acrylic acid. Epoxy (meth)acrylates can also be obtained by reacting a difunctional or higher aromatic epoxy resin, alicyclic epoxy resin, or aliphatic epoxy resin with a phenol and (meth)acrylic acid.

[0224] From the perspective of suppressing uneven shrinkage caused by crosslinking, (meth)acrylate compounds can modify a portion of their molecular backbone. For example, (meth)acrylate compounds can be modified using ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl groups, cyclic alkyl groups, aromatic groups, bisphenols, etc. These (meth)acrylate compounds can also be modified using epoxides such as ethylene oxide and propylene oxide. The proportion of epoxide-modified (meth)acrylate compounds in ionizing radiation-curable compounds can be 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass. Epoxide-modified (meth)acrylate compounds can be low-functionality (meth)acrylate compounds or (meth)acrylate compounds having two olefinic unsaturated bond groups.

[0225] Examples of methacrylate compounds modified with alkylene oxide and having two olefinically unsaturated groups include bisphenol F alkylene oxide-modified di(meth)acrylate, bisphenol A alkylene oxide-modified di(meth)acrylate, isocyanuric acid alkylene oxide-modified di(meth)acrylate, and polyalkylene glycol di(meth)acrylate. The average repeating unit of the alkylene glycol in the polyalkylene glycol di(meth)acrylate can be 3 to 5. The alkylene glycol in the polyalkylene glycol di(meth)acrylate can be ethylene glycol and / or polyethylene glycol. Examples of methacrylate compounds modified with alkylene oxide and having three olefinically unsaturated groups include trimethylolpropane alkylene oxide-modified tri(meth)acrylate and isocyanuric acid alkylene oxide-modified tri(meth)acrylate.

[0226] Examples of siloxane compounds include (poly)dimethylsiloxane, (poly)diethylsiloxane, (poly)diphenylsiloxane, (poly)methylphenylsiloxane, alkyl-modified (poly)dimethylsiloxane, azo-containing (poly)dimethylsiloxane, dimethylsiloxane, phenylmethylsiloxane, alkyl-aralkyl-modified silicone, fluorosiloxane, polyether-modified silicone, fatty acid ester-modified silicone, methylhydrosiloxane, silanol-containing silicone, alkoxy-containing silicone, phenol-containing silicone, methacrylic acid-modified silicone, acrylic acid-modified silicone, amino-modified silicone, carboxylic acid-modified silicone, methanol-modified silicone, epoxy-modified silicone, mercapto-modified silicone, fluorinated silicone, and polyether-modified silicone.

[0227] The binder component 46 may contain one ionizing radiation curable compound alone, or it may contain two or more ionizing radiation curable compounds.

[0228] When the ionizing ray curable compound is an ultraviolet curable compound, the curable resin composition forming the binder component 46 may also include additives such as photopolymerization initiators and photopolymerization accelerators. Examples of photopolymerization initiators include one or more selected from acetophenone, benzophenone, α-hydroxyalkyl phenyl ketone, mischlerone, benzoin, benzoyl benzoate, benzoylbenzoate, α-acyl oxime ester, α-aminoalkyl phenyl ketone, and thioxanones. Photopolymerization accelerators can reduce polymerization hindrance caused by air during curing and accelerate the curing speed. Examples of photopolymerization accelerators include one or more selected from isoamyl p-dimethylaminobenzoate and ethyl p-dimethylaminobenzoate.

[0229] (Hollow silica particles and other particles)

[0230] Hollow silica particles 47 have an outer shell layer made of silica. Within the hollow silica particles 47, the interior of the particles surrounded by the outer shell layer is void. Air can be contained within these voids. The hollow silica particles 47 have a refractive index lower than that of silica due to the inclusion of internal voids. The refractive index of the hollow silica particles 47 decreases as the volume of the internal voids increases. The hollow silica particles 47 reduce the overall refractive index of the functional layer 40. By using hollow silica particles 47 with a larger particle size that increase the ratio of internal space, the refractive index of the functional layer 40 can be further reduced.

[0231] The average particle size of the hollow silica particles 47 can be 50 nm or more and 100 nm or less, or 50 nm or more and 90 nm or less, or 50 nm or more and 80 nm or less. The average particle size of the hollow silica particles 47 can be 55 nm or more and 100 nm or less, or 55 nm or more and 90 nm or less, or 55 nm or more and 80 nm or less. The average particle size of the hollow silica particles 47 can be 60 nm or more and 100 nm or less, or 60 nm or more and 90 nm or less, or 60 nm or more and 80 nm or less. The average particle size of the hollow silica particles 47 can be 65 nm or more and 100 nm or less, or 65 nm or more and 90 nm or less, or 65 nm or more and 80 nm or less. By adjusting the average particle size of the hollow silica particles 47 in this way, and combining it with the aforementioned feature (A), it is possible to more effectively suppress the hue observed in the optical sheet 10.

[0232] From the viewpoint of uniformly dispersing hollow silica particles 47 within the functional layer 40, the average particle size (nm) of the hollow silica particles 47 can be smaller than the average thickness (nm) of the functional layer 40. An upper limit can be set on the ratio (%) of the average particle size (nm) of the hollow silica particles 47 to the average thickness (nm) of the functional layer 40. By setting an upper limit on the ratio (%) of the average particle size (nm) of the hollow silica particles 47 to the average thickness (nm) of the functional layer 40, the hollow silica particles 47 can be uniformly dispersed within the functional layer 40. The ratio (%) of the average particle size (nm) of the hollow silica particles 47 to the average thickness (nm) of the functional layer 40 can be 80% or less, 75% or less, 70% or less, 60% or less, or 50% or less.

[0233] There is no specific lower limit set for the ratio (%) of the average particle size of the hollow silica particles 47 to the average thickness of the functional layer 40. The ratio (%) of the average particle size of the hollow silica particles 47 to the average thickness of the functional layer 40 can be 10% or more, 20% or more, or 30% or more.

[0234] The ratio (%) of the average particle size of the hollow silica particles 47 to the average thickness of the functional layer 40 can be within the following ranges: This ratio (%) can be 10% or more and 80% or less; 10% or more and 75% or less; 10% or more and 70% or less; 10% or more and 60% or less; 10% or more and 50% or less. This ratio (%) can be 20% or more and 80% or less; 20% or more and 75% or less; 20% or more and 70% or less; 20% or more and 60% or less; 20% or more and 50% or less. This ratio (%) can be 30% or more and 80% or less; 30% or more and 75% or less; 30% or more and 70% or less; 30% or more and 60% or less; 30% or more and 50% or less. By adjusting the ratio of the average particle size of the hollow silica particles 47 to the average thickness of the functional layer 40, the hue observed in the optical sheet 10 can be suppressed more effectively by combining it with the aforementioned feature (A).

[0235] The "average particle size" used for hollow silica particles 47 and other particles is a value determined by the following (1) to (3). Particles may sometimes aggregate, but the average particle size is the average primary particle size.

[0236] (1) Observe the cross section of the optical sheet containing particles using a transmission electron microscope (TEM) and obtain the observation image by taking pictures.

[0237] (2) Extract any 10 particles from the observed image and determine the particle size of each particle. Particle size (nm) is the maximum distance between two parallel straight lines that clamp the particle. That is, particle size is the maximum length of the particle in the observed image. The particle size is determined as the particle size (maximum length) of each particle. That is, the particle size is the primary particle size.

[0238] (3) Perform the above operations (1) and (2) five times on the same optical sheet as the test object, and measure the particle size of a total of 50 particles. Take the average value of the total 50 particle size measurements as the average particle size (nm).

[0239] The “average thickness” of functional layer 40 is a value determined by the following (4) to (6).

[0240] (4) Use a transmission electron microscope (TEM) to photograph the cross section of the optical sheet containing the functional layer.

[0241] (5) Measure the thickness of the functional layer at the center of the optical sheet along the surface of the captured image, and the thickness of the functional layer at a position offset 100 nm from the center along the surface of the optical sheet. The thickness is the length (nm) of the functional layer along a direction orthogonal to the surface of the optical sheet.

[0242] (6) Perform the above operations (4) and (5) five times on the same optical sheet as the measurement object, and measure the thickness of the functional layer at a total of 15 locations. The average value of the total 15 thickness measurements is taken as the average thickness (nm) of the functional layer.

[0243] If the proportion of hollow silica particles 47 increases, the refractive index of the functional layer 40 decreases, and the functional layer 40 can exert excellent reflection suppression function. From the viewpoint of enhancing the reflection suppression function of the functional layer 40, a lower limit can be set for the proportion of hollow silica particles 47. The proportion of hollow silica particles 47 relative to 100 parts by mass of binder component 46 can be 100 parts by mass or more, 150 parts by mass or more, or 175 parts by mass or more.

[0244] By setting an upper limit on the content of hollow silica particles 47, the binder component 46 can stably retain the hollow silica particles 47. From the viewpoint of suppressing the shedding of hollow silica particles 47, an upper limit can be set on the content of hollow silica particles 47. The content of hollow silica particles 47 relative to 100 parts by weight of binder component can be 400 parts by weight or less, 300 parts by weight or less, or 250 parts by weight or less.

[0245] The content of hollow silica particles 47 relative to 100 parts by mass of the binder component can be more than 100 parts by mass and less than 400 parts by mass, more than 150 parts by mass and less than 400 parts by mass, or more than 175 parts by mass and less than 400 parts by mass. The content of hollow silica particles 47 relative to 100 parts by mass of the binder component can be more than 100 parts by mass and less than 300 parts by mass, more than 150 parts by mass and less than 300 parts by mass, or more than 175 parts by mass and less than 300 parts by mass. The content of hollow silica particles 47 relative to 100 parts by mass of the binder component can be more than 100 parts by mass and less than 250 parts by mass, more than 150 parts by mass and less than 250 parts by mass, or more than 175 parts by mass and less than 250 parts by mass. By adjusting the content of the hollow silica particles 47 in this way, in combination with the aforementioned feature (A), the hue observed in the optical sheet 10 can be more effectively suppressed.

[0246] Hollow silica particles 47 can be uniformly dispersed within the functional layer 40. By uniformly dispersing the hollow silica particles 47 within the functional layer 40, appropriate coordination parameters can be reduced. By uniformly dispersing the hollow silica particles 47 within the functional layer 40, protrusion of the hollow silica particles 47 from the first surface 11 is suppressed, and the first surface 11 is smoothed. By uniformly dispersing the hollow silica particles 47 within the functional layer 40, thickness deviations in the functional layer 40 can be suppressed.

[0247] From the viewpoint of uniformly dispersing the hollow silica particles 47 within the functional layer 40, the following adjustments are effective. The particle size deviation of the hollow silica particles 47 can be reduced. The average particle size of the hollow silica particles 47 relative to the average film thickness of the binder component 46 can also be adjusted as described above. The affinity between the hollow silica particles 47 and the binder component 46 can also be adjusted. The content ratio of the hollow silica particles 47 can also be adjusted as described above.

[0248] Functional layer 40 may also contain particles other than hollow silica particles 47. Functional layer 40 may also contain inorganic particles other than hollow silica particles 47. Functional layer 40 may also contain magnesium fluoride particles in addition to hollow silica particles 47. Functional layer 40 may also contain metal oxide particles other than hollow silica particles 47. Functional layer 40 may also contain solid silica particles in addition to hollow silica particles 47. Functional layer 40 may also contain organic particles in addition to hollow silica particles 47.

[0249] Solid silica particles are non-hollow silica particles. Solid silica particles are particles without internal cavities. Solid silica particles can be solid silica particles.

[0250] The average particle size of solid silica particles is typically smaller than that of hollow silica particles 47. Therefore, solid silica particles can be incorporated into the functional layer 40 between adjacent hollow silica particles 47. By including solid silica particles in an appropriate proportion within the functional layer 40, the hollow silica particles 47 can be uniformly dispersed within the functional layer 40.

[0251] There is no particular limitation on the average particle size of solid silica particles. The average particle size of solid silica particles can be between 5 nm and 20 nm, or between 5 nm and 15 nm.

[0252] The content of solid silica particles relative to 100 parts by weight of the binder can be 10 parts by weight or more, 50 parts by weight or more, 70 parts by weight or more, or 100 parts by weight or more. The content of solid silica particles relative to 100 parts by weight of the binder can be less than 200 parts by weight, less than 150 parts by weight, or less than 100 parts by weight.

[0253] The functional layer 40 may contain particles other than silica particles. Examples of particles other than silica particles in the functional layer 40 include elemental forms or mixtures of oxides of any of the following: alumina, titanium, tantalum, zirconium, chromium, niobium, cerium, hafnium, and yttrium. The particles other than silica particles in the functional layer 40 may also be hollow particles with internal spaces. Alternatively, the particles other than silica particles in the functional layer 40 may be solid particles without internal spaces.

[0254] Functional layer 40 may contain alumina particles as particles other than silica particles. Alumina particles have a low refractive index among metal oxides. Alumina is aluminum oxide represented by Al2O3. Al2O3, α-type, γ-type, σ-type, and mixtures thereof are known as alumina. The alumina particles may be surface-modified alumina particles. Examples of modified alumina particles include (meth)acrylate-modified alumina particles and organosilicon-modified alumina particles.

[0255] The average particle size of particles other than silica particles and the average particle size of alumina particles can be 5nm to 20nm, 5nm to 15nm, 10nm to 20nm, or 10nm to 15nm.

[0256] The shape of the hollow silica particles 47, solid silica particles, and alumina dispersed in the functional layer 40 is not particularly limited. The shape of the particles contained in the functional layer 40 can be approximately spherical, rod-shaped, plate-shaped, fibrous, or irregular, such as spherical, ellipsoidal, polyhedral, or similar shapes.

[0257] The surface of the particles contained in the functional layer 40 can be coated with a silane coupling agent. The silane coupling agent may contain (meth)acryloyl or epoxy groups. By subjecting the particles to surface treatment with a silane coupling agent, the affinity between the particles and the binder components is improved, and the particles are less prone to aggregation. By coating the hollow silica particles 47 with a silane coupling agent, the hollow silica particles 47 can be uniformly dispersed within the functional layer 40.

[0258] Examples of silane coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- Triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane, etc. Specifically, it can be one or more selected from 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane and 3-methacryloxypropyltriethoxysilane.

[0259] (Method for creating functional layers)

[0260] The functional layer 40 can be made using a coating liquid for functional layers containing a curable resin composition and hollow silica particles 47. Alternatively, the functional layer 40 can be obtained by curing a coating film made from the coating liquid for functional layers. In this example, the coating liquid for functional layers used to make the functional layer 40 may contain additives such as antistatic agents, antioxidants, surfactants, dispersants, and ultraviolet absorbers.

[0261] The coating liquid for the functional layer may contain a silicone-based leveling agent (silicone compound) as an additive. By including a silicone-based leveling agent in the coating liquid for the functional layer, the protrusion of hollow silica particles 47 from the first surface 11 is suppressed, and the first surface 11 is smoothed. By including a silicone-based leveling agent in the coating liquid for the functional layer, the hollow silica particles 47 can be uniformly dispersed within the functional layer 40. Therefore, thickness deviations in the functional layer 40 can be suppressed, and tinting observed in the optical sheet 10 can be suppressed. The silicone-based leveling agent imparts excellent slip properties and excellent anti-fouling properties (fingerprint wiping resistance, large contact angle with pure water and hexadecane) to the surface of the functional layer 40.

[0262] Anti-glare layer

[0263] The anti-glare layer 30 has an anti-glare function. The anti-glare layer 30 imparts anti-glare properties to the optical element 10. The anti-glare layer 30 includes a first surface 31 and a second surface 32. The first surface 31 faces a first side in the first direction D1. The second surface 32 faces a second side in the first direction D1. The first surface 31 may be a surface with irregularities 31X. The second surface 32 may be a flat surface. The anti-glare layer 30 is located between the functional layer 40 and the substrate 20 in the first direction D1. The anti-glare layer 30 may be connected to the substrate 20 on the second surface 32. The anti-glare layer 30 may be bonded to the substrate 20 on the second surface 32.

[0264] exist Figure 1 In the example shown, the functional layer 40 constitutes the first surface 11 of the optical sheet 10. The functional layer 40 is a very thin layer that extends along the uneven surface 31X. The first surface 11 becomes an uneven surface 11X containing uneven surfaces corresponding to the uneven surfaces 31X. In the first surface 11, which is the uneven surface 11X, ambient light from the environment in which the optical sheet 10 is disposed diffuses and reflects. Due to this diffusion and reflection, the background image of the environment in which the optical sheet 10 is disposed is suppressed from being projected onto the optical sheet 10. Thus, the anti-glare layer 30 and the optical sheet 10 perform an anti-glare function.

[0265] (Method for manufacturing an anti-glare layer)

[0266] The anti-glare layer 30 can be manufactured, for example, by (X) shaping using an embossing roller, (Y) etching, (Z) molding using a mold, or (W) forming a coating film. According to the manufacturing method (Z), a textured surface 31X of the desired shape can be stably manufactured. In the manufacturing method (W), an anti-glare coating liquid for forming the anti-glare layer 30 is used. The anti-glare layer 30 is obtained by drying and curing the coating film of the anti-glare coating liquid. The manufacturing method (W) is excellent in terms of productivity and handling of various product types. As the manufacturing method (W), two methods can be used. In the first method (W1), a coating liquid containing a binder resin and particles is applied, forming textures caused by the presence of particles. In the second method (W2), a coating liquid containing any resin and a resin with poor compatibility is applied, causing the resin phase to separate and forming textures. The first method (W1) allows for easy control of the textured surface 31X.

[0267] The average thickness of the anti-glare layer 30 can be determined by considering factors such as curl suppression, mechanical strength, hardness, and toughness. The average thickness of the anti-glare layer can be greater than 2 μm and less than 10 μm, or greater than 4 μm and less than 8 μm.

[0268] The "average thickness" of the anti-glare layer 30 is a value determined by the following (7) to (9).

[0269] (7) Use a transmission electron microscope (TEM) to photograph the cross section of the optical sheet containing the anti-glare layer.

[0270] (8) Measure the thickness of the anti-glare layer at the center of the optical sheet in the captured image, and the thickness of the target layer at a position offset 50 μm from the center along the optical sheet. The thickness is the length (μm) of the target layer along a direction orthogonal to the optical sheet.

[0271] (9) Perform the above operations (7) and (8) five times on the same optical sheet as the measurement object, and measure the thickness of the anti-glare layer at a total of 15 locations. Take the average value of the total 15 thickness measurements as the average thickness (μm) of the anti-glare layer.

[0272] <ingredients>

[0273] The anti-glare layer mainly consists of resin components, and may also contain additives as needed. Examples of additives include organic and inorganic particles, refractive index modifiers, antistatic agents, antifouling agents, ultraviolet absorbers, light stabilizers, antioxidants, viscosity modifiers, and thermal polymerization initiators.

[0274] like Figure 1 and Figure 5As shown, the anti-glare layer 30 manufactured by the above-described (W) method may comprise resin 36 and particles 37. Particles 37 may be organic particles or inorganic particles. The anti-glare layer 30 may comprise both organic and inorganic particles as particles 37.

[0275] (Organic granules)

[0276] Examples of materials that can be used as organic particles include polymethyl methacrylate, polyacrylic acid-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, organosilicon, fluorinated resins, and polyester resins.

[0277] The average particle size of the organic particles 37 can be greater than 1.0 μm and less than 7.0 μm, greater than 1.5 μm and less than 6.0 μm, or greater than 1.7 μm and less than 5.0 μm.

[0278] The ratio of the average thickness T of the anti-glare layer to the average particle size D of the organic particles, D / T, can be greater than 0.10 and less than 3.5, greater than 0.20 and less than 2.0, greater than 0.30 and less than 1.0, or greater than 0.50 and less than 0.70.

[0279] The proportion of organic particles relative to 100 parts by weight of the binder resin can be between 10 and 200 parts by weight, between 15 and 170 parts by weight, or between 20 and 150 parts by weight. By keeping the proportion of particles below 200 parts by weight, it is possible to suppress the detachment of organic particles from the anti-glare layer 30.

[0280] (Inorganic particles)

[0281] Examples of inorganic particulate materials include silicon dioxide, alumina, zirconium oxide, and titanium dioxide. Inorganic particles can be amorphous inorganic particles. Amorphous silicon dioxide is an example of an amorphous inorganic particle.

[0282] The average particle size of inorganic particles can be greater than 1 nm and less than 200 nm, greater than 2 nm and less than 100 nm, or greater than 5 nm and less than 50 nm.

[0283] The proportion of inorganic particles relative to 100 parts by weight of the binder resin can be more than 5 parts by weight and less than 100 parts by weight, more than 15 parts by weight and less than 150 parts by weight, or more than 20 parts by weight and less than 80 parts by weight.

[0284] (resin)

[0285] The resin component contained in the anti-glare layer 30 may include 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. Resin 36 may contain both cured products of the curable resin composition and cured products of the ionizing radiation-curable resin composition.

[0286] The resin curing agent contained in the anti-glare layer 30 may be the same as the resin curing agent contained in the functional layer 40.

[0287] When resin 36 comprises a cured product of an ionizing radiation-curable resin composition, resin 36 may have the following (C1) or (C2) composition.

[0288] (C1) Resin 36 comprises a cured product of an ionizing radiation curable resin composition and a thermoplastic resin.

[0289] (C2) Resin 36 substantially contains only the cured product of the ionizing radiation curable resin composition, and contains more than 70% by mass of monomer components as ionizing radiation curable compounds contained in the ionizing radiation curable resin composition.

[0290] When the above configuration (C1) is adopted, the viscosity of the anti-glare coating liquid used to form the anti-glare layer 30 becomes higher due to the thermoplastic resin. Within the anti-glare coating liquid, the particles 37 do not easily settle.

[0291] Examples of thermoplastic resins include polystyrene resins, polyolefin resins, ABS resins (including heat-resistant ABS resins), AS resins, AN resins, polyphenylene ether resins, polycarbonate resins, polyacetal resins, acrylic resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polysulfone resins, and polyphenylene sulfide resins.

[0292] The weight-average molecular weight of thermoplastic resins can be above 20,000 and below 200,000, above 30,000 and below 150,000, or above 50,000 and below 100,000. The weight-average molecular weight is determined by GPC analysis and is the average molecular weight converted from standard polystyrene.

[0293] In the above configuration (C1), the mass ratio of the cured product of the ionizing radiation-curable resin composition to the thermoplastic resin can be 60:40 to 90:10, or 70:30 to 80:20. By making the thermoplastic resin at 10 parts by mass or more relative to 90 parts by mass of the cured product of the ionizing radiation-curable resin composition, the effect of increased viscosity of the coating liquid for the anti-glare layer can be effectively obtained. By making the thermoplastic resin at 40 parts by mass or less relative to 60 parts by mass of the cured product of the ionizing radiation-curable resin composition, the mechanical strength of the anti-glare layer can be improved.

[0294] With the above-described configuration (C2), the bottom of the anti-glare layer 30 is covered with particles 37, and the particles 37 are easily stacked in certain areas. Furthermore, a very thin layer of resin 36 covers the particles 37.

[0295] In the above configuration (C2), the cured product of the ionizing radiation-curable resin composition, relative to the total amount of resin 36, can be 90% by mass or more, 95% by mass or more, or 100% by mass. In the above configuration (C2), the monomer component, relative to the total amount of the ionizing radiation-curable compound, can be 70% by mass or more, or 75% by mass or more. When using the above configuration (C2), the monomer component can be a multifunctional (meth)acrylate compound.

[0296] (Coating liquid for anti-glare layer)

[0297] In the manufacturing method described above (W), the anti-glare layer 30 can be manufactured by drying and curing a coating film of an anti-glare coating liquid. The anti-glare coating liquid used to manufacture the anti-glare layer 30 may contain a curable resin composition and particles. The anti-glare coating liquid may contain additives such as antistatic agents, antioxidants, surfactants, dispersants, and ultraviolet absorbers.

[0298] The coating liquid for the anti-glare layer may contain a silicone-based leveling agent (silicone compound) as an additive. By including a silicone-based leveling agent in the coating liquid for the anti-glare layer, it is possible to suppress the protrusion of particles 37 from the first surface 11.

[0299] <Functional Layer 2>

[0300] Figure 5 The optical sheet 10 shown includes a functional layer 40 and a second functional layer 50. Figure 5 In the example shown, functional layer 40 can be connected with... Figure 1 The optical sheet 10 shown also includes the aforementioned functional layer 40. That is, the functional layer 40 constitutes the first surface 11. For example... Figure 2A and Figure 2BAs shown, functional layer 40 may include binder component 46 and hollow silica particles 47. Functional layer 40 is a low refractive index layer. The low refractive index layer has a lower refractive index than the adjacent second functional layer 50.

[0301] The second functional layer 50 is located between the functional layer 40 and the anti-glare layer 30 in the first direction D1. The second functional layer 50 has a refractive index higher than that of the anti-glare layer 30 and the functional layer 40. The functional layer 40, as a low refractive index layer, and the second functional layer 50, as a high refractive index layer, function as low-reflection layers or reflection suppression layers, and suppress reflection from the first surface 11.

[0302] As a specific component, the second functional layer 50 may include an adhesive component and particles. The particles may be high-refractive-index particles. The refractive index of the particles may be higher than that of the adhesive component. The second functional layer 50 increases its refractive index by including high-refractive-index particles. The refractive index of the second functional layer 50 is higher than that of the anti-glare layer 30.

[0303] From the perspective of reflection suppression, the refractive index and average thickness of the second functional layer 50 can be set as follows: The refractive index of the second functional layer can be 1.55 or higher and 1.85 or lower, 1.56 or higher and 1.85 or lower, 1.55 or higher and 1.75 or lower, or 1.56 or higher and 1.75 or lower. The thickness of the second functional layer 50 can be 50 nm or higher and 200 nm or lower, or 50 nm or higher and 180 nm or lower.

[0304] The adhesive component contained in the second functional layer 50 may be the same as that contained in the functional layer 40. The adhesive component contained in the second functional layer 50 may include a cured product of a curable resin composition. The curable resin composition may include one or more of a thermosetting resin composition and an ionizing radiation-curable resin composition.

[0305] The second functional layer 50 may contain one or more of organic and inorganic particles. Examples of particles contained in the second functional layer 50 include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

[0306] The second functional layer 50 can be manufactured using a wet process, similar to functional layer 40. The second functional layer 50 can be manufactured using a second functional layer coating liquid for forming the second functional layer 50. The second functional layer 50 can be manufactured by drying and curing a coating film of the second functional layer coating liquid. The second functional layer coating liquid used to manufacture the second functional layer 50 may contain additives suitable for use with functional layer coating liquids.

[0307] <<Methods for Manufacturing Optical Sheets>>

[0308] The anti-glare layer 30, functional layer 40, and second functional layer 50 included in the optical sheet 10 can be manufactured using a wet process. In the wet process, a coating liquid containing the components constituting each layer 30, 40, and 50 is prepared. First, the coating liquid is applied to the surface on which each layer 30, 40, and 50 is to be formed. Then, the coating film of the coating liquid is dried and cured to obtain each layer 30, 40, and 50. In addition to the resin composition and particles used to form each layer, the coating liquid may also contain a solvent. The resin composition may contain solid components constituting each layer and additives such as polymerization initiators.

[0309] The optical sheet 10, comprising a substrate 20, an anti-glare layer 30, and a functional layer 40, can be manufactured as follows.

[0310] First, prepare an anti-glare coating liquid for forming the anti-glare layer 30. Next, apply the anti-glare coating liquid onto the substrate 20 to form a coating film. Then, dry the coating film. Next, allow the coating film to cure. Thus, an anti-glare layer 30 is formed on the substrate 20.

[0311] Next, a coating liquid for forming the functional layer 40 is prepared. Then, the coating liquid is applied onto the anti-glare layer 30 to form a coating film. Next, the coating film is dried. Next, the coating film is cured. Thus, the functional layer 40 is formed on the anti-glare layer 30, resulting in the optical film 10.

[0312] It should be noted that when the anti-glare layer 30 is made on the substrate 20 in an uncured or semi-cured state and the functional layer 40 is cured, the anti-glare layer 30 and the functional layer 40 can be completely cured together.

[0313] In manufacturing Figure 5 In the case of the optical sheet 10 shown, a second functional layer 50 is formed on the anti-glare layer 30 after the anti-glare layer 30 is formed and before the functional layer 40 is formed. The second functional layer 50 is coated onto the anti-glare layer 30 with a coating liquid, and the coating is dried and cured to obtain the second functional layer 50. Next, by forming the functional layer 40 on the second functional layer 50, a second functional layer 40 is obtained. Figure 5 The optical sheet 10 is shown. It should be noted that when one or more of the anti-glare layer 30 and the second functional layer 50 are made in an uncured or semi-cured state and the functional layer 40 is cured, one or more of the anti-glare layer 30 and the second functional layer 50 can be completely cured together with the functional layer 40.

[0314] The coating solution may contain a solvent. The solvent can adjust the viscosity of the coating solution. The solvent can also dissolve or disperse the various components within the coating solution. Examples of solvents include one or more of the following: ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), carbon halides (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (butanol, cyclohexanol, etc.), cellosolvers (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), glycol ethers (1-methoxy-2-propyl acetate, etc.), and amides (dimethylformamide, dimethylacetamide, etc.).

[0315] When the solvent evaporates too quickly, vigorous convection occurs during the drying of the coating solution. The hollow silica particles 47 contained in the coating solution move towards the coating surface due to convection caused by solvent evaporation during drying. These particles moving towards the coating surface can protrude from the first surface or form protrusions on the first surface 11 in the fabricated optical sheet. A large number of hollow silica particles 47 are observed on the first surface 11 in the optical sheet. The appropriate coordination parameter is greater than the range specified in feature (A). From the viewpoint of reducing the appropriate coordination parameter, the coating solution can contain a solvent with a slow evaporation rate.

[0316] As a solvent with a relatively slow evaporation rate, a high-boiling-point solvent can be used. Examples of high-boiling-point solvents include PMA: propylene glycol monomethyl ether acetate. Examples of solvents with a boiling point higher than PMA include diacetone alcohol. Examples of solvents with a boiling point higher than diacetone alcohol include benzyl acetate.

[0317] The drying temperature during the drying of the coating solution can be adjusted. The airflow and velocity of the drying air during the drying process can also be adjusted. For example, by weakening the drying conditions, rapid evaporation of the solvent can be suppressed. That is, by adjusting the drying conditions, the movement of hollow silica particles 47 towards the coating surface during the drying of the coating solution can also be suppressed. Appropriate coordination parameters can also be adjusted by regulating the drying conditions.

[0318] Drying conditions can be appropriately selected based on the characteristics of the materials used. When using a coating solution that easily penetrates the substrate, the drying time can be shortened. By reducing the amount of penetration into the substrate, the concentration of hollow silica particles 47 on the coating surface can be suppressed. When using hollow silica particles 47 that easily aggregate, shortening the drying time can suppress the aggregation of hollow silica particles 47 on the coating surface. Therefore, the hollow silica particles 47 can be uniformly dispersed within the functional layer 40.

[0319] Heating the substrate 20 during the drying of the coating liquid can promote its penetration into the substrate 20. Therefore, by gradually increasing the drying temperature, the coating liquid can be dried while simultaneously inhibiting its penetration into the substrate 20. The drying conditions can be changed in the first and second halves of the coating drying process.

[0320] The proportion of solid components in the coating liquid for forming the functional layer can also be adjusted. If the proportion of solid components increases, the viscosity of the coating liquid for forming the functional layer increases. According to this example, it is easy to maintain the uniform dispersion of hollow silica particles 47 within the coating film. Therefore, appropriate coordination parameters can also be adjusted according to the proportion of solid components in the coating liquid for forming the functional layer.

[0321] Examples of methods for curing coatings that form various layers include irradiation with ionizing rays such as ultraviolet light and electron beams, and heating. Curing processes using ionizing rays are highly productive in terms of achieving curing in a short time.

[0322] As described above, optical sheet 10 can be manufactured.

[0323] As explained above, by adjusting the formulation of the coating liquid, the type of solvent, and the drying conditions of the coating film, appropriate coordination parameters based on the hollow silica particles 47 observed on page 11 can be adjusted. Alternatively, or based on these methods, other methods can be used to adjust the appropriate coordination parameters. For example, the appropriate coordination parameters can also be adjusted by the affinity between the hollow silica particles 47 and the binder component 46. By using the binder component 46, which has a high affinity for the hollow silica particles 47, the binder component 46 easily surrounds the hollow silica particles 47. Thus, the hollow silica particles 47 are uniformly dispersed within the functional layer 40, and the appropriate coordination parameters can be easily adjusted to the range specified in feature (A).

[0324] In addition to the steps described above for manufacturing an optical sheet, the method for manufacturing an optical sheet may also include a step of selecting the optical sheet 10 to be manufactured. The step of selecting the optical sheet 10 may include: determining an appropriate coordination parameter based on the hollow silica particles 47 observed on the first surface 11; and selecting an optical sheet with an appropriate coordination parameter of 1.0 or higher and 2.0 or lower. Optical sheets with an appropriate coordination parameter of 1.0 or higher and 2.0 or lower have difficulty observing hues. According to the selection method, optical sheets with difficult-to-observe hues can be selected with high precision without requiring sensory testing by multiple test subjects.

[0325] <<<Items>>>

[0326] According to the above-described wet-process-based manufacturing method of the optical sheet 10, such as Figure 6As shown, a strip of sheet 5 containing multiple optical elements 10 can be manufactured. Optical elements 10 are obtained by cutting the strip of sheet 5 to a predetermined size. According to this example, optical elements 10 of various sizes can be obtained from the strip of sheet 5 as needed. Therefore, optical elements 10 of various sizes can be provided as needed. Figure 6 As shown, by processing the sheet article 5 as a roll 7 wound around the winding core with the winding axis RA as the center, the processability of the sheet article 5 can be improved.

[0327] <<<Polarizing Plate>>>

[0328] The optical element 10 in this embodiment can be applied to the polarizer 60. Figure 7 In the example shown, polarizer 60 includes a first protective sheet 61, a polarizing element 62, and a second protective sheet 63. The first protective sheet 61 and the second protective sheet 63 sandwich the polarizing element 62 in the middle, covering it from both sides. At least one of the first protective sheet 61 and the second protective sheet 63 may include an optical sheet 10. The first protective sheet 61, located on the first side (observer side) in the first direction D1, may include the optical sheet 10. When only one of the first protective sheet 61 and the second protective sheet 63 includes the optical sheet 10, the other protective sheet may be a resin film.

[0329] According to the optical plate 10, the background image reflected into the optical plate 10 can be effectively suppressed. Therefore, the image located behind the polarizer 60 can be clearly observed. Furthermore, as described above, the hue observed in the optical plate 10 is suppressed. Therefore, the hue of the image observed behind the polarizer 60 due to the hue of the optical plate 10 can be effectively suppressed.

[0330] Polarizing element 62 allows one linearly polarized light component to pass through while blocking another linearly polarized light component. Polarizing element 62 can also be an absorptive polarizing element that absorbs the other linearly polarized light component. Polarizing element 62 can also be a reflective polarizing element that reflects the other linearly polarized light component. Polarizing element 62 can also be a sheet-type polarizing element, such as a polyvinyl alcohol film, polyvinyl formal film, polyvinyl acetal film, or ethylene-vinyl acetate copolymer saponified film, which has been dyed and stretched using iodine or the like. Polarizing element 62 can also be a wire grid type polarizing element composed of multiple parallel metal wires. Polarizing element 62 can be a coated polarizing element coated with lyotropic liquid crystal or dichroic guest-host material, or a multilayer thin film type polarizing element.

[0331] <<<Display Devices>>>

[0332] The optical sheet 10 of this embodiment can be applied to a display device 65. Figure 8In the example shown, the display device 65 includes a display element 66 and an optical sheet 10. The display element 66 includes an image forming surface 66a for displaying images. The optical sheet 10 overlaps the display element 66 with its second surface 12 facing the image forming surface 66a. The optical sheet 10 can be bonded to the display element 66 via a bonding layer comprising an adhesive, bonding agent, etc. The display element 66 is not particularly limited. Examples of display elements 66 include liquid crystal display elements, EL display elements, plasma display elements, electronic paper elements, etc.

[0333] By utilizing the reflection suppression and anti-glare functions of the optical sheet 10, the reflection of the background of the environment where the display device 65 is located can be suppressed from entering the optical sheet 10. Therefore, an observer can clearly observe the image displayed by the display element 66 through the optical sheet 10. As described above, hue observation in the optical sheet 10 is suppressed. Therefore, the hue of the image displayed by the display element 66 can be effectively suppressed from changing due to the hue of the optical sheet 10. As described above, according to the display device 65 including the optical sheet 10, image degradation displayed by the display device 65 can be effectively suppressed. The observer can observe a high-quality image.

[0334] <<<Panel>>>

[0335] The optical sheet 10 of this embodiment can be applied to various purposes. Figure 9 A panel 70 with an optical sheet 10 is shown. The panel 70 includes the optical sheet 10 and a bonded article 71 to which the optical sheet 10 is bonded. The panel 70 constitutes a reflection-suppressing article with the function of suppressing reflection through the optical sheet 10. The optical sheet 10 overlaps with the bonded article 71 face-to-face with its second surface 12. The optical sheet 10 may also be bonded to the bonded article 71 by a bonding layer including adhesive material, bonding agent, etc. Examples of the bonded article 71 include dashboards, clocks, display cases, shop windows, and windows. The bonded article 71 may also be a transparent substrate such as glass or resin film.

[0336] According to the optical sheet 10, the reflection of background images into the optical sheet 10 can be effectively suppressed. Therefore, the image located behind the panel 70 can be clearly observed. Furthermore, as described above, the hue observed in the optical sheet 10 is suppressed. Therefore, the hue of the image observed behind the panel 70 due to the hue of the optical sheet 10 can be effectively suppressed.

[0337] Example

[0338] This disclosure is illustrated in more detail by way of examples. This disclosure is not limited to the following examples.

[0339] <<<1. Fabrication of Optical Sheets>>>

[0340] Optical sheets of Examples 1-4 and Comparative Examples 1-3 were prepared.

[0341] <<Example 1>>

[0342] As the substrate, a triacetyl cellulose membrane (TAC membrane) with a thickness of 80 μm was used. The substrate was TD80UL manufactured by Fujifilm.

[0343] The anti-glare coating liquid 1 of the following formulation is applied to a substrate to form a coating film of the anti-glare coating liquid 1. The solid content of the anti-glare coating liquid 1 is 38%. Next, the coating film of the anti-glare coating liquid 1 is dried at 70°C for 30 seconds (drying wind speed 5 m / s) to allow the solvent to evaporate. Then, the coating film is irradiated with a cumulative light intensity of 100 mJ / cm² under a nitrogen atmosphere with an oxygen concentration of 200 ppm or less. 2 Ultraviolet light is emitted. An anti-glare layer consisting of a cured coating is formed on the substrate. The thickness of the anti-glare layer is 5 μm.

[0344] Next, a coating liquid 1 for the functional layer (coating liquid 1 for the low refractive index layer) with the following formulation is applied to the anti-glare layer, forming a coating film of the functional layer coating liquid 1 on the substrate. The solid content of the functional layer coating liquid 1 is 5.0%. Then, the coating film of the functional layer coating liquid 1 is dried at 50°C for 30 seconds (drying air velocity 0.5 m / s), and further dried at 50°C for 30 seconds (drying air velocity 5 m / s) to evaporate the solvent. Next, the coating film is irradiated with a cumulative light intensity of 200 mJ / cm under a nitrogen atmosphere with an oxygen concentration of less than 200 ppm. 2 Ultraviolet light. A functional layer consisting of a cured coating is formed on the anti-glare layer. The thickness of the functional layer is 100 nm. Thus, the optical sheet of Example 1 is obtained.

[0345] <Anti-glare coating liquid 1>

[0346] 30 parts by weight of pentaerythritol triacrylate

[0347] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0348] 70 parts by weight of urethane acrylate oligomer

[0349] (DIC Corporation, product name "LUXYDIR V-4501")

[0350] · 2 parts by weight of organic granules

[0351] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0352] · 4 parts by weight of silica particles

[0353] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0354] · 10 parts by weight of silica particles

[0355] (Average particle size 6.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0356] · 1.5 parts by weight of photopolymerization initiator

[0357] (IGM Resins BV, product name "Omnirad184")

[0358] • 0.3 parts by weight of photopolymerization initiator

[0359] (IGM Resins BV, product name "Omnirad 907")

[0360] · 1.3 parts by weight of photopolymerization initiator

[0361] (Lamberti, product name "ESACUREONE")

[0362] • 0.1 parts by weight of silicone-based leveling agent

[0363] (Momentive Performance Materials, trade name "TSF4460")

[0364] Solvent (toluene) 130.5 parts by weight

[0365] • Solvent (MIBK: methyl isobutyl ketone) 32.6 parts by weight

[0366] <Coating solution 1 for functional layer (Coating solution 1 for low refractive index layer)>

[0367] 100 parts by weight of pentaerythritol triacrylate

[0368] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0369] 175 parts by weight of hollow silica particles

[0370] (Particles with an average particle size of 75 nm, surface-treated with a silane coupling agent containing methacrylyl groups)

[0371] · 7.0 parts by weight of photopolymerization initiator

[0372] (IGM Resins BV, product name "Omnirad127")

[0373] · 40.0 parts by weight of silicone-based leveling agent

[0374] (Momentive Performance Materials, trade name "TSF4460")

[0375] • Solvent (MIBK: Methyl Isobutyl Ketone) 5563.2 parts by weight

[0376] • Solvent (PMA: Propylene glycol monomethyl ether acetate) 744.8 parts by weight

[0377] <<Example 2>>

[0378] Example 2 differs from Example 1 in that it uses anti-glare coating liquid 1 instead of the aforementioned anti-glare coating liquid 2, and also uses functional layer coating liquid 1 instead of the aforementioned functional layer coating liquid 2. Otherwise, using the same materials and methods as Example 1, an optical sheet of Example 2 with the same thickness as Example 1 is obtained. The solid content of anti-glare coating liquid 2 is 35%. The solid content of functional layer coating liquid 2 is 5%.

[0379] <Anti-glare coating liquid 2>

[0380] 30 parts by weight of pentaerythritol triacrylate

[0381] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0382] 70 parts by weight of urethane acrylate oligomer

[0383] (DIC Corporation, product name "LUXYDIR V-4501")

[0384] · 2 parts by weight of organic granules

[0385] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0386] · 11 parts by weight of silica particles

[0387] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0388] · 3 parts by weight of silica particles

[0389] (Average particle size 6.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0390] · 3.0 parts by weight of photopolymerization initiator

[0391] (IGM Resins BV, product name "Omnirad184")

[0392] • 0.5 parts by weight of photopolymerization initiator

[0393] (IGM Resins BV, product name "Omnirad 907")

[0394] • 0.7 parts by weight of photopolymerization initiator

[0395] (Lamberti, product name "ESACUREONE")

[0396] • 0.1 parts by weight of silicone-based leveling agent

[0397] (Momentive Performance Materials, trade name "TSF4460")

[0398] Solvent (toluene) 130.5 parts by weight

[0399] • Solvent (MIBK: methyl isobutyl ketone) 32.6 parts by weight

[0400] <Coating solution 2 for functional layer (Coating solution 2 for low refractive index layer)>

[0401] 100 parts by weight of pentaerythritol triacrylate

[0402] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0403] · 210 parts by weight of hollow silica particles

[0404] (Particles with an average particle size of 75 nm, surface-treated with a silane coupling agent containing methacrylyl groups)

[0405] · 7.0 parts by weight of photopolymerization initiator

[0406] (IGM Resins BV, product name "Omnirad127")

[0407] · 40.0 parts by weight of silicone-based leveling agent

[0408] (Momentive Performance Materials, trade name "TSF4460")

[0409] • Solvent (MIBK: Methyl Isobutyl Ketone) 5367.2 parts by weight

[0410] • Solvent (PMA: Propylene glycol monomethyl ether acetate) 1675.8 parts by weight

[0411] <<Example 3>>

[0412] Example 3 differs from Example 1 in that the anti-glare coating liquid 1 is replaced with the anti-glare coating liquid 3 described below, and the functional layer coating liquid 1 is replaced with the functional layer coating liquid 3 described below. Otherwise, using the same materials and methods as Example 1, an optical sheet of Example 3 with the same thickness as Example 1 is obtained. The solid content of the anti-glare coating liquid 3 is 38%. The solid content of the functional layer coating liquid 3 is 5%.

[0413] <Anti-glare coating liquid 3>

[0414] 30 parts by weight of pentaerythritol triacrylate

[0415] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0416] 70 parts by weight of urethane acrylate oligomer

[0417] (DIC Corporation, product name "LUXYDIR V-4501")

[0418] · 2 parts by weight of organic granules

[0419] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0420] · 11 parts by weight of silica particles

[0421] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0422] · 3.0 parts by weight of photopolymerization initiator

[0423] (IGM Resins BV, product name "Omnirad184")

[0424] • 0.5 parts by weight of photopolymerization initiator

[0425] (IGM Resins BV, product name "Omnirad 907")

[0426] • 0.7 parts by weight of photopolymerization initiator

[0427] (Lamberti, product name "ESACUREONE")

[0428] • 0.1 parts by weight of silicone-based leveling agent

[0429] (Momentive Performance Materials, trade name "TSF4460")

[0430] Solvent (toluene) 146.8 parts by weight

[0431] • Solvent (MIBK: methyl isobutyl ketone) 16.3 parts by weight

[0432] <Coating solution 3 for functional layers (Coating solution 3 for low refractive index layers)>

[0433] 100 parts by weight of pentaerythritol triacrylate

[0434] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0435] · 210 parts by weight of hollow silica particles

[0436] (Particles with an average particle size of 75 nm, surface-treated with a silane coupling agent containing methacrylyl groups)

[0437] · 7.0 parts by weight of photopolymerization initiator

[0438] (IGM Resins BV, product name "Omnirad127")

[0439] · 40.0 parts by weight of silicone-based leveling agent

[0440] (Momentive Performance Materials, trade name "TSF4460")

[0441] • Solvent (MIBK: Methyl Isobutyl Ketone) 6205.1 parts by weight

[0442] • Solvent (PMA: Propylene glycol monomethyl ether acetate) 837.9 parts by weight

[0443] <<Example 4>>

[0444] Example 4 differs from Example 1 in that the anti-glare coating liquid 1 is replaced with the anti-glare coating liquid 4 described below, and the functional layer coating liquid 1 is replaced with the functional layer coating liquid 2 described above. Otherwise, using the same materials and methods as Example 1, an optical sheet of Example 4 with the same thickness as Example 1 is obtained. The solid content of the anti-glare coating liquid 4 is 38%. The solid content of the functional layer coating liquid 2 is 5%.

[0445] <Anti-glare coating liquid 4>

[0446] 30 parts by weight of pentaerythritol triacrylate

[0447] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0448] 70 parts by weight of urethane acrylate oligomer

[0449] (DIC Corporation, product name "LUXYDIR V-4501")

[0450] · 2 parts by weight of organic granules

[0451] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0452] · 4 parts by weight of silica particles

[0453] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0454] · 3.0 parts by weight of photopolymerization initiator

[0455] (IGM Resins BV, product name "Omnirad184")

[0456] • 0.5 parts by weight of photopolymerization initiator

[0457] (IGM Resins BV, product name "Omnirad 907")

[0458] • 0.7 parts by weight of photopolymerization initiator

[0459] (Lamberti, product name "ESACUREONE")

[0460] • 0.1 parts by weight of silicone-based leveling agent

[0461] (Momentive Performance Materials, trade name "TSF4460")

[0462] Solvent (toluene) 130.5 parts by weight

[0463] • Solvent (MIBK: methyl isobutyl ketone) 32.6 parts by weight

[0464] <<Comparative Example 1>>

[0465] Comparative Example 1 differs from Example 1 in that it uses anti-glare coating liquid 1 instead of the anti-glare coating liquid 5 described below. Otherwise, using the same materials and methods as Example 1, an optical film of Comparative Example 1 with the same thickness as Example 1 was obtained. The solid content of the anti-glare coating liquid 5 is 35%. The solid content of the functional layer coating liquid 1 is 5%.

[0466] <Anti-glare coating liquid 5>

[0467] 30 parts by weight of pentaerythritol triacrylate

[0468] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0469] 70 parts by weight of urethane acrylate oligomer

[0470] (DIC Corporation, product name "LUXYDIR V-4501")

[0471] · 2 parts by weight of organic granules

[0472] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0473] · 6 parts by weight of silica particles

[0474] (Average particle size 6.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0475] · 1.5 parts by weight of photopolymerization initiator

[0476] (IGM Resins BV, product name "Omnirad184")

[0477] • 0.3 parts by weight of photopolymerization initiator

[0478] (IGM Resins BV, product name "Omnirad 907")

[0479] · 1.3 parts by weight of photopolymerization initiator

[0480] (Lamberti, product name "ESACUREONE")

[0481] • 0.1 parts by weight of silicone-based leveling agent

[0482] (Momentive Performance Materials, trade name "TSF4460")

[0483] Solvent (toluene) 130.5 parts by weight

[0484] • Solvent (MIBK: methyl isobutyl ketone) 32.6 parts by weight

[0485] <<Comparative Example 2>>

[0486] Comparative Example 1 differs from Example 1 in that it replaces the anti-glare coating liquid 1 with the anti-glare coating liquid 6 described below, and in that it replaces the functional layer coating liquid 1 with the functional layer coating liquid 2 described above. Otherwise, using the same materials and methods as Example 1, an optical sheet of Comparative Example 2 with the same thickness as Example 1 was obtained. The solid content of the anti-glare coating liquid 6 is 38%. The solid content of the functional layer coating liquid 2 is 5%.

[0487] <Anti-glare coating liquid 6>

[0488] 30 parts by weight of pentaerythritol triacrylate

[0489] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0490] 70 parts by weight of urethane acrylate oligomer

[0491] (DIC Corporation, product name "LUXYDIR V-4501")

[0492] · 2 parts by weight of organic granules

[0493] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0494] · 15 parts by weight of silica particles

[0495] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0496] · 3.0 parts by weight of photopolymerization initiator

[0497] (IGM Resins BV, product name "Omnirad184")

[0498] • 0.5 parts by weight of photopolymerization initiator

[0499] (IGM Resins BV, product name "Omnirad 907")

[0500] • 0.7 parts by weight of photopolymerization initiator

[0501] (Lamberti, product name "ESACUREONE")

[0502] • 0.1 parts by weight of silicone-based leveling agent

[0503] (Momentive Performance Materials, trade name "TSF4460")

[0504] Solvent (toluene) 146.8 parts by weight

[0505] • Solvent (MIBK: methyl isobutyl ketone) 16.3 parts by weight

[0506] <<Comparative Example 3>>

[0507] Comparative Example 3 differs from Example 1 in that the anti-glare coating liquid 1 is replaced with the anti-glare coating liquid 7 described below. Otherwise, using the same materials and methods as Example 1, an optical sheet of Comparative Example 2 with the same thickness as Example 1 was obtained. The solid content of the anti-glare coating liquid 6 is 38%. The solid content of the functional layer coating liquid 1 is 5%.

[0508] <Anti-glare coating liquid 7>

[0509] 30 parts by weight of pentaerythritol triacrylate

[0510] (Nippon Kayaku Co., Ltd., product name "KAYARAD-PET-30")

[0511] 70 parts by weight of urethane acrylate oligomer

[0512] (DIC Corporation, product name "LUXYDIR V-4501")

[0513] · 2 parts by weight of organic granules

[0514] (Average particle size 2.0μm, with over 90% of particles having a diameter of 1.8–2.2μm, refractive index 1.515, spherical polyacrylic acid-styrene copolymer, Sekisui Chemicals Co., Ltd.)

[0515] · 3 parts by weight of silica particles

[0516] (Average particle size 4.0 μm, gel-processed amorphous silica, manufactured by Fuji Silysia Chemical Co., Ltd.)

[0517] · 3.0 parts by weight of photopolymerization initiator

[0518] (IGM Resins BV, product name "Omnirad184")

[0519] • 0.5 parts by weight of photopolymerization initiator

[0520] (IGM Resins BV, product name "Omnirad 907")

[0521] • 0.7 parts by weight of photopolymerization initiator

[0522] (Lamberti, product name "ESACUREONE")

[0523] • 0.1 parts by weight of silicone-based leveling agent

[0524] (Momentive Performance Materials, trade name "TSF4460")

[0525] Solvent (toluene) 130.5 parts by weight

[0526] • Solvent (MIBK: methyl isobutyl ketone) 32.6 parts by weight

[0527] <<<2. Measurement and Evaluation>>>

[0528] As described below, the optical sheets of the Examples and Comparative Examples were measured and evaluated. The measurement environment for each measurement and evaluation was set to a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. Before each measurement and evaluation, the sample to be tested was placed in the above-described measurement environment for 16 hours.

[0529] <<2-1. Transmitted Haze>>

[0530] Samples measuring 10cm × 10cm were cut from the optical films of the examples and comparative examples. The samples were visually confirmed to be free of dust, scratches, or other abnormalities. The transmittance haze (%) of each sample was measured using the method described above. The transmittance haze was measured using a haze meter "HM-150" manufactured by Murakami Color Technology Research Institute. The results of the transmittance haze measurement are shown in the "Transmittance Haze" column of Table 1.

[0531] <<2-2. Visual Reflectivity>>

[0532] Samples measuring 5cm × 10cm were cut from the optical sheets of the examples and comparative examples. The samples were visually inspected to ensure they were free of dust, scratches, or other abnormalities. As described above, a black plate was adhered to the surface of the sample, which was formed by the second side of the optical sheet, using an optically transparent adhesive. The black plate was a Kuraray "COMOGLASS K, Color Code: 502K (thickness 2mm)". The visual reflectance (%) of each sample was measured using the method described above. Visual reflectance is the SCI Y value. The visual reflectance was measured using a Konica Minolta spectrophotometer "CM-600d". The light source was a D65 light source. The results of the visual reflectance measurements are shown in the "Visual Reflectance" column of Table 1.

[0533] <<2-3. Value and Value >>

[0534] Samples measuring 5cm × 10cm were cut from the optical sheets of the examples and comparative examples. The samples were visually inspected to ensure they were free of dust, scratches, or other abnormalities. As described above, a black plate was adhered to the surface of the sample, which is formed by the second side of the optical sheet, using an optically transparent adhesive. The black plate was a Kuraray "COMOGLASS K, Color Code: 502K (Thickness 2mm)". The optical sheets of each example were measured using the method described above. Color system Value and value. Value and The values ​​were determined using a Konica Minolta spectrophotometer "CM-600d". The results of the value determination are shown in Table 1. The "Value" column. The results of the value determination are shown in Table 1. The "Value" column.

[0535] <<2-4. Visual reflectance and The product of values, visual reflectance and Product of values ​​>>

[0536] The visual reflectance measured for each case was calculated and The absolute value of the product of values. (This refers to the relationship between visual reflectance and...) The absolute value of the product of values ​​is shown in Table 2 under "|Y·". The column “|” calculates the visual reflectance and the results for each measurement. The absolute value of the product of values. (This refers to the relationship between visual reflectance and...) The absolute value of the product of values ​​is shown in Table 2 under "|Y·". |” column.

[0537] <<2-4. Appropriate Coordination Parameters>>

[0538] Samples measuring 5mm × 5mm were cut from the optical sheets of the examples and comparative examples. The samples were visually confirmed to be free of dust, scratches, or other abnormalities. Using the method described above, appropriate coordination parameters of the hollow silica particles observed on the first surface were determined for each example's optical sheet.

[0539] First, using a scanning electron microscope (SEM), observation images were acquired of 16 subdivided regions arranged in a 4x4 grid within the measurement area on the first plane. A Hitachi High-Tech SU-9000 ultra-high resolution field emission scanning electron microscope was used as the scanning electron microscope. As an example, the observation images acquired using the scanning electron microscope are shown below. Figure 4A .

[0540] Next, the 16 images obtained from the scanning electron microscope were binarized using the image processing software "ImageJ 1.52e" and "Fiji". As an example, the binarized image of the first surface is shown below. Figure 4B . Figure 4B The binary image shown is obtained by analyzing... Figure 4A The image of the first side shown is obtained by binarizing it.

[0541] Then, using ImageJ 1.52e and Fiji, the centroid positions of the hollow silica particles observed on surface 11 were determined based on the binarized binary image. As an example, the distribution of the determined centroids of the hollow silica particles is shown below. Figure 4C . Figure 4C The distribution of the center of gravity shown is based on Figure 4A and Figure 4B It was generated from the observation image of the first side shown.

[0542] Next, using the image processing software "ImageJ 1.52e" and "Fiji", the appropriate and inappropriate coordination numbers were determined for each of the 16 observed images. Then, for each of the 16 observed images, the appropriate coordination parameter was calculated by subtracting the inappropriate coordination number from the appropriate coordination number. The largest and smallest appropriate coordination parameters were then removed from the calculated values ​​of the 16 appropriate coordination parameters for each of the 16 observed images, resulting in 14 calculated values ​​for the appropriate coordination parameters. The appropriate coordination parameter for each example was calculated as the arithmetic mean of these 14 values. The calculated appropriate coordination parameters for each example are shown in the "Appropriate Coordination Parameter" column of Table 2.

[0543] The standard deviation of the appropriate coordination parameter for each example was calculated as the standard deviation of the calculated values ​​of the 14 appropriate coordination parameters. The standard deviation of the appropriate coordination parameter for each example is shown in the "Standard Deviation" column of Table 2.

[0544] <<2-5. Sensory Evaluation of Anti-glare Performance>>

[0545] A 10cm × 5cm sample was cut from the optical sheet of the examples and comparative examples. A black plate, manufactured by Kuraray and labeled "COMOGLASS K, Color Code: 502K (2mm thickness)," was bonded to the second side of the sample, which was used as the evaluation object for each example, using an optically clear adhesive. Visual inspection confirmed that the first side of the evaluation sample, prepared by sealing the black resin plate, was free of dust, scratches, or other abnormalities.

[0546] In a brightly lit room, the first surface of the evaluation sample was observed from various directions to confirm whether any hue was observed. The light-emitting part of the lighting device was an Hf32-type straight-tube three-wavelength daylight fluorescent lamp. The lighting device was positioned at a height of 2m vertically above the floor. The illuminance on the first surface of the evaluation sample was between 500 lux and 1000 lux. The evaluators' line of sight was approximately 170cm from the floor. The evaluators were 20 healthy individuals around 30 years old with visual acuity of 0.7 or better.

[0547] The observations were evaluated according to the following evaluation criteria. The evaluation results are shown in the "Tone" column of Tables 1 and 2. Ratings "AA" and "A" indicate the degree to which the product is considered acceptable in routine product inspections. A rating "B" indicates the degree to which the product is considered unacceptable in routine product inspections.

[0548] <Evaluation Criteria>

[0549] AA: There are fewer than 2 evaluators who can observe the hue in the evaluated sample.

[0550] A: The number of evaluators who can observe the hue in the evaluated sample is between 3 and 7.

[0551] B: There are more than 8 evaluators who can observe the hue in the evaluation sample.

[0552] [Table 1]

[0553] [Table 2]

[0554] Explanation of reference numerals in the attached figures

[0555] D1: First direction, D2: Second direction, D3: Third direction, 5: Sheet article, 6: Winding core, 7: Roll, RA: Winding axis, 10: Optical sheet, 11: First surface, 11X: Concave-convex surface, 12: Second surface, 20: Substrate, 30: Anti-glare layer, 31: First surface, 31X: Concave-convex surface, 31A: Reference part, 31B: Protrusion, 32: Second surface, 36: Resin, 37: Particles, 40: Functional layer, 46: Adhesive component, 47: Hollow silica particles, 50: Second functional layer, 60: Polarizer, 61: First protective sheet, 62: Polarizing element, 63: Second protective sheet, 65: Display device, 66: Display element, 66a: Image forming surface, 70: Panel, 71: Article to be bonded.

Claims

1. An optical sheet comprising a first surface and a second surface opposite each other in a first direction, wherein, The optical sheet comprises an anti-glare layer and a functional layer in order from the second surface toward the first surface. The transmission haze of the optical sheet is above 10% and below 70%. The functional layer comprises an adhesive component and hollow silica particles. Based on the observation on the first surface, the appropriate coordination parameter of the hollow silica particles is above 1.0 and below 2.

0. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a hollow silica particle. The inappropriate coordination number is the number of other hollow silica particles whose centroids are located at a distance of less than 55 nm from the centroid of the hollow silica particle.

2. The optical sheet according to claim 1, wherein, Measured using the reflected light from the first surface Color system Values ​​above -4.0 and below 4.0 Measured using the reflected light from the first surface Color system Values ​​are above -4.0 and below 4.

0.

3. The optical sheet according to claim 1, wherein, The standard deviation of the appropriate coordination parameter is below 0.

30.

4. The optical sheet according to claim 1, wherein, The apparent reflectance of the first surface is compared with that measured using reflected light. Color system The absolute value of the product of values ​​is less than 4.

0. The visual reflectance and the reflectance measured using reflected light Color system The absolute value of the product of values ​​is less than 4.

0.

5. The optical sheet according to claim 1, wherein, The visual reflectance of the first surface is less than 2.0%.

6. The optical sheet according to claim 1, wherein, The anti-glare layer includes uneven surfaces. The concave-convex surface is closer to the first surface in the first direction than the second surface. The concave-convex surface includes a reference portion and a protrusion protruding from the reference portion. The appropriate coordination parameter is a value measured in the region of the first surface opposite to the reference part in the first direction.

7. The optical sheet according to claim 1, wherein, The anti-glare layer comprises resin and particles. The appropriate coordination parameter is a value measured in the region on the first surface opposite the region of the anti-glare layer where the particles are absent in the first direction.

8. A sheet article comprising a plurality of optical sheets as described in any one of claims 1 to 7.

9. The sheet article according to claim 8, which is wound around a winding axis.

10. A panel comprising the optical sheet according to any one of claims 1 to 7.

11. A polarizer comprising an optical sheet according to any one of claims 1 to 7 and a polarizing element overlapping the optical sheet.

12. A display device comprising an optical sheet according to any one of claims 1 to 7 and a display element overlapping the optical sheet.

13. A method for selecting an optical sheet, comprising the following steps: For an optical sheet, the step of determining appropriate coordination parameters based on hollow silica particles observed on a first surface, the optical sheet comprising a first surface and a second surface opposite each other in a first direction, and including an anti-glare layer and a functional layer in order from the second surface toward the first surface, the optical sheet having a transmission haze of 10% or more and 70% or less, the functional layer comprising an adhesive component and the hollow silica particles; and The steps for selecting an optical sheet with a suitable coordination parameter of 1.0 or higher and 2.0 or lower. The appropriate coordination parameter is the value obtained by subtracting the inappropriate coordination number from the appropriate coordination number. The appropriate coordination number is the number of hollow silica particles whose centroids are located at a distance of more than 55 nm and less than 75 nm from the centroid of a single hollow silica particle. The inappropriate coordination number is the number of hollow silica particles whose center of gravity is located at a distance of less than 55 nm from the center of gravity of the hollow silica particle.

14. A method for manufacturing an optical sheet, comprising the following steps: The steps for manufacturing the optical sheet; and The step of selecting the optical sheet using the selection method described in claim 13.

Images