TWI580994B - A laminated substrate, a laminate, a laminate plate, a liquid crystal display panel, and an image display device - Google Patents

Description

Laminated substrate, laminate, polarizing plate, liquid crystal display panel and image display device

The present invention relates to a laminated substrate, a laminate, a polarizing plate, a liquid crystal display panel, and an image display device.

The image display surface in an image display device such as a liquid crystal display device, a cathode ray tube display device (CRT), a plasma display (PDP), an electroluminescence display (ELD), or a field emission display (FED) is usually directly Or, between other components (such as a touch panel sensor), a laminate having a functional layer that is expected to perform the desired function is provided. Typical functional layers include, for example, a hard coat layer for the purpose of improving scratch resistance.

Further, as the light-transmitting substrate supporting the laminate of the functional layers, a film having an optical isotropic property without birefringence, and typically a film composed of cellulose ester represented by triethylenesulfonyl cellulose can be used. . When a film having birefringence is used, for example, when a display surface of a display device using a polarized light is used in a liquid crystal display device, defects such as colored spots (hereinafter also referred to as "rainbow spots") having different colors are generated. But cellulose ester film has moisture resistance The heat is inferior, and when used in a high-temperature and high-humidity environment, the polarizing function or the function of the polarizing plate having the same color is lowered.

Because of the problem of such a cellulose ester film, it has been desired to use various types of general-purpose films which are easily obtained in the market or can be easily produced as a light-transmitting substrate of a laminate. For example, JP2011-107198A uses a white light-emitting diode as a light source, and has a retardation of a polymer film of 3000 nm to 30000 nm, and the angle formed by the absorption axis of the polarizing plate and the slow axis of the polymer film is 45 degrees. When the screen is viewed through a polarizing plate such as sunglasses, it is possible to ensure good visibility without observing the angle.

However, when a hard coat layer is formed on a polyester or polycarbonate film of a preferred polymer film in JP 2011-107198 A, the occurrence of rainbow spots can be suppressed, but another problem is that the interference fringes are not visible. Wherein, interference fringes refer to interference caused by light that is reflected on the surface of the functional layer and light that is reflected at the interface between the functional layer and the light transmissive substrate upon incident on the functional layer, and a part of the iridescent color is visible. The phenomenon of color, the phenomenon caused by the viewing direction becoming a strengthened wavelength. This phenomenon is not only difficult for the user to see and has an uncomfortable impression, but is strongly required to be improved.

The interference fringe measures, for example, reduces the difference in refractive index between the functional layer and the light-transmitting substrate, and reduces the reflectance at the interface between the functional layer and the light-transmitting substrate. However, the light-transmitting substrate has in-plane birefringence. When the retardation value is high, it is necessary to increase the thickness of the light-transmitting substrate when the thickness of the light-transmitting substrate is increased from the viewpoint of the cost surface or the like. Refractive index in the direction of the slow axis The refractive index difference of the refractive index in the fast axis direction. Therefore, it is difficult to reduce the difference in refractive index between the functional layer and the light-transmitting substrate in both the slow axis direction and the fast axis direction, and as a result, the interference fringes are not sufficiently made inconspicuous.

[Invention]

The present invention has been made in view of the above problems, and it is intended to use a light-transmitting substrate having in-plane birefringence to make interference fringes inconspicuous.

The laminated substrate of the present invention is a laminated substrate in which a functional layer is formed on one surface and is a laminate, and the light-transmitting substrate having in-plane birefringence is provided.

a refractive index adjusting layer which is laminated on the light-transmitting substrate and has an in-plane birefringence and which is located between the light-transmitting substrate and the functional layer.

The refractive index n _{1x in the} slow axis direction, which is the direction in which the refractive index of the light transmissive substrate is the largest, and the refractive index n _2x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmissive substrate, And a refractive index n _{3x of the} functional layer in a direction parallel to the slow axis direction of the light transmissive substrate satisfies a relationship of n _1x <n _2x <n _3x or n _1x >n _2x >n _3x .

a refractive index n _{1y in} the fast axis direction orthogonal to the slow axis direction of the light transmissive substrate, and a refractive index n _2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light transmissive substrate, And a refractive index n _{3y of the} functional layer in a direction parallel to the fast axis direction of the light transmissive substrate satisfies a relationship of n _1y <n _2y <n _3y or n _1y >n _2y >n _3y .

The laminated substrate of the present invention, wherein a refractive index n _2x of the refractive index adjusting layer in a direction parallel to the slow axis direction of the light transmissive substrate and a direction parallel to the fast axis direction of the light transmissive substrate The refractive index n _2y of the refractive index adjusting layer may satisfy the relationship of n _2x >n _2y .

The laminated substrate of the present invention, wherein the refractive index n _{1x in the} slow axis direction of the light transmissive substrate, the refractive index n _{1y in the} fast axis direction of the light transmissive substrate, and the light transmissive substrate The refractive index n _2x of the refractive index adjusting layer in the parallel direction of the slow axis direction and the refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light transmitting substrate may also satisfy (n) _{The relationship of 1x -} n _1y ) > (n _{2x -} n _2y ).

In the laminated base material of the present invention, when the laminated base material is observed in a normal direction, the slow axis direction of the light transmissive base material and the refractive index maximum direction in the refractive index adjustment layer, that is, the refractive index adjustment The angle formed by the slow axis direction of the layer may also be less than 45 degrees.

In the laminated substrate of the present invention, the slow axis direction of the light-transmitting substrate may be parallel to a direction of a maximum refractive index in the refractive index adjusting layer, that is, a slow axis direction of the refractive index adjusting layer.

In the laminated substrate of the present invention, the refractive index n _{1x in the} slow axis direction of the light transmissive substrate, the refractive index n _{1y in the} fast axis direction of the light transmissive substrate, and the refractive index adjustment layer The refractive index maximum direction, that is, the refractive index n _{2a in} the slow axis direction of the refractive index adjusting layer, and the refractive index n _{2b in} the fast axis direction of the refractive index adjusting layer orthogonal to the slow axis direction of the refractive index adjusting layer are also The relationship of (n _{1x -} n _1y ) > (n _{2a -} n _2b ) can be satisfied.

In the laminated substrate of the present invention, the refractive index n _{1x in the} slow axis direction of the light transmissive substrate and the refractive index adjustment layer in the direction parallel to the slow axis direction dx of the light transmissive substrate are The refractive index n _{3x of the} functional layer having a rate n _2x and a direction parallel to the slow axis direction of the light transmissive substrate may satisfy n ₂ = (n _2x + n _2y )/2 and |n _2x - ( a relationship between (n _1x + n _3x ) / 2) | < | n ₂ - (( n _1x + n _3x ) / 2)|, the refractive index n _{1y in the} fast axis direction of the light transmissive substrate, and the foregoing The refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light transmissive substrate and the refractive index n _{3y of the} functional layer in a direction parallel to the fast axis direction of the light transmissive substrate satisfy n ₂ = (n _2x + n _2y ) / 2, and | n _2y - (( n _1y + n _3y ) / 2) | < | n ₂ - ((n _1y + n _3y ) / 2) |

The laminated substrate of the present invention, wherein the laminated substrate may have a retardation of 3000 nm or more.

In the laminated substrate of the present invention, the light-transmitting substrate may have a retardation of 3000 nm or more.

A laminate according to the present invention, comprising any one of the laminated substrates of the present invention described above and a functional layer formed on one surface of the laminated substrate.

The refractive index adjusting layer is located on the light transmissive substrate and the aforementioned function Between the layers.

The laminate of the present invention, wherein the aforementioned functional layer may be a hard coat layer.

The laminate of the present invention may further comprise a second functional layer provided on a side opposite to the laminated substrate of the functional layer. In the laminate of the present invention, the second functional layer may be a low refractive index layer having a lower refractive index than the functional layer.

A polarizing plate according to the present invention comprises any one of a polarizing element and the laminated substrate of the present invention or a laminate of the present invention as described above.

A polarizing plate according to the present invention comprises any one of the above-described laminated substrates of the present invention or any of the above-described laminates of the present invention, or any of the above-described polarizing plates of the present invention.

A liquid crystal display panel according to the present invention comprises any one of the above-described laminated substrates of the present invention or any of the above-described laminates of the present invention, or any of the above-described polarizing plates of the present invention.

The touch panel device of the present invention includes any one of the above-described laminated substrate of the present invention provided on the touch panel sensor, or the laminate of the present invention, or the above Any of the polarizing plates of the invention.

According to the invention, a refractive index adjusting layer having in-plane birefringence is provided between the functional layer and the light transmissive substrate having in-plane birefringence. By this refractive index adjusting layer, the reflectance of light incident on the functional layer can be reduced. Thereby, the interference fringes can be made inconspicuous.

10‧‧‧Layer

11‧‧‧Laminated substrate

20‧‧‧Polar plate

12‧‧‧Light transmissive substrate

13‧‧‧Refractive index adjustment layer

15‧‧‧ functional layer

22‧‧‧Protective film

30‧‧‧LCD panel

31‧‧‧Protective film

32‧‧‧Polarized components

33‧‧‧ phase difference film

34‧‧‧Adhesive layer

35‧‧‧Liquid cell

36‧‧‧Adhesive layer

37‧‧‧ phase difference film

40‧‧‧Image display device

Fig. 1 is an explanatory view showing an embodiment of the present invention, showing a layer configuration of a laminate.

Fig. 2 is a view corresponding to Fig. 1 and showing a layer configuration diagram of another example of the functional layer.

Fig. 3 is a diagram showing the distribution of the refractive index in the laminate shown in Fig. 1, and the laminated view is a perspective view schematically shown.

Fig. 4 is a plan view showing in-plane birefringence in a laminated substrate shown in Fig. 1, and a plan view of a laminated substrate in a mode.

FIG. 5 is a schematic configuration view showing a polarizing plate including the laminate shown in FIG. 1. FIG.

Fig. 6 is a schematic block diagram showing a liquid crystal display panel including the laminate shown in Fig. 1 .

Fig. 7 is a schematic block diagram showing a display device including the laminate shown in Fig. 1;

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Moreover, the drawings attached to the present specification are easy to show and understand, and for the sake of convenience, the size of the physical object or the like is changed by an appropriate scale, a vertical-to-horizontal size ratio, or the like. 1 to 7 are views for explaining an embodiment of the present invention. 1 and 2 are views for explaining a laminated base material and a laminate. image 3 4 is a view for explaining a refractive index distribution of a laminated base material and a laminate. 5 to 7 are schematic views showing the configuration of a polarizing plate, a liquid crystal display panel, and a laminate.

≪Laminated substrate and laminate ≫ <Overall structure of laminated substrate and laminate>

First, the overall configuration of the laminated base material 11 and the laminated body 10 will be described. As shown in FIG. 1, the laminate 10 has a laminated substrate 11 and a functional layer 15 formed on one surface of the laminated substrate 11. The laminated base material 11 has a light-transmitting substrate 12 and a refractive index adjusting layer 13 laminated with the light-transmitting substrate 12 . In the laminate 10, the refractive index adjusting layer 13 is located between the light transmissive substrate 12 and the functional layer 15. In other words, the functional layer 15 is laminated on the laminated substrate 11 from the side of the refractive index adjusting layer 13 . In the illustrated example, the refractive index adjusting layer 13 is formed on one surface of the light-transmitting substrate 12 in the laminated base material 11. In other words, the laminate 10 is composed of three layers of the light-transmitting substrate 12, the refractive index adjusting layer 13, and the functional layer 15, and the refractive index adjusting layer 13 is adjacent to the light-transmitting substrate 12 and the functional layer 15. The arrangement forms an interface between the light transmissive substrate 12 and the functional layer 15, respectively.

2 is a laminate showing a modification of one of the laminates 10 shown in FIG. 1. The laminate 10 shown in Fig. 2 is different from the laminate 10 of Fig. 1 in that the second functional layer 17 is formed on the surface on the side opposite to the laminated substrate 11 of the functional layer 15. In the laminate 10 shown in FIG. 1, the functional layer 15 may be composed of a hard coat layer formed on one surface of the laminated substrate 11. Further, in the laminate 10 shown in FIG. 2, the functional layer 15 may be shaped The hard functional layer formed on one surface of the laminated substrate 11 is formed of a low refractive index layer formed on the side opposite to the laminated substrate 11 of the hard coat layer.

The light-transmitting substrate 12 contained in the laminated base material 11 is optically anisotropic and has at least in-plane birefringence. Further, the refractive index adjusting layer 13 contained in the laminated base material 11 is also optically anisotropic and has at least in-plane birefringence. Therefore, as shown in FIGS. 3 and 4, the refractive index of the light-transmitting substrate 12 in the two directions orthogonal to the sheet surface of the sheet-like light-transmitting substrate 12 is different. Similarly, the refractive index of the refractive index adjusting layer 13 in the two orthogonal directions of the sheet faces of the sheet-like refractive index adjusting layer 13 is different.

In addition, the "film surface (film surface, plate surface)" refers to a film-like (film-like, plate-shaped) member to be a target, and when viewed as a whole, in the overall direction, it is aligned with the planar direction of the target film-like member. Face. In an embodiment described in the embodiment, the film surface of the light transmissive substrate 12, the film surface of the refractive index adjusting layer 13, the film surface of the functional layer 15, the film surface of the laminated substrate 11, and the film of the laminate 10. The facial systems are parallel to each other.

Further, whether the light-transmitting substrate 12 or the refractive index adjusting layer 13 has in-plane birefringence, and determining the maximum refraction in the plane of the light-transmitting substrate 12 or the refractive index adjusting layer 13 at a refractive index of 550 nm The rate difference Δn (the maximum value of the refractive index difference along the two directions of the film surface) satisfies the condition of Δn ≧ 0.0005. In other words, when the maximum refractive index difference Δn in the plane of the light-transmitting substrate 12 is 0.0005 or more, it is determined that the light-transmitting substrate 12 has birefringence and the most in-plane of the light-transmitting substrate 12 When the large refractive index difference Δn is less than 0.0005, it is judged that the light-transmitting substrate 12 does not have birefringence. Similarly, when the maximum refractive index difference Δn in the plane of the refractive index adjusting layer 13 is 0.0005 or more, it is judged that the refractive index adjusting layer 13 has birefringence, and the maximum refractive index difference Δn in the plane of the refractive index adjusting layer 13 is not reached. At 0.0005, it is judged that the refractive index adjusting layer 13 does not have birefringence. The birefringence was measured using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd., and the measurement angle was set to 0° and the measurement wavelength was 552.1 nm. At this time, in the calculation of the birefringence, the film thickness and the average refractive index are required. The film thickness, for example, a light-transmitting film can be measured using a micrometer (Digimatic Micrometer, manufactured by Mitutoyo Co., Ltd.) or an electric micrometer (manufactured by Anritsu Co., Ltd.). Further, when the refractive index adjusting layer 13 is formed of a thin film layer, the cross section is observed by TEM, and the height of the target layer is measured at least 10 or more, and the average value is obtained as the film thickness. The average refractive index was measured using an Abbe refractometer (NAR-4T manufactured by Atago Co., Ltd.) or an "Ellipsometer" manufactured by JASCO Corporation.

TD80UL-M (made by Fuji Film Co., Ltd.) made of triacetyl cellulose, and ZF16-100 (made by Japan Zeon Co., Ltd.) made of triacetyl cellulose, which is known as an isotropic material, is generally known. Since the maximum refractive index difference Δn is 0.0000375 and 0.00005 by the above-described measurement methods, it is judged that it does not have birefringence (isotropy).

The laminate 10 described herein is a refractive index n _{1x in} the slow axis direction dx of the refractive index maximum direction in the plane of the light transmissive substrate 12, and a refractive index parallel to the slow axis direction dx of the light transmissive substrate 12 The refractive index n _{2x of the} adjustment layer and the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction dx of the light transmissive substrate 12 satisfy n _1x <n _2x <n _3x , or n _1x >n _2x >n _3x condition (a). Further, in the plane of the light-transmitting substrate 12, the refractive index n _{1y in} the fast axis direction dy orthogonal to the slow axis direction dx and the refractive index adjusting layer 13 in the direction parallel to the fast axis direction dy of the light transmitting substrate 11 The refractive index n _2y and the refractive index n _3y of the functional layer 15 in the direction parallel to the fast axis direction dy of the light transmissive substrate 12 satisfy n _1y <n _2y <n _3y or n _1y >n _2y >n _3y Condition (b).

In other words, the refractive index adjusting layer 13 is disposed between the functional layer 15 and the light transmissive substrate 12 having birefringence, and is in the slow axis direction dx and the fast axis direction dy of the light transmissive substrate 12. In the direction, the refractive index is divided into two stages. Thereby, between the functional layer 15 and the light-transmitting substrate 12 having birefringence, an interface in which the refractive index of the light-transmitting substrate 12 in the slow axis direction dx greatly changes does not exist, and the light-transmitting substrate 12 is not present. The interface in which the refractive index of the fast axis direction dy changes greatly does not exist. In other words, between the functional layer 15 and the light-transmitting substrate 12 having birefringence, the difference in refractive index between the slow axis direction dx and the fast axis direction dy of the light-transmitting substrate 12 is small, so that only reflection exists. Rate reduced interface.

Therefore, during the period in which the light incident on the laminated body 10 on the functional layer 15 side passes through the light-transmitting substrate 12, it is possible to effectively prevent the direction from being reversed by the reflection. Thereby, the light incident on the surface of the functional layer 15 from the side of the functional layer 15 can effectively make the light reflected on the surface of the functional layer 15 and the interface between the functional layer 15 and the refractive index adjusting layer 13 or the refractive index adjusting layer 13 And light The interference fringes generated by the light reflected by the interface of the permeable substrate 12 are not conspicuous.

Further, the refractive index n _2x of the refractive index adjusting layer 13 in the direction parallel to the slow axis direction dx of the light transmitting substrate 12 and the refractive index adjusting layer 13 in the direction parallel to the fast axis direction dy of the light transmitting substrate 12 The condition (c) in which the refractive index n _2y satisfies n _2x >n _2y is preferable. At this time, between the functional layer 15 and the light-transmitting substrate 12 having birefringence, the refractive index of the slow-axis direction dx of the light-transmitting substrate 12 can be divided into two small changes each time, and light transmittance is obtained. The refractive index of the fast axis direction dy of the substrate 12 can also be divided into two small changes each time. Thereby, during the period in which the light incident on the laminated body 10 on the functional layer 15 side passes through the light-transmitting substrate 12, it is possible to effectively prevent the direction from being reversed by the reflection. As a result, the interference fringes can be made more effective.

When the condition (c) is satisfied, the refractive index n _1x of the light-transmitting substrate 12 in the slow axis direction dx, the refractive index n _{1y of the} light-transmitting substrate 12 in the fast axis direction dy, and the light-transmitting substrate 12 The refractive index n _2x of the refractive index adjusting layer 13 in the parallel direction of the slow axis direction dx and the refractive index n _2y of the refractive index adjusting layer 13 in the direction parallel to the fast axis direction dy of the light transmitting substrate 12 satisfy (n _1x - The condition (d) of n _1y )>(n _2x -n _2y ) is more preferable. For example, the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction dx of the light transmissive substrate 12 and the refractive index n _3y of the functional layer 15 in the direction parallel to the fast axis direction dy of the light transmissive substrate 12 are absent. When there is a large difference, the functional layer 15 is typically optically isotropic. When the birefringence is not present, the refractive index adjusting layer 13 does not need to exhibit a strong birefringence or more because the condition (c) and the condition (d) are satisfied. The refractive index of the light transmissive substrate 12 in both the slow axis direction dx and the fast axis direction dy can be changed twice in a small amount. Therefore, the light incident on the laminated body 10 from the side of the functional layer 15 is prevented from being deflected by the reflection during the period of the light-transmitting substrate 12. As a result, the interference fringes can be made more effective.

Further, as shown in FIG. 4, when the laminated base material 11 is observed in the normal direction (the normal direction of the film surface of the laminated base material 11), the slow axis direction dx of the light transmitting substrate 12 and the refractive index adjusting layer The angle θ formed by the slow axis direction da of the refractive index adjusting layer 13 in the direction of the refractive index in the plane of the surface 13 is preferably less than 45 (condition (e)). The smaller the angle θ is, the smaller the refractive index distribution in the plane of the refractive index adjusting layer 13 is, and the smaller the distribution of the refractive index in the plane of the light-transmitting substrate 12 is. In other words, when the angle θ is less than 45°, not only the direction of the slow axis direction dx and the fast axis direction dy of the light transmissive substrate 12 but also the directions along the film faces of the light transmissive substrate 12 are refracted. The rate is not greatly changed between the functional layer 15 and the light-transmitting substrate 12, and is gradually changed into two. In particular, when the angle θ is 0°, in other words, when the slow axis direction dx of the light transmissive substrate 12 is parallel to the slow axis direction da of the refractive index adjusting layer 13 (condition (f)), the refractive indices of the respective directions are different. The change in the refractive index of the direction exhibits the same tendency, and the functional layer 15 and the light-transmitting substrate 12 are gradually divided into two. Thereby, the light incident on the laminated body 10 from the side of the functional layer 15 is very effectively prevented from being deflected by the reflection during the period of the light-transmitting substrate 12, and the interference fringes can be made very effective.

The ellipses depicted on the light transmissive substrate 12 in FIG. The circle indicates a cross section on the light-transmitting substrate 12 which is an example of a refractive index ellipsoid showing the refractive index distribution of the light-transmitting substrate 12. Similarly, the ellipse depicted on the refractive index adjusting layer 13 in FIG. 4 represents a cross section on the refractive index adjusting layer 13 which is an example of the refractive index ellipsoid showing the refractive index distribution of the refractive index adjusting layer 13.

Further, the refractive index n _1x of the slow-transmitting direction dx of the light-transmitting substrate 12, the refractive index n _1y of the fast-axis direction dy of the light-transmitting substrate 13, and the refractive index n of the slow-axis direction da of the refractive index adjusting layer 13 The refractive index n _2b of the fast axis direction db of _2a and the refractive index adjusting layer is preferably a condition (g) satisfying (n _{1x -} n _1y ) > (n _{2a -} n _2b ). When the condition (g) is satisfied, as in the case where the above condition (d) is satisfied, the refractive index adjusting layer 13 can be prevented from having a strong birefringence or more, whereby the interference fringes can be effectively made inconspicuous.

Further, one or more of the above conditions (a) to (g), and the in-plane average refractive index n ₁ (n ₁ = (n _1x + n _{1 y} ) / 2) of the light-transmitting substrate 12, and the refractive index adjusting layer 13 The in-plane average refractive index n ₂ (n ₂ = (n _2x + n _2y )/2) and the in-plane average refractive index n _{3 of the} functional layer 15 (n ₃ = (n _3x + n _3y )/2) satisfy The condition (h) of n ₁ < n ₂ < n ₃ or n ₁ > n ₂ > n ₃ is preferred. When the condition (h) is satisfied, moderate birefringence can be imparted to the refractive index adjusting layer 13, whereby the interference fringes can be effectively made inconspicuous.

Typically, the light transmissive substrate 12 is formed of a biaxially oriented polyethylene terephthalate film, and when the functional layer 15 functions as a hard coat layer, the light transmissive substrate 12 can have strong birefringence. At the same time, the in-plane average refractive index n ₁ of the light-transmitting substrate 12 is larger than the in-plane average refractive index n _{3 of the} functional layer 15. At this time, since the condition (h) is satisfied, the refractive index adjusting layer 13 can have birefringence in accordance with the degree of birefringence of the functional layer 15, and can effectively make the interference fringes inconspicuous.

Further, one or more of the above conditions (a) to (h), the refractive index n _1x of the light-transmitting substrate 12 in the slow axis direction dx, and the refractive index n _{1y of the} light-transmitting substrate 12 in the fast axis direction dy, The refractive index n _2x of the refractive index adjusting layer 13 in the direction parallel to the slow axis direction dx of the light transmitting substrate 12 and the refractive index n of the refractive index adjusting layer 13 in the direction parallel to the fast axis direction dy of the light transmitting substrate 12 _2y , the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction dx of the light transmissive substrate 12, and the refractive index n _3y of the functional layer 15 in the direction parallel to the fast axis direction dy of the light transmissive substrate 12 Satisfying |n _2x -((n _1x +n _3x ))/2)|<|((n _2x +n _2y )/2)-((n _1x +n _3x )/2)|, and |n _2y - The condition (i) of ((n _1y + n _3y ))/2)|<|((n _2x +n _2y )/2)-((n _1y +n _3y )/2)| is preferable. When the condition (i) is satisfied, the difference in refractive index between the refractive index adjusting layer 13 and the light transmissive substrate 12 and the difference in refractive index between the refractive index adjusting layer 13 and the functional layer 15 can be prevented, and as a result, light can be obtained. The difference in refractive index between the permeable substrate 12 and the functional layer 15 changes a little at a time. Thereby, the interference fringes can be effectively made inconspicuous.

An indicator indicating the degree of in-plane birefringence, such as a retardation Re, is known. The retardation Re is a refractive index n _{max in} the slow axis direction which is the maximum value, a refractive index _{nmin in} the fast axis direction which is the minimum value, and a thickness d (unit: nm), which are shown below.

Re[nm]=(n _max -n _min )×d[nm]

Also, as disclosed in JP 2011-107198 A, it is preferable that the laminated substrate 11 has a retardation of 3000 nm or more from the viewpoint of preventing rainbow spots. Further, when the condition (d) or the condition (g) is satisfied, the light-transmitting substrate 12 has a retardation of 3,000 nm or more. For the delay, for example, KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. was used, and a value measured by a measurement angle of 0° and a measurement wavelength of 589.3 nm was set. Further, the retardation system uses two polarizing plates to obtain the refractive index direction (spindle direction) of the film, and the refractive index (n _x , ny) of the two axes orthogonal to the direction of the alignment axis is determined by an Abbe refractometer (adago). Company-made NAR-4T). Among them, an axis showing a larger refractive index is defined as a slow axis. The film thickness d (nm) was measured using an electric micrometer (manufactured by Anritsu Co., Ltd.), and the unit was converted into nm. The retardation can be calculated by the product of the refractive index difference (n _x -n _y ) and the thickness d (nm) of the film.

The difference between the refractive index n _{1x in} the slow axis direction of the light transmissive substrate 12 and the refractive index n _{1y in} the fast axis direction from the viewpoint of setting the retardation of the light transmissive substrate 12 to 3,000 nm or more (hereinafter _referred to as "refractive index difference Δn""Expression" is preferably 0.05 to 0.20. When the refractive index difference Δn is less than 0.05, the film thickness required to obtain the retardation value is increased. On the other hand, when the refractive index difference Δn exceeds 0.20, the light-transmitting substrate 12 is likely to be cracked or cracked, and the practicality as an industrial material is remarkably lowered. More preferably, the lower limit of the refractive index difference Δn is 0.07, and the upper limit of the refractive index difference Δn is 0.15. In addition, when the refractive index difference Δn exceeds 0.15, the durability of the light-transmitting substrate 12 may be deteriorated depending on the type of the light-transmitting substrate 12, and the durability of the light-transmitting substrate 12 in the moisture-heat resistance test may be inferior. From the viewpoint of ensuring excellent durability against the moist heat test, a more preferable upper limit of the refractive index difference Δn is 0.12.

Further, the refractive index n _{1x of the} light-transmitting substrate 12 in the slow axis direction dx is preferably 1.60 to 1.80, more preferably 1.65, and even more preferably 1.75. The refractive index n _{1y of the} light-transmitting substrate 12 in the fast axis direction dy is preferably 1.50 to 1.70, more preferably 1.55, and even more preferably 1.62 (1.65). The refractive index n _{1x of the} light-transmitting substrate 12 in the slow axis direction dx and the refractive index n _{1y of the} fast axis direction dy are within the above range, and satisfying the relationship of the refractive index difference Δn, thereby obtaining a better rainbow spot suppression effect. .

In the refractive index, the average reflectance (R) at a wavelength of 380 to 780 nm was measured using a spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation), and the obtained average reflectance (R) was defined by the following formula. The average reflectance (R) of the functional layer 15 is applied to a PET having a thickness of 50 μm which is not easily adhered to form a cured film having a thickness of 1 to 3 μm, and for the uncoated raw material composition of PET. In order to prevent back reflection, the surface (back surface) is thicker than a black vinyl tape (for example, yamato vinyl tape NO200-38-2138 mm width) having a width larger than the measurement point area, and the coating film can be measured. Average reflectivity. The refractive index of the light-transmitting substrate 12 is measured on the opposite side of the measurement surface, and the black vinyl tape is also attached. Further, the refractive index of the refractive index adjusting layer 13 can be measured by attaching a black vinyl tape to the opposite surface of the measuring surface of the laminated base material 11, that is, the light-transmitting substrate 12.

R(%)=(1-n) ² /(1+n) ²

Further, the refractive index and birefringence can also be measured using the above-described Abbe refractometer or "Oval Thickness Gauge M150" manufactured by JASCO Corporation. rate.

The method of measuring the refractive index n _x in the slow axis direction in the plane and the refractive index n _y in the fast axis direction in the plane is as follows. First, the alignment axis direction (the main axis direction, that is, the direction of the slow axis in the plane and the direction of the fast axis) of the measurement target (the light transmissive substrate 12 or the refractive index adjustment layer 13) is limited by using two polarizing plates. Next, a black vinyl tape (for example, yamato vinyl tape No. 200-38-21 38 mm width) was attached to the back surface of the measurement object, and a spectrophotometer (V7100 type, automatic absolute reflectance measuring unit, VAR-7010, Japan Spectrophotometer) was used. The condition of the polarization measurement is S-polarized light, and the reflectance when the vibration direction of the S-polarized light is parallel to the slow axis direction of the measurement target is measured five times, and the average value is calculated, and the vibration direction of the S-polarized light and the measurement target are fast. The reflectance when the axial directions were parallel was measured 5 times, and the average value was calculated. When the vibrational direction of the S-polarized light is parallel to the slow axis direction of the measurement target, the average value of the reflectance is expressed by the reflectance R (%) of the following equation, and the refractive index n _x of the slow axis direction of the measurement target can be obtained, and similarly, When the vibration direction of the S-polarized light is parallel to the fast axis direction of the measurement target, the average value of the reflectance is expressed by the reflectance R (%) of the following formula, and the refractive index n _{y of the} measurement object in the fast axis direction can be obtained.

R(%)=(1-n) ² /(1+n) ²

In the method of measuring the refractive index of the functional layer 15 after the laminate 10, for example, a cured film of each layer is cut out by a dicing blade or the like to prepare a sample (sampo) in a powder state, and a method according to JIS K7142 (2008) B (powder) can be used. Becke method for bulk or granular transparent materials (using a Cargille reagent with a known refractive index, placing the aforementioned powder state sample on glass) A tablet or the like is dropped onto the sample, and the sample is impregnated with the reagent. By observing the appearance by a microscope, the bright line generated in the outline of the sample by the difference in refractive index between the sample and the reagent; the Becke line becomes a method of visually observing the refractive index of the reagent as a method of the refractive index of the sample). Since the light-transmitting substrate 12 and the refractive index adjusting layer 13 have a difference in refractive index due to the direction, the black vinyl tape is attached to the treated surface of the laminated substrate 11 without using the Becke method, and the average reflectance is measured.

<Light Transmissive Substrate>

Next, the light-transmitting substrate 12 of the laminated substrate 11 will be described in detail. The light-transmitting substrate 12 is not particularly limited as long as it has a visible light transmittance substrate having at least an in-plane retardation. The light transmissive substrate 12 is, for example, a substrate made of polycarbonate, a cycloolefin polymer, acrylic acid, polyester or the like. Among them, the polyester substrate is preferred in terms of cost and mechanical strength. Hereinafter, a polyester substrate will be described as an example, and the light-transmitting substrate 12 having a birefringence in the plane will be described in more detail.

The material constituting the polyester substrate may be a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of the polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly(1,4-cyclohexyl dimethylene terephthalate). Formate), polyethylene-2,6-naphthalate. Further, the polyester for the polyester substrate may be a copolymer of the above polyester of the above or the like, or may be mainly composed of the above polyester (for example, a component of 80 mol% or more), and a small proportion (for example, 20 mol) Other than %) Resin blender. A polyester such as polyethylene terephthalate or polyethylene-2,6-naphthalate is preferred because it has a good balance between mechanical properties and optical properties. In particular, it is preferably composed of polyethylene terephthalate (PET). Polyethylene terephthalate is highly versatile and easy to obtain. Further, PET is excellent in transparency, heat or mechanical properties, and can control the retardation by the stretching process, and the intrinsic birefringence is large, and even if the film thickness is thin, it is relatively easy to have a large retardation.

In the method of obtaining the above-mentioned polyester base material, for example, a polyester such as PET of the above material is melted and extruded into a film-formed unstretched polyester, and at a temperature equal to or higher than the glass transition temperature, a stretcher or the like is used. After the lateral stretching, a method of heat treatment is applied. The above transverse stretching temperature is preferably from 80 to 130 ° C, more preferably from 90 to 120 ° C. Further, the lateral stretching ratio is preferably 2.5 to 6.0 times, more preferably 3.0 to 5.5 times. When the lateral stretching ratio exceeds 6.0 times, the transparency of the obtained polyester base material is liable to lower, and when the stretching ratio is less than 2.5 times, the stretching tension is also small, so that the birefringence of the obtained polyester base material is small, and the desired product is obtained. The retarded film thickness becomes thick. Further, when the polyester base material is extruded into a film shape, the flow direction (mechanical direction) is extended, in other words, the longitudinal direction may be extended. In this case, it is preferable that the value of the refractive index difference Δn is set to be within the above preferred range, and the longitudinal extension is preferably twice or less. Further, in the case of extrusion molding, in place of the longitudinal stretching, the lateral extension of the unstretched polyester may be carried out under the above conditions, and then longitudinally stretched. Further, the treatment temperature in the above heat treatment is preferably from 100 to 250 ° C, more preferably from 180 to 245 ° C.

Controlling the delay of the polyester substrate produced by the above method The method of 3000 nm or more is, for example, a method of appropriately setting the stretching ratio or the stretching temperature and the film thickness of the produced polyester substrate. Specifically, for example, the higher the stretching ratio, the lower the stretching temperature, or the thicker the film thickness, the easier it is to obtain a high retardation, the lower the stretching ratio, the higher the stretching temperature, or the thinner the film thickness, the easier it is to obtain. Delay.

The thickness of the above polyester substrate is preferably in the range of 15 to 500 μm. When the thickness is less than 15 μm, the retardation of the polyester base material is not more than 3,000 nm, and the anisotropy of mechanical properties is remarkable, and cracking, cracking, and the like are likely to occur, and the practicality as an industrial material may be remarkably lowered. On the other hand, when the thickness exceeds 500 μm, the polyester substrate is very straight, and the softness characteristic of the polymer film is lowered, and the practicality as an industrial material is also lowered, which is not preferable. A lower limit of the thickness of the polyester substrate is preferably 50 μm, a more preferred upper limit is 400 μm, and a more preferred upper limit is 300 μm.

Further, the transmittance of the light-transmitting substrate 12 in the visible light region is preferably 80% or more, and more preferably 84% or more. Further, the above transmittance can be measured by JIS K7361-1 (test method for total light transmittance of a plastic-transparent material).

The light-transmitting substrate 12 can be subjected to surface treatment such as saponification treatment, Glow Discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, and flame treatment as long as it does not deviate from the technical requirements of the present invention.

<refractive index adjustment layer>

Next, the refractive index adjusting layer 13 will be described in detail. The refractive index adjusting layer 13 is full One or more of the above conditions (a) to (i) reduce the refractive index difference existing at the interface between the light-transmitting substrate 12 and the functional layer 15, suppress reflection at the interface, and make the interference fringes inconspicuous. . The refractive index adjusting layer 13 is not particularly limited as long as it has a layer having in-plane birefringence and visible light transmittance. Further, the refractive index adjusting layer 13 may have a function of adjusting the refractive index between the light transmissive substrate 12 and the functional layer 15. For example, in the case of a primer, a more specific example is that the underlayer having a function as an easy-adhesion layer imparts an in-plane refractive index difference, so that the underlayer forms the refractive index adjusting layer 13.

The refractive index adjusting layer 13 having in-plane birefringence formed on the light-transmitting substrate 12 can be formed by orienting a molecule having a refractive index anisotropy (for example, a liquid crystal molecule) or a compound. The refractive index adjusting layer 13 is obtained by applying a composition containing a refractive index anisotropic molecule or a refractive index anisotropic compound to the light-transmitting substrate 12 and curing the composition. For example, when the light-transmitting substrate 12 is a stretched film or the like and contains a regular molecular alignment, the liquid crystal molecules applied to the light-transmitting substrate 12 may have a light-transmitting group in nature. The molecular alignment of the material 12 is aligned to correspond to the regularity. Thereby, the obtained refractive index adjusting layer 13 has in-plane birefringence corresponding to the birefringence of the light-transmitting substrate 12, and therefore the refractive index adjusting layer 13 can satisfy the above conditions (a) to (i). Further, the viewpoint of making the alignment of the refractive index anisotropy molecule or the refractive index anisotropy compound contained in the refractive index adjustment layer 13 more stable depends not only on the alignment of the light transmissive substrate 12 but also on the rubbing alignment. Or the light alignment causes the refractive index anisotropy molecule or the refractive index anisotropy compound contained in the refractive index adjustment layer 13 to be actively aligned.

Further, another method is to obtain a refractive index adjusting layer 13 having in-plane birefringence by extending the resin layer. In general, the conditions such as temperature are adjusted, and the layer composed of the resin is stretched, and the layer composed of the resin can exhibit in-plane birefringence. Therefore, the refractive index adjusting layer 13 is formed on the light-transmitting substrate 12 before stretching, and the light-transmitting substrate 12 and the refractive index adjusting layer 13 are simultaneously extended to impart birefringence to the light-transmitting substrate 12. At the same time, the refractive index adjusting layer 13 can be provided with birefringence corresponding to the birefringence of the light-transmitting substrate 12.

More specifically, first, the composition constituting the refractive index adjusting layer 13 is applied onto the light-transmitting substrate 12 before the stretching, and the composition is cured on the light-transmitting substrate 12 to obtain a refractive index. Adjust layer 13. As the material constituting the refractive index adjusting layer 13, a resin material which exhibits birefringence by extension can be widely used, and it is preferable that the affinity to the light-transmitting substrate 12 is high. A thermoplastic resin or a thermosetting polyester resin, a urethane resin, an acrylic resin, a modified body thereof, or the like can be used as the resin material constituting the refractive index adjusting layer 13. The above-mentioned various resin films can be used as the light-transmitting substrate 12 to which the composition of the refractive index adjusting layer 13 is applied. However, in the extrusion molding, a resin film which is stretched at a low magnification in the machine direction is preferable. The flatness of the light transmissive substrate 12 can be ensured by the extension of the mechanical direction (the extrusion direction at the time of extrusion of the light transmissive substrate 12), and thus can be formed on the light transmissive substrate 12. The refractive index adjusting layer 13 is uniformized.

Thereafter, the laminated substrate 11 containing the refractive index adjusting layer 13 formed on the light-transmitting substrate 12 and the light-transmitting substrate 12 is added. When it is heated to a temperature higher than the glass transition temperature, it extends in the transverse direction orthogonal to the machine direction. As described above, when the stretching ratio in the lateral direction is extremely large compared to the stretching ratio in the longitudinal direction, the extending axis of the light-transmitting substrate 12 is approximately in the lateral direction, and a specific example is a polyester terephthalate film. The slow axis of the light-transmitting substrate 12 is formed to extend approximately in the lateral direction. The refractive index adjusting layer 13 is extended only in the lateral direction. Therefore, even if the refractive index adjusting layer 13 is formed by a resin material which is more difficult to impart birefringence than the light transmissive substrate 12, a certain degree of birefringence corresponding to the light transmissive substrate 12 can be imparted. The birefringence of the anisotropy.

According to the above method, by imparting the birefringence stretching treatment to the light-transmitting substrate 12, it is possible to impart birefringence to the refractive index adjusting layer 13 not only to the light-transmitting substrate 12 but also to the refractive index adjusting layer 13. Further, since the light-transmitting substrate 12 and the refractive index adjusting layer 13 are heated in a state of being heated, the advantage of improving the adhesion between the light-transmitting substrate 12 and the refractive index adjusting layer 13 can be enjoyed.

Regarding the refractive indices n ₂ , n _2x , n _2y , n _2a , and n _2b (see FIGS. 3 and 4 ) of the refractive index adjusting layer 13 , as described above, the respective refractive indices n _{1 of the} light transmissive substrate 12 are as described above. The refractive indices n ₃ , n _3x , and n _{3y of} n _1x , n _{1y ,} and the functional layer 15 are associated with each other and can be appropriately set. For example, when the light-transmitting substrate 12 is composed of a polyethylene terephthalate film and the functional layer 15 functions as a hard coat layer, the refractive index n ₂ of the refractive index adjusting layer 13 can be set to 1.50 to 1.70. The refractive index n _2x of the refractive index adjusting layer 13 can be set to 1.55 to 1.75, the refractive index n _2y of the refractive index adjusting layer 13 can be set to 1.45 to 1.65, and the refractive index n _2a of the refractive index adjusting layer 13 can be set. The refractive index n _2b of the refractive index adjusting layer 13 can be set to 1.46 to 1.64, which is 1.51 to 1.69.

The thickness of the refractive index adjusting layer 13 may be 30 nm or more and 10 μm or less. When the thickness of the refractive index adjusting layer 13 is less than 30 nm, the uniformity of the refractive index adjusting layer 13 is lowered. Further, the upper limit of the thickness of the refractive index adjusting layer 13 is not particularly set as a function of the refractive index adjusting layer 13, but it is preferably set to 1 μm or less for industrial reasons.

The thickness of the refractive index adjusting layer 13 (at the time of hardening) is defined, for example, by an average value (nm) of measured values of any ten points obtained by observing the cross section of the refractive index adjusting layer 13 by an electron microscope (SEM, TEM, STEM). When the thickness of the refractive index adjusting layer 13 is very thin, the high magnification observer records in a photograph and can be measured by magnification. When zoomed in, the layer interface line is clearly known to the interface line, and the very thin line becomes a thick line. In this case, the center line portion in which the thick line width is divided into two equal parts may be measured as an interface line.

<Function layer, second function layer>

Next, the functional layer 15 and the second functional layer 17 will be described. The functional layer 15 and the second functional layer 17 are layers which are intended to exhibit a certain function in the film of the laminate 10, and specifically, for example, have functions such as hard coatability, antireflection property, antistatic property, and antifouling property. Floor. As described above, the number of the functional layers contained in the laminate 10 can be any number of layers or more, depending on the use of the laminate or the like. In the laminate 10 shown in Fig. 1, the functional layer 15 is formed of a hard coat layer formed on one surface of the laminated substrate 11. Further, in the laminate 10 shown in FIG. 2, the functional layer 15 is hard formed on one side of the laminated substrate 11. The second functional layer 17 is composed of a low refractive index layer formed on the surface opposite to the laminated substrate 11 of the hard coat layer. The hard coat layer as the functional layer 15 and the low refractive index layer as the second functional layer 17 will be described below.

"Hard coating layer" is a layer for improving the scratch resistance of an optical film. Specifically, it is a pencil hardness test (4.9 N load) prescribed in JIS K5600-5-4 (1999), and has a "H" or more. Hard layer. One example of the hard coat layer is a composition for forming a hard coat layer containing an ionizing radiation curable resin which is cured by ultraviolet rays or electron beams and a photopolymerization initiator, and is laminated on the laminated substrate 11 to be laminated. The base material 11 is obtained by hardening a composition for forming a hard coat layer. The hard coat layer obtained by this method is optically isotropic without having in-plane birefringence. Therefore, the refractive indices n ₃ , n _3x , and n _3y of the functional layer 15 composed of the hard coat layer are the same value. Specifically, the refractive indices n ₃ , n _3x , and n _3y of the functional layer 15 composed of the hard coat layer may be 1.45 to 1.65, respectively. The film thickness (hardening) of the hard coat layer is in the range of 0.1 to 100 μm, preferably 0.5 to 20 μm. The film thickness of the hard coat layer is a value measured by observing a cross section by an electron microscope (SEM, TEM, STEM).

The ionizing radiation-curable resin of the composition for forming a hard coat layer, for example, a compound having one or two or more unsaturated bonds, such as a compound having an acrylate-based functional group. Examples of the compound containing one unsaturated bond include ethyl (meth) acrylate, ethyl hexyl (meth) acrylate, styrene, methyl styrene, N-vinyl pyrrolidone and the like. a compound having two or more unsaturated bonds, such as polyhydroxyl Methylpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylic acid a polyfunctional compound of ester, dipentaerythritol hexa(meth) acrylate, 1,6-hexanediol di(meth) acrylate, neopentyl glycol di(meth) acrylate or the above polyfunctional compound A reaction product such as an acrylate or the like (for example, a poly(meth)acrylate having a polyhydric alcohol) or the like. In the present specification, "(meth) acrylate means methacrylate and acrylate.

In addition to the above compounds, a lower molecular weight polyester resin having an unsaturated double bond, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, a acetal resin, a polybutadiene resin A polythiol polyolefin resin or the like can also be used as the above ionizing radiation curing resin.

The ionizing radiation-curable resin can be used in combination with a solvent-drying resin (a thermoplastic resin or the like, which is obtained by drying a solvent added to adjust the solid content during coating to form a resin). By using a solvent-drying resin in combination, it is possible to effectively prevent film defects on the coated surface. The solvent-drying type resin which can be used together with the above-mentioned ionizing radiation-curable resin is not particularly limited, and a thermoplastic resin can be generally used. The thermoplastic resin is not particularly limited, and examples thereof include a styrene resin, a (meth)acrylic resin, a vinyl acetate resin, a vinyl ether resin, a halogen-containing resin, an alicyclic olefin resin, and a polycarbonate resin. A polyester resin, a polyamide resin, a cellulose derivative, a polyoxyxylene resin, a rubber or an elastomer. The above thermoplastic resin is generally non-crystalline and soluble in organic solvents (especially A resin which can dissolve a plurality of polymers or a common solvent of a curable compound is preferred. In particular, from the viewpoints of film formability, transparency, and weather resistance, a styrene resin, a (meth)acrylic resin, an alicyclic olefin resin, a polyester resin, and a cellulose derivative (cellulose) are preferred. Esters, etc.).

Moreover, the composition for forming a hard coat layer may contain a thermosetting resin. The thermosetting resin is not particularly limited, and examples thereof include a phenol resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, an unsaturated polyester resin, a polyurethane resin, and an epoxy resin. Resin, amino alkyd resin, melamine-urea co-condensation resin, enamel resin, polydecane resin, and the like.

The photopolymerization initiator is not particularly limited, and a known one can be used, for example, the above photopolymerization initiator, and specific examples thereof include acetophenones, benzophenones, and M. benzoyl benzoate (Michler- Benzoyl benzoate), α-amyloxime esters, thioxanthones, propofols, biphenyls, benzoin, fluorenylphosphine oxides. A photosensitizer is preferably used in combination, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

When the above-mentioned polymerization initiator is a resin having a radical polymerizable unsaturated group as described above, it is preferred to use acetophenone, benzophenone, thioxanthone alone or in combination. Benzoinine, benzoin methyl ether, etc. Further, when the ionizing radiation-curable resin has a resin having a cationically polymerizable functional group, the photopolymerization initiator may be an aromatic diazonium salt, an aromatic sulfonium salt or an aromatic sulfonium salt, either singly or in the form of a mixture. , metallocene compound, benzoin sulfonate Or a mixture thereof, and the like.

The content of the photopolymerization initiator in the composition for forming a hard coat layer is preferably from 1 to 10 parts by mass based on 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 laminate 10 cannot be sufficiently hard. When the amount exceeds 10 parts by mass, the ionizing radiation cannot reach the deep portion of the coated film, and the internal hardening may not be promoted. The lower limit of the content of the photopolymerization initiator is preferably 2 parts by mass, and more preferably the upper limit is 8 parts by mass. When the content of the photopolymerization initiator is within this range, a hardness distribution does not occur in the film thickness direction, and uniform hardness can be easily formed.

The composition for forming a hard coat layer may contain a solvent. The solvent may be selected and used in combination with the type and solubility of the resin component used, and examples thereof include ketones (acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, diacetone alcohol, etc.), Ethers (dioxane, tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, two) Toluene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (ethanol, isopropanol, butanol, Cyclohexanol, etc.), cellosolve (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetate, fluorene (dimethyl hydrazine, etc.), guanamine (dimethyl A mixed solvent such as carbamide, dimethylacetamide or the like may be used.

The content ratio (solid content) of the raw material in the composition for forming a hard coat layer is not particularly limited, and is usually 5 to 70% by mass, which is particularly preferable. It is 25 to 60% by mass.

The composition for forming a hard coat layer may be added to a conventionally known dispersant, surfactant, antistatic agent, or decane for the purpose of improving the hardness of the hard coat layer, suppressing the shrinkage, controlling the refractive index, and imparting anti-glare properties. Coupling agents, tackifiers, anti-colorants, colorants (pigments, dyes), defoamers, flat agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, Easy to slip agent, etc.

The above-mentioned composition for forming a hard coat layer may be a mixture of a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

The method for preparing the composition for forming a hard coat layer is not particularly limited as long as the components can be uniformly mixed. For example, a known device such as a paint shaker, a bead mill, a kneader, or a mixer is used.

Further, the method of applying the composition for forming a hard coat layer to the laminated base material 11 is not particularly limited, and examples thereof include a spin coating method, a dipping method, a spray method, a die coating method, and a bar coating method. A known method such as a roll coating method, a meniscus-coating method, a lithography method, a gravure printing method, or a liquid coating method.

The coating film formed by applying the composition for forming a hard coat layer to the laminated base material 11 is preferably cured by heating and/or drying, irradiation with an active energy ray or the like.

The above active energy ray irradiation is, for example, irradiation by ultraviolet rays or electron beams. Specific examples of the ultraviolet source include a high-pressure mercury lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a carbon arc lamp, a black lamp fluorescent lamp, and a metal halide lamp. Also, the wavelength of ultraviolet rays can use waves of 190 to 380 nm. Long area. Specific examples of the electron source are Cockcroft-Walton type, van de Graaff type, resonant transformer type, insulated core transformer type, or linear type, Dynamitron type, high Various electron line accelerators such as frequency type.

Next, the low refractive index layer is a layer which has a function of lowering the reflectance when external light (for example, a fluorescent lamp, natural light, or the like) is reflected on the surface of the laminate 10. The low refractive index layer has a small refractive index at the bottom of the hard coat layer and is larger than air. Specifically, the refractive index of the low refractive index layer is preferably in the range of 1.1 to 2.0, more preferably in the range of 1.2 to 1.8, still more preferably in the range of 1.3 to 1.6. When the refractive index of the low refractive index layer is within the above range, it can be effectively prevented from being reflected on the laminate 10. Further, the refractive index of the low refractive index layer may be changed from the inner side of the laminate 10 to the surface side of the laminate 10 in the low refractive index layer, and the refractive index gradually changes toward the refractive index of the air.

The material for the low refractive index layer is not particularly limited as long as it can form a low refractive index layer having the above refractive index, and for example, a resin material described in the above composition for forming a hard coat layer is preferable. Further, the low refractive index layer may have a refractive index adjusted by containing a polyfluorene-containing co-polymer, a fluorine-containing copolymer, and fine particles in addition to the resin material. The above-mentioned polyoxymethylene-containing copolymer may, for example, contain a polyoxyethylene vinylene copolymer. Further, a specific example of the fluorine-containing copolymer is a copolymer obtained by copolymerizing a monomer composition of fluorinated vinylidene and hexafluoropropane. Further, the fine particles include, for example, cerium oxide fine particles, acrylic fine particles, styrene fine particles, acrylic styrene copolymerized fine particles, and fine particles having voids. Further, "a microparticle having a void" means that the inside of the formed microparticle is filled with The structure of the gas and/or the porous structure containing the gas is a particle which is inversely proportional to the occupation ratio of the gas in the fine particles and which lowers the refractive index than the original refractive index of the fine particles.

Further, the above display shows that the functional layer 15 is composed of a hard coat layer, and the second functional layer 17 is composed of a low refractive index layer. However, the present invention is not limited to these examples, and the laminate 10 is composed of a hard coat layer and a low refractive index layer. At least one of the hard coat layer and the low refractive index layer may be contained in at least one of the layers, and may have a layer having another function such as an electric resistance preventing layer, an antiglare layer, or an antifouling layer.

The antistatic layer can be formed, for example, by including an antistatic agent in the composition for forming a hard coat layer. As the antistatic agent, a conventionally known one can be used, and for example, a cationic antistatic agent such as a quaternary ammonium salt or a fine particle such as tin-doped indium oxide (ITO) or a conductive polymer can be used. When the above antistatic agent is used, the content thereof is preferably from 1 to 30% by mass based on the total mass of the total solid content.

Further, the antiglare layer can be formed, for example, by including an antiglare agent in the composition for forming a hard coat layer. The antiglare agent is not particularly limited, and various inorganic or organic fine particles can be used. The average particle diameter of the fine particles is not particularly limited, and is generally about 0.01 to 20 μm. Further, the shape of the fine particles may be any of a true spherical shape and a rounded shape, and is preferably a true spherical shape.

When the fine particle system exhibits anti-glare properties, it is preferably transparent fine particles. Specific examples of such fine particles include inorganic cerium oxide beads, for example, and organic beads such as plastic beads. Specific examples of the above plastic beads include, for example, styrene beads (refractive index 1.60) and melamine beads (refracting Rate 1.57), acrylic beads (refractive index 1.49), acrylic-styrene beads (refractive index 1.54), polycarbonate beads, polyethylene beads, and the like.

The antifouling layer serves as a layer in which dirt (fingerprint, water-based or oily ink, pencil, etc.) is not easily applied to the outermost surface of the liquid crystal display device, or is easy to wipe even if it adheres. Further, by the formation of the above antifouling layer, the antifouling property and the scratch resistance can be improved for the liquid crystal display device. The antifouling layer can be formed, for example, by a composition containing an antifouling agent and a resin.

The anti-fouling agent is mainly intended to prevent contamination of the outermost surface of the liquid crystal display device, and the scratch resistance can be imparted to the liquid crystal display device. The anti-pollution agent may be, for example, a fluorine-based compound, an anthraquinone-based compound, or a mixed compound thereof. More specifically, for example, a fluorinated alkyl decane coupling agent such as 2-perfluorooctylethyltriamine decane or the like is used, and it is particularly preferable to use an amine group. The resin is not particularly limited, and for example, there is a resin material exemplified as the composition for forming a hard coat layer.

The above antifouling layer can be formed, for example, on the above hard coat layer. It is particularly preferable that the antifouling layer is formed on the outermost surface. For example, the above antifouling layer can also be replaced by imparting antifouling properties to the hard coat layer itself.

<About laminated substrate and laminate>

According to the embodiment, when the laminated base material 11 and the laminated body 10 described above are provided, the functional layer 15 provided on the laminated base material 11 and the light-transmitting base material 12 of the laminated base material 11 are provided with refraction. Rate adjustment layer 13. The refractive index of the refractive index adjusting layer 13 has in-plane birefringence, and is also along the slow axis direction dx of the light transmissive substrate 12 having in-plane birefringence. The refractive index in both directions of the axial direction dy is adjusted between the light-transmitting substrate 12 and the functional layer 15. More specifically, there is no optical interface in which the refractive index of the light-transmitting substrate 12 in the slow axis direction dx greatly changes between the light-transmitting substrate 12 and the functional layer 15, and there is no light-transmitting substrate. The optical interface of the 12th axis of the fast axis direction dy will vary greatly. In other words, there is no interface between the light-transmitting substrate 12 and the functional layer 15 because the refractive index difference is large and the reflectance is high. Therefore, it is possible to effectively prevent the light from entering the laminated body 10 from the side of the functional layer 15, but the light is reflected before reaching the light-transmitting substrate 12 having in-plane birefringence. Thereby, the interference light which can be recognized by the light reflected on the surface of the laminated body 10 and the light reflected inside the laminated body 10 by interference can be effectively made inconspicuous.

Further, the retardation of the light-transmitting substrate 12 is set to 3,000 nm or more, so that rainbow spots are not noticeable. Therefore, in accordance with the laminated substrate 11 and the laminate 10 described herein, it is effective to prevent both the rainbow spots and the interference fringes from being conspicuous.

Further, when the refractive index adjusting layer 13 is realized by the underlayer, there is no increase in the substantial material cost or an increase in the number of manufacturing steps, and the above-described useful effects can be ensured. However, the thickness is not limited to such an example, and at least one of the light-transmitting substrate 12 and the refractive index adjusting layer 13 and between the refractive index adjusting layer 13 and the functional layer 15 is different from the refractive index adjusting layer 13 in thickness. The bottom layer is less than 30nm. When the underlayer having a thickness of less than 30 nm is provided, the effect of the interference fringes generated by the refractive index adjusting layer 13 is not sufficiently exhibited, and for example, the adhesive effect due to the underlayer can be expected.

Polarizer

The laminated base material 11 and the laminated body 10 are used, for example, in combination with the polarizing plate 20. Fig. 5 is a schematic configuration diagram of a polarizing plate 20 combined with the laminate 10 and the laminated substrate 11 shown in Fig. 1 . As shown in FIG. 5, the polarizing plate 20 is provided with the laminated body 10, the polarizing element 21, and the protective film 22. The polarizing element 21 is formed on a surface on the side opposite to the surface on which the functional layer 15 on which the laminated substrate 11 is formed, on which the light-transmitting substrate 11 is formed. The protective film 22 is provided on the surface opposite to the surface on which the laminated body 10 of the polarizing element 21 is provided. The protective film 22 may also be a retardation film.

The polarizing element 21 is, for example, dyed with iodine or the like, and a polyvinyl alcohol film, a polyvinyl acetal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, or the like which has been stretched.

"Liquid Crystal Display Panel"

The laminated base material 11, the laminated body 10, and the polarizing plate 20 are used in combination with a liquid crystal display panel. Fig. 6 is a schematic configuration diagram of a liquid crystal display panel 30 in which the laminate 10 and the laminated substrate 11 shown in Fig. 1 and the polarizing plate 20 shown in Fig. 5 are combined.

The liquid crystal display panel shown in FIG. 6 has a protective film 31, a polarizing element 32, and a phase which are laminated with a triacetyl cellulose film (TAC film) or the like from the light source side (backlight unit side) toward the viewer side. The structure of the poor film 33, the adhesive layer 34, the liquid crystal cell 35, the adhesive layer 36, the retardation film 37, the polarizing element 21, and the laminate 10. liquid The unit cell 35 is a liquid crystal layer, an alignment film, an electrode layer, a color filter, or the like disposed between two glass substrates.

The retardation films 33 and 37 are, for example, a triethylenesulfonated cellulose film or a cycloolefin polymer film. The retardation film 37 can also be the same as the protective film 22. The adhesive constituting the adhesive layers 34, 36 is, for example, a pressure sensitive adhesive (PSA).

Image Display Device

The laminated substrate 11, the laminate 10, the polarizing plate 20, and the liquid crystal display panel 30 can be used in combination with an image display device. The image display device includes, for example, a liquid crystal display (LCD), a cathode ray tube display device (CRT), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), a touch panel, a tablet PC, Electronic paper, etc. 7 is a liquid crystal display in which an example of the image display device 40 of the laminate 10 and the laminated substrate 11 shown in FIG. 1, the polarizing plate 20 shown in FIG. 5, and the liquid crystal display panel 30 shown in FIG. The schematic composition of the figure.

The image display device 40 shown in Fig. 7 is a liquid crystal display. The image display device 30 is composed of a backlight unit 41 and a liquid crystal panel 30 having a laminate 10 disposed closer to the viewer than the backlight unit 41. The backlight unit 41 can use a conventional backlight unit.

"Other uses"

Further, the laminated base material 11 and the laminated body 10 are used for applications other than the use of the laminated display unit 30 directly on the display surface of the image display device 30, for example, The touch panel sensor is disposed on the image display device 30. In this example, a touch panel device formed by laminating the substrate 11 or the laminate 10 directly or indirectly on the touch panel sensor is prepared, and the touch panel device can also be disposed on the image. On the display device.

Further, the laminated base material 11 and the laminated body 10 can be used for various purposes for avoiding the occurrence of interference fringes. For example, the laminated base material 11 and the laminated body 10 can be used as a window material of a display part of a machine such as a clock or an instrument.

[Examples]

In order to explain the present invention in detail, the following examples are described, but the invention is not limited thereto.

The laminates of Examples 1 and 2 and Comparative Example 1 were produced as described below. For each of the fabricated laminates, the occurrence of interference fringes and the occurrence of rainbow spots were examined.

(Example 1)

The polyethylene terephthalate material was melted at 290 ° C, formed into a mold by a film, extruded into a film, adhered to a water-cooled cooled rotary quench drum, and cooled to form an unstretched film. The unstretched film was preheated at 120 ° C for 1 minute using a biaxial stretching test apparatus (Toyo Seiki), and then extended to a stretching ratio of 4.5 times at 120 ° C, and then extended at a stretching angle of 90 degrees with the extending direction. The film was stretched 1.5 times to obtain a light-transmitting substrate having n _1x = 1.70, n _1y = 1.60, a film thickness of 80 μm, and a retardation of 8000 nm.

On the light-transmitting substrate, the photopolymerizable liquid crystal compound was dissolved in a mixed solvent of cyclohexanone and n-propanol (solvent ratio: 9:1) by 20% by mass, and 5% photopolymerization was added with respect to the solid content. The ink of Irg 184 (Ciba Specialty Chemicals Co., Ltd.) was applied by a bar coater to have a film thickness after drying of 0.5 μm. Next, the solvent was dried by heating at 70 ° C for 4 minutes, and the photopolymerizable liquid crystal compound was aligned, and the coated surface was irradiated with ultraviolet rays to immobilize the photopolymerizable liquid crystal compound, and n _2x = 1.60, n _2y = A refractive index adjustment layer of 1.55.

Next, an optically isotropic pentaerythritol triacrylate (PETA) as a functional layer was dissolved in a MIBK solvent by 30% by mass, and a 5% photopolymerization initiator Irg184 (Ciba Specialty Chemicals) was added to the solid portion. The ink was applied by a bar coater to a film thickness of 5 μm after drying. Next, the solvent was dried by heating at 70 ° C for 2 minutes, and then the coated surface was irradiated with ultraviolet rays, immobilized, and a functional layer of n _3x = n _3y = 1.50 was laminated to obtain a laminate of Example 1.

(Example 2)

The polyethylene terephthalate material was melted at 290 ° C, formed into a mold by a film, extruded into a sheet, adhered to a water-cooled cooled rotary quench drum, and cooled to form an unstretched film. The unstretched film was preheated at 120 ° C for 1 minute using a biaxial stretching test apparatus (Toyo Seiki), and then extended to a stretching ratio of 4.5 times at 120 ° C, and then extended at a stretching angle of 90 degrees with the extending direction. The film was stretched 1.5 times to obtain a light-transmitting substrate having n _1x = 1.70, n _1y = 1.60, a film thickness of 33 μm, and a retardation of 3,300 nm. A refractive index adjusting layer and a functional layer were formed in the same manner as in Example 1 on the obtained light-transmitting substrate, and the laminate of Example 2 was obtained. In other words, the laminate of Example 2 and the laminate of Example 1 have different thicknesses in the light-transmitting substrate.

(Comparative Example 1)

A laminate of Comparative Example 1 was produced in the same manner as the laminate of Example 1 except that an intermediate layer composed of pentaerythritol triacrylate: ruthenium pentoxide = 7:3 was used instead of the refractive index adjustment layer of Example 1. . The intermediate layer of the laminate of Comparative Example 1 is optically isotropic, and n _2x = n _2y = 1.575.

(Reference example 1)

The polyethylene terephthalate material was melted at 290 ° C, formed into a mold by a film, extruded into a sheet, adhered to a water-cooled cooled rotary quench drum, and cooled to form an unstretched film. The unstretched film was preheated at 120 ° C for 1 minute using a biaxial stretching test apparatus (Toyo Seiki), and then extended to a stretching ratio of 4.5 times at 120 ° C, and then extended at a stretching angle of 90 degrees with the extending direction. The film was stretched 1.5 times to obtain a light-transmitting substrate having n _1x = 1.70, n _1y = 1.60, a film thickness of 28 μm, and a retardation of 2800 nm. A refractive index adjusting layer and a functional layer were formed in the same manner as in Example 1 on the obtained light-transmitting substrate, and the laminate of Reference Example 1 was obtained. In other words, the laminate of Example 2 and the laminate of Example 1 have different thicknesses in the light-transmitting substrate.

(Measurement of refractive index and retardation of light through the substrate)

The refractive index and retardation of light transmitted through the substrate were determined as follows. First, the extended light is transmitted through the substrate using two polarizing plates to obtain the refractive index direction (nx, ny) of the two axes orthogonal to the alignment axis direction with respect to the alignment axis direction, by Abbe A refractometer (NAR-4T manufactured by Adago Co., Ltd.) was obtained. The axis in which the larger refractive index is displayed is defined as the slow axis. The film thickness d (nm) was measured using an electric micrometer (manufactured by Anritsu Co., Ltd.), and the unit was converted into nm. The retardation can be calculated by the product of the refractive index difference (n _{1x -} n _1y ) and the thickness d (nm) of the film.

(Measurement of refractive index of refractive index adjusting layer)

The refractive index of the refractive index adjusting layer was measured as follows. In the case of the photopolymerizable liquid crystal compound used in Examples 1 and 2, the polyimide film of the alignment film material was applied onto an optically isotropic glass substrate, and rubbing treatment was applied. The photopolymerizable liquid crystal compound was dissolved in a mixed solvent of cyclohexanone and n-propanol (solvent ratio: 9:1) by a spin coater to dissolve 20% by mass of the ink, and applied to the substrate to be dried. The film thickness afterwards becomes 1 um. Then, the photopolymerizable liquid crystal compound is aligned by heating at 70 ° C for 4 minutes, and the photopolymerizable liquid crystal compound is irradiated, and the refractive index adjusting layer obtained by immobilizing the photopolymerizable liquid crystal compound to the coated surface is used. The refractive index was measured by the same method as the substrate.

(Judge whether there is birefringence)

Whether or not there is a birefringence system is judged as follows. KOBRA-WR was used to set the measurement angle of 0° and the measurement wavelength was 589.3 nm, and the in-plane phase difference was measured. The in-plane phase difference of less than 20 nm was judged to have no birefringence, and those of 20 nm or more were judged to have birefringence.

(Measurement of refractive index of an isotropic material)

The refractive index of the isotropic material (intermediate layer and functional layer) was measured by an Abbe refractometer (NAR-4T manufactured by Adago Co., Ltd.).

(interference fringe evaluation)

The occurrence of interference fringes of each laminate was evaluated as follows.

The presence or absence of interference fringes of the obtained anti-glare film was visually inspected using an interference fringe inspection lamp (sodium lamp) manufactured by ANATECH Co., Ltd., and evaluated according to the following criteria. The obtained anti-glare film was applied to the opposite side of the coated surface with a black ink, and the coated surface was irradiated with an interference fringe inspection lamp to be evaluated by reflection observation.

○: Although interference fringes were observed, they were extremely thin, and there was no problem in practical use.

×: Obvious interference fringes were observed.

(Rainbow Spot Review)

The occurrence of rainbow spots of each sample was evaluated as follows. Each laminated substrate is placed on the observer side of an LED-backlit liquid crystal monitor (FLATORON IPS226V (manufactured by LG Electronics Japan)) A liquid crystal display device was fabricated on the polarizing element. The angle between the slow axis of the polyester substrate and the absorption axis of the polarizing element on the viewer side of the liquid crystal monitor was 45°. In the dark and in the bright place (illuminance 400 lux around the liquid crystal monitor), the image was observed by the front and the oblique direction (about 50 degrees) visually and through the polarized sunglasses, and the presence or absence of the rainbow spot was evaluated based on the following criteria. The observation system through polarized sunglasses is a very strict evaluation method than visual observation. The observation system was carried out in 10 people, and the evaluation was performed as the observation result.

◎: no rainbow spots were observed

○: Although rainbow spots are observed, there is no problem in practical use.

×: A strong rainbow spot was observed

The evaluation results of interference fringes and rainbow spots are shown in Table 1.

10‧‧‧Layer

11‧‧‧Laminated substrate

12‧‧‧Light transmissive substrate

13‧‧‧Refractive index adjustment layer

15‧‧‧ functional layer

Claims (17)

A laminated base material which is a laminated base material which forms a functional layer on one surface and which is a laminated body, and is characterized in that it has a light transmissive base material having in-plane birefringence and a light transmissive base. a refractive index adjusting layer having an in-plane birefringence and having a refractive index adjusting layer between the light-transmitting substrate and the functional layer, wherein the light-transmitting substrate has the largest refractive index in the plane The direction of the refractive index n _1x in the slow axis direction, the refractive index n _2x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmissive substrate, and the slow axis of the light transmissive substrate The refractive index n _{3x of the} functional layer in the direction parallel to the direction satisfies the relationship of n _1x <n _2x <n _3x or n _1x >n _2x >n _3x , which is orthogonal to the aforementioned slow axis direction of the light transmissive substrate. a refractive index n _{1y in the} axial direction, a refractive index n _2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light transmissive substrate, and a direction parallel to the fast axis direction of the light transmissive substrate The refractive index n _{3y of the} aforementioned functional layer satisfies n _1y < a relationship of n _2y <n _3y or n _1y >n _2y >n _3y , wherein a refractive index n _2x of the refractive index adjusting layer in a direction parallel to the slow axis direction of the light transmissive substrate, and the light transmission The refractive index n _2y of the refractive index adjusting layer in the parallel direction of the fast axis direction of the substrate satisfies the relationship of n _2x >n _2y , wherein the refractive index n _{1x of the} light-transmitting substrate in the slow axis direction and the light a refractive index n _{1y in the} fast axis direction of the transparent substrate, a refractive index n _2x of the refractive index adjusting layer in a direction parallel to the slow axis direction of the light transmissive substrate, and a light transmissive substrate The refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction satisfies the relationship of (n _{1x -} n _1y ) > (n _{2x -} n _2y ). A laminated base material which is a laminated base material which forms a functional layer on one surface and which is a laminated body, and is characterized in that it has a light transmissive base material having in-plane birefringence and a light transmissive base. a refractive index adjusting layer having an in-plane birefringence and having a refractive index adjusting layer between the light-transmitting substrate and the functional layer, wherein the light-transmitting substrate has the largest refractive index in the plane The direction of the refractive index n _1x in the slow axis direction, the refractive index n _2x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmissive substrate, and the slow axis of the light transmissive substrate The refractive index n _{3x of the} functional layer in the direction parallel to the direction satisfies the relationship of n _1x <n _2x <n _3x or n _1x >n _2x >n _3x , which is orthogonal to the aforementioned slow axis direction of the light transmissive substrate. a refractive index n _{1y in the} axial direction, a refractive index n _2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light transmissive substrate, and a direction parallel to the fast axis direction of the light transmissive substrate The refractive index n _{3y of the} aforementioned functional layer satisfies n _1y < a relationship of n _2y <n _3y or n _1y >n _2y >n _3y , wherein the refractive index n _{1x in the} slow axis direction of the light transmissive substrate is parallel to the slow axis direction of the light transmissive substrate The refractive index n _2x of the refractive index adjusting layer in the direction and the refractive index n _{3x of the} functional layer in a direction parallel to the slow axis direction of the light transmitting substrate satisfy n ₂ = (n _2x + n _2y )/2 And the relationship of |n _2x -(( n _1x +n _3x )/2)|<|n ₂ -((n _1x +n _3x )/2)|, in the aforementioned fast-axis direction of the light-transmitting substrate a refractive index n _1y , a refractive index n _2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light transmissive substrate, and a functional layer parallel to the fast axis direction of the light transmissive substrate The refractive index n _3y satisfies n ₂ =(n _2x +n _2y )/2, and |n _2y -((n _1y +n _3y )/2)|<|n ₂ -((n _1y +n _3y )/ 2) The relationship of |. The laminated substrate according to claim 1 or 2, wherein when the laminated substrate is observed in a normal direction, the slow axis direction of the light transmissive substrate and the refractive index in the refractive index adjusting layer The maximum direction, that is, the angle formed by the slow axis direction of the refractive index adjusting layer is less than 45°. The laminated substrate according to claim 1 or 2, wherein the slow axis direction of the light transmissive substrate and the maximum refractive index direction in the refractive index adjusting layer, that is, the slow axis direction of the refractive index adjusting layer parallel. A laminated base material which is a laminated base material which forms a functional layer on one surface and which is a laminated body, and is characterized in that it has a light transmissive base material having in-plane birefringence and a light transmissive base. a refractive index adjusting layer having an in-plane birefringence and having a refractive index adjusting layer between the light-transmitting substrate and the functional layer, wherein the light-transmitting substrate has the largest refractive index in the plane The direction of the refractive index n _1x in the slow axis direction, the refractive index n _2x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmissive substrate, and the slow axis of the light transmissive substrate The refractive index n _{3x of the} functional layer in the direction parallel to the direction satisfies the relationship of n _1x <n _2x <n _3x or n _1x >n _2x >n _3x , which is orthogonal to the aforementioned slow axis direction of the light transmissive substrate. a refractive index n _{1y in the} axial direction, a refractive index n _2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light transmissive substrate, and a direction parallel to the fast axis direction of the light transmissive substrate The refractive index n _{3y of the} aforementioned functional layer satisfies n _1y < a relationship between n _2y <n _3y or n _1y >n _2y >n _3y , wherein when the laminated base material is observed in a normal direction, the slow axis direction of the light-transmitting substrate and the refractive index adjustment layer are The maximum direction of the refractive index, that is, the angle formed by the slow axis direction of the refractive index adjusting layer is less than 45°, and the refractive index n _{1x of the} slow-axis direction of the light-transmitting substrate and the light-transmitting group a refractive index n _{1y in the} fast axis direction of the material, a refractive index maximum direction in the refractive index adjustment layer, that is, a refractive index n _{2a in} the slow axis direction of the refractive index adjusting layer, and the aforementioned slow axis of the refractive index adjusting layer The refractive index n _{2b in} the fast axis direction of the refractive index adjusting layer orthogonal to the direction satisfies the relationship of (n _{1x -} n _1y ) > (n _{2a -} n _2b ). The laminated substrate of claim 1, 2 or 5, wherein the laminated substrate has a retardation of 3000 nm or more. The laminated substrate of claim 1, 2 or 5, wherein the light transmissive substrate has a retardation of 3000 nm or more. A laminate comprising a laminated substrate according to claim 1, 2 or 5, and a functional layer formed on one surface of the laminated substrate, wherein the refractive index adjusting layer is located at the light transmissive group Between the material and the aforementioned functional layer. The laminate of claim 8 wherein the functional layer is a hard coat layer. A laminate according to claim 8 which further comprises a second functional layer provided on the opposite side of the laminated substrate on the functional layer. The laminate of claim 10, wherein the second functional layer is a low refractive index layer having a lower refractive index than the functional layer. A polarizing plate characterized by comprising a polarizing element and a laminated substrate according to item 1, 2 or 5 of the patent application. A liquid crystal display panel characterized by comprising a laminated substrate according to the first, second or fifth aspect of the patent application. An image display device characterized by the laminated substrate of claim 1, 2 or 5. A polarizing plate characterized by comprising a polarizing element and a laminate according to item 8 of the patent application. A liquid crystal display panel characterized by having a laminate as in claim 8 of the patent application. An image display device characterized by having a patent application A laminate of the eighth item.