KR20170008224A - Method for evaluating optical characteristic of transparent substrate, and transparent substrate - Google Patents

Abstract

A method of evaluating an optical characteristic of a transparent gas, comprising the steps of: determining a quantified anti-glare index value (R) of an anti-glare-treated transparent gas; determining a quantified glare index value (G) .

Description

METHOD FOR EVALUATING OPTICAL CHARACTERISTIC OF TRANSPARENT SUBSTRATE, AND TRANSPARENT SUBSTRATE,

The present invention relates to a method for evaluating optical properties of a transparent substrate.

In general, on a display device such as a liquid crystal display (LCD) device having pixels, a protective cover composed of a transparent substrate is disposed for protecting the display device.

However, in the case where such a transparent substrate is provided on a display device, when the display image of the display device is intended to be viewed through a transparent substrate, there is a case where the ambient light often appears. If such visual impression occurs in the transparent gas, the viewer of the display image becomes difficult to visually recognize the display image, and the impression is unpleasant.

Thus, in order to suppress such impurities, the anti-glare treatment may be applied to the surface of the transparent substrate.

Further, Patent Document 1 shows a method of evaluating the non-penetration of the display device by using a special device.

Japanese Patent Application Laid-Open No. 2007-147343

As described above, the anti-glare treatment is often applied to the transparent substrate in order to suppress non-exposure of the ambient light.

However, in an actual transparent substrate, it may be desired to simultaneously grasp characteristics such as flicker and flicker in addition to the effect of suppressing ambient light.

However, heretofore, the method of evaluating both the flash-time and the flashing of the transparent gas has not been known so far. Particularly, regarding the flashing of the transparent gas, it is difficult to say that the evaluation method has been sufficiently established so far, and it is difficult to quantitatively evaluate it.

In addition, as an apparatus for evaluating the glare of a transparent substrate, a recent SMS-1000 apparatus (manufactured by Display-Messtechnik & Systeme) has attracted attention. In this SMS-1000 apparatus, the glare of the transparent substrate can be evaluated by analyzing a part of the image (luminance) of the transparent substrate photographed via the solid-state image sensor.

However, according to the findings of the present inventors, it has been confirmed that, in the evaluation by the SMS-1000 apparatus, measurement results of proper glare are sometimes not obtained. That is, in the visual observation, no significant flashing is confirmed, but in the evaluation by the SMS-1000 apparatus, there are cases in which the transparent gas is judged to exhibit remarkable flashing, and vice versa.

As described above, there is still a need for a technique for properly grasping both the flashing property of the transparent substrate and the flashing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to provide an evaluation method capable of appropriately evaluating both the flashing property and flashing of an anti-glare-treated transparent substrate.

In the present invention, as a method for evaluating the optical characteristics of a transparent substrate,

Obtaining a quantified anti-glare index value of the transparent substrate having the first and second surfaces, the anti-glare treatment of the first surface,

A step of acquiring a quantified glare index value of the transparent substrate in a non-sequential manner,

The quantified anti-

(a) irradiating first light from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 占 with respect to the thickness direction of the transparent substrate; A step of measuring a luminance of regularly reflected light,

(b) changing a light receiving angle of the reflected light reflected by the first surface in a range of -20 to +60 degrees, and measuring a luminance of the entire reflected light reflected by the first surface;

(c) a step of calculating the value D of the dazzling index from the following formula (1); and

Flammability Index (R) =

(Luminance of total reflected light-luminance of regularly reflected light of -20 占 / luminance of total reflected light)

Equation (1)

Lt; / RTI >

The quantified glare indicator value

(A) placing the transparent substrate on the display device so that the second surface is on the display device side, and

(B) obtaining a first image by photographing the transparent substrate using the solid-state image pickup element in a state in which the display device is turned on, wherein a distance between the solid-state image pickup element and the transparent substrate is d , And the distance index r (= d / f) at the time of photographing when the focal length of the solid-state image sensor is f,

(C) forming a first luminance distribution from the acquired first image,

(D) moving the transparent substrate with respect to the display device by moving the transparent substrate in a direction substantially parallel to the second surface,

(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image,

(F) obtaining a difference luminance distribution (? S) from a difference between the first luminance distribution and the second luminance distribution;

(G) calculating an average luminance distribution (ΔS _ave ) and a variance (σ) from the differential luminance distribution (ΔS) and obtaining an output value (A) from the following expression (2)

Output value (A) = dispersion (?) / Average luminance distribution (? S _ave )

(H) A step of performing the above steps (A) to (G) with a transparent gas subjected to a reference anti-glare treatment to obtain a reference output value Q instead of the output value A, The step includes steps performed before the steps (A) to (G) or in parallel with the steps (A) to (G)

(I), a step of obtaining the flashing index value G from the following formula (3)

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

Lt; RTI ID = 0.0 > a < / RTI >

In the present invention, as the transparent substrate having the first and second surfaces and having the first surface subjected to the anti-glare treatment,

When evaluated by the above-described method according to the present invention,

(R) is 0.4 or more,

And the flashing index value (G) is 0.6 or less.

According to the present invention, it is possible to provide an evaluation method capable of appropriately evaluating both the anti-glare property and the flashing property of the anti-glare-treated transparent substrate.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view schematically showing a flow of a method for evaluating the scattering property of a transparent gas according to an embodiment of the present invention. FIG.
Fig. 2 is a diagram schematically showing an example of a measuring apparatus used when acquiring the value of the gas turbidity index. Fig.
3 is a view schematically showing a flow of a method of evaluating flashing of a transparent substrate according to an embodiment of the present invention.
4 is a diagram schematically showing a first image obtained in a step of a method for evaluating flashing of a transparent substrate.
5 is a diagram schematically showing a first luminance distribution obtained in a step of a method for evaluating flashing of a transparent substrate.
Fig. 6 is a diagram showing an example of the relationship between the scattering index value R (horizontal axis) and the flashing index value G (vertical axis) obtained in various transparent substrates.
7 is a diagram schematically showing a transparent substrate according to an embodiment of the present invention.
Fig. 8 is a graph showing an example of the relationship between the level (vertical axis) of visually observable scattering property obtained on each transparent substrate and the scattering index value R (horizontal axis).
9 is a graph showing an example of the relationship between the flashing index value G (vertical axis) and the level of flashing by the naked eye (horizontal axis) obtained for each transparent substrate.

Hereinafter, the present invention will be described in detail.

As described above, there is a case where it is desired to grasp the characteristics of the anti-glare and transparency of the transparent substrate. However, in the present situation, a method of objectively evaluating both the flash-time and the flashing of the transparent gas is scarcely confirmed.

In particular, since there are various methods for applying the anti glare treatment to the transparent substrate, there are various types of surfaces of the anti-glare treated transparent substrate. It is very difficult to uniformly evaluate the flicker and flicker of the transparent gas having various surfaces with the same index.

For example, recently, as an apparatus for evaluating flashing of a transparent gas, an SMS-1000 apparatus has attracted attention. However, according to the findings of the present inventors, it has been confirmed that, in the evaluation by the SMS-1000 apparatus, measurement results of proper glare are sometimes not obtained. That is, even in the case of a transparent gas whose significant glare is not confirmed in the visual observation, there are cases in which the transparent gas is judged to show a large flashing in the evaluation by the SMS-1000 apparatus, and vice versa .

Thus, even if attention is paid only to the flashing of the transparent substrate, it is difficult to say that a sufficiently effective measurement method has yet to be established. In addition, there is almost no evaluation method that focuses on both the flash-time and the flashing of the transparent gas.

On the other hand, in the present invention, as a method for evaluating the optical characteristics of the transparent substrate,

Obtaining a quantified anti-glare index value of the transparent substrate having the first and second surfaces, the anti-glare treatment of the first surface,

A step of acquiring a quantified glare index value of the transparent substrate in a non-sequential manner,

The quantified anti-

(a) irradiating first light from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 占 with respect to the thickness direction of the transparent substrate; A step of measuring a luminance of regularly reflected light,

(b) changing a light receiving angle of the reflected light reflected by the first surface in a range of -20 to +60 degrees, and measuring a luminance of the entire reflected light reflected by the first surface;

(c) a step of calculating the value D of the dazzling index from the following formula (1); and

Flammability Index (R) =

(Luminance of all reflected light-luminance of regularly reflected light of -20 DEG) / (luminance of total reflected light)

Lt; / RTI >

The quantified glare indicator value

(A) placing the transparent substrate on the display device so that the second surface is on the display device side, and

(B) obtaining a first image by photographing the transparent substrate using the solid-state image pickup element in a state in which the display device is turned on, wherein a distance between the solid-state image pickup element and the transparent substrate is d , And the distance index r (= d / f) at the time of photographing when the focal length of the solid-state image sensor is f,

(C) forming a first luminance distribution from the acquired first image,

(D) moving the transparent substrate with respect to the display device by moving the transparent substrate in a direction substantially parallel to the second surface,

(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image,

(F) obtaining a difference luminance distribution (? S) from a difference between the first luminance distribution and the second luminance distribution;

(G) calculating an average luminance distribution (ΔS _ave ) and a variance (σ) from the differential luminance distribution (ΔS) and obtaining an output value (A) from the following expression (2)

Output value (A) = dispersion (?) / Average luminance distribution (? S _ave )

(H) A step of performing the above steps (A) to (G) with a transparent gas subjected to a reference anti-glare treatment to obtain a reference output value Q instead of the output value A, The step includes steps performed before the steps (A) to (G) or in parallel with the steps (A) to (G)

(I), a step of obtaining the flashing index value G from the following formula (3)

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

Lt; RTI ID = 0.0 > a < / RTI >

In the method of evaluating the optical characteristics of the transparent substrate according to the present invention, as described in detail below, the anti-glare-treated transparent substrate is properly evaluated for both the scattering property and the flashing property, .

Further, in the method according to the present invention, the numerical value is used as the scattering property and the flashing of the transparent substrate. Therefore, with respect to the flashing property and the flashing, it is possible to objectively and quantitatively judge these optical characteristics without regard to the subjective or preconstructed view of the observer.

(Regarding one embodiment of the method for evaluating the optical characteristics of the transparent substrate according to the present invention)

Next, with reference to the drawings, one embodiment of a method for evaluating each of the opacity and flashing of the transparent gas which can be used in the method according to the present invention will be described.

(Evaluation method of flammability)

Fig. 1 schematically shows a flow of a method for evaluating the scattering property of a transparent gas according to an embodiment of the present invention.

As shown in Fig. 1, a method (hereinafter also referred to as " first method ") for evaluating the light-

(a) irradiating first light from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 占 with respect to the thickness direction of the transparent substrate, and (Hereinafter also referred to as " 20 ° regular reflection light ") (step S110)

(b) a light receiving angle of the reflected light reflected by the first surface is changed in a range of -20 to +60 degrees, and the first light reflected by the first surface (hereinafter also referred to as " total reflected light " A step of measuring luminance (step S120)

(c) From the following equation (1), the step of calculating the dazzling index value R (step S130)

Flammability Index (R) =

(Luminance of all reflected light-luminance of regularly reflected light of -20 DEG) / (luminance of total reflected light)

Respectively.

Hereinafter, each step will be described.

(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 gas may be, for example, glass or plastic.

When the transparent gas is composed of glass, the composition of the glass is not particularly limited. The glass may be, for example, soda lime glass or aluminosilicate glass.

When the transparent gas is made of glass, the first and / or second surfaces may be chemically strengthened.

Here, the chemical strengthening treatment refers to a treatment of immersing a glass substrate in a molten salt containing an alkali metal to remove an alkali metal (ion) having a small ionic radius present on the outermost surface of the glass substrate, Metal (ion). In the chemical strengthening treatment method, alkali metal (ion) having a larger ionic radius than the original atom is disposed on the surface of the processed glass substrate. Therefore, compressive stress can be applied to the surface of the glass substrate, whereby the strength (in particular, the crack strength) of the glass substrate is improved.

For example, when the glass substrate comprises sodium ions (Na < ^{+ &} gt ^; ), the sodium ions are replaced by, for example, potassium ions (K < ⁺ & gt ^; ) by chemical strengthening treatment. Or, for example, in the case that the glass substrate comprises a lithium ion (Li ^+), by the chemical strengthening treatment, a lithium ion, for example, replaced with sodium ions (Na ⁺⁾ and / or a potassium ion (K ⁺⁾ .

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, for example, a polycarbonate substrate.

Also, before step S110, a step of anti-glare processing the first surface of the transparent substrate is performed. The method of anti-glare treatment is not particularly limited. The anti-glare treatment may be, for example, a frost treatment, an etching treatment, a sandblasting treatment, a lapping treatment, a silica coating treatment or the like.

In the method of measuring the gas turbidity according to the embodiment of the present invention, various transparent gases can be uniformly evaluated by using a quantitative index value (ruggedness index value R) indicating the gas turbidity of the transparent gas. Therefore, various methods can be employed as the anti-glare processing method.

The first surface of the transparent substrate after the anti-glare treatment may have a surface roughness (arithmetic mean roughness (Ra)) in the range of 0.05 mu m to 1.0 mu m, for example.

Next, from the first surface side of the prepared transparent substrate, the first light is irradiated toward the direction of 20 占 0.5 占 with respect to the thickness direction of the transparent substrate. The first light is reflected at the first surface of the transparent substrate. Among the reflected light, 20 ° regularly reflected light is received, and its luminance is measured to be referred to as " luminance of 20 ° regularly reflected light ".

(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 be referred to as " luminance of the entire reflected light ".

(Step S130)

Next, from the following equation (1), the value of the non-uniformity index R is calculated:

Flammability Index (R) =

(Luminance of all reflected light-luminance of regularly reflected light of -20 DEG) / (luminance of total reflected light)

As described later, the gauges index R correlates with the judgment result of the visibility of the observer's eyesight, and it is confirmed that the gauges index R exhibits a behavior close to that of a person's sight. For example, a transparent gas having a large value (a value close to 1) of the zigzagging index value R is excellent in the retardation property and the transparent gas having a small value of the zigzagging index value R, There is a tendency to lose sight. Therefore, the anti-glare index value R can be used as a quantitative indicator in determining the anti-glare properties of the transparent gas.

Fig. 2 schematically shows an example of a measuring apparatus used when acquiring the ruggedness index R shown in the above-mentioned equation (1).

2, the measuring apparatus 300 has a light source 350 and a detector 370, and the transparent substrate 210 is disposed in the measuring apparatus 300. As shown in Fig. The transparent substrate 210 has a first surface 212 and a second surface 214. The light source 350 emits the first light 362 toward the transparent substrate 210. The detector 370 receives the reflected light 364 reflected at the first surface 212 and detects the luminance.

The transparent substrate 210 is disposed such that the first surface 212 is on the light source 350 and the detector 370 side. Therefore, the first light detected by the detector 370 is the reflected light 364 reflected by the transparent substrate 210. [ When the surface of one side of the transparent substrate 210 is anti-glare-treated, the anti-glare-treated surface becomes the first surface 212 of the transparent substrate 210. That is, in this case, the transparent substrate 210 is placed in the measuring apparatus 300 so that the surface on which the anti-glare treatment is performed becomes the light source 350 and the detector 370 side.

The first light 362 is irradiated at an angle inclined by 20 DEG with respect to the thickness direction of the transparent substrate 210. [ Also, in the present application, a range of 20 deg. 0.5 deg. Is defined as an angle of 20 deg. In consideration of the error of the measuring apparatus.

In this measuring apparatus 300, the first light 362 is irradiated from the light source 350 toward the transparent substrate 210, and the detector 370 arranged so that the light receiving angle? And detects the regularly reflected light 364 reflected from the first surface 212 of the transparent substrate 210. Thus, " 20 ° regular reflection light " is detected.

Next, in the detector 370, the light receiving angle [phi] for measuring the reflected light 364 is changed in the range of -20 [deg.] To + 60 [deg.], And the same operation is performed.

The luminance 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 in the range of the light receiving angle? = -20 to +60 degrees, Sum up.

Here, the negative (-) of the light receiving angle? Indicates that the light receiving angle is on the incident light side with respect to the object surface (the first surface in this example) to be evaluated and the plus (+ Indicates that the light receiving angle is not on the incident light side as compared with the normal line of the object surface.

From the luminance of the obtained 20 ° regular reflection light and the luminance of the totally reflected light, it is possible to obtain the anti-scattering index value R of the transparent substrate 210 by the above-mentioned equation (1). Such a measurement can be easily carried out by using a commercially available goniometer (a goniometer).

Also, the irradiation angle of the first light can be suitably selected in the range of 60 DEG to 5 DEG. However, in the present application, 20 占 is selected as the irradiation angle of the first light from the viewpoint of showing a good correlation between the blurring evaluation by visual observation and the quantitative evaluation.

(Against glare indicator)

Fig. 3 schematically shows a flow of a method for evaluating flashing of a transparent gas according to an embodiment of the present invention.

As shown in Fig. 3, a method (hereinafter referred to as " second method ") for evaluating the flashing of the transparent substrate,

(A) a step of placing a transparent substrate having first and second surfaces on the display device so that the second surface is on the display device side (step S210)

(B) obtaining a first image by photographing the transparent substrate using the solid-state image pickup element in a state in which the display device is turned on, wherein a distance between the solid-state image pickup element and the transparent substrate is d (Step S220) in which the distance index r (= d / f) at the time of photographing is 8 or more when the focal length of the solid-state image sensor is f,

(C) a step of 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); and

(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image (step S250)

(F) a step of obtaining a differential luminance distribution (? S) from the difference between the first luminance distribution and the second luminance distribution (step S260)

(G) A step (step S270) of calculating the average luminance distribution (? S _ave ) and the variance (?) From the differential luminance distribution (? S) and obtaining the output value (A) and,

Output value (A) = dispersion (?) / Average luminance distribution (? S _ave )

(H) a step (S280) of performing the steps (A) to (G) with a transparent gas subjected to reference anti-glare treatment to obtain a reference output value Q instead of the output value A,

(Step S290) of obtaining the flashing index value G from the following equation (3)

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

.

Hereinafter, each step will be described in detail.

(Step S210)

First, a transparent substrate having first and second surfaces facing each other is prepared. The transparent substrate has an anti-glare treatment on the first surface.

The material, composition, and the like of the transparent substrate are the same as those shown in step S110 described above, and will not be described here.

However, as described above, there has been conventionally a problem in that, not only between a single anti-glare treatment method, such as a change in conditions in an etching treatment, but also a flashing of a transparent substrate having various different surfaces according to a plurality of existing anti- It was difficult to evaluate uniformly with the same index.

However, in the flashing evaluation method according to the embodiment of the present invention, as will be described later, by using a quantitative index value (flashing index value G) indicating the flashing of the transparent substrate, It can be evaluated uniformly. Therefore, it should be noted that the flashing evaluation method according to the embodiment of the present invention is also useful as a means for selecting a processing method of anti-glare processing.

Next, a display device is prepared. The display device is not particularly limited as long as it has pixels (pixels). 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 type display device. The resolution of the display device is preferably, for example, 132 ppi or higher, more preferably 186 ppi or higher, and more preferably 264 ppi or higher.

Next, a transparent substrate is disposed on the display device. At this time, the transparent substrate is disposed on the display device so that the second surface is the display device side.

(Step S220)

Next, the transparent substrate is photographed from the first surface side using the solid-state image pickup device in a state in which the display device is turned ON (i.e., the image is displayed), and the image of the transparent substrate 1 image).

The distance d between the solid-state image sensor and the transparent substrate is set to a predetermined value.

Further, in the present application, the distance index r is used as an index corresponding to the distance d between the solid-state image pickup device and the transparent substrate. Here, the distance index r is represented by the following formula (4) using the focal length f of the solid-state image pickup element and the distance d between the solid-state image pickup element and the transparent substrate:

(Distance d between the solid-state imaging element and the transparent substrate) / (focal length f of the solid-state imaging element) Equation (4)

Further, in the present application, the distance index r is 8 or more.

This is because if the distance index r is smaller than 8, the distance d between the solid-state image sensing device and the transparent substrate becomes small, and the transparent gas becomes susceptible to the shape of the first anti-glare surface. Therefore, by setting the distance index r to 8 or more, 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 becomes possible to uniformly evaluate the stuttering.

The distance index r is preferably 9 or more, more preferably 10 or more.

The image to be displayed on the display device is preferably a single color (for example, green) image and displayed on the entire display screen of the display device. And the influence of the difference in the viewing method due to the difference in display color is minimized.

As the solid-state image pickup device, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used. In either case, it is preferable to use a digital camera or the like having a high number of pixels.

By this step, for example, a first image 410 schematically shown in Fig. 4 is obtained. In the example shown in Fig. 4, in the first image 410, regions corresponding to nine pixels arranged in 3 rows x 3 columns (hereinafter referred to as corresponding regions 420-1 to 420-9) It is brightly admitted.

In Fig. 4, for the sake of clarity, the corresponding regions 420-1 to 420-9 are shown to be sufficiently separated from each other. However, it should be noted that, in the actual image, the distances between the corresponding regions 420-1 to 420-9 are narrower, and the bright portions in the adjacent corresponding regions may partially overlap each other.

(Step S230)

Next, in step S220, the photographed first image 410 is subjected to image analysis to form a first luminance distribution. 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.

5, the first luminance distribution 430 has a luminance distribution of a substantially normal distribution in each of the regions corresponding to the corresponding regions 420-1 to 420-9 of the first image 410 (Q ₁ to q ₉ ). More generally, the first luminance distribution 430 is represented by a set of i number of luminance distribution components q _i (i is an integer of 2 or more).

It should be noted in Fig. 5 that the luminance distribution components (q ₁ to q ₉ ) appear two-dimensionally (i.e., non-stereoscopically) in order to avoid complication of description.

In order to increase the accuracy of the first luminance distribution 430, the number of first images 410 photographed in step S220 is increased. In step S230, the same image analysis . In this case, after the respective image analysis results are averaged, the first luminance distribution 430 with higher accuracy is obtained.

(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, for example, several millimeters.

(Step S250)

Next, steps S220 to S230 are repeated. That is, in a state in which the display device is turned on, the second image is acquired by the solid-state image pickup device, and the second luminance distribution is formed from the second image.

Also in this step, the number of second images photographed by the solid-state image sensor may be increased in order to increase the accuracy of the second luminance distribution. Thereafter, image analysis is performed on each second image, and the respective image analysis results are averaged to obtain a second luminance distribution with higher accuracy.

In this way, the second luminance distribution is represented by a set of a plurality of luminance distribution components (s _i) (where i is an integer of 2 or greater) can be obtained. Further, the luminance distribution components (s _i) is made up of the same number as the luminance distribution component _(i q).

(Step S260)

Next, the differential luminance distribution? S is calculated from the difference between the first luminance distribution and the second luminance distribution. Luminance distribution difference (ΔS), the first luminance distribution, and like the second luminance distribution is represented by a set of approximate luminance distribution component of the normal distribution shape (t _i) (where i is an integer of 2 or more).

(Step S270)

Next, the average luminance distribution (? S _ave ) and the variance (?) Are calculated using the differential luminance distribution (? S) obtained in step S260.

Here, the average luminance distribution (ΔS _ave ) can be obtained by averaging the absolute values of the _i luminance distribution components (t _i ) included in the differential luminance distribution (ΔS). The dispersion can be obtained from the following equation (5) using the _i luminance distribution components (t _i ) and the average luminance distribution (? S _ave ) included in the differential luminance distribution (? S).

The output value A is calculated from the obtained average luminance distribution (? S _ave ) and dispersion (?) By the following expression (2)

Output value (A) = dispersion (?) / Average luminance distribution (? S _ave )

(Step S280)

Next, the steps from step S210 to step S270 are performed using the reference (reference) anti-glare processed transparent substrate. Thus, the reference output value Q is acquired instead of the output value A of the formula (2).

The reference output value Q is required to have a high measurement reproducibility and sufficiently larger than the error per measurement because the flashing index value is represented by the ratio with the reference output value Q obtained in accordance with the below-described formula (3) . In order to easily prepare an anti-glare processed transparent substrate for reference (reference) for giving an appropriate reference output value Q, soda lime glass is a flat glass which is subjected to anti-glare treatment by frost etching, And the mean length (RSm) of the roughness curve elements is not less than 70 占 퐉 and less than 120 占 퐉, and those available as commercial products may be selected.

Here, the 60 degree gloss can be measured as a mirror gloss by a method in accordance with JIS-Z8741. The 60 degree gross value is, for example, 110 or more, and more preferably 120 or more. The average length (RSm) of the roughness curve elements can be measured by a method in accordance with JIS B0601 (2001). The average length RSm of the roughness curve elements is, for example, 70 mu m or more, more preferably 80 mu m or more, further preferably 120 mu m or less and preferably 110 mu m or less.

In one embodiment of the present invention, the reference anti-glare treated transparent substrate satisfying the above-mentioned conditions is a VRD 140 (having a 60 degree gloss value of 140% and an average length RSm of the surface roughness curve element of 85 m) Anti-glare treatment glass (manufactured by Asahi Glass Co., Ltd.) was selected.

The step S280 may be performed before the above-described steps S210 to S270 are performed using the transparent substrate subjected to the anti-glare treatment for evaluation. Alternatively, this step S280 may be performed in parallel with the execution of the steps S210 to S270 in the transparent substrate subjected to the evaluation anti-glare treatment.

(Step S290)

Next, using the output value A and the reference output value Q, the flashing index value G is obtained from the following expression (3): " (1) "

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

The glare index value G is correlated with the judgment result of the glare by the naked eye of the observer as described later, and it is confirmed that the glaze G For example, a transparent substrate having a large glare index value (G) tends to be flashing, while a transparent substrate having a small glare index value (G) tends to be suppressed from flashing. Therefore, the glare index value G can be used as a quantitative index when judging whether or not the transparent gas is flashing.

An example of a method of evaluating the flashing of the transparent substrate has been described above with reference to Figs. 3 to 5. Fig. However, in the present invention, the method of evaluating the flickering of the transparent substrate is not limited to this.

For example, in the above-described flow, between step S260 and step S270, a step of removing a filter derived from the display device from the differential luminance distribution? S (step S265) may be performed. The accuracy of the obtained glare index value G can be further improved by performing the step S270 by using the effective differential luminance distribution (ΔS _e ) obtained by this operation instead of the differential luminance distribution ΔS.

However, this step S265 may be performed when necessary, and is not necessarily required to be performed.

Further, the above-described method for evaluating the glare of the transparent substrate can be easily carried out by using, for example, an SMS-1000 apparatus (manufactured by Display-Messtechnik & Systeme).

By using the above-described flicker-suppressing index value R and the flashing index value G as described above, it becomes possible to quantitatively evaluate the optical characteristics of the anti-glare-treated transparent substrate.

(Evaluation by two indicators)

Next, a method of evaluating two optical characteristics of the transparent substrate at the same time and effects thereof will be described.

Fig. 6 shows an example of a diagram plotting the relationship between the anti-flammability index R (horizontal axis) and the flashing index value G (vertical axis) obtained in the anti-glare-treated transparent substrate by various methods. Here, the distance index (r) at the time of photographing in the flashing evaluation for obtaining this data is 10.8.

In Fig. 6, as the diastolicity index value R of the horizontal axis is larger and the index value of the vertical axis is smaller, the transparency of the transparent substrate is improved and the flickering of the transparent substrate is suppressed.

In Fig. 6, for reference, an ideal transparent gas region having a good flame retardancy and a good anti-flashing property is indicated by a mark " ideal ".

Here, when a candidate transparent substrate is selected from among various transparent substrates in consideration of a single optical property, for example, anti-flashing property, the transparent substrate contained in the region C indicated by the hatched portion in FIG. do. That is, in such a method, a transparent gas having a low resistance to scattering is included in the selected transparent substrate. Similarly, when a transparent substrate is selected in consideration of only the intumescence property, the transparent substrate included in the region D indicated by the hatching in FIG. 6 is evenly selected, and the transparent substrate having a low anti- Throw away.

On the other hand, when the correlation between the flashing index value G and the flashing resistance R as shown in Fig. 6 is used, it is possible to select an appropriate transparent gas in consideration of both optical characteristics at one time. That is, in such a selection method, it is possible to appropriately select the transparent substrate according to the purpose and the use purpose, that is, to select the transparent substrate so as to exhibit the best characteristics with respect to the anti-flicker property and the anti-scattering property.

As described above, in the method according to the embodiment of the present invention, since the two optical characteristics can be quantitatively considered at a time, it becomes possible to more appropriately select the transparent substrate according to the purpose of use, the use, and the like.

Further, in the method according to the present invention, numerical values are used as the scattering index value R and the flashing index value G of the transparent gas. Therefore, with respect to the flashing property and the flashing, it is possible to objectively and quantitatively judge these optical characteristics without regard to the subjective or preconstructed view of the observer.

(A 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.

7 schematically shows a transparent substrate 900 (hereinafter, simply referred to as a "transparent substrate") according to an embodiment of the present invention.

The transparent base body 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 anti-glare treated.

The method of anti-glare treatment is not particularly limited. The anti-glare treatment may be, for example, a frost treatment, an etching treatment, a sandblasting treatment, a lapping treatment, a silica coating treatment or the like. The first surface 902 of the transparent gas may have a surface roughness (arithmetic mean roughness (Ra)) in the range of, for example, 0.05 mu m to 1.0 mu m.

Further, the transparent substrate 900 may have the first surface 902 and / or the second surface 904 chemically strengthened.

The dimensions and shape of the transparent substrate 900 are not particularly limited. For example, the transparent substrate 900 may be square, rectangular, circular, elliptical, or the like.

When the transparent substrate 900 is used as a protective cover of a display device, the thickness of the transparent substrate 900 is preferably small. For example, the thickness of the transparent substrate 900 may be in the range of 0.2 mm to 2.0 mm.

Here, the transparent base body 900 has a characteristic that the value of the diastrophism index R measured using the first method (steps S110 to S130) is 0.4 or more. The transparent base body 900 is provided with a flashing index value G measured as a distance index r = 8 using the above-described second method (including steps S210 to S290, step S265) , And 0.6 or less.

The ruggedness index value R is preferably 0.6 or more, more preferably 0.8 or more.

Further, the glare index value G is preferably 0.5 or less, more preferably 0.4 or less, and further preferably 0.3 or less.

Example

Next, the results of the flicker-resistance evaluation and flashing evaluation performed using various transparent substrates will be described.

(About the evaluation of flammability)

The anti-glare properties of the transparent substrate on which the first surface was anti-glare treated by various methods were evaluated in the following manner.

As the anti-glare treatment, a frost treatment, an etching treatment, a sandblasting treatment, a lapping treatment, or a silica coat treatment was employed. Aluminosilicate glass was used for the transparent substrate.

First, each of the transparent substrates was visually observed from the first surface (i.e., the surface subjected to anti-glare treatment), and the anti-glare properties were evaluated in 12 steps from level 1 to level 12. [ In addition, the observation direction was 20 占 with respect to the thickness direction of the transparent substrate.

Next, an operation as shown in the above-mentioned steps S110 to S130 is performed using a goniophotometer (GC5000L: manufactured by Nippon Denshoku Industries Co., Ltd.), and the divergence index value R of each transparent substrate is calculated from the equation (1) Respectively.

Fig. 8 shows an example of the relationship between the evaluation level (vertical axis) of visually observable scattering property obtained on each transparent substrate and the scattering index value R (horizontal axis).

From FIG. 8, it can be seen that there is a positive correlation between them.

This result shows that the diffusive index value R corresponds to the tendency of the evaluation level of the reflection image diffusibility by the naked eye of the observer and thus the diffusive index value R is used to judge the reflection image diffusibility of the transparent substrate I suggest that you can. In other words, by using the diffusing index value R, it can be said that the reflection image diffusibility of the transparent substrate can be judged objectively and quantitatively.

(About evaluation of flashing)

Next, using various transparent substrates used in the above-mentioned evaluation of the diffusibility, the flashing of these transparent substrates was evaluated by the following method.

First, each transparent substrate is placed directly on a display device (iPad (registered trademark), resolution 264 ppi). At this time, the transparent substrate was placed on the display so that the first surface (i.e., the anti-glare treated surface) of each transparent substrate was on the observer side. The image displayed from the display device was a green monochromatic image, and the dimensions of the image were 19.6 cm x 14.6 cm.

Next, in this state, each of the transparent substrates was visually observed from the first surface side, and the flashing was evaluated in 11 levels from level 0 to level 10. Level 0 indicates that the flashing is hardly observed, and Level 10 indicates that the flashing is very conspicuous. In addition, the level value between these values tends to increase as the numerical value increases.

Next, operations as shown in the above-described steps S210 to S290 (including step S265) are performed using an SMS-1000 apparatus (manufactured by Display-Messtechnik & Systeme) The glare index (G) of the gas was calculated. VRD140 anti-glare treated glass (manufactured by Asahi Glass Co., Ltd.) was used as the reference transparent glaze treated anti-glare substrate.

The above-mentioned iPad (registered trademark) was used for the display device, and the distance d between the solid-state image sensor and the transparent substrate was 540 mm. This distance d corresponds to r = 10.8 when expressed by a distance index r.

Fig. 9 shows an example of the relationship between the flashing index value G (vertical axis) and the level of glare (horizontal axis) obtained by the naked eye, which is obtained in each transparent substrate.

From FIG. 9, it can be seen that there is a positive correlation between the two.

This result shows that the flashing index value G corresponds to the tendency of the judgment result of the glare caused by the naked eye of the observer, and therefore the glare indicator value G can be used to determine the flashing of the transparent gas . In other words, by using the flashing index value G, the flickering of the transparent gas can be judged objectively and quantitatively.

As described above, it was confirmed that the dust-repelling index value R and the flashing index value G can be used as quantitative indices of the scattering property and the flashing of the transparent gas, respectively.

Industrial availability

INDUSTRIAL APPLICABILITY The present invention can be used for evaluating the optical characteristics of a transparent substrate provided on various display devices such as an LCD device, an OLED device, a PDP device, and a tablet-type display device.

The present 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 transparent gas
212 First surface
214 Second surface
300 measuring device
350 light source
362 First Light
364 Reflected light
370 detector
410 first picture
420-1 to 420-9 corresponding area
430 First luminance distribution
900 transparent gas
902 First surface
904 Second surface
q _i luminance distribution component

Claims (10)

As a method for evaluating the optical characteristics of a transparent substrate,
Obtaining a quantified anti-glare index value of the transparent substrate having the first and second surfaces, the anti-glare treatment of the first surface,
A step of acquiring a quantified glare index value of the transparent substrate in a non-sequential manner,
The quantified anti-
(a) irradiating first light from the first surface side of the transparent substrate having the first and second surfaces in a direction of 20 占 with respect to the thickness direction of the transparent substrate; A step of measuring a luminance of regularly reflected light,
(b) changing a light receiving angle of the reflected light reflected by the first surface in a range of -20 to +60 degrees, and measuring a luminance of the entire reflected light reflected by the first surface;
(c) From the following equation (1), the step of calculating the anti-scattering index value R
Flammability Index (R) =
(Luminance of all reflected light-luminance of regularly reflected light of -20 DEG) / (luminance of total reflected light)
Lt; / RTI >
The quantified glare indicator value
(A) placing the transparent substrate on the display device so that the second surface is on the display device side, and
(B) obtaining a first image by photographing the transparent substrate using the solid-state image pickup element in a state in which the display device is turned on, wherein a distance between the solid-state image pickup element and the transparent substrate is d , And the distance index r (= d / f) at the time of photographing when the focal length of the solid-state image sensor is f,
(C) forming a first luminance distribution from the acquired first image,
(D) moving the transparent substrate with respect to the display device by moving the transparent substrate in a direction substantially parallel to the second surface,
(E) repeating the steps (B) and (C) to form a second luminance distribution from the acquired second image,
(F) obtaining a difference luminance distribution (? S) from a difference between the first luminance distribution and the second luminance distribution;
(G) calculating an average luminance distribution (ΔS _ave ) and a variance (σ) from the differential luminance distribution (ΔS) and obtaining an output value (A) from the following expression (2)
Output value (A) = dispersion (?) / Average luminance distribution (? S _ave )
(H) A step of performing the above steps (A) to (G) with a transparent gas subjected to a reference anti-glare treatment to obtain a reference output value Q instead of the output value A, The step includes steps performed before the steps (A) to (G) or in parallel with the steps (A) to (G)
(I) From the following equation (3), the step of obtaining the flashing index value G
(G) = (output value (A)) / (reference output value (Q)) Expression (3)
≪ / RTI > The method according to claim 1,
Before the step of (G), a step of removing a component derived from the display device from the differential luminance distribution (? S) to obtain an effective differential luminance distribution (? S _e )
In the step of the (G), in place of the difference between the luminance distribution (ΔS), wherein the method is effective luminance distribution difference (ΔS _e) is used. 3. The method according to claim 1 or 2,
Wherein the zigzagging index value is obtained using a goniometer. 4. 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-type display device. 5. The method according to any one of claims 1 to 4,
Wherein the display device has a resolution of 132 ppi or more. 6. The method according to any one of claims 1 to 5,
Wherein the transparent gas is composed of soda lime glass or aluminosilicate glass. The method according to claim 6,
Characterized in that at least one of the first and second surfaces is chemically strengthened. 8. The method according to any one of claims 1 to 7,
Wherein the anti-glare treatment is performed by applying at least one treatment method selected from the group consisting of a frost treatment, an etching treatment, a sandblasting treatment, a lapping treatment, and a silica coat treatment to the first surface of the transparent substrate. 1. A transparent substrate having first and second surfaces, the first surface being anti-glare treated,
When evaluated by the method according to any one of claims 1 to 5,
(R) is 0.4 or more,
And the flashing index value (G) is 0.6 or less. 1. A transparent substrate having first and second surfaces, the first surface being anti-glare treated,
When evaluated by the method according to any one of claims 1 to 5,
(R) is 0.4 or more,
Wherein the flashing index value (G) is 0.3 or less.

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