WO2020067135A1

WO2020067135A1 - Transparent article

Info

Publication number: WO2020067135A1
Application number: PCT/JP2019/037540
Authority: WO
Inventors: 隆義齊藤
Original assignee: 日本電気硝子株式会社
Priority date: 2018-09-25
Filing date: 2019-09-25
Publication date: 2020-04-02
Also published as: JPWO2020067135A1

Abstract

In order to improve the photopic contrast of a transparent article having an anti-glare surface with a recess and protrusion structure, the transparent article has an anti-glare surface 12a having a recess and protrusion structure. In the recess and protrusion structure of the anti-glare surface 12a, gradient angles of 5º or greater constitute no more than 45% of the gradient angles in a distribution of gradient angles formed by a normal line n0 of the anti-glare surface 12a and normal lines n1 of differential planes dS of the anti-glare surface 12a.

Description

Transparent goods

The present invention relates to a transparent article having an anti-glare surface having a concavo-convex structure.

(4) From the viewpoint of improving the visibility of the display device, it has been proposed that the surface of the transparent article disposed on the display surface of the display device be provided with an anti-glare effect as an anti-glare surface. The anti-glare effect by the anti-glare surface is exhibited based on the uneven structure of the anti-glare surface. Therefore, the function of the anti-glare surface can be controlled by adjusting the uneven structure of the anti-glare surface. For example, in Patent Document 1, sparkle (glare due to the sparkle phenomenon) is suppressed by setting the surface roughness Sq (RMS surface roughness) of the antiglare surface provided on the surface of the transparent glass plate to a specific range. Is disclosed.

Japanese Patent No. 6013378

Incidentally, one of the characteristics required for the display device is that the contrast (bright place contrast) under a bright place such as an environment where sunlight enters is high.
An object of the present invention is to provide a transparent article having excellent light place contrast.

The transparent article for solving the above-mentioned problem is a transparent article having an anti-glare surface having an uneven structure, wherein the uneven structure of the anti-glare surface has a gradient formed by a normal line of the anti-glare surface and a normal line of a minute plane in the anti-glare surface. The ratio of a gradient angle of 5 ° or more in the angular distribution is 45% or less.

において In the transparent article, it is preferable that the transparent article includes a transparent substrate made of glass and an anti-glare layer provided on the transparent substrate.

According to the present invention, the bright place contrast of a transparent article can be improved.

Explanatory drawing of a transparent article. FIG. 9 shows the gradient angle distribution of the anti-glare surface in Test Example 3 and Test Example 10. 9 shows the integrated distribution of the inclination angles of the antiglare surfaces in Test Example 3 and Test Example 10. 18 is a graph of the autocorrelation function of the anti-glare surface of Test Example 10. FIG. 4 is an explanatory diagram of a method for measuring a sparkle value.

Hereinafter, an embodiment of the present invention will be described.
The transparent article of the present embodiment is used by being arranged on a display surface of a display device. The transparent article may be a member attached on the display surface of the display device. That is, the transparent article may be a member that is later attached to the display device. The pixel density of the display device to which the transparent article is applied is preferably, for example, 160 to 700 ppi (pixels per inch), and more preferably 420 to 700 ppi.

As shown in FIG. 1, the transparent article 10 includes a plate-shaped translucent transparent substrate 11. The thickness of the transparent substrate 11 is, for example, 0.1 to 5 mm. Examples of the material of the transparent substrate 11 include glass and resin. The material of the transparent substrate 11 is preferably glass. As the glass, for example, known glass such as non-alkali glass, aluminosilicate glass, and soda lime glass can be used. Further, tempered glass such as chemically strengthened glass or crystallized glass such as LAS-based crystallized glass can be used. Among these, use of aluminosilicate glass, in particular, by mass%, SiO ₂ : 50 to 80%, Al ₂ O ₃ : 5 to 25%, B ₂ O ₃ : 0 to 15%, Na ₂ O: It is preferable to use chemically strengthened glass containing 1 to 20% and K ₂ O: 0 to 10%. In addition, examples of the resin include polymethyl methacrylate, polycarbonate, and epoxy resin.

アンチ An anti-glare layer 12 constituting an anti-glare surface 12a having a concavo-convex structure for scattering light is provided on one main surface of the transparent substrate 11. The surface roughness Ra of the anti-glare surface 12a is, for example, 30 to 200 nm.

The anti-glare layer 12 etches, for example, a transparent substrate made of glass, or forms a matrix made of an inorganic oxide such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , or TiO ₂ on the transparent substrate 11. It is constituted by. In the case of the etching method, an antiglare surface 12a of the present invention (an antiglare surface 12a having a concavo-convex structure described later) can be obtained by adjusting an etchant and etching conditions. The uneven structure serving as the anti-glare surface 12a includes, for example, an island-shaped uneven structure having a flat portion between a plurality of island-shaped convex portions. It is preferable that the anti-glare layer 12 is composed of only an inorganic oxide or contains no organic compound.

The anti-glare layer 12 can be formed, for example, by applying a coating agent containing a matrix precursor and a liquid medium that dissolves the matrix precursor to the surface of the transparent substrate 11 and heating (anti-glare surface forming step). The matrix precursor contained in the coating agent includes, for example, inorganic precursors such as a silica precursor, an alumina precursor, a zirconia precursor, and a titania precursor. A silica precursor is preferred because the refractive index of the antiglare layer 12 is lowered and the reactivity is easily controlled.

Examples of the silica precursor include a silane compound having a hydrocarbon group and a hydrolyzable group bonded to a silicon atom, a hydrolyzed condensate of the silane compound, and a silazane compound. It is preferable to include at least one or both of a silane compound and a hydrolysis-condensation product thereof, since cracks in the anti-glare layer 12 can be sufficiently suppressed even when the anti-glare layer 12 is formed thick.

The silane compound has a hydrocarbon group bonded to a silicon atom and a hydrolyzable group. The hydrocarbon group is one or two selected from —O—, —S—, —CO—, and —NR′— (R ′ is a hydrogen atom or a monovalent hydrocarbon group) between carbon atoms. You may have the group which combined two or more.

は The hydrocarbon group may be a monovalent hydrocarbon group bonded to one silicon atom, or may be a divalent hydrocarbon group bonded to two silicon atoms. Examples of the monovalent hydrocarbon group include an alkyl group, an alkenyl group, and an aryl group. Examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group, and an arylene group.

Examples of the hydrolyzable group include an alkoxy group, an acyloxy group, a ketoxime group, an alkenyloxy group, an amino group, an aminoxy group, an amide group, an isocyanate group, and a halogen atom. From the viewpoint of balance with the above, an alkoxy group, an isocyanate group, and a halogen atom (particularly a chlorine atom) are preferred. As the alkoxy group, an alkoxy group having 1 to 3 carbon atoms is preferable, and a methoxy group or an ethoxy group is more preferable.

Examples of the silane compound include alkoxysilane (tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, etc.), alkoxysilane having an alkyl group (methyltrimethoxysilane, ethyltriethoxysilane, etc.), alkoxysilane having a vinyl group (vinyl Trimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilane having an epoxy group (2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyl Examples thereof include diethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like, and alkoxysilanes having an acryloyloxy group (such as 3-acryloyloxypropyltrimethoxysilane). Among these silane compounds, it is preferable to use one or both of an alkoxysilane and a hydrolysis-condensation product of an alkoxysilane, and it is more preferable to use a hydrolysis-condensation product of an alkoxysilane.

Silazane compounds are compounds having a bond of silicon and nitrogen (—SiN—) in the structure. The silazane compound may be a low molecular compound or a high molecular compound (a polymer having a predetermined repeating unit). Examples of low molecular silazane compounds include hexamethyldisilazane, hexaphenyldisilazane, dimethylaminotrimethylsilane, trisilazane, cyclotrisilazane, 1,1,3,3,5,5-hexamethylcyclotrisilazane and the like. Can be

Examples of the alumina precursor include aluminum alkoxide, a hydrolyzed condensate of aluminum alkoxide, a water-soluble aluminum salt, and an aluminum chelate. Examples of the zirconia precursor include zirconium alkoxide, a hydrolyzed condensate of zirconium alkoxide, and the like. Examples of the titania precursor include titanium alkoxides, hydrolysis condensates of titanium alkoxides, and the like.

The liquid medium contained in the coating agent is a solvent for dissolving the matrix precursor, and is appropriately selected according to the type of the matrix precursor. Examples of the liquid medium include water, alcohols, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds, and sulfur-containing compounds.

Examples of the alcohols include methanol, ethanol, isopropanol, butanol, diacetone alcohol and the like. Examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of the ethers include tetrahydrofuran, 1,4-dioxane, and the like. Examples of cellosolves include methyl cellosolve, ethyl cellosolve and the like. Esters include methyl acetate, ethyl acetate and the like. Examples of glycol ethers include ethylene glycol monoalkyl ether. Examples of the nitrogen-containing compound include N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone and the like. Examples of the sulfur-containing compound include dimethyl sulfoxide. As the liquid medium, one type may be used alone, or two or more types may be used in combination.

The liquid medium is preferably a liquid medium containing water, that is, water, or a mixed liquid of water and another liquid medium. As the other liquid medium, alcohols are preferable, and methanol, ethanol, isopropyl alcohol, and butanol are particularly preferable.

The coating agent may include an acid catalyst that promotes hydrolysis and condensation of the matrix precursor. The acid catalyst is a component that promotes hydrolysis and condensation of the matrix precursor and forms the antiglare layer 12 in a short time. The acid catalyst may be added for the hydrolysis and condensation of the raw material (alkoxysilane, etc.) during the preparation of the solution of the matrix precursor prior to the preparation of the coating agent. It may be further added after preparation. Examples of the acid catalyst include inorganic acids (such as nitric acid, sulfuric acid, and hydrochloric acid) and organic acids (such as formic acid, oxalic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid).

Examples of the coating method of the coating agent include known wet coating methods (spray coating method, spin coating method, dip coating method, die coating method, curtain coating method, screen coating method, inkjet method, flow coating method, gravure coating method, bar coating method). Method, flexo coating method, slit coating method, roll coating method, etc.). As a coating method, a spray coating method is preferable because irregularities are easily formed. The anti-glare surface 12a of the present invention (the anti-glare surface 12a having a concavo-convex structure to be described later) has a nozzle diameter, an atomizing air pressure for spraying a coating agent, an application amount per unit area of the coating agent, and a transparent substrate for application. It can be obtained by appropriately adjusting the surface temperature of the material 11.

ノズル Examples of the nozzle used for the spray coating method include a two-fluid nozzle and a one-fluid nozzle. The particle size of the droplet of the coating agent discharged from the nozzle is usually 0.1 to 100 μm, preferably 1 to 50 μm. When the particle diameter of the droplet is 0.1 μm or more, it is possible to form irregularities in which the anti-glare effect is sufficiently exhibited in a short time. When the particle diameter of the droplet is 100 μm or less, it is easy to form appropriate unevenness for sufficiently exhibiting the antiglare effect. The particle size of the droplets of the coating agent can be appropriately adjusted depending on the type of nozzle, the atomizing air pressure, the liquid amount, and the like. For example, in a two-fluid nozzle, the droplet becomes smaller as the atomizing air pressure becomes higher, and the droplet becomes larger as the amount of liquid increases. The particle size of the droplet is a Sauter average particle size measured by a laser measuring device.

(4) The surface temperature of the application target (eg, the transparent substrate 11) when applying the coating agent is, for example, 20 to 75 ° C., preferably 30 ° C. or higher, and more preferably 60 ° C. or higher. As a method for heating the application target, for example, it is preferable to use a heating device of a hot water circulation type. The humidity at the time of applying the coating agent is, for example, 20 to 80%, and preferably 50% or more.

As shown in FIG. 2, the uneven structure of the anti-glare surface 12 a of the transparent article 10 of the present embodiment has a gradient angle γ formed by a normal n ₀ of the anti-glare surface 12 a and a normal n ₁ of the minute plane dS on the anti-glare surface 12 a. Is an uneven structure in which the ratio of the region where is not less than 5 ° (hereinafter referred to as the ratio of the gradient angle of not less than 5 °) is small. Specifically, the ratio of the gradient angle 5 ° or more in the gradient angle distribution of the gradient angle γ is 45% or less, and preferably 41% or less. The uneven structure of the antiglare surface 12a is preferably an uneven structure having a peak in a range of 0.1 ° or more and 5 ° or less in a gradient angle distribution of the gradient angle γ.

The gradient angle distribution of the gradient angle γ can be obtained from the three-dimensional shape z (x, y) measured using a known laser microscope. As a laser microscope, it is preferable to use a laser microscope capable of measuring with an XY resolution of 0.3 μm or less and a height resolution of 0.5 nm or less, since measurement with high resolution can be performed. The measurement conditions are not particularly limited, but it is preferable to set the measurement range to 200 μm or more × 200 μm or more, and the measurement point density to 12 Point / μm ² or more. The minute plane dS is a surface including three points that are near or adjacent to each other, and the interval between these two points is preferably 0.2 μm to 0.3 μm in the x-axis or y-axis direction. In the gradient angle distribution of the gradient angle γ, it is preferable to obtain the frequency of the gradient angle in the range of 0 ° to 90 ° at intervals of 0.2 °.

3 and 4 show examples of the gradient angle distribution of the gradient angle γ on the anti-glare surface 12a and an example of the integrated distribution thereof. When the ratio of the gradient angle of 5 ° or more in the gradient angle distribution of the gradient angle γ is 45% or less, the bright place contrast when the transparent article 10 is applied to the display surface of the display device (for example, in an environment where sunlight is incident). Contrast in a bright place) can be increased. Therefore, when used in a light place, it becomes difficult to feel white blur or the like.

Further, the uneven structure of the antiglare surface 12a of the transparent article 10 can be defined based on, for example, a period length d obtained from an autocorrelation function G _x (τ) represented by the following equation (1). It is preferable that the period length d of the uneven structure is short.

The autocorrelation function G _x (τ) expressed by the equation (1) is represented by orthogonal coordinates (x, y) in a direction parallel to the antiglare surface 12a and z in a direction perpendicular to the antiglare surface 12a. Of the three-dimensional shape z (x, y) of the anti-glare surface 12a. “X” in Expression (1) is the length (measured length) of the target range in the x direction on the antiglare surface 12a.

The three-dimensional shape z (x, y) can be measured using a known laser microscope. As a laser microscope, it is preferable to use a laser microscope capable of measuring with an XY resolution of 0.3 μm or less and a height resolution of 0.5 nm or less, since measurement with high resolution can be performed. The measurement conditions are not particularly limited, but it is preferable to set the measurement range to 200 μm or more × 200 μm or more, and the measurement point density to 12 Point / μm ² or more. In a practical measurement of the uneven structure of the antiglare surface 12a using an optical device such as a laser microscope, the three-dimensional shape z (x, y) of the uneven structure of the antiglare surface 12a can be obtained by a matrix of discrete height information. . This anti-glare surface 12a based on a matrix of discrete height information autocorrelation function G _{x (m)} will be described. The size of the matrix of discrete height information is represented as N × M, where N corresponds to the y-axis coordinate and M corresponds to the x-axis coordinate. When the shift amount of the height profile in the x-axis direction is τ (μm) and the data interval in the x-axis direction is Δx (μm), m = τ / Δx. A first-order autocorrelation function G _x (m) obtained by averaging the autocorrelation function of the height profile in the x-axis direction in the y-axis direction is represented by Expression (2). In the equation (2), k represents a column number (1 to M) corresponding to the x coordinate, and 1 represents a row number (1 to N) corresponding to the y coordinate.

FIG. 5 shows an example of a graph of the autocorrelation function G _x (τ) of the anti-glare surface 12a. As shown in the graph of FIG. 5, the autocorrelation function G _x (τ) largely decreases as the value of τ increases from “0”, then increases, and repeats a decrease and an increase at a constant cycle.

The cycle length d is the length of the cycle in which the decrease and the increase in the autocorrelation function G _x (τ) are repeated. When the inflection point where the autocorrelation function G _x (τ) changes from a decreasing trend to an increasing trend is defined as a first inflection point, and the inflection point where the increasing trend changes to a decreasing trend is defined as a second inflection point, the period length d Is obtained as the minimum value of the τ value at the second inflection point. Note that when calculating the cycle length d, small changes due to noise or the like are ignored.

(4) The uneven length structure of the antiglare surface 12a preferably has a period length d of 20 μm or less, preferably 17 μm or less, and more preferably 12 μm or less. The lower limit value of the cycle length d is, for example, 6 μm.

により By setting the period length d to 20 μm or less, it is possible to suppress the occurrence of sparkle on the anti-glare surface 12a. In particular, when the cycle length d is 1/3 or less of the pixel size of the display device to which the transparent article 10 is applied, the generation of sparkle can be effectively suppressed. The pixel size of a display device having a pixel density of 420 ppi is 60 μm. The transparent article 10 preferably has a sparkle value described below of 0.006 to 0.02.

Next, the operation and effect of the present embodiment will be described.
(1) The transparent article 10 has an anti-glare surface 12a having an uneven structure. Relief structure antiglare surface 12a, the proportion of the higher slope angle of 5 ° in the slope angle distribution formed by the normal line n ₁ of the small plane dS in the normal n ₀ and anti-glare surface 12a of the anti-glare surface 12a is equal to or less than 45%.

According to the above configuration, the bright place contrast of the transparent article 10 can be increased.
(2) In the uneven structure of the anti-glare surface 12a, the period length d obtained from the autocorrelation function G _x (m) is 20 μm or less.

According to the above configuration, sparkle on the anti-glare surface 12a can be suppressed.
The present embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

The transparent article 10 may have other layers such as an antireflection layer and an antifouling layer in addition to the transparent substrate 11 and the antiglare layer 12.
The anti-glare surface 12 a is not limited to the surface of the anti-glare layer 12 provided on one main surface of the transparent substrate 11. For example, an anti-glare surface having a concavo-convex structure formed on the surface of the transparent substrate 11 by an anti-glare surface forming step using another method such as blasting or etching may be used.

The anti-glare surface 12 a may be provided on two or more surfaces of the transparent substrate 11.
Next, technical ideas that can be grasped from the above-described embodiment and modified examples will be described below.
(A) The transparent article used by being arranged on a display surface of a display device having a pixel density of 420 ppi or more.

(B) The transparent article in which the periodic length of the anti-glare surface of the transparent article is not more than 1/3 of the pixel size of the display device.

Hereinafter, the embodiment will be described more specifically with reference to test examples. Note that the present invention is not limited to these.
(Test Examples 1, 2, 4, 10)
Four types of glass articles having an anti-glare surface formed by an etching method and having different concavo-convex structures on the anti-glare surface were used as Test Examples 1, 2, 4, and 10, respectively. In Test Examples 1, 2, and 4, etching was performed using an HF aqueous solution, and in Test Example 10, etching was performed using an NH ₄ HF ₂ aqueous solution as an etchant.

(Test Examples 3, 5 to 9)
Transparent articles of Test Examples 3, 5 to 9 having different anti-glare surface irregularities were produced as follows.

A coating agent is applied to one surface of a transparent base material (manufactured by Nippon Electric Glass Co., Ltd .: T2X-1) made of 1.3 mm-thick plate-shaped chemically strengthened glass by a spray coating device. An anti-glare layer was formed. The nozzle of the spray coating device is a two-fluid nozzle, and the coating agent is a solution prepared by dissolving the precursor of the anti-glare layer (tetraethyl orthosilicate) in a liquid medium containing water. It was applied to a transparent substrate whose surface temperature was adjusted to a predetermined temperature at a flow rate of 0.3 kg / hour at a humidity of 52% and dried by heating at 180 ° C. for 30 minutes. As shown in Table 1, the transparent articles of Test Examples 3, 5 to 9 had a nozzle diameter, an atomizing air pressure for spraying a coating agent, and a unit area of the coating agent when forming an antiglare layer. By changing the coating amount and the surface temperature of the transparent substrate, the uneven structure of the anti-glare surface is changed.

(Analysis of uneven structure of anti-glare surface)
Using a laser microscope (VK-X250 manufactured by KEYENCE) that can measure with an XY resolution of 0.3 μm or less and a height resolution of 0.5 nm or less, the three-dimensional shape of the antiglare surface of Test Examples 1 to 10 under the following measurement conditions: Was measured.

Measurement range: 287 μm × 215 μm
Number of measurement points: 1024 x 768
Measurement point density: 12.7 Point / μm ²
Based on the obtained three-dimensional shape data, the surface roughness Ra and the gradient angle distribution of the gradient angle γ were obtained. Then, the ratio of the gradient angle of 5 ° or more was determined from the gradient angle distribution of the gradient angle γ. In addition, the autocorrelation function _Gx (m) was obtained from the measured three-dimensional shape, and the period length d was obtained from the autocorrelation function _Gx (m). The results are shown in Tables 2 and 3. FIGS. 3 and 4 show graphs of the gradient angle distribution of the gradient angle γ on the antiglare surface 12a of Test Example 3 and Test Example 10, and the integrated distribution thereof. FIG. 5 shows a graph of the autocorrelation function G _x (m) of the antiglare surface in Test Example 10.

(Evaluation of light place contrast)
Each transparent article was placed on the display surface of a display device (smartphone: H1512 manufactured by Huawei) with a pixel density of 515 ppi, with the side on which the anti-glare surface was formed facing upward. In a state where sunlight is incident on the display surface of the display device from a direction at an incident angle of 60 °, 10 panelists observe images on the display device from a direction at an observation angle of 20 ° to remove white blur. They were asked if they felt it. The results are shown in the "bright place contrast" column of Tables 2 and 3. In the “bright place contrast” column, “0” indicates that the number of persons who evaluated that white blur was felt is “３”, and “X” indicates that the number is 4 to 10.

(Measurement of sparkle value)
The sparkle value of the antiglare surface of the transparent article of each test example was measured. The results are shown in Tables 2 and 3. The sparkle value is determined by arranging a surface light source with a pattern mask interposed on the surface opposite to the anti-glare surface of the transparent article, and setting the anti-glare surface of the transparent article and the pattern mask within the front depth of field at an allowable confusion circle diameter of 53 μm. The top surface is included, the transparent article is imaged from the anti-glare side, and the standard deviation of the pixel brightness of the pattern mask obtained by analyzing the image data obtained by imaging is analyzed by analyzing the image data. This is a value obtained by dividing the average value of the pixel luminance of the pattern mask obtained by the above.

The sparkle value is a value indicating the degree of sparkle on the anti-glare surface. The more the sparkle on the anti-glare surface is suppressed, the lower the sparkle value. By using the sparkle value, it is possible to perform a quantitative evaluation of the sparkle that is close to image recognition based on human vision. Hereinafter, a specific method for measuring the sparkle value will be described.

As shown in FIG. 6, a pattern mask 21 of 500 ppi (pixel size 51 μm) is arranged on the surface light source 20, and a surface located on the side opposite to the anti-glare surface 12 a is placed on the pattern mask 21. The transparent article 10 was arranged so as to face the side. Further, on the anti-glare surface 12a side of the transparent article 10, a photodetector 22 having a permissible circle of confusion set to 53 μm was arranged. As the photodetector 22, SMS-1000 (manufactured by Display-Messtechnik & System) was used.

センサー The sensor size of the photodetector 22 is 1/3 type, and the pixel size is 3.75 μm × 3.75 μm. The focal length of the lens of the photodetector 22 is 100 mm, and the lens aperture diameter is 4.5 mm. The pattern mask 21 is arranged such that its top surface 21a is located at the focal position of the photodetector 22, and the transparent article 10 has a distance from the top surface 21a of the pattern mask 21 to the anti-glare surface 12a of 1.8 mm. Placed in position.

Next, with the anti-glare surface 12a of the transparent article 10 being irradiated with light from the surface light source 20 via the pattern mask 21, the transparent detector 10 is imaged by the photodetector 22, and the anti-glare surface of the transparent article 10 is imaged. Image data of the surface 12a was obtained. The obtained image data is analyzed by the sparkle measurement mode (software {Sparkle measurement} system) of the SMS-1000, and the pixel luminance of each pixel of the pattern mask 21, the standard deviation of the pixel luminance between pixels, and the average value of the pixel luminance I asked. The sparkle value was calculated by the following equation (3) based on the obtained standard deviation of pixel luminance between pixels and the average value of pixel luminance.

{Sparkle value = [standard deviation of pixel brightness of pattern mask] / [average value of pixel brightness of pattern mask]} (3)

As shown in Tables 2 and 3, in Test Examples 1 to 7 in which the ratio of the gradient angle of 5 ° or more was 45% or less, a result was obtained in which it was difficult to feel white blur. From this result, it can be seen that the contrast in the bright place is improved by using the anti-glare surface having the uneven structure in which the ratio of the gradient angle of 5 ° or more is 45% or less.

Further, in Test Examples 3, 5 to 10 in which the cycle length d was 20 μm or less, the sparkle value was lower than those in Test Examples 1, 2, and 4 in which the cycle length d exceeded 20 μm. From this result, it can be seen that sparkle can be suppressed by using an anti-glare surface having a concavo-convex structure having a period length d of 20 μm or less.

# 10: transparent article, 11: transparent substrate, 12: anti-glare layer, 12a: anti-glare surface.

Claims

A transparent article having an anti-glare surface having an uneven structure,
The transparent structure is characterized in that a ratio of a gradient angle of 5 ° or more in a gradient angle distribution formed by a normal line of the antiglare surface and a normal line of a minute plane in the antiglare surface is 45% or less. Goods.
The transparent article according to claim 1, further comprising a transparent substrate made of glass, and an anti-glare layer provided on the transparent substrate.