KR20070023809A - Antiglare Film - Google Patents

Abstract

The present invention enables quantitative grasping of the glare intensity generated by surface irregularities. The light from the white light sources 1 and 4 is incident on the surface of the object 3 through the matrix filters 2 and 5 so as to make the object ( 3) The reflected or transmitted light from 3) is photographed by the CCD camera 6, stored as data in the computer 7, and subjected to image processing of the luminance distribution of the stored light to obtain the standard deviation of the dispersion of the luminance distribution. As the flash value of the object, the performance of the object is evaluated according to whether or not the flash value is equal to or less than a predetermined value.

Glare, Anti-glare Film, Luminance Distribution

Description

Anti-glare Film {Antiglare Film}

1 is a view showing a schematic configuration of an evaluation apparatus of the present invention;

2 is a view showing a flow of measurement;

3 shows the contents of an image in the flow of the measurement of FIG. 2;

4 is a diagram for explaining a change in luminance distribution by image processing;

5 is a diagram for explaining the change in luminance when the flash is small and when the flash is large;

6 shows measurement results.

<Description of Symbols for Main Parts of Drawings>

1: White light source for measuring transmitted light 2, 5: Matrix filter

3: anti-glare film (sample) 4: white light source for reflection light measurement

6: CCD camera 7: Computer

The present invention relates to a method and apparatus for quantitatively evaluating glare caused by surface irregularities, and to an anti-glare film having good anti-glare characteristics and a method of manufacturing the same.

In display units such as LCDs, a phenomenon called scintillation occurs, which makes it difficult for an observer to see the display. Flash is a phenomenon in which a small luminance imbalance appears on the screen when the display device is turned on, and when the time is changed, the position of the luminance imbalance seems to shift and change, especially when the front white display or the front green display is displayed. easy. In the display device, it is necessary to evaluate the degree of such a glare, and a 20 ° spherical glossiness measuring method for measuring the intensity of light reflected when a light is incident at an angle of 20 ° with respect to a test piece is used. It is adopted. However, because glare is caused by surface irregularities and the like, accurate evaluation cannot be made by the method of measuring the amount of reflected light. Therefore, the visual evaluation method has been used conventionally for the determination of the good or bad of an anti-glare film for preventing a glare.

However, it was undeniable that individual differences occurred or lacked accuracy in the evaluation of the flash by visual observation. Therefore, in the development of anti-glare films and the like, it is required to be able to quantitatively evaluate the intensity of the flash to grasp the performance thereof.

An object of the present invention is to solve the above problems and to quantitatively evaluate the intensity of flashes changing due to surface irregularities.

Moreover, an object of this invention is to obtain the anti-glare film excellent in the glare prevention characteristic.

In the quantitative evaluation method of the flash of the present invention, light from a white light source is incident on a surface of an object through a matrix filter, photographed reflected light or transmitted light from the object, taken as data, and the luminance of the received light. Image processing of the distribution to obtain the standard deviation of the dispersion of the luminance distribution, wherein the obtained standard deviation value is used as the flash value of the surface of the object.

Moreover, the evaluation method of this invention is characterized by the said object being an anti-glare film.

Moreover, the evaluation method of this invention is characterized by evaluating the performance of an object according to whether a flash value is below a predetermined value.

The evaluation method of the present invention is characterized in that the predetermined value of the flash value is 15 when measured at an average luminance of 145 cd / m 2 of the stored image.

The apparatus for quantitatively evaluating the glare of the present invention comprises at least a white light source, a matrix filter, a photographing apparatus, and a computer, wherein light from the white light source is incident on the surface of the object through the matrix filter to reflect reflected light or transmitted light from the object into the photographing apparatus. It is characterized by photographing and storing it as data, processing the data with a computer to obtain the standard deviation of the dispersion of the luminance distribution, and using the calculated standard deviation value as the flash value of the object surface.

The evaluation apparatus of the present invention is characterized in that the photographing apparatus is a CCD camera.

Moreover, the evaluation apparatus of this invention is characterized by the said object being an anti-glare film.

Moreover, the evaluation apparatus of this invention is characterized by evaluating the performance of a target object whether a flash value is below a predetermined value.

The evaluation apparatus of the present invention is characterized in that the predetermined value of the flash value is 15 when measured at an average luminance of 145 cd / m 2 of the stored image.

The anti-glare film of the present invention is characterized by having a glare value greater than 0 and less than or equal to 15 when measured at an average luminance of 145 cd / m 2 of a stored image.

In the anti-glare film of the present invention, in the anti-glare film having an anti-glare layer formed on at least one surface of the base, light from a white light source is incident on the anti-glare film surface through a matrix filter to reflect light from the anti-glare film. Alternatively, the transmitted light is photographed by a photographing apparatus and stored as data, and image processing of the luminance distribution of the stored light is performed by a computer to obtain a standard deviation of dispersion of the luminance distribution. The anti-glare layer is formed so as to be stationary or less.

The manufacturing method of the present invention is characterized in that the photographing apparatus is a CCD camera.

The manufacturing method of the present invention is characterized in that a predetermined value of the flash value is 15 when measured at an average luminance of 145 cd / m 2 of the stored image.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

1 is a view showing a schematic configuration of an evaluation apparatus of the present invention.

The matrix filter 2 is disposed so as to face the processing surface toward the light source side with a gap slightly above the white light source 1 for transmission light measurement, and the antiglare film (AG film) 3 is subjected to antiglare treatment on the matrix filter 2. The processed surface is brought into close contact with the photographing side. Similarly, the matrix filter 5 is arranged so as to face the processed surface toward the light source with a gap slightly above the white light source 4 for measuring the reflected light facing the processed surface of the anti-glare film 3. As the processed surface of the anti-glare film 3, a material mainly containing fine particles is used. The matrix filters 2 and 5 are, for example, zigzag gratings having a length of 85 mm, a width of 65 mm, a thickness of 1 mm, and a pitch of 140 µm x 170 µm. It is a color filter. Although a pseudo color filter is used here, you may use a colored color filter as needed. Moreover, it is preferable to use a white flat light source as a light source.

To enable the evaluation of the processed surface of the anti-glare film 3 illuminated through the matrix filter "2" or "5" at the white light source "1" or "4" in a state close to visual. In order to take a picture with a CCD camera (6). The distance between the CCD camera 6 and the sample (anti-glare film) is, for example, about 250 mm. The focus of the CCD camera 6 is set to such a degree that the matrix of the matrix filters 2 and 5 is clear, and the aperture is adjusted to an appropriate place. In addition, the measurement by the configuration of the white light source, the matrix filter, the sample, and the CCD camera is to assume the configuration of the liquid crystal display and to reproduce it pseudo.

The data obtained by imaging is stored in the computer 7. At this time, in order to prevent the occurrence of a break in the calculation of the image processing, the stored data of 8 bit gray scale is converted into 16 bit gray scale. The stored data is subjected to image processing to obtain a value suitable for digitization. Image processing consists of low-pass filtering, shading correction, and contrast emphasis. The emphasis of contrast is set to contrast 93, gamma 30 and brightness 48, for example. If the brightness is too high or too low, adjust the iris of the CCD and start the measurement again. In this case, the average luminance is preferably about 145 cd / m 2. The numerical value of the intensity of the glare is obtained by calculating the dispersion of the luminance as a standard deviation and indicating it as the standard deviation value. The performance of the sample is evaluated by comparing the obtained flash value with a predetermined value. In addition, since the exact same state is not always reproduced due to changes in the measurement environment (contamination of the matrix filter, shaking of the light source, etc.), a standard sample is provided for correction except for continuous measurement. It is desirable to.

2 is a view for explaining the flow of the measurement by the apparatus of FIG.

First, a film to be measured is placed on a matrix filter, the film surface is photographed by a CCD camera, and then image data obtained by photographing is stored in a computer for image processing.

3 shows the contents of an image to be processed.

In the image processing, an area for image processing is selected for the image as it is stored. This is because only the part to which the anti-glare film adheres is made into an object of image processing, and FIG. 3 (a) is a raw image thereof. In this image, the luminance change caused by the matrix of the matrix filter is clearly shown.

FIG. 3B shows an image in which the high frequency is removed by filtering the live image, and the luminance change caused by the matrix of the matrix filter is not shown. This filtering is a process that is performed to make the conditions as seen by the eye in the sense that the matrix of the matrix filter cannot be recognized when the glare is evaluated by the eye. The filtering is performed by applying a low pass filter to the extent that the matrix is unknown. Specifically, the low pass filter of the used software is added to the kernel 7 × 7 and 100% three times.

Then, the luminance is flattened. FIG. 3 (c) is a luminance correction applied to the image of FIG. 3 (b), and shading correction is performed to correct the luminance distribution generated due to the surface distribution of the luminance of the light source itself. The maximum point is 10 pixels (pixel). ).

3 (d) shows contrast emphasis. The emphasis on contrast is not essential after quantification but is intended to make the luminance distribution easier to see after evaluating the glare.

In the image processed as above, the standard deviation value of luminance is obtained at the portion where there is no change in luminance due to damage to the matrix filter or the like. At this time, the area of the image processing is moved so that the average value of the luminance becomes almost the same value for each sample. As a result, there is a luminance distribution in the light source and the average value changes according to the area. If it is inappropriate to move anywhere, change the aperture of the CCD camera.

Fig. 4 is a diagram for explaining the change in luminance distribution by image processing, showing the image before and after image processing and the luminance distribution. In this example, the number of pixels is 160 × 120 and the actual size is 10 mm × 7.5 mm.

Fig. 4A shows the stored live image, and Fig. 4B shows the luminance distribution at that time. As can be seen from FIG. 4 (b), the luminance distribution is changed very small under the influence of the matrix of the matrix filter, and an image as shown in FIG. 4 (c) is obtained by performing the above-described image processing. The luminance distribution at the time is as shown in Fig. 4D. The magnitude A of the change at this time is the data for calculating the standard deviation.

5 is a view for explaining the change in luminance when the flash is small and when the flash is large. FIG. 5A shows a small flash image, and the luminance distribution at that time is as shown in FIG. 5B. It can be seen from FIG. 5B that the change B in luminance is extremely small. FIG. 5C shows a large flash image, and the luminance distribution at that time is shown in FIG. 5D, and it can be seen that the change C of luminance is large.

The magnitudes B and C of the change in luminance are standard deviations, and this value is referred to as the numerical value of the intensity of the flash. The larger the value, the stronger the flash. Absolute values change due to differences in measuring devices (light sources, matrix filters, CCD cameras), image processing software or fine image processing methods, but relative relationships are maintained. By carrying out the measurements in the same manner, a reproducible numerical value can be obtained.

In addition, the instrument used for the measurement in a present Example is as follows.

Optical device: Mapping type evaluation device type MJ-RTS (Mizojiri

                  Optical Co., Ltd.)

CCD Receiver: CCD Camera (KP-M1)

                  C mount adapter (Nikon)

                  Close-up ring (PK-11A; Nikon)

                  Camera lens (50mm, F1.4s NIKKOR)

Light source: LIGHTBOX 45 (HAKUBA)

Matrix Filter: Pitch: 140㎛ × 170㎛, Camera Thickness: 1mm

Image Processing Software: Image-Pro Plus 3.0 for Windows 95

                      (Media Cybemetics)

Fig. 6 shows measurement results at an average luminance of 145 cd / m 2 of the stored image, and shows a glossiness measuring device (gloss 20 °), a sensory test, and a flash value of the present invention, respectively.

In Figure 6,

Sample 1: containing silica particles having a particle diameter of 1 to 2 µm (Ra = 0.256 Sm = 40.1)

Sample 2 containing silica particles having a particle diameter of 1 to 2 μm (Ra = 0.186 Sm = 30.2)

Sample 3: containing silica particles having a particle diameter of 1 to 2 μm (Ra = 0.307 Sm = 30.5)

Sample 4: containing silica particles having a particle diameter of 1 to 2 µm (Ra = 0.385 Sm = 29.7)

Sample 5: Particle Free (Emboss) (Ra = 0.102 Sm = 31.1)

Sample 6: containing silica particles having a particle diameter of 3 μm (Ra = 0.205 Sm = 25.9)

Sample 7: Silica Particles with a Particle Size of 3 μm (Ra = 0.264 Sm = 23.7)

Sample 8: Silica Particles Contained (Ra = 0.323 Sm = 36.2)

Transparent film (base film) without TAC antiglare treatment

Ra is one of the measured values showing the surface roughness of the JIS standard (center line average roughness), the unit is a numerical value expressed in 占 퐉, and Sm is a numerical value in which the interval from the valley of the surface irregularities to the valley is expressed in 占 퐉.

How to measure

[Gloss (20 °)]

According to JIS-S-Z-8741, the film back surface was attached to the pressure plate (black without gloss) with double-sided tape, and measured using GM-26D manufactured by Murakami Color Research Institute.

[Sensory Test]

The matrix filter is placed on the white surface light source (inspection viewer) with the processing surface facing down, and the anti-glare film is placed on the processing surface facing upward, and the glare is observed while pressing the end of the film by hand.

◎ --- No glare

○ --- There is a slight flash, but not enough to feel it.

△ --- Glare is felt.

× --- Flash is strong.

In the case of the gross | gloss (20 degrees), it is said that the flash is large, but it may be suitable for the sensory test from the result of FIG. 6, and may not be suitable. For example, Sample 1, Sample 3, Sample 4, Sample 6, and Sample 7 relatively match, but not Sample 2, Sample 5, Sample 8, and base film. On the other hand, the glare value obtained in the present invention is consistent with the sensory test over the exhibition fee. In addition, when measured at an average luminance of 145 cd / m 2 of the stored image, the glare characteristics of the anti-glare film are good and bad, depending on whether the glare value is 15 or less.

As described above, according to the present invention, it is possible to quantify the glare almost in line with the sensory test by measuring the luminance distribution, processing the image, and setting the standard deviation as the glare value, which is very effective in the development of anti-glare films and the like.

Claims (1)

The glare value is greater than 0 and less than or equal to 15 when measured at an average luminance of 145 cd / m 2 of the stored image.

Images