TWI654085B - Laminated body, polarizing plate, liquid crystal panel, touch panel sensor, touch panel device and image display device - Google Patents

Abstract

The present invention is a laminate (10) comprising: a light-transmitting substrate (12); adjacent to the light-transmitting substrate, laminated to an intermediate layer (13) of an optical transparency substrate Adjacent to the intermediate layer, the functional layer (15) of the intermediate layer is laminated on the opposite side of the light-transmitting substrate. The average in-plane refractive index of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the average refractive index of the surface of the functional layer satisfies n ₃ n ₁ <n ₂ <n ₃ Or n ₁ >n ₂ >n ₃ . The thickness t [nm] of the intermediate layer, the wavelength λ _ave between the shortest wavelength λ _min of visible light and the longest wavelength λ _max of visible light, and the average refractive index n _{2 in} the plane of the intermediate layer satisfy λ _ave /(6×n ₂ ) < t < λ _ave / (3 × n ₂ ).

Description

Laminated body, polarizing plate, liquid crystal panel, touch panel sensor, touch panel device and image display device

The invention relates to a laminate, a polarizing plate, a liquid crystal panel, a touch panel sensor, a touch panel device and an image display device.

An image display surface in an image display device such as 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), or the like, usually A laminate having a functional layer that is expected to perform the desired function is provided directly or interposed between other members (for example, a touch panel sensor). Typical functional layers are, for example, hard coating layers for the purpose of improving scratch resistance.

The laminate typically has a light transmissive substrate that supports the functional layer. Such a lamination system interferes with the light reflected on the surface of the functional layer and the light reflected at the interface between the functional layer and the translucent substrate due to the difference in refractive index between the translucent substrate and the functional layer. It is a problem of the iridescent pattern of interference fringes.

Interference fringe countermeasures, for example, have been successfully formed on a light-transmitting substrate In the energy layer, the functional layer component is impregnated into the upper portion of the light-transmitting substrate, and the component of the light-transmitting substrate and the functional layer are mixed in the vicinity of the interface with the functional layer of the light-transmitting substrate. A mixed existence region exists (refer to, for example, JP2003-131007A). When the mixed region is present, the refractive index interface between the light-transmitting substrate and the functional layer can be alleviated. Therefore, by providing the mixed existence region, the reflectance at the interface between the light-transmitting substrate and the functional layer can be reduced, and interference fringes can be prevented from occurring.

However, in order to prevent the occurrence of interference fringes, it is necessary to form a mixed existence region having a sufficient thickness. Further, since the mixed region is soft, when a mixed existence region having a sufficient thickness is formed, in order to impart hardness to the laminate, it is necessary to thicken the functional layer on the mixed region. Therefore, the countermeasure against the use of the mixed existence region is required to apply a thick composition for a functional layer on the light-transmitting substrate, which causes another problem of an increase in manufacturing cost. Further, a light-transmitting substrate which can form a mixed existence region is represented by a triethylenesulfonated cellulose substrate, and has high moisture permeability. Further, it is possible to form a substrate having a high moisture permeability in a mixed existence region, and the deformation of the function is reduced as the humidity of the environment changes.

A recent tendency is, for example, as disclosed in JP 2011-107198 A, the retardation of the rainbow plaque can be eliminated by adjusting the retardation, so that the light-transmitting substrate of the anti-glare film is not only an optical isotropic substrate but also an optical anisotropy. Substrate. However, the extended polyester substrate of a typical optically anisotropic substrate is less likely to form a mixed presence region. In other words, the interference fringe countermeasure using the mixed existence region becomes unsuitable for use in all of the transparent substrates that can be assembled to the laminate.

Further, a laminate called an anti-glare film can form irregularities on the outermost surface (see, for example, JP 2011-81118 A), so that external light can be diffused. Therefore, the lamination system called an anti-glare film can make the interference fringes invisible by the diffusion of the unevenness on the outermost surface, so that it is not necessary to provide a mixed existence region. Recently, however, it is desirable to give an image of the image observed by the anti-glare film. In such a tendency, the unevenness formed on the outermost surface of the anti-glare film becomes natural, and even the anti-glare film has a poor state in which the interference fringes can be recognized.

[Invention]

The present invention has been made in view of the above problems, and an object of the present invention is to suppress interference fringes of a laminate by a method different from the prior art.

The first laminate of the present invention includes: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer, the opposite side of the optical substrate, the functional layer is laminated on the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the The average refractive index n _{3 in} the plane of the functional layer satisfies n ₁ < n ₂ < n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . The condition (a) and the condition (b) formed by the condition (b), the thickness t [nm] of the intermediate layer, the wavelength λ _ave between the shortest wavelength λ _min of visible light and the longest wavelength λ _max of visible light, And the average refractive index n _{2 in} the plane of the intermediate layer satisfies λ _ave / (6 × n ₂ ) < t < λ _ave / (3 × n ₂ ). . . Condition (c1) by condition (c1).

The second laminate of the present invention includes: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer, the opposite side of the optical substrate, the functional layer is laminated on the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the The average refractive index n _{3 in} the plane of the functional layer satisfies n ₁ < n ₂ < n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . In the condition (a) and the condition (b) which are formed by the condition (b), the thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 110/n ₂ ≦t ≦170/n ₂ . . . Condition (c2) formed by condition (c2).

The third laminate of the present invention includes: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer, the opposite side of the optical substrate, the functional layer is laminated on the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the The average refractive index n _{3 in} the plane of the functional layer satisfies n ₁ < n ₂ < n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . In the condition (a) and the condition (b) formed by the condition (b), the thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 555/(6 × n ₂ ) <t<555/(3×n ₂ ). . . Condition (c3) formed by condition (c3).

The fourth laminate of the present invention comprises: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer, the opposite side of the optical substrate, the functional layer is laminated on the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the The average refractive index n _{3 in} the plane of the functional layer satisfies n ₁ < n ₂ < n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . In the condition (a) and the condition (b) formed by the condition (b), the thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 507 / (6 × n) ₂ ) <t<507/(3×n ₂ ). . . Condition (c4) formed by condition (c4).

The fifth laminate of the present invention includes: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer, the opposite side of the optical substrate, the functional layer is laminated on the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and the The average refractive index n _{3 in} the plane of the functional layer satisfies n ₁ < n ₂ < n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . In the condition (a) and the condition (b) formed by the condition (b), the thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 555/(6 × n ₂ ) <t<507/(3×n ₂ ). . . Condition (c5) by condition (c5).

In any one of the first to fifth laminates of the present invention, the light-transmitting substrate has in-plane birefringence, and a direction of a maximum refractive index in an in-plane of the light-transmitting substrate, that is, in a slow axis direction a refractive index n _1x , a refractive index n _1y in a fast axis direction orthogonal to the slow axis direction of the light-transmitting substrate, an average refractive index n _{2 in a} plane of the intermediate layer, and a surface of the functional layer The average refractive index n _{3 within} can satisfy n _1x < n ₂ < n ₃ . . . Condition (d)

n _1y >n ₂ >n ₃ . . . Any of the conditions (d) and (e) formed by condition (e).

In any one of the first to fifth laminates of the present invention, the light-transmitting substrate has in-plane birefringence, and a direction of a maximum refractive index in an in-plane of the light-transmitting substrate, that is, in a slow axis direction a refractive index n _1x , a refractive index n _{2x of the} intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate, and a direction parallel to the slow axis direction of the light-transmitting substrate The refractive index n _{3x of the} aforementioned functional layer satisfies n _1x < n _2x < n _3x . . . Condition (f)

n _1x >n _2x >n _3x . . . Any one of the conditions (f) and (g) formed by the condition (g), the refractive index n _1y in the fast axis direction orthogonal to the slow axis direction of the light-transmitting substrate, and the light-transmitting group The refractive index n _{2y of the} intermediate layer in the direction parallel to the fast axis direction of the material and the refractive index n _{3y of the} functional layer in the direction parallel to the fast axis direction of the light transmitting substrate may satisfy n _1y <n _2y <n _3y . . . Condition (h)

n _1y >n _2y >n _3y . . . Condition (i) Any of the conditions (h) and (i).

In any one of the first to fifth laminates of the present invention, the intermediate layer has in-plane birefringence, and a refractive index n _{2x of the} intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate And a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate satisfies a relationship of n _2x >n _2y .

In any one of the first to fifth laminates of the present invention, the refractive index n _1x in the slow axis direction of the light-transmitting substrate, and the refractive index n _1y in the fast axis direction of the light-transmitting substrate, a refractive index n _{2x of the} intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate, and a refractive index of the intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate n _2y satisfies the relationship of (n _{1x -} n _1y ) > (n _{2x -} n _2y ).

In any one of the first to fifth laminates of the present invention, the intermediate layer has in-plane birefringence, and when the laminate is observed in a normal direction, the slow axis direction of the light-transmitting substrate and the intermediate layer The direction of the maximum refractive index in the plane, that is, the angle formed by the slow axis direction of the intermediate layer may be less than 30°.

In any one of the first to fifth laminates of the present invention, the intermediate layer has in-plane birefringence. The slow axis direction of the light-transmitting substrate may be parallel to the direction of the maximum refractive index in the plane of the intermediate layer, that is, the slow axis direction of the intermediate layer.

In any one of the first to fifth laminates of the present invention, the intermediate layer has in-plane birefringence, and a refractive index n _1x in the slow axis direction of the light-transmitting substrate and the light-transmitting substrate a refractive index n _1y in the fast axis direction, a direction of a maximum refractive index in an in-plane of the intermediate layer, that is, a refractive index n _2a in a slow axis direction of the intermediate layer, and the aforementioned slow axis direction of the intermediate layer The refractive index n _2b in the fast axis direction of the aforementioned intermediate layer may satisfy the relationship of (n _{1x -} n _1y ) > (n _{2a -} n _2b ).

A sixth laminate of the present invention, comprising: a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated on an intermediate layer of the light-transmitting substrate; and adjacent to the intermediate layer, the light-transmitting substrate the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . The condition (o) and the condition (p) formed by the condition (p), the thickness t [nm] of the intermediate layer, the longest wavelength λ _{max of} visible light, and the average refractive index n _{2 in} the plane of the intermediate layer Satisfy 0<t<λ _max /(12×n ₂ ). . . Condition (q1) formed by condition (q1).

A seventh laminate of the present invention, comprising: a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated on an intermediate layer of the light-transmitting substrate; and adjacent to the intermediate layer, the light-transmitting substrate the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . The condition (o) and the condition (p) formed by the condition (p), the thickness t [nm] of the intermediate layer, the shortest wavelength λ _min of visible light, the longest wavelength λ _{max of} visible light, and the surface of the intermediate layer The average refractive index n ₂ within the range satisfies 0 < t < ((λ _min + λ _max ) / 2) / (12 × n ₂ ). . . Condition (q2) formed by condition (q2).

An eighth laminate of the present invention, comprising: a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated on an intermediate layer of the light-transmitting substrate; and adjacent to the intermediate layer, the light-transmitting substrate the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . The condition (o) and the condition (p) formed by the condition (p), the thickness t [nm] of the intermediate layer, the shortest wavelength λ _min of visible light, the longest wavelength λ _{max of} visible light, and the surface of the intermediate layer The average refractive index n ₂ within the range satisfies 0 < t < λ _min / (12 × n ₂ ). . . Condition (q3) formed by condition (q3).

A ninth laminate of the present invention, comprising: a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated on an intermediate layer of the light-transmitting substrate; and adjacent to the intermediate layer, the light-transmitting substrate the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . The condition (o) and the condition (p) which are formed by the condition (p), the thickness t [nm] of the intermediate layer, and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 0 < t < 555 / (12×n ₂ ). . . Condition (q4) formed by condition (q4).

The tenth laminate of the present invention includes a light-transmitting substrate; an intermediate layer adjacent to the light-transmitting substrate and laminated on the light-transmitting substrate; and the light-transmitting substrate adjacent to the intermediate layer the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . The condition (o) and the condition (p) formed by the condition (p), the thickness t [nm] of the intermediate layer, and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 0 < t < 507 / (12×n ₂ ). . . Condition (q5) formed by condition (q5).

The eleventh laminate of the present invention comprises a light-transmitting substrate; an intermediate layer of the light-transmitting substrate adjacent to the light-transmitting substrate; and the light-transmitting substrate adjacent to the intermediate layer the opposite side of the substrate, the functional layer is laminated to the intermediate layer; average refractive index of the average refractive index of the transparent substrate surface of the n _1, the intermediate layer of the surface n _2, and the function The average refractive index n _{3 in} the plane of the layer satisfies n ₁ > n ₂ and n ₂ < n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . In either of the conditions (o) and (p) which are formed by the condition (p), the intermediate layer has a thickness of 3 nm or more and 30 nm or less.

In any one of the sixth to eleventh laminates of the present invention, the light-transmitting substrate has in-plane birefringence, and a direction of a maximum refractive index in an in-plane of the light-transmitting substrate, that is, in a slow axis direction a refractive index n _1x , a refractive index n _1y in a fast axis direction orthogonal to the slow axis direction of the light-transmitting substrate, an average refractive index n _{2 of the} intermediate layer, and an in-plane average of the functional layer The refractive index n ₃ can satisfy n _1y >n ₂ and n ₂ <n ₃ . . . Condition (r)

n _1x <n ₂ and n ₂ >n ₃ . . . Any of the conditions (r) and (s) formed by the condition (s).

In any one of the first to eleventh laminates of the present invention, the light-transmitting substrate has in-plane birefringence, and the retardation of the light-transmitting substrate may be 3,000 nm or more.

In any one of the first to eleventh laminates of the present invention, the light-transmitting substrate may be a polyester substrate.

In any one of the first to eleventh laminates of the present invention, the functional layer may be a hard coat layer.

In any one of the first to eleventh laminates of the present invention, a second functional layer provided on the opposite side of the intermediate layer side of the functional layer may be further provided.

In any one of the first to eleventh laminates of the present invention, the second functional layer may be a low refractive index layer having a refractive index lower than that of the functional layer.

The polarizing plate of the present invention includes a polarizing element and a laminate of any one of the first to eleventh aspects of the present invention.

The liquid crystal display panel of the present invention includes the laminate according to any one of the first to eleventh aspects of the present invention or the polarizing plate of the present invention.

The image display device of the present invention includes the laminate according to any one of the first to eleventh aspects of the present invention, the polarizing plate of the present invention, or the liquid crystal display panel of the present invention.

The touch panel sensor of the present invention includes the laminate according to any one of the first to eleventh aspects of the present invention, and a sensor electrode joined to the laminate.

The touch panel device of the present invention is provided with the touch panel sensor of the present invention.

The method for producing a first laminate of the present invention is a method for producing a laminate comprising a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated in the middle of the light-transmitting substrate a layer; a functional layer laminated on the opposite side of the light-transmitting substrate from the intermediate layer; and having one of the following conditions (a) and (b): the inner surface condition (c1) ~ (c5) of any of the above, setting the average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, the functional layers The step of the average refractive index n ₃ and the thickness t [nm] of the intermediate layer described above. λ _ave is the intermediate wavelength between the shortest wavelength λ _min of visible light and the longest wavelength λ _max of visible light.

n ₁ <n ₂ <n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . Condition (b)

λ _ave /(6×n ₂ )<t<λ _ave /(3×n ₂ ). . . Condition (c1)

110/n ₂ ≦t≦170/n ₂ . . . Condition (c2)

555/(6×n ₂ )<t<555/(3×n ₂ ). . . Condition (c3)

507/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c4)

555/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c5)

The design method of the first laminate of the present invention is a method of designing a laminate comprising a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated in the middle of the light-transmitting substrate a layer; a functional layer laminated on the opposite side of the light-transmitting substrate from the intermediate layer; and having one of the following conditions (a) and (b): the inner surface condition (c1) ~ (c5) of any of the above, setting the average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, the functional layers The step of the average refractive index n ₃ and the thickness t [nm] of the intermediate layer described above.

n ₁ <n ₂ <n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . Condition (b)

λ _ave /(6×n ₂ )<t<λ _ave /(3×n ₂ ). . . Condition (c1)

110/n ₂ ≦t≦170/n ₂ . . . Condition (c2)

555/(6×n ₂ )<t<555/(3×n ₂ ). . . Condition (c3)

507/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c4)

555/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c5)

The method for producing a second laminate of the present invention is a method for producing a laminate comprising a light-transmitting substrate, adjacent to the light-transmitting substrate, and laminated in the middle of the light-transmitting substrate a layer; a functional layer laminated on the opposite side of the light-transmitting substrate to the intermediate layer; and having one of the following conditions (o) and (p): condition (q1) ~ (q6) of the inner surface of any of the above functional layers, setting the average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, the The step of the average refractive index n ₃ and the thickness t [nm] of the intermediate layer described above. λ _min is the shortest wavelength of visible light, and λ _max is the longest wavelength of visible light.

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t<λ _max /(12×n ₂ ). . . Condition (q1)

0<t<((λ _min +λ _max )/2)/(12×n ₂ ). . . Condition (q2)

0<t<λ _min /(12×n ₂ ). . . Condition (q3)

0<t<555/(12×n ₂ ). . . Condition (q4)

0<t<507/(12×n ₂ ). . . Condition (q5)

3≦t≦30. . . Condition (q6)

The design method of the second laminate of the present invention is a method of designing a laminate comprising a light-transmitting substrate; adjacent to the light-transmitting substrate, laminated in the middle of the light-transmitting substrate a layer; a functional layer laminated on the opposite side of the light-transmitting substrate from the intermediate layer; and having one of the following conditions (o) and (p): condition (q1) ~ (q6) of the inner surface of any of the above functional layers, setting the average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, the The step of the average refractive index n ₃ and the thickness t [nm] of the intermediate layer described above. λ _min is the shortest wavelength of visible light, and λ _max is the longest wavelength of visible light.

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t<λ _max /(12×n ₂ ). . . Condition (q1)

0<t<((λ _min +λ _max )/2)/(12×n ₂ ). . . Condition (q2)

0<t<λ _min /(12×n ₂ ). . . Condition (q3)

0<t<555/(12×n ₂ ). . . Condition (q4)

0<t<507/(12×n ₂ ). . . Condition (q5)

3≦t≦30. . . Condition (q6)

According to the present invention, occurrence of interference fringes can be effectively suppressed.

10‧‧‧Layer

11‧‧‧Laminated substrate

12‧‧‧Transparent substrate

13‧‧‧Intermediate

15‧‧‧ functional layer

17‧‧‧2nd functional layer

Fig. 1 is a view for explaining 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 of another example of the laminate.

Fig. 3 is a view for explaining a waveform of light reflected in a laminate.

Fig. 4 is a view for explaining a refractive index distribution in the laminate shown in Fig. 1, and a perspective view showing the laminate in a mode.

Fig. 5 is a view for explaining the in-plane birefringence in the laminate shown in Fig. 1, schematically showing the flat substrate and the intermediate layer of the laminate. Surface map.

Fig. 6 is a schematic configuration view showing a polarizing plate including the laminate shown in Fig. 1 .

Fig. 7 is a schematic block diagram showing a liquid crystal display panel including the laminate shown in Fig. 1.

FIG. 8 is a schematic configuration diagram showing a display device including the laminate shown in FIG. 1. FIG.

FIG. 9 is a schematic block diagram showing a touch panel sensor and a touch panel including the laminate shown in FIG. 1. FIG.

Fig. 10 is a view corresponding to Fig. 3, and is a waveform diagram showing light reflected in the laminate of the second embodiment.

[Formation of the Invention] "First embodiment"

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In order to make the illustrations easy to understand, in order to facilitate the understanding of the drawings, the physical scale and the aspect ratio of the aspect ratio may be appropriately changed. Fig. 1 to Fig. 9 are views for explaining the first embodiment of the present invention. 1 and 2 are views for explaining a laminate. Figure 3 is a diagram illustrating the waveform of light reflected in a laminate. 4 and 5 are views for explaining the refractive index distribution of the laminate. 6 to 9 show patterns of a polarizing plate, a liquid crystal display panel, a touch panel sensor, a touch panel, and a laminate using the laminate of FIG. Figure.

Laminated body <The whole composition of the laminate>

First, the overall configuration of the laminate 10 will be described. As shown in FIG. 1, the laminate 10 has a laminated base material 11 and a functional layer 15 formed on one surface of the laminated base material 11. The laminated base material 11 has a light-transmitting substrate 12 and an intermediate layer 13 laminated with the light-transmitting substrate 12. In the laminate 10, the intermediate layer 13 is located between the light-transmitting substrate 12 and the functional layer 15. In other words, the functional layer 15 is laminated on the laminated substrate 11 from the intermediate layer 13 side. In the illustrated example, the intermediate 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 intermediate layer 13, and the functional layer 15, and the intermediate layer 13 is disposed adjacent to the light-transmitting substrate 12 and the functional layer 15, and is transparent. The interface between the substrate 12 and the functional layer 15 is formed.

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

The laminate 10 of the first embodiment preferably satisfies one of the following conditions (a) and (b), and at least satisfies the following condition (c1).

n ₁ <n ₂ <n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . Condition (b)

λ _ave /(6×n ₂ )<t<λ _ave /(3×n ₂ ). . . Condition (c1)

In the conditions (a) to (c1) and the conditions (c2) to (c5) described later, "n ₁ " is the average refractive index in the plane of the light-transmitting substrate 12, and "n ₂ " is the intermediate layer 13 The average refractive index in the plane, "n ₃ ", is the average refractive index in the plane of the functional layer 15. The average refractive index in the plane means an average value of refractive indices in two directions orthogonal to each other along the sheet surface of the sheet-like layer to be the object. When the target layer is optically isotropic, the refractive index in each direction along the sheet surface of the layer is the same. When the target layer is optically anisotropic, the refractive index in each direction along the sheet surface of the layer is different.

In addition, the "sheet surface (film surface, plate surface)" refers to a layer or a sheet-like layer (film-like, plate-shaped) which is a target, and when viewed from the whole and the large-scale, the sheet-like layer or The faces of the members that are in the same plane direction. In the laminate 10 described in the first embodiment, the sheet surface of the light-transmitting substrate 12, the sheet surface of the intermediate layer 13, the sheet surface of the functional layer 15, the sheet surface of the second functional layer 17, and the laminated substrate 11 The sheet faces and the sheet faces of the laminate 10 are parallel to each other.

Further, in the condition (c1), "λ _ave " is an intermediate wavelength [nm] between the shortest wavelength λ _min of visible light and the longest wavelength λ _max of visible light, which is shown below.

λ _ave =(λ _min +λ _max )/2

Further, in the condition (c1) and the conditions (c2) to (c5) to be described later, "t" is the thickness [nm] of the intermediate layer 13.

For the refractive index in each of the planes of the respective layers, the above-mentioned Abbe refractometer (NAR-4T manufactured by Adago Co., Ltd.), "Elliptical Thickness Gauge M150" manufactured by JASCO Corporation, and "KOBRA" manufactured by Oji Scientific Instruments Co., Ltd. can be used. -WR" or the like measures the refractive index.

In addition, the average reflectance (R) of the wavelength of 380 to 780 nm is measured by a spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation) in the refractive index of each of the layers in the plane, and the average reflectance (R) obtained is obtained. Use the following formula. The average reflectance (R) of the intermediate layer 13 and the functional layer 15 is applied to a PET having a thickness of 50 μm which is not easily treated, and a cured film having a thickness of 1 to 3 μm is formed, and the raw material of the uncoated PET is used. In order to prevent the inner surface reflection, the surface (inner surface) of the composition is adhered to a black vinyl tape (for example, yamato vinyl tape No. 200-38-21 38 mm width) which is wider than the spot area, and each coating can be measured. The average reflectance of the film. The refractive index of the light-transmitting substrate 12 is measured on the opposite side of the measurement surface, and is also attached to a black vinyl tape.

R(%)=(1-n) ² /(1+n) ²

Further, when the target layers 12, 13, and 15 are optically isotropic, the average refractive indices n ₁ , n ₂ , n _{3 in} the plane of the layer can be measured as follows. First, the cured film of each layer is cut out with a dicing blade or the like to prepare a sample (sampo) in a powder state. Next, a Becke method according to JIS K7142 (2008) B method (for powder or granular transparent material) can be used (the sample of the powder state is placed on a glass slide or the like using a Cargille reagent having a known refractive index, and the reagent is used. Dropping on the sample, impregnating the sample with a reagent. 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 refractive index of the reagent which cannot be visually observed , as a method of refractive index of the sample).

Further, the thickness (hardening time) t of the intermediate layer 13 is defined, for example, by the average value (nm) of the measured values of any 10 points obtained by observing the cross section of the intermediate layer 13 by an electron microscope (SEM, TEM, STEM). When the thickness of the intermediate layer 13 is very thin, the high-magnification observer records in a photograph and can be magnified and measured. When zoomed in, the layer interface line is clearly known to the interface line, and the very thin line becomes a thick line. At this time, the center line portion in which the thick line width is divided into two equal parts in the width direction may be measured as an interface line.

When the laminate 10 satisfies the condition (c1) and satisfies at least one of the conditions (a) and (b), the interference fringe in the laminate 10 can be effectively suppressed. Here, the interference fringes to be invisible are from the functional layer 15 side, to the light of the laminated body 10 of FIG. 1, the reflected light on the surface of the functional layer 15 and the reflected light by the laminated substrate 11 The interference fringes produced by the interference of (light L _{r of} Fig. 3). Similarly, from the second functional layer 17 side to the light of the laminate 10 of FIG. 2, the reflected light on the surface of the second functional layer 17 or the reflected light at the interface between the second functional layer 17 and the functional layer 15 is the interference light reflected by the laminated base material (FIG. 3 of the light L _r) 11 of the interference fringes generated object has become invisible interference fringes. Therefore, the reflected light (light L _{r of} FIG. 3) by the laminated substrate 11 means the reflected light at the interface between the functional layer 15 and the intermediate layer 13 (light L _{r1 of} FIG. 3) and the intermediate layer 13 and light transmittance. The reflected light at the interface of the substrate 12 (light L _{r2 of} Fig. 3).

In the following, the fringe invisibility function exhibited by the laminate 10 satisfying the condition (c1) while satisfying one of the conditions (a) and (b), in other words, suppressing the occurrence of interference fringes, that is, suppressing, can be visually confirmed. The function of the interference fringe, and further, the function of making the interference fringes inconspicuous.

First, the intermediate layer 13 is provided between the light-transmitting substrate 12 and the functional layer 15, and the refractive index is between the light-transmitting substrate 12 and the functional layer 15 because one of the conditions (a) and (b) is satisfied. Gradually change. In other words, the intermediate layer 13 is provided between the light-transmitting substrate 12 and the functional layer 15, and the average refractive index in the plane is divided into two stages between the light-transmitting substrate 12 and the functional layer 15. Therefore, between the functional layer 15 and the light-transmitting substrate 12, there is no interface in which the average refractive index in the plane largely changes. In other words, between the functional layer 15 and the light-transmitting substrate 12, there is only an interface in which the difference in average refractive index in the plane is small, and thus the reflectance is lowered.

Therefore, the light (light L _{i of} FIG. 3) incident on the laminated body 10 from the functional layer 15 side advances between the light-transmitting substrate 12, and it is possible to effectively prevent the direction from being reversed by the reflection. Thereby, the light from the side of the functional layer 15 can be incident on the surface of the laminated body 10, and the light reflected on the surface of the functional layer 15 side of the laminated body 10 and the reflected light by the laminated base material 11 can be effectively produced. The interference fringes become less noticeable.

Further, when one of the conditions (a) and (b) is satisfied while satisfying the condition (c1), the reflectance can be lowered. As will be described later in detail, the inside of the laminate 10 can be effectively reduced from the functional layer 15 side to the lamination. side of the substrate 11, the substrate 11 in the laminating side of the reflection returning light function layer 15 (FIG. 3 light L _r) intensity. In other words, by reducing the intensity of the light that causes the interference fringes, the interference fringes can be effectively made inconspicuous.

A method of making the interference fringes generated by the laminate invisible, for example, a method of blurring the interface in the laminate by providing a mixed existence region and a method of forming irregularities on the surface of the laminate. However, as described above, in the method of providing the mixed existence region, in order to secure the strength of the laminate 10, it is necessary to increase the thickness of the functional layer. Therefore, when this method is employed, the material cost is increased, and an unsatisfactory state in which the manufacturing cost of the laminate 10 rises is caused. Moreover, when the method of forming the unevenness on the surface of the laminated body 10 is used, the image quality of the image observed by the laminated body 10 deteriorates. Specifically, the screen produces a white turbidity, reduces contrast, and the gloss or brilliance of the image disappears.

On the other hand, the laminate 10 satisfying the condition (a) and the condition (b) while satisfying the condition (c1) does not need to have a mixed existence region and does not need to increase the thickness of the functional layer. Further, when the intermediate layer 13 is used as an example, for example, by a primer layer such as an easy-adhesion layer, it is not necessary to provide an additional layer in the laminate 10 for the purpose of the interference stripe countermeasure, and the cost side is not generated. The shortcomings. Further, a polyester base material which is difficult to mix the existing region itself can be provided, and can be used as the light-transmitting substrate 12. The light-transmitting substrate 12 composed of a polyester base material is excellent in cost, stability, and the like.

In addition, one of condition (a) and condition (b) is satisfied, At the same time, the laminate 10 satisfying the condition (c1) does not need to cause diffusion, so that the surface is kept smooth and the occurrence of interference fringes can be effectively prevented. Therefore, the image quality of the image observed by the laminate 10 is not adversely affected, and the interference fringes can be made invisible. In other words, the laminate 10 satisfying the condition (c1) and satisfying the condition (c1) imparts luster and brilliance to the display image and prevents the occurrence of white turbidity and interference fringes.

Here, with reference to FIG. 3, by satisfying one of the conditions (a) and (b), the laminate 10 satisfying the condition (c1) exhibits a decrease in the light intensity of the reflected light from the laminated substrate 11. Features.

When one of the conditions (a) and (b) is satisfied, the light incident on the laminated body 10 from the side of the functional layer 15 is at the interface between the functional layer 15 and the intermediate layer 13 and the interface between the intermediate layer 13 and the light-transmitting substrate 12. On both sides, the phase is deviated by π[rad] with fixed-end reflection, or at both ends of the interface, the free-end reflection maintains the phase. The laminate 10 shown in FIG. 3 satisfies the condition (b) in the condition (a) and the condition (b), and the light incident on the laminate 10 from the functional layer 15 side, and the functional layer 15 and the intermediate layer 13 Both the interface and the interface between the intermediate layer 13 and the light-transmitting substrate 12 are reflected at the fixed end to shift the phase by π [rad].

As shown in the example of FIG. 3, the cross section along the normal direction nd of the laminated body 10 is shown. 3 shows the incident light L _i incident on the laminate 10 from the functional layer 15 side, the reflected light L _r1 reflected at the interface between the functional layer 15 and the intermediate layer 13 , and the intermediate layer 13 and the light-transmitting substrate 12 . The reflected light L _r2 reflected by the interface and the combined reflected light L _r synthesized by the reflected light L _r1 and the reflected L _{r2 are} in a vibrating state at a certain moment. As shown in FIG. 3, the x-axis extends in the normal direction of the laminate 10, and the y-axis extends at the interface between the functional layer 15 and the intermediate layer 13, so that when the xy coordinates are set, the respective lights L _i , L _r1 , L _r2 , The waveforms of L _r are represented by the following equations (1) to (4). In the following formulas (1) to (4), "λ" is the wavelength [nm] of light.

Y _i =sin((x×n ₃ /λ)×2π). . . Formula 1)

Y _r1 =sin((x×n ₃ /λ)×2π). . . Formula (2)

Y _r2 = sin(((x×n ₃ /λ)+(2t×n ₂ /λ))×2π). . . Formula (3)

Y _r = 2. Cos(2t×n ₂ ×π/λ). Sin(((x×n ₃ /λ)+(t×n ₂ /λ))×2π). . . Formula (4)

In other words, the intensity of the combined reflected light L _r of the laminated base material 11 that causes the interference fringes is expressed by "2.cos (2t.n ₂ .π/λ)" indicating the amplitude of the waveform of the light. The weaker the intensity of the interference fringe-synthesized reflected light L _r , the less noticeable it becomes. Therefore, when the following equation (5) is satisfied that the amplitude of the synthesized reflected light L _r is less than one-half of the maximum value ("2") (not "1"), the interference fringes caused by the light of the wavelength λ are not conspicuous. The viewpoint is a preferable condition, and when the equation (6) is satisfied when the amplitude exceeds one-half of the maximum value, the interference fringe caused by the light of the wavelength λ is not conspicuous, which is a poor condition.

λ/(6×n ₂ )<t<λ/(3×n ₂ ). . . Formula (5)

t<λ/(6×n ₂ ) or λ/(3×n ₂ )<t. . . Formula (6)

As described above, when the condition (b) and the condition (c1) are satisfied, it is possible to effectively prevent the light containing the center wavelength of visible light, that is, the wavelength region of the wavelength λ _ave from being recognized by the interference fringes. In other words, the light having at least the wavelength region of the visible light center wavelength λ _ave can effectively make the interference fringes invisible.

Further, in the replacement condition (b), when the condition (a) and the condition (c1) are satisfied, the interference fringe can be effectively made invisible to the light including the visible light wavelength region of at least a part of the visible light center wavelength λ _ave . . When the condition (a) is satisfied, the light incident on the laminated body 10 from the functional layer 15 side is at the interface between the intermediate layer 13 and the light-transmitting substrate 12 and the interface between the functional layer 15 and the intermediate layer 13, and the free end is reflected. Maintain the phase. Therefore, with respect to the incident light Li of FIG. 3, only the light of the phase retardation of π [rad] is incident on the laminated body 10 satisfying the condition (a) and the condition (c1) from the functional layer 15 side, and the reflection of the laminated substrate 11 is performed. The light exhibits the same waveform of the reflected light L _r1 , L _r2 , L _r as shown in FIG. 3 . From this point of view, even when the condition (a) and the condition (c1) are satisfied instead of the condition (b), the interference fringes can be effectively made invisible for at least a part of the visible light.

Further, in the replacement condition (b), when the condition (a) is satisfied, the intermediate layer 13 is provided between the light-transmitting substrate 12 and the functional layer 15 in the same manner as in the case of satisfying the condition (b), in the light-transmitting substrate. Between 12 and the functional layer 15, the average refractive index in the plane is divided into two stages. Therefore, by effectively reducing the reflectance, the light incident on the laminated body 10 from the functional layer 15 side advances between the light-transmitting substrates 12, and it is possible to effectively prevent the direction from being reversed by the reflection. Thereby, the light from the side of the functional layer 15 can be incident on the surface of the laminated body 10, and the light reflected on the surface of the functional layer 15 side of the laminated body 10 and the reflected light by the laminated base material 11 can be effectively produced. The interference fringes become less noticeable.

As described above, when one of the above conditions (a) and (b) and the condition (c1) are satisfied, it is possible to effectively prevent light including a visible light wavelength region of at least a part of the visible light center wavelength λ _ave from being recognized by the interference fringes. In other words, when one of the conditions (a) and (b) and the condition (c1) are satisfied, the interference fringe is not visible to the light having the wavelength region of the visible light center wavelength λ _ave (the interference fringes are not noticeable). Features). Furthermore, when one of the above conditions (a) and (b) and the condition (c1) are satisfied, the light in the visible light wavelength region containing the visible light center wavelength λ _ave affects the interference fringe invisibility function, and therefore is very Effectively make the interference fringes less noticeable.

Further, according to the definition of JIS Z8120, the longest wavelength λ _max in the visible light wavelength region is 830 nm, and the shortest wavelength λ _{min in the} visible light wavelength region may be 360 nm.

In addition, when the inventors of the present invention have carefully obtained the results and satisfied one of the above conditions (a) and (b), and satisfy the following condition (c2), the interference fringes can be recognized very effectively even if they are observed with great care. .

n ₁ >n ₂ >n ₃ . . . Condition (a)

n ₁ <n ₂ <n ₃ . . . Condition (b)

110/n ₂ ≦t≦170/n ₂ . . . Condition (c2)

Further, from the viewpoint of not obscuring the interference fringes, one of the above conditions (a) and (b) is satisfied, and the following condition (c3) or condition (c4) is satisfied, and the condition (c5) is satisfied, and the interference is effectively made. The stripes are not visible.

n ₁ <n ₂ <n ₃ . . . Condition (a)

n ₁ >n ₂ >n ₃ . . . Condition (b)

555/(6×n ₂ )<t<555/(3×n ₂ ). . . Condition (c3)

507/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c4)

555/(6×n ₂ )<t<507/(3×n ₂ ). . . Condition (c5)

The International Commission on Illumination (CIE) reports that people's sensitivities are different for light in each wavelength region in the visible region. According to the International Commission on Illumination (CIE), the light wavelength that people can easily feel is 555 nm when they are in a bright place. When they are in a dark place, the light wavelength that people can easily feel is 507 nm. Therefore, when one of the conditions (a) and (b) and the condition (c3) are satisfied, the light in the wavelength region which is most easily perceived by the human being in the bright portion can effectively exhibit the interference fringe invisibility function. In other words, when one of the conditions (a) and (b) and the condition (c3) are satisfied, interference fringes which can be recognized in a bright place can be effectively prevented. Further, when one of the conditions (a) and (b) and the condition (c4) are satisfied, the light in the wavelength region which is most easily perceived by the human being in the dark portion can effectively exhibit the interference fringe invisibility function. In other words, when one of the conditions (a) and (b) and the condition (c4) are satisfied, the interference fringes which can be recognized in the dark can be effectively prevented. Further, when one of the conditions (a) and (b) and the condition (c5) are satisfied, not only the light in the wavelength region which is most easily perceived by the human being in the bright portion but also the light in the wavelength region which is most easily perceived by the human being in the dark portion It can effectively exert the function of invisibility of interference fringes. In other words, when one of the conditions (a) and (b) and the condition (c5) are satisfied, the interference fringes can be effectively prevented from being recognized in a bright place or a dark place.

Further, not only the above formula (5) but also the expression (5') below the natural number k is used, and the interference fringes caused by the light of the wavelength λ are not made conspicuous, and it is also excellent. When the formula (5') is satisfied, only the optical path of the reflected light L _r2 becomes longer (λ × k) / (2 × n ₂ ) [nm] than the case where the formula (5) is satisfied, and the synthesized reflected light L _r The waveform has not changed. Therefore, the same effect can be expected in the case where the formula (5') is satisfied and the case where the formula (5) is satisfied.

λ / (6 × n ₂ ) < t - (k × λ) / (2 × n ₂ ) < λ / (3 × n ₂ ). . . Formula (5')

Therefore, when one of the conditions (a) and (b) and the condition (c1') are satisfied, the same effect can be expected when one of the conditions (a) and (b) and the condition (c1) are satisfied.

λ _ave /(6×n ₂ )<t-(k×λ _ave )/(2×n ₂ )<λ _ave /(3×n ₂ ). . . Formula (c1')

In addition, for the same conditions (c2) to (c4), in place of the above conditions (c2) to (c5), when the following conditions (c2') to (c5') are satisfied, the following conditions are satisfied. When the condition (c2) to the condition (c5), the same effect can be expected.

110/n ₂ ≦t-(k×λ _ave )/(2×n ₂ )≦170/n ₂ . . . Condition (c2')

555/(6×n ₂ )<t-(k×555)/(2×n ₂ )<555/(3×n ₂ ). . . Condition (c3')

507/(6×n ₂ )<t-(k×507)/(2×n ₂ )<507/(3×n ₂ ). . . Condition (c4')

507/(6×n ₂ )<t-(k×((507+555)/2))/(2×n ₂ )<507/(3×n ₂ ). . . Condition (c5')

However, the substitution condition (c1) to condition (c5) satisfying the condition (c1') to the condition (c5') means that the thickness t [nm] of the intermediate layer 13 is increased. Therefore, from the viewpoint of the material cost, it is preferable to satisfy the condition (c1) to the condition (c5) when the condition (c1') to the condition (c5') are satisfied.

However, the prior art column has also been described. Recently, the light-transmitting substrate 12 may have in-plane birefringence. When the light-transmitting substrate 12 has an in-plane birefringence, the refractive index changes in each of the directions along the plane of the sheet surface of the light-transmitting substrate 12. In addition, in order to effectively exhibit the function of reducing the intensity of the synthetic interference light L _r , the average refractive index n _{1 in} the plane of the light-transmitting substrate 12 satisfies not only one of the above formulas (a) and (b), but also It is preferable to satisfy one of the following conditions (d) and (e).

n _1x <n ₂ <n ₃ . . . Condition (d)

n _1y >n ₂ >n ₃ . . . Condition (e)

Here, "n _1x " in the condition (e) is a value of the maximum refractive index direction in the in-plane of the light-transmitting substrate 12, that is, the refractive index in the slow axis direction. _Further , "n _1y " in the condition (d) is the direction of the minimum refractive index in the plane of the light-transmitting substrate 12, that is, the value of the refractive index in the fast axis direction.

When one of the formula (d) and the formula (e) is satisfied, not only the average refractive index n ₁ in the plane of the light-transmitting substrate 12 but also the refractive index n in all directions in the plane of the light-transmitting substrate 12 _Arb satisfies one of the following conditions (d') and condition (e').

n _arb <n ₂ <n ₃ . . . Condition (d')

n _arb >n ₂ >n ₃ . . . Condition (e')

When one of the condition (d') and the condition (e') is satisfied, the slow axis direction in the plane of the light-transmitting substrate 12 generates the light of the polarized component of the vibration and the fast axis in the plane of the light-transmitting substrate 12. The direction, the light that generates the polarization component of the vibration, with respect to the phase deviation, causes reflection at the interface between the functional layer 15 and the intermediate layer 13 under the same conditions, and with respect to the phase deviation, the intermediate layer 13 and the same condition are mutually The interface of the optical substrate 12 produces a reflection. In other words, when one of the condition (d') and the condition (e') is satisfied, the light in the laminated body 10 from the side of the functional layer 15 toward the side of the laminated substrate 11 does not depend on the polarized state of the light, but is in the functional layer. The interface between the interface with the intermediate layer 13 and the interface between the intermediate layer 13 and the transparent substrate 12 is either free-end reflective or fixed-end reflection at both interfaces. Therefore, when one of the condition (d') and the condition (e') is satisfied, the amount of light (the reflectance of the laminated substrate 11) for reflecting light by the laminated base material 11 can be exhibited very effectively without depending on the polarized state. The reduced function and the function of reducing the intensity of the synthetic interference light L _r .

However, when one of the conditions (a) and (b) is satisfied, but the condition (d') and the condition (e') are not simultaneously satisfied, the laminate is moved from the functional layer 15 side toward the laminated substrate 11 side. A portion of the light within 10 depends on the polarization state of the light, and the free end reflection is performed at the interface between the functional layer 15 and the intermediate layer 13 and at the interface between the intermediate layer 13 and the transparent substrate 12 At the other interface, the fixed end reflection is performed. With such a light, the function of the intensity of the synthetic interference light L _r described above cannot be effectively reduced, and the function of the amount of light reflected by the laminated base material 11 (reflectance of the laminated base material 11) cannot be effectively reduced. However, when one of the conditions (a) and (b) is satisfied, the condition (d') and the condition (e') are not satisfied, and the layer is traveled toward the side of the laminated substrate 11 from the functional layer 15 side. More light in the body 10 can effectively exhibit the function of making the interference fringes invisible. In other words, when one of the conditions (a) and (b) is satisfied and any of the above conditions (c1) to (c6) is satisfied, the light incident on the laminated body 10 from the side of the functional layer 15 is mainly exerted. The function of reducing the amount of light reflected by the laminated base material 11 (the reflectance of the laminated base material 11) and the function of reducing the intensity of the synthetic interference light L _r can effectively make the interference fringes inconspicuous.

Further, when the light-transmitting substrate 12 has an in-plane birefringence, the refractive indices n _1x , n _2x , n _3x , n of the respective directions d _x , d _y of the respective layers 12, 13, 15 as shown in FIG. _1y , n _2y , n _3y , preferably set as described below. In other words, the maximum refractive index direction in the in-plane of the light-transmitting substrate 12 is obtained from the viewpoint of effectively reducing the amount of light reflected by the laminated substrate 11 (the reflectance of the laminated substrate 11). , i.e., a slow axis direction in the d _x refractive index n _1x, the refractive index of the intermediate layer in a direction parallel to the _x n _2x d and the slow axis direction of the transparent substrate 12, and the transparent substrate and the slow axis 12 of the The refractive index n _3x of the functional layer 15 in the direction d _x parallel direction satisfies n _1x < n _2x < n _3x . . . Condition (f)

n _1x >n _2x >n _3x . . . The condition (f) and (g) of the condition (g) is a refractive index n in the fast axis direction d _y orthogonal to the slow axis direction d _x in the plane of the light-transmitting substrate 12 _1y , the refractive index n _2y of the intermediate layer 13 in the direction parallel to the fast axis direction d _{y of the} light-transmitting substrate 11 , and the functional layer 15 in a direction parallel to the fast axis direction d _{y of the} light-transmitting substrate 12 The refractive index n _3y satisfies n _1y <n _2y <n _3y . . . Condition (h)

n _1y >n _2y >n _3y . . . Any of the conditions (h) and (i) formed by the condition (i) is preferred.

When either of the conditions (f) and (g) is satisfied and any of the conditions (h) and (i) is satisfied, the intermediate layer 13 is disposed on the functional layer 15 and a light-transmitting group having birefringence. between the material 12, the transparent substrate 12 of the slow axis direction and a fast axis direction _X d d _y of the two directions, the refractive index change is divided into two stages. Thereby, between the functional layer 15 and the translucent substrate 12 having birefringence, there is no interface in which the refractive index in the slow axis direction d _x of the light-transmitting substrate 12 largely changes, and there is no light transmission. The interface in which the refractive index in the fast axis direction d _y of the substrate 12 changes greatly. In other words, between the functional layer 15 and the translucent substrate 12 having birefringence, the difference in refractive index between the slow axis direction d _x and the fast axis direction d _y of the light-transmitting substrate 12 is small, and therefore only There is an interface where the reflectance is lowered.

Therefore, it is possible to effectively prevent light incident on the laminated body 10 from the side of the functional layer 15 and to cause the direction to be folded back due to reflection between the traveling toward the light-transmitting substrate 12. Thereby, the light reflected by the surface of the functional layer 15 and the interface between the functional layer 15 and the intermediate layer 13 or the intermediate layer 13 and the light transmissivity can be effectively made to be incident on the light of the laminated body 10 from the functional layer 15 side. The light reflected by the interface of the substrate 12 is not conspicuous.

Further, the refractive index n _2x of the intermediate layer 13 in the direction parallel to the slow axis direction d _x of the light-transmitting substrate 12 and the intermediate layer 13 in the direction parallel to the fast axis direction d _{y of the} light-transmitting substrate 12 The refractive index n _2y satisfies n _2x >n _2y . . . The condition (j) formed by the condition (j) is preferred. At this time, the intermediate layer 13 also has in-plane birefringence. When the condition (j) is satisfied, between the functional layer 15 and the light-transmitting substrate 12 having birefringence, the refractive index in the slow axis direction d _x of the light-transmitting substrate 12 can be divided into two, each time a little change And the refractive index in the fast axis direction d _y of the light-transmitting substrate 12 can also be divided into two, each time a little change. Thereby, the light incident on the laminated body 10 from the functional layer 15 side can be more effectively prevented from traveling between the light-transmitting substrates 12, and the direction is reversed due to the reflection. As a result, the interference fringes can be made more effective.

Further, when the condition (j) is satisfied, the refractive index n _1x in the slow axis direction d _x of the light-transmitting substrate 12, the refractive index n _1y in the fast axis direction d _y of the light-transmitting substrate 12, and the light transmission The refractive index n _2x of the intermediate layer 13 in the slow axis direction d _x parallel direction of the substrate 12 and the refractive index n _2y of the intermediate layer 13 in the direction parallel to the fast axis direction d _{y of the} light-transmitting substrate 12 satisfy (n _1x -n _1y )>(n _2x -n _2y ). . . The condition (k) formed by the condition (k) is better. For example, the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction d _x of the light-transmitting substrate 12 and the refractive index of the functional layer 15 in the direction parallel to the fast axis direction d _{y of the} light-transmitting substrate 12 When the rate n _{3y is} not greatly different, the functional layer 15 is typically optically isotropic. When the birefringence is not present, the intermediate layer 13 does not exhibit a strong double or more because the condition (j) and the condition (k) are satisfied. The refractive index is changed in two directions in the slow axis direction d _x and the fast axis direction d _y of the light-transmitting substrate 12 in a small amount. Thereby, the light incident on the laminated body 10 from the functional layer 15 side can be more effectively prevented from traveling between the light-transmitting substrates 12, and the direction is reversed due to the reflection. As a result, the interference fringes can be made more effective.

Further, as shown in FIG. 5, when the layered base 11 by the normal direction (laminated direction normal to the substrate 11 of the one-sided sheet) was observed, the slow axis of the transparent substrate 12 and the intermediate layer 13 d _x The direction of the maximum refractive index in the plane, that is, the angle θ formed by the slow axis direction d _{a of} the intermediate layer 13 is preferably less than 45° (condition (1a)), more preferably less than 30. ° (condition (1b)). The smaller the angle θ, the smaller the distribution of the refractive index in the plane of the intermediate layer 13 and the smaller the distribution of the refractive index in the plane of the light-transmitting substrate 12.

In other words, when the condition (1a) is satisfied, when the angle θ is less than 45°, not only the two directions of the slow axis direction d _x and the fast axis direction d _y of the light-transmitting substrate 12 but also along the light-transmitting substrate 12 are obtained. The refractive index in various directions of the sheet surface is not changed greatly between the functional layer 15 and the light-transmitting substrate 12, and can be divided into two gradual changes, which is a preferable condition. Further, when the condition (1b) is satisfied, when the angle θ is less than 30°, not only the two directions of the slow axis direction d _x and the fast axis direction d _y of the light-transmitting substrate 12 but also along the light-transmitting substrate 12 are obtained. The refractive index in the approximate direction of the sheet surface does not vary greatly between the functional layer 15 and the light-transmitting substrate 12, and can be divided into two gradual changes. In particular, when the angle θ is 0°, in other words, when the slow axis direction d _{x of the} light-transmitting substrate 12 is parallel to the slow axis direction d _{a of the} intermediate layer 13 (condition (m)), the refractive index in each direction is exhibited. The change in the refractive index in the different directions is the same, 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 can be more effectively prevented from traveling between the light-transmitting substrates 12, and it is very effective to prevent the interference fringes from being remarked by the reflection.

Here, the ellipse shown on the light-transmitting substrate 12 in FIG. 5 indicates the refractive index ellipse showing the refractive index distribution of the light-transmitting substrate 12. A cross section on the light-transmitting substrate 12 of one of the round bodies. Similarly, the ellipse depicted on the intermediate layer 13 in Fig. 5 represents a cross section on the intermediate layer 13 which is an example of a refractive index ellipsoid showing the refractive index distribution of the intermediate layer 13.

Further, the refractive index n _1x in the slow axis direction d _x of the light-transmitting substrate 12, the refractive index n _1y in the fast axis direction d _y of the light-transmitting substrate 13 , and the slow axis direction d _a of the intermediate layer 13 The refractive index n _2a and the refractive index n _2b in the fast axis direction d _b of the intermediate layer satisfy (n _1x -n _1y )>(n _2a -n _2b ). . . The condition (n) formed by the condition (n) is preferred. When the condition (n) is satisfied, as in the case where the above condition (k) is satisfied, the intermediate layer 13 can be prevented from having a strong birefringence or more, whereby the interference fringes can be effectively made inconspicuous.

<Light-transmitting substrate>

The light-transmitting substrate 12 will be described in detail below. There is no particular limitation as long as it has light transmissivity, such as a CELLULOSE ACYLATE substrate, a cycloolefin polymer substrate, a polycarbonate substrate, an acrylate polymer substrate, a polyester substrate, or Glass substrate.

The deuterated cellulose substrate is, for example, a cellulose triacetate substrate or a cellulose diacetate substrate. The cycloolefin polymer substrate is, for example, a substrate made of a polymer such as a norbornene-based monomer or a monocyclic cycloolefin monomer.

The cycloolefin polymer substrate is, for example, a substrate made of a polymer such as a norbornene-based monomer or a monocyclic cycloolefin monomer.

The polycarbonate substrate is, for example, an aromatic polycarbonate substrate based on bisphenols (bisphenol A or the like), diethylene glycol bisallyl carbonate. An aliphatic polycarbonate substrate or the like.

Acrylate-based polymer substrate, for example, a poly(methyl) methacrylate substrate, a poly(ethyl) acrylate substrate, a methyl (meth) acrylate-butyl (meth) acrylate copolymer base Materials and so on.

The polyester substrate is, for example, polyethylene terephthalate, polytrimethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly(1,4-stretch) At least one of cyclohexylene dimethylene terephthalate, polyethylene naphthalate, and polyethylene-2,6-naphthoate is a base material of a constituent component.

The glass substrate is, for example, a glass substrate such as soda lime cerium oxide glass, borosilicate glass or alkali-free glass.

The average refractive index n _{1 in} the plane of the light-transmitting substrate 12 can be 1.40 or more and 1.80 or less.

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.

However, the light-transmitting substrate 12 may have an in-plane birefringence. The light-transmitting substrate 12 having the in-plane birefringence is generally excellent in stability in terms of mechanical properties, transparency, heat, etc., and is cost-effective. Often beneficial. The light-transmitting substrate 12 having in-plane birefringence will be described below.

The optically anisotropic light-transmitting substrate 12 is advantageous in terms of physical properties and cost, but the optically anisotropic light-transmitting substrate 12 is superposed on the light-forming image of one of the linearly polarized components. When a display device of a liquid crystal display panel is used, a spot pattern called a rainbow spot is sometimes observed to occur. In order to solve the problem of this rainbow spot, the light-transmitting substrate 12 has a retardation of 3000 nm or more. When the light-transmitting substrate having a retardation of 3000 nm or more is used, even if the light-transmitting substrate is incorporated in an image display device, rainbow spots can be effectively suppressed from occurring in the display image of the image display device. The mechanism by which the rainbow spots are not visible is still unclear, but when a high retardation is imparted to the light-transmitting substrate 12, the light that generates the rainbow spots becomes a more continuous spectral distribution, whereby the material has become unrecognizable and presents a special Color spots.

In addition, the light-transparent base material 12 having such a high retardation has an optically equivalent base material such as a base material made of triethylenesulfonated cellulose which has been widely used in the past, and has the following effects. When an optically isotropic substrate is superposed on a display device such as a liquid crystal display panel that forms an image by light of one of the linearly polarized components, an observer who wears polarized glasses represented by the sunglasses depends on the polarized light. The absorption axis of the glasses is deflected, and the image of the image display device cannot be observed brightly. Further, the image of the image display device cannot be observed to be unsatisfactory. On the other hand, when the optically anisotropic transparent substrate 12 is used, particularly when the light-transmissive substrate 12 having a high retardation of 3000 nm or more is used, it is not inferior to the case of using an optically isotropic substrate. The deflection of the absorption axis of the polarized glasses allows the image to be observed more brightly. This phenomenon is presumed to be a polarization state of the image light projected by the display device, and is caused by the optically anisotropic light-transmitting substrate 12, particularly the highly retarded light-transmitting substrate 12 of 3000 nm or more. of. Recently, the use environment of display devices has been rapidly diversified, for example, widely used in mobile devices or devices used outdoors. With the diversification of the use of such a display device, the state in which the observer observes the display device is more frequently generated in the state in which the observer wears the polarized glasses. Due to this tendency, the optically anisotropic light-transmitting substrate 12, particularly the light-transmissive substrate 12 having a high retardation of 3,000 nm or more, is very suitable for the optical film 10.

The delay is an indicator of the degree of birefringence in the plane. From the viewpoints of rainbow spot prevention and film formation, it is preferably 6000 nm or more and 25,000 nm or less, more preferably 8000 nm or more and 20,000 nm or less.

The retardation Re (unit: nm) is a refractive index (n _1x ) in the direction of the maximum refractive index (slow axis direction) in the plane of the light-transmitting substrate, and a direction orthogonal to the slow axis direction (fast axis direction). The refractive index (n _1y ) and the thickness d (unit: nm) of the light-transmitting substrate are represented by the following formula (7).

Re=(n _1x -n _1y )×d. . . (7)

For the delay, for example, KOBRA-WR manufactured by Prince Measurement Co., Ltd. can be used, and the value measured by the measurement angle of 0° and the measurement wavelength of 548.2 nm can be set. The delay can also be obtained by the following method. First, using two polarizing plates, the direction of the alignment axis of the light-transmitting substrate was obtained, and the refractive index of the two axes orthogonal to the direction of the alignment axis was obtained by an Abbe refractometer (NAR-4T manufactured by ATAGO Co., Ltd.). Rate (n _1x , n _1y ). Here, the axis showing the larger refractive index is defined as the slow axis. Moreover, the thickness of the light-transmitting substrate is measured using, for example, an electric micrometer (manufactured by Anritsu Co., Ltd.). Further, using the obtained refractive index, the refractive index difference (n _{1x -} n _1y ) (hereinafter, n _{1x -} n _{1y is} referred to as Δn), and the refractive index difference Δn and the thickness d of the light-transmitting substrate are calculated. The product of (nm) is delayed.

The difference between the refractive index n _{1x in} the slow axis direction of the light-transmitting substrate 12 and the refractive index n _{1y in} the fast axis direction from the viewpoint of the retardation of the light-transmitting substrate 12 being 3,000 nm or more (hereinafter also referred to as "refractive index" The difference Δn") is preferably 0.05 to 0.20. When the refractive index difference Δn is less than 0.05, the thickness required to obtain the above retardation value becomes thick. On the other hand, when the refractive index difference Δn exceeds 0.20, the light-transmitting substrate 12 is liable to be broken or broken, 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 in the moist heat resistance test may be inferior depending on the type of the light-transmitting substrate 12 . From the viewpoint of ensuring excellent durability against the moist heat resistance test, the upper limit of the above refractive index difference Δn is preferably 0.12.

Further, the refractive index n _1x in the slow axis direction d _x of the light-transmitting substrate 12 is preferably 1.60 to 1.80, more preferably 1.65, and even more preferably 1.75. Further, the refractive index n _1y in the fast axis direction d _y of the light-transmitting substrate 12 is preferably 1.50 to 1.70, more preferably 1.55, and even more preferably 1.65. When the refractive index n _1x in the slow axis direction d _x of the light-transmitting substrate 12 and the refractive index n _1y in the fast axis direction d _y are within the above range, and the relationship of the above refractive index difference Δn is satisfied, more The suppression effect of the best rainbow spots.

The thickness of the light-transmitting substrate 12 having in-plane birefringence is not particularly limited, and may be usually 5 μm or more and 1000 μm or less, and the lower limit of the thickness of the light-transmitting substrate 12 is preferable from the viewpoint of workability and the like. It is 15 μm or more, and more preferably 25 μm or more. The upper limit of the thickness of the light-transmitting substrate 12 is preferably 80 μm or less from the viewpoint of film formation.

When the polyester substrate having a retardation of 3000 nm or more is used for the light-transmitting substrate 12, the thickness of the polyester substrate is preferably 15 μm or more and 500 μm or less. When the thickness is less than 15 μm, the retardation of the polyester base material cannot be 3,000 nm or more, and the anisotropy of mechanical properties becomes remarkable, and cracking, cracking, and the like are likely to occur, and the practicality as an industrial material is remarkably lowered. On the other hand, when it exceeds 500 μm, the peculiar flexibility of the polymer film is lowered, and the practicality as an industrial material may be lowered. A more preferred lower limit of the thickness of the above polyester substrate is 50 μm, more preferably an upper limit of 400 μm, and even more preferably an upper limit of 300 μm.

The light-transmitting substrate 12 having in-plane birefringence is not particularly limited as long as it has a retardation of 3000 nm or more, and examples thereof include an acrylic substrate, a polyester substrate, a polycarbonate substrate, and a cycloolefin polymer. Substrate, etc. Among these, a polyester base material is preferred from the viewpoint of cost and mechanical strength.

The polyester used for the polyester substrate may be a copolymer of the above polyester or the like, or may be mainly composed of the above polyester (for example, a component of 80 mol% or more), and a small ratio (for example, 20 mol%). The other types of resins of the following) are blended. Polyethylene terephthalate as polyester or Polyethylene-2,6-naphthalate is particularly excellent because of a good balance between mechanical properties and optical properties. In particular, polyethylene terephthalate is preferred because it has high versatility and is easy to obtain. In the present invention, an optical film which can produce a liquid crystal display device having high display quality can be obtained even if a film having extremely high generality such as polyethylene terephthalate is used. Further, since polyethylene terephthalate is excellent in transparency, heat or mechanical properties, it is easy to obtain a large retardation even if the inherent birefringence is large and the film thickness is thin, because of the excellent transparency, thermal or mechanical properties.

For example, a method of obtaining a polyester substrate having a retardation of 3000 nm or more, for example, a polyester obtained by melting a polyester such as polyethylene terephthalate, and extruding into a sheet-like shape, is in the glass. A method of applying heat treatment after stretching laterally using a tenter or the like at a temperature higher than the transfer temperature. The lateral extension temperature is preferably 80 to 130 ° C, more preferably 90 to 120 ° C. Further, the lateral stretching ratio is preferably from 2.5 to 6.0 times, more preferably from 3.0 to 5.5 times. When the lateral stretching ratio exceeds 6.0 times, the transparency of the obtained polyester substrate 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 substrate is small, and the desired property is obtained. The film thickness for retardation becomes thicker. Further, when the polyester base material is extruded into a sheet shape, it may be extended in the flow direction (mechanical direction), that is, in the longitudinal direction. In this case, the value of the refractive index difference Δn is stably ensured in the above preferred range, and the stretching ratio of the longitudinal stretching is preferably 2 or less. Further, in the longitudinal direction of the extrusion molding, the longitudinal stretching of the unstretched polyester may be carried out under the above conditions, and then the longitudinal stretching may be carried out. Further, the treatment temperature in the above heat treatment is preferably 100~ 250 ° C, more preferably 180 ~ 245 ° C.

A method of controlling the retardation of the polyester substrate produced by the above method to 3,000 nm or more, 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 and the thicker the film thickness, the easier it is to obtain a high retardation, the lower the stretching ratio, the higher the stretching temperature, and the thinner the film thickness, the easier it is to obtain a lower yield. Delay.

<intermediate layer>

Next, the intermediate layer 13 will be described in detail. The intermediate layer 13 can reflect the light L _r1 and the intermediate layer 13 at the interface between the functional layer 15 and the intermediate layer 13 by lightly satisfying the above conditions regarding the thickness t [nm] and the average refractive index n _{2 in} the plane thereof. The light intensity (amplitude) of the synthesized reflected light L _r formed by the overlapping of the reflected light L _{r2 at} the interface of the substrate 12 is lowered, and the interference fringes caused by the combined reflected light L _r are suppressed from being recognized. The intermediate layer 13 is not particularly limited as long as it satisfies the above conditions regarding the thickness t [nm] and the average refractive index n ₂ in the plane.

Further, the intermediate layer 13 may have a function of reducing the light intensity (amplitude) of the synthesized reflected light L _r and suppressing the occurrence of interference fringes. The underlayer may form the intermediate layer 13 by, for example, adjusting the underlayer, more specifically, the thickness of the underlayer and the average refractive index in the plane as an easy-to-layer function. According to such an example, it is possible to eliminate the necessity of providing a new intermediate layer 13 in the laminate 10 from the viewpoint of preventing the occurrence of interference fringes. On the contrary, in order to ensure that the layer provided for easy adhesion or the like can be used for the invisibility of the interference fringe, it is highly desirable from the viewpoint of the material cost of the laminate 10.

Therefore, the intermediate layer 13 can be composed of the same material as the known underlayer. Specifically, the resin contained in the intermediate layer 13 is, for example, a polyurethane resin, a polyester resin, a polyvinyl chloride resin, a polyvinyl acetate resin, a vinyl chloride-vinyl acetate copolymer, or an acrylic resin. a polyvinyl alcohol-based resin, a polyvinyl acetal resin, a copolymer of ethylene and vinyl acetate or acrylic acid, a copolymer of ethylene and styrene and/or butadiene, a thermoplastic resin such as an olefin resin, and/or It is composed of at least one of a modified resin, a polymer of a photopolymerizable compound, and a thermosetting resin such as an epoxy resin.

The above photopolymerizable compound may have at least one photopolymerizable functional group. In the present specification, the "photopolymerizable functional group" is a functional group capable of undergoing polymerization by light irradiation. The photopolymerizable functional group may, for example, be an ethylenic double bond such as a (meth)acryl fluorenyl group, a vinyl group or an allyl group. Moreover, "(meth)acryloyl group" means both "acryloyl group" and "methacryloyl group". Further, the light to be irradiated when the photopolymerizable compound is polymerized is, for example, visible light, ultraviolet rays, X-rays, electron beams, α rays, β rays, and gamma rays.

The photopolymerizable compound is, for example, a photopolymerizable monomer, a photopolymerizable oligomer, or a photopolymerizable polymer, and can be appropriately adjusted and used. The photopolymerizable compound is preferably a combination of a photopolymerizable monomer and a photopolymerizable oligomer or a photopolymerizable polymer.

When the functional layer 15 to be described later is formed using a photopolymerizable compound, it is preferred to add a polymerization initiator which can start polymerization of the photopolymerizable compound to the intermediate layer 13. Thereby, when the functional layer 15 is hardened, the middle layer can be made The interlayer 13 is strongly crosslinked with the functional layer 15.

In order to adjust the refractive index of the intermediate layer 13, the resin may contain fine particles having a particle diameter of, for example, 100 nm or less. For example, in order to lower the refractive index of the intermediate layer 13, the intermediate layer may contain low refractive index particles such as cerium oxide or magnesium fluoride, or in order to increase the refractive index of the intermediate layer 13, the intermediate layer may contain titanium oxide or zirconium oxide. Metal oxide particles.

From the viewpoint of making the interference fringes invisible, the thickness of the intermediate layer 13 can be set to satisfy any of the above conditions (c1) to (c5). The average refractive index n _{2 in} the plane of the intermediate layer 13 can be set to satisfy one of the above conditions (a) and (b), and satisfy any of the conditions (c1) to (c5), and can be set, for example, to 1.40 or more and 1.80 or less.

However, the intermediate layer 13 may have an in-plane birefringence. The light-transmitting substrate 12 having in-plane birefringence will be described below.

The intermediate layer 13 having in-plane birefringence can be formed by orienting a molecule having a refractive index anisotropy (for example, a liquid crystal molecule) or a compound. The intermediate layer 13 is obtained by applying a composition containing a refractive index anisotropic molecule or a refractive index anisotropic compound to a light-transmitting substrate 12 and curing the composition. For example, when the light-transmitting substrate 12 is formed of 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 property and a light-transmitting group. The molecular alignment of the material 12 is aligned to correspond to the regularity. Thereby, the obtained intermediate layer 13 becomes in-plane birefringence corresponding to the birefringence of the light-transmitting substrate 12, and therefore the intermediate layer 13 can satisfy the above conditions (f) to (n). Further, the refractive index anisotropic molecule contained in the intermediate layer 13 Or the viewpoint that the alignment of the refractive index anisotropic compound is more stable depends not only on the alignment of the light-transmitting substrate 12 but also on the refractive index anisotropic molecules contained in the intermediate layer 13 by frictional alignment or photoalignment. Or the refractive index anisotropy compound is actively aligned.

Further, another method is to obtain the intermediate 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 intermediate layer 13 is formed on the light-transmitting substrate 12 before stretching, and the light-transmitting substrate 12 and the intermediate layer 13 are simultaneously extended to impart birefringence to the light-transmitting substrate 12, and it is also possible to The intermediate layer 13 imparts birefringence corresponding to the birefringence of the light-transmitting substrate 12 .

More specifically, first, the composition constituting the intermediate 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 the intermediate layer 13. As the material constituting the intermediate 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, 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 intermediate layer 13. The above-mentioned various resin films can be used for the light-transmitting substrate 12 to which the composition of the intermediate layer 13 is applied. However, at the time of extrusion molding, a resin film which is stretched at a low magnification in the machine direction is preferable. By extending in the machine direction (the extrusion direction at the time of extrusion molding of the light-transmitting substrate 12), the flatness of the light-transmitting substrate 12 can be ensured, and thus it can be formed on the light-transmitting substrate 12. Intermediate layer 13 Homogenize.

Thereafter, the laminated base material 11 including the light-transmitting substrate 12 and the intermediate layer 13 formed on the light-transmitting substrate 12 is orthogonal to the machine direction in a state of being heated to a glass transition temperature or higher. Extend in the horizontal 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 polyester terephthalate. The slow axis of the light-transmitting substrate 12 composed of the film extends approximately in the lateral direction. The intermediate layer 13 is only extended in the lateral direction. Therefore, even if the intermediate layer 13 is formed by a resin material which is more difficult to impart birefringence than the light-transmitting substrate 12, it is possible to impart a certain degree of orientation corresponding to the birefringence of the light-transmitting substrate 12. Birefringence of the opposite sex.

According to the above method, by imparting the birefringence stretching treatment to the light-transmitting substrate 12, not only the light-transmitting substrate 12 but also the intermediate layer 13 can be imparted with birefringence. Further, since the light-transmitting substrate 12 and the intermediate layer 13 are extended while being heated, the advantage of improving the adhesion between the light-transmitting substrate 12 and the intermediate layer 13 can be obtained.

Regarding the respective refractive indices n ₂ , n _2x , n _2y , n _2a , and n _2b of the intermediate layer 13 (see FIGS. 4 and 5 ), as described above, the refractive indices n ₁ and n of the light-transmitting substrate 12 are as described above. The respective refractive indices n ₃ , n _3x , and n _{3y of 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 made of a polyethylene terephthalate film and the functional layer 15 functions as a hard coat layer, the refractive index n ₂ of the intermediate layer 13 can be set to 1.50 to 1.70. The refractive index n _2x of the intermediate layer 13 can be set to 1.55 to 1.75, the refractive index n _2y of the intermediate layer 13 can be set to 1.45 to 1.65, and the refractive index n _2a of the intermediate layer 13 can be set to 1.55 to 1.75, and the intermediate layer The above refractive index n _{2b of} 13 can be set to 1.45 to 1.65.

<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 laminate 10, and specifically, for example, a layer which exhibits functions such as hard coatability, antireflection property, antistatic property, and antifouling property. . 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 intermediate layer 13 of the laminated substrate 11. Further, in the laminate 10 shown in Fig. 2, the functional layer 15 is formed of a hard coat layer formed on one surface of the intermediate layer 13, and the second functional layer 17 is formed on the opposite side of the intermediate layer 13 from the hard coat layer. The low refractive index layer is formed on the surface. 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.

The hard coat layer is a layer for improving the scratch resistance of the optical film, specifically, a pencil hardness test (4.9 N load) prescribed by JIS K5600-5-4 (1999), and having a hardness of "H" or more. The layer is preferred. In one example of the hard coat layer, a composition for a hard coat layer containing a photopolymerizable compound is applied onto the intermediate layer 13, and after drying, the film-form hard coat layer composition is irradiated with light such as ultraviolet rays to cause photopolymerization. The compound is obtained by polymerization (crosslinking).

The hard coat layer produced by this method is optically isotropic without in-plane birefringence. The average refractive index n _{3 in} the plane of the functional layer 15 of the obtained hard coat layer may be 1.45 to 1.65. 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 photopolymerizable compound is, for example, a photopolymerizable monomer, a photopolymerizable oligomer, or a photopolymerizable polymer, and these can be appropriately adjusted and used. The photopolymerizable compound is preferably a combination of a photopolymerizable monomer and a photopolymerizable oligomer or a photopolymerizable polymer.

Photopolymerizable monomer

The photopolymerizable single system has a weight average molecular weight of less than 1,000. The photopolymerizable monomer is preferably a polyfunctional monomer having two (i.e., bifunctional) or more photopolymerizable functional groups. In the present specification, the "weight average molecular weight" is a value obtained by dissolving in a solvent of a conventionally known gel permeation chromatography (GPC) method after being dissolved in a solvent such as THF.

A monomer having two or more functional groups, for example, trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(methyl) Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol Di(meth)acrylate, trimethylolpropane tri(meth)acrylate, bis(trimethylol)propane IV (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, pentaerythritol deca (meth) acrylate, isocyanuric acid tri(meth) acrylate, isocyanide Uric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, dipropanetriol tetra(meth)acrylate , adamantyl di(meth) acrylate, isobornyl di (meth) acrylate, dicyclopentane di (meth) acrylate, tricyclodecane di (meth) acrylate, di (three) Hydroxymethyl)propane tetra(meth)acrylate, or such modified by PO, EO, etc.

Among these, a monomer having three or more functional groups such as pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (preferably, from the viewpoint of obtaining a high-hardness antiglare layer) is preferable. PETTA), dipentaerythritol pentaacrylate (DPPA), and the like.

Photopolymerizable oligomer

The photopolymerizable oligomer has a weight average molecular weight of 1,000 or more and less than 10,000. The photopolymerizable oligomer is preferably a difunctional or higher polyfunctional oligomer. Polyfunctional oligomers are, for example, polyester (meth) acrylate, urethane (meth) acrylate, polyester urethane (meth) acrylate, polyether (meth) acrylate Ester, polyol (meth) acrylate, melamine (meth) acrylate, isocyanurate (meth) acrylate, epoxy (meth) acrylate, and the like.

Photopolymerizable polymer

When the weight average molecular weight of the photopolymerizable polymer is 10,000 or more, the weight average molecular weight is preferably 10,000 or more and 80,000 or less, more preferably 10,000 or more and 40,000 or less. When the weight average molecular weight exceeds 80,000, the coating property is lowered due to the high viscosity, and the appearance of the obtained optical laminate may be deteriorated. The above polyfunctional polymer is, for example, a urethane (meth) acrylate, an isocyanurate (meth) acrylate, a polyester urethane (meth) acrylate, an epoxy group. (Meth) acrylate, etc.

In addition to the above fine particles and the photopolymerizable compound, a composition for a hard coat layer may be added with a thermoplastic resin, a thermosetting resin, a solvent, or a polymerization initiator. In order to increase the hardness of the hard coat layer, suppress the hardening shrinkage, or control the refractive index, etc., a conventionally used dispersant, surfactant, antistatic agent, decane coupling agent, and viscosity-increasing may be added as necessary. Agents, anti-colorants, colorants (pigments, dyes), antifoaming agents, flat agents, flame retardants, ultraviolet absorbers, adhesion-imparting agents, polymerization inhibitors, antioxidants, surface modifiers, slip agents, and the like.

In particular, from the viewpoint of adjusting the refractive index of the functional layer 15 and satisfying one of the above conditions (a) and (b), the functional layer-forming composition (hard-coating layer-forming composition) may contain a fine particle diameter, for example Particles below 100 nm. For example, in order to lower the refractive index of the functional layer 15, the functional layer may contain low refractive index particles such as cerium oxide or magnesium fluoride, or in order to increase the refractive index of the functional layer 15, the functional layer may contain titanium oxide or Metal oxide particles such as zirconia.

The thermoplastic resin to be added to the composition for a hard coat layer is preferably amorphous, and is soluble in an organic solvent (particularly, a common solvent which can dissolve a plurality of polymers or a curable compound). In particular, from the viewpoint of transparency and weather resistance, a styrene resin, a (meth)acrylic resin, an alicyclic olefin resin, a polyester resin, a cellulose derivative (cellulose ester, etc.) are preferable. )Wait.

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

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 refractive index smaller than that 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 is 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 includes a polyfluorene-containing oxygen in addition to the above resin material. The polymer, the fluorine-containing copolymer, and the fine particles can be adjusted in refractive index. The above-mentioned polyoxymethylene-containing copolymer may, for example, contain a polyoxyethylene vinylene copolymer. Further, specific examples of the fluorine-containing copolymer include, for example, 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, the "fine particles having a void" means a structure in which a gas is filled inside a fine particle and/or a porous structure containing a gas, and the refractive index of the fine particles and the gas in the fine particles are compared with each other. In inverse proportion, the particles have a reduced refractive index.

Further, here, the functional layer 15 is formed 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. 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 provided in addition to at least one of the hard coat layer and the low refractive index layer, 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. Average particle size of the above microparticles The diameter 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), melamine beads (refractive index 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 less likely to adhere to the outermost surface of the liquid crystal display device, or is easy to wipe off even if it adheres. Further, by forming the above-described 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 preferred 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. The above antifouling layer can also be prevented, for example The staining properties impart a replacement to the hard coat itself.

<Layer>

In the first embodiment, the intermediate layer 13 can be provided between the functional layer 15 and the light-transmitting substrate 12 in accordance with the laminate 10 described above. The average refractive index n _{1 in} the plane of the light-transmitting substrate 12, the average refractive index n ₂ in the plane of the intermediate layer 13 , the average refractive index n _{3 in} the plane of the functional layer 15 , and the thickness t of the intermediate layer 13 are adjusted. [nm] satisfies one of the above conditions (a) and (b), and satisfies at least one of the conditions (c1) to (c5). The results can be effectively reduced by the incident side of the functional layer 15 in the laminate 10, the reflected light L _r2 13 overlaps with the light-transmitting substrate interface and the intermediate layer L _r1 light reflecting layer 15 and the interface function of the intermediate layer 13 of 12 The light intensity (amplitude) of the resultant synthesized reflected light L _r . Therefore, the identifiable interference fringes caused by the interference of the light reflected from the surface of the laminate 10 and the light reflected inside the laminate 10 can be effectively made inconspicuous.

Moreover, average refractive index n of the inner surface 12 of the transparent substrate _1, an average refractive index n ₃ is adjusted to satisfy the above conditions in the plane average refractive index n 13 of the inner surface of the intermediate layer ₂ and the functional layer 15 (a And one of the conditions (b), there is no optical interface in which the refractive index greatly changes between the light-transmitting substrate 12 and the functional layer 15. In other words, between the light-transmitting substrate 12 and the functional layer 15, there is no interface in which the reflectance is high because the refractive index difference is large. 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 reaches the light-transmitting substrate 12 and is reflected. Thereby, the identifiable interference fringes caused by the interference between the light reflected from the surface of the laminate 10 and the light reflected inside the laminate 10 can be effectively made inconspicuous.

Further, by setting the retardation of the light-transmitting substrate 12 to 3,000 nm or more, the rainbow spots can be made inconspicuous. Therefore, according to the laminate 10 described herein, both the rainbow spots and the interference fringes can be effectively made inconspicuous. In addition, it is also suitable for viewing through sunglasses.

Further, when the intermediate layer 13 is realized by the underlayer, there is no substantial increase in material cost or an increase in manufacturing steps, and the above-described useful effects can be ensured.

Polarizer

The laminate 10 can be used, for example, in the polarizing plate 20. Fig. 7 is a schematic configuration diagram of a polarizing plate 20 assembled to the laminate 10 shown in the drawing. As shown in FIG. 7, 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 the surface opposite to the surface of the functional layer 15 of the laminated substrate 11. 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, a polyvinyl alcohol film, a polyvinyl acetal film, a polyethylene acetal film, or an ethylene-vinyl acetate copolymer saponified film which is dyed with iodine or the like.

"Liquid Crystal Display Panel"

The laminate 10 and the polarizing plate 20 can be assembled for use in a liquid crystal display panel. Figure 7 is a laminate 10 shown in Figure 1 and the bias shown in Figure 6 A schematic configuration diagram of the liquid crystal display panel 30 of the light panel 20.

The liquid crystal display panel shown in FIG. 7 has a protective film 31, a polarizing element 32, and a retardation film which are sequentially laminated with a triethylene fluorene-based cellulose film (TAC film) from the light source side (backlight unit side) toward the viewer side. 33. Structure of 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. The liquid crystal 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 may be the same as the protective film 22. The adhesive constituting the adhesive layers 34 and 36 is, for example, a pressure sensitive adhesive (PSA).

Image Display Device

The laminate 10, the polarizing plate 20, and the liquid crystal display panel 30 can be assembled and used in 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. 8 is a schematic configuration diagram of a liquid crystal display in which an example of the image display device 40 of the laminate 10 shown in FIG. 1, the polarizing plate 20 shown in FIG. 6, and the liquid crystal display panel 30 shown in FIG.

The image display device 40 shown in Fig. 8 is a liquid crystal display. The image display device 30 is further connected to the backlight unit 41 by the backlight unit 41 The liquid crystal display panel 30 including the laminate 10 disposed near the observer side is configured. The backlight unit 41 can use a conventional backlight unit.

Touch Panel Sensor and Touch Panel Device

Moreover, the laminate 10 can be used as a part of the touch panel sensor and the touch panel as applications other than the above applications. FIG. 9 is a schematic configuration diagram of the touch panel sensor 50 and the touch panel device 55 in which the laminate 10 shown in FIG. 1 is assembled.

As shown in FIG. 9 , the touch panel sensor 50 has a laminate 10 and a sensor electrode 51 . The sensor electrode 51 is formed on the surface opposite to the surface on which the functional layer 15 of the laminated substrate 11 is formed. The touch panel device 55 has a touch panel sensor 50 and a control device 53 for electrically connecting the sensor electrodes 51 of the touch panel sensor 50. The control device 53 is configured to detect the contact position based on the current value that changes the contact position on the functional layer 15.

An example of the touch panel device 55 shown in FIG. 9 is a capacitive touch panel that constitutes a surface type. Therefore, the sensor electrodes 51 are formed in a planar shape, and the four corners of the sensor electrodes 51 are electrically connected to the control device 53. The touch panel device 55 and the touch panel sensor 50 are not limited to the example shown in FIG. 9 and may be configured by a projection type electrostatic capacitance method or a resistive film method.

"Other uses"

The above laminate 10 can be used for various purposes to avoid interference fringes. way. For example, the laminate 10 can be used as a window material for a display portion of a machine such as a clock or a meter.

"Second embodiment"

Next, a second embodiment of the present invention will be described. Fig. 10 is an explanatory view showing a second embodiment of the present invention. Fig. 10 is an explanatory view showing a waveform of light reflected in the laminate of the second embodiment, corresponding to the second embodiment of Fig. 3; Further, the relationship between the refractive indices of the respective layers of the laminate of the second embodiment and the thickness of the intermediate layer are different from those of the above-described first embodiment, and the other configurations can be the same as those of the first embodiment. Further, Fig. 1, Fig. 2, and Fig. 6 to Fig. 9 of the layer configuration are common drawings in the second embodiment. In the respective configurations of the second embodiment to be described below, the same reference numerals are used for the corresponding configurations of the first embodiment, and the description overlapping with the first embodiment will be omitted.

Laminated body <The whole composition of the laminate>

First, the overall configuration of the laminate 10 of the second embodiment will be described. As shown in Fig. 1, the laminate 10 of the second embodiment has a laminated base material 11 and a functional layer 15 formed on one surface of the laminated base material 11 as in the first embodiment. The laminated base material 11 has a light-transmitting base material 12 and an intermediate layer 13 laminated with the light-transmitting base material 12. In the laminate 10, the intermediate layer 13 is located between the light-transmitting substrate 12 and the functional layer 15. In other words, the functional layer 15 is laminated on the laminated substrate 11 from the intermediate layer 13 side. In the example of the figure, the layer In the base material 11, the intermediate layer 13 is formed on one surface of the light-transmitting substrate 12. In other words, the laminate 10 is composed of three layers of the light-transmitting substrate 12, the intermediate layer 13, and the functional layer 15, and the intermediate layer 13 is disposed adjacent to the light-transmitting substrate 12 and the functional layer 15, respectively. An interface is formed between the optical substrate 12 and the functional layer 15.

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

The laminate 10 described herein satisfies one of the following conditions (o) and (p), while satisfying at least the following condition (q1).

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t<λ _max /(12×n ₂ ). . . Condition (q1)

In the conditions (o) to (q1) and the conditions (q2) to (q6) to be described later, "n ₁ " is the average refractive index in the plane of the light-transmitting substrate 12, and "n ₂ " is the intermediate layer 13 The average refractive index in the plane, "n ₃ ", is the average refractive index in the plane of the functional layer 15. Further, in the condition (q1) and the conditions (q2) to (q6) described later, "λ _max " is the longest wavelength [nm] of visible light, and "λ _min " is the shortest wavelength [nm] of visible light, and "t" is the middle. The thickness of layer 13 [nm]. The average refractive index in the plane refers to the average value of the refractive indices in two directions orthogonal to each other along the thin one-sided extension of the sheet-like layer to be the object. When the target layer is optically isotropic, the refractive index in each direction along the sheet surface of the layer is the same. However, when the target layer is optically anisotropic, the refractive index in each direction along the sheet surface of the layer is not the same.

The "sheet surface (film surface, plate surface)" refers to a film-like (film-like, plate-shaped) member to be applied, and when viewed as a whole and in a large position, it corresponds to the planar direction of the target film-like member. surface. In the laminate 10 described in one embodiment, the sheet surface of the light-transmitting substrate 12, the sheet surface of the intermediate layer 13, the sheet surface of the functional layer 15, the sheet surface of the second functional layer 17, and the laminated substrate 11 The sheet faces and the sheet faces of the laminate 10 are parallel to each other.

In the second embodiment, the refractive index in each of the planes of the respective layers, the average refractive index n ₁ , n ₂ , n _{3 in} the plane of each layer, and the thickness of the intermediate layer 13 (at the time of curing) t can be used in the first embodiment. The method described in the form is determined.

When the laminate 10 satisfies one of the above conditions (o) and (p), and at least the condition (q1) is satisfied, interference fringes in the laminate 10 can be effectively suppressed. Among them, the interference fringe which is the object of invisibility is the reflected light on the surface of the functional layer 15 among the light (the light L _{i of} FIG. 10 ) from the functional layer 15 side to the laminate 10 of FIG. 1 and the laminated substrate The interference fringes produced by the interference of the reflected light of 11 (light L _{r of} Fig. 10). Similarly, the reflected light on the surface of the second functional layer 17 or the reflected light at the interface between the second functional layer 17 and the functional layer 15 among the light from the second functional layer 17 side to the laminate 10 of FIG. 2 The interference fringes generated by the interference of the reflected light of the substrate 11 also become interference fringes of the object of invisibility. The reflected light from the laminated substrate 11 refers to the reflected light at the interface between the functional layer 15 and the intermediate layer 13 (light L _{r1 in} FIG. 10 ) and the reflected light at the interface between the intermediate layer 13 and the light-transmitting substrate 12 . (Light L _{r2 in} Figure 10).

As described below, when one of the conditions (o) and (p) is satisfied and the condition (q1) is satisfied, the light in the wavelength region of at least a part of the visible light region can be effectively reduced so that the inside of the laminate 10 is lowered. The functional layer 15 is laterally laminated on the side of the substrate 11 and is reflected by the laminated base material 11 to return the intensity of light on the functional layer 15 side. In other words, by reducing the intensity of the light causing the interference fringes, the interference fringes caused by the light in the wavelength region of at least a part of the visible light region can be made inconspicuous.

A method of making the interference fringes generated by the laminate invisible, for example, a method of blurring the interface in the laminate by providing a mixed existence region and a method of forming irregularities on the surface of the laminate. However, as described above, in the method of providing the mixed existence region, in order to secure the strength of the laminate 10, it is necessary to increase the thickness of the functional layer. Therefore, when this method is employed, the material cost is increased, and an unsatisfactory state in which the manufacturing cost of the laminate 10 rises is caused. Moreover, when the method of forming the unevenness on the surface of the laminated body 10 is used, the image quality of the image observed by the laminated body 10 deteriorates. Specifically, the screen produces a white turbidity, reduces contrast, and the gloss or brilliance of the image disappears.

In this regard, one of the conditions (o) and (p) is satisfied, At the same time, the laminate 10 satisfying the condition (q1) does not need to provide a mixed existence region and does not need to increase the thickness of the functional layer. Further, when the intermediate layer 13 is used as an example, for example, by a primer layer such as an easy-adhesion layer, it is not necessary to provide an additional layer in the laminate 10 for the purpose of the interference stripe countermeasure, and the cost side is not generated. The shortcomings. Further, a polyester base material which is difficult to mix the existing region itself can be provided, and can be used as the light-transmitting substrate 12. The light-transmitting substrate 12 composed of a polyester base material is excellent in cost, stability, and the like.

Further, the laminate 10 satisfying the condition (o) and the condition (p) while satisfying the condition (q1) does not need to cause diffusion, so that the surface is kept smooth and the occurrence of interference fringes can be effectively prevented. Therefore, the image quality of the image observed through the laminate 10 is not adversely affected, and the interference fringes can be made invisible. In other words, the laminate 10 satisfying the condition (o) and the condition (p) while satisfying the condition (q1) imparts luster and brilliance to the display image, and prevents the occurrence of white turbidity and interference fringes.

Here, with reference to FIG. 10, by satisfying one of the condition (o) and the condition (p), the interference fringe invisible function exhibited by the laminate 10 satisfying the condition (q1), in other words, the occurrence of interference fringes is suppressed. That is, the function of the interference fringe being visually confirmed, and the function of replacing the interference fringe is not obvious.

When one of the conditions (o) and (p) is satisfied, the light incident on the laminated body 10 from the side of the functional layer 15 is at the interface between the functional layer 15 and the intermediate layer 13 and the interface between the intermediate layer 13 and the light-transmitting substrate 12. One of the parties The interface is free-end reflective and the other interface is reflected at the fixed end. The laminate 10 shown in Fig. 10 satisfies the condition (p) in the condition (o) and the condition (p), and the light incident on the laminate 10 from the side of the functional layer 15 at the interface between the functional layer 15 and the intermediate layer 13 The fixed end reflection shifts the phase by π [rad], the interface between the intermediate layer 13 and the light-transmitting substrate 12, and the free end reflection maintains the phase.

As shown in the example of FIG. 10, the cross section along the normal direction nd of the laminated body 10 is shown. 10 shows the incident light L _i incident on the laminate 10 from the functional layer 15 side, the reflected light L _r1 reflected at the interface between the functional layer 15 and the intermediate layer 13 , and the intermediate layer 13 and the light-transmitting substrate 12 . The reflected light L _r2 reflected by the interface and the combined reflected light L _r synthesized by the reflected light L _r1 and the reflected L _{r2 are} in a vibrating state at a certain moment. As shown in FIG. 10, the x-axis extends in the normal direction of the laminate 10, and the y-axis extends at the interface between the functional layer 15 and the intermediate layer 13, so that when the xy coordinates are set, the lights L _i , L _r1 , L _r2 , The waveforms of L _r are represented by the following equations (8) to (11). In the following formulas (8) to (11), "λ" is the wavelength [nm] of light.

Y _i =sin((x×n ₃ /λ)×2π). . . Formula (8)

Y _r1 =sin((x×n ₃ /λ)×2π). . . Formula (9)

Y _r2 =-sin(((x×n ₃ /λ)+(2t×n ₂ /λ))×2π). . . Formula (10)

Y _r =-2. Sin(2t×n ₂ ×π/λ). Cos(((x×n ₃ /λ)+(t×n ₂ /λ))×2π). . . Formula (11)

In other words, the intensity of the combined reflected light L _r of the laminated base material 11 that causes the interference fringes is expressed by "2.cos (2t.n ₂ .π/λ)" indicating the amplitude of the waveform of the light. The weaker the intensity of the interference fringe-synthesized reflected light L _r , the less noticeable it becomes. Therefore, when the following equation (12) is satisfied that the amplitude of the synthesized reflected light L _r is less than one-half of the maximum value ("2") (not "1"), the interference fringes generated by the light of the wavelength λ are not The obvious point of view is that it is a better condition. When the amplitude (1) is exceeded by one half of the maximum value, the interference fringes caused by the light of the wavelength λ are not conspicuous, which is a poor condition.

t<λ/(12×n ₂ ). . . Formula (12)

t>λ/(12×n ₂ ). . . Formula (13)

As described above, when the condition (p) and the condition (q1) are satisfied, it is possible to effectively prevent the light in the visible light wavelength region including at least a part of the light having the longest wavelength of visible light from being recognized by the interference fringe. In other words, with respect to at least a portion of the visible light, the interference fringes can be effectively made invisible.

Further, with respect to the replacement condition (p), when the condition (o) and the condition (q1) are satisfied, the interference fringes can be effectively made invisible with respect to light containing at least a part of the visible light wavelength region. When the condition (o) is satisfied, the light incident on the laminated body 10 from the functional layer 15 side is at the interface between the intermediate layer 13 and the light-transmitting substrate 12, and the free end is reflected, and the phase is shifted by π [rad], and the functional layer 15 is At the interface of the intermediate layer 13, the free end reflection maintains the phase. Therefore, with respect to the incident light Li of FIG. 10, only the light having a phase retardation of π [rad] is incident on the laminated body 10 satisfying the condition (o) and the condition (q1) from the functional layer 15 side, and the reflection of the laminated substrate 11 is performed. The light exhibits the same waveforms as the reflected lights L _r1 , L _r2 , and L _r as shown in FIG. 10 . From this point of view, even when the condition (o) and the condition (q1) are satisfied instead of the condition (p), the interference fringes can be effectively made invisible for at least a part of the visible light.

As described above, when one of the above conditions (o) and (p) and the condition (q1) are satisfied, it is possible to effectively prevent the light in the visible light wavelength region including at least a part of the light having the longest wavelength of visible light from being recognized by the interference fringe. In other words, when one of the above conditions (o) and (p) and the condition (q1) are satisfied, the interference fringes can be effectively made invisible for at least a part of the visible light. In other words, when one of the above conditions (o) and (p) and the condition (q1) are satisfied, it is expected to find an interference fringing invisible function that the observer can perceive (a function that makes the interference fringes inconspicuous).

From the viewpoint of making the interference fringes invisible, it is preferable to satisfy one of the above conditions (o) and (p) while satisfying the following condition (q2).

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t<((λ _min +λ _max )/2)/(12×n ₂ ). . . Condition (q2)

When one of the above conditions (o) and (p) is satisfied, and the following condition (q2) is satisfied, the interference fringe is invisible for light having a wavelength region of one or more half of the visible light range. Features. In other words, when one of the above conditions (o) and (p) is satisfied and the following condition (q2) is satisfied, the interference fringes caused by light in one or more half wavelength regions in the visible light region can be effectively made invisible.

Further, from the viewpoint of making the interference fringes invisible, one of the above conditions (o) and (p) is satisfied, and the following conditions are satisfied. (q3) is better.

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t<(λ _min /2)/(12×n ₂ ). . . Condition (q3)

When one of the above conditions (o) and (p) is satisfied, and the following condition (q3) is satisfied, the function of making the interference fringes invisible can be effectively exhibited for the light in the entire region in the visible light region. In other words, when one of the above conditions (o) and (p) is satisfied while the condition (q3) is satisfied, interference fringes of all colors can be effectively prevented from being recognized.

Further, according to the definition of JIS Z8120, the longest wavelength λ _max in the visible light wavelength region is 830 nm, and the shortest wavelength λ _{min in the} visible light wavelength region may be 360 nm.

Further, from the viewpoint of making the interference fringes invisible, it is also effective to satisfy one of the above conditions (o) and (p) while satisfying the following condition (q4) or condition (q5).

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

0<t[nm]<555/(12×n ₂ ). . . Condition (q4)

0<t[nm]<507/(12×n ₂ ). . . Condition (q5)

The International Commission on Illumination (CIE) reports that people's sensitivities are different for light in each wavelength region in the visible region. According to the International Commission on Illumination (CIE), the light wavelength that people can easily feel is 555 nm when they are in a bright place. When they are in a dark place, the light wavelength that people can easily feel is 507 nm. Therefore, one of the conditions (o) and conditions (p) and conditions are met. (q4), in the bright area, the light in the wavelength region that is most easily perceived by humans can effectively exhibit the interference fringe invisibility function. In other words, when one of the condition (o) and the condition (p) and the condition (q4) are satisfied, interference fringes which can be recognized in a bright place can be effectively prevented. Further, when one of the conditions (o) and (p) and the condition (q5) are satisfied, not only the light in the wavelength region which is most easily perceived by the human being in the bright portion but also the light in the wavelength region which is most easily perceived by the human being in the dark portion It can effectively exert the function of invisibility of interference fringes. In other words, when one of the conditions (o) and (p) and the condition (q5) are satisfied, it is possible to effectively prevent the interference fringes from being recognized in bright places and dark places.

In addition, when the inventors of the present invention have carefully obtained the results and satisfied one of the above conditions (o) and (p), and satisfy the following condition (q6), it is possible to very effectively suppress the interference fringes from being recognized even if attention is observed.

n ₁ >n ₂ and n ₂ <n ₃ . . . Condition (o)

n ₁ <n ₂ and n ₂ >n ₃ . . . Condition (p)

3≦t[nm]≦30. . . Condition (q6)

Further, not only the above formula (12) but also the expression (12') below the natural number k is used, and the interference fringes caused by the light of the wavelength λ are not made conspicuous. When the formula (12') is satisfied, only the optical path of the reflected light L _r2 becomes longer (λ × k) / (2 × n ₂ ) [nm], and the synthesized reflected light L _{r is} compared with the case where the formula (12) is satisfied. The waveform has not changed. Therefore, in the case where the formula (12') is satisfied, the same effects as those in the case of satisfying the formula (12) can be expected.

- λ / (12 × n ₂ ) < t - (k × λ) / (2 × n ₂ ) < λ / (12 × n ₂ ). . . Formula (12')

Therefore, when one of the conditions (o) and (p) and the condition (q1') are satisfied, the same operational effects as when one of the conditions (o) and (p) and the condition (q1) are satisfied can be expected.

- λ _max /(12 × n ₂ ) < t - (k × λ _max ) / (2 × n ₂ ) < λ _max / (12 × n ₂ ). . . Condition (q1')

In addition, for the same reason (q2) to condition (q5), in place of these conditions (q2) to (q5), when the following conditions (q2') to (q5') are satisfied, it is expected The same effect is obtained when the following conditions (q2) to (q5) are satisfied.

-(( λ _min +λ _max )/2)/(12×n ₂ )<t-(k×((λ _min +λ _max )/2))/(2×n ₂ )<((λ _min + λ _max )/2)/(12×n ₂ ). . . Condition (q2')

-λ _min /(12×n ₂ )<t-(k×λ _min )/(2×n ₂ )<λ _min /(12×n ₂ ). . . Condition (q3')

-555/(12×n ₂ )<t-(k×555)/(2×n ₂ )<555/(12×n ₂ ). . . Condition (q4')

-507/(12×n ₂ )<t-(k×507)/(2×n ₂ )<507/(12×n ₂ ). . . Condition (q5')

However, the substitution condition (q1) to condition (q5) satisfying the condition (q1') to the condition (q5') means that the thickness t [nm] of the intermediate layer 13 is increased. Therefore, from the viewpoint of the material cost, it is preferable to satisfy the condition (q1) to the condition (q5) when the condition (q1') to the condition (q5') are satisfied.

However, the prior art column has also been described. Recently, the light-transmitting substrate 12 may have in-plane birefringence. When the light-transmitting substrate 12 has an in-plane birefringence, the refractive index changes in each of the directions along the plane of the sheet surface of the light-transmitting substrate 12. In addition, in order to effectively exhibit the above-described interference fringe invisibility function, the average refractive index n _{1 in} the plane of the light-transmitting substrate 12 satisfies not only one of the above formulas (o) and (p) but also satisfies the following conditions ( One of r) and (s) is preferred.

n _1y >n ₂ and n ₂ <n ₃ . . . Condition (r)

n _1x <n ₂ and n ₂ >n ₃ . . . Condition (s)

Here, "n _1x " in the condition (s) is the value of the maximum refractive index in the in-plane of the light-transmitting substrate 12, that is, the refractive index in the slow axis direction. The "n _1y " in the condition (r) is the minimum refractive index direction in the plane of the light-transmitting substrate 12, that is, the value of the refractive index in the fast axis direction.

When one of the formula (r) and the condition (s) is satisfied, not only the average refractive index n ₁ in the plane of the light-transmitting substrate 12 but also the refractive index n in all directions in the plane of the light-transmitting substrate 12 _Arb satisfies one of the following conditions (t) and (u).

n _arb >n ₂ and n ₂ <n ₃ . . . Condition (t)

n _arb <n ₂ and n ₂ >n ₃ . . . Condition (u)

When one of the conditions (t) and (u) is satisfied, the direction of the slow axis in the plane of the light-transmitting substrate 12 causes the light of the polarized component of the vibration and the direction of the fast axis in the plane of the light-transmitting substrate 12, Both of the light that generates the polarized component of the vibration are reflected at the interface between the functional layer 15 and the intermediate layer 13 under the same conditions with respect to the phase deviation, and the intermediate layer 13 and the light transmittance are the same under the same conditions with respect to the phase deviation. The interface of the substrate 12 produces a reflection. In other words, when one of the condition (t) and the condition (u) is satisfied, the light in the laminated body 10 from the side of the functional layer 15 toward the side of the laminated substrate 11 does not depend on the state of polarization of the light, but is in the functional layer 15 and The interface between the intermediate layer 13 and one of the interfaces between the intermediate layer 13 and the light-transmitting substrate 12 is reflected at the free end and the other interface is reflected at the fixed end. Therefore, when one of the conditions (t) and (u) is satisfied, it is not effective depending on the polarization state. The above-described interference fringe invisibility function is exerted.

However, when one of the condition (o) and the condition (p) is satisfied, when both the condition (t) and the condition (u) are not simultaneously satisfied, the side of the laminated body 10 is moved from the side of the functional layer 15 toward the side of the laminated substrate 11 A part of the light depends on the polarized state of the light, and the free end reflection or fixed end is performed at the interface between the functional layer 15 and the intermediate layer 13 and the interface between the intermediate layer 13 and the light-transmitting substrate 12 reflection. With this kind of light, the above-described interference fringe invisibility function cannot be effectively exerted. However, when one of the conditions (o) and (p) is satisfied, the condition (t) and the condition (u) are not satisfied, and the laminate 10 is moved toward the side of the laminated substrate 11 from the functional layer 15 side. More light inside can effectively exert the function of making the above interference fringes invisible. In other words, when one of the conditions (o) and (p) is satisfied and any of the above conditions (q1) to (q6) is satisfied, the light incident on the laminated body 10 from the side of the functional layer 15 mainly affects the above interference. The stripe invisibility function effectively makes the interference fringes less noticeable.

Moreover, from the viewpoint of more effectively exhibiting the above-described interference fringe invisibility function, the average refractive index n _{3 in} the plane of the functional layer 15 is closer to the value of the average refractive index n _{1 in} the plane of the light-transmitting substrate 12 Preferably, the average refractive index n _{3 in} the plane of the functional layer 15 and the average refractive index n _{1 in} the plane of the light-transmitting substrate 12 are equal. As a result of intensive research by the inventors of the present invention, when the following condition (v) is satisfied, the interference fringe invisibility function can be more effectively exhibited.

|n ₁ -n ₃ |≦0.03. . . Condition (v)

<Light-transmitting substrate>

When the light-transmitting substrate 12 has light transmissivity, it is not particularly limited, and it satisfies the above conditions regarding the refractive index. For example, the light-transmitting substrate 12 can be similar to the light-transmitting substrate described in the first embodiment.

<intermediate layer>

Next, the intermediate layer 13 will be described in detail. The intermediate layer 13 can reflect the light L _r1 and the intermediate layer 13 at the interface between the functional layer 15 and the intermediate layer 13 by lightly satisfying the above conditions regarding the thickness t [nm] and the average refractive index n _{2 in} the plane thereof. The light intensity (amplitude) of the synthesized reflected light L _r formed by the overlapping of the reflected light L _{r2 at} the interface of the substrate 12 is lowered, and the interference fringes caused by the combined reflected light L _r are suppressed from being recognized. The intermediate layer 13 is not particularly limited as long as it satisfies the above conditions regarding the thickness t [nm] and the average refractive index n ₂ in the plane.

In other words, the thickness of the intermediate layer 13 can be set to satisfy any of the above conditions (q1) to (q6) from the viewpoint of making the interference fringes invisible. Further, the thickness of the intermediate layer 13 is preferably 3 nm or more from the viewpoint of uniformizing the film thickness. Further, the average refractive index n _{2 in} the plane of the intermediate layer 13 can be set to satisfy one of the above conditions (o) and (p), and satisfy any of the conditions (q1) to (q6), for example, can be set. It is 1.40 or more and 1.80 or less.

<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 attempted to perform a certain function in the laminated body 10. The layer is formed to satisfy the above conditions regarding the refractive index. Specifically, for example, the functional layer 15 and the second functional layer 17 have a function of exerting functions such as hard coatability, antireflection property, antistatic property, and antifouling property. 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 intermediate layer 13 of the laminated substrate 11. Further, in the laminate 10 shown in Fig. 2, the functional layer 15 is formed of a hard coat layer formed on one surface of the intermediate layer 13, and the second functional layer 17 is formed on the opposite side of the intermediate layer 13 from the hard coat layer. The low refractive index layer is formed on the surface. The hard coat layer as the functional layer 15 and the low refractive index layer as the second functional layer 17 can be similar to the hard coat layer and the low refractive index layer described in the first embodiment.

As described above, the average refractive index n _{3 in} the plane of the functional layer 15 is adjusted to be close to the average refractive index n _{1 in} the plane of the light-transmitting substrate 12 from the viewpoint of more effectively exhibiting the above-described interference fringe invisibility function. The value is equal or equal to the condition (v) is preferred.

|n ₁ -n ₃ |≦0.03. . . Condition (v)

In addition, from the viewpoint of adjusting the refractive index of the functional layer 15, the functional layer-forming composition (the composition for forming a hard coat layer) may contain fine particles having a small particle diameter, for example, 100 nm or less. For example, in order to lower the refractive index of the functional layer 15, the functional layer may contain low refractive index particles such as cerium oxide or magnesium fluoride, or in order to increase the refractive index of the functional layer 15, the functional layer may contain titanium oxide or Metal oxide particles such as zirconia.

<Layer>

According to the second embodiment, in the case of the laminate 10 described above, the intermediate layer 13 can be provided between the functional layer 15 and the light-transmitting substrate 12. The average refractive index n _{1 in} the plane of the light-transmitting substrate 12, the average refractive index n ₂ in the plane of the intermediate layer 13 , the average refractive index n _{3 in} the plane of the functional layer 15 , and the thickness t of the intermediate layer 13 are adjusted. [nm] satisfies one of the above conditions (o) and (p), and satisfies at least one of the conditions (q1) to (q6). The results can be effectively reduced by the incident side of the functional layer 15 in the laminate 10, the reflected light L _r2 13 overlaps with the light-transmitting substrate interface and the intermediate layer L _r1 light reflecting layer 15 and the interface function of the intermediate layer 13 of 12 The light intensity (amplitude) of the resultant synthesized reflected light L _r . Therefore, the identifiable interference fringes caused by the interference of the light reflected from the surface of the laminate 10 and the light reflected inside the laminate 10 can be effectively made inconspicuous.

Further, similarly to the first embodiment, by setting the retardation of the light-transmitting substrate 12 to 3,000 nm or more, the rainbow spots can be made inconspicuous. Therefore, according to the laminate 10 described herein, both the rainbow spots and the interference fringes can be effectively made inconspicuous. In addition, it is also suitable for viewing through sunglasses.

Further, when the intermediate layer 13 is realized by the underlayer, there is no substantial increase in material cost or an increase in manufacturing steps, and the above-described useful effects can be ensured.

"use"

Laminate 10 of the second embodiment and laminate of the first embodiment Similarly, for example, it can be incorporated in the polarizing plate 20 (see FIG. 6), the liquid crystal display panel 30 (see FIG. 7), the image display device 40 (see FIG. 8), the touch panel sensor 50 (refer to FIG. 9), and the touch. The panel device 55 (see Fig. 9) is used. Other uses, such as laminate 10, can be used to avoid various uses of interference fringes. For example, the laminate 10 can be used as a window material of a machine display unit such as a timepiece or a measurement meter.

[Examples]

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

"First Embodiment"

First, the "first embodiment" of the first embodiment described above will be described.

<Modulation of composition for functional layer>

The composition for the functional layer was obtained by blending each component with the composition shown below.

(Composition layer composition 1)

Dipentaerythritol hexaacrylate (DPHA) (manufactured by Nippon Kayaku Co., Ltd.): 100 parts by mass

Polymerization initiator (product name "Irgacure 184", manufactured by BASF Japan): 5 parts by mass

Polyether modified polyfluorene (product name "TSF4460", Momentive Performance Materials Co., Ltd.): 0.025 parts by mass

Toluene: 120 parts by mass

Methyl isobutyl ketone (MIBK): 60 parts by mass

The individual refractive index of the cured coating film formed by the functional layer composition 1 having the above composition was measured and found to be 1.52.

(Composition layer composition 2)

Dipentaerythritol hexaacrylate (DPHA) (manufactured by Nippon Kayaku Co., Ltd.): 100 parts by mass

Titanium oxide microparticles (product name "TTO51 (C), Ishihara Sangyo): 30 parts by mass

Dispersing agent (product name DISPERBYK 163, manufactured by BYK-Chemie. Japan): 5 parts by mass

Polymerization initiator (product name "Irgacure 184", manufactured by BASF Japan): 5 parts by mass

Polyether modified polyfluorene (product name "TSF4460", manufactured by Momentive Performance Materials): 0.025 parts by mass

Methyl isobutyl ketone (MIBK): 220 parts by mass

The individual refractive index of the cured coating film formed by the functional layer composition 1 having the above composition was measured and found to be 1.75.

<Modulation of composition for intermediate layer>

The composition for the intermediate layer was obtained by blending the components as shown below.

(Composition for intermediate layer 1)

Aqueous dispersion of polyester resin (solid content 60%): 28.0 parts by mass

Water: 72.0 parts by mass

The individual refractive index of the cured coating film formed by the composition 1 for an intermediate layer having the above composition was measured and found to be 1.57.

(Composition 2 for the intermediate layer)

Aqueous dispersion of polyester resin (solid content 60%): 20 parts by mass

Aqueous dispersion of titanium oxide microparticles (solid content 20%): 10 parts by mass

Water: 70 parts by mass

The individual refractive index of the cured coating film formed by the composition for an intermediate layer of the above composition was measured and found to be 1.70.

(Example 1)

The molten polyethylene terephthalate was melted at 290 ° C, formed into a mold by a film, extruded into a film form, and sealed on a rotary quench drum cooled by water cooling to prepare an unstretched film. This 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 3.5 times at 120 ° C, and then the intermediate layer composition 1 was uniformly coated using a roll coater. Coated on both sides. Then, the coated film was dried at 95 ° C, and stretched at a stretching ratio of 1.5 times in a direction 90 ° from the extending direction thereof to obtain a retardation = 4800 nm, a film thickness = 80 μm, n _1x = 1.68, n _1y = 1.62, and an average value. A polyester substrate having a refractive index of 1.65. Further, the film thickness of the intermediate layer was 90 nm.

Then, on the intermediate layer after the formation, the functional layer composition 1 was applied using a bar coater, and dried at 70 ° C for 1 minute to remove the solvent to form a coating film. Then, the coating film was irradiated with ultraviolet rays at an irradiation amount of 150 mJ/cm ^{2 to} form a functional layer having a film thickness of 6.0 μm after drying and curing, and was produced by using an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd.). Laminated body.

(Example 2)

The laminate of Example 2 was produced in the same manner as in Example 1 except that the film thickness of the intermediate layer was changed to 67 nm.

(Example 3)

The laminate of Example 3 was produced in the same manner as in Example 1 except that the film thickness of the intermediate layer was changed to 115 nm.

(Example 4)

The laminate of Example 4 was produced in the same manner as in Example 1 except that the intermediate layer composition 2 was used instead of the intermediate layer composition 1 and the functional layer composition 2 was used instead of the functional layer composition 1. The film thickness of the intermediate layer was 80 nm.

(Example 5)

The laminate of Example 5 was produced in the same manner as in Example 4 except that the film thickness of the intermediate layer was set to 62 nm.

(Example 6)

The laminate of Example 6 was produced in the same manner as in Example 4 except that the film thickness of the intermediate layer was set to 105 nm.

(Comparative Example 1)

A laminate of Comparative Example 1 was produced in the same manner as in Example 1 except that the film thickness of the intermediate layer was set to 30 nm.

(Comparative Example 2)

A laminate of Comparative Example 2 was produced in the same manner as in Example 1 except that the film thickness of the intermediate layer was set to 140 nm.

(Comparative Example 3)

A laminate of Comparative Example 3 was produced in the same manner as in Example 4 except that the film thickness of the intermediate layer was set to 30 nm.

(Comparative Example 4)

A laminate of Comparative Example 4 was produced in the same manner as in Example 4 except that the film thickness of the intermediate layer was changed to 140 nm.

(Evaluation of interference fringes)

The presence or absence of interference fringes was evaluated on the basis of the following criteria. The sample is coated with black ink on the opposite side of the coated surface, and the three-wavelength fluorescent lamp is illuminated. The coated surface was shot and evaluated by observing the reflection. The evaluation criteria are as shown in Table 1, as shown in Table 1.

A: Attention was observed, but the occurrence of interference fringes was not confirmed.

B: When observing the observation, a very slight interference fringe which is not problematic in actual use is observed.

C: Interference fringes were clearly observed.

"Second embodiment"

First, the "second embodiment" of the second embodiment will be described.

<Modulation of composition for functional layer>

The composition for the functional layer was obtained by blending each component with the composition shown below.

(Composition layer composition 3)

Dipentaerythritol hexaacrylate (DPHA) (manufactured by Nippon Kayaku Co., Ltd.): 35 parts by mass

Hard coating composition containing zirconia fine particles (product name "DeSolite Z7404", manufactured by JSR): 110 mass parts

Polymerization initiator (product name "Irgacure 184", manufactured by BASF Japan): 5 parts by mass

Polyether modified polyfluorene (product name "TSF4460", manufactured by Momentive Performance Materials): 0.025 parts by mass

Toluene: 100 parts by mass

Methyl isobutyl ketone (MIBK): 40 parts by mass

The individual refractive index of the cured coating film formed by the functional layer composition 3 having the above composition was measured, and 1.65 was measured.

<Modulation of composition for intermediate layer>

The composition for the intermediate layer was obtained by blending the components as shown below.

(Composition for intermediate layer 3)

Aqueous dispersion of polyester resin (solid content 60%): 28.0 parts by mass

Water: 72.0 parts by mass

The individual refractive index of the cured coating film formed by the composition 3 for the intermediate layer of the above composition was measured and found to be 1.57.

(Composition 4 for the intermediate layer)

Aqueous dispersion of polyester resin (solid content 60%): 20 parts by mass

Aqueous dispersion of titanium oxide microparticles (solid content 20%): 10 parts by mass

Water: 70 parts by mass

The individual refractive index of the cured coating film formed by the composition 4 for the intermediate layer of the above composition was measured, and 1.70 was measured.

(Example 7)

The molten polyethylene terephthalate was melted at 290 ° C, formed into a mold by a film, extruded into a film form, and sealed on a rotary quench drum cooled by water cooling to prepare 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 3.5 times at 120 ° C, and then the intermediate layer composition 3 was uniformly coated using a roll coater. Coated on both sides. Then, the coated film was dried at 95 ° C, and stretched at a stretching ratio of 1.5 times in a direction 90 ° from the extending direction thereof to obtain a retardation = 4800 nm, a film thickness = 80 μm, n _1x = 1.68, n _1y = 1.62, and an average value. A polyester substrate having a refractive index of 1.65. Further, the film thickness of the intermediate layer was 20 nm.

Then, on the intermediate layer after the formation, the functional layer composition 3 was applied using a bar coater, and dried at 70 ° C for 1 minute to remove the solvent to form a coating film. Then, the coating film was irradiated with ultraviolet rays at an irradiation amount of 150 mJ/cm ^{2 to} form a functional layer having a film thickness of 6.0 μm after drying and curing, and was produced by using an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd.). Laminated body.

(Example 8)

The laminate of Example 8 was produced in the same manner as in Example 7 except that the film thickness of the intermediate layer was set to 30 nm.

(Example 9)

The laminate of Example 9 was produced in the same manner as in Example 7 except that the film thickness of the intermediate layer was changed to 40 nm.

(Embodiment 10)

The laminate of Example 10 was produced in the same manner as in Example 7 except that the intermediate layer composition 4 was used instead of the intermediate layer composition 3. The film thickness of the intermediate layer was 18 nm.

(Example 11)

The laminate of Example 11 was produced in the same manner as in Example 10 except that the film thickness of the intermediate layer was set to 30 nm.

(Embodiment 12)

The laminate of Example 12 was produced in the same manner as in Example 10 except that the film thickness of the intermediate layer was set to 35 nm.

(Comparative Example 5)

The same as Example 7 except that the film thickness of the intermediate layer was set to 70 nm. The laminate of Comparative Example 5 was produced.

(Comparative Example 6)

A laminate of Comparative Example 6 was produced in the same manner as in Example 10 except that the film thickness of the intermediate layer was changed to 70 nm.

(Evaluation of interference fringes)

The presence or absence of interference fringes was evaluated on the basis of the following criteria. The sample was coated with a black ink on the opposite side of the coated surface, and a three-wavelength fluorescent lamp was irradiated onto the coated surface to evaluate the reflection. The evaluation criteria are as shown in Table 2 below.

A: Attention was observed, but the occurrence of interference fringes was not confirmed.

B: When observing the observation, a very slight interference fringe which is not problematic in actual use is observed.

C: Interference fringes were clearly observed.

Claims (18)

A laminate comprising: an optical transparency substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and adjacent to the intermediate layer the opposite side of the light-transmitting substrate, the functional layer is laminated to the intermediate layer; average refractive index of the surface of the transparent substrate of n _1, in-plane average refractive index of the intermediate layer is n _2, and The average refractive index n _{3 in} the plane of the aforementioned functional layer satisfies n ₁ <n ₂ <n ₃ ... condition (a) n ₁ >n ₂ >n ₃ ... condition (a) and condition (b) Any one of the thickness t [nm] of the intermediate layer, the shortest wavelength λ _min [nm] of visible light, and the wavelength λ _ave [nm] between the longest wavelength λ _max [nm] of visible light, and the intermediate layer The in-plane average refractive index n ₂ satisfies the condition (c1) of λ _ave /(6×n ₂ )<t<λ _ave /(3×n ₂ )...condition (c1), wherein the light-transmitting substrate direction having a birefringence within the plane, the inner surface of the transparent substrate in the maximum refractive index of the refractive index in the slow axis direction i.e., n _1x, extending parallel with the direction of the slow axis of the transparent substrate N _2x, the refractive index of the functional layer parallel to a direction of the slow axis and the direction of the light-transmitting substrate in the n _3x satisfies _{n 1x <n 2x <n 3x} ... conditions (the refractive index of the intermediate layer f) n _1x >n _2x >n _3x ... the condition (f) and (g) formed by the condition (g) is in the fast axis direction orthogonal to the slow axis direction of the light-transmitting substrate a refractive index n _1y , a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate, and a direction parallel to the fast axis direction of the light-transmitting substrate The refractive index n _{3y of the} above functional layer satisfies n _1y <n _2y <n _3y ... condition (h) n _1y >n _2y >n _3y ... condition (i) is any one of conditions (h) and (i) The intermediate layer has in-plane birefringence, a refractive index n _{2x of the} intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate, and the aforementioned fast axis of the light-transmitting substrate the refractive index of the intermediate layer in a direction parallel to the direction of the n _2y satisfies n _2x> n _2y relationship formed between the refractive index of the transparent substrate of the slow axis direction of the n _1x, through the The index of refraction of the substrate in the fast axis direction n _1y, and the direction parallel to the direction of the slow axis of the transparent substrate of the intermediate layer of n _2x, and the light-transmitting substrate and the The refractive index n _{2y of the} intermediate layer in the direction in which the fast axis directions are parallel satisfies the relationship of (n _{1x -} n _1y ) > (n _{2x -} n _2y ). A laminate comprising: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and a light-transmitting group adjacent to the intermediate layer On the opposite side of the material, a functional layer laminated on the intermediate layer; an average refractive index n _{1 in} the plane of the light-transmitting substrate; an average refractive index n _{2 in} the plane of the intermediate layer; and the functional layer The in-plane average refractive index n ₃ satisfies n ₁ <n ₂ <n ₃ ... Condition (a) n ₁ >n ₂ >n ₃ ... Condition (b) Any of the conditions (a) and (b) The thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy the condition (c2) formed by the condition (c2) of 110/n ₂ ≦t ≦ 170 / n ₂ , The light-transmitting substrate has in-plane birefringence, and a direction of a maximum refractive index in a plane of the light-transmitting substrate, that is, a refractive index n _1x in a slow axis direction, and the light-transmitting substrate the refractive index of the refractive functional layer parallel to the direction of the slow axis direction of the intermediate layer in the n _2x, and the direction parallel to the direction of the slow axis of the transparent substrate of satisfy any n _{3x n 1x <n 2x <n 3x} ... condition _{(f) n 1x> n 2x} > n 3x ... conditions (g) to the conditions of (f) and (g) of a person, and the light-transmitting a refractive index n _1y in a fast axis direction orthogonal to the slow axis direction of the substrate, a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light transmitting substrate, and The refractive index n _{3y of the} functional layer in the direction in which the fast axis direction of the optical substrate is parallel satisfies n _1y <n _2y <n _3y ... condition (h) n _1y >n _2y >n _3y ... condition (i) In any one of the conditions (h) and (i), the intermediate layer has in-plane birefringence, and a refractive index n of the intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate _2x and a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate satisfying a relationship of n _2x >n _2y , the slow axis direction of the light-transmitting substrate in the refractive index n _1x, the refractive index of the transparent substrate of the fast axis direction in the n _1y, and the intermediate direction parallel to the direction of the slow axis of the transparent substrate of the layers Reflectance n _2x, the refractive index of the direction parallel with the light-transmitting substrate and the fast axis direction of the intermediate layer satisfies n _{2y (n 1x -n 1y)> (} n 2x -n 2y) formed by relationship. A laminate comprising: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and a light-transmitting group adjacent to the intermediate layer On the opposite side of the material, a functional layer laminated on the intermediate layer; an average refractive index n _{1 in} the plane of the light-transmitting substrate; an average refractive index n _{2 in} the plane of the intermediate layer; and the functional layer The in-plane average refractive index n ₃ satisfies n ₁ <n ₂ <n ₃ ... Condition (a) n ₁ >n ₂ >n ₃ ... Condition (b) Any of the conditions (a) and (b) The thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 555 / (6 × n ₂ ) < t < 555 / (3 × n ₂ ) ... condition (c3) The condition (c3), wherein the light-transmitting substrate has in-plane birefringence, and the direction of the maximum refractive index in the in-plane of the light-transmitting substrate, that is, the refractive index n _1x in the slow axis direction direction parallel to a direction parallel to the refractive index of the transparent substrate and the slow axis direction of the intermediate layer of n _2x, and the transparent substrate and the slow axis direction of the functional layer Reflectance n _3x satisfies _{n 1x <n 2x <n 3x} ... condition _{(f) n 1x> n 2x} > any n _3x ... conditions (g) as to the conditions of (f) and (g) of a person, and the lens a refractive index n _1y in a fast axis direction orthogonal to the slow axis direction of the optical substrate, and a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light transmitting substrate, and The refractive index n _{3y of the} functional layer in the direction in which the fast axis direction of the light-transmitting substrate is parallel satisfies n _1y <n _2y <n _3y ... condition (h) n _1y >n _2y >n _3y ... condition (i Any one of the conditions (h) and (i), wherein the intermediate layer has in-plane birefringence, and the intermediate layer is refracted in a direction parallel to the slow axis direction of the light-transmitting substrate a ratio n _2x and a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate satisfy a relationship of n _2x >n _2y , and the slowness of the light-transmitting substrate refractive index axis direction of the intermediate n _1x, the refractive index of the transparent substrate of the fast axis direction in the n _1y, and the direction parallel to the direction of the slow axis of the transparent substrate of the Between the refractive index n _2x, and the direction parallel to the light-transmitting substrate and the fast axis direction of the intermediate layer satisfies n _{2y (n 1x -n 1y)> (} n 2x -n 2y) into the Relationship. A laminate comprising: a light-transmitting substrate; an intermediate layer laminated on the light-transmitting substrate adjacent to the light-transmitting substrate; and a light-transmitting group adjacent to the intermediate layer On the opposite side of the material, a functional layer laminated on the intermediate layer; an average refractive index n _{1 in} the plane of the light-transmitting substrate; an average refractive index n _{2 in} the plane of the intermediate layer; and the functional layer The in-plane average refractive index n ₃ satisfies n ₁ <n ₂ <n ₃ ... Condition (a) n ₁ >n ₂ >n ₃ ... Condition (b) Any of the conditions (a) and (b) The thickness t [nm] of the intermediate layer and the average refractive index n _{2 in} the plane of the intermediate layer satisfy 507 / (6 × n ₂ ) < t < 507 / (3 × n ₂ ) ... condition (c4) The condition (c4), wherein the light-transmitting substrate has in-plane birefringence, and the direction of the maximum refractive index in the in-plane of the light-transmitting substrate, that is, the refractive index n _1x in the slow axis direction direction parallel to a direction parallel to the refractive index of the transparent substrate and the slow axis direction of the intermediate layer of n _2x, and the transparent substrate and the slow axis direction of the functional layer Reflectance n _3x satisfies _{n 1x <n 2x <n 3x} ... condition _{(f) n 1x> n 2x} > any n _3x ... conditions (g) as to the conditions of (f) and (g) of a person, and the lens a refractive index n _1y in a fast axis direction orthogonal to the slow axis direction of the optical substrate, and a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light transmitting substrate, and The refractive index n _{3y of the} functional layer in the direction in which the fast axis direction of the light-transmitting substrate is parallel satisfies n _1y <n _2y <n _3y ... condition (h) n _1y >n _2y >n _3y ... condition (i Any one of the conditions (h) and (i), wherein the intermediate layer has in-plane birefringence, and the intermediate layer is refracted in a direction parallel to the slow axis direction of the light-transmitting substrate a ratio n _2x and a refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate satisfy a relationship of n _2x >n _2y , and the slowness of the light-transmitting substrate a refractive index n _1x in the axial direction, a refractive index n _1y in the fast axis direction of the light-transmitting substrate, and the intermediate layer in a direction parallel to the slow axis direction of the light-transmitting substrate The refractive index n _2x and the refractive index n _{2y of the} intermediate layer in a direction parallel to the fast axis direction of the light-transmitting substrate satisfy (n _1x -n _1y )>(n _2x -n _2y ) Relationship. The laminate according to any one of claims 1 to 4, wherein the light-transmitting substrate has in-plane birefringence, and the maximum refractive index in the plane of the light-transmitting substrate The direction, that is, the refractive index n _1x in the slow axis direction, the refractive index n _1y in the fast axis direction orthogonal to the slow axis direction of the light transmissive substrate, and the intermediate layer The average refractive index n ₂ in the plane and the average refractive index n _{3 in} the plane of the functional layer satisfy n _1x <n ₂ <n ₃ ... condition (d) n _1y >n ₂ >n ₃ ... condition (e) Any of the conditions (d) and (e). The laminate according to claim 5, wherein the intermediate layer has in-plane birefringence, and when the laminate is observed in a normal direction, the slow axis direction of the light-transmitting substrate and the surface of the intermediate layer The direction of the maximum refractive index in the inner middle, that is, the angle formed by the slow axis direction of the intermediate layer is less than 30°. The laminate of claim 5, wherein the intermediate layer has in-plane birefringence, and the slow axis direction of the light-transmitting substrate is a direction of a maximum refractive index in a plane of the intermediate layer, That is, the slow axis directions of the intermediate layers are parallel. The laminate according to claim 5, wherein the intermediate layer has in-plane birefringence, a refractive index n _1x in the slow axis direction of the light-transmitting substrate, and the aforementioned light-transmitting substrate a refractive index n _1y in the axial direction, a direction of a maximum refractive index in the in-plane of the intermediate layer, that is, a refractive index n _2a in a slow axis direction of the intermediate layer, and an orthogonal to the slow axis direction of the intermediate layer The refractive index n _2b in the fast axis direction of the intermediate layer satisfies the relationship of (n _{1x -} n _1y ) > (n _{2a -} n _2b ). The laminate according to any one of claims 1 to 4, wherein the light-transmitting substrate has in-plane birefringence, and the retardation of the light-transmitting substrate is 3,000 nm or more. Such as the laminate of claim 9 of the patent scope, wherein the aforementioned light transmission The substrate is a polyester substrate. The laminate according to any one of claims 1 to 4, wherein the functional layer is a hard coat layer. The laminate according to any one of claims 1 to 4, further comprising a second functional layer provided on the side opposite to the intermediate layer side of the functional layer. The laminate of claim 12, 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 laminate according to any one of claims 1 to 4. A liquid crystal display panel characterized by comprising the laminate according to any one of claims 1 to 4. An image display device comprising the laminate according to any one of claims 1 to 4. A touch panel sensor, characterized by the laminate of any one of claims 1 to 4, and a sensor electrode bonded to the laminate. A touch panel device characterized by having a touch panel sensor as claimed in claim 17 of the patent application.