WO2015174132A1 - Method for evaluating optical characteristic of transparent substrate, and transparent substrate - Google Patents

Method for evaluating optical characteristic of transparent substrate, and transparent substrate Download PDF

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Publication number
WO2015174132A1
WO2015174132A1 PCT/JP2015/057694 JP2015057694W WO2015174132A1 WO 2015174132 A1 WO2015174132 A1 WO 2015174132A1 JP 2015057694 W JP2015057694 W JP 2015057694W WO 2015174132 A1 WO2015174132 A1 WO 2015174132A1
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Prior art keywords
transparent substrate
glare
index value
luminance distribution
antiglare
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PCT/JP2015/057694
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French (fr)
Japanese (ja)
Inventor
稔 玉田
裕介 小林
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旭硝子株式会社
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Application filed by 旭硝子株式会社 filed Critical 旭硝子株式会社
Priority to CN201580024709.8A priority Critical patent/CN106461502B/en
Priority to KR1020167031511A priority patent/KR102321551B1/en
Priority to JP2015540938A priority patent/JP6341210B2/en
Publication of WO2015174132A1 publication Critical patent/WO2015174132A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements

Definitions

  • the present invention relates to a method for evaluating the optical characteristics of a transparent substrate.
  • a protective cover made of a transparent substrate is disposed to protect the display device.
  • an antiglare treatment may be applied to the surface of the transparent substrate.
  • Patent Document 1 discloses a method for evaluating the reflection on a display device using a special device.
  • the transparent substrate is often subjected to an antiglare treatment.
  • the glare of the transparent substrate has a problem that it is difficult to say that an evaluation method has been sufficiently established so far, and it is difficult to quantitatively evaluate it.
  • SMS-1000 apparatus manufactured by Display-Messtechnik & System
  • glare of a transparent substrate can be evaluated by analyzing an image (luminance) of a part of the transparent substrate taken through a solid-state imaging device.
  • the present invention has been made in view of such a background, and the present invention provides an evaluation method capable of appropriately evaluating both the antiglare property and the glare of an antiglare-treated transparent substrate. Objective.
  • a method for evaluating the optical characteristics of a transparent substrate Obtaining a quantified anti-glare index value of a transparent substrate having first and second surfaces, the first surface being anti-glare treated; Obtaining a quantified glare index value of the transparent substrate;
  • the transparent substrate has first and second surfaces, and the first surface is antiglare treated.
  • the antiglare index value R is 0.4 or more
  • a transparent substrate is provided in which the glare index value G is 0.6 or less.
  • the surface of the transparent substrate subjected to the anti-glare treatment also has various forms. It is extremely difficult to uniformly evaluate the antiglare property and glare of such a transparent substrate having various surfaces using the same index.
  • an SMS-1000 apparatus has attracted attention as a transparent substrate glare evaluation apparatus.
  • the measurement result with the appropriate glare is often not obtained by the evaluation using the SMS-1000 apparatus. That is, even if the transparent substrate does not show significant glare by visual observation, the evaluation by the SMS-1000 apparatus determines that the transparent substrate shows a large glare and the opposite case. And exist.
  • the present invention is a method for evaluating the optical properties of a transparent substrate, Obtaining a quantified anti-glare index value of a transparent substrate having first and second surfaces, the first surface being anti-glare treated; Obtaining a quantified glare index value of the transparent substrate;
  • both the antiglare property and the glare of the transparent substrate treated with antiglare are properly evaluated regardless of the method of antiglare treatment. Is possible.
  • FIG. 1 schematically shows a flow of a method for evaluating the antiglare property of a transparent substrate according to an embodiment of the present invention.
  • the method for evaluating the antiglare property of the transparent substrate is: (A) The first light is irradiated from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 ° with respect to the thickness direction of the transparent substrate; Measuring the brightness of light regularly reflected on the surface (hereinafter also referred to as “20 ° specularly reflected light”) (step S110); (B) The light receiving angle of the reflected light reflected by the first surface is changed in a range of ⁇ 20 ° to + 60 °, and the first light reflected by the first surface (hereinafter referred to as “total reflected light”).
  • step S120 of measuring the luminance of (C) Step of calculating an antiglare index value R from the following equation (1) (step S130)
  • Anti-glare index value R (Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1) And having.
  • Step S110 First, a transparent substrate having first and second surfaces facing each other is prepared.
  • the transparent substrate may be made of any material as long as it is transparent.
  • the transparent substrate may be, for example, glass or plastic.
  • the composition of the glass is not particularly limited.
  • the glass may be, for example, soda lime glass or aluminosilicate glass.
  • the first and / or second surfaces may be chemically strengthened.
  • the chemical strengthening treatment means that a glass substrate is immersed in a molten salt containing an alkali metal, and an alkali metal (ion) having a small ionic radius existing on the outermost surface of the glass substrate is converted into an ionic radius existing in the molten salt.
  • This is a generic term for technologies that substitute for large alkali metals (ions).
  • an alkali metal (ion) having an ionic radius larger than that of the original atom is arranged on the surface of the treated glass substrate. For this reason, compressive stress can be given to the surface of a glass substrate, and the intensity
  • the glass substrate contains sodium ions (Na + )
  • the sodium ions are replaced with, for example, potassium ions (K + ) by the chemical strengthening treatment.
  • the lithium ions may be replaced with, for example, sodium ions (Na + ) and / or potassium ions (K + ) by chemical strengthening treatment.
  • the transparent substrate is made of plastic
  • the composition of the plastic is not particularly limited.
  • the transparent substrate may be a polycarbonate substrate, for example.
  • an anti-glare process is performed on the first surface of the transparent substrate.
  • the method of anti-glare processing is not particularly limited.
  • the anti-glare process may be, for example, a frost process, an etching process, a sand blast process, a lapping process, or a silica coat process.
  • anti-glare index value R a quantitative index value indicating the anti-glare property of the transparent substrate. Accordingly, various methods can be employed as the antiglare processing method.
  • the first surface of the transparent substrate after the antiglare treatment may have a surface roughness (arithmetic average roughness Ra) in the range of 0.05 ⁇ m to 1.0 ⁇ m, for example.
  • the first light is irradiated from the first surface side of the prepared transparent substrate toward the direction of 20 ° ⁇ 0.5 ° with respect to the thickness direction of the transparent substrate.
  • the first light is reflected from the first surface of the transparent substrate.
  • 20 ° specularly reflected light is received and the luminance is measured to obtain “the luminance of the 20 ° regular reflected light”.
  • Step S120 the light receiving angle of the reflected light reflected from the first surface is changed in the range of ⁇ 20 ° to + 60 °, and the same operation is performed. At this time, the luminance distribution of the first light reflected from the first surface of the transparent substrate and emitted from the first surface is measured and summed to obtain “the luminance of the total reflected light”.
  • FIG. 2 schematically shows an example of a measuring apparatus used when obtaining the antiglare index value R represented by the above-described formula (1).
  • the measuring apparatus 300 includes a light source 350 and a detector 370, and the transparent substrate 210 is disposed in the measuring apparatus 300.
  • the transparent substrate 210 has a first surface 212 and a second surface 214.
  • the light source 350 emits first light 362 toward the transparent substrate 210.
  • the detector 370 receives the reflected light 364 reflected on the first surface 212 and detects its brightness.
  • the transparent substrate 210 is disposed so that the first surface 212 is on the light source 350 and the detector 370 side. Accordingly, the first light detected by the detector 370 is reflected light 364 reflected by the transparent substrate 210.
  • the surface subjected to the antiglare treatment becomes the first surface 212 of the transparent substrate 210. That is, in this case, the transparent substrate 210 is disposed in the measurement apparatus 300 such that the antiglare-treated surface is on the light source 350 and the detector 370 side.
  • the first light 362 is irradiated at an angle inclined by 20 ° with respect to the thickness direction of the transparent substrate 210.
  • a range of 20 ° ⁇ 0.5 ° is defined as an angle of 20 ° in consideration of an error of the measuring apparatus.
  • the first light 362 is irradiated from the light source 350 toward the transparent substrate 210, and the detector 370 disposed so that the light receiving angle ⁇ is 20 ° is used. Specular light 364 reflected by the first surface 212 is detected. Thereby, “20 ° specularly reflected light” is detected.
  • the light receiving angle ⁇ for measuring the reflected light 364 is changed in the range of ⁇ 20 ° to + 60 °, and the same operation is performed.
  • minus ( ⁇ ) of the light receiving angle ⁇ represents that the light receiving angle is on the incident light side with respect to the normal line of the target surface to be evaluated (first surface in the above example), and plus ( (+) Indicates that the light receiving angle is not on the incident light side compared to the normal of the target surface.
  • the antiglare index value R of the transparent substrate 210 can be obtained from the brightness of the obtained 20 ° specularly reflected light and the brightness of the totally reflected light by the above-described formula (1). Such a measurement can be easily performed by using a commercially available goniometer (variable photometer).
  • the irradiation angle of the first light can be appropriately selected from the range of 60 ° to 5 °. However, in the present application, 20 ° is selected as the irradiation angle of the first light from the viewpoint that the anti-glare evaluation and the quantitative evaluation by visual observation show a good correlation.
  • FIG. 3 schematically shows a flow of a method for evaluating glare of a transparent substrate according to an embodiment of the present invention.
  • a method for evaluating the glare of the transparent substrate (hereinafter, also referred to as “second method”) (A) disposing a transparent substrate having first and second surfaces on the display device such that the second surface is on the display device side (step S210); (B) A step of photographing the transparent substrate using a solid-state imaging device and obtaining a first image with the display device turned on, and a distance between the solid-state imaging device and the transparent substrate.
  • Step S210 First, a transparent substrate having first and second surfaces facing each other is prepared.
  • the transparent substrate is antiglare treated on the first surface.
  • the material, composition, etc. of the transparent substrate are the same as those shown in step S110 described above, and will not be described further here.
  • the glare of a transparent substrate having various surfaces that differ according to a plurality of anti-glare treatment methods as well as between conventional single anti-glare treatment methods, such as a change in conditions in an etching process. It was difficult to uniformly evaluate with the same index.
  • the glare evaluation method according to an embodiment of the present invention as described below, various transparent substrates are uniformly used by using a quantitative index value (glaring index value G) indicating the glare of the transparent substrate. It can be evaluated. Therefore, it should be noted that the glare evaluation method according to an embodiment of the present invention is also useful as a means for selecting a processing method for anti-glare processing.
  • the display device is not particularly limited as long as it has a picture element (pixel).
  • the display device may be, for example, an LCD device, an OLED (Organic Light Emitting Diode) device, a PDP (Plasma Display Panel) device, or a tablet display device.
  • the resolution of the display device is, for example, preferably 132 ppi or more, more preferably 186 ppi or more, and further preferably 264 ppi or more.
  • a transparent substrate is disposed on the display device.
  • the transparent substrate is disposed on the display device such that the second surface is on the display device side.
  • Step S220 Next, in a state where the display device is turned on (that is, a state where an image is displayed), the transparent substrate is photographed from the first surface side using the solid-state imaging device, and the transparent substrate disposed on the display device is An image (first image) is acquired.
  • the distance d between the solid-state imaging device and the transparent substrate is set to a predetermined value.
  • a distance index r is used as an index corresponding to the distance d between the solid-state imaging device and the transparent substrate.
  • the distance index r is expressed by the following formula (4) using the focal length f of the solid-state imaging device and the distance d between the solid-state imaging device and the transparent substrate:
  • Distance index r (distance d between solid-state imaging device and transparent substrate) / (Focal distance f of solid-state image sensor) Formula (4)
  • the distance index r is 8 or more.
  • the distance index r is smaller than 8
  • the distance d between the solid-state imaging device and the transparent substrate becomes small, and is easily affected by the form of the first surface of the transparent substrate subjected to the antiglare treatment. . Therefore, by setting the distance index r to 8 or more, the transparent substrate that has been anti-glare treated by various methods in a state where the influence of the difference in the shape of the first surface due to the difference in the applied anti-glare treatment method is significantly suppressed. It is possible to uniformly evaluate glare.
  • the distance index r is preferably 9 or more, and more preferably 10 or more.
  • the image displayed on the display device is a single color (for example, green) image, and is preferably displayed on the entire display screen of the display device. This is for minimizing the influence of differences in appearance due to differences in display colors.
  • CMOS complementary metal oxide semiconductor
  • a first image 410 as schematically shown in FIG. 4 is obtained.
  • a region corresponding to nine pixels arranged in 3 rows ⁇ 3 columns of a part of the display device hereinafter referred to as corresponding regions 420-1 to 420-9). ) Is brightly visible.
  • the corresponding areas 420-1 to 420-9 are shown in a sufficiently separated state.
  • the distance between the corresponding areas 420-1 to 420-9 is narrower, and the bright portions may partially overlap between the adjacent corresponding areas.
  • Step S230 Next, the first image 410 captured in step S220 is subjected to image analysis, and a first luminance distribution is formed.
  • the first luminance distribution is formed as a three-dimensional map on the XY plane.
  • FIG. 5 schematically shows an example of the first luminance distribution obtained in this step.
  • the first luminance distribution 430 includes luminance distribution components q 1 to q having a substantially normal distribution shape in the areas corresponding to the corresponding areas 420-1 to 420-9 of the first image 410, respectively. with a q 9. More generally, the first luminance distribution 430 is represented by a set of i plural luminance distribution components q i (i is an integer of 2 or more).
  • the luminance distribution components q 1 to q 9 are shown two-dimensionally (that is, non-stereoscopically) in order to avoid complicated description.
  • the number of the first images 410 to be photographed is increased in step S220, and in this step S230, the same image analysis is performed for each first image 410. May be implemented.
  • the first luminance distribution 430 with higher accuracy can be obtained by averaging the image analysis results thereafter.
  • Step S240 Next, the transparent substrate is slid in a direction parallel to the second surface, and the transparent substrate is moved relative to the display device.
  • the moving distance is preferably less than 10 mm, and may be several mm, for example.
  • Step S250 Next, steps S220 to S230 are repeated. That is, while the display device is turned on, the second image is acquired by the solid-state imaging device, and the second luminance distribution is formed from the second image.
  • the number of second images taken by the solid-state imaging device may be increased in order to increase the accuracy of the second luminance distribution. Thereafter, image analysis is performed on each second image, and each image analysis result is averaged to obtain a second luminance distribution with higher accuracy.
  • a second luminance distribution represented by a collection of a plurality of luminance distribution components s i (where i is an integer of 2 or more) is obtained.
  • the luminance distribution components si are configured with the same number as the luminance distribution components qi.
  • the difference luminance distribution ⁇ S is calculated from the difference between the first luminance distribution and the second luminance distribution. Similar to the first luminance distribution and the second luminance distribution, the difference luminance distribution ⁇ S is represented by a collection of luminance distribution components t i (where i is an integer of 2 or more) having a substantially normal distribution shape.
  • Step S270 Next, the average luminance distribution ⁇ S ave and the variance ⁇ are calculated using the difference luminance distribution ⁇ S obtained in step S260.
  • the average luminance distribution ⁇ S ave can be obtained by averaging the absolute values of i luminance distribution components t i included in the difference luminance distribution ⁇ S.
  • the variance ⁇ can be obtained from the following equation (5) using i luminance distribution components t i included in the difference luminance distribution ⁇ S and the average luminance distribution ⁇ S ave .
  • the output value A is calculated by the following equation (2).
  • Output value A dispersion ⁇ / average luminance distribution ⁇ S ave equation (2) (Step S280)
  • the above-described steps S210 to S270 are carried out using a reference (reference) anti-glare-treated transparent substrate.
  • the reference output value Q is obtained instead of the output value A in the equation (2).
  • the reference output value Q is strongly required to be reproducible in measurement and is sufficiently larger than the error for each measurement. Is needed.
  • soda lime glass is a flat glass that has been anti-glare treated by frost etching, and has a gloss value of 60 degrees. Is as large as possible, and the average length RSm of the roughness curve elements is 70 ⁇ m or more and less than 120 ⁇ m, and a commercially available product may be selected.
  • the 60 degree gloss value can be measured as the specular gloss by a method based on JIS-Z8741.
  • the 60 degree gloss value is, for example, 110 or more, and more preferably 120 or more.
  • the average length RSm of the roughness curve element can be measured by a method based on JIS B0601 (2001).
  • the average length RSm of the roughness curve element is, for example, 70 ⁇ m or more, more preferably 80 ⁇ m or more, and less than 120 ⁇ m, preferably less than 110 ⁇ m.
  • the reference antiglare-treated transparent substrate that satisfies the above conditions has a 60-degree gloss value of 140% and an average length RSm of the surface roughness curve element of 85 ⁇ m.
  • VRD140 anti-glare treated glass manufactured by Asahi Glass Co., Ltd. was selected.
  • this step S280 may be performed before performing the above-described steps S210 to S270 using a transparent substrate subjected to an anti-glare process for evaluation.
  • this step S280 may be performed in parallel with the execution of steps S210 to S270 on the anti-glare-treated transparent substrate for evaluation.
  • the glare index value G correlates with the visual judgment result of the glare by the observer and shows a behavior close to human visual perception.
  • a transparent substrate with a large glare index value G has noticeable glare, and conversely, a transparent substrate with a small glare index value G tends to suppress glare. Therefore, the glare index value G can be used as a quantitative index when judging the glare of the transparent substrate.
  • the method for evaluating the glare of the transparent substrate has been described above with reference to FIGS.
  • the method for evaluating the glare of the transparent substrate is not limited to this.
  • a step (step S265) of removing a component derived from the display device from the difference luminance distribution ⁇ S may be performed between step S260 and step S270.
  • a step S265 of removing a component derived from the display device from the difference luminance distribution ⁇ S may be performed between step S260 and step S270.
  • the differential luminance distribution [Delta] S instead of the differential luminance distribution [Delta] S, using the effective difference luminance distribution [Delta] S e obtained by this operation, by performing the step S270, it is possible to further improve the accuracy of the glare index value G obtained.
  • this step S265 may be performed when necessary, and is not necessarily performed.
  • the method for evaluating the glare of the transparent substrate described above can be easily performed by using, for example, an SMS-1000 apparatus (manufactured by Display-Messtechnik & System).
  • FIG. 6 shows an example of a graph plotting the relationship between the antiglare index value R (horizontal axis) and the glare index value G (vertical axis) obtained in a transparent substrate that has been antiglare treated by various methods.
  • the distance index r at the time of shooting in the glare evaluation for acquiring this data is 10.8.
  • an ideal transparent substrate region having both good anti-glare properties and good anti-glare properties is indicated by a symbol “ideal”.
  • the transparent substrate included in the region C indicated by hatching in FIG. Will be selected uniformly. That is, in such a method, a transparent substrate with poor antiglare properties is included in the selection candidate transparent substrate.
  • the transparent substrate included in the region D indicated by hatching in FIG. 6 is uniformly selected, and a transparent substrate with poor glare prevention property is selected. It will be included in the selection candidates.
  • the transparent substrate can be appropriately selected according to the purpose and application, that is, the best characteristics can be exhibited in terms of glare prevention and antiglare properties.
  • a transparent substrate can be selected.
  • two optical characteristics can be considered quantitatively at a time, so that a transparent substrate can be selected more appropriately according to the purpose of use and application. It becomes.
  • FIG. 7 schematically shows a transparent substrate (hereinafter simply referred to as “transparent substrate”) 900 according to an embodiment of the present invention.
  • the transparent substrate 900 is made of glass.
  • the composition of the glass is not particularly limited, and the glass may be, for example, soda lime glass or aluminosilicate glass.
  • the transparent substrate 900 has a first surface 902 and a second surface 904, and the first surface 902 is antiglare-treated.
  • the anti-glare treatment method is not particularly limited.
  • the anti-glare process may be, for example, a frost process, an etching process, a sand blast process, a lapping process, or a silica coat process.
  • the first surface 902 of the transparent substrate may have a surface roughness (arithmetic average roughness Ra) in the range of 0.05 ⁇ m to 1.0 ⁇ m, for example.
  • the first surface 902 and / or the second surface 904 may be chemically strengthened.
  • the dimensions and shape of the transparent substrate 900 are not particularly limited.
  • the transparent substrate 900 may have a square shape, a rectangular shape, a circular shape, an elliptical shape, or the like.
  • the transparent substrate 900 is preferably thin.
  • the thickness of the transparent substrate 900 may be in the range of 0.2 mm to 2.0 mm.
  • the transparent substrate 900 has a feature that the antiglare index value R measured by using the first method (step S110 to step S130) is 0.4 or more.
  • the antiglare index value R is preferably 0.6 or more, and more preferably 0.8 or more.
  • the glare index value G is preferably 0.5 or less, more preferably 0.4 or less, and further preferably 0.3 or less.
  • a frost treatment As the antiglare treatment, a frost treatment, an etching treatment, a sand blast treatment, a lapping treatment, or a silica coating treatment was adopted.
  • aluminosilicate glass was used for the transparent substrate.
  • each transparent substrate was visually observed from the first surface (that is, antiglare-treated surface) side, and antiglare property was evaluated in 12 stages from level 1 to level 12.
  • the observation direction was 20 ° with respect to the thickness direction of the transparent substrate.
  • Steps S110 to S130 described above are performed, and the formula (1) is used to prevent each transparent substrate.
  • the dazzling index value R was calculated.
  • FIG. 8 shows an example of the relationship between the visually evaluated antiglare evaluation level (vertical axis) and the antiglare index value R (horizontal axis) obtained for each transparent substrate.
  • FIG. 8 shows that there is a positive correlation between the two.
  • the anti-glare index value R corresponds to the tendency of the evaluation level of the reflected image diffusivity visually observed by the observer, and therefore the anti-glare index value R can be used to determine the reflected image diffusivity of the transparent substrate.
  • the antiglare index value R it can be said that the reflected image diffusibility of the transparent substrate can be objectively and quantitatively determined.
  • each transparent substrate is directly arranged on a display device (iPad (registered trademark), resolution 264 ppi).
  • the transparent substrate was placed on the display device such that the first surface of each transparent substrate (that is, the antiglare-treated surface) was on the viewer side.
  • the image displayed from the display device was a green monochromatic image, and the size of the image was 19.6 cm ⁇ 14.6 cm.
  • each transparent substrate was visually observed from the first surface side, and glare was evaluated in 11 stages from level 0 to level 10.
  • Level 0 represents little glare
  • level 10 represents very significant glare. Further, the level value during this time tends to increase the glare as the numerical value increases.
  • FIG. 9 shows an example of the relationship between the glare index value G (vertical axis) and the visual glare level (horizontal axis) obtained for each transparent substrate.
  • FIG. 9 shows that there is a positive correlation between the two.
  • the glare index value G corresponds to the tendency of the determination result of the glare visually observed by the observer, and therefore the glare index value G can be used to determine the glare of the transparent substrate.
  • the glare of the transparent substrate can be objectively and quantitatively determined by using the glare index value G.
  • the antiglare index value R and the glare index value G can be used as quantitative indexes for the antiglare property and the glare of the transparent substrate, respectively.
  • the present invention can be used for optical characteristic evaluation of a transparent substrate installed in various display devices such as an LCD device, an OLED device, a PDP device, and a tablet display device.

Abstract

　A method for evaluating an optical characteristic of a transparent substrate, the method having, in any order, a step for ascertaining an antiglare index value (R) quantified for a transparent substrate subjected to an antiglare treatment, and a step for ascertaining a glare index value (G) quantified for the transparent substrate.

Description

透明基体の光学特性を評価する方法および透明基体Method for evaluating optical properties of transparent substrate and transparent substrate
　本発明は、透明基体の光学特性を評価する方法に関する。 The present invention relates to a method for evaluating the optical characteristics of a transparent substrate.
　一般に、画素を有するＬＣＤ（Ｌｉｑｕｉｄ　Ｃｒｙｓｔａｌ　Ｄｉｓｐｌａｙ）装置のような表示装置の上には、該表示装置の保護のため、透明基体で構成された保護カバーが配置される。 Generally, on a display device such as an LCD (Liquid Crystal Display) device having pixels, a protective cover made of a transparent substrate is disposed to protect the display device.
　しかしながら、表示装置上にこのような透明基体を設置した場合、透明基体を介して表示装置の表示画を視認しようとした際に、しばしば、周辺に置かれているものの映り込みが生じる場合がある。透明基体にそのような映り込みが生じると、表示画の視認者は、表示画を視認することが難しくなる上、不快な印象を受けるようになる。 However, when such a transparent substrate is installed on the display device, when an attempt is made to visually recognize a display image on the display device through the transparent substrate, reflection of what is placed in the vicinity often occurs. . When such a reflection is generated on the transparent substrate, it becomes difficult for a viewer of the display image to visually recognize the display image and an unpleasant impression.
　そこで、このような映り込みを抑制するため、透明基体の表面に対して、アンチグレア処理が適用される場合がある。 Therefore, in order to suppress such reflection, an antiglare treatment may be applied to the surface of the transparent substrate.
　なお、特許文献１には、特殊な装置を用いて、表示装置への映り込みを評価する方法が示されている。 Note that Patent Document 1 discloses a method for evaluating the reflection on a display device using a special device.
特開２００７－１４７３４３号公報JP 2007-147343 A
　前述のように、周囲光の映り込みを抑制するため、透明基体には、しばしば、アンチグレア処理が実施される。 As described above, in order to suppress the reflection of ambient light, the transparent substrate is often subjected to an antiglare treatment.
　ところで、実際の透明基体では、周囲光の映り込みの抑制効果の他、防眩性およびぎらつきなどの特性も同時に把握したい場合がある。 By the way, in an actual transparent substrate, in addition to the effect of suppressing the reflection of ambient light, there are cases where it is desired to simultaneously grasp characteristics such as anti-glare properties and glare.
　しかしながら、これまで、透明基体の防眩性とぎらつきの両方を評価する方法は、あまり知られていない。特に、透明基体のぎらつきについては、これまでに評価手法が十分に確立しているとは言い難く、定量的に評価すること自体が難しいという問題がある。 However, so far, there is not much known a method for evaluating both the antiglare property and the glare of the transparent substrate. In particular, the glare of the transparent substrate has a problem that it is difficult to say that an evaluation method has been sufficiently established so far, and it is difficult to quantitatively evaluate it.
　なお、透明基体のぎらつき評価装置として、最近、ＳＭＳ－１０００装置（Ｄｉｓｐｌａｙ－Ｍｅｓｓｔｅｃｈｎｉｋ＆Ｓｙｓｔｅｍｅ社製）が注目されている。このＳＭＳ－１０００装置では、固体撮像素子を介して撮影された透明基体の一部の画像（輝度）の解析により、透明基体のぎらつきを評価できる。 Note that an SMS-1000 apparatus (manufactured by Display-Messtechnik & System) has recently attracted attention as an apparatus for evaluating glare of a transparent substrate. In this SMS-1000 apparatus, glare of a transparent substrate can be evaluated by analyzing an image (luminance) of a part of the transparent substrate taken through a solid-state imaging device.
　しかしながら、本願発明者らの知見によれば、ＳＭＳ－１０００装置による評価では、しばしば、適正なぎらつきの測定結果が得られないことが認められている。すなわち、目視観察では、有意なぎらつきが認められないものの、ＳＭＳ－１０００装置による評価では、透明基体が顕著なぎらつきを示すと判断される場合と、その逆の結果が生じる場合とが存在する。 However, according to the knowledge of the inventors of the present application, it has been recognized that the measurement result of the appropriate glare is often not obtained by the evaluation using the SMS-1000 apparatus. That is, no significant glare is recognized by visual observation, but there are cases where the transparent substrate is judged to show a noticeable glare and the opposite result occurs in the evaluation by the SMS-1000 apparatus.
　このように、現在も、透明基体の防眩性およびぎらつきの両方を適正に把握する技術が必要となっている。 As described above, there is still a need for a technique for properly grasping both the antiglare property and the glare of the transparent substrate.
　本発明は、このような背景に鑑みなされたものであり、本発明では、アンチグレア処理された透明基体の防眩性およびぎらつきの両方を適正に評価することが可能な評価方法を提供することを目的とする。 The present invention has been made in view of such a background, and the present invention provides an evaluation method capable of appropriately evaluating both the antiglare property and the glare of an antiglare-treated transparent substrate. Objective.
　本発明では、透明基体の光学特性を評価する方法であって、
　第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体の定量化された防眩性指標値を取得するステップと、
　前記透明基体の定量化されたぎらつき指標値を取得するステップと、
　を順不同に有し、
　前記定量化された防眩性指標値は、
　　（ａ）第１および第２の表面を有する透明基体の前記第１の表面側から、前記透明基体の厚さ方向に対して２０゜の方向に第１の光を照射し、前記第１の表面で反射する２０゜正反射光の輝度を測定するステップと、
　　（ｂ）前記第１の表面により反射される反射光の受光角度を－２０゜～＋６０°の範囲で変化させ、前記第１の表面で反射される全反射光の輝度を測定するステップと、
　　（ｃ）以下の式（１）から、防眩性指標値Ｒを算定するステップと
 
　　防眩性指標値Ｒ＝
　　　　（全反射光の輝度－２０゜正反射光の輝度）／（全反射光の輝度）　　式（１）
 
　により得られ、
　前記定量化されたぎらつき指標値は、
　　（Ａ）前記透明基体を、前記第２の表面が表示装置の側になるようにして、前記表示装置の上に配置するステップと、
　　（Ｂ）前記表示装置をオンにした状態で、固体撮像素子を用いて前記透明基体を撮影し、第１の画像を取得するステップであって、前記固体撮像素子と前記透明基体の間の距離をｄとし、前記固体撮像素子の焦点距離をｆとしたとき、撮影の際の距離指数ｒ（＝ｄ／ｆ）は、８以上であるステップと、
　　（Ｃ）前記取得された第１の画像から、第１の輝度分布を形成するステップと、
　　（Ｄ）前記透明基体を、前記第２の表面と略平行な方向に動かし、前記透明基体を前記表示装置に対して移動させるステップと、
　　（Ｅ）前記（Ｂ）および（Ｃ）のステップを繰り返し、取得された第２の画像から、第２の輝度分布を形成するステップと、
　　（Ｆ）前記第１の輝度分布と前記第２の輝度分布の差分から、差分輝度分布ΔＳを求めるステップと、
　　（Ｇ）前記差分輝度分布ΔＳから、平均輝度分布ΔＳａｖｅおよび分散σを算定するとともに、以下の式（２）から、出力値Ａを得るステップと、
 
　　出力値Ａ＝分散σ／平均輝度分布ΔＳａｖｅ　　式（２）
 
　　（Ｈ）前記（Ａ）～（Ｇ）のステップを、基準用のアンチグレア処理された透明基体で実施して、出力値Ａの代わりに、参照出力値Ｑを得るステップであって、該（Ｈ）のステップは、前記（Ａ）～（Ｇ）のステップの前、または前記（Ａ）～（Ｇ）のステップと並列に実施されるステップと、
　　（Ｉ）以下の式（３）から、ぎらつき指標値Ｇを求めるステップと、
 
　　ぎらつき指標値Ｇ＝（出力値Ａ）／（参照出力値Ｑ）　　　式（３）
 
　により得られることを特徴とする方法が提供される。 In the present invention, a method for evaluating the optical characteristics of a transparent substrate,
Obtaining a quantified anti-glare index value of a transparent substrate having first and second surfaces, the first surface being anti-glare treated;
Obtaining a quantified glare index value of the transparent substrate;
In random order,
The quantified anti-glare index value is
(A) The first light is irradiated from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 ° with respect to the thickness direction of the transparent substrate; Measuring the brightness of the 20 ° specularly reflected light reflected from the surface;
(B) changing the light receiving angle of the reflected light reflected by the first surface in a range of −20 ° to + 60 ° and measuring the luminance of the total reflected light reflected by the first surface;
(C) calculating the antiglare index value R from the following equation (1);
Anti-glare index value R =
(Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1)

Obtained by
The quantified glare index value is
(A) placing the transparent substrate on the display device with the second surface facing the display device;
(B) A step of photographing the transparent substrate using a solid-state imaging device and obtaining a first image with the display device turned on, and a distance between the solid-state imaging device and the transparent substrate. Where d is the distance index r (= d / f) at the time of shooting, where d is the focal length of the solid-state imaging device, and f is
(C) forming a first luminance distribution from the acquired first image;
(D) moving the transparent substrate in a direction substantially parallel to the second surface, and moving the transparent substrate with respect to the display device;
(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image;
(F) obtaining a difference luminance distribution ΔS from a difference between the first luminance distribution and the second luminance distribution;
(G) calculating an average luminance distribution ΔS ave and variance σ from the difference luminance distribution ΔS, and obtaining an output value A from the following equation (2):

Output value A = dispersion σ / average luminance distribution ΔS ave equation (2)

(H) Steps (A) to (G) are performed on a reference anti-glare transparent substrate to obtain a reference output value Q instead of the output value A. ) Is performed before the steps (A) to (G) or in parallel with the steps (A) to (G).
(I) A step of obtaining a glare index value G from the following equation (3):

Glitter index value G = (output value A) / (reference output value Q) Equation (3)

Is provided.
　また、本発明では、第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体であって、
　前述の本発明による方法で評価した際に、
　前記防眩性指標値Ｒが０．４以上であり、
　前記ぎらつき指標値Ｇが０．６以下であることを特徴とする透明基体が提供される。 In the present invention, the transparent substrate has first and second surfaces, and the first surface is antiglare treated.
When evaluated by the method according to the present invention described above,
The antiglare index value R is 0.4 or more,
A transparent substrate is provided in which the glare index value G is 0.6 or less.
　本発明では、アンチグレア処理された透明基体の防眩性およびぎらつきの両方を適正に評価することが可能な評価方法を提供できる。 In the present invention, it is possible to provide an evaluation method capable of appropriately evaluating both the antiglare property and the glare of the transparent substrate subjected to the antiglare treatment.
本発明の一実施形態による透明基体の防眩性を評価する方法のフローを概略的に示した図である。It is the figure which showed roughly the flow of the method of evaluating the glare-proof property of the transparent base | substrate by one Embodiment of this invention. 防眩性指標値を取得する際に使用される、測定装置の一例を模式的に示した図である。It is the figure which showed typically an example of the measuring apparatus used when acquiring an anti-glare index value. 本発明の一実施形態による透明基体のぎらつきを評価する方法のフローを概略的に示した図である。It is the figure which showed schematically the flow of the method of evaluating the glare of the transparent base | substrate by one Embodiment of this invention. 透明基体のぎらつきを評価する方法の一工程において得られた、第１の画像を模式的に示した図である。It is the figure which showed typically the 1st image obtained in 1 process of the method of evaluating the glare of a transparent base | substrate. 透明基体のぎらつきを評価する方法の一工程において得られた、第１の輝度分布を模式的に示した図である。It is the figure which showed typically the 1st luminance distribution obtained in 1 process of the method of evaluating the glare of a transparent base | substrate. 各種透明基体において得られた、防眩性指標値Ｒ（横軸）とぎらつき指標値Ｇ（縦軸）との関係の一例をプロットした図である。It is the figure which plotted an example of the relationship between the glare-proof index value R (horizontal axis) and the glare index value G (vertical axis) obtained in various transparent bases. 本発明の一実施形態による透明基体を模式的に示した図である。It is the figure which showed typically the transparent base | substrate by one Embodiment of this invention. 各透明基体において得られた、目視による防眩性のレベル（縦軸）と、防眩性指標値Ｒ（横軸）の間の関係の一例を示したグラフである。It is the graph which showed an example of the relationship between the level of anti-glare property by visual observation (vertical axis) and anti-glare index value R (horizontal axis) obtained in each transparent substrate. 各透明基体において得られた、ぎらつき指標値Ｇ（縦軸）と、目視によるぎらつきのレベル（横軸）の間の関係の一例を示したグラフである。It is the graph which showed an example of the relationship between the glare index value G (vertical axis) and the visual glare level (horizontal axis) obtained in each transparent substrate.
　以下、本発明について詳しく説明する。 Hereinafter, the present invention will be described in detail.
　前述のように、アンチグレア処理された透明基体において、防眩性とぎらつきの両特性を把握したい場合がある。しかしながら、現状では、透明基体の防眩性とぎらつきの両方を、客観的に評価できる方法はほとんど認められない。 As described above, there are cases where it is desired to grasp both the anti-glare property and the glare characteristics in the anti-glare-treated transparent substrate. However, at present, there are few methods that can objectively evaluate both the antiglare property and the glare of the transparent substrate.
　特に、透明基体にアンチグレア処理を施工する手段としては、様々な方法が存在するため、アンチグレア処理された透明基体の表面も、様々な形態のものが存在する。このような様々な表面を有する透明基体の防眩性およびぎらつきを、同じ指標で一律に評価することは極めて難しい。 Particularly, since various methods exist as means for applying the anti-glare treatment to the transparent substrate, the surface of the transparent substrate subjected to the anti-glare treatment also has various forms. It is extremely difficult to uniformly evaluate the antiglare property and glare of such a transparent substrate having various surfaces using the same index.
　例えば、最近、透明基体のぎらつき評価装置として、ＳＭＳ－１０００装置が注目されている。しかしながら、本願発明者らの知見によれば、ＳＭＳ－１０００装置による評価では、しばしば、適正なぎらつきの測定結果が得られないことが認められている。すなわち、目視観察では、有意なぎらつきが認められない透明基体であっても、ＳＭＳ－１０００装置による評価では、透明基体が大きなぎらつきを示すと判断される場合と、その逆の結果が生じる場合とが存在する。 For example, recently, an SMS-1000 apparatus has attracted attention as a transparent substrate glare evaluation apparatus. However, according to the knowledge of the inventors of the present application, it is recognized that the measurement result with the appropriate glare is often not obtained by the evaluation using the SMS-1000 apparatus. That is, even if the transparent substrate does not show significant glare by visual observation, the evaluation by the SMS-1000 apparatus determines that the transparent substrate shows a large glare and the opposite case. And exist.
　このように、透明基体のぎらつきにのみ着目しても、未だ十分に有効な測定手法が確立されているとは言い難い。さらに、透明基体の防眩性とぎらつきの両方に着目した評価手法に関しては、ほとんど存在しないのが実情である。 Thus, even if attention is paid only to the glare of the transparent substrate, it is still difficult to say that a sufficiently effective measurement technique has been established. Furthermore, there is almost no actual evaluation method that focuses on both the antiglare property and glare of the transparent substrate.
　これに対して、本発明では、透明基体の光学特性を評価する方法であって、
　第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体の定量化された防眩性指標値を取得するステップと、
　前記透明基体の定量化されたぎらつき指標値を取得するステップと、
　を順不同に有し、
　前記定量化された防眩性指標値は、
　　（ａ）第１および第２の表面を有する透明基体の前記第１の表面側から、前記透明基体の厚さ方向に対して２０゜の方向に第１の光を照射し、前記第１の表面で反射する２０゜正反射光の輝度を測定するステップと、
　　（ｂ）前記第１の表面により反射される反射光の受光角度を－２０゜～＋６０°の範囲で変化させ、前記第１の表面で反射される全反射光の輝度を測定するステップと、
　　（ｃ）以下の式（１）から、防眩性指標値Ｒを算定するステップと
 
　　防眩性指標値Ｒ＝
　　　　（全反射光の輝度－２０゜正反射光の輝度）／（全反射光の輝度）　　式（１）
 
　により得られ、
　前記定量化されたぎらつき指標値は、
　　（Ａ）前記透明基体を、前記第２の表面が表示装置の側になるようにして、前記表示装置の上に配置するステップと、
　　（Ｂ）前記表示装置をオンにした状態で、固体撮像素子を用いて前記透明基体を撮影し、第１の画像を取得するステップであって、前記固体撮像素子と前記透明基体の間の距離をｄとし、前記固体撮像素子の焦点距離をｆとしたとき、撮影の際の距離指数ｒ（＝ｄ／ｆ）は、８以上であるステップと、
　　（Ｃ）前記取得された第１の画像から、第１の輝度分布を形成するステップと、
　　（Ｄ）前記透明基体を、前記第２の表面と略平行な方向に動かし、前記透明基体を前記表示装置に対して移動させるステップと、
　　（Ｅ）前記（Ｂ）および（Ｃ）のステップを繰り返し、取得された第２の画像から、第２の輝度分布を形成するステップと、
　　（Ｆ）前記第１の輝度分布と前記第２の輝度分布の差分から、差分輝度分布ΔＳを求めるステップと、
　　（Ｇ）前記差分輝度分布ΔＳから、平均輝度分布ΔＳａｖｅおよび分散σを算定するとともに、以下の式（２）から、出力値Ａを得るステップと、
 
　　出力値Ａ＝分散σ／平均輝度分布ΔＳａｖｅ　　式（２）
 
　　（Ｈ）前記（Ａ）～（Ｇ）のステップを、基準用のアンチグレア処理された透明基体で実施して、出力値Ａの代わりに、参照出力値Ｑを得るステップであって、該（Ｈ）のステップは、前記（Ａ）～（Ｇ）のステップの前、または前記（Ａ）～（Ｇ）のステップと並列に実施されるステップと、
　　（Ｉ）以下の式（３）から、ぎらつき指標値Ｇを求めるステップと、
 
　　ぎらつき指標値Ｇ＝（出力値Ａ）／（参照出力値Ｑ）　　　式（３）
 
　により得られることを特徴とする方法が提供される。 In contrast, the present invention is a method for evaluating the optical properties of a transparent substrate,
Obtaining a quantified anti-glare index value of a transparent substrate having first and second surfaces, the first surface being anti-glare treated;
Obtaining a quantified glare index value of the transparent substrate;
In random order,
The quantified anti-glare index value is
(A) The first light is irradiated from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 ° with respect to the thickness direction of the transparent substrate; Measuring the brightness of the 20 ° specularly reflected light reflected from the surface;
(B) changing the light receiving angle of the reflected light reflected by the first surface in a range of −20 ° to + 60 ° and measuring the luminance of the total reflected light reflected by the first surface;
(C) calculating the antiglare index value R from the following equation (1);
Anti-glare index value R =
(Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1)

Obtained by
The quantified glare index value is
(A) placing the transparent substrate on the display device with the second surface facing the display device;
(B) A step of photographing the transparent substrate using a solid-state imaging device and obtaining a first image with the display device turned on, and a distance between the solid-state imaging device and the transparent substrate. Where d is the distance index r (= d / f) at the time of shooting, where d is the focal length of the solid-state imaging device, and f is
(C) forming a first luminance distribution from the acquired first image;
(D) moving the transparent substrate in a direction substantially parallel to the second surface, and moving the transparent substrate with respect to the display device;
(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image;
(F) obtaining a difference luminance distribution ΔS from a difference between the first luminance distribution and the second luminance distribution;
(G) calculating an average luminance distribution ΔS ave and variance σ from the difference luminance distribution ΔS, and obtaining an output value A from the following equation (2):

Output value A = dispersion σ / average luminance distribution ΔS ave equation (2)

(H) Steps (A) to (G) are performed on a reference anti-glare transparent substrate to obtain a reference output value Q instead of the output value A. ) Is performed before the steps (A) to (G) or in parallel with the steps (A) to (G).
(I) A step of obtaining a glare index value G from the following equation (3):

Glitter index value G = (output value A) / (reference output value Q) Equation (3)

Is provided.
　本発明による透明基体の光学特性を評価する方法では、以下に詳しく示すように、アンチグレア処理の方法によらず、アンチグレア処理された透明基体の防眩性およびぎらつきの両方を、適正に評価することが可能になる。 In the method for evaluating the optical properties of the transparent substrate according to the present invention, as will be described in detail below, both the antiglare property and the glare of the transparent substrate treated with antiglare are properly evaluated regardless of the method of antiglare treatment. Is possible.
　また、本発明による方法では、透明基体の防眩性およびぎらつきとして、数値化された値が使用される。このため、防眩性およびぎらつきに関して、観察者の主観や先入観にとらわれず、これらの光学特性を、客観的かつ定量的に判断可能である。 Also, in the method according to the present invention, numerical values are used as the antiglare property and glare of the transparent substrate. For this reason, regarding the antiglare property and the glare, these optical characteristics can be objectively and quantitatively determined without being constrained by the subjectivity or preconception of the observer.
　（本発明による透明基体の光学特性を評価する方法の一実施形態について）
　次に図面を参照して、本発明による方法に使用され得る、透明基体の防眩性およびぎらつきのそれぞれを評価する方法の一実施形態について説明する。 (One embodiment of a method for evaluating optical properties of a transparent substrate according to the present invention)
Next, an embodiment of a method for evaluating each of the antiglare property and glare of a transparent substrate, which can be used in the method according to the present invention, will be described with reference to the drawings.
　（防眩性評価方法）
　図１には、本発明の一実施形態による透明基体の防眩性を評価する方法のフローを概略的に示す。 (Anti-glare evaluation method)
FIG. 1 schematically shows a flow of a method for evaluating the antiglare property of a transparent substrate according to an embodiment of the present invention.
　図１に示すように、この透明基体の防眩性を評価する方法（以下、「第１の方法」とも称する）は、
　（ａ）第１および第２の表面を有する透明基体の前記第１の表面側から、前記透明基体の厚さ方向に対して２０゜の方向に第１の光を照射し、前記第１の表面で正反射する光（以下、「２０゜正反射光」ともいう）の輝度を測定するステップ（ステップＳ１１０）と、
　（ｂ）前記第１の表面により反射される反射光の受光角度を－２０°～＋６０°の範囲で変化させ、前記第１の表面により反射される第１の光（以下、「全反射光」ともいう）の輝度を測定するステップ（ステップＳ１２０）と、
　（ｃ）以下の式（１）から、防眩性指標値Ｒを算定するステップ（ステップＳ１３０）
 
　防眩性指標値Ｒ＝
　　　　（全反射光の輝度－２０゜正反射光の輝度）／（全反射光の輝度）　　式（１）
 
　と、を有する。 As shown in FIG. 1, the method for evaluating the antiglare property of the transparent substrate (hereinafter also referred to as “first method”) is:
(A) The first light is irradiated from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 ° with respect to the thickness direction of the transparent substrate; Measuring the brightness of light regularly reflected on the surface (hereinafter also referred to as “20 ° specularly reflected light”) (step S110);
(B) The light receiving angle of the reflected light reflected by the first surface is changed in a range of −20 ° to + 60 °, and the first light reflected by the first surface (hereinafter referred to as “total reflected light”). A step (step S120) of measuring the luminance of
(C) Step of calculating an antiglare index value R from the following equation (1) (step S130)

Anti-glare index value R =
(Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1)

And having.
　以下、各ステップについて説明する。 Hereafter, each step will be described.
　（ステップＳ１１０）
　まず、相互に対向する第１および第２の表面を有する透明基体が準備される。 (Step S110)
First, a transparent substrate having first and second surfaces facing each other is prepared.
　透明基体は、透明である限り、いかなる材料で構成されても良い。透明基体は、例えば、ガラスまたはプラスチック等であっても良い。 The transparent substrate may be made of any material as long as it is transparent. The transparent substrate may be, for example, glass or plastic.
　透明基体がガラスで構成される場合、ガラスの組成は特に限られない。ガラスは、例えば、ソーダライムガラスまたはアルミノシリケートガラスであっても良い。 When the transparent substrate is made of glass, the composition of the glass is not particularly limited. The glass may be, for example, soda lime glass or aluminosilicate glass.
　また、透明基体がガラスで構成される場合、第１および／または第２の表面は、化学強化処理されても良い。 Further, when the transparent substrate is made of glass, the first and / or second surfaces may be chemically strengthened.
　ここで、化学強化処理とは、アルカリ金属を含む溶融塩中にガラス基板を浸漬させ、ガラス基板の最表面に存在するイオン半径の小さなアルカリ金属（イオン）を、溶融塩中に存在するイオン半径の大きなアルカリ金属（イオン）と置換する技術の総称を言う。化学強化処理法では、処理されたガラス基板の表面には、元の原子よりもイオン半径の大きなアルカリ金属（イオン）が配置される。このため、ガラス基板の表面に圧縮応力を付与することができ、これによりガラス基板の強度（特にワレ強度）が向上する。 Here, the chemical strengthening treatment means that a glass substrate is immersed in a molten salt containing an alkali metal, and an alkali metal (ion) having a small ionic radius existing on the outermost surface of the glass substrate is converted into an ionic radius existing in the molten salt. This is a generic term for technologies that substitute for large alkali metals (ions). In the chemical strengthening treatment method, an alkali metal (ion) having an ionic radius larger than that of the original atom is arranged on the surface of the treated glass substrate. For this reason, compressive stress can be given to the surface of a glass substrate, and the intensity | strength (especially crack strength) of a glass substrate improves by this.
　例えば、ガラス基板がナトリウムイオン（Ｎａ＋）を含む場合、化学強化処理により、このナトリウムイオンは、例えばカリウムイオン（Ｋ＋）と置換される。または、例えば、ガラス基板がリチウムイオン（Ｌｉ＋）を含む場合、化学強化処理により、このリチウムイオンは、例えばナトリウムイオン（Ｎａ＋）および／またはカリウムイオン（Ｋ＋）と置換されても良い。 For example, when the glass substrate contains sodium ions (Na + ), the sodium ions are replaced with, for example, potassium ions (K + ) by the chemical strengthening treatment. Alternatively, for example, when the glass substrate includes lithium ions (Li + ), the lithium ions may be replaced with, for example, sodium ions (Na + ) and / or potassium ions (K + ) by chemical strengthening treatment.
　一方、透明基体がプラスチックで構成される場合、プラスチックの組成は特に限られない。透明基体は、例えばポリカーボネート基板であっても良い。 On the other hand, when the transparent substrate is made of plastic, the composition of the plastic is not particularly limited. The transparent substrate may be a polycarbonate substrate, for example.
　なお、ステップＳ１１０の前に、透明基体の第１の表面を、アンチグレア処理するステップが実施される。アンチグレア処理の方法は、特に限られない。アンチグレア処理は、例えば、フロスト処理、エッチング処理、サンドブラスト処理、ラッピング処理、またはシリカコート処理等であっても良い。 Note that, before step S110, an anti-glare process is performed on the first surface of the transparent substrate. The method of anti-glare processing is not particularly limited. The anti-glare process may be, for example, a frost process, an etching process, a sand blast process, a lapping process, or a silica coat process.
　本発明の一実施形態による防眩性測定方法では、透明基体の防眩性を示す定量的な指標値（防眩性指標値Ｒ）を用いて、各種透明基体を一律に評価できる。従って、アンチグレア処理の方法として、各種方法を採用することができる。 In the anti-glare measuring method according to one embodiment of the present invention, various transparent substrates can be uniformly evaluated using a quantitative index value (anti-glare index value R) indicating the anti-glare property of the transparent substrate. Accordingly, various methods can be employed as the antiglare processing method.
　アンチグレア処理後の透明基体の第１の表面は、例えば、０．０５μｍ～１．０μｍの範囲の表面粗さ（算術平均粗さＲａ）を有しても良い。 The first surface of the transparent substrate after the antiglare treatment may have a surface roughness (arithmetic average roughness Ra) in the range of 0.05 μm to 1.0 μm, for example.
　次に、準備された透明基体の第１の表面側から、透明基体の厚さ方向に対して２０゜±０．５゜の方向に向かって、第１の光が照射される。第１の光は、透明基体の第１の表面で反射される。この反射光のうち、２０゜正反射光を受光し、その輝度を測定して、「２０゜正反射光の輝度」とする。 Next, the first light is irradiated from the first surface side of the prepared transparent substrate toward the direction of 20 ° ± 0.5 ° with respect to the thickness direction of the transparent substrate. The first light is reflected from the first surface of the transparent substrate. Of the reflected light, 20 ° specularly reflected light is received and the luminance is measured to obtain “the luminance of the 20 ° regular reflected light”.
　（ステップＳ１２０）
　次に、第１の表面で反射される反射光の受光角度を－２０°～＋６０°の範囲で変化させ、同様の操作を実施する。この際に、透明基体の第１の表面で反射して、第１の表面から出射される第１の光の輝度分布を測定して合計し、「全反射光の輝度」とする。 (Step S120)
Next, the light receiving angle of the reflected light reflected from the first surface is changed in the range of −20 ° to + 60 °, and the same operation is performed. At this time, the luminance distribution of the first light reflected from the first surface of the transparent substrate and emitted from the first surface is measured and summed to obtain “the luminance of the total reflected light”.
　（ステップＳ１３０）
　次に、以下の式（１）から、防眩性指標値Ｒを算定する：
 
　防眩性指標値Ｒ＝
　　　　（全反射光の輝度－２０゜正反射光の輝度）／（全反射光の輝度）　　式（１）
 
　この防眩性指標値Ｒは、後述するように、観察者の目視による防眩性の判断結果と相関し、人の視感に近い挙動を示すことが確認されている。例えば、防眩性指標値Ｒが大きな値（１に近い値）を示す透明基体は、防眩性に優れ、逆に防眩性指標値Ｒが小さな値を示す透明基体は、防眩性が劣る傾向にある。従って、この防眩性指標値Ｒは、透明基体の防眩性を判断する際の定量的指標として、使用可能である。 (Step S130)
Next, the antiglare index value R is calculated from the following formula (1):

Anti-glare index value R =
(Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1)

As will be described later, it has been confirmed that the antiglare index value R correlates with the result of determination of antiglare by visual observation by an observer and exhibits a behavior close to human visual perception. For example, a transparent substrate having a large antiglare index value R (a value close to 1) has excellent antiglare properties, and conversely, a transparent substrate having a small antiglare index value R has antiglare properties. It tends to be inferior. Therefore, the anti-glare index value R can be used as a quantitative index when judging the anti-glare property of the transparent substrate.
　図２には、前述の式（１）で表される防眩性指標値Ｒを取得する際に使用される、測定装置の一例を模式的に示す。 FIG. 2 schematically shows an example of a measuring apparatus used when obtaining the antiglare index value R represented by the above-described formula (1).
　図２に示すように、測定装置３００は、光源３５０および検出器３７０を有し、測定装置３００内に、透明基体２１０が配置される。透明基体２１０は、第１の表面２１２および第２の表面２１４を有する。光源３５０は、透明基体２１０に向かって、第１の光３６２を放射する。検出器３７０は、第１の表面２１２において反射される反射光３６４を受光し、その輝度を検出する。 As shown in FIG. 2, the measuring apparatus 300 includes a light source 350 and a detector 370, and the transparent substrate 210 is disposed in the measuring apparatus 300. The transparent substrate 210 has a first surface 212 and a second surface 214. The light source 350 emits first light 362 toward the transparent substrate 210. The detector 370 receives the reflected light 364 reflected on the first surface 212 and detects its brightness.
　なお、透明基体２１０は、第１の表面２１２が光源３５０および検出器３７０の側となるように配置される。従って、検出器３７０が検出する第１の光は、透明基体２１０で反射された反射光３６４である。また、透明基体２１０の一方の表面がアンチグレア処理されている場合、このアンチグレア処理されている表面が、透明基体２１０の第１の表面２１２となる。すなわち、この場合、透明基体２１０は、アンチグレア処理されている表面が光源３５０および検出器３７０の側となるようにして、測定装置３００内に配置される。 The transparent substrate 210 is disposed so that the first surface 212 is on the light source 350 and the detector 370 side. Accordingly, the first light detected by the detector 370 is reflected light 364 reflected by the transparent substrate 210. In addition, when one surface of the transparent substrate 210 is subjected to antiglare treatment, the surface subjected to the antiglare treatment becomes the first surface 212 of the transparent substrate 210. That is, in this case, the transparent substrate 210 is disposed in the measurement apparatus 300 such that the antiglare-treated surface is on the light source 350 and the detector 370 side.
　また、第１の光３６２は、透明基体２１０の厚さ方向に対して、２０゜傾斜した角度で照射される。なお、本願では、測定装置の誤差を考慮して、２０゜±０．５゜の範囲を、角度２０゜と定義する。 Further, the first light 362 is irradiated at an angle inclined by 20 ° with respect to the thickness direction of the transparent substrate 210. In the present application, a range of 20 ° ± 0.5 ° is defined as an angle of 20 ° in consideration of an error of the measuring apparatus.
　このような測定装置３００において、光源３５０から透明基体２１０に向かって第１の光３６２を照射し、受光角度φが２０゜となるように配置された検出器３７０を用いて、透明基体２１０の第１の表面２１２で反射される正反射光３６４を検出する。これにより、「２０゜正反射光」が検出される。 In such a measuring apparatus 300, the first light 362 is irradiated from the light source 350 toward the transparent substrate 210, and the detector 370 disposed so that the light receiving angle φ is 20 ° is used. Specular light 364 reflected by the first surface 212 is detected. Thereby, “20 ° specularly reflected light” is detected.
　次に、検出器３７０において、反射光３６４を測定する受光角度φを、－２０゜～＋６０゜の範囲で変化させ、同様の操作を実施する。 Next, in the detector 370, the light receiving angle φ for measuring the reflected light 364 is changed in the range of −20 ° to + 60 °, and the same operation is performed.
　そして、受光角度φ＝－２０゜～＋６０゜の範囲で、透明基体２１０の第１の表面２１２で反射された反射光３６４（全反射光という）の輝度分布を検出し、合計する。 Then, the brightness distribution of the reflected light 364 (referred to as total reflected light) reflected by the first surface 212 of the transparent substrate 210 is detected within the range of the light receiving angle φ = −20 ° to + 60 ° and summed.
　ここで、受光角度φのマイナス（－）は、当該受光角度が、評価対象となる対象表面（上記例では第１の表面）の法線よりも、入射光側にあることを表し、プラス（＋）は、当該受光角度が、対象表面の法線に比べて、入射光側にないことを表す。 Here, minus (−) of the light receiving angle φ represents that the light receiving angle is on the incident light side with respect to the normal line of the target surface to be evaluated (first surface in the above example), and plus ( (+) Indicates that the light receiving angle is not on the incident light side compared to the normal of the target surface.
　得られた２０゜正反射光の輝度および全反射光の輝度から、前述の式（１）により、透明基体２１０の防眩性指標値Ｒを取得できる。なお、このような測定は、市販のゴニオメータ（変角光度計）を使用することにより、容易に実施できる。 The antiglare index value R of the transparent substrate 210 can be obtained from the brightness of the obtained 20 ° specularly reflected light and the brightness of the totally reflected light by the above-described formula (1). Such a measurement can be easily performed by using a commercially available goniometer (variable photometer).
　なお、第１の光の照射角度は６０°～５°の範囲から適宜選択できる。ただし、本願では、目視観察による防眩性評価と定量評価とが良好な相関を示す観点から、第１の光の照射角度として、２０°を選択している。 Note that the irradiation angle of the first light can be appropriately selected from the range of 60 ° to 5 °. However, in the present application, 20 ° is selected as the irradiation angle of the first light from the viewpoint that the anti-glare evaluation and the quantitative evaluation by visual observation show a good correlation.
　（ぎらつき指標値について）
　図３には、本発明の一実施形態による透明基体のぎらつきを評価する方法のフローを概略的に示す。 (About glaring index values)
FIG. 3 schematically shows a flow of a method for evaluating glare of a transparent substrate according to an embodiment of the present invention.
　図３に示すように、この透明基体のぎらつきを評価する方法（以下、「第２の方法」とも称する）は、
　（Ａ）第１および第２の表面を有する透明基体を、第２の表面が表示装置の側になるようにして、前記表示装置の上に配置するステップ（ステップＳ２１０）と、
　（Ｂ）前記表示装置をオンにした状態で、固体撮像素子を用いて前記透明基体を撮影し、第１の画像を取得するステップであって、前記固体撮像素子と前記透明基体の間の距離をｄとし、前記固体撮像素子の焦点距離をｆとしたとき、撮影の際の距離指数ｒ（＝ｄ／ｆ）は、８以上であるステップ（ステップＳ２２０）と、
　（Ｃ）前記取得された第１の画像から、第１の輝度分布を形成するステップ（ステップＳ２３０）と、
　（Ｄ）前記透明基体を、前記第２の表面と略平行な方向に動かし、前記透明基体を前記表示装置に対して移動させるステップ（ステップＳ２４０）と、
　（Ｅ）前記（Ｂ）および（Ｃ）のステップを繰り返し、取得された第２の画像から、第２の輝度分布を形成するステップ（ステップＳ２５０）と、
　（Ｆ）前記第１の輝度分布と前記第２の輝度分布の差分から、差分輝度分布ΔＳを求めるステップ（ステップＳ２６０）と、
　（Ｇ）前記差分輝度分布ΔＳから、平均輝度分布ΔＳａｖｅおよび分散σを算定するとともに、以下の式（２）から、出力値Ａを得るステップ（ステップＳ２７０）と、
 
　　出力値Ａ＝分散σ／平均輝度分布ΔＳａｖｅ　　式（２）
 
　（Ｈ）前記（Ａ）～（Ｇ）のステップを、基準用のアンチグレア処理された透明基体で実施して、出力値Ａの代わりに、参照出力値Ｑを得るステップ（ステップＳ２８０）と、
　（Ｉ）以下の式（３）から、ぎらつき指標値Ｇを求めるステップ（ステップＳ２９０）と、
 
　　ぎらつき指標値Ｇ＝（出力値Ａ）／（参照出力値Ｑ）　　　式（３）
 
　を有する。 As shown in FIG. 3, a method for evaluating the glare of the transparent substrate (hereinafter, also referred to as “second method”)
(A) disposing a transparent substrate having first and second surfaces on the display device such that the second surface is on the display device side (step S210);
(B) A step of photographing the transparent substrate using a solid-state imaging device and obtaining a first image with the display device turned on, and a distance between the solid-state imaging device and the transparent substrate. Where d is the focal length of the solid-state image sensor and f is the distance index r (= d / f) when shooting is 8 or more (step S220),
(C) forming a first luminance distribution from the acquired first image (step S230);
(D) moving the transparent substrate in a direction substantially parallel to the second surface to move the transparent substrate relative to the display device (step S240);
(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image (step S250);
(F) obtaining a difference luminance distribution ΔS from the difference between the first luminance distribution and the second luminance distribution (step S260);
(G) calculating an average luminance distribution ΔS ave and variance σ from the difference luminance distribution ΔS and obtaining an output value A from the following equation (2) (step S270);

Output value A = dispersion σ / average luminance distribution ΔS ave equation (2)

(H) Steps (A) to (G) are performed on a reference anti-glare transparent substrate to obtain a reference output value Q instead of the output value A (step S280);
(I) A step of obtaining a glare index value G from the following equation (3) (step S290);

Glitter index value G = (output value A) / (reference output value Q) Equation (3)

Have
　以下、各ステップについて詳しく説明する。 Hereinafter, each step will be described in detail.
　（ステップＳ２１０）
　まず、相互に対向する第１および第２の表面を有する透明基体が準備される。透明基体は、第１の表面がアンチグレア処理されている。 (Step S210)
First, a transparent substrate having first and second surfaces facing each other is prepared. The transparent substrate is antiglare treated on the first surface.
　なお、透明基体の材質、組成等は、前述のステップＳ１１０において示したものと同様であるため、ここではこれ以上説明しない。 The material, composition, etc. of the transparent substrate are the same as those shown in step S110 described above, and will not be described further here.
　ただし、前述のように、従来、例えばエッチング処理内での条件変更のような、単一のアンチグレア処理方法間のみならず、複数存在するアンチグレア処理方法によって異なる様々な表面を有する透明基体のぎらつきを、同じ指標で一律に評価することは難しかった。 However, as described above, the glare of a transparent substrate having various surfaces that differ according to a plurality of anti-glare treatment methods as well as between conventional single anti-glare treatment methods, such as a change in conditions in an etching process. It was difficult to uniformly evaluate with the same index.
　しかしながら、本発明の一実施形態によるぎらつき評価方法では、以降に示すように、透明基体のぎらつきを示す定量的な指標値（ぎらつき指標値Ｇ）を用いて、各種透明基体を一律に評価可能である。従って、本発明の一実施形態によるぎらつき評価方法は、アンチグレア処理の処理方法を選択する手段としても有用であることに留意する必要がある。 However, in the glare evaluation method according to an embodiment of the present invention, as described below, various transparent substrates are uniformly used by using a quantitative index value (glaring index value G) indicating the glare of the transparent substrate. It can be evaluated. Therefore, it should be noted that the glare evaluation method according to an embodiment of the present invention is also useful as a means for selecting a processing method for anti-glare processing.
　次に、表示装置が準備される。表示装置は、画素（ピクセル）を有するものである限り、特に限られない。表示装置は、例えば、ＬＣＤ装置、ＯＬＥＤ（Ｏｒｇａｎｉｃ　Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）装置、ＰＤＰ（Ｐｌａｓｍａ　Ｄｉｓｐｌａｙ　Ｐａｎｅｌ）装置、またはタブレット型表示装置等であっても良い。表示装置の解像度は、例えば１３２ｐｐｉ以上が好ましく、１８６ｐｐｉ以上がより好ましく、２６４ｐｐｉ以上がさらに好ましい。 Next, a display device is prepared. The display device is not particularly limited as long as it has a picture element (pixel). The display device may be, for example, an LCD device, an OLED (Organic Light Emitting Diode) device, a PDP (Plasma Display Panel) device, or a tablet display device. The resolution of the display device is, for example, preferably 132 ppi or more, more preferably 186 ppi or more, and further preferably 264 ppi or more.
　次に、表示装置の上に透明基体が配置される。この際には、透明基体は、第２の表面が表示装置の側になるようにして、表示装置の上に配置される。 Next, a transparent substrate is disposed on the display device. In this case, the transparent substrate is disposed on the display device such that the second surface is on the display device side.
　（ステップＳ２２０）
　次に、表示装置をＯＮにした状態（すなわち画像を表示させた状態）で、固体撮像素子を用いて、透明基体を第１の表面側から撮影し、表示装置上に配置された透明基体の画像（第１の画像）を取得する。 (Step S220)
Next, in a state where the display device is turned on (that is, a state where an image is displayed), the transparent substrate is photographed from the first surface side using the solid-state imaging device, and the transparent substrate disposed on the display device is An image (first image) is acquired.
　固体撮像素子と透明基体の間の距離ｄは、所定の値に設定される。 The distance d between the solid-state imaging device and the transparent substrate is set to a predetermined value.
　なお、本願では、固体撮像素子と透明基体の間の距離ｄに対応する指標として、距離指数ｒを使用する。ここで、距離指数ｒは、固体撮像素子の焦点距離ｆおよび固体撮像素子と透明基体の間の距離ｄを用いて、以下の式（４）で表される：
 
　　距離指数ｒ＝（固体撮像素子と透明基体の間の距離ｄ）／
（固体撮像素子の焦点距離ｆ）　　　式（４）
 
　なお、本願では、距離指数ｒは、８以上である。 In the present application, a distance index r is used as an index corresponding to the distance d between the solid-state imaging device and the transparent substrate. Here, the distance index r is expressed by the following formula (4) using the focal length f of the solid-state imaging device and the distance d between the solid-state imaging device and the transparent substrate:

Distance index r = (distance d between solid-state imaging device and transparent substrate) /
(Focal distance f of solid-state image sensor) Formula (4)

In the present application, the distance index r is 8 or more.
　これは、距離指数ｒが８よりも小さくなると、固体撮像素子と透明基体の間の距離ｄが小さくなり、透明基体のアンチグレア処理された第１の表面の形態の影響を受けやすくなるためである。従って、距離指数ｒを８以上とすることにより、適用されたアンチグレア処理の方法の相違による第１の表面の形態の差異の影響を有意に抑制した状態で、各種方法でアンチグレア処理された透明基体のぎらつきを、一律に評価することが可能となる。 This is because when the distance index r is smaller than 8, the distance d between the solid-state imaging device and the transparent substrate becomes small, and is easily affected by the form of the first surface of the transparent substrate subjected to the antiglare treatment. . Therefore, by setting the distance index r to 8 or more, the transparent substrate that has been anti-glare treated by various methods in a state where the influence of the difference in the shape of the first surface due to the difference in the applied anti-glare treatment method is significantly suppressed. It is possible to uniformly evaluate glare.
　距離指数ｒは、９以上であることが好ましく、１０以上であることがより好ましい。 The distance index r is preferably 9 or more, and more preferably 10 or more.
　表示装置に表示させる像は、単一色（例えば緑色）の像であって、表示装置の表示画面全体に表示されることが好ましい。表示色の違いによる見え方の違い等の影響を極力小さくするためである。 The image displayed on the display device is a single color (for example, green) image, and is preferably displayed on the entire display screen of the display device. This is for minimizing the influence of differences in appearance due to differences in display colors.
　固体撮像素子としては、例えば、電荷結合素子（ＣＣＤ）や相補性金属酸化膜半導体（ＣＭＯＳ）が利用できる。いずれを採用する場合にも、高画素数を有するデジタルカメラ等を使用することが好ましい。 As the solid-state imaging device, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used. In any case, it is preferable to use a digital camera or the like having a high number of pixels.
　このステップにより、例えば図４に模式的に示すような第１の画像４１０が得られる。図４に示す例では、第１の画像４１０において、表示装置の一部の３行×３列に配列された９個のピクセルに対応した領域（以下、対応領域４２０－１～４２０－９という）が明るく視認されている。 By this step, for example, a first image 410 as schematically shown in FIG. 4 is obtained. In the example shown in FIG. 4, in the first image 410, a region corresponding to nine pixels arranged in 3 rows × 3 columns of a part of the display device (hereinafter referred to as corresponding regions 420-1 to 420-9). ) Is brightly visible.
　なお、図４では、明確化のため、各対応領域４２０－１～４２０－９同士が十分に離間された状態で示されている。しかしながら、実際の画像では、各対応領域４２０－１～４２０－９間の距離はより狭く、隣接する対応領域同士で、明るい部分が一部重なり合う場合もあることに留意する必要がある。 In FIG. 4, for the sake of clarity, the corresponding areas 420-1 to 420-9 are shown in a sufficiently separated state. However, it should be noted that in the actual image, the distance between the corresponding areas 420-1 to 420-9 is narrower, and the bright portions may partially overlap between the adjacent corresponding areas.
　（ステップＳ２３０）
　次に、ステップＳ２２０において撮影された第１の画像４１０が画像解析され、第１の輝度分布が形成される。第１の輝度分布は、ＸＹ平面上に、立体的なマップとして形成される。 (Step S230)
Next, the first image 410 captured in step S220 is subjected to image analysis, and a first luminance distribution is formed. The first luminance distribution is formed as a three-dimensional map on the XY plane.
　図５には、このステップで得られる第１の輝度分布の一例を模式的に示す。 FIG. 5 schematically shows an example of the first luminance distribution obtained in this step.
　図５に示すように、第１の輝度分布４３０は、第１の画像４１０の各対応領域４２０－１～４２０－９に対応する領域のそれぞれに、略正規分布形状の輝度分布成分ｑ１～ｑ９を有する。より一般的には第１の輝度分布４３０は、ｉ個の複数の輝度分布成分ｑｉの集まりで表される（ｉは２以上の整数）。 As shown in FIG. 5, the first luminance distribution 430 includes luminance distribution components q 1 to q having a substantially normal distribution shape in the areas corresponding to the corresponding areas 420-1 to 420-9 of the first image 410, respectively. with a q 9. More generally, the first luminance distribution 430 is represented by a set of i plural luminance distribution components q i (i is an integer of 2 or more).
　図５では、描写が複雑になることを避けるため、輝度分布成分ｑ１～ｑ９は、２次元的に（すなわち非立体的に）示されていることに留意する必要がある。 In FIG. 5, it should be noted that the luminance distribution components q 1 to q 9 are shown two-dimensionally (that is, non-stereoscopically) in order to avoid complicated description.
　なお、第１の輝度分布４３０の精度を高めるため、ステップＳ２２０において撮影される第１の画像４１０の枚数を増やし、このステップＳ２３０では、それぞれの第１の画像４１０に対して、同様の画像解析を実施しても良い。この場合、その後、各画像解析結果を平均化することにより、より精度の高い第１の輝度分布４３０が得られる。 In order to increase the accuracy of the first luminance distribution 430, the number of the first images 410 to be photographed is increased in step S220, and in this step S230, the same image analysis is performed for each first image 410. May be implemented. In this case, the first luminance distribution 430 with higher accuracy can be obtained by averaging the image analysis results thereafter.
　（ステップＳ２４０）
　次に、透明基体を、第２の表面と平行な方向にスライドさせ、透明基体を表示装置に対して相対移動させる。移動距離は、１０ｍｍ未満であることが好ましく、例えば、数ｍｍであっても良い。 (Step S240)
Next, the transparent substrate is slid in a direction parallel to the second surface, and the transparent substrate is moved relative to the display device. The moving distance is preferably less than 10 mm, and may be several mm, for example.
　（ステップＳ２５０）
　次に、前記ステップＳ２２０～ステップＳ２３０を繰り返す。すなわち、表示装置をＯＮにした状態で、固体撮像素子により第２の画像を取得するとともに、第２の画像から、第２の輝度分布を形成する。 (Step S250)
Next, steps S220 to S230 are repeated. That is, while the display device is turned on, the second image is acquired by the solid-state imaging device, and the second luminance distribution is formed from the second image.
　このステップにおいても、第２の輝度分布の精度を高めるため、固体撮像素子で撮影される第２の画像の枚数を増やしても良い。その後、それぞれの第２の画像に対して画像解析を実施して、各画像解析結果を平均化することにより、より精度の高い第２の輝度分布が得られる。 Also in this step, the number of second images taken by the solid-state imaging device may be increased in order to increase the accuracy of the second luminance distribution. Thereafter, image analysis is performed on each second image, and each image analysis result is averaged to obtain a second luminance distribution with higher accuracy.
　これにより、複数の輝度分布成分ｓｉ（ここでｉは２以上の整数）の集まりで表わされる第２の輝度分布が得られる。なお、輝度分布成分ｓｉは、輝度分布成分ｑｉと同じ数で構成される。 As a result, a second luminance distribution represented by a collection of a plurality of luminance distribution components s i (where i is an integer of 2 or more) is obtained. Note that the luminance distribution components si are configured with the same number as the luminance distribution components qi.
　（ステップＳ２６０）
　次に、第１の輝度分布と第２の輝度分布の差分から、差分輝度分布ΔＳが算定される。差分輝度分布ΔＳは、第１の輝度分布および第２の輝度分布と同様に、略正規分布形状の輝度分布成分ｔｉ（ここでｉは２以上の整数）の集まりで表わされる。 (Step S260)
Next, the difference luminance distribution ΔS is calculated from the difference between the first luminance distribution and the second luminance distribution. Similar to the first luminance distribution and the second luminance distribution, the difference luminance distribution ΔS is represented by a collection of luminance distribution components t i (where i is an integer of 2 or more) having a substantially normal distribution shape.
　（ステップＳ２７０）
　次に、ステップＳ２６０で得られた差分輝度分布ΔＳを用いて、平均輝度分布ΔＳａｖｅおよび分散σが算定される。 (Step S270)
Next, the average luminance distribution ΔS ave and the variance σ are calculated using the difference luminance distribution ΔS obtained in step S260.
　ここで、平均輝度分布ΔＳａｖｅは、差分輝度分布ΔＳに含まれるｉ個の輝度分布成分ｔｉの絶対値を平均化することにより、求めることができる。また、分散σは、差分輝度分布ΔＳに含まれるｉ個の輝度分布成分ｔｉと、平均輝度分布ΔＳａｖｅを用いて、以下の式（５）から求めることができる。 Here, the average luminance distribution ΔS ave can be obtained by averaging the absolute values of i luminance distribution components t i included in the difference luminance distribution ΔS. The variance σ can be obtained from the following equation (5) using i luminance distribution components t i included in the difference luminance distribution ΔS and the average luminance distribution ΔS ave .
Figure JPOXMLDOC01-appb-M000001
  
　得られた平均輝度分布ΔＳａｖｅおよび分散σから、以下の式（２）により、出力値Ａが算定される
 
　　出力値Ａ＝分散σ／平均輝度分布ΔＳａｖｅ　　式（２）
 
　（ステップＳ２８０）
　次に、基準（リファレンス）用のアンチグレア処理された透明基体を用いて、前述のステップＳ２１０～ステップＳ２７０までのステップを実施する。これにより、前記式（２）の出力値Ａの代わりに、参照出力値Ｑが取得される。
Figure JPOXMLDOC01-appb-M000001
From the obtained average luminance distribution ΔS ave and variance σ, the output value A is calculated by the following equation (2).
Output value A = dispersion σ / average luminance distribution ΔS ave equation (2)

(Step S280)
Next, the above-described steps S210 to S270 are carried out using a reference (reference) anti-glare-treated transparent substrate. As a result, the reference output value Q is obtained instead of the output value A in the equation (2).
　ぎらつき指標値は後述の（３）式のとおり得られた参照出力値Ｑとの比率で表されるため、参照出力値Ｑは測定再現性が強く求められ、測定毎の誤差より十分に大きいことが必要とされる。適切な参照出力値Ｑを与える基準（リファレンス）用のアンチグレア処理された透明基体を簡便に用意するには、ソーダライムガラスをフロスト・エッチングによるアンチグレア処理をした平板状のガラスで、６０度グロス値がなるべく大きく、かつ粗さ曲線要素の平均長さＲＳｍが７０μｍ以上１２０μｍ未満のものであって、市販品として入手可能なものを選定すればよい。 Since the glare index value is represented by the ratio with the reference output value Q obtained as shown in the later-described equation (3), the reference output value Q is strongly required to be reproducible in measurement and is sufficiently larger than the error for each measurement. Is needed. In order to easily prepare an anti-glare-treated transparent substrate for a reference (reference) that gives an appropriate reference output value Q, soda lime glass is a flat glass that has been anti-glare treated by frost etching, and has a gloss value of 60 degrees. Is as large as possible, and the average length RSm of the roughness curve elements is 70 μm or more and less than 120 μm, and a commercially available product may be selected.
　ここで６０度グロス値はＪＩＳ－Ｚ８７４１に準拠した方法により鏡面光沢度として測定できる。６０度グロス値はたとえば１１０以上であり、１２０以上がより好ましい。粗さ曲線要素の平均長さＲＳｍはＪＩＳ　Ｂ０６０１（２００１）に準拠した方法により測定できる。粗さ曲線要素の平均長さＲＳｍはたとえば７０μｍ以上であり、８０μｍ以上がより好ましく、かつ１２０μｍ未満であり、１１０μｍ未満が好ましい。 Here, the 60 degree gloss value can be measured as the specular gloss by a method based on JIS-Z8741. The 60 degree gloss value is, for example, 110 or more, and more preferably 120 or more. The average length RSm of the roughness curve element can be measured by a method based on JIS B0601 (2001). The average length RSm of the roughness curve element is, for example, 70 μm or more, more preferably 80 μm or more, and less than 120 μm, preferably less than 110 μm.
　本発明の一実施形態においては、上記のような条件を満たす基準用のアンチグレア処理された透明基体として、６０度グロス値が１４０％、かつ表粗さ曲線要素の平均長さＲＳｍが８５μｍである、ＶＲＤ１４０アンチグレア処理ガラス（旭硝子株式会社製）を選定した。 In one embodiment of the present invention, the reference antiglare-treated transparent substrate that satisfies the above conditions has a 60-degree gloss value of 140% and an average length RSm of the surface roughness curve element of 85 μm. VRD140 anti-glare treated glass (manufactured by Asahi Glass Co., Ltd.) was selected.
　なお、このステップＳ２８０は、評価用のアンチグレア処理された透明基体を用いて、前述のステップＳ２１０～ステップＳ２７０を実施する前に実施されても良い。または、このステップＳ２８０は、評価用のアンチグレア処理された透明基体におけるステップＳ２１０～ステップＳ２７０の実施と並列に、実施されても良い。 Note that this step S280 may be performed before performing the above-described steps S210 to S270 using a transparent substrate subjected to an anti-glare process for evaluation. Alternatively, this step S280 may be performed in parallel with the execution of steps S210 to S270 on the anti-glare-treated transparent substrate for evaluation.
　（ステップＳ２９０）
　次に、出力値Ａおよび参照出力値Ｑを用いて、以下の式（３）から、ぎらつき指標値Ｇが求められる：
 
　　ぎらつき指標値Ｇ＝（出力値Ａ）／（参照出力値Ｑ）　　　式（３）
 
　このぎらつき指標値Ｇは、後述するように、観察者の目視によるぎらつきの判断結果と相関し、人の視感に近い挙動を示すことが確認されている。例えば、ぎらつき指標値Ｇが大きな透明基体は、ぎらつきが顕著であり、逆にぎらつき指標値Ｇが小さな透明基体は、ぎらつきが抑制される傾向にある。従って、このぎらつき指標値Ｇは、透明基体のぎらつきを判断する際の定量的指標として使用できる。 (Step S290)
Next, using the output value A and the reference output value Q, the glare index value G is obtained from the following equation (3):

Glitter index value G = (output value A) / (reference output value Q) Equation (3)

As will be described later, it has been confirmed that the glare index value G correlates with the visual judgment result of the glare by the observer and shows a behavior close to human visual perception. For example, a transparent substrate with a large glare index value G has noticeable glare, and conversely, a transparent substrate with a small glare index value G tends to suppress glare. Therefore, the glare index value G can be used as a quantitative index when judging the glare of the transparent substrate.
　以上、図３～図５を参照して、透明基体のぎらつきを評価する方法の一例について説明した。ただし、本発明において、透明基体のぎらつきを評価する方法は、これに限られるものではない。 The example of the method for evaluating the glare of the transparent substrate has been described above with reference to FIGS. However, in the present invention, the method for evaluating the glare of the transparent substrate is not limited to this.
　例えば、前述のフローにおいて、ステップＳ２６０とステップＳ２７０の間に、差分輝度分布ΔＳから、前記表示装置に由来する成分をフィルタ除去するステップ（ステップＳ２６５）を実施しても良い。差分輝度分布ΔＳの代わりに、この操作によって得られる実効差分輝度分布ΔＳｅを使用して、ステップＳ２７０を実施することにより、得られるぎらつき指標値Ｇの精度をよりいっそう向上させることができる。 For example, in the above-described flow, a step (step S265) of removing a component derived from the display device from the difference luminance distribution ΔS may be performed between step S260 and step S270. Instead of the differential luminance distribution [Delta] S, using the effective difference luminance distribution [Delta] S e obtained by this operation, by performing the step S270, it is possible to further improve the accuracy of the glare index value G obtained.
　ただし、このステップＳ２６５は、必要な際に行われれば良く、必ずしも実施する必要はない。 However, this step S265 may be performed when necessary, and is not necessarily performed.
　なお、以上説明した透明基体のぎらつきを評価する方法は、例えば、ＳＭＳ－１０００装置（Ｄｉｓｐｌａｙ－Ｍｅｓｓｔｅｃｈｎｉｋ＆Ｓｙｓｔｅｍｅ社製）を用いることにより、容易に実施できる。 The method for evaluating the glare of the transparent substrate described above can be easily performed by using, for example, an SMS-1000 apparatus (manufactured by Display-Messtechnik & System).
　以上説明したような防眩性指標値Ｒ、およびぎらつき指標値Ｇを使用することにより、アンチグレア処理された透明基体の光学特性を、定量的に評価することが可能となる。 By using the antiglare index value R and the glare index value G as described above, it is possible to quantitatively evaluate the optical characteristics of the anti-glare-treated transparent substrate.
　（２つの指標による評価）
　次に、透明基体の２つの光学特性を同時に評価する方法およびその効果について説明する。 (Evaluation using two indicators)
Next, a method for simultaneously evaluating two optical characteristics of the transparent substrate and its effect will be described.
　図６には、各種方法でアンチグレア処理された透明基体において得られた、防眩性指標値Ｒ（横軸）とぎらつき指標値Ｇ（縦軸）の関係をプロットした図の一例を示す。ここで、本データ取得のためのぎらつき評価における撮影の際の距離指数ｒ＝１０．８である。 FIG. 6 shows an example of a graph plotting the relationship between the antiglare index value R (horizontal axis) and the glare index value G (vertical axis) obtained in a transparent substrate that has been antiglare treated by various methods. Here, the distance index r at the time of shooting in the glare evaluation for acquiring this data is 10.8.
　図６において、横軸の防眩性指標値Ｒが大きいほど、また縦軸のぎらつき指標値が小さいほど、透明基体の防眩性は向上し、透明基体のぎらつきは抑制される。 In FIG. 6, as the antiglare index value R on the horizontal axis is larger and the glare index value on the vertical axis is smaller, the antiglare property of the transparent substrate is improved and the glare of the transparent substrate is suppressed.
　なお、図６には、参考のため、良好な防眩性と良好なぎらつき防止性とを兼ね備えた、理想的な透明基体の領域がｉｄｅａｌと表示された○印で表されている。 In FIG. 6, for reference, an ideal transparent substrate region having both good anti-glare properties and good anti-glare properties is indicated by a symbol “ideal”.
　ここで、単一の光学的特性、例えばぎらつき防止性のみを考慮して、各種透明基体の中から候補透明基体を選定した場合、図６のハッチングで示された領域Ｃに含まれる透明基体が一様に選定されることになる。すなわち、そのような方法では、防眩性の劣る透明基体が、選定候補透明基体に含まれてしまう。同様に、防眩性のみを考慮して、透明基体を選定した場合、図６のハッチングで示された領域Ｄに含まれる透明基体が一様に選定され、ぎらつき防止性の劣る透明基体が選定候補に含まれてしまう。 Here, in the case where a candidate transparent substrate is selected from various transparent substrates in consideration of only a single optical characteristic, for example, anti-glare property, the transparent substrate included in the region C indicated by hatching in FIG. Will be selected uniformly. That is, in such a method, a transparent substrate with poor antiglare properties is included in the selection candidate transparent substrate. Similarly, when a transparent substrate is selected in consideration of only the antiglare property, the transparent substrate included in the region D indicated by hatching in FIG. 6 is uniformly selected, and a transparent substrate with poor glare prevention property is selected. It will be included in the selection candidates.
　これに対して、図６のようなぎらつき指標値Ｇと防眩性Ｒの相関図を使用した場合、一度に両方の光学特性を考慮して、適正な透明基体を選定することが可能となる。すなわち、このような選定方法では、目的および用途などに応じて、透明基体を適正に選定することができ、すなわち、ぎらつき防止性と防眩性性に関して、最も良好な特性が発揮できるように透明基体を選定することが可能となる。 On the other hand, when the correlation diagram between the glare index value G and the anti-glare property R as shown in FIG. 6 is used, it is possible to select an appropriate transparent substrate in consideration of both optical characteristics at once. . That is, in such a selection method, the transparent substrate can be appropriately selected according to the purpose and application, that is, the best characteristics can be exhibited in terms of glare prevention and antiglare properties. A transparent substrate can be selected.
　このように、本発明の一実施例による方法では、２つの光学的特性を一度に、定量的に考慮できるため、使用目的や用途等に応じて、透明基体をより適正に選定することが可能となる。 As described above, in the method according to the embodiment of the present invention, two optical characteristics can be considered quantitatively at a time, so that a transparent substrate can be selected more appropriately according to the purpose of use and application. It becomes.
　また、本発明による方法では、透明基体の防眩性指標値Ｒ、およびぎらつき指標値Ｇとして、数値化された値が使用される。このため、防眩性およびぎらつきに関して、観察者の主観や先入観にとらわれず、これらの光学特性を、客観的かつ定量的に判断可能である。 In the method according to the present invention, numerical values are used as the antiglare index value R and the glare index value G of the transparent substrate. For this reason, regarding the antiglare property and the glare, these optical characteristics can be objectively and quantitatively determined without being constrained by the subjectivity or preconception of the observer.
　（本発明の一実施形態による透明基体）
　次に、図７を参照して、本発明の一実施形態による透明基体について説明する。 (Transparent substrate according to an embodiment of the present invention)
Next, a transparent substrate according to an embodiment of the present invention will be described with reference to FIG.
　図７には、本発明の一実施形態による透明基体（以下、単に「透明基体」と称する）９００を模式的に示す。 FIG. 7 schematically shows a transparent substrate (hereinafter simply referred to as “transparent substrate”) 900 according to an embodiment of the present invention.
　透明基体９００は、ガラスで構成される。ガラスの組成は、特に限られず、ガラスは、例えば、ソーダライムガラスまたはアルミノシリケートガラスであっても良い。 The transparent substrate 900 is made of glass. The composition of the glass is not particularly limited, and the glass may be, for example, soda lime glass or aluminosilicate glass.
　透明基体９００は、第１の表面９０２および第２の表面９０４を有し、第１の表面９０２は、アンチグレア処理されている。 The transparent substrate 900 has a first surface 902 and a second surface 904, and the first surface 902 is antiglare-treated.
　アンチグレア処理の方法は、特に限られない。アンチグレア処理は、例えば、フロスト処理、エッチング処理、サンドブラスト処理、ラッピング処理、またはシリカコート処理等であっても良い。透明基体の第１の表面９０２は、例えば、０．０５μｍ～１．０μｍの範囲の表面粗さ（算術平均粗さＲａ）を有しても良い。 ア ン チ Anti-glare treatment method is not particularly limited. The anti-glare process may be, for example, a frost process, an etching process, a sand blast process, a lapping process, or a silica coat process. The first surface 902 of the transparent substrate may have a surface roughness (arithmetic average roughness Ra) in the range of 0.05 μm to 1.0 μm, for example.
　また、透明基体９００は、第１の表面９０２および／または第２の表面９０４が、化学強化処理されていても良い。 Further, in the transparent substrate 900, the first surface 902 and / or the second surface 904 may be chemically strengthened.
　透明基体９００の寸法および形状は、特に限られない。例えば、透明基体９００は、正方形状、矩形状、円形状、または楕円形状等であっても良い。 The dimensions and shape of the transparent substrate 900 are not particularly limited. For example, the transparent substrate 900 may have a square shape, a rectangular shape, a circular shape, an elliptical shape, or the like.
　なお、透明基体９００を表示装置の保護カバーとして使用する場合、透明基体９００の厚さは、薄いことが好ましい。例えば、透明基体９００の厚さは、０．２ｍｍ～２．０ｍｍの範囲であっても良い。 When the transparent substrate 900 is used as a protective cover for a display device, the transparent substrate 900 is preferably thin. For example, the thickness of the transparent substrate 900 may be in the range of 0.2 mm to 2.0 mm.
　ここで、透明基体９００は、前述の第１の方法（ステップＳ１１０～ステップＳ１３０）を用いて測定される防眩性指標値Ｒが０．４以上であるという特徴を有する。また、この透明基体９００は、前述の第２の方法（ステップＳ２１０～ステップＳ２９０。ステップＳ２６５を含む）を用いて、距離指数ｒ＝８として測定されるぎらつき指標値Ｇが、０．６以下であるという特徴を有する。 Here, the transparent substrate 900 has a feature that the antiglare index value R measured by using the first method (step S110 to step S130) is 0.4 or more. The transparent substrate 900 has a glare index value G of 0.6 or less measured using the above-described second method (steps S210 to S290, including step S265) as a distance index r = 8. It has the characteristic of being.
　防眩性指標値Ｒは、０．６以上であることが好ましく、０．８以上であることがより好ましい。 The antiglare index value R is preferably 0.6 or more, and more preferably 0.8 or more.
　また、ぎらつき指標値Ｇは、０．５以下であることが好ましく、０．４以下であることがより好ましく、０．３以下であることがさらに好ましい。 The glare index value G is preferably 0.5 or less, more preferably 0.4 or less, and further preferably 0.3 or less.
　次に、各種透明基体を用いて実施した、防眩性評価およびぎらつき評価の結果について説明する。 Next, the results of antiglare evaluation and glare evaluation performed using various transparent substrates will be described.
　（防眩性評価について）
　各種方法で第１の表面がアンチグレア処理された透明基体の防眩性を、以下のような方法で評価した。 (About anti-glare evaluation)
The antiglare property of the transparent substrate whose first surface was antiglare treated by various methods was evaluated by the following methods.
　アンチグレア処理として、フロスト処理、エッチング処理、サンドブラスト処理、ラッピング処理、またはシリカコート処理を採用した。また、透明基体には、アルミノシリケートガラスを使用した。 As the antiglare treatment, a frost treatment, an etching treatment, a sand blast treatment, a lapping treatment, or a silica coating treatment was adopted. In addition, aluminosilicate glass was used for the transparent substrate.
　まず、各透明基体を、第１の表面（すなわちアンチグレア処理された表面）の側から目視で観察し、防眩性をレベル１～レベル１２までの１２段階で評価した。なお、観察方向は、透明基体の厚さ方向に対して、２０゜の方向とした。 First, each transparent substrate was visually observed from the first surface (that is, antiglare-treated surface) side, and antiglare property was evaluated in 12 stages from level 1 to level 12. The observation direction was 20 ° with respect to the thickness direction of the transparent substrate.
　次に、変角光度計（ＧＣ５０００Ｌ：日本電色工業社製）を用いて、前述のステップＳ１１０～ステップＳ１３０に示したような操作を実施して、式（１）から、各透明基体の防眩性指標値Ｒを算定した。 Next, using a goniophotometer (GC5000L: manufactured by Nippon Denshoku Industries Co., Ltd.), the operations as shown in Steps S110 to S130 described above are performed, and the formula (1) is used to prevent each transparent substrate. The dazzling index value R was calculated.
　図８には、各透明基体において得られた、目視による防眩性の評価レベル（縦軸）と、防眩性指標値Ｒ（横軸）の間の関係の一例を示す。 FIG. 8 shows an example of the relationship between the visually evaluated antiglare evaluation level (vertical axis) and the antiglare index value R (horizontal axis) obtained for each transparent substrate.
　図８から、両者の間には、正の相関関係があることがわかる。 FIG. 8 shows that there is a positive correlation between the two.
　この結果は、防眩性指標値Ｒが観察者の目視による反射像拡散性の評価レベルの傾向と対応し、従って防眩性指標値Ｒを用いて、透明基体の反射像拡散性を判断できることを示唆する。換言すれば、防眩性指標値Ｒを使用することにより、透明基体の反射像拡散性を、客観的かつ定量的に判断できると言える。 This result shows that the anti-glare index value R corresponds to the tendency of the evaluation level of the reflected image diffusivity visually observed by the observer, and therefore the anti-glare index value R can be used to determine the reflected image diffusivity of the transparent substrate. To suggest. In other words, by using the antiglare index value R, it can be said that the reflected image diffusibility of the transparent substrate can be objectively and quantitatively determined.
　（ぎらつきの評価について）
　次に、前述の防眩性評価で使用した各種透明基体を使用して、これらの透明基体のぎらつきを、以下のような方法で評価した。 (About evaluation of glare)
Next, using the various transparent substrates used in the above-described evaluation of antiglare properties, the glare of these transparent substrates was evaluated by the following method.
　まず、各透明基体を表示装置（ｉＰａｄ（登録商標）、解像度２６４ｐｐｉ）の上に直接配置する。この際には、各透明基体の第１の表面（すなわちアンチグレア処理された表面）が、観察者側となるようにして、透明基体を表示装置上に配置した。なお、表示装置から表示される像は、緑色単色の像とし、像の寸法は、１９．６ｃｍ×１４．６ｃｍとした。 First, each transparent substrate is directly arranged on a display device (iPad (registered trademark), resolution 264 ppi). At this time, the transparent substrate was placed on the display device such that the first surface of each transparent substrate (that is, the antiglare-treated surface) was on the viewer side. The image displayed from the display device was a green monochromatic image, and the size of the image was 19.6 cm × 14.6 cm.
　次に、この状態で、各透明基体を第１の表面側から目視で観察し、ぎらつきをレベル０～レベル１０までの１１段階で評価した。レベル０は、ぎらつきがほとんど認められないことを表し、レベル１０は、ぎらつきが極めて顕著であることを表す。また、この間のレベル値は、数値が大きいほど、ぎらつきが大きくなる傾向にある。 Next, in this state, each transparent substrate was visually observed from the first surface side, and glare was evaluated in 11 stages from level 0 to level 10. Level 0 represents little glare, and level 10 represents very significant glare. Further, the level value during this time tends to increase the glare as the numerical value increases.
　次に、ＳＭＳ－１０００装置（Ｄｉｓｐｌａｙ－Ｍｅｓｓｔｅｃｈｎｉｋ＆Ｓｙｓｔｅｍｅ社製）を用いて、前述のステップＳ２１０～ステップＳ２９０（ステップＳ２６５を含む）に示したような操作を実施して、式（３）から、各透明基体のぎらつき指標値Ｇを算定した。なお、基準用のアンチグレア処理された透明基体としては、ＶＲＤ１４０アンチグレア処理ガラス（旭硝子株式会社製）を使用した。 Next, using the SMS-1000 apparatus (manufactured by Display-Messtechnik & System), the operations as shown in steps S210 to S290 (including step S265) described above are performed, and each transparent The glare index value G of the substrate was calculated. Note that VRD140 antiglare-treated glass (manufactured by Asahi Glass Co., Ltd.) was used as the reference antiglare-treated transparent substrate.
　表示装置には、前述のｉＰａｄ（登録商標）を使用し、固体撮像素子と透明基体との間の距離ｄは、５４０ｍｍとした。この距離ｄは、距離指数ｒで表すと、ｒ＝１０．８に相当する。 The aforementioned iPad (registered trademark) was used for the display device, and the distance d between the solid-state imaging device and the transparent substrate was 540 mm. This distance d corresponds to r = 10.8 when expressed by a distance index r.
　図９には、各透明基体において得られた、ぎらつき指標値Ｇ（縦軸）と、目視によるぎらつきのレベル（横軸）の間の関係の一例を示す。 FIG. 9 shows an example of the relationship between the glare index value G (vertical axis) and the visual glare level (horizontal axis) obtained for each transparent substrate.
　図９から、両者の間には、正の相関関係があることがわかる。 FIG. 9 shows that there is a positive correlation between the two.
　この結果は、ぎらつき指標値Ｇが観察者の目視によるぎらつきの判定結果の傾向と対応し、従ってぎらつき指標値Ｇを用いて、透明基体のぎらつきを判断できることを示唆する。換言すれば、ぎらつき指標値Ｇを使用することにより、透明基体のぎらつきを、客観的かつ定量的に判断できると言える。 This result suggests that the glare index value G corresponds to the tendency of the determination result of the glare visually observed by the observer, and therefore the glare index value G can be used to determine the glare of the transparent substrate. In other words, it can be said that the glare of the transparent substrate can be objectively and quantitatively determined by using the glare index value G.
　このように、防眩性指標値Ｒおよびぎらつき指標値Ｇを、それぞれ、透明基体の防眩性およびぎらつきの定量的な指標として使用可能であることが確認された。 Thus, it was confirmed that the antiglare index value R and the glare index value G can be used as quantitative indexes for the antiglare property and the glare of the transparent substrate, respectively.
　本発明は、例えば、ＬＣＤ装置、ＯＬＥＤ装置、ＰＤＰ装置、およびタブレット型表示装置のような、各種表示装置等に設置される透明基体の光学特性評価に利用できる。 The present invention can be used for optical characteristic evaluation of a transparent substrate installed in various display devices such as an LCD device, an OLED device, a PDP device, and a tablet display device.
　また、本願は２０１４年５月１４日に出願した日本国特許出願２０１４－１００３４３号に基づく優先権を主張するものであり同日本国出願の全内容を本願に参照により援用する。 In addition, this application claims priority based on Japanese Patent Application No. 2014-100343 filed on May 14, 2014, the entire contents of which are incorporated herein by reference.
　２１０　　透明基体
　２１２　　第１の表面
　２１４　　第２の表面
　３００　　測定装置
　３５０　　光源
　３６２　　第１の光
　３６４　　反射光
　３７０　　検出器
　４１０　　第１の画像
　４２０－１～４２０－９　対応領域
　４３０　　第１の輝度分布
　９００　　透明基体
　９０２　　第１の表面
　９０４　　第２の表面
　ｑｉ　　　輝度分布成分 210 transparent substrate 212 first surface 214 second surface 300 measuring device 350 light source 362 first light 364 reflected light 370 detector 410 first image 420-1 to 420-9 corresponding region 430 first luminance distribution 900 Transparent substrate 902 first surface 904 second surface q i luminance distribution component

Claims (10)

  1. 　透明基体の光学特性を評価する方法であって、
    　第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体の定量化された防眩性指標値を取得するステップと、
    　前記透明基体の定量化されたぎらつき指標値を取得するステップと、
    　を順不同に有し、
    　前記定量化された防眩性指標値は、
    　　（ａ）第１および第２の表面を有する透明基体の前記第１の表面側から、前記透明基体の厚さ方向に対して２０゜の方向に第１の光を照射し、前記第１の表面で反射する２０゜正反射光の輝度を測定するステップと、
    　　（ｂ）前記第１の表面により反射される反射光の受光角度を－２０゜～＋６０°の範囲で変化させ、前記第１の表面で反射される全反射光の輝度を測定するステップと、
    　　（ｃ）以下の式（１）から、防眩性指標値Ｒを算定するステップと
     
    　　防眩性指標値Ｒ＝
    　　　　（全反射光の輝度－２０゜正反射光の輝度）／（全反射光の輝度）　　式（１）
     
    　により得られ、
    　前記定量化されたぎらつき指標値は、
    　　（Ａ）前記透明基体を、前記第２の表面が表示装置の側になるようにして、前記表示装置の上に配置するステップと、
    　　（Ｂ）前記表示装置をオンにした状態で、固体撮像素子を用いて前記透明基体を撮影し、第１の画像を取得するステップであって、前記固体撮像素子と前記透明基体の間の距離をｄとし、前記固体撮像素子の焦点距離をｆとしたとき、撮影の際の距離指数ｒ（＝ｄ／ｆ）は、８以上であるステップと、
    　　（Ｃ）前記取得された第１の画像から、第１の輝度分布を形成するステップと、
    　　（Ｄ）前記透明基体を、前記第２の表面と略平行な方向に動かし、前記透明基体を前記表示装置に対して移動させるステップと、
    　　（Ｅ）前記（Ｂ）および（Ｃ）のステップを繰り返し、取得された第２の画像から、第２の輝度分布を形成するステップと、
    　　（Ｆ）前記第１の輝度分布と前記第２の輝度分布の差分から、差分輝度分布ΔＳを求めるステップと、
    　　（Ｇ）前記差分輝度分布ΔＳから、平均輝度分布ΔＳａｖｅおよび分散σを算定するとともに、以下の式（２）から、出力値Ａを得るステップと、
     
    　　出力値Ａ＝分散σ／平均輝度分布ΔＳａｖｅ　　式（２）
     
    　　（Ｈ）前記（Ａ）～（Ｇ）のステップを、基準用のアンチグレア処理された透明基体で実施して、出力値Ａの代わりに、参照出力値Ｑを得るステップであって、該（Ｈ）のステップは、前記（Ａ）～（Ｇ）のステップの前、または前記（Ａ）～（Ｇ）のステップと並列に実施されるステップと、
    　　（Ｉ）以下の式（３）から、ぎらつき指標値Ｇを求めるステップと、
     
    　　ぎらつき指標値Ｇ＝（出力値Ａ）／（参照出力値Ｑ）　　　式（３）
     
    　により得られることを特徴とする方法。     A method for evaluating the optical properties of a transparent substrate,
    Obtaining a quantified anti-glare index value of a transparent substrate having first and second surfaces, the first surface being anti-glare treated;
    Obtaining a quantified glare index value of the transparent substrate;
    In random order,
    The quantified anti-glare index value is
    (A) The first light is irradiated from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 ° with respect to the thickness direction of the transparent substrate; Measuring the brightness of the 20 ° specularly reflected light reflected from the surface;
    (B) changing the light receiving angle of the reflected light reflected by the first surface in a range of −20 ° to + 60 ° and measuring the luminance of the total reflected light reflected by the first surface;
    (C) calculating the antiglare index value R from the following equation (1);
    Anti-glare index value R =
    (Brightness of total reflected light-brightness of 20 ° regular reflected light) / (Brightness of total reflected light) Equation (1)

    Obtained by
    The quantified glare index value is
    (A) placing the transparent substrate on the display device with the second surface facing the display device;
    (B) A step of photographing the transparent substrate using a solid-state imaging device and obtaining a first image with the display device turned on, and a distance between the solid-state imaging device and the transparent substrate. Where d is the distance index r (= d / f) at the time of shooting, where d is the focal length of the solid-state imaging device, and f is
    (C) forming a first luminance distribution from the acquired first image;
    (D) moving the transparent substrate in a direction substantially parallel to the second surface, and moving the transparent substrate with respect to the display device;
    (E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image;
    (F) obtaining a difference luminance distribution ΔS from a difference between the first luminance distribution and the second luminance distribution;
    (G) calculating an average luminance distribution ΔS ave and variance σ from the difference luminance distribution ΔS, and obtaining an output value A from the following equation (2):

    Output value A = dispersion σ / average luminance distribution ΔS ave equation (2)

    (H) Steps (A) to (G) are performed on a reference anti-glare transparent substrate to obtain a reference output value Q instead of the output value A. ) Is performed before the steps (A) to (G) or in parallel with the steps (A) to (G).
    (I) A step of obtaining a glare index value G from the following equation (3):

    Glitter index value G = (output value A) / (reference output value Q) Equation (3)

    A method characterized by being obtained by:
  2. 　前記（Ｇ）のステップの前に、前記差分輝度分布ΔＳから、前記表示装置に由来する成分をフィルタ除去して、実効差分輝度分布ΔＳｅを得るステップが実施され、
    　前記（Ｇ）のステップでは、前記差分輝度分布ΔＳの代わりに、前記実効差分輝度分布ΔＳｅが使用される、請求項１に記載の方法。     Before the step (G), a step of filtering out components derived from the display device from the difference luminance distribution ΔS to obtain an effective difference luminance distribution ΔS e is performed.
    The step in the (G), instead of the difference luminance distribution [Delta] S, the effective difference luminance distribution [Delta] S e is used, the method according to claim 1.
  3. 　前記防眩性指標値は、ゴニオメータを用いて取得されることを特徴とする請求項１または２に記載の方法。 The method according to claim 1 or 2, wherein the antiglare index value is obtained using a goniometer.
  4. 　前記表示装置は、ＬＣＤ装置、ＯＬＥＤ装置、ＰＤＰ装置、およびタブレット型表示装置からなる群から選択された一つであることを特徴とする請求項１乃至３のいずれか一つに記載の方法。 The method according to any one of claims 1 to 3, wherein the display device is one selected from the group consisting of an LCD device, an OLED device, a PDP device, and a tablet display device.
  5. 　前記表示装置は、１３２ｐｐｉ以上の解像度を有することを特徴とする請求項１乃至４のいずれか一つに記載の方法。 The method according to claim 1, wherein the display device has a resolution of 132 ppi or more.
  6. 　前記透明基体は、ソーダライムガラスまたはアルミノシリケートガラスで構成されることを特徴とする請求項１乃至５のいずれか一つに記載の方法。 The method according to any one of claims 1 to 5, wherein the transparent substrate is made of soda lime glass or aluminosilicate glass.
  7. 　前記透明基体は、第１および第２の表面のうちの少なくとも一方が、化学強化処理されていることを特徴とする請求項６に記載の方法。 The method according to claim 6, wherein at least one of the first and second surfaces of the transparent substrate is chemically strengthened.
  8. 　前記アンチグレア処理は、前記透明基体の第１の表面に、フロスト処理、エッチング処理、サンドブラスト処理、ラッピング処理、およびシリカコート処理からなる群から選択された、少なくとも一つの処理方法を適用することにより実施される、請求項１乃至７のいずれか一つに記載の方法。 The antiglare treatment is performed by applying at least one treatment method selected from the group consisting of a frost treatment, an etching treatment, a sand blast treatment, a lapping treatment, and a silica coating treatment to the first surface of the transparent substrate. The method according to any one of claims 1 to 7, wherein:
  9. 　第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体であって、
    　前記請求項１乃至５のいずれか一つに記載の方法で評価した際に、
    　前記防眩性指標値Ｒが０．４以上であり、
    　前記ぎらつき指標値Ｇが０．６以下であることを特徴とする透明基体。     A transparent substrate having first and second surfaces, wherein the first surface is antiglare treated,
    When evaluated by the method according to any one of claims 1 to 5,
    The antiglare index value R is 0.4 or more,
    The transparent substrate, wherein the glare index value G is 0.6 or less.
  10. 　第１および第２の表面を有し、前記第１の表面がアンチグレア処理された透明基体であって、
    　前記請求項１乃至５のいずれか一つに記載の方法で評価した際に、
    　前記防眩性指標値Ｒが０．４以上であり、
    　前記ぎらつき指標値Ｇが０．３以下であることを特徴とする透明基体。     A transparent substrate having first and second surfaces, wherein the first surface is antiglare treated,
    When evaluated by the method according to any one of claims 1 to 5,
    The antiglare index value R is 0.4 or more,
    The transparent substrate, wherein the glare index value G is 0.3 or less.
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