JP6996644B2 - Touch panel, display device, optical sheet and selection method of optical sheet - Google Patents

Description

The present invention relates to a touch panel, a display device, an optical sheet, and a method for selecting an optical sheet.

In recent years, a display device with a touch panel having a touch panel mounted on the display device has rapidly become widespread.
Such a display device with a touch panel has a size of medium size or less (20 inch or less to 15 inch A4 type, less than 15 inch to 11 inch or more B5 type), especially small size or less (11 inch or less) and is convenient to carry. Therefore, it is often used outdoors or in a car where sunlight is incident on the screen. Therefore, it is expected that the surface of the touch panel is provided with antiglare property for the purpose of preventing the reflection of sunlight.
As an optical sheet for imparting antiglare property, for example, Patent Document 1 has been proposed.

Japanese Unexamined Patent Publication No. 2013-178534

Patent Document 1 is excellent in antiglare property against indoor lighting. However, the anti-glare property against sunlight (outdoor anti-glare property) is not sufficient.
Further, the touch panel in recent years enables not only moving a finger in one direction but also various operations such as enlarging / reducing the screen on the touch panel. If an optical sheet having a high level of antiglare property is used as the surface material of the touch panel, there is a problem that the operability of the touch panel as described above tends to deteriorate.
Patent Document 1 does not consider both outdoor anti-glare property and touch panel operability.
In addition, the anti-glare film placed on the surface of large-screen TVs and PC monitors currently on the market considers not only the operability of the touch panel but also the anti-glare property against sunlight (outdoor anti-glare property). Not done.

The present invention has been made in view of such circumstances, and is a touch panel, a display device, which has outdoor anti-glare properties, can suppress deterioration of resolution, and has excellent touch panel operability. It is an object of the present invention to provide an optical sheet and a method for selecting an optical sheet.

In order to solve the above problems, the present invention provides the following touch panels [1] to [8], a display device, an optical sheet, and a method for selecting an optical sheet.

[1] A touch panel having irregularities on the surface on the operator side, in which a scratch needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the irregularities, and a vertical load of 100 g is applied to the scratch needles. The static friction coefficient applied to the scratch needle when making one round trip of a length of 10 mm one way at a speed of 10 mm / sec is μs ₁₀ , and a scratch needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness. When the static friction coefficient applied to the scratch needle is μs ₂₀ when the scratch needle is reciprocated once in a length of 10 mm one way at a speed of 20 mm / sec while applying a vertical load of 100 g, μs ₁₀ and μs ₂₀ . Satisfies the following condition (A1), and the unevenness has the following condition (A2) as the arithmetic average roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm. A touch panel that meets the requirements.
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
[2] A display device having irregularities on the outermost surface of the display element on the emission surface side, in which a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the irregularities to scratch the irregularities. The static friction coefficient applied to the scratch needle when one reciprocating a length of 10 mm one way at a speed of 10 mm / sec while applying a vertical load of 100 g to the needle is μs ₁₀ , and the unevenness is made of sapphire with a tip radius of 0.3 mm. The static friction coefficient applied to the scratch needle when the scratch needle was brought into vertical contact and the scratch needle was reciprocated once at a speed of 20 mm / sec with a vertical load of 100 g was set to μs ₂₀ . At that time, μs ₁₀ and μs ₂₀ satisfy the following condition (A1), and the unevenness is the arithmetic average roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm. However, a display device that satisfies the following condition (A2).
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
[3] An optical sheet having irregularities on one surface, in which a scratch needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the irregularities, and a vertical load of 100 g is applied to the scratch needles to 10 mm. The static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way at a speed of / second is μs ₁₀ , and a scratch needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness. When the static friction coefficient applied to the scratch needle is μs ₂₀ when the scratch needle is reciprocated once in a length of 10 mm one way at a speed of 20 mm / sec while applying a vertical load of 100 g, μs ₁₀ and μs ₂₀ are obtained. The following condition (A1) is satisfied, and the unevenness has the following condition (A2) as the arithmetic average roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm. Meet, optical sheet.
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
[4] A method for selecting an optical sheet having irregularities on one surface, in which a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the irregularities, and a vertical load of 100 g is applied to the scratching needle. The static friction coefficient applied to the scratch needle when making one round trip of a length of 10 mm one way at a speed of 10 mm / sec while applying is μs ₁₀ , and a scratch needle made of sapphire with a tip radius of 0.3 mm is vertically placed on the uneven surface. When the static friction coefficient applied to the scratch needle is μs ₂₀ when the scratch needle is brought into contact with each other and reciprocates once in a length of 10 mm one way at a speed of 20 mm / sec while applying a vertical load of 100 g to the scratch needle, μs ₁₀ and The arithmetic average roughness (Ra _2.5 ) of JIS B0601: 1994 when μs ₂₀ satisfies the following condition (A1) and the cutoff value is 2.5 mm is the following condition (Ra 2.5). A method for selecting an optical sheet that satisfies A2) as an optical sheet located at the top of the touch panel.
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)

[5] A touch panel having irregularities on the surface on the operator side, wherein the irregularities satisfy the following conditions (B1) and (B2).
Condition (B1): A scratching needle made of sapphire having a tip radius of 0.3 mm is vertically brought into contact with the unevenness, and a one-way length of 10 mm is applied at a speed of 5 mm / sec while applying a vertical load Tg to the scratching needle. The static friction coefficient μs and the dynamic friction coefficient μk applied to the scratch needle when one reciprocation is performed are measured. In a graph in which the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, plots in the range of the vertical load of 100 to 1000 g are plotted by the minimum square method. When approximated by a linear line, the slope of the linear line is negative.
Condition (B2): The unevenness has an arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 of 0.10 μm or more and 0.60 μm or less when the cutoff value is 2.5 mm.
[6] A display device having irregularities on the outermost surface of the display element on the exit surface side, wherein the irregularities satisfy the following conditions (B1) and (B2).
Condition (B1): A scratching needle made of sapphire having a tip radius of 0.3 mm is vertically brought into contact with the unevenness, and a one-way length of 10 mm is applied at a speed of 5 mm / sec while applying a vertical load Tg to the scratching needle. The static friction coefficient μs and the dynamic friction coefficient μk applied to the scratch needle when one reciprocation is performed are measured. In a graph in which the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, plots in the range of the vertical load of 100 to 1000 g are plotted by the minimum square method. When approximated by a linear line, the slope of the linear line is negative.
Condition (B2): The unevenness has an arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 of 0.10 μm or more and 0.60 μm or less when the cutoff value is 2.5 mm.
[7] An optical sheet having irregularities on one surface, wherein the irregularities satisfy the following conditions (B1) and (B2).
Condition (B1): A scratching needle made of sapphire having a tip radius of 0.3 mm is vertically brought into contact with the unevenness, and a one-way length of 10 mm is applied at a speed of 5 mm / sec while applying a vertical load Tg to the scratching needle. The static friction coefficient μs and the dynamic friction coefficient μk applied to the scratch needle when one reciprocation is performed are measured. In a graph in which the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, plots in the range of the vertical load of 100 to 1000 g are plotted by the minimum square method. When approximated by a linear line, the slope of the linear line is negative.
Condition (B2): The unevenness has an arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 of 0.10 μm or more and 0.60 μm or less when the cutoff value is 2.5 mm.
[8] A method for selecting an optical sheet, which has irregularities on one surface and the irregularities satisfy the following conditions (B1) and (B2) as an optical sheet located at the top of the touch panel. ..
Condition (B1): A scratching needle made of sapphire having a tip radius of 0.3 mm is vertically brought into contact with the unevenness, and a one-way length of 10 mm is applied at a speed of 5 mm / sec while applying a vertical load Tg to the scratching needle. The static friction coefficient μs and the dynamic friction coefficient μk applied to the scratch needle when one reciprocation is performed are measured. In a graph in which the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, plots in the range of the vertical load of 100 to 1000 g are plotted by the minimum square method. When approximated by a linear line, the slope of the linear line is negative.
Condition (B2): The unevenness has an arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 of 0.10 μm or more and 0.60 μm or less when the cutoff value is 2.5 mm.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for selecting a touch panel, a display device, an optical sheet, and an optical sheet, which have outdoor antiglare properties, can suppress deterioration of resolution, and have excellent touch panel operability. be able to.

It is sectional drawing which shows one Embodiment of the resistance film type touch panel of this invention. It is sectional drawing which shows one Embodiment of the capacitive touch panel of this invention. It is a figure explaining the calculation method of the average inclination angle θa. In the unevenness of the optical sheet of the present invention, when the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, the vertical load is in the range of 100 to 1000 g. It is a graph which shows an example of the approximate linear line obtained by the least squares method from a plot.

Hereinafter, the touch panel, the display device, the optical sheet, and the method for selecting the optical sheet of the present invention will be described by taking Embodiment A and Embodiment B as examples.
<Embodiment A>
[Touch panel]
The touch panel of the embodiment A is a touch panel having irregularities on the surface on the operator side.
When a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the above unevenness, and a vertical load of 100 g is applied to the scratching needle, the scratching needle is reciprocated once at a speed of 10 mm / sec. The static friction coefficient applied to the scratch needle is μs ₁₀ , and a scratch needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness, and a vertical load of 100 g is applied to the scratch needle at a speed of 20 mm / sec. When the static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way is μs ₂₀ , μs ₁₀ and μs ₂₀ satisfy the following condition (A1), and
The unevenness is such that the arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A2).
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
In the A embodiment, the "surface on the operator side" refers to a surface that the operator actually touches and operates when operating the touch panel.

Examples of the touch panel include a capacitive touch panel, a resistance film type touch panel, an optical touch panel, an ultrasonic touch panel, an electromagnetic induction type touch panel, and the like.
These touch panels have a transparent base material such as a glass base material and a plastic film base material, and unevenness for imparting antiglare may be formed on the transparent base material. The touch panel of the embodiment A has, for example, an optical sheet described later as a member having irregularities on such a transparent base material at the uppermost portion.

As shown in FIG. 1, the resistance film type touch panel 1 is not shown in the basic configuration in which the conductive films 12 of the pair of upper and lower transparent substrates 11 having the conductive film 12 are arranged via the spacer 13 so as to face each other. The circuit is connected. In the case of the resistance film type touch panel, in the embodiment A, an optical sheet described later is used as the upper transparent substrate. As described above, by using the optical sheet described later as the upper transparent substrate of the resistance film type touch panel, it is possible to impart outdoor antiglare property to the touch panel due to the uneven shape of the optical sheet, and the operability of the touch panel is excellent. Can be considered. In addition, it is possible to suppress a decrease in resolution.
The optical sheet may be used as a lower transparent substrate together with an upper transparent substrate.

Examples of the capacitance type touch panel include a surface type and a projection type, and the projection type is often used. The projection type capacitive touch panel is formed by connecting a circuit to a basic configuration in which an X-axis electrode and a Y-axis electrode orthogonal to the X-axis electrode are arranged via an insulator. More specifically, the basic configuration will be described in a mode in which the X-axis electrode and the Y-axis electrode are formed on different surfaces on one transparent substrate, and the X-axis electrode, the insulator layer, and Y are formed on one transparent substrate. An embodiment in which the axis electrodes are formed in this order, as shown in FIG. 2, an X-axis electrode 22 is formed on one transparent substrate 21, a Y-axis electrode 23 is formed on another transparent substrate 21, and an adhesive is used. Examples thereof include a mode of laminating via the layer 24 and the like. Further, as an example of these basic embodiments, there is an embodiment in which another transparent substrate is laminated.
In the case of the capacitive touch panel, in the embodiment A, an optical sheet described later is used as the uppermost transparent substrate. As described above, by using the optical sheet described later for the transparent substrate at the top of the capacitive touch panel, it is possible to impart outdoor antiglare property to the touch panel due to the uneven shape of the optical sheet, and the operability of the touch panel. Can be made excellent. In addition, it is possible to suppress a decrease in resolution.
A touch panel as described above is used, for example, as an on-cell touch panel installed on a display element.

(Optical sheet)
The optical sheet of the embodiment A has irregularities on one surface, and the irregularities satisfy the above conditions (A1) and (A2).
Touch panels may require different operating speeds. In the condition (A1), when μs ₂₀ / μs ₁₀ is less than 0.70, the operation feeling of screen scrolling cannot be obtained and / or the enlargement / reduction operation cannot be performed smoothly. If it exceeds 1.75, the scroll operation cannot be performed smoothly and / or the operation feeling of enlargement / reduction cannot be obtained.
On the other hand, when the optical sheet of the embodiment A satisfies the condition (A1), the degree of finger catching at the start of the operation can be made the same in any operation of the touch panel, and the operability can be improved. can.
The condition (A1) preferably satisfies 0.80 ≦ μs ₂₀ / μs ₁₀ ≦ 1.60, more preferably 0.85 ≦ μs ₂₀ / μs ₁₀ ≦ 1.25, and more preferably 0.85 ≦ μs. It is more preferable to satisfy ₂₀ / μs ₁₀ ≦ 1.15.
In the embodiment A, the static friction coefficient is the peak of the first frictional force that becomes equal to or greater than the dynamic friction coefficient with the passage of measurement time from the frictional force of 0.

Further, from the viewpoint of improving operability, μs ₂₀ and μs ₁₀ are preferably in the following ranges. μs ₂₀ is preferably 0.10 to 0.26, more preferably 0.11 to 0.25, and even more preferably 0.12 to 0.24. μs ₁₀ is preferably 0.12 to 0.18, more preferably 0.13 to 0.17, and even more preferably 0.14 to 0.16.

Further, in the condition (A2), the cutoff value is 2.5 mm. The cutoff value is a value indicating the degree to which the swell component is cut from the cross-sectional curve composed of the roughness component (high frequency component) and the swell component (low frequency component). In other words, the cutoff value is a value indicating the fineness of the filter that cuts the waviness component (low frequency component) from the cross-sectional curve. When the cutoff value is large, the filter is coarse, so that the large swell of the swell component is cut, but the small swell is not cut. On the other hand, if the cutoff value is small, most of the waviness component will be cut because the filter is fine. In JIS B0633 referred to by JIS B0601, the cutoff value (reference length) is 0.8 mm when the arithmetic mean roughness Ra is 0.1 to 2 μm. Therefore, according to JIS B0633, in the case of Ra under the above condition (A2), it is standard that the cutoff value (reference length) is 0.8 mm.
However, not only the roughness component (high frequency component) but also the swell component (low frequency component) affects the tactile sensation during operation, outdoor anti-glare property, and resolution, so the cutoff value (reference length) When is set to 0.8 mm, the degree to which the undulation component (low frequency component) of the roughness curve is cut becomes large, and the operation is more susceptible to low frequencies than the outdoor antiglare and resolution. The tactile sensation may not be evaluated. Therefore, in the embodiment A, the cutoff value of the condition (A2) is set to 2.5 mm.

The condition (A2) is that the arithmetic mean roughness Ra _2.5 is 0.10 μm or more and 0.60 μm or less. When Ra _2.5 is less than 0.10 μm, light scattering is insufficient and the antiglare property is lowered. In addition, the contact area of the finger with the surface of the optical sheet increases, and the tactile sensation (slip sensation) deteriorates. When Ra _2.5 exceeds 0.60 μm, the smoothness during operation is impaired, and the contrast and resolution are deteriorated. From the viewpoint of tactile sensation during operation, outdoor antiglare property, and resolution, the condition (A2) preferably satisfies 0.15 μm ≤ Ra _2.5 ≤ 0.60 μm, and 0.25 μm ≤ Ra _2.5 . It is more preferable to satisfy ≤0.55 μm.
Further, when the arithmetic average roughness Ra _2.5 is 0.10 μm or more, the gradation-like color unevenness peculiar to the retardation value of the transparent substrate can be made less noticeable. The gradation-like color unevenness peculiar to the retardation value is the color unevenness of the rainbow pattern generated in the light passing through the transparent substrate having the retardation value, and such color unevenness is, for example, a polarizing plate or a predetermined color unevenness. It is observed when light that has passed through a transparent substrate having a retardation value is visually recognized through polarized sunglasses.
By satisfying the conditions (A3) to (A5) described later in addition to the above condition (A2), the above-mentioned condition (A1) can be more easily satisfied. In particular, when Ra _2.5 is 0.25 μm or more, it is possible to make the gradation-like color unevenness less noticeable for a display element having a wide color gamut, for example.

Further, the unevenness has the following conditions (A3) under the conditions (A3) of the ten-point average roughness (Rz _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the above-mentioned Ra _2.5 . It is preferable to satisfy.
5.7 ≤ Rz _2.5 / Ra _2.5 (A3)

The arithmetic mean roughness Ra is a value obtained as an even elevation by integrating the absolute values of the peaks and valleys of the roughness curve of the evaluation length and dividing by the evaluation length. On the other hand, the ten-point average roughness Rz is a roughness curve having an evaluation length of N times the sampling length equal to the cutoff value divided into N equal parts, and the height from the first place to the fifth place for each section. It is the arithmetic mean value of N Rz'when the interval Rz'between the average elevation of the mountaintop and the average elevation of the valley bottom at the depths from the 1st to the 5th is calculated. That is, Ra is the average value of the elevations of the entire roughness curve, while Rz is the average of the elevations when focusing on the 5 points at the high points and the 5 points at the low points in the roughness curve. .. Therefore, when the roughness curve does not have randomness, Ra and Rz are substantially the same, but when the roughness curve has randomness, Rz is larger than Ra. Therefore, Rz / Ra is an index showing the randomness of the roughness curve.

When Rz _2.5 / Ra _2.5 is 5.7 or more, the randomness of the roughness curve is improved, the contact area of the finger with the optical sheet surface is reduced, and the tactile sensation is improved. Further, by improving the randomness of the roughness curve, there is a tendency that the color unevenness of the gradation tone can be made less noticeable for the display element having a wide color gamut. From the viewpoint of tactile sensation (slip sensation) and resolution, it is preferable that the roughness is not random more than necessary.
The condition (A3) more preferably satisfies 6.0 ≤ Rz _2.5 / Ra _2.5 ≤ 10.0, and satisfies 6.5 ≤ Rz _2.5 / Ra _2.5 ≤ 9.5. Is even more preferable, and it is even more preferable to satisfy 7.0 ≤ Rz _2.5 / Ra _2.5 ≤ 9.0.

The Rz _2.5 of the unevenness is preferably 0.50 to 4.30 μm, more preferably 1.00 to 4.00 μm, and further preferably 2.00 to 4.00 μm. preferable. When Rz _2.5 is 0.50 μm or more, the touch panel can be imparted with outdoor antiglare property, and the tactile sensation (slippery sensation) can be further improved. When Rz _2.5 is 4.30 μm or less, the occurrence of glare can be suppressed, and the smoothness during operation is not impaired.
When Rz _2.5 is 2.00 μm or more, it is possible to make the color unevenness of the gradation tone peculiar to the retardation value of the transparent substrate, for example, a display element having a wide color gamut less noticeable.

Further, for the unevenness, it is preferable that the local peak average interval (S _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A4).
S _2.5 ≤ 70 μm (A4)

When the local average interval (S _2.5 ) is 70 μm or less, the contact area of the finger with the optical sheet surface is reduced and the tactile sensation (slip sensation) can be improved.
The condition (A4) is more preferably S _2.5 ≤ 65 μm, further preferably 20 μm ≤ S _2.5 ≤ 60 μm, and even more preferably 30 μm ≤ S _2.5 ≤ 55 μm.

Further, in the unevenness, the ten-point average roughness (Rz _0.8 ) of JIS B0601: 1994 when the cutoff value is 0.8 mm and the above-mentioned Rz _2.5 satisfy the following conditions (A5). It is preferable to meet.
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.20 μm (A5)

As described above, the cutoff value is a value indicating the degree to which the swell component is cut from the cross-sectional curve composed of the roughness component (high frequency component) and the swell component (low frequency component). Therefore, it can be said that Rz _2.5 -Rz _0.8 is an index of the degree of influence of the waviness component on Rz.
When the condition (A5) is satisfied, the coefficient of static friction can be easily set to the same level depending on whether the unevenness is touched at a low speed or the unevenness is touched at a high speed. The touch panel operation can be roughly divided into an operation of scrolling the screen and an operation of enlarging or reducing the display. In the former operation and the latter operation, the former operation tends to move the finger faster. The ease with which the finger is caught by the swell component differs depending on the speed at which the finger is moved. That is, when the condition (A5) is satisfied, the degree of finger catching (static friction coefficient) at the start of the operation can be easily set to the same level in any operation of the touch panel. Further, by setting Rz _2.5 to Rz _0.8 within the above range, glare can be easily suppressed.

The condition (A5) is more preferably 0.15 μm ≤ Rz _2.5 -Rz _0.8 ≤ 0.80 μm, and more preferably 0.20 μm ≤ Rz _2.5 -Rz _0.8 ≤ 0.50 μm. More preferred.
From the viewpoint of making the gradation-like color unevenness peculiar to the retardation value of the transparent substrate less noticeable, Rz _2.5 -Rz _0.8 is preferably more than 0.50 μm, more than 0.80 μm. Is more preferable.

From the viewpoint of making it easy to make the degree of finger catching (static friction coefficient) at the start of operation the same in any operation of the touch panel, Rz _2.5 / Rz _0.8 must satisfy the following conditions for the unevenness. preferable.
Rz _2.5 / Rz _0.8 ≤ 1.50
Furthermore, Rz _2.5 / Rz _0.8 is 1.20 or more and 1.50 or less from the viewpoint of suppressing glare and making the gradation-like color unevenness peculiar to the retardation value of the transparent substrate less noticeable. It is more preferably 1.25 or more and 1.35 or less.

Further, it is preferable that the maximum height (Ry _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following conditions for the unevenness.
0.60 μm ≤ Ry _2.5 ≤ 5.0 μm
When Ry _2.5 is 5.0 μm or less, it is possible to prevent the finger from being caught during operation and to improve the tactile sensation. In addition, it is possible to further prevent the occurrence of glare. When Ry _2.5 is 0.60 μm or more, outdoor antiglare property can be imparted.
Further, Ry _2.5 is more preferably 1.0 μm or more and 4.7 μm or less, and 1.2 μm or more and 4.5 μm or less, from the viewpoint of facilitating the satisfaction of the conditions (A6) and (A7) described later. Is even more preferable.

Further, it is preferable that the above-mentioned (Ry _2.5 ) and the above-mentioned Rz _2.5 satisfy the following condition (A6).
Ry _2.5 / Rz _2.5 ≤ 1.5 (A6)
When Ry _2.5 / Rz _2.5 is 1.5 or less, it is possible to prevent the finger from being caught during operation and to improve the tactile sensation. In addition, it is possible to further prevent the occurrence of glare, and it is possible to easily impart outdoor anti-glare properties.
Ry _2.5 / Rz _2.5 is more preferably 1.10 or more and 1.40 or less, and further preferably 1.18 or more and 1.38 or less.

Further, it is preferable that the average inclination angle (θa _2.5 ) of the unevenness when the cutoff value is 2.5 mm satisfies the following conditions for the unevenness.
1.0 ° ≤ θa _2.5 ≤ 5.5 °
When θa _2.5 is 1.0 ° or more, the touch panel can be provided with outdoor anti-glare properties, and the tactile sensation (slip sensation) during operation can be further improved. When θa _2.5 is 5.5 ° or less, it is possible to suppress a decrease in contrast and achieve both outdoor anti-glare property and contrast. It is more preferable that θa _2.5 satisfies 1.3 ° ≤ θa _2.5 ≤ 4.5 °, and even more preferably 2.0 ° ≤ θa _2.5 ≤ 4.0 °. Further, when θa _2.5 is 1.3 ° or more, the gradation-like color unevenness peculiar to the retardation value of the transparent substrate can be made inconspicuous. Further, when the temperature is 2.0 ° or more, it is possible to make the gradation-like color unevenness less noticeable for a display element having a wide color gamut, for example.
Here, the "average inclination angle θa" is a value defined in the instruction manual (revised 1995.07.20) of the surface roughness measuring instrument (trade name: SE-3400) manufactured by Kosaka Research Institute. , As shown in FIG. 3, the arctangent θa = tan ^-1 {(h ₁ + h ₂ + h) of the sum of the heights of the convex portions existing in the reference length L (h ₁ + h ₂ + h ₃ + ... + h _n ). ₃ + ... + h _n ) / L}.

［式（Ａ）中、「Ｌ」は基準長さを示し、「ｄｙ／ｄｘ」は、粗さ曲線の各単位区間の傾きを示す。］
なお、「基準長さ」とは「カットオフ値」を意味する。すなわち、カットオフ値が０．８ｍｍの場合は基準長さが０．８ｍｍである。また、単位測定区間とは、カットオフ値をサンプリング数で除した長さの区間である。サンプリング数は１５００とする。 Further, θa can be calculated from the following equation (A).

[In the formula (A), "L" indicates the reference length, and "dy / dx" indicates the slope of each unit interval of the roughness curve. ]
The "reference length" means a "cutoff value". That is, when the cutoff value is 0.8 mm, the reference length is 0.8 mm. The unit measurement section is a section having a length obtained by dividing the cutoff value by the number of samplings. The number of samplings is 1500.

Further, as for the unevenness, it is preferable that the above (θa _2.5 ) and the above Ry _2.5 / Rz _2.5 satisfy the following condition (A7).
0.8 ≤ θa _2.5 / (Ry _2.5 / Rz _2.5 ) ≤ 5.0 (A7)
If θa _2.5 / (Ry _2.5 / Rz _2.5 ) is within the above range, unevenness with appropriate randomness will occur, and anti-glare, resolution, tactile sensation during operation (slip sensation), and It is possible to improve the balance of being able to make the color unevenness of the gradation tone peculiar to the retardation value of the transparent base material less noticeable.
θa _2.5 / (Ry _2.5 / Rz _2.5 ) is more preferably 1.0 or more and 4.5 or less, and even in the case of a display element having a wide color gamut, gradation-like color unevenness is conspicuous. Since it can be made difficult, it is more preferably 2.0 or more and 4.0 or less.

Further, for the unevenness, it is preferable that the average interval (Sm _2.5 ) of the unevenness of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following conditions.
Sm _2.5 ≤ 160 μm
When Sm _2.5 is 160 μm or less, the contact area of the finger with the surface of the optical sheet is reduced, and the tactile sensation (slip sensation) can be improved. Sm _2.5 is more preferably 150 μm or less, further preferably 145 μm or less. The lower limit is preferably 30 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more.
It should be noted that the smaller the Sm _2.5 , the more the occurrence of glare can be suppressed even in a high-definition display.

Examples of the method for forming the unevenness described above include physical or chemical treatment such as (x1) embossing, sandblasting, and etching, molding by (x2) mold, and formation of an uneven layer by (x3) coating. Among these methods, molding by the mold of (x2) is preferable from the viewpoint of reproducibility of the uneven shape, and formation of the uneven layer by the coating of (x3) is preferable from the viewpoint of productivity and compatibility with various types. be.

Molding with a mold can be performed by producing a mold having a shape complementary to the unevenness, pouring a material for forming the unevenness into the mold, and then removing the mold from the mold. Here, if a material constituting the unevenness is used as the material, the transparent base material is superposed after the material is poured into the mold, and the unevenness is taken out from the mold together with the transparent base material, an optical sheet having the unevenness on the transparent base material is obtained. Can be obtained. Further, if the material constituting the transparent base material is poured into the mold and then taken out from the mold, an optical sheet composed of a single layer of the transparent base material and having irregularities on the surface of the transparent base material can be obtained.
When a curable resin composition (thermosetting resin composition or ionizing radiation curable resin composition) is used as a material to be poured into a mold, it is preferable to cure the curable resin composition before removing it from the mold.
The formation of unevenness by the mold is preferable in that the unevenness shape is excellent in reproducibility.

To form the uneven layer by coating, a coating liquid for forming an uneven layer containing a resin component and particles is applied onto a transparent substrate by a known coating method such as gravure coating or bar coating, and dried as necessary. It can be formed by curing. In order for the concavo-convex layer to satisfy the above-mentioned conditions (A1) and (A2), it is preferable that the film thickness of the concavo-convex layer, the content of particles, and the average particle diameter of the particles are within the ranges described below.

The film thickness of the uneven layer is preferably 1.5 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 7 μm. The thickness of the uneven layer is determined by measuring the thickness at 20 points from a cross-sectional image taken with, for example, a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), and from the average value of the values at the 20 points. Can be calculated. The acceleration voltage of TEM or STEM is preferably 1 to 5 kV, and the magnification is preferably 1000 to 10,000 times.

As the particles, either organic particles or inorganic particles can be used as long as they can form irregularities. Examples of the organic particles include particles made of polymethylmethacrylate, polyacrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluororesin, polyester resin and the like. Can be mentioned. Examples of the inorganic particles include particles made of silica, alumina, zirconia, titania and the like. Among these particles, translucent organic particles and silica particles are preferable from the viewpoint of ease of dispersion control.
The particles may be used alone or in combination of two or more having different materials and particle sizes.

Further, in order to make the gradation-like color unevenness less noticeable even in a display element having a wide color gamut, the particles are preferably irregular particles having a particle diameter equal to or larger than the wavelength of visible light. Since the uneven layer contains amorphous particles, it is possible to suppress gradation-like color unevenness.

The content of the particles is preferably 5 to 25% by mass, more preferably 6 to 22% by mass, and even more preferably 10 to 20% by mass in the total solid content forming the uneven layer. ..

The average particle size of the particles in the concavo-convex layer varies depending on the thickness of the concavo-convex layer and cannot be unequivocally determined. , 1.5 to 8.0 μm, more preferably 2.0 to 6.0 μm. When the particles are agglomerated, it is preferable that the average particle size of the agglomerated particles satisfies the above range.
The average particle diameter of the particles can be calculated by the following operations (y1) to (y3).
(Y1) Select the particles that can be seen most in the observation screen from the image of the cross section taken by using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The acceleration voltage of TEM or STEM is preferably 1 to 30 kV, and the magnification is preferably 5000 to 300,000 times.
(Y2) Particles having the maximum diameter are extracted from the observation image, and the particle diameter of each particle is calculated. The particle size is measured as the distance between straight lines in a combination of two straight lines such that the distance between the two straight lines is maximized when the cross section of the particle is sandwiched between two arbitrary parallel straight lines.
(Y3) The same operation is performed on the observation image on another screen of the same sample, and the value obtained from the number average of the particle diameters for a total of 20 particles is taken as the average particle diameter of the particles.
In the case of agglomerated particles, the maximum diameter portion of the agglomerated agglomerates is regarded as the particle diameter.
Further, the average particle size of the ultrafine particles described later can be calculated by performing the same method as in (y1) to (y3) above. When calculating the average particle size of the ultrafine particles, the acceleration voltage of TEM or STEM is preferably 10 kv to 30 kV, and the magnification is preferably 10,000 to 300,000 times.

From the viewpoint of making it easier for the uneven layer to satisfy the above-mentioned conditions (A1) and (A2), the film thickness of the uneven layer is preferably larger than the average particle diameter of the particles. More specifically, the ratio of [average particle size of particles] / [thickness of uneven layer] is preferably 0.20 to 0.99, and preferably 0.50 to 0.90. More preferred.
Even if the particles have a wide particle size distribution (a single particle having a wide particle size distribution, or a mixed particle having two or more types of particles having different particle size distributions having a wide particle size distribution). However, from the viewpoint of suppressing glare, it is preferable that the particle size distribution is narrow.

Further, as the particles, it is preferable to contain not only micron-order particles as described above but also nano-order ultrafine particles. By containing nano-order ultrafine particles, the uneven layer can easily satisfy the above-mentioned conditions (A1) and (A2). The reason for this is that when ultrafine particles are contained, a gentle slope is formed even in the place where the particles do not exist, and low frequency unevenness (cut at a cutoff value of 0.8 mm, but cut at a cutoff value of 2.5 mm). It is considered that this is because unevenness that is not formed) is formed. When ultrafine particles are contained, the thixotropy of the coating liquid and the drying characteristics of the solvent are affected, and the usual leveling does not occur, so that the above phenomenon is considered to occur.

The ultrafine particles are preferably inorganic fine particles. Examples of the inorganic ultrafine particles include ultrafine particles made of silica, alumina, zirconia, titania and the like. Among these, silica ultrafine particles are preferable from the viewpoint of transparency.
The ultrafine particles preferably have an average primary particle diameter of 1 to 25 nm, and more preferably 5 to 20 nm. Within the above range, the uneven layer tends to satisfy the above-mentioned conditions (A1) and (A2).

As the ultrafine particles, surface-treated ultrafine particles and reactive ultrafine particles into which a reactive group is further introduced are preferable. By introducing the surface treatment, it becomes easy to balance with the organic binder and the solvent in the uneven layer, and the uneven layer can easily satisfy the above-mentioned conditions (A1) and (A2). Examples of such surface-treated ultrafine particles include inorganic ultrafine particles surface-treated with a silane coupling agent. To treat the surface of the inorganic ultrafine particles with a silane coupling agent, a dry method of spraying the silane coupling agent on the inorganic ultrafine particles or a method of dispersing the inorganic ultrafine particles in a solvent and then adding the silane coupling agent to react. Wet method and the like can be mentioned.
When a reactive group is introduced, a polymerizable unsaturated group is preferably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples thereof include ethylenically unsaturated bonds such as (meth) acryloyl group, (meth) acryloyloxy group, vinyl group and allyl group, epoxy group and the like.

The content of the ultrafine particles is preferably 0.2 to 60% by mass in the total solid content forming the uneven layer. The amount can be adjusted depending on the purpose of using the ultrafine particles, and is preferably 15 to 50% by mass from the viewpoint of improving hardness and scratch resistance, and 0.4 to 10% by mass from the viewpoint of improving optical characteristics and preparing unevenness. % Is preferable. Further, by setting it within the above range, the leveling property is controlled and the polymerization shrinkage of the uneven layer is suppressed, so that the uneven layer can easily satisfy the above-mentioned conditions (A1) and (A2).
When other particles are contained in the uneven layer, the ratio of the contents of the other particles to the ultrafine particles (content of other particles / content of ultrafine particles) is 0.05 to 3.0. It is preferably 0.1 to 1.5, and more preferably 0.7 or less. By setting it within the above range, the uneven layer can easily satisfy the above-mentioned conditions (A1) and (A2). By aggregating only the ultrafine particles, the particles can be made into μm-order particles and unevenness can be formed.

The resin component of the uneven layer preferably contains a thermosetting resin composition or an ionized radiation curable resin composition, and more preferably contains an ionized radiation curable resin composition from the viewpoint of improving mechanical strength. Among them, it is more preferable to contain 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 cured by heating.
Examples of the thermosetting resin include acrylic resin, urethane resin, phenol resin, urea melamine resin, epoxy resin, unsaturated polyester resin, silicone resin and the like. To the thermosetting resin composition, a curing agent is added to these curable resins as needed.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter, also referred to as “ionizing radiation curable compound”). Examples of the ionizing radiation curable functional group include an ethylenically unsaturated bond group such as a (meth) acryloyl group, a vinyl group and an allyl group, an epoxy group and an oxetanyl group. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferable, a compound having two or more ethylenically unsaturated bond groups is more preferable, and a compound having two or more ethylenically unsaturated bond groups is particularly preferable. Polyfunctional (meth) acrylate compounds are more preferred. As the polyfunctional (meth) acrylate compound, either a monomer or an oligomer can be used.
The ionizing radiation means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking a molecule, and usually, an ultraviolet ray (UV) or an electron beam (EB) is used. Electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion rays can also be used.

Among the polyfunctional (meth) acrylate compounds, the bifunctional (meth) acrylate monomers include ethylene glycol di (meth) acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexane. Didiol diacrylate, dicyclopentenyl di (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol di (meth) acrylate, tricyclodecanediyl dimethylene di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di ( Meta) Acrylate and the like can be mentioned.
Examples of the trifunctional or higher functional (meth) acrylate-based monomer include trimethylol propanetri (meth) acrylate, trimethylol ethanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and penta. Elythritol hexa (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, ditrimethylol propanetetra (meth) Examples thereof include acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate and the like.
Further, the (meth) acrylate-based monomer may be one in which a part of the molecular skeleton is modified, and is modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol and the like. Can also be used.

Examples of the polyfunctional (meth) acrylate-based oligomer include acrylate-based polymers such as urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and polyether (meth) acrylate.
Urethane (meth) acrylates are obtained, for example, by reacting polyhydric alcohols and organic diisocyanates with hydroxy (meth) acrylates.
Further, the preferable epoxy (meth) acrylate is a (meth) acrylate obtained by reacting a (meth) acrylic acid with a trifunctional or higher functional aromatic epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin and the like, and a bifunctional one. (Meta) acrylate obtained by reacting the above aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. with polybasic acid and (meth) acrylic acid, and bifunctional or higher functional aromatic epoxy resin, It is a (meth) acrylate obtained by reacting an alicyclic epoxy resin, an aliphatic epoxy resin or the like with phenols and (meth) acrylic acid.
The ionizing radiation curable compound may be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains an additive such as a photopolymerization initiator or a photopolymerization accelerator.
Examples of the photopolymerization initiator include acetophenone, benzophenone, α-hydroxyalkylphenone, α-aminoalkylphenone, α-hydroxyketone, Michler ketone, benzoin, benzylmethyl ketal, benzoyl benzoate, α-acyl oxime ester, and acylphosphine oxides. , One or more selected from thioxanthones and the like.
Among the above photopolymerization initiators, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone, 2-Hydroxy-2-methyl-1-phenyl-propane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1- It is preferable to select one or more types of ON as appropriate.

The photopolymerization initiator is not limited to the above compounds, and may be any photopolymerization initiator as long as it has the ability to initiate polymerization by ultraviolet rays. These photopolymerization initiators can be used alone or in combination of two or more.
The content of the photopolymerization initiator in the ionizing radiation curable resin composition is not particularly limited, but it is preferably used within the range of 1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the ultraviolet curable compound. Even when a plurality of types are used, it is preferable to use each within the above range.

The photopolymerization initiator preferably has a melting point of 100 ° C. or higher. By setting the melting point of the photopolymerization initiator to 100 ° C. or higher, the photopolymerization initiator remaining during the formation of the transparent conductive film of the touch panel or the heat of the crystallization step is sublimated, and the low resistance of the transparent conductive film is impaired. Can be prevented.
Further, the photopolymerization accelerator can reduce the polymerization inhibition due to air at the time of curing and accelerate the curing rate. For example, from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester and the like. One or more selected species can be mentioned.

Further, it is preferable that the uneven layer forming coating liquid contains a leveling agent. Examples of the leveling agent include a fluorine-based leveling agent, a silicone-based leveling agent, a fluorine-silicone copolymerization-based leveling agent, and the like. Above all, a silicone-based leveling agent is preferably used from the viewpoint of making it easier for the uneven layer to satisfy the above-mentioned conditions (A1) and (A2). Further, the non-reactive type tends to have better touch panel operability than the reactive type.
The amount of the leveling agent added is preferably 0.01 to 5.0% by weight based on the total solid content of the uneven layer.

It is preferable that the unevenness of the optical sheet is treated with antifouling treatment. By applying the antifouling treatment, it is possible to prevent the unevenness from accumulating dirt and impairing the surface shape of the embodiment A. Further, the antifouling treatment with a fluorine-based mold release agent, a silicone-based mold release agent, or the like is preferable because it imparts slipperiness to the unevenness, makes it easier to satisfy the condition (A1), and can improve the tactile sensation.
As means for antifouling treatment, a means for incorporating a mold release agent such as a fluorine-based mold release agent and a silicone-based mold release agent into the uneven layer, and a means for forming a mold release layer on the outermost surface of the optical sheet with the above-mentioned mold release agent. Can be mentioned. When the release agent is contained in the uneven layer, the content of the release agent is preferably 0.5 to 5.0% by mass of the total solid content of the uneven layer.

(Transparent base material)
The transparent substrate used for the optical sheet is preferably one having light transmittance, smoothness, heat resistance, and excellent mechanical strength. Examples of such a transparent base material include polyester, triacetyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulphon, polysulphon, polypropylene, polymethylpentene, polyvinyl chloride, and polyvinyl acetal. , Polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane and plastic films such as amorphous olefin (Cyclo-Olefin-Polymer: COP). The transparent base material may be made by laminating two or more plastic films.
In addition to the above-mentioned plastic films manufactured by general-purpose methods such as melt extrusion molding method: extension molding (inflation method, T-die method), solution casting method: solution casting, and calendering method: calendering, the film has releasability. It may be a film produced by forming a coating film made of a resin such as an ionizing radiation curable resin composition on a substrate and peeling the coating film from the substrate.

Among the above, from the viewpoint of mechanical strength and dimensional stability, stretch-processed, particularly biaxially-stretched polyester (polyethylene terephthalate, polyethylene naphthalate) is preferable. Further, COP and polyester are suitable because they have excellent weather resistance.

The thickness of the transparent substrate is preferably 5 to 300 μm, more preferably 10 to 200 μm, and even more preferably 20 to 130 μm.
In addition to physical treatment such as corona discharge treatment and oxidation treatment, a paint called an anchor agent or a primer may be applied to the surface of the transparent base material in advance in order to improve the adhesiveness.

The transparent substrate preferably has a retardation value of more than 0 nm and less than 3,000 nm, and more preferably more than 20 nm and 2,000 nm or less. The retardation value is a value at a wavelength of 550 nm.
The retardation value of the transparent substrate is the refractive index n _x in the slow-phase axial direction, which is the direction in which the refractive index is the largest in the plane of the transparent substrate, and the direction orthogonal to the slow-phase axial direction in the plane of the transparent substrate. It is expressed by the following formula by the refractive index _ny in the phase-advancing axis direction and the thickness d of the transparent base material, and is so-called “in-plane retardation”.
Restriction value (Re) = (n _x − n _y ) × d
The retardation value can be measured by, for example, the trade names "KOBRA-WR" and "PAM-UHR100" manufactured by Oji Measuring Instruments Co., Ltd.

Normally, when a transparent substrate having a small retardation value is used, gradation-like color unevenness caused by light passing through the transparent substrate is observed (for example, passing through a polarizing plate or a transparent substrate having a predetermined retardation value). It is observed when the emitted light is visually recognized through polarized sunglasses.) However, since the optical sheet used in the touch panel of the embodiment A satisfies the condition (A2), even if a transparent base material having a small retardation value is used, the color unevenness of the gradation tone can be made less noticeable.
It should be noted that the fact that the gradation-like color unevenness can be made inconspicuous even if the retardation value is reduced leads to the fact that the thickness of the transparent base material can be reduced. That is, a transparent base material that produces retardation (for example, a polyester film that is a general-purpose base material) is usually uniaxially stretched to increase the thickness of the base material to increase the retardation value to create a gradation tone. It suppresses the occurrence of color unevenness. However, in the optical sheet used in the touch panel of the embodiment A, even if the thickness of the transparent base material (for example, a polyester film which is a general-purpose base material) is reduced, the gradation-like color unevenness can be made less noticeable.
Furthermore, the fact that the gradation-like color unevenness can be made less noticeable even if the retardation value is reduced is that a plastic film (polyimide film, aramid film) that is out of the selection because it is usually prone to gradation-like color unevenness can be used. Leads to. Polyimide film and aramid film are preferable because they have excellent bending resistance.
In recent years, the color gamut of display elements has tended to expand. A display element having a wide color gamut has a sharp spectral spectrum for each color (R, G, B), and in such a display element, gradation-like color unevenness peculiar to a retardation value is particularly conspicuous. It tends to be easy. The optical sheet used in the touch panel of the embodiment A is preferable in that the gradation-like color unevenness can be made inconspicuous even for a display element having a wide color gamut.

The optical sheet may have a functional layer such as an antireflection layer, an antifouling layer, and an antistatic layer on the uneven surface and / or on the surface opposite to the unevenness. Further, in the case of a configuration having an uneven layer on the transparent base material, a functional layer may be provided between the transparent base material and the uneven layer in addition to the above-mentioned portion.
When another functional layer is laminated on the uneven layer, the unevenness on the outermost surface satisfies the range of the present application. The unevenness may be a single layer or a plurality of layers as long as the outermost surface is within the range of the present application.

The touch panel of the embodiment A is provided with outdoor anti-glare property due to the uneven shape of the optical sheet described above, and has excellent operability. In addition, it is possible to suppress a decrease in resolution.
Therefore, it is preferable that the touch panel of the embodiment A is installed on the exit surface side of the display device of an in-vehicle display device and the display element of a smartphone or tablet (multifunctional mobile terminal) carried when moving such as a train.

[Display device]
The display device of the embodiment A is a display device having irregularities on the outermost surface of the display element on the exit surface side, and the irregularities satisfy the above-mentioned conditions (A1) and (A2).
As the display device of the embodiment A, the same optical sheet as the optical sheet used for the touch panel of the above-described embodiment A can be used as the member having the unevenness on the outermost surface.

Examples of the display element include a liquid crystal display element, an in-cell touch panel liquid crystal display element, an EL display element, a plasma display element, and the like. The liquid crystal display element has a backlight on the back surface of the liquid crystal element.
The in-cell touch panel liquid crystal element incorporates touch panel functions such as a resistance film type, a capacitance type, and an optical type inside a liquid crystal element having a liquid crystal sandwiched between two glass substrates. Examples of the liquid crystal display method of the in-cell touch panel liquid crystal element include an IPS method, a VA method, a multi-domain method, an OCB method, an STN method, and a TSTN method. The in-cell touch panel liquid crystal element is described in, for example, Japanese Patent Application Laid-Open No. 2011-76602 and Japanese Patent Application Laid-Open No. 2011-222009.

The optical sheet can be installed on the exit surface side of the display element in the following order, for example.
(A) Display element / surface protection plate / optical sheet (b) Display element / optical sheet (c) In the case of touch panels (a) and (b) having a display element / optical sheet at the top, the unevenness of the optical sheet is displayed. By arranging the display device so as to face the opposite side of the element, it is possible to impart outdoor antiglare property to the display device. In addition, it is possible to suppress a decrease in the resolution of the display element, and further, it is possible to make it difficult to see scratches on the surface or the display element.
In the case of (c), the display device is a display device with a touch panel provided with a touch panel having an optical sheet at the uppermost portion on the exit surface side of the display element. In this case, the display device can be a display device having excellent operability of the touch panel as well as outdoor anti-glare property and high resolution.
Therefore, the display device of the embodiment A is suitable as an in-vehicle display device and a smartphone or tablet (multifunctional mobile terminal) to be carried when moving such as a train.

As described above, the optical sheet used in the display device of the A embodiment can make the gradation-like color unevenness less noticeable even for a display element having a wide color gamut. Examples of the standard representing the color gamut include "ITU-R Recommendation BT.2020 (hereinafter referred to as" BT.2020 ")" and the like. ITU-R is an abbreviation for "International Telecommunication Union-Radiocommunication Sector" and is an abbreviation for ITU-R Recommendation BT. 2020 is an international standard for the color gamut of Super Hi-Vision.
The display device of the embodiment A is a BT. Even for a display element having a coverage rate of 60% or more in 2020, color unevenness in gradation tone can be made inconspicuous.
<BT. Formula for 2020 coverage>
[Of the area of the CIE-xy chromaticity diagram of the display element, BT. Area overlapping with the area of the 2020 CIE-xy chromaticity diagram / BT. Area of CIE-xy chromaticity diagram of 2020] x 100 (%)

In addition, BT. The "area of the CIE-xy chromaticity diagram" required when calculating the coverage rate of 2020 is the CIE-Yxy color in the red (R) display, the green (G) display, and the blue (B) display. The x and y values of the system are measured, respectively, and calculated from the "red (R) vertex coordinates", "green (G) vertex coordinates", and "blue (B) vertex coordinates" obtained from the measurement results. can. The x-value and y-value of the CIE-Yxy color system can be measured by, for example, a spectral radiance meter CS-2000 manufactured by Konica Minolta.
Display elements with a wide color gamut include three-color independent organic EL display devices (among them, three-color independent organic EL elements with a microcavity structure), and liquid crystal display elements that use quantum dots for the backlight. Examples thereof include a liquid crystal display element using a three-wavelength white LED (a combination of a near-ultraviolet LED and a blue phosphor, a green phosphor, and a red phosphor) as a backlight.

[Optical sheet]
The optical sheet of the embodiment A has irregularities on one surface, and the irregularities satisfy the above-mentioned conditions (A1) and (A2). In the optical sheet of the embodiment A, when another functional layer is laminated on the unevenness, the unevenness on the outermost surface satisfies the range of the present application. The unevenness may be a single layer or a plurality of layers as long as the outermost surface is within the range of the present application.
Examples of the optical sheet of the embodiment A include the same optical sheets used for the touch panel of the above-described embodiment A.

When the optical sheet of the embodiment A is used for the touch panel, the optical sheet is installed so that the surface having irregularities is the surface on the operator side of the touch panel.
In order to satisfy the above-mentioned conditions (A1) and (A2), the optical sheet of the embodiment A is provided at the uppermost portion of the touch panel to impart outdoor antiglare property to the touch panel and to provide operability of the touch panel. Can be made excellent.
Therefore, the optical sheet of the embodiment A can be preferably used on the surface of an in-vehicle display device or the surface of a smartphone or tablet (multifunctional mobile terminal) carried when moving such as a train.

[Method of selecting optical sheets]
The method for selecting an optical sheet according to the embodiment A is an optical sheet having irregularities on one surface, and an optical sheet whose irregularities satisfy the above-mentioned conditions (A1) and (A2) is positioned at the top of the touch panel. It is selected as an optical sheet to be used.

In the method for selecting an optical sheet according to the embodiment A, it is possible to select an optical sheet having good operability, outdoor antiglare property, and high resolution without performing an operability test of the optical sheet. , Product design of optical sheets and quality control can be performed efficiently.

The above-mentioned conditions (A1) and (A2) are indispensable conditions for the determination condition for selecting the optical sheet of the touch panel. The determination condition of the condition (A1) preferably satisfies 0.80 ≦ μs ₂₀ / μs ₁₀ ≦ 1.65, and more preferably 0.85 ≦ μs ₂₀ / μs ₁₀ ≦ 1.55. Further, the determination condition of the condition (A2) preferably satisfies 0.15 μm ≦ Ra _2.5 ≦ 0.60 μm, and more preferably 0.25 μm ≦ Ra _2.5 ≦ 0.55 μm.

In the method for selecting the optical sheet of the touch panel, it is more preferable to set one or more of the following conditions (A3) to (A5) as additional determination conditions from the viewpoint of tactile sensation during operation and outdoor antiglare property. It is more preferable that all of A3) to (A5) are used as additional determination conditions.
5.7 ≤ Rz _2.5 / Ra _2.5 (A3)
S _2.5 ≤ 70 μm (A4)
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.50 μm (A5)
The determination conditions of the conditions (A3) to (A5) are preferably in a suitable numerical range of the optical sheet of the above-described embodiment A.
Further, it is preferable to set other parameters as additional determination conditions.

<Embodiment B>
[Touch panel]
The touch panel of the embodiment B has an uneven surface on the operator side, and the unevenness satisfies the following conditions (B1) and (B2).
Condition (B1): A scratching needle made of sapphire having a tip radius of 0.3 mm is vertically brought into contact with the unevenness, and a one-way length of 10 mm is applied at a speed of 5 mm / sec while applying a vertical load Tg to the scratching needle. The static friction coefficient μs and the dynamic friction coefficient μk applied to the scratch needle when one reciprocation is performed are measured. In a graph in which the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis, plots in the range of the vertical load of 100 to 1000 g are plotted by the minimum square method. When approximated by a linear line, the slope of the linear line is negative.
Condition (B2): The unevenness has an arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 of 0.10 μm or more and 0.60 μm or less when the cutoff value is 2.5 mm.
In the B embodiment, the "surface on the operator side" refers to a surface that the operator actually touches and operates when operating the touch panel.

Examples of the touch panel include a capacitive touch panel, a resistance film type touch panel, an optical touch panel, an ultrasonic touch panel, an electromagnetic induction type touch panel, and the like. These touch panels have a transparent base material such as a glass base material and a plastic film base material, and unevenness for imparting antiglare may be formed on the transparent base material. The touch panel of the embodiment B has, for example, an optical sheet described later as a member having irregularities on such a transparent base material at the uppermost portion.

As shown in FIG. 1, the resistance film type touch panel 1 is not shown in the basic configuration in which the conductive films 12 of the pair of upper and lower transparent substrates 11 having the conductive film 12 are arranged via the spacer 13 so as to face each other. The circuit is connected. In the case of the resistance film type touch panel, in the embodiment B, an optical sheet described later is used as the upper transparent substrate. As described above, by using the optical sheet described later as the upper transparent substrate of the resistance film type touch panel, it is possible to impart outdoor antiglare property to the touch panel due to the uneven shape of the optical sheet, and the operability of the touch panel is excellent. Can be considered. In addition, it is possible to suppress a decrease in resolution.
The optical sheet may be used as a lower transparent substrate together with an upper transparent substrate.

Examples of the capacitance type touch panel include a surface type and a projection type, and the projection type is often used. The projection type capacitive touch panel is formed by connecting a circuit to a basic configuration in which an X-axis electrode and a Y-axis electrode orthogonal to the X-axis electrode are arranged via an insulator. More specifically, the basic configuration will be described in a mode in which the X-axis electrode and the Y-axis electrode are formed on different surfaces on one transparent substrate, and the X-axis electrode, the insulator layer, and Y are formed on one transparent substrate. An embodiment in which the axis electrodes are formed in this order, as shown in FIG. 2, an X-axis electrode 22 is formed on one transparent substrate 21, a Y-axis electrode 23 is formed on another transparent substrate 21, and an adhesive is used. Examples thereof include a mode of laminating via the layer 24 and the like. Further, as an example of these basic embodiments, there is an embodiment in which another transparent substrate is laminated.
In the case of the capacitive touch panel, in the B embodiment, an optical sheet described later is used as the uppermost transparent substrate. As described above, by using the optical sheet described later for the transparent substrate at the top of the capacitive touch panel, it is possible to impart outdoor antiglare property to the touch panel due to the uneven shape of the optical sheet, and the operability of the touch panel. Can be made excellent. In addition, it is possible to suppress a decrease in resolution.
A touch panel as described above is used, for example, as an on-cell touch panel installed on a display element.

(Optical sheet)
The optical sheet of the embodiment B has irregularities on one surface, and the irregularities satisfy the above conditions (B1) and (B2).
FIG. 4 shows a vertical load of 100 to 100 when the ratio (μs / μk) of the static friction coefficient μs to the dynamic friction coefficient μk is plotted on the vertical axis and the vertical load Tg is plotted on the horizontal axis in the unevenness of the optical sheet of the embodiment B. It is a graph which shows the approximate linear line obtained by the least squares method from the plot in the range of 1000 g. As shown in FIG. 4, in the optical sheet of the embodiment B, the inclination of the approximate linear line becomes negative, and the ratio (μs / μk) decreases as the load (vertical load) applied to the unevenness of the optical sheet increases. Become. This means that as the vertical load increases, the unevenness of the optical sheet is more likely to be deformed, and the influence of the unevenness becomes smaller.

When changing the direction of a finger on an optical sheet, for example, when writing a character or drawing a figure, it is often stopped for a moment and then restarted (for example, when changing the direction of the finger). Normally, the movement of the finger is stopped for a moment. Also, the movement of the finger is stopped for a moment when moving the position where the finger is placed.) When the movement of the finger is stopped for a moment and restarted in this way, it is easily affected by the difference between the static friction coefficient μs and the dynamic friction coefficient μk.
When the vertical load is small and the ratio (μs / μk) is too small, the finger is slippery on the optical sheet and it is difficult to change direction. Further, when the vertical load is large and the ratio (μs / μk) is too large, when the finger is turned on the optical sheet, a large load is applied to the finger and it becomes difficult to change the direction.
Therefore, in order to make it easier to change the direction of the finger on the optical sheet, when the vertical load is small, the finger does not slip too much and an appropriate resistance is obtained, and as the vertical load increases, the load applied to the finger is increased. Is required to be suppressed.
In the optical sheet of the embodiment B, by satisfying the above condition (B1), a complicated operation such as changing the direction of a finger on the optical sheet can be satisfactorily performed.
The situations where the load is different are, for example, the situation where the terminal is operated while standing in the train (the operation load at this time is generally light), and the situation where the terminal is placed on the desk and fixed with one hand. (The operation load at this time is generally heavy). That is, by satisfying the condition (B1), it is possible to satisfactorily perform a complicated operation such as changing the direction in a situation where the posture at the time of operation is different and the operation load is different.

In the B embodiment, the dynamic friction coefficient μk means the average value of the dynamic friction coefficient for the entire measurement time. Further, the static friction coefficient μs is set as the first peak of the frictional force that becomes equal to or higher than the dynamic friction coefficient with the passage of measurement time from the frictional force of 0.
The static friction coefficient μs and the dynamic friction coefficient μk can be measured by a friction wear tester (HEIDON NHS2000 manufactured by Shinto Kagaku Co., Ltd.).

When the vertical load is small, for example, the ratio (μs / μk) when the load is 50 to 150 g is preferably 1.58 to 2.50, more preferably 1.70 from the viewpoint of obtaining an appropriate resistance without slipping too much. It is about 2.20. Further, when the vertical load is large, for example, the ratio (μs / μk) when the load is 900 to 1100 g is preferably 1.00 to 1.50, more preferably 1.10 to 1 from the viewpoint of suppressing an excessive load. It is .40.

Further, under the condition (B1), the slope of the approximate linear line is preferably -10.0 × 10 ^-4 to −4.5 × 10 ^-4 , and more preferably −8.5 × 10 ^-4 to −. It is 6.0 × 10 ^-4 . Within the above range, the operability can be improved.

Further, in the condition (B2), the cutoff value is set to 2.5 mm. The cutoff value is a value indicating the degree to which the swell component is cut from the cross-sectional curve composed of the roughness component (high frequency component) and the swell component (low frequency component). In other words, the cutoff value is a value indicating the fineness of the filter that cuts the waviness component (low frequency component) from the cross-sectional curve. When the cutoff value is large, the filter is coarse, so that the large swell of the swell component is cut, but the small swell is not cut. On the other hand, if the cutoff value is small, most of the waviness component will be cut because the filter is fine. In JIS B0633 referred to by JIS B0601, the cutoff value (reference length) is 0.8 mm when the arithmetic mean roughness Ra is 0.1 to 2 μm. Therefore, according to JIS B0633, in the case of Ra under the above condition (B2), it is standard that the cutoff value (reference length) is 0.8 mm.
However, not only the roughness component (high frequency component) but also the swell component (low frequency component) affects the tactile sensation during operation, outdoor anti-glare property, and resolution, so the cutoff value (reference length) When is set to 0.8 mm, the degree to which the undulation component (low frequency component) of the roughness curve is cut becomes large, and the operation is more susceptible to low frequencies than the outdoor antiglare and resolution. The tactile sensation may not be evaluated. Therefore, in the embodiment B, the cutoff value of the condition (B2) is set to 2.5 mm.

The condition (B2) is that the arithmetic mean roughness Ra _2.5 is 0.10 μm or more and 0.60 μm or less. When Ra _2.5 is less than 0.10 μm, light scattering is insufficient and the antiglare property is lowered. In addition, the contact area of the finger with the surface of the optical sheet increases, and the tactile sensation (slip sensation) deteriorates. When Ra _2.5 exceeds 0.60 μm, the smoothness during operation is impaired, and the contrast and resolution are deteriorated. From the viewpoint of tactile sensation during operation, outdoor antiglare property, and resolution, the condition (B2) preferably satisfies 0.15 μm ≤ Ra _2.5 ≤ 0.60 μm, and 0.25 μm ≤ Ra _2.5 . It is more preferable to satisfy ≤0.55 μm, and further preferably to satisfy 0.30 μm ≤Ra _2.5 ≤0.50 μm.
Further, when the arithmetic average roughness Ra _2.5 is 0.10 μm or more, the gradation-like color unevenness peculiar to the retardation value of the transparent substrate can be made less noticeable. The gradation-like color unevenness peculiar to the retardation value is the color unevenness of the rainbow pattern generated in the light passing through the transparent substrate having the retardation value, and such color unevenness is, for example, a polarizing plate or a predetermined color unevenness. It is observed when light that has passed through a transparent substrate having a retardation value is visually recognized through polarized sunglasses.
By satisfying the condition (B3) described later in addition to the above condition (B2), the above-mentioned condition (B1) can be more easily satisfied. In particular, when Ra _2.5 is preferably 0.25 μm or more, more preferably 0.30 μm or more, it is possible to make the gradation-like color unevenness less noticeable, for example, for a display element having a wide color gamut.

The unevenness is the ten-point average roughness (Rz _0.8 ) of JIS B0601: 1994 when the cutoff value is 0.8 mm, and JIS B0601: 1994 when the cutoff value is 2.5 mm. It is preferable that the ten-point average roughness (Rz _2.5 ) of the above satisfies the following condition (B3).
Rz _0.8 / (Rz _2.5 -Rz _0.8 ) ≤ 3.2 (B3)

When the cutoff value is 0.8 mm, the degree to which the low frequency component of the roughness curve is cut is larger than when the cutoff value is 2.5 mm. That is, the value of Rz _0.8 can be regarded as the high frequency component in the unevenness of the optical sheet, and the value of (Rz _2.5 -Rz _0.8 ) can be regarded as the low frequency component in the unevenness of the optical sheet. Therefore, the condition (B3) "Rz _0.8 / (Rz _2.5 -Rz _0.8 )" can be regarded as the ratio of the high frequency component to the low frequency component of the unevenness.

In the condition (B3), the fact that Rz _0.8 / (Rz _2.5 -Rz _0.8 ) is 3.2 or less means that there are not too many high frequency components and a certain amount of low frequency components are contained. Therefore, when a force is applied to the unevenness, the unevenness of the high frequency component is easily maintained, while the unevenness of the low frequency component is easily deformed, and the above-mentioned condition (B1) is more easily satisfied.
Even if the absolute amount of unevenness is increased, the condition (B1) can be easily satisfied, but in that case, the condition (B2) cannot be satisfied. In other words, it is preferable to satisfy the condition (B1) by satisfying the condition (B3) in the range of the unevenness satisfying the condition (B2).
The condition (B3) more preferably satisfies Rz _0.8 / (Rz _2.5 -Rz _0.8 ) ≤ 3.0, and Rz _0.8 / (Rz _2.5 -Rz _0.8 ) ≤ 3.0. It is more preferable to satisfy 2.9. Satisfying Rz _0.8 / (Rz _2.5 -Rz _0.8 ) ≤ 3.0 is for display elements with gradation-like color unevenness peculiar to the retardation value of the transparent substrate, for example, a display element having a wide color gamut. It also leads to being able to make it less noticeable. The lower limit of Rz _0.8 / (Rz _2.5 -Rz _0.8 ) is preferably 1.0 or more, more preferably 2.0 or more, and even more preferably 2.5 or more.

Further, it is preferable that the above-mentioned Rz _2.5 and the above-mentioned Ra _2.5 satisfy the following condition (B4).
5.7 ≤ Rz _2.5 / Ra _2.5 (B4)

The arithmetic mean roughness Ra is a value obtained as an even elevation by integrating the absolute values of the peaks and valleys of the roughness curve of the evaluation length and dividing by the evaluation length. On the other hand, the ten-point average roughness Rz is a roughness curve having an evaluation length of N times the sampling length equal to the cutoff value divided into N equal parts, and the height from the first place to the fifth place for each section. It is the arithmetic mean value of N Rz'when the interval Rz'between the average elevation of the mountaintop and the average elevation of the valley bottom at the depths from the 1st to the 5th is calculated. That is, Ra is the average value of the elevations of the entire roughness curve, while Rz is the average of the elevations when focusing on the 5 points at the high points and the 5 points at the low points in the roughness curve. .. Therefore, when the roughness curve does not have randomness, Ra and Rz are substantially the same, but when the roughness curve has randomness, Rz is larger than Ra. Therefore, Rz / Ra is an index showing the randomness of the roughness curve.

When Rz _2.5 / Ra _2.5 is 5.7 or more, the randomness of the roughness curve is improved, the contact area of the finger with the optical sheet surface is reduced, and the tactile sensation is improved. Further, by improving the randomness of the roughness curve, there is a tendency that the color unevenness of the gradation tone can be made less noticeable for the display element having a wide color gamut. From the viewpoint of tactile sensation (slip sensation) and resolution, it is preferable that the roughness is not random more than necessary.
The condition (B4) more preferably satisfies 6.0 ≤ Rz _2.5 / Ra _2.5 ≤ 10.0, and satisfies 6.5 ≤ Rz _2.5 / Ra _2.5 ≤ 9.5. Is even more preferable, and it is even more preferable to satisfy 7.0 ≤ Rz _2.5 / Ra _2.5 ≤ 9.0.

The Rz _2.5 of the unevenness is preferably 0.50 to 4.30 μm, more preferably 1.00 to 4.00 μm, and further preferably 2.00 to 4.00 μm. When Rz _2.5 is 0.50 μm or more, it is easy to satisfy the above-mentioned condition (B1), it is possible to impart outdoor antiglare property to the touch panel, and the tactile sensation (slip sensation) is further improved. be able to. When Rz _2.5 is 4.30 μm or less, the occurrence of glare can be suppressed, and the smoothness during operation is not impaired.
When Rz _2.5 is 2.00 μm or more, it is possible to make the color unevenness of the gradation tone peculiar to the retardation value of the transparent substrate, for example, a display element having a wide color gamut less noticeable.

Further, for the unevenness, it is preferable that the local peak average interval (S _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (B5).
S _2.5 ≤ 70 μm (B5)

When the local average interval (S _2.5 ) is 70 μm or less, the contact area of the finger with the optical sheet surface is reduced and the tactile sensation (slip sensation) can be improved.
The condition (B5) is more preferably S _2.5 ≤ 65 μm, further preferably 20 μm ≤ S _2.5 ≤ 60 μm, and even more preferably 30 μm ≤ S _2.5 ≤ 55 μm.

Further, it is preferable that the maximum height (Ry _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following conditions for the unevenness.
0.60 μm ≤ Ry _2.5 ≤ 5.0 μm
When Ry _2.5 is 5.0 μm or less, it is possible to prevent finger catching during operation and improve operability. In addition, it is possible to further prevent the occurrence of glare. When Ry _2.5 is 0.60 μm or more, outdoor antiglare property can be imparted.
Further, Ry _2.5 is more preferably 1.0 μm or more and 4.7 μm or less, and 1.2 μm or more and 4.5 μm or less, from the viewpoint of facilitating the satisfaction of the conditions (B6) and (B7) described later. Is even more preferable.

Further, it is preferable that the above-mentioned (Ry _2.5 ) and the above-mentioned Rz _2.5 satisfy the following condition (B6).
Ry _2.5 / Rz _2.5 ≤ 1.5 (B6)
When Ry _2.5 / Rz _2.5 is 1.5 or less, it is possible to prevent finger catching during operation and improve operability. In addition, it is possible to further prevent the occurrence of glare, and it is possible to easily impart outdoor anti-glare properties.
Ry _2.5 / Rz _2.5 is more preferably 1.10 or more and 1.40 or less, and further preferably 1.18 or more and 1.37 or less.

Further, it is preferable that the average inclination angle (θa _2.5 ) of the unevenness when the cutoff value is 2.5 mm satisfies the following conditions for the unevenness.
1.0 ° ≤ θa _2.5 ≤ 5.5 °
When θa _2.5 is 1.0 ° or more, the touch panel can be provided with outdoor antiglare property and the operability can be improved. When θa is 5.5 ° or less, it is possible to suppress a decrease in contrast and achieve both outdoor anti-glare property and contrast. It is more preferable that θa _2.5 satisfies 1.3 ° ≤ θa _2.5 ≤ 4.5 °, and even more preferably 2.0 ° ≤ θa _2.5 ≤ 4.0 °. Further, when θa _2.5 is 1.3 ° or more, the gradation-like color unevenness peculiar to the retardation value of the transparent substrate can be made inconspicuous. Further, when it is preferably 1.5 ° or more, more preferably 2.0 ° or more, it is possible to make the gradation-like color unevenness less noticeable, for example, for a display element having a wide color gamut.
Here, the "average inclination angle θa" is a value defined in the instruction manual (revised 1995.07.20) of the surface roughness measuring instrument (trade name: SE-3400) manufactured by Kosaka Research Institute. , As shown in FIG. 3, the arctangent θa = tan ^-1 {(h ₁ + h ₂ + h) of the sum of the heights of the convex portions existing in the reference length L (h ₁ + h ₂ + h ₃ + ... + h _n ). ₃ + ... + h _n ) / L}.

［式（Ａ）中、「Ｌ」は基準長さを示し、「ｄｙ／ｄｘ」は、粗さ曲線の各単位区間の傾きを示す。］
なお、「基準長さ」とは「カットオフ値」を意味する。すなわち、カットオフ値が０．８ｍｍの場合は基準長さが０．８ｍｍである。また、単位測定区間とは、カットオフ値をサンプリング数で除した長さの区間である。サンプリング数は１５００とする。 Further, θa can be calculated from the following equation (A).

[In the formula (A), "L" indicates the reference length, and "dy / dx" indicates the slope of each unit interval of the roughness curve. ]
The "reference length" means a "cutoff value". That is, when the cutoff value is 0.8 mm, the reference length is 0.8 mm. The unit measurement section is a section having a length obtained by dividing the cutoff value by the number of samplings. The number of samplings is 1500.

Further, it is preferable that the above-mentioned (θa _2.5 ) and the above-mentioned Ry _2.5 / Rz _2.5 satisfy the following condition (B7).
0.8 ≤ θa _2.5 / (Ry _2.5 / Rz _2.5 ) ≤ 5.0 (B7)
When θa _2.5 / (Ry _2.5 / Rz _2.5 ) is within the above range, unevenness with appropriate randomness is obtained, and the antiglare property, resolution, operability, and retardation value of the transparent substrate are obtained. It is possible to improve the balance of being able to make the color unevenness of the gradation tone peculiar to the above inconspicuous.
θa _2.5 / (Ry _2.5 / Rz _2.5 ) is more preferably 1.0 or more and 4.5 or less, and even in the case of a display element having a wide color gamut, gradation-like color unevenness is conspicuous. Since it can be made difficult, it is more preferably 1.2 or more and 4.0 or less.

Further, for the unevenness, it is preferable that the average interval (Sm _2.5 ) of the unevenness of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following conditions.
Sm _2.5 ≤ 160 μm
When Sm _2.5 is 160 μm or less, the contact area of the finger with the surface of the optical sheet is reduced, and the tactile sensation (slip sensation) can be improved. Sm _2.5 is more preferably 150 μm or less, further preferably 145 μm or less. The lower limit is preferably 30 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more.
It should be noted that the smaller the Sm _2.5 , the more the occurrence of glare can be suppressed even in a high-definition display.

Examples of the method for forming the unevenness described above include physical or chemical treatment such as (x1) embossing, sandblasting, and etching, molding by (x2) mold, and formation of an uneven layer by (x3) coating. Among these methods, molding by the mold of (x2) is preferable from the viewpoint of reproducibility of the uneven shape, and formation of the uneven layer by the coating of (x3) is preferable from the viewpoint of productivity and compatibility with various types. be.

Molding with a mold can be performed by producing a mold having a shape complementary to the unevenness, pouring a material for forming the unevenness into the mold, and then removing the mold from the mold. Here, if a material constituting the unevenness is used as the material, the transparent base material is superposed after the material is poured into the mold, and the unevenness is taken out from the mold together with the transparent base material, an optical sheet having the unevenness on the transparent base material is obtained. Can be obtained. Further, if the material constituting the transparent base material is poured into the mold and then taken out from the mold, an optical sheet composed of a single layer of the transparent base material and having irregularities on the surface of the transparent base material can be obtained.
When a curable resin composition (thermosetting resin composition or ionizing radiation curable resin composition) is used as a material to be poured into a mold, it is preferable to cure the curable resin composition before removing it from the mold.
The formation of unevenness by the mold is preferable in that the unevenness shape is excellent in reproducibility.

To form the uneven layer by coating, a coating liquid for forming an uneven layer containing a resin component and particles is applied onto a transparent substrate by a known coating method such as gravure coating or bar coating, and dried as necessary. It can be formed by curing. In order for the concavo-convex layer to satisfy the above-mentioned conditions (B1) and (B2), it is preferable that the film thickness of the concavo-convex layer, the content of particles, and the average particle diameter of the particles are within the ranges described below.

The film thickness of the uneven layer is preferably 1.0 to 10 μm, more preferably 1.5 to 5 μm, and even more preferably 1.8 to 4 μm. The thickness of the uneven layer is determined by measuring the thickness at 20 points from a cross-sectional image taken with, for example, a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), and from the average value of the values at the 20 points. Can be calculated. The acceleration voltage of TEM or STEM is preferably 1 to 5 kV, and the magnification is preferably 1000 to 10,000 times.

As the particles, either organic particles or inorganic particles can be used as long as they can form irregularities. Examples of the organic particles include particles made of polymethylmethacrylate, polyacrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluororesin, polyester resin and the like. Can be mentioned. Examples of the inorganic particles include particles made of silica, alumina, zirconia, titania and the like. Among these particles, translucent organic particles and silica particles are preferable from the viewpoint of ease of dispersion control.
The above particles can be used alone or in combination of two or more having different materials and particle sizes.

Further, the particles are preferably aggregates. When the uneven layer contains agglomerates of particles, the unevenness of the high frequency component is easily maintained when a force is applied to the uneven layer, while the unevenness of the low frequency component is easily deformed, and the above condition (B1) is satisfied. It will be easier to fill.
Further, in order to make the gradation-like color unevenness less noticeable even in a display element having a wide color gamut, the particles are preferably irregular particles having a particle diameter equal to or larger than the wavelength of visible light. Since the uneven layer contains amorphous particles, it is possible to suppress gradation-like color unevenness.

The content of the particles is preferably 4 to 25% by mass, more preferably 5 to 20% by mass, and even more preferably 5 to 15% by mass in the total solid content forming the uneven layer. ..

The average particle size of the particles in the concavo-convex layer varies depending on the thickness of the concavo-convex layer and cannot be unequivocally determined. It is preferably 1.0 to 6.0 μm, more preferably 1.0 to 5.0 μm. When the particles are agglomerated, it is preferable that the average particle size of the agglomerated particles satisfies the above range.

The average particle diameter of the particles can be calculated by the following operations (y1) to (y3).
(Y1) Select the particles that can be seen most in the observation screen from the image of the cross section taken by using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The acceleration voltage of TEM or STEM is preferably 1 to 30 kV, and the magnification is preferably 5000 to 300,000 times.
(Y2) Particles having the maximum diameter are extracted from the observation image, and the particle diameter of each particle is calculated. The particle size is measured as the distance between straight lines in a combination of two straight lines such that the distance between the two straight lines is maximized when the cross section of the particle is sandwiched between two arbitrary parallel straight lines.
(Y3) The same operation is performed on the observation image on another screen of the same sample, and the value obtained from the number average of the particle diameters for a total of 20 particles is taken as the average particle diameter of the particles.
In the case of agglomerated particles, the maximum diameter portion of the agglomerated agglomerates is regarded as the particle diameter.

From the viewpoint of facilitating the uneven layer from satisfying the above-mentioned conditions (B1) and (B2), the film thickness of the uneven layer is preferably larger than the average particle diameter of the particles. More specifically, the ratio of [average particle size of particles] / [thickness of uneven layer] is preferably 0.20 to 0.99, and preferably 0.50 to 0.90. More preferred.
Even if the particles have a wide particle size distribution (a single particle having a wide particle size distribution, or a mixed particle having two or more types of particles having different particle size distributions having a wide particle size distribution). However, from the viewpoint of suppressing glare, it is preferable that the particle size distribution is narrow.

The resin component of the uneven layer preferably contains a thermosetting resin composition or an ionized radiation curable resin composition, and more preferably contains an ionized radiation curable resin composition from the viewpoint of improving mechanical strength. Among them, it is more preferable to contain 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 cured by heating.
Examples of the thermosetting resin include acrylic resin, urethane resin, phenol resin, urea melamine resin, epoxy resin, unsaturated polyester resin, silicone resin and the like. To the thermosetting resin composition, a curing agent is added to these curable resins as needed.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter, also referred to as “ionizing radiation curable compound”). Examples of the ionizing radiation curable functional group include an ethylenically unsaturated bond group such as a (meth) acryloyl group, a vinyl group and an allyl group, an epoxy group and an oxetanyl group. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferable, a compound having two or more ethylenically unsaturated bond groups is more preferable, and a compound having two or more ethylenically unsaturated bond groups is particularly preferable. Polyfunctional (meth) acrylate compounds are more preferred. As the polyfunctional (meth) acrylate compound, either a monomer or an oligomer can be used.
The ionizing radiation means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking a molecule, and usually, an ultraviolet ray (UV) or an electron beam (EB) is used. Electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion rays can also be used.

Among the polyfunctional (meth) acrylate compounds, the bifunctional (meth) acrylate monomers include ethylene glycol di (meth) acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexane. Didiol diacrylate, dicyclopentenyl di (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol di (meth) acrylate, tricyclodecanediyl dimethylene di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di ( Meta) Acrylate and the like can be mentioned.
Examples of the trifunctional or higher functional (meth) acrylate-based monomer include trimethylol propanetri (meth) acrylate, trimethylol ethanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and penta. Elythritol hexa (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, ditrimethylol propanetetra (meth) Examples thereof include acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate and the like.
Further, the (meth) acrylate-based monomer may be one in which a part of the molecular skeleton is modified, and is modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol and the like. Can also be used.

Examples of the polyfunctional (meth) acrylate-based oligomer include acrylate-based polymers such as urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and polyether (meth) acrylate.
Urethane (meth) acrylates are obtained, for example, by reacting polyhydric alcohols and organic diisocyanates with hydroxy (meth) acrylates.
Further, the preferable epoxy (meth) acrylate is a (meth) acrylate obtained by reacting a (meth) acrylic acid with a trifunctional or higher functional aromatic epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin and the like, and a bifunctional one. (Meta) acrylate obtained by reacting the above aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. with polybasic acid and (meth) acrylic acid, and bifunctional or higher functional aromatic epoxy resin, It is a (meth) acrylate obtained by reacting an alicyclic epoxy resin, an aliphatic epoxy resin or the like with phenols and (meth) acrylic acid.
The ionizing radiation curable compound may be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains an additive such as a photopolymerization initiator or a photopolymerization accelerator.
Examples of the photopolymerization initiator include acetophenone, benzophenone, α-hydroxyalkylphenone, α-aminoalkylphenone, α-hydroxyketone, Michler ketone, benzoin, benzylmethyl ketal, benzoyl benzoate, α-acyl oxime ester, and acylphosphine oxides. , One or more selected from thioxanthones and the like.
Among the above photopolymerization initiators, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone, 2-Hydroxy-2-methyl-1-phenyl-propane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1- It is preferable to select one or more types of ON as appropriate.

The photopolymerization initiator is not limited to the above compounds, and may be any photopolymerization initiator as long as it has the ability to initiate polymerization by ultraviolet rays. These photopolymerization initiators can be used alone or in combination of two or more.
The content of the photopolymerization initiator in the ionizing radiation curable resin composition is not particularly limited, but it is preferably used within the range of 1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the ultraviolet curable compound. Even when a plurality of types are used, it is preferable to use each within the above range.

The photopolymerization initiator preferably has a melting point of 100 ° C. or higher. By setting the melting point of the photopolymerization initiator to 100 ° C. or higher, the photopolymerization initiator remaining during the formation of the transparent conductive film of the touch panel or the heat of the crystallization step is sublimated, and the low resistance of the transparent conductive film is impaired. Can be prevented.
Further, the photopolymerization accelerator can reduce the polymerization inhibition due to air at the time of curing and accelerate the curing rate. For example, from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester and the like. One or more selected species can be mentioned.

Further, it is preferable that the uneven layer forming coating liquid contains a leveling agent. Examples of the leveling agent include a fluorine-based leveling agent, a silicone-based leveling agent, a fluorine-silicone copolymerization-based leveling agent, and the like. Above all, a silicone-based leveling agent is preferably used from the viewpoint of making it easier for the uneven layer to satisfy the above-mentioned conditions (B1) and (B2). Further, the non-reactive type tends to have better touch panel operability than the reactive type.
The amount of the leveling agent added is preferably 0.01 to 5.0% by weight based on the total solid content of the uneven layer.

It is preferable that the unevenness of the optical sheet is treated with antifouling treatment. By applying the antifouling treatment, it is possible to prevent the unevenness from accumulating dirt and impairing the surface shape of the embodiment B. Further, the antifouling treatment with a fluorine-based mold release agent, a silicone-based mold release agent, or the like is preferable in that it imparts slipperiness to the unevenness, makes it easier to satisfy the above-mentioned condition (B1), and improves operability. ..
As means for antifouling treatment, a means for incorporating a mold release agent such as a fluorine-based mold release agent and a silicone-based mold release agent into the uneven layer, and a means for forming a mold release layer on the outermost surface of the optical sheet with the above-mentioned mold release agent. Can be mentioned. When the release agent is contained in the uneven layer, the content of the release agent is preferably 0.5 to 5.0% by mass of the total solid content of the uneven layer.

(Transparent base material)
The transparent substrate used for the optical sheet is preferably one having light transmittance, smoothness, heat resistance, and excellent mechanical strength. Examples of such a transparent base material include polyester, triacetyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulphon, polysulphon, polypropylene, polymethylpentene, polyvinyl chloride, and polyvinyl acetal. , Polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane and plastic films such as amorphous olefin (Cyclo-Olefin-Polymer: COP). The transparent base material may be made by laminating two or more plastic films.
In addition to the above-mentioned plastic films manufactured by general-purpose methods such as melt extrusion molding method: extension molding (inflation method, T-die method), solution casting method: solution casting, and calendering method: calendering, the film has releasability. It may be a film produced by forming a coating film made of a resin such as an ionizing radiation curable resin composition on a substrate and peeling the coating film from the substrate.

Among the above, from the viewpoint of mechanical strength and dimensional stability, stretch-processed, particularly biaxially-stretched polyester (polyethylene terephthalate, polyethylene naphthalate) is preferable. Further, COP and polyester are suitable because they have excellent weather resistance.

The thickness of the transparent substrate is preferably 5 to 300 μm, more preferably 10 to 200 μm, and even more preferably 20 to 130 μm.
In addition to physical treatment such as corona discharge treatment and oxidation treatment, a paint called an anchor agent or a primer may be applied to the surface of the transparent base material in advance in order to improve the adhesiveness.

The transparent substrate preferably has a retardation value of more than 0 nm and less than 3,000 nm, and more preferably more than 20 nm and 2,000 nm or less. The retardation value is a value at a wavelength of 550 nm.
The retardation value of the transparent substrate is the refractive index n _x in the slow-phase axial direction, which is the direction in which the refractive index is the largest in the plane of the transparent substrate, and the direction orthogonal to the slow-phase axial direction in the plane of the transparent substrate. It is expressed by the following equation by the refractive index _ny in the phase-advancing axis direction and the thickness d of the transparent substrate.
Restriction value (Re) = (n _x − n _y ) × d
The retardation value can be measured by, for example, the trade names "KOBRA-WR" and "PAM-UHR100" manufactured by Oji Measuring Instruments Co., Ltd.

Normally, when a transparent substrate having a small retardation value is used, gradation-like color unevenness caused by light passing through the transparent substrate is observed (for example, passing through a polarizing plate or a transparent substrate having a predetermined retardation value). It is observed when the emitted light is visually recognized through polarized sunglasses.) However, since the optical sheet used in the touch panel of the embodiment B satisfies the condition (B2), even if a transparent base material having a small retardation value is used, the color unevenness of the gradation tone can be made less noticeable.
It should be noted that the fact that the gradation-like color unevenness can be made inconspicuous even if the retardation value is reduced leads to the fact that the thickness of the transparent base material can be reduced. That is, a transparent base material that produces retardation (for example, a polyester film that is a general-purpose base material) is usually uniaxially stretched to increase the thickness of the base material to increase the retardation value to create a gradation tone. It suppresses the occurrence of color unevenness. However, in the optical sheet used in the touch panel of the embodiment B, even if the thickness of the transparent base material (for example, a polyester film which is a general-purpose base material) is reduced, the gradation-like color unevenness can be made less noticeable.
Furthermore, the fact that the gradation-like color unevenness can be made less noticeable even if the retardation value is reduced is that a plastic film (polyimide film, aramid film) that is out of the selection because it is usually prone to gradation-like color unevenness can be used. Leads to. Polyimide film and aramid film are preferable because they have excellent bending resistance.
In recent years, the color gamut of display elements has tended to expand. A display element with a wide color gamut has a sharp spectral spectrum for each color (R, G, B), and in such a display element, gradation-like color unevenness peculiar to the retardation value is particularly conspicuous. It tends to be easy. The optical sheet used in the touch panel of the embodiment B is preferable in that the gradation-like color unevenness can be made inconspicuous even for a display element having a wide color gamut.

The optical sheet may have a functional layer such as an antireflection layer, an antifouling layer, and an antistatic layer on the uneven surface and / or on the surface opposite to the unevenness. Further, in the case of a configuration having an uneven layer on the transparent base material, a functional layer may be provided between the transparent base material and the uneven layer in addition to the above-mentioned portion.
When another functional layer is laminated on the uneven layer, the unevenness on the outermost surface satisfies the range of the present application. The unevenness may be a single layer or a plurality of layers as long as the outermost surface is within the range of the present application.

The touch panel of the embodiment B is provided with outdoor anti-glare property due to the uneven shape of the optical sheet described above, and has excellent operability. In addition, it is possible to suppress a decrease in resolution.
Therefore, it is preferable that the touch panel of the embodiment B is installed on the exit surface side of the display device of an in-vehicle display device and the display element of a smartphone or tablet (multifunctional mobile terminal) carried when moving such as a train.

[Display device]
The display device of the embodiment B has irregularities on the outermost surface of the display element on the exit surface side, and the irregularities satisfy the above-mentioned conditions (B1) and (B2).
As the display device of the embodiment B, the same optical sheet as the optical sheet used for the touch panel of the above-described embodiment B can be used as the member having the unevenness on the outermost surface.

Examples of the display element include a liquid crystal display element, an in-cell touch panel liquid crystal display element, an EL display element, a plasma display element, and the like. The liquid crystal display element has a backlight on the back surface of the liquid crystal element.
The in-cell touch panel liquid crystal element incorporates touch panel functions such as a resistance film type, a capacitance type, and an optical type inside a liquid crystal element having a liquid crystal sandwiched between two glass substrates. Examples of the liquid crystal display method of the in-cell touch panel liquid crystal element include an IPS method, a VA method, a multi-domain method, an OCB method, an STN method, and a TSTN method. The in-cell touch panel liquid crystal element is described in, for example, Japanese Patent Application Laid-Open No. 2011-76602 and Japanese Patent Application Laid-Open No. 2011-222009.

The optical sheet can be installed on the exit surface side of the display element in the following order, for example.
(A) Display element / surface protection plate / optical sheet (b) Display element / optical sheet (c) In the case of touch panels (a) and (b) having a display element / optical sheet at the top, the unevenness of the optical sheet is displayed. By arranging the display device so as to face the opposite side of the element, it is possible to impart outdoor antiglare property to the display device. In addition, it is possible to suppress a decrease in the resolution of the display element, and further, it is possible to make it difficult to see scratches on the surface or the display element.
In the case of (c), the display device is a display device with a touch panel provided with a touch panel having an optical sheet at the uppermost portion on the exit surface side of the display element. In this case, the display device can be a display device having excellent operability of the touch panel as well as outdoor anti-glare property and high resolution.
Therefore, the display device of the embodiment B is suitable as an in-vehicle display device and a smartphone or tablet (multifunctional mobile terminal) to be carried when moving such as a train.

As described above, the optical sheet used in the display device of the B embodiment can make the gradation-like color unevenness less noticeable even for a display element having a wide color gamut. Examples of the standard representing the color gamut include "ITU-R Recommendation BT.2020 (hereinafter referred to as" BT.2020 ")" and the like. ITU-R is an abbreviation for "International Telecommunication Union-Radiocommunication Sector" and is an abbreviation for ITU-R Recommendation BT. 2020 is an international standard for the color gamut of Super Hi-Vision.
The display device of the embodiment B is a BT. Even for a display element having a coverage rate of 60% or more in 2020, color unevenness in gradation tone can be made inconspicuous.
<BT. Formula for 2020 coverage>
[Of the area of the CIE-xy chromaticity diagram of the display element, BT. Area overlapping with the area of the 2020 CIE-xy chromaticity diagram / BT. Area of CIE-xy chromaticity diagram of 2020] x 100 (%)

In addition, BT. The "area of the CIE-xy chromaticity diagram" required when calculating the coverage rate of 2020 is the CIE-Yxy color in the red (R) display, the green (G) display, and the blue (B) display. The x and y values of the system are measured, respectively, and calculated from the "red (R) vertex coordinates", "green (G) vertex coordinates", and "blue (B) vertex coordinates" obtained from the measurement results. can. The x-value and y-value of the CIE-Yxy color system can be measured by, for example, a spectral radiance meter CS-2000 manufactured by Konica Minolta.
Display elements with a wide color gamut include three-color independent organic EL display devices (among them, three-color independent organic EL elements with a microcavity structure), and liquid crystal display elements that use quantum dots for the backlight. Examples thereof include a liquid crystal display element using a three-wavelength white LED (a combination of a near-ultraviolet LED and a blue phosphor, a green phosphor, and a red phosphor) as a backlight.

[Optical sheet]
The optical sheet of the embodiment B has irregularities on one surface, and the irregularities satisfy the above-mentioned conditions (B1) and (B2). In the optical sheet of the embodiment B, when another functional layer is laminated on the unevenness, the unevenness on the outermost surface satisfies the range of the present application. The unevenness may be a single layer or a plurality of layers as long as the outermost surface is within the range of the present application.
Examples of the optical sheet of the embodiment B include the same optical sheets used for the touch panel of the above-described embodiment B.

When the optical sheet of the embodiment B is used for the touch panel, the optical sheet is installed so that the surface having irregularities is the surface on the operator side of the touch panel.
In order to satisfy the above-mentioned conditions (B1) and (B2), the optical sheet of the embodiment B is provided at the uppermost part of the touch panel to impart outdoor antiglare property to the touch panel and to operate the touch panel. Can be made excellent.
Therefore, the optical sheet of the embodiment B can be preferably used on the surface of an in-vehicle display device, the surface of a smartphone or tablet (multifunctional mobile terminal) carried when moving such as a train.

[Method of selecting optical sheets]
In the method for selecting an optical sheet according to the embodiment B, an optical sheet having irregularities on one surface and the irregularities satisfy the above-mentioned conditions (B1) and (B2) is used as an optical sheet located at the top of the touch panel. It is to be selected.

In the method for selecting an optical sheet according to the embodiment B, an optical sheet having good operability, outdoor antiglare property, and high resolution can be selected without performing an operability test of the optical sheet. , Product design of optical sheets and quality control can be performed efficiently.

The above-mentioned conditions (B1) and (B2) are indispensable conditions for the determination condition for selecting the optical sheet of the touch panel. The determination condition of the condition (B1) is, for example, that the ratio (μs / μk) when the load is 50 to 150 g is preferably in the range of 1.6 to 2.5, and more preferably 1.7 to 2.2. Is within the range of. The ratio (μs / μk) when the load is 900 to 1100 g is preferably in the range of 1.0 to 1.5, and more preferably in the range of 1.1 to 1.4. Further, the determination condition of the condition (B2) preferably satisfies 0.15 μm ≤ Ra _2.5 ≤ 0.60 μm, more preferably 0.25 μm ≤ Ra _2.5 ≤ 0.55 μm, and 0. It is more preferable to satisfy 30 μm ≤ Ra _2.5 ≤ 0.50 μm.

In the method for selecting the optical sheet of the touch panel, it is more preferable to set the following condition (B3) as an additional determination condition from the viewpoint of excellent operability and outdoor antiglare property.
Rz _0.8 / (Rz _2.5 -Rz _0.8 ) ≤ 3.2 (B3)
The determination condition of the condition (B3) is preferably in a suitable numerical range of the optical sheet of the above-mentioned embodiment B.
Further, it is preferable to set other parameters as additional determination conditions.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the embodiments described in the Examples. In addition, "part" and "%" are based on mass unless otherwise specified.

<Example of Embodiment A>
A1. Measurement and Evaluation The following measurements and evaluations were performed on the optical sheets produced in Examples and Comparative Examples. The results are shown in Table 1.

A1-1. Static friction coefficient Using HEIDON HHS2000 manufactured by Shinto Kagaku Co., Ltd., the static friction coefficient was measured by the following method in the constant load reciprocating friction measurement mode.
A scratching needle made of sapphire with a tip radius of 0.3 mm was vertically brought into contact with the unevenness of the optical sheet, and while applying a vertical load of 100 g to the scratching needle, a one-way length of 10 mm was reciprocated at a scanning speed of 10 mm / sec. The static friction coefficient (μs ₁₀ ) applied to the scratch needle was measured. In addition, the static friction coefficient (μs ₂₀ ) was measured when the scanning speed was 20 mm / sec.
The atmosphere at the time of measurement was 23 ° C. ± 5 ° C. and 50% ± 10% humidity. Further, before the start of measurement, each sample was left in an atmosphere of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10% for 10 minutes or more.

A1-2. Surface roughness measurement (cutoff value 2.5 mm)
The optical sheets of Examples and Comparative Examples were cut into 10 cm squares. The cutting points were selected from random parts after visually confirming that there were no abnormal points such as dust and scratches. The cut surface member is passed through an optical transparent adhesive sheet (refractive index: 1.47, thickness 100 μm) manufactured by Toray Industries, Inc., and a black plate measuring 10 cm in length × 10 cm in width (manufactured by Kuraray Industries, Inc., product name: COMO Glass Part No .: Twenty samples each of DFA502K (thickness 2.0 mm) bonded together were prepared.
Using a surface roughness measuring instrument (model number: SE-3400 / manufactured by Kosaka Laboratory Co., Ltd.), set the sample so that it is fixed and in close contact with the measurement stage, and then the unevenness of the optical sheet is determined according to the following measurement conditions. Ra, Rz, S, and Sm of JIS B0601: 1994 of the surface were measured. The calculation of θa shall be in accordance with the instruction manual (revised 1995.07.20) of the surface roughness measuring instrument (SE-3400) manufactured by Kosaka Research Institute. The average value of the 20 samples was Ra, Rz, S, Sm and θa of each Example and Comparative Example. The atmosphere at the time of measurement was a temperature of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10%. Further, before the start of measurement, each sample was left in an atmosphere of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10% for 10 minutes or more.
[Needle of surface roughness detector]
Product name SE2555N manufactured by Kosaka Research Institute (tip radius of curvature: 2 μm, apex angle: 90 degrees, material: diamond)
[Measurement conditions of surface roughness measuring instrument]
-Reference length (cutoff value of roughness curve λc): 2.5 mm
・ Evaluation length (reference length (cutoff value λc) x 5): 12.5 mm
・ Feed speed of stylus: 0.5 mm / s
・ Vertical magnification: 2000 times ・ Horizontal magnification: 10 times ・ Skid: Not used (no contact with the measurement surface)
・ Cut-off filter type: Gaussian ・ Insensitive zone level: 10%
・ Tp / PC curve: Normal

A1-3. Surface roughness measurement (cutoff value 0.8 mm)
Using a surface roughness measuring instrument (model number: SE-3400 / manufactured by Kosaka Research Institute), the Rz of JIS B0601: 1994 on the uneven surface of the above 20 samples was measured under the following measurement conditions. The average value of 20 samples was taken as Rz of each Example and Comparative Example.
[Needle of surface roughness detector]
Product name SE2555N manufactured by Kosaka Research Institute (tip radius of curvature: 2 μm, apex angle: 90 degrees, material: diamond)
[Measurement conditions of surface roughness measuring instrument]
-Reference length (cutoff value of roughness curve λc): 0.8 mm
-Evaluation length (reference length (cutoff value λc) x 5): 4.0 mm
・ Feeding speed of stylus: 0.5 mm / s
・ Vertical magnification: 2000 times ・ Horizontal magnification: 10 times ・ Skid: Not used (no contact with the measurement surface)
・ Cut-off filter type: Gaussian ・ Insensitive zone level: 10%
・ Tp / PC curve: Normal

A1-4. Outdoor anti-glare A black acrylic plate was attached to the base material side of the obtained optical sheet via a transparent adhesive to prepare a sample for evaluation. Next, in an environment with an illuminance of 7,000 to 13,000 lux (environment near a window in fine weather), each evaluation sample was placed horizontally on a horizontal table with a height of about 1 m, and 20 people visually watched it from about 50 cm above at various angles. The evaluation was performed according to the following criteria, and the largest number of evaluations were used as the result.
A: I do not feel the glare of sunlight on the surface of the sample.
B: Depending on the angle, some glare of sunlight may be felt on the sample surface, but it is within the permissible range.
C: I strongly feel the glare of sunlight on the surface of the sample.

A1-5. Resolution The base material side of the obtained optical sheet is attached to the glass on the outermost surface of a commercially available mobile (7.9-inch LCD) via a transparent adhesive, and the illuminance is 7,000 to 13,000 lux (near a window in fine weather). In, each display device was horizontally installed on a horizontal table with a height of about 1 m, and 20 people visually confirmed the icons and characters on the initial screen of each display device from about 30 cm above at various angles. 2 points for icons and characters that can be recognized well, 1 point for icons and characters that can be recognized within the range that does not interfere with operation, and 0 points for icons and characters that are difficult to recognize and interfere with operation. went. The average score of 20 people was 1.6 points or more as A, 1.2 points or more and less than 1.6 points as B, and those with an average score of less than 1.2 points as C.

A1-6. Tactile (slippery)
A 10 cm square acrylic plate was attached to the base material side of the obtained optical sheet. Next, the following two types of operations, which are considered to be operated on the touch panel, were performed.
Twenty people performed the operation and evaluated it with 2 points for extremely good tactile sensation, 1 point for good tactile sensation, and 0 point for bad tactile sensation. The average score of 20 people was 1.6 points or more as A, 1.2 points or more and less than 1.6 points as B, and those with an average score of less than 1.2 points as C.
<Operation 1 (scroll operation)>
Operate with the pad of the index finger. I pressed the board with my dominant hand and moved the uneven surface of the optical sheet to the left and right in about 1 second with the pad of my non-dominant finger at a distance of about 5 cm. This was repeated 5 round trips.
<Operation 2 (enlargement / reduction operation)>
Hold the board with your dominant hand, place the non-dominant index finger and the side of your thumb approximately in the center of the uneven surface of the optical sheet, and move your index finger and thumb at the same time by 2 to 3 cm in about 1 second to operate when enlarging. .. Immediately after that, the operation for reduction to the original center was performed. This was repeated 5 round trips.

A1-7. Feeling of finger catching at the start of operation A sample similar to the above (A1-6) was prepared, and 20 people performed the operations 1 and 2 above. In Operation 1 and Operation 2, those with the same degree of finger catching were evaluated as 2 points, those with slightly different finger catching degrees were evaluated as 1 point, and those with different finger catching degrees were evaluated as 0 points. Those with an average score of 1.6 points or more for 20 people were designated as A, those with an average score of 1.2 points or more and less than 1.6 points were designated as B, and those with an average score of less than 1.2 points were designated as C.

A2. Fabrication of Optical Sheet [Example A1]
On a plastic film (thickness 80 μm triacetyl cellulose resin film (TAC), manufactured by Fujifilm, TD80UL), the uneven layer coating liquid A1 of the following formulation is applied, dried at 70 ° C. and a wind speed of 5 m / s for 30 seconds, and then dried. An optical sheet was obtained by irradiating ultraviolet rays in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the integrated light amount was 100 mJ / cm ² to form an uneven layer. The film thickness of the uneven layer was 7 μm.

<Concave and convex layer coating liquid A1>
55 parts of ditrimethylolpropane tetraacrylate (manufactured by SARTOMER, SR355)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone leveling agent 0.25 parts (manufactured by Momentive Performance Materials, TSF4460)
・ 10 parts of spherical polyacrylic-styrene copolymer particles (average particle diameter 6 μm, refractive index 1.52)
・ Colloidal silica fine particles (reactive hydrophobic treatment) 100 parts (manufactured by Nissan Chemical Industry Co., Ltd., solvent MIBK, solid content 30%) (average particle diameter 10 to 15 nm)
・ Solvent (MIBK) 110 copies

[Example A2]
An optical sheet was obtained in the same manner as in Example A1 except that the uneven layer coating liquid A1 of Example A1 was changed to the uneven layer coating liquid A2 of the following formulation and the film thickness was 6 μm.
<Concave and convex layer coating liquid A2>
60 parts of polyfunctional acrylate oligomer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., UV7640B, number of functional groups 6 to 7)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyester-modified polydimethylsiloxane (BYK-CHEMIE, BYK370)
16 parts of spherical polyacrylic-styrene copolymer particles (average particle diameter 3.5 μm, refractive index 1.52)
・ Fumed silica fine particles (hydrophobic treatment: octylsilane treatment) 6 parts (manufactured by Nippon Aerosil Co., Ltd., average particle diameter 10 to 15 nm)
・ Solvent 1 (toluene) 135 parts

[Example A3]
An optical sheet was obtained in the same manner as in Example A1 except that the concavo-convex layer coating liquid A1 of Example A1 was changed to the concavo-convex layer coating liquid A3 of the following formulation and the film thickness of the concavo-convex layer was 2.5 μm.
<Concave and convex layer coating liquid A3>
・ Pentaerythritol triacrylate 100 parts (manufactured by Nippon Kayaku Co., Ltd., KAYARAD-PET-30)
・ 14 parts of inorganic particles (atypical silica manufactured by Fuji Silysia Chemical Ltd.)
(Hydrophobic treatment, silane coupling agent, average aggregate particle diameter 2 μm)
-Photopolymerization initiator 5 parts (BASF, Irgacure 184)
-Silicone leveling agent 0.2 parts (TSF4460 manufactured by Momentive Performance Materials)
・ Release agent 2 parts (manufactured by Daikin Industries, Ltd., Optool DAC)
・ Solvent 1 (toluene) 150 parts ・ Solvent 2 (MIBK) 35 parts

[Comparative Example A1]
An optical sheet was obtained in the same manner as in Example A1 except that the concavo-convex layer coating liquid A1 of Example A1 was changed to the concavo-convex layer coating liquid A4 of the following formulation and the film thickness of the concavo-convex layer was 4 μm.
<Concave and convex layer coating liquid A4>
100 parts of aliphatic polyester skeleton hexafunctional urethane acrylate (manufactured by SARTOMER, CN968)
-Spherical polyacrylic-styrene copolymer particles 3 parts (average particle diameter 2.5 μm, refractive index 1.52)
・ Fumed silica fine particles (hydrophobic treatment: methyl) 3 parts (manufactured by Nippon Aerosil Co., Ltd., average particle diameter 10 to 15 nm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyether-modified polysiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., KF6004)
・ Solvent 1 (toluene) 150 parts ・ Solvent 2 (MIBK) 35 parts

[Comparative Example A2]
An optical sheet was obtained in the same manner as in Example A1 except that the uneven layer coating liquid A1 of Example A1 was changed to the uneven layer coating liquid A5 of the following formulation and the film thickness of the uneven layer was set to 3 μm.
<Concave and convex layer coating liquid A5>
100 parts of aliphatic polyester skeleton hexafunctional urethane acrylate (manufactured by SARTOMER, CN968)
15 parts of amorphous silica fine particles (hydrophobic treatment: silane coupling agent) (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 2.5 μm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyether-modified polysiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., X-22-2516)
・ Solvent (toluene) 150 parts

From the results in Table 1, it can be seen that the optical sheets of Examples A1 to A3 can impart outdoor antiglare property and can improve resolution and operability.

A3. Fabrication of Touch Panel An ITO conductive film having a thickness of 20 nm was formed on the transparent substrate side of the optical sheets of Examples A1 to A3 and Comparative Examples A1 and A2 by a sputtering method to form an upper electrode plate. Next, an ITO conductive film having a thickness of about 20 nm was formed on one surface of a tempered glass plate having a thickness of 1 mm by a sputtering method to form a lower electrode plate. Next, an ionizing radiation curable resin (Dot Cure TR5903: Taiyo Ink Co., Ltd.) was printed in dots on the surface of the lower electrode plate having the conductive film as a coating liquid for spacers by a screen printing method, and then ultraviolet rays were emitted with a high-pressure mercury lamp. After irradiation, spacers having a diameter of 50 μm and a height of 8 μm were arranged at intervals of 1 mm.
Next, the upper electrode plate and the lower electrode plate are arranged so that the conductive films face each other, and the edges are bonded with a double-sided adhesive tape having a thickness of 30 μm and a width of 3 mm. The resistance film type touch panel was manufactured.
The resistance film type touch panels of Examples A1 to A3 had outdoor antiglare properties, and had good resolution and operability. On the other hand, the resistance film type touch panel of Comparative Example A1 was dazzling due to insufficient outdoor antiglare property, and the operability was deteriorated. Further, the resistance film type touch panel of Comparative Example A2 could not recognize the image and character information on the display screen because the outdoor antiglare property was excessive.

A4. Fabrication of Display Device (1) The optical sheets of Examples A1 to A3 and Comparative Examples A1 and A2 and the surface glass plate of a commercially available ultra-high-definition liquid crystal display device (4.7 inches, pixel density of about 320 ppi) are transparent. The display devices (1) of Examples A1 to A3 and Comparative Examples A1 and A2 were manufactured by laminating with a pressure-sensitive adhesive. At the time of bonding, the uneven surface of the optical sheet was made to face the side opposite to the display element.
When the presence or absence of glare in the obtained display device (1) was visually evaluated, the glare was suppressed in the display devices (1) of Examples A1 to A3, the transfer of external light was small, and the visibility was good. there were. In addition, the display devices (1) of Examples A1 to A3 did not impair the resolution of the ultra-high-definition video.

A5. Preparation of Display Device (2) Examples A1 to A3 and Examples A1 to A3 and Comparative Examples A1 to A3 and Comparative Examples A1 to A3 and Comparative Examples A1 to A3 and Comparative Examples A1 to A3 except that the base material of the optical sheet was changed to a polyethylene terephthalate film (retamination value of 2,500 nm) having a thickness of 50 μm. Optical sheets of Examples A4 to A6 and Comparative Examples A3 and A4 were produced in the same manner as in Comparative Examples A1 and A2. The physical property values in Table 1 of the optical sheets of Examples A4 to A6 and Comparative Examples A3 and A4 are substantially the same as those of Examples A1 to A3 and Comparative Examples A1 and A2.
Commercially available organic EL display device (CIE-xy chromaticity diagram) having an optical sheet of Examples A4 to A6 and Comparative Examples A3 and A4 and a polarizing element on a three-color independent organic EL display element having a microcavity structure. The surface glass plate of BT.2020 (coverage rate of 77%) based on the above was bonded to each other via a transparent adhesive to prepare display devices (2) of Examples A4 to A6 and Comparative Examples A3 and A4. At the time of bonding, the uneven surface of the optical sheet was made to face the side opposite to the display element.

[Evaluation of display device (2)]
<Gradient color unevenness>
The screen of the display device (2) is displayed in white or substantially white. The screen was visually observed from various angles through polarized sunglasses, and 20 people evaluated whether or not the color unevenness of the gradation tone could be visually recognized according to the following criteria, and the evaluation of the largest number was the result. The results are shown in Table 2.
A: Gradation-like color unevenness cannot be visually recognized.
B: Gradation-like color unevenness is slightly visible, but there is no problem with image quality.
C: Gradation-like color unevenness is clearly visible, which greatly hinders image quality.

The display element constituting the display device (2) has an extremely wide color gamut and tends to cause gradation-like color unevenness, but the display devices of Examples A4 to A6 make it difficult to visually recognize the gradation-like color unevenness. can. In particular, the display device of Example A6 has a large Ra and has an uneven shape having appropriate randomness, so that the color unevenness of the gradation tone cannot be visually recognized at all.

<Example of Embodiment B>
B1. Measurement and Evaluation The following measurements and evaluations were performed on the optical sheets produced in Examples and Comparative Examples. The results are shown in Table 3.

B1-1. Friction Coefficient Using the brand name HEIDON NHS2000 manufactured by Shinto Kagaku Co., Ltd., the static friction coefficient μs and the dynamic friction coefficient μk were measured by the following method in the constant load reciprocating friction measurement mode, and the ratio (μs / μk) was calculated.
A sapphire scratch needle with a tip radius of 0.3 mm was vertically brought into contact with the unevenness of the optical sheet, and while applying a vertical load of 100 g to the scratch needle, a one-way length of 10 mm was reciprocated at a scanning speed of 5 mm / sec. The dynamic friction coefficient μk applied to the scratch needle was measured. Further, the dynamic friction coefficient μk was measured when the vertical load applied to the scratch needle was 500 g and 1000 g by the same operation. Further, in the same manner as in the above operation, the static friction coefficient μs was measured when the vertical load applied to the scratch needle was 100 g, 500 g and 1000 g.
The atmosphere at the time of measurement was 23 ° C. ± 5 ° C. and 50% ± 10% humidity. Further, before the start of measurement, each sample was left in an atmosphere of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10% for 10 minutes or more.
The mathematical formulas of Examples B1, B2, and Comparative Example B4 shown in Table 3 are approximate linear straight lines calculated by the least squares method.

B1-2. Surface roughness measurement (cutoff value 2.5 mm)
The optical sheets of Examples and Comparative Examples were cut into 10 cm squares. The cutting points were selected from random parts after visually confirming that there were no abnormal points such as dust and scratches. The cut surface member is passed through an optical transparent adhesive sheet (refractive index: 1.47, thickness 100 μm) manufactured by Toray Industries, Inc., and a black plate measuring 10 cm in length × 10 cm in width (manufactured by Kuraray Industries, Inc., product name: COMO Glass Part No .: Twenty samples each of DFA502K (thickness 2.0 mm) bonded together were prepared.
Using a surface roughness measuring instrument (model number: SE-3400 / manufactured by Kosaka Laboratory Co., Ltd.), set the sample so that it is fixed and in close contact with the measurement stage, and then the unevenness of the optical sheet is determined according to the following measurement conditions. Ra, Rz, S, and Sm of JIS B0601: 1994 of the surface were measured. The calculation of θa shall be in accordance with the instruction manual (revised 1995.07.20) of the surface roughness measuring instrument (SE-3400) manufactured by Kosaka Research Institute. The average value of the 20 samples was Ra, Rz, S, Sm and θa of each Example and Comparative Example. The atmosphere at the time of measurement was a temperature of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10%. Further, before the start of measurement, each sample was left in an atmosphere of 23 ° C. ± 5 ° C. and a humidity of 50% ± 10% for 10 minutes or more.
[Needle of surface roughness detector]
Product name SE2555N manufactured by Kosaka Research Institute (tip radius of curvature: 2 μm, apex angle: 90 degrees, material: diamond)
[Measurement conditions of surface roughness measuring instrument]
-Reference length (cutoff value of roughness curve λc): 2.5 mm
・ Evaluation length (reference length (cutoff value λc) x 5): 12.5 mm
・ Feed speed of stylus: 0.5 mm / s
・ Vertical magnification: 2000 times ・ Horizontal magnification: 10 times ・ Skid: Not used (no contact with the measurement surface)
・ Cut-off filter type: Gaussian ・ Insensitive zone level: 10%
・ Tp / PC curve: Normal

B1-3. Surface roughness measurement (cutoff value 0.8 mm)
Using a surface roughness measuring instrument (model number: SE-3400 / manufactured by Kosaka Research Institute), the Rz of JIS B0601: 1994 on the uneven surface of the above 20 samples was measured under the following measurement conditions. The average value of the 20 samples was taken as the Rz of each Example and Comparative Example.
[Needle of surface roughness detector]
Product name SE2555N manufactured by Kosaka Research Institute (tip radius of curvature: 2 μm, apex angle: 90 degrees, material: diamond)
[Measurement conditions of surface roughness measuring instrument]
-Reference length (cutoff value of roughness curve λc): 0.8 mm
-Evaluation length (reference length (cutoff value λc) x 5): 4.0 mm
・ Feed speed of stylus: 0.5 mm / s
・ Vertical magnification: 2000 times ・ Horizontal magnification: 10 times ・ Skid: Not used (no contact with the measurement surface)
・ Cut-off filter type: Gaussian ・ Insensitive zone level: 10%
・ Tp / PC curve: Normal

B1-4. Outdoor anti-glare A black acrylic plate was attached to the base material side of the obtained optical sheet via a transparent adhesive to prepare a sample for evaluation. Next, in an environment with an illuminance of 7,000 to 13,000 lux (near a window in fine weather), each evaluation sample was placed horizontally on a horizontal table with a height of about 1 m, and 20 people visually evaluated it from about 50 cm above at various angles. Was evaluated according to the following criteria, and the largest number of evaluations were used as a result.
A: I do not feel the glare of sunlight on the surface of the sample.
B: Depending on the angle, some glare of sunlight may be felt on the sample surface, but it is within the permissible range.
C: I strongly feel the glare of sunlight on the surface of the sample.

B1-5. Resolution The base material side of the obtained optical sheet is attached to the glass on the outermost surface of a commercially available mobile (7.9-inch LCD) via a transparent adhesive, and the illuminance is 7,000 to 13,000 lux (near a window in fine weather). In, each display device was horizontally installed on a horizontal table with a height of about 1 m, and 20 people visually confirmed the icons and characters on the initial screen of each display device from about 30 cm above at various angles. 2 points for icons and characters that can be recognized well, 1 point for icons and characters that can be recognized within the range that does not interfere with operation, and 0 points for icons and characters that are difficult to recognize and interfere with operation. went. Those with an average score of 1.6 points or more for 20 people were designated as A, those with an average score of 1.2 points or more and less than 1.6 points were designated as B, and those with an average score of less than 1.2 points were designated as C.

B1-6. Operability A sample was prepared by laminating a 10 cm square acrylic plate on the base material side of the obtained optical sheet. Next, an operation of moving a finger on the uneven surface of the optical sheet of the sample to change the direction was performed. Each person operates with a light load (a load when the sample is held by the hand opposite to the dominant hand while standing up and operated with the dominant hand) and a heavy load (the sample is placed on the desk and the dominant hand is used). The sample was fixed with the opposite hand, and the load was applied with the dominant hand). Two points that I felt that the direction could be easily changed and the operability was good with any load operation. One point that felt heavy and had some inconvenience in operability. In the operation of at least one of the loads, the finger slips when changing direction or the finger feels heavy when changing direction, which significantly inconveniences operability. Twenty people evaluated what they felt as 0 points. A for 20 people with an average score of 1.6 points or more, B for 1.0 points or more and less than 1.6 points, C for 0.5 points or more and less than 1.0 points, 0.5 points Those less than were designated as D.

B-2. Fabrication of Optical Sheet [Example B1]
On a plastic film (thickness 80 μm triacetyl cellulose resin film (TAC), manufactured by FUJIFILM Corporation, TD80UL), the uneven layer coating liquid B1 of the following formulation is applied, dried at 70 ° C. and a wind speed of 5 m / s for 30 seconds, and then dried. An optical sheet was obtained by irradiating ultraviolet rays in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the integrated light amount was 100 mJ / cm ² to form an uneven layer. The film thickness of the uneven layer was 2.5 μm.

<Concave and convex layer coating liquid B1>
・ Pentaerythritol triacrylate 100 parts (manufactured by Nippon Kayaku Co., Ltd., KAYARAD-PET-30)
・ 14 parts of inorganic particles (atypical silica manufactured by Fuji Silysia Chemical Ltd.)
(Hydrophobic treatment, silane coupling agent, average aggregate particle diameter 2 μm)
-Photopolymerization initiator 5 parts (BASF, Irgacure 184)
-Silicone leveling agent 0.2 parts (TSF4460 manufactured by Momentive Performance Materials)
・ Release agent 2 parts (manufactured by Daikin Industries, Ltd., Optool DAC)
・ Solvent 1 (toluene) 150 parts ・ Solvent 2 (MIBK) 35 parts

[Example B2]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B2 of the following formulation and the film thickness of the uneven layer was 4 μm.
<Concave and convex layer coating liquid B2>
・ Pentaerythritol tetraacrylate 100 parts (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate PE-4)
-Atypical silica particles (hydrophobic treatment: silane coupling agent) 3 parts (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 3 μm)
-Atypical silica particles (hydrophobic treatment: silane coupling agent) 3 parts (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 1.5 μm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyether-modified polysiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., KF6004)
・ Solvent (toluene) 150 parts

[Comparative Example B1]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B3 of the following formulation and the film thickness of the uneven layer was 7 μm.
<Concave and convex layer coating liquid B3>
55 parts of ditrimethylolpropane tetraacrylate (manufactured by SARTOMER, SR355)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone leveling agent 0.25 parts (manufactured by Momentive Performance Materials, TSF4460)
・ 10 parts of spherical polyacrylic-styrene copolymer particles (average particle diameter 6 μm, refractive index 1.52)
・ Colloidal silica fine particles (reactive hydrophobic treatment) 100 parts (manufactured by Nissan Chemical Industry Co., Ltd., solvent MIBK, solid content 30%) (average particle diameter 10 to 15 nm)
・ Solvent (MIBK) 110 copies

[Comparative Example B2]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B4 of the following formulation and the film thickness of the uneven layer was 7 μm.
<Concave and convex layer coating liquid B4>
60 parts of polyfunctional acrylate oligomer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., UV7640B, number of functional groups 6 to 7)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyester-modified polydimethylsiloxane (BYK-CHEMIE, BYK370)
16 parts of spherical polyacrylic-styrene copolymer particles (average particle diameter 3.5 μm, refractive index 1.52)
・ Fumed silica fine particles (hydrophobic treatment: octylsilane treatment) 6 parts (manufactured by Nippon Aerosil Co., Ltd., average particle diameter 10 to 15 nm)
・ Solvent 1 (toluene) 135 parts

[Comparative Example B3]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B5 of the following formulation and the film thickness of the uneven layer was 4 μm.
<Concave and convex layer coating liquid B5>
100 parts of aliphatic polyester skeleton hexafunctional urethane acrylate (manufactured by SARTOMER, CN968)
-Spherical polyacrylic-styrene copolymer particles 3 parts (average particle diameter 2.5 μm, refractive index 1.52)
・ Fumed silica fine particles (hydrophobic treatment: methyl) 3 parts (manufactured by Nippon Aerosil Co., Ltd., average particle diameter 10 to 15 nm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyether-modified polysiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., KF6004)
・ Solvent 1 (toluene) 150 parts ・ Solvent 2 (MIBK) 35 parts

[Comparative Example B4]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B6 of the following formulation and the film thickness of the uneven layer was 3.8 μm.
<Concave and convex layer coating liquid B6>
・ Pentaerythritol tetraacrylate 100 parts (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate PE-4A)
・ Atypical silica particles (hydrophobic treatment: silane coupling agent) 10 parts (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 3.5 μm)
・ Atypical silica particles (hydrophobic treatment: silane coupling agent) 8 parts (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 2 μm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone leveling agent: 0.3 part of polyether-modified polysiloxane (manufactured by Shinetsu Silicone Co., Ltd., KF6004)
・ Solvent (toluene) 150 parts

[Comparative Example B5]
An optical sheet was obtained in the same manner as in Example B1 except that the uneven layer coating liquid B1 of Example B1 was changed to the uneven layer coating liquid B7 of the following formulation and the film thickness of the uneven layer was 4 μm.
<Concave and convex layer coating liquid B7>
・ Pentaerythritol tetraacrylate 100 parts (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate PE-4A)
-Atypical silica particles (hydrophobic treatment: silane coupling agent) 2 parts (manufactured by Fuji Silysia Chemical Ltd., average aggregate particle diameter 3 μm)
-Photopolymerization initiator 3 parts (BASF, Irgacure 184)
-Silicone-based leveling agent: 0.2 parts of polyether-modified polysiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., X-22-2516)
・ Solvent (toluene) 150 parts

From the results in Table 3, it can be seen that the optical sheet of Example B1 can impart outdoor antiglare property and improve operability. The resolution was also good.

B3. Fabrication of Touch Panel An ITO conductive film having a thickness of 20 nm was formed on the transparent substrate side of the optical sheets of Examples B1 and B2 and Comparative Examples B1 to B5 by a sputtering method to form an upper electrode plate. Next, an ITO conductive film having a thickness of about 20 nm was formed on one surface of a tempered glass plate having a thickness of 1 mm by a sputtering method to form a lower electrode plate. Next, an ionizing radiation curable resin (Dot Cure TR5903: Taiyo Ink Co., Ltd.) was printed in dots on the surface of the lower electrode plate having the conductive film as a coating liquid for spacers by a screen printing method, and then ultraviolet rays were emitted with a high-pressure mercury lamp. After irradiation, spacers having a diameter of 50 μm and a height of 8 μm were arranged at intervals of 1 mm.
Next, the upper electrode plate and the lower electrode plate are arranged so that the conductive films face each other, and the edges are bonded with a double-sided adhesive tape having a thickness of 30 μm and a width of 3 mm. The resistance film type touch panel of was manufactured.
The resistance film type touch panels of Examples B1 and B2 had outdoor antiglare properties and had good operability and resolution.

B4. Fabrication of Display Device (1) The optical sheets of Examples B1 and B2 and Comparative Examples B1 to B5 and the surface glass plate of a commercially available ultra-high-definition liquid crystal display device (4.7 inches, pixel density of about 320 ppi) are transparent. The display devices (1) of Examples B1 and B2 and Comparative Examples B1 to B5 were manufactured by laminating via a pressure-sensitive adhesive. At the time of bonding, the uneven surface of the optical sheet was made to face the side opposite to the display element.
When the presence or absence of glare in the obtained display device (1) was visually evaluated, the glare was suppressed in the display devices (1) of Examples B1 and B2, the transfer of external light was small, and the visibility was good. there were. In addition, the display device (1) of Example B1 did not impair the resolution of the ultra-high-definition video.

B5. Preparation of Display Device (2) Examples B1 and B2 and Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and Comparative Examples B1 and B2 and the display devices (2) were prepared except that the base material of the optical sheet was changed to a polyethylene terephthalate film (retamination value of 2,500 nm) having a thickness of 50 μm. Optical sheets of Examples B3 and B4 and Comparative Examples B6 to B10 were produced in the same manner as in Comparative Examples B1 to B5. The physical property values in Table 3 of the optical sheets of Examples B3, B4 and Comparative Examples B6 to B10 are substantially the same as those of Examples B1 and B2 and Comparative Examples B1 to B5.
Commercially available organic EL display device (CIE-xy chromaticity diagram) having an optical sheet of Examples B3, B4 and Comparative Examples B6 to B10 and a polarizing element on a three-color independent organic EL display element having a microcavity structure. The surface glass plate of BT.2020 (coverage rate of 77%) based on the above was bonded to each other via a transparent pressure-sensitive adhesive to prepare display devices (2) of Examples B3 and B4 and Comparative Examples B6 to B10. At the time of bonding, the uneven surface of the optical sheet was made to face the side opposite to the display element.

[Evaluation of display device (2)]
<Gradient color unevenness>
The screen of the display device (2) is displayed in white or substantially white. The screen was visually observed from various angles through polarized sunglasses, and it was evaluated whether or not gradation-like color unevenness could be visually observed. Two points where the gradation-like color unevenness is not visible, one point where the gradation-like color unevenness is very slightly visible, but one that does not interfere with the image quality, the gradation-like color unevenness is clearly visible, and the image quality. Twenty people evaluated the ones that had a great problem with the evaluation criteria of 0 points. A for 20 people with an average score of 1.7 points or more, B for 1.4 points or more and less than 1.7 points, B for 1.0 points or more and less than 1.4 points, 1.0 points Those less than were designated as D. The results are shown in Table 4.

The display element constituting the display device (2) has an extremely wide color gamut and tends to cause gradation-like color unevenness. However, since the display device (2) of Example B3 has an uneven shape having a large Ra and an appropriate randomness, the color unevenness of the gradation tone cannot be visually recognized at all.

1: Resistive film type touch panel, 11: Transparent substrate, 12: Transparent conductive film, 13: Spacer 2: Capacitive touch panel, 21: Transparent substrate, 22: Transparent conductive film (X-axis electrode), 23: Transparent conductive film (Y-axis electrode), 24: Adhesive layer

Claims (9)

A touch panel with irregularities on the surface of the operator.
When a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness, and a vertical load of 100 g is applied to the scratching needle, the scratching needle is reciprocated once at a speed of 10 mm / sec. The static friction coefficient applied to the scratch needle is μs ₁₀ , and a sapphire scratch needle having a tip radius of 0.3 mm is vertically contacted with the uneven surface, and a vertical load of 100 g is applied to the scratch needle at a speed of 20 mm / sec. When the static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way is μs ₂₀ , μs ₁₀ and μs ₂₀ satisfy the following condition (A1).
As for the unevenness, the arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A2), and
The above irregularities are the ten-point average roughness (Rz _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the ten points of JIS B0601: 1994 when the cutoff value is 0.8 mm. A touch panel whose point average roughness (Rz _0.8 ) satisfies the following condition (A5).
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.20 μm (A5) The touch panel according to claim 1, wherein the Rz _2.5 and the Ra _2.5 satisfy the following condition (A3).
5.7 ≤ Rz _2.5 / Ra _2.5 (A3) A claim that the unevenness has the maximum height (Ry _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the Rz _2.5 satisfy the following condition (A6). The touch panel according to 1 or 2.
Ry _2.5 / Rz _2.5 ≤ 1.5 (A6) As for the unevenness, the average inclination angle (θa _2.5 ) of the unevenness when the cutoff value is 2.5 mm and the Ry _2.5 / Rz _2.5 satisfy the following condition (A7). The touch panel according to claim 3.
0.8 ≤ θa _2.5 / (Ry _2.5 / Rz _2.5 ) ≤ 5.0 (A7) The touch panel according to any one of claims 1 to 4, wherein the unevenness is provided on one surface of the optical sheet. The touch panel according to claim 5, wherein the optical sheet comprises a transparent substrate having a retardation value of more than 0 nm and less than 3,000 nm. A display device having irregularities on the outermost surface of the display element on the exit surface side.
When a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness, and a vertical load of 100 g is applied to the scratching needle, the scratching needle is reciprocated once at a speed of 10 mm / sec. The static friction coefficient applied to the scratch needle is μs ₁₀ , and a sapphire scratch needle having a tip radius of 0.3 mm is vertically contacted with the uneven surface, and a vertical load of 100 g is applied to the scratch needle at a speed of 20 mm / sec. When the static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way is μs ₂₀ , μs ₁₀ and μs ₂₀ satisfy the following condition (A1).
As for the unevenness, the arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A2), and
The above irregularities are the ten-point average roughness (Rz _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the ten points of JIS B0601: 1994 when the cutoff value is 0.8 mm. A display device in which the point average roughness (Rz _0.8 ) satisfies the following condition (A5).
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.20 μm (A5) An optical sheet having irregularities on one surface,
When a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness, and a vertical load of 100 g is applied to the scratching needle, the scratching needle is reciprocated once at a speed of 10 mm / sec. The static friction coefficient applied to the scratch needle is μs ₁₀ , and a sapphire scratch needle having a tip radius of 0.3 mm is vertically contacted with the uneven surface, and a vertical load of 100 g is applied to the scratch needle at a speed of 20 mm / sec. When the static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way is μs ₂₀ , μs ₁₀ and μs ₂₀ satisfy the following condition (A1).
As for the unevenness, the arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A2), and
The above irregularities are the ten-point average roughness (Rz _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the ten points of JIS B0601: 1994 when the cutoff value is 0.8 mm. An optical sheet whose point average roughness (Rz _0.8 ) satisfies the following condition (A5).
0.70 ≤ μs ₂₀ / μs ₁₀ ≤ 1.75 (A1)
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.20 μm (A5) This is a method for selecting an optical sheet having irregularities on one surface.
When a scratching needle made of sapphire having a tip radius of 0.3 mm is vertically contacted with the unevenness, and a vertical load of 100 g is applied to the scratching needle, the scratching needle is reciprocated once at a speed of 10 mm / sec. The static friction coefficient applied to the scratch needle is μs ₁₀ , and a sapphire scratch needle having a tip radius of 0.3 mm is vertically contacted with the uneven surface, and a vertical load of 100 g is applied to the scratch needle at a speed of 20 mm / sec. When the static friction coefficient applied to the scratch needle when making one round trip with a length of 10 mm one way is μs ₂₀ , μs ₁₀ and μs ₂₀ satisfy the following condition (A1).
As for the unevenness, the arithmetic mean roughness (Ra _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm satisfies the following condition (A2), and
The above irregularities are the ten-point average roughness (Rz _2.5 ) of JIS B0601: 1994 when the cutoff value is 2.5 mm and the ten points of JIS B0601: 1994 when the cutoff value is 0.8 mm. A method for selecting an optical sheet in which an optical sheet whose point average roughness (Rz _0.8 ) satisfies the following condition (A5) is selected as an optical sheet located at the top of the touch panel.
0.10 μm ≤ Ra _2.5 ≤ 0.60 μm (A2)
0.10 μm ≤ Rz _2.5 -Rz _0.8 ≤ 1.20 μm (A5)

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