JP2014119650A - Antiglare polarizing plate and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antiglare polarizing plate capable of achieving sufficient antiglare property and inhibition of glare even when the plate has a low haze.SOLUTION: The antiglare polarizing plate includes a polarizing film comprising a polyvinyl alcohol resin and an antiglare layer formed on the polarizing film, and has a total haze of 1% or less and a thickness of 100 μm or less. The antiglare layer includes a fine rugged surface having a fine rugged pattern on an opposite side to the polarizing film. In a distribution of heights of the fine rugged surface, a second derivative dlogH(f)/dfof a common logarithm of one-dimensional power spectrum H(f) of the heights with respect to a spatial frequency f is less than 0 at a spatial frequency of 0.01 μmand is larger than 0 at a spatial frequency of 0.02 μm.

Description

  The present invention relates to an antiglare polarizing plate and an image display device using the same.

  In an image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, an organic electroluminescence (EL) display, and the like, when external light is reflected on the display surface, visibility is significantly impaired. In order to prevent such reflection of external light, TVs and personal computers that emphasize image quality, video cameras and digital cameras used outdoors with strong external light, mobile phones that display using reflected light, etc. In the conventional art, an anti-glare polarizing plate has been used in order to prevent reflection of external light on the surface of the image display device.

  The anti-glare polarizing plate has anti-glare properties, expresses a good contrast when placed on the surface of the image display device, and the entire display surface becomes whitish due to scattered light when placed on the surface of the image display device. Suppressing the occurrence of so-called “whitening” in which the display becomes turbid color, and the pixel of the image display device and the surface uneven shape of the anti-glare polarizing plate when arranged on the surface of the image display device There is a demand for suppressing the occurrence of so-called “glare” that interferes and results in a luminance distribution that is difficult to see.

Patent Document 1 (Japanese Patent Laid-Open No. 2010-224427) discloses an antiglare polarizing plate in which an antiglare layer having a fine uneven surface is formed, and controls the power spectrum of the altitude of the fine uneven surface. Thus, it is disclosed that an antiglare polarizing plate excellent in antiglare performance can be obtained. Specifically, the power spectrum _H ^{1 2} at altitude spatial frequency 0.01 [mu] m ^-1 of the fine uneven surface of the antiglare polarizer, the ratio of the power spectrum _H ^{2 2} in the spatial frequency 0.04μm ^-1 _H ^{1 2} It is disclosed that an antiglare polarizing plate having excellent performance such as sufficient antiglare property and glare suppression can be obtained by setting / H ₂ ² in the range of ³ to 15.

The anti-glare polarizing plate disclosed in Patent Document 1 has a period of 50 μm or more by setting the ratio H ₁ ² / H ₂ ² of the altitude power spectrum of the fine uneven surface to a range of ³ to 15. Unevenness of the surface irregularity shape is reduced, and glare can be effectively suppressed. However, the haze, which is one of the optical characteristics of the antiglare polarizing plate, is preferably as small as possible in order to suppress the expression of good contrast and the occurrence of whitish. When the haze is lowered, the undulation of the surface uneven shape having a period of about 100 μm that contributes to the anti-glare property is reduced, and the anti-glare property may be insufficient.

  As described above, the antiglare property, the expression of good contrast, the suppression of the occurrence of whitishness, and the suppression of the generation of glare can be achieved by the method described in Patent Document 1, but further improvement in contrast is achieved. When the haze was lowered to suppress the occurrence of whitishness, the antiglare property was lowered. Further, glare may occur when the image display device is arranged on a high definition image display device.

  In order to solve this problem of insufficient antiglare property, an antireflection layer (for example, transparent support / antiglare layer / low refractive index layer or transparent support / antiglare layer / A structure of high refractive index layer / low refractive index layer, etc.) is formed, and a method of compensating for the lack of anti-glare property by reducing the reflectance is conceivable. However, when the antireflection layer is formed on the antiglare layer, it is necessary to form the antireflection layer having a uniform film thickness, which increases the cost. Further, when the film thickness of the antireflection layer is insufficient, there is a problem that quality defects such as unevenness occur.

  On the other hand, in order to solve the problem of elimination of glare, a method of imparting internal haze to the antiglare layer can be considered. However, imparting internal haze to the antiglare layer significantly reduces the contrast.

JP 2010-224427 A

  An object of this invention is to provide the anti-glare polarizing plate which can achieve sufficient anti-glare property and glare suppression even if it is a low haze.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors reduced the undulation of the period near 50 μm while the uneven surface shape of the antiglare layer had the undulation of the period near 100 μm. If it is a thing, it discovered that it became a thing which suppresses glare, expressing sufficient anti-glare property, when low haze is achieved. In addition, the distance between the pattern of the color filter or the like of the liquid crystal image display device and the fine uneven surface is reduced, that is, the thickness of the antiglare polarizing plate is reduced (specifically, the thickness of the antiglare polarizing plate is 100 μm). It has been found that glare does not occur even when arranged in a high-definition image display device. The present inventors have reached the present invention based on such findings.

That is, the present invention includes a polarizing film comprising a polyvinyl alcohol-based resin and an antiglare layer formed on the polarizing film, and has a total haze of 1% or less and a thickness of 100 μm or less. A polarizing plate,
The antiglare layer comprises a fine uneven surface having fine unevenness on the side opposite to the polarizing film,
The second derivative d ² logH ² (f) / df ² with respect to the spatial frequency f of the common logarithm of the one-dimensional power spectrum H ² (f) of the fine uneven surface is less than 0 at a spatial frequency of 0.01 μm ⁻¹ . It is an anti-glare polarizing plate characterized by being larger than 0 at a spatial frequency of 0.02 μm ⁻¹ .

  It is preferable that the proportion of the minute surfaces having an inclination angle of 5 ° or more in the fine uneven surface is less than 1%.

  The maximum cross-sectional height Rt of the fine uneven surface is preferably 0.3 μm or more and 1 μm or less.

  The present invention also relates to an image display device, wherein the antiglare polarizing plate is disposed so that the opposite side of the fine uneven surface faces a liquid crystal cell.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a low haze, the anti-glare polarizing plate which can achieve sufficient anti-glare property and glare suppression can be provided.

  Further, the glare can be further suppressed by reducing the distance between the pattern of the color filter or the like of the liquid crystal image display device and the fine uneven surface, that is, by reducing the thickness of the antiglare polarizing plate.

  Further, in the present invention, since it is not necessary to separately form an antireflection layer or the like on the antiglare layer, the cost does not increase, and unevenness that occurs when the thickness of the antireflection layer or the like is insufficient. Such as quality defects are suppressed.

It is sectional drawing which shows typically an example of the anti-glare polarizing plate of this invention. It is a perspective view which shows typically an example of the anti-glare polarizing plate of this invention. It is a schematic diagram which shows the state from which the function h (x, y) showing an altitude is obtained discretely. It is the figure which represented the altitude of the fine uneven | corrugated surface of the anti-glare polarizing plate of this invention with the two-dimensional discrete function h (x, y). Two-dimensional power spectrum _{^{H 2 (f x, f y}} ) is a schematic view for explaining a method of averaging the distance f from the origin in the frequency space. Is a diagram illustrating a common logarithm logH 2 ^(f) of the one-dimensional power spectrum obtained altitude of the fine uneven surface of the antiglare polarizer shown in FIG. 4 discrete Fourier transform. It is a schematic diagram for demonstrating the measuring method of the inclination-angle of the fine uneven | corrugated surface. It is a graph which shows an example of the histogram of inclination-angle distribution of the micro surface of the fine uneven surface of an anti-glare polarizing plate. It is a figure which shows typically a preferable example of the first half part of the manufacturing method of the metal mold | die for fine unevenness | corrugation formation. It is a figure which shows typically a preferable example of the second half part of the manufacturing method of the metal mold | die for fine unevenness | corrugation formation. It is a figure which shows the pattern used in the case of metal mold | die preparation of Examples 1, 2 and Comparative Examples 1, 2. FIG. 12 is a diagram illustrating a power spectrum G ² (f) obtained by subjecting the pattern illustrated in FIG. 11 to discrete Fourier transform. It is a diagram illustrating a common logarithm logH 2 ^(f) of the one-dimensional power spectrum calculated from the elevation of the antiglare polarizer of Examples 1 and 2. It is a diagram illustrating a common logarithm logH 2 ^(f) of the one-dimensional power spectrum calculated from the elevation of the antiglare polarizer of Comparative Example 1 and 2. It is a figure which shows the pattern used in the case of metal mold | die preparation of the comparative example 3. FIG. It is a diagram illustrating a common logarithm logH 2 ^(f) of the one-dimensional power spectrum calculated from the elevation of the antiglare polarizer of Comparative Example 3.

  The antiglare polarizing plate of the present invention includes a polarizing film made of a polyvinyl alcohol resin and an antiglare layer formed on the polarizing film, and has a total haze of 1% or less. Here, the total haze of the antiglare polarizing plate is measured as follows. After the antiglare layer is formed on the polarizing film, the antiglare polarizing plate and the glass substrate are bonded using a transparent adhesive so that the side of the polarizing film where the antiglare layer is not formed becomes the bonding surface. Then, light is incident from the glass substrate side and haze is measured in accordance with JIS K 7136. The haze thus measured corresponds to the total haze of the antiglare polarizing plate.

The antiglare layer of the present invention has a fine uneven surface having fine unevenness on the side opposite to the polarizing film, and relates to a common logarithmic spatial frequency f of an elevational one-dimensional power spectrum H ² (f) of the fine uneven surface described later. The second derivative d ² logH ² (f) / df ² is characterized by being less than 0 at a spatial frequency of 0.01 μm ⁻¹ and greater than 0 at a spatial frequency of 0.02 μm ⁻¹ . The antiglare polarizing plate of the present invention has such an antiglare layer, and thus has excellent antiglare properties and high glare suppression performance.

  Furthermore, since there is a possibility that slight glare may be confirmed when it is placed on an image display device that has recently advanced in high definition, the present inventors have conducted intensive studies. As a result, the thickness of the antiglare polarizing plate is reduced. It has been found that when the thickness is 100 μm or less, the glare is sufficiently suppressed even when it is arranged in a high-definition image display device.

  Specifically, the glare is considered to occur due to interference between the surface unevenness of the anti-glare polarizing plate and the pattern of pixels of the image display device. By setting the thickness of the antiglare polarizing plate to 100 μm or less, the distance between this pattern and the surface uneven shape is shortened. The present inventors have discovered that the shorter the distance, the more the glare is suppressed.

  Here, the anti-glare polarizing plate of the present invention has at least a polarizing film made of a polyvinyl alcohol-based resin and an anti-glare layer having a fine uneven surface having fine unevenness. In general, the polarizing plate has an adhesive layer, an optical compensation layer, an optical compensation film, a protective film, and the like for attaching to an image display device. What is the “thickness” of the antiglare polarizing plate of the present invention? The total thickness of all these layers and films.

  In the antiglare polarizing plate of the present invention, the total thickness of all layers and films is 100 μm or less. As a result of the study by the present inventors, the thinner the total thickness, the more effectively the glare is suppressed. Therefore, the total thickness of the antiglare polarizing plate is more preferably 90 μm or less, and further preferably 80 μm or less. The lower limit of the total thickness of the antiglare polarizing plate of the present invention is not particularly limited. However, since the mechanical strength as a polarizing plate tends to decrease as the total thickness decreases, it is 50 μm or more from the viewpoint of securing mechanical strength. Is preferred.

<Polarizing film>
The polarizing film used for the anti-glare polarizing plate of this invention is demonstrated. In the present invention, a polarizing film in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film is used. The polyvinyl alcohol resin constituting the polarizing film can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The degree of saponification of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually 1,000 to 10,000, preferably 1,500 to 10,000.

  The polarizing film used in the present invention includes a step of uniaxially stretching such a polyvinyl alcohol resin film, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye, and adsorbing the dichroic dye, two colors It is manufactured through a step of treating a polyvinyl alcohol-based resin film adsorbed with a functional dye with a boric acid aqueous solution and a step of washing with water after the treatment with the boric acid aqueous solution.

  Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or may be performed after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. For uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched or uniaxially stretched using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 4 to 8 times.

  In order to dye the polyvinyl alcohol resin film with the dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing the dichroic dye. Specifically, iodine or a dichroic dye is used as the dichroic dye.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight per 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 10 parts by weight per 100 parts by weight of water. It is. The temperature of this aqueous solution is usually about 20 to 40 ° C., and the immersion time in this aqueous solution is usually about 30 to 300 seconds.

  On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 0.001 to 0.01 parts by weight per 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate. The temperature of this aqueous solution is usually about 20 to 80 ° C., and the immersion time in this aqueous solution is usually about 30 to 300 seconds.

  The boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol resin film in an aqueous boric acid solution. The boric acid content in the boric acid aqueous solution is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is usually about 2 to 20 parts by weight, preferably 5 to 15 parts by weight per 100 parts by weight of water. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. After washing with water, a drying process is performed to obtain a polarizing film. The temperature of water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 2 to 120 seconds. The drying process performed thereafter is usually performed using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 ° C. The processing time in the drying process is usually about 120 to 600 seconds.

  Thus, a polarizing film made of a polyvinyl alcohol-based resin film on which iodine or a dichroic dye is adsorbed and oriented is obtained. The thickness of this polarizing film is preferably in the range of 5 μm to 30 μm. If the thickness of the polarizing film is less than 5 μm, sufficient optical properties may not be exhibited, and the mechanical strength may be insufficient. On the other hand, when the thickness of the polarizing film exceeds 30 μm, the total thickness of the antiglare polarizing plate is likely to exceed 100 μm, and as a result, glare may occur, which is not preferable.

<Anti-glare layer>
(Elevation power spectrum of fine uneven surface)
First, the power spectrum of the altitude of the fine uneven surface of the antiglare layer will be described. FIG. 1 is a cross-sectional view schematically showing the surface of the antiglare polarizing plate of the present invention. As shown in FIG. 1, the antiglare polarizing plate 1 of the present invention has a polarizing film 101 and an antiglare layer 102 formed thereon, and the antiglare layer 102 is opposite to the polarizing film 101. Are provided with a fine uneven surface having fine unevenness 2.

  Here, the “elevation of the surface of the fine unevenness” as used in the present invention means an arbitrary point P on the surface of the film 1 and a virtual plane 103 having the height at the average height of the surface of the fine unevenness (the altitude is used as a reference). 0 μm) means the linear distance in the main normal direction 5 (normal direction in the virtual plane 103) of the antiglare polarizing plate.

  Actually, the antiglare polarizing plate has an antiglare layer in which fine irregularities are formed on a two-dimensional plane, as schematically shown in FIG. Therefore, as shown in FIG. 2, the elevation of the surface of the fine unevenness is expressed by a two-dimensional function of the coordinates (x, y) when the orthogonal coordinates in the film plane are represented by (x, y). It can be expressed as h (x, y).

The elevation of the surface of the fine irregularities can be obtained from three-dimensional information of the surface shape measured by an apparatus such as a confocal microscope, an interference microscope, an atomic force microscope (AFM). The horizontal resolution required for the measuring instrument is at least 5 μm or less, preferably 2 μm or less, and the vertical resolution is at least 0.1 μm or less, preferably 0.01 μm or less. Non-contact three-dimensional surface shape / roughness measuring instruments suitable for this measurement include New View 5000 series (manufactured by Zygo Corporation, available from Zygo Corporation in Japan), three-dimensional microscope PLμ2300 (manufactured by Sensofar), etc. Can be mentioned. Since the resolution of the power spectrum of the altitude needs to be 0.005 μm ⁻¹ or less, the measurement area is preferably at least 200 μm × 200 μm, and more preferably 500 μm × 500 μm.

Next, a method for obtaining an altitude power spectrum from a two-dimensional function h (x, y) will be described. First, a two-dimensional function H (f _x , f _y ) is obtained from the two-dimensional function h (x, y) by a two-dimensional Fourier transform defined by equation (1).

Where f _x and f _y is the frequency of the x and y directions, respectively, with the dimension of reciprocal length. Further, in Expression (1), π is a pi and i is an imaginary unit. By squaring the obtained two-dimensional function H (f _x , f _y ), the two-dimensional power spectrum H ² (f _x , f _y ) can be obtained. This two-dimensional power spectrum H ² (f _x , f _y ) represents the spatial frequency distribution of the fine uneven surface of the antiglare layer.

  Hereinafter, a method for obtaining the two-dimensional power spectrum of the altitude of the fine uneven surface of the antiglare layer will be described more specifically. The three-dimensional information of the surface shape actually measured by the above confocal microscope, interference microscope, atomic force microscope or the like is generally obtained as discrete values, that is, elevations corresponding to a large number of measurement points. FIG. 3 is a schematic diagram showing a state in which the function h (x, y) representing the altitude is obtained discretely. As shown in FIG. 3, the in-plane orthogonal coordinates of the antiglare layer are displayed as (x, y), and are divided on the projection plane 3 by Δx in the x-axis direction and divided by Δy in the y-axis direction. In the actual measurement, the elevation of the surface of the fine unevenness is obtained as a discrete elevation value for each intersection of the broken lines on the projection plane 3 in actual measurement.

  The number of elevation values obtained is determined by the measurement range and Δx and Δy. As shown in FIG. 3, the measurement range in the x-axis direction is X = (M−1) Δx, and the measurement range in the y-axis direction is Y = (N -1) Assuming Δy, the number of obtained elevation values is M × N.

  As shown in FIG. 3, when the coordinates of the point of interest A on the projection plane 3 are (jΔx, kΔy) (where j is 0 or more and M−1 or less, and k is 0 or more and N−1 or less). The elevation of the point P on the film surface corresponding to the point of interest A can be expressed as h (jΔx, kΔy).

  Here, the measurement intervals Δx and Δy depend on the horizontal resolution of the measuring device, and in order to accurately evaluate the fine uneven surface, both Δx and Δy are preferably 5 μm or less, as described above, and preferably 2 μm or less. Is more preferable. Further, as described above, the measurement ranges X and Y are both preferably 200 μm or more, and more preferably 500 μm or more.

As described above, in actual measurement, the function representing the altitude of the fine uneven surface is obtained as a discrete function h (x, y) having M × N values. Obtained by measuring discrete function h (x, y) discrete by a discrete Fourier transform defined by equation (2) function _{H (f} x, _{f y)} is Motomari, discrete function _{H (f} x, _{f y)} a The discrete function H ² (f _x , f _y ) of the two-dimensional power spectrum is obtained by squaring. In the formula (2), l is an integer of −M / 2 or more and M / 2 or less, and m is an integer of −N / 2 or more and N / 2 or less. Δf _x and Δf _y are frequency intervals in the x and y directions, respectively, and are defined by equations (3) and (4).

Here, as shown in FIG. 4, since the uneven surface of the antiglare layer is randomly formed, the two-dimensional power spectrum H ² (f _x , f _y ) in the frequency space (spatial frequency region). Is symmetric about the origin (f _x = 0, f _y = 0). Therefore, the two-dimensional function H ² (f _x , f _y ) can be converted into a one-dimensional function H ² (f) having a variable f (unit: μm ⁻¹ ) from the origin in the frequency space. The anti-glare layer used in the anti-glare polarizing plate of the present invention has a one-dimensional power spectrum expressed by the one-dimensional function H ² (f).

Specifically, as shown in FIG. 5, first, in the frequency space, the distance from the origin O (f _x = 0, f _y = 0) is not less than (n−1 / 2) Δf and less than (n + 1/2) Δf. The number Nn of all the points (black dots in FIG. 5) located is calculated. In the example shown in FIG. 5, Nn = 16. Next, the total value H ² n of H ² (f _x , f _y ) of all points located at a distance of (n−1 / 2) Δf or more and less than (n + 1/2) Δf from the origin O (in FIG. 5) H ² (total value of f _x , f _y ) at the black circle points of ( ² ) is calculated, and the total value H ² n divided by the number N n of points is calculated as H ² ( It was set as the value of f).

Here, when M ≧ N, n is an integer of 0 or more and N / 2 or less, and when M <N, n is an integer of 0 or more and M / 2 or less. M and N mean the number of measurement points in the x-axis direction and the number of measurement points in the y-axis direction, respectively, as shown in FIG. Δf was set to (Δf _x + Δf _y ) / 2.

In general, the one-dimensional power spectrum obtained by the above-described method includes noise during measurement. In order to eliminate the influence of this noise when obtaining the one-dimensional power spectrum, the elevation of the surface of the fine irregularities on the antiglare layer is measured, and the one-dimensionality obtained from the elevation of each fine irregular surface. It is preferable to use the average value of the power spectrum as the one-dimensional power spectrum H ² (f). The number of locations for measuring the elevation of the fine uneven surface on the antiglare layer is preferably 3 or more, and more preferably 5 or more.

FIG. 6 shows the common logarithm logH ² (f) of the one-dimensional power spectrum of the elevation of the fine uneven surface obtained in this way. The common logarithm log H ² (f) of the one-dimensional power spectrum in FIG. 6 is an average of the one-dimensional power spectrum obtained from the elevations of the fine uneven surfaces at five different locations on the antiglare layer.

The second derivative d ² logH ² (f) / df ^{2 with} respect to the spatial frequency f of the logarithm logH ² (f) of the one-dimensional power spectrum of the elevation of the fine uneven surface is the common logarithm logH ² (f) of the one-dimensional power spectrum. It can be calculated from Specifically, the second derivative can be calculated by the difference method of Equation (6).

The second derivative d ² logH ² (f) / df ^{2 with} respect to the spatial frequency f of the common logarithm logH ² (f) of the one-dimensional power spectrum of the elevation shown in FIG. 6 is −11878 at a spatial frequency of 0.01 μm ⁻¹ . Yes, and was 8081 at a spatial frequency of 0.02 μm −1. Therefore, as is apparent from FIG. 6, the graph obtained by expressing the common logarithm logH ² (f) of the one-dimensional power spectrum at an altitude as the intensity with respect to the spatial frequency has a convex shape upward at the spatial frequency of 0.01 μm ⁻¹ . However, it has a downwardly convex shape at a spatial frequency of 0.02 μm ⁻¹ .

The antiglare layer of the antiglare polarizing plate of the present invention has a second derivative d ² logH ² (f with respect to the spatial frequency f of the common logarithm logH ² (f) of the one-dimensional power spectrum calculated from the elevation of the fine uneven surface. ) / Df ² is less than 0 at a spatial frequency of 0.01 μm ⁻¹ and greater than 0 at a spatial frequency of 0.02 μm ⁻¹ . As a result, when the common logarithm logH ² (f) of the one-dimensional power spectrum calculated from the altitude of the fine uneven surface is expressed as a function of the spatial frequency f, the graph is convex upward at the spatial frequency of 0.01 μm ⁻¹ . And having an upwardly convex shape at a spatial frequency of 0.02 μm ⁻¹ , and the surface irregularity shape of the antiglare layer is about 100 μm that contributes to the antiglare effect when the haze is reduced (0 at the spatial frequency). while having the waveform cycle equivalent) in .01Myuemu ^-1 effectively, and which effectively reduced the period of undulation in the vicinity of 50 [mu] m (corresponding to 0.02 [mu] m ^-1 at a spatial frequency).

(Inclination angle of fine uneven surface)
In addition, in the antiglare layer of the antiglare polarizing plate, the present inventors show excellent antiglare performance if each minute surface constituting the fine uneven surface exhibits a specific inclination angle distribution, It has been found that it is more effective in effectively preventing whitening. That is, it is preferable that the proportion of the minute surfaces having an inclination angle of 5 ° or more in the fine uneven surface of the antiglare layer is less than 1%. If the proportion of micro-surfaces with an inclination angle of 5 ° or more of the fine uneven surface exceeds 1%, the number of micro-surfaces with a steep inclination angle of the uneven surface increases, condensing light from the surroundings, It becomes easy to generate whitish that the display surface becomes white as a whole. In order to suppress such a condensing effect and prevent whitishness, the smaller the proportion of the micro-surfaces whose inclination angle is 5 ° or more among the fine uneven surfaces, the better, and less than 0.5% It is preferable that it is less than 0.1%.

  Here, the “inclination angle of the minute surface of the fine uneven surface” in the present invention means a point P as described later at an arbitrary point P on the surface of the antiglare layer of the antiglare polarizing plate 1 shown in FIG. It means the angle θ between the local normal 6 including the minute surface irregularities included and the main normal direction 5 of the antiglare polarizing plate. Similarly to the altitude, the inclination angle of the fine uneven surface can be obtained from three-dimensional information of the surface shape measured by an apparatus such as a confocal microscope, an interference microscope, an atomic force microscope (AFM).

  FIG. 7 is a schematic diagram for explaining a method of measuring the inclination angle of the minute surface of the minute uneven surface. A specific method for determining the tilt angle will be described. As shown in FIG. 7, a point of interest A on a virtual plane FGHI indicated by a dotted line is determined, and the point of interest on the x-axis passing there passes in the vicinity. The points B and D are approximately symmetrical with respect to the point A, and the points C and E are approximately symmetrical with respect to the point A in the vicinity of the point of interest A on the y-axis passing through the point A. , C, D, and E, the points Q, R, S, and T on the surface of the antiglare layer are determined. In FIG. 7, the in-plane orthogonal coordinates of the antiglare layer are indicated by (x, y), and the coordinates in the thickness direction of the antiglare layer are indicated by z. The plane FGHI is parallel to the x axis passing through the point C on the y axis and parallel to the x axis passing through the point E on the y axis and to the y axis passing through the point B on the x axis. It is a plane formed by the respective intersections F, G, H, and I with a straight line and a straight line passing through the point D on the x-axis and parallel to the y-axis. Further, in FIG. 7, the actual position of the surface of the antiglare layer is drawn with respect to the plane FGHI, but the actual position of the surface of the antiglare layer is naturally determined by the position taken by the point of interest A. It may come above the plane FGHI or may come below.

  And the inclination angle of the obtained surface shape data is the actual point P corresponding to the point P on the actual antiglare layer surface corresponding to the point of interest A and the four points B, C, D, E taken in the vicinity thereof. Polygon 4 plane stretched by a total of 5 points Q, R, S, and T on the surface of the antiglare layer, that is, normal vectors 6a, 6b, 6c and 6d of four triangles PQR, PRS, PST and PTQ. It can be obtained by determining the polar angle of the local normal (vector) 6 obtained on average (the angle θ formed with the main normal direction 5 in FIG. 2). After obtaining the inclination angle for each measurement point (small surface), a histogram is calculated.

  FIG. 8 is a graph showing an example of a histogram of the inclination angle distribution of the minute surface of the minute uneven surface of the antiglare layer. In the graph shown in FIG. 8, the horizontal axis is the inclination angle, and is divided in increments of 0.5 °. For example, the leftmost vertical bar shows the distribution of a set having an inclination angle in the range of 0 to 0.5 °, and the angle increases by 0.5 ° as going to the right. In the figure, the upper limit value is displayed for every two scales on the horizontal axis. For example, a portion with “1” on the horizontal axis is a set of minute surfaces whose inclination angle is in the range of 0.5 to 1 °. The distribution of. The vertical axis represents the ratio of the set to the whole, and is a value that becomes 1 when summed. In this example, the ratio of the minute surfaces whose inclination angle is 5 ° or more is substantially zero.

(Surface roughness parameter of fine uneven surface)
It is preferable that the fine surface irregularities of the antiglare layer have an arithmetic average roughness Ra in the range of 0.04 μm or more and 0.1 μm or less in accordance with JIS B 0601. Moreover, it is preferable that the maximum cross-sectional height Rt based on JIS B 0601 is 0.3 μm or more and 0.6 μm or less. Moreover, it is preferable that average length RSm based on prescription | regulation of JISB0601 is 50 micrometers or more and 130 micrometers or less.

  When the arithmetic average roughness Ra is less than 0.04 μm, the antiglare property of the antiglare layer obtained by transferring the uneven shape may be insufficient. On the other hand, when the arithmetic average roughness Ra exceeds 0.1 μm, the antiglare layer obtained by transferring the uneven shape may be whitish.

  If the maximum cross-sectional height Rt is less than 0.3 μm, the antiglare property of the antiglare layer obtained by transferring the uneven shape may be insufficient. On the other hand, when the maximum cross-sectional height Rt exceeds 0.6 μm, the antiglare layer obtained by transferring the uneven shape may be whitened, and the uniformity of the surface uneven shape is reduced. Glare may occur.

  Moreover, when average length RSm is less than 50 micrometers, the glare-proof property of the glare-proof layer obtained by transferring the uneven | corrugated shape may become inadequate. On the other hand, when average length RSm exceeds 130 micrometers, there exists a possibility that glare may generate | occur | produce in the glare-proof layer obtained by transferring the uneven | corrugated shape.

<Preparation method of glare-proof layer>
The above antiglare layer may be formed directly on the polarizing film, or an antiglare film having an antiglare layer formed on a transparent support is produced, and the antiglare film is antiglare via an adhesive layer. You may form by bonding to a polarizing film on the opposite side to a layer side.

  The antiglare layer is produced by producing a mold for forming fine irregularities by a method including a step of forming a surface shape (fine irregularities) based on a predetermined pattern on the surface of the mold base, and the irregular surface of the produced mold. After the shape is transferred to a transparent resin film or the like, the transparent resin film on which the shape of the concave and convex surface of the mold is transferred can be produced by a method including peeling from the mold.

In order to accurately form the fine uneven surface of the antiglare layer having the above-described features, a graph when the one-dimensional power spectrum of the predetermined pattern is expressed as an intensity with respect to the spatial frequency is a spatial frequency of 0.007 μm ⁻ has one maximum value in ^one or more 0.015 .mu.m ^-1 or less, and preferably has a single maximum value at a spatial frequency 0.05 .mu.m ^-1 or 0.1 [mu] m ^-1 or less. Here, the “pattern” means image data for forming the fine uneven surface of the antiglare layer, a mask having a light transmitting part and a light shielding part, and the like.

The intensity of the first local maximum spatial frequency 0.007 ^-1 or 0.015 .mu.m ^-1 following the pattern used in the manufacture of fine irregularities forming mold, the spatial frequency 0.05 .mu.m ^-1 or 0.1 [mu] m ^- It is preferably smaller than the strength at the second maximum value of ¹ or less. If the intensity of the first maximum value is greater than the second maximum value, the glare tends to increase, which is not preferable.

For example, when the pattern is image data, the two-dimensional power spectrum of the pattern is obtained by converting the image data into two-level binary image data, and then converting the gradation of the image data by a two-dimensional function g (x, y). represents, resulting two-dimensional function g (x, y) to Fourier transform two-dimensional function _{G (f} x, f _y) to calculate the resulting two-dimensional function _{G (f} x, f _y) square It is required by doing. Here, x and y represent orthogonal coordinates of the image data plane, f _x and f _y represent the frequency of the frequency and the y direction of the x-direction.

  Similarly to the case of obtaining the two-dimensional power spectrum of the altitude of the fine uneven surface of the antiglare layer, the two-dimensional function g (x, y) of the gradation is obtained as a discrete function when obtaining the two-dimensional power spectrum of the pattern. It is common to be done. In that case, the two-dimensional power spectrum may be calculated by discrete Fourier transform, similarly to the case of obtaining the two-dimensional power spectrum of the elevation of the fine uneven surface. The one-dimensional power spectrum of the pattern is obtained from the two-dimensional power spectrum of the pattern in the same manner as the one-dimensional power spectrum of the elevation of the fine uneven surface.

Anti dimensional power spectrum of the pattern for producing a glare layer has a first maximum value below the spatial frequency 0.007 ^-1 or 0.015 .mu.m ^-1, spatial frequency 0.05 .mu.m ^-1 or 0.1μm By having the second maximum value below ⁻¹ , the graph when the common logarithm of the one-dimensional power spectrum of the elevation of the fine uneven surface is expressed as the intensity with respect to the spatial frequency is convex upward at the spatial frequency of 0.01 μm ⁻¹ . Thus, an antiglare layer having a downward convex shape at a spatial frequency of 0.02 μm ⁻¹ is obtained.

A one-dimensional power spectrum of the first maximum value below the spatial frequency 0.007 ^-1 or 0.015 .mu.m ^-1, a second maximum at a spatial frequency 0.05 .mu.m ^-1 or 0.1 [mu] m ^-1 or less In order to create a pattern that has a specific spatial frequency range component from a pattern that is created by randomly arranging dots or a pattern that has a random brightness distribution that is determined by random numbers or pseudo-random numbers generated by a computer What is necessary is just to pass the band pass filter which removes.

  Here, as described above, it is preferable to appropriately form the spatial frequency distribution of the fine uneven surface of the antiglare layer. Therefore, the anti-glare layer is manufactured using a pattern having the above-described pattern, and a mold having a fine uneven surface, and the uneven surface of the manufactured mold is transferred to a photocurable resin layer or the like on a transparent support or a polarizing film. Then, an anti-glare layer is produced on the transparent support or polarizing film by peeling off the anti-glare layer and the transparent support or polarizing film onto which the uneven surface has been transferred, from the mold. Preferably, it is produced by.

  Here, examples of the embossing method include a UV embossing method using a photocurable resin and a hot embossing method using a thermoplastic resin. Among these, the UV embossing method is preferable from the viewpoint of productivity.

  In the UV embossing method, a photocurable resin layer is formed on the surface of a transparent support or a polarizing film, and the photocurable resin layer is cured by pressing the photocurable resin layer against the uneven surface of the mold. This is a method of transferring to a curable resin layer. Specifically, an ultraviolet curable resin is coated on a transparent support or a polarizing film, and the coated ultraviolet curable resin is in close contact with the uneven surface of the mold from the transparent support or the polarizing film side. The ultraviolet curable resin is cured by irradiating ultraviolet rays, and then the transparent support or polarizing film on which the cured ultraviolet curable resin layer (antiglare layer) is formed is peeled from the mold.

  Although the kind of ultraviolet curable resin in the case of using UV embossing method is not specifically limited, The commercially available appropriate thing can be used. It is also possible to use a resin that can be cured by visible light having a wavelength longer than that of ultraviolet rays by combining an ultraviolet curable resin with an appropriately selected photoinitiator. Specifically, polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate are used alone or in admixture of two or more thereof, and Irgacure 907 (manufactured by Ciba Specialty Chemicals) ), Irgacure 184 (manufactured by Ciba Specialty Chemicals), and a photopolymerization initiator such as Lucillin TPO (manufactured by BASF) can be suitably used.

  On the other hand, the hot embossing method is a method in which a transparent support formed of a thermoplastic resin is pressed against a mold in a heated state, and the surface shape of the mold is transferred to the transparent support. The transparent support used in the hot embossing method may be any material as long as it is substantially transparent. For example, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, triacetyl cellulose, norbornene compounds are used as monomers. A solvent cast film or an extruded film of a thermoplastic resin such as amorphous cyclic polyolefin can be used. These transparent resin films can also be suitably used as a transparent support for coating the ultraviolet curable resin in the UV embossing method described above.

(Anti-glare film)
The transparent support used for producing the antiglare film may be a substantially optically transparent film, such as a triacetyl cellulose film, a polyethylene terephthalate film, a polymethyl methacrylate film, a polycarbonate film, or a norbornene compound. And a resin film such as a solvent cast film of thermoplastic resin such as amorphous cyclic polyolefin and an extruded film.

  The thickness of the transparent support is preferably in the range of 10 μm to 60 μm. When the thickness of the transparent support is less than 10 μm, the mechanical strength may be insufficient. On the other hand, when the thickness of the transparent support exceeds 60 μm, the total thickness of the antiglare polarizing plate is likely to exceed 100 μm, and as a result, glare may occur, which is not preferable.

  Moreover, a conventionally well-known thing can be used as an adhesive agent used when bonding a polarizing film and a glare-proof film together. For example, water-soluble adhesives using polyvinyl alcohol resins, adhesives using cationic polymerization of epoxy resins, adhesives using radical polymerization of acrylic resins, and cationic polymerization using a mixture of epoxy resins and acrylic resins An adhesive using radical polymerization can be used. Since the thickness of the adhesive varies depending on the type of adhesive, it cannot be generally specified, but is preferably in the range of 0.1 μm to 5 μm. When the thickness of the adhesive layer is less than 0.1 μm, it is not preferable because sufficient adhesive strength may not be obtained. On the other hand, when the thickness of the adhesive layer exceeds 5 μm, the total thickness of the antiglare polarizing plate is likely to exceed 100 μm, and as a result, glare may occur, which is not preferable.

<Method for producing mold for forming fine irregularities>
Below, the method to manufacture the metal mold | die used for forming the fine unevenness | corrugation on the surface of a glare-proof layer (die for fine unevenness formation) is demonstrated. The method for producing the fine unevenness forming mold is not particularly limited as long as it is a method capable of obtaining a predetermined surface shape using the above-described pattern. However, in order to produce the fine uneven surface with high accuracy and reproducibility. [1] first plating step, [2] polishing step, [3] photosensitive resin film forming step, [4] exposure step, [5] development step, and [6] first etching step And [7] photosensitive resin film peeling step, [8] second etching step, and [9] second plating step.

  FIG. 9 is a diagram schematically illustrating a preferred example of the first half of the method for manufacturing a fine unevenness forming mold. FIG. 9 schematically shows a cross section of the mold in each step. Hereafter, each process of the manufacturing method of the metal mold | die for fine unevenness | corrugation formation of this invention is demonstrated in detail, referring FIG.

[1] First Plating Step In the method for manufacturing a mold for forming fine irregularities, first, copper plating is applied to the surface of a substrate used for the mold. Thus, by performing copper plating on the surface of the mold base, it is possible to improve the adhesion and gloss of chrome plating in the subsequent second plating step. This is because copper plating has a high covering property and a strong smoothing action, and therefore fills minute irregularities and voids of the mold base to form a flat and glossy surface. Due to the characteristics of these copper plating, even if chromium plating is performed in the second plating step described later, the roughness of the chromium plating surface that seems to be caused by minute irregularities and voids existing on the substrate is eliminated, The occurrence of fine cracks is reduced due to the high coverage of copper plating.

  The copper used in the first plating step may be a pure copper metal or may be an alloy mainly composed of copper. Therefore, “copper” in this specification means copper and a copper alloy. It means to include. Copper plating may be performed by electrolytic plating or electroless plating, but electrolytic plating is usually employed.

  When copper plating is performed, if the plating layer is too thin, the influence of the underlying surface cannot be completely eliminated, so that the thickness is preferably 50 μm or more. Although the upper limit of the plating layer thickness is not critical, generally about 500 μm is sufficient from the viewpoint of cost and the like.

  In addition, in the manufacturing method of the metal mold | die for fine unevenness | corrugation, aluminum, iron, etc. are mentioned from a viewpoint of cost as a metal material used suitably for formation of a base material. Furthermore, lightweight aluminum is more preferable from the convenience of handling. The aluminum and iron here may be pure metals, respectively, or may be an alloy mainly composed of aluminum or iron.

  The shape of the substrate is not particularly limited as long as it is an appropriate shape that has been conventionally employed in this field, and may be a flat plate shape, or a columnar or cylindrical roll. If a mold is produced using a roll-shaped substrate, there is an advantage that an antiglare polarizing plate or an antiglare film can be produced in a continuous roll shape.

[2] Polishing Step In the subsequent polishing step, the surface of the substrate that has been subjected to copper plating in the first plating step described above is polished. In the manufacturing method of the mold for forming fine irregularities, it is preferable that the base material surface is polished in a state close to a mirror surface through this process. This is because metal plates and metal rolls that serve as base materials are often subjected to machining such as cutting and grinding in order to achieve the desired accuracy, and as a result, machine marks remain on the base material surface. This is because even if the copper plating is applied, those processed eyes may remain, and the surface is not always completely smooth in the plated state. That is, even if a process described later is performed on the surface where such deep processed marks remain, unevenness such as processed marks may be deeper than the unevenness formed after each process is performed. In the case where an anti-glare polarizing plate or an anti-glare film is produced using such a mold, the optical characteristics may be unexpectedly affected. In FIG. 9 (a), a plate-shaped mold substrate 7 is subjected to copper plating on its surface in the first plating step (the copper plating layer formed in this step is not shown), and The state which was made to have the surface 8 mirror-polished by the grinding | polishing process is shown typically.

  The method for polishing the surface of the substrate on which the copper plating is applied is not particularly limited, and any of a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method can be used. Examples of the mechanical polishing method include super finishing, lapping, fluid polishing, and buff polishing. Moreover, it is good also considering the base material surface 7 for metal mold | die as a mirror surface by carrying out mirror surface cutting using a cutting tool in a grinding | polishing process. The material and shape of the cutting tool at that time are not particularly limited, and carbide tools, CBN tools, ceramic tools, diamond tools, etc. can be used, but diamond tools should be used from the viewpoint of processing accuracy. Is preferred. As for the surface roughness after polishing, the center line average roughness Ra in accordance with the provisions of JIS B 0601 is preferably 0.1 μm or less, and more preferably 0.05 μm or less. If the center line average roughness Ra after polishing is greater than 0.1 μm, the final unevenness of the mold surface may be affected by the surface roughness after polishing, which is not preferable. In addition, the lower limit of the center line average roughness Ra is not particularly limited, and there is no limit in particular because there is a natural limit from the viewpoint of processing time and processing cost.

[3] Photosensitive resin film forming step In the subsequent photosensitive resin film forming step, the photosensitive resin is applied as a solution in which the photosensitive resin is dissolved in a solvent to the surface 8 of the substrate 7 which has been mirror-polished by the above-described polishing step, and heated. -A photosensitive resin film is formed by drying. FIG. 9B schematically shows a state where the photosensitive resin film 9 is formed on the surface 8 of the base material 7.

  A conventionally known photosensitive resin can be used as the photosensitive resin. For example, a negative photosensitive resin having a property of curing the photosensitive part includes an acrylic ester monomer or prepolymer having an acrylic group or a methacrylic group in the molecule, a mixture of bisazide and diene rubber, polyvinyl thinner. Mart compounds and the like can be used. In addition, as a positive photosensitive resin having a property that a photosensitive portion is eluted by development and only an unexposed portion remains, a phenol resin type or a novolac resin type can be used. Moreover, you may mix | blend various additives, such as a sensitizer, a development accelerator, an adhesiveness modifier, and a coating property improving agent, with a photosensitive resin as needed.

  When these photosensitive resins are applied to the surface 8 of the substrate 7, in order to form a good coating film, it is preferable to dilute and apply in an appropriate solvent. Cellosolve solvents, propylene glycol solvents An ester solvent, an alcohol solvent, a ketone solvent, a highly polar solvent, or the like can be used.

  As a method for applying the photosensitive resin solution, known methods such as meniscus coating, fountain coating, dip coating, spin coating, roll coating, wire bar coating, air knife coating, blade coating, curtain coating, ring coating, etc. are used. be able to. The thickness of the coating film is preferably in the range of 1 to 10 μm after drying.

[4] In the exposure step subsequent exposure step, chromatic graph in representing the one-dimensional power spectrum above as strength against spatial frequency, one maximum in the spatial frequency 0.007 ^-1 or 0.015 .mu.m ^-1 or less In addition, a pattern having one maximum value at a spatial frequency of 0.05 μm ⁻¹ or more and 0.1 μm ⁻¹ or less is exposed on the photosensitive resin film 9 formed in the above-described photosensitive resin film forming step. The light source used in the exposure process may be appropriately selected according to the photosensitive wavelength, sensitivity, etc. of the coated photosensitive resin. For example, g line (wavelength: 436 nm) of a high pressure mercury lamp, h line (wavelength: 405 nm) of a high pressure mercury lamp. , High pressure mercury lamp i-line (wavelength: 365 nm), semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), F2 excimer laser (wavelength: 157 nm), or the like.

  In order to accurately form the surface unevenness in the method for producing a fine unevenness forming mold, it is preferable to expose the above-described pattern on the photosensitive resin film in a precisely controlled manner in the exposure step. In the manufacturing method of the fine unevenness forming mold, in order to accurately expose the above-described pattern on the photosensitive resin film, the pattern is created as image data on the computer, and the pattern based on the image data is generated by the computer. Drawing is preferably performed by laser light emitted from a controlled laser head. When performing laser drawing, a laser drawing apparatus for making a printing plate can be used. An example of such a laser drawing apparatus is Laser Stream FX (manufactured by Sink Laboratories).

  FIG. 9C schematically shows a state in which the pattern is exposed to the photosensitive resin film 9. When the photosensitive resin film is formed of a negative photosensitive resin, the exposed region 10 undergoes a crosslinking reaction of the resin by exposure, and the solubility in a developing solution described later decreases. Therefore, the unexposed area 11 in the developing process is dissolved by the developer, and only the exposed area 10 remains on the substrate surface as a mask. On the other hand, in the case where the photosensitive resin film is formed of a positive photosensitive resin, the exposed region 10 is cut by bonding of the resin by exposure, and the solubility in a developer described later increases. Therefore, the area 10 exposed in the development process is dissolved by the developer, and only the unexposed area 11 remains on the substrate surface as a mask.

[5] Development Step In the subsequent development step, when a negative photosensitive resin is used for the photosensitive resin film 9, the unexposed region 11 is dissolved by the developer, and only the exposed region 10 is gold. It remains on the mold substrate and acts as a mask in the subsequent first etching step. On the other hand, when a positive photosensitive resin is used for the photosensitive resin film 9, only the exposed region 10 is dissolved by the developer, and the unexposed region 11 remains on the mold substrate. It acts as a mask in the subsequent first etching step.

  A conventionally well-known thing can be used about the developing solution used for a image development process. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n-butylamine, etc. Secondary amines, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, secondary amines such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide Examples include alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine, and organic solvents such as xylene and toluene.

  The development method in the development step is not particularly limited, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used.

  FIG. 9D schematically shows a state where development processing is performed using a negative photosensitive resin for the photosensitive resin film 9. In FIG. 9C, the unexposed region 11 is dissolved by the developer, and only the exposed region 10 becomes the remaining mask 12 on the substrate surface. FIG. 9E schematically shows a state in which a development process is performed using a positive photosensitive resin for the photosensitive resin film 9. In FIG. 9C, the exposed area 10 is dissolved by the developer, and only the unexposed area 11 becomes the remaining mask 12 on the substrate surface.

[6] First Etching Step In the subsequent first etching step, the mold base is mainly used in a portion where there is no mask, using the photosensitive resin film remaining on the mold base surface after the development step as a mask. Etch the plated surface of the material.

  FIG. 10 is a diagram schematically showing a preferred example of the latter half of the method for producing a mold of the present invention. FIG. 10A schematically shows a state in which the mold base 7 in the region 13 without the mask is mainly etched by the first etching process. The mold base 7 below the mask 12 is not etched from the mold base surface, but the etching from the region 13 without the mask proceeds with the progress of etching. Therefore, in the vicinity of the boundary between the mask 12 and the region 13 without the mask, the mold base 7 below the mask 12 is also etched. In the vicinity of the boundary between the mask 12 and the unmasked region 13, the etching of the mold base 7 below the mask 12 is hereinafter referred to as side etching.

The etching process in the first etching step is usually performed using a ferric chloride (FeCl ₃ ) solution, a cupric chloride (CuCl ₂ ) solution, an alkaline etching solution (Cu (NH ₃ ) ₄ Cl ₂ ), etc. Although it is performed by corroding the surface, a strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that at the time of electrolytic plating can also be used. The concave shape formed on the mold base material when the etching process is performed differs depending on the type of the base metal, the type of the photosensitive resin film, the etching technique, and the like. In the following cases, the etching is performed isotropically from the metal surface in contact with the etching solution. The etching amount here is the thickness of the base material to be cut by etching.

  The etching amount in the first etching step is preferably 1 to 50 μm, more preferably 2 to 10 μm. When the etching amount is less than 1 μm, the unevenness shape is hardly formed on the metal surface, and the die is almost flat, so that the antiglare property is not exhibited. In addition, when the etching amount exceeds 50 μm, the height difference of the uneven shape formed on the metal surface becomes large, and the anti-glare layer produced using the obtained mold becomes white. It is not preferable. The etching process in the first etching step may be performed by one etching process, or the etching process may be performed twice or more. Here, when the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

[7] Photosensitive resin film peeling step In the subsequent photosensitive resin film peeling step, the remaining photosensitive resin film used as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin film peeling step, the photosensitive resin film is dissolved using a peeling solution. As the stripper, the same developer as that described above can be used. When a negative photosensitive resin film is used by changing pH, temperature, concentration, immersion time, etc., the exposed portion is exposed. When the positive photosensitive resin film is used, the photosensitive resin film in the non-exposed portion is completely dissolved and removed. The peeling method in the photosensitive resin film peeling step is not particularly limited, and methods such as immersion peeling, spray peeling, brush peeling, and ultrasonic peeling can be used.

  FIG. 10B schematically shows a state where the photosensitive resin film used as a mask in the first etching process is completely dissolved and removed by the photosensitive resin film peeling process. A first surface irregularity shape 15 is formed on the surface of the mold substrate by the mask 12 and etching using the photosensitive resin film.

[8] Second Etching Step In the second etching step, the first surface uneven shape 15 formed by the first etching step using the photosensitive resin film as a mask is blunted by an etching process. By this second etching process, there is no steep surface slope portion in the first surface irregularities 15 formed by the first etching process, and the optical characteristics of the antiglare layer produced using the obtained mold are reduced. It changes in the preferred direction. In FIG. 10C, the second etching process causes the first surface irregularity shape 15 of the mold base 7 to be blunted, a portion having a steep surface slope is blunted, and a second surface having a gentle surface slope. The state in which the surface irregularities 16 are formed is shown.

Similarly to the first etching process, the etching process of the second etching process is usually ferric chloride (FeCl ₃ ) liquid, cupric chloride (CuCl ₂ ) liquid, alkaline etching liquid (Cu (NH ₃ ) ₄ Cl ₂ ) or the like, and by corroding the surface, strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that at the time of electrolytic plating can also be used. The bluntness of the unevenness after the etching process varies depending on the type of the underlying metal, the etching technique, and the size and depth of the unevenness obtained by the first etching process. The largest factor in controlling the amount is the etching amount. The etching amount here is also the thickness of the base material to be cut by etching, as in the first etching step. If the etching amount is small, the effect of dulling the surface shape of the unevenness obtained by the first etching step is insufficient, and the optical characteristics of the antiglare layer obtained by transferring the uneven shape to a transparent film are not so good. . On the other hand, when the etching amount is too large, the uneven shape is almost lost and the die is almost flat, so that the antiglare property is not exhibited. Therefore, the etching amount is preferably in the range of 1 to 50 μm, and more preferably in the range of 4 to 20 μm. Similarly to the first etching process, the etching process in the second etching process may be performed by one etching process, or the etching process may be performed twice or more. Here, when the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

[9] Second plating step Subsequently, by performing chromium plating, the second surface irregularity shape 16 is blunted and the mold surface is protected. FIG. 10D shows a state in which the chromium plating layer 17 is formed on the second surface uneven shape 16 formed by the etching process of the second etching step as described above, and the surface 18 of the chromium plating layer is blunted. It is shown.

In the present invention, chrome plating is employed which has a glossy surface, a high hardness, a low coefficient of friction, and good release properties on the surface of a flat plate or a roll. The type of chrome plating is not particularly limited, but it is preferable to use a chrome plating that expresses a good gloss, so-called gloss chrome plating or decorative chrome plating. Chromium plating is usually performed by electrolysis, and an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used as the plating bath. By adjusting the current density and electrolysis time, the thickness of the chromium plating can be controlled.

  In the second plating step, it is not preferable to perform plating other than chromium plating. This is because plating other than chromium has low hardness and wear resistance, so that the durability as a mold is lowered, and unevenness is worn away during use or the mold is damaged. In an antiglare layer produced using such a mold, there is a high possibility that a sufficient antiglare function cannot be obtained, and there is a high possibility that defects will occur on the antiglare layer.

  Further, polishing the surface after plating is also not preferable in the present invention. By polishing, a flat part is generated on the outermost surface, which may lead to deterioration of optical characteristics, and since shape control factors increase, shape control with good reproducibility becomes difficult. Depending on the reason.

  Thus, in the present invention, it is preferable to use the chrome plated surface as the uneven surface of the mold without polishing the surface after chrome plating. This is because, by applying chromium plating to the surface on which the fine surface irregularities are formed, a mold having an irregular surface that is dulled and whose surface hardness is increased can be obtained. The bluntness of the irregularities at this time varies depending on the type of the base metal, the size and depth of the irregularities obtained from the first etching process, and the type and thickness of the plating. The greatest factor in controlling is the plating thickness. When the thickness of the chrome plating is thin, the effect of dulling the surface shape of the unevenness obtained before the chrome plating process is insufficient, and the optical characteristics of the antiglare layer obtained by transferring the uneven shape are not so good. On the other hand, when the plating thickness is too thick, productivity is deteriorated and a projection-like plating defect called a nodule is generated, which is not preferable. Therefore, the thickness of the chrome plating is preferably in the range of 1 to 10 μm, and more preferably in the range of 3 to 6 μm.

  The chromium plating layer formed in the second plating step is preferably formed to have a Vickers hardness of 800 or more, and more preferably 1000 or more. When the Vickers hardness of the chrome plating layer is less than 800, the durability when using the mold is reduced, and the decrease in hardness due to chrome plating is due to abnormalities in the plating bath composition, electrolysis conditions, etc. during the plating process. This is because the possibility of occurrence is high, and the possibility of undesirably affecting the occurrence of defects is also high.

<Protective film>
From the viewpoint of mechanical strength, the antiglare polarizing plate of the present invention may have a protective film bonded to the side opposite to the side where the antiglare layer of the polarizing film is formed. The protective film may be an optical compensation film integrated with a protective film. Specifically, the protective film used here is preferably a transparent resin film such as triacetyl cellulose, which is currently most widely used as a protective film for polarizing plates.

  Examples of protective films used in the present invention include triacetyl cellulose, amorphous polyolefin resin film, polyester resin film, acrylic resin film, polycarbonate resin film, polysulfone resin film, and alicyclic polyimide resin film. Is mentioned. Among these, a film made of triacetyl cellulose or amorphous polyolefin resin is particularly preferably used. The amorphous polyolefin-based resin usually has a cyclic olefin polymerization unit such as norbornene or a polycyclic norbornene-based monomer, and may be a copolymer of a cyclic olefin and a chain olefin. Among them, a thermoplastic saturated norbornene resin is representative. Those having a polar group introduced are also effective. As commercially available amorphous polyolefin resins, Arton (manufactured by JSR Corporation), Zeonore (manufactured by ZEON Corporation), ZEONEX (manufactured by ZEON Corporation), APO (manufactured by Mitsui Chemicals, Inc.) And Apel (Mitsui Chemicals). When using such commercially available amorphous polyolefin-based resin, the amorphous polyolefin-based resin is formed into a film, but for film formation, solvent casting method, melt extrusion method, etc. A known method is appropriately used.

  Even when the protective film is bonded to the side opposite to the side where the antiglare layer of the polarizing film is formed, it can be bonded using the above-described adhesive.

  Prior to bonding to the polarizing film, the protective film may be subjected to easy adhesion treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment on the bonding surface.

<Optical compensation film, optical compensation layer>
The antiglare polarizing plate of the present invention may have an optical compensation layer on the side opposite to the side where the antiglare layer of the polarizing film is formed. The purpose of this optical compensation layer is to compensate for retardation, birefringent films made of stretched plastic films, films in which discotic liquid crystals and nematic liquid crystals are aligned and fixed, and the liquid crystal layer described above on a film substrate. And the like formed. These optical compensation layers may be a single layer or a plurality of layers. When providing a plurality of optical compensation layers, the same type of optical compensation layer may be laminated, or different types of optical compensation layers may be laminated. For example, a birefringent film made of a stretched plastic film or the like may be laminated on the protective film-integrated optical compensation film via an adhesive, and liquid crystal is aligned on the protective film-integrated optical compensation film. It does not matter if it solidifies.

  Examples of the plastic forming the birefringent film include polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyolefin such as polypropylene, polyarylate, polyamide, amorphous polyolefin-based resin, and the like. The stretched film may be processed by an appropriate method such as uniaxial or biaxial. Moreover, the birefringent film which controlled the refractive index of the thickness direction of a film by applying shrinkage force and / or extending | stretching force under adhesion | attachment with a heat-shrinkable film may be sufficient.

  The optical compensation layer formed on the side opposite to the side on which the antiglare layer of the polarizing film is formed may be integrated using the above-mentioned adhesive, and the simplicity of the bonding work and the prevention of the occurrence of optical distortion are possible. In view of the above, a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive) described later may be used.

What is necessary is just to select an optical compensation film and an optical compensation layer suitably according to each drive mode of a liquid crystal cell. Examples of the driving mode of the liquid crystal include a vertical alignment (VA) mode, a lateral electric field (In-Plane Switching: IPS) mode, and a twisted nematic (TN) mode. In the case of a liquid crystal cell of vertical alignment mode, a film made of a transparent resin having positive refractive index anisotropy such as a cellulose resin typified by acylated cellulose such as triacetyl cellulose, a cyclic olefin resin, or polycarbonate is used. It is possible to use a film having a relationship of n _x > ny _{y nz} that is uniaxially or biaxially stretched under appropriate conditions. Here n _x plane slow axis direction of the refractive index of the film, n _y is the plane fast axis direction of the refractive index of the film, n _z represents the refractive index in the thickness direction of the film. The cyclic olefin-based resin is a resin using a cyclic olefin such as norbornene or dimethanooctahydronaphthalene as a monomer, and commercially available products include Arton (manufactured by JSR Corporation) and Zeonoa (manufactured by Nippon Zeon Corporation). ), ZEONEX (manufactured by Nippon Zeon Co., Ltd.). Among these transparent resins, triacetyl cellulose and cyclic olefin-based resins are preferably used because they have a small photoelastic coefficient and little occurrence of in-plane characteristic unevenness due to thermal strain under use conditions. Also, application of discotic liquid crystal on the substrate, application of cholesteric liquid crystal on the substrate at a short pitch, formation of an inorganic layered compound layer such as mica on the substrate, sequential or simultaneous biaxial stretching of the resin, unstretched It is also possible to use an optical compensation layer having a relationship of nx≈ny> nz, such as a solvent cast film.

  In addition, a TN mode liquid crystal cell is an organic compound, particularly a compound having a liquid crystallinity and having a discotic molecular structure, or a liquid crystal cell, but exhibiting negative refractive index anisotropy by an electric field or a magnetic field. For example, a film in which a compound to be coated is applied on a transparent resin film made of triacetylcellulose and the like so that the optical axis is inclined at 5 to 50 ° from the film normal direction is preferably used. The orientation may be not only one direction but also, for example, a so-called hybrid orientation in which the inclination gradually increases from one side of the film to the other side. Examples of organic compounds having a discotic molecular structure exhibiting liquid crystallinity include low molecular or high molecular discotic liquid crystals, such as alkyl groups, alkoxy groups, alkyls, etc., on a mother nucleus having a planar structure such as triphenylene, torquesen, and benzene. Examples include those in which linear substituents such as substituted benzoyloxy groups and alkoxy-substituted benzoyloxy groups are bonded in a radial manner. Among them, those that do not absorb in the visible light region are preferable. These organic compounds having a disk-like molecular structure are not only used alone, but may be used in combination with several kinds as necessary in order to obtain the orientation necessary for the present invention, or high It can be used by mixing with other organic compounds such as a molecular matrix. As described above, the organic compound used as a mixture is compatible with an organic compound having a discotic molecular structure, or an organic compound having a discotic molecular structure is dispersed in a particle size that does not scatter light. There is no particular limitation as long as it is possible. For example, a WV film (Fuji Photo Film Co., Ltd.) can be used as a film in which a layer made of a liquid crystal compound is provided on a transparent base film made of a cellulose resin and the optical axis is inclined with respect to the film normal. Can be suitably used. In addition, organic compounds having an elongated rod-like structure, especially those having a nematic liquid crystallinity and a molecular structure that gives positive optical anisotropy, and those that do not exhibit liquid crystallinity but have an electric or magnetic field and positive refractive index anisotropy Also preferably used is a film obtained by orienting a compound that expresses a film on a transparent substrate film made of a cellulose-based resin and the like so that the optical axis is inclined at 5 to 50 ° from the film normal direction. It is done. This orientation may be not only unidirectional but also, for example, so-called hybrid orientation in which the inclination increases sequentially from one side of the film to the other side. As a film in which a layer made of a nematic liquid crystal compound is provided on a transparent substrate film and the optical axis is inclined with respect to the film normal, for example, an NH film (manufactured by Nippon Oil Corporation) is preferably used. Can do.

<Adhesive layer>
As an adhesive for bonding the antiglare polarizing plate of the present invention to an image display device, an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether, or the like may be used as a base polymer. it can. Above all, like acrylic pressure-sensitive adhesives, it has excellent optical transparency, retains appropriate wettability and cohesion, has excellent adhesion to the base material, and has weather resistance, heat resistance, etc. It is preferable to select and use a material that does not cause peeling problems such as floating and peeling under the conditions of heating and humidification. In acrylic adhesives, alkyl esters of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as methyl, ethyl and butyl groups, and (meth) acrylic acid and hydroxyethyl (meth) acrylate An acrylic copolymer having a weight average molecular weight of 100,000 or more, in which a glass transition temperature is preferably 25 ° C. or less, more preferably 0 ° C. or less, and a functional group-containing acrylic monomer comprising Useful as a base polymer.

  The pressure-sensitive adhesive layer is formed on the polarizing plate by, for example, dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a 10 to 40% by weight solution, which is directly applied on the polarizing plate. This can be done by a method of forming a pressure-sensitive adhesive layer by coating, or a method of forming a pressure-sensitive adhesive layer by previously forming a pressure-sensitive adhesive layer on a protective film and transferring it onto a polarizing plate. Can do. Although the thickness of an adhesive layer is determined according to the adhesive force etc., the range of about 1-25 micrometers is suitable.

<Image display device>
The present invention further includes the above-described anti-glare polarizing plate of the present invention and an image display element, and the anti-glare polarizing plate is disposed on the viewing side of the image display element with the hard coat layer side facing outside. An image display apparatus is also provided.

  Here, the image display element is typically a liquid crystal panel that includes a liquid crystal cell in which liquid crystal is sealed between upper and lower substrates and displays an image by changing the alignment state of the liquid crystal by applying a voltage. In the image display device of the present invention, the antiglare polarizing plate is disposed on the viewing side with respect to the image display element. Under the present circumstances, it arrange | positions so that the uneven surface of an anti-glare layer may become an outer side (viewing side). As described above, the image display device provided with the antiglare polarizing plate of the present invention can scatter incident light due to the unevenness of the surface of the antiglare layer and blur the reflected image, giving excellent visibility. .

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

<Example 1>
(A) Production of Polarizing Film A polyvinyl alcohol film having a thickness of 75 μm, a polymerization degree of 2400, and a saponification degree of 99.9% or more is uniaxially stretched at a draw ratio of 5 times in a dry manner, and 100 parts by weight of water is kept in a tension state. The sample was immersed in an aqueous solution containing 0.05 parts by weight of iodine and 5 parts by weight of potassium iodide at a temperature of 28 ° C. for 60 seconds. Next, while maintaining the tension state, it was immersed in a boric acid aqueous solution containing 7.5 parts by weight of boric acid and 6 parts by weight of potassium iodide per 100 parts by weight of water at a temperature of 73 ° C. for 300 seconds. Then, it wash | cleaned for 10 second with 15 degreeC pure water. The film washed with water was dried at 70 ° C. for 300 seconds while keeping the tensioned state to obtain a polarizing film. The thickness of this polarizing film was 23 μm.

(B) Production of mold for forming fine unevenness A surface of an aluminum roll (A5056 according to JIS) having a diameter of 200 mm was subjected to copper ballad plating. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was set to be about 200 μm. The copper plating surface was mirror-polished, and a photosensitive resin was applied to the polished copper plating surface and dried to form a photosensitive resin film. Next, a pattern in which the pattern shown in FIG. 11 (created by passing a bandpass filter that removes a component in a specific spatial frequency range from a pattern having a random brightness distribution) is repeatedly arranged on the photosensitive resin film is laser-bonded. It was exposed to light and developed. Laser light exposure and development were performed using Laser Stream FX (manufactured by Sink Laboratory Co., Ltd.). A positive photosensitive resin was used for the photosensitive resin film.

  Then, the 1st etching process was performed with the cupric chloride liquid. The etching amount at that time was set to 4.5 μm. The photosensitive resin film was removed from the roll after the first etching treatment, and the second etching treatment was performed again with cupric chloride solution. The etching amount at that time was set to 12 μm. Then, the chromium plating process was performed and the metal mold | die A was produced. At this time, the chromium plating thickness was set to 4 μm.

  FIG. 11 is a diagram showing a part of image data which is a pattern used in this embodiment. The image data that is the pattern shown in FIG. 11 has a size of 33 mm × 33 mm and was created at 12800 dpi.

FIG. 12 is a diagram showing a power spectrum G ² (f) obtained by subjecting the pattern shown in FIG. 11 to discrete Fourier transform. Than 12, the graph in showing the one-dimensional power spectrum of the pattern used to produce the antiglare film A (Example 1) as the intensity with respect to the spatial frequency, the spatial frequency 0.007 ^-1 or 0.015 .mu.m ^-1 hereinafter has a first maximum value, it can be seen that having a second maximum value below the spatial frequency 0.05 .mu.m ^-1 or 0.1 [mu] m ^-1.

(C) Formation of an antiglare film The following components were dissolved in ethyl acetate at a solid concentration of 60% by weight, and an ultraviolet curable resin composition A having a refractive index of 1.53 after curing was obtained.

Pentaerythritol triacrylate 60 parts by weight Polyfunctional urethanized acrylate 40 parts by weight (Reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate)
Diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide 5 parts by weight.

This ultraviolet curable resin composition A was applied onto a 40 μm thick triacetylcellulose (TAC) film so that the coating thickness after drying was 7 μm, and was dried in a dryer set at 60 ° C. for 3 minutes. . The film after drying was brought into close contact with the concavo-convex surface of the mold A obtained previously with a rubber roll so that the photocurable resin composition layer was on the mold side. In this state, light from a high-pressure mercury lamp having an intensity of 20 mW / cm ² was irradiated from the TAC film side so that the amount of light in terms of h-line was 200 mJ / cm ² to cure the photocurable resin composition layer. Thereafter, the TAC film was peeled from the mold together with the cured resin, and a transparent anti-glare film A composed of a laminate of the cured resin having irregularities on the surface and the TAC film was produced.

(D) Preparation of anti-glare polarizing plate For 100 parts by weight of water, 1.8 parts by weight of carboxyl group-modified polyvinyl alcohol “Kuraray Poval KL318” (modified degree 2 mol%) sold by Kuraray Co., Ltd. Dissolve and add 1.5 parts by weight of “Smileze Resin 650” (aqueous solution with a solid content of 30% by weight) sold by Sumika Chemtex Co., Ltd., which is a water-soluble polyamide epoxy resin. A polyvinyl alcohol-based adhesive was prepared.

  After the saponification treatment is performed on the side opposite to the side on which the antiglare layer of the antiglare film A is formed, the polyvinyl alcohol-based adhesive prepared as described above is applied with a 10 μm bar coater, and is obtained on that. A polarizing film was bonded. Thereafter, it was dried at 80 ° C. for 5 minutes, and further cured at room temperature for 1 day. Thereafter, an adhesive layer is formed by transferring an acrylic adhesive layer having a thickness of 15 μm formed on the protective film to the side opposite to the side where the antiglare film is bonded to the polarizing film. The polarizing plate A was obtained. The total thickness of the antiglare polarizing plate A was 85 μm.

(E) Production of liquid crystal display device From the front surface (viewing side) of a liquid crystal cell of a commercially available notebook computer (VAIO SVS15119FJB · S, manufactured by Sony Corporation) on which an IPS mode liquid crystal display element (that is, an image display element) is mounted. The polarizing plate is peeled off, and the anti-glare polarizing plate A is bonded to the front surface of the liquid crystal cell so that the absorption axis of the polarizing plate coincides with the absorption axis direction of the polarizing plate originally attached to the liquid crystal cell. A panel was produced. Next, this liquid crystal panel was returned to the liquid crystal display element, and a liquid crystal display device A (that is, an image display device) was produced.

<Example 2>
An antiglare polarizing plate B and a liquid crystal display device B were produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was 25 μm. The total thickness of the antiglare polarizing plate B was 95 μm.

<Comparative Example 1>
An antiglare film C was produced in the same manner as in Example 1 except that a TAC film having a thickness of 60 μm was used. Further, an antiglare polarizing plate C and a liquid crystal display device C were produced in the same manner as in Example 1 except that the antiglare film C was used. The total thickness of the antiglare polarizing plate C was 105 μm.

<Comparative example 2>
The surface of a 300 mm diameter aluminum roll (JIS A5056) is mirror-polished, and the polished aluminum surface is coated with zirconia beads TZ-SX-17 (Tosoh Corp.) using a blasting device (Fuji Seisakusho). ), Average particle size: 20 μm), and blasted at a blast pressure of 0.1 MPa (gauge pressure, the same applies below) and a bead usage of 8 g / cm ² (a used amount per 1 cm ² of surface area of the roll, the same applies hereinafter). The surface was uneven. The obtained uneven aluminum roll was subjected to electroless nickel plating to produce a mold B. At this time, the electroless nickel plating thickness was set to 15 μm. An antiglare film D was produced in the same manner as in Example 1 except that the obtained mold B was used. Further, an antiglare polarizing plate D and a liquid crystal display device D were produced in the same manner as in Example 1 except that the antiglare film D was used. The total thickness of the antiglare polarizing plate D was 85 μm.

<Comparative Example 3>
A pattern in which the pattern shown in FIG. 15 (created by passing a bandpass filter that removes a component in a specific spatial frequency range from a pattern having a random brightness distribution) is repeatedly arranged on the photosensitive resin film by laser light. Except that the exposure amount was set so that the etching amount in the first etching process was 4 μm, and the etching amount in the second etching process was set to 11 μm. The anti-glare film E was produced in the same manner as in Example 1 except that the mold C was used, and the anti-glare polarizing plate E was obtained in the same manner as in Example 1 except that the anti-glare film E was used. A liquid crystal display device E was produced. The thickness of the antiglare polarizing plate E was 85 μm.

[Evaluation of anti-glare polarizing plate]
The following evaluation was performed about the anti-glare polarizing plate obtained by the said Example and the comparative example. The evaluation results are shown in Table 1. In addition, in FIG. 13, FIG. 14 and FIG. 16, the common logarithm logH ² of the one-dimensional power spectrum calculated from the altitudes of the antiglare polarizing plates A to E produced in Examples 1 and 2 and Comparative Examples 1 to 3 ( f).

[1] Measurement of surface shape of antiglare polarizing plate (Measurement of surface elevation)
The elevation of the surface of the antiglare polarizing plate was measured using a three-dimensional microscope PL μ2300 (manufactured by Sensofar). In order to prevent the sample from warping, it was subjected to measurement after being bonded to a glass substrate using an optically transparent pressure-sensitive adhesive so that the uneven surface became the surface. During the measurement, the objective lens was measured at a magnification of 10 times. The horizontal resolutions Δx and Δy were both 1.66 μm and the measurement area was 1270 μm × 950 μm.

(Power spectrum of elevation of fine surface irregularities)
512 × 512 data (measured area: 850 μm × 850 μm) are sampled from the central portion of the measurement data obtained above, and the elevation of the fine uneven surface of the anti-glare polarizing plate is expressed by a two-dimensional function h (x, y ). The two-dimensional function h (x, y) was subjected to discrete Fourier transform to obtain a two-dimensional function H (fx, fy). The two-dimensional function H (fx, fy) is squared to calculate a two-dimensional function H ² (fx, fy) of the two-dimensional power spectrum, and the one-dimensional function H of the one-dimensional power spectrum, which is a function of the distance f from the origin. ² (f) was calculated. The elevation of the surface of the five positions for each sample was measured, the one-dimensional power spectrum is calculated from these data one-dimensional function H ² dimensional function of the average value of ^(f) one-dimensional power spectrum of each sample H ² (F).

[2] Measurement of optical properties of anti-glare polarizing plate (haze)
The total haze of the anti-glare polarizing plate is obtained by bonding the anti-glare polarizing plate to a glass substrate on the surface opposite to the anti-glare layer forming surface using an optically transparent adhesive, and attaching the anti-glare polarizing plate to the glass substrate. About the combined anti-glare polarizing plate, light was incident from the glass substrate side and measured using a haze meter “HM-150” manufactured by Murakami Color Research Laboratory in accordance with JIS K 7136.

(Transparency definition)
The transmission clarity of the antiglare polarizing plate was measured using an image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. in accordance with JIS K 7105. Also in this case, in order to prevent the sample from warping, it was subjected to measurement after being bonded to a glass substrate using an optically transparent adhesive so that the fine uneven surface of the antiglare layer was the surface. . In this state, light was incident from the glass side and measurement was performed. The measured value here is a total value of values measured using four types of optical combs in which the widths of the dark part and the bright part are 0.125 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively. . In this case, the maximum value of the transmission clarity is 400%.

(Reflection sharpness)
The reflection clarity of the anti-glare polarizing plate was measured using an image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. based on JIS K 7105. Also in this case, in order to prevent the sample from warping, it is used for measurement after being bonded to a black acrylic substrate using an optically transparent adhesive so that the fine uneven surface of the antiglare layer becomes the surface. did. In this state, light was incident at 45 ° from the concavo-convex surface side, and measurement was performed. The measured value here is a total value of values measured using four types of optical combs in which the widths of the dark part and the bright part are 0.5 mm, 1.0 mm, and 2.0 mm, respectively. In this case, the maximum value of the reflection definition is 300%.

[3] Evaluation of anti-glare polarizing plate A liquid crystal display device produced by attaching an anti-glare polarizing plate to the front surface (viewing side) is set to a black display state in a bright room, and the reflection state and whiteness are visually observed. did. Next, the white display state was set in the bright room, and the glare was also visually observed. The evaluation criteria for reflection, whiteness, and glare are as follows.

(Reflection)
1: Reflection is not observed.
2: Reflection is slightly observed.
3: Reflection is clearly observed.

(White)
1: No whitishness is observed.
2: A little whitish is observed.
3: The whitish is clearly observed.

(Glitter)
1: No glare is observed.
2: Very slight glare is observed.
3: Severe glare is observed.

As shown in Table 1, for antiglare polarizing plates A to C (Examples 1 and 2, Comparative Example 1), the second derivative d ² logH ² (f ) / Df ² was less than 0 at a spatial frequency of 0.01 μm ⁻¹ and greater than 0 at a spatial frequency of 0.02 μm ⁻¹ . Accordingly, as shown in FIGS. 13 and 14, the graph showing the common logarithm of the power spectrum of the altitude of the antiglare polarizing plates A to C as the intensity with respect to the spatial frequency is shown above at the spatial frequency of 0.01 μm ⁻¹ . It had a convex shape and had a downward convex shape at a spatial frequency of 0.02 μm ⁻¹ .

On the other hand, for the antiglare polarizing plate D (Comparative Example 2), the second derivative d ² logH ² (f) / df ² related to the spatial frequency of the common logarithm of the power spectrum of the altitude is 0 at the spatial frequency of 0.01 μm ⁻¹ . It was larger and less than 0 at a spatial frequency of 0.02 μm ⁻¹ . As a result, as shown in FIG. 14, the graph representing the common logarithm of the power spectrum of the antiglare polarizing plate D as the intensity with respect to the spatial frequency has a downward convex shape at the spatial frequency of 0.01 μm ⁻¹ , It had an upwardly convex shape at a frequency of 0.02 μm ⁻¹ .

For anti-glare polarizing plate E (Comparative Example 3), the second derivative d ² logH ² (f) / df ² related to the common logarithmic spatial frequency of the power spectrum at altitude is 0 at a spatial frequency of 0.01 μm ⁻¹ . It was larger than 0 even at a spatial frequency of 0.02 μm ⁻¹ . As a result, as shown in FIG. 16, the graph representing the common logarithm of the power spectrum of the antiglare polarizing plate E as the intensity with respect to the spatial frequency has a downward convex shape at the spatial frequency of 0.01 μm ⁻¹ , Even at a frequency of 0.02 μm ⁻¹ , it had a downwardly convex shape.

Anti-glare polarizing plates A and B (Examples 1 and 2) satisfying the requirements of the present invention exhibited necessary and sufficient anti-glare properties and excellent glare-suppressing effects despite low haze. On the other hand, the anti-glare polarizing plate C (Comparative Example 1) showing the same spatial frequency characteristics as the anti-glare polarizing plates A and B also showed the necessary and sufficient anti-glare property, but the thickness of the polarizing plate is 105 μm. In addition, glare was observed. Moreover, the anti-glare polarizing plate D (Comparative Example 2) in which the graph representing the common logarithm of the power spectrum of the altitude as the intensity with respect to the spatial frequency had a convex shape at the spatial frequency of 0.02 μm ⁻¹ was obtained. A strong glare was observed. In addition, the antiglare polarizing plate E (Comparative Example 3) in which the graph representing the common logarithm of the power spectrum of the altitude as the intensity with respect to the spatial frequency had a downwardly convex shape at the spatial frequency of 0.01 μm ⁻¹ was obtained. Reflection occurred and the antiglare property was insufficient.

  DESCRIPTION OF SYMBOLS 1 Anti-glare polarizing plate, 101 Polarizing film, 102 Anti-glare layer, 103 Virtual plane, 2 Fine unevenness, 3 Projection surface, 5 Main normal direction, 6 Local normal, 6a-6d Polygon surface Normal vector, 7 Mold substrate, 8 Surface of substrate polished by polishing process, 9 Photosensitive resin film, 10 Exposed area, 11 Unexposed area, 12 Mask, 13 Unmasked area , 15 1st surface uneven shape (uneven shape on the surface of the mold base after the first etching step), 16 16 Second surface uneven shape (uneven shape on the surface of the mold base after the second etching step) , 17 Chrome plating layer, 18 Surface of the chromium plating layer.

Claims (4)

An antiglare polarizing plate comprising a polarizing film made of a polyvinyl alcohol resin and an antiglare layer formed on the polarizing film, having a total haze of 1% or less and a thickness of 100 μm or less. ,
The antiglare layer comprises a fine uneven surface having fine unevenness on the side opposite to the polarizing film,
The second derivative d ² logH ² (f) / df ² with respect to the spatial frequency f of the common logarithm of the one-dimensional power spectrum H ² (f) of the fine uneven surface is less than 0 at a spatial frequency of 0.01 μm ⁻¹ . An anti-glare polarizing plate characterized by being greater than 0 at a spatial frequency of 0.02 μm ⁻¹ .   The anti-glare polarizing plate according to claim 1, wherein a ratio of minute surfaces having an inclination angle of 5 ° or more in the fine uneven surface is less than 1%.   The anti-glare polarizing plate according to claim 1 or 2, wherein a maximum cross-sectional height Rt of the fine uneven surface is 0.3 µm or more and 1 µm or less.   An image display device, wherein the antiglare polarizing plate according to any one of claims 1 to 3 is disposed so that a side opposite to the surface of the fine unevenness faces a liquid crystal cell.