KR101947838B1 - Laminated base material, laminated body, polarizing plate, liquid crystal display panel, and image display device - Google Patents

Abstract

인 관계를 만족한다.Provided is a laminated base material which includes a light-transmitting base material having in-plane birefringence and makes interference fringes inconspicuous.
The functional layer 15 is formed on one side of the laminated substrate 11. The laminated substrate includes a light-transmitting base material 12 having in-plane birefringence and a refractive-index adjusting layer 13 laminated with the light-transmitting base material and having in-plane birefringence. The refractive index adjustment layer is positioned between the light-transmitting substrate and the functional layer. The refractive index n _1x in the slow axis direction dx in the plane of the light-transmitting substrate, the refractive index n _2x of the refractive index adjusting layer in the slow axis direction dx, the refractive index n _3x of the function layer in the slow axis direction dx, refractive index at dy n _1y, n _3y are refractive indices of the functional layer in the refractive index n _2y and the fast axis direction of the refractive index adjusting layer dy in the fast axis direction dy

Lt; / RTI >

Description

TECHNICAL FIELD [0001] The present invention relates to a laminated substrate, a laminated body, a polarizing plate, a liquid crystal display panel, and an image display device,

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

On an image display surface of an image display device such as a liquid crystal display, a cathode ray tube display (CRT), a plasma display, an electroluminescence display (ELD), and a field emission display (FED) For example, a touch panel sensor), there is provided a laminate having a functional layer expected to exhibit a desired function. As a typical functional layer, a hard coat layer for the purpose of improving scratch resistance is exemplified.

As the light-transmitting base material of the laminate supporting the functional layer, a film made of optically isotropic film having no birefringence, typically cellulose ester represented by triacetyl cellulose is used. When a film having birefringence is applied to a display surface of a display device using polarized light such as a liquid crystal display device, problems such as the appearance of unevenness in color (hereinafter also referred to as " rainbow unevenness " It is because it throws away. However, the cellulose ester film is disadvantageous in that it is inferior in humidity resistance and heat resistance, and that the polarizing plate functions, such as polarizing function and color, is lowered when used under high temperature and high humidity.

From the problems of such a cellulose ester film, it has been desired to use a general-purpose film that can be easily obtained on the market or can be produced by a simple method as a light-transmitting substrate of a laminate, and various studies have been made. For example, in JP2011-107198A, a white light emitting diode is used as a light source, and a polymer film having retardation of 3000 nm to 30000 nm is arranged so that the angle formed by the absorption axis of the polarizing plate and the slow axis of the polymer film is 45 degrees It has been reported that when a screen is viewed through a polarizing plate such as a sunglass, good visibility can be ensured irrespective of an observation angle.

However, when a hard coat layer is formed on a polyester film or a polycarbonate film, which is a preferable polymer film in JP2011-107198A, it is possible to suppress the occurrence of irregularity of iridescence. However, as another problem, . Here, the interference fringe pattern is a phenomenon in which light reflected at the surface of the functional layer and partial iris color appear due to interference of the light incident on the functional layer and reflected at the interface between the functional layer and the light-transmitting substrate, Is a phenomenon that occurs because the wavelengths that are strengthened with each other are changed. This phenomenon is not only difficult for the user to see but also gives an unpleasant impression, and improvement is strongly demanded.

As countermeasures against interference streaking, it is conceivable that the refractive index difference between the functional layer and the light-transmitting substrate is reduced to lower the reflectance at the interface between the functional layer and the light-transmitting substrate. However, when the light-transmitting base material has in-plane birefringence and its retardation value is high, in order to avoid the thickness of the light-transmitting base material from becoming thick from the viewpoint of cost, etc., It is necessary to increase the refractive index difference between the refractive index in the axial direction and the refractive index in the fast axis direction. Therefore, it is difficult to reduce the refractive index difference between the functional layer and the light-transmitting substrate in both of the direction of the slow axis and the direction of the fast axis, and as a result, the interference fringe can not be sufficiently conspicuous.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to make interference fringes less conspicuous while using a light-transmitting base material having in-plane birefringence.

In the laminated substrate according to the present invention,

A multilayer substrate comprising a functional layer formed on one side thereof to form a laminate,

A light-transmitting substrate having in-plane birefringence,

And a refractive index adjustment layer laminated with the light-transmitting base material and having in-plane birefringence, the refractive index adjustment layer being positioned between the light-transparent base and the functional layer,

The refractive index n _1x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmitting base material and the refractive index n _2x of the refractive index adjusting layer in the direction of the slow axis, The refractive index n _3x of the functional layer in a direction parallel to the slow axis direction of the light-transmitting substrate is

Lt; RTI ID = 0.0 >

A refractive index n _{1y in the} direction of the fast axis perpendicular to the slow axis direction of the light-transmitting substrate, a refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light- The refractive index _n3y of the functional layer in the direction parallel to the fast axis direction of the substrate is

Lt; / RTI >

In the laminated base material according to the present invention, the refractive index n _2x of the refractive index-adjusting layer in the direction parallel to the slow axis direction of the light-transmitting base material and the refractive index n _2x of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light- When the refractive index n _2y of the refractive index adjusting layer is

May be satisfied.

In the laminated base material according to the present invention, it is preferable that a refractive index n _1x in the slow axis direction of the light-transmitting substrate, a refractive index n _1y in the fast axis direction of the light- and a refractive index of the refractive index adjustment layer in the direction parallel to n _2x and _2y refractive index n of the refractive index adjustment layer in a direction parallel to the fast axis direction of the light-transmitting substrate is

May be satisfied.

In the laminated base material according to the present invention, when the laminated base material is observed from the normal direction, the direction of the slow axis of the light-transmitting base material and the direction of the refractive index adjustment which is the direction with the greatest refractive index in the plane of the refractive- The angle formed by the slow axis direction of the layer may be less than 45 degrees.

In the laminated substrate according to the present invention, the slow axis direction of the light-transmitting substrate may be parallel to the slow axis direction of the refractive index adjustment layer, which is the direction in which the refractive index is the greatest in the surface of the refractive index adjustment layer.

In the laminated substrate according to the present invention, the refractive index n _1x of the light-transmitting substrate in the slow axis direction, the refractive index n _1y in the fast axis direction of the light-transmitting substrate, The refractive index n _2a of the refractive index adjusting layer in the direction of the greatest refractive index in the slow axis direction and the refractive index n _2b of the refractive index adjusting layer in the fast axis direction of the refractive index adjusting layer perpendicular to the slow axis direction are

May be satisfied.

In the laminated base material according to the present invention,

The refractive index n _1x of the refractive index adjusting layer in a direction parallel to the slow axis direction dx of the light transmitting substrate and the refractive index n _2x of the refractive index adjusting layer of the light transmitting substrate, The refractive index n _3x of the functional layer in the direction parallel to the axial direction is

Lt; RTI ID = 0.0 >

The refractive index n _1y of the light-transmitting substrate in the fast axis direction, the refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light-transmitting substrate, and the refractive index n _2y of the light- The refractive index n _3y of the functional layer in a direction parallel to

May be satisfied.

The laminated substrate according to the present invention may have retardation of 3000 nm or more.

In the laminated base material according to the present invention, the light-transmitting base material may have retardation of 3000 nm or more.

In the laminate according to the present invention,

Any one of the above-described laminated substrates according to the present invention,

And a functional layer formed on one side of the laminated substrate,

And the refractive index adjusting layer is positioned between the light-transmitting substrate and the functional layer.

In the laminate according to the present invention, the functional layer may be a hard coat layer.

The laminated body according to the present invention may further comprise a second functional layer provided on the side of the functional layer opposite to the side of the laminated substrate. In the laminate according to 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.

In the polarizing plate according to the present invention,

A polarizing element,

Any one of the above-described laminated substrates according to the present invention, or any of the above-described laminated bodies according to the present invention.

The polarizing plate according to the present invention comprises any one of the laminated substrates according to the present invention described above, the laminate according to the present invention described above, or the polarizing plate according to the present invention described above.

The image display apparatus according to the present invention comprises any one of the above-described laminated substrates according to the present invention, the laminate according to the present invention described above, or the above-mentioned polarizing plate according to the present invention.

The touch panel device according to the present invention may be any one of the touch panel sensor and the above-described laminated substrate according to the present invention provided on the touch panel sensor, the laminate according to the present invention described above, And a polarizing plate according to the present invention.

According to the present invention, a refractive index control layer having in-plane birefringence is provided between a functional layer and a light-transmitting base material having in-plane birefringence. With this refractive index control layer, it is possible to reduce the reflectance of the light which has once entered the functional layer. Thereby, the interference fringe can be made inconspicuous.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining an embodiment of the present invention, showing a layer structure of a laminate. Fig.
Fig. 2 is a view corresponding to Fig. 1, in which the functional layer is a layer structure of another example. Fig.
Fig. 3 is a view for explaining the distribution of the refractive index in the laminate shown in Fig. 1, and is a perspective view schematically showing the laminate. Fig.
Fig. 4 is a view for explaining the in-plane birefringence in the laminated substrate shown in Fig. 1, and is a plan view schematically showing a laminated substrate. Fig.
Fig. 5 is a view showing a schematic configuration of a polarizing plate including the laminate shown in Fig. 1; Fig.
6 is a view showing a schematic configuration of a liquid crystal display panel including the laminate shown in Fig.
7 is a view showing a schematic configuration of a display device including the laminate shown in Fig.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, in the drawings attached to the present specification, dimensions and aspect ratios are appropriately changed and exaggerated from the real world for convenience in order to facilitate understanding and understanding. 1 to 7 are views for explaining an embodiment of the present invention. 1 and 2 are views for explaining a laminated base material and a laminated body. Figs. 3 and 4 are views for explaining the distribution of the refractive indexes of the laminated base material and the laminate. Fig. Figs. 5 to 7 are schematic diagrams showing the configurations of a polarizing plate, a liquid crystal display panel, and a laminate.

&Quot; Laminated substrate and laminate "

≪ Overall structure of laminated base material and laminate >

First, the overall structure of the laminated base material 11 and the laminated body 10 will be described. As shown in Fig. 1, the laminate 10 has a laminate substrate 11 and a functional layer 15 formed on one side of the laminate substrate 11. As shown in Fig. The laminated substrate 11 has a light-transmitting base material 12 and a refractive index adjusting layer 13 laminated with the light-transmitting base material 12. [ In the laminate 10, the refractive index adjusting layer 13 is located between the light-transmitting base material 12 and the functional layer 15. That is, the functional layer 15 is laminated on the laminate substrate 11 from the refractive index adjusting layer 13 side. In the illustrated example, the refractive index adjusting layer 13 is formed on one surface of the light-transmitting base material 12 in the laminated substrate 11. [ That is, the laminate 10 is configured to include three layers of the transparent base material 12, the refractive index adjusting layer 13, and the functional layer 15 in this order. The refractive index adjusting layer 13 is made of a transparent material Is disposed adjacent to the base material 12 and the functional layer 15 to form an interface between the light-transparent base material 12 and the functional layer 15, respectively.

2 shows a laminate as one modified example of the laminate 10 shown in Fig. 2 is that the second functional layer 17 is formed on the surface of the functional layer 15 that is not facing the laminated substrate 11, (10). In the laminate 10 shown in Fig. 1, the functional layer 15 may be constituted by a hard coat layer formed on one side of the laminate substrate 11. Fig. On the other hand, in the laminate 10 shown in Fig. 2, the functional layer 15 is formed of a hard coat layer formed on one side of the laminated substrate 11, and the second functional layer 17 is formed of a hard coat layer And a low refractive index layer formed on the surface opposite to the laminated substrate 11.

The light-transmitting base material 12 included in the laminated base material 11 is optically anisotropic and has at least in-plane birefringence. The refractive index adjusting layer 13 included in the laminated base material 11 is also optically anisotropic and has at least in-plane birefringence. Therefore, as shown in Figs. 3 and 4, the refractive index of the light-transparent base material 12 in the two orthogonal directions along the sheet surface of the sheet-like light-transparent base material 12 is different. Similarly, the refractive index of the refractive index adjusting layer 13 in the two orthogonal directions along the sheet surface of the sheet-shaped refractive index adjusting layer 13 is different.

Here, the " sheet surface (film surface, sheet surface) " means a sheet surface in which the sheet-like (film, plate) Point to the face. The sheet surface of the refractive index adjusting layer 13, the sheet surface of the functional layer 15, the sheet surface of the laminated substrate 11, and the sheet surface of the laminate substrate 11, The sheet surfaces of the sheet member 10 are parallel to each other.

Whether or not the light transmitting base material 12 and the refractive index adjusting layer 13 have in-plane birefringence can be determined by measuring the refractive index of the light transmitting base material 12 or the refractive index adjusting layer 13 within the surface of the light transmitting base material 12 or the refractive index adjusting layer 13 (The maximum value of the refractive index difference in the two directions along the sheet surface)

Is satisfied or not. That is, when the maximum refractive index difference? N in the plane of the light-transmitting base material 12 is 0.0005 or more, the light-transmitting base material 12 has birefringence, and the maximum refractive index When the difference DELTA n is less than 0.0005, it is judged that the light-transparent base material 12 does not have birefringence. Similarly, when the maximum refractive index difference DELTA n in the surface of the refractive index adjusting layer 13 is 0.0005 or more, the refractive index adjusting layer 13 has birefringence and the maximum refractive index If the difference DELTA n is less than 0.0005, it is determined that the refractive index adjustment layer 13 does not have birefringence. The birefringence index can be measured by using KOBRA-WR manufactured by Isabuchi Kogyo Co., Ltd. with a measurement angle of 0 ° and a measurement wavelength of 552.1 nm. At this time, the film thickness and the average refractive index are required for the calculation of the birefringence. The film thickness can be measured by using a micrometer (manufactured by Mitsutoyo Corporation) or an electric micrometer (manufactured by Anritsu Co., Ltd.) for the light-transmitting film, for example. When the refractive index adjustment layer 13 is formed as a thin film layer, the TEM cross section is observed, and the height of the target layer is measured at least 10 points, and the average value is obtained as the film thickness. The average refractive index can be measured by using an Abbe's refractive index meter (NAR-4T manufactured by Atago) or an " ellipsometer " manufactured by Nippon Bunko Co.,

The maximum refractive index difference? N in the plane of TD80UL-M (manufactured by Fuji Film), which is generally made of triacetyl cellulose, and ZF16-100 (manufactured by Nippon Zeon Co., Ltd.), which is a cycloolefin polymer, Of 0.0000375 and 0.00005, respectively, and it is judged that it has no birefringence (isotropic).

In the laminate 10 described herein, the refractive index n _1x in the slow axis direction dx, which is the direction with the greatest refractive index in the plane of the light-transmitting substrate 12, and the refractive index nx of the slow axis direction dx of the light- The refractive index n _2x of the refractive index adjusting layer in the parallel direction and the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction dx of the light transmitting base material 12

(A) is satisfied. In addition, the refractive index n _1y in the fast axis direction dy orthogonal to the slow axis direction dx in the plane of the light-transmitting base material 12, the refractive index adjustment in the direction parallel to the fast axis direction dy of the light- The refractive index n _2y of the layer 13 and the refractive index n _3y of the functional layer 15 in the direction parallel to the fast axis direction dy of the light-

(B).

That is, the refractive index adjustment layer 13 is disposed between the functional layer 15 and the light-transmitting base material 12 having birefringence, and is arranged in both directions of the slow axis direction dx and the fast axis direction dy of the light- So that the refractive index is changed in two steps. As a result, there is no interface between the functional layer 15 and the light-transmitting base material 12 having birefringence, in which the refractive index in the slow axis direction dx of the light-transparent base material 12 largely changes, There is no interface at which the refractive index in the fast axis direction dy of the substrate 12 largely changes. That is, between the functional layer 15 and the light-transmitting base material 12 having birefringence, the refractive index difference in both the slow axis direction dx and the fast axis direction dy of the light-transparent base material 12 is small, There is only a lower interface.

Therefore, it is possible to effectively prevent the traveling direction from returning due to reflection while the light incident on the multilayer body 10 from the functional layer 15 side advances toward the light-transparent base material 12. [ The light reflected from the surface of the functional layer 15 and the light reflected from the surface of the functional layer 15 and the refractive index adjusting layer 13 or the refractive index of the refractive index adjusting layer 13 out of the light incident on the layered body 10 from the side of the functional layer 15 The interference fringes that can be generated by the light reflected at the interface between the adjustment layer 13 and the light-transmitting base material 12 can be effectively suppressed.

The refractive index n _2x of the refractive index adjusting layer 13 in the direction parallel to the slow axis direction dx of the light-transmitting base material 12 and the refractive index n _2x in the direction parallel to the fast axis direction dy of the light- When the refractive index n _2y of the adjustment layer 13 is

(C). ≪ / RTI > In this case, the refractive index in the slow axis direction dx of the light-transparent base material 12 can be changed little by little between the functional layer 15 and the light-transmitting base material 12 having birefringence, The refractive index in the fast axis direction dy of the light-transmitting base material 12 can be changed little by little in two steps. This makes it possible to more effectively prevent the traveling direction from being reflected back by the reflection while the light incident on the laminate 10 from the functional layer 15 side proceeds to the light-transparent base material 12. [ As a result, interference fringes can be made more inconspicuous.

When the condition (c) is satisfied, the refractive index n _1x in the slow axis direction dx of the light-transparent substrate 12, the refractive index n _1y in the fast axis direction dy of the light-transparent substrate 12, The refractive index adjusting layer 13 in the direction parallel to the slow axis direction dx of the substrate 12 in the direction parallel to the fast axis direction dy of the refractive index adjusting layer 13 and the refractive index _n2x of the light- ) &_{Lt; /} RTI >

It is more preferable that the condition (d) is satisfied. For example, the refractive index n _3x of the functional layer 15 in the direction parallel to the slow axis direction dx of the light-transmitting base material 12 and the refractive index n _3x of the function layer 15 in the direction parallel to the fast axis direction dy of the light- Typically, when the refractive index n _3y of the functional layer 15 is not significantly different, typically, when the functional layer 15 is optically isotropic and does not have birefringence, the conditions (c) and (d) , The refractive index adjusting layer 13 does not exhibit strong birefringence more than necessary and the refractive index can be changed little by little in both directions in both the slow axis direction dx and the fast axis direction dy of the light- have. This makes it possible to more effectively prevent the traveling direction from being reflected back by the reflection while the light incident on the laminate 10 from the functional layer 15 side proceeds to the light-transparent base material 12. [ As a result, interference fringes can be made more inconspicuous.

4, when the laminated substrate 11 is observed from the normal direction (the direction normal to the sheet surface of the laminated substrate 11), the relationship between the slow axis direction dx of the light- And the angle da in the slow axis direction of the refractive index adjustment layer 13, which is the direction with the largest refractive index in the plane of the refractive index adjustment layer 13, is less than 45 degrees (condition (e)). . As the angle? Is smaller, the distribution of the refractive index in the plane of the refractive index adjustment layer 13 tends to be the same as the distribution of the refractive index in the plane of the light-transparent base 12. In other words, when the angle? Is less than 45 degrees, not only the two directions of the above-mentioned light-transmitting base material 12 in the slow axis direction dx and the fast axis direction dy but also in the various directions along the sheet surface of the light- Refractive index in the functional layer 15 and the light-transmitting base material 12 does not vary greatly between the functional layer 15 and the light-transparent base material 12 but gradually changes in two divided portions. In particular, when the angle? Is 0, that is, when the slow axis direction dx of the transparent base 12 and the adjustment direction da of the slow axis of the refractive index adjustment layer 13 are parallel (condition (f)), The refractive index in the functional layer 15 gradually changes between the functional layer 15 and the light-transmitting base 12 in two portions, while exhibiting the same tendency as the change in the refractive index in the other direction. Thus, it is possible to very effectively prevent the light reflected by the reflective layer 12 from returning to the traveling direction while the light incident on the laminate 10 from the side of the functional layer 15 proceeds to the light-transparent base material 12, It can be made very inconspicuous.

Here, the ellipse drawn on the light-transmitting base material 12 in FIG. 4 shows a cross-section on the light-transmitting base material 12 for an example of the refractive index ellipsoid showing the distribution of the refractive index of the light-transmitting base material 12. Similarly, the ellipse drawn on the refractive index adjusting layer 13 in FIG. 4 shows a cross section on the refractive index adjusting layer 13 for an example of the refractive index ellipsoid showing the distribution of the refractive index of the refractive index adjusting layer 13.

The refractive index n _1x in the slow axis direction dy of the light transmitting base material 13 and the refractive index n _1y in the fast axis direction dy of the refractive index adjusting layer 13 the index of refraction n _2a and a refractive index of a fast axis direction db of the adjustment layer in the refractive index n _2b in

It is preferable that the condition (g) is satisfied. When the condition (g) is satisfied, it is possible to prevent the refractive index adjusting layer 13 from having strong birefringence more than necessary, as in the case where the above-mentioned condition (d) is satisfied, .

In addition, with one or more of the aforementioned conditions (a) ~ (g), averaged refractive surface of the light-transmitting substrate _{(12) n 1 (n 1} = (n 1x + n 1y) / 2), the refractive index adjusting layer ( 13) within the average refractive index n ₂ if the _{(n 2 = (n 2x +} n 2y) / 2) and the functional layer (in the average refractive index side of _{15) n 3 (n 3 =} (n 3x + n 3y) / 2) end

It is preferable to satisfy the condition (h). When the condition (h) is satisfied, appropriate birefringence is given to the refractive index adjusting layer 13, thereby making it possible to effectively prevent interference fringes.

As a typical example, when the light-transmitting substrate 12 is formed from a biaxially stretched polyethylene terephthalate film and the functional layer 15 functions as a hardcoat layer, the light-transmitting substrate 12 may have a strong birefringence Plane average refractive index n ₁ of the light-transmitting base material 12 is larger than the in-plane average refractive index n ₃ of the functional layer 15. In this case, by satisfying the condition (h), the refractive index adjusting layer 13 can have birefringence to an appropriate degree according to the degree of birefringence of the functional layer 15, and the interference fringe can be made less effective .

The refractive index n _1x in the slow axis direction dx of the light-transparent substrate 12 and the refractive index n _{1x in} the fast axis direction dy of the light-transmitting substrate 12 together with at least one of the above conditions (a) to (h) in the refractive index n _1y, the refractive index n _2x, fast axis direction, dy, and the direction parallel to the light-transmitting substrate 12 having a refractive index adjusting layer 13 in the direction parallel with the slow axis direction dx of the light-transmitting substrate 12 The refractive index n _2y of the refractive index adjusting layer 13 in the direction parallel to the slow axis direction dx of the transparent base 12 and the refractive index n _3x of the function layer 15 in the direction parallel to the slow axis direction dx of the light- the refractive index _n3y of the functional layer 15 in the direction parallel to dy is

It is preferable that the condition (i) is satisfied. When the condition (i) is satisfied, it is possible to avoid a difference in refractive index between the refractive index adjusting layer 13 and the light-transmitting base 12 and a difference in refractive index between the refractive index adjusting layer 13 and the functional layer 15 As a result, the refractive index difference from the light-transmitting base material 12 to the functional layer 15 can be changed little by little. Thereby, the interference fringe can be effectively prevented from being conspicuous.

However, retardation Re is known as an index indicating the degree of birefringence in the plane. The retardation Re is expressed as follows using the refractive index n _{max in the} slow axis direction which is the largest value, the refractive index n _min in the fast axis direction in which the minimum value is small, and the thickness d (unit: nm).

As disclosed in JP2011-107198A, it is preferable that the laminated substrate 11 has a retardation of 3000 nm or more from the viewpoint of preventing irregularity of iridescence. Further, when the condition (d) or the condition (g) is satisfied, it is more preferable that the light-transmitting base material 12 has retardation of 3000 nm or more. The retardation can be measured, for example, by setting the measurement angle of 0 DEG and the measurement wavelength of 589.3 nm by using KOBRA-WR manufactured by Isoguchi Kikai Co., In the retardation, two polarizing plates were used to obtain the orientation axis direction (principal axis direction) of the film, and the refractive indexes (n _x , n _y ) of two axes perpendicular to the orientation axis direction were measured using Abbe's refractive index meter NAR-4T manufactured by Kojima Corporation). Here, an axis indicating a larger refractive index is defined as a slow axis. The film thickness d (nm) was measured using an electric micrometer (manufactured by Anritsu), and the unit was converted into nm. From the product of the refractive index difference (n _x -n _y ) and the thickness d (nm) of the film, the retardation can also be calculated.

From the viewpoint of setting the retardation of the light-transmitting base material 12 to 3000 nm or more, the difference between the refractive index n _{1x in} the slow axis direction of the transparent base material 12 and the refractive index n _{1y in} the fast axis direction (hereinafter, n ") is preferably 0.05 to 0.20. If the refractive index difference? N is less than 0.05, the film thickness necessary for obtaining the aforementioned retardation value becomes thick. On the other hand, when the refractive index difference? N exceeds 0.20, tearing, crumbling, or the like is liable to occur in the light-transmitting base material 12, and practicality as an industrial material is remarkably lowered. More preferably, the lower limit of the refractive index difference DELTA n is 0.07, and the upper limit of the refractive index difference DELTA n is 0.15. When the refractive index difference? N is more than 0.15, the durability of the light-transmitting base material 12 in the heat and humidity resistance test may be poor depending on the kind of the light-transmitting base material 12. From the viewpoint of ensuring excellent durability in the heat and humidity resistance test, a more preferable upper limit of the refractive index difference DELTA n is 0.12.

Further, the refractive index n _1x in the slow axis direction dx of the light-transmitting base material 12 is preferably 1.60 to 1.80, more preferably 1.65, and still more preferably 1.75. The refractive index n _1y in the fast axis direction dy of the light-transmitting base material 12 is preferably 1.50 to 1.70, more preferably 1.55, and more preferably 1.62 (1.65). When the refractive index n _1x in the slow axis direction dx and the refractive index n _1y in the fast axis direction dy of the light-transparent base material 12 are within the above-mentioned range and the relationship of the above-described refractive index difference? N is satisfied, It is possible to obtain an effect of suppressing unevenness.

Here, the average reflectance (R) at a wavelength of 380 to 780 nm was measured using a spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation), and the following equation was used from the obtained average reflectance (R) . The average reflectance R of the functional layer 15 was determined by coating the raw material composition on PET having a thickness of 50 占 퐉 without the adhesion facilitating treatment to form a cured film having a thickness of 1 to 3 占 퐉 and applying the PET raw material composition A black vinyl tape (for example, Yamato vinyl tape NO200-38-21 38 mm wide) having a width larger than the measurement spot area is attached to the surface (back surface) of the film to prevent the reflection of the back surface, and then the average reflectance of each coating film is measured . The refractive index of the light-transmitting base material 12 can be measured after a black vinyl tape is similarly applied to the surface opposite to the measurement surface. The refractive index of the refractive index adjustment layer 13 can be measured after the surface of the laminate substrate 11 opposite to the measurement surface, that is, after attaching the black vinyl tape on the light-transmitting base material 12.

In addition, refractive index and birefringence index can be measured using Abbe's refractive index system or " Ellipsometer M150 " manufactured by Nippon Bunko Co.,

Further, as a method for measuring the refractive index n _{x in} the slow axis direction in the plane and the refractive index n _y in the fast axis direction in the plane, there is the following method. First, two polarizing plates are used to measure the alignment axis direction (the direction of the main axis, that is, the direction of the slow axis in the plane and the direction of the fast axis) of the measurement target (the light-transmitting base material 12 or the refractive index adjustment layer 13) Specify. Next, a black vinyl tape (for example, Yamato Vinyl Tape No. 200-38-21 38 mm wide) was attached to the back surface of the object to be measured, and then a spectrophotometer (V7100 type, automatic absolute reflectance measuring unit, VAR-7010 Nitobunku Co., The average of the S polarized light was measured by measuring the reflectance when the oscillation direction of the S polarized light was parallel to the direction of the slow axis of the object to be measured, Direction is parallel to the direction of the fast axis of the measurement target is measured five times to calculate an average value. It is possible to obtain the refractive index n _x in the direction of the slow axis of the measurement object as the average value of the reflectance when the oscillation direction of the S-polarized light is parallel to the direction of the slow axis of the measurement object as the reflectance R , The refractive index n _y in the fast axis direction of the object to be measured can be obtained with the average value of the reflectance in the case where the oscillation direction of the S-polarized light becomes parallel to the direction of the fast axis of the measurement object as the reflectance R (%) of the following formula.

As a method of measuring the refractive index of the functional layer 15 after the laminate 10 has been formed, a cured film of each layer is scraped off with a cutter or the like to produce a sample in a powder state, and the sample is pulverized in accordance with JIS K7142 (For the transparent material of the granular phase), a sample of the powder state is placed on a slide glass, etc., and the reagent is dropped on the sample, and the sample is immersed in the reagent. A method of observing by a microscope observation, a method of making the refractive index of the sample to be a refractive index of the sample, and a method of making the refractive index of the reagent which makes it impossible to observe the naked eye be the refractive index of the sample) can be used. Since the refractive indexes of the light-transmitting substrate 12 and the refractive index adjusting layer 13 are different depending on the direction, the average reflectance is measured by attaching the black vinyl tape to the treated surface of the laminated substrate 11 instead of the Becke method I ask.

<Light-transmitting substrate>

Next, the light-transmitting base material 12 of the laminated base material 11 will be described in detail. The light-transmitting substrate 12 is not particularly limited as long as it is a substrate having visible light transmittance with at least in-plane retardation. For example, as the light-transmitting substrate 12, a substrate made of polycarbonate, cycloolefin polymer, acrylic, polyester, or the like can be given. Among them, the polyester substrate is advantageous in terms of cost and mechanical strength. In the following description, the light-transparent base material 12 having a birefringent index in a plane is described in more detail, taking a polyester base as an example.

The material constituting the polyester base material may be a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. As specific examples of such polyesters, polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), and polyethylene-2,6-naphthalate . The polyester used for the polyester substrate may be a copolymer of the above-mentioned polyesters. The polyester may be used as a main component (for example, 80 mol% or more) and a small proportion (for example, 20 mol% ). &Lt; / RTI &gt; As the polyester, polyethylene terephthalate or polyethylene-2,6-naphthalate is particularly preferable because it has good balance of mechanical properties and optical properties. Particularly, it is preferable that it is made of polyethylene terephthalate (PET). Polyethylene terephthalate is highly versatile and easy to obtain. Further, PET is excellent in transparency, heat, or mechanical properties, and can control retardation by stretching and has a large intrinsic birefringence, so that a relatively large retardation can be obtained even if the film thickness is thin.

Examples of the method for obtaining the polyester base material include a method of melting the polyester such as PET as the material and extruding the polyester into a sheet form and stretching the unstretched polyester at a temperature of the glass transition temperature or higher by using a tenter or the like Followed by heat treatment. The transverse stretching temperature is preferably 80 to 130 占 폚, more preferably 90 to 120 占 폚. The transverse stretch ratio is preferably 2.5 to 6.0 times, more preferably 3.0 to 5.5 times. If the transverse stretching magnification exceeds 6.0 times, the transparency of the obtained polyester base tends to be lowered. If the stretching magnification is less than 2.5 times, the stretching tension is also small, and the birefringence of the obtained polyester base becomes small, The film thickness for obtaining the film becomes thick. Further, when the polyester base material is extrusion-molded into a sheet shape, stretching in the flow direction (machine direction), that is, longitudinal stretching may be performed. In this case, from the viewpoint of ensuring the value of the refractive index difference DELTA n stably within the above-mentioned preferable range, it is preferable that the longitudinal stretching is two times or less the stretching magnification. Further, instead of longitudinally stretching at the time of extrusion molding, longitudinal stretching may be performed after transverse stretching of the above-mentioned unstretched polyester under the above-described conditions. The treatment temperature at the time of the heat treatment is preferably 100 to 250 占 폚, more preferably 180 to 245 占 폚.

As a method of controlling the retardation of the polyester substrate produced by the above-described method to 3000 nm or more, a method of appropriately setting the stretching magnification, the stretching temperature, and the film thickness of the polyester substrate to be produced can be mentioned. Specifically, for example, the higher the stretching ratio, the lower the stretching temperature, and the thicker the film thickness, the easier to obtain higher retardation, the lower the stretch ratio, the higher the stretching temperature, The thinner the film, the easier it is to obtain a low retardation.

The thickness of the polyester base material is preferably in the range of 15 to 500 mu m. If it is less than 15 mu m, the retardation of the polyester base material can not be made to be not less than 3000 nm, and the anisotropy of the mechanical properties becomes remarkable, and tearing, breakage and the like are likely to occur and the practicality as an industrial material is remarkably lowered have. On the other hand, if it is more than 500 탆, the polyester base is very rigid, and the pliable property unique to the polymer film is deteriorated, and practical utility as an industrial material is lowered. A more preferable lower limit of the thickness of the polyester base material is 50 占 퐉, a more preferable upper limit is 400 占 퐉, and a more preferable upper limit is 300 占 퐉.

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

The light-transmitting substrate 12 may be subjected to a surface treatment such as a saponification treatment, a glow discharge treatment, a corona discharge treatment, an ultraviolet (UV) treatment and a flame treatment within the range not deviating from the object of the present invention.

<Refractive index adjustment layer>

Next, the refractive index adjustment layer 13 will be described in detail. The refractive index adjustment layer 13 reduces the refractive index difference of the interface between the light-transparent substrate 12 and the functional layer 15 by satisfying at least one of the conditions (a) to (i) Reflection at the interface is suppressed so that the interference fringe is not conspicuous. The refractive index adjustment layer 13 is not particularly limited as long as it has in-plane birefringence and has a visible light transmittance. The refractive index adjustment layer 13 may have a function other than the function of adjusting the refractive index between the light-transparent substrate 12 and the functional layer 15. For example, as a primer layer, more specifically, a primer layer functioning as an adhesion-facilitating layer may be provided with an in-plane refractive index difference so that the primer layer may form the refractive index-adjusting layer 13.

The refractive index adjusting layer 13 having an in-plane birefringence formed on the light-transmitting base material 12 may be formed of a molecule having refractive index anisotropy (for example, liquid crystal molecules) or a layer in which a compound is oriented. This refractive index adjustment layer 13 is obtained by applying a composition comprising anisotropic refractive index molecules or anisotropic compound of refractive index on a light-transmitting substrate 12, and curing the composition. As an example, when the light-transmitting base material 12 is made of a stretched film or the like and has a molecular orientation with regularity, the liquid crystal molecules coated on the light-transmitting base material 12, by their nature, Can be aligned with regularity corresponding to the molecular orientation of the substrate 12. The resultant refractive-index-adjusting layer 13 has in-plane birefringence corresponding to the birefringence of the light-transmitting base material 12, and the conditions (a) to (i) Can be satisfied. Further, from the standpoint of stabilizing the orientation of the refractive index anisotropic molecule and the refractive index anisotropic compound contained in the refractive index adjustment layer 13, it is not dependent only on the orientation of the light-transmitting base material 12, The refractive index anisotropic molecules contained in the adjustment layer 13 and the refractive index anisotropic compound may be positively oriented.

As another method, the refractive index adjusting layer 13 having in-plane birefringence can be obtained by stretching the resin layer. Generally, by adjusting the conditions such as temperature, and then stretching the layer made of the resin, the layer made of the resin exhibits birefringence in the plane. Thus, by forming the refractive index adjusting layer 13 on the light-transmitting base material 12 before stretching and simultaneously stretching the light-transmitting base material 12 and the refractive index adjusting layer 13, the birefringence is imparted to the light- And the birefringence corresponding to the birefringence of the light-transmitting base material 12 can also be imparted to the refractive index adjusting layer 13. [

More specifically, first, the composition for forming the refractive index adjustment layer 13 is applied on the light-transmitting base material 12 before stretching as described above, and the composition is cured on the light-transmitting base material 12, ) Is obtained. As the material for forming the refractive index adjustment layer 13, a resin material exhibiting birefringence can be widely used by stretching, and it is preferable that the affinity to the light-transmitting base material 12 is high. A thermoplastic or thermosetting polyester resin, a urethane resin, an acrylic resin, a modified material thereof and the like are exemplified as the resin material constituting the refractive index adjustment layer 13. [ Although the above-described various resin films can be used for the light-transmitting base material 12 to which the composition for forming the refractive index adjustment layer 13 is applied, it is preferable that the resin films are stretched at a low magnification in the machine direction during extrusion molding . The flatness of the light transmitting base material 12 is ensured by stretching in the machine direction (the extrusion direction in the extrusion molding of the light transmitting base material 12), so that the refractive index adjusting layer 13) can be made uniform.

Thereafter, the laminated substrate 11 including the light-transmitting base material 12 and the refractive index adjusting layer 13 formed on the light-transmitting base material 12 is heated at a temperature not lower than the glass transition point temperature, Direction. As described above, when the stretching magnification in the transverse direction is extremely large as compared with the stretching magnification in the longitudinal direction, the stretching axis of the light-transmitting base material 12 is oriented substantially in the transverse direction and, as a specific example, polyester terephthalate The slow axis of the light-transmitting base material 12 made of a film extends substantially in the transverse direction. On the other hand, the refractive index adjustment layer 13 is stretched only in the transverse direction. Therefore, even when the refractive index adjustment layer 13 is formed of a resin material that is less likely to be given birefringence than the light-transmitting base material 12, the birefringence in the anisotropy corresponding to the birefringence of the light- .

According to the above method, birefringence can be imparted not only to the light-transmitting base material 12 but also to the refractive index adjustment layer 13 by stretching processing for imparting birefringence to the light-transmitting base material 12. [ In addition, since the light transmitting base material 12 and the refractive index adjusting layer 13 are stretched in a heated state, there is an advantage that adhesion between the light transmitting substrate 12 and the refractive index adjusting layer 13 is improved .

For each refractive index of the refractive index adjusting layer (13), n _2, n _2x, n _2y, n _2a, n _2b (see Figs. 3 and 4), each of the refractive index of the substrate (12) light-transmissive n as described above _1, n _1x , n _1y and refractive indices n ₃ , n _3x , n _3y of the functional layer 15, respectively. As an 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 refractive index adjusting layer 13 can be set to 1.50 to 1.70 The refractive index n _2x of the refractive index adjusting layer 13 can be set to 1.55 to 1.75 and the refractive index n _2y of the refractive index adjusting layer 13 can be set to 1.45 to 1.65. The refractive index n _2a can be set to 1.51 to 1.69, and the refractive index n _2b of the refractive index adjusting layer 13 can be set to 1.46 to 1.64.

The refractive index adjusting layer 13 may have a thickness of 30 nm or more and 10 占 퐉 or less. When the thickness of the refractive index adjusting layer 13 is less than 30 nm, the uniformity of the refractive index adjusting layer 13 is lowered. The upper limit of the thickness of the refractive index adjusting layer 13 is not particularly set in view of the function of the refractive index adjusting layer 13, but is preferably set to 1 m or less for industrial reasons.

The thickness of the refractive index adjusting layer 13 (at the time of curing) can be measured by measuring the average value of arbitrary ten points obtained by observing the cross section of the refractive index adjusting layer 13 with an electron microscope (SEM, TEM, STEM) (Nm). In the case where the thickness of the refractive index adjustment layer 13 is very thin, measurement can be made by recording a photograph at high magnification and photographing it, and enlarging it further. In the case of enlargement, it is a thick line that the layer interface line was a very thin line so that it can be clearly recognized as a boundary line. In this case, it is sufficient to measure the center line bisecting the thick line width as a boundary line.

<Functional layer, second functional 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 intended to exhibit a certain function in the layered product 10. Specifically, for example, the functional layer 15 and the second functional layer 17 may have a hard coat property, And a layer exhibiting functions such as antistatic property or antifouling property. As described above, the number of functional layers included in the laminate 10 can be arbitrarily set to one or more according to the use of the laminate. In the laminate 10 shown in Fig. 1, the functional layer 15 is formed of a hard coat layer formed on one side of the laminated substrate 11. [ In the laminate 10 shown in Fig. 2, the functional layer 15 is formed of a hard coat layer formed on one side of the laminated substrate 11, and the second functional layer 17 is formed of a hard coat layer And a low refractive index layer formed on the surface opposite to the laminated substrate 11. Hereinafter, the hard coat layer as the functional layer 15 and the low refractive index layer as the second functional layer 17 will be described.

The hard coat layer is a layer for improving the scratch resistance of the optical film, and more specifically, a layer having a hardness of &quot; H &quot; or higher at a pencil hardness test (4.9 N load) specified by JIS K5600-5-4 . The hard coat layer is formed by applying a composition for forming a hard coat layer containing an ionizing radiation curable resin, which is a resin that is curable by ultraviolet rays or electron beams, and a photopolymerization initiator, on the laminate substrate 11, And then curing the composition for forming a hard coat layer. The hard coat layer obtained by this method is optically isotropic and has no in-plane birefringence. Therefore, the refractive indexes n ₃ , n _3x , and n _3y of the functional layer 15 made of the hard coat layer have the same value. Specifically, the refractive indexes n ₃ , n _3x and n _3y of the functional layer 15 made of the hard coat layer can be set to 1.45 to 1.65, respectively. The thickness of the hard coat layer (at the time of curing) is in the range of 0.1 to 100 탆, preferably 0.5 to 20 탆. The film thickness of the hard coat layer is a value measured by observing a cross section with an electron microscope (SEM, TEM, STEM).

Examples of the ionizing radiation curable resin of the composition for forming a hard coat layer include compounds having one or more unsaturated bonds such as compounds having an acrylate functional group. Examples of the compound having one unsaturated bond include ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. (Meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate , Polyfunctional compounds such as pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate and neopentyl glycol di (meth) Or a reaction product of the polyfunctional compound and (meth) acrylate (for example, a poly (meth) acrylate ester of polyhydric alcohol). In the present specification, "(meth) acrylate" refers to methacrylate and acrylate.

A polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroacetal resin, a polybutadiene resin, a polythiol polyene resin and the like having an unsaturated double bond, It can be used as a curable resin.

The ionizing radiation curable resin may be used in combination with a solvent-drying resin (a resin such as a thermoplastic resin or the like, which is formed into a film by simply drying a solvent added to adjust the solid content at the time of coating). By using the solvent-drying type resin in combination, it is possible to effectively prevent coating defects on the coated surface. The solvent-drying resin usable in combination with the ionizing radiation curable resin is not particularly limited and a thermoplastic resin can be generally used. The thermoplastic resin is not particularly limited, and examples thereof include a styrene resin, a (meth) acrylic resin, a vinyl acetate resin, a vinyl ether resin, a halogen-containing resin, an alicyclic olefin resin, a polycarbonate resin, A resin, a polyamide-based resin, a cellulose derivative, a silicone-based resin, and a rubber or an elastomer. The thermoplastic resin is preferably amorphous and soluble in an organic solvent (in particular, a common solvent capable of dissolving a plurality of polymers or curable compounds). Particularly, styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (such as cellulose esters) and the like are preferable from the viewpoints of film formability, transparency and weather resistance.

The composition for forming a hard coat layer may contain a thermosetting resin. The thermosetting resin is not particularly limited and examples thereof include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine- Condensation resins, silicon resins, polysiloxane resins, and the like.

The photopolymerization initiator is not particularly limited and a known photopolymerization initiator can be used. Specific examples of the photopolymerization initiator include acetophenones, benzophenones, meihylbenzoylbenzoates,? -Amyloxime esters, Acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, acid anhydrides, Further, it is preferable to mix and use a photosensitizer. Specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine and the like.

As the photopolymerization initiator, when the ionizing radiation curable resin is a resin system having a radically polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoins, benzoin methyl ethers, etc. are used alone or in combination . When the ionizing radiation curable resin is a resin system having a cationic polymerizable functional group, examples of the photopolymerization initiator include aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonic acid esters and the like. It is preferably used alone or as a mixture.

The content of the photopolymerization initiator in the composition for forming a hard coat layer is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin. If the amount is less than 1 part by mass, hardness of the hard coat layer in the layered product (10) may not be sufficient, and if it exceeds 10 parts by mass, ionization radiation does not reach the core of the film, There is a possibility that it will not be. A more preferable lower limit of the content of the photopolymerization initiator is 2 parts by mass, and a more preferable upper limit is 8 parts by mass. When the content of the photopolymerization initiator is within this range, hardness distribution does not occur in the film thickness direction, and uniform hardness tends to be obtained.

The composition for forming a hard coat layer may contain a solvent. The solvent may be selected depending on the type and solubility of the resin component to be used, and examples thereof include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol and the like), ethers Aliphatic hydrocarbons such as hexane and the like; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated aliphatic hydrocarbons such as benzene, toluene, xylene and the like; (Such as methyl acetate, ethyl acetate and butyl acetate), water, alcohols (ethanol, isopropanol, butanol, cyclohexanol and the like), cellosolve (methylcellosolve , Ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethylsulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.) May be mentioned are, or may be a mixed solvent thereof.

The content (solid content) of the raw material in the composition for forming a hard coat layer is not particularly limited, but is preferably 5 to 70 mass%, particularly preferably 25 to 60 mass%.

The composition for forming a hard coat layer may contain a conventionally known dispersant, an antioxidant, an antioxidant, an antioxidant, an antioxidant, an antioxidant, An antistatic agent, a silane coupling agent, a thickening agent, a coloring preventing agent, a colorant (pigment, a dye), a defoaming agent, a leveling agent, a flame retardant, an ultraviolet absorber, an adhesive agent, a polymerization inhibitor, an antioxidant, a surface modifier, .

The composition for forming the hard coat layer may be used by mixing a photosensitizer. Specific examples thereof include n-butylamine, triethylamine, and poly-n-butylphosphine.

The method for producing the composition for forming a hard coat layer is not particularly limited as long as the respective components can be uniformly mixed and can be carried out by using a known apparatus such as a paint shaker, a bead mill, a kneader, a mixer or the like.

The method for applying the composition for forming a hard coat layer on the laminated substrate 11 is not particularly limited and examples thereof include a spin coating method, a dipping method, a spraying method, a die coating method, a bar coating method, a roll coater method, Known methods such as a varnish coating method, a varnish coating method, a flexographic printing method, a screen printing method and a feed coater method.

The coating film formed by applying the composition for forming a hard coat layer on the laminated base material 11 is preferably heated and / or dried and cured by irradiation with active energy rays or the like, if necessary.

As the active energy ray irradiation, irradiation with ultraviolet rays or electron beams can be mentioned. Specific examples of the ultraviolet ray source include light sources such as ultrahigh pressure mercury lamp, high pressure mercury lamp, low pressure mercury lamp, carbon arc lamp, black light fluorescent lamp, metal halide lamp and the like. As the wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various types of electron beam accelerators such as a Cocross Walton type, a Bandegraft type, a resonant transformer type, an insulating core transformer type, or a linear type, a dinamic type, and a high frequency type.

The low refractive index layer is a layer which functions to lower the reflectance when light (for example, fluorescent light, natural light or the like) from the outside is reflected on the surface of the layered body 10. The low refractive index layer has a refractive index smaller than that of the hard coat layer and larger than air. Specifically, the refractive index of the low refractive index layer is preferably within a range of 1.1 to 2.0, more preferably within a range of 1.2 to 1.8, and still more preferably within a range of 1.3 to 1.6. When the refractive index of the low refractive index layer is within the above range, projection onto the laminate 10 can be effectively prevented. The refractive index of the low refractive index layer may be such that the refractive index gradually changes toward the refractive index of air from the inner side of the laminate 10 toward the surface side of the laminate 10 in the low refractive index layer do.

The material used for the low refractive index layer is not particularly limited as long as it can form the low refractive index layer having the above-mentioned refractive index, and for example, it is preferable to contain the resin material described in the above-mentioned composition for hard coat layer formation . The refractive index of the low refractive index layer can be adjusted by containing a silicon-containing copolymer, a fluorine-containing copolymer and fine particles in addition to the resin material. As the silicon-containing copolymer, for example, a silicon-containing vinylidene copolymer can be cited. Specific examples of the fluorine-containing copolymer include copolymers obtained by copolymerizing a monomer composition containing vinylidene fluoride and hexafluoropropylene, for example. Examples of the fine particles include fine particles of silica fine particles, acrylic fine particles, styrene fine particles, acryl styrene copolymer fine particles, and voids. The term &quot; fine particles having voids &quot; means a structure in which a gas is filled in the fine particles and / or a porous structure containing gas is formed, and the refractive index is lowered in inverse proportion to the occupancy rate of the gas in the fine particles Means fine particles.

In this embodiment, the functional layer 15 is formed as a hard coat layer and the second functional layer 17 is formed as a low refractive index layer. However, the present invention is not limited to these examples, Layer or the low refractive index layer, or a layer having another function such as an antistatic layer, antiglare layer, antifouling layer or the like may be included in place of at least one of the hard coat layer and the low refractive index layer.

The antistatic layer can be formed, for example, by containing an antistatic agent in the composition for forming a hard coat layer. As the antistatic agent, conventionally known antistatic agents can be used. For example, cationic antistatic agents such as quaternary ammonium salts, fine particles such as tin-doped indium oxide (ITO), and conductive polymers can be used. When the above-mentioned antistatic agent is used, its content is preferably 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 incorporating a blending agent into the composition for forming a hard coat layer. The antiglare agent is not particularly limited and various known inorganic or organic fine particles may be used. The average particle diameter of the fine particles is not particularly limited, but it is generally about 0.01 to 20 占 퐉. Further, the shape of the fine particles may be any one of a sphere shape and an ellipse shape, and preferably a sphere shape.

The above-mentioned fine particles exhibit flicker resistance, and are preferably transparent fine particles. Specific examples of such fine particles include inorganic beads, for example, silica beads, and organic beads, for example, plastic beads. Specific examples of the plastic beads include 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 and polyethylene beads .

The anti-fouling layer is a layer that plays a role of being able to easily wipe out contaminants (fingerprints, water-based or oil-based inks, pencils, etc.) on the outermost surface of the liquid crystal display device . Further, by the formation of the antifouling layer, it is possible to improve the antifouling property and scratch resistance of the liquid crystal display device. The antifouling layer may be formed of, for example, a composition comprising a antifouling agent and a resin.

The antifouling agent is mainly intended to prevent contamination of the outermost surface of the liquid crystal display device, and can impart scratch resistance to the liquid crystal display device. Examples of the antifouling agent include a fluorine-based compound, a silicon-based compound, and a mixed compound thereof. More specifically, a silane coupling agent having a fluoroalkyl group such as 2-perfluorooctylethyltriaminosilane and the like can be given, and those having an amino group can be preferably used. The resin is not particularly limited, and resin materials exemplified in the above-mentioned composition for forming a hard coat layer can be mentioned.

The antifouling layer can be formed, for example, on the hard coat layer described above. Particularly, it is preferable to form the antifouling layer so as to be the outermost surface. The antifouling layer may be replaced, for example, by imparting antifouling performance to the hard coat layer itself.

&Lt; About laminated base material and laminate >

According to the laminated base material 11 and the laminated body 10 described above as an embodiment, the functional layer 15 provided on the laminated base material 11 and the light-transparent base material 12 of the laminated base material 11 are provided with a refractive index An adjustment layer 13 is provided. The refractive index of the refractive index adjustment layer 13 has an in-plane birefringence and similarly has a refractive index along both the slow axis direction dx and the fast axis direction dy of the light-transmitting base material 12 having in-plane birefringence, And is adjusted between the light-transmitting substrate 12 and the functional layer 15. [ More specifically, there is no optical interface between the light-transmitting substrate 12 and the functional layer 15, in which the refractive index in the slow axis direction dx of the light-transmitting substrate 12 greatly changes, There is no optical interface in which the refractive index in the fast axis direction dy of the light source 12 greatly changes. In other words, there is no interface between the light-transparent substrate 12 and the functional layer 15, the reflectivity of which becomes high due to the large refractive index difference. Therefore, it is possible to effectively prevent the light incident into the laminate 10 from the functional layer 15 side from being reflected until reaching the light-transmitting base material 12 having in-plane birefringence. This makes it possible to effectively obscure the interference fringes that can be visually recognized due to the interference between the light reflected from the surface of the layered product 10 and the light reflected inside the layered product 10.

Further, by setting the retardation of the light-transmitting base material 12 to 3000 nm or more, irregularity of iridescence can be made inconspicuous. Therefore, with the laminate substrate 11 and the laminate 10 described herein, both the irregularity of the irregularity and the interference fringe can be effectively rendered invisible.

In addition, when the refractive index adjusting layer 13 is realized by the primer layer, the above-described useful working effects can be ensured without causing substantial increase in the material cost and increase in the manufacturing process. A primer layer having a thickness of less than 30 nm is formed on at least one of the space between the light-transmitting base material 12 and the refractive index adjusting layer 13 and between the refractive index adjusting layer 13 and the functional layer 15 to have a refractive index It may be provided separately from the adjustment layer 13. [ Even when a primer layer having a thickness of less than 30 nm is provided, the effect of making the interference fringe pattern of the refractive index adjusting layer 13 described above not to be conspicuous is effectively exhibited, and also, for example, Action can be expected.

&Quot; Polarizer &quot;

The laminated substrate 11 and the laminated body 10 can be used, for example, in the polarizing plate 20. Fig. 5 is a schematic configuration diagram of the laminate 10 shown in Fig. 1 and the polarizing plate 20 incorporating the laminated substrate 11. Fig. As shown in FIG. 5, the polarizing plate 20 includes a laminate 10, a polarizing element 21, and a protective film 22. The polarizing element 21 is formed on the surface of the laminated substrate 11 opposite to the surface on which the functional layer 15 is formed. The protective film 22 is provided on the surface of the polarizing element 21 opposite to the surface on which the laminated body 10 is provided. The protective film 22 may be a retardation film.

Examples of the polarizing element 21 include a stretched polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film and an ethylene-vinyl acetate copolymerization system saponified film dyed with iodine or the like.

&Quot; Liquid crystal display panel &quot;

The laminated substrate 11, the layered product 10 and the polarizing plate 20 can be incorporated in a liquid crystal display panel. 6 is a schematic configuration diagram of the laminated body 10 and the laminated substrate 11 shown in Fig. 1 and the liquid crystal display panel 30 incorporating the polarizing plate 20 shown in Fig.

6 includes a protective film 31 such as a triacetylcellulose film (TAC film), a polarizing element 32, a retardation film 33, and the like, from the light source side (backlight unit side) toward the viewer side. 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 are stacked in this order. The liquid crystal cell 35 is formed by arranging a liquid crystal layer, an orientation film, an electrode layer, a color filter, and the like between two glass substrates.

Examples of the retardation films 33 and 37 include a triacetyl cellulose film and a cycloolefin polymer film. The retardation film 37 may be the same as the protective film 22. As the adhesive constituting the adhesive layers 34 and 36, a pressure-sensitive adhesive (PSA) can be mentioned.

"Image display device"

The laminated substrate 11, the laminate 10, the polarizing plate 20, and the liquid crystal display panel 30 can be used in an image display apparatus. Examples of the image display device include a liquid crystal display (LCD), a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED) , Electronic paper, and the like. 7 is a sectional view of the laminated body 10 and the laminated substrate 11 shown in Fig. 1, the polarizing plate 20 shown in Fig. 5, and the image display device 40 ), Which is an example of a liquid crystal display.

The image display device 40 shown in Fig. 7 is a liquid crystal display. The image display device 30 is composed of a backlight unit 41 and a liquid crystal display panel 30 having a laminate 10 disposed on the observer side of the backlight unit 41. As the backlight unit 41, a known backlight unit can be used.

"Other uses"

The laminated substrate 11 and the laminated body 10 described above are used for applications other than those directly disposed on the display surface of the image display device 30 so as to be installed on the image display device 30 through the touch panel sensor You can. In this example, a touch panel device in which the laminated substrate 11 or the laminated body 10 is placed on the touch panel sensor directly or through another member is prepared in advance, and this touch panel device is provided on the image display device .

Further, the laminated base material 11 and the laminate 10 described above can be used for various purposes in which generation of interference fringe should be prevented. For example, the laminated substrate 11 and the laminated body 10 can also be used as a window of a display portion of a device such as a watch or meter.

<Examples>

In order to explain the present invention in detail, the present invention will be described with reference to the following examples, but the present invention is not limited to these examples.

A laminate according to Examples 1 and 2 and Comparative Example 1 was produced as described below. The occurrence of interference fringes and the occurrence of irregularity of iridescence were examined for each laminate manufactured.

(Example 1)

The polyethylene terephthalate material was melted at 290 占 폚, extruded into a sheet form through a film forming die, adhered on a rotating quenching drum cooled by water cooling, and cooled to prepare an unstretched film. The unstretched film was preheated at 120 DEG C for 1 minute by a biaxial stretching tester (manufactured by Toyo Seiki Co., Ltd.), stretched at a stretching magnification of 4.5 times at 120 DEG C, stretched at 90 DEG in a stretching direction at a stretching magnification of 1.5 times To obtain a light transmitting substrate having n _1x = 1.70, n _1y = 1.60, film thickness 80 μm, retardation = 8000 nm.

20% by mass of a photopolymerizable liquid crystal compound was dissolved in a mixed solvent of cyclohexanone and n-propyl alcohol (solvent ratio 9: 1) on a light-transmitting substrate to prepare a photopolymerization initiator Irg184 (Ciba Specialty Chemicals) The ink added in an amount of 5% based on the solid content was applied by a bar coater so that the film thickness after drying became 0.5 탆. Then, with heating at 70 ℃ 4 minutes to the solvent and dried removed, and the orientation of the optical polymerizable liquid crystal compound, and by irradiating ultraviolet rays to the surface coated construction, by immobilizing the photo-polymerizable liquid crystal compound, n _2x = 1.60, and n _2y = 1.55.

Subsequently, 30% by mass of optically isotropic pentaerythritol triacrylate (PETA) as a functional layer was dissolved in a MIBK solvent to prepare a photopolymerization initiator Irg184 (Ciba Specialty Chemicals Co., Ltd.) in an amount of 5% The added ink was applied by a bar coater so that the film thickness after drying was 5 占 퐉. Subsequently, heated for 2 minutes at 70 ℃ to remove the solvent, and by irradiating ultraviolet rays to the coating installation surface and fixed, by laminating a functional layer of n _3x = n _3y = 1.50, to obtain a laminated body according to the first embodiment.

(Example 2)

The polyethylene terephthalate material was melted at 290 占 폚, extruded into a sheet form through a film forming die, adhered on a rotating quenching drum cooled by water cooling, and cooled to prepare an unstretched film. This unoriented film was preheated at 120 DEG C for 1 minute by a biaxial stretching tester (manufactured by Toyo Seiki Co., Ltd.), stretched at a stretching magnification of 4.5 times at 120 DEG C, stretched at 90 DEG in the stretching direction, To obtain a light transmitting substrate having n _1x = 1.70, n _1y = 1.60, film thickness 33 μm, retardation = 3300 nm. A refractive index adjustment layer and a functional layer were formed on the obtained light-transmitting substrate in the same manner as in Example 1 to obtain a laminate according to Example 2. That is, the laminate according to the second embodiment differs from the laminate according to the first embodiment in the thickness of the light-transmitting substrate.

(Comparative Example 1)

The laminate according to Comparative Example 1 was obtained in the same manner as in the laminate according to Example 1 except that the intermediate layer made of pentaerythritol triacrylate: antimony pentoxide = 7: 3 was used in the change of the refractive index adjustment layer of Example 1, Sieve. The intermediate layer of the laminate according to Comparative Example 1 was optically isotropic, and n _2x = n _2y = 1.575.

(Reference Example 1)

The polyethylene terephthalate material was melted at 290 占 폚, extruded into a sheet form through a film forming die, adhered on a rotating quenching drum cooled by water cooling, and cooled to prepare an unstretched film. This unoriented film was preheated at 120 DEG C for 1 minute by a biaxial stretching tester (manufactured by Toyo Seiki Co., Ltd.), stretched at a stretching magnification of 4.5 times at 120 DEG C, stretched at 90 DEG in the stretching direction, To obtain a light transmitting substrate having n _1x = 1.70, n _1y = 1.60, film thickness of 28 μm, retardation = 2800 nm. On the obtained light-transmitting substrate, a refractive index adjusting layer and a functional layer were formed in the same manner as in Example 1 to obtain a laminate according to Reference Example 1. [ That is, the laminate according to the second embodiment differs from the laminate according to the first embodiment in the thickness of the light-transmitting substrate.

(Measurement of Refractive Index and Retardation of Light Transmitting Substrate)

The refractive index and retardation of the light transmitting substrate were measured as follows. First, the orientation of the orientation axis of the film is determined by using two polarizing plates after the stretching, and the refractive index (nx, ny) with respect to the wavelength 590 nm of two axes orthogonal to the orientation axis direction is calculated by the Abbe refractive index (NAR-4T manufactured by Atagosa Co., Ltd.). Here, an axis indicating a larger refractive index is defined as a slow axis. The film thickness d (nm) was measured using an electric micrometer (manufactured by Anritsu), and the unit was converted into nm. The retardation was calculated from the product of the refractive index difference (n _1x -n _1y ) and the film thickness d (nm).

(Measurement of refractive index of refractive index adjusting layer)

The refractive index of the refractive index adjusting layer was measured as follows. In the case of the photopolymerizable liquid crystal compounds used in Examples 1 and 2, polyimide as an alignment film material is applied on an optically isotropic glass substrate and subjected to rubbing treatment. On this substrate, an ink obtained by dissolving a photopolymerizable liquid crystal compound in a mixed solvent of cyclohexanone and n-propyl alcohol (solvent ratio 9: 1) in an amount of 20% by mass was applied by a spin coater so that the film thickness after drying became 1 μm Respectively. Subsequently, the substrate was heated at 70 占 폚 for 4 minutes to remove the solvent therefrom, to align the photopolymerizable liquid crystal compound, and to irradiate ultraviolet light on the coated surface to immobilize the refractive index adjusting layer Was measured for refractive index by the same method as for the light transmitting base.

(Judgment as to whether or not it has birefringence)

Whether or not birefringence has occurred was judged as follows. The in-plane retardation was measured by setting a measurement angle of 0 DEG and a measurement wavelength of 589.3 nm using a non-conjugated KOBRA-WR. The in-plane retardation of less than 20 nm was judged to have no birefringence, .

(Measurement of refractive index of isotropic material)

The refractive index of an isotropic material (intermediate layer and functional layer) was measured by an Abbe's refractometer (NAR-4T manufactured by Atago).

(Evaluation of interference stripes)

The occurrence of interference fringes in each laminate was evaluated as follows. The interference fringe pattern of the obtained anti-glare film was visually inspected using an interference fringe inspection lamp (Na lamp) manufactured by Funatech Co., and evaluated by the following criteria. The obtained antiglare film was evaluated by reflection observation, in which the opposite side of the coated surface was painted with black ink and an interference fringe inspection lamp was irradiated onto the coated surface.

○: Interference streaks are observed, but they are very thin, and there is no problem in practical use.

X: interference fringes are reliably observed.

(Rainbow Unevenness Evaluation)

The occurrence of rainbow unevenness in each sample was evaluated as follows. Each laminated substrate was placed on a polarizing element on the observer side of an LED backlit liquid crystal monitor (FLATORON IPS226V (LG Electronics Japan)) to produce a liquid crystal display device. Further, the angle formed by the slow axis of the polyester base material and the absorption axis of the polarizing element on the observer side of the liquid crystal monitor was 45 degrees. Then, the display image was observed with naked eyes and polarized sunglasses from front and oblique directions (about 50 degrees) with a cow and a spot (400 lux at the periphery of the liquid crystal monitor), and the presence or absence of irregularity of iridescence was evaluated according to the following criteria. Observations beyond polarized sunglasses are much more rigorous than the naked eye. Observation was performed by 10 people, and the maximum number of evaluations were observed.

◎: Irregular irregularities are not observed.

○: Rainbow irregularities are observed, but there is no problem in actual use.

X: Rainbow unevenness is strongly observed.

Table 1 shows the evaluation results of the interference stripes and the irregularity of iridescence.

Claims (16)

delete delete delete delete delete delete A laminated substrate,
And a functional layer formed on one side of the laminated substrate,
In the laminated substrate,
A light-transmitting substrate having in-plane birefringence,
And a refractive index adjustment layer laminated with the light-transmitting base material and having in-plane birefringence, the refractive index adjustment layer being positioned between the light-transparent base and the functional layer,
The refractive index n _1x of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light transmitting base material and the refractive index n _2x of the refractive index adjusting layer in the direction of the slow axis, The refractive index n _3x of the functional layer in a direction parallel to the slow axis direction of the light-transmitting substrate is

Lt; RTI ID = 0.0 &gt;
A refractive index n _{1y in the} direction of the fast axis perpendicular to the slow axis direction of the light-transmitting substrate, a refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light- The refractive index _n3y of the functional layer in the direction parallel to the fast axis direction of the substrate is

Lt; RTI ID = 0.0 &gt;
The refractive index n _1x of the refractive index adjusting layer in a direction parallel to the slow axis direction of the light-transmitting substrate, and the refractive index n _2x of the refractive index adjusting layer of the light- The refractive index n _3x of the functional layer in the direction parallel to the direction

Lt; RTI ID = 0.0 &gt;
The refractive index n _1y of the light-transmitting substrate in the fast axis direction, the refractive index n _2y of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light-transmitting substrate, and the refractive index n _2y of the light- The refractive index n _3y of the functional layer in a direction parallel to

Lt; / RTI &gt; 8. The method of claim 7,
Wherein the laminated substrate has retardation of 3000 nm or more. 8. The method of claim 7,
Wherein the light-transmitting substrate has retardation of 3000 nm or more. delete 8. The method of claim 7,
Wherein the functional layer is a hard coat layer. 8. The method of claim 7,
And a second functional layer provided on the side of the functional layer opposite to the side of the laminated substrate. 13. The method of claim 12,
And the second functional layer is a low refractive index layer having a refractive index lower than that of the functional layer. A polarizing element,
A polarizer comprising the laminate according to claim 7. A liquid crystal display panel comprising the polarizing plate according to claim 14. An image display apparatus comprising the polarizing plate according to claim 14.

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