TWI792165B - Optical components and display devices - Google Patents

Abstract

According to one aspect of the present invention, a method for evaluating blurred characters is provided, which is a method for evaluating blurred characters of a display device 20, and is characterized in that: a plurality of lines 20B are displayed on the display surface 20A of the display device 20, and the lines 20B In the state of two or more kinds of stripe patterns 20C to 20E having different line widths LW, the light emitted from the display device 20 is photographed, and the brightness change in the direction crossing each stripe pattern 20C to 20E is obtained from the captured light, And the contrast of each of the stripe patterns 20C to 20E was obtained from the above-mentioned change in luminance, and the blurring of characters was evaluated.

Description

Optical components and display devices

The invention relates to a character blur evaluation method, an optical component and a display device. [Reference to Related Applications]

This application enjoys the benefit of priority of Japanese Patent Application No. 2016-150754 (filing date: July 29, 2016) and Japanese Patent Application No. 2016-154204 (application date: August 5, 2016), which are the previous Japanese applications. The entire disclosure content of etc. is made a part of this specification by citing.

In the past, display devices such as TVs, smart phones, tablet terminals, and car navigation devices were usually equipped with anti-glare films with uneven surfaces or anti-reflection layers in order to suppress the reflection of the observer and the background of the observer. Anti-reflective film.

In a display device equipped with an anti-glare film, image light may be scattered due to the concave-convex surface of the anti-glare film, thereby causing glare. In particular, glare is likely to be generated along with the high-definition display devices in recent years. Based on such circumstances, studies have been made on disposing a light-diffusing layer or the like in order to suppress glare (for example, refer to Japanese Patent Application Laid-Open No. 2014-126598 ).

[Problem to be Solved by the Invention]

However, in a high-definition display device, if glare is suppressed by the light-diffusing layer, the characters displayed on the display device may become blurred, and so-called blurred characters may occur.

In addition, in recent years, display devices have also been used in vehicle applications. In this case, from the viewpoint of ensuring safety, it is necessary not only to grasp image information instantaneously and accurately while driving, but also to be able to instantaneously Accurately grasp text information. For example, when the display device is used as a car navigation device, the map information displayed on the display device includes not only graphic information such as roads, but also text information, so it is necessary to grasp the text information instantaneously and accurately. Therefore, for a display device used in a vehicle, it is required to have a sharpness which is extremely high compared with the sharpness of conventional characters, and which can grasp character information instantaneously and accurately even while driving.

However, at present, the method for evaluating blurred characters has not been established, so even if it is necessary to grasp the level of clarity of character information instantaneously and accurately during driving, it is impossible to grasp the degree of clarity of characters obtained, that is, What degree of text blurring occurred. Furthermore, since there are various types of characters with different thicknesses, even if the blurring of one type of character is evaluated, the evaluation result cannot be applied to a character having a different thickness than the character for which the blurring of characters was evaluated.

On the other hand, the current situation is that although it is necessary to suppress both the glare and the blurred characters, the glare and the blurred characters are in a trade-off relationship, and it is impossible to suppress both the glare and the blurred characters.

Furthermore, many of the display devices used for in-vehicle use have a front panel disposed on the viewer's side rather than the display element from the standpoint of durability improvement and design improvement. In this case, from the viewpoint of ensuring safety, it is necessary to grasp not only image information but also text information instantaneously and accurately while driving. For example, when the display device is used as a car navigation device, as described above, it is necessary to grasp text information instantaneously and accurately. Furthermore, since there are various styles of characters with different thicknesses, even if blurring of characters is suppressed for characters of a certain thickness, blurring of characters may not necessarily be suppressed for characters of different thicknesses.

Therefore, in order to grasp the text information instantaneously and accurately in the display device used in the vehicle, even in the optical member equipped with the front panel, anti-glare film and light diffusion film, it is necessary to accurately reproduce The color of each pixel suppresses blurring of text regardless of the thickness (size) of the text.

The present invention is to solve the above-mentioned problems. That is, the object is to provide a character blurring evaluation method of a display device and an optical member that can evaluate the degree of blurring of characters in two or more types of characters having different thicknesses. Another object is to provide an optical member and a display device capable of suppressing glare and suppressing blurring of characters regardless of the thickness of the characters. [Technical means to solve the problem]

According to an aspect of the present invention, there is provided a method for evaluating blurred characters, which is a method for evaluating blurred characters of a display device, characterized in that: the display surface of the display device is composed of a plurality of lines and the line widths of the lines are different In the state of two or more stripe patterns, the light emitted from the above-mentioned display device is photographed, the brightness change in the direction transverse to each stripe pattern is obtained from the above-mentioned light captured, and each of the above-mentioned The contrast of the stripe pattern, the evaluation text is blurred.

According to another aspect of the present invention, there is provided a method for evaluating blurred characters, which is a method for evaluating blurred characters of optical components, characterized in that an optical component is arranged on the display surface of the display device, and a In the state of two or more kinds of fringe patterns composed of a plurality of lines and the line widths of the above-mentioned lines are different, the light emitted from the above-mentioned display device and transmitted through the above-mentioned optical member is photographed, and the cross-cutting of each of the above-mentioned fringes is obtained from the photographed light Brightness changes in the direction of the pattern, and the contrast of each of the above-mentioned stripe patterns was obtained from the above-mentioned brightness changes, and the blurring of characters was evaluated.

In at least any one of the character blur evaluation method of the display device and the character blur evaluation method of the optical member, the contrast of each of the stripe patterns can be obtained from the following formula (1). C=(M-m)/(M+m)...(1) (In the formula (1), C is the contrast, M is the maximum value of the brightness in the stripe pattern, and m is the minimum value of the brightness in the stripe pattern)

In at least any one of the method for evaluating character blurring of the above-mentioned display device and the method for evaluating character blurring of the above-mentioned optical member, the line width may be 1 pixel or more and 4 pixels or less.

In at least any one of the method for evaluating character blurring of the above-mentioned display device and the method for evaluating character blurring of the above-mentioned optical member, the imaging of the light may be performed on the display surface where three or more kinds of the above-mentioned fringe patterns with different line widths are displayed. status.

In at least any one of the character blur evaluation method of the display device and the character blur evaluation method of the optical member, the imaging of the light may be performed with a CCD camera.

In at least any one of the character blur evaluation method of the said display device and the character blur evaluation method of the said optical member, the said optical member may be provided with a light-diffusion film.

According to another aspect of the present invention, there is provided an optical member disposed on the viewer's side of a display panel having a display element, characterized by comprising: an anti-glare film having an anti-glare film constituting the viewer's side of the above-mentioned optical member. The concave-convex surface of the surface; the intermediate member arranged on the side of the anti-glare film opposite to the concave-convex surface; and the light diffusion film arranged on the side of the display panel closer to the intermediate member.

In the above optical member, the intermediate member may include a front panel or a touch panel.

In the above-mentioned optical member, the thickness of the above-mentioned intermediate member may be not less than 0.1 mm and not more than 5 mm.

According to another aspect of the present invention, there is provided a display device, which is characterized by comprising: a display panel having a display element; an anti-glare film disposed on the viewer side of the display panel and having a viewer constituting the display device. The concave-convex surface of the surface on the side; the intermediate member, which is arranged between the above-mentioned display panel and the above-mentioned anti-glare film; and the light diffusion film, which is arranged between the above-mentioned display panel and the above-mentioned anti-glare film, and is arranged in the middle The member is closer to the above-mentioned display panel side.

In the said display device, the distance between the said display element and the said light-diffusion film may be 1 mm or less.

In the above-mentioned display device, the above-mentioned display device may be a vehicle-mounted display device. [Effect of Invention]

According to the character blur evaluation method of a display device of one aspect of the present invention and the character blur evaluation method of an optical member of another aspect of the present invention, the degree of blur of characters in two or more types of characters with different thicknesses can be evaluated respectively. According to the optical member of another aspect and the display device of another aspect of the present invention, glare can be suppressed, and blurring of characters can be suppressed regardless of the thickness of the characters.

[First Embodiment] Hereinafter, the character blur evaluation method of the display device according to the first embodiment of the present invention will be described with reference to the drawings. The term "character" in this manual refers to the narrow meaning of characters including hiragana, katakana, kanji and letters used to express sentences or words, and also includes concepts such as numbers, symbols and graphics. In addition, in this specification, a "film" is used in the meaning which also includes what can also be called a sheet. As a specific example, "anti-glare film" also includes members called "anti-glare sheet". FIG. 1 is a diagram for explaining a method for evaluating blurred characters of a display device according to an embodiment. FIG. 2 is a diagram schematically showing a stripe pattern displayed on the display surface of the display device shown in FIG. 1 , and FIG. 3 is a part of stripes. Enlarged view of the pattern.

＜＜＜Text blur evaluation method for display device＞＞＞ The method for evaluating blurred characters of a display device described in this embodiment is a method for evaluating the degree of blurred characters of a display device itself. When evaluating the character blurring of a display device, first, as shown in FIG. 1 , a character blurring evaluation device 10 and a display device 20 to be evaluated are prepared.

＜＜Text Blurring Evaluation Device＞＞ The character blur evaluation device 10 includes: an imaging device 11 ; and a processing device 12 electrically connected to the imaging device 11 .

＜Camera equipment＞ The imaging device 11 is used to photograph the light emitted from the display surface 20A of the display device 20 , and the imaging device 11 is arranged on the display surface 20A of the display device 20 . As the imaging device 11 , for example, a CCD camera (Charge-Coupled Device camera) can be used.

The distance between the imaging device 11 and the display surface 20A varies depending on the resolution of the imaging device, for example, it is preferably set to 50 mm or more and 500 mm or less. When shooting, it is preferable to focus the imaging device 11 so that the fringe pattern described below becomes clearest, and to align the aperture with an appropriate position.

＜Processing device＞ The processing device 12 captures the light captured by the camera device 11 in the form of an image. For the captured image, image processing may not be performed, but in the case of a lot of noise, for example, it is better to perform image processing such as low-pass filter processing to further reduce the noise. However, since the contrast may change depending on the conditions of image processing, when image processing is performed, it is preferable to perform the same processing among samples to be compared.

＜<Display device＞＞ The display device 20 includes: a display element 21; and a display surface 20A that is located on the viewer's side with respect to the display element 21 and that can display characters or stripe patterns 20C to 20E described below. It does not specifically limit as the display element 21, A liquid crystal display element or an organic electroluminescent element is mentioned. The liquid crystal display element is made by disposing a liquid crystal layer, an alignment film, an electrode layer, a color filter, etc. between two glass substrates. The display device 20 may include a polarizing plate, an optical film, and/or a touch panel, etc., on the viewer side of the display element 21 .

The luminance of white display on the display surface 20A of the display device 20 is preferably 400 cd/m ² or higher. Also, the size of the display device 20 may be, for example, not less than 1 inch and not more than 500 inches.

As shown in FIG. 2 , the display device 20 is capable of displaying two or more, preferably three or more stripe patterns 20C to 20E composed of a plurality of lines 20B and having different line widths LW (refer to FIG. 3 ) of the lines 20B. on the display surface 20A. The display device 20 shown in FIG. 2 is capable of displaying three types of stripe patterns 20C to 20E having different line widths LW. When the display device is a tablet terminal, for example, on the display surface of a personal computer (PC), a stripe pattern can be created in such a way that the desired stripe pattern is displayed on the display device as a tablet terminal, and the created stripe pattern can be transmitted. To the display device as a tablet terminal, and display the stripe pattern on the display surface of the display device through the application software.

On the display surface 20A of the display device 20, from the viewpoint of making the stripe patterns 20C to 20E close to actual characters, it is preferable to have stripes having the same or similar number of pixels as the line width LW of the lines constituting the characters. Patterns 20C to 20E are displayed respectively. Usually, the width of characters used in a display device is about 1 to 4 pixels in many cases, so the line width LW of the lines 20B constituting the stripe patterns 20C to 20E is preferably 1 to 4 pixels. Specifically, it is preferable to display a stripe pattern with a line width of 1 pixel, a stripe pattern with a line width of 2 pixels, and a stripe pattern with a line width of 4 pixels on the display surface 20A of the display device 20 .

The number of lines 20B constituting the stripe patterns 20C to 20E is not particularly limited, but is preferably 5 or more from the viewpoint of measurement accuracy. Also, the number of lines 20B constituting the stripe patterns 20C to 20E may vary for each of the stripe patterns 20C to 20E, but in terms of the number of stripe patterns having a smaller line width, it is preferable that each The stripe patterns 20C to 20E have no difference in area, so the areas of the stripe patterns 20C to 20E are preferably substantially constant.

The length LL (see FIG. 3 ) of the lines 20B of the stripe patterns 20C to 20E is not particularly limited, but is preferably not less than 0.5 cm and not more than 3 cm in terms of measurement accuracy and ease of measurement.

The interval LD between the lines 20B of the stripe patterns 20C-20E (refer to FIG. 3 ) is not particularly limited, but it is preferably the distance between the lines 20B constituting the stripe patterns 20C-20E from the viewpoint of ease of universal application of various characters. The line width LW is the same. For example, when the line width of the lines of the stripe pattern is 1 pixel, the interval between the lines of the stripe pattern is preferably 1 pixel, and when the line width of the lines of the stripe pattern is 2 pixels, the distance between the lines of the stripe pattern The interval between lines is preferably 2 pixels, and when the line width of the lines of the stripe pattern is 4 pixels, the interval between lines of the stripe pattern is preferably 4 pixels.

The color of the stripe patterns 20C to 20E is not particularly limited, and it is conceivable that the color of the background of the stripe patterns 20C to 20E is different from the viewpoint of displaying the stripe patterns 20C to 20E. For example, when the stripe pattern is black, the background of the stripe pattern can be white, and when the stripe pattern is white, the background of the stripe pattern can be black.

The application of the display device 20 is not particularly limited, for example, it may be used in vehicles such as television, personal computer, smart phone, tablet terminal, and car navigation device. In particular, in a display device having a large contrast value described below, the degree of blurring of characters is small, so that a level of sharpness at which character information can be grasped instantaneously and accurately even while driving can be obtained. Therefore, a display device with a large contrast ratio is suitable for in-vehicle use.

After the character blur evaluation device 10 and the display device 20 are prepared, the display device 20 is arranged so that the display device 20 becomes substantially horizontal, and the imaging device 11 is arranged in the vertical direction of the display device 20 . Then, in a state where two or more stripe patterns 20C to 20E are displayed on the display surface 20A of the display device 20, preferably in a dark room, first, place the stripe pattern 20C on the image captured by the imaging device 11. The position of the display device 20 is aligned approximately in the center, and the light emitted from the display device 20 is photographed by the camera device 11 . Next, the display device 20 is moved approximately horizontally, and the position of the display device 20 is aligned so that the stripe pattern 20D is positioned at approximately the center of the image captured by the imaging device 11. Similarly, the light emitted from the display device 20 is captured. . Furthermore, the display device 20 is moved approximately horizontally, and the position of the display device 20 is aligned so that the stripe pattern 20E is positioned at approximately the center of the image captured by the imaging device 11. Similarly, the light emitted from the display device 20 is captured. . In addition, this shooting is performed in the state which made the display device 20 stand still. Then, by the processing device 12, the brightness change in the direction crossing each stripe pattern 20C-20E is obtained from the captured light, and the contrast of each stripe pattern 20C-20E is obtained from the brightness change, and the character blur is evaluated. The "direction crossing the stripe pattern" in this specification means the direction crossing the lines constituting the stripe pattern, specifically, for example, along the display surface 20A shown by the arrow in FIG. The direction perpendicular to each line 20B of 20E.

The contrast can be obtained by the following formula (1). The reason for determining the contrast ratio by the following formula (1) is that the numerator represents the magnitude of the brightness change, and the denominator represents the magnitude of the overall brightness, so the degree of blurring of characters can be evaluated regardless of the magnitude of the overall brightness. Furthermore, the contrast obtained by the following formula (1) means that the larger the value of the contrast, the smaller the degree of blurring of characters. C=(M-m)/(M+m)...(1) In the formula (1), C is the contrast, M is the maximum value (maximum brightness) of the brightness in the stripe pattern, and m is the minimum value of the brightness (minimum brightness) in the stripe pattern.

According to the present embodiment, since two or more types of stripe patterns 20C to 20E having different line widths are used, and the contrast ratio is obtained for each of the stripe patterns 20C to 20E, it is possible to separate the two or more types of stripe patterns having different thicknesses in the display device 20 . Evaluate the degree of ambiguity of the text in the text. That is, the lines 20B constituting the stripe patterns 20C to 20E can be said to reproduce the lines constituting the characters. Therefore, by using two or more stripe patterns 20C to 20E having different line widths LW, it is possible to carry out two or more characters having different thicknesses. evaluate. Also, the contrast obtained using the stripe patterns 20C to 20E represents the clarity of the stripe patterns 20C to 20E, respectively, so the contrast obtained using the stripe patterns 20C to 20E is equivalent to representing the clarity of characters, that is, the degree of blurring of characters. Thereby, by using two or more types of stripe patterns 20C to 20E having different line widths LW and obtaining the contrast for each of the stripe patterns 20C to 20E, it is possible to separate the two or more types of stripe patterns having different thicknesses in the display device 20 . The degree of ambiguity of the text in the text is evaluated.

When there are two or more display devices having the same or similar pixel densities, it is possible to evaluate which one is obtained by obtaining the contrast for each stripe pattern using the above-mentioned method and comparing the contrast for each of the same stripe patterns. The text of the display device is blurred less or more.

[Second Embodiment] Hereinafter, the character blur evaluation method of the optical member and the optical member according to the second embodiment of the present invention will be described with reference to the drawings. Fig. 4 is a diagram for explaining a method of evaluating blurring of characters in the optical member of the present embodiment.

＜<<Appraisal Method for Character Blurring of Optical Components>>> The character blur evaluation method of the optical member described in this embodiment is a method of evaluating to what extent the character blur occurs due to the optical member. When evaluating the character blurring of the optical member, first, as shown in FIG. Member 40.

＜＜Text Blurring Evaluation Device＞＞ The character blur evaluation device 30 includes: a display device 20 ; an imaging device 11 disposed above the display surface 20A of the display device 20 ; and a processing device 12 electrically connected to the imaging device 11 . The display device 20, the imaging device 11, and the processing device 12 are the same as the display device 20, the imaging device 11, and the processing device 12 described in the first embodiment, and therefore description thereof will be omitted. In addition, in the first embodiment, the display device 20 was used for the evaluation of the display device 20 itself, and in this embodiment, the display device 20 was used for the evaluation of the optical member 40 .

＜＜Optical components＞＞ The optical member means a light-transmitting member used for a display device having certain functions. It does not specifically limit as an optical member, For example, optical films, such as an antiglare film, an antireflection film, a hard coat film, and a light-diffusion film, a front panel, or the member which combined these, etc. are mentioned.

The size of the optical member is not particularly limited, for example, it is appropriately determined according to the size of the display surface of image display devices such as smart phones, tablet terminals, personal computers (PCs), wearable terminals, digital signage, and televisions. Specifically, the size of the optical member may be, for example, not less than 1 inch and not more than 500 inches.

The optical member 40 is not particularly limited, but it is preferable to include an anti-glare film 41 having a surface constituting the viewer's side of the optical member 40 from the viewpoint of suppressing glare and suppressing text blurring at an extremely high level. The concave-convex surface 41A of 40A; the intermediate member 42, which is arranged on the surface 41B side of the anti-glare film 41 opposite to the concave-convex surface 41A; and the light diffusion film 43, which is arranged on the display element 21 closer to the intermediate member 42. side.

＜Anti-glare film＞ The anti-glare film 41 includes, for example, a translucent base material 44 and an anti-glare layer 45 disposed on one side of the translucent base material 44 and having a concave-convex surface 45A serving as a concave-convex surface 41A.

The translucent substrate 44 is not particularly limited as long as it has translucency, and examples thereof include cellulose acylate substrates, cycloolefin polymer substrates, polycarbonate substrates, and acrylic polymer substrates. substrate, polyester substrate, or glass substrate.

The thickness of the light-transmitting base material 44 is not particularly limited, but may be 5 μm or more and 1000 μm or less. The thickness of the translucent substrate 44 means the average value obtained by measuring the thickness of 10 points of the translucent substrate 44 using a thickness measuring device (product name "Digimatic Indicator IDF-130", manufactured by Mitutoyo Corporation). The lower limit of the thickness of the translucent base material 44 is preferably 15 μm or more, more preferably 25 μm or more, from the viewpoint of handleability and the like. The upper limit of the thickness of the translucent base material 44 is preferably 80 μm or less from the viewpoint of thinning.

The antiglare layer 45 is a layer exhibiting antiglare properties. The anti-glare layer 45 may also exhibit anti-glare properties and other functions. Specifically, the anti-glare layer 45 may be a layer that exhibits anti-glare properties, and also functions such as hard coat properties, anti-reflection properties, antistatic properties, or anti-fouling properties.

The thickness of the antiglare layer 45 is not particularly limited, and may be 1 μm or more and 20 μm or less. The thickness of the anti-glare layer 45 is a value measured from images of a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) using image processing software. Here, the surface of the anti-glare layer is concave-convex, so the thickness varies depending on the location, but the above-mentioned "thickness of the anti-glare layer" means the average value obtained by measuring the thickness of 10 points of the anti-glare layer.

Examples of methods for forming the concave-convex surface 45A of the antiglare layer 45 include: (A) a method of forming the concave-convex surface using a composition for an antiglare layer containing a polymerizable compound that becomes a binder resin after hardening and particles; (B) ) A method of forming a concave-convex surface by a transfer method using a metal mold, (C) A method of forming a concave-convex surface by roughening the surface of the antiglare layer by sandblasting, or (D) By using an embossing roller A method of providing unevenness to the surface of the anti-glare layer to form an uneven surface, etc. Among them, the method of (A) above is preferable in terms of ease of production. When the anti-glare layer is formed by the method of (A) above, the anti-glare layer contains a binder resin and particles.

＜Intermediate component＞ The intermediate member 42 is a member disposed between the antiglare film 41 and the light diffusion film 43 , and examples thereof include a front panel, a touch panel, an air layer (air gap), a bonding resin layer, or a combination thereof. The intermediate member 42 shown in FIG. 4 is a front panel. By making the intermediate member 42 a front panel, durability and/or design can be improved.

The thickness of the intermediate member 42 is preferably not less than 0.1 mm and not more than 5 mm. If the thickness of the intermediate member 42 is less than 0.1 mm, the durability of the optical member may not be ensured when the intermediate member 42 is a front panel, and if it exceeds 5 mm, the visibility may deteriorate. The thickness of the intermediate member 42 is obtained by taking a cross-section of the intermediate member 42 using a scanning electron microscope (SEM), measuring the thickness of 10 points of the intermediate member in the image of the cross-section, and setting it as the average value. The lower limit of the thickness of the intermediate member 42 is more preferably 0.5 mm or more, and the upper limit is more preferably 3 mm or less.

When the intermediate member 42 is a front panel, glass, polymethyl methacrylate, polycarbonate, polyimide, etc. are mentioned as a material which comprises a front panel. Among them, glass is preferable from the viewpoint of environmental resistance.

＜Light diffusion film＞ The light diffusion film 43 is used to diffuse incident light. It does not specifically limit as the light-diffusion film 43, For example, the film containing light-diffusion particle|grains, or the film containing a convex structure may be sufficient.

The light-diffusing film 43 shown in FIG. 4 includes, for example, a translucent substrate 46 and light-diffusing particles 47 dispersed in the translucent substrate 46, but is not limited to this structure, and may have a translucent substrate. material, and a light-diffusing layer provided on one side of a light-transmitting substrate and comprising a binder resin and light-diffusing particles dispersed in the binder resin. The light-diffusing film 43 can be obtained by extrusion in the state which added the light-diffusion particle 47 to the resin which comprises the translucent base material 46. Also, the light-diffusing film provided with the light-diffusing layer can be obtained by applying a composition for the light-diffusing layer containing a polymerizable compound that becomes a binder resin after curing and light-diffusing particles on a light-transmitting base material, and curing the composition. And get.

The thickness of the light diffusion film 43 is preferably not less than 20 μm and not more than 300 μm. When the thickness of the light-diffusion film 43 is less than 20 micrometers, light-diffusion property may become inadequate, and when it exceeds 300 micrometers, handleability may deteriorate. The thickness of the light-diffusing film 43 is a cross-section of the light-diffusing film 43 taken with a scanning electron microscope (SEM), and the thicknesses of 10 parts of the light-diffusing film 43 are measured in the image of the cross-section, and set as the 10 parts The average value of the thickness. The lower limit of the thickness of the light-diffusing film 43 is more preferably 50 μm or more, and the upper limit is more preferably 200 μm or less.

(translucent substrate) It does not specifically limit as the translucent base material 46, For example, the thing similar to the translucent base material 44 can be used.

(light diffusing particles) The light-diffusing particles 47 are particles for diffusing light incident on the light-diffusing film 43 . The average particle diameter of the light-diffusing particle 47 is preferably, for example, not less than 1 μm and not more than 30 μm. When the average particle diameter of the light-diffusion particle|grains 47 is less than 1 micrometer, sufficient light-diffusion property may not be acquired, and when it exceeds 30 micrometers, light-diffusion property may become uneven. The average particle diameter of the light-diffusing particles can be obtained as an average value of the diameters of 20 particles measured through observation with an optical microscope or observation with a scanning electron microscope. The lower limit of the average particle diameter of the light-diffusing particle 47 is more preferably 3 μm or more, and the upper limit is more preferably 20 μm or less.

The absolute value of the difference in refractive index between the translucent substrate 46 and the light-diffusing particles 47 is preferably from 0.01 to 0.3. When it is less than 0.01, the light diffusivity in a light-diffusion film becomes insufficient, and when it exceeds 0.3, the transmittance of a light-diffusion film may fall. Regarding the refractive index of the translucent base material 46 and the refractive index of the light-diffusion particle 47, either one may be larger. Here, as a method for measuring the refractive index of the light-diffusing particles included in front of the light-diffusing film, for example, Becke's method, minimum deflection angle method, deflection angle analysis, mode-line method, Measured by ellipsometry, etc. As a method of measuring the refractive index of the light-transmitting substrate and light-diffusing particles in the light-diffusing film, for example, fragments of the light-diffusing particles taken out in some form from the light-diffusing film or fragments of the light-transmitting substrate can be The winner uses the Baker method. In addition, phase shift laser interference microscope (phase shift laser interference microscope manufactured by FK Optical Laboratory or two-beam interference microscope manufactured by Mizojiri Optical Industry, etc.) can also be used to measure the light-transmitting substrate and light diffusion. The refractive index difference of the particles. The lower limit of the absolute value of the difference in refractive index between the light-transmitting substrate 46 and the light-diffusing particles 47 is more preferably 0.05 or more, and the upper limit is preferably 0.2 or less.

The light diffusing particles 47 can be particles made of organic materials or particles made of inorganic materials. The organic material constituting the light-diffusing particles 47 is not particularly limited, for example, polyester, polystyrene, melamine resin, (meth)acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzene resin, etc. Guanamine resin, benzoguanamine-formaldehyde condensation resin, polycarbonate, polyethylene, polyolefin, etc. Among them, a crosslinked acrylic resin is preferably used. In addition, the inorganic material constituting the light-diffusing particles is not particularly limited, and examples thereof include inorganic oxides such as silicon dioxide, aluminum oxide, titanium oxide, tin oxide, antimony-doped tin oxide (ATO), and zinc oxide particles. wait. Among them, silica and/or alumina are preferably used.

After preparing the character blur evaluation device 30 and the optical member 40, the optical member 40 is arranged on the display surface 20A of the display device 20 so that the display device 20 and the optical member 40 become substantially horizontal, and the vertical direction of the display device 20 and the optical member 40 is The camera device 11 is arranged in the direction. Then, in a state where two or more types of stripe patterns 20C to 20E are displayed on the display surface 20A of the display device 20, preferably in a dark room, the stripe pattern 20C is positioned approximately in the center of the image captured by the imaging device 11. The positions of the display device 20 and the optical member 40 are aligned in such a manner, and the light emitted from the display device 20 and transmitted through the optical member 40 is photographed by the imaging device 11 . Next, the display device 20 is moved approximately horizontally, and the positions of the display device 20 and the optical member 40 are aligned so that the stripe pattern 20D is located approximately in the center of the image captured by the imaging device 11. Similarly, the image taken from the display device 20 emits and passes through the light of the optical member 40 . Furthermore, the display device 20 and the optical member 40 are moved approximately horizontally, and the positions of the display device 20 and the optical member 40 are aligned so that the stripe pattern 20E is positioned at approximately the center of the image captured by the imaging device 11. Similarly, The light emitted from the display device 20 and transmitted through the optical member 40 is photographed. In addition, shooting was performed in the state which made the display device 20 and the optical member 40 stand still. Then, by the processing device 12, the brightness change in the direction crossing each stripe pattern 20C-20E is obtained from the captured light, and the contrast of each stripe pattern 20C-20E is obtained from the brightness change, and the character blur is evaluated.

The contrast can be obtained from the following formula (1) in the same manner as above. C=(M-m)/(M+m)...(1) In the formula (1), C is the contrast, M is the maximum value (maximum brightness) of the brightness in the stripe pattern, and m is the minimum value of the brightness (minimum brightness) in the stripe pattern.

According to this embodiment, since two or more types of stripe patterns with different line widths are used, and the contrast ratio is obtained for each stripe pattern, the characters among the two or more types of characters with different thicknesses in the optical member can be separately analyzed. Evaluate the degree of fuzziness. That is, for the same reason as in the first embodiment, it is possible to evaluate the degree of blurring of characters in two or more types of characters with different thicknesses, but in this embodiment, the There is an optical member 40 . Here, if the contrast ratio is also obtained in the state where the optical member 40 is not arranged on the display surface 20A of the display device 20, and the contrast ratio obtained in the state where the optical member 40 is arranged on the display surface 20A of the display device 20, By comparing with the contrast obtained in the state where the optical member 40 is not arranged on the display surface 20A of the display device 20, it is possible to evaluate which type of characters are produced in two or more types of characters with different thickness due to the arrangement of the optical member 40. The degree of text is blurred. Also, if the contrast ratio is also obtained in the state where an optical member different from the optical member 40 is arranged on the display surface 20A of the display device 20, and the contrast ratio is obtained in a state where the optical member 40 is arranged on the display surface 20A of the display device 20 Comparing the contrast with the contrast obtained in the state where an optical member different from the optical member 40 is arranged on the display surface 20A of the display device 20, it can be evaluated separately that the optical member 40 and the optical member 40 are different from each other. Which of the optical components has less or greater blurring of characters in two or more types of characters with different thicknesses.

Concerning the above-mentioned contrast in the state where the optical member 40 is not arranged on the display surface 20A of the display device 20 , in addition to not disposing the optical member 40 on the display surface 20A of the display device 20 , using The contrast obtained in the state of the optical member 40 is obtained by the same method. In this case, since the optical member 40 is not disposed on the display surface 20A of the display device 20, it is natural that the light captured by the imaging device 11 directly captures the light emitted from the display device. Also, regarding the contrast ratio in the state where the optical member different from the optical member 40 is disposed on the display surface 20A of the display device 20, in addition to disposing the optical member different from the optical member 40 on the display surface 20A of the display device 20, use The contrast ratio obtained in the state in which the optical member 40 is arranged on the display surface 20A of the display device 20 is obtained by the same method.

The application of the optical member 40 is not particularly limited, and for example, it may be used in vehicles such as television, personal computer, smart phone, tablet terminal, and car navigation device. In particular, with regard to the optical member with a large value of contrast, the degree of blurring of characters is small, so it is possible to obtain the level of sharpness at which character information can be grasped instantaneously and accurately even while driving. Therefore, an optical member having an extremely large value of contrast is suitable for in-vehicle use.

When the display device is used in a vehicle, if there is incident of external light, it will be difficult for the driver to recognize graphic information or text information such as roads due to the incident of external light. Therefore, it is necessary to exclude external light as much as possible. In addition, when the display device is used in a vehicle, the display surface is pressed with the index finger, so sufficient strength is required. In this embodiment, since the optical member 40 including the anti-glare film 41 and the intermediate member 42 is used, when the intermediate member 42 is a front panel, sufficient strength can be obtained while eliminating external light as much as possible. Therefore, the optical member 40 is particularly suitable for in-vehicle use.

Among the optical components, there are those with good black reproducibility such as bright black or pitch black, but the case of good black reproducibility in optical components is completely different from the case of less blurred characters, so even if the black reproducibility is good In some cases, the degree of ambiguity of the text may not be small.

[third embodiment] Hereinafter, an optical member and a display device according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a schematic configuration diagram of a display device including an optical member of this embodiment, and FIG. 6 is a schematic configuration diagram of a display device including another optical member of this embodiment.

＜<<Optical components and display devices>>> As shown in FIG. 5 , the display device 50 mainly includes: a display panel 60 ; a backlight device 70 disposed on the rear side of the display panel 60 ; and an optical member 80 disposed on the viewer's side of the display panel 60 . The display device 50 only needs to include the display panel 60 and the optical member 80 , and may include a touch panel between the display panel 60 and the optical member 80 . By having a touch panel, a display device having a touch panel function can be obtained. Also, in this embodiment, since the display panel 60 is a liquid crystal display panel, the display device 50 includes the backlight device 70 , but the backlight device 70 may be provided depending on the type of the display panel (display element). The size of the display device 50 may be, for example, not less than 1 inch and not more than 500 inches.

＜＜Display panel＞＞ As shown in FIG. 5 , the display panel 60 includes a display element 61 . The display element 61 is a liquid crystal display element. However, a display element is not limited to a liquid crystal display element, For example, an organic electroluminescence display element etc. may be used. The liquid crystal display element is made by disposing a liquid crystal layer, an alignment film, an electrode layer, a color filter, etc. between two glass substrates.

The display panel 60 has polarizers 62 and 63 disposed on the observer side and the backlight device 70 side of the display element 61, respectively. integration.

The polarizing plates 62 and 63 include: a polarizing element 65 ; a protective film 66 attached to one surface of the polarizing element 65 ; and a protective film 67 attached to the other surface of the polarizing element 65 . The protective films 66 and 67 are for protecting the polarizing element 65 and are made of a light-transmitting base material such as a triacetyl cellulose film (TAC film). Furthermore, the protective film 66 of the polarizing plate 62 may also be provided with a functional layer such as a hard coat on the viewer's side relative to the light-transmitting base material.

As the polarizing element 65, for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, etc. dyed and stretched with iodine etc. are mentioned. . When laminating the polarizing element 65 and the protective films 66 and 67, it is preferable to saponify the protective films 66 and 67 in advance. By subjecting the protective films 66 and 67 to saponification treatment, the adhesion with the polarizer 65 becomes better.

＜＜Backlight unit＞＞ The backlight device 70 illuminates the display panel 60 from the back side of the display panel 60 . A known backlight device can be used as the backlight device 70 , and the backlight device 70 can be either an edge-lit type or a direct-type backlight device.

＜＜Optical components＞＞ The optical member 80 includes: an antiglare film 81 having a concave-convex surface 81A constituting a surface 80A on the viewer side of the optical member 80; the surface 81B side; and the light-diffusing film 83 arranged on the display panel 60 side with respect to the intermediate member 82 . In the state where the optical member 80 is mounted on the display device 50, the concave-convex surface 81A of the anti-glare film 81 constitutes the display surface 50A on the viewer side of the display device 50, and the intermediate member 82 and the light-diffusing film 83 are arranged between the display panel 60 and the anti-glare film. between membranes 81. The optical member 80 may be fixed to the display panel 60 with an adhesive or the like, or may not be fixed.

＜Anti-glare film＞ The anti-glare film 81 includes, for example, a translucent base material 84 and an anti-glare layer 85 disposed on the viewer side of the translucent base material 84 and having a concave-convex surface 85A serving as a concave-convex surface 81A.

The antiglare layer 85 is a layer exhibiting antiglare properties. The anti-glare layer 85 may also exhibit anti-glare properties and other functions. Specifically, the anti-glare layer 85 may be a layer that exhibits anti-glare properties, and also functions such as hard coat properties, anti-reflection properties, antistatic properties, or anti-fouling properties.

In the uneven surface 81A of the anti-glare film 81, the average interval Sm of the unevenness|corrugation which comprises the uneven surface 81A is preferably 0.050 mm or more and 0.300 mm or less. If Sm is less than 0.050 mm, contrast may be poor, and if Sm exceeds 0.300 mm, glare may not be suppressed. Sm is more preferably from 0.060 mm to 0.200 mm. In the uneven surface 81A of the anti-glare film 81 , the average inclination angle θa of the unevenness constituting the uneven surface 81A is preferably not less than 0.1° and not more than 4.0°. If θa is less than 0.1°, the anti-glare property may become insufficient, and if θa exceeds 4.0°, the contrast may be poor. θa is more preferably from 0.5° to 2.0°.

In the uneven surface 81A of the anti-glare film 81, the arithmetic mean roughness Ra of the unevenness constituting the uneven surface 81A is preferably not less than 0.05 μm and not more than 0.40 μm. If Ra is less than 0.05 μm, the anti-glare property may become insufficient, and if Ra exceeds 0.40 μm, the contrast may be poor. Ra is more preferably from 0.10 μm to 0.25 μm. In the uneven surface 81A of the anti-glare film 81, the maximum height roughness Ry of the unevenness constituting the uneven surface 85A is preferably not less than 1.0 μm and not more than 4.0 μm. If Ry is less than 1.0 μm, the anti-glare property may become insufficient, and if Ry exceeds 4.0 μm, the contrast may be poor. Ry is more preferably from 1.5 μm to 3.5 μm. In the uneven surface 81A of the anti-glare film 81, the average roughness Rz of 10 points of the unevenness constituting the uneven surface 81A is preferably 0.30 μm or more and 2.50 μm or less. If Rz is less than 0.30 μm, the anti-glare property may become insufficient, and if Rz exceeds 2.50 μm, the contrast may be poor. Rz is more preferably from 0.50 μm to 1.80 μm.

The above definitions of "Sm", "Ra", "Ry" and "Rz" are based on JIS B0601:1994. The definition of "θa" is based on the operating manual (revised on July 20, 1995) of SE-3400 (manufactured by Kosaka Laboratories), which is a surface roughness measuring device. Specifically, θa is represented by the following formula (2). θa=tan ^-1 Δa...(2) In formula (2), Δa is the aspect ratio that expresses the inclination, which is the sum of the difference between the minimum part and the maximum part (equivalent to the height of each convex part) of each concavo-convex divided by the reference The value derived from the length.

Sm, Ra, Ry, Rz, and θa can all be measured, for example, using SURFCORDER SE-3400, SE-3500, or SE-500 (all manufactured by Kosaka Laboratories). Here, even when θa cannot be directly measured, when Δa can be measured, since θa and Δa have the relationship shown in the above formula (2), Δa can be measured and obtained from the measured Δa θa. In addition, the cut-off wavelengths when measuring Sm etc. were all set to 0.8 mm.

The light-transmitting base material 84 and the anti-glare layer 85 are the same as the light-transmitting base material 44 and the anti-glare layer 45 , so descriptions thereof are omitted here.

＜Intermediate component＞ The intermediate member 82 is the same as the intermediate member 42, and therefore description thereof will be omitted except for the following.

The haze value of the intermediate member 82 is preferably 0.8% or less at the point that the antiglare film 81 and the light diffusion film 83 are preferably transparent. The haze value is based on JIS K7136:2000, using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute) to measure the middle member 82 cut into a size of 10 cm in length and 10 cm in width for 3 times Measured twice, and set as the arithmetic mean of the values obtained from three times of determination.

The total light transmittance of the intermediate member 82 is preferably 80% or more in terms of improving the visibility of the display surface. The total light transmittance is based on JIS K7361-1:1997, using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute) to cut the intermediate member into a size of 10 cm in length and 10 cm in width 82 is measured three times, and is set as the arithmetic mean of the values obtained by carrying out the three measurements.

＜Light diffusion film＞ The light diffusion film 83 is used to diffuse incident light. Although it does not specifically limit as the light-diffusion film 83, For example, the film containing light-diffusion particle|grains, or the film containing a convex structure may be sufficient.

The distance D between the display element 61 and the light-diffusing film 83 is preferably 1 mm or less, more preferably 0.5 mm or less, from the viewpoint of suppressing blurred characters. The distance D between the display element 61 and the light-diffusing film 83 means from the surface of the light-diffusing film 83 side in the display element 61 (for example, the light-diffusing film 83 in the glass plate constituting the light-diffusing film 83 side of the display element 61 The distance from the surface on the side) to the surface on the side of the display element 61 in the light diffusion film 83 . The distance D between the display element 61 and the light-diffusion film 83 measured the distance between the display element 61 and the light-diffusion film 83 of 10 places, and made it the average value of the distance of these 10 places.

The light-diffusing film 83 is the same as the light-diffusing film 43 . Therefore, the light-diffusing film 83 includes, for example, a light-transmitting base material 86 and light-diffusing particles 87 dispersed in the light-transmitting base material 86 .

The haze value of the light-diffusing film 83 is preferably at least 50% from the viewpoint of suppressing glare, more preferably at least 70%, and still more preferably at least 90%. From the viewpoint of suppressing blurred characters, it is more preferably 99% or less, more preferably 95% or less, still more preferably 90% or less. The haze value of the light-diffusion film 83 can be measured by the method similar to the haze value of the intermediate member 82.

(light-transmitting substrate and light-diffusing particles) The translucent base material 86 and the light-diffusing particles 87 are the same as the translucent base material 46 and the light-diffusing particles 47 , so descriptions thereof are omitted here.

＜＜＜Other Display Devices＞＞＞ The display device 50 includes the optical member 80, but the display device 100 shown in FIG. 6 may be used as the display device. In addition, in FIG. 6 , members attached with the same symbols as those in FIG. 5 mean the same members as those shown in FIG. 5 , and thus description thereof will be omitted here.

The display device 100 includes: an anti-glare film 81 disposed on the viewer's side of the display panel 60 and having a concave-convex surface 81A constituting a display surface 100A of the viewer's side of the display device 100 ; an intermediate member 110 disposed on the display panel 60 and the anti-glare film 81 ; and the light-diffusing film 83 , which is arranged between the display panel 60 and the anti-glare film 81 , and is arranged on the display panel 60 side relative to the intermediate member 110 .

＜＜Intermediate component＞＞ The intermediate member 110 is composed of a touch panel 111 and an air layer 112 located closer to the display panel 60 than the touch panel 111 . Since the intermediate member 110 is provided with the touch panel 111 , a touch panel function can be provided to the display device 100 . As the touch panel 111, a known touch panel can be used, and a front panel may also be provided. The thickness of the air layer 112 is preferably not less than 0.1 mm and not more than 3.0 mm. As long as the thickness of the air layer 112 is 0.1 mm or more, watermarks caused by partial contact between the touch panel 111 and the light diffusion film 83 can be suppressed, and if the thickness is 3.0 mm or less, the thickness of the display device 100 can be suppressed from changing. thick. The thickness of the air layer 112 was measured randomly at 10 locations, and was set as the average value.

According to this embodiment, since the optical member 80 or the display device 100 is equipped with the light-diffusion film 83, the glare which arises by disposing the anti-glare film 81 can be suppressed. Also, the inventors of the present invention have made diligent studies on the degree of blurred characters caused by disposing the light-diffusing film. As a result, they have found that the degree of blurred characters varies with the thickness of the characters. Specifically, when the distance from the display element to the light-diffusing film is large, the degree of blurring of characters is greater than when the distance from the display element to the light-diffusing film is small. On the other hand, it was found that the glare does not depend on the distance from the display element to the light-diffusing film. According to this embodiment, since the light-diffusing film 83 is arranged on the side of the display panel 60 rather than the intermediate members 82 and 110, compared with the case where the light-diffusing film is arranged between the intermediate member and the anti-glare film, the distance from the display element to the light The distance between the diffuser membranes is smaller. Thereby, the degree of blurring of the characters can be made extremely small without depending on the thickness of the characters displayed on the display surface 60A of the display panel 60, so it is possible to suppress the blurring of the characters regardless of the thickness of the characters while suppressing glare. .

The application of the display device 50, 100 or the optical member 80 is not particularly limited, for example, it can be used in a vehicle such as a TV, a personal computer, a smart phone, a tablet terminal, and a car navigation device. In particular, since the display device 50, 100 or the optical member 80 has a small degree of blurring of characters, it is possible to obtain a level of clarity at which character information can be grasped instantaneously and accurately even while driving. Therefore, the display device 50, 100 or the optical member 80 is suitable for in-vehicle use.

When the display device is used in a vehicle, if there is incident of external light, it will be difficult for the driver to recognize graphic information or text information such as roads due to the incident of external light. Therefore, it is necessary to exclude external light as much as possible. In addition, when the display device is used in a vehicle, the display surface is pressed with the index finger, so sufficient strength is required. In this embodiment, since the optical member 80 including the anti-glare film 81 and the intermediate member 82 is used, and the intermediate member 82 is a front panel, sufficient strength can be obtained while eliminating external light as much as possible. Therefore, the optical member 80 is particularly suitable for in-vehicle use.

The degree of character blurring of the display devices 50 and 100 and the optical member 80 can be evaluated visually, and it is preferable to evaluate by the following methods from the viewpoint of accurate evaluation. In addition, below, the method of evaluating the character blurring of the optical member 80 and the display device 50 is demonstrated, but the character blurring of the display device 100 can also be evaluated by the same method.

＜＜Appraisal Method for Text Blurring of Optical Components＞＞ The character blurring of the optical member 80 can be evaluated by the same method as the second embodiment using the same character blurring evaluation device as the character blurring evaluation device 30 described in the second embodiment. Specifically, the character blur evaluation device similar to the character blur evaluation device 30 and the optical member 80 are prepared. The blurred character evaluation device has the same configuration as the blurred character evaluation device, so it includes the following devices: a display device having a display surface capable of displaying two or more types of stripe patterns with different line widths; an imaging device disposed on the display of the display device above the surface; and a processing device electrically connected to the imaging device. Furthermore, the display device, imaging device, and processing device are the same as the display device 20, the imaging device 11, and the processing device 12, and the stripe patterns displayed on the display surface of the display device are also the same as the stripe patterns 20C-20E, so here Description is also omitted. Then, the display device and the optical member 80 of the text blur evaluation device are arranged on the display surface of the display device and the display device so that the display device and the optical member 80 are substantially horizontal, and the imaging device is arranged in the vertical direction of the display device and the optical member 80 . In addition, the optical member 80 is arrange|positioned so that the light-diffusion film 83 may become the display surface side of a display device. Then, in a state where two or more types of stripe patterns with different line widths are displayed on the display surface of the display device, preferably in a dark room, one stripe pattern is located in the approximate center of the image captured by the imaging device. The positions of the display device and the optical member 80 are aligned, and the light emitted from the display device and passed through the optical member 80 is photographed by an imaging device. Next, move the display device substantially horizontally, and align the positions of the display device and the optical member 80 so that other fringe patterns are located in the approximate center of the image captured by the imaging device. Optical member 80 of light. The photographing was carried out in a state where the display device and the optical member 80 were left still. Then, by using the processing device, the brightness change in the direction crossing each stripe pattern is obtained from the captured light, and the contrast of each stripe pattern is obtained from the brightness change to evaluate the character blur.

According to this evaluation method, since two or more types of fringe patterns with different line widths are used and the contrast ratio is obtained for each fringe pattern, one of two or more types of characters with different thicknesses in the optical member 80 can be separately evaluated. Evaluate the degree of text fuzziness. In addition, if the contrast ratio is also obtained in the state where the optical member 80 is not arranged on the display surface of the display device, and the contrast ratio obtained in the state where the optical member 80 is arranged on the display surface of the display device is compared with that obtained on the display surface of the display device. Comparing the contrast obtained in the state where the optical member 80 is not arranged on the display surface, it is possible to evaluate the degree of character blurring caused by the arrangement of the optical member 80 in two or more types of characters with different thicknesses. Also, if the contrast ratio is also obtained in a state where an optical member different from the optical member 80 (for example, an optical member with a light-diffusing film disposed between an anti-glare film and an intermediate member) is disposed on the display surface of the display device, and Comparing the contrast obtained in the state where the optical member 80 is arranged on the display surface of the display device with the contrast obtained in the state where an optical member different from the optical member 80 is arranged on the display surface of the display device, it can be respectively It was evaluated which one of the optical member 80 and the optical member different from the optical member 80 has a smaller or larger degree of character blur among two or more types of characters with different thicknesses.

＜＜Text blur evaluation method for display devices＞＞ Although the character blurring of the optical member 80 was evaluated above, it is also possible to evaluate the character blurring of the display device 50 including the optical member 80 . The character blurring of the display device 50 can be evaluated by the same method as the first embodiment using the same character blurring evaluation device as the character blurring evaluation device 10 described in the first embodiment, so the description is omitted here.

Also in this embodiment, since two or more stripe patterns with different line widths are used, and the contrast ratio is obtained for each stripe pattern, the reason is the same as that described in the first embodiment and the second embodiment. For this reason, it is possible to evaluate the degree of blurring of characters in two or more types of characters with different thicknesses in the optical member 80 and the display device 50 . [Example]

In order to demonstrate this invention in detail, although an Example is given and demonstrated below, this invention is not limited to these descriptions. In addition, the following evaluation or measurement is carried out at least by visual inspection and no abnormal site (site without large foreign matter, scratches, dirt or wrinkles, etc.).

<<Example A>> <Preparation of composition for antiglare layer> First, each component was prepared so that it might become the composition shown below, and the composition 1 for antiglare layers was obtained. (Composition 1 for antiglare layer) ・Multifunctional acrylate monomer: 80 parts by mass ・Photopolymerization initiator: 5 parts by mass ・Silicone-based leveling agent: 0.1 parts by mass ・Spherical polyacrylic acid-styrene particles (average particle diameter 3.5 μm, refractive index 1.52): 12 parts by mass ・Reactive functional group introduced silica ultrafine particles (solid content 30%, solvent (methyl isobutyl ketone)): 120 parts by mass ・Toluene: 135 parts by mass

＜Preparation of Light Diffusion Film＞ Each component was prepared so that it might become the composition shown below, and the composition 1 for light-diffusion films was obtained. (Composition 1 for light diffusion film) ・Acrylic polyol: 80 parts by mass ・Isocyanate hardener: 16 parts by mass ・Polymethyl methacrylate particles (average particle size: 10 μm): 100 parts by mass ・Butyl acetate: 100 parts by mass ・Methyl ethyl ketone: 100 parts by mass

<Sample 1> A 60 μm-thick triacetyl cellulose resin film (manufactured by Fuji Film Co., Ltd., TD60UL) was prepared as a light-transmitting base material, and the antiglare layer composition 1 was coated on the triacetyl cellulose resin film On one side, forming a coating film. Next, for the formed coating film, dry air at 50°C was circulated at a flow rate of 0.2 m/s for 15 seconds, and then dry air at 70°C was circulated at a flow rate of 10 m/s for 30 seconds to make it Dry to evaporate the solvent in the coating film, and then irradiate ultraviolet rays in a nitrogen atmosphere (oxygen concentration below 200 ppm) so that the cumulative light intensity becomes 100 mJ/ ^cm2 to harden the coating film, thereby forming a rough surface The film thickness (when hardened) is an anti-glare layer of 4.0 μm to make an anti-glare film.

On the other hand, Composition 1 for a light-diffusing film was applied to one surface of a polyethylene terephthalate film (PET film) with a thickness of 50 μm so that the film thickness after drying was 16 μm, and the dried to produce a light-diffusing film.

After obtaining the anti-glare film and light-diffusing film, remove the glass plate and other touch panel elements that are the front panel of a commercially available tablet terminal (pixel density: 264 ppi), and laminate the above-made light-diffusing film in order toward the viewer side film, a colorless transparent glass plate with a thickness of 1 mm (haze value 0.2% and total light transmittance 92%) and the anti-glare film produced above to obtain the display device of Sample 1. In addition, the anti-glare film is arranged so that the concave-convex surface becomes the observation side.

＜Sample 2＞ In sample 2, the colorless transparent glass plate with a thickness of 1 mm used in sample 1, the light diffusion film produced in sample 1, and the anti-glare film produced in sample 1 were laminated in order toward the observer, except In addition, the display device of the sample 2 was obtained similarly to the sample 1.

＜Sample 3＞ In sample 3, the colorless transparent glass plate with a thickness of 1 mm used in sample 1 and the anti-glare film produced in sample 1 were laminated sequentially toward the viewer side, and sample 3 was obtained in the same manner as sample 1. The display device.

＜Sample 4＞ In Sample 4, the display surface of a commercially available smartphone (pixel density 326 ppi) is placed on the display surface from the display surface side toward the viewer side, and the light-diffusing film produced in Sample 1 is laminated sequentially. The thickness used in Sample 1 An optical component made of a 1 mm colorless transparent glass plate and the anti-glare film produced in Sample 1. In addition, the anti-glare film is arranged so that the concave-convex surface becomes the viewing side.

＜Sample 5＞ In sample 5, the display surface of the commercially available smart phone used in sample 4 is stacked sequentially from the display surface side to the observer side, colorless transparent glass plate with a thickness of 1 mm used in sample 1, sample An optical member made of the light-diffusing film produced in 1 and the anti-glare film produced in sample 1. In addition, the anti-glare film is arranged so that the concave-convex surface becomes the observation side.

＜Sample 6＞ In sample 6, the display surface of the commercially available smart phone used in sample 4 is stacked sequentially from the display side to the viewer side, and the colorless transparent glass plate with a thickness of 1 mm used in sample 1 and the sample An optical member made of the anti-glare film produced in 1. In addition, the anti-glare film is arranged so that the concave-convex surface becomes the viewing side.

＜Glare Evaluation＞ Arrange the display devices of samples 1 to 3 and the display devices equipped with the optical components of samples 4 to 6 in a substantially horizontal manner, and light up each display device. The surface of each display device and the surface of each optical member of Samples 4 to 6 were inspected from various angles from top to bottom and left and right within a distance of about 30 cm, and whether glare occurred was evaluated visually. The evaluation criteria are as follows. ◯: No glare was confirmed, or some glare was confirmed, but it was at a level that did not pose a problem practically. X: Glare was clearly confirmed.

＜Text Blurred Evaluation (1)＞ In each of the display devices of samples 1 to 3 and the display devices equipped with the optical members of samples 4 to 6, in the state where three kinds of stripe patterns with different line widths are displayed on the display surface of each display device, for each stripe The pattern finds the contrast. Specifically, first, on the display surface of a personal computer, stripe patterns were produced in such a manner that the following stripe patterns were displayed on the display devices of samples 1 to 3 and the display devices equipped with optical members of samples 4 to 6, and the stripe patterns Send it to each display device produced, and use the application software to set the stripe pattern to be displayed on the display surface of the display device. Thereafter, the display devices of samples 1 to 3 and the display devices mounted with the optical members of samples 4 to 6 were arranged so that they became substantially horizontal, and a CCD camera (Point Gray Co., Ltd. BlackFly 1.3 M pixels, lens; COMPUTAR f=16 mm, F/1.4, type 2/3). Then, in each display device, make the first stripe pattern whose line width is 1 pixel, the number of lines is 30, the line length is 1 cm and the line interval is 1 pixel, the line width is 2 pixels, the number of lines The second stripe pattern is 15, the line length is 1 cm, and the line interval is 2 pixels, and the line width is 4 pixels, the number of lines is 8, the line length is 1 cm, and the line interval is 4 pixels. The stripe pattern is displayed on the display surface of each display device. Then, in the dark room, among the display devices of samples 1 to 3, the position of the display device was aligned so that the first stripe pattern was located in the approximate center of the image captured by the CCD camera, and the image was taken by the CCD camera. The light emitted from the display device. Next, the display device is moved substantially horizontally, the position of the display device is aligned so that the second stripe pattern is located in the approximate center of the image captured by the CCD camera, and light emitted from the display device is photographed in the same manner as above. Furthermore, the display device was moved approximately horizontally, the position of the display device was aligned so that the third stripe pattern was located approximately in the center of the image captured by the CCD camera, and light emitted from the display device was photographed in the same manner as above. In addition, in the display device equipped with each optical member of samples 4 to 6, the position of the display device equipped with the optical member was aligned so that the first stripe pattern was located in the approximate center of the image captured by the CCD camera, The light emitted from the display device and passed through the optical component is photographed by a CCD camera. Next, the display device equipped with the optical member is moved approximately horizontally, and the position of the display device equipped with the optical member is aligned so that the second stripe pattern is located in the approximate center of the image captured by the CCD camera, and the above-mentioned Similarly, the light emitted from the display device and transmitted through the optical member is photographed. Furthermore, the display device equipped with the optical member is moved approximately horizontally, and the position of the display device equipped with the optical member is aligned so that the third stripe pattern is located in the approximate center of the image captured by the CCD camera, and the above-mentioned Similarly, the light emitted from the display device and transmitted through the optical member is photographed. In addition, shooting was performed in the state which made the display device stand still. The distance between the CCD camera and the anti-glare film is set to 200 mm, and the focus of the CCD camera is adjusted in such a way that each fringe pattern becomes clearest when no anti-glare film or light diffusion film is installed. The light captured by the CCD camera is captured in the form of an image to a personal computer as a processing device, and the brightness change in the direction crossing each stripe pattern is calculated from the captured light. The brightness at this time was set as the average value of the brightness within the length of the line constituting the stripe pattern along the direction of the stripe pattern (vertical direction in FIG. 2 ). Furthermore, the measured brightness is a relative value without a unit. Then, the contrast of each stripe pattern was obtained from the change in luminance using the above formula (1).

＜Text Blurred Evaluation (2)＞ In each of the display devices of samples 1 to 3 and the display devices equipped with the optical components of samples 4 to 6, three types in which the size of characters is different and the line width is about 1 pixel, about 2 pixels, and about 4 pixels The uppercase letters are the characters of "ABCDEF" (hereinafter, the characters with a line width of about 1 pixel are called "first characters", the characters with a line width of about 2 pixels are called "second characters", and the characters with a line width of about 3 pixels The characters on the left and right sides of the pixels are called "third characters") displayed on the display surface of each display device, in a dark room, in each display device of samples 1 to 3, within a distance of about 30 cm from the display surface Various angles of up and down, left and right, observe the display surface visually, in the display device equipped with each optical component of samples 4 to 6, within a distance of about 30 cm from the surface of the optical component, from various angles of up and down, left and right , the display surface was observed visually through the optical member, and whether or not the characters were blurred was evaluated. The evaluation criteria are as follows. In addition, when the display device is used in a vehicle, it is often observed from an oblique direction at a distance of about 60 cm or more from the display surface of the display device. Under more stringent conditions, the word blur is evaluated, and observations are made from various angles from top to bottom, left and right, within a distance of about 30 cm from the display surface or the surface of the optical component. ◎: There is no problem with the legibility of characters at all. ◯: Slight blurring was observed, but there was no problem with the legibility of characters. △: Blurred characters were observed, and the characters were slightly incomprehensible. X: Characters are clearly blurred, and characters are difficult to recognize.

The results are shown in Table 1 and Table 2 below. [Table 1] Glare evaluation Text Fuzzy Evaluation (1) 1st stripe pattern 2nd stripe pattern 3rd stripe pattern maximum brightness minimum brightness contrast maximum brightness minimum brightness contrast maximum brightness minimum brightness contrast sample 1 ○ 111.8 37.1 50.1% 138.3 18.6 76.3% 136.4 15.0 80.1% sample 2 ○ 76.0 61.0 11.0% 97.3 40.6 41.1% 116.6 22.1 68.2% sample 3 x 191.9 11.2 88.9% 208.3 13.1 88.1% 190.9 15.2 85.3% sample 4 ○ 67.7 63.0 3.6% 84.0 48.3 27.0% 110.4 24.5 63.7% Sample 5 ○ 66.0 64.4 1.2% 71.3 62.1 6.9% 90.1 43.9 34.4% Sample 6 x 104.3 42.6 42.0% 126.8 22.3 70.1% 130.5 18.0 75.8%

[Table 2] Text Fuzzy Evaluation (2) first text 2nd text 3rd text sample 1 ○ ◎ ◎ sample 2 △ ○ ◎ sample 3 ◎ ◎ ◎ Sample 4 x △ ◎ Sample 5 x x ○ Sample 6 ○ ◎ ◎

Hereinafter, the results will be described. As shown in Table 1, in the display devices of Sample 1 and Sample 3, the contrast ratios in the first to third stripe patterns were all higher than a certain level. On the other hand, in the display device of sample 2, although the contrast in the 2nd and 3rd stripe patterns was high to some extent, the contrast in the 2nd stripe pattern was low. On the other hand, as shown in Table 2, in the first to third characters displayed on the display devices of sample 1 and sample 3, and the second and third characters displayed on the display device of sample 2, the characters are fully recognizable. There was no problem, or some blurring was observed, but there was no problem with the legibility of the characters, but in the first character displayed on the display device of Sample 2, the characters were blurred and the characters were slightly difficult to understand. Therefore, it was confirmed that the contrast values of the display devices of samples 1 to 3 corresponded to the results of the visual evaluation in blurred characters.

Also, as shown in Table 1, in the display device of Sample 6, the contrast ratios in the first to third stripe patterns were all high to a certain level or more. In contrast, in the display device of Sample 4, the contrast in the third stripe pattern was higher than a certain level, but the contrast in the first and second stripe patterns was low. Also, in the display device of Sample 5, although the contrast in the third stripe pattern was high to some extent, the contrast in the first and second stripe patterns was low. On the other hand, as shown in Table 2, in the first to third characters displayed on the display device of sample 6 and the third character displayed on the display devices of samples 4 and 5, there was no problem with the legibility of the characters at all. Or some blurring is observed, but there is no problem with the legibility of the characters, but in the first and second characters displayed on the display devices of samples 4 and 5, the characters are blurred, the characters are slightly difficult to understand, or there are obvious characters Blurred, hard to read text. Therefore, it was confirmed that the contrast values of the display devices of samples 4 to 6 corresponded to the results of the visual evaluation in blurred characters.

<<Example B>> <Preparation of composition for antiglare layer> First, each component was prepared so that it might become the composition shown below, and the composition 2 for antiglare layers was obtained. (Composition 2 for antiglare layer) ・Mixture of neopentylthritol triacrylate and neopentylthritol tetraacrylate (product name "KAYARAD PET-30", manufactured by Nippon Kayaku): 38 parts by mass ・Isocyanuric acid EO modified di- and triacrylates (product name "M-313", manufactured by Toagosei Co.): 22 parts by mass ・Photopolymerization initiator (product name "Irgacure 184", manufactured by BASF Corporation): 5 parts by mass ・Silicone-based leveling agent (product name "TSF4460", manufactured by Momentive Advanced Materials): 0.1 parts by mass ・Translucent particles (spherical polyacrylic acid-styrene copolymer, average particle size 3.5 μm, refractive index 1.52): 12 parts by mass ・Inorganic ultrafine particles (silicon dioxide with reactive functional groups introduced on the surface, average primary particle size 12 nm, solvent (methyl isobutyl ketone), solid content 30%): 120 parts by mass ・Toluene: 135 parts by mass

<Example B1> A 60-μm-thick triacetyl cellulose resin film (manufactured by Fuji Film Co., Ltd., TD60UL) was prepared as a light-transmitting substrate, and the composition 2 for an antiglare layer was coated on the triacetyl cellulose resin One side of the film to form a coating film. Next, for the formed coating film, dry air at 50°C was circulated at a flow rate of 0.2 m/s for 15 seconds, and then dry air at 70°C was circulated at a flow rate of 10 m/s for 30 seconds to make it Dry to evaporate the solvent in the coating film, and then irradiate ultraviolet rays in a nitrogen atmosphere (oxygen concentration below 200 ppm) so that the cumulative light intensity becomes 100 mJ/ ^cm2 to harden the coating film, thereby forming a rough surface The film thickness (when hardened) is an anti-glare layer of 5.0 μm to make an anti-glare film.

On the concave-convex surface of the produced antiglare film, Sm, Ra, Ry, and Rz were measured according to JIS B0601:1994. As a result, Sm was 0.094 mm, Ra was 0.16 μm, Ry was 1.72 μm, and Rz was 0.91 μm. In addition, θa was measured on the concave-convex surface of the produced anti-glare film in accordance with the instruction manual (revised on July 20, 1995) of SE-3400 (manufactured by Kosaka Laboratories), which is a surface roughness measuring device, and the results were as follows: θa is 1.37°. Measurements of Sm, θa, Ra, Ry, and Rz were carried out using SE-3400 (manufactured by Kosaka Laboratories), which is a surface roughness measuring instrument, under the following measurement conditions. 1) The stylus of the surface roughness detection part (trade name SE2555N (2 μ standard) manufactured by Kosaka Laboratory) ・The radius of curvature of the front end is 2 μm, the apex angle is 90 degrees, and the material is diamond 2) Measurement conditions of the surface roughness tester ・Basic length (cut-off value λc of roughness curve): 0.8 mm ・Evaluation length (reference length (cutoff value λc)×5): 4.0 mm ・Feed speed of stylus: 0.5 mm/s ・Pre-length: (cut-off value λc)×2 ・Vertical magnification: 10000 times ・Horizontal magnification: 10 times ・Slide: Use ・Cut filter type: Gaussian ・Leveling: All information ・Sampling mode: c＝1500 ・Dead zone level: 10% ・JIS pattern: JIS1994 ・tp/PC curve: regular line

On the other hand, the light-diffusing film composition 1 used in the column of Example A was applied to a polyethylene terephthalate film (PET film) and let it dry to make a light diffusion film. In addition, as a result of measuring the haze value of the light-diffusion film, the haze value was 92%. The haze value of the light-diffusing film is based on JIS K7136:2000, using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute), to cut light into a size of 10 cm in length and 10 cm in width The diffusion film was measured three times, and the arithmetic mean value of the values obtained by performing the three measurements was used.

After the anti-glare film and the light-diffusing film were obtained, the above-produced diffusion film, the glass plate with a thickness of 1 mm, and the above-produced anti-glare film were sequentially laminated to obtain the optical member of Example B1. In addition, the anti-glare film is arrange|positioned so that a concave-convex surface may become the surface of an optical member.

<Example B2> In Example B2, first, the touch panel on the surface of the iPad (4th generation) (manufactured by Apple Inc., 264 ppi) was removed, the polarizer on the surface of the liquid crystal display panel was peeled off, and a flat polarizer. Then, the light-diffusion film produced in Example B1 was affixed thereon. Thereafter, the detached touch panel was placed on the light diffusion film again through an air layer (air gap) with a thickness of 0.7 mm, and the touch panel produced in Example B1 was placed in such a manner that the concave-convex surface became the viewer's side. An anti-glare film was attached to the surface (observer side) of the touch panel to obtain the display device of Example B2. Also, a display device identical to the display device of the above-mentioned embodiment B2 was produced separately, and the display device produced separately was destroyed, and the distance between the display element of the display device and the light-diffusing film was measured. As a result, the distance was 0.3 mm. In addition, the distance between the display element and the light-diffusion film measured the distance between the display element and the light-diffusion film of 10 places, and made it the average value of the distance of these 10 places.

<Comparative example B1> In Comparative Example B1, a glass plate with a thickness of 1 mm, the light-diffusing film produced in Example B1, and the antiglare film produced in Example B1 were laminated in this order to obtain an optical member. In addition, the anti-glare film is arrange|positioned so that a concave-convex surface may become the surface of an optical member.

＜Comparative example B2＞ In Comparative Example B2, a glass plate with a thickness of 1 mm and the anti-glare film produced in Example B1 were laminated in this order to obtain an optical member. In addition, this optical member does not have a light-diffusion film, and the anti-glare film is arrange|positioned so that an uneven|corrugated surface may become a surface.

＜Comparative example B3＞ In Comparative Example B3, a display device was obtained in the same manner as in Example B2 except that the light-diffusing film was placed on the display panel side rather than the air layer, and the light-diffusing film was placed between the anti-glare film and the touch panel. . The distance between the display element of the display device and the light-diffusing film was 2 mm. In addition, this distance was measured by the same method as Example B2.

<Comparative example B4> In comparative example B4, except not having arrange|positioned a light-diffusion film, it carried out similarly to Example B2, and obtained the display device.

＜Glare Evaluation＞ In Example B1 and Comparative Examples B1 and B2, the glass plate including the surface of the iPad (4th generation) (manufactured by Apple Inc., 264 ppi) was placed so that the concave-convex surface of the anti-glare film was on the viewer side The touch panel (also used as the front panel) was removed, and the optical components of Example B1 and Comparative Examples B1 and B2 were placed on the display surface of the liquid crystal display panel to obtain a display device equipped with optical components. Each display device of the optical member is arranged in a substantially horizontal manner, and each display device equipped with the optical member is turned on. In a dark room, within a distance of about 30 cm from the surface of each optical member, from various angles up and down, left and right , whether or not glare occurred was evaluated by visual inspection. Also, in Example B2 and Comparative Examples B3 and B4, each display device was arranged in a substantially horizontal manner, and each display device was turned on, in a dark room, at a distance of about 30 cm from the surface of each display device. From various angles from top to bottom, left and right within the distance, visually evaluate whether glare occurs. The evaluation criteria are as follows. ◯: No glare was confirmed, or some glare was confirmed, but it was at a level that did not pose a problem practically. X: Glare was clearly confirmed.

＜Text Blurred Evaluation (1)＞ In Example B1 and Comparative Examples B1 and B2, in the state where three kinds of fringe patterns with different line widths were displayed on the display surface of the display device equipped with the optical member used in the above-mentioned glare evaluation, the fringe pattern was obtained for each fringe pattern. out of contrast. Also, in Example B2 and Comparative Examples B3 and B4, in the state where three kinds of stripe patterns with different line widths are displayed on the display surfaces of the display devices of Embodiment B2 and Comparative Examples B3 and B4, for each stripe pattern, out of contrast. Specifically, first, on the display surface of a personal computer, the display device equipped with each optical member of Example B1 and Comparative Examples B1 and B2 and each display of Example B2 and Comparative Examples B3 and B4 were displayed in the following stripe pattern. The stripe pattern is produced by means of the device, and the stripe pattern is transmitted to each display device produced, and the stripe pattern is set to be displayed on the display surface of the display device by the application software. Thereafter, the display devices equipped with the optical members of Example B1 and Comparative Examples B1 and B2, and the display devices of Example B2 and Comparative Examples B3 and B4 were arranged in a substantially horizontal manner, and each display device A CCD camera (BlackFly 1.3 M pixels, lens, COMPUTAR f=16 mm, F/1.4, 2/3 type, Point Gray company) is arranged in the vertical direction of the device. Then, make the first stripe pattern whose line width is 1 pixel, the number of lines is 30, the line length is 1 cm and the line interval is 1 pixel, the line width is 2 pixels, the number of lines is 15, the line length is 1 cm, and the line interval is 1 pixel. The second stripe pattern with a length of 1 cm and a line interval of 2 pixels, and the third stripe pattern with a line width of 4 pixels, the number of lines 8, a line length of 1 cm, and a line interval of 4 pixels are displayed on the on-board The display surface of the display panel of each display device having the optical member of Example B1 and Comparative Examples B1 and B2, and the display surface of the display panel of each display device of Example B2 and Comparative Examples B3 and B4. Then, in the darkroom, in each display device equipped with the optical components of Example B1 and Comparative Examples B1 and B2, the optical components equipped with the optical components were placed in such a manner that the first stripe pattern was located in the approximate center of the image captured by the CCD camera. The position of the display device of the component is aligned, and the light emitted from the display device and passed through the optical component is photographed by a CCD camera. Next, the display device equipped with the optical member is moved approximately horizontally, and the position of the display device equipped with the optical member is aligned so that the second stripe pattern is located in the approximate center of the image captured by the CCD camera, and the above-mentioned Similarly, the light emitted from the display device and transmitted through the optical member is photographed. Furthermore, the display device equipped with the optical member is moved approximately horizontally, and the position of the display device equipped with the optical member is aligned so that the third stripe pattern is located in the approximate center of the image captured by the CCD camera, and the above-mentioned Similarly, the light emitted from the display device and transmitted through the optical member is photographed. In addition, imaging was performed in the state which made the display device which mounted the optical member stand still. Also, in the display devices of Example B2 and Comparative Examples B3 and B4, the position of the display device was aligned so that the first stripe pattern was located in the approximate center of the image captured by the CCD camera, and was photographed by the CCD camera. The light emitted from the display device. Next, the display device is moved substantially horizontally, the position of the display device is aligned so that the second stripe pattern is located in the approximate center of the image captured by the CCD camera, and light emitted from the display device is photographed in the same manner as above. Furthermore, the display device was moved approximately horizontally, the position of the display device was aligned so that the third stripe pattern was located approximately in the center of the image captured by the CCD camera, and light emitted from the display device was photographed in the same manner as above. The distance between the CCD camera and the anti-glare film is set to 200 mm, and the focus of the CCD camera is adjusted in such a way that the fringe pattern becomes clearest when no anti-glare film or light diffusion film is installed. The light captured by the CCD camera is captured in the form of an image to a personal computer as a processing device, and the brightness change in the direction crossing each stripe pattern is calculated from the captured light. The brightness at this time was set as the average value of the brightness within the length of the line constituting the stripe pattern along the direction of the stripe pattern (vertical direction in FIG. 2 ). Furthermore, the measured brightness is a relative value without a unit. Then, the contrast of each stripe pattern was obtained from the change in luminance using the above formula (1).

＜Text Blurred Evaluation (2)＞ In each display device equipped with the optical member of Example B1 and Comparative Examples B1 and B2, and each display device of Example B2 and Comparative Examples B3 and B4, when the size of the characters is different and the line width is about 1 pixel, respectively, The three capital letters of about 2 pixels and about 4 pixels are the characters of "ABCDEF" (hereinafter, the characters with a line width of about 1 pixel are called "the first character", and the characters with a line width of about 2 pixels are called " The second character", the character with a line width of about 3 pixels is called "the third character") is displayed on the display surface of the display panel of each display device, under a dark room, on a vehicle equipped with Example B1 and Comparative Example In each display device of the optical member of B1 and B2, within a distance of about 30 cm from the surface of the optical member, the display surface is observed visually through the optical member from various angles from up to down, left and right, in Examples B2 and In each of the display devices of Comparative Examples B3 and B4, the display surface was visually observed from various angles of up and down, left and right within a distance of about 30 cm from the display surface, and whether the characters were blurred was evaluated. The evaluation criteria are as follows. In addition, when the display device is used in a vehicle, it is often observed from an oblique direction at a distance of about 60 cm or more from the display surface of the display device. Under more stringent conditions, the word blur is evaluated, and observations are made from various angles from top to bottom, left and right, within a distance of about 30 cm from the surface of the optical component or the display surface. ◎: There is no problem with the legibility of characters at all. ◯: Slight blurring was observed, but there was no problem with the legibility of characters. △: Blurred characters were observed, and the characters were slightly incomprehensible. X: Characters are clearly blurred, and characters are difficult to recognize.

The results are shown in Table 3 and Table 4 below. [table 3] Glare evaluation Text Fuzzy Evaluation (1) 1st stripe pattern 2nd stripe pattern 3rd stripe pattern maximum brightness minimum brightness contrast maximum brightness minimum brightness contrast maximum brightness minimum brightness contrast Example B1 ○ 111.8 37.1 50.1% 138.4 18.6 76.3% 136.4 15.1 80.1% Example B2 ○ 111.0 40.0 47.0% 134.6 19.2 75.0% 146.5 18.9 77.1% Comparative Example B1 ○ 91.5 50.6 28.8% 94.2 40.2 40.2% 111.2 36.0 51.1% Comparative Example B2 x 188.6 12.2 87.8% 206.3 13.5 87.7% 188.8 15.7 84.6% Comparative Example B3 ○ 81.0 49.2 24.4% 92.0 43.9 35.4% 113.5 40.5 47.4% Comparative Example B4 x 187.6 14.5 85.7% 208.2 16.9 85.0% 194.3 16.2 84.6%

[Table 4] Text Fuzzy Evaluation (2) 1st stripe pattern 2nd stripe pattern 3rd stripe pattern Example B1 ○ ◎ ◎ Example B2 ○ ◎ ◎ Comparative Example B1 x △ ○ Comparative Example B2 ◎ ◎ ◎ Comparative Example B3 x △ ○ Comparative Example B4 ◎ ◎ ◎

Hereinafter, the results will be described. As shown in Table 3, since the optical member of the comparative example B2 did not have a light-diffusion film, glare was confirmed. On the other hand, since the optical member of Example B1 was equipped with a light-diffusion film, glare was suppressed. Also, regarding the optical member of Comparative Example B1, since the light-diffusing film is arranged between the glass plate and the anti-glare film, the contrast in the third stripe pattern is relatively high, but the contrast ratio in the first and second stripe patterns is relatively high. Contrast is low. On the other hand, in the optical member of Example B1, all the contrasts in the 1st - 3rd stripe patterns were high. In addition, the value of the contrast in the optical member of Example B1 and Comparative Examples B1 and B2 corresponded to the result of the visual evaluation in blurred characters. Therefore, in the optical member of Example B1, it was confirmed that glare can be suppressed, and blurring of characters can be suppressed regardless of the thickness of characters.

Moreover, as shown in Table 3, since the display device of the comparative example B4 did not have a light-diffusion film, glare was confirmed. On the other hand, since the display device of Example B2 was equipped with a light-diffusion film, glare was suppressed. Also, regarding the display device of Comparative Example B3, since the light-diffusing film was disposed between the touch panel and the anti-glare film, the contrast in the third stripe pattern was somewhat high, but in the first and second stripe patterns The contrast is low. On the other hand, in the display device of Example B2, all the contrast ratios in the first to third stripe patterns were high. In addition, the value of the contrast in the optical member of Example B2 and Comparative Examples B3 and B4 corresponded to the result of the visual evaluation in blurred characters. Therefore, in the display device of Example B2, it was confirmed that glare can be suppressed, and blurring of characters can be suppressed regardless of the thickness of the characters.

10, 30: text fuzzy evaluation device 11: camera device 12: Processing device 20, 50, 100: display device 21: Display components 20A, 50A, 100A: display surface 20B: line 20C～20E: stripe pattern 40, 80: Optical components 41, 81: anti-glare film 42, 82: intermediate components 43, 83: light diffusion film LW: line width LL: length of line LD: Interval between lines

[FIG. 1] It is a figure for demonstrating the character blur evaluation method of the display device of 1st Embodiment. [ Fig. 2 ] is a diagram schematically showing a stripe pattern displayed on the display surface of the display device in Fig. 1 . [Fig. 3] is an enlarged view of a part of the stripe pattern. [FIG. 4] It is a figure for demonstrating the character blur evaluation method of the optical member of 2nd Embodiment. [ Fig. 5 ] is a schematic configuration diagram of a display device including an optical member according to a third embodiment. [ Fig. 6 ] is a schematic configuration diagram of a display device provided with another optical member according to the third embodiment.

10: Word fuzzy evaluation device

11: camera device

12: Processing device

20: Display device

20A: display surface

21: Display components

Claims (6)

An optical member disposed on the viewer side of a display panel provided with a display element, characterized by comprising: an anti-glare film having a concave-convex surface constituting the viewer-side surface of the optical member; an intermediate member disposed The surface side of the above-mentioned anti-glare film that is opposite to the above-mentioned concave-convex surface; and the light-diffusing film, which is arranged on the side of the above-mentioned display panel than the above-mentioned intermediate member; the above-mentioned anti-glare film has a light-transmitting substrate, and an anti-glare layer disposed on one side of the translucent substrate and having the concave-convex surface; the intermediate member is the front panel with a thickness of 0.5 mm to 5 mm. The optical member according to claim 1, wherein the above-mentioned front panel is a glass plate. A display device characterized by comprising: a display panel including a display element; and the optical member according to claim 1, which is arranged on the viewer's side relative to the display panel. A display device characterized by comprising: a display panel including a display element; an anti-glare film disposed on the viewer side of the display panel and having a concave-convex surface constituting the surface of the display device on the viewer side; an intermediate member , which is arranged between the above-mentioned display panel and the above-mentioned anti-glare film; and a light diffusion film, which is arranged between the above-mentioned display panel and the above-mentioned anti-glare film, and is arranged on the side of the above-mentioned display panel than the above-mentioned intermediate member; the above-mentioned display The distance between an element and the said light-diffusion film is 1 mm or less; The said intermediate member has a front panel or a touch panel. A display device, characterized by comprising: a display panel including a display element; An anti-glare film disposed on the viewer side of the display panel and having a concave-convex surface constituting the viewer-side surface of the display device; an intermediate member disposed between the display panel and the anti-glare film; and a light A diffusion film disposed between the display panel and the anti-glare film, and disposed closer to the display panel than the intermediate member; the distance between the display element and the light diffusion film is 1 mm or less; the intermediate member The thickness is not less than 0.1 mm and not more than 5 mm. The display device according to claim 4 or 5, wherein the display device is a vehicle-mounted display device.

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