WO2022163492A1

WO2022163492A1 - Polarizing plate and display device

Info

Publication number: WO2022163492A1
Application number: PCT/JP2022/001999
Authority: WO
Inventors: 愛実高間; 光星島田
Original assignee: コニカミノルタ株式会社
Priority date: 2021-01-28
Filing date: 2022-01-20
Publication date: 2022-08-04
Also published as: JPWO2022163492A1; TWI826911B; TW202235916A

Abstract

The present invention provides a means that is capable of reducing display unevenness. The present invention relates to a display device which comprises a polarizing plate and a display device unit, wherein: the polarizing plate comprises a polarizer and an optical film; the optical film comprises at least a base material; the base material contains at least a cycloolefin resin; the refractive index difference between the optical film and the polarizer satisfies formula (1); and the RMS granularity of a display image, which is taken from a position that is inclined at 10° to the display screen toward the viewing side when the display device is in a black display state, is from 0.30 to 1.34. Formula (1): 0 ≤ (refractive index of optical film) – (refractive index of polarizer) < 0.02

Description

Polarizing plate and display device

The present invention relates to a polarizing plate and a display device.

In recent years, with the expansion of the use of display devices, there is a demand for higher image quality and higher definition of display devices. Recently, 4K televisions (televisions having approximately four times the number of pixels of full high-definition televisions) are commercially available. Further, in the future, there is a demand for display devices such as 8K televisions that can achieve even higher contrast. As methods for improving the image quality and definition of such display devices, it is known to reduce the pixel size, increase the amount of light, or increase the response speed of an active drive type using thin film transistors. It is

Among such display devices, a liquid crystal display device having a liquid crystal panel in which a light source side polarizing plate, a liquid crystal cell and a viewing side polarizing plate are provided in this order, and a light source for irradiating the liquid crystal panel with light is generally known. . In liquid crystal display devices, various optical films are used for the purpose of protecting polarizers contained in polarizing plates, widening the viewing angle, improving display characteristics, and the like. Conventionally, cellulose ester resins and polycarbonate resins have been used as such optical film materials. In recent years, attention has been focused on resins containing polymers having an alicyclic structure from the viewpoint of high heat resistance, low hygroscopicity, and small photoelastic constant. As an optical film using a resin containing a polymer having an alicyclic structure, JP-A-2016-79210 discloses a stretched film layer made of a thermoplastic resin containing a polymer having a molecular weight of a predetermined value or more, A multilayer film having a cured layer of a coating film of a polyurethane-containing coating liquid provided on at least one surface of the stretched film layer is disclosed. Further, Japanese Patent Application Laid-Open No. 2016-79210 discloses a polarizing plate having the multilayer film and a liquid crystal display device having the multilayer film or a polarizing plate having the same. Further, Japanese Patent Laid-Open No. 2016-79210 also discloses that the multilayer film has excellent adhesion to the polarizer included in the polarizing plate.

Regarding the display device, the present inventors have discovered that, depending on the type of optical film used in the display device, display unevenness recognized as screen roughness is observed when observed from an oblique direction. In recent years, when a display device is industrially produced and a display is performed on the display device, the frequency and degree of display unevenness that is recognized as luminance unevenness differs between display devices. It is confirmed that the variation in quality becomes large. The display unevenness as described above cannot be solved by the multilayer film described in JP-A-2016-79210 or the display device using the polarizing plate having the same, and there is room for improvement.

Therefore, an object of the present invention is to provide means for reducing display unevenness.

The above problems of the present invention can be solved by the following means:
In a display device having a polarizing plate and a display device unit,
The polarizing plate has a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
A display device, wherein the RMS granularity of a display image photographed from a position inclined by 10° from the display surface toward the viewing side when the display device displays black is 0.30 to 1.34.

The above objects of the present invention can also be solved by the following means:
In a display device having a polarizing plate and a display device unit,
The polarizing plate has a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
A display device, wherein the RMS granularity of a display image photographed from a position inclined by 10° from the display surface toward the viewing side when the display device displays black is 0.30 to 1.30.

The above objects of the present invention can also be solved by the following means:
A polarizing plate having a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity of the displayed image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.34. There is a polarizer.

The above objects of the present invention can also be solved by the following means:
A polarizing plate having a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity of a display image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.30. There is a polarizer.

FIG. 4 is a schematic diagram for explaining imaging positions for evaluation of RMS granularity; RMS granularity in a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate (viewing side polarizing plate) arranged on the viewing side (observer side, front side) of the display cell FIG. 4 is a schematic diagram for explaining imaging positions for evaluation of degree; 1 is a schematic diagram showing an example of a basic configuration of a liquid crystal display device according to an embodiment of the present invention; FIG. FIG. 2 is a schematic diagram showing another example of the basic configuration of the liquid crystal display device according to one embodiment of the present invention; It is a photographed image of display unevenness of the liquid crystal display device 7 according to the embodiment of the present invention. It is the photographed image of the display unevenness of the liquid crystal display device 13 according to the comparative example of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings as necessary. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

In this specification, the range "X to Y" means "X or more and Y or less". In addition, unless otherwise specified, operations, physical properties, etc. are measured under the conditions of room temperature (20 to 25° C.)/relative humidity of 40 to 50% RH.

Also, in this specification, (co)polymer is a generic term including copolymers and homopolymers.

In this specification, "(meth)acrylate" is a generic term for acrylate and methacrylate. Similarly, compounds containing (meth) such as (meth)acrylic acid are collective names for compounds having "meta" in their names and compounds not having "meta" in their names.

<Display device>
One aspect of the present invention is a display device comprising a polarizing plate and a display device unit, wherein the polarizing plate comprises a polarizer and an optical film, the optical film comprises at least a substrate, and the substrate comprises at least contains a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
The present invention relates to a display device in which the RMS granularity of a display image photographed from a position inclined by 10° from the display surface toward the viewing side when the display device displays black is 0.30 to 1.34.

A preferred embodiment of the present invention is a display device comprising a polarizing plate and a display device unit, wherein the polarizing plate comprises a polarizer and an optical film, the optical film comprises at least a substrate, and the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1),
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
The present invention relates to a display device in which the RMS granularity of a display image photographed from a position inclined by 10° from the display surface toward the viewing side when the display device displays black is 0.30 to 1.30.

According to the present invention, it is possible to provide means for reducing display unevenness.

The inventors presume the mechanism by which the present invention solves the problem as follows.

By reducing the pixel size in the display device, the control of the linearity of light is improved when the number of pixels is increased and the definition is increased. However, in this case, light interference (moire) or the like is likely to occur between pixel grids. When reducing the pixel size, it is difficult to make the size completely uniform. Further, minute differences in pixel size at different locations within the display device cause differences in the frequency and degree of light interference between pixel grids. As a result, screen roughness may occur. Roughness on the screen is particularly noticeable when viewed from an oblique direction. In addition, even minute differences in pixel size between display devices cause differences in the frequency and degree of occurrence of light interference between pixel grids. Variation in quality also occurs. As a result, display unevenness occurs in the display device.

Since the RMS granularity is related to variations in image density, it is thought that display unevenness is better when the RMS granularity is closer to 0. It was found that the display unevenness is reduced when the value is equal to or more than the value. Also, considering the influence of the refractive index difference between the optical film and the polarizer on the light, it seems that the display unevenness is better when the absolute value is closer to 0 regardless of whether the difference is positive or negative. However, surprisingly, the present inventors found that display unevenness is reduced when the refractive index difference between the optical film and the polarizer (refractive index of the optical film - refractive index of the polarizer) is 0 or more. I found out. As a result of repeated studies, the present inventors have found that the RMS granularity of a photographed image photographed from a specific direction of the display device is set to a specific range, and the optical film in the polarizing plate of the display device and the polarizing By satisfying a predetermined relationship between the difference in refractive index between the two elements, the display unevenness recognized as unevenness in brightness, which appears as the variation in display quality between display devices, can be satisfactorily suppressed, while the display unevenness recognized as roughness of the screen can be suppressed. found to be reduced. It is believed that the reason for this is that the display device of the present invention slightly scatters the light emitted from the display device so as to cancel the interference of light between pixel grids. Although the details are unknown, the above RMS granularity and the above refractive index difference between the optical film and the polarizer influence the scattering properties of the light particularly favorably in eliminating light interference between the pixel gratings. considered to change.

It should be noted that the above mechanism is based on speculation, and its correctness or wrongness does not affect the technical scope of the present invention.

The RMS granularity is one of the graininess evaluation indexes, and is known as the root mean square (RMS) representation of the density variation of a captured image.

In a display device according to an embodiment of the present invention, the RMS granularity (RMS granularity of the display device) of a display image taken from a position tilted 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.34, preferably 0.30 to 1.30.

The above RMS granularity (RMS granularity of the display device) is the polarizer of the polarizing plate (if there are more than one, one of the polarizing plates to be noticed, preferably the viewing side polarizing plate) when the display device is displayed in black. +45°, +135°, +225° (-135°), and +315° (-45°) along the display surface with respect to the absorption axis direction of 10° from the display surface to the viewing side in each direction It represents the average value of the RMS granularity (RMS granularity at a specific angle) of a display image taken from an oblique position.

Thus, in this specification, the average value of the RMS granularities of the individual display images photographed from the above four positions is also simply referred to as "the RMS granularity of the display device." In addition, the RMS granularity of each display image taken from a position tilted 10° from the display surface toward the viewing side at a specific angle along the display surface is also simply referred to as "the RMS granularity at a specific angle".

If the RMS granularity of the display device is less than 0.30, variations in display quality between display devices, particularly display unevenness recognized as luminance unevenness, increase. Further, when the RMS granularity of the display device exceeds 1.30, particularly significantly exceeds 1.34, display unevenness, particularly display unevenness recognized as screen roughness, increases.

In this specification, "on the surface" of a certain part may be "directly above" the certain part, and may include other parts between the part of interest and the certain part.

In this specification, "a position inclined by 10° from the display surface to the viewing side" means that the plane on which the display surface of the display device exists is 0°, and the position used as a reference for photographing the display surface is represents the position on a straight line forming an angle of 10° toward the normal direction (vertical direction) of the observer side (viewing side, front side).

"A position inclined 10 degrees from the display surface toward the viewing side" will be described below with reference to FIG. FIG. 1 is a schematic diagram for explaining imaging positions for evaluating RMS granularity. In FIG. 1, a reference position O is a position used as a reference for photographing the display surface 1 of the display device. Regarding the reference position O, the plane on which the display surface 1 exists is set to 0°, and the normal direction (vertical direction) of the display surface 1 to the observer side (visible side, front side) is 10° toward the Z direction side. The position on the straight line L forming the angle is "the position inclined 10 degrees from the display surface toward the viewing side". A position inclined from the display surface to the viewing side other than this angle is also considered in the same manner.

In the display device according to one embodiment of the present invention, the display device unit includes a display cell, and at least one polarizing plate is arranged on the visible side (observer side, front side) of the display cell of the display device unit. is preferred. Further, it is more preferable that the number of polarizing plates arranged on the viewing side (observer side, front side) of the display cell of the display device unit is one.

In the display device according to one embodiment of the present invention, when the polarizing plate is arranged on the visible side (observer side, front side) of the display cell of the display device unit, when the display device is displayed in black, , a position inclined by 10° from the display surface to the viewing side in each of the directions rotated +45°, +135°, +225°, and +315° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate The average value of the RMS granularity of the display image taken from the display device (the RMS granularity of the display device) is preferably 0.30 to 1.34, more preferably 0.30 to 1.30. The reason for this is that display unevenness is particularly likely to appear in a direction rotated +45°, +135°, +225°, or +315° along the display surface with respect to the absorption axis direction of the viewing side polarizing plate, and the photograph was taken from this position. This is because when the RMS granularity of the image is within the above range, a remarkable effect of reducing display unevenness can be obtained. From the same point of view, from the display surface to the viewing side in each direction rotated +45°, +135°, +225°, or +315° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate All of the RMS granularity (RMS granularity at a specific angle) of a display image taken from a position inclined by 10° are preferably 0.30 to 1.34, particularly preferably 0.30 to 1.30. is more particularly preferred.

Here, the "directions rotated +45°, +135°, +225°, and +315° along the display surface with respect to the absorption axis direction of the polarizer" of the viewer-side polarizing plate are respectively the display surfaces of the display device. Regarding the position used as a reference for photographing, the absorption axis direction of the polarizer of the polarizing plate on the viewing side (observer side, front side) of the display cell is 0 °, and the counterclockwise direction is positive +45 °, +135 °, +225 ° (−135°), and +315° (−45°) represent orientations on the display surface rotated.

Hereinafter, with reference to FIG. 2, an example of “a position inclined 10° from the display surface to the viewing side in a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the viewing side polarizing plate”. described as. FIG. 2 shows a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate (viewing-side polarizing plate) arranged on the viewing side (observer side, front side) of the display cell. 3 is a schematic diagram for explaining imaging positions for evaluation of RMS granularity in FIG. In FIG. 2, a reference position O is a position used as a reference for photographing the display surface 1 of the display device. Further, the direction orthogonal to the absorption axis direction a of the polarizer of the polarizing plate arranged on the viewing side of the display cell on the display surface 1 is the X direction, and the direction of the absorption axis direction a of the polarizer is the Y direction. do. A direction orthogonal to the X direction and the Y direction and on the viewing side (observer side, front side) with respect to the display surface 1 is defined as the Z direction. Here, the Z direction is the normal direction (vertical direction) of the display surface 1 on the observer side (visible side, front side). At this time, "the position inclined by 10° from the display surface to the viewing side in the direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the viewing side polarizing plate" refers to the following position. show. First, regarding the reference position O, consider a direction rotated +45° along the display surface when the direction (Y direction) of the absorption axis direction a of the polarizer of the viewing side polarizing plate on the display surface 1 is set to 0°. . Then, regarding the reference position O in this direction, the plane on which the display surface 1 exists is set to 0°, and the Z direction side, which is the normal direction (perpendicular direction) to the viewer side (viewing side, front side) of the display surface 1 The position on the straight line L (45) forming an angle of 10° toward the viewer is "visible from the display surface in a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the viewing side polarizing plate. position inclined 10° to the side”. In addition, regarding "positions inclined by 10° from the display surface to the viewing side in directions rotated +135°, +225°, and +315° along the display surface with respect to the absorption axis direction of the polarizer of the viewing side polarizing plate" are also considered in the same way as +45° above. In addition, other angles of the viewer-side polarizing plate with respect to the absorption axis direction of the polarizer are also considered in the same way.

From the same point of view, in the display device according to one embodiment of the present invention, when the polarizing plate is arranged on the viewing side (observer side, front side) of the display cell of the display device unit, the display When the device displays black, 10 degrees from the display surface to the viewing side in the direction rotated at 45° intervals from 0° to +360° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate. ° All of the RMS granularity of a display image taken from an oblique position (RMS granularity at a specific angle) is particularly preferably 0.30 to 1.34, more preferably 0.30 to 1.30. More particularly preferred.

When two or more polarizing plates are arranged on the viewing side of the display cell of the display device unit, the RMS granularity is measured by measuring the polarizer of the viewing side polarizing plate located closest to the display cell. may be performed with reference to the absorption axis direction of .

Further, when the display device unit includes a display cell and at least one polarizing plate is arranged on the viewing side (observer side, front side) of the display cell of the display device unit, at least one polarizing plate is arranged on the display cell. is preferably further arranged on the side opposite to the visual recognition side (observer side, front side). In this case, it is more preferable that only one polarizing plate is arranged on the side opposite to the viewing side (observer side, front side) of the display cell of the display device unit.

In the display device according to one embodiment of the present invention, the display device unit includes a display cell, the polarizing plate is not arranged on the viewing side (observer side, front side) of the display cell of the display device unit, At least one polarizing plate may be arranged only on the opposite side (rear side) of the viewing side of the display cell of the display device unit. In this case, the RMS granularity may be measured with reference to the absorption axis direction of the polarizer of the polarizing plate arranged on the back side. At this time, when two or more polarizing plates are arranged on the back side of the display cell of the display device unit, the absorption axis direction of the polarizer of the back side polarizing plate arranged at the position closest to the display cell is the reference. And it is sufficient.

The RMS granularity of the display device and the RMS granularity of the specific angle are not particularly limited as long as they are within the above ranges, but are preferably 0.30 to 1.00, more preferably 0.40 to 0.70. is more preferable, and 0.40 to 0.60 is even more preferable. Within these ranges, display unevenness is further reduced.

　RMS granularity can be measured as follows.

(Step 1) Image acquisition ISO 25 using a camera (e.g., Sony α7sII) and a lens (e.g., Canon EF 70-200mm F2.8L IS II USM) , 600 and F 2.8, the display surface of the liquid crystal display device is photographed from a position inclined by 10° from the display surface to the viewing side in a dark room. Note that the distance between the camera and the reference position for photographing the display surface is 50 cm. In addition, you may perform imaging|photography using a general-purpose camera.

In the calculation of the RMS granularity of the display device, +45 along the display surface with respect to the absorption axis direction of the polarizer of the polarizer (if there are multiple polarizers, one of the polarizers to be focused on, preferably the viewer side polarizer) , +135°, +225° (-135°), and +315° (-45°).

(Step 2) Analysis of Obtained Image RMS granularity is calculated from the photographed image according to the following procedure:
1. Read the obtained photographed image as two-dimensional (planar) data using free software (imageJ);
2. Set a rectangular evaluation area of 2.8 cm x 4 cm in the actual captured image;
3. Grayscale using free software (ImageJ);
4. If necessary, perform background correction of the two-dimensional data read in the evaluation area;
5. RMS granularity is calculated from standard deviation σ of gray values (pixel values) in gray scale. That is, let this standard deviation σ be the RMS granularity of the displayed image at this measurement angle (angle along the display surface) (RMS granularity at a specific angle);
6, +45°, +135°, +225° ( -135°) and +315° (-45°), the average of the RMS granularity (RMS granularity at a specific angle) of the display image taken from a position tilted 10° from the display surface to the viewing side A value (arithmetic mean value) is calculated and taken as the RMS granularity of the display device.

Here, the free software ImageJ is ImageJ1.32S created by WayneRasband. On the other hand, software such as WinROOF may be used as the software used in 1 above.

For example, even though the right and left halves of the image have the same brightness, the background correction is output as different brightness, or it gradually changes from the left to the right of the image. This is done when the image is output as a result of brightening, and the density gradient is approximated by a polynomial to cancel the density gradient mathematically.

The standard deviation σ of gray values in grayscale is calculated by the following method:
A population of _N gray value data x ₁ , x ₂ , .

Next, using the population mean m obtained above, variance σ ² is obtained by the following formula (II).

Let the positive ^square root of this variance σ2 be the standard deviation σ.

The details of the evaluation method of RMS granularity are described in Examples.

The RMS granularity of the display device varies depending on the optical properties such as the refractive index of the cycloolefin resin substrate (substrate containing the cycloolefin resin) described later, the optional functional layer described later, and the polarizer. do. The method for controlling the refractive index of the cycloolefin resin substrate (substrate containing the cycloolefin resin), the optional functional layer, and the optical film containing these will be described later. The RMS granularity of the display device decreases as the difference between the refractive index of the optical film containing the cycloolefin resin substrate (the substrate containing the cycloolefin resin) and the refractive index of the polarizer decreases. It tends to increase as the difference increases. However, display unevenness occurs even if the RMS granularity of the display device is too small as described above. Instead of reducing the difference between the index and the refractive index of the polarizer, the RMS granularity of the display should be in the optimum range.

Details of the polarizing plate and the display device unit included in the display device according to one embodiment of the present invention will be described below.

[Polarizer]
A display device according to an embodiment of the present invention includes one or more polarizing plates. At least one of the polarizing plates included in the display device according to one embodiment of the invention includes a polarizer and one or more optical films. Moreover, it is preferable that all of the polarizing plates included in the display device according to one embodiment of the present invention include a polarizer and one or more optical films.

At least one of the polarizing plates included in the display device according to one embodiment of the present invention includes one or more optical films. The number of optical films contained in the polarizing plate is not particularly limited, but is preferably two or more, particularly preferably two. Moreover, the polarizing plate preferably has at least one optical film on each of both surfaces of the polarizer, and preferably has one optical film on each of both surfaces of the polarizer.

(Optical film containing substrate containing cycloolefin resin)
- Substrate containing cycloolefin resin At least one of the polarizing plates included in the display device according to one embodiment of the present invention includes an optical film containing a substrate containing a cycloolefin resin. The optical film may be composed only of a substrate containing a cycloolefin resin, or may further have one or more functional layers described later on a substrate containing a cycloolefin resin. .

In at least one of the polarizing plates included in the display device according to one embodiment of the present invention, an optical film containing a substrate containing a cycloolefin resin may be arranged on one surface of the polarizer, It may be arranged on both sides.

That is, in at least one of the polarizing plates included in the display device according to one embodiment of the present invention, at least one of the optical films included in the polarizing plate includes a base material containing a cycloolefin resin. Of the optical films included in the polarizing plate, at least one of the optical films arranged on one surface of the polarizer preferably includes a substrate containing a cycloolefin resin. At this time, one or more optical films may be arranged on the other surface of the polarizer, or no optical film may be arranged. It is preferable that one optical film is disposed on one surface of the polarizer of the polarizing plate, and that the optical film includes a base material containing a cycloolefin resin. At this time, one or more optical films may be arranged on the other surface of the polarizer, or no optical film may be arranged, but one other optical film described later is arranged. preferably.

Hereinafter, the base material containing the cycloolefin resin is also simply referred to as the "cycloolefin resin base material".

A base material containing a cycloolefin resin includes a cycloolefin resin.

The cycloolefin resin is not particularly limited as long as it is a (co)polymer containing a structural unit having an alicyclic structure. A (co)polymer containing a structural unit having an alicyclic structure may have an alicyclic structure in its main chain or may have an alicyclic structure in its side chain. Among these, a (co)polymer having an alicyclic structure in the main chain is preferable from the viewpoint of refractive index control.

Alicyclic structures include, for example, saturated alicyclic hydrocarbon (cycloalkane) structures, unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures, and the like. Among them, a cycloalkane structure or a cycloalkene structure is preferable, and a cycloalkane structure is particularly preferable, from the viewpoint of mechanical strength, heat resistance, and the like.

Although the number of carbon atoms constituting the alicyclic structure is not particularly limited, it is preferably 4 or more, more preferably 5 or more per alicyclic structure. If it is the said range, storage stability will become better. In addition, the number of carbon atoms constituting the alicyclic structure is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less per alicyclic structure. . If it is the said range, the handleability of a film will become more favorable.

As the cycloolefin resin, a (co)polymer containing structural units derived from a cycloolefin monomer is preferable. A cycloolefin monomer is a compound having a ring structure formed by carbon atoms and having a polymerizable carbon-carbon double bond in the ring structure. The polymerizable carbon-carbon double bond is not particularly limited, but includes, for example, a polymerizable carbon-carbon double bond such as ring-opening polymerization. Moreover, the ring structure of the cycloolefin monomer includes, for example, a monocyclic ring, a polycyclic ring, a condensed polycyclic ring, a bridged ring, and a polycyclic ring in which these are combined. Among these, polycyclic cycloolefin monomers are preferable from the viewpoint of controlling the refractive index.

As the cycloolefin resin, a (co)polymer containing a structural unit derived from a monomer containing a norbornene structure, a (co)polymer containing a structural unit derived from a monomer containing a monocyclic cyclic olefin, a cyclic Examples thereof include (co)polymers containing structural units derived from monomers containing a conjugated diene structure. These (co)polymers may be in a hydrogenated state.

Although the cycloolefin resin is not particularly limited, for example, tricyclo[4.3.0.1 ^2,5 ]dec-3-ene, tricyclo[4.3.0.1 ^2,5 ]deca-3,7- Diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 ^2,5 ]dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4.0 ^{.1 2} , 5 . 1 ^7,10 ]dodeca-3-ene (common name: tetracyclododecene), compounds 1 to 34 described later, and norbornene structures such as derivatives of these compounds (for example, those having substituents on the ring) monomer; monomers such as 1,3-dimethyldodecahydrocyclopenta[a]indene and derivatives thereof (for example, those having a substituent on the ring); is mentioned. Compound 5, which will be described later, is bicyclo[2.2.1]hept-2-ene (common name: norbornene). Here, examples of substituents include an alkyl group, an alkylene group, and a polar group. In addition, these substituents may be the same or different and a plurality of them may be bonded to the ring. The type of polar group is not particularly limited, but examples thereof include heteroatoms, atomic groups having heteroatoms, and the like. Examples of heteroatoms include, but are not limited to, oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, and halogen atoms. Specific examples of the polar group include, but are not limited to, carboxy group, carbonyl group, oxycarbonyl group, epoxy group, hydroxy group, oxy group, ester group, silanol group, silyl group, amino group, nitrile group, and sulfonic acid group. , groups other than polar groups substituted with these groups, groups other than polar groups linked via these groups, and the like.

The cycloolefin resin is not particularly limited, but examples of (co)polymers containing structural units derived from monomers containing monocyclic cyclic olefins include monocyclics such as cyclohexene, cycloheptene, and cyclooctene. (co)polymers containing structural units derived from cyclic olefin monomers having

The cycloolefin resin is not particularly limited. Examples include 1,2- or 1,4-addition polymers of cyclic conjugated diene monomers such as pentadiene and cyclohexadiene, and hydrogenated products thereof.

Among these, a (co)polymer containing structural units derived from a monomer containing a norbornene structure is preferable from the viewpoint of controlling the refractive index. The (co)polymer containing structural units derived from a monomer containing a norbornene structure is not particularly limited, but for example, ring-opening (co)polymers of monomers containing a norbornene structure, and hydrogenated products thereof ; addition (co)polymers of monomers containing a norbornene structure, hydrogenated products thereof, and the like. Here, the ring-opened polymer of a monomer containing a norbornene structure is not particularly limited, but for example, a ring-opened homopolymer of one type of monomer containing a norbornene structure, two or more types of norbornene structure-containing Ring-opening copolymers of monomers, and ring-opening copolymers of a monomer having a norbornene structure and a monomer other than the monomer having a norbornene structure copolymerizable therewith can be mentioned. Further, the addition polymer of a monomer containing a norbornene structure is not particularly limited. and addition copolymers of a monomer containing a norbornene structure and a monomer other than the monomer containing a norbornene structure copolymerizable therewith. Among these, from the viewpoint of improving the uniformity of the surface, a copolymer containing a structural unit derived from a monomer containing a norbornene structure and a structural unit derived from a monomer other than the monomer containing a norbornene structure is preferred, a monomer containing a norbornene structure, a ring-opening copolymer of a monomer other than a monomer containing a norbornene structure copolymerizable therewith, or a monomer containing a norbornene structure, and Addition copolymers with monomers other than monomers containing copolymerizable norbornene structures are more preferred.

A preferred example of the cycloolefin resin is not particularly limited, but includes a (co)polymer containing a structural unit derived from a cycloolefin monomer represented by the following general formula (A). The (co)polymer is a type of (co)polymer containing structural units derived from a monomer having a norbornene structure. The (co)polymer is particularly preferred when producing a cycloolefin resin base material by a solution casting method.

Each R in general formula (A) independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, or a polar group. Moreover, a and b in the general formula (A) each independently represent an integer of 0 or more.

A preferred example of the cycloolefin resin is not particularly limited, but includes a structural unit derived from a cycloolefin monomer represented by the following general formula (A-1) or general formula (A-2) below ( co) polymers and the like. The (co)polymer is a type of (co)polymer containing structural units derived from a monomer having a norbornene structure. The (co)polymer is particularly preferred when producing a cycloolefin resin base material by a solution casting method.

First, the cycloolefin monomer represented by general formula (A-1) will be described.

R ¹ to R ⁴ in general formula (A-1) each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, or a polar group. However, except when all of R ¹ to R ⁴ are hydrogen atoms, there is no case where R ¹ and R ² are hydrogen atoms at the same time, or R ³ and R ⁴ are hydrogen atoms at the same time.

Although the halogen atom is not particularly limited, it is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. The hydrocarbon group having 1 to 30 carbon atoms is not particularly limited, but is preferably an alkyl group having 1 to 30 carbon atoms. The polar group is not particularly limited, but includes a carboxy group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amido group, a cyano group, a group in which these groups are bonded via a linking group such as a methylene group, It is preferably a hydrocarbon group to which a polar divalent organic group such as a carbonyl group, an ether group, a silyl ether group, a thioether group, or an imino group is bonded as a linking group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group and an allyloxycarbonyl group are more preferable. Moreover, from the viewpoint of ensuring solubility during solution film formation, an alkoxycarbonyl group or an allyloxycarbonyl group is more preferable.

At least one of R ¹ to R ⁴ is preferably a polar group from the viewpoint of ensuring the solubility of the cycloolefin resin during solution casting.

p in general formula (A-1) represents an integer of 0 to 2. From the viewpoint of enhancing the heat resistance of the film, p is preferably 1-2. This is because when p is 1 to 2, the resulting resin becomes bulky and the glass transition temperature tends to be improved.

Next, the cycloolefin monomer represented by general formula (A-2) will be explained.

R ⁵ in general formula (A-2) represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. Among them, R ⁵ is preferably a hydrocarbon group having 1 to 3 carbon atoms.

R ⁶ in general formula (A-2) represents a polar group or a halogen atom. Although the polar group is not particularly limited, it is preferably a carboxy group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amido group, or a cyano group. A halogen atom is not particularly limited, but is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Among these, ^R6 is preferably a polar group, more preferably a carboxy group, a hydroxy group, an alkoxycarbonyl group or an allyloxycarbonyl group. Moreover, from the viewpoint of ensuring solubility during solution film formation, an alkoxycarbonyl group or an allyloxycarbonyl group is more preferable.

By using the cycloolefin monomer represented by the general formula (A-2), the symmetry of the molecule is lowered, and the diffusion movement of the resin during solvent volatilization is easily promoted.

In general formula (A-2), p represents an integer of 0-2.

Specific examples of the structures of general formulas (A-1) and (A-2) are shown below.

By increasing the ratio of the alicyclic structure in the cycloolefin resin, the refractive index can be further lowered.

The cycloolefin monomers constituting the cycloolefin resin (that is, the cycloolefin monomers for constituting the cycloolefin resin) can be used singly or in combination of two or more.

The cycloolefin resin may be a copolymer of a cycloolefin monomer and a monomer other than the cycloolefin monomer, or a hydrogenated product thereof. A monomer other than the cycloolefin monomer constituting the cycloolefin resin (i.e., a monomer other than the cycloolefin monomer for constituting the cycloolefin resin) is used alone, or two More than one species can be used together.

As described above, the cycloolefin resin is a (co)polymer containing structural units derived from a monomer having a norbornene structure (the (co)polymer may be in a hydrogenated state). is preferred. As the cycloolefin resin, a copolymer containing a structural unit derived from a monomer containing a norbornene structure and a structural unit derived from a monomer other than the monomer containing a norbornene structure (the copolymer may be in a hydrogenated state). Here, the other monomer copolymerizable with the monomer having a norbornene structure may be a cycloolefin monomer or a monomer other than the cycloolefin monomer. Other monomers copolymerizable with a monomer containing a norbornene structure are not particularly limited, for example, a monomer containing a norbornene structure that is capable of ring-opening copolymerization with a monomer containing a norbornene structure and monomers other than monomers having a norbornene structure, which are addition-copolymerizable with monomers having a norbornene structure.

The monomer other than the norbornene structure-containing monomer, which is ring-opening copolymerizable with the norbornene structure-containing monomer, is not particularly limited. Examples include monomers other than monomers containing a norbornene structure such as cyclopentadiene and derivatives thereof.

The monomer other than the norbornene structure-containing monomer, which can be addition-copolymerized with the norbornene structure-containing monomer, is not particularly limited, and examples thereof include unsaturated double bond-containing compounds and vinyl-based cyclic hydrocarbons. compounds, (meth)acrylate compounds, and the like.

The unsaturated double bond-containing compound (excluding vinyl-based cyclic hydrocarbon compounds and (meth)acrylate compounds described below) is not particularly limited, but examples thereof include ethylene, propylene, 1-butene, and the like having 2 to 20 carbon atoms ( Preferably 2 to 12, more preferably 2 to 8) α-olefins and derivatives thereof, and non-olefins such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene A conjugated diene and the like can be mentioned. Among these, unsaturated double bond-containing compounds are preferred. As the unsaturated double bond-containing compound, an α-olefin having 2 to 20 carbon atoms (preferably 2 to 12, more preferably 2 to 8 carbon atoms) is more preferred, and ethylene is even more preferred. As the unsaturated double bond-containing compound, an unsaturated double bond-containing compound having a hydroxy group is preferable, and a monomer having a structure represented by the following formula (M1) is more preferable.

Here, R ₁₁ above is an organic group. The organic group for R ₁₁ is not particularly limited, but examples thereof include electron-donating groups such as alkyl groups and methoxy groups. Among these, R ₁₁ is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and a butyl group. is particularly preferred.

The vinyl-based cyclic hydrocarbon compound is not particularly limited, but includes, for example, vinylcyclopentene-based monomers such as 4-vinylcyclopentene, 2-methyl-4-isopropenylcyclopentene, and derivatives thereof.

The (meth)acrylate compound is not particularly limited. derivatives and the like. Among these, a (meth)acrylate compound having a hydroxy group is preferable. The (meth)acrylate compound having a hydroxy group is not particularly limited, but examples include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxy Propane-1,2-diyl di(meth)acrylate, glycerin mono(meth)acrylate, diglycerin mono(meth)acrylate, diglycerin tri(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol mono(meth)acrylate acrylates, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta( meth)acrylate, sorbitol di(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, sorbitol mono(meth)acrylate diglycerin di(meth)acrylate, isocyanuric acid EO modified A diacrylate etc. are mentioned.

Among these, a (meth)acrylate compound having a hydroxy group is preferred, 2-hydroxyethyl (meth)acrylate (also known as 2-hydroxyethyl (meth)acrylate) is more preferred, and 2-hydroxyethyl acrylate (also known as acrylic Acid 2-hydroxyethyl) is more preferred.

In a copolymer containing a structural unit derived from a monomer containing a norbornene structure and a structural unit derived from a monomer other than a monomer containing a norbornene structure, a monomer other than a monomer containing a norbornene structure The mers can be used singly or in combination of two or more.

Preferred cycloolefin resins include, for example, tricyclo[4.3.0.1 ^2,5 ]dec-3-ene and tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene (common name: tetracyclododecene) and hydrogenated copolymer of monomers containing 1,3-dimethyldodecahydrocyclopenta[a]indene, bicyclo [2.2.1] Copolymers of monomers containing hept-2-ene (common name: norbornene) and ethylene, and the like. Among these, tricyclo[4.3.0.1 ^2,5 ]dec-3-ene and tetracyclo[4.4.0.1 ^2,5 . Hydrogenation of Copolymers of 1 ^7,10 ]dodeca-3-ene (common name: tetracyclododecene), 1,3-dimethyldodecahydrocyclopenta[a]indene and 2-hydroxyethyl acrylate Preferable examples include a copolymer of a compound, bicyclo[2.2.1]hept-2-ene (common name: norbornene) and ethylene.

Ratio of the mass of the monomer having an alicyclic structure to the total mass of the monomer having an alicyclic structure and the monomer having no alicyclic structure for constituting the cycloolefin resin is not particularly limited. However, it is preferred that the proportion is between 30 and 50% by weight. Within this range, the refractive index of the cycloolefin resin base material tends to be an appropriate value. As a result, display unevenness is further reduced.

A monomer containing a norbornene structure for constituting a copolymer containing structural units derived from a monomer containing a norbornene structure (the copolymer may be in a hydrogenated state); The ratio of the mass of the monomer containing norbornene structure to the total mass of the monomers other than the monomer containing norbornene structure is not particularly limited. However, it is preferred that the proportion is between 30 and 50% by weight. Within this range, the refractive index of the cycloolefin resin base material tends to be an appropriate value. As a result, display unevenness is further reduced.

Although the weight average molecular weight (Mw) of the cycloolefin resin is not particularly limited, it is preferably 30,000 or more, more preferably 35,000 or more, and even more preferably 40,000 or more. Also, the weight average molecular weight (Mw) of the cycloolefin resin is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 150,000 or less. Within these ranges, the cycloolefin resin has better heat resistance, water resistance, chemical resistance, mechanical properties, and moldability as a film.

In addition, the dispersion degree (Mw/Mn) of the cycloolefin resin is not particularly limited, but is preferably 1.2 or more, more preferably 1.5 or more, and further preferably 1.8 or more. preferable. Also, the degree of dispersion (Mw/Mn) of the cycloolefin resin is preferably 3.5 or less, more preferably 3.0 or less, and even more preferably 2.7 or less.

The number average molecular weight (Mn) and weight average molecular weight (Mw) can be measured in terms of polystyrene by gel permeation chromatography (GPC).

Although the glass transition temperature (Tg) of the cycloolefin resin is not particularly limited, it is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. Within these ranges, deformation due to use under high temperature conditions or secondary processing such as coating and printing is less likely to occur. Also, the glass transition temperature (Tg) of the cycloolefin resin is preferably 190° C. or lower, more preferably 180° C. or lower, and even more preferably 170° C. or lower. Within these ranges, molding becomes easier, and the possibility of the resin deteriorating due to heat during molding becomes lower. The Tg of the cycloolefin resin can be measured according to JIS K 7121-1987.

A commercially available product or a synthetic product may be used as the cycloolefin resin. Examples of commercially available products include, but are not limited to, ARTON (registered trademark, hereinafter the same) G (eg, ARTON G7810) manufactured by JSR Corporation, ARTON F, ARTON R, and ARTON RX. be done.

The method for synthesizing the cycloolefin resin is not particularly limited, and known methods can be used. For example, a ring-opening polymer of a monomer containing a norbornene structure is not particularly limited, but can be produced, for example, by polymerizing or copolymerizing monomers in the presence of a ring-opening polymerization catalyst. Moreover, the addition polymer of a monomer containing a norbornene structure is not particularly limited, but can be produced, for example, by polymerizing or copolymerizing a monomer in the presence of an addition polymerization catalyst. The hydrogenated product of the ring-opening polymer and the addition polymer described above is not particularly limited, but for example, in the solution of the ring-opening polymer and the addition polymer, a hydrogenation catalyst containing a transition metal such as nickel and palladium In the presence of carbon-carbon unsaturated bonds can be produced by hydrogenation, preferably greater than 90%. In addition, as a method for synthesizing the cycloolefin resin, based on the method described in JP-A-2010-235719 and JP-A-2018-55044, if necessary, the type, amount, ratio, etc. of the monomer, Other methods may be used in which the types, amounts, ratios, etc. of the components used in the synthesis are appropriately changed.

The cycloolefin resins can be used singly or in combination of two or more.

The content of the cycloolefin resin in the cycloolefin resin base material is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 90% by mass or more. More preferred. If it is the said range, the handleability of a film will become more favorable. In addition, the content of the cycloolefin resin in the cycloolefin resin base material is preferably 100% by mass or less, more preferably 99.9% by mass or less, and 99.5% by mass or less. is more preferred. Within the above range, the amount of components other than the cycloolefin resin added can be increased, making it easier to further improve the effects of the present invention and to impart other desired functions.

The cycloolefin resin substrate preferably contains particles. That is, the cycloolefin resin substrate preferably contains at least one kind of particles. The particles act to further reduce display unevenness. Hereinafter, the particles contained in the cycloolefin resin substrate are also simply referred to as "substrate particles".

The base particles are not particularly limited, but examples include organic particles, inorganic particles, organic-inorganic composite particles, and the like.

Examples of inorganic particles include, but are not limited to, silicon dioxide (silica), titanium dioxide, low order titanium oxide, magnesium oxide, tin oxide, indium oxide, antimony oxide, aluminum oxide, zirconium dioxide, antimony, fluorine or phosphorus. Inorganic oxides such as doped tin oxide, antimony, tin or fluorine-doped indium oxide, calcium carbonate, magnesium carbonate, barium sulfate, strontium sulfate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated silicic acid Inorganic substances such as calcium, aluminum silicate, magnesium silicate and calcium phosphate are included. An inorganic material can be used individually by 1 type, or can use 2 or more types together. Among these, particles made of the above inorganic materials or combinations thereof are preferable, and aluminum oxide (aluminum oxide particles, particulate aluminum oxide) is more preferable.

The organic particles are not particularly limited, but examples include acrylic resins such as poly(meth)acrylate and polymethyl(meth)acrylate, styrene resins such as polystyrene, acrylonitrile resins such as poly(meth)acrylonitrile, cellulose acetate, and cellulose acetate. Examples include cellulose resins such as propionate, silicone resins, fluororesins, and crosslinked products thereof. An organic material can be used individually by 1 type, or can use 2 or more types together. Among these, particles made of the above organic materials, combinations thereof, or crosslinked materials thereof are preferred.

The organic-inorganic composite particles are not particularly limited, but include, for example, multi-layered particles including a core layer made of one of the inorganic material and the organic material and a shell layer made of the other of them. An inorganic material or an organic material can be used individually by 1 type, respectively, or can use 2 or more types together.

The substrate particles may be surface-treated particles (surface-treated particles). In the case of surface treatment, materials used for surface treatment include heterogeneous inorganic oxides such as silicon oxide and zirconium oxide, metal hydroxides such as aluminum hydroxide, organic acids such as stearic acid, and hydrolyzable organic silicon. compounds and the like. Each surface treatment can be used singly or in combination of two or more. The surface-treated particles are not particularly limited, but include, for example, particles obtained by treating the surface of particles made of the above inorganic material with a hydrolyzable organosilicon compound. Here, in the particles subjected to such treatment, the surfaces of the particles made of an inorganic material are usually modified with a hydrolyzate of an organosilicon compound.

The surface treatment method and the type of surface-treated particles are not particularly limited, and known surface treatment methods and known surface-treated particles can be used. For example, the method of organosilicon compound modification treatment and the organosilicon compound-modified particles described in paragraphs "0105" to "0128" of JP-A-2016-157068 can be used.

Although the average primary particle size of the substrate particles is not particularly limited, it is preferably 1 nm or more. Within the above range, luminance unevenness among display devices is reduced, and display quality variation among display devices is further reduced. Also, the average primary particle size of the substrate particles is not particularly limited, but is preferably 100 nm or less. If it is the said range, the transparency of a film will improve more. The average primary particle size of the substrate particles can be measured using a transmission electron microscope (TEM) (H-7650 manufactured by Hitachi High-Tech Co., Ltd.).

Although the average secondary particle size of the substrate particles is not particularly limited, it is preferably 10 nm or more. Within the above range, luminance unevenness among display devices is reduced, and display quality variation among display devices is further reduced. Also, the average secondary particle size of the substrate particles is not particularly limited, but is preferably 300 nm or less. If it is the said range, the transparency of a film will improve more. The average secondary particle size of the substrate particles can be determined by a method of directly measuring the size of the secondary particles from an electron micrograph of the layer (cycloolefin resin substrate). Specifically, in this method, the particle image is measured with a transmission electron microscope (TEM) (H-7650 manufactured by Hitachi High-Tech Co., Ltd.), and 100 randomly selected secondary particles equivalent to circles of equal area An average value of the diameters is obtained, and this value is defined as the average secondary particle size.

A commercial product or a synthetic product may be used for the substrate particles. Examples of commercially available products include, but are not limited to, R972V and R812 manufactured by Nippon Aerosil Co., Ltd., aluminum oxide nanoparticles manufactured by EM Japan Co., Ltd., and the like.

The substrate particles can be used singly or in combination of two or more.

The content of the substrate particles in the cycloolefin resin substrate is not particularly limited, but is preferably 0.1% by mass or more relative to the total mass of the cycloolefin resin substrate. If it is the said range, adjustment of a refractive index will become easier. Moreover, the content of the substrate particles in the cycloolefin resin substrate is preferably 10% by mass or less with respect to the total mass of the cycloolefin resin substrate. If it is the said range, the transparency of a film will improve more.

In one embodiment of the present invention, the cycloolefin resin substrate may not contain substrate particles.

The cycloolefin resin base material may further contain components other than the components described above as long as the effects of the present invention are not impaired. Examples of other components include, but are not particularly limited to, components used in the field of known optical films and the field of functional layers for known optical applications. Specifically, thermoplastic resins other than cycloolefin resins (excluding organic particles that are the base particles described above), retardation modifiers, wavelength dispersion modifiers, plasticizers, ultraviolet absorbers, antioxidants, hydrogen bonds ionic solvents, ionic surfactants and the like, but are not limited to these.

In one embodiment of the present invention, the thickness of the cycloolefin resin base material is not particularly limited, but is preferably 10 μm or more. Within this range, the handleability of the film is good. Moreover, the thickness of the cycloolefin resin substrate is preferably 60 μm or less. Within this range, it can also be applied to flexible devices.

In one embodiment of the present invention, the refractive index of the cycloolefin resin base material is not particularly limited, but is preferably 1.500 or more, more preferably 1.525 or more. Moreover, the refractive index of the cycloolefin resin substrate is preferably 1.535 or less. Within these ranges, it becomes easier for the difference in refractive index between the optical film containing the cycloolefin resin substrate and the polarizer to satisfy formula (1) described below. It is particularly preferred that the refractive index at the nD:D line (589 nm) at 25° C. satisfies the above range. The refractive index can be measured with a multi-wavelength Abbe refractometer (trade name: DR-M2, manufactured by Atago Co., Ltd.).

- Functional layer The optical film preferably has a functional layer in addition to the above cycloolefin resin substrate. That is, in at least one of the polarizing plates included in the display device according to one embodiment of the present invention, at least one of the optical films included in the polarizing plate includes, in addition to a base material containing a cycloolefin resin, It preferably contains a functional layer. By using an optical film having a functional layer in addition to a substrate, it may be possible to impart desired functions and further reduce display unevenness. The reason for this is that, as described in the presumed mechanism above, the display device of the present invention dares to finely scatter the light emitted from the display device so as to cancel out the light interference between the pixel grids. We believe that the layers act to make this scattering more appropriate.

The optical film may have only one functional layer, or may have two or more. In addition, the functional layer may be provided on one side or both sides of the substrate containing the cycloolefin resin, but is preferably provided on one side. .

Of the optical films contained in the polarizing plate, at least one of the optical films arranged on one side of the polarizer more preferably contains a functional layer in addition to the substrate containing the cycloolefin resin. Further, it is more preferable that all of the optical films arranged on one surface of the polarizer further include a functional layer in addition to the substrate containing the cycloolefin resin. At this time, one or more optical films may be arranged on the other surface of the polarizer, or no optical film may be arranged.

Among the optical films included in the polarizing plate, one optical film is arranged on one surface of the polarizer, and the optical film further includes a functional layer in addition to the base material containing the cycloolefin resin. It is particularly preferred to include At this time, one or more optical films may be arranged on the other surface of the polarizer, or no optical film may be arranged. Among these, it is preferable to dispose one other optical film, which will be described later, on the other surface of the polarizer.

The functional layer is not particularly limited, and includes functional layers used for optical purposes. Specifically, antiblocking layer, release layer, easy adhesion layer, antistatic layer, hard coat layer, antireflection layer, antiglare layer, antifouling layer, barrier layer, buffer layer, slippery layer, adhesive layer etc., but not limited to these. Among these, it is preferably a functional layer other than the adhesive layer, more preferably an easy-adhesion layer or a hard coat layer, and even more preferably an easy-adhesion layer.

Also, the functional layer is preferably a hardening layer.

Although the functional layer is not particularly limited, it preferably contains a base resin such as urethane resin, acrylic resin, epoxy resin, polyvinyl acetal resin, or the like. For example, when the functional layer is an easy-adhesion layer, the easy-adhesion layer preferably contains a urethane resin. Further, for example, when the functional layer is a hard coat layer, the hard coat layer preferably contains an acrylic resin.

The functional layer containing the urethane resin is not particularly limited, but examples thereof include a layer obtained by curing a layer of a coating liquid containing a polyurethane precursor or polyurethane (coating liquid layer).

The urethane resin is not particularly limited, but includes, for example, the polyurethane itself added as a raw material for the coating liquid, the polyurethane product obtained through the curing reaction with isocyanate or its derivative and alcohol or its derivative, and the curing reaction of the urethane prepolymer. Polyurethane products and the like obtained through Therefore, the urethane resin is preferably polyurethane or a crosslinked product thereof.

The polyurethane itself, the urethane prepolymer and the polyurethane product are not particularly limited, but for example, a polyol component having an average of 2 or more hydroxyl groups per molecule and an average of 2 or more isocyanate groups per molecule, respectively. Examples thereof include polyurethanes obtained by reacting with polyisocyanate components possessed.

The polyol component is not particularly limited, but examples include (1) aliphatic polyester polyol, (2) polyether polyol, (3) polycarbonate polyol, (4) polyester ether polyol, and (5) polyethylene terephthalate polyol. be done.

(1) The aliphatic polyester polyol is not particularly limited, but examples thereof include a reaction product obtained by reacting an aliphatic polyol with an aliphatic polybasic acid. Examples of aliphatic polyols include, but are not limited to, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, glycerin, trimethylolpropane and the like. An aliphatic polyol can be used individually by 1 type, or can use 2 or more types together by arbitrary ratios. Examples of aliphatic polybasic acids include, but are not limited to, polycarboxylic acids and anhydrides thereof. The polyvalent carboxylic acid is not particularly limited, and examples thereof include dicarboxylic acids such as adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid, and trimellitic acid. and the like. A polybasic acid can be used individually by 1 type, or can use 2 or more types together by arbitrary ratios.

(2) The polyether polyol is not particularly limited, but includes, for example, poly(oxypropylene ether) polyol, poly(oxyethylene-propylene ether) polyol, and the like.

(3) _{Polycarbonate} polyols are not particularly limited, but may be, for example, a X represents the number of structural units of the molecule and is usually an integer of 5 to 50). Such a polycarbonate polyol is not particularly limited, but can be obtained, for example, by a transesterification method in which a saturated aliphatic polyol and a substituted carbonate are reacted under conditions in which hydroxyl groups are excessive. Alternatively, for example, it can be obtained by a method of reacting a saturated aliphatic polyol with phosgene, or, if necessary, further reacting a saturated aliphatic polyol thereafter. In this case, the substituted carbonate is not particularly limited, and examples thereof include diethyl carbonate, diphenyl carbonate and the like. Moreover, these can be used individually by 1 type, or can use 2 or more types together by arbitrary ratios.

(4) The polyester ether polyol is not particularly limited, but includes, for example, a reaction product obtained by reacting a polyol compound containing an ether group with a polyvalent carboxylic acid or an anhydride thereof. The polyol compound containing an ether group is not particularly limited, and examples thereof include the above-mentioned (2) polyether polyol and diethylene glycol. A polyol compound containing an ether group can be used singly, or two or more of them can be used in combination at any ratio. The polyvalent carboxylic acid or its anhydride is not particularly limited, and includes, for example, the exemplified compounds mentioned in the explanation of (1) Aliphatic polyester polyol. Polyvalent carboxylic acid or its anhydride can be used individually by 1 type, or can use 2 or more types together by arbitrary ratios. Specific examples of polyester ether polyols include polytetramethylene glycol-adipic acid condensates.

(5) The polyethylene terephthalate polyol is not particularly limited, and for example, a known polyethylene terephthalate polyol can be used.

The polyol component can be used singly, or two or more can be used in combination at any ratio.

The polyisocyanate component is not particularly limited, but includes, for example, aliphatic polyisocyanate compounds containing two or more isocyanate groups in one molecule, alicyclic polyisocyanate compounds, and aromatic polyisocyanate compounds.

The aliphatic polyisocyanate compound is not particularly limited, and examples thereof include aliphatic diisocyanates having 1 to 12 carbon atoms such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and hexane diisocyanate (HDI). .

The alicyclic polyisocyanate compound is not particularly limited. A cyclic diisocyanate and the like can be mentioned.

The aromatic polyisocyanate compound is not particularly limited, but examples include aromatic diisocyanates such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate.

The polyisocyanate component can be used alone, or two or more can be used in combination at any ratio.

Among these, the polyurethane itself, the urethane prepolymer and the polyurethane product are preferably polycarbonate-based polyurethanes or polyester-ether-based polyurethanes, respectively. A polycarbonate-based polyurethane is a polyurethane having a carbonate skeleton in the molecular structure of the polyurethane. Examples thereof include polyurethanes produced from polycarbonate polyols and polyisocyanate components. A polyester-ether polyurethane is a polyurethane having an ester bond and an ether bond in its molecular structure. Examples thereof include polyurethanes produced from polyester ether polyols and polyisocyanate components.

The urethane prepolymer may contain hydroxyl groups that remain unreacted after the reaction between the polyol component and the polyisocyanate component. The hydroxyl group can be used as a polar group capable of undergoing a cross-linking reaction with a functional group in the cross-linking agent.

The urethane prepolymer is preferably one that can be crosslinked with a crosslinking agent.

The urethane prepolymer preferably contains a polar group in order to allow reaction with the cross-linking agent. Polar groups are not particularly limited, and examples include methylol groups, carboxy groups, carbonyloxycarbonyl groups, epoxy groups, hydroxy groups, oxy groups, ester groups, silanol groups, silyl groups, amino groups, nitrile groups, sulfo groups, and the like. is mentioned. Among these, a methylol group, a hydroxyl group, a carboxy group and an amino group are preferred, a hydroxyl group or a carboxy group is more preferred, and a carboxy group is even more preferred. The amount of polar groups in the polyurethane is not particularly limited, but is preferably 0.0001 equivalent/1 kg or more, more preferably 0.001 equivalent/1 kg or more. Also, the amount of polar groups in the polyurethane is preferably 1 equivalent/1 kg or less.

Polyurethane itself, isocyanate or its derivatives, alcohol or its derivatives, urethane prepolymers, and raw materials used to produce urethane prepolymers, which are raw materials for urethane resins, may be commercially available products or synthetic products. may Commercially available products are not particularly limited, but for example, water-based emulsions marketed as water-based urethane resins may be used. A water-based urethane resin is a composition containing polyurethane and water, and generally, polyurethane and optionally contained optional components are dispersed in water. The water-based urethane resin is not particularly limited. "Bondic (registered trademark)" series, "Hydran (registered trademark) (WLS201, WLS202, etc.)" series, Bayer's "Impranil" series, Kao Corporation's "Poise (registered trademark)" series, Sanyo "Samprene (registered trademark)" series manufactured by Kasei Kogyo Co., Ltd., "Superflex (registered trademark)" series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., "NEOREZ" series manufactured by Kusumoto Kasei Co., Ltd., Lubrizol Co., Ltd. and the "Sancure" series manufactured by Sancure.

A cross-linking agent may be used to form the urethane resin. The cross-linking agent is not particularly limited, and known ones can be used. Examples thereof include epoxy compounds, carbodiimide compounds, oxazoline compounds, isocyanate compounds and the like. Specific examples thereof include cross-linking agents described in paragraphs "0075" to "0094" of JP-A-2016-79210. The cross-linking agents can be used singly or in combination of two or more at any ratio.

A curing accelerator may be used to form the urethane resin. The curing accelerator is not particularly limited, and known ones can be used. Examples thereof include tertiary amine compounds (excluding compounds having a 2,2,6,6-tetramethylpiperidyl group with a tertiary amine at the 4-position), boron trifluoride complex compounds and the like. A hardening accelerator can be used individually by 1 type, or can use 2 or more types together by arbitrary ratios.

A curing aid may be used to form the urethane resin. The curing aid is not particularly limited, and known ones can be used. For example, quinonedioxime, benzoquinonedioxime, p-nitrosophenol and other oxime/nitroso curing agents; N,Nm-phenylenebismaleimide and other maleimide curing agents; diallyl phthalate, triallyl cyanurate, tri allyl-based curing aids such as allyl isocyanurate; methacrylate-based curing aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; vinyl-based curing aids such as vinyltoluene, ethylvinylbenzene, and divinylbenzene; . Curing aids can be used singly or in combination of two or more at any ratio.

The urethane resin can be used singly or in combination of two or more.

"Acrylic resin" refers to a resin containing a structural unit derived from a (meth)acrylate compound. Although the acrylic resin is not particularly limited, it is preferably an acrylic resin obtained by active energy ray curing, and more preferably an acrylic resin obtained by ultraviolet curing. Acrylic resin obtained by active energy ray curing is cured by irradiating active energy to an active energy ray curable (meth)acrylate compound or a mixture of this compound and a compound copolymerizable with this compound. Obtainable. In addition, the acrylic resin obtained by ultraviolet curing can be obtained by irradiating and curing an ultraviolet curable (meth)acrylate compound or a mixture of this compound and a compound copolymerizable therewith with ultraviolet rays. can.

The curable (meth)acrylate compound constituting the acrylic resin is not particularly limited, and known active energy ray-curable (meth)acrylate compounds that can be used as materials for functional layers used in optical applications, and known active energy ray-curable (meth)acrylate compounds. An ultraviolet curable (meth)acrylate compound and the like can be mentioned. Among these, known compounds that can be used as functional layer materials, particularly hard coat layer materials, are preferred. Examples of such compounds include, but are not particularly limited to, monofunctional (meth)acrylate compounds, polyfunctional (meth)acrylate compounds, combinations thereof, and the like.

The monofunctional (meth)acrylate compound is not particularly limited, and known compounds can be used. Examples thereof include (meth)acrylate, methyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like.

The polyfunctional (meth)acrylate compound is not particularly limited, and known compounds can be used. For example, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, isocyanuric EO-modified triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, di Ethylene oxide adduct of pentaerythritol hexaacrylate, fluorine-substituted H in ethylene oxide of the adduct, pentaerythritol tetraacrylate, ethylene oxide adduct of pentaerythritol tetraacrylate, H of ethylene oxide of the adduct A fluorine-substituted one or the like can be used.

A (meth)acrylate compound having an aromatic ring may also be used as the monofunctional (meth)acrylate compound or the polyfunctional (meth)acrylate compound. By using these compounds, the refractive index of the functional layer can be improved. The (meth)acrylate compound having an aromatic ring is not particularly limited, and examples thereof include benzyl acrylate and monofunctional (meth)acrylate compounds represented by any of the following general formulas (i) to (iv). be done. Among these, benzyl acrylate is more preferred.

In general formulas (i) to (iv) above, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an aromatic ring, and n is 0 to 2. represents a positive number.

The acrylic resin preferably contains urethane acrylate resin. The reason for this is that the adhesion between the substrate, which is the refractive index surface, and the functional layer is good, and peeling at the interface, that is, the difference in refractive index is less likely to occur even in long-term use. A urethane acrylate resin represents an acrylic resin containing a structural unit derived from a urethane (meth)acrylate compound.

The urethane (meth)acrylate compound, which is a curable (meth)acrylate compound, is not particularly limited. and the like. Further, the urethane (meth)acrylate compound may be either an aliphatic urethane (meth)acrylate compound or an aromatic urethane (meth)acrylate compound.

Among curable urethane (meth)acrylate compounds, polyether urethane (meth)acrylate is particularly preferable.

The polyether urethane (meth)acrylate is not particularly limited. Examples thereof include those obtained by reaction.

The polyol (ua1) has a terminal hydroxyl group for forming a urethane bond with the isocyanate compound (ua2). When a bifunctional urethane (meth)acrylate is used, the polyol (ua1) has one hydroxyl group at each end of the skeleton. Furthermore, it is essential that the polyol (ua1) has a polyether polyol skeleton. Among these, from the viewpoint of improving adhesiveness, it is preferable to have polypropylene polyol (polypropylene glycol).

The number average molecular weight of the polypropylene polyol as the polyether polyol (ua1) is preferably 1,000 to 10,000, more preferably 1,500 to 5,000. When the number average molecular weight is within such a range, an adhesive composition having excellent adhesion can be obtained. In addition, a number average molecular weight represents the value measured by the gel permeation chromatography method (GPC method) (polystyrene conversion).

When using a bifunctional polyether urethane (meth)acrylate, the isocyanate compound (ua2) has two isocyanate groups.

A known compound can be used as the isocyanate compound (ua2). Examples include tolylene diisocyanate, hydrogenated polydiisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, and other known diisocyanates. These isocyanate compounds (ua2) may be used alone or in combination of two or more.

The (meth)acrylic acid ester (ua3) having a hydroxyl group has at least one hydroxyl group to form a urethane bond.

Such a (meth)acrylic acid ester (ua3) is not particularly limited, and known compounds can be used without limitation. For example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, butanediol mono(meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, glycidol di(meth)acrylate, and penta Erythritol tri(meth)acrylate may be mentioned. These (meth)acrylic acid esters (ua3) may be used alone or in combination of two or more.

Polyether urethane (meth)acrylate can be produced by appropriately adopting conventionally known methods. As a general production method, the polyether polyol (ua1) and the isocyanate compound (ua2) are heated at 70 to 80° C. and stirred for 4 to 6 hours. Thereafter, a (meth)acrylic acid ester (ua3) having a hydroxyl group is further added, and the mixture is stirred for 4 to 6 hours while heating at 70 to 80° C., thereby synthesizing a polyether urethane (meth)acrylate. At this time, the amount of the polyether polyol (ua1), the isocyanate compound (ua2), and the hydroxyl group-containing (meth)acrylic acid ester (ua3) is not particularly limited. They are preferably 62.0 to 96.9% by mass, 2.5 to 25.2% by mass, and 0.4 to 11.7% by mass, respectively.

Although the number average molecular weight of the polyether urethane (meth)acrylate is not particularly limited, it is preferably from 2,000 to 50,000, more preferably from 3,000 to 15,000. In addition, a number average molecular weight represents the value measured by the gel permeation chromatography method (GPC method) (polystyrene conversion).

The functionality of the urethane (meth)acrylate compound is not particularly limited. For example, it may be less than trifunctional or trifunctional or more. Here, when it is hexafunctional or more, it is particularly suitable for forming a hard coat layer.

A commercially available product or a synthetic product may be used as the curable (meth)acrylate compound. For example, Showa Denko Materials Co., Ltd. Fancryl series FA-511AS, FA-512AS, FA-513AS, FA-BZA, FA-314A, FA-318AS, FA-129AS, FA-P240A, FA-P270A, FA -324A, FA-731A, FA-512M, FA-512MT, FA-513M, FA-711MM, FA-712HM, FA-400M (100), FA-BZM, FA-124M, FA-125M, FA-220M, Examples include FA-321M and FA-023M. In addition, there are no particular restrictions on the commercially available urethane (meth)acrylate compound, which is a curable (meth)acrylate compound. Examples of bifunctional aliphatic urethane (meth)acrylate compounds include EBECRYL (registered trademark) 230, 270, 280, 284, 4683, 4858, 8307, 8402, 8411, 8413, 8804, and 8807 manufactured by Daicel Allnex Co., Ltd. , 9270 and 8800, and KRM7735, KRM8961 and KRM8191. Examples of tri- to tetra-functional aliphatic urethane (meth)acrylate compounds include EBECRYL (registered trademark) 294, 4220, 4513, 4738, 4740, 8311, 9260, 8701, 4265, 4587, and 4666 manufactured by Daicel Allnex Co., Ltd. , 4680, 8210 and 8405, and KRM8667, KRM8296 and KRM8528. Hexafunctional or higher aliphatic urethane (meth)acrylate compounds include, for example, EBECRYL (registered trademark) 1290, 5129 and 8301R manufactured by Daicel Allnex, KRM8200, KRM8200AE, KRM8530, KRM8904, KRM8531BA and KRM8452. . Examples of aromatic urethane (meth)acrylate compounds include EBECRYL (registered trademark) 210 and 220 manufactured by Daicel Allnex.

The curable (meth)acrylate compounds can be used singly or in combination of two or more.

The curable (meth)acrylate compound preferably contains a urethane (meth)acrylate compound, and more preferably contains a polyether urethane (meth)acrylate. The content of the urethane (meth)acrylate compound in the curable (meth)acrylate compound is not particularly limited, but is preferably 40 to 100% by mass with respect to the total mass of the curable (meth)acrylate compound. It is more preferably 50 to 100% by mass. Within these ranges, the refractive index of the functional layer tends to be an appropriate value. As a result, display unevenness is further reduced.

As the curable (meth)acrylate compound, aromatic urethane (meth)acrylate; polyether urethane (meth)acrylate; monofunctional (meth)acrylate compound; or polyether urethane (meth)acrylate and monofunctional (meth)acrylate Combined use with a compound is preferred. Aromatic urethane (meth)acrylate; polyether urethane (meth)acrylate; benzyl (meth)acrylate; or combined use of polyether urethane (meth)acrylate and benzyl (meth)acrylate is more preferred. Aromatic urethane (meth)acrylate; polyether urethane (meth)acrylate and benzyl (meth)acrylate are more preferably used in combination.

A cross-linking agent, a curing agent, or a curing accelerator may be used to form the acrylic resin. These are not particularly limited, and known ones can be used. These can be used individually by 1 type, respectively, or can use 2 or more types together.

As the acrylic resin, acrylic resin, which is a thermoplastic resin, may be used. Examples of acrylic resins, which are thermoplastic resins, include, but are not limited to, (co)polymers containing structural units derived from the above (meth)acrylate compounds. Among these, a (co)polymer containing a structural unit derived from the above monofunctional (meth)acrylate compound is preferred, and polymethyl (meth)acrylate (also known as polymethyl methacrylate, abbreviation: PMMA) is more preferred.

The weight average molecular weight (Mw) of the acrylic resin, which is a thermoplastic resin, is not particularly limited, but is preferably 100,000 to 300,000. Weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

The acrylic resin, which is a thermoplastic resin, can be used alone or in combination of two or more.

In forming the functional layer, it is preferable to use a curable (meth)acrylate compound and an acrylic resin, which is a thermoplastic resin, together. Moreover, it is more preferable to use polyether urethane (meth)acrylate and polymethyl (meth)acrylate together. That is, as the acrylic resin, it is preferable to use a combination of a curable acrylic resin and an acrylic resin that is a thermoplastic resin. Further, it is more preferable to use a (co)polymer containing a structural unit derived from polyether urethane (meth)acrylate together with polymethyl (meth)acrylate. Further, it is more preferable to use a homopolymer composed of structural units derived from polyether urethane (meth)acrylate together with polymethyl (meth)acrylate.

In the formation of the functional layer, when a curable (meth)acrylate compound and an acrylic resin that is a thermoplastic resin are used in combination, the content of the acrylic resin that is a thermoplastic resin is not particularly limited. It is preferably more than 0% by mass and 60% by mass or less, more preferably more than 0% by mass and 50% by mass or less, relative to the total mass of the acrylate compound and the acrylic resin that is the thermoplastic resin. Within these ranges, the refractive index of the functional layer tends to be an appropriate value. As a result, display unevenness is further reduced.

Commercially available products or synthetic products may be used for the acrylic resin and its raw material (meth)acrylate compound.

The acrylic resin may be used alone or in combination of two or more.

The content of the base resin in the functional layer is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass, relative to the total mass of the functional layer. It is more preferable that it is above. If it is the said range, the function of a functional layer will become more favorable. In addition, the content of the base resin in the functional layer is preferably 100% by mass or less, more preferably 99% by mass or less, and 95% by mass or less with respect to the total mass of the functional layer. is more preferred. Within the above range, the amount of components other than the base resin can be increased, making it easier to further improve the effects of the present invention and to impart other desired functions.

The functional layer preferably contains particles. That is, the functional layer preferably contains at least one kind of particles. The particles act to further reduce display unevenness, particularly display unevenness recognized as screen roughness and display unevenness recognized as luminance unevenness. Hereinafter, the particles contained in the functional layer are also simply referred to as "functional layer particles".

As the functional layer particles, the same particles as those described in the base particles can be used. The types of functional layer particles are also the same as those of the base particles.

The functional layer particles are preferably inorganic particles, more preferably silica (silica particles, particulate silica).

Although the average secondary particle size of the functional layer particles is not particularly limited, it is preferably 10 nm or more. If it is the said range, a display nonuniformity will reduce more. Also, the average secondary particle size of the functional layer particles is not particularly limited, but is preferably 300 nm or less. If it is the said range, the transparency of a film will improve more. The average secondary particle diameter of the functional layer particles can be determined by a method of directly measuring the size of the secondary particles from an electron micrograph of the layer (functional layer). Specifically, in this method, the particle image is measured with a transmission electron microscope (TEM) (H-7650 manufactured by Hitachi High-Tech Co., Ltd.), and 100 randomly selected secondary particles equivalent to circles of equal area An average value of the diameters is obtained, and this value is defined as the average secondary particle size.

The functional layer particles can be used singly or in combination of two or more.

Although the content of the functional layer particles in the functional layer is not particularly limited, it is preferably 0.1% by mass or more with respect to the total mass of the functional layer. If it is the said range, adjustment of a refractive index will become easier. Moreover, the content of the functional layer particles in the functional layer is preferably 10% by mass or less with respect to the total mass of the functional layer. If it is the said range, the transparency of a film will improve more.

The functional layer may further contain components other than the components described above as long as the effects of the present invention are not impaired. Examples of other components include, but are not limited to, components used in the field of known optical films and the field of functional layers for known optical applications. Specifically, heat stabilizers, weather stabilizers, leveling agents, surfactants, antioxidants, antistatic agents, slip agents, antiblocking agents, antifog agents, lubricants, dyes, pigments, natural oils, synthetic oils , wax and the like, but are not limited to these.

In one embodiment of the present invention, the thickness of the functional layer is not particularly limited, but is preferably 0.1 μm or more. Within this range, the refractive index can be adjusted more easily while the function of the functional layer can be satisfactorily exhibited. Moreover, the thickness of the functional layer is preferably 50 μm or less. Within this range, it becomes easier to adjust the refractive index while maintaining good transparency of the film.

An optical film containing a cycloolefin resin substrate preferably has a functional layer, and the functional layer preferably contains acrylic resin or urethane resin and particles. In this case, the functional layer preferably contains an acrylic resin, and the acrylic resin preferably contains a urethane acrylate resin.

In one embodiment of the present invention, the refractive index of the optical film containing the cycloolefin resin substrate is not particularly limited, but is preferably 1.500 or more, more preferably 1.505 or more. It is more preferably 510 or more. Also, the refractive index of the optical film containing the cycloolefin resin substrate is preferably 1.535 or less, more preferably 1.525 or less, and even more preferably 1.515 or less. Within these ranges, the refractive index of the optical film containing the cycloolefin resin substrate tends to be a moderate value. As a result, display unevenness is further reduced. It is particularly preferred that the refractive index at the nD:D line (589 nm) at 25° C. satisfies the above range. The refractive index can be measured with a multi-wavelength Abbe refractometer (trade name: DR-M2, manufactured by Atago Co., Ltd.). Details of the measuring method are described in Examples.

The refractive index of the optical film containing the cycloolefin resin substrate can be adjusted according to the refractive index by forming a functional layer having a refractive index different from that of the cycloolefin resin substrate. can change the refractive index of

In addition, the refractive index of an optical film containing a cycloolefin resin substrate can be controlled by the formulation and manufacturing method of the cycloolefin resin substrate, and by the formulation and manufacturing method of the functional layer when it has a functional layer. For example, as a raw material for the cycloolefin resin of the cycloolefin resin base material or as a raw material for the base resin of the functional layer, use of a material having a bulky structure or an increase in its amount, use of a monomer with a low refractive index and its amount increases, the refractive index of optical films containing cycloolefin resin substrates tends to be lower. Further, for example, when a cycloolefin resin substrate is produced by solution casting, the refractive index of the optical film containing the cycloolefin resin substrate tends to be lower than when produced by melt casting. be. Further, for example, when rapid drying is performed in the production of the functional layer, the refractive index of the optical film containing the cycloolefin resin substrate tends to be lower than when slow drying is performed. In these cases, it is presumed that the refractive index of the optical film containing the cycloolefin resin substrate was lowered due to the decrease in the resin density of the cycloolefin resin substrate and the functional layer. To increase the refractive index, the opposite of the above should be done. Further, for example, by adding particles having a refractive index different from that of the cycloolefin resin to the cycloolefin resin substrate, the refractive index of the optical film containing the cycloolefin resin substrate is changed according to the refractive index of the particles. can be made Further, for example, by adding particles having a refractive index different from that of the base resin to the functional layer, the refractive index of the optical film containing the cycloolefin resin substrate can be changed according to the refractive index of the particles. .

However, the direction of controlling the refractive index of the optical film containing the cycloolefin resin substrate is not limited to these methods.

When the optical film containing the cycloolefin resin base material has a functional layer, the refractive index of the functional layer should be 0.002 to 0.002 to 0.002 relative to the refractive index of the base material layer from the viewpoint of optical scattering (display unevenness). 008 low is preferred.

In one embodiment of the present invention, the haze (%) of the optical film containing the cycloolefin resin substrate is not particularly limited, but is preferably 0.20% or more, more preferably 0.50% or more. Preferably, it is more preferably 0.55% or more. Further, the haze (%) of the optical film containing the cycloolefin resin substrate is preferably 1.00% or less, more preferably 0.90% or less, and 0.85% or less. More preferred. Within these ranges, display unevenness is further reduced. Haze can be measured according to JIS K 7136:2000 using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.). Here, among optical films, in the case of a film having a functional layer (cured layer), it is preferable to use the value measured from the functional layer side. Details of the measuring method are described in Examples.

The haze of an optical film containing a cycloolefin resin substrate can be controlled by, for example, the type of particles (particle size, refractive index, etc.), the amount of particles added, and the like. More specifically, for example, by increasing the refractive index of the cycloolefin resin and the particles, or by increasing the amount of particles having a refractive index difference with the cycloolefin resin, the haze of the optical film is reduced. can be increased. In order to reduce the haze of the optical film, the opposite of the above may be performed.

In one embodiment of the present invention, the variable angle luminosity of the optical film containing the cycloolefin resin substrate is not particularly limited, but is preferably 0.7 to 11. Within this range, display unevenness, particularly display unevenness recognized as screen roughness and display unevenness recognized as luminance unevenness, is further reduced. Variable angle luminosity can be measured as follows. Set the sample (optical film) in a goniophotometer (product number GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd., inclination angle within 0.5 degrees), and measure the position on the sample as a reference. , the visible ray is incident on the surface of the sample at an angle of 80 degrees from the normal direction of the sample (i.e., the visible ray is incident on the surface of the sample at a position inclined by 10 degrees to the normal direction with respect to the surface of the sample). The direction of specular reflection of incident light is defined as a reference angle of 0 degrees, and the intensity of reflected light is measured every 0.1 degrees within a range of ±3.0 degrees around the reference angle. At the time of measurement, the scale of the light receiving aperture is adjusted to "6" and the scale of the luminous flux aperture is adjusted to "1". The variable angle luminous intensity is calculated by calculating the integrated value of the light amount obtained at −3.0 degrees to −2.0 degrees centering on the reference angle.

When the film has a slow axis, there are two possible slow axis directions for the position on the sample as a reference for measurement (when the counterclockwise direction is positive, the direction of 0° with respect to the slow axis and +180° directions). Here, when the optical film containing the cycloolefin resin substrate has a slow axis, the variable angle luminous intensity is 80 degrees from the normal direction of the sample (optical film) with respect to either one of the slow axis directions of the sample (optical film). It is more preferable that the value falls within the above range when the oblique visible light is incident on the surface of the sample and measured. In addition, the variable angle luminous intensity is measured when a visible ray inclined 80 degrees from the normal direction of the sample (optical film) with respect to both slow axis directions of the sample (optical film) is incident on the surface of the sample. It is more preferable that both values are within the above range. In addition, with respect to the slow axis direction of the sample (optical film), the counterclockwise rotation is positive, and from 0° to less than +360° along the sample surface, in all directions rotated at intervals of 45° It is particularly preferred that all the values measured by illuminating the surface of the sample with visible light inclined 80 degrees from the line direction fall within the above range.

(Method for producing optical film containing cycloolefin resin substrate)
In one embodiment of the present invention, a method for producing an optical film containing a cycloolefin resin substrate is not particularly limited, and known methods can be used. Examples thereof include a coating method, a solution film forming method, a melt film forming method (melt film forming method), a vapor phase film forming method, and the like, and these may be used in combination.

Although the cycloolefin resin substrate is not particularly limited, it is preferably produced by a melt film-forming method or a solution film-forming method, more preferably by a melt film-forming method. In these production methods, the film may be stretched during or after film formation, if necessary.

The melt film forming method is not particularly limited, but includes, for example, a melt casting method (melt extrusion method), a press molding method, an inflation molding method, an injection molding method, a blow molding method, and a stretch molding method. Among these, a melt casting method, that is, a resin composition containing a cycloolefin resin and optionally other components, is melted by heating and cast onto a substrate, cooled and solidified to form a film. A method of forming is preferred. As for the melt film-forming method, a known method can be appropriately employed. For example, the method described in paragraphs "0111" to "0116" of Japanese Patent No. 5509515, the method described in paragraphs "0224" to "0230" of JP-A-2016-153839, etc., with appropriate modifications. can be employed on However, applicable melt film-forming methods are not limited to these.

In one embodiment of the present invention, it is preferable to dry the pellets before melting in the melt casting method. Although the drying temperature is not particularly limited, it can be, for example, 80 to 120°C. Also, the drying time is not particularly limited, but can be, for example, 2 to 12 hours.

Although the melting temperature in the melt casting method is not particularly limited, it is preferably at least the melting temperature of the cycloolefin resin used, preferably at least 220°C. Moreover, the melting temperature in the melt casting is preferably 350° C. or less from the viewpoint of transparency of the film.

In one embodiment of the present invention, the production equipment used in the melt casting method is not particularly limited, and known production equipment used in the melt casting method can be used. Examples include, but are not limited to, single-screw extruders, polymer pipes, polymer filters, T-dies, casting drums, and the like.

The solution casting method is not particularly limited, but includes, for example, the solution casting method. For example, 1) obtaining a dope containing a cycloolefin resin, other optional ingredients, and a solvent; 2) casting the obtained dope on a metal support and drying; Examples include a method including a step of peeling off from the support to obtain a film-like material, and 3) a step of further drying the peeled film-like material. Note that the method may further include other steps.

Regarding Step 1) A dope is prepared by dissolving a cycloolefin resin and other components that may be added as necessary in a solvent. Mixing with the solvent may be carried out at room temperature, in a heated environment, or in a cooled environment. The heating temperature and cooling temperature are not particularly limited as long as they are temperatures capable of dissolving the cycloolefin resin. The solvent used for the dope contains at least an organic solvent (good solvent) capable of dissolving the cycloolefin resin. Examples of good solvents include chlorinated organic solvents such as methylene chloride; and non-chlorinated organic solvents such as methyl acetate, ethyl acetate, acetone and tetrahydrofuran. Among them, methylene chloride is preferred. The solvent used for the dope may further contain a poor solvent. Examples of poor solvents include straight or branched chain aliphatic alcohols having 1 to 4 carbon atoms. When the ratio of alcohol in the dope becomes high, the film-like material tends to gel and is easily peeled off from the metal support. Linear or branched aliphatic alcohols having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Of these, ethanol is preferred because of its dope stability, relatively low boiling point, and good drying properties. These solvents can be used singly or in combination of two or more at any ratio.

Although the content of the solvent contained in the dope is not particularly limited, it is more preferably 50% by mass or more, more preferably 60% by mass or more, relative to the total mass of the dope. The content of the solvent in the dope is preferably 95% by mass or less, more preferably 85% by mass or less, and particularly preferably 80% by mass or less. The content of the solvent component can be appropriately adjusted from the viewpoint of film production conditions, thickness of the film to be produced, and the like.

It is preferable to perform filtration after preparing the dope.

About the process of 2) The obtained dope is cast on a metal support. Casting of the dope can be performed by discharging from a casting die. The solvent in the dope cast on the metal support is then evaporated and dried. The dried dope is peeled off from the metal support to obtain a film. The residual solvent amount of the dope when peeled from the metal support (residual solvent amount at peeling) is preferably 10 to 150% by mass, more preferably 20 to 40% by mass. The amount of residual solvent in the dope is defined by the following formula. Similarly for:
Amount of residual solvent in dope (% by mass)=(mass of dope before heat treatment−mass of dope after heat treatment)/mass of dope after heat treatment×100
Note that the heat treatment for measuring the amount of residual solvent means heat treatment at 120° C. for 60 minutes.

About the process of 3) The obtained film-like material is further dried. The drying temperature is not particularly limited. )°C, and more preferably (Tg-30)°C to (Tg+50)°C. A specific example of the drying temperature is not particularly limited, but is preferably 100° C. or higher, more preferably 120° C. or higher. The stretching temperature is preferably 220° C. or lower, more preferably 200° C. or lower, and even more preferably 180° C. or lower. The amount of residual solvent in the film-like material at the start of drying is preferably 2 to 50% by mass.

It is preferable to dry the film while transporting it. The film-like material may be stretched at the same time as drying. The stretching method and stretching conditions are the same as those described later for the stretching treatment in the production of the optical film containing the cycloolefin resin substrate. In the solution casting method, when the film is stretched at the same time as the drying, the film is stretched in the MD direction (conveyance direction), for example, by giving a plurality of rolls different circumferential speeds, and the rolls having different circumferential speeds between them. It is preferable to carry out by the method to be used (roll method). Stretching of the film in the TD direction (a method perpendicular to the conveying direction) can be performed, for example, by fixing both ends of the film with clips or pins and widening the distance between the clips or pins in the traveling direction (tenter method). is preferred.

In one embodiment of the present invention, when the optical film has a functional layer in addition to the above cycloolefin resin substrate, the method for producing the optical film containing the cycloolefin resin substrate comprises the cycloolefin resin substrate or the The method preferably includes a step of forming a functional layer on the raw film.

The "raw film of the cycloolefin resin substrate" refers to the film of the cycloolefin resin substrate obtained after stretching under specific conditions, before the stretching. The original film may be already stretched as long as it is further stretched thereafter.

It is preferable that the surface of the cycloolefin resin substrate or raw film thereof on which the functional layer is to be formed is subjected to a surface modification treatment in order to improve the adhesion between the cycloolefin resin substrate and the functional layer. . The surface modification treatment is not particularly limited, and known surface modification treatments can be used. Examples include active energy ray irradiation treatment and chemical treatment. Examples of the active energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment and the like. The chemical treatment includes, for example, a saponification treatment, a treatment in which the film is immersed in an oxidizing agent aqueous solution such as a potassium dichromate solution and concentrated sulfuric acid, and then washed with water. As these surface modification treatment methods, the methods described in paragraphs "0125" to "0139" of Japanese Patent Laid-Open No. 2016-79210 can be employed with appropriate modifications as necessary. However, applicable surface modification treatment methods are not limited to these. Among these, active energy ray irradiation treatment is preferable, corona discharge treatment or plasma treatment is more preferable, and corona discharge treatment is still more preferable, from the viewpoint of treatment efficiency. These surface modification treatments can be used singly or in combination of two or more.

Although the output of the corona discharge treatment is not particularly limited, it is preferably 0.02 kW or more, more preferably 0.04 kW or more. The output of the corona discharge treatment is preferably 5 kW or less, more preferably 2 kW or less. Moreover, the electrode length used for corona discharge treatment is not particularly limited. And it is preferable to carry out the corona discharge treatment while transporting. The conveying speed for corona discharge treatment is not particularly limited.

Although the corona discharge treatment device (corona treatment device) is not particularly limited, for example, a known device can be used.

Although the method for forming the functional layer is not particularly limited, it is preferably formed by a coating method. The coating method is not particularly limited, and known methods can be used. Examples thereof include wire bar coating, dipping, spraying, spin coating, roll coating, gravure coating, air knife coating, curtain coating, slide coating, extrusion coating and die coating.

The coating liquid for forming the functional layer may further contain a solvent in addition to the base resin that may be added as required and other components that may be added as required. As a solvent, for example, water or an organic solvent can be used. Examples of organic solvents include, but are not limited to, methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethylsulfoxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, dichloromethane, methyl ethyl ketone, cyclohexanone, and the like. . Water or an organic solvent can be used singly, or two or more of them can be used in combination at any ratio.

The solid content concentration of the functional layer-forming coating liquid is not particularly limited, but is preferably 0.5% by mass or more, and preferably 1% by mass or more, relative to the total mass of the functional layer-forming coating liquid. more preferred. The solid content concentration of the functional layer-forming coating liquid is preferably 15% by mass or less, more preferably 10% by mass or less, relative to the total mass of the functional layer-forming coating liquid. Within these ranges, the handleability and coating properties of the coating liquid are further improved.

When the functional layer is formed by a coating method, the method for producing an optical film containing a cycloolefin resin substrate comprises coating a functional layer forming coating liquid on at least one surface of the cycloolefin resin substrate or the original film thereof. and forming a layer of the functional layer coating liquid. The step preferably includes drying the solvent contained in the coating liquid for forming the functional layer. When the functional layer is a hardened layer, it is preferable to dry the solvent contained in the coating liquid and allow the hardening reaction to proceed. Also, at this time, drying and curing may proceed at the same time. At this time, in addition to drying and curing, stretching, which will be described later, may proceed at the same time. In addition, it is preferable to heat when drying, curing, or stretching the coating liquid for forming the functional layer.

The heating temperature and heating time can be appropriately set within a range in which the desired treatment and reaction can proceed. Although the heating temperature is not particularly limited, it is preferably 40 to 150°C, more preferably 60 to 130°C. The heating time is not particularly limited as long as the desired drying or effect is possible.

The drying conditions for the functional layer are not particularly limited, but from the viewpoint of controlling the refractive index, if it is desired to increase the refractive index, it is preferable to perform slow drying, which is drying at a low drying speed, to decrease the refractive index. If desired, it is preferable to perform rapid drying, which is drying at a high drying speed. As used herein, “slow drying” means drying at a drying rate of 0.2 g/m ² ·s or less. Also, "rapid drying" means drying at a drying speed of 0.8 to 4.8 g/m ² ·s.

The drying speed is calculated by measuring the film thickness of the coating liquid on the transported support and calculating the volatilization amount of the solvent in the coating liquid from the change in the film thickness (specifically, the formula: {film Thickness change [μm]×specific gravity [−]}/Time required for film thickness change (s), 1 μm thickness is equivalent to 1 g/m ² at a density of 1000 kg/m ³ ), volatilization of solvent per unit area per unit time It can be obtained by calculating the amount (g/m ² ·s) and using this value as the drying speed.

Drying is not particularly limited, but can be performed using dry air, an electric heater, an infrared heater, a heating roll, or the like. Among these, dry air is preferred. In addition, although the drying equipment is not particularly limited, it is preferable to have an air supply hole for supplying and exhausting dry air and an exhaust hole.

When the functional layer is a cured layer, it is preferable to cure the functional layer by irradiation with active energy rays. The active energy ray is not particularly limited, but ultraviolet rays are preferable. The output of the ultraviolet irradiation device is not particularly limited, but can be, for example, 100 to 300W. Moreover, the irradiation amount of ultraviolet rays is not particularly limited. For example, it can be 100 to 2000 mJ/cm ² . The ultraviolet irradiation device is not particularly limited, and a known device can be used. For example, an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) and the like can be mentioned. The irradiation environment for active energy ray irradiation (preferably ultraviolet irradiation) is not particularly limited, but it is preferably performed under an inert gas purge such as nitrogen, and more preferably under a nitrogen purge.

In the production of an optical film containing a cycloolefin resin substrate, it is preferable to provide a step of stretching the original film to obtain the cycloolefin resin substrate. The raw film may be stretched in a single state, or may be stretched in a state where a functional layer-forming coating liquid layer or a functional layer is formed on the raw film.

As a preferred embodiment of the method for producing an optical film containing a cycloolefin resin substrate, (A): (A-1) a layer of a coating liquid for forming a functional layer is formed on at least one raw film of a cycloolefin resin substrate. (A-2) stretching the raw film to obtain a cycloolefin resin base material; (A-3) drying the layer of the coating liquid, (if necessary Further curing as necessary to obtain a functional layer (for example, a cured layer). Either the above step (A-2) or the above step (A-3) may be performed first, or both steps may be performed simultaneously.

Further, as another preferred embodiment of the method for producing an optical film containing a cycloolefin resin substrate, (B): (B-1) a step of stretching a raw film to obtain a cycloolefin resin substrate; , (B-2) forming a layer of the coating liquid for forming the functional layer on at least one surface of the cycloolefin resin substrate; and (B-3) drying the layer of the coating liquid, (if necessary and a step of obtaining a functional layer (for example, a cured layer) by further curing with a heat source.

In the production of an optical film containing a cycloolefin resin base material, when stretching is performed, the stretching method is not particularly limited. For example, a method of uniaxially stretching in the longitudinal direction using a difference in peripheral speed between rolls (longitudinal uniaxial stretching); a method of uniaxially stretching in the width direction using a tenter (horizontal uniaxial stretching); longitudinal uniaxial stretching and lateral uniaxial stretching. and in order (sequential biaxial stretching); a method of simultaneously performing longitudinal stretching and transverse stretching (simultaneous biaxial stretching); a method of stretching in an oblique direction with respect to the longitudinal direction of the film before stretching (diagonal stretching); mentioned. As used herein, "diagonal" means a direction that is neither parallel nor perpendicular.

In the production of an optical film containing a cycloolefin resin base material, when stretching is performed, the stretching ratio is not particularly limited, but is preferably 1.01 times or more, more preferably 1.5 times or more. It is preferably 1.7 times or more, more preferably 2.0 times or more. The draw ratio is preferably 10.0 times or less, more preferably 7.0 times or less, and even more preferably 5.0 times or less. When stretching the film while drying, the stretching ratio is not particularly limited, but is preferably 1.01 times or more, more preferably 1.1 times or more, and 1.2 times. It is more preferable that it is above. In this case, the draw ratio is preferably 1.5 times or less, more preferably 1.4 times or less, and even more preferably 1.3 times or less. Here, when stretching is performed in two or more steps, the product of the draw ratios in each step is preferably within the above range.

In the production of an optical film containing a cycloolefin resin base material, when stretching is performed, the stretching temperature is not particularly limited, but is preferably 100°C or higher, more preferably 120°C or higher. The stretching temperature is preferably 220° C. or lower, more preferably 200° C. or lower, and even more preferably 180° C. or lower. When drying, curing, and stretching are performed simultaneously, the stretching temperature is preferably 150° C. or lower, more preferably 130° C. or lower.

From the viewpoint of increasing the production efficiency of an optical film containing a cycloolefin resin substrate, it is preferable to produce the optical film as a long film.

(Other optical films)
In at least one of the polarizing plates included in the display device according to an embodiment of the present invention, when an optical film containing a base material containing a cycloolefin resin is arranged only on one surface of the polarizer, Another optical film may be placed on the other side of the polarizer.

In addition, in the display device according to one embodiment of the present invention, when a polarizing plate that does not have an optical film containing a substrate containing a cycloolefin resin is further used, one or both surfaces of the polarizing plate have , other optical films may be placed. Other optical films are not particularly limited, and known optical films can be used.

The other optical film preferably contains a resin film. Examples of resin films include, but are not limited to, cellulose ester films, acrylic films, and polycarbonate films. Among these, a cellulose ester film is preferred. Commercially available cellulose ester films include, but are not limited to, Konica Minolta Tack KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY- HA, KC2UA, KC4UA, KC6UAKC, 2UAH, KC4UAH, KC6UAH (manufactured by Konica Minolta Co., Ltd.) and FUJITAC (registered trademark) T40UZ, T60UZ, T80UZ, TD80UL, TD60UL, TD40UL, R02, R06 (Fuji Film Co., Ltd.) and the like.

Although the thickness of the resin film is not particularly limited, it is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. Within these ranges, the protective function of the polarizer is further improved. Although the thickness of the resin film is not particularly limited, it is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 60 μm or less. Within these ranges, the thickness of the polarizing plate can be further reduced.

Other optical films may further include a functional layer in addition to the above resin film. The functional layer is not particularly limited, and includes functional layers used in optical applications.

(Polarizer)
A polarizing plate included in a display device according to an embodiment of the present invention includes a polarizer. A polarizer is an element that passes only light with a plane of polarization in a certain direction.

A known polarizer can be used without particular limitation, but a polyvinyl alcohol-based polarizing film is preferred. The polyvinyl alcohol-based polarizing film may be a polyvinyl alcohol-based film dyed with iodine, or may be a polyvinyl alcohol-based film dyed with a dichroic dye. For example, the polyvinyl alcohol-based polarizing film includes a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to durability treatment with a boron compound). Further, for example, as a polyvinyl alcohol polarizing film, a polyvinyl alcohol film is dyed with iodine or a dichroic dye and then uniaxially stretched (preferably, a film further subjected to durability treatment with a boron compound). mentioned. Among these, a film obtained by dyeing a polyvinyl alcohol-based film with iodine, applying a durability treatment with a boron compound, and then uniaxially stretching the film is particularly preferable. The absorption axis of a polarizer is usually parallel to the direction of maximum stretch.

The polyvinyl alcohol-based film used for forming the polyvinyl alcohol-based polarizing film is not particularly limited. Examples include ethylene-modified polyvinyl alcohol having a degree of polymerization of 1 to 4 mol%, a degree of polymerization of 2000 to 4000, and a degree of saponification of 99.0 to 99.99 mol%.

Although the temperature during uniaxial stretching is not particularly limited, it is preferably 30 to 90°C. Although the ratio of uniaxial stretching is not particularly limited, it is preferably 1.05 to 10 times, more preferably 2 to 8 times, and even more preferably 4 to 6 times.

Although the thickness of the polarizer is not particularly limited, it is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 5 μm or more. Within these ranges, the polarization performance is further improved. Also, the thickness of the polarizer is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. Within these ranges, the thickness of the polarizing plate can be further reduced.

Although the refractive index of the polarizer is not particularly limited, it is preferably 1.500 to 1.520.

A polarizing plate included in a display device according to an embodiment of the present invention has an optical film containing a cycloolefin resin base material, and the refractive index difference between the optical film containing the cycloolefin resin base material and the polarizer is as follows. satisfies equation (1):
Formula (1) 0≦(refractive index of optical film−refractive index of polarizer)<0.02
When the refractive index difference between the optical film of formula (1) (the optical film containing the cycloolefin resin base material) and the polarizer is less than 0, display unevenness, particularly display unevenness recognized as luminance unevenness, increases. do. Further, when the difference in refractive index between the optical film of formula (1) (the optical film containing the cycloolefin resin base material) and the polarizer is 0.02 or more, display unevenness, particularly screen roughness, is recognized. display unevenness increases.

Further, in the polarizing plate included in the display device according to one embodiment of the present invention, the difference in refractive index between the optical film containing the cycloolefin resin base material and the polarizer preferably satisfies the following formula (2):
Formula (2) 0.001 ≤ (refractive index of optical film - refractive index of polarizer) ≤ 0.015
Within this range, display unevenness is further reduced. From the same point of view, the upper limit of the refractive index difference between the optical film containing the cycloolefin resin substrate and the polarizer is more preferably 0.008 or less, and even more preferably 0.005 or less.

In the display device according to one embodiment of the present invention, in at least one polarizing plate included therein, the refractive index difference between the optical film containing at least one cycloolefin resin base material and the polarizer is expressed by the above formula (1) It suffices if the relationship of Further, in the polarizing plate including at least a polarizer having an absorption axis that serves as a reference for the angle along the display surface in the measurement of the RMS granularity of the display device, an optical film including at least one cycloolefin resin substrate; It is preferable that the refractive index difference from the polarizer satisfies the relationship of the above formula (1). and an optical film containing at least one cycloolefin resin substrate in the viewer-side polarizing plate containing a polarizer having an absorption axis that serves as a reference for the angle along the display surface in the measurement of the RMS granularity of the display device; , the refractive index difference with the polarizer preferably satisfies the relationship of the above formula (1). In these cases, it is preferable that the refractive index difference between the optical film containing at least one cycloolefin resin substrate and the polarizer satisfies the relationship of the above formula (2). In this case, the upper limit of the refractive index difference between the optical film containing at least one cycloolefin resin substrate and the polarizer is more preferably 0.008 or less, more preferably 0.005 or less. More preferred.

Here, in the display device according to one embodiment of the present invention, in all of the polarizing plates included therein, the difference in refractive index between the optical film containing at least one cycloolefin resin base material and the polarizer is the above formula ( 1) is preferably satisfied. In this case, it is more preferable that the refractive index difference between the optical film containing at least one cycloolefin resin substrate and the polarizer satisfies the above formula (2). In this case, the upper limit of the refractive index difference between the optical film containing at least one cycloolefin resin substrate and the polarizer is more preferably 0.008 or less, more preferably 0.005 or less. More preferred.

Then, in the display device according to one embodiment of the present invention, in all of the polarizing plates included therein, the difference in refractive index between the optical film containing all the cycloolefin resin substrates and the polarizer is expressed by the above formula (1) is preferably satisfied. At this time, it is more preferable that the refractive index difference between the optical film containing all the cycloolefin resin substrates and the polarizer satisfies the above formula (2). In this case, the upper limit of the refractive index difference between the optical film containing all the cycloolefin resin substrates and the polarizer is more preferably 0.008 or less, more preferably 0.005 or less. preferable.

Furthermore, in a display device according to an embodiment of the present invention, all the polarizing plates included therein have only one optical film containing a cycloolefin resin base material, and the cycloolefin resin base material is The refractive index difference between the optical film containing and the polarizer preferably satisfies the above formula (1). In this case, it is more preferable that the refractive index difference between the optical film containing the cycloolefin resin base material and the polarizer satisfies the above formula (2). In this case, the upper limit of the refractive index difference between the optical film containing the cycloolefin resin base material and the polarizer is more preferably 0.008 or less, and further preferably 0.005 or less. .

When the refractive index difference between the optical film containing the cycloolefin resin base material and the polarizer satisfies the range of the above formula (2), or when the refractive index difference between the optical film containing the cycloolefin resin base material and the polarizer When the upper limit is 0.008 or less or 0.005 or less, the optical film containing the cycloolefin resin base material has a functional layer, and the functional layer contains an acrylic resin or a urethane resin and particles. preferably.

It is particularly preferred that the refractive index at the nD:D line (589 nm) at 25°C satisfies each of the above ranges. The refractive index of the optical film containing the cycloolefin resin substrate and the refractive index of the polarizer can be measured with a multi-wavelength Abbe refractometer (trade name: DR-M2, manufactured by Atago Co., Ltd.). The details of the measuring method are as described in Examples.

(Manufacturing method of polarizing plate)
A method for manufacturing the polarizing plate included in the display device according to one embodiment of the present invention is not particularly limited, and a known method can be used. For example, a polarizing plate can be produced by laminating a polarizer and an optical film containing the cycloolefin resin substrate and/or other optical film via an adhesive (i.e., via an adhesive layer). can be manufactured.

The adhesive is not particularly limited, and known ones can be used. Examples thereof include a completely saponified polyvinyl alcohol aqueous solution (water glue) and an active energy ray-curable adhesive. Among these, the polarizer and the optical film and/or other optical film containing the above cycloolefin resin base material are considered to be easy to obtain a polarizing plate having high strength and excellent flatness even in a thin film. , and is preferably bonded with an active energy ray-curable adhesive.

Although the active energy ray-curable adhesive is not particularly limited, for example, a photo-radical polymerizable composition using photo-radical polymerization, a photo-cationic polymerizable composition using photo-cationic polymerization, and photo-radical polymerization and photo-cation A hybrid type composition that uses polymerization in combination and the like can be mentioned.

The photoradical polymerizable composition is not particularly limited. For example, a known radical photopolymerizable composition can be used. In particular, the radically polymerizable compound contained in the radically photopolymerizable composition is not particularly limited, but is preferably a compound having a radically polymerizable ethylenically unsaturated bond. The compound having a radically polymerizable ethylenically unsaturated bond is not particularly limited, but a compound having a (meth)acryloyl group is preferred. Although the compound having a (meth)acryloyl group is not particularly limited, examples thereof include N-substituted (meth)acrylamide compounds and (meth)acrylate compounds. The photoradical polymerizable composition is not particularly limited, but for example, a radically polymerizable compound containing a polar group such as a hydroxy group or a carboxyl group and a radical polymerization containing no polar group described in JP-A-2008-009329. and a composition containing a specific proportion of a chemical compound.

The photo cationic polymerizable composition is not particularly limited. For example, a known cationic photopolymerizable composition can be used. The cationic polymerizable compound contained in the cationic photopolymerizable composition is not particularly limited, and examples thereof include a curable compound having an epoxy group and a curable compound having an oxetanyl group. The photocationically polymerizable composition is not particularly limited, but for example, (α) a cationic polymerizable compound and (β) a photocationic polymerization initiator, as described in JP-A-2011-028234. , (γ) a photosensitizer exhibiting maximum absorption at a wavelength longer than 380 nm, and (δ) a naphthalene-based photosensitizing aid.

Preferred examples of active energy ray-curable adhesives include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate and Epolead (registered trademark) GT-301 (an alicyclic epoxy resin manufactured by Daicel Corporation). ), 1,4-butanediol diglycidyl ether, triarylsulfonium hexafluorophosphate, 9,10-dibutoxyanthracene, and 1,4-diethoxynaphthalene.

A method for producing a polarizing plate using an active energy ray-curable adhesive is not particularly limited, but for example, 1) an active energy ray-curable adhesive is applied to at least one of the adhesive surfaces of the polarizer and the optical film. 2) bonding the polarizer and the optical film together via the obtained adhesive layer; and 3) in a state where the polarizer and the optical film are bonded together via the adhesive layer. Examples include a production method including a step of irradiating with an energy beam to cure the adhesive layer to obtain a polarizing plate, and 4) a step of punching (cutting) the obtained polarizing plate into a predetermined shape. Before step 1), if necessary, a step 5) of subjecting the surface of the optical film to which the polarizer is to be adhered to easy-adhesion treatment (for example, corona discharge treatment, plasma treatment, etc.) may be further included.

In the application of the active energy ray-curable adhesive in step 1), the desired thickness of the adhesive layer after curing is not particularly limited. However, the application of the active energy ray-curable adhesive is preferably carried out so that the thickness of the adhesive layer after curing is 0.01 μm or more, more preferably 0.1 μm or more, and 0.1 μm or more. 0.5 μm or more is more preferable. Adhesiveness improves more that it is these ranges. In addition, the application of the active energy ray-curable adhesive is preferably performed so that the thickness of the adhesive layer after curing is 10 μm or less, more preferably 5 μm or less, and 3 μm or less. is more preferred. Within these ranges, the thickness of the polarizing plate can be further reduced.

In the step 3), the active energy rays to be irradiated are not particularly limited, and examples thereof include visible light, ultraviolet rays, X-rays and electron beams. In general, it is preferable to use ultraviolet light because it is easy to handle and has a sufficient curing speed. The irradiation conditions of the ultraviolet rays may be any conditions as long as the adhesive can be cured. For example, the irradiation amount of ultraviolet rays is preferably 50 to 1500 mJ/cm ² in terms of integrated light amount, and more preferably 100 to 1000 mJ/cm ² . It is preferable to carry out the ultraviolet irradiation while transporting. Although the ultraviolet irradiation device is not particularly limited, for example, a known device can be used.

In step 5), corona discharge treatment is preferable as the easy-adhesion treatment. However, surface modification treatment can be used individually by 1 type, or can use 2 or more types together. The output of the corona discharge treatment is not particularly limited, but is preferably 0.02 kW or more, more preferably 0.04 kW or more. The output of the corona discharge treatment is preferably 5 kW or less, more preferably 2 kW or less. Moreover, it is preferable to carry out the corona discharge treatment while transporting. The conveying speed for corona discharge treatment is not particularly limited. A corona discharge treatment device (corona treatment device) is not particularly limited, and for example, a known device can be used.

In addition, it can be said that the effect of the present invention is exhibited by applying the polarizing plate according to the present description to a display device unit. From this, another aspect of the present invention is a polarizing plate having a polarizer and an optical film, wherein the optical film has at least a base material, the base material contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1),
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity (RMS granularity of the display device) of a display image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is It can also be said that it relates to the polarizing plate, which is 0.30 to 1.34. A preferred embodiment of the present invention is a polarizing plate having a polarizer and an optical film, wherein the optical film has at least a substrate, the substrate contains at least a cycloolefin resin, and the optical film and the refractive index difference between the polarizer satisfies the following formula (1),
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity (RMS granularity of the display device) of a display image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is It can also be said that it relates to the polarizing plate, which is 0.30 to 1.30.

The details and preferred aspects of the polarizing plate according to this aspect and the optical film containing the cycloolefin resin base material contained therein are, respectively, in the polarizing plate included in the display device according to one aspect of the present invention, Similar to these descriptions. In addition, the details and preferred aspects of the display device in which the polarizing plate according to this aspect is incorporated and the display device unit combined with the display device are the same as those described below for the display device according to one aspect of the present invention.

The polarizing plate according to one embodiment of the present invention is preferably incorporated on the viewing side of the display cell of the display device unit. Further, it is more preferable that the polarizing plate according to one embodiment of the present invention is incorporated in the viewing side of the display cell of the display device unit and on the side opposite to the viewing side. At this time, the absorption axis of the polarizer of the polarizing plate incorporated on the viewing side of the display cell and the absorption axis of the polarizer of the polarizing plate incorporated on the side opposite to the viewing side of the display cell are perpendicular to each other (that is, crossed Nicols ) is preferred.

[Display unit]
A display device according to an embodiment of the present invention includes a display device unit. In the present specification, the display device unit is a member required for display of the display device or an assembly thereof, other than the polarizing plate described above. The display unit preferably includes a display cell.

Although the display device according to one embodiment of the present invention is not particularly limited, it is preferably a liquid crystal display device or an organic electroluminescence (organic EL) display device, and more preferably a liquid crystal display device. That is, in the display device according to one embodiment of the present invention, the display device unit preferably includes a display cell, and the display cell is a liquid crystal cell or an organic EL cell.

In one embodiment of the present invention, when the display device is a liquid crystal display device, the display device unit is not particularly limited, but preferably includes a liquid crystal cell as a display cell and a backlight as a light source. The liquid crystal cell and the backlight are not particularly limited, and for example, known ones can be used. Moreover, in one embodiment of the present invention, when the display device is an organic EL display device, the display device unit includes at least an organic EL cell which is a display cell. The organic EL cell is not particularly limited, and for example, known cells can be used. The display device unit may further include a housing, a touch panel, etc., as required. These are also not particularly limited, and for example, known ones can be used.

[Configuration example of preferable display device]
As a preferred embodiment of the present invention, for example, a liquid crystal cell, a first polarizing plate arranged on one surface of the liquid crystal cell, and a second polarizing plate arranged on the other surface of the liquid crystal cell are provided. and a liquid crystal display device containing the liquid crystal display. Here, at least one of the first polarizing plate and the second polarizing plate is a polarizing plate containing the optical film containing the above cycloolefin resin base material. Both the first polarizing plate and the second polarizing plate are preferably polarizing plates containing an optical film containing the above cycloolefin resin base material. In this case, in each of the first polarizing plate and the second polarizing plate, it is more preferable that the optical film containing the cycloolefin resin base material is arranged on the surface of the polarizer on the liquid crystal cell side. Further, it is more preferable that the optical film containing the above cycloolefin resin substrate has the above functional layer in addition to the cycloolefin resin substrate. In this case, it is particularly preferable that an easy-adhesion layer is included as the functional layer, and the easy-adhesion layer is arranged on the polarizer-side surface of the cycloolefin resin base material. Further, in each of the first polarizing plate and the second polarizing plate, it is more preferable that another optical film is arranged on the surface of the polarizer opposite to the liquid crystal cell. Also, the display device unit includes at least a liquid crystal cell. More preferably, the display unit further includes a backlight.

The absorption axis of the polarizer of the first polarizing plate and the absorption axis of the polarizer of the second polarizing plate are preferably orthogonal (that is, crossed Nicols).

The method of bonding the liquid crystal display device and the polarizing plate is not particularly limited, but they are preferably bonded via an adhesive or pressure-sensitive adhesive (that is, via an adhesive layer or pressure-sensitive adhesive layer), It is more preferable to laminate via an adhesive. The adhesive is not particularly limited, and known ones can be used. For example, the adhesive described in the method for manufacturing the polarizing plate can be used. The adhesive is not particularly limited, and known ones can be used. For example, acrylic pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and the like can be used.

The display mode of the liquid crystal cell is not particularly limited. continuous spin wheel alignment (CPA) mode, hybrid alignment nematic (HAN) mode, twisted nematic (TN) mode, super twisted nematic (STN) mode, optically compensated bend (OCB) mode, etc. be able to. Among these, the VA mode is preferable from the viewpoint that the effects of the present invention are exhibited more satisfactorily. Therefore, in one preferred embodiment of the present invention, it is preferred that the display unit is a vertically aligned (VA) liquid crystal display unit (ie, a display unit including a vertically aligned (VA) mode liquid crystal cell).

An example of a liquid crystal display device according to a preferred embodiment of the present invention will be described below. However, the display device according to the present invention is not limited to the one described below.

FIG. 3 is a schematic diagram showing an example of the basic configuration of a liquid crystal display device according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing another example of the basic configuration of the liquid crystal display device according to one embodiment of the present invention. As shown in FIGS. 3 and 4, the liquid crystal display device 10 according to one embodiment of the present invention includes a liquid crystal cell 30, a first polarizing plate 50 arranged on one surface of the liquid crystal cell 30, and a liquid crystal It includes a second polarizer 70 disposed on the other side of cell 30 and a backlight 90 . Here, the display device unit includes a liquid crystal cell 30 and a backlight 90 .

The display mode of the liquid crystal cell 30 is not particularly limited, and various display modes as described above can be exemplified. Among these, the VA mode is preferable.

The first polarizing plate 50 consists of a first polarizer 51 arranged on one surface of the liquid crystal cell 30 (on the viewing side surface) and a surface of the first polarizer 51 opposite to the liquid crystal cell 30 ( and an optical film 55 (F2) disposed on the surface of the first polarizer 51 on the liquid crystal cell 30 side.

The second polarizing plate 70 is arranged on the second polarizer 71 arranged on the other surface of the liquid crystal cell 30 (on the surface on the backlight 90 side) and on the surface of the second polarizer 71 on the liquid crystal cell 30 side. and an optical film 75 (F4) disposed on the surface of the second polarizer 71 opposite to the liquid crystal cell 30 (on the surface on the backlight 90 side).

In the first polarizing plate 50 and the second polarizing plate 70, each optical film can also be said to be a protective film for protecting the polarizer. Moreover, it is preferable that the absorption axis of the first polarizer 51 and the absorption axis of the second polarizer 71 are orthogonal (that is, crossed Nicols).

At least one of the optical films 53 (F1), 55 (F2), 73 (F3) and 75 (F4) is an optical film containing the above cycloolefin resin base material. Among these, the optical films 55 (F2) and 73 (F3) are preferably optical films containing the above cycloolefin resin base material. Further, in this case, it is more preferable that each of the optical films 55 (F2) and 73 (F3) further has the above functional layer in addition to the cycloolefin resin base material.

The optical films 53 (F1) and 75 (F4) are preferably optical films other than optical films containing cycloolefin resin substrates, and are particularly preferably cellulose ester films.

As shown in FIG. 4, the optical films 55 (F2) and 73 (F3) more preferably have the

functional layers

552 and 732 described above in addition to the

cycloolefin resin substrates

551 and 731, respectively. At this time, in the first polarizing plate 50, the functional layer 552 may be arranged on either surface of the cycloolefin resin substrate 551, or may be arranged on both surfaces. It is particularly preferable to be arranged on the surface of the substrate 551 on the side of the first polarizer 51 . In the second polarizing plate 70, the optical film 73 (F3) and the functional layer 732 may be arranged on either surface of the cycloolefin resin base material 731, and may be arranged on both surfaces. However, it is particularly preferable to arrange it on the surface of the cycloolefin resin base material 731 on the side of the second polarizer 71 .

The present invention includes, but is not limited to, the following aspects and forms:
[1] In a display device having a polarizing plate and a display device unit,
The polarizing plate has a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
A display device, wherein the RMS granularity of a display image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.34;
[2] The display device according to [1], wherein the RMS granularity is 0.30 to 1.30;
[3] The display device according to [1] or [2], wherein the optical film further has a functional layer;
[4] The refractive index difference between the optical film and the polarizer satisfies the following formula (2),
Formula (2) 0.001≦(refractive index of the optical film−refractive index of the polarizer)≦0.015
The display device according to [3], wherein the functional layer contains an acrylic resin or a urethane resin, and particles;
[5] The display device according to [3] or [4], wherein the functional layer contains an acrylic resin, and the acrylic resin contains a urethane acrylate resin;
[6] The display device according to any one of [1] to [5], wherein the display device unit is a vertical alignment (VA) liquid crystal display device unit;
[7] The display device according to any one of [1] to [6], wherein at least one of the polarizing plates is arranged on the viewing side of the display cell of the display device unit. ;
[8] A polarizing plate having a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity of the displayed image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.34. A polarizing plate, characterized by having;
[9] The polarizing plate of [8], wherein the RMS granularity is 0.30 to 1.30;
[10] The polarizing plate of [8] or [9], wherein the optical film further comprises a functional layer;
[11] The refractive index difference between the optical film and the polarizer satisfies the following formula (2),
Formula (2) 0.001≦(refractive index of the optical film−refractive index of the polarizer)≦0.015
The polarizing plate of [10], wherein the functional layer contains an acrylic resin or a urethane resin, and particles;
[12] The polarizing plate of [10] or [11], wherein the functional layer contains an acrylic resin, and the acrylic resin contains a urethane acrylate resin;
[13] The display device according to any one of [8] to [12], wherein the display device has a display device unit, and the display device unit is a vertical alignment (VA) liquid crystal display device unit. Polarizer;
[14] The polarizing plate according to any one of [8] to [13], wherein the display device has a display device unit, and the display device unit is incorporated on the viewing side of the display cell.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, "parts" or "%" are used, but "mass parts" or "mass%" are indicated unless otherwise specified.

<Manufacture of optical film>
(Production of cycloolefin resin a1)
Ring-opening polymerization In a nitrogen-substituted reactor, tricyclo[4.3.0.1 ^2,5 ]dec-3-ene (hereinafter also referred to as “DCP”), tetracyclo[4.4.0.1 ^{2 , 5} . 1 ^7,10 ]dodeca-3-ene (hereinafter also referred to as “TCD”), 1,3-dimethyldodecahydrocyclopenta[a]indene (hereinafter also referred to as “MTHF”), and 2-hydroxyethyl acrylate (hereinafter also referred to as "HEA") mixture (mass ratio 18/18/4/60) 7 parts (1% by mass based on the total amount of monomers used for polymerization) and 1600 parts of cyclohexane In addition, 0.55 parts of tri-iso-butylaluminum, 0.21 parts of isobutyl alcohol, 0.84 parts of diisopropyl ether as a reaction modifier, and 3.24 parts of 1-hexene as a molecular weight modifier were added.

To this, 24.1 parts of a 0.65% concentration tungsten hexachloride solution dissolved in cyclohexane was added and stirred at 55°C for 10 minutes.

Then, while maintaining the reaction system at 55° C., 693 parts of a mixture of DCP, TCD, MTHF, and HEA (mass ratio 18/18/4/60) and 0.65% hexadecimate dissolved in cyclohexane. 48.9 parts of the tungsten chloride solution was continuously dropped into the system over 150 minutes. After that, the reaction was continued for 30 minutes to complete the polymerization to obtain a ring-opening polymerization reaction liquid containing a ring-opening polymer.

After completion of polymerization, the polymerization conversion rate of the monomer measured by gas chromatography was 100% at the end of polymerization.

Hydrogenation The resulting ring-opening polymerization reaction solution was transferred to a pressure-resistant hydrogenation reactor, and a diatomaceous earth-supported nickel catalyst (manufactured by JGC Chemical Co., Ltd. (currently JGC Catalysts and Chemicals Co., Ltd.), product name “T8400RL”, 1.4 parts of nickel loading rate 57%) and 167 parts of cyclohexane were added and reacted at 180° C. and hydrogen pressure of 4.6 MPa for 6 hours to obtain a reaction solution. This reaction solution is filtered under pressure at a pressure of 0.25 MPa (manufactured by IHI Co., Ltd., product name "Funda filter") using Radiolite #500 as a filter bed to remove the hydrogenation catalyst, resulting in a colorless and transparent hydrogenated product. A solution was obtained.

Then, antioxidant per 95 parts of the hydrogenated product: pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by BASF Japan Ltd., product name "Irganox ( (registered trademark) 1010") was added to and dissolved in the hydrogenate solution. Then, it is sequentially filtered through a filter (manufactured by 3M, product name “Zeta Plus Filter 30H”, pore size 0.5 to 1 μm), and further through another metal fiber filter (manufactured by Nichidai Co., Ltd., pore size 0.4 μm). Filtration removed fine solids to give a filtered solution.

Next, this filtered solution was dried using a cylindrical concentration dryer (manufactured by Hitachi, Ltd.) at a temperature of 270°C and a pressure of 1 kPa or less. As a result, the solvent cyclohexane and other volatile components were removed from the filtered solution to obtain a resin solid content. This resin solid content was extruded in a molten state into strands from a die directly connected to the concentration dryer. The extruded resin solid content was cooled and then cut to obtain pellets of the hydrogenated ring-opening polymer (pellets containing the cycloolefin resin a1).

The weight average molecular weight (Mw) of cycloolefin resin a1 was 70,000 when measured in terms of polystyrene by gel permeation chromatography (GPC).

(Production of cycloolefin resin a2)
In the production of cycloolefin resin a1, DCP, TCD in the addition of 7 parts (1% by mass relative to the total amount of monomers (monomers) used for polymerization) and 693 parts of DCP, TCD, MTHF, and a mixture of HEA , MTHF, and HEA in the same manner, except that the mass ratio was changed to 10/20/10/60, to obtain pellets of the hydrogenated ring-opening polymer (pellets containing cycloolefin resin a2). .

The weight average molecular weight (Mw) of the cycloolefin resin a2 was 90,000 when measured in terms of polystyrene by gel permeation chromatography (GPC).

(Production of cycloolefin resin a3)
In the production of cycloolefin resin a1, DCP, TCD in the addition of 7 parts (1% by mass relative to the total amount of monomers (monomers) used for polymerization) and 693 parts of DCP, TCD, MTHF, and a mixture of HEA , MTHF, and HEA in the same manner, except that the mass ratio was changed to 25/25/10/40, to obtain pellets of the hydrogenated ring-opening polymer (pellets containing cycloolefin resin a3). .

The weight average molecular weight (Mw) of cycloolefin resin a3 was 60,000 when measured in terms of polystyrene by gel permeation chromatography (GPC).

(Production of cycloolefin resin a4)
A copolymerization reaction between ethylene and bicyclo[2.2.1]hept-2-ene (common name: norbornene) was carried out as follows.

After circulating nitrogen as an inert gas in a 500 ml glass reaction vessel equipped with a stirrer at a flow rate of 50 Nl/hr for 30 minutes, 200 ml of toluene and 15 g of norbornene were added, and then a decane solution of triisobutylaluminum ( concentration of 1.000 mM/ml) was added. Then, the solvent temperature was adjusted to 40° C. while stirring the polymerization solvent at a rotation speed of 1200 rpm. After the solvent temperature reached 40° C., in addition to nitrogen, ethylene was passed through the reactor at a feed rate of 25 Nl/hr, and after 10 minutes, a toluene solution of triphenylcarbenium (tetrakispentafluorophenyl)borate was added. (concentration 0.005 mM/ml) was added to the reaction vessel, followed by previously prepared (η ⁵ -C ₅ Me ₄ SiMe ₃ )Sc(CH ₂ C ₆ H) from the dropping funnel on top of the reaction vessel. 7 ml of a toluene solution of ₄ NMe ₂ -o) ₂ (concentration 0.005 mM/ml) was added to the glass reaction vessel to initiate polymerization. Here, Me indicates a methyl group, and η5 indicates that the haptic number is ^five .

After 15 minutes had passed, 5 ml of methanol was added to terminate the polymerization to obtain a polymerization solution containing a copolymer of ethylene and norbornene. After that, the polymerization solution was transferred to a separately prepared 1-liter beaker, 5 ml of concentrated hydrochloric acid and a stirrer were added, and the mixture was brought into contact with the mixture for 2 hours under strong stirring for demineralization. The deashed polymerization solution was added to a beaker containing acetone about three times the volume of the polymerization solution with stirring to precipitate a copolymer, and the precipitated copolymer was separated from the filtrate by filtration. The resulting solvent-containing polymer was dried under reduced pressure at 130° C. for 12 hours to obtain an ethylene-norbornene copolymer (a copolymer of ethylene and norbornene) (cycloolefin resin a4). The mass ratio of ethylene and norbornene in the obtained ethylene-norbornene copolymer was 46/54.

After that, the obtained cycloolefin resin a4 was pelletized to obtain pellets containing the cycloolefin resin a4.

The weight average molecular weight (Mw) of cycloolefin resin a4 was 50,000 when measured in terms of polystyrene by gel permeation chromatography (GPC).

(Production of pellets containing cycloolefin resin a5)
A copolymer obtained by copolymerizing a compound C1 represented by the following chemical formula (C1) and HEA at a ratio of 80/20 (mass ratio) was prepared as a cycloolefin resin a5.

After that, the obtained cycloolefin resin a5 was pelletized to obtain pellets containing the cycloolefin resin a5.

The weight average molecular weight (Mw) of the cycloolefin resin a5 was 50,000 when measured in terms of polystyrene by gel permeation chromatography (GPC).

(Synthesis of polyether urethane acrylate U1)
A flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube was charged with polyether polyol (Sannics (registered trademark) diol PP-2000, number average molecular weight 2,000, Sanyo Chemical Industries, Ltd.) as the (ua1) component. Co., Ltd.) 400 parts by mass were charged. Next, while blowing nitrogen gas, the inside of the system is heated to 60° C. and dissolved uniformly, then 54 parts by mass of tolylene diisocyanate is added as the component (ua2), the temperature is further raised to 100° C., and the temperature is maintained for 6 hours. did. Then, after the temperature was lowered to 90° C. and the blowing of nitrogen gas was stopped, 10 parts by mass of 2-hydroxyethyl acrylate as the (ua3) component and 0.5 parts by mass of hydroquinone monomethyl ether as a polymerization inhibitor were added, and the temperature was maintained for 7 hours. . After confirming by IR measurement that the isocyanate group disappeared in the reaction solution, the reaction was terminated to obtain polyether urethane acrylate (U1) having a number average molecular weight of 11,000.

(Preparation of particle dispersion liquid 1)
10 parts by mass of silica particles (Nippon Aerosil Co., Ltd. R972V, average secondary particle diameter 200 nm) and 90 parts by mass of ethanol were stirred and mixed for 30 minutes with a dissolver, and then dispersed using a high-pressure disperser Manton Gaulin. to prepare a dispersion. 65 parts by mass of dichloromethane was added to the resulting dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes for dilution. The resulting solution was filtered through a polypropylene wound cartridge filter TCW-PPS-1N manufactured by Advantech Toyo Co., Ltd. to obtain a particle dispersion liquid 1.

(Preparation of particle dispersion liquid 2)
After stirring and mixing 10 parts by mass of silica particles (Nippon Aerosil Co., Ltd. R812, average secondary particle diameter 50 nm) and 90 parts by mass of ethanol with a dissolver for 30 minutes, dispersion is performed using a high-pressure disperser Manton Gaulin. to prepare a dispersion. 65 parts by mass of dichloromethane was added to the resulting dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes for dilution. The resulting solution was filtered through a polypropylene wound cartridge filter TCW-PPS-1N manufactured by Advantech Toyo Co., Ltd. to obtain a particle dispersion liquid 2.

(Preparation of particle dispersion liquid 3)
10 parts by mass of silica particles (Nippon Aerosil Co., Ltd. R972V, average secondary particle diameter 200 nm) and 90 parts by mass of ethanol were stirred and mixed for 30 minutes with a dissolver, and then dispersed using a high-pressure disperser Manton Gaulin. to prepare a dispersion. 65 parts by mass of ethanol was added to the resulting dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes for dilution. The resulting solution was filtered through a polypropylene wound cartridge filter TCW-PPS-1N manufactured by Advantech Toyo Co., Ltd. to obtain a particle dispersion liquid 3.

(Preparation of coating liquid b1 for forming functional layer)
The following components were mixed to prepare functional layer forming coating solution b1 at 60°C:
Polyether urethane acrylate (U1): 50.0 parts by mass Benzyl acrylate (FA-BZA, manufactured by Showa Denko Materials Co., Ltd., refractive index (25 ° C.) 1.5132): 50.0 parts by mass Particle dispersion liquid 1: 86 .0 parts by mass Methyl ethyl ketone (MEK): 3010.0 parts by mass Cyclohexanone: 90.0 parts by mass.

(Preparation of functional layer forming coating liquid b2)
A functional layer-forming coating solution b2 was prepared by mixing the following components:
Aromatic urethane (meth) acrylate (EBECRYL (registered trademark) 220, manufactured by Daicel Ornex Co., Ltd.): 100.0 parts by mass Particle dispersion liquid 1: 86.0 parts by mass Methyl ethyl ketone (MEK): 3010.0 parts by mass Cyclohexanone: 90.0 parts by mass.

(Preparation of functional layer forming coating liquid b3)
A functional layer-forming coating solution b3 was prepared by mixing the following components:
Benzyl acrylate (FA-BZA, manufactured by Showa Denko Materials Co., Ltd., refractive index (25 ° C.) 1.5132): 100.0 parts by mass Particle dispersion liquid 1: 86.0 parts by mass Methyl ethyl ketone (MEK): 3010.0 parts by mass Part Cyclohexanone: 90.0 parts by mass.

(Preparation of functional layer forming coating liquid b4)
A functional layer-forming coating liquid b4 was prepared by mixing the following components:
Polyether urethane acrylate (U1): 50.0 parts by mass Benzyl acrylate (FA-BZA, manufactured by Showa Denko Materials Co., Ltd., refractive index (25 ° C.) 1.5132): 50.0 parts by mass Particle dispersion liquid 2: 86 .0 parts by mass Methyl ethyl ketone (MEK): 3010.0 parts by mass Cyclohexanone: 90.0 parts by mass.

(Preparation of functional layer forming coating liquid b5)
A functional layer-forming coating liquid b5 was prepared by mixing the following components:
Polyether urethane acrylate (U1): 50.0 parts by mass Polymethyl methacrylate (PMMA) (manufactured by Kaneka Corporation, Mw 150,000, refractive index (25 ° C.) 1.49): 50.0 parts by mass Particle dispersion liquid 1 : 86.0 parts by mass Methyl ethyl ketone (MEK): 3010.0 parts by mass Cyclohexanone: 90.0 parts by mass.

(Preparation of functional layer forming coating liquid b6)
A functional layer-forming coating liquid b6 was prepared by mixing the following components:
Water-based urethane resin (polyurethane water dispersion) (Superflex (registered trademark) 210, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., solid content 35%): 228.6 parts by mass Epoxy compound (Denacol (registered trademark) EX-521, Nagase Chemtex Corporation): 16.0 parts by mass Dihydrazide adipic acid: 4.0 parts by mass Particle dispersion liquid 3: 86.0 parts by mass Ethanol: 3100.0 parts by mass.

(Production of optical film 1 with functional layer)
The pellet containing the cycloolefin resin a1 produced above was dried at 100° C. for 5 hours. Thereafter, the dried pellets were supplied to a single-screw extruder, extruded into a sheet form from a T-die onto a casting drum through a polymer pipe and a polymer filter at a resin temperature of 260°C, and cooled. As a result, a pre-stretched film having a thickness of 80 μm and a width of 675 mm was obtained.

Next, the unstretched film is continuously supplied to a tenter-type transverse stretching machine, and subjected to transverse uniaxial stretching at a stretching temperature of 145° C. and a stretching ratio of 2 times, thereby performing a stretching treatment. The left and right ends in the width direction were cut and removed to produce a cycloolefin resin substrate having a thickness of 60 μm.

Subsequently, using a corona treatment device (manufactured by Kasuga Denki Co., Ltd.), the surface of the cycloolefin resin substrate was subjected to discharge treatment under the conditions of an output of 500 W, an electrode length of 1.35 m, and a transport speed of 5 m/min.

Then, the functional layer forming coating liquid b1 is applied to the discharge-treated surface of the cycloolefin resin base material by a die coating method at a coating speed of 30 m/min and a wet coating amount of 17.5 ml/m ² , and dried. Slow drying was carried out under the condition of a wind (90°C) drying speed of 0.1 g/m ² ·s. After that, under a nitrogen purge, an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm is used to irradiate ultraviolet rays at a dose of 50 mJ / cm ² to cure the coating layer, and the finished film thickness is 1 μm. A layer (cured layer) was formed. Thus, an optical film 1 was produced.

(Production of optical film 2 with functional layer)
An optical film was produced in the same manner as in the production of the above optical film 1, except that the drying conditions after coating of the coating liquid for forming the functional layer were changed to dry rapidly at a drying rate of 3.0 g/m ² ·s. 2 was formed.

(Production of optical film 3 with functional layer)
Optical film 3 was produced in the same manner as in the production of optical film 1 above, except that a film obtained by the following solution casting method was used as the film before stretching.

[Solution casting method]
[Preparation of Dope 1]
A dope 1 having the following composition was prepared. First, methylene chloride and ethanol were added to a pressurized dissolution tank. Next, the pellets of the cycloolefin resin a1 obtained above were charged into a pressurized dissolution tank while being stirred. Then, the mixture was heated to 60° C. and stirred to dissolve the pellets of the cycloolefin resin a1. At this time, the heating temperature was raised from room temperature at a rate of 5° C./min, and after dissolution in 30 minutes, the temperature was lowered at a rate of 3° C./min.

The resulting mixture was filtered using SHP150 manufactured by Roki Techno Co., Ltd. at a filtration flow rate of 300 L/m ² ·h and a filtration pressure of 1.0×10 ⁶ Pa to obtain a dope.

(Composition of Dope 1)
Cycloolefin resin a1: 100 parts by mass Methylene chloride: 235 parts by mass Ethanol: 15 parts by mass.

[Film formation]
Then, using an endless belt casting apparatus, the dope 1 was uniformly cast on a stainless steel belt support at a temperature of 31° C. and a width of 1800 mm. The temperature of the stainless steel belt was controlled at 28°C. The conveying speed of the stainless steel belt was 20 m/min.

The solvent was evaporated on a stainless steel belt support until the amount of residual solvent in the cast film reached 30%. Then, it was peeled off from the stainless steel belt support with a peeling tension of 128 N/m. While the peeled film was transported by a number of rollers, the obtained film-like material was stretched 1.2 times in the width direction under the condition of 150° C. in a tenter. After that, the film was further dried while being transported by rolls, and the ends sandwiched between the tenter clips were slit with a laser cutter and wound up to produce a cycloolefin resin substrate having a thickness of 60 μm.

(Production of optical film 4 with functional layer)
An optical film 4 was formed in the same manner as in the production of the above optical film 1, except that the type of the functional layer forming coating liquid was changed to the functional layer forming coating liquid b2.

(Production of optical film 5 with functional layer)
An optical film 5 was formed in the same manner as in the production of the above optical film 1, except that the type of the functional layer forming coating liquid was changed to the functional layer forming coating liquid b3.

(Production of optical film 6 with functional layer)
An optical film 6 was formed in the same manner as in the production of the above optical film 1, except that the type of the functional layer forming coating liquid was changed to the functional layer forming coating liquid b4.

(Production of optical film 7 with functional layer)
In the production of the optical film 1 described above, the type of pellets used for forming the unstretched film is changed to pellets containing cycloolefin resin a2, and the type of functional layer forming coating liquid is changed to functional layer forming coating liquid b5. An optical film 7 was formed in the same manner except that

(Manufacture of optical film 8)
A cycloolefin resin substrate was produced in the same manner as the optical film 7 described above, and the substrate was used as an optical film 8 .

(Production of optical film 9 with functional layer)
In the production of the above optical film 7, in the formation of the film before stretching, in addition to the pellets containing the cycloolefin resin a2, aluminum oxide nanoparticles (manufactured by EM Japan Co., Ltd., average primary particle size 80 nm) are added to the pellets and An optical film 9 was produced in the same manner, except that the aluminum oxide nanoparticles were supplied to the single-screw extruder in an amount of 0.7% by mass relative to the total mass of the aluminum oxide nanoparticles.

(Production of optical film 10 with functional layer)
Optical film 10 was produced in the same manner as in the production of optical film 7 above, except that the type of pellets used for forming the unstretched film was changed to pellets containing cycloolefin resin a4.

(Manufacture of optical film 11)
A cycloolefin resin substrate was produced in the same manner as in the production of the optical film 1 described above, and the substrate was used as an optical film 11 .

(Manufacture of optical film 12)
Optical film 12 was produced in the same manner as in the production of optical film 11 described above, except that the type of pellets used for forming the unstretched film was changed to pellets containing cycloolefin resin a3.

(Production of optical film 13 with functional layer)
An optical film 13 was produced in the same manner as in the production of the above optical film 1, except that the type of the functional layer forming coating liquid was changed to the functional layer forming coating liquid b6.

(Manufacture of optical film 14)
An optical film 14 was produced in the same manner as in the production of the optical film 11 described above, except that the type of pellets used for forming the unstretched film was changed to pellets containing the cycloolefin resin a5.

In the obtained optical films 1 to 14, the thickness of the cycloolefin resin substrate was 60 μm. In the obtained optical films 1 to 7, 9, 10 and 13, the thickness of the functional layer (cured layer) was 1 μm.

Tables 1 and 2 below show the formulations and manufacturing methods of the optical films obtained above.

<Production of polarizing plate>
[Production of polarizer]
A polyvinyl alcohol film with a thickness of 70 μm was swollen with water at 35°C. The resulting film was immersed in an aqueous solution of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further immersed in an aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water at 45°C. . The obtained film was uniaxially stretched under conditions of a stretching temperature of 55° C. and a stretching ratio of 5 times. This uniaxially stretched film was washed with water and then dried to obtain a polarizer having a thickness of 20 μm.

[Preparation of active energy ray-curable adhesive]
After mixing each of the following components, defoaming was performed to prepare an active energy ray-curable adhesive. The triarylsulfonium hexafluorophosphate was formulated as a 50% propylene carbonate solution, and the solid content of the triarylsulfonium hexafluorophosphate is shown below:
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate: 45 parts by mass Epolead (registered trademark) GT-301 (alicyclic epoxy resin manufactured by Daicel Corporation): 40 parts by mass 1,4-butane Diol diglycidyl ether: 15 parts by mass Triarylsulfonium hexafluorophosphate: 2.3 parts by mass 9,10-dibutoxyanthracene: 0.1 parts by mass 1,4-diethoxynaphthalene: 2.0 parts by mass.

[Manufacture of polarizing plate]
(Manufacture of polarizing plate 1)
The optical film 1 produced above was prepared, and the surface on the functional layer (cured layer) side was subjected to a corona discharge treatment. The conditions for the corona discharge treatment were a corona output intensity of 2.0 kW and a line speed of 18 m/min. Next, the active energy ray-curable adhesive obtained above was applied to the corona discharge-treated surface of the optical film with a bar coater so that the film thickness after curing was about 3 μm. One surface of the polarizer produced above was bonded to the obtained adhesive layer.

On the other hand, as another optical film, a cellulose triacetate film (KC4UA, manufactured by Konica Minolta, Inc., film thickness 40 μm) was prepared, and one surface thereof was subjected to corona treatment in the same manner as described above. Next, the active energy ray-curable adhesive obtained above was applied to the corona discharge-treated surface of KC4UA with a bar coater so that the film thickness after curing was about 3 μm. The other surface of the polarizer with the optical film 1 prepared above was attached to the obtained adhesive layer to obtain a laminate.

Then, from both sides of the laminated laminate, using an ultraviolet irradiation device with a belt conveyor (the lamp uses a D bulb manufactured by Fusion UV Systems Co., Ltd.), ultraviolet light is applied so that the integrated light amount is 750 mJ / cm ² . The polarizing plate 1 was produced by irradiating and curing the adhesive layer.

(Preparation of polarizing plates 2 to 14)
Polarizing plates 2 to 14 were produced in the same manner as in polarizing plate 1 except that optical film 1 was changed to optical films 2 to 14, respectively.

The surfaces of the optical films 2 to 14 to which the corona discharge treatment is applied and the active energy ray-curable adhesive obtained above is applied are those on the functional layer (hardened layer) side of the films having the functional layer (hardened layer). In the case of a film having no functional layer (cured layer), it was taken as either one of the surfaces of the film.

<Manufacture of liquid crystal display device>
(Manufacture of liquid crystal display device 1)
Attached to the observer side (visible side) surface (front) and the light source side surface (back) of the liquid crystal cell of a 40-inch liquid crystal display (BRAVIA (registered trademark) X1) manufactured by Sony Corporation in VA mode. Each polarizing plate was peeled off. Then, the polarizing plate 1 prepared above is attached to the light source side surface (rear surface) and the observer side (viewing side) surface (front surface) of the obtained liquid crystal cell using a transparent acrylic adhesive. , a liquid crystal display device 1 was produced. The polarizing plates were bonded so that the transmission axis of the polarizing plate after bonding coincided with the transmission axis of the originally bonded polarizing plate. The polarizing plates were attached so that the optical film 1 was on the liquid crystal cell side with respect to the polarizer. More specifically, in bonding the polarizing plate to the front surface of the liquid crystal cell, the optical film 1 is on the liquid crystal cell side with respect to the polarizer of the polarizing plate, and the cellulose triacetate film, which is another optical film, is the polarizing plate. , so as to be on the viewing side with respect to the polarizer. In addition, when the polarizing plate is attached to the back surface of the liquid crystal cell, the optical film 1 is on the liquid crystal cell side with respect to the polarizer of the polarizing plate, and the cellulose triacetate film, which is another optical film, is the polarizer of the polarizing plate. It was arranged so as to be on the light source side.

(Manufacture of liquid crystal display devices 2 to 14)
Liquid crystal display devices 2 to 14 were produced in the same manner as the liquid crystal display device 1, except that the polarizing plate 1 was changed to the polarizing plates 2 to 14.

<Evaluation>
[Refractive Index of Optical Film and Polarizer]
Based on JIS K0062-1992, using a multi-wavelength Abbe refractometer (trade name: DR-M2, manufactured by Atago Co., Ltd.), the refractive index at nD:D line (589 nm) at 25 ° C. was obtained above. The refractive indices of the optical films 1 to 14 and the polarizer obtained above were measured. 1-bromonaphthalene was used as an intermediate solution for measurement. Then, for the polarizing plates 1 to 14, the difference in refractive index between the optical films 1 to 14 and the polarizer (refractive index of the optical film−refractive index of the polarizer) was calculated. The results are shown in Table 3 below. In addition, about the optical film with a functional layer, the whole was measured as one film.

In addition, for the optical film with the functional layer, the refractive index of the functional layer alone and the refractive index of the cycloolefin resin substrate alone were measured. For the refractive index of the functional layer alone, a film was formed from the functional layer alone, and the refractive index of the obtained thin film was measured by the method described above. In addition, the refractive index of the cycloolefin resin substrate alone was measured by the method described above for the refractive index of the substrate used in the production of the optical film obtained above. As described above, the refractive index of the functional layer is preferably 0.002 to 0.008 lower than the refractive index of the base layer from the viewpoint of optical scattering.

[Optical Film Haze]
The haze (%) of the optical films 1 to 14 obtained above was measured. Haze was measured according to JIS K 7136:2000 using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.). Here, for optical films having a functional layer (cured layer), values measured from the functional layer side were used. The results are shown in Table 3 below.

[RMS Granularity]
For the liquid crystal display devices 1 to 14 obtained above, the RMS granularity of the display device was calculated as follows. The results are shown in Table 3 below.

(Step 1) Acquisition of image Camera: Sony Corporation (SONY) α7sII,
Lens: Canon EF 70-200mm F2.8L IS II USM,
using ISO 25,600, F 2.8, under a dark room, from a position inclined 10° from the display surface to the viewing side, the display surface of the liquid crystal display device obtained above was photographed when displaying black. .

The display surface was photographed at +45°, +135°, +225 along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate arranged on the viewing side (observer side, front side) of the liquid crystal display device. The measurement was performed from a position tilted 10° from the display surface to the viewing side in each of the directions rotated by 315° (-135°C) and +315° (-45°). At this time, the distance between the position of the display surface of the liquid crystal display device as a reference for photographing and the camera was set at 50 cm.

(Step 2) Analysis of Obtained Images RMS granularity was calculated from captured images according to the following procedure:
1, The obtained photographed image was read as two-dimensional (planar) data using free software (imageJ);
2. A rectangular evaluation area of 2.8 cm x 4 cm was set in the actual captured image;
3. Grayscaling was performed with free software (ImageJ);
4, background correction was performed on the two-dimensional data read in the evaluation area;
5. RMS granularity was calculated from standard deviation σ of gray values (pixel values) in gray scale. This standard deviation σ was taken as the RMS granularity of the displayed image at this measurement angle (angle along the display surface) (RMS granularity at a specific angle);
6, +45°, +135°, +225° (-135°), and +315° (- 45°) In each of the rotated directions, the average value of the RMS granularity (RMS granularity at a specific angle) of the display image photographed from a position tilted 10° from the display surface toward the viewing side is calculated, and the RMS granularity of the display device is calculated. degree.

Here, the free software ImageJ is ImageJ1.32S created by WayneRasband.

Background correction is, for example, outputting different brightness even though the right and left half areas of the image have the same brightness, or Therefore, this correction is performed when an image is output as a result of gradual brightness, and the density gradient is mathematically canceled by approximating the density gradient with a polynomial.

The standard deviation σ of gray values in gray scale was calculated by the following method:
_N pieces of gray value data x ₁ , x ₂ , .

Next, using the population mean m obtained above, variance σ ² was obtained by the following formula (II).

The positive ^square root of this variance σ2 was taken as the standard deviation σ.

(Uneven display)
Camera: Sony Corporation (SONY) α7sII,
Lens: Canon EF 70-200mm F2.8L IS II USM,
was used to observe and photograph the display surface when the display device displayed black in a dark room at ISO 25,600 and F 2.8. The display surface was photographed in a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate arranged on the viewing side (observer side, front side) of the liquid crystal display device. The measurement was performed from a position inclined by 10° from the display surface to the viewing side. At this time, the distance between the position of the display surface of the liquid crystal display device as a reference for photographing and the camera was set at 50 cm. Then, according to the following criteria, the presence or absence of unevenness (roughness) on the displayed image and its degree were confirmed by visual observation or on the displayed image. When the following evaluation results were A to C, it was determined that the display unevenness was at a practically acceptable level. The results are shown in Table 3 below. Note that the high-sensitivity camera is the above-mentioned camera and lens:
≪Evaluation Criteria≫
A: The image shot by the camera is further subjected to gradation processing, and the image is visually confirmed, and display unevenness cannot be confirmed;
B: Slight display unevenness can be confirmed by visually confirming an image that has undergone further gradation processing with respect to the image taken by the camera;
C: Slight display unevenness can be visually confirmed;
D: Display unevenness can be clearly confirmed visually.

It should be noted that, with respect to the absorption axis direction of the polarizer of the polarizing plate arranged on the viewing side, which was photographed during this measurement, it was tilted 10° from the display surface to the viewing side in the direction rotated +45° along the display surface. Some of the images taken from the position are shown in FIGS. 5 and 6. FIG. Specifically, a photographed image of the liquid crystal display device 7 is shown in FIG. 5, and a photographed image of the liquid crystal display device 13 is shown in FIG.

(Production stability)
A plurality of liquid crystal display devices obtained above were manufactured, and the production stability was evaluated by evaluating the luminance unevenness. Specifically, it was observed in a dark room with black display. From the display surface to the viewing side in a direction rotated +45° along the display surface with respect to the absorption axis direction of the polarizer of the polarizing plate arranged on the viewing side (observer side, front side) of the liquid crystal display device Observation was performed visually from a position inclined at 45° to confirm the presence or absence of luminance unevenness. The evaluation is performed on the number of 2,000 units for which observed unevenness is confirmed, and the evaluation criteria are shown below. When the following evaluation result was A or B, it was determined that the production stability was at a practically acceptable level. The results are shown in Table 3 below:
≪Evaluation Criteria≫
A: The number of liquid crystal display devices visually confirmed to have uneven brightness is less than 10/2000 B: The number of liquid crystal display devices visually confirmed to have uneven brightness is 10 or more to less than 19/2000 C: 20 or more/2000 liquid crystal display devices in which luminance unevenness was visually confirmed.

Further, from the results of FIGS. 5 and 6, in the liquid crystal display device 7 having the polarizing plate 7 according to the present invention, the display unevenness is significantly reduced compared to the liquid crystal display device 13 having the polarizing plate 13 according to the comparative example. It was confirmed that Similarly, for liquid crystal display devices having other polarizing plates, in the liquid crystal display device having the polarizing plate according to the present invention, the reduction is significantly reduced compared to the liquid crystal display device having the polarizing plate according to the comparative example. It was confirmed that

From the results in Table 3 above, in the liquid crystal display devices 1 to 10 having the polarizing plates 1 to 10 according to the present invention, the optical film containing the cycloolefin resin base material and the polarizer have a refractive index difference of 0 or more. .02 and the RMS granularity is in the range of 0.30 to 1.34, preferably in the range of 0.30 to 1.30. confirmed. It was also confirmed that these liquid crystal display devices having these polarizing plates have small variations in luminance unevenness between display devices and are excellent in production stability. On the other hand, in the liquid crystal display devices 11 to 14 according to the polarizing plates 11 to 14 according to the comparative examples, the refractive index difference and the RMS granularity between the optical film containing the cycloolefin resin base material and the polarizer were outside the above ranges. At this time, it was confirmed that the occurrence of display unevenness became remarkable.

This application is based on Japanese Patent Application No. 2021-011903 filed on January 28, 2021, the disclosure of which is incorporated by reference in its entirety.

1 Display surface O Reference position (position used as a reference for shooting)
X X direction (direction perpendicular to the absorption axis of the polarizer of the viewing side polarizing plate)
Y Y direction (absorption axis direction of the polarizer of the viewing side polarizing plate)
ZZ direction (normal direction of display surface)
a Direction of the absorption axis of the polarizer of the viewing-side polarizing plate L Straight line in the direction indicating “the position inclined by 10° from the display surface toward the viewing side” L (45) “With respect to the absorption axis direction of the polarizer of the viewing-side polarizing plate , in a direction rotated +45° along the display surface, a straight line in a direction indicating a position inclined by 10° from the display surface to the viewing side 10 liquid crystal display device 30 liquid crystal cell 50 first polarizing plate 51 first polarizer 53 optical film (F1)
55 optical film (F2)
551 cycloolefin resin substrate 552 functional layer 70 second polarizing plate 71 second polarizer 73 optical film (F3)
731 cycloolefin resin substrate 732 functional layer 75 optical film (F4)
90 Light source (backlight).

Claims

In a display device having a polarizing plate and a display device unit,
The polarizing plate has a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
A display device, wherein the RMS granularity of a display image photographed from a position inclined by 10° from the display surface toward the viewing side when the display device displays black is 0.30 to 1.34.
The display device according to claim 1, wherein the RMS granularity is 0.30 to 1.30.
The display device according to claim 1 or 2, wherein the optical film further has a functional layer.
a refractive index difference between the optical film and the polarizer satisfies the following formula (2),
Formula (2) 0.001≦(refractive index of the optical film−refractive index of the polarizer)≦0.015
4. The display device according to claim 3, wherein the functional layer contains acrylic resin or urethane resin, and particles.
The display device according to claim 3 or 4, wherein the functional layer contains an acrylic resin, and the acrylic resin contains a urethane acrylate resin.
The display device according to any one of claims 1 to 5, wherein the display device unit is a vertical alignment (VA) liquid crystal display device unit.
The display device according to any one of claims 1 to 6, wherein at least one of the polarizing plates is arranged on the viewing side of the display cell of the display device unit.
A polarizing plate having a polarizer and an optical film,
The optical film has at least a substrate,
the substrate contains at least a cycloolefin resin, and the refractive index difference between the optical film and the polarizer satisfies the following formula (1);
Formula (1) 0≦(refractive index of the optical film−refractive index of the polarizer)<0.02
In a state in which the polarizing plate is incorporated in the display device, the RMS granularity of the displayed image taken from a position inclined by 10° from the display surface to the viewing side when the display device displays black is 0.30 to 1.34. There is a polarizer.
The polarizing plate according to claim 8, wherein the RMS granularity is 0.30 to 1.30.
The polarizing plate according to claim 8 or 9, wherein the optical film further has a functional layer.
a refractive index difference between the optical film and the polarizer satisfies the following formula (2),
Formula (2) 0.001≦(refractive index of the optical film−refractive index of the polarizer)≦0.015
11. The polarizing plate according to claim 10, wherein the functional layer contains acrylic resin or urethane resin, and particles.
The polarizing plate according to claim 10 or 11, wherein the functional layer contains an acrylic resin, and the acrylic resin contains a urethane acrylate resin.
The polarizer according to any one of claims 8 to 12, wherein the display device has a display device unit, and the display device unit is a vertically aligned (VA) liquid crystal display device unit.
The polarizing plate according to any one of claims 8 to 13, wherein the display device has a display device unit, and the display device unit is incorporated on the viewing side of the display cell.