TWI693538B - Touch panel, display device, optical sheet and optical sheet screening method and optical sheet manufacturing method - Google Patents

Abstract

Provided is a touch panel that can impart anti-glare properties and other characteristics, and can prevent glare of image light of an ultra-high-definition display element with a pixel density of 300 ppi or more.

The touch panel has an optical sheet as a constituent member, the optical sheet has a concave-convex shape on the surface, and the optical sheet satisfies the following conditions A-1 and A-2, or satisfies the condition of specific transmission image clarity. The film is used on the front side of display elements with pixel density above 300ppi.

Condition A-1: When the above-mentioned uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa of each measurement area is calculated, and the standard deviation σ _SRa of the three-dimensional arithmetic average roughness of the entire measurement area is calculated , Σ _SRa is 0.050 μm or less.

Condition A-2: When the above-mentioned uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa of each measurement area is calculated, and the average SRA _AVE of the three-dimensional arithmetic average roughness of the entire measurement area is calculated, SRa _AVE is 0.100 μm or more.

Description

Touch panel, display device, optical sheet and optical sheet screening method and optical sheet manufacturing method

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

In recent years, mobile information terminal devices, which are represented by tablet PCs and smartphones and have a two-way communication function and are equipped with transparent touch panels for information display and information input, have not only spread widely in Japan but also in the world.

As a transparent touch panel, there is a cost-saving resistive film method, but in terms of gesture operations such as multi-touch, it is difficult to damage the image quality of ultra-high-definition display elements, etc., an electrostatic capacitance type touch panel , In particular, the demand for projection-type electrostatic capacitive touch panels continues to expand.

On the surface of the touch panel, in order to prevent reflection of external light, etc., an anti-glare sheet with an uneven structure is sometimes provided.

Furthermore, in order to prevent the adhesion and interference fringes between the components constituting the touch panel, and to prevent the adhesion and interference fringes between the touch panel and the display element, it is used as the outermost substrate, inner substrate, and rearmost surface of the touch panel For the base material and the like, an optical sheet having an uneven structure is sometimes used.

However, when using an optical sheet having an uneven structure such as an anti-glare film, Due to its uneven structure, there is a phenomenon that the fine brightness unevenness of the image light is visible (glare), resulting in a problem of degrading display quality. In particular, the glare problem is more serious in ultra-high-definition display devices (with a pixel density of 300 ppi or higher) in recent years.

As a technique for preventing glare caused by surface irregularities, techniques of Patent Documents 1 to 9 have been proposed.

Patent Document 1: Japanese Patent Laid-Open No. 2003-302506

Patent Document 2: Japanese Patent Application Publication No. 2002-267818

Patent Document 3: Japanese Patent Laid-Open No. 2009-288650

Patent Document 4: Japanese Patent Laid-Open No. 2009-86410

Patent Literature 5: Japanese Patent Laid-Open No. 2009-128393

Patent Literature 6: Japanese Patent Application Publication No. 2002-196117

Patent Literature 7: International Patent Publication No. 2007/111026

Patent Document 8: Japanese Patent Laid-Open No. 2008-158536

Patent Document 9: Japanese Patent Laid-Open No. 2011-253106

The optical sheets of Patent Documents 1 and 2 improve glare by imparting internal haze. However, ultra-high-definition display elements with a pixel density of 300 ppi or more have a tendency to increase glare, and if it is desired to suppress glare only by internal haze, the internal haze has to be further increased. In addition, when the internal haze is large, the resolution tends to deteriorate, which is more pronounced in ultra-high-definition display elements. Therefore, even if only focusing on the internal haze as in Patent Documents 1 and 2, an optical sheet suitable for an ultra-high-definition display element having a pixel density of 300 ppi or more cannot be obtained.

The optical sheets of Patent Documents 3 to 9 reduce the degree of unevenness by reducing the inclination angle of the unevenness, thereby improving glare. However, even the optical sheets of Patent Documents 3 to 9 cannot prevent glare of ultra-high-definition display elements with a pixel density of 300 ppi or more. In addition, the optical sheets of Patent Documents 3 to 9 reduce the level of anti-glare properties.

The present invention was completed under such circumstances, and its object is to provide a touch panel and display capable of preventing glare of image light of an ultra-high-definition display element with a pixel density of 300 ppi or more even when having a concave-convex structure Devices and optical sheets. In addition, the present invention provides a screening method and a manufacturing method of an optical sheet for preventing glare of image light of an ultra-high-definition display element having a pixel density of 300 ppi or more.

The inventors conducted intensive research and found that the concave-convex surface of the optical sheet was divided into 64 μm (64 μm equivalent to the mainstream of ultra-high-definition display elements, which is equivalent to the size of pixels of ultra-high-definition display elements) of 64 μm. The intermediate value of is 400 ppi), and the surface shape of each division is controlled to a specific shape, thereby solving the above problem.

The present invention provides the following [1] to [5] touch panels, display devices, optical sheets and optical sheet screening methods and optical sheet manufacturing methods.

[1] A touch panel having an optical sheet as a constituent member, the optical sheet having an uneven shape on the surface, and the optical sheet satisfying the following conditions A-1 and A-2, or satisfying the following conditions B-1 and B-2, the optical sheet is used for the front surface of the display element with a pixel density of 300ppi or more; condition A-1: dividing the surface of the above-mentioned concave-convex shape into 64μm square measurement areas, and calculating the three-dimensional arithmetic average roughness of each measurement area SRa, and when calculating the standard deviation σ _SRa of the three-dimensional arithmetic average roughness of the entire measurement area, σ _SRa is 0.050 μm or less; Condition A-2: After dividing the surface of the above-mentioned uneven shape into a measurement area of 64 μm square, find each When measuring the three-dimensional arithmetic average roughness SRa of the measurement area and calculating the average SRa _AVE of the three-dimensional arithmetic average roughness of the entire measurement area, the SRa _AVE is 0.100 μm or more; Condition B-1: According to JIS K7374, the image clarity (image clarity) ) The width of the optical comb of the measuring instrument is 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm, and the transmission image clearness of the optical sheet is measured; When the width is 0.125mm, the transmission image clarity is set to C _0.125 , when the width of the optical comb is 0.25mm, the transmission image clarity is set to C _0.25 , and when the width of the optical comb is 0.5mm, the transmission image clarity is set. For C _0.5 , set the transmission image clarity when the width of the optical comb is 1.0 mm to C _1.0 , and set the transmission image clarity when the width of the optical comb is 2.0 mm to C _2.0 , C _0.125 , C _0.25 , The difference between the maximum and minimum values of C _0.5 and C _1.0 is within 6.0%; Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more.

[2] A display device comprising an optical sheet on a front surface of a display element having a pixel density of 300 ppi or more, the optical sheet having a concave-convex shape on the surface, and the optical sheet satisfying the above conditions A-1 and A-2, or Satisfy the above conditions B-1 and B-2.

[3] An optical sheet having a concave-convex shape on the surface, the optical sheet satisfying the above conditions A-1 and A-2, or satisfying the above conditions B-1 and B-2, the optical sheet is used for pixels with a pixel density of 300 ppi or more The front of the display element.

[4] A screening method for optical sheets, which screens optical sheets having a concave-convex shape on the surface, the method screening for optical sheets satisfying the above conditions A-1 and A-2, or satisfying the above conditions B-1 and B-2 The optical sheet is used on the front of a display element with a pixel density of 300 ppi or more.

[5] A method of manufacturing an optical sheet, which is manufactured on an optical sheet having a concave-convex shape on its surface, such a method that the optical sheet satisfies the above conditions A-1 and A-2, or satisfies the above conditions B-1 and B-2 The optical sheet is manufactured in a manner that is used on the front side of a display element with a pixel density of 300 ppi or more.

The touch panel, the display device, and the optical sheet of the present invention can impart anti-glare properties and other characteristics through the uneven shape, and can prevent the glare of the image light of the ultra-high-definition display element having a pixel density of 300 ppi or more.

In addition, regarding the evaluation method of the optical sheet of the present invention, glare can be evaluated even if the optical sheet is not incorporated in the display device, and the quality of the optical sheet can be efficiently controlled. In addition, the method for manufacturing an optical sheet of the present invention can efficiently manufacture an optical sheet that can prevent glare of image light of an ultra-high-definition display element having a pixel density of 300 ppi or more.

1‧‧‧resistive film touch panel

2‧‧‧Electrostatic capacitive touch panel

11‧‧‧Transparent substrate

12‧‧‧Transparent conductive film

13‧‧‧ spacer

21‧‧‧Transparent substrate

22‧‧‧Transparent conductive film (X-axis electrode)

23‧‧‧Transparent conductive film (Y-axis electrode)

24‧‧‧ Adhesive layer

FIG. 1 is a cross-sectional view showing one embodiment of the resistive film touch panel of the present invention.

2 is a cross-sectional view showing an embodiment of an electrostatic capacitive touch panel of the present invention.

3 is a scanning transmission electron microscope photograph (STEM) showing the cross section of the optical sheet of Example 1. FIG.

Hereinafter, an embodiment of the present invention will be described.

[Touch Panel]

The touch panel of the present invention has an optical sheet as a constituent member, the optical sheet has an uneven shape on the surface, and the optical sheet satisfies the following conditions A-1 and A-2, or satisfies the following conditions B-1 and B-2 The optical sheet is used on the front of a display element with a pixel density of 300 ppi or more.

Condition A-1: When the above-mentioned uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa of each measurement area is calculated, and the standard deviation σ _SRa of the three-dimensional arithmetic average roughness of the entire measurement area is calculated , Σ _SRa is 0.050 μm or less.

Condition A-2: When the above-mentioned uneven surface is divided into 64 μm square measurement areas, the three-dimensional arithmetic average roughness SRa of each measurement area is calculated, and the average SRA _AVE of the three-dimensional arithmetic average roughness of the entire measurement area is calculated, SRa _AVE is 0.100 μm or more.

Condition B-1: According to JIS K7374, the transmission image clarity of the optical sheet is measured at the widths of the optical combs of the image clarity measuring device of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm. The transmission image clarity when the width of the optical comb is 0.125mm is set to C _0.125 , the transmission clarity when the width of the optical comb is 0.25mm is set to C _0.25 , and the transmission when the width of the optical comb is 0.5mm The image clarity is set to C _0.5 , the transmission image clarity when the width of the optical comb is 1.0 mm is set to C _1.0 , and the transmission image clarity when the width of the optical comb is 2.0 mm is set to C _2.0 , C _0.125 , C _0.25 , C _0.5 and C _1.0 The maximum and minimum difference is within 6.0%.

Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more.

Examples of touch panels include electrostatic capacitive touch panels, resistive film touch panels, optical touch panels, ultrasonic touch panels, and electromagnetic induction touch panels. Such touch panels have substrates such as glass substrates and plastic film substrates, and sometimes a concave-convex shape useful for imparting anti-glare properties, preventing adhesion, and preventing interference fringes and the like is formed on the surface of the substrate. The touch panel of the present invention is formed by using an optical sheet described later as a base material having an uneven shape on such a surface.

When imparting anti-glare properties to the touch panel, it is preferable to use an optical sheet described later as a surface member of the touch panel, and to provide the surface of the optical sheet on the concave-convex shape side toward the surface side.

As shown in FIG. 1, the resistive film type touch panel 1 is formed by connecting circuits not shown in the “basic configuration” as follows: the conductive films 12 having the next pair of transparent substrates 11 on the conductive film 12 face each other The method is arranged through the spacer 13. In the case of a resistive film touch panel, it is preferable to use the optical sheet described later as the upper transparent substrate and/or the lower transparent substrate. In addition, regarding the upper transparent substrate and the lower transparent substrate, as a multilayer structure composed of two or more base materials, an optical sheet described later may be used as one of the base materials.

For example, if the optical sheet of the resistive film type touch panel uses an optical sheet to be described later as the upper transparent substrate, and the concave and convex surface of the optical sheet is used to face the side opposite to the lower transparent substrate, the resistive film type touch panel can be protected Dazzling, and can prevent glare of ultra-high-definition display elements, and thus can prevent the resolution of ultra-high-definition display elements from decreasing. In addition, in the case of this method of use, it is difficult to observe the damage generated on the surface of the touch panel or the conductive film, which contributes to the improvement of the yield, which is more suitable in this respect.

Furthermore, when the optical sheet described later is used as the upper transparent substrate with the uneven surface facing the lower transparent substrate side, glare of the ultra-high-definition display element can be prevented, and the upper and lower conductive films can be prevented from adhering to each other during operation. Furthermore, interference fringes due to the proximity of the upper and lower conductive films are prevented.

In addition, by using an optical sheet described later as the lower transparent substrate of the resistive film type touch panel, and the concave and convex surfaces of the optical sheet are directed toward the upper transparent substrate side, surface reflection of the lower electrode can be suppressed, And can prevent glare of ultra-high-definition display elements. Furthermore, in the case of this method of use, it is possible to prevent the upper and lower conductive films from adhering to each other during operation, and to prevent interference fringes due to the proximity of the upper and lower conductive films.

In addition, when the optical sheet described later is used as the lower transparent substrate with the uneven surface facing the side opposite to the upper transparent substrate, glare can be prevented, and adhesion or interference fringes can be prevented, which is preferable in this respect.

The electrostatic capacitive touch panel may include a surface type and a projection type, and the projection type is often used. The projection-type electrostatic capacitive touch panel is formed by connecting circuits with the following "basic structure": an X-axis electrode and a Y-axis electrode orthogonal to the X-axis electrode are arranged through an insulator. If the basic configuration is described more specifically, the following may be mentioned: the X-axis electrode and the Y-axis electrode are formed on each surface of one transparent substrate; the X-axis electrode, the insulator layer, and the Y-axis electrode; as shown in FIG. 2, the X-axis electrode 22 is formed on the transparent substrate 21 and the Y-axis electrode 23 is formed on the other transparent substrate 21, and the layer is laminated via the adhesive layer 24 and the like. In addition, it can be mentioned in these basic aspects, in which another transparent substrate is laminated.

In the case of an electrostatic capacitive touch panel, it is preferable to use an optical sheet described later on at least one or more of the transparent substrates. In addition, the transparent substrate is a multilayer structure composed of two or more base materials, and an optical sheet described later may be used as one of the base materials.

The anti-glare property can be given to the electrostatic capacitive touch panel under the following circumstances, and the glare of the ultra-high-definition display element can be prevented, and thus the resolution of the ultra-high-definition display element can be prevented from decreasing: the electrostatic capacitive touch panel In the case where the above basic aspect further includes another transparent substrate, the optical sheet described later is used as the other transparent substrate, and the uneven surface of the optical sheet faces the side opposite to the above basic aspect, and the The uneven surface faces the operator's side. Again In the case of this method of use, damage to the surface of the touch panel and the conductive film, etc., and the shape of the electrode pattern are difficult to observe, which is more suitable in this respect.

In addition, in the following cases, the same effect as described above can also be obtained: the electrostatic capacitive touch panel is formed by forming an X-axis electrode on a transparent substrate, forming a Y-axis electrode on another transparent substrate, and laminating via an adhesive or the like In the case of the configuration, the one containing the optical sheet described later is used as at least one transparent substrate, and the uneven surface of the optical sheet is directed toward the operator.

Furthermore, when a transparent substrate as an electrostatic capacitance type touch panel is used with an optical sheet described later with the uneven surface facing the side opposite to the operator, glare can be prevented, and adhesion or interference fringes can be prevented. In terms of aspects, it is more appropriate.

(Optical sheet)

The optical sheet used in the touch panel of the present invention has an uneven shape on the surface, and satisfies the above conditions A-1 and A-2, or satisfies the above conditions B-1 and B-2.

The optical sheet only needs to satisfy the above conditions A-1 and A-2, or satisfy the above conditions B-1 and B-2, preferably satisfy the above conditions A-1 and A-2 and satisfy the above conditions B-1 and B- 2.

The σ _{SRa of} condition A-1 represents the degree of deviation of the three-dimensional arithmetic average roughness SRa of each measurement area of 64 μm square. Since the size of the 64 μm square corresponds to the size of the pixels of the color filter, if the unevenness of each area is not uniform, it is easy to produce uneven brightness due to interference with the color filter.

Therefore, by setting σ _SRa to 0.050 μm or less, it is possible to reduce the uneven brightness caused by the interference between the pixels of the color filter and the uneven layer, and it is easy to prevent glare.

σ _{SRa is} preferably 0.040 μm or less, and more preferably 0.030 μm or less.

SRa _{AVE in} Condition A-2 represents the degree of roughness of the irregular shape of the optical sheet. By setting SRa _AVE to 0.100 μm or more, it is possible to easily ensure various properties imparted by the uneven shape such as anti-glare properties, adhesion prevention properties, and interference fringe prevention properties. In addition, by setting SRa _AVE to 0.100 μm or more, the shape of the electrode or the damage of the optical sheet can be made inconspicuous.

From the viewpoint of anti-glare properties in the above-mentioned properties, SRa _{AVE is} preferably 0.110 μm or more, and more preferably 0.115 μm.

Furthermore, when SRa _{AVE is} too large, the resolution and contrast tend to decrease. Therefore, SRa _{AVE 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 set to a cutoff value of 0.8 mm.

Next, the condition B-1 will be described.

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 unevenness. Here, the level of the inclination of the unevenness is divided into five. When level 1 is set as the minimum angle of inclination, it can be considered that C _{0.125 is} affected by the angle of inclination above level 1, and C _{0.25 is} affected by the angle of inclination above level 2. The impact of C _{0.5 is} affected by the tilt angle of level 3 or higher, C _{1.0 is} affected by the tilt angle of level 4 or higher, and C _{2.0 is} affected by the tilt angle of level 5 or higher, but the value is not up to 100%.

Satisfying the condition B-1 indicates that the amount of the inclination angle above level 1, the inclination angle above level 2, the inclination angle above level 3, and the inclination angle above level 4 are substantially constant. In other words, satisfying the condition B-1 means that the unevenness of the optical sheet hardly has an inclination angle of grade 3 or lower, and most of the inclination angle is grade 4. Furthermore, it is considered that if the surface roughness is not significantly different, the unevenness of the unevenness in the surface of the optical sheet can be reduced by setting the inclination angle of the majority of the unevenness of the optical sheet to level 4, which can be easily Prevent glare.

The difference between the conditions B-1 is more preferably within 5.5%, and further preferably within 4.0%.

Satisfying condition B-2 means that the inclination angle of grade 5 or higher is less than the inclination angle of grades 1 to 4. It is considered that if the inclination angle is large, the influence on glare becomes large, and if it is at or above level 5, the tendency becomes significant.

Therefore, it is considered that by satisfying the condition B-2 (reducing the ratio of the inclination angle of grade 5 or more), glare can be easily prevented. Furthermore, it is considered that by satisfying the condition B-2, the ratio of the inclination angle of grade 5 or higher is reduced to improve the resolution.

In addition, by satisfying the conditions B-1 and B-2 at the same time, most of the inclination angles become grade 4, so that it is possible to easily ensure the anti-glare properties, adhesion prevention properties, interference fringe prevention properties, and other performances imparted by the uneven shape, Moreover, the shape of the electrode or the damage of the optical sheet is not obvious.

The difference between the conditions B-2 is more preferably 11.0% or more, and further preferably 11.5% or more.

In addition, in order to make each performance provided by the uneven shape such as anti-glare property, adhesion prevention property, interference fringe prevention property, etc., condition B-2 is preferably 20.0% or less.

As described above, satisfying the conditions A-1 and A-2 and satisfying the conditions B-1 and B-2 both mean that a certain level of unevenness is given, and the unevenness of the unevenness is small. It is preferable that substantially the entire area of the optical sheet satisfies the conditions A-1 and A-2 or the conditions B-1 and B-2. The reason why the entire area is set is that the end of the optical sheet may have minute defects during cutting, etc. Even if there is a defect at the end, it is difficult for the observer to recognize the defect. In addition, the periphery of the end of the optical sheet is an area that is difficult to visually confirm. Therefore, it is preferable that 95% or more of the area after removing 10 mm from the ends of the four sides of the optical sheet satisfy the conditions A-1 and A-2, or the conditions B-1 and B-2, and more preferably 97% of the area % Or more is satisfied, and more preferably 99% or more of the area. The conditions B-3, B-4 and other parameters described below are also the same.

In addition, in order to more easily exert the effects obtained based on conditions B-1 and B-2, The following conditions B-3 and B-4 are preferably satisfied.

Condition B-3: C _0.125 is 30.0% or more.

Condition B-4: C _2.0 is 40.0% or more.

Regarding condition B-3, C _0.125 is more preferably 35.0% or more, and further preferably 40.0% or more. In addition, in order to improve the anti-glare property, adhesion prevention property, interference fringe prevention property, and other properties imparted by the uneven shape, C _{0.125 is} preferably 50.0% or less.

Regarding condition B-4, C _2.0 is more preferably 50.0% or more, and further preferably 55.0% or more. In addition, in order to improve the anti-glare properties, adhesion prevention properties, interference fringe prevention properties, and other properties imparted by the uneven shape, C _{2.0 is} preferably 70.0% or less.

Furthermore, in the present invention, SRa expands the arithmetic average roughness Ra of the two-dimensional roughness parameter described in JIS B0601: 1994 to three dimensions, when orthogonal coordinate axes X and Y are set on the reference plane, the roughness curved surface is set It is Z(x, y), and when the size of the reference plane is Lx, Ly, it is calculated by the following formula (a).

(In the formula, A=Lx×Ly)

Moreover, if the height of the _i-th position in the X-axis direction and the j-th point in the Y-axis direction is Z _i,j , the arithmetic average roughness Sa can be calculated according to the following formula (b).

In addition, the reference plane when calculating SRa in each region is not obtained for each region, but is set as the reference plane obtained for the entire measurement range.

In the measurement of conditions A-1 and A-2, set a total of more than 100 measurement areas. In addition, each measurement area is set to be continuous and not spaced apart. In addition, each measurement area is preferably continuous in two directions of the X direction and the Y direction orthogonal thereto. For example, when the total number of measurement areas is set to 100, it is preferable to form 100 measurement areas from an area of 640 μm square, rather than form 100 measurement areas from an area of 64 μm×6400 μm.

Regarding the three-dimensional roughness curved surface, in terms of simplicity, it is preferable to use an interference microscope for measurement. Examples of such interference microscopes include the "New View" series manufactured by SEG Corporation. In addition, SRa can be calculated by the measurement and 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 can improve the glare prevention under the above conditions. Therefore, it is not necessary to increase the internal haze to more than necessary, and the resolution of the ultra-high-definition display element can be prevented from decreasing.

The total light transmittance of the optical sheet in JIS K7361-1:1997 is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more.

The haze of JIS K7136:2000 of the optical sheet is preferably 25 to 60%, more preferably 30 to 60%, and further preferably 30 to 50%. By setting the haze to 25% or more, anti-glare properties can be imparted, and the shape or damage of the electrode is not obvious. In addition, by setting the haze to 60% or less, it is possible to prevent the resolution of the ultra-high-definition display element from decreasing, and it is possible to easily prevent the contrast from decreasing.

In addition, when the haze is divided into a surface haze (Hs) and an internal haze (Hi), the surface haze is preferably 5 to 25%, more preferably 5 to 20%, and further preferably 7 to 15%. By setting the surface haze to 5% or more, the anti-glare property can be improved, and the shape or damage of the electrode can be made inconspicuous. By setting it to 25% or less, it is easy to prevent the decrease in contrast or the resolution. reduce.

In addition, the internal haze is preferably 15 to 40%, more preferably 20 to 40%, and further preferably 25 to 38%. By setting the internal haze to 15% or more, it is possible to easily prevent glare by synergy with the surface unevenness, and by setting it to 40% or less, it is possible to prevent the resolution of ultra-high-definition display elements from decreasing.

Also, regarding the ratio of the surface haze to the internal haze (Hs/Hi), from the viewpoint of the balance of the effects of the surface haze and the internal haze, it is preferably 0.1 to 0.5, and more preferably 0.2 to 0.4 .

The surface haze and internal haze can be obtained by, for example, the method described in the examples.

The optical sheet may be used without particular limitation as long as it has a concave-convex shape on at least one surface and satisfies the conditions A-1 and A-2, or satisfies the conditions B-1 and B-2. Also, the optical sheet may have a concave-convex shape on both sides, but from the viewpoint of operability, image visibility (resolution, whitening), it is preferable to have a concave-convex shape on one side, and the other side is substantially smooth (Ra0. 02μm or less).

In addition, the optical sheet may be a single layer of an uneven layer or a multilayer having an uneven layer on a transparent substrate. From the standpoint of operability and ease of manufacturing, a structure having an uneven layer on a transparent substrate is more suitable.

Examples of the method for forming the unevenness include: 1) a method using an embossing roller; 2) etching treatment; 3) molding using a mold; 4) formation of a coating film by coating. Among these methods, from the viewpoint of the reproducibility of the concave-convex shape, 3) the molding by the mold is more suitable, and from the viewpoint of productivity and handling of multiple varieties, 4) the coating by coating The film formation is more suitable.

The molding by the mold can be manufactured by a method of making a mold composed of a shape complementary to the concave-convex surface, pouring a material such as a polymer resin or glass into the concave-convex layer into the mold and hardening it, and then taking it out of the mold. When using a transparent substrate, you can After the polymer resin and the like are poured into the mold, the transparent base material is superimposed thereon, and then the polymer resin and the like are hardened and taken out together with the transparent base material from the mold and manufactured.

The formation of a coating film by coating can be formed by a method in which a coating liquid for forming a concave-convex layer containing a binder resin and particles is applied to a known coating method such as gravure coating or bar coating. On a transparent substrate, dry and harden as needed.

In order to satisfy the conditions A-1 and A-2, or satisfy the conditions B-1 and B-2, it is preferable that the coating liquid for forming the uneven layer contains organic particles and inorganic fine particles as particles. It is considered that by including different kinds of particles in the uneven layer in this way, the unevenness of the surface shape of the uneven layer can be reduced.

3 is a scanning transmission electron micrograph (STEM) showing the cross-section of the concavo-convex layer of the optical sheet of Example 1. The concavo-convex layer is formed by coating a concavo-convex layer containing a binder resin, organic particles, and inorganic fine particles The cloth is formed.

Generally, the surface of the concavo-convex layer where no organic particles are present is substantially smooth, but the position of the concavo-convex layer of FIG. 3 where there are no organic particles also has a gentle slope. It is considered that the reason is that the inorganic fine particles, the thixotropy of the coating liquid, and the drying characteristics of the solvent are affected, and there is no leveling as usual. It is believed that in this way, a gentle slope is formed even where no organic particles are present, so that the unevenness of the surface shape of the concavo-convex layer becomes less, and the conditions A-1 and A-2 can be satisfied, or the conditions B-1 and B-2 can be satisfied .

Organic particles include spherical, disc-shaped, rugby-shaped, and irregular shapes, and also include hollow particles, porous particles, and solid particles in these shapes. Among these, spherical solid particles are more suitable from the viewpoint of preventing glare.

-三聚氰胺-甲 醛縮合物、聚矽氧樹脂、氟系樹脂及聚酯等構成之粒子。 Examples of the organic particles include polymethyl methacrylate, acrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, and benzoguanidine.

-Particles composed of melamine-formaldehyde condensate, polysiloxane resin, fluorine resin and polyester.

The organic particles are preferably non-hydrophilized organic particles whose surface has not been hydrophilized. The reason for this is that, because silicon dioxide microparticles, which are representative examples of inorganic microparticles, have a high degree of hydrophilicity, organic particles are treated with non-hydrophilization, whereby organic particles and silicon dioxide are not dense in the uneven layer (for example, Silicon dioxide is not concentrated around the organic particles) and is evenly dispersed, thereby easily reducing the unevenness of the surface shape of the uneven layer.

In addition, among the above organic particles, acrylic-styrene copolymer particles and polystyrene particles are preferred, and polystyrene particles are more preferred. It is considered that the acrylic-styrene copolymer particles and polystyrene particles are difficult to precipitate in the uneven layer due to the small specific gravity, so the unevenness of the surface shape of the uneven layer becomes less. In addition, it is considered that the polystyrene particles have a high degree of hydrophobicity, so that they are not densely and uniformly dispersed in the concavo-convex layer with silicon dioxide fine particles, which are typical examples of inorganic fine particles, so that the unevenness of the surface shape of the concavo-convex layer becomes less . In addition, since the acrylic-styrene copolymer particles are easy to control the refractive index and the degree of hydrophilicity and hydrophobicity, they are good in terms of internal haze and easy control of aggregation/dispersion.

In addition, from the viewpoint of reducing the unevenness of the surface shape of the uneven layer, it is preferable that [the specific gravity of the organic particles/the specific gravity of the mixture of the binder resin and the inorganic fine particles] be less than 1.0.

Regarding the organic particles, from the viewpoint of reducing the unevenness of the surface shape of the uneven layer, the average particle diameter is preferably 2 to 10 μm, and more preferably 3 to 8 μm.

In addition, regarding the ratio of the average particle diameter of the organic particles to the thickness of the concavo-convex layer (the average particle diameter of the organic particles/thickness of the concavo-convex layer), from the viewpoint of reducing the unevenness of the surface shape of the concavo-convex layer, it is preferably 0.4 to 0.8, more preferably 0.5~0.7.

The average particle diameter of the organic particles can be calculated by the following operations (1) to (3).

(1) Use an optical microscope to shoot the transmission observation image of the optical sheet of the present invention. The magnification is preferably 500 to 2000 times.

(2) Select any 10 particles from the observation image, measure the long and short diameters of each particle, and calculate the particle size of each particle based on the average of the long and short diameters. The long diameter is set to the longest diameter of each particle on the screen. In addition, the short diameter line draws a line segment orthogonal to the midpoint of the line segment constituting the long diameter, and refers to the distance between the two points where the orthogonal line segment intersects with the particle.

(3) Perform the same operation 5 times on the observation image of another screen of the same sample, and set the value obtained from the number average of about 50 particle diameters as the average particle diameter of the organic particles.

Regarding the average primary particle diameter of inorganic fine particles and the average particle diameter of aggregates of inorganic fine particles, first, a cross section of the optical sheet of the present invention is photographed by TEM or STEM. After shooting, 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). Preferably, the acceleration voltage of TEM or STEM is set to 10kv~30kV, and the magnification is set to 50,000~300,000 times.

Regarding the content of the organic particles, from the viewpoint of reducing the unevenness of the surface shape of the uneven layer, it is preferably 2 to 25% by mass, more preferably 5 to 20% by mass of all the solid components forming the uneven layer, and It is preferably 6 to 12% by mass.

Examples of the inorganic fine particles include fine particles composed of silica, alumina, zirconia, and titania. By uniformly distributing the inorganic fine particles in the uneven layer, the unevenness of the surface shape of the uneven layer can be easily reduced. In addition, the inorganic fine particles preferably form aggregates in the uneven layer, and the aggregates are sparsely distributed. The formation of agglomerates by inorganic fine particles is more effective in reducing the unevenness of the surface shape. The sparse distribution of the agglomerates can reduce the influence of the diffusion of inorganic fine particles.

Among the above-mentioned inorganic fine particles, silicon dioxide fine particles are more suitable from the viewpoint of transparency and further reducing the unevenness of the surface shape of the uneven layer.

The so-called "uniformly distributed in the uneven layer" means: using a transmission electron microscope such as TEM, STEM, etc., at a magnification of 10,000 times, from the position where no organic particles in the thickness direction of the uneven layer can be observed to observe any cross section At 10 locations, when measuring the area ratio of silica particles in the observation area of 5 μm square in each section, set the average value to M and the standard deviation to S. At this time, S/M ≦0.1.

The so-called "sparsely distributed agglomerates in the concavo-convex layer" means that the inorganic fine particles are locally unevenly distributed, which means: when observed in the same manner as above, the dioxide in the observation area measuring 0.5 μm square in each section When the area ratio of silicon particles is M, the average value is M and the standard deviation is S. At this time, S/M≧0.2.

In addition, the distribution of such inorganic fine particles can be easily determined by cross-sectional electron microscope observation in the thickness direction of the concavo-convex layer. For example, FIG. 3 is a cross-sectional STEM photograph of the optical sheet of Example 1. The light-colored area in the lower part is the substrate, and the dark band-shaped area in the upper part of the substrate is the profile of the uneven layer. In the cross section of the uneven layer, the black spots are observed as aggregates of inorganic fine particles (silica particles), and it can be clearly confirmed that the aggregates of silica fine particles are uniformly dispersed in the uneven layer. In addition, the area ratio of the aggregates of inorganic fine particles can be calculated using image analysis software, for example.

The inorganic fine particles are preferably surface-treated. By surface-treating the inorganic fine particles, the distribution of the inorganic fine particles in the uneven layer can be easily and appropriately controlled. In addition, the chemical resistance and saponification resistance of the inorganic fine particles can be improved.

In addition, in order to prevent the inorganic fine particles from being concentrated around the organic particles, it means that the inorganic fine particles The "Mn" of the area ratio of the area within the circumference of 500 nm away from the organic fine particles and the area other than the organic fine particles, and the inorganic area in the area outside the circumference of 500 nm away from the organic fine particles The "Mf" of the area ratio of the fine particles preferably satisfies the relationship of Mf/Mn≧1.0. Mn and Mf can be calculated by microscopically observing the cross section of the organic particles in the thickness direction of the concavo-convex layer with a transmission electron microscope such as TEM or STEM at a magnification of 10,000 times.

As the above-mentioned surface treatment, a hydrophobization treatment to make the surface of the inorganic fine particles hydrophobic is preferable. As the hydrophobizing treatment, for example, a method of treating inorganic fine particles with a silane compound having an alkyl group such as a methyl group, an octyl group, or the like can be cited.

For example, there are hydroxyl groups (silanol groups) on the surface of the silica particles, but by performing the above-mentioned surface treatment, the hydroxyl groups on the surfaces of the silica particles can be reduced, the silica particles can be prevented from excessively agglomerating, and the dioxide can be suppressed The silicon particles are dispersed unevenly.

In the case of using silica fine particles as inorganic fine particles, in order to suppress excessive aggregation, it is preferably amorphous silica. On the other hand, when the silicon dioxide particles are crystalline silicon dioxide, there is a lattice defect contained in the crystal structure, which causes the Lewis acidity of the silicon dioxide particles to become strong, resulting in excessive silicon dioxide particles. The situation of agglomeration.

As the silica fine particles are easily aggregated and easily form aggregates in the particle size range described later, for example, fumed silica can be preferably used.

The so-called smoked silicon dioxide refers to an amorphous silicon dioxide having a particle diameter of 200 nm or less produced by a dry method, and obtained by subjecting a volatile compound containing silicon to a gas-phase reaction. The smoked silicon dioxide can be produced by, for example, hydrolyzing silicon compounds such as SiCl ₄ in a flame of oxygen and hydrogen, and examples include AEROSIL R805 (manufactured by Aerosil Corporation of Japan).

The content of the inorganic fine particles is not particularly limited, but it is preferably 1.0 to 15.0% by mass of the total solid content forming the uneven layer, more preferably 2.0 to 10.0% by mass, and still more preferably 3.0 to 8.0% by mass. By setting it as this range, the unevenness of the surface shape of the uneven layer can be easily reduced by controlling the leveling property and suppressing the polymerization shrinkage of the uneven layer.

Also, regarding the ratio of the content of organic particles and inorganic fine particles in the uneven layer (the content of organic particles/the content of inorganic fine particles), from the viewpoint of easily reducing the unevenness of the surface shape of the uneven layer, it is preferably 0.5 to 2.5 , More preferably 0.8~2.2.

The average primary particle diameter of the inorganic fine particles is preferably 1-100 nm. By setting the average primary particle size to 1 nm or more, it is easy to form an appropriate aggregate. By setting it to 100 nm or less, it is possible to suppress a decrease in contrast due to light diffusion and an excessive increase in internal haze. The more preferable lower limit is 5 nm, the more preferable upper limit is 50 nm, and the more preferable upper limit is 20 nm.

The aggregates of silicon dioxide fine particles are preferably formed in a structure connected in any direction as shown in the cross-sectional electron micrograph of FIG. 3. By forming agglomerates of silicon dioxide microparticles connected in any direction in the concavo-convex layer, uniform concave-convex shapes based on organic particles can be easily formed.

In addition, the structure in which silicon dioxide microparticles are connected in any direction includes, for example, a structure in which silicon dioxide microparticles are continuously connected linearly (straight chain structure), and a structure in which multiple straight chain structures are wound Any structure such as a structure, a branch structure having one or more side chains in which a plurality of silica fine particles are continuously formed in the linear structure, or the like.

In order to form agglomerates in which silicon dioxide particles are connected in any direction as described above, smoked silicon dioxide is preferably used.

The average particle diameter of the aggregate of inorganic fine particles is preferably 100 nm to 1 μm. borrow By setting the average particle diameter of the aggregate to 100 nm or more, the unevenness of the surface shape of the uneven layer can be easily reduced, and by setting it to 1 μm or less, the decrease in contrast due to light diffusion can be suppressed. The lower limit of the average particle size of the aggregate is 200 nm, and the upper limit is 800 nm.

The binder resin of the concavo-convex layer preferably contains a thermosetting resin composition or a free radiation-curable resin composition, and from the viewpoint of improving mechanical strength, it preferably contains a free radiation-curable resin composition, wherein, Furthermore, it preferably contains an ultraviolet curable resin composition.

The thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition that is hardened by heating.

Examples of thermosetting resins include acrylic resins, urethane resins, phenol resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and polysiloxane resins. Regarding the thermosetting resin composition, a hardener may be added to these curable resins if necessary.

The free radiation curable resin composition is a composition containing a compound having a free radiation curable functional group (hereinafter, also referred to as "free radiation curable compound"). Examples of free radiation-curable functional groups include ethylenically unsaturated bonding groups such as (meth)acryloyl, vinyl, and allyl groups, and epoxy groups and oxetanyl groups. The free radiation-curable compound is preferably a compound having an ethylenically unsaturated bonding group, more preferably a compound having two or more ethylenically unsaturated bonding groups, and among them, more preferably having more than two Multifunctional (meth)acrylate compound with an ethylenically unsaturated bonding group. As the multifunctional (meth)acrylate-based compound, any of monomers and oligomers can be used.

In addition, in this specification, "(meth)acrylate" means methacrylate and acrylate.

In addition, in this specification, the term "free radiation" means that the electromagnetic wave or the charged particle beam has energy quanta that can polymerize or crosslink the molecules. Usually, ultraviolet (UV) or electron beam (EB) can be used. In addition, Electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion beams can also be used.

The free radiation-curable resin composition preferably contains 50% by mass or more of a polyfunctional (meth)acrylate compound containing no hydroxyl group in the molecule, and more preferably contains 60% by mass or more.

By increasing the ratio of polyfunctional (meth)acrylate compounds that do not contain hydroxyl groups in the molecule, it is easy to use a highly polar solvent (such as isopropyl alcohol) as the solvent for the coating liquid for forming the uneven layer Evaporating this solvent can suppress excessive aggregation of inorganic fine particles.

Examples of the multifunctional (meth)acrylate-based compound that does not contain a hydroxyl group in the molecule include neopentaerythritol tetraacrylate (PETTA), 1,6-hexanediol diacrylate (HDDA), and dipropylene glycol. Diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), PO modified neopentyl glycol diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate (TMPTA), tri Methylolpropane ethoxy triacrylate, dipentaerythritol hexaacrylate (DPHA), neopentyl alcohol ethoxytetraacrylate, di-trimethylolpropane tetraacrylate, etc. Among them, neopentaerythritol tetraacrylate (PETTA) can be preferably used.

Examples of other free radiation-curable compounds include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Bond compound, trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl tetraol (meth)acrylate , Dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(methyl) ) Acrylate, di-trimethylolpropane Tetra (meth) acrylate, neopentaerythritol tetra (meth) acrylate, di neopentaerythritol penta (meth) acrylate, tri neopentaerythritol octa (meth) acrylate, tetra neopentaerythritol Alcohol deca(meth)acrylate, isocyanurate tri(meth)acrylate, isocyanurate di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate Group) acrylate, bisphenol di(meth)acrylate, diglycerol tetra(meth)acrylate, adamantyl di(meth)acrylate, isobornyl di(meth)acrylate, Compounds having two or more unsaturated bonds, such as dicyclopentane di(meth)acrylate and tricyclodecane di(meth)acrylate.

In addition, in the present invention, as the free radiation-curable compound, those modified with PO, EO, or the like can also be used.

Furthermore, as the free radiation-curable compound, a relatively low molecular weight polyester resin having an unsaturated double bond, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal can be used Resin, polybutadiene resin, polythiol polyene resin, etc.

When the free radiation-curable compound is an ultraviolet-curable compound, the free radiation-curable composition preferably contains additives such as a photopolymerization initiator or a photopolymerization accelerator.

等之1種以上。 Examples of the photopolymerization initiator include acetophenone, benzophenone, α-hydroxyalkylphenone (α-hydroxyalkylphenone), Michler's ketone, benzoin, acetophenone methyl ketal, Benzoyl benzoate, α-acyl oxime ester, 9-oxythio

More than one kind.

The melting point of these photopolymerization initiators is preferably 100°C or higher. By setting the melting point of the photopolymerization initiator to 100° C. or higher, the photopolymerization initiator remaining due to heat during the formation of the transparent conductive film of the touch panel or the crystallization step can be sublimated, thereby preventing the transparent conductive film The reduction in resistance is impaired.

In addition, the photopolymerization accelerator can reduce the polymerization inhibition caused by the air during curing, and accelerate the curing rate. For example, it can be selected from isoamyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, etc. One or more.

The thickness of the concavo-convex layer is preferably from 2 to 10 μm, and more preferably from 5 to 8 μm from the viewpoint of curl suppression, mechanical strength, hardness, and toughness balance.

The thickness of the concavo-convex layer is, for example, an image of a cross-section taken by scanning transmission electron microscopy (STEM), the thickness of 20 locations is measured, and the average value of the 20 locations is calculated. Preferably, the acceleration voltage of STEM is set to 10 kV to 30 kV, and the magnification is set to 1000 to 7000 times.

烷、四氫呋喃等)、脂肪族烴類(己烷等)、脂環式烴類(環己烷等)、芳香族烴類(甲苯、二甲苯等)、鹵化烴類(二氯甲烷、二氯乙烷等)、酯類(乙酸甲酯、乙酸乙酯、乙酸丁酯、丙二醇單甲醚乙酸酯等)、醇類(丁醇、環己醇等)、賽珞蘇類(甲基賽珞蘇、乙基賽珞蘇等)、乙酸賽珞蘇類、亞碸類(二甲基亞碸等)、醯胺類(二甲基甲醯胺、二甲基乙醯胺等)等，亦可為該等之混合物。 In the coating liquid for forming the uneven layer, a solvent is generally used in order to be able to adjust the viscosity and dissolve or disperse the components. The surface state of the uneven layer after coating and drying varies according to the type of solvent, so it is preferable to select the solvent considering the saturated vapor pressure of the solvent, the permeability of the solvent to the transparent substrate, and so on. Specifically, the solvent can be exemplified by ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), and ethers (two

Alkane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated hydrocarbons (dichloromethane, dichloromethane, etc.) Ethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, etc.), alcohols (butanol, cyclohexanol, etc.), celluloids (methylcellulose (Luosu, ethylcellulose, etc.), ethylcellulose acetate, sulfonate (dimethyl sulfonate, etc.), amides (dimethylformamide, dimethylacetamide, etc.), etc., It can also be a mixture of these.

When the drying of the solvent is slow, the inorganic fine particles aggregate excessively in the uneven layer, and it becomes difficult to reduce the unevenness of the surface shape of the uneven layer. In order to prevent the excessive aggregation of the inorganic fine particles, the solvent preferably contains a specific amount of those with high polarity and fast evaporation rate.

In addition, the solvent with high polarity and fast volatilization rate evaporates before other solvents. Therefore, the hydrophobicity around the organic fine particles becomes stronger when the coating film is formed. Therefore, by using a solvent with a high polarity and a fast volatilization rate, the inorganic fine particles can be prevented from being concentrated around the organic particles, and the organic particles and the inorganic fine particles can be uniformly dispersed in the uneven layer without being dense.

In this specification, the so-called "high-polarity solvent" means a solvent with a solubility parameter of 10 [(cal/cm ³ ) ^1/2 ] or more, and the so-called "solvent with a fast evaporation rate" means a solvent with a relative evaporation rate of 150 or more Solvent.

The solubility parameter can be calculated by the method of Fedors. The method of Fedors is described in, for example, "SP Value Basics, Application and Calculation Method" (published by Hideki Yamamoto Information Agency Co., Ltd., 2005). In the method of Fedors, the solubility parameter is calculated according to the following formula.

Solubility parameter = [Σ E _coh /Σ V] ²

In the above formula, E _coh is the agglutination energy density, and V is the molar molecular volume. Based E _coh and V is determined by each of the radicals was determined as the sum of E _coh and V [Sigma sum Σ E _coh and V, whereby the solubility parameter can be calculated.

In this specification, the "relative evaporation rate" refers to the relative evaporation rate when the evaporation rate of n-butyl acetate is set to 100, and under the evaporation rate measured according to ASTM D3539-87, according to the following formula Figure it out. Specifically, the evaporation time of n-butyl acetate and the evaporation time of each solvent at 25°C under dry air are measured and calculated.

Relative evaporation rate = [(time required for 90% by weight of n-butyl acetate to evaporate)/(time required for 90% by weight of solvent to evaporate)] × 100

Examples of the solvent with high polarity and fast volatilization rate include ethanol and isopropanol, among which isopropanol is suitable.

In addition, the content of the solvent with high polarity and fast evaporation rate is preferably 10 to 40% by mass of all solvents. By setting it to 10% by mass or more, the excessive aggregation of the inorganic fine particles can be easily suppressed, and by setting it to 40% by mass or less, it can be suppressed that the leveling property of the coating liquid for forming the concavo-convex layer is insufficient due to excessive volatilization of the solvent .

In addition, from the viewpoint of easily obtaining the above-mentioned uneven shape, it is preferable to control the drying conditions when forming the uneven 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 air speed is preferably 0.2 to 50 m/s. In addition, in order to control the leveling of the concavo-convex layer by drying conditions, the irradiation of free radiation is preferably performed after drying.

In addition, from the viewpoint of making the surface unevenness moderately smooth and easily obtaining the above-mentioned unevenness shape, it is preferable that the unevenness layer forming coating liquid contains a leveling agent. The leveling agent may include a fluorine-based or polysilicone-based leveling agent, and preferably a fluorine-based leveling agent that can easily suppress the Benard cell structure in the uneven layer. The amount of the leveling agent added is preferably 0.01 to 0.5% by weight, and more preferably 0.05 to 0.2% by weight relative to the total solid content of the coating liquid for forming the uneven layer.

In addition, the coating liquid for forming the uneven layer is preferably prepared by (1) after the step of mixing the binder resin and the organic particles into a solvent and stirring to prepare an intermediate composition, (2) mixing the inorganic fine particles To the intermediate composition and disperse it.

By adjusting the coating liquid for forming the uneven layer as described above, unevenness of the surface shape of the uneven layer can be easily suppressed. On the other hand, in a situation different from the above-mentioned adjustment method (in the case where inorganic fine particles are added to the solvent before adding the organic particles or binder resin), excessive aggregation of the inorganic fine particles occurs due to the attack of the solvent, making it difficult to reduce the unevenness The surface shape of the layer is uneven.

In order to make the above effect more certain, when adding inorganic fine particles in step (2), the inorganic fine particles The particles are preferably inorganic fine particle dispersions dispersed in a solvent.

As the transparent base material of the optical sheet, it is preferable to have light transmittance, smoothness, heat resistance, and excellent mechanical strength. Examples of such a transparent base material include polyester, triethyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamidoamine, polyimide, polyether sulfone, polysulfone, and polypropylene , Polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane and amorphous olefin (Cyclo-Olefin-Polymer, COP) and other plastic films. The transparent substrate can also be formed by laminating more than 2 plastic films.

Among the above, from the viewpoint of mechanical strength or dimensional stability, it is preferably stretch-processed, particularly preferably biaxially stretched polyester (polyethylene terephthalate, polyethylene naphthalate) (polyethylene naphthalate)).

From the viewpoint of translucent optical isotropy, TAC and acrylic are more suitable. In addition, TAC and acrylic acid are easily dissolved by a solvent, and the dissolved TAC component and acrylic component flow into the uneven layer and have the effect of pushing up organic particles with a small specific gravity. That is, it is considered that by using TAC and acrylic as a transparent substrate, it is difficult for the organic particles to sink in the uneven layer, and it is easy to reduce the unevenness of the surface shape of the uneven layer.

In terms of excellent weather resistance, COP and polyester are more suitable. In addition, in the case of observing the image of the liquid crystal display through polarized sunglasses, in order to prevent the unevenness of different colors from being observed on the display screen, the plastic film with a blocking value of 3000~30000nm or 1/4 wavelength phase difference The plastic film is more suitable.

The thickness of the transparent substrate is preferably 5 to 300 μm, more preferably 30 to 200 μm.

In order to improve adhesion, in addition to corona discharge treatment, oxidation treatment and other physical treatments on the surface of the transparent substrate, it can also be pre-coated with an anchoring agent or primer (primer) paint.

The optical sheet may have functional layers such as an anti-reflection layer, an anti-fouling layer, and an antistatic layer on the uneven surface and/or on the surface opposite to the uneven surface. In addition, when the structure of the uneven layer is provided on the transparent base material, in addition to the above-mentioned positions, a functional layer may be provided between the transparent base material and the uneven layer.

The touch panel of the present invention can impart various characteristics such as anti-glare properties and can make the anti-glare properties better. In particular, the optical sheet is used as a surface member of a touch panel, and is arranged such that the surface of the concave-convex shape side of the optical sheet becomes the surface, whereby the reduction in contrast can be suppressed and anti-glare properties can be easily imparted. More suitable.

[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 with a pixel density of 300 ppi or more. The optical sheet has a concave-convex shape on the surface, and the optical sheet satisfies the above conditions A-1 and A-2, or Satisfy the above conditions B-1 and B-2.

An ultra-high-definition display element with a pixel density of 300 ppi or more is prone to glare as described above, but in the present invention, by using a specific optical sheet as an optical sheet having a concave-convex shape, various characteristics such as anti-glare properties can be imparted and glare can be prevented .

As the optical sheet used in the display device of the present invention, the same optical sheet used in the touch panel of the present invention described above can be used.

Examples of display elements include liquid crystal display elements, liquid crystal display elements for in-cell touch panels, EL display elements, and plasma display elements.

The liquid crystal element embedded in the touch panel incorporates the functions of a touch panel such as a resistive film type, an electrostatic capacitance type, and an optical type in the liquid crystal element formed by sandwiching liquid crystal between two glass substrates. Furthermore, make The display method of the liquid crystal of the liquid crystal element in which the touch panel is embedded includes: IPS method, VA method, multi-field method, OCB method, STN method, TSTN method, etc. The liquid crystal element in which the touch panel is embedded is described in Japanese Patent Laid-Open No. 2011-76602 and Japanese Patent Laid-Open No. 2011-222009, for example.

The optical sheet can be disposed on the front of the display element in the following order, for example.

(a) Display element/surface protection plate/optical sheet

(b) Display element/optical sheet

(c) Display element/touch panel with optical sheet as constituent member

(d) Display element/optical sheet/surface protection plate

In the case of (a) and (b), the anti-glare property can be imparted by preventing the uneven surface of the optical sheet toward the surface (with the uneven surface facing the side opposite to the display element) Glare, in turn, can make damage to the surface or display elements less noticeable.

In the case of (c), by arranging the optical sheet as in the above-described embodiment of the touch panel of the present invention, various characteristics such as anti-glare properties can be imparted, and glare can be prevented.

In addition, in the case of (b) and (d), if the concave-convex surface of the optical sheet is arranged to face the display element side with the air layer interposed, adhesion and interference fringes can be prevented and can be generated in the display element. The damage is not obvious.

In recent years, mobile information terminals represented by smart phones are mostly used outdoors. Therefore, in the display device of the present invention, it is preferable to arrange the optical sheet on the outermost surface of the display device and use the uneven surface toward the surface side (the side opposite to the display element).

[Optical sheet]

The optical sheet of the present invention has a concave-convex shape on the surface, and the optical sheet satisfies the above condition A -1 and A-2, or satisfy the above conditions B-1 and B-2, the optical sheet is used for the front of the display element with a pixel density of 300 ppi or more.

As the optical sheet of the present invention, the same as the optical sheet used in the above-mentioned touch panel of the present invention can be mentioned.

The optical sheet of the present invention can be applied to the front surface of a display element with a pixel density of 300 ppi or more to impart anti-glare properties and other characteristics, and to prevent the glare and resolution of image light from ultra-high-definition display elements. It’s better.

In recent years, mobile information terminals represented by smart phones are mostly used outdoors. Therefore, the optical sheet of the present invention is preferably used on the outermost surface of a touch panel or a display device, with the uneven surface facing the surface side (the side opposite to the display element).

[Screening method of optical sheet]

The screening method of the optical sheet of the present invention is a method of screening an optical sheet having a concave-convex shape on the surface, and screening those satisfying the above conditions A-1 and A-2, or satisfying the above conditions B-1 and B-2 as optical sheets, the Optical sheets are used on the front of display elements with pixel density above 300ppi.

In the screening method of the optical sheet of the present invention, even if the optical sheet is not assembled in the display device, the optical sheet with excellent glare prevention when used for ultra-high-definition display elements with a pixel density of 300 ppi or more can be screened, which can be highly efficient Quality management of optical sheets.

The judgment conditions for screening the optical sheet are the above conditions A-1 and A-2, or the above conditions B-1 and B-2 as necessary conditions. The determination conditions of the screening optical sheet preferably include the above conditions A-1 and A-2, and the above conditions B-1 and B-2 as required conditions.

The numerical range of each condition is preferably a suitable numerical range of the above-mentioned optical sheet. For example, the determination condition of the condition A-1 is preferably σ _SRa of 0.040 μm or less.

When the conditions B-1 and B-2 are included as the judgment conditions, from the viewpoint of screening the optical sheets capable of preventing glare more accurately, it is more preferable to use the following conditions B-3 and B-4 as the judgment conditions .

In addition, when conditions A-1 and A-2 are included as judgment conditions, and conditions B-1 and B-2 are included as judgment conditions, the optical sheets that can prevent glare are screened more accurately From the viewpoint of the above, it is more preferable to use the following condition C-1 as a judgment condition.

Furthermore, the numerical range of conditions B-3, B-4, and C-1 is preferably the appropriate numerical range of the above-mentioned optical sheet.

Condition B-3: C _0.125 is 30.0% or more.

Condition B-4: C _2.0 is 40.0% or more.

Condition C-1: The internal haze of the optical sheet is 15-40%.

[Manufacturing method of optical sheet]

The manufacturing method of the optical sheet of the present invention is a method of manufacturing an optical sheet having a concave-convex shape on the surface, manufactured in such a manner that the optical sheet satisfies the above conditions A-1 and A-2, or satisfies the above conditions B-1 and B-2 The optical sheet is used on the front surface of a display element with a pixel density of 300 ppi or more.

In the method for manufacturing an optical sheet of the present invention, an optical sheet capable of imparting various characteristics such as anti-glare properties and preventing glare of image light of an ultra-high-definition display element having a pixel density of 300 ppi or more can be efficiently manufactured.

The manufacturing method of the optical sheet of the present invention must control the manufacturing conditions in such a manner that the above conditions A-1 and A-2, or the above conditions B-1 and B-2 are satisfied. The manufacturing method of the optical sheet of the present invention preferably satisfies the above conditions A-1 and A-2, and the above conditions B-1 and B-2 Control the manufacturing conditions.

The numerical range of each condition is preferably a suitable numerical range of the above-mentioned optical sheet. For example, in condition A-1, σ _SRa is preferably 0.040 μm or less.

In the case where the manufacturing conditions are controlled by satisfying the above conditions B-1 and B-2, the manufacturing conditions are preferably controlled by satisfying the above conditions B-3 and B-4.

Furthermore, when the conditions A-1 and A-2 are included in the control of the manufacturing conditions, and the conditions B-1 and B-2 are included in the control of the manufacturing conditions, it is further preferable to satisfy the above condition C- 1 way to control manufacturing conditions.

Conditions A-1, A-2, B-1~B-4 can be controlled by reducing the unevenness of the surface shape of the uneven layer.

Regarding the specific means for controlling the conditions A-1, A-2, B-1 to B-4, when the concave-convex layer is formed using a mold, it is only necessary to control the shape of the mold. In addition, specific methods for controlling the conditions A-1, A-2, B-1 to B-4 when forming the uneven layer by coating include organic particles, inorganic fine particles, binder resin, The leveling agent, the solvent and the drying conditions are set as the above-mentioned suitable embodiment.

Condition C-1 can be controlled by internal diffusion elements. 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 size of the organic particles, the amount of the organic particles added, and the refractive index of the organic particles. In addition, the concentration of materials (inorganic fine particles) other than organic particles added to the binder resin also affects the internal diffusion elements.

Examples

Next, the present invention will be described in further detail by examples, but the present invention It is not limited by these examples. In addition, "parts" and "%" refer to quality standards unless otherwise specified.

1. Physical properties measurement and evaluation of optical sheets

As described below, the physical properties of the optical sheets of Examples and Comparative Examples were measured and evaluated. The results are shown in Table 1.

1-1. Concavo-convex shape of optical sheet

<SRa>

The surface of each optical sheet obtained in the examples and comparative examples on the opposite side to the surface on which the concavo-convex layer was formed was attached to a glass plate via a transparent adhesive to prepare a sample, using a white interference microscope (New View7300, SEG Manufactured by the company), and measure and analyze the surface shape of the optical sheet under the following conditions.

Furthermore, the measurement and analysis software uses the Microscope Application of MetroPro version 8.3.2.

(Measurement conditions)

Objective lens: 50 times

Zoom: 1 times

Measuring area: 1mm×1mm

Resolution (every 1 point interval): 0.44μm

(Analysis conditions)

Removed: None

Filter (Filter): Band Pass (BandPass)

Filter Type: Gaussian Spline

Low wavelength: 800μm

High wavelength: 3μm

Remove spikes (Remove spikes): on (on)

Spike Height (×RMS): 2.5

The low wavelength corresponds to the cut-off value λ c of the roughness parameter.

The measurement data is divided into 144 areas of 12×12 (one area is 64μm square), and the SRa of each area is displayed on the Surface Map screen. Calculate σ _SRa and SRa _AVE based on SRa of each area.

1-2. Transmission image clarity

Using the image clarity measuring instrument (trade name: ICM-1T) manufactured by Suga Test Instruments, in accordance with JIS K7374, five kinds of transmission images passing through optical combs having widths of 0.125mm, 0.25mm, 0.5mm, 1mm, and 2mm Clarity is measured.

1-3. Haze

First, using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute), the haze (overall haze) was measured in accordance with JIS K-7136:2000. In addition, on the surface of the optical sheet, a TAC film (manufactured by Fuji Film Company, TD80UL) with a thickness of 80 μm is attached via a transparent adhesive, thereby flattening the uneven shape to make it flat, thereby eliminating the effect of haze caused by the surface shape In this state, the haze measurement is performed to obtain the internal haze (Hi). Then, the internal haze value is subtracted from the overall haze value to obtain the surface haze (Hs). The light incident surface is set to the base material side.

1-4. Glare

In each of the optical sheets obtained in Examples and Comparative Examples, the surface of the optical sheet on which the concavo-convex layer was not formed and the glass surface of the matrix on which the black matrix (glass thickness 0.7 mm) was not formed were bonded with a transparent adhesive. For the sample thus obtained, a white surface light source (manufactured by Hakba Corporation, LIGHTBOX, average brightness 1000 cd/m ² ) was provided on the black matrix side, thereby causing glare simulation. Use the CCD camera (KP-M1, C mount adaptor, extension tube); PK-11A Nikon, camera lens; 50mm, F1.4s NIKKOR . Set the distance between the CCD camera and the optical sheet to 250mm, and adjust the focus of the CCD camera to the optical sheet. The image captured by the CCD camera is taken into a personal computer, and analyzed using image processing software (ImagePro Plus ver.6.2; manufactured by Media Cybernetics) in the following manner.

First, select an evaluation position of 200×160 pixels from the captured image, and convert to 16-bit grayscale at the evaluation position. Next, select a low-pass filter from the enhancement label of the filter command and apply the filter under the condition of "3 x 3, order 3, intensity 10". This removes the components from the black matrix pattern. Next, select flattening and perform shading correction under the condition of "background: dark, target width 10". Then, under the contrast enhancement command, contrast enhancement is performed in the form of "contrast: 96, brightness: 48". The obtained image is converted into 8-bit grayscale, and for 150×110 pixels among them, the deviation of the value of each pixel is calculated as the standard deviation value, thereby digitizing the glare. It is considered that the smaller the numerical glare value, the less glare. In addition, the evaluation was performed with the black matrix corresponding to a pixel density of 350 ppi and the pixel density of 200 ppi.

1-5. Anti-glare

Place the black acrylic plate on the substrate side of the obtained optical sheet through a transparent adhesive and place the evaluation sample on a horizontal surface. Dispose the fluorescent lamp above the distance of 1.5m from the sample for evaluation. Move to the sample for evaluation, and under the environment where the illuminance on the sample for evaluation is set to 800 to 1200 Lx, perform visual functional evaluation from various angles and evaluate according to the following criteria.

A: The image of the fluorescent lamp cannot be recognized from any angle.

B: The image of the fluorescent lamp is reflected, but the outline of the fluorescent lamp is blurred, and the boundary part of the outline cannot be recognized.

C: The image of the fluorescent lamp is reflected like a mirror, which can clearly identify the outline of the fluorescent lamp (the boundary of the outline).

1-6. Albino

A sample obtained by bonding the transparent substrate side surface of the optical sheet and the black acrylic plate through a transparent adhesive was prepared. Regarding the produced samples, in a dark room, under a table stand using a three-wavelength fluorescent tube as a light source, observe the white turbidity according to the following criteria.

A: White is not observed.

C: White is observed.

1-7. Interference fringes

Two optical sheets are overlapped so that the concave-convex surface side of one optical sheet faces the transparent substrate side of the other optical sheet. As a result, the person who does not generate interference fringes is set to "A", and the person who produces interference fringes is set to "C".

2. Preparation of coating solution for forming uneven layer

2-1. Coating liquid for forming uneven layer 1

The intermediate composition was obtained by dispersing the blending components shown below with a bead mill. Next, the blending components shown below are dispersed by a bead mill to obtain a dispersion of inorganic fine particles. Furthermore, while the intermediate composition was stirred by the disperser, the inorganic fine particle dispersion was slowly added to obtain the uneven layer forming coating liquid 1.

(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 Chemical Co., Ltd.)/11 parts by mass

‧Pentaerythritol tetraacrylate (specific gravity 1.165)/60 parts by mass

‧Aminoester acrylate (trade name "V-4000BA", manufactured by Dickson) / 40 parts by mass

‧Photopolymerization initiator (trade name "Irgacure 184", manufactured by BASF JAPAN)/5 parts by mass

‧Polyether modified polysilicone (trade name "TSF 4460", made by Momandifu Performance Materials) / 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)

‧Fumigated silica (octyl silane treatment; average primary particle size 12nm, specific gravity 2.00, made by Japan Aerosil)/7 parts by mass

‧Toluene/55 parts by mass

‧Isopropyl alcohol/20 parts by mass

2-2. Coating liquid for forming uneven layer 2

Except having set the blending amount of the organic particles in the intermediate composition to 14 parts by mass, the concavo-convex layer forming coating liquid 2 was obtained in the same manner as the concavo-convex layer forming coating liquid 1.

2-3. Coating solution for forming uneven layer 3

The blending amount of the organic particles in the intermediate composition is set to 8 parts by mass, and further the blending amount of the smoked silica in the inorganic fine particle dispersion is set to 9 parts by mass, in addition to forming the coating liquid with the uneven layer 1 The coating liquid for forming the uneven layer 3 is obtained in the same manner.

2-4. Coating solution for forming uneven layer 4

The organic particles of the intermediate composition were 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.) and the blending amount was set to 12 mass In addition, except for this, the uneven layer forming coating liquid 4 is obtained in the same manner as the uneven layer forming coating liquid 1.

2-5. Coating solution for forming uneven layer 5

The composition 5 for the uneven layer was obtained by dispersing the blending components shown below with a bead mill.

‧Organic particles (non-hydrophilized polystyrene particles, average particle diameter 3.5 μm, refractive index 1.59, specific gravity 1.06, manufactured by Zheyan Chemical Company/14 parts by mass)

‧Pentaerythritol triacrylate/100 parts by mass

‧Acrylic polymer (molecular weight 75,000, manufactured by Mitsubishi Rayon)/10 parts by mass

‧Photopolymerization initiator (trade name "Irgacure 184", manufactured by BASF Japan)/5 parts by mass

‧Polyether modified polysilicone (trade name "TSF 4460", made by Momandifu Performance Materials) / 0.025 parts by mass

‧Toluene/120 parts by mass

‧Cyclohexanone/30 parts by mass

2-6. Concavo-convex layer forming coating liquid 6

The organic particles were 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.), and other than the composition for uneven layer 5 The composition 6 for the uneven layer was obtained in the same manner.

2-7. Coating solution for forming uneven layer 7

It is obtained in the same manner as the composition 5 for concave-convex layers except that organic particles are not blended Composition 7 for uneven layer.

3. Production of optical sheets

[Example 1]

On a transparent substrate (triacetyl cellulose resin film with a thickness of 80 μm, manufactured by Fuji Photo Film Co., Ltd., TD80UL), apply the uneven layer to form the coating liquid 1, and dry for 30 seconds at 70°C and a wind speed of 5 m/s. After that, ultraviolet rays were irradiated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the cumulative light amount became 100 mJ/cm ^{2 to} form an uneven layer, thereby obtaining an optical sheet. The film thickness of the uneven layer is 6.0 μm.

[Examples 2 to 4]

The optical sheets of Examples 2 to 4 were obtained in the same manner as in Example 1, except that the coating liquid for forming the uneven layer 1 was set to the coating liquid for uneven layers 2 to 4.

[Comparative Example 1]

The optical sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the coating liquid for forming the uneven layer 1 was set as the coating liquid for uneven layer 5 and the film thickness of the uneven layer was 4.5 μm.

[Comparative Example 2]

The optical sheet of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the coating solution 5 for forming a concavo-convex layer was used as the coating solution 6 for concavo-convex 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 solution 5 for forming a concavo-convex layer was used as the coating solution 7 for concavo-convex layer.

It is clear from the results in Table 1 that the optical sheets of Examples 1 to 4 can impart various characteristics such as anti-glare properties, and can prevent glare of ultra-high-definition display elements having a pixel density of 300 ppi or more, and also have excellent contrast. In addition, regarding the optical sheets of Examples 1 to 4, the glare prevention performance of the display element with a pixel density of 350 ppi is extremely good compared to the optical sheets of Comparative Examples 1 to 2, but for the display element with a pixel density of 200 ppi The gap between the glare prevention performance and the effect of the optical sheets of Comparative Examples 1 and 2 becomes smaller. It can be seen that the optical sheets of Examples 1 to 4 are extremely useful for ultra-high-definition display elements with a pixel density of 300 ppi or more.

In addition, the optical sheet of Comparative Example 3 does not contain light-transmitting particles in the concavo-convex layer, and therefore is excellent in glare prevention, but has poor anti-glare properties, generates interference fringes and is not durable.

4. Production of touch panel

On the transparent substrate sides of the optical sheets of Examples 1 to 4 and Comparative Examples 1 to 3, a conductive film of indium tin oxide with a thickness of 20 nm was formed by a sputtering method to be an upper electrode plate. Next, a conductive film of indium tin oxide with a thickness of about 20 nm was formed on one surface of a tempered glass plate with a thickness of 1 mm by a sputtering method to form a lower electrode plate. Next, on the surface of the lower electrode plate with the conductive film, the free radiation-curable resin (Dot Cure TR5903, Sun Ink Co., Ltd.) as the coating solution for the spacer was printed into dots by screen printing. The high-pressure mercury lamp is irradiated with ultraviolet rays, so that spacers with a diameter of 50 μm and a height of 8 μm are arranged at intervals of 1 mm.

Next, the upper electrode plate and the lower electrode plate were arranged in such a manner that the conductive films faced each other, and the edges were adhered using two sides of a thickness of 30 μm and a width of 3 mm, followed by adhesive tape to produce Examples 1 to 4 and Comparative Examples 1 to 3. Resistive film touch panel.

The obtained resistive film type touch panel was mounted on a commercially available ultra-high-definition liquid crystal display device (pixel density 350 ppi), and the presence or absence of glare was visually evaluated. As a result, the glare of the touch panels of Examples 1 to 4 was suppressed. There is also little reflection of outside light and good visibility. In addition, the resolution of the ultra-high-definition images of the touch panels of Examples 1 to 4 is not damaged, and the contrast in a bright room environment is also good. On the other hand, the glare of the touch panels of Comparative Examples 1 to 2 is obvious. Furthermore, the touch panel of Comparative Example 3 reflects external light, and the visibility is poor.

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 of 350 ppi) were laminated through a transparent adhesive to produce Examples 1 to 4 and Comparative Examples 1 to 3. The display device. Furthermore, when bonding, the concave-convex surface of the optical sheet is directed to the side opposite to the display element.

The glare of the obtained display device was evaluated visually. As a result, the glare of the display devices of Examples 1 to 4 was suppressed, the reflection of external light was also low, and the visibility was good. In addition, the resolution of the ultra-high-definition images of the display devices of Examples 1 to 4 is not damaged, and the contrast in a bright room environment is also good. On the other hand, the glare of the display devices of Comparative Examples 1 to 2 is obvious. Furthermore, the display device of Comparative Example 3 reflects outside light and has poor visibility.

1‧‧‧resistive film touch panel

11‧‧‧Transparent substrate

12‧‧‧Transparent conductive film

13‧‧‧ spacer

Claims (7)

A touch panel having an optical sheet as a constituent member, the optical sheet has a concave-convex shape on a surface, and the optical sheet satisfies the following conditions A-1 and A-2, or satisfies the following conditions B-1 and B-2 And B-3, the optical sheet is used for the front surface of the display element with a pixel density of 300 ppi or more; condition A-1: dividing the uneven surface into a measurement area of 64 μm square, and calculating the three-dimensional arithmetic average roughness of each measurement area Degree SRa, and when calculating the standard deviation σ _SRa of the three-dimensional arithmetic average roughness of the entire measurement area, σ _SRa is 0.050 μm or less; Condition A-2: the surface of the concave-convex shape is divided into a measurement area of 64 μm square to obtain The three-dimensional arithmetic average roughness SRa of each measurement area, and the average SRa _AVE of the three-dimensional arithmetic average roughness of the entire measurement area is calculated, the SRa _AVE is 0.100 μm or more; Condition B-1: According to JIS K7374, the image clarity (image clarity) The width of the optical comb of the measuring instrument is 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm. The transmission image clearness of the optical sheet is measured; The transmission image clarity when the comb width is 0.125mm is set to C _0.125 , the transmission image clarity when the optical comb width is 0.25mm is set to C _0.25 , and the transmission image clarity when the optical comb width is 0.5mm Set to C _0.5 , set the transmission image clarity when the width of the optical comb is 1.0 mm to C _1.0 , and set the transmission image clarity when the width of the optical comb to 2.0 mm to C _2.0 , C _0.125 , C _0.25 The difference between the maximum and minimum values of C _0.5 and C _1.0 is within 6.0%; Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more; Condition B-3: C _0.125 is 30.0% or more. For example, the touch panel of the first patent application, the internal haze of the optical sheet is 15~ 40%. A display device comprising an optical sheet on the front surface of a display element with a pixel density of 300 ppi or more, the optical sheet has a concave-convex shape on the surface, and the optical sheet satisfies the following conditions A-1 and A-2, or satisfies the following Conditions B-1, B-2, and B-3 described above; Condition A-1: The surface of the uneven shape is divided into 64 μm square measurement areas, and the three-dimensional arithmetic average roughness SRa of each measurement area is calculated to calculate the entire When the standard deviation of the three-dimensional arithmetic average roughness of the measurement area is σ _SRa , σ _SRa is less than 0.050 μm; Condition A-2: The three-dimensional arithmetic of each measurement area is obtained by dividing the uneven surface into a measurement area of 64 μm square when the average roughness SRa, calculates the three-dimensional arithmetic average roughness entire measuring area average SRa _AVE, SRa _AVE of 0.100μm or more; condition B-1: according to JIS K7374, the width of the light image clarity measuring device is in the comb 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm at each width to measure the transmission image clarity of the optical sheet; when the width of the optical comb is 0.125mm, the transmission image clarity is set to C _0.125 , the light The clarity of the transmission image when the width of the comb is 0.25mm is set to C _0.25 , the clarity of the transmission image when the width of the optical comb is 0.5mm is set to C _0.5 , and the clarity of the transmission image when the width of the optical comb is 1.0mm Set to C _1.0 , and the transmission image clarity when the width of the optical comb is 2.0mm is set to C _2.0 , the difference between the maximum and minimum values of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%; Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more; Condition B-3: C _0.125 is 30.0% or more. An optical sheet having a concave-convex shape on the surface, the optical sheet satisfying the following conditions A-1 and A-2, or satisfying the following conditions B-1, B-2 and B-3, the optical sheet is used for pixel density The front side of the display device above 300ppi, condition A-1: dividing the uneven surface into 64μm square measurement areas, calculating the three-dimensional arithmetic average roughness SRa of each measurement area, and calculating the three-dimensional arithmetic average of the entire measurement area When the standard deviation of roughness σ _SRa , σ _SRa is 0.050 μm or less; Condition A-2: The three-dimensional arithmetic average roughness SRa of each measurement area is obtained by dividing the surface of the uneven shape into 64 μm square measurement areas, and When calculating the average SRa _AVE of the three-dimensional arithmetic average roughness of the entire measurement area, the SRa _AVE is above 0.100 μm; Condition B-1: According to JIS K7374, the width of the optical comb in the image clarity measuring device is 0.125 mm, 0.25 mm, The transmission image clarity of the optical sheet is measured at each width of 0.5mm, 1.0mm and 2.0mm; when the width of the optical comb is 0.125mm, the transmission image clarity is set to C _0.125 , and the width of the optical comb is 0.25mm The clarity of the transmission image at the time is set to C _0.25 , the clarity of the transmission image when the width of the optical comb is 0.5mm is set to C _0.5 , and the clarity of the transmission image when the width of the optical comb is 1.0mm is set to C _1.0 , and When the clarity of the transmission image when the width of the optical comb is 2.0 mm is set to C _2.0 , the difference between the maximum and minimum values of C _0.125 , C _0.25 , C _0.5 and C _1.0 is within 6.0%; Condition B-2: C The difference between _2.0 and C _1.0 is 10.0% or more; Condition B-3: C _0.125 is 30.0% or more. For example, the optical sheet of patent application scope item 4, in which the internal haze of the optical sheet is 15-40%. An optical sheet screening method, which screens optical sheets having a concave-convex shape on the surface, the method screens those satisfying the following conditions A-1 and A-2, or satisfying the following conditions B-1, B-2 and B-3 As an optical sheet, the optical sheet is used for the front surface of a display element with a pixel density of 300 ppi or more; Condition A-1: The three-dimensional arithmetic average roughness of each measurement area is obtained by dividing the uneven surface into 64 μm square measurement areas SRa, and when calculating the standard deviation σ _SRa of the three-dimensional arithmetic average roughness of the entire measurement area, σ _SRa is 0.050 μm or less, condition A-2: the surface of the uneven shape is divided into a measurement area of 64 μm square, and each The three-dimensional arithmetic average roughness SRa of the measurement area, and the average SRa _AVE of the three-dimensional arithmetic average roughness of the entire measurement area is calculated, the SRa _AVE is 0.100 μm or more; Condition B-1: According to JIS K7374, in the image clarity measuring instrument The width of the optical comb is 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm. The transmission image clarity of the optical sheet is measured; when the width of the optical comb is 0.125mm, the transmission image clarity is set to C _0.125 , set the transmission image clarity when the width of the optical comb is 0.25 mm to C _0.25 , set the transmission image clarity when the width of the optical comb is 0.5 mm to C _0.5 , and set the width of the optical comb to 1.0 mm The transmission image clarity is set to C _1.0 , and when the optical comb width is 2.0mm, the transmission image clarity is set to C _2.0 , the difference between the maximum and minimum values of C _0.125 , C _0.25 , C _0.5, and C _1.0 Within 6.0%; Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more; Condition B-3: C _0.125 is 30.0% or more. A method for manufacturing an optical sheet, which is manufactured on an optical sheet having a concave-convex shape on the surface, the method is such that the optical sheet satisfies the following conditions A-1 and A-2, or the following conditions B-1, B-2 and The optical sheet is manufactured by the method of B-3, which is used for the front surface of the display element with a pixel density of 300 ppi or more; Condition A-1: dividing the uneven surface into a measurement area of 64 μm square to obtain each measurement area 3D arithmetic average roughness SRa, and when calculating the standard deviation σ _SRa of the 3D arithmetic average roughness of the entire measurement area, σ _SRa is 0.050 μm or less; Condition A-2: the surface of the concave-convex shape is divided into 64 μm square For the measurement area, calculate the three-dimensional arithmetic average roughness SRa of each measurement area, and when calculating the average three-dimensional arithmetic average roughness SRa _{AVE of the} entire measurement area, SRa _AVE is 0.100 μm or more; Condition B-1: According to JIS K7374, in The width of the optical comb of the image clarity measuring device is 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm. The transmission image clarity of the optical sheet is measured; when the width of the optical comb is 0.125mm set the transmission image clarity C _0.125, the width of the optical comb to C _0.25 of the transmission image sharpness of 0.25mm, the width of the optical comb to C _0.5 of the time to transmit the image clarity of 0.5mm, the optical comb When the width is 1.0mm, the transmission image clarity is set to C _1.0 , and when the optical comb width is 2.0mm, the transmission image clarity is set to C _2.0 , the maximum of C _0.125 , C _0.25 , C _0.5 and C _1.0 The difference between the value and the minimum value is within 6.0%; Condition B-2: The difference between C _2.0 and C _1.0 is 10.0% or more; Condition B-3: C _0.125 is 30.0% or more.

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