JP2018087987A - Image display device, production method of image display device and visibility improvement method of image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarization plate composite body excellent in antireflection performance and bright place contrast, which can prevent unevenness of spreading, and excellent in light transmissivity.SOLUTION: A polarization plate composite body is configured so that an optical laminate in which, an optical functional layer is provided on one surface of a light transmissive substrate (1) having birefringence in plane, and which is arranged on a surface of the image display device, and a polarizer in which, from the backlight light source side, at least a light transmissive substrate (2) having birefringence in plane and polarizer (2) are laminated in the order, and which is arranged on the backlight light source side of the image display device, are provided. A slow axis where a refraction index of the light transmissive substrate (1) is large, is arranged in parallel to a vertical direction of a display screen of the image display device, a polarized light enters the light transmissive substrate (2), the light transmissive substrate (2) and the polarizer (2) are laminated so that, an angle formed of a fast axis where the refraction index of the light transmissive substrate (2) is small, and a transmission axis of the polarizer (2) becomes in a range of 0°±30° or 90°±30°.SELECTED DRAWING: None

Description

The present invention relates to a polarizing plate composite, a polarizing plate set, an image display device, a manufacturing method of a polarizing plate composite, a manufacturing method of a polarizing plate set, a manufacturing method of an image display device, and a visibility improving method of the image display device.

Since the liquid crystal display device has features such as power saving, light weight, and thin shape, it is used in various fields in place of the conventional CRT display. In particular, a liquid crystal display device is indispensable for mobile devices such as mobile phones and smartphones that are rapidly spreading in recent years.
In such a liquid crystal display device, a polarizing element is disposed on the image display surface side of the liquid crystal cell, and it is usually required to give hardness so that the polarizing element is not damaged during handling. As a plate protective film, it is a general practice to impart hardness to the image display surface by using a hard coat film in which a hard coat layer is provided on a light transmissive substrate.
Further, in such a liquid crystal display device, for example, a pair of polarizing plates are arranged on the backlight light source on the observer side and the backlight light source side so as to have a crossed Nicols relationship via the liquid crystal cell. The configuration is known.
In the liquid crystal display device having such a configuration, the light emitted from the backlight source passes through the polarizing plate on the backlight source side, the liquid crystal cell, and the polarizing plate on the viewer side, and an image is displayed on the display screen. Is done.

Conventionally, a film made of a cellulose ester typified by triacetyl cellulose has been used as a light-transmitting substrate of a hard coat film. In addition, a polarizing plate of a conventional liquid crystal display device usually has a structure in which a polarizer and a light-transmitting substrate are laminated, and the light-transmitting substrate of the polarizing plate is also represented by triacetyl cellulose. A film made of cellulose ester is used (for example, see Patent Document 1). This is because cellulose ester is excellent in transparency and optical isotropy, and has almost no retardation in the plane (low retardation value). Because it has little influence on the display quality of the device and has a suitable water permeability, moisture remaining in the polarizer when the polarizing plate using the optical laminate is produced can be dried through the optical laminate. It is based on advantages such as being able to.
However, the cellulose ester film is insufficient in moisture resistance and heat resistance, and there is a disadvantage that the polarizing function such as the polarizing function and the hue is lowered when the hard coat film is used as a polarizing plate protective film in a high temperature and high humidity environment. In addition, when used as a light-transmitting substrate for a polarizing plate, the moisture permeability is too high. Therefore, when the moisture resistance test is performed, there is a problem in that the degree of polarization decreases due to discoloration. In addition, cellulose ester is a material that is disadvantageous in terms of cost.

From the problems of such cellulose ester film, it is excellent in transparency, heat resistance and mechanical strength, and is cheaper than cellulose ester film and easily available in the market, or can be produced by a simple method. It is desired to use a versatile film as a light transmissive substrate of an optical laminate or a light transmissive substrate of a polarizing plate. For example, an attempt to use a polyester film such as polyethylene terephthalate as a cellulose ester substitute film (For example, refer to Patent Documents 2 to 5).

However, the polyester film has an aromatic ring with a high polarizability in the molecular chain, so the intrinsic birefringence is extremely large, and the molecular chain is oriented by stretching to give excellent transparency, heat resistance, and mechanical strength. Along with this, birefringence is easily developed. When an optical laminate using a light-transmitting substrate having a birefringence in the surface such as a polyester film is installed on the surface of an image display device, the antireflection performance on the surface of the optical laminate is remarkably high. In some cases, the photopic contrast may be lowered.

Further, in the liquid crystal display device having such a configuration, it is important for improving the luminance of the display screen to efficiently transmit the light emitted from the backlight light source to the display screen. In particular, mobile devices such as smartphones that are rapidly spreading in recent years have a direct effect on the battery duration, and therefore it is required to transmit light from the backlight light source more efficiently to the display screen.

As such a liquid crystal display device, for example, a polarization separation film is provided between a backlight light source and a polarizing plate on the backlight light source side so that polarized light is incident on the polarizing plate on the backlight light source side. A display screen with improved brightness is known. The polarized light separation film is a film having a function of transmitting a specific polarization component and reflecting other polarization components to return to the backlight light source side.
However, when a polarizing plate using a protective film made of a polyester film is used as the polarizing plate on the backlight source side of the liquid crystal display device having such a configuration, the transmittance may be lowered. This is because the polyester film has an aromatic ring with a high polarizability in the molecular chain, so the intrinsic birefringence is extremely large, and the molecular chain is oriented by stretching to give excellent transparency, heat resistance and mechanical strength. This is because it has the property that birefringence easily develops.
For this reason, when a polarizing plate using a light-transmitting substrate having a birefringence index in the plane such as a polyester film is used as a polarizing plate on the backlight side of a liquid crystal display device, Since the polarization state of the specific polarization component that has passed is changed, the transmittance may be reduced.

JP-A-6-51120 JP 2004-205773 A JP 2009-157343 A JP 2010-244059 A WO2011 / 162198

In view of the above situation, the present invention is a polarizing plate composite, a polarizing plate set, an image display device, and a polarizing plate composite that are excellent in antireflection performance and bright place contrast, can also prevent ND, and have excellent light transmittance. The object is to provide a method for producing a body, a method for producing a polarizing plate set, a method for producing an image display device, and a method for improving the visibility of an image display device.
In the present invention, the “visibility improved state” means at least an antireflection performance and a bright place contrast, and further, a state in which ND can be prevented, It is said to have been done.

The present invention relates to an optical laminate having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane and used on the surface of an image display device; From the light source side, at least a light-transmitting substrate (2) having a birefringence in the plane and a polarizer (2) are laminated in this order and arranged on the backlight source side of the image display device. And a slow axis, which is a direction in which the refractive index of the light-transmitting substrate (1) is large, is parallel to the vertical direction of the display screen of the image display device. The polarized light is incident on the light transmissive substrate (2), and the light transmissive substrate (2) and the polarizer (2) are formed of the light transmissive group. The angle formed by the fast axis, which is the direction in which the refractive index of the material (2) is small, and the transmission axis of the polarizer (2) is 0 ° ± It is a polarizing plate composite, which is laminated so as to be 30 ° or 90 ° ± 30 °.

In the polarizing plate composite of the present invention, the light transmissive substrate (1) has a refractive index (nx) in the slow axis direction that is a direction in which the refractive index is large, and a direction orthogonal to the slow axis direction. The difference (nx−ny) from the refractive index (ny) in the fast axis direction is preferably 0.05 or more.
The light transmissive substrate (1) preferably has a retardation of 3000 nm or more.
The polarizing plate composite of the present invention has a primer layer between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive group. When the refractive index (nx) in the slow axis direction of the material (1) and the refractive index (nf) of the optical functional layer are larger (np> nx, nf), or the refractive index (np) of the primer layer When the refractive index (ny) in the fast axis direction of the light transmissive substrate (1) and the refractive index (nf) of the optical functional layer are smaller (np <ny, nf), the thickness of the primer layer is It is preferable that it is 3-30 nm.
The polarizing plate composite of the present invention has a primer layer between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive group. When the refractive index of the material (1) is larger than the refractive index (nx) in the slow axis direction and smaller than the refractive index (nf) of the optical functional layer (nx <np <nf), or the refractive index of the primer layer ( np) is smaller than the refractive index (ny) in the fast axis direction of the light transmissive substrate (1) and larger than the refractive index (nf) of the optical function layer (nf <np <ny), The primer layer preferably has a thickness of 65 to 125 nm.
The polarizing plate composite of the present invention has a primer layer between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive group. It preferably exists between the refractive index (ny) in the fast axis direction of the material (1) and the refractive index (nx) in the slow axis direction of the light-transmitting substrate (ny <np <nx).
Moreover, in the polarizing plate composite of the present invention, the light transmissive substrate (2) and the polarizer (2) have a fast axis which is a direction in which the refractive index of the light transmissive substrate (2) is small. The polarizer (2) is preferably laminated so that the angle formed with the transmission axis of the polarizer (2) is 0 ° ± 15 ° or 90 ° ± 15 °.
The light-transmitting substrate (2) has a refractive index (nx) in the slow axis direction, which is a direction in which the refractive index is large, and a refractive index in the fast axis direction, which is a direction orthogonal to the slow axis direction. The difference (nx−ny) from (ny) is preferably 0.01 or more.
Further, the refractive index (nx) in the slow axis direction, which is the direction in which the refractive index of the light-transmitting substrate (2) is large, and the refractive index in the fast axis direction (in the direction perpendicular to the slow axis direction) ny) and the average refractive index (N) of the light-transmitting substrate (2) have the relationship of the following formula, and the fast axis and the transmission axis of the polarizer (2) form: The angle is preferably 0 ° ± 2 °.
nx>N> ny

In the present invention, an optical laminate having an optical functional layer on one surface of a light-transmitting substrate (1) having an in-plane birefringence index is provided on the polarizer (1) to display an image. The polarizing plate (1) used by being arranged on the surface of the device, and at least the light transmissive substrate (2) and the polarizer (2) having a birefringence in the plane from the backlight light source side in this order. A polarizing plate set having a polarizing plate (2) stacked and used on the backlight source side of the image display device, wherein the optical laminate (1) and the polarizer (1) are The light transmissive substrate (1) is arranged so that the slow axis, which is the direction in which the refractive index is large, and the absorption axis of the polarizer (1) are perpendicular to each other, and the light transmissive substrate (1 ) Is a direction in which the refractive index is large, the slow axis is arranged in parallel with the vertical direction of the display screen of the image display device, Polarized light is incident on the light transmissive substrate (2), and the light transmissive substrate (2) and the polarizer (2) are formed of the light transmissive substrate (2). The angle between the fast axis, which is the direction in which the refractive index is small), and the transmission axis of the polarizer (2) is 0 ° ± 30 ° or 90 ° ± 30 °. It is also a characteristic polarizing plate set.
In the polarizing plate set of the present invention, the light-transmitting substrate (1) has a refractive index (nx) in the slow axis direction, which is a direction in which the refractive index is large, and an advance in a direction perpendicular to the slow axis direction. The difference (nx−ny) from the refractive index (ny) in the phase axis direction is preferably 0.05 or more.
Moreover, the polarizing plate set of this invention WHEREIN: It is preferable that the said transparent base material (1) has a retardation of 3000 nm or more.
In the polarizing plate set of the present invention, a primer layer is provided between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive substrate. When the refractive index (nx) in the slow axis direction of (1) is larger than the refractive index (nf) of the optical functional layer (np> nx, nf), or the refractive index (np) of the primer layer is When the refractive index (ny) in the fast axis direction of the light-transmitting substrate (1) and the refractive index (nf) of the optical functional layer are smaller (np <ny, nf), the thickness of the primer layer is 3 It is preferably ˜30 nm.
In the polarizing plate set of the present invention, a primer layer is provided between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive substrate. When the refractive index is larger than the refractive index (nx) in the slow axis direction of (1) and smaller than the refractive index (nf) of the optical functional layer (nx <np <nf), or the refractive index of the primer layer (np ) Is smaller than the refractive index (ny) in the fast axis direction of the light transmissive substrate (1) and larger than the refractive index (nf) of the optical functional layer (nf <np <ny), the above The primer layer preferably has a thickness of 65 to 125 nm.
In the polarizing plate set of the present invention, a primer layer is provided between the light transmissive substrate (1) and the optical functional layer, and the refractive index (np) of the primer layer is the light transmissive substrate. It exists between the refractive index (ny) in the fast axis direction of (1) and the refractive index (nx) in the slow axis direction of the light-transmitting substrate (1) (ny <np <nx). preferable.

The present invention is also an image display device comprising the polarizing plate composite of the present invention or the polarizing plate set of the present invention.
The image display device of the present invention is preferably a VA mode or IPS mode liquid crystal display device including a white light emitting diode as a backlight light source.
It is preferable to have a polarization separation film between the backlight light source and the light-transmitting substrate (2) having a birefringence in the surface.

The present invention also includes an optical layered body having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane and used on the surface of an image display device; From the backlight light source side, at least a light-transmitting base material (2) having a birefringence in the plane and a polarizer are laminated in this order, and arranged and used on the backlight light source side of the image display device. A polarizing plate composite having a polarizing plate, wherein a slow axis that is a direction in which the refractive index of the light-transmitting substrate (1) is large and a vertical direction of a display screen of the image display device are The step of arranging the optical laminate so as to be parallel, the light transmissive substrate (2), and the polarizer are advanced in a direction in which the refractive index of the light transmissive substrate (2) is small. The angle between the phase axis and the transmission axis of the polarizer is 0 ° ± 30 ° or 90 ° ± 30 °. It is also a method for producing a polarizing plate complex characterized by having a step of laminating the.

According to the present invention, an optical laminated body having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence index in the plane is provided on the polarizer (1), and the image display device The polarizing plate (1) used by being arranged on the surface of the substrate, and at least the light-transmitting substrate (2) and the polarizer (2) having a birefringence in the plane are laminated in this order from the backlight light source side. A polarizing plate set having a polarizing plate (2) disposed on the backlight source side of the image display device, the optical laminate (1) and the polarizer (1) Is arranged such that the slow axis, which is the direction in which the refractive index of the light-transmitting substrate (1) is large, and the absorption axis of the polarizer (1) are perpendicular to each other, and the light-transmitting substrate (1) The slow axis, which is the direction in which the refractive index is large, is arranged in parallel with the vertical direction of the display screen of the image display device. The light-transmitting substrate (2) and the polarizer (2) include a fast axis that is a direction in which the refractive index of the light-transmitting substrate (2) is small, and the polarizer (2 ) Of the polarizing plate set, the step of laminating so that the angle formed with the transmission axis is 0 ° ± 30 ° or 90 ° ± 30 °.

The present invention also includes an optical layered body having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane and used on the surface of an image display device; At least a transparent substrate (2) having a birefringence index in the plane and a polarizer (2) are laminated in this order, and a polarizing plate is provided that is used by being disposed on the backlight source side of the image display device. In the method for manufacturing an image display device, a slow axis that is a direction in which the refractive index of the light transmissive substrate (1) is large and a vertical direction of a display screen of the image display device are parallel to each other. The step of disposing the optical laminate, the light transmissive substrate (2), and the polarizer (2), a fast axis that is a direction in which the refractive index of the light transmissive substrate (2) is small; The step of laminating the polarizer (2) so that the angle formed with the transmission axis is 0 ° ± 30 ° or 90 ° ± 30 °. It is also a method for manufacturing an image display device characterized by having.

The present invention also includes an optical layered body having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane and used on the surface of an image display device; At least a transparent substrate (2) having a birefringence index in the plane and a polarizer (2) are laminated in this order, and a polarizing plate is provided that is used by being disposed on the backlight source side of the image display device. A method for improving the visibility of an image display device, wherein a slow axis, which is a direction in which the refractive index of the light transmissive substrate (1) is large, and a vertical direction of a display screen of the image display device are parallel to each other. In addition, the optical layered body is disposed, and the light-transmitting base material (2) and the polarizer (2) are fastened in a direction in which the refractive index of the light-transmitting base material (2) is small. And the angle between the polarizer and the transmission axis of the polarizer (2) is 0 ° ± 30 ° or 90 ° ± 30 °. It is also a visibility improvement method of the image display apparatus according to claim Rukoto.
The present invention is described in detail below.
In the present invention, unless otherwise specified, curable resin precursors such as monomers, oligomers, and prepolymers are also referred to as “resins”.

As a result of intensive studies, the present inventor has laminated an optical layered body using a light-transmitting substrate having a birefringence in-plane, a light-transmitting substrate and a polarizer, and the backlight of the image display device As a result of intensive studies on a polarizing plate composite having a polarizing plate on which polarized light is incident while being used on the light source side, when installing the optical laminate and the polarizing plate in an image display device, By making the slow axis, which is the direction in which the refractive index of the light-transmitting substrate of the optical laminate is large, be in a specific direction with respect to the display screen of the image display device, antireflection performance and bright place contrast Has been found to be an excellent image display device.
In addition, when a light-transmitting base material having a birefringence in the plane is used for the polarizing plate, the light transmittance of the polarizing plate is a phase advance in the direction in which the refractive index of the light-transmitting base material is small. It has been found that there is an angular dependence between the axis and the transmission axis of the polarizer. That is, the inventors of the present invention have a specific angle range between a fast axis that is a direction in which the refractive index of the light-transmitting substrate having a birefringence in the plane of the polarizing plate is small and a transmission axis of the polarizer. It was found that the light transmittance of the polarizing plate can be improved by laminating so as to be.
And based on such knowledge, the present inventors have conducted further diligent studies. As a result, the optically transmissive substrate and polarization of an optical laminate made of a material such as cellulose ester that has been conventionally used as an optically isotropic material. By using a light-transmitting substrate that has a birefringence, even for the light-transmitting substrate of the plate, the contrast and light transmittance are improved compared to using the optically isotropic material as it is. As a result, the present invention has been completed.
In addition, the film which consists of a cellulose ester represented by the triacetyl cellulose conventionally used for the optical laminated body and the polarizing plate as mentioned above is excellent in optical isotropy, and has almost no phase difference in plane. For this reason, in the case of the optical laminated body or polarizing plate which used the film which consists of this cellulose ester as a light transmissive base material, it was not necessary to consider the installation direction of this light transmissive base material. That is, the above-described problems of antireflection performance, bright place contrast, and light transmittance were caused by using a light transmissive substrate having an in-plane birefringence as the light transmissive substrate of the optical laminate and the polarizing plate. It was caused by.

The polarizing plate composite of the present invention has an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane, and is used by being disposed on the surface of an image display device. The slow axis which has a laminated body and is a direction with a large refractive index of the said transparent base material (1) is arrange | positioned in parallel with the up-down direction of the display screen of the said image display apparatus.
Here, since the image display device is normally installed and used indoors, reflection of light reflected from the wall surface or floor surface on the display screen (the surface of the optical laminate) of the image display device is prevented. By doing so, the antireflection performance can be made excellent.
The present inventors pay attention to the fact that most of the light reflected on the wall surface or floor surface and incident on the display screen of the image display device vibrates in the left-right direction of the display screen. The optical laminate is arranged such that the slow axis, which is the direction in which the refractive index of the light-transmitting substrate (1) is large, is parallel to the vertical direction of the display screen of the image display device. That is, the optical laminate in the polarizing plate composite of the present invention is limited to those used on the surface of an image display device, and the image display in which the polarizing plate composite of the present invention having the optical laminate is installed. In the apparatus, the slow axis, which is the direction in which the refractive index of the light-transmitting substrate (1) is large, is oriented in a direction perpendicular to the vibration direction of the light reflected by the wall surface or floor surface. Yes. Thus, the image display device in which the optical laminate is installed so that the direction of the slow axis, which is the direction in which the refractive index of the light-transmitting substrate (1) is large, becomes a specific direction, has antireflection performance. It is excellent in contrast with light place.
This is because, in the image display device having the configuration in which the polarizing plate composite of the present invention is arranged in the above-described specific state, the light is oscillated in the left-right direction (S-polarized light) that is incident on the display screen. This is because the direction of the fast axis, which is the direction in which the refractive index of the transparent substrate (1) is small, becomes parallel, and external light reflection at the outermost surface can be reduced.
The reason for this is that the reflectance R of the substrate surface having a refractive index of N is:
R = (N−1) ² / (N + 1) ²
In the base material having refractive index anisotropy such as the light-transmitting base material (1) in the optical layered body, the refractive index N is determined by the above configuration in the image display device. This is because the rate at which the refractive index of the fast axis with a small refractive index is applied increases.
For the above reasons, the optical laminate is installed without considering the arrangement direction to the image display device even though it is an optical laminate using the light transmissive substrate (1) having in-plane retardation. And when the optical laminate is installed so that the direction of the slow axis, which is the direction in which the refractive index of the light transmissive substrate (1) is large, becomes a specific direction as in the present invention, the latter The reflectance in this case is lower than the former reflectance. The “state with excellent antireflection performance” in the present invention refers to such a state.
The contrast of the image display device is divided into a dark place contrast and a bright place contrast. The dark place contrast is calculated as (brightness of white display / brightness of black display), and the bright place contrast is {(white display brightness). Luminance + external light reflection) / (black display luminance + external light reflection)}. In any case of contrast, the influence of the denominator becomes larger and the contrast is lowered. That is, if the external light reflection at the outermost surface can be reduced, the bright place contrast is improved as a result.
Note that “the slow axis in which the refractive index of the light-transmitting substrate (1) is large is arranged in parallel with the vertical direction of the display screen of the image display device” means that the slow axis is Means a state in which the optical laminated body is arranged in the image display device in the range of 0 ° ± 40 ° with respect to the vertical direction of the display screen.
In the polarizing plate composite of the present invention, the angle between the slow axis of the light-transmitting substrate (1) and the vertical direction of the display screen is preferably 0 ° ± 30 °, and 0 ° ± 10 ° is more preferable, and 0 ° ± 5 ° is still more preferable. In the polarizing plate composite of the present invention, the angle between the slow axis of the light-transmitting substrate of the optical laminate and the vertical direction of the display screen is 0 ° ± 40 °. The bright place contrast can be improved by the composite.
In the polarizing plate composite of the present invention, the angle between the slow axis of the light-transmitting substrate of the optical laminate and the vertical direction of the display screen is 0 °, which improves the contrast of the light place. It is most preferable when trying. For this reason, the angle between the slow axis of the light transmissive substrate and the vertical direction of the display screen is preferably 0 ° ± 30 °, more preferably 0 °, rather than 0 ° ± 40 °. ° ± 10 °. Furthermore, when the angle between the slow axis of the light-transmitting substrate and the vertical direction of the display screen is 0 ° ± 5 °, the bright contrast can be improved to the same level as when the angle is 0 °. This is more preferable.
In this specification, regarding the angle formed by the two axes, the angle formed clockwise with respect to the reference angle is plus (+) as viewed from the observer side, and is counterclockwise with respect to the reference angle. The angle formed is minus (−). When an angle is indicated without particular notation, it means a case where the angle is clockwise with respect to a reference angle (that is, a case where the angle is positive).

The light-transmitting substrate (1) having a birefringence index in the plane is not particularly limited, and examples thereof include substrates made of polycarbonate, acrylic, polyester, etc. Among them, in terms of cost and mechanical strength. An advantageous polyester substrate is preferred. In the following description, the light-transmitting substrate (1) having a birefringence in the plane will be described as a polyester substrate.
In the present invention, as the light transmissive substrate (1), even if it is a light transmissive substrate made of cellulose ester or the like conventionally used as an optically isotropic material, the birefringence is intentionally set. It can be used by having it.

It is preferable that the polyester base material has a retardation of 3000 nm or more because it can prevent the occurrence of azimuth and the visibility is extremely improved. When it is less than 3000 nm, when the polarizing plate composite of the present invention is used in a liquid crystal display device (LCD), rainbow-colored stripes are visually recognized, and the display quality may deteriorate. On the other hand, the upper limit of the retardation of the polyester base material is not particularly limited, but is preferably about 30,000 nm. If it exceeds 30,000 nm, the film thickness becomes considerably large, which is not preferable.
It is preferable that the retardation of the said polyester base material is 5000-25000 nm from a viewpoint of thin film formation. A more preferable range is 7000 to 20,000 nm, and in this range, the optical laminate is in the image display device, and the slow axis of the polyester base is 0 ° with respect to the vertical direction of the display screen. When arranged in a range of ± 30 ° to 40 °, that is, the slow axis of the polyester base material is arranged with an angle slightly shifted from the completely parallel to the vertical direction of the display screen. Even if it is, it is possible to further improve the anti-Nizidra property. Note that the optical laminate has a retardation of 3000 nm or more even if the slow axis of the polyester base material is ± 30 ° to 40 ° from the complete parallel to the vertical direction of the display screen. For example, it has Nizimura prevention properties, and there is no problem in practical use.

The retardation is the refractive index (nx) in the direction having the highest refractive index (slow axis direction) in the plane of the polyester substrate, and the refraction in the direction orthogonal to the slow axis direction (fast axis direction). It is represented by the following formula by the rate (ny) and the thickness (d) of the polyester base material.
Retardation (Re) = (nx−ny) × d
The retardation can be measured, for example, by KOBRA-WR manufactured by Oji Scientific Instruments (measurement angle 0 °, measurement wavelength 589.3 nm).
Further, using two polarizing plates, the orientation axis direction (principal axis direction) of the polyester substrate is obtained, and the refractive indexes (nx, ny) of two axes orthogonal to the orientation axis direction are Abbe's refractive indices. It calculates | requires by the total (NAGO-4T by Atago Co., Ltd.). Here, an axis showing a larger refractive index is defined as a slow axis. The polyester base material thickness d (nm) is measured using an electric micrometer (manufactured by Anritsu), and the unit is converted to nm. Retardation can also be calculated from the product of the refractive index difference (nx−ny) and the thickness d (nm) of the film.
The refractive index can be measured by using an Abbe refractometer or an ellipsometer, or by using a spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation) of the optical functional layer in the optical laminate. You may measure the average reflectance (R) of wavelength 380-780 nm, and may obtain | require the value of refractive index (n) from the obtained average reflectance (R) using the following formula | equation.
The average reflectance (R) of the optical functional layer is a surface (back surface) on which 50 μm PET without easy adhesion treatment is coated with each raw material composition to form a cured film having a thickness of 1 to 3 μm, and PET is not applied. In order to prevent back surface reflection, the average reflectance of each cured film was measured after applying a black vinyl tape (for example, Yamato vinyl tape No 200-38-21 38 mm width) having a width larger than the measurement spot area. The refractive index of the polyester base material was measured after black vinyl tape was similarly applied to the surface opposite to the measurement surface.
R (%) = (1-n) ² / (1 + n) ²
Further, as a method for measuring the refractive index of the optical functional layer after becoming an optical layered product, a cured film of each layer is scraped off with a cutter or the like to prepare a powder sample, and JIS K7142 (2008) B method (powder) Alternatively, the Becke method according to (for granular transparent materials) can be used. In the Becke method, a Cargill reagent having a known refractive index is used, the powder sample is placed on a glass slide, the reagent is dropped on the sample, and the sample is immersed in the reagent. This is observed by using a microscope, and this is a method in which the refractive index of the sample is the refractive index of the reagent in which the bright line generated in the sample outline due to the difference in refractive index between the sample and the reagent;
In the case of a polyester base material, the refractive index (nx, ny) differs depending on the direction. Therefore, the spectrophotometer (V7100 type, Automatic absolute reflectance measurement unit VAR-7010 (manufactured by JASCO Corporation), polarization measurement: S-polarized light, the slow axis of the light-transmitting substrate is installed in parallel, and the fast axis is installed in parallel In this case, the reflectivity (nx, ny) of the slow axis and the fast axis can be calculated from the above formula.

In the present invention, when the polyester base material is a PET base material made of polyethylene terephthalate (PET) described later, the nx-ny (hereinafter also referred to as Δn) is 0.05 or more. Is preferred. If Δn is less than 0.05, the fast axis refractive index is large, and thus the above-described image display apparatus may not be improved in bright place contrast. Further, the film thickness necessary for obtaining the retardation value described above may be increased. On the other hand, the Δn is preferably 0.25 or less. If it exceeds 0.25, it becomes necessary to stretch the PET base material excessively, so that the PET base material is likely to be torn and torn, and the practicality as an industrial material may be significantly reduced.
From the above viewpoint, the more preferable lower limit of Δn in the case of the PET substrate is 0.07, and the more preferable upper limit is 0.20. In addition, when said (DELTA) n exceeds 0.20, the durability of the PET base material in a heat-and-moisture resistance test may be inferior. Since the durability in the wet heat resistance test is excellent, the more preferable upper limit of Δn in the case of the PET base material is 0.15.
In addition, as (nx) in the case of the said PET base material, it is preferable that it is 1.66-1.78, a more preferable minimum is 1.68, and a more preferable upper limit is 1.73. Moreover, as (ny) in the case of the said PET base material, it is preferable that it is 1.55-1.65, a more preferable minimum is 1.57 and a more preferable upper limit is 1.62.
When nx and ny are in the above-described range and satisfy the above-described relationship of Δn, it is possible to improve suitable antireflection performance and bright place contrast.
Moreover, when the said polyester base material is a PEN base material which uses the polyethylene naphthalate (PEN) mentioned later as a raw material, as for said (DELTA) n, a preferable minimum is 0.05 and a preferable upper limit is 0.30. If Δn is less than 0.05, the film thickness necessary to obtain the retardation value described above is increased, which is not preferable. On the other hand, if the above Δn exceeds 0.30, the PEN substrate tends to be torn and torn, and the practicality as an industrial material may be significantly reduced. The more preferable lower limit of Δn in the case of the PEN substrate is 0.07, and the more preferable upper limit is 0.27. This is because if Δn is smaller than 0.07, it is difficult to obtain the sufficient effect of suppressing the above-mentioned azimuth and color change. In addition, when said (DELTA) n exceeds 0.27, durability of the PEN base material in a heat-and-moisture resistance test may be inferior. Moreover, since the durability in a heat-and-moisture resistance test is excellent, a more preferable upper limit of Δn in the case of the PEN substrate is 0.25.
In addition, as (nx) in the case of the said PEN base material, it is preferable that it is 1.70-1.90, a more preferable minimum is 1.72 and a more preferable upper limit is 1.88. Moreover, as (ny) in the case of the said PEN base material, it is preferable that it is 1.55-1.75, a more preferable minimum is 1.57 and a more preferable upper limit is 1.73.

The material constituting the polyester base material is not particularly limited as long as it satisfies the retardation described above, but is synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Examples include linear saturated polyester. Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene naphthalate (polyethylene-2,6-naphthalate, polyethylene-1,4-naphthalate). , Polyethylene-1,5-naphthalate, polyethylene-2,7-naphthalate, polyethylene-2,3-naphthalate) and the like. The polyester used for the polyester substrate may be a copolymer of these polyesters. The polyester is mainly used (for example, a component of 80 mol% or more), and a small proportion (for example, 20 mol% or less). It may be blended with these types of resins. Polyethylene terephthalate or polyethylene naphthalate is particularly preferable as the polyester because of good balance between mechanical properties and optical properties. In particular, it is preferably made of polyethylene terephthalate (PET). This is because polyethylene terephthalate is highly versatile and easily available. In the present invention, an optical laminate that can produce a liquid crystal display device with high display quality can be obtained even with a highly versatile film such as PET. Furthermore, PET is excellent in transparency, heat or mechanical properties, can control the retardation by stretching, has a large intrinsic birefringence, and can obtain a large retardation relatively easily even when the film thickness is small.

The method for obtaining the polyester base material is not particularly limited as long as the above-described retardation is satisfied. For example, the polyester, such as PET, as a material is melted and extruded into a sheet to form glass. The method of heat-processing after transverse stretching using a tenter etc. at the temperature more than transition temperature is mentioned.
The transverse stretching temperature is preferably 80 to 130 ° C, more preferably 90 to 120 ° C. Further, the transverse draw ratio is preferably 2.5 to 6.0 times, more preferably 3.0 to 5.5 times. When the transverse draw ratio exceeds 6.0 times, the transparency of the resulting polyester base material tends to be lowered, and when the transverse draw ratio is less than 2.5 times, the draw tension becomes small. In some cases, the birefringence of the substrate becomes small, and the retardation cannot be increased to 3000 nm or more.
In the present invention, the unstretched polyester is subjected to transverse stretching under the above conditions using a biaxial stretching test apparatus, and then stretched in the flow direction with respect to the transverse stretching (hereinafter also referred to as longitudinal stretching). Also good. In this case, the longitudinal stretching preferably has a stretching ratio of 2 times or less. When the draw ratio of the above-mentioned longitudinal stretching exceeds twice, the value of Δn may not be within the preferred range described above.
The treatment temperature during the heat treatment is preferably 100 to 250 ° C, more preferably 180 to 245 ° C.

Examples of the method for controlling the retardation of the polyester substrate produced by the above-described method to 3000 nm or more include a method of appropriately setting the draw ratio, the drawing temperature, and the film thickness of the produced polyester substrate. Specifically, for example, the higher the stretching ratio, the lower the stretching temperature, and the thicker the film, the easier it is to obtain high retardation. The lower the stretching ratio, the higher the stretching temperature, and the film thickness. The thinner, the easier it is to obtain low retardation.

The thickness of the polyester substrate is preferably in the range of 5 to 500 μm. If it is less than 5 μm, tearing, tearing and the like are likely to occur, and the utility as an industrial material may be significantly reduced. On the other hand, if it exceeds 500 μm, the polyester base material is very rigid, the flexibility specific to the polymer film is lowered, and the practicality as an industrial material is also lowered, which is not preferable. The minimum with more preferable thickness of the said polyester base material is 10 micrometers, a more preferable upper limit is 300 micrometers, and a still more preferable upper limit is 150 micrometers.

The polyester base material preferably has a transmittance in the visible light region of 80% or more, more preferably 84% or more. In addition, the said transmittance | permeability can be measured by JISK7361-1 (The test method of the total light transmittance of a plastic-transparent material).

In the present invention, the polyester substrate may be subjected to surface treatment such as saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, and flame treatment without departing from the spirit of the present invention. Good.

The optical functional layer is preferably a hard coat layer having a hard coat performance, and the hard coat layer has a hardness in a pencil hardness test (load 4.9 N) according to JIS K5600-5-4 (1999). It is preferably H or more, and more preferably 2H or more.
The hard coat layer is a layer that ensures the hard coat properties of the surface of the optical laminate, for example, for a hard coat layer containing an ionizing radiation curable resin that is a resin curable by ultraviolet rays and a photopolymerization initiator. It is preferably formed using a composition.

In the optical layered body, examples of the ionizing radiation curable resin include compounds having one or more unsaturated bonds such as a compound having an acrylate functional group. Examples of the compound having one unsaturated bond include ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Examples of the compound having two or more unsaturated bonds include polymethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and the like, and ethylene oxide ( A polyfunctional compound modified with EEO), or a reaction product of the polyfunctional compound and (meth) acrylate (for example, poly (meth) acrylate ester of polyhydric alcohol). It is possible. In the present specification, “(meth) acrylate” refers to methacrylate and acrylate.

In addition to the above compounds, polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyds having a relatively low molecular weight (number average molecular weight of 300 to 80,000, preferably 400 to 5000) having an unsaturated double bond. Resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can also be used as the ionizing radiation curable resin. The resin in this case includes all dimers, oligomers, and polymers other than monomers.
Preferred compounds in the present invention include compounds having 3 or more unsaturated bonds. When such a compound is used, the crosslink density of the hard coat layer to be formed can be increased, and the coating hardness can be improved.
Specifically, in the present invention, pentaerythritol triacrylate, pentaerythritol tetraacrylate, polyester polyfunctional acrylate oligomer (3 to 15 functional), urethane polyfunctional acrylate oligomer (3 to 15 functional) and the like are used in appropriate combination. Is preferred.

The ionizing radiation curable resin can be used in combination with a solvent-drying resin. By using the solvent-drying resin in combination, film defects on the coated surface can be effectively prevented. In addition, the said solvent dry type resin means resin which becomes a film only by drying the solvent added in order to adjust solid content at the time of coating, such as a thermoplastic resin.
The solvent-drying resin that can be used in combination with the ionizing radiation curable resin is not particularly limited, and a thermoplastic resin can be generally used.
The thermoplastic resin is not particularly limited. For example, a styrene resin, a (meth) acrylic resin, a vinyl acetate resin, a vinyl ether resin, a halogen-containing resin, an alicyclic olefin resin, a polycarbonate resin, or a polyester resin. Examples thereof include resins, polyamide-based resins, cellulose derivatives, silicone-based resins, rubbers, and elastomers. The thermoplastic resin is preferably amorphous and soluble in an organic solvent (particularly a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoints of film forming properties, transparency, and weather resistance, styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) and the like are preferable.

Moreover, the said composition for hard-coat layers may contain the thermosetting resin.
The thermosetting resin is not particularly limited. For example, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation Examples thereof include resins, silicon resins, polysiloxane resins, and the like.

The photopolymerization initiator is not particularly limited, and known ones can be used. For example, specific examples of the photopolymerization initiator include acetophenones, benzophenones, Michler benzoylbenzoate, α-amylo. Examples include oxime esters, thioxanthones, propiophenones, benzyls, benzoins, and acylphosphine oxides. In addition, it is preferable to use a mixture of photosensitizers, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

As the photopolymerization initiator, when the ionizing radiation curable resin is a resin system having a radical polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc. may be used alone or in combination. It is preferable to use it. When the ionizing radiation curable resin is a resin system having a cationic polymerizable functional group, the photopolymerization initiator may be an aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt, metallocene compound, benzoin sulfone. It is preferable to use acid esters alone or as a mixture.
As the initiator used in the present invention, in the case of an ionizing radiation curable resin having a radically polymerizable unsaturated group, 1-hydroxy-cyclohexyl-phenyl-ketone is compatible with the ionizing radiation curable resin, and yellow This is preferable because of little change.

The content of the photopolymerization initiator in the hard coat layer composition is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin. When the amount is less than 1 part by mass, the hardness of the hard coat layer in the optical laminate may not be within the above-described range. When the amount exceeds 10 parts by mass, the ionizing radiation does not reach the deep part of the coated film. This is because the internal curing is not promoted, and there is a possibility that a pencil hardness of 3H or higher on the surface of the target hard coat layer may not be obtained.
The minimum with more preferable content of the said photoinitiator is 2 mass parts, and a more preferable upper limit is 8 mass parts. When the content of the photopolymerization initiator is in this range, a hardness distribution does not occur in the film thickness direction, and uniform hardness is likely to occur.

The hard coat layer composition may contain a solvent.
As said solvent, it can select and use according to the kind and solubility of the resin component to be used, for example, ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol etc.), ethers ( Dioxane, tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), Halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cello) Lube, ethyl cellosolve), cellosolve acetates, sulfoxides (dimethyl sulfoxide), amides (dimethylformamide, dimethylacetamide, etc.) and the like can be exemplified, it may be a mixed solvent thereof.
In particular, in the present invention, it is preferable that at least one of methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or a mixture thereof is included in the ketone solvent because of excellent compatibility with the resin and coating properties.

Although it does not specifically limit as a content rate (solid content) of the raw material in the said composition for hard-coat layers, Usually, it is preferable to set it as 5-70 mass%, especially 25-60 mass%.

The hard coat layer composition increases the hardness of the hard coat layer, suppresses curing shrinkage, prevents blocking, controls the refractive index, imparts antiglare properties, and properties of particles and the surface of the hard coat layer Depending on the purpose such as changing the color, conventionally known organic, inorganic fine particles, dispersants, surfactants, antistatic agents, silane coupling agents, thickeners, anti-coloring agents, coloring agents (pigments, dyes), A foaming agent, a leveling agent, a flame retardant, an ultraviolet absorber, an adhesion-imparting agent, a polymerization inhibitor, an antioxidant, a surface modifier, and the like may be added.

Moreover, the said composition for hard-coat layers may mix and use a photosensitizer, As a specific example, n-butylamine, a triethylamine, poly-n-butylphosphine etc. are mentioned, for example.

The method for preparing the hard coat layer composition is not particularly limited as long as each component can be uniformly mixed. For example, the composition can be performed using a known apparatus such as a paint shaker, a bead mill, a kneader, or a mixer.

Moreover, it does not specifically limit as a method of apply | coating the said composition for hard-coat layers on the said light-transmissive base material (1), For example, a gravure coat method, a spin coat method, a dip method, a spray method, a die coat method, Well-known methods such as a bar coat method, a roll coater method, a meniscus coater method, a flexographic printing method, a screen printing method, and a pea coater method can be exemplified.

The coating film formed by applying the hard coat layer composition on the light transmissive substrate (1) is preferably heated and / or dried as necessary and cured by irradiation with active energy rays or the like. .

Examples of the active energy ray irradiation include irradiation with ultraviolet rays or electron beams. Specific examples of the ultraviolet light source include light sources such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, and a metal halide lamp. Moreover, as a wavelength of an ultraviolet-ray, the wavelength range of 190-380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as a cockcroft-wald type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type.

In addition, since the preferable film thickness (at the time of hardening) of the said hard-coat layer is 0.5-100 micrometers, More preferably, it is 0.8-20 micrometers, Since curl prevention property and crack prevention property are especially excellent, Most preferably, it is the range of 2-10 micrometers. It is. The film thickness of the hard coat layer is an average value (μm) obtained by observing a cross section with an electron microscope (SEM, TEM, STEM) and measuring any 10 points. As for the film thickness of the hard coat layer, as an alternative method, any 10 points may be measured using a Digimatic Indicator IDF-130 manufactured by Mitutoyo Corporation to obtain an average value.

By containing an antistatic agent in the hard coat layer composition, antistatic performance can be imparted to the hard coat layer.
As the antistatic agent, conventionally known ones can be used. For example, a cationic antistatic agent such as a quaternary ammonium salt, fine particles such as tin-doped indium oxide (ITO), a conductive polymer, or the like can be used. Can do.
When using the said antistatic agent, it is preferable that the content is 1-30 mass% with respect to the total mass of all the solid content.

Moreover, it is preferable that the said optical laminated body has a low-refractive-index layer further on the said hard-coat layer.
The low refractive index layer is preferably 1) a resin containing inorganic fine particles of low refractive index such as silica or magnesium fluoride, 2) a fluorine-based resin which is a low refractive index resin, 3) silica or magnesium fluoride, etc. Fluorine resin containing low-refractive-index inorganic fine particles, 4) Any of low-refractive-index inorganic thin films such as silica or magnesium fluoride. For resins other than fluorine-based resins, the same resins as the binder resins described above can be used.
Moreover, it is preferable that the silica mentioned above is a hollow silica fine particle, and such a hollow silica fine particle can be produced by, for example, a production method described in Examples of JP-A-2005-099778.
These low refractive index layers preferably have a refractive index of 1.47 or less, particularly 1.42 or less.
In addition, the thickness of the low refractive index layer is not limited, but it may be set appropriately from the range of about 10 nm to 1 μm.

As the fluororesin, a polymerizable compound containing a fluorine atom in at least a molecule or a polymer thereof can be used. Although it does not specifically limit as a polymeric compound, For example, what has hardening reactive groups, such as a functional group hardened | cured by ionizing radiation, and a polar group thermally cured, is preferable. Moreover, the compound which has these reactive groups simultaneously may be sufficient. In contrast to this polymerizable compound, a polymer has no reactive groups as described above.

As the polymerizable compound having a functional group that is cured by ionizing radiation, fluorine-containing monomers having an ethylenically unsaturated bond can be widely used. More specifically, to illustrate fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) Can do. As those having a (meth) acryloyloxy group, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 2- (perfluorobutyl) ) Ethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2- (perfluorooctyl) ethyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, α-trifluoro (Meth) acrylate compounds having a fluorine atom in the molecule, such as methyl methacrylate and α-trifluoroethyl methacrylate; a C 1-14 fluoroalkyl group having at least 3 fluorine atoms in the molecule, fluoro A cycloalkyl group or a fluoroalkylene group and at least two (medium There are also fluorine-containing polyfunctional (meth) acrylic acid ester compounds having an acryloyloxy group.

Preferable examples of the thermosetting polar group include hydrogen bond forming groups such as a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. These are excellent not only in adhesion to the coating film but also in affinity with inorganic ultrafine particles such as silica. Examples of the polymerizable compound having a thermosetting polar group include 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer; fluoroethylene-hydrocarbon vinyl ether copolymer; epoxy, polyurethane, cellulose, phenol, polyimide, and the like. Examples include fluorine-modified products of each resin.
Examples of the polymerizable compound having both a functional group curable by ionizing radiation and a polar group curable by heat include acrylic or methacrylic acid moieties and fully fluorinated alkyl, alkenyl, aryl esters, fully or partially fluorinated vinyl ethers, fully Alternatively, partially fluorinated vinyl esters, fully or partially fluorinated vinyl ketones and the like can be exemplified.

Moreover, as a fluorine resin, the following can be mentioned, for example.
Polymer of monomer or monomer mixture containing at least one fluorine-containing (meth) acrylate compound of a polymerizable compound having an ionizing radiation curable group; at least one fluorine-containing (meth) acrylate compound; and methyl (meth) Copolymers with (meth) acrylate compounds that do not contain fluorine atoms in the molecule such as acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; fluoroethylene , Fluorine-containing compounds such as vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoropropylene, 1,1,2-trichloro-3,3,3-trifluoropropylene, hexafluoropropylene Monomer homopolymer or Copolymer such as. Silicone-containing vinylidene fluoride copolymers obtained by adding a silicone component to these copolymers can also be used. The silicone components in this case include (poly) dimethylsiloxane, (poly) diethylsiloxane, (poly) diphenylsiloxane, (poly) methylphenylsiloxane, alkyl-modified (poly) dimethylsiloxane, azo group-containing (poly) dimethylsiloxane, Dimethyl silicone, phenylmethyl silicone, alkyl / aralkyl modified silicone, fluorosilicone, polyether modified silicone, fatty acid ester modified silicone, methyl hydrogen silicone, silanol group containing silicone, alkoxy group containing silicone, phenol group containing silicone, methacryl modified silicone, acrylic Modified silicone, amino modified silicone, carboxylic acid modified silicone, carbinol modified silicone, epoxy modified silicone, mercapto modified silicone Over emissions, fluorine-modified silicones, polyether-modified silicone and the like. Of these, those having a dimethylsiloxane structure are preferred.

Furthermore, non-polymers or polymers composed of the following compounds can also be used as the fluororesin. That is, a fluorine-containing compound having at least one isocyanato group in the molecule is reacted with a compound having at least one functional group in the molecule that reacts with an isocyanato group such as an amino group, a hydroxyl group, or a carboxyl group. Compound obtained: a compound obtained by reacting a fluorine-containing polyol such as fluorine-containing polyether polyol, fluorine-containing alkyl polyol, fluorine-containing polyester polyol, fluorine-containing ε-caprolactone modified polyol with a compound having an isocyanato group Can be used.

Moreover, each binder resin as described above can be mixed and used together with the above-described polymerizable compound or polymer having a fluorine atom. Furthermore, various additives and solvents can be used as appropriate in order to improve the curing agent for curing reactive groups and the like, to improve the coating property, and to impart antifouling properties.

In the formation of the low refractive index layer, 0.5 to 5 mPa · s (25 ° C.) at which a preferable coating property is obtained for the viscosity of the composition for a low refractive index layer obtained by adding a low refractive index agent and a resin, It is preferable to set it as the range of 0.7-3 mPa * s (25 degreeC) preferably. An antireflection layer excellent in visible light can be realized, a uniform thin film with no coating unevenness can be formed, and a low refractive index layer particularly excellent in adhesion can be formed.

The resin curing means may be the same as the curing means in the hard coat layer described later. When a heating means is used for the curing treatment, it is preferable to add a thermal polymerization initiator that generates, for example, a radical by heating to start polymerization of the polymerizable compound, to the fluororesin composition.

As a method for producing the optical layered body, for example, a hard coat layer coating film is formed on the polyester substrate prepared by the above-described method, and after drying as necessary, the hard coat layer coating film is formed. Curing to form a hard coat layer. And the said optical laminated body can be manufactured by forming the said low-refractive-index layer on the said hard-coat layer by a well-known method as needed.
Moreover, it is although it does not specifically limit as a drying method of the said coating film for hard-coat layers, Generally, it is good to dry for 3 to 120 second at 30-120 degreeC.

What is necessary is just to select a well-known method suitably as a method of hardening the said coating film for hard-coat layers according to a structural component. For example, if the binder resin component to be contained is of an ultraviolet curable type, the coating film may be cured by irradiating with ultraviolet rays.
When irradiating the ultraviolet light is preferably ultraviolet irradiation amount is 80 mJ / cm ² or more, more preferably 100 mJ / cm ² or more, more preferably 130 mJ / cm ² or more.

The optical laminate preferably has a primer layer between the light transmissive substrate and the optical functional layer.
The primer layer is a layer provided for the first purpose to improve the adhesion between the polyester base material and the hard coat layer described above. The preferred thickness of the primer layer is an interference fringe resulting from the provision of the primer layer. From the viewpoint of preventing the occurrence of the above, in relation to the refractive index (nx, ny) of the light transmissive substrate (1), the refractive index (nh) of the optical functional layer, and the refractive index (np) of the primer layer, As appropriate.
(1) When the refractive index (np) of the primer layer is larger than the refractive index (nx) in the slow axis direction of the light-transmitting substrate (1) and the refractive index (nf) of the optical functional layer (np > Nx, nf), or the refractive index (np) of the primer layer is the refractive index (ny) in the fast axis direction of the light-transmitting substrate (1) and the refractive index (nf) of the optical functional layer. Is smaller (np <ny, nf), the primer layer preferably has a thickness of 3 to 30 nm.
(2) The refractive index (np) of the primer layer is larger than the refractive index (nx) in the slow axis direction of the light transmissive substrate (1), and is higher than the refractive index (nf) of the optical functional layer. When it is small (nx <np <nf), or the refractive index (np) of the primer layer is smaller than the refractive index (ny) in the fast axis direction of the light-transmitting substrate (1), the optical function When the refractive index (nf) of the layer is larger (nf <np <ny), the primer layer preferably has a thickness of 65 to 125 nm.
(3) The refractive index (np) of the primer layer is such that the refractive index (ny) in the fast axis direction of the light transmissive substrate (1) and the refractive index in the slow axis direction of the light transmissive substrate ( nx) (ny <np <nx), the thickness of the primer layer is not particularly limited from the viewpoint of preventing interference fringes. From the viewpoint of reducing the amount of reflection at the interface between the primer layer and the light-transmitting substrate (1) and weakening the interference fringes, the refractive index (np) of the primer layer is (nx + ny) / 2. The closer it is to the better.

The reason why the thickness of the primer layer is preferable in the above (1) and (2) is that in (1), the interface between the primer layer and the optical functional layer (interface A), the light-transmitting substrate (1), When comparing the interface with the primer layer (interface B), the magnitude relationship of the change in the refractive index with respect to the incident external light is opposite between the interface A and the interface B. Therefore, when external light is reflected at the interface, if one of the interfaces A and B is free-end reflection, the other is fixed-end reflection, and the phase is reversed. This is because the light interferes and the intensity decreases.
On the other hand, in (2), since the change in refractive index is the same between the interface A and the interface B, the phase of the reflected light at the interface A and the interface B is the same. This is because when the wavelength is 1/4 of the light wavelength, the reflected light at both interfaces interferes and the intensity decreases. Here, the range of the thickness of the primer layer in (2) is that the refractive index of the primer layer is usually about 1.47 to 1.63 as will be described later. Is a value calculated with a light wavelength of 380 to 780 nm.
In addition, when the difference in refractive index between the primer layer, the light-transmitting substrate and the optical functional layer is equal, the reflectance at both interfaces is also equal, and the effect of interference in the above (1) and (2) is most exhibited. Is done.

In the case of the above (1), the primer layer preferably has a thickness of 3 to 30 nm. If it is less than 3 nm, the adhesion between the polyester substrate and the hard coat layer may be insufficient, and if it exceeds 30 nm, the interference fringe preventing property of the optical laminate may be insufficient. The more preferable lower limit of the thickness of the primer layer in the case of (1) is 10 nm, and the more preferable upper limit is 20 nm.
In the case of (2), the primer layer preferably has a thickness of 65 to 125 nm. Outside this range, the interference fringe preventing property of the optical layered body of the present invention may be insufficient. The more preferable lower limit of the thickness of the primer layer in the case of (2) is 70 nm, and the more preferable upper limit is 110 nm.
Moreover, in the case of said (3), although the thickness is not specifically limited and the said primer layer should just set arbitrarily, A preferable minimum is 3 nm and a preferable upper limit is 125 nm.
In addition, the thickness of the said primer layer is the average value (nm) obtained by measuring arbitrary 10 points | pieces, for example by observing the cross section of the said primer layer with an electron microscope (SEM, TEM, STEM). is there. In the case of a very thin thickness, a high-magnification observation is recorded as a photograph and further magnified for measurement. When enlarged, the layer interface line is a very thin line so that it can be clearly seen as a boundary line. In that case, the center portion obtained by dividing the thick line width into two is measured as a boundary line.

The material constituting such a primer layer is not particularly limited as long as it has adhesiveness with the light transmissive substrate (1), and a material conventionally used as a primer layer of an optical laminate may be used. it can.
However, when considering the material of the primer layer for the conventional optical laminate, the refractive index of the primer layer is in the range of 1.47 to 1.63 when a material that also satisfies the adhesion and hardness is selected. Compared to the case where the layer thickness is not controlled, the optical layered body is preferable because the material selection range of the primer layer is very large.
In addition, since the refractive index (nf) of the optical function layer exhibits the effect by the interference in the above (1) and (2), the primer layer, the light transmissive substrate (1), the optical function layer, The closer the refractive index difference is, the better. In (3), the closer to the refractive index of the primer layer, the better from the viewpoint of suppressing the increase in the interface.

In the optical layered body, the primer layer is formed using a primer layer composition prepared by mixing and dispersing the above-described materials and, if necessary, a photopolymerization initiator and other components in a solvent. Can do.
The mixing and dispersing may be performed using a known apparatus such as a paint shaker, a bead mill, a kneader.

As the solvent, water is preferably used, and is preferably used in the form of an aqueous coating liquid such as an aqueous solution, an aqueous dispersion, or an emulsion. Further, some organic solvent may be included.
Examples of the organic solvent include alcohols (eg, methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol), ketones (eg, acetone, methyl ethyl ketone, methyl). Isobutyl ketone, cyclopentanone, cyclohexanone, heptanone, diisobutyl ketone, diethyl ketone), aliphatic hydrocarbon (eg, hexane, cyclohexane), halogenated hydrocarbon (eg, methylene chloride, chloroform, carbon tetrachloride), aromatic carbonization Hydrogen (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran) ), Ether alcohols (e.g., 1-methoxy-2-propanol), esters (e.g., methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate) and the like.

The other components are not particularly limited, and for example, leveling agent, organic or inorganic fine particles, photopolymerization initiator, thermal polymerization initiator, crosslinking agent, curing agent, polymerization accelerator, viscosity modifier, antistatic agent, oxidation Examples thereof include an inhibitor, an antifouling agent, a slip agent, a refractive index modifier, and a dispersant.

The primer layer composition preferably has a total solid content of 3 to 20%. If it is less than 3%, residual solvent may remain or whitening may occur. If it exceeds 20%, the viscosity of the composition for the primer layer is increased, the coatability is lowered, unevenness and streaks appear on the surface, and the desired film thickness may not be obtained. The total solid content is more preferably 4 to 10%.

Application of the primer layer composition to the polyester substrate can be carried out at any stage, but it is preferably carried out during the production process of the polyester substrate, and further before the orientation crystallization is completed. It is preferable to apply to a polyester substrate.
Here, the polyester base material before the crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in the longitudinal direction and the transverse direction. In the direction (low-stretch orientation orientation (biaxially stretched film before reorientation in the machine direction or transverse direction to complete orientation crystallization)). Especially, it is preferable to apply | coat the aqueous coating liquid of the said composition for primer layers to an unstretched film or the uniaxially stretched film orientated to one direction, and to perform longitudinal stretch and / or lateral stretch and heat setting as it is.
When the primer layer composition is applied to a polyester substrate, physical treatment such as corona surface treatment, flame treatment, plasma treatment or the like is performed on the polyester substrate surface as a pretreatment for improving the coating property, or It is preferred to use a chemically inert surfactant together with the primer layer composition.

As a method for applying the primer layer composition, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination. In addition, a coating film may be formed only in the single side | surface of a polyester base material as needed, and may be formed in both surfaces.

Further, as described above, the interference fringe prevention performance of the primer layer is manifested by setting the refractive index and thickness of the primer layer in the specific range.
The primer layer or hard coat layer having such a specific refractive index is obtained by adding high refractive index fine particles or low refractive index fine particles to the hard coat layer composition or primer layer composition described above. It is preferable to form using the composition which adjusted.

As the high refractive index fine particles, for example, metal oxide fine particles having a refractive index of 1.50 to 2.80 are preferably used. Specific examples of the metal oxide fine particles include titanium oxide (TiO ₂ , refractive index: 2.71), zirconium oxide (ZrO ₂ , refractive index: 2.10), cerium oxide (CeO ₂ , refraction). rate: 2.20), tin oxide (SnO _2, refractive index: 2.00), antimony tin oxide (ATO, refractive index: 1.75 to 1.95), indium tin oxide (ITO, the refractive index: 1.95 to 2.00), phosphorus tin compound (PTO, refractive index: 1.75 to 1.85), antimony oxide (Sb ₂ O ₅ , refractive index: 2.04), aluminum zinc oxide (AZO, Refractive index: 1.90 to 2.00), gallium zinc oxide (GZO, refractive index: 1.90 to 2.00) and zinc antimonate (ZnSb ₂ O ₆ , refractive index: 1.90 to 2.00) ) And the like. Among them, tin oxide (SnO ₂ ), antimony tin oxide (ATO), indium tin oxide (ITO), phosphorus tin compound (PTO), antimony oxide (Sb ₂ O ₅ ), aluminum zinc oxide (AZO), Gallium zinc oxide (GZO) and zinc antimonate (ZnSb ₂ O ₆ ) are conductive metal oxides, and can impart antistatic properties by controlling the diffusion state of fine particles and forming conductive paths. There are advantages.
As the low refractive index fine particles, for example, those having a refractive index of 1.20 to 1.45 are preferably used. As such low refractive index fine particles, fine particles used in conventionally known low refractive index layers can be used. For example, the above-described hollow silica fine particles, LiF (refractive index 1.39), MgF ₂ ( Metal fluoride such as magnesium fluoride, refractive index 1.38), AlF ₃ (refractive index 1.38), Na ₃ AlF ₆ (cryolite, refractive index 1.33) and NaMgF ₃ (refractive index 1.36). Compound fine particles.

The content of the high refractive index fine particles and the low refractive index fine particles is not particularly limited. For example, the weighted average of the refractive index values measured in advance of the cured resin component added to the hard coat layer composition Thus, the refractive index of the hard coat layer to be formed may be appropriately adjusted in relation to other components so as to satisfy the above-described relationship.

The hard coat layer is formed by applying the hard coat layer composition on the primer layer formed by the above-described method to form a hard coat layer coating film, and drying it as necessary. It can be formed by curing a coating film for a coat layer.
When the hard coat layer composition contains an ultraviolet curable resin, the primer layer composition contains an initiator used for curing the hard coat layer coating film. The adhesion between the coat layer and the primer layer can be obtained more reliably.

The optical layered body preferably has a hardness of HB or more and more preferably H or more in a pencil hardness test (load 4.9 N) according to JIS K5600-5-4 (1999).

The optical layered body preferably has a total light transmittance of 80% or more. If it is less than 80%, color reproducibility and visibility may be impaired when mounted on an image display device, and a desired contrast may not be obtained. The total light transmittance is more preferably 90% or more.
The total light transmittance can be measured by a method based on JIS K-7361 using a haze meter (manufactured by Murakami Color Research Laboratory, product number: HM-150).

The optical layered body preferably has a haze of 1% or less. If it exceeds 1%, desired optical characteristics cannot be obtained, and the visibility when the optical laminate is placed on the image display surface is lowered.
The haze can be measured by a method based on JIS K-7136 using a haze meter (manufactured by Murakami Color Research Laboratory, product number: HM-150).

When the optical functional layer is a hard coat layer, the optical laminate is formed on the light-transmitting substrate (1) using, for example, the hard coat layer composition described above. Can be manufactured. In the case where the optical functional layer has a structure in which a low refractive index layer is laminated on the hard coat layer, a hard coat layer is formed on the light transmissive substrate (1) by using the hard coat layer composition described above. After forming a layer, it can manufacture by forming a low-refractive-index layer on a hard-coat layer using the composition for low-refractive-index layers mentioned above.
About the formation method of the said composition for hard-coat layers and a hard-coat layer, the composition for low-refractive-index layers, and the formation method of a low-refractive-index layer, the material and method similar to having mentioned above are mentioned.

In the polarizing plate composite of the present invention, at least the light-transmitting substrate (2) having a birefringence in the plane and the polarizer (2) are laminated in this order from the backlight source side, and the image display device The polarizing plate is arranged and used on the backlight source side.
The light transmissive substrate (2) is not particularly limited as long as it has a birefringence in the surface, and examples thereof include the same as the light transmissive substrate (1) described above. Among them, a polyester base material that is advantageous in cost and mechanical strength is preferable. In the following description, the light-transmitting substrate (2) having a birefringence in the plane will be described as a polyester substrate (2).

In the polarizing plate, the refractive index (nx) in the direction in which the refractive index is large (slow axis direction) in the plane of the polyester substrate (2), and the direction (fast axis direction) orthogonal to the slow axis direction The difference nx−ny (hereinafter also referred to as Δn) from the refractive index (ny) is preferably 0.01 or more. When Δn is less than 0.01, the effect of improving transmittance may be reduced. On the other hand, the Δn is preferably 0.30 or less. If it exceeds 0.30, it becomes necessary to stretch the polyester base material excessively, so that the polyester base material is likely to be torn and torn, and the practicality as an industrial material may be remarkably lowered.
From the above viewpoint, the more preferable lower limit of Δn is 0.05, and the more preferable upper limit is 0.27. In addition, when said (DELTA) n exceeds 0.27, durability of the polyester base material (2) in a heat-and-moisture resistance test may be inferior. Since the durability in the heat and humidity resistance test is excellent, the more preferable upper limit of Δn is 0.25. By satisfying such Δn, a suitable improvement in light transmittance can be achieved.

In the present specification, whether or not the light-transmitting substrate has a birefringence in the plane is determined by Δn (nx−ny) ≧ 0.0005 at a refractive index of a wavelength of 550 nm. It is assumed that those having birefringence and those having Δn <0.0005 do not have birefringence. The birefringence can be measured by setting a measurement angle of 0 ° and a measurement wavelength of 552.1 nm using KOBRA-WR manufactured by Oji Scientific Instruments. At this time, for calculating the birefringence, the film thickness and the average refractive index are required. The film thickness can be measured using, for example, a micrometer (Digital Micrometer, manufactured by Mitutoyo Corporation) or an electric micrometer (produced by Anritsu Corporation). The average refractive index can be measured using an Abbe refractometer or an ellipsometer.
In addition, Δn of TD80UL-M (manufactured by Fuji Film Co., Ltd.) made of triacetyl cellulose and ZF16-100 (made by Nippon Zeon Co., Ltd.) made of cycloolefin polymer, which is generally known as an isotropic material, is determined by the above measuring method. These were 0.00007 and 0.00005, respectively, and were judged to have no birefringence (isotropic).
As another method for measuring birefringence, two polarizing plates are used to determine the orientation axis direction (major axis direction) of the light-transmitting substrate (2), and two axes perpendicular to the orientation axis direction are obtained. Can be obtained with an Abbe refractometer (NAR-4T manufactured by Atago Co., Ltd.), and a black vinyl tape (for example, Yamato vinyl tape No200-38-21 38 mm width) is attached to the back surface. Then, using a spectrophotometer (V7100 type, automatic absolute reflectance measurement unit, VAR-7010, manufactured by JASCO Corporation), polarization measurement: S-polarized light, with the slow axis parallel to S-polarized light And when the fast axis is parallel, the 5 degree reflectivity is measured, and the slow axis and the fast axis are expressed by the following formula (1) showing the relationship between the reflectivity (R) and the refractive index (n). The refractive index (nx, ny) of each wavelength can also be calculated .
R (%) = (1-n) ² / (1 + n) ² formula (1)

The average refractive index can be measured using an Abbe refractometer or an ellipsometer, and the refractive index nz in the thickness direction of the light transmissive substrate (2) is nx, It can be calculated from the following formula (2) using ny.
Average refractive index N = (nx + ny + nz) / 3 Formula (2)

Here, a calculation method of nx, ny, and nz will be described with a specific example.
Nx is the refractive index in the slow axis direction of the light transmissive substrate (2), ny is the refractive index in the fast axis direction of the light transmissive substrate (2), and nz is the light transmissive substrate. This is the refractive index in the thickness direction of (2).
(Calculation of three-dimensional refractive index wavelength dispersion)
First, a calculation method of three-dimensional refractive index wavelength dispersion will be specifically described by taking a cycloolefin polymer as an example.
The average refractive index wavelength dispersion of a cycloolefin polymer film having no in-plane birefringence was measured using an ellipsometer (UVISEL Horiba, Ltd.), and the results are shown in FIG. From this measurement result, the average refractive index wavelength dispersion of the cycloolefin polymer film having no in-plane birefringence was defined as the refractive index wavelength dispersion of nx, ny, and nz.
The film was uniaxially stretched at a free temperature at a stretching temperature of 155 ° C. to obtain a film having a birefringence in the plane. The film thickness was 100 μm. This free-end uniaxially stretched film was measured with a birefringence meter (KOBRA-21ADH, Oji Scientific Instruments) with four retardation values (447.6 nm, 547.0 nm, 630.6 nm) at an incident angle of 0 ° and 40 °. 743.4 nm).
Based on the average refractive index (N) and retardation value at each wavelength, the three-dimensional refractive index using the Couchy or Sellmeier equation, etc., using the three-dimensional chromatic dispersion calculation software attached to the birefringence meter. The chromatic dispersion was calculated and the result is shown in FIG. In FIG. 2, ny is shown substantially overlapping with nz. From this result, a three-dimensional refractive index wavelength dispersion of a cycloolefin polymer having an in-plane birefringence was obtained.
(Calculation of refractive indices nx, ny and nz using a spectrophotometer)
Taking polyethylene terephthalate as an example, a method of calculating refractive indexes nx, ny, and nz using a spectrophotometer will be specifically described.
The average refractive index wavelength dispersion of polyethylene terephthalate having no in-plane birefringence was performed in the same manner as the above-described method for calculating the three-dimensional refractive index wavelength dispersion.
The refractive index wavelength dispersion (nx, ny) of polyethylene terephthalate having a birefringence in the plane was calculated using a spectrophotometer (V7100 type, automatic absolute reflectance measurement unit VAR-7010, manufactured by JASCO Corporation). Polarization measurement: S-polarized light after a black vinyl tape (for example, Yamato vinyl tape No200-38-21 38 mm width) having a width larger than the measurement spot area is pasted on the surface opposite to the measurement surface to prevent back surface reflection. Then, the 5-degree spectral reflectance was measured when the alignment axis of the light-transmitting substrate (2) was installed in parallel and when the axis orthogonal to the alignment axis was installed in parallel. The results are shown in FIG. The refractive index wavelength dispersion (nx, ny) was calculated from the above formula (1) showing the relationship between the reflectance (R) and the refractive index (n). A direction indicating a larger reflectance (refractive index calculated by the above equation (1)) is nx (also referred to as a slow axis), and a smaller reflectance (refractive index calculated by the above equation (1)) is indicated. The direction was ny (also called fast axis). Here, the orientation axis is a state in which a film having a birefringence in-plane is sandwiched between two polarizing plates placed in a crossed Nicol state on a light source, the film is rotated, and light leakage is minimized. In this case, the transmission axis of the polarizing plate or the same direction as the absorption axis can be used as the orientation axis of the film. The refractive index nz can be calculated from the average refractive index (N) and the above equation (2).

The material constituting the polyester substrate (2) is not particularly limited as long as it satisfies the above-described Δn, but from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Examples thereof include linear saturated polyesters to be synthesized. Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene naphthalate (polyethylene-2,6-naphthalate, polyethylene-1,4-naphthalate). , Polyethylene-1,5-naphthalate, polyethylene-2,7-naphthalate, polyethylene-2,3-naphthalate) and the like. The polyester used for the polyester substrate (2) may be a copolymer of these polyesters, and the polyester is the main component (for example, a component of 80 mol% or more), and a small proportion (for example, 20 mol% or less). It may be blended with other types of resins. Polyethylene terephthalate or polyethylene naphthalate is particularly preferable as the polyester because of good balance between mechanical properties and optical properties. In particular, it is preferably made of polyethylene terephthalate (PET). This is because polyethylene terephthalate is highly versatile and easily available. In the present invention, a polarizing plate having excellent light transmittance can be obtained even with a highly versatile film such as PET. Furthermore, PET is excellent in transparency, heat or mechanical properties, Δn can be controlled by stretching, and has a large intrinsic birefringence, so that it can have a birefringence relatively easily.

The method for obtaining the polyester base material (2) is not particularly limited as long as it satisfies the above-described Δn. For example, the polyester, such as the above-mentioned PET, is melted and extruded into a sheet shape and is unstretched. There is a method in which the polyester is subjected to heat treatment after transverse stretching using a tenter or the like at a temperature equal to or higher than the glass transition temperature.
The transverse stretching temperature is preferably 80 to 130 ° C, more preferably 90 to 120 ° C. Further, the transverse draw ratio is preferably 2.5 to 6.0 times, more preferably 3.0 to 5.5 times. When the transverse draw ratio exceeds 6.0 times, the transparency of the resulting polyester base material tends to be lowered, and when the transverse draw ratio is less than 2.5 times, the draw tension becomes small. The birefringence of the substrate may be reduced.
In the present invention, the unstretched polyester is subjected to transverse stretching under the above conditions using a biaxial stretching test apparatus, and then stretched in the flow direction with respect to the transverse stretching (hereinafter also referred to as longitudinal stretching). Also good. In this case, the longitudinal stretching preferably has a stretching ratio of 2 times or less. When the draw ratio of the above-mentioned longitudinal stretching exceeds twice, the value of Δn may not be within the preferred range described above.
The treatment temperature during the heat treatment is preferably 100 to 250 ° C, more preferably 180 to 245 ° C.

As thickness of the said polyester base material (2), it is preferable to exist in the range of 5-500 micrometers. If it is less than 5 μm, tearing, tearing and the like are likely to occur, and the utility as an industrial material may be significantly reduced. On the other hand, if it exceeds 500 μm, the polyester base material (2) is very rigid, the flexibility specific to the polymer film is lowered, and the practicality as an industrial material is also lowered, which is not preferable. The minimum with more preferable thickness of the said polyester base material (2) is 10 micrometers, a more preferable upper limit is 300 micrometers, and a still more preferable upper limit is 150 micrometers.

The polyester base material (2) preferably has a transmittance in the visible light region of 80% or more, and more preferably 84% or more. In addition, the said transmittance | permeability can be measured by JISK7361-1 (The test method of the total light transmittance of a plastic-transparent material).

In the present invention, the polyester substrate (2) is subjected to surface treatment such as saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, and flame treatment without departing from the spirit of the present invention. You may go.

The polarizer (2) is not particularly limited, and for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, etc. dyed and stretched with iodine or the like is used. Can do.

In the polarizing plate, the light-transmitting substrate (2) and the polarizer (2) are a fast axis that is a direction in which the refractive index of the light-transmitting substrate (2) is small and the polarizer (2). The angle between the transmission axis and the transmission axis is 0 ° ± 30 ° or 90 ° ± 30 °. Since the light transmissive substrate (2) and the polarizer (2) are arranged as described above, the polarizing plate can have excellent light transmittance as described above. That is, when the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is out of the above range, specifically, when it is less than 45 ° ± 15 °. The light transmittance of the polarizing plate is extremely low. This is due to the following reason.
In a polarizing plate provided with a polarization separation film between the light source and the polarizer (2), the direction of the polarization axis of the light transmitted through the transmission axis of the polarizer (2) and the polarized light transmitted through the polarization separation film are usually obtained. It is installed so as to coincide with the direction of the polarization axis of the light. For this reason, a light transmissive substrate (2) having a birefringence in-plane is installed between the polarizer (2) and the polarization separation film, and the light transmissive substrate (2) is advanced. When the angle formed between the phase axis and the transmission axis of the polarizer (2) is less than 45 ° ± 15 °, the polarization axis of the polarized light transmitted through the polarization separation film changes, and It is absorbed by the absorption axis of the child (2), and the light transmittance of the polarizing plate becomes extremely low.

In the polarizing plate, the light transmissive substrate (2) and the polarizer (2) are formed by a fast axis of the light transmissive substrate (2) and a transmission axis of the polarizer (2). The layers are preferably laminated so that the angle is 0 ° ± 15 ° or 90 ° ± 15 °. When the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is in the above range, the light transmittance of the polarizing plate is extremely good.

In the polarizing plate, the light transmissive substrate (2) and the polarizer (2) have an angle formed by a fast axis of the light transmissive substrate (2) and a transmission axis of the polarizer. It is more preferable that the layers are laminated so as to be 0 ° ± 5 °. When the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is in the above range, the light transmittance of the polarizing plate is extremely good. This is because when the angle between the fast axis, which is the direction in which the refractive index of the light-transmitting substrate (2) is small, and the transmission axis of the polarizer (2) is in the above range, polarized light is This is because the reflectance when entering the light transmissive substrate (2) can be reduced.
The reason is as follows.
That is, when the polarized light transmitted through the polarization separation film enters the polarizing plate, the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is 0 °. Even if it is 90 °, the polarized light transmitted through the polarization separation film passes through the light-transmitting substrate (2) while maintaining its vibration direction. However, when this light enters the light-transmitting substrate (2) from the air interface, reflection occurs according to the following equation. Here, in the following formula, ρ represents the reflectance, and na represents the in-plane refractive index of the light-transmitting base material (2) in the same direction as the vibration direction of light.
ρ = (1-na) ² / (1 + na) ²
The transmittance τ of the polarizing plate can be obtained by the following equation. Since the material is the same, the absorption rate α is the same value. The rate ρ may be reduced.
τ = 1−ρ−α
That is, the light-transmitting base material (2) having a birefringence in the plane and the polarizer (2) have a fast axis that is a direction in which the refractive index of the light-transmitting base material (2) is small. When the angle formed by the transmission axis of the polarizer (2) is 0 °, the light is caused by the difference between the smallest refractive index and the refractive index of air in the plane of the light transmissive substrate (2). Since reflection occurs, the reflectance can be minimized and the transmittance can be increased. On the other hand, the light-transmitting substrate (2) having a birefringence in the plane and the polarizer (2) have a fast axis in a direction in which the refractive index of the light-transmitting substrate (2) is small. When the angle formed by the transmission axis of the polarizer (2) is 90 °, the light is caused by the difference between the largest refractive index and the refractive index of air in the plane of the light transmissive substrate (2). Since reflection occurs, the reflectance becomes the largest, and as a result, the transmittance decreases.

Furthermore, in the polarizing plate, the refractive index (nx) in the slow axis direction, which is the direction in which the refractive index of the light transmissive substrate (2) having a birefringence index in the plane is large, and the slow axis direction, The refractive index (ny) in the fast axis direction, which is an orthogonal direction, and the average refractive index (N) of the light-transmitting substrate (2) have a relationship of the following formula, and the fast axis: When the angle formed by the transmission axis of the polarizer and the polarizer (2) is 0 ° ± 2 °, the transmittance can be improved more than when the light-transmitting substrate (2) is used as isotropic material. preferable.
nx>N> ny
The polarizing plate has the light-transmitting substrate (2) on the surface opposite to the side on which the polarizer (2) of the light-transmitting substrate (2) having birefringence is laminated. A low refractive index layer having a refractive index smaller than the refractive index ny in the fast axis direction may be provided. The low refractive index layer is not particularly limited as long as the refractive index is smaller than the refractive index ny in the fast axis direction of the light transmissive substrate (2), and is made of a conventionally known material. Is mentioned.

In the polarizing plate, polarized light is incident on a light-transmitting substrate (2) having a birefringence in the plane.
In the polarizing plate, the polarized light is not particularly limited. For example, light generated from a backlight light source of an image display device such as a liquid crystal display device is preferably transmitted through a polarization separation film and polarized. It is mentioned in. A conventionally known polarized light source may be used as the light source of the polarizing plate.
The polarization separation film is a member having a polarization separation function of transmitting only a specific polarization component and reflecting other polarization components of the light emitted from the backlight light source. When the polarizing plate is used in a liquid crystal display device, the polarizing plate is configured between the liquid crystal cell and the polarization separation film, and the polarizing plate selectively transmits only a specific polarization component. By selectively reflecting and reusing a polarized light component other than a specific polarized light component (a polarized light component transmitted through the polarizing plate) using a polarized light separating film, the amount of light passing through the polarizing plate is increased, The brightness of the display screen of the liquid crystal display device can be improved.
As the polarization separation film, a general film used in a liquid crystal display device can be used. Moreover, you may use a commercial item as a polarized light separation film, for example, the DBEF series by Sumitomo 3M can be used.

In the polarizing plate, the light transmissive substrate (2) and the polarizer (2) have a specific relationship between the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2). Thus, the light transmittance is improved.

The polarizing plate comprises a light transmissive substrate (2) having a birefringence in the plane and a polarizer (2), and a light transmissive substrate (2 having a birefringence in the plane). ) In which the refractive index is small and the angle formed by the transmission axis of the polarizer is 0 ° ± 30 ° or 90 ° ± 30 °. .
It is preferable to laminate | stack the light-transmitting base material (2) which has a birefringence in the said surface, and the said polarizer (2) through a well-known adhesive agent.

The method for producing a polarizing plate composite of the present invention provided with the optical laminate and the polarizing plate is also one aspect of the present invention.
That is, the method for producing a polarizing plate composite of the present invention has an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in the surface, and is disposed on the surface of the image display device. The optical layered body used as a light source, and at least a light-transmitting substrate (2) having a birefringence in the plane and a polarizer are laminated in this order from the backlight source side, and the back of the image display device A polarizing plate composite having a polarizing plate arranged and used on the light source side, the slow axis being a direction in which the refractive index of the light transmissive substrate (1) is large, and the image display The step of arranging the optical laminate so that the vertical direction of the display screen of the apparatus is parallel, the light-transmitting base material (2), and the polarizer are the light-transmitting base material (2). The angle formed by the fast axis, which is the direction in which the refractive index of the light is small, and the transmission axis of the polarizer is 0 ° ± It has the process of laminating | stacking so that it may become 30 degrees or 90 degrees +/- 30 degrees.
The method mentioned above is mentioned as a manufacturing method of the said optical laminated body and a polarizing plate.

An optical laminate having an optical functional layer on one surface of a light-transmitting base material (1) having a birefringence index in the plane is provided on the polarizer (1), and is provided on the surface of the image display device. A polarizing plate to be used and a light-transmitting base material (2) having a birefringence index in the plane and a polarizer (2) are laminated in this order from the backlight light source side, and the image display device A polarizing plate set having a polarizing plate used on the backlight source side of the optical laminate, wherein the optical laminate (1) and the polarizer (1) are refractive indexes of the light-transmitting substrate. The slow axis, which is a direction in which the refractive index of the light transmissive substrate (1) is large, is arranged so that the slow axis, which is the direction in which the refractive index is large, and the absorption axis of the polarizer (1) are perpendicular to each other. Are arranged in parallel with the vertical direction of the display screen of the image display device, and the light transmissive substrate (2) is biased. The light-transmitting base material (2) and the polarizer (2) are fast axes in which the refractive index of the light-transmitting base material (2) is small. And a polarizing plate set in which the angle between the polarizer (2) and the transmission axis of the polarizer (2) is 0 ° ± 30 ° or 90 ° ± 30 °. One.

As a polarizing plate which has the above-mentioned optical layered product in the polarizing plate set of the present invention, the above-mentioned translucent base material (2), and a polarizer (2), and is arranged on the back light source side, the above-mentioned of the present invention. The same thing as the optical laminated body and polarizing plate in a polarizing plate composite is mentioned.
In the polarizing plate set of the present invention, the light-transmitting substrate (1) having a birefringence in the plane preferably has a retardation of 3000 nm or more for the same reason as the optical laminate of the present invention described above. The difference (nx−ny) between the refractive index (nx) in the slow axis direction, which is the direction in which the refractive index is large, and the refractive index (ny) in the fast axis direction, which is the direction orthogonal to the slow axis direction. , 0.05 or more is preferable.
Moreover, the polarizing plate set of this invention has a primer layer between the said light-transmissive base material (1) and an optical function layer for the same reason as the optical laminated body mentioned above, The thickness of the said primer layer is It is preferable that the material is appropriately selected according to the above (1) to (3).

It does not specifically limit as said polarizer (1), For example, the thing similar to the polarizing plate (2) demonstrated in the polarizing plate composite mentioned above is mentioned.
In the laminating process of the polarizer (1) and the optical laminate, it is preferable to saponify the light-transmitting substrate. By the saponification treatment, the adhesiveness is improved and an antistatic effect can be obtained.

In the polarizing plate set of the present invention, the light transmissive substrate (1) and the polarizer (1) are a slow axis in which the refractive index of the light transmissive substrate (1) is large, and the above It arrange | positions so that the absorption axis of a polarizer (1) may become perpendicular | vertical. In the polarizing plate set of the present invention, the light transmissive substrate (1) and the polarizer (1) are arranged as described above, and the light transmissive substrate (1) has a larger refractive index. Since the slow axis is set in parallel with the vertical direction of the display screen of the image display device, the antireflection performance and the bright contrast are excellent as in the optical laminate described above.
The “light transmissive substrate (1) and the polarizer (1) are a slow axis in which the refractive index of the light transmissive substrate (1) is large, and the polarizer (1). ”Is perpendicular to the absorption axis of“) ”means that the angle between the slow axis of the light-transmitting substrate (1) and the absorption axis of the polarizer (1) is 90 ° ± 40. It means a state in which the light transmissive substrate (1) and the polarizer (1) are installed so as to be in the range of °.

In such a polarizing plate set of the present invention, the light transmissive substrate (1) and the polarizer (1) of the optical laminate are arranged in a direction in which the refractive index of the light transmissive substrate (1) is large. It can be manufactured by arranging so that a certain slow axis and the absorption axis of the polarizer (1) are perpendicular to each other, and it is a slow direction in which the refractive index of the light-transmitting substrate (1) is large. The phase axis is arranged in parallel with the vertical direction of the display screen of the image display device.

The above-mentioned polarizing plate composite of the present invention or an image display device comprising the polarizing plate set of the present invention is also one aspect of the present invention.
The image display device of the present invention may be an image display device such as LCD, PDP, FED, ELD (organic EL, inorganic EL), CRT, tablet PC, touch panel, electronic paper, and the like. Is preferred.

The LCD, which is a typical example of the above, includes a transmissive display body and a light source device that irradiates the transmissive display body from the back. When the image display device of the present invention is an LCD, the optical laminate or the polarizing plate is formed on the surface of the transmissive display.

When the image display device of the present invention is a liquid crystal display device having the polarizing plate composite of the present invention or the polarizing plate set of the present invention, the light source of the light source device is the polarizing plate composite of the present invention or the polarizing plate set of the present invention. Irradiated from below. A retardation plate may be inserted between the liquid crystal display element and the polarizing plate composite of the present invention or the polarizing plate set of the present invention. An adhesive layer may be provided between the layers of the liquid crystal display device as necessary.

The PDP is disposed with a surface glass substrate having an electrode formed on the surface and a discharge gas sealed between the surface glass substrate, the electrode and minute grooves formed on the surface, and red in the grooves. And a rear glass substrate on which green and blue phosphor layers are formed. When the image display device of the present invention is a PDP, the surface of the surface glass substrate or the polarizing plate composite of the present invention described above on the front plate (glass substrate or film substrate) or the polarizing plate set of the present invention. It also includes an optical laminate.

The image display device of the present invention is an ELD device that emits light when a voltage is applied, such as zinc sulfide or a diamine substance: a phosphor is deposited on a glass substrate, and the voltage applied to the substrate is controlled. It may be an image display device such as a CRT that generates an image visible to human eyes. In this case, the optical laminate in the polarizing plate composite of the present invention or the polarizing plate set of the present invention described above is provided on the outermost surface of each display device as described above or the surface of the front plate.

Here, in the case where the present invention is a liquid crystal display device having a polarizing plate composite or a polarizing plate set, the backlight light source in the liquid crystal display device is not particularly limited, but is preferably a white light emitting diode (white LED). The image display device of the present invention is preferably a VA mode or IPS mode liquid crystal display device including a white light emitting diode as a backlight light source.
The white LED is an element that emits white by combining a phosphor with a phosphor system, that is, a light emitting diode that emits blue light or ultraviolet light using a compound semiconductor. In particular, white light-emitting diodes, which consist of light-emitting elements that combine blue light-emitting diodes using compound semiconductors with yttrium, aluminum, and garnet yellow phosphors, have a continuous and broad emission spectrum, so they have anti-reflection performance. In addition, it is effective for improving the contrast of a bright place and is excellent in luminous efficiency, so that it is suitable as the backlight light source in the present invention. Further, since white LEDs with low power consumption can be widely used, it is possible to achieve an energy saving effect.
The VA (Vertical Alignment) mode refers to a dark display in which liquid crystal molecules are aligned so as to be perpendicular to the substrate of the liquid crystal cell when no voltage is applied, and the liquid crystal molecules are collapsed when a voltage is applied. This is an operation mode showing bright display.
The IPS (In-Plane Switching) mode is a method in which display is performed by rotating the liquid crystal within the substrate surface by a horizontal electric field applied to a pair of comb electrodes provided on one substrate of the liquid crystal cell. is there.
The image display device using the polarizing plate composite or the polarizing plate set is preferably in a VA mode or an IPS mode including a white light emitting diode as a backlight light source for the following reason.
That is, the image display device of the present invention can reduce the reflection of the light (S-polarized light) that vibrates in the left-right direction with a high ratio of incidence on the display screen from the optical laminate or the polarizing plate. A lot of S-polarized light is transmitted. Normally, these transmitted S-polarized light is absorbed inside the display device, but there is very little light returning to the observer side. In the VA mode or the IPS mode, the absorption axis of the polarizer installed on the observer side of the liquid crystal cell is in the horizontal direction with respect to the display screen, so the S-polarized light transmitted through the optical laminate or the polarizing plate is absorbed. This is because the light returning to the observer side can be reduced.

In any case, the image display device of the present invention can be used for display display of a television, a computer, electronic paper, a touch panel, a tablet PC, or the like. In particular, it can be suitably used for the surface of a high-definition image display such as a CRT, liquid crystal panel (LCD), PDP, ELD, FED, touch panel, etc. Among them, it can be suitably used for an LCD.

Moreover, the manufacturing method of the image display apparatus provided with the optical laminated body which has an optical function layer on one surface of the transparent base material (1) which has a birefringence index in a surface is also one of this invention.
That is, the manufacturing method of the image display device of the present invention has an optical functional layer on one surface of the light-transmitting substrate (1) having a birefringence in the surface, and is disposed on the surface of the image display device. The optical layered body used, and at least a light-transmitting base material (2) having a birefringence in-plane and a polarizer (2) are laminated in this order, and arranged on the backlight source side of the image display device. A method of manufacturing an image display device provided with a polarizing plate used in the above-described method, wherein the light transmissive substrate (1) has a slow axis in which the refractive index is large, and the vertical direction of the display screen of the image display device. The step of disposing the optical laminate so that the light transmitting substrate (2) and the polarizer are arranged in a direction in which the refractive index of the light transmitting substrate (2) is small. The angle formed by a certain fast axis and the transmission axis of the polarizer is 0 ° ± 30 ° or 90 ° ± 30 °. It characterized by having a step of sea urchin laminated.
In the method for producing an image display device of the present invention, as the polarizing plate having the optical layered body and the light transmissive substrate (2) and the polarizer (2), the optical layered body in the polarizing plate composite of the present invention described above. And the thing similar to a polarizing plate is mentioned.
Further, the optical laminated body is arranged so that the slow axis, which is the direction in which the refractive index of the light-transmitting substrate (1) is large, and the vertical direction of the display screen of the image display device are parallel to each other. “Yes” means that the optical layered body is arranged so that an angle formed by the slow axis and the vertical direction of the display screen is in a range of 0 ° ± 40 °.

The above-described image display device of the present invention has excellent antireflection performance and bright place contrast, and improved visibility. Such a visibility improving method by the image display apparatus of the present invention is also one aspect of the present invention.
That is, the method for improving the visibility of the image display device of the present invention has an optical functional layer on one surface of the light-transmitting substrate (1) having a birefringence in the surface, and is provided on the surface of the image display device. An optical layered body that is disposed and used, and at least a light-transmitting base material (2) having a birefringence index in the plane and a polarizer (2) are laminated in this order, on the backlight light source side of the image display device A method for improving the visibility of an image display device provided with a polarizing plate arranged and used, the slow axis being a direction in which the refractive index of the light-transmitting substrate (1) is large, and the display of the image display device The optical laminate is arranged so that the vertical direction of the screen is parallel, and the light-transmitting substrate (2) and the polarizer (2) are bonded to the light-transmitting substrate (2). The angle formed by the fast axis, which is the direction in which the refractive index is small, and the transmission axis of the polarizer (2) is 0 ° ± 3 It is characterized by being laminated so as to be 0 ° or 90 ° ± 30 °.
In the method for improving the visibility of the image display device of the present invention, the optical laminate, the light-transmitting substrate (2), and the polarizing plate having the polarizer (2) are the optical components in the polarizing plate composite of the present invention described above. The same thing as a laminated body and a polarizing plate is mentioned, Moreover, as said image display apparatus, the thing similar to the image display apparatus of this invention mentioned above is mentioned.
In addition, the above-mentioned “position the optical laminate so that the slow axis, which is the direction in which the refractive index of the light-transmitting substrate is large, and the vertical direction of the display screen of the image display device are parallel” Means that the optical layered body is arranged so that an angle formed by the slow axis and the vertical direction of the display screen is in a range of 0 ° ± 40 °.

Since the polarizing plate composite and the polarizing plate set of the present invention have the above-described configuration, a light-transmitting substrate having a birefringence in a plane such as a polyester film is used as an optical laminate and a polarizing plate. Even if it is used, an image display device excellent in antireflection performance and bright place contrast can be obtained, and further, the light transmittance is also excellent.
For this reason, the polarizing plate composite and polarizing plate set of the present invention include a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), It can be suitably applied to electronic paper, a touch panel, a tablet PC, and the like, and in particular, can be suitably applied to an LCD.

It is a graph which shows the average refractive index wavelength dispersion of the cycloolefin polymer film which does not have a birefringence in a surface. It is a graph which shows the three-dimensional refractive index wavelength dispersion of the cycloolefin polymer film which has birefringence in a surface. It is a graph which shows the 5-degree reflectivity of nx and ny measured with the spectrophotometer. It is the spectrum of the light source used in the Example etc. It is a schematic diagram which shows the laminated constitution of the polarizing plate in an Example etc. It is a graph which shows the refractive index wavelength dispersion of the protective film used in the Example etc. It is a graph which shows the refractive index and extinction coefficient of the polarizer used in the Example etc.

(Photometric contrast evaluation method)
On the polarizing element on the observer side of the liquid crystal monitor (FLATORON IPS226V (manufactured by LG Electronics Japan)) so that the relationship between the S-polarized light at the time of reflectance measurement and the fast axis of the light-transmitting substrate is the same. The optical laminate was placed so that the optical functional layer was on the observer side, and the bright spot contrast of the display screen was visually evaluated at a peripheral illuminance of 400 lux (light spot).
Specifically, the photopic contrast is expressed by the following equation, and since the change rate of the photopic white luminance is generally small and the photopic black luminance change rate is large, the photopic contrast is governed by the photopic black luminance. Further, since the original black luminance of the panel is small and negligible compared with the photopic black luminance, the blackness (photopic black luminance) was evaluated in the following manner to substantially evaluate the photopic contrast.
That is, for two types of liquid crystal monitors having different angles between the S-polarized light and the fast axis of the light-transmitting substrate, one is the liquid crystal monitor A, the other is the liquid crystal monitor B, and the liquid crystal monitors A and B are arranged. Subject performs a sensory evaluation (visually observe a black-displayed LCD monitor from a position 50 to 60 cm away and evaluate which one looks black) When the number of people is less than 12, that is, when the number is 11 or less, the evaluation is inferior. In addition, the angle which installs an optical laminated body to liquid crystal monitor A and B is evaluating by swinging an angle suitably for every Example and a comparative example. In addition, when 13 or more subjects replied that they were black, they were considered particularly excellent.
Light place contrast: CR = LW / LB
Brightness white brightness (LW): Brightness when the display device displays white in a bright place with ambient light (peripheral illuminance 400 lux) Bright spot black brightness (LB): Bright place with ambient light (ambient illuminance 400) (Lux)) Luminance when the display device is displayed in black

(Reflectance measurement method)
A black vinyl tape (Yamato Vinyl Tape No200-38-21 38 mm wide was applied to the side opposite to the measurement layer, the side where the optical functional layer of the optical laminate was provided, and then the spectrophotometer (V7100, automatic absolute Using a reflectance measurement unit VAR-7010 manufactured by JASCO Corporation, polarization measurement: the case where the slow axis of the light-transmitting substrate (1) is set in parallel to the S-polarized light, and the fast axis is parallel. 5 degree reflectivity with the case where it installed in was measured.

(Evaluation of Nijimura)
In each of the examples, comparative examples, and reference examples, the liquid crystal monitor on which the optical layered body was installed for the bright place contrast evaluation was visually observed and polarized sunglasses from a position 50 to 60 cm away from the front and oblique directions (about 50 °). The display image was observed over and evaluated for Nijimura.
FIG. 4 shows a backlight light source spectrum of the liquid crystal monitor used.

(Measurement of retardation)
The retardation of the light transmissive substrate (1) was measured as follows.
First, the stretched light transmissive substrate (1) is obtained by using two polarizing plates to determine the orientation axis direction of the light transmissive substrate (1), and two axes orthogonal to the orientation axis direction. The refractive index (nx, ny) with respect to a wavelength of 590 nm was determined by an Abbe refractometer (NAR-4T manufactured by Atago Co., Ltd.). Here, an axis showing a larger refractive index is defined as a slow axis. The thickness d (nm) of the light-transmitting substrate was measured using an electric micrometer (manufactured by Anritsu), and the unit was converted to nm. Retardation was calculated from the product of refractive index difference (nx−ny) and film thickness d (nm).

(Measurement of refractive index)
It measured using the ellipsometer (made by UVISEL Horiba Ltd.).

(Example 1, Comparative Example 1)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film is preheated at 120 ° C. for 1 minute with a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. The film was stretched at a stretching ratio of 1.5 times in the direction of 90 degrees, and light transmittance of nx = 1.70, ny = 1.60, (nx-ny) = 0.10, film thickness 120 μm, retardation = 12000 nm. A substrate was obtained.
Next, as an optical functional layer, pentaerythritol triacrylate (PETA) is dissolved in 30% by mass in MIBK solvent, and a photopolymerization initiator (Irg184, manufactured by BASF) is added at 5% by mass with respect to the solid content. The layer composition was coated with a bar coater so that the film thickness after drying was 5 μm to form a coating film.
Next, the formed coating film is heated at 70 ° C. for 1 minute, the solvent is removed, and the coated surface is fixed by irradiating with ultraviolet rays, and has an optical functional layer having a refractive index (nf) of 1.53. Got the body. The reflectance of the optical laminate of Example 1 measured by setting the S-polarized light and the light-transmitting base material in parallel with the fast axis (the angle between the S-polarized light and the light-transmitting base material being 0 °). Was 4.45%, and was measured by setting the S-polarized light and the slow axis of the light-transmitting substrate in parallel (the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 90 °). The reflectance of Comparative Example 1 was 4.73%, and the optical laminate of Example 1 was superior in antireflection performance.
In addition, on the polarizing element on the viewer side of the liquid crystal monitor (FLATORON IPS226V (manufactured by LG Electronics Japan)) so that the relationship between the S-polarized light at the time of reflectance measurement and the fast axis of the light-transmitting substrate is the same. In addition, the optical laminate was placed so that the optical functional layer was on the observer side, and the bright spot contrast of the display screen was visually evaluated at an ambient illuminance of 400 lux (light spot).
In the case of Example 1, the S-polarized light that vibrates in the left-right direction with respect to the display screen having a high incidence on the display screen is parallel to the fast axis of the light-transmitting substrate (the slow axis of the light-transmitting substrate) Is parallel to the vertical direction of the display screen, that is, the angle between the slow axis of the light-transmitting substrate and the vertical direction of the display screen is 0 °). The slow axis of the light-transmitting substrate was set in parallel (the slow axis of the light-transmitting substrate and the vertical angle of the display screen were 90 °) and evaluated. As a result, the liquid crystal monitor A using the optical laminate of Example 1 was particularly superior in the bright contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 1. Moreover, the liquid crystal monitor A using the optical laminated body of Example 1 was in a state in which there was no azimuth irregularity and the visibility improvement was extremely improved. On the other hand, the liquid crystal monitor B using the optical laminated body of Comparative Example 1 does not show Nizimura, but is inferior to the bright place contrast as compared with the liquid crystal monitor A using the optical laminated body of Example 1, and has antireflection performance. Was inferior.

(Example 2, comparative example 2)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute with a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. The film is stretched at a stretching ratio of 1.8 times in the direction of the degree, nx = 1.68, ny = 1.62, (nx-ny) = 0.06, film thickness 80 μm, retardation = 4800 nm. The material was obtained.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. Using the obtained optical laminate, the reflectance was measured in the same manner as in Example 1 (the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 0 °), and the contrast in the bright place was evaluated. The reflectance of the optical layered body of Example 2 is 4.46%, and the S-polarized light is parallel to the slow axis of the light-transmitting substrate (the angle between the S-polarized light and the fast axis of the light-transmitting substrate is The reflectivity of the optical laminate of Comparative Example 2 measured at 90 ° was 4.63%, and the optical laminate of Example 2 was superior in antireflection performance.
Further, the liquid crystal monitor A using the optical laminate of Example 2 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 2. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 2 was in a state where there was no azimuth and the visibility was extremely improved. On the other hand, the liquid crystal monitor B using the optical laminate of Comparative Example 2 was inferior in bright place contrast as compared with the liquid crystal monitor A using the optical laminate of Example 2 although no azimuth was observed. .

(Example 3, Comparative Example 3)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. A primer layer resin composition comprising 28.0 parts by mass of an aqueous dispersion and 72.0 parts by mass of water was uniformly applied by a roll coater. Next, this coated film was dried at 95 ° C., and stretched at a stretch ratio of 1.5 times in the direction of 90 degrees with respect to the previous stretching direction, nx = 1.70, ny = 1.60, (nx− ny) = 0.10, a film thickness of 120 μm, and a retardation = 12000 nm on a film, a light transmissive substrate having a refractive index of 1.56 and a primer layer of a film thickness of 100 nm was obtained.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. Using the obtained optical laminate, the reflectance was measured in the same manner as in Example 1 (the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 0 °), and the contrast in the bright place was evaluated. The reflectance of the optical layered body of Example 3 is 4.36%, and the S-polarized light and the slow axis of the light-transmitting substrate are parallel (the angle between the S-polarized light and the fast axis of the light-transmitting substrate is The reflectance of the optical laminated body of Comparative Example 3 measured by installing at 90 ° was 4.48%, and the optical laminated body of Example 3 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 3 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 3. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 3 was in a state in which there was no ridiculous and the visibility improvement was extremely improved. On the other hand, the liquid crystal monitor B using the optical laminate of Comparative Example 3 was inferior in bright place contrast as compared with the liquid crystal monitor A using the optical laminate of Example 3 although no azimuth was observed. .

(Example 4, comparative example 4)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute with a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. to a stretch ratio of 4.0 times. A primer layer resin composition comprising 28.0 parts by mass of an aqueous dispersion and 72.0 parts by mass of water was uniformly applied by a roll coater. Next, the coated film was dried at 95 ° C., and stretched at a stretching ratio of 1.8 times in the direction of 90 degrees from the previous stretching direction, nx = 1.68, ny = 1.63, (nx− ny) = 0.05, a film thickness of 70 μm, and a retardation = 3500 nm. A light-transmitting substrate was obtained in which a primer layer having a refractive index (np) of 1.56 and a film thickness of 100 nm was provided.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. The optical functional layer was formed on the primer layer. Using the obtained optical laminate, the reflectance was measured in the same manner as in Example 1 (the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 0 °), and the contrast in the bright place was evaluated. Example 4 The reflectivity of the optical laminate was 4.38%, and the S-polarized light and the slow axis of the light-transmitting substrate were parallel (the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 90). The reflectance of the optical laminated body of Comparative Example 4 measured by installing at 4 ° was 4.47%, and the optical laminated body of Example 4 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 4 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 4. It was. Further, the liquid crystal monitor A using the optical layered body of Example 4 was in a state in which the visibility improvement was extremely improved without any azimuth irregularity. On the other hand, the liquid crystal monitor B using the optical laminated body of Comparative Example 4 was inferior in bright place contrast as compared with the liquid crystal monitor A using the optical laminated body of Example 4 although no azimuth was observed. .

(Example 5, Comparative Example 5)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. A primer layer resin composition comprising 28.0 parts by mass of an aqueous dispersion and 72.0 parts by mass of water was uniformly applied by a roll coater. Next, this coated film was dried at 95 ° C., and stretched at a stretch ratio of 1.5 times in the direction of 90 degrees with respect to the previous stretching direction, nx = 1.70, ny = 1.60, (nx− ny) = 0.10, a film thickness of 38 μm, and a retardation = 3800 nm. A light-transmitting substrate having a refractive index (np) of 1.56 and a primer layer of 100 nm in thickness was obtained.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. The optical functional layer was formed on the primer layer. Using the obtained optical layered body, the reflectance of the optical layered body of Example 5 measured by installing it so that the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 30 ° was 4 The reflectance of the optical laminated body of Comparative Example 5 measured by setting the angle between the S-polarized light and the slow axis of the light-transmitting substrate to be 30 ° was 4.45%. Thus, the optical laminate of Example 5 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 5 evaluated in the same manner as in Example 1 has a brighter contrast on the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 5. It was. In addition, in the liquid crystal monitor A using the optical laminate of Example 5, Nizimura was in a level where there was no problem in practical use, and it was in a state where visibility was improved so that it could be seen slightly through polarized sunglasses. It was. On the other hand, the liquid crystal monitor B using the optical laminate of Comparative Example 5 had a level where Nizimura was slightly visible through polarized sunglasses and had no problem in practical use. Compared with the liquid crystal monitor A using A, it was inferior to the photopic contrast.
In addition, the S-polarized light in the optical laminate of Example 5 and the S-polarized light in the optical laminate of Comparative Example 5 were the liquid crystal monitor A ′ in which the angle formed by the S-polarized light and the fast axis of the light-transmitting substrate was the same angle on the minus side. When the reflectance and the bright place contrast were evaluated for the liquid crystal monitor B ′ in which the angle formed by the slow axis of the light-transmitting substrate was the same angle on the negative side, the liquid crystal monitor using the optical laminate of Example 5 was evaluated. The results were the same as those of the liquid crystal monitor B using the optical laminate of A and Comparative Example 5.

(Example 6, Comparative Example 6)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus, and then stretched at 120 ° C. to a stretch ratio of 4.5 times, and then a polyester resin aqueous dispersion 28.0 on one side. A resin composition for a primer layer composed of parts by mass and 72.0 parts by mass of water was uniformly applied using a roll coater. Next, this coated film was dried at 95 ° C., and stretched at a stretch ratio of 1.5 times in the direction of 90 degrees with respect to the previous stretching direction, nx = 1.70, ny = 1.60, (nx− ny) = 0.10, a film thickness of 10 μm, and a retardation = 1000 nm on a film having a refractive index (np) of 1.56 and a primer layer of a film thickness of 100 nm was obtained.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. Using the obtained optical layered body, set so that the S-polarized light and the phase advance axis of the light transmissive substrate are parallel (the angle between the S polarization and the phase advance axis of the light transmissive substrate is 0 °). The optical laminate of Example 6 measured in this way has a reflectance of 4.40%, and the S-polarized light and the slow axis are parallel (the angle between the S-polarized light and the fast axis of the light-transmitting substrate is 90 °). The reflectance of the optical laminated body of Comparative Example 6 measured by installing it as described above was 4.47%, and the optical laminated body of Example 6 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 6 evaluated in the same manner as in Example 1 has a brighter contrast on the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 6. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 6 was in the state where there was no azimuth and visibility was improved. On the other hand, the liquid crystal monitor B using the optical laminate of Comparative Example 6 was inferior in bright place contrast as compared with the liquid crystal monitor A using the optical laminate of Example 6 although no Nizimura was observed. .

(Example 7, Comparative Example 7)
Reflection of the optical laminate of Example 7 measured using the optical laminate obtained in Example 1 so that the angle formed between the S-polarized light and the fast axis of the light-transmitting substrate is 5 °. The reflectance is 4.46%, and the reflectance of the optical laminate of Comparative Example 7 measured so that the angle between the S-polarized light and the slow axis of the light-transmitting substrate is 5 ° is 4 °. The optical layered body of Example 7 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 7 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 7. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 7 was in a state in which there was no azimuth irregularity and the visibility improvement was extremely improved. On the other hand, the liquid crystal monitor B using the optical layered body of Comparative Example 7 does not show Nizimura, but is inferior in bright place contrast to the liquid crystal monitor A using the optical layered body of Example 7, and has antireflection performance. Was inferior.
The liquid crystal monitor A ′ in which the angle formed by the S-polarized light in the optical laminate of Example 7 and the fast axis of the light-transmitting substrate is the same angle on the negative side, and the S-polarized light in the optical laminate of Comparative Example 7 When the reflectance and the bright place contrast were evaluated for the liquid crystal monitor B ′ in which the angle formed by the slow axis of the light-transmitting substrate was the same angle on the negative side, the liquid crystal monitor using the optical laminate of Example 7 was evaluated. The results were the same as those of the liquid crystal monitor B using the optical laminate of A and Comparative Example 7.

(Example 8, comparative example 8)
Reflection of the optical laminate of Example 8 measured using the optical laminate obtained in Example 1 so that the angle between the S-polarized light and the fast axis of the light-transmitting substrate is 10 °. The reflectance is 4.48%, and the reflectance of the optical laminate of Comparative Example 8 measured so that the angle formed between the S-polarized light and the slow axis of the light-transmitting substrate is 10 ° is 4 The optical laminate of Example 8 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 8 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 8. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 8 was in a state in which there was no azimuth and the visibility was extremely improved. On the other hand, the liquid crystal monitor B using the optical laminated body of Comparative Example 8 does not show Nizimura, but is inferior to the bright place contrast and antireflection performance compared with the liquid crystal monitor A using the optical laminated body of Example 8. Was inferior.
Note that the liquid crystal monitor A ′ in which the angle formed by the S-polarized light in the optical laminate of Example 8 and the fast axis of the light-transmitting substrate is the same angle on the negative side, and the S-polarized light in the optical laminate of Comparative Example 8 The liquid crystal monitor using the optical laminate of Example 8 was evaluated with respect to the liquid crystal monitor B ′ in which the angle formed by the slow axis of the light-transmitting substrate was the same angle on the negative side. The results were the same as those of the liquid crystal monitor B using the optical laminate of A and Comparative Example 8.

(Example 9, Comparative Example 9)
Reflection of the optical laminate of Example 9 measured using the optical laminate obtained in Example 1 so that the angle between the S-polarized light and the fast axis of the light-transmitting substrate is 30 °. The reflectance is 4.56%, and the reflectance of the optical laminate of Comparative Example 9 measured so that the angle formed between the S-polarized light and the slow axis of the light-transmitting substrate is 30 ° is 4 The optical layered body of Example 9 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 9 evaluated in the same manner as in Example 1 has a brighter contrast on the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 9. It was. Further, the liquid crystal monitor A using the optical laminated body of Example 9 was free from azimuth and was in a state where the visibility was extremely improved. On the other hand, the liquid crystal monitor B using the optical laminate of Comparative Example 9 does not show nitriles, but is inferior in bright place contrast to the liquid crystal monitor A using the optical laminate of Example 9, and has antireflection performance. Was inferior.
The liquid crystal monitor A ′ in which the angle formed by the S-polarized light in the optical laminate of Example 9 and the fast axis of the light-transmitting substrate is the same angle on the negative side, and the S-polarized light in the optical laminate of Comparative Example 9 When the reflectance and the bright place contrast were evaluated with respect to the liquid crystal monitor B ′ in which the angle formed by the slow axis of the light-transmitting substrate was the same angle on the negative side, the liquid crystal monitor using the optical laminate of Example 9 was evaluated. The results were similar to those of the liquid crystal monitor B using the optical laminate of A and Comparative Example 9.

(Example 10, Comparative Example 10)
The polyethylene naphthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, and brought into close contact with a water-cooled cooled quenching drum to cool, thereby producing an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. A primer layer resin composition comprising 28.0 parts by mass of an aqueous dispersion and 72.0 parts by mass of water was uniformly applied by a roll coater. Next, the coated film was dried at 95 ° C., and stretched at a stretching ratio of 1.5 times in the direction of 90 degrees from the previous stretching direction, nx = 1.81, ny = 1.60, (nx− ny) = 0.21, a film thickness of 40 μm, and a retardation = 8400 nm. A light-transmitting substrate was obtained in which a primer layer having a refractive index (np) of 1.56 and a film thickness of 100 nm was provided.
An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. The optical functional layer was formed on the primer layer. Using the obtained optical layered body, the reflectance of the optical layered body of Example 10 measured so that the angle between the S-polarized light and the fast axis of the light-transmitting substrate was 0 ° was measured. The reflectance of the optical laminate of Comparative Example 10 measured so that the angle formed between the S-polarized light and the slow axis of the light-transmitting substrate was 0 ° was 4.79%. Thus, the optical laminate of Example 10 was superior in antireflection performance.
In addition, the liquid crystal monitor A using the optical laminate of Example 10 evaluated in the same manner as in Example 1 is particularly superior in the bright place contrast of the display screen than the liquid crystal monitor B using the optical laminate of Comparative Example 10. It was. Moreover, the liquid crystal monitor A using the optical laminated body of Example 10 was in the state where there was no azimuth and the visibility improvement was extremely improved. On the other hand, the display screen of the liquid crystal monitor B using the optical laminated body of Comparative Example 10 does not show Nizimura, but is inferior in bright place contrast as compared with the liquid crystal monitor A using the optical laminated body of Example 10. Met.

(Comparative Example 11)
The reflectance measured by using the optical layered body produced in Example 1 and setting the angle between the S-polarized light and the fast axis of the light-transmitting substrate to be 45 ° is 4.59%, S The reflectance measured by setting the polarized light and the slow axis of the light-transmitting base material to be 45 ° is also 4.59%, and there is no difference in the reflectance. It was not obtained.
A liquid crystal monitor A provided with the optical laminate of Example 9 was used, and a liquid crystal provided with an optical laminate in which the angle between the S-polarized light of Comparative Example 11 and the fast axis of the light-transmitting substrate was 45 °. Using the liquid crystal monitor B as the monitor, the bright place contrast was evaluated in the same manner as in Example 1. As a result, the bright contrast of the display screen of the liquid crystal monitor A using the optical laminate of Example 9 was superior to the bright contrast of the display screen of the liquid crystal monitor B using the optical laminate of Comparative Example 11. . In the same manner, the contrast of the liquid crystal monitor B ′ having the optical laminate in which the angle between the S-polarized light of the comparative example 11 and the slow axis of the light-transmitting substrate is 45 ° is also evaluated for the liquid crystal monitor B ′. As a result, the result was the same as that of the liquid crystal monitor B.
Next, the liquid crystal monitor using the optical laminates of Examples 1, 7 and 8 was designated as liquid crystal monitor A, and the liquid crystal monitor using the optical laminate of Example 9 was designated as liquid crystal monitor B. Similarly, the bright place contrast was evaluated. However, rather than the bright contrast of the display screen of the liquid crystal monitor B using the optical laminate of Example 9, the display screen of the liquid crystal monitor A using the optical laminates of Example 1, Example 7 and Example 8 is better. The photopic contrast was excellent.

(Comparative Example 12)
The reflectance measured by using the optical layered body manufactured in Example 3 and setting the angle between the S-polarized light and the fast axis of the light-transmitting substrate to be 45 ° is 4.42%, S The reflectance measured by setting the angle between the polarized light and the slow axis of the light-transmitting substrate to be 45 ° is also 4.42%, and there is no difference in the reflectance. It was not obtained. A liquid crystal monitor provided with an optical laminate in which the angle formed between the S-polarized light and the fast axis of the light-transmitting substrate is 45 ° is liquid crystal monitor A, and the slow axis of the S-polarized light and the light-transmitting substrate is Assuming that the liquid crystal monitor with the optical layered body formed so that the angle formed between the liquid crystal and the optical laminate is 45 ° is the liquid crystal monitor B, the Nijimura and the bright place contrast were evaluated in the same manner as in Example 1. There was no difference in the bright spot contrast at each angle, but the optical laminate of Comparative Example 12 was compared with the liquid crystal monitor A using the optical laminate of the optical laminate according to Example 3. The liquid crystal monitor using the body was inferior in bright place contrast when installed at any angle.

(Reference Example 1)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus, and then stretched at 120 ° C. to a stretch ratio of 4.5 times, and then a polyester resin aqueous dispersion 28.0 on one side. A resin composition for a primer layer consisting of parts by mass and 72.0 parts by mass of water was uniformly applied with a roll coater. Next, this coated film was dried at 95 ° C., and stretched at a stretch ratio of 1.5 times in the direction of 90 degrees with respect to the previous stretching direction, nx = 1.70, ny = 1.60, (nx− ny) = 0.10, film thickness 28 μm, retardation = 2800 nm on a film having a refractive index (np) 1.56 and a primer layer having a film thickness of 100 nm was obtained. An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. Using the obtained optical laminate, the reflectance measured by setting the angle between the S-polarized light and the fast axis of the light-transmitting substrate to be 30 ° was 4.39%, and the S-polarized light and the slow retardation were measured. The reflectivity measured by setting the phase axis to be 30 ° was 4.45%, there was a difference in reflectivity, and an antireflection effect was obtained. Also in the bright contrast, the liquid crystal monitor provided with the optical laminate installed so that the angle between the S-polarized light and the fast axis of the light-transmitting substrate is 30 ° is referred to as a liquid crystal monitor A, and the S-polarized light and the slow phase The liquid crystal monitor installed so that the angle formed with the axis was 30 ° was used as the liquid crystal monitor B, and the Nijimura and the bright place contrast were evaluated in the same manner as in Example 1. As a result, the liquid crystal monitor A was superior in the bright place contrast. However, since the retardation was less than 3000 nm, Nizimura through the polarized sunglasses was strongly observed.
In addition, a liquid crystal monitor in which the angle formed by the S-polarized light and the fast axis of the light-transmitting substrate in the optical laminate of the liquid crystal monitor A of Reference Example 1 is the same angle on the minus side is referred to as a liquid crystal monitor A ′. 1 is a liquid crystal monitor B ′ in which the angle formed between the S-polarized light and the slow axis of the light-transmitting substrate in the optical laminate of the liquid crystal monitor B is the same angle on the negative side. When the reflectivity and the bright place contrast were evaluated for the monitor B ′, the results were the same as those of the liquid crystal monitor A and the liquid crystal monitor B of Reference Example 1.

(Reference Example 2)
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute using a biaxial stretching test apparatus, then stretched at 120 ° C. to a stretching ratio of 3.8 times, and then a polyester resin aqueous dispersion 28.0 on one side. A resin composition for a primer layer comprising 7 parts by mass of water and 72.0 parts by mass of water was uniformly applied using a roll coater. Next, this coated film was dried at 95 ° C., and stretched at a stretching ratio of 1.8 times in the direction of 90 degrees from the previous stretching direction, nx = 1.66, ny = 1.63, (nx− ny) = 0.03, a film thickness of 100 μm, and a retardation = 3500 nm. A light-transmitting substrate was obtained in which a primer layer having a refractive index (np) of 1.56 and a film thickness of 100 nm was provided. An optical laminate having an optical functional layer with a refractive index (nf) of 1.53 was obtained in the same manner as in Example 1 except that the obtained light-transmitting substrate was used. Using the obtained optical laminate, measurement was performed by setting the S-polarized light and the light-transmitting base material in parallel with the fast axis (the angle between the S-polarized light and the light-transmitting base material being 0 °). The reflectance was 4.41%, and the reflection was measured by setting the S-polarized light and the slow axis of the light-transmitting substrate in parallel (the angle between the S-polarized light and the light-transmitting substrate being 0 °). The rate was 4.43%, and there was a slight difference in reflectivity, and there was an antireflection effect. Further, a liquid crystal monitor provided with an optical laminated body installed so that an angle formed between the S-polarized light and the fast axis of the light-transmitting substrate is 0 ° is referred to as a liquid crystal monitor A, and the S-polarized light and the slow axis are formed. The liquid crystal monitor installed at an angle of 0 ° was used as the liquid crystal monitor B, and when Nizimura and bright place contrast were evaluated in the same manner as in Example 1, no Nizimura was found when installed at any angle. In the photopic contrast, no difference was observed when installed at any angle, and (nx−ny) = 0.03, so the photopic contrast used the optical laminates of Examples 4 and 5. Compared to the LCD monitor.

(Reference Example 3)
nx = 1.48026, ny = 1.48019, (nx−ny) = 0.00007, a film thickness of 80 μm, an in-plane retardation of 5.6 nm, and a triacetylcellulose (TD80ULM manufactured by Fuji Film) substrate An optical laminate was prepared by providing an optical functional layer having a refractive index (nf) of 1.53 on the top in the same manner as in Example 1.
Using the obtained optical laminate, measurement was performed by setting the S-polarized light and the light-transmitting base material in parallel with the fast axis (the angle between the S-polarized light and the light-transmitting base material being 0 °). The reflectivity was 4.39%, and the reflection was measured by setting the S-polarized light and the slow axis of the light-transmitting substrate in parallel (the angle between the S-polarized light and the light-transmitting substrate being 0 °). The rate was similarly 4.39%, and there was no difference in reflectance. Although there is no difference in the reflectance, there is no problem in the reflectance because triacetyl cellulose is used as the light-transmitting substrate. The liquid crystal monitor on which the optical laminated body installed so that the angle between the S-polarized light and the phase advance axis of the light-transmitting substrate is 0 ° is set as a liquid crystal monitor A, and the retardation of the S-polarized light and the light-transmitting substrate is delayed. When the liquid crystal monitor on which the optical layered body that was installed and measured so that the angle formed with the axis was 0 ° was used as the liquid crystal monitor B, Nizimura and bright place contrast were evaluated in the same manner as in Example 1. When installed at an angle, there was no difference in photopic contrast, and there was no Nijimura. According to the reference example 3, when a light-transmitting substrate that does not have a birefringence index in a plane that has been used in a conventional liquid crystal display device is used, there is no problem of contrast in the bright place and the problem of visibility. It was confirmed that there was no. In each example, the same visibility as that of the reference example 3 was obtained.

(Production of light-transmitting substrate)
(Production of light-transmitting base material (2) A having no in-plane birefringence)
Cellulose acetate propionate (CAP504-0.2 manufactured by Eastman Chemical Co., Ltd.) was dissolved in methylene chloride as a solvent so that the solid content concentration was 15%, then cast on glass, dried, and light transmissive. Substrate (2) A was obtained. Δn at a wavelength of 550 nm was 0.00002, and the average refractive index N was 1.4838.

(Production of light-transmitting substrate (2) a having in-plane birefringence)
The light transmissive substrate (2) A was uniaxially stretched 1.5 times at 160 ° C. to produce a light transmissive substrate (2) a having in-plane birefringence. As a result of calculating the three-dimensional refractive index wavelength dispersion, the refractive index nx = 1.4845 at a wavelength of 550 nm, ny = 1.4835 (Δn = 0.001), and nz = 1.4834.

(Preparation of light transmissive substrate (2) B having no in-plane birefringence)
As the light transmissive substrate (2) B, an unstretched ZEONOR made by Nippon Zeon Co., Ltd., made of a cycloolefin polymer was prepared. Δn = 0.00004 at a wavelength of 550 nm, and the average refractive index N = 1.5177.

(Production of light-transmitting substrate (2) b having in-plane birefringence)
The light transmissive substrate (2) B was uniaxially stretched 1.5 times at 150 ° C. to produce a light transmissive substrate (2) b having birefringence in the plane. As a result of calculating the three-dimensional refractive index wavelength dispersion, the refractive index at a wavelength of 550 nm was nx = 1.5186, ny = 1.5172, and nz = 1.5173.

(Production of light-transmitting base material (2) C having no in-plane birefringence)
The polyethylene terephthalate material was melted at 290 ° C. and slowly cooled on glass to obtain a light-transmitting substrate (2) C. Δn = 0.00035 at a wavelength of 550 nm, and the average refractive index N1.6167.

(Production of light-transmitting substrate (2) c1 having birefringence in the plane)
The light transmissive substrate (2) C was uniaxially stretched 4.0 times at 120 ° C. to produce a light transmissive substrate (2) c1 having birefringence in the plane. The refractive index wavelength dispersion (nx, ny) was calculated using a spectrophotometer. The refractive index at a wavelength of 550 nm was nx = 1.701, ny = 1.0165, and nz = 1.5476.

(Production of light-transmitting substrate (2) c2 having in-plane birefringence)
The light transmissive substrate (2) C was uniaxially stretched 2.0 times at 120 ° C. to produce a light transmissive substrate (2) c2 having birefringence in the plane. The refractive index wavelength dispersion (nx, ny) was calculated using a spectrophotometer. The refractive index at a wavelength of 550 nm was nx = 1.511, ny = 1.5998, and nz = 1.5992.

(Preparation of light transmissive substrate (2) c3 having in-plane birefringence)
The light-transmitting substrate (2) C3 was adjusted at 120 ° C. to adjust the biaxial stretching ratio to produce a light-transmitting substrate (2) c3 having in-plane birefringence. The refractive index wavelength dispersion (nx, ny) was calculated using a spectrophotometer. The refractive index at a wavelength of 550 nm was nx = 1.6652, ny = 1.6153, and nz = 1.5696.

(Production of light-transmitting substrate (2) c4 having in-plane birefringence)
The light transmissive substrate (2) C was adjusted to a biaxial stretching ratio at 120 ° C. to produce a light transmissive substrate (2) c4 having in-plane birefringence. The refractive index wavelength dispersion (nx, ny) was calculated using a spectrophotometer. The refractive index at a wavelength of 550 nm was nx = 1.6708, ny = 1.6189, and nz = 1.5604.

(Preparation of light transmissive substrate (2) D having no in-plane birefringence)
The polyethylene naphthalate material was melted at 290 ° C. and slowly cooled on glass to obtain a light-transmitting substrate (2) D. At the wavelength of 550 nm, Δn = 0.004, and the average refractive index N = 1.6833.

(Production of light-transmitting substrate (2) d having birefringence in the plane)
The light transmissive substrate (2) D was uniaxially stretched 4.0 times at 120 ° C. to produce a light transmissive substrate (2) d having birefringence in the plane. The refractive index wavelength dispersion (nx, ny) was calculated using a spectrophotometer. The refractive index at a wavelength of 550 nm was nx = 1.8472, ny = 1.6466, and nz = 1.5561.

(Calculation of polarizing plate transmittance)
The transmittance can be calculated using a 2 × 2 matrix method, a 4 × 4 matrix method, or an extended Jones matrix method. In the examples, comparative examples, and reference examples, the transmittance of the polarizing plate was calculated using simulation software (LCD Master, manufactured by Shintec Co., Ltd.). FIG. 5 shows the layer structure of the polarizing plate. The above calculation was performed by putting the three-dimensional refractive index wavelength dispersion of each light-transmitting substrate (2) into the Example and Comparative Example portions of FIG. The light-transmitting substrate (2) determined to have no birefringence in the plane has an average refractive index N = nx = ny = nz, and the light-transmitting substrate determined to have birefringence in the surface ( For 2), measured values were used. The film thickness of each layer was set to 80 μm in the examples, comparative examples, and the protective film part, and 20 μm in the polarizer (2) part.
The spectrum of the light source is as shown in FIG. The polarization state of the incident light was linearly polarized so as to be the same as the polarization state after passing through the polarization separation film, and the light oscillated in the transmission axis direction of the polarizer (2).
FIG. 6 shows the refractive index wavelength dispersion of the protective film used, and the protective film was an isotropic material.
FIG. 7 shows the refractive index and extinction coefficient of the polarizer (2) used. In FIG. 7, the absorption axis direction and the transmission axis direction are substantially overlapped.

(Example 11)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate (2) a, the angle between the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is 0 °. The transmittance of the polarizing plate was calculated.

(Example 12)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate (2) a, the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is 90 °. The transmittance of the polarizing plate was calculated.

(Comparative Example 13)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate (2) a, the angle formed by the fast axis of the light transmissive substrate (2) and the transmission axis of the polarizer (2) is 45 °. The transmittance of the polarizing plate was calculated.

(Example 13)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate (2) b, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 0 °, The transmittance of the polarizing plate was calculated.

(Example 14)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate b, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 90 °, Transmittance was calculated.

(Comparative Example 14)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate b, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 45 °, Transmittance was calculated.

(Example 15)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 0 °, Transmittance was calculated.

(Example 16)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 2 °, Transmittance was calculated.

(Example 17)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 30 °, Transmittance was calculated.

(Example 18)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 60 °. Transmittance was calculated.

(Example 19)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 90 °. Transmittance was calculated.

(Comparative Example 15)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c1, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 45 °. Transmittance was calculated.

(Example 20)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c2, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 0 °. Transmittance was calculated.

(Example 21)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c2, the angle between the phase advance axis of the light transmissive substrate and the transmission axis of the polarizer is 90 °, Transmittance was calculated.

(Comparative Example 16)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate c2, the angle between the fast axis of the light-transmitting substrate and the transmission axis of the polarizer is set to 45 °. Transmittance was calculated.

(Example 22)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c3, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 0 °. Transmittance was calculated.

(Example 23)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c3, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 90 °, Transmittance was calculated.

(Comparative Example 17)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c3, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 45 °. Transmittance was calculated.

(Example 24)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c4, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is set to 0 °. Transmittance was calculated.

(Example 25)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate c4, the angle between the phase advance axis of the light transmissive substrate and the transmission axis of the polarizer is 90 °, Transmittance was calculated.

(Comparative Example 18)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate c4, the angle between the fast axis of the light-transmitting substrate and the transmission axis of the polarizer is set to 45 °. Transmittance was calculated.

(Example 26)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate d, the angle between the fast axis of the light-transmitting substrate and the transmission axis of the polarizer is set to 0 °. Transmittance was calculated.

(Example 27)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate d, the angle between the fast axis of the light transmissive substrate and the transmission axis of the polarizer is 90 °, Transmittance was calculated.

(Comparative Example 19)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate d, it is installed so that the angle between the fast axis of the light-transmitting substrate and the transmission axis of the polarizer is 45 °. Transmittance was calculated.

(Reference Example 4)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate A, the transmittance of the polarizing plate was calculated.

(Reference Example 5)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate B, the transmittance of the polarizing plate was calculated.

(Reference Example 6)
Using the three-dimensional refractive index wavelength dispersion of the light-transmitting substrate C, the transmittance of the polarizing plate was calculated.

(Reference Example 7)
Using the three-dimensional refractive index wavelength dispersion of the light transmissive substrate D, the transmittance of the polarizing plate was calculated.

(Reference Example 8)
The transmittance of the polarizing plate was calculated in the same manner as in Example 5 except that the polarization state of incident light was random light.

(Reference Example 9)
The transmittance of the polarizing plate was calculated in the same manner as in Example 9 except that the polarization state of incident light was random light.

(Reference Example 10)
The transmittance of the polarizing plate was calculated in the same manner as in Comparative Example 3 except that the polarization state of incident light was random light.

(Reference Example 11)
The transmittance of the polarizing plate was calculated in the same manner as in Reference Example 3 except that the polarization state of incident light was random light.

Table 1 shows each evaluation result according to Examples 11 to 27, Comparative Examples 13 to 19 and Reference Examples 4 to 11.
The transmittance when the polarization state of incident light is linearly polarized light is the transmittance of a polarizing plate having in-plane birefringence, where 100 is the transmittance when there is no in-plane birefringence for each material. Shows the rate. Similarly, the transmittance when the polarization state of incident light is random light is also shown as the transmittance of a polarizing plate having in-plane birefringence, where 100 is the transmittance when there is no in-plane birefringence. ing.

As shown in Table 1, the comparison between Examples 11 and 12 and Comparative Example 13, the comparison between Examples 13 and 14 and Comparative Example 14, the comparison between Examples 15 to 19 and Comparative Example 15, and the Example 20 , 21 and Comparative Example 16, Comparative Examples 22 and 23 and Comparative Example 17, Comparative Examples 24 and 25 and Comparative Example 18, and Comparative Examples 26 and 27 and Comparative Example 19 Accordingly, the polarizing plate according to the example in which the slow axis of the light-transmitting substrate (2) and the transmission axis of the polarizer (2) are within a predetermined angular range is the polarization according to the comparative example that is out of the angular range. It was more light transmissive than the plate.
Further, comparison between Example 11 and Reference Example 4, comparison between Example 13 and Reference Example 5, comparison between Examples 15, 20, and 22 and Reference Example 6, comparison between Example 26 and Reference Example 7 The polarizing plate according to the example using the light-transmitting base material (2) having the birefringence in the plane is a comparison using the light-transmitting base material (2) having no birefringence in the plane. It was superior in light transmittance than the polarizing plate according to the example.
From the comparison between Examples 15 and 19, Comparative Example 15, Reference Example 6, and Reference Examples 8 to 11, when the polarized light is incident, the slow axis of the light-transmitting substrate (2) and the polarizer It was confirmed that the polarizing plate according to the example in which the transmission axis of (2) is within a predetermined angle range is superior in light transmittance to the polarizing plate according to the comparative example that is out of the angle range.

Furthermore, when the polarizing plate composite was manufactured by appropriately combining the optical laminates according to Examples 1 to 10 and the polarizing plates according to Examples 11 to 27, the obtained polarizing plate composite had antireflection performance. It was confirmed that it was excellent in light place contrast, could prevent Nizimura, and had excellent light transmittance.

The polarizing plate composite of the present invention includes a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), a touch panel, electronic paper, and a tablet PC. It can apply suitably to.

Claims (1)

An optical layered body having an optical functional layer on one surface of a light-transmitting substrate (1) having a birefringence in-plane, and being used on the surface of an image display device;
From the backlight light source side, at least a light-transmitting base material (2) having a birefringence in the plane and a polarizer (2) are laminated in this order, and arranged on the backlight light source side of the image display device. A polarizing plate composite having a polarizing plate to be used,
The slow axis, which is the direction in which the refractive index of the light transmissive substrate (1) is large, is arranged in parallel with the vertical direction of the display screen of the image display device,
Polarized light is incident on the light transmissive substrate (2),
The light transmissive substrate (2) and the polarizer (2) are a fast axis that is a direction in which the refractive index of the light transmissive substrate (2) is small, and a transmission axis of the polarizer (2). The polarizing plate composite is characterized in that it is laminated so that the angle formed between and 0 ° ± 30 ° or 90 ° ± 30 °.

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