JP6500495B2 - Touch panel, display device, optical sheet, method of sorting optical sheet, and method of manufacturing optical sheet - Google Patents

Description

  The present invention relates to a touch panel, a display device, an optical sheet, a method of sorting an optical sheet, and a method of manufacturing an optical sheet.

In recent years, mobile information terminal equipment equipped with a tablet PC and a two-way communication function represented by a smartphone and equipped with a transparent touch panel for displaying information and inputting information has begun to spread widely not only in Japan but also in the world Came.
As a transparent touch panel, there is a resistive film method that is excellent in cost, but it is possible to perform gesture operations such as multi-touch, etc., and it is difficult to impair the image quality of a display element with ultra-high definition. The demand for touch panels of the type, in particular, of touch panels of projected capacitive type, is increasing.

An antiglare sheet having a concavo-convex structure may be installed on the surface of the touch panel for the purpose of preventing reflection of external light and the like.
Furthermore, the outermost surface substrate, the inner substrate, and the rearmost surface of the touch panel for the purpose of preventing adhesion between members forming the touch panel and interference fringes, and adhesion and interference fringes between the touch panel and the display element. An optical sheet having an uneven structure may be used as a substrate or the like.

However, in the case of using an optical sheet having a concavo-convex structure such as an antiglare film, a phenomenon (glare) in which minute variations in luminance appear in the image light occurs due to the concavo-convex structure, and the display quality is degraded. There's a problem. In particular, the glare problem is further aggravated in the recent ultra-high definition display elements (pixel density of 300 ppi or more).
The techniques of Patent Documents 1 to 9 have been proposed as techniques for preventing glare due to surface irregularities.

JP 2003-302506 Japanese Patent Application Publication No. 2002-267818 JP, 2009-288650, A JP, 2009-86410, A JP, 2009-128393, A Japanese Patent Application Laid-Open No. 2002-196117 International Publication No. 2007/111026 JP, 2008-158536, A JP, 2011-253106, A

  The optical sheets of Patent Documents 1 and 2 improve glare by providing an internal haze. However, ultra high definition display devices having a pixel density of 300 ppi or more tend to have a strong glare, and if the glare is to be suppressed only by the internal haze, the internal haze must be further increased. In addition, when the internal haze is large, the resolution tends to deteriorate, but the tendency is higher in the ultra-high definition display element. Therefore, even if attention is focused only on internal haze as in Patent Documents 1 and 2, it has not been possible to obtain an optical sheet suitable for an ultra-high definition display element having a pixel density of 300 ppi or more.

  The optical sheets of Patent Documents 3 to 9 improve glare by lowering the inclination angle of the unevenness to weaken the degree of the unevenness. However, even with the optical sheets of Patent Documents 3 to 9, it was not possible to prevent the glare of the ultra-high definition display element having a pixel density of 300 ppi or more. Moreover, the optical sheet of patent documents 3-9 reduced the level of anti-glare property.

  The present invention has been made under such circumstances, and a touch panel, a display device, and an optical sheet capable of preventing glare of image light of an ultrahigh definition display element having a pixel density of 300 ppi or more even when having a concavo-convex structure. Intended to provide. The present invention also provides a method of selecting and manufacturing an optical sheet for preventing glare of image light of an ultrahigh definition display device having a pixel density of 300 ppi or more.

MEANS TO SOLVE THE PROBLEM As a result of earnestly research, the present inventors discovered that the said subject could be solved by controlling the transmitted-image definition for every width | variety of the optical comb of JISK7374 to specific relationship.
Means of Solving the Problems The present invention provides the following touch panel, display device, optical sheet, and method of sorting optical sheets and method of producing optical sheets according to the following [1] to [9].

[1] A touch panel having an optical sheet as a component, wherein the optical sheet has an uneven shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm in accordance with JIS K7374. The transmission image definition of the optical sheet is measured for each of 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and the transmission image definition with an optical comb width of 0.125 mm is C _0.125 , Optical comb width 0.25 mm transmission image sharpness C _0.25 , optical comb width 0.5 mm transmission image sharpness C _0.5 , optical comb width 1.0 mm transmission image sharp A display element with a pixel density of 300 ppi or more, satisfying the following conditions (1) and (2), where C _{1.0 is} the degree of light transmission, and C _2.0 is the transmitted image definition with a width of the optical comb of 2.0 mm Touch panel used on the front of the.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.
[2] The touch panel according to the above [1], wherein the three-dimensional average surface roughness SRa of the uneven surface of the optical sheet is 0.100 μm or more.
[3] The touch panel according to the above [1] or [2], wherein the haze of the optical sheet is 15 to 40%.

[4] A display device having an optical sheet on the front surface of a display element having a pixel density of 300 ppi or more, wherein the optical sheet has a concavo-convex shape on the surface and conforms to JIS K7374. Measure the transmitted image definition of the optical sheet for each of the width of the optical comb of the measuring instrument is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, the width of the optical comb is 0.125 mm Transmission image sharpness C _0.125 , optical comb width 0.25 mm transmission image sharpness C _0.25 , optical comb width 0.5 mm transmission image sharpness C _0.5 , optical Assuming that the transmission image definition with a comb width of 1.0 mm is C _1.0 and the transmission image definition with an optical comb width of 2.0 mm is C _2.0 , the following conditions (1) and (2) The display device that meets).
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.
[5] An optical sheet having a concavo-convex shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2. in accordance with JIS K7374. The transmitted image definition of the optical sheet is measured for each of 0 mm, the transmitted image definition with an optical comb width of 0.125 mm is C _0.125 , and the transmitted image _{definition with} an optical comb width of 0.25 mm is C _0.25 , optical comb width 0.5 mm transmission image clarity C _0.5 , optical comb width 1.0 mm transmission image sharpness C _1.0 , optical comb width 2.0 mm An optical sheet used on the front surface of a display element having a pixel density of 300 ppi or more, satisfying the following conditions (1) and (2), when the transmitted image definition of is C _2.0 .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.
[6] The optical sheet according to [5], wherein the three-dimensional average surface roughness SRa of the surface of the uneven shape of the optical sheet is 0.100 μm or more.
[7] The optical sheet according to the above [5] or [6], wherein the optical sheet has an internal haze of 15 to 40%.

[8] A method of sorting an optical sheet having a concavo-convex shape on the surface, wherein the width of the optical comb of the image clarity measuring instrument is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm in accordance with JIS K7374. And the transmission image clarity of the optical sheet was measured for each of 2.0 mm, and the transmission image sharpness of the optical comb width of 0.125 mm was C _0.125 and the transmission image sharpness of the optical comb width of 0.25 mm C _0.25 , the optical image width of the optical comb is 0.5 mm, the transmitted image clarity C _0.5 , the optical image width of the optical comb is 1.0 mm, the transmitted image image definition C _1.0 , the optical comb width is Used as the front face of a display element with a pixel density of 300 ppi or more, which selects an optical sheet that satisfies the following conditions (1) and (2) when the transmitted image definition of 2.0 mm is C _2.0 Optical sheet sorting method.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.
[9] A method for producing an optical sheet having a concavo-convex shape on the surface, wherein the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm according to JIS K7374. And the transmission image clarity of the optical sheet was measured for each of 2.0 mm, and the transmission image sharpness of the optical comb width of 0.125 mm was C _0.125 and the transmission image sharpness of the optical comb width of 0.25 mm C _0.25 , the optical image width of the optical comb is 0.5 mm, the transmitted image clarity C _0.5 , the optical image width of the optical comb is 1.0 mm, the transmitted image image definition C _1.0 , the optical comb width is An optical sheet used on the front surface of a display element having a pixel density of 300 ppi or more manufactured so as to satisfy the following conditions (1) and (2) when the transmission image definition of 2.0 mm is C _2.0 Production method.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

The touch panel, the display device, and the optical sheet of the present invention can impart various characteristics such as antiglare property by the concavo-convex shape, and can prevent the glare of the image light of the ultrahigh definition display element having a pixel density of 300 ppi or more.
Further, according to the method of evaluating an optical sheet of the present invention, glare can be evaluated without incorporating the optical sheet in the display device, and the quality control of the optical sheet can be efficiently performed. Further, the method of manufacturing an optical sheet according to the present invention can efficiently manufacture an optical sheet capable of preventing glare of image light of a display element of ultra high definition having a pixel density of 300 ppi or more.

It is sectional drawing which shows one Embodiment of the resistive film type touch panel of this invention. It is a sectional view showing one embodiment of a capacitive touch panel of the present invention. 2 is a scanning transmission electron micrograph (STEM) showing a cross section of the optical sheet of Example 1. FIG.

Hereinafter, embodiments of the present invention will be described.
[Touch panel]
The touch panel according to the present invention is a touch panel having an optical sheet as a component, wherein the optical sheet has an uneven shape on the surface, and the width of the optical comb of the image clarity measuring device conforms to JIS K7374. 0.125mm, 0.25mm, 0.5mm, for each of 1.0mm and 2.0mm were measured transmission image clarity of the optical sheet, _{C 0} the transmission image clarity of the width of the optical comb is 0.125mm _.125 , optical comb width 0.25 mm transmission image sharpness C _0.25 , optical comb width 0.5 mm transmission image sharpness C _0.5 , optical comb width 1.0 mm A pixel density of 300 ppi or more satisfying the following conditions (1) and (2), where C _1.0 is the transmission image definition and C _2.0 is the transmission image definition with an optical comb width of 2.0 mm. Used in front of the display element of .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

Examples of the touch panel include a capacitive touch panel, a resistive touch panel, an optical touch panel, an ultrasonic touch panel, and an electromagnetic induction touch panel. These touch panels have substrates such as a glass substrate and a plastic film substrate, and an uneven shape for imparting various properties such as antiglare property, adhesion prevention and interference fringes prevention on the surface of the substrate. May be formed. The touch panel of the present invention is formed by using an optical sheet to be described later as a substrate having an uneven shape on such a surface.
When providing a touch panel with antiglare properties, it is preferable to use an optical sheet to be described later as a surface member of the touch panel, and to set the surface of the optical sheet on the uneven side to face the surface side.

  The resistive film type touch panel 1 is not illustrated in the basic configuration in which the conductive films 12 of the pair of upper and lower transparent substrates 11 having the conductive films 12 are disposed via the spacer 13 so as to face each other as shown in FIG. A circuit is connected. In the case of a resistive film type touch panel, it is preferable to use an optical sheet described later as the upper transparent substrate and / or the lower transparent substrate. The upper transparent substrate and the lower transparent substrate may have an optical sheet, which will be described later, as one of the substrates, as a multilayer structure including two or more substrates.

If the optical sheet in the resistive film type touch panel is used as an upper transparent substrate, for example, using an optical sheet to be described later and the concave and convex surface of the optical sheet faces the opposite side to the lower transparent substrate, While being able to provide the property, it is possible to prevent glare of the ultra-high definition display element and to prevent the reduction of the resolution of the ultra-high definition display element. Moreover, in the case of this usage, it is preferable from the point which can make it hard to visually recognize the flaw which arose on the surface of a touch panel, a conductive film, etc., and can contribute to the improvement of a yield.
When an optical sheet to be described later is used as the upper transparent substrate so that the concavo-convex surface faces the lower transparent substrate side, glare of the ultra-high definition display element is prevented and the upper and lower conductive films adhere to each other at the time of operation. It is possible to prevent the occurrence of interference fringes due to the proximity of the upper and lower conductive films.
Also, by using an optical sheet to be described later as the lower transparent substrate of the resistive touch panel and by causing the uneven surface of the optical sheet to face the upper transparent substrate side, reflection of the surface of the lower electrode is suppressed and Glare of a fine display element can be prevented. Furthermore, in the case of this usage, the upper and lower conductive films can be prevented from adhering to each other at the time of operation, and interference fringes can be prevented from being generated due to the upper and lower conductive films coming close.
When an optical sheet, which will be described later, is used as the lower transparent substrate so that the concavo-convex surface faces the opposite side to the upper transparent substrate, it is preferable in that glare can be prevented and adhesion and interference fringes can be prevented.

The capacitive touch panel includes a surface type, a projection type, and the like, and a projection type is often used. The projection-type capacitive touch panel is formed by connecting a circuit to a basic configuration in which an X-axis electrode and a Y-axis electrode orthogonal to the X electrode are disposed via an insulator. More specifically describing the basic configuration, an embodiment in which an X electrode and a Y electrode are formed on different surfaces of one transparent substrate, and an X electrode, an insulator layer, and a Y electrode are formed in this order on the transparent substrate. 2, the X electrode 22 is formed on the transparent substrate 21, the Y electrode 23 is formed on another transparent substrate 21, and the layer is laminated via the adhesive layer 24 or the like. Be Moreover, the aspect which laminates | stacks a further another transparent substrate is mentioned to these basic modes.
In the case of a capacitive touch panel, it is preferable to use an optical sheet described later for at least one or more of the transparent substrates. In addition, you may use the optical sheet mentioned later as one base material among the transparent substrates as a multilayer structure which consists of a 2 or more base material.

When the capacitive touch panel is configured to have another transparent substrate on the above-described basic aspect, an optical sheet to be described later is used as the additional transparent substrate, and the uneven surface of the optical sheet is opposite to the basic aspect. When the uneven surface is directed to the operator side, it is possible to provide anti-glare property to the capacitive touch panel and to prevent glare of the ultra-high definition display element, and further, Can prevent the reduction of the resolution of the ultra-high definition display device. Moreover, in this case of use, it is preferable from the point which can make it hard to see the flaw which arose on the surface of a touch panel, a conductive film, etc., and an electrode pattern.
In the case where the capacitive touch panel has an X electrode formed on a transparent substrate, a Y electrode formed on another transparent substrate, and is laminated via an adhesive or the like, at least one transparent substrate will be described later. The same effect as described above can be obtained even in the case where the optical sheet including the optical sheet is used and the uneven surface of the optical sheet is directed to the operator side.
When an optical sheet to be described later is used as a transparent substrate of a capacitive touch panel so that the concavo-convex surface faces the opposite side to the operator, glare can be prevented and adhesion and interference fringes can be prevented, which is preferable. It is.

(Optical sheet)
The optical sheet used for the touch panel of the present invention has an uneven shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1 in accordance with JIS K7374. The transmission image clarity of the optical sheet is measured for each of 0. 0 mm and 2.0 mm, and the transmission image clarity with an optical comb width of 0.125 mm is C _0.125 transmission, and the optical comb width is 0.25 mm transmission. Image clarity C _0.25 , optical comb width 0.5 mm transmission image sharpness C _0.5 , optical comb width 1.0 mm transmission image sharpness C _1.0 , optical comb The following conditions (1) and (2) are satisfied when the transmitted image definition with a width of 2.0 mm is C _2.0 .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

The values of C _0.125 , C _0.25 , C _0.5 , C _1.0 and C _2.0 are considered to be affected by the inclination angle of the asperities. Here, when the level of the inclination angle of the unevenness is divided into five and the level 1 is the smallest inclination angle, C _0.125 is an inclination angle of level 1 or more, C _0.25 is an inclination angle of level 2 or more, C _0.5 is at an inclination angle of level 3 or higher, C _1.0 is an inclination angle at level 4 or higher, and C _2.0 is lower than 100% under the influence of an inclination angle of level 5 or higher it is conceivable that.
Satisfying the condition (1) indicates that the amounts of inclination angles of level 1 or more, inclination angles of level 2 or more, inclination angles of level 3 or more, and inclination angles of level 4 or more are almost constant. In other words, satisfying the condition (1) means that almost no inclination angle of level 3 or less exists in the concavities and convexities of the optical sheet, and most of the inclination angles are level 4. Then, assuming that the surface roughness does not greatly differ, the condition (1) is satisfied, and the inclination angle of most of the concavities and convexities of the optical sheet is set to the level 4 Will be small. Conversely, when the condition (1) is not satisfied, in addition to the unevenness of level 4, unevenness of levels 1 to 3 exists, and fine unevenness occurs in the unevenness of the surface of the optical sheet. Further, in a display element having a pixel density of 300 ppi or more, since the pixels are fine, uneven brightness is likely to occur due to the interaction between the image light and the minute variation of the unevenness.

In addition, satisfying the condition (2) means that the ratio of the tilt angle of level 5 or more to the tilt angle of levels 1 to 4 is small. Conversely, if the condition (2) is not satisfied, a large inclination angle of level 5 or more will exist. In addition, when the inclination angle is large, the influence on the glaring is large, and when the level is 5 or more, the tendency is considered to be remarkable.
Therefore, when the condition (2) is not satisfied, it is not possible to suppress glare by the large inclination angle of level 5 or more. On the other hand, it is thought that glare can be suppressed by satisfying the condition (2) and reducing the ratio of the inclination angle of level 5 or more. In addition, it is considered that the resolution can be improved by satisfying the condition (2) and reducing the ratio of the inclination angle of 5 or more.

The difference of the condition (1) is more preferably within 5.5%, further preferably within 4.0%.
The difference of the condition (2) is more preferably 11.0% or more, and still more preferably 11.5% or more. Condition (2) is preferably 20.0% or less in order to improve various properties to be imparted by the uneven shape such as antiglare property, adhesion prevention property, interference fringe prevention property and the like.

  The conditions (1) and (2) are preferably satisfied in substantially the entire area of the optical sheet. The entire area is set at almost the entire area, because the end of the optical sheet may cause a minute defect at the time of cutting or the like, and even if the end has a defect, it is difficult for a viewer to recognize as a defect. In addition, the area around the end of the optical sheet is a region that is difficult to visually recognize. For this reason, it is preferable to satisfy the conditions (1) and (2) in the area excluding 10 mm from the end of the four sides of the optical sheet. The same applies to conditions (3) to (4) described below and other parameters.

Moreover, in order to make the effects of the conditions (1) and (2) more easily exhibited, it is preferable to satisfy the following conditions (3) and (4).
Condition (3): C _0.125 is 30.0% or more.
Condition (4): C _2.0 is 40.0% or more.
As for the condition (3), C _0.125 is more preferably 35.0% or more, and still more preferably 40.0% or more. In addition, in order to make various properties provided with uneven | corrugated shapes, such as anti-glare property, close_contact | adherence prevention property, and interference fringe prevention property, favorable, it is preferable that C _0.125 is 50.0% or less.
As for the condition (4), C _2.0 is more preferably 50.0% or more, and still more preferably 55.0% or more. In addition, in order to make good the various performances provided with uneven | corrugated shapes, such as anti-glare property, adhesion prevention property, and interference fringe prevention property, it is preferable that C _2.0 is 70.0% or less.

In order to satisfy the conditions (1) to (4), it is preferable to reduce the variation in the asperity shape of the optical sheet. For example, the surface of the concavo-convex shape of the optical sheet is divided into measurement areas of a predetermined size, the three-dimensional arithmetic average roughness SRa in each measurement area is determined, and the three-dimensional arithmetic of all the measurement areas is calculated. This can be known by calculating the standard deviation σ _SRa of the average roughness.

In order to satisfy the conditions (1) to (4), it is preferable that the concavo-convex shape of the optical sheet satisfy the following condition (5).
Condition (5): The uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa in each measurement area is determined, and the standard deviation σ _SRa of the three-dimensional arithmetic average roughness in all measurement areas is calculated When the σ _SRa is 0.05 μm or less.

In the condition (5), σ _SRa indicates the degree of variation of the three-dimensional arithmetic average roughness SRa in each measurement area of 64 μm square. Since the size of 64 μm square corresponds to the size of the pixel of the color filter, if the unevenness degree in each area is dispersed, the unevenness of the brightness is easily generated due to the interference with the color filter.
Therefore, by setting the σ _SRa to 0.050 μm or less, the uneven brightness due to the interference between the pixel of the color filter and the uneven layer can be reduced, and the glare can be further suppressed.
The σ _SRa is preferably 0.040 μm or less, more preferably 0.030 μm or less.

In the present invention, SRa is a three-dimensional extension of the arithmetic mean roughness Ra of the two-dimensional roughness parameter described in JIS B0601: 1994. Assuming that a curved surface is Z (x, y) and the size of the reference surface is Lx and Ly, the following equation (a) is calculated.
(Wherein, A = Lx × Ly)
Further, assuming that the height at the position of the i-th point in the X-axis direction and the j-th point in the Y-axis direction is Zi _{, j} , the arithmetic mean roughness Sa is calculated by the following equation (b).
In addition, the reference plane at the time of calculating SRa in each area | region was used as the reference plane calculated | required by the whole measurement range instead of calculating | requiring a reference plane for every area | region.

In the measurement of the condition (5), a total of 100 or more measurement areas are provided. Moreover, each measurement area shall be made continuous and not spaced. Moreover, it is preferable to make each measurement area | region continue in two directions of the X direction and the Y direction orthogonal to this. For example, when the total number of measurement areas is 100, it is preferable to form 100 measurement areas from a 640 μm square area instead of forming 100 measurement areas from an area of 64 μm × 6400 μm.
The three-dimensional roughness surface is preferably measured using an interference microscope for the sake of simplicity. Examples of such an interference microscope include “New View” series manufactured by Zygo. In addition, SRa can be calculated by the measurement / analysis application software “MetroPro” attached to the above-mentioned interference microscope “New View” series.

The optical sheet used in the touch panel of the present invention preferably has a three-dimensional average surface roughness SRa of 0.100 μm or more on the surface of the uneven shape.
By setting SRa to 0.100 μm or more, it is possible to improve various performances to be imparted by the uneven shape such as the antiglare property, the adhesion preventing property, and the interference fringe preventing property. Further, by setting SRa to 0.100 μm or more, it is possible to make the shape of the electrode and the scratch of the optical sheet less noticeable.
From the viewpoint of antiglare property among the various performances, SRa is preferably 0.110 μm or more, and more preferably 0.115 μm.
When SRa is too large, the resolution and the contrast tend to decrease. Therefore, SRa is preferably 0.300 μm or less, more preferably 0.200 μm or less, and still more preferably 0.175 μm or less.
In the present invention, SRa is a value having a cutoff value of 0.8 mm.

  The optical sheet used in the touch panel according to the present invention can improve the antiglare property by the above-described concavo-convex shape, so it is not necessary to increase the internal haze more than necessary and prevent the reduction of the resolution of the ultra-high definition display device. Can.

  The optical sheet preferably has a total light transmittance of 80% or more, more preferably 85% or more, and still more preferably 90% or more according to JIS K7361-1: 1997.

  The optical sheet preferably has a haze of 25 to 60%, more preferably 30 to 60%, still more preferably 30 to 50% according to JIS K7136: 2000. By setting the haze to 25% or more, it is possible to impart antiglare properties and to make it difficult to see the shape and flaws of the electrode. Further, by setting the haze to 60% or less, it is possible to prevent a reduction in the resolution of the ultra-high definition display element and to easily prevent a reduction in the contrast.

When the haze is divided into surface haze (Hs) and internal haze (Hi), the surface haze is preferably 5 to 25%, more preferably 5 to 20%, and 7 to 15%. It is further preferred that By setting the surface haze to 5% or more, the antiglare property can be improved and the shape and flaws of the electrode can be made less visible. By setting the surface haze to 25% or less, the reduction in contrast and the reduction in resolution can be prevented. It is easy to do.
The internal haze is preferably 15 to 40%, more preferably 20 to 40%, and still more preferably 25 to 38%. By setting the internal haze to 15% or more, glare can be easily prevented by the synergetic action with the surface asperities, and by setting the internal haze to 40% or less, it is possible to prevent the reduction of the resolution of the ultrahigh definition display element.
The ratio (Hs / Hi) of the surface haze to the internal haze is preferably 0.1 to 0.5 from the viewpoint of the balance between the surface haze and the internal haze described above, 0.2 It is more preferable that it is -0.4.
The surface haze and the internal haze can be determined, for example, by the method described in the examples.

The above-mentioned optical sheet can be used without particular limitation as long as it has a concavo-convex shape satisfying at least one of the surfaces and satisfies the conditions (1) and (2) and has optical transparency. Moreover, although the uneven | corrugated shape which satisfy | fills conditions (1) and (2) may have on both surfaces of an optical sheet, the viewpoint of handleability and the visibility (resolution, whitening) of an image to one side And the other surface is preferably substantially smooth (Ra 0.02 μm or less).
The optical sheet may be a single layer of a concavo-convex layer, or may be a multilayer having a concavo-convex layer on a transparent substrate. The structure which has an uneven | corrugated layer on a transparent base material is suitable from handling property and the ease of manufacture.

  Examples of the method of forming the unevenness include 1) a method using an emboss roll, 2) etching treatment, 3) molding with a mold, 4) formation of a coating film by coating, and the like. Among these methods, molding by the mold of 3) is preferable from the viewpoint of reproducibility of the concavo-convex shape, and formation of a coating film by coating of 4) is preferable from the viewpoint of productivity and multi-variety correspondence.

  In molding by a mold, a mold having a shape complementary to the concavo-convex surface is produced, and after a material constituting the concavo-convex layer such as polymer resin or glass is poured into the mold and hardened, the mold is manufactured by taking out from the mold. be able to. When a transparent substrate is used, a polymer resin or the like is poured into a mold and the transparent substrate is superposed thereon, and then the polymer resin or the like is cured and manufactured by removing the transparent substrate from the mold. be able to.

The formation of a coating film by coating is carried out by applying a concavo-convex layer forming coating solution containing a binder resin and particles onto a transparent substrate by a known coating method such as gravure coating or bar coating, and optionally drying. It can be formed by curing.
In order to form the concavo-convex shape satisfying the conditions (1) and (2), it is preferable to contain organic particles and inorganic fine particles as particles in the concavo-convex layer forming coating solution. Thus, by containing different kinds of particles in the concavo-convex layer, it is considered that the variation in the surface shape of the concavo-convex layer is reduced, and the conditions (1) and (2) can be easily made into the above-mentioned range.

FIG. 3 is a scanning transmission electron micrograph showing a cross section of the concavo-convex layer of the optical sheet of Example 1, which is formed by coating a concavo-convex layer forming coating solution containing a binder resin, organic particles and inorganic fine particles. (STEM).
Usually, the surface of the uneven layer has a substantially smooth surface where no organic particles are present, but the uneven layer of FIG. 3 also has a gentle slope where the organic particles are not present. It is considered that this is because the inorganic fine particles affect the thixotropic properties of the coating solution and the drying characteristics of the solvent, and no leveling as usual occurs. Thus, by forming a gentle slope also in the place where organic particles do not exist, the variation in the surface shape of the concavo-convex layer is reduced, and it is considered that conditions (1) and (2) can be easily made into the above-mentioned range. Be

Examples of the organic particles include shapes such as spheres, disks, rugby balls, and indeterminate shapes, and hollow particles, porous particles, solid particles, and the like having these shapes. Among these, spherical solid particles are preferable from the viewpoint of antiglare.
Examples of organic particles include particles made of polymethyl methacrylate, acrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone resin, fluorine resin, polyester and the like. .
The organic particles are preferably non-hydrophilized organic particles whose surface is not hydrophilized. Since silica fine particles, which are a typical example of inorganic fine particles, have a high degree of hydrophilicity, organic particles and silica do not become dense in the uneven layer by using non-hydrophilized organic particles (for example, around organic particles) The silica is uniformly dispersed (without uneven distribution), and it is easy to reduce the variation of the surface shape of the concavo-convex layer.
Moreover, among the above-mentioned organic particles, acrylic-styrene copolymer particles and polystyrene particles are preferable, and polystyrene particles are more preferable. The acrylic-styrene copolymer particles and polystyrene particles have a small specific gravity and are hard to sink in the concavo-convex layer, so it is considered that the variation in the surface shape of the concavo-convex layer is reduced. In addition, since the polystyrene particles have a high degree of hydrophobicity, they are uniformly dispersed in the concavo-convex layer without being closely packed with the silica fine particles, which is a typical example of the inorganic particulates, and it is thought that the variation in the surface shape of the concavo-convex layer is reduced. In addition, the acryl-styrene copolymer particles are good in that control of the internal haze and aggregation / dispersion can be easily performed since control of the degree of refractive index and hydrophilicity is easy.

  Further, from the viewpoint of reducing the variation in the surface shape of the concavo-convex layer, it is preferable that [specific gravity of organic particles / specific gravity of mixture of binder resin and inorganic fine particles] be less than 1.0.

The organic particles preferably have an average particle diameter of 2 to 10 μm, and more preferably 3 to 8 μm, from the viewpoint of reducing variations in the surface shape of the uneven layer.
The ratio of the average particle size of the organic particles to the thickness of the uneven layer (average particle size of the organic particles / thickness of the uneven layer) is 0.4 to 0. It is preferably 8 and more preferably 0.5 to 0.7.

The average particle size of the organic particles can be calculated by the following operations (1) to (3).
(1) A transmission observation image is taken of the optical sheet of the present invention with an optical microscope. The magnification is preferably 500 to 2,000 times.
(2) Arbitrary 10 particles are extracted from the observation image, the long diameter and the short diameter of each particle are measured, and the particle diameter of each particle is calculated from the average of the long diameter and the short diameter. The major diameter is the longest diameter on the screen of the individual particles. Further, the minor axis is a line segment perpendicular to the middle point of the line segment that constitutes the major axis, and refers to the distance between two points where the orthogonal segment intersects the particle.
(3) The same operation is performed five times on the observation image of another screen of the same sample, and the value obtained from the number average of the particle sizes of a total of 50 particles is taken as the average particle size of the organic particles.
The average primary particle size of the inorganic fine particles and the average particle size of the aggregates of the inorganic fine particles are first imaged by TEM or STEM of the cross section of the optical sheet of the present invention. After imaging, the average primary particle diameter of the inorganic fine particles and the average particle diameter of the aggregates of the inorganic fine particles can be calculated by performing the same method as the above (2) and (3). The acceleration voltage of TEM or STEM is preferably 10 kV to 30 kV, and the magnification is preferably 50,000 to 300,000 times.

  The content of the organic particles is preferably 2 to 25% by mass, and 5 to 20% by mass, in the total solid content forming the uneven layer, from the viewpoint of reducing the variation of the surface shape of the uneven layer. More preferably, the content is 6 to 12% by mass.

Examples of the inorganic fine particles include fine particles of silica, alumina, zirconia, titania and the like. By uniformly distributing the inorganic fine particles in the concavo-convex layer, it is possible to easily reduce the variation in the surface shape of the concavo-convex layer. In addition, it is preferable that the inorganic fine particles form aggregates in the concavo-convex layer, and the aggregates are distributed sparsely. The formation of aggregates of the inorganic fine particles further increases the effect of reducing the variation in the surface shape, and the sparse distribution of the aggregates makes it possible to reduce the influence of diffusion by the inorganic fine particles.
Among the above-mentioned inorganic fine particles, silica fine particles are preferable from the viewpoint of transparency and from the viewpoint of reducing the variation in the surface shape of the uneven layer.

“Distributed uniformly in the concavo-convex layer” means any cross-section where no organic particles in the thickness direction of the concavo-convex layer are observed under conditions of a magnification of 10,000 times with a transmission electron microscope such as TEM or STEM. When observing the area, when the area ratio of the silica fine particles in the 5 μm square observation area is measured in each cross section, the average value is M, and the standard deviation is S, S / M ≦ 0.1 It means that there is.
“Sparsely distributed aggregates in the concavo-convex layer” locally means that the inorganic fine particles are unevenly distributed, and when observed in the same manner as above, 0 When the area ratio of the silica fine particles in the observation area of 5 μm square is measured, when the average value is M and the standard deviation thereof is S, it means that S / M ≧ 0.2.
The distribution of such inorganic fine particles can be easily determined by cross-sectional electron microscope observation in the thickness direction of the uneven layer. For example, FIG. 3 is a cross-sectional STEM photograph of the optical sheet of Example 1, in which the lower light-colored area is the substrate and the dark-colored band-shaped area on the upper part of the substrate is the cross-section of the uneven layer. In the cross section of the uneven layer, the portion observed as black spots is an aggregate of inorganic fine particles (silica fine particles), and it can be clearly confirmed that the aggregate of silica fine particles is uniformly dispersed in the uneven layer. Moreover, the area ratio of the aggregate of inorganic fine particles can be calculated, for example, using image analysis software.

The inorganic fine particles are preferably surface treated. By the surface treatment of the inorganic fine particles, the distribution of the inorganic fine particles in the uneven layer can be easily controlled appropriately. Further, the chemical resistance and the saponification resistance of the inorganic fine particle itself can be improved.
In addition, in order to prevent the inorganic particles from being densely packed around the organic particles, “Mn” indicating the area ratio of the inorganic particles in the area outside the organic particles 500 nm away from the organic particles and excluding the organic particles, It is preferable that “Mf”, which indicates the area ratio of the inorganic fine particles in the region outside the circumference outside 500 nm from the above, satisfy the relationship of Mf / Mn ≧ 1.0. Mn and Mf can be calculated by microscopically observing a cross section in which the organic particles in the thickness direction of the concavo-convex layer are observed under a condition of a magnification of 10,000 times with a transmission electron microscope such as TEM or STEM.

The surface treatment is preferably a hydrophobization treatment to make the surface of the inorganic fine particles hydrophobic. As a hydrophobization process, the method etc. which process an inorganic fine particle with the silane compound which has acryl groups, such as a methyl group and an octyl group, are mentioned, for example.
For example, although hydroxyl groups (silanol groups) are present on the surface of the silica fine particles, the above-mentioned surface treatment reduces the hydroxyl groups on the surface of the silica fine particles and can prevent excessive aggregation of the silica fine particles. Uneven dispersion of the silica fine particles can be suppressed.

  When using silica fine particles as the inorganic fine particles, amorphous silica is preferable in order to suppress excessive aggregation. On the other hand, when the silica fine particles are crystalline silica, the Lewis acidity of the silica fine particles becomes strong due to lattice defects included in the crystal structure, and the silica fine particles may be excessively aggregated.

As the silica fine particles, for example, fumed silica is preferably used because it is easy to aggregate itself and to easily form aggregates in the range of the particle diameter described later.
Fumed silica refers to amorphous silica having a particle diameter of 200 nm or less and produced by a dry method, and is obtained by reacting volatile compounds containing silicon in the gas phase. Fumed silica can be produced, for example, by hydrolyzing a silicon compound such as SiCl _{4 in} a flame of oxygen and hydrogen, and includes AEROSIL R 805 (manufactured by Nippon Aerosil Co., Ltd.).

The content of the inorganic fine particles is not particularly limited, but it is preferably 1.0 to 15.0% by mass, and more preferably 2.0 to 10.0% by mass of the total solid content forming the concavo-convex layer. And 3.0 to 8.0% by mass is more preferable. By setting it as the said range, the variation of the surface shape of an uneven | corrugated layer can be made easy to reduce by control of leveling property and suppression of the polymerization shrinkage | contraction of an uneven | corrugated layer.
Further, the ratio of the content of the organic particles and the inorganic fine particles in the concavo-convex layer (the content of the organic particles / the content of the inorganic particulates) is 0.5 to 5 easily from the viewpoint of reducing the variation of the surface shape of the concavo-convex layer. It is preferable that it is 2.5, and it is more preferable that it is 0.8-2.2.

  The inorganic fine particles preferably have an average primary particle size of 1 to 100 nm. By setting the average primary particle diameter to 1 nm or more, suitable aggregates are easily formed, and by setting the average primary particle diameter to 100 nm or less, it is possible to suppress the decrease in contrast due to light diffusion and the excessive increase in internal haze. A more preferable lower limit is 5 nm, a more preferable upper limit is 50 nm, and a still more preferable upper limit is 20 nm.

It is preferable that the aggregate of the silica fine particles form a structure which is continuous in any direction as shown in the cross-sectional electron micrograph of FIG. By forming the aggregate in which the silica fine particles are continuous in an arbitrary direction in the concavo-convex layer, it is possible to easily form a uniform concavo-convex shape based on the organic particles.
The structure in which the silica fine particles are continuous in any direction is, for example, a structure (linear structure) in which the silica fine particles are continuously connected in a straight line, a structure in which plural linear structures are intertwined, and the above-mentioned linear structure Arbitrary structures, such as a branched structure which has one or two or more side chains in which the silica particle was formed in multiple numbers continuously, are mentioned.
It is preferable to use fumed silica in order to form an aggregate in which the silica fine particles are linked in an arbitrary direction as described above.

  The aggregate of the inorganic fine particles preferably has an average particle diameter of 100 nm to 1 μm. By setting the average particle diameter of the aggregates to 100 nm or more, the variation in the surface shape of the concavo-convex layer can be easily reduced, and by setting the average particle diameter to 1 μm or less, the decrease in contrast due to light diffusion can be suppressed. The more preferable lower limit of the average particle diameter of the aggregate is 200 nm, and the more preferable upper limit is 800 nm.

  The binder resin of the uneven layer preferably contains a thermosetting resin composition or an ionizing radiation curable resin composition, and from the viewpoint of improving mechanical strength, it is more preferable to include an ionizing radiation curable resin composition. Among these, it is more preferable to include an ultraviolet curable resin composition.

A thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition which is cured by heating.
As a thermosetting resin, an acrylic resin, a urethane resin, a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, a silicone resin etc. are mentioned. In the thermosetting resin composition, a curing agent is added to these curable resins as needed.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenic unsaturated bond groups such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group and oxetanyl group. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferable, and a compound having two or more ethylenically unsaturated bond groups is more preferable, and in particular, a compound having two or more ethylenically unsaturated bond groups, More preferred are polyfunctional (meth) acrylate compounds. As a polyfunctional (meth) acrylate type compound, any of a monomer and an oligomer can be used.
In the present specification, "(meth) acrylate" refers to methacrylate and acrylate.
Further, in the present specification, “ionizing radiation” means, among electromagnetic waves or charged particle beams, those having an energy quantum capable of polymerizing or crosslinking molecules, and generally, ultraviolet light (UV) or electron beam (EB) Although it is used, other than this, charged particle beams such as electromagnetic waves such as X-rays and γ-rays, α-rays and ion beams can also be used.

The ionizing radiation curable resin composition preferably contains 50% by mass or more, and more preferably 60% by mass or more of a polyfunctional (meth) acrylate compound having no hydroxyl group in the molecule.
When a solvent of high polarity (for example, isopropyl alcohol) is used as a solvent for the coating liquid for forming a concavo-convex layer by increasing the proportion of the polyfunctional (meth) acrylate compound containing no hydroxyl group in the molecule, The solvent can be easily evaporated, and excessive aggregation of the inorganic fine particles can be suppressed.

  As a polyfunctional (meth) acrylate type compound which does not contain a hydroxyl group in the molecule, for example, pentaerythritol tetraacrylate (PETTA), 1,6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), Tripropylene glycol diacrylate (TPGDA), PO modified neopentyl glycol diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate, dipentaerythritol hexaacrylate (DPHA), Pentaerythritol ethoxytetraacrylate, ditrimethylolpropane tetraacrylate and the like can be mentioned. Among them, pentaerythritol tetraacrylate (PETTA) is suitably used.

Other ionizing radiation curable compounds include compounds having one unsaturated bond such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, etc., and trimethylolpropane tri (meth) acrylate Tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, di Pentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca (meth) acrylate, isocyanuric acid tri (meth) acrylate, isocyanuric acid di (meth) acrylate, polyester tri (meth) acrylate, polyester Di (meth) acrylate, bisphenol di (meth) acrylate, diglycerin tetra (meth) acrylate, adamantyl di (meth) acrylate, isoboronyl di (meth) acrylate, dicyclopentadi (meth) acrylate, tricyclodecane di (meth) The compound which has two or more unsaturated bonds, such as an acrylate, is mentioned.
In the present invention, as the ionizing radiation curable compound, one obtained by modifying the above-mentioned compound with PO, EO or the like can also be used.

  Furthermore, as an ionizing radiation curable compound, relatively low molecular weight polyester resin having unsaturated double bond, polyether resin, acrylic resin, epoxy resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin Etc. can also be used.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains an additive such as a photopolymerization initiator or a photopolymerization accelerator.
Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoylbenzoate, α-acyloxime ester, thioxanthones and the like.
The photopolymerization initiator preferably has a melting point of 100 ° C. or more. By setting the melting point of the photopolymerization initiator to 100 ° C. or higher, the residual photopolymerization initiator is sublimated by the heat of the transparent conductive film formation or the crystallization process of the touch panel, and the resistance reduction of the transparent conductive film is impaired. Can be prevented.
Further, the photopolymerization accelerator can reduce the polymerization inhibition by air at the time of curing and can accelerate the curing rate, for example, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc. One or more types selected may be mentioned.

The thickness of the concavo-convex layer is preferably 2 to 10 μm, and more preferably 5 to 8 μm, from the viewpoint of curl suppression, mechanical strength, and balance with hardness and toughness.
The thickness of the uneven layer can be calculated, for example, by measuring the thickness at 20 locations from the image of the cross section taken using a scanning transmission electron microscope (STEM), and calculating the average value of the values at 20 locations. The acceleration voltage of the STEM is preferably 10 kV to 30 kV, and the magnification is preferably 1000 to 7000 times.

  In the coating solution for forming a concavo-convex layer, usually, a solvent is used to adjust the viscosity or to dissolve or disperse each component. Since the surface state of the uneven layer after coating and drying processes differs depending on the type of solvent, it is preferable to select the solvent in consideration of the saturated vapor pressure of the solvent, the permeability of the solvent to the transparent substrate, and the like. Specifically, the solvent is, for example, 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.), halogenated carbons (dichloromethane, dichloroethane etc.), esters (methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate etc.), alcohols (Butanol, cyclohexanol etc.), cellosolves (methyl cellosolve, ethyl cellosolve etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide etc.), amides (dimethylformamide, dimethylacetamide etc.) etc. , Or a mixture thereof.

When drying of the solvent is slow, the inorganic fine particles aggregate excessively in the concavo-convex layer, making it difficult to reduce the variation of the surface shape of the concavo-convex layer. In order to prevent excessive aggregation of the inorganic fine particles, it is preferable that the solvent contains a predetermined amount of one having high polarity and high volatilization speed.
In addition, since the solvent having high polarity and high volatilization speed volatilizes before the other solvents, the hydrophobicity around the organic fine particles becomes strong at the time of film formation. For this reason, by using a solvent having a high polarity and a high volatilization rate, it is possible to prevent the inorganic particles from being unevenly distributed around the organic particles, and the organic particles and the inorganic particles are uniformly dispersed without being concentrated in the uneven layer. it can.
In the present specification, the term "highly polar solvent" means a solvent having a solubility parameter of 10 [(cal / cm ³ ) ^1/2 ] or more, and the term "solvent with high evaporation rate" means a relative evaporation rate of 150. Means the above solvents.

The solubility parameter is calculated by the method of Fedors. The method of Fedors is described, for example, in "SP value basics / application and calculation method" (Hideki Yamamoto, published by Information Technology Co., Ltd., 2005). In the Fedors method, the solubility parameter is calculated by the following equation.
Solubility parameter = [ΣE _coh / ΣV] ²
In the above formula, E _coh is a cohesive energy density and V is a molar molecular volume. Based on the _{E coh} and V were determined for each atom _group, by determining the? En _coh and ΣV is the sum of _{E coh} and V, it is possible to calculate the solubility parameter.

In the present specification, "relative evaporation rate" refers to the relative evaporation rate when the evaporation rate of n-butyl acetate is 100, and is the evaporation rate measured according to ASTM D3539-87, calculated by the following equation Be done. Specifically, the evaporation time of n-butyl acetate under dry air at 25 ° C. and the evaporation time of each solvent are measured and calculated.
Relative evaporation rate = [(time taken for 90% by weight of n-butyl acetate to evaporate) / (time taken for 90% by weight of the measurement solvent to evaporate)] × 100

Examples of the solvent having high polarity and high volatilization speed include ethanol and isopropyl alcohol, among which isopropyl alcohol is preferable.
Moreover, it is preferable that content of the solvent with high polarity and quick volatilization speed is 10-40 mass% of all the solvent. By setting the content to 10% by mass or more, excessive aggregation of the inorganic fine particles can be easily suppressed, and by setting the content to 40% by mass or less, the volatilization of the solvent is too fast. It can control that it runs short.

  Further, from the viewpoint of facilitating obtaining the above-described concavo-convex shape, it is preferable to control the drying condition when forming the concavo-convex layer. The drying conditions can be adjusted by the drying temperature and the wind speed in the dryer. The specific drying temperature is preferably 30 to 120 ° C., and the drying speed is preferably 0.2 to 50 m / s. Further, in order to control the leveling of the concavo-convex layer according to the drying conditions, it is preferable to carry out the irradiation of ionizing radiation after the drying.

  Moreover, it is preferable to make the uneven | corrugated layer formation coating liquid contain a leveling agent from a viewpoint of making surface unevenness smooth moderately and obtaining the above-mentioned uneven | corrugated shape easily. As the leveling agent, fluorine-based or silicone-based ones can be mentioned, and a fluorine-based leveling agent that easily suppresses the formation of the Benard cell structure in the concavo-convex layer is preferable. The addition amount of the leveling agent is preferably 0.01 to 0.5% by weight, and more preferably 0.05 to 0.2% by weight, based on the total solid content of the coating solution for forming an uneven layer.

Moreover, the uneven | corrugated layer formation coating liquid mixes and disperse | distributes an inorganic fine particle to (2) intermediate composition after the process of mixing and stirring binder resin and organic particle to a solvent, and preparing an intermediate composition. It is preferable to prepare by performing.
By adjusting the uneven layer forming coating solution as described above, it is possible to easily suppress the variation in the surface shape of the uneven layer. On the other hand, in the case of the method different from the above adjustment (in the case where inorganic fine particles are added to the solvent before adding the organic particles and the binder resin), excessive aggregation of the inorganic fine particles occurs due to the solvent attack. It becomes difficult to reduce the variation of the surface shape.
In order to make the said effect more reliable, when adding an inorganic fine particle at a process (2), it is preferable that an inorganic fine particle is the inorganic fine particle dispersion which was disperse | distributed to the solvent.

  The transparent substrate of the optical sheet is preferably one having optical transparency, smoothness, heat resistance and excellent mechanical strength. As such a transparent substrate, polyester, triacetylcellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal And plastic films such as polyether ketone, poly (methyl methacrylate), polycarbonate, polyurethane and amorphous olefin (Cyclo-Olefin-Polymer: COP). The transparent substrate may be a laminate of two or more plastic films.

Among the above, from the viewpoint of mechanical strength and dimensional stability, stretch-processed, particularly biaxially-stretched polyester (polyethylene terephthalate, polyethylene naphthalate) is preferable.
TAC and acryl are preferable from the viewpoint of light transmissive optical isotropy. Further, TAC and acryl are easily dissolved by the solvent, and the dissolved TAC component and acryl component flow into the uneven layer, and have the function of pushing up the organic particles having a small specific gravity. That is, by using TAC and acryl as the transparent substrate, it is considered that the organic particles are less likely to sink in the concavo-convex layer, and it becomes easy to reduce the variation in the surface shape of the concavo-convex layer.
COP and polyester are preferable in that they have excellent weather resistance. In addition, a plastic film with a retardation value of 3000 to 300000 nm or a plastic film with a quarter wavelength retardation can prevent different colors from being observed on the display screen when the image of the liquid crystal display is observed through polarized sunglasses. It is suitable in point.

The thickness of the transparent substrate is preferably 5 to 300 μm, and more preferably 30 to 200 μm.
In addition to physical treatments such as corona discharge treatment and oxidation treatment, the surface of the transparent substrate may be coated beforehand with a paint called an anchor agent or a primer, in order to improve adhesion.

  The optical sheet may have a functional layer such as an antireflective layer, an antifouling layer, an antistatic layer or the like on the surface of the uneven surface and / or on the surface opposite to the uneven surface. Moreover, in the case of the structure which has an uneven | corrugated layer on a transparent base material, you may have a functional layer between a transparent base material and an uneven | corrugated layer other than the said location.

  The touch panel of the present invention can improve the antiglare property while imparting various characteristics such as antiglare property. In particular, by using the optical sheet as the surface member of the touch panel and disposing the surface of the optical sheet on the side of the uneven shape as the surface, it is preferable in that the antiglare property is easily provided while suppressing the reduction in contrast. It is.

[Display device]
The display device of the present invention is a display device having an optical sheet on the front surface of a display element having a pixel density of 300 ppi or more, wherein the optical sheet has an uneven shape on the surface and conforms to JIS K7374. Measure the transmitted image definition of the optical sheet for each of the width of the optical comb of the image clarity measuring instrument of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and the width of the optical comb 0.125 mm transmitted image sharpness C _0.125 , optical comb width 0.25 mm transmitted image sharpness C _0.25 , optical comb width 0.5 mm transmitted image sharpness C _{0 .5} , assuming that the transmission image sharpness of the optical comb is 1.0 mm in width C _1.0 and the transmission comb of the optical comb is 2.0 mm in width C _2.0 , the following conditions (1 And (2) are satisfied.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

Ultra-high definition display devices with a pixel density of 300 ppi or more are prone to glare as described above, but in the present invention, various characteristics such as antiglare properties are obtained by using a specific optical sheet as the optical sheet having a concavo-convex shape. Can be prevented while imparting
As an optical sheet used for the display apparatus of this invention, the thing similar to the optical sheet used for the touch panel of this invention mentioned above can be used.

Examples of the display element include a liquid crystal display element, an in-cell touch panel liquid crystal display element, an EL display element, and a plasma display element.
The in-cell touch panel liquid crystal element has a touch panel function such as a resistance film type, an electrostatic capacity type, or an optical type incorporated in a liquid crystal element formed by sandwiching a liquid crystal between two glass substrates. In addition, as a display method of the liquid crystal of an in-cell touch-panel liquid crystal element, an IPS system, VA system, a multi-domain system, OCB system, STN system, TSTN system etc. are mentioned. The in-cell touch panel liquid crystal element is described in, for example, JP-A-2011-76602 and JP-A-2011-222009.

The optical sheet can be placed, for example, in front of the display element in the following order.
(A) display element / surface protective plate / optical sheet (b) display element / optical sheet (c) touch panel having display element / optical sheet as a component (d) display element / optical sheet / surface protective plate (a) and In the case of (b), the antiglare property can be provided and glare can be prevented by arranging the optical sheet so that the uneven surface of the optical sheet faces the surface (the uneven surface faces the opposite side to the display element). Furthermore, it is possible to make it difficult to see scratches on the surface or display element.
In the case of (c), by arranging the optical sheet as in the embodiment of the touch panel of the present invention described above, it is possible to prevent glare while providing various characteristics such as antiglare property.
In addition, in the case of (b) and (d), if it arrange | positions via an air layer so that the uneven surface of an optical sheet may face the display element side, while preventing close_contact | adherence and interference fringes, the damage | wound produced in the display element It can be hard to see.
Portable information terminals represented by recent smartphones are often used outdoors. Therefore, in the display device of the present invention, it is preferable that the optical sheet be disposed on the outermost surface of the display device, and the uneven surface be used with the surface side (the opposite side to the display element) face.

[Optical sheet]
The optical sheet of the present invention is an optical sheet having a concavo-convex shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, according to JIS K7374. The transmitted image definition of the optical sheet was measured for each of 0 mm and 2.0 mm, and the transmitted image with a width of optical comb of 0.125 mm was 0.125 mm, the transmitted image of C _0.125 and the width of an optical comb was 0.25 mm Sharpness C _0.25 , Optical comb width 0.5 mm transmission image sharpness C _0.5 , Optical comb width 1.0 mm transmission image sharpness C _1.0 , Optical comb width Is a front surface of a display element having a pixel density of 300 ppi or more which satisfies the following conditions (1) and (2) when the transmission image sharpness of 2.0 mm is C _2.0 .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

As an optical sheet of this invention, the thing similar to the optical sheet used for the touch panel of this invention mentioned above is mentioned.
The optical sheet of the present invention is used on the front surface of a display element having a pixel density of 300 ppi or more, thereby preventing glare of an image light of an ultra-high definition display element and reduction in resolution while imparting various characteristics such as antiglare property. It is preferable at the point which can be done.
Portable information terminals represented by recent smartphones are often used outdoors. For this reason, it is preferable to use the optical sheet of the present invention such that the uneven surface faces the surface side (opposite to the display element) on the outermost surface of the touch panel or the display device.

[Method of sorting optical sheets]
The method of sorting optical sheets according to the present invention is a method of sorting optical sheets having an uneven shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm according to JIS K7374. The transmitted image clarity of the optical sheet was measured for each of 0.5 mm, 1.0 mm and 2.0 mm, the width of the optical comb was 0.125 mm, the transmitted image clarity was C _0.125 , and the width of the optical comb was A 0.25 mm transmission image sharpness C _0.25 , an optical comb width 0.5 mm transmission image sharpness C _0.5 , an optical comb width 1.0 mm transmission image sharpness C1 _{. 0 When} the transmitted image definition with an optical comb width of 2.0 mm is C _2.0 , a sheet satisfying the following conditions (1) and (2) is selected as an optical sheet, pixel density of 300 ppi or more Method of sorting optical sheets used in front of display device It is.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

  According to the method of sorting optical sheets of the present invention, it is possible to sort out optical sheets having excellent antiglare properties when used for ultra high definition display devices having a pixel density of 300 ppi or more without incorporating the optical sheets in the display device. Can efficiently control the quality of the optical sheet.

The determination conditions for sorting the optical sheet have the above (1) and (2) as essential conditions. The numerical range of the conditions (1) and (2) is preferably a suitable numerical range of the optical sheet described above. For example, in the judgment condition of the condition (1), it is preferable that the difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 5.5%. .

In the method of the present invention for sorting optical sheets, from the viewpoint of sorting optical sheets that can prevent glare more accurately, it is preferable to use the conditions (3) and (4) listed below as the determination conditions, and further listed below. It is more preferable to set conditions (3) to (6) as determination conditions. In addition to the conditions (3) and (4) or the conditions (3) to (6), it is more preferable to set the following condition (7) as a determination condition.
In addition, it is preferable that the numerical range of conditions (3)-(7) is a suitable numerical range of the optical sheet mentioned above.

Condition (3): C _0.125 is 30.0% or more.
Condition (4): C _2.0 is 40.0% or more.
Condition (5): The uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa in each measurement area is determined, and the standard deviation σ _SRa of the three-dimensional arithmetic average roughness in all measurement areas is calculated When the σ _SRa is 0.05 μm or less.
Condition (6): The three-dimensional average surface roughness SRa of the uneven surface is 0.100 μm or more.
Condition (7): The internal haze of the optical sheet is 15 to 40%.

[Method of manufacturing optical sheet]
The method for producing an optical sheet according to the present invention is a method for producing an optical sheet having a concavo-convex shape on the surface, and according to JIS K7374, the width of the optical comb of the image clarity measuring instrument is 0.125 mm, 0.25 mm, The transmitted image clarity of the optical sheet was measured for each of 0.5 mm, 1.0 mm and 2.0 mm, the width of the optical comb was 0.125 mm, the transmitted image clarity was C _0.125 , and the width of the optical comb was A 0.25 mm transmission image sharpness C _0.25 , an optical comb width 0.5 mm transmission image sharpness C _0.5 , an optical comb width 1.0 mm transmission image sharpness C1 _{. 0} A display element with a pixel density of 300 ppi or more manufactured so as to satisfy the following conditions (1) and (2), where C _2.0 is a transmitted image definition with an optical comb width of 2.0 mm: It is a manufacturing method of the optical sheet used for the front.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.

  In the method of manufacturing an optical sheet according to the present invention, it is possible to efficiently manufacture an optical sheet capable of imparting various characteristics such as antiglare property and preventing image light of an ultra-high definition display element having a pixel density of 300 ppi or more. it can.

In the method of manufacturing an optical sheet according to the present invention, it is essential to control the manufacturing conditions so as to satisfy the above conditions (1) and (2). The numerical range of the conditions (1) and (2) is preferably a suitable numerical range of the optical sheet described above. For example, in the condition (1), it is preferable that the difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 5.5%.

  In the method of manufacturing an optical sheet according to the present invention, it is preferable to control the manufacturing conditions so as to satisfy the conditions (3) and (4) of the method of selecting an optical sheet described above as additional conditions. It is more preferable to control the manufacturing conditions so as to satisfy the conditions (3) to (6) of the method. Furthermore, it is more preferable to satisfy the condition (7) while satisfying the conditions (3) and (4) or the conditions (3) to (6) of the method for selecting an optical sheet described above.

The manufacturing conditions (1) to (6) can be controlled by reducing the variation in the surface shape of the uneven layer.
As a specific means for controlling the manufacturing conditions (1) to (6), the shape of the mold may be controlled when the uneven layer is formed by the mold. In addition, specific means for controlling the production conditions (1) to (6) in the case of forming the concavo-convex layer by coating are organic particles, inorganic fine particles, binder resin, leveling agent, solvent, and preferred embodiments described above for drying conditions. It can be mentioned in the form.
The manufacturing conditions (7) can be controlled by the internal diffusion element. Specifically, the internal diffusion element can be controlled by adjusting the refractive index of the binder resin, the shape of the organic particles, the particle diameter of the organic particles, the addition amount of the organic particles, the refractive index of the organic particles, and the like. Further, the concentration and the like of materials (inorganic fine particles) other than the organic particles added to the binder resin also affect the internal diffusion factor.

  EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto. In addition, "part" and "%" make mass basis unless there is particular notice.

1. Physical Property Measurement and Evaluation of Optical Sheet The physical property measurement and evaluation of the optical sheets of Examples and Comparative Examples were performed as follows. The results are shown in Table 1.
1-1. Transmission Image Sharpness An optical image having a width of 0.125 mm, 0.25 mm, 0.5 mm, 1 mm and 2 mm according to JIS K7374 using an imageability measuring device (trade name: ICM-1T) manufactured by Suga Test Instruments Co., Ltd. Five types of transmission image sharpness through the comb were measured.

1-2. Concave-convex shape of optical sheet <SRa>
A white interference microscope (New) is attached to a glass plate via a transparent adhesive on the surface opposite to the surface on which the concavo-convex layer of each optical sheet obtained in Examples and Comparative Examples is formed. The surface shape of the optical sheet was measured and analyzed under the following conditions using View 7300 (manufactured by Zygo Corporation).
In addition, Microscope application of MetroPro ver 8.3.2 was used for measurement and analysis software.
(Measurement condition)
Objective lens: 50x Zoom: 1x Measurement area: 1mm x 1mm
Resolution (spacing per point): 0.44 μm
(Analysis conditions)
Removed: None
Filter: BandPass
FilterType: GaussSpline
Low wavelength: 800μm
High wavelength: 3 μm
Remove spikes: on
Spike Height (xRMS): 2.5
Low wavelength corresponds to the cutoff value λc in the roughness parameter.
The measurement data was divided into 12 4 12 areas (one area is 64 μm square), and SRa of each area was displayed on the Surface Map screen. Σ _SRa was calculated from SRa of each region. Further, the average value of SRa in each region was taken as SRa of the optical sheet of the example and the comparative example.

1-3. Haze First, using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory), the haze (overall haze) was measured according to JIS K-7136: 2000. In addition, by attaching a 80 μm thick TAC film (manufactured by Fujifilm Corporation, TD80UL) to the surface of the optical sheet via a transparent adhesive, the uneven shape is crushed and flattened, and the influence of the haze caused by the surface shape is eliminated. The haze was measured in the above state to determine the internal haze (Hi). Then, the internal haze value was subtracted from the overall haze value to determine the surface haze (Hs). The light incident surface was on the substrate side.

1-4. In each of the optical sheets obtained in Examples and Comparative Examples, the surface of the optical sheet on which the concavo-convex layer is not formed and the glass surface on which the black matrix (glass thickness 0.7 mm) is not formed are transparently adhered. It stuck with the medicine. Glare was generated in a pseudo manner by placing a white surface light source (LIGHTBOX manufactured by HAKUBA, average brightness: 1000 cd / m ² ) on the black matrix side of the sample thus obtained. This was photographed from the optical sheet side with a CCD camera (KP-M1, C mount adapter, close-up ring; PK-11A Nikon, camera lens; 50 mm, F1.4s NIKKOR). The distance between the CCD camera and the optical sheet was 250 mm, and the focus of the CCD camera was adjusted to fit the optical sheet. Images taken with a CCD camera were loaded into a personal computer and analyzed as follows using image processing software (ImagePro Plus ver. 6.2; manufactured by Media Cybernetics).
First, an evaluation portion of 200 × 160 pixels was selected from the captured image, and converted to 16-bit gray scale at the evaluation portion. Next, a low pass filter was selected from the emphasis tab of the filter command, and the filter was applied under the condition of "3 × 3, 3 times, 10 strength". This removed the component derived from the black matrix pattern. Next, flattening was selected, and shading correction was performed under the conditions of “background: dark, object width 10”. Next, contrast enhancement was performed with "contrast: 96, brightness: 48" in the contrast enhancement command. The resulting image was converted to 8-bit gray scale, and the glare was quantified by calculating the variation of the value for each pixel for 150 × 110 pixels among them as a standard deviation value. It can be said that the smaller the glaring value, the smaller the glaring value is. In addition, evaluation was performed by two, a black matrix corresponds to a pixel density of 350 ppi and a pixel equivalent to a pixel density of 200 ppi.

1-5. Antiglare property A sample for evaluation with a black acrylic plate pasted through a transparent adhesive on the substrate side of the obtained optical sheet was placed on a horizontal surface, and a fluorescent lamp was placed 1.5 m above the sample for evaluation. Under an environment in which a fluorescent lamp was transferred onto the evaluation sample and the illuminance on the evaluation sample was 800 to 1200 Lx, visual sensory evaluation was performed from various angles, and evaluation was performed according to the following criteria.
A: The image of the fluorescent lamp can not be recognized from any angle.
B: The image of the fluorescent light is reflected, but the outline of the fluorescent light is blurred, and the boundary of the outline can not be recognized.
C: The image of the fluorescent lamp is reflected like a mirror surface, and the contour of the fluorescent lamp (the boundary of the contour) can be clearly recognized.

1-6. A sample was prepared by bonding the surface on the transparent substrate side of the whitening optical sheet and a black acrylic plate through a transparent adhesive. About the produced sample, the cloudiness was observed on the following references | standards in the dark room under the desk lamp which used 3 wavelength fluorescent lamp tube as a light source.
A: Whiteness was not observed.
C: Whiteness was observed.
1-7. Interference fringes The two optical sheets were superimposed so that the uneven surface side of one optical sheet and the transparent base side of the other optical sheet faced each other. As a result, "A" indicates that no interference fringes occurred, and "C" indicates that interference fringes occurred.

2. Preparation of Irregular Layer Forming Coating Solution 2-1. Irregular layer forming coating solution 1
The formulations shown below were dispersed in a bead mill to obtain an intermediate composition. Subsequently, the composition shown below was dispersed by a bead mill to obtain an inorganic fine particle dispersion. Furthermore, while stirring the intermediate composition with a disper, the inorganic fine particle dispersion was gradually added to obtain a coating liquid 1 for forming an uneven layer.

(Intermediate composition)
Organic particles (non-hydrophilized polystyrene particles, average particle diameter 3.5 μm, refractive index 1.59, specific gravity 1.05, manufactured by Sekisui Plastics Co., Ltd.) 11 parts by mass pentaerythritol tetraacrylate (specific gravity 1.165) 60 parts by mass Urethane acrylate (trade name "V-4000BA", manufactured by DIC) 40 parts by mass Photopolymerization initiator (trade name "IRGACURE 184", manufactured by BASF Japan Ltd.) 5 parts by mass Polyether-modified silicone (product Name "TSF 4460", manufactured by Momentive Performance Materials Co., Ltd.) 0.025 parts by mass · toluene 100 parts by mass · isopropyl alcohol 40 parts by mass · propylene glycol monomethyl ether acetate 25 parts by mass

(Inorganic fine particle dispersion)
Fumed silica (Octylsilane treatment; average primary particle diameter 12 nm, specific gravity 2.00, manufactured by Nippon Aerosil Co., Ltd.) 7 parts by mass toluene 55 parts by mass isopropyl alcohol 20 parts by mass

2-2. Irregular layer forming coating solution 2
An uneven layer forming coating solution 2 was obtained in the same manner as the uneven layer forming coating solution 1 except that the compounding amount of the organic particles in the intermediate composition was 14 parts by mass.

2-3. Irregular layer forming coating solution 3
The uneven layer forming coating was carried out in the same manner as in the coating solution for forming an uneven layer, except that the blending amount of organic particles in the intermediate composition was 8 parts by mass, and the blending amount of fumed silica in the inorganic fine particle dispersion was 9 parts by mass. Liquid 3 was obtained.

2-4. Irregular layer forming coating solution 4
The organic particles in the intermediate composition have a blending amount of 12 as non-hydrophilized acrylic-styrene copolymer particles (average particle diameter 3.5 μm, refractive index 1.57, specific gravity 1.08, Sekisui Plastics Co., Ltd.) A concavo-convex layer forming coating liquid 4 was obtained in the same manner as in the concavo-convex layer forming coating liquid 1 except that it was used as a mass part.

2-5. Irregular layer forming coating solution 5
The compositions shown below were dispersed by a bead mill to obtain a composition 5 for an uneven layer.
Organic particles (non-hydrophilized polystyrene particles, average particle diameter 3.5 μm, refractive index 1.59, specific gravity 1.06, manufactured by Soken Chemical Co., Ltd.) 14 parts by mass Pentaerythritol triacrylate 100 parts by mass Acrylic polymer (molecular weight 75,000, manufactured by Mitsubishi Rayon 10 parts by weight Photopolymerization initiator (trade name “IRGACURE 184”, manufactured by BASF Japan Ltd.) 5 parts by weight Polyether-modified silicone (trade name “TSF 4460”, Momentive Performance Material 0.025 parts by mass, toluene 120 parts by mass, cyclohexanone 30 parts by mass

2-6. Irregular layer forming coating solution 6
Composition for an uneven layer except that the organic particles are non-hydrophilized acrylic-styrene copolymer particles (average particle diameter 3.5 μm, refractive index 1.57, specific gravity 1.08, manufactured by Sekisui Chemical Co., Ltd.) In the same manner as in the item 5, a composition 6 for an uneven layer was obtained.

2-7. Irregular layer forming coating solution 7
A composition for concavo-convex layer 7 was obtained in the same manner as the composition 5 for concavo-convex layer except that the organic particles were not blended.

3. Preparation of Optical Sheet [Example 1]
The concavo-convex layer forming coating solution 1 is applied on a transparent substrate (thickness 80 μm triacetyl cellulose resin film, manufactured by Fujifilm, TD 80 UL) and dried at 70 ° C. and a wind speed of 5 m / s for 30 seconds. Irradiation was performed so that the integrated light amount was 100 mJ / cm ² under (oxygen concentration: 200 ppm or less) to form a concavo-convex layer, to obtain an optical sheet. The film thickness of the uneven layer was 6.0 μm.

[Examples 2 to 4]
Optical sheets of Examples 2 to 4 were obtained in the same manner as Example 1, except that the concavo-convex layer forming coating liquid 1 was changed to the concavo-convex layer coating liquids 2 to 4.

Comparative Example 1
An optical sheet of Comparative Example 1 was obtained in the same manner as Example 1, except that the concavo-convex layer forming coating liquid 1 was used as the concavo-convex layer coating liquid 5 and the film thickness of the concavo-convex layer was 4.5 μm.

Comparative Example 2
An optical sheet of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the coating liquid 5 for forming an uneven layer was changed to the coating liquid 6 for forming an uneven layer.

Comparative Example 3
An optical sheet of Comparative Example 3 was obtained in the same manner as Comparative Example 1 except that the coating liquid 5 for forming an uneven layer was changed to the coating liquid 7 for forming an uneven layer.

As is clear from the results of Table 1, the optical sheets of Examples 1 to 4 can impart various characteristics such as antiglare properties and prevent glare of ultra-high definition display elements having a pixel density of 300 ppi or more. In addition, it was also excellent in contrast. In addition, the optical sheets of Examples 1 to 4 show an extremely better effect than the optical sheets of Comparative Examples 1 and 2 with regard to the antiglare property of the display element having a pixel density of 350 ppi. As for the antiglare performance of the element, the difference in the effect with the optical sheets of Comparative Examples 1 and 2 is reduced. From this, it can be seen that the optical sheets of Examples 1 to 4 are extremely useful for ultra-high definition display devices having a pixel density of 300 ppi or more.
In addition, although the thing of the comparative example 3 is excellent in antiglare property since it does not contain translucent particle | grains in an uneven | corrugated layer, while it is inferior to anti-glare property, an interference fringe generate | occur | produces and it can not use it. It was a thing.

4. Preparation of Touch Panel A conductive film of ITO having a thickness of 20 nm was formed by a sputtering method on the transparent substrate side of the optical sheets of Examples 1 to 4 and Comparative Examples 1 to 3 to form an upper electrode plate. Then, a conductive film of ITO having a thickness of about 20 nm was formed by sputtering on one surface of a 1 mm-thick tempered glass sheet to form a lower electrode plate. Next, after printing an ionizing radiation-curable resin (Dot Cure TR 5903: Taiyo Ink Co., Ltd.) as a coating liquid for spacers on the surface of the lower electrode plate having the conductive film in a dot pattern by a screen printing method, Irradiated, spacers 50 μm in diameter and 8 μm in height were arranged at intervals of 1 mm.
Next, the upper electrode plate and the lower electrode plate are disposed such that the conductive films face each other, and the edges are adhered with a double-sided adhesive tape of 30 μm in thickness and 3 mm in width, and Examples 1 to 4 and Comparative Examples 1 to 3 The resistive film type touch panel was manufactured.
The obtained resistive film type touch panel was placed on a commercially available ultra-high definition liquid crystal display (pixel density 350 ppi), and the presence or absence of glare was visually evaluated. There were also few reflections of external light, and the visibility was good. In addition, the touch panels of Examples 1 to 4 exhibited good contrast in a bright room environment without losing the resolution of the ultra high definition image. On the other hand, in the touch panels of Comparative Examples 1 and 2, glare was noticeable. In addition, the touch panel of the comparative example 3 reflected external light, and the visibility was not favorable.

5. Production of Display Device The optical sheets of Examples 1 to 4 and Comparative Examples 1 to 3 and a commercially available ultra-high definition liquid crystal display device (pixel density 350 ppi) are pasted together via a transparent adhesive, Examples 1 to 4 And the display apparatus of Comparative Examples 1-3 was produced. In addition, at the time of bonding, the uneven surface of the optical sheet was made to face the opposite side to the display element.
When the presence or absence of the glare of the obtained display was evaluated visually, the glare of the display of Examples 1-4 was suppressed, there were also little reflections of external light, and the visibility was favorable. In addition, the display devices of Examples 1 to 4 did not lose the resolution of the ultra high definition image, and the contrast in a bright room environment was also good. On the other hand, in the display devices of Comparative Examples 1 and 2, glare was noticeable. In addition, the display apparatus of the comparative example 3 had reflection of exterior light, and visibility was not favorable.

1: Resistive touch panel, 11: transparent substrate, 12: transparent conductive film, 13: spacer 2: capacitive touch panel, 21: transparent substrate, 22: transparent conductive film (X electrode), 23: transparent conductive film ( Y electrode), 24: adhesive layer

Claims (14)

It is a touch panel which has an optical sheet as a constituent member, and the optical sheet has a concavo-convex shape on the surface, and according to JIS K7374, the width of the optical comb of the image clarity measuring instrument is 0.125 mm, 0. 0 The transmission image clarity of the optical sheet was measured for each of 25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and the transmission width of the optical comb was 0.125 mm, the transmission image clarity was C _0.125 , the optical comb width _{C 0.25} the transmitted image clarity of 0.25mm is, _{C 0.5} a transmission image clarity of the width of the optical comb is 0.5 mm, the width of the optical comb is a transmission image clarity of 1.0 mm C _1.0, when the width of the optical comb is a transmission image clarity of 2.0mm and _{C 2.0,} meets the following conditions (1) and (2), size into the interior of the optical sheet 15 -40%, in front of display elements with a pixel density of 300 Touch panel used on the surface.
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more.   The touch panel according to claim 1, wherein the three-dimensional average surface roughness SRa of the surface of the uneven shape of the optical sheet is 0.100 μm or more. A display device comprising an optical sheet on the front surface of a display element having a pixel density of 300 ppi or more, wherein the optical sheet has a concavo-convex shape on the surface and is an image clarity measuring device according to JIS K7374. The transmission image clarity of the optical sheet is measured for each of the optical comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and the transmission image of the optical comb width of 0.125 mm Sharpness C _0.125 , optical comb width 0.25 mm transmission image sharpness C _0.25 , optical comb width 0.5 mm transmission image sharpness C _0.5 , optical comb width The following condition (1) and (2) is satisfied, where C _{1.0 is} a _1.0 mm transmitted image sharpness, and C _2.0 is a 2.0 mm wide transmitted light image sharpness. A display device having an internal haze of 15 to 40% .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more. An optical sheet having a concavo-convex shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm according to JIS K7374. The transmission image definition of the optical sheet is measured for the transmission sheet, the transmission image definition with an optical comb width of 0.125 mm C _0.125 , the transmission image _{definition with} an optical comb width 0.25 mm C _0.25 , Optical comb width 0.5 mm transmission image sharpness C _0.5 , optical comb width 1.0 mm transmission image sharpness C _1.0 , optical comb width 2.0 mm transmission image sharpness upon a _{C 2.0,} meets the following conditions (1) and (2), the front face of the size into the interior of the optical sheets is 15 to 40% pixel density 300ppi or more display elements Optical sheet used for
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more. The optical sheet according to claim 4 , wherein the three-dimensional average surface roughness SRa of the surface of the uneven shape of the optical sheet is 0.100 μm or more. 1. A method of sorting an optical sheet having an uneven shape on its surface, wherein the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2. in accordance with JIS K7374. The transmitted image definition of the optical sheet is measured for each of 0 mm, the transmitted image definition with an optical comb width of 0.125 mm is C _0.125 , and the transmitted image _{definition with} an optical comb width of 0.25 mm is C _0.25 , optical comb width 0.5 mm transmission image clarity C _0.5 , optical comb width 1.0 mm transmission image sharpness C _1.0 , optical comb width 2.0 mm the transmission image clarity of the time of the C _2.0, meets the following conditions (1) and (2), size into the interior of the optical sheet to screen what is 15% to 40% as an optical sheet , Optics used in front of display elements with a pixel density of 300 ppi or more How to sort sheets
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more. 1. A method of producing an optical sheet having a concavo-convex shape on its surface, wherein the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2. in accordance with JIS K7374. The transmitted image definition of the optical sheet is measured for each of 0 mm, the transmitted image definition with an optical comb width of 0.125 mm is C _0.125 , and the transmitted image _{definition with} an optical comb width of 0.25 mm is C _0.25 , optical comb width 0.5 mm transmission image clarity C _0.5 , optical comb width 1.0 mm transmission image sharpness C _1.0 , optical comb width 2.0 mm the transmission image clarity of the time of the C _2.0, meets the following conditions (1) and (2), size into the interior of the optical sheet is produced to an 15% to 40%, pixel density Method of manufacturing an optical sheet used in front of a display element of 300 ppi or more .
Condition (1): The difference between the maximum value and the minimum value of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%.
Condition (2): The difference between C _2.0 and C _1.0 is 10.0% or more. It is a touch panel which has an optical sheet as a constituent member, and the optical sheet has a concavo-convex shape on the surface, and in accordance with JIS K7374, the width of the optical comb of the image clarity measuring instrument is 0.125 mm, 0. 0. Measure the transmitted image definition of the optical sheet for each of 25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and set the transmitted image definition with an optical comb width of 0.125 mm _0.125 , C of transmitted image sharpness of 0.25 mm in width of optical comb _0.25 , C of transmitted image sharpness of 0.5 mm in width of optical comb _0.5 , C of transmitted image sharpness of optical comb width 1.0 mm _1.0 , C of transmitted image sharpness of 2.0 mm in width of optical comb _2.0 The touch panel used on the front surface of a display element having a pixel density of 300 ppi or more, satisfying the following conditions (1) to (4).
Condition (1): C _0.125 , C _0.25 , C _0.5 And C _1.0 The difference between the maximum value and the minimum value is within 6.0%.
Condition (2): C _2.0 And C _1.0 The difference with is 10.0% or more.
Condition (3): C _0.125 Is 30.0% or more.
Condition (4): C _2.0 Is 40.0% or more. The touch panel according to claim 8, wherein the three-dimensional average surface roughness SRa of the uneven surface of the optical sheet is 0.100 μm or more. A display device comprising an optical sheet on the front surface of a display element having a pixel density of 300 ppi or more, wherein the optical sheet has a concavo-convex shape on the surface and is an image clarity measuring device according to JIS K7374. The transmission image clarity of the optical sheet is measured for each of the optical comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, and the transmission image of the optical comb width of 0.125 mm C for clarity _0.125 , C of transmitted image sharpness of 0.25 mm in width of optical comb _0.25 , C of transmitted image sharpness of 0.5 mm in width of optical comb _0.5 , C of transmitted image sharpness of optical comb width 1.0 mm _1.0 , C of transmitted image sharpness of 2.0 mm in width of optical comb _2.0 And a display device satisfying the following conditions (1) to (4).
Condition (1): C _0.125 , C _0.25 , C _0.5 And C _1.0 The difference between the maximum value and the minimum value is within 6.0%.
Condition (2): C _2.0 And C _1.0 The difference with is 10.0% or more.
Condition (3): C _0.125 Is 30.0% or more.
Condition (4): C _2.0 Is 40.0% or more. An optical sheet having a concavo-convex shape on the surface, and the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm according to JIS K7374. The transmission image sharpness of the optical sheet is measured for the optical sheet, and the transmission comb is 0.125 mm in width of the optical comb. _0.125 , C of transmitted image sharpness of 0.25 mm in width of optical comb _0.25 , C of transmitted image sharpness of 0.5 mm in width of optical comb _0.5 , C of transmitted image sharpness of optical comb width 1.0 mm _1.0 , C of transmitted image sharpness of 2.0 mm in width of optical comb _2.0 The optical sheet used on the front surface of a display element having a pixel density of 300 ppi or more which satisfies the following conditions (1) to (4).
Condition (1): C _0.125 , C _0.25 , C _0.5 And C _1.0 The difference between the maximum value and the minimum value is within 6.0%.
Condition (2): C _2.0 And C _1.0 The difference with is 10.0% or more.
Condition (3): C _0.125 Is 30.0% or more.
Condition (4): C _2.0 Is 40.0% or more. The optical sheet according to claim 11, wherein a three-dimensional average surface roughness SRa of the surface of the concavo-convex shape of the optical sheet is 0.100 μm or more. 1. A method of sorting an optical sheet having an uneven shape on its surface, wherein the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2. in accordance with JIS K7374. Measure the transmitted image clarity of the optical sheet for each of 0 mm, and set the transmitted image clarity of the width of the optical comb to 0.125 mm. _0.125 , C of transmitted image sharpness of 0.25 mm in width of optical comb _0.25 , C of transmitted image sharpness of 0.5 mm in width of optical comb _0.5 , C of transmitted image sharpness of optical comb width 1.0 mm _1.0 , C of transmitted image sharpness of 2.0 mm in width of optical comb _2.0 The method of selecting an optical sheet to be used on the front surface of a display element having a pixel density of 300 ppi or more, which selects an optical sheet that satisfies the following conditions (1) to (4).
Condition (1): C _0.125 , C _0.25 , C _0.5 And C _1.0 The difference between the maximum value and the minimum value is within 6.0%.
Condition (2): C _2.0 And C _1.0 The difference with is 10.0% or more.
Condition (3): C _0.125 Is 30.0% or more.
Condition (4): C _2.0 Is 40.0% or more. 1. A method of producing an optical sheet having a concavo-convex shape on the surface, wherein the width of the optical comb of the image clarity measuring device is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2. in accordance with JIS K7374. Measure the transmitted image clarity of the optical sheet for each of 0 mm, and set the transmitted image clarity of the width of the optical comb to 0.125 mm. _0.125 , C of transmitted image sharpness of 0.25 mm in width of optical comb _0.25 , C of transmitted image sharpness of 0.5 mm in width of optical comb _0.5 , C of transmitted image sharpness of optical comb width 1.0 mm _1.0 , C of transmitted image sharpness of 2.0 mm in width of optical comb _2.0 When manufacturing, the manufacturing method of the optical sheet used for the front surface of a display element with a pixel density of 300 ppi or more manufactured so that the following conditions (1)-(4) may be satisfy | filled.
Condition (1): C _0.125 , C _0.25 , C _0.5 And C _1.0 The difference between the maximum value and the minimum value is within 6.0%.
Condition (2): C _2.0 And C _1.0 The difference with is 10.0% or more.
Condition (3): C _0.125 Is 30.0% or more.
Condition (4): C _2.0 Is 40.0% or more.