WO2013035656A1 - 画像表示装置用防眩シートとその製造方法、及び、これを用いた動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れの改善方法 - Google Patents
画像表示装置用防眩シートとその製造方法、及び、これを用いた動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れの改善方法 Download PDFInfo
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- WO2013035656A1 WO2013035656A1 PCT/JP2012/072305 JP2012072305W WO2013035656A1 WO 2013035656 A1 WO2013035656 A1 WO 2013035656A1 JP 2012072305 W JP2012072305 W JP 2012072305W WO 2013035656 A1 WO2013035656 A1 WO 2013035656A1
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- antiglare
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/11—Anti-reflection coatings
- G02B1/113—Anti-reflection coatings using inorganic layer materials only
- G02B1/115—Multilayers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/16—Optical coatings produced by application to, or surface treatment of, optical elements having an anti-static effect, e.g. electrically conducting coatings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
- G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
- G02B5/0221—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having an irregular structure
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
- G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
- G02B5/0226—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures having particles on the surface
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133502—Antiglare, refractive index matching layers
Definitions
- the present invention provides an antiglare sheet for an image display device which is excellent in antiglare properties for use in blackness, darkness of darkness, and moving images, and suitable for realizing high image quality, a method for producing the same, and the antiglare sheet.
- the present invention relates to a method for improving blackness and image cutout of an image display device suitable for sharing a used moving image and still image.
- an optical laminate for preventing reflection is generally provided on the outermost surface. It has been.
- Such an anti-reflection optical laminate suppresses reflection of an image or reduces reflectivity by light diffusion or interference.
- an antiglare film in which an antiglare layer having an uneven shape is formed on the surface of a transparent substrate.
- This anti-glare film can prevent external light from diffusing due to the uneven shape of the surface, thereby preventing a decrease in visibility due to reflection of external light or reflection of an image.
- a film in which an anti-glare layer is formed by coating a resin containing a filler such as silicon dioxide (silica) on the surface of a transparent substrate film is known (for example, (See Patent Documents 1 and 2).
- These antiglare films are a type that forms an uneven shape on the surface of the antiglare layer by agglomeration of particles such as cohesive silica, a type that forms an uneven shape on the layer surface by adding an organic filler to the resin, or There is a type in which an uneven shape is transferred by laminating a film having unevenness on the layer surface.
- Such conventional anti-glare films are designed to obtain light diffusion / anti-glare action by the action of the surface shape of the anti-glare layer. Although it is necessary to make it large, there is a problem that when the unevenness becomes large, the haze value (haze value) of the coating film increases and white browning occurs, resulting in a decrease in contrast. Also, at home, the opportunity to appreciate a display that displays a high image quality such as a movie has increased, so the blackness of a black screen in a dark room (hereinafter referred to as darkness in the dark) is required.
- haze expressed by surface irregularities is “surface haze”, and is expressed when the surface irregularities are smoothed using a resin that forms the surface irregularities or a resin that has a refractive index difference of at least 0.02 or less.
- the haze to be defined is defined as “internal haze” and measured according to JIS K 7136.
- a haze value or a ratio of internal haze to total haze has been generally used. That is, in the process of manufacturing an optical sheet, it has been considered that an optical sheet with little reduction in contrast can be manufactured by controlling the material specification, manufacturing conditions, etc. so as to control the haze value (Patent Documents 1 to 6). 3).
- the contrast may be different.
- the haze value and the ratio between the internal haze and the total haze are used as an index, a good antiglare sheet for an image display device is not necessarily stable. Can't get to.
- Patent Documents 4 and 5 which show examples of different requirements depending on the viewing environment, describe that the required performance differs between the still image and the moving image, and the viewing state of the observer also differs.
- the present inventors did not simply add the total of internal diffusion and surface diffusion to the total haze as previously considered, but the total haze is other than internal diffusion and surface diffusion. It was also found that it is influenced by the positional relationship between the diffusing particles and the surface irregularities.
- a liquid crystal display device suitable for sharing a high blackness and high-quality moving image and still image in a dark room and a light room, for example, a liquid crystal display device (hereinafter simply referred to as a liquid crystal display device).
- stray light component refers to light that has entered the anti-glare sheet and travels in a direction different from the intended direction inside the anti-glare sheet due to the diffusion elements present on the surface and / or inside of the anti-glare sheet.
- the above-mentioned stray light component is partly stray light due to the diffusion element of the optical sheet. It becomes a so-called flare that emits light and causes a decrease in contrast, in particular, a decrease in dark room contrast, as well as a lack of stereoscopic effect and a flat and poorly changing image.
- the stray light component is less affected when viewed from the front, and more strongly affected when viewed from an oblique direction.
- the performance required for such moving images has the contrast, three-dimensionality and dynamic feeling (for example, taking a young man's scene under the blue sky as an example, the black hair displayed on the screen has a smooth feeling.
- Patent Document 6 describes “blackness” and Patent Document 7 describes “glossy blackness”.
- the blackness when the power is turned on is the amount of blackness when the above-mentioned leakage light and external light reflection are combined, and the blackness when the power is turned off because there is no image light. It is black when there is only external light reflection.
- the blackness is strong in both external light and leaked light, and unlike the above-mentioned blackness, the stray light component is not taken into account, and is appropriately required.
- the specular reflection component is not taken into account, so that even if the contrast is high, the image is inferior in the teri and shine, there is no dynamic feeling, and the black feeling is not high.
- priority is given to enlarging the diffusion and enlarging the angle of view, so stray light components are likely to occur, and darkness in dark places tends to decrease.
- glossy blackness suppresses the diffusion of light other than the specular reflection component of light incident on the optical laminate from outside, and prevents the non-specular reflection light from reaching the observer's eyes.
- Reproducibility of black when displaying black on the display device that is, richness of black gradation expression, crossed Nicol polarizing plate or acrylic adhesive for optical film on the opposite side of the film surface of the optical laminate ( Products with a total light transmittance of 90% or more, a haze of 0.5% or less, and a film thickness of 10 to 55 ⁇ m, for example, MHM series: manufactured by Niei Engineering Co., Ltd., Hitachi Chemical Co., Ltd., trade name “L8010”, etc.) After being attached to a black acrylic plate via a sensor, sensory evaluation is performed under three-wavelength fluorescence.
- Contrast is the ratio of white luminance to black luminance. Since the absolute value of black luminance is much smaller than white luminance, contrast is more strongly affected by black luminance. In order to obtain an image with excellent contrast, the blackness of “black spots” after increasing the angle of view, “darkness blackness” of absolute blackness, and gradation expression in black areas It is necessary that the “rich luster” that is richness is excellent (hereinafter referred to as being excellent in black reproducibility). Furthermore, in order to achieve a balance between a still image and a moving image, it is necessary to have at least excellent blackness with a three-dimensional effect and a dynamic feeling.
- Patent Documents 8 and 9 which limit the diffusion characteristics of the antiglare sheet, although the contrast is good, physical performance such as adhesion and hard coat properties, which are inevitable for practical use, glare, moving images and still images Problems such as compatibility were not taken into account, and sufficient performance was not obtained.
- JP 2002-267818 A JP2007-334294A JP2007-17626 JP2006-81089A JP 2006-189658 A JP2007-264113A JP2008-32845 JP2010-60924 JP 2010-60925
- the present invention is excellent in high-quality blackness, blackness, and black luster in a dark place without using a low-refractive interference layer.
- Anti-glare sheet for image display devices such as cathode ray tube display (CRT), liquid crystal display (LCD), plasma display (PDP), electroluminescence display (ELD), etc.
- CTR cathode ray tube display
- LCD liquid crystal display
- PDP plasma display
- ELD electroluminescence display
- the present invention provides an anti-glare sheet for an image display device that is excellent in anti-glare properties for use in blackness, darkness of darkness, and moving images, and is suitable for realizing high image quality, a method for manufacturing the same, and a method for producing the same. It is an object of the present invention to provide a method for improving the blackness of an image display device and image cutout suitable for sharing a moving image and a still image.
- liquid crystal televisions are regarded as defects from the viewpoint of an alternative to CRT, which has a narrow angle of view and isotropic properties, and antiglare films have been desired to have a function of widening the angle of view.
- the present inventors regard the liquid crystal television as a new display, consider the change in viewing environment, and do not regard the narrow angle of view and lack of isotropy as a defect. The following measures were taken to free the trade-off between the angle of view and the image quality.
- contrast and anti-glare properties have been calculated based on JIS B-0601-1994 arithmetic average roughness (Ra), ten-point average roughness (Rz), average interval between surface irregularities (Sm), and Kosaka Laboratory. It is considered that it depends on the surface shape such as the average inclination angle ( ⁇ a) of unevenness according to the definition described in the instruction manual (revised 1995.07.20) of the manufactured surface roughness measuring instrument SE-3400, or internal diffusion It was thought to depend on the reflection state of external light due to the difference in refractive index between the agent and the translucent resin, the shape of the internal diffusion particles, and the like. That is, the mutual effect between the surface unevenness and the internal diffusion element was not considered.
- ⁇ a tan ⁇ 1 [(h1 + h2 + h3 + h4 +... + hn) / L]
- the present inventors transmit the image light incident on the diffusion particles and the diffusion particles of the external light through the difference in refractive index between the internal diffusion particles and the translucent resin.
- the diffusion characteristics of light and reflected light are greatly different.
- the greater the difference in the refractive index between the diffusing particles and the translucent resin the greater the amount of light reflected by the diffusing particles, and the larger the diffusion angle of the light transmitted through the diffusing particles.
- the diffusing particle 2-2 in FIG. 7-2 when there is a positional relationship between the surface irregularity and the diffusing particle in which the diffusion of external light reflected by the diffusing particle is large, the 1- 1 in FIG. As shown in FIG. 2, the image light is also highly diffused and a stray light component is likely to be generated, and the contrast is easily lowered due to the image light. That is, the magnitude relationship of the contrast reduction due to the stray light component of the image light can be considered by approximating the reflection characteristic of the external light. The same applies to the blackness due to the stray light component.
- the present inventors have a directivity of video light from the inside because the anti-glare sheet for liquid crystal display devices has a small transmission diffusion and a moderately high transmission intensity. It has been found that the higher the state is, the better the smaller the stray light component of outside light and image light. On the other hand, if the transmission diffusion is large, stray light components are generated, the directivity of the internal image light is reduced, and the image looks like a whitish color, so that the display is not vibrant with respect to the display such as skin color.
- the cause of the difficulty in reflection for the observer is that the observer's focus is reflected on the outermost surface of the image display device when viewing the image. It has been found that this is because it often matches an image of the viewer (for example, an image of the observer himself or an image in which an object existing in the background is reflected), and the viewpoint cannot be determined in the original image.
- the outline of some external image that is reflected is blurred, so that the reflection does not become difficult and the decrease in contrast can be suppressed, improving the cutout of the image. I found out that it is possible.
- the video anti-glare property is a weak anti-reflection property that is limited to the time of watching a movie. As long as it is not limited, it is only necessary to satisfy the anti-glare property without satisfying the cutout of the image.
- antiglare sheets are often added with conductive particles to provide an antistatic function, and fine particles are added to prevent glare and surface unevenness. It has internal diffusion other than (diffusion).
- FIG. 1 shows, as an example, a simulation result of the surface reflectance of a resin coating film having a refractive index of 1.50 and the reflectance of a spherical diffusing agent particle surface dispersed in the resin coating film by changing the refractive index of the particles. is there.
- the surface diffusion is dominant in the diffuse reflection intensity.
- n ⁇ sin ⁇ sin ⁇ from Snell's law, where ⁇ is the exit angle from the inclined surface ⁇ and n is the refractive index of the coating film, and the exit angle ⁇ is arcsin. (N ⁇ sin ⁇ ) ⁇ .
- the reflection shows twice the change of the inclined surface ⁇ according to the law of reflection, so the reflection angle ⁇ is 2 ⁇ ⁇ . Therefore, within the range of the refractive index of a general coating film and the surface shape of an antiglare sheet, as shown in FIG. 2 which is a calculation result in the case of a resin surface with a refractive index of 1.50, It can be considered that the diffusion angle of transmission is proportional.
- the above (a) to (c) are respectively (a) small transmission diffusion (high regular transmission intensity), (b ′) small regular transmission intensity component, and (c ′) near the regular transmission. In other words, it can be translated into diffusion.
- the haze value that has been used for the anti-glare sheet for liquid crystal display devices so far is the ratio of the light diffused by 2.5 degrees or more from the regular transmission with respect to the total light as shown in JIS K7136. From the values, it is impossible to come up with the idea using diffusion in the vicinity of regular transmission as described above (particularly, diffusion less than 2.5 degrees).
- an antiglare sheet for a liquid crystal display device having no internal diffusion cannot suppress glare, so it is necessary to have even a slight internal diffusion.
- the amount of diffusion by internal diffusion may be diffusion that does not exceed 2.5 degrees. In this case, the haze due to internal diffusion is zero.
- the reduction rate of the diffuse transmission intensity is closer to 0 degrees. Since it is large, the closer to 0 degrees, the greater the decrease in strength, resulting in a liquid crystal display device antiglare sheet having a diffuse transmission intensity distribution of c.
- the intensity distribution of the diffusion characteristics is the diffusion intensity distribution by the diffusion element and the normal transmission without the diffusion element. It is the sum of two intensity distributions with only intensity.
- U is the diffusion characteristic of the diffusion element.
- the normal transmission intensity is approximated, and Q / U is the ratio of “part Q having no diffusing element” and “normal transmission intensity U of the diffusing element part”, that is, “intensity Q transmitted normally without transmission diffusion Q ”And“ regular transmission intensity U guided in the 0 degree direction by transmission diffusion ”, which is a measure of the diffusion state in the vicinity of the normal transmission.
- Q / U is approximated to the ratio of the flat part that becomes normal transmission and the uneven part that has an angle other than normal transmission with respect to the surface shape (external diffusion element).
- the refractive index difference between the diffusing particle and the translucent resin, the collision probability and shape of the diffusing particle, and the interaction between the surface shape and internal diffusion are In relation to the degree of weakening and the degree of strengthening, the blackness and sharpness are determined.
- the reflection ratio on the uneven surface can be expressed by the above Rp and Rs, which can be expressed as a function of the transmission diffusion angle ⁇ . And as Rp and Rs are larger, the amount of light reflected from the uneven surface and returning to the inside of the antiglare layer increases, so that the stray light component increases.
- FIG. 6 shows a result of calculating the above formula using a refractive index of 1.50 of a general translucent resin. Since the surface irregularities of the antiglare layer are randomly formed, the average reflection ratio can be expressed as (Rp + Rs) / 2. As is apparent from FIG. 6, when the transmission diffusion angle exceeds 30 degrees, the reflection increases rapidly, that is, the stray light component increases rapidly. Therefore, in order not to generate the stray light component, it is preferable that there is no transmission diffusion of 30 degrees or more. Since reflection starts to increase from 20 degrees, the generation of stray light components is ensured by setting the transmission diffusion to 20 degrees or less. Can be prevented.
- flexible diffusing particles are particles with a low degree of polymerization and a low crosslinking density, so that they easily swell in the coating solution for the antiglare layer, change in viscosity and gel, and have no coating stability and practical use. It was something that could not be subjected to.
- one feature is that attention is paid to Q / U.
- Log 10 Q 30 / Q
- the problem can be reliably solved and further improved.
- the object of the present invention can be achieved by any combination with other parameters, that is, various parameters as defined in the claims.
- the present invention compensates for the deficiencies due to the flexibility of the diffusing particles, and the diffusing particles whose resistance to shrinkage of the coating stability and translucent resin is in an appropriate range are impregnated on the surface of the diffusing particles.
- the inventors have found that the layer may be 5 to 40% of the radius of the diffusing particles, and have arrived at the present invention.
- the refractive index of the impregnated layer is closer to the refractive index of the translucent resin than the refractive index of the diffusing particles. Therefore, even if the above effect is obtained when impregnating 40% or more, the translucent resin and the diffusing particles Since the internal diffusion expressed by the difference from the refractive index is reduced, there is a possibility that the darkening property, in particular, the glare prevention property may be impaired.
- At least one surface of the transparent substrate has an antiglare layer containing a translucent resin and diffusion particles, and the antiglare layer has irregularities on the surface opposite to the transparent substrate,
- the unevenness is an antiglare sheet formed by convex portions based on the diffusion particles having an impregnation layer impregnated mainly with all or part of the components constituting the translucent resin, and the antiglare sheet
- the luminance in the normal transmission direction when irradiated with visible light vertically from the transparent substrate side is Q
- the luminance in the direction of 30 degrees from normal transmission is Q 30
- the luminance in the direction of +2 degrees from normal transmission and +1 degree from normal transmission The average value of the transmission intensities obtained by extrapolating the straight line connecting the luminance in the direction of normal and the straight line connecting the luminance in the direction of -2 degrees from the normal transmission and the luminance in the direction of -1 degree from the normal transmission to the normal transmission, respectively.
- An antiglare sheet characterized by satisfying the following (formula 1) and (formula 2) when U is defined.
- the thickness of the antiglare layer is T
- the radius of the translucent particles in the antiglare layer is R
- the thickness of the impregnation layer is P
- the following (Formula 3) and (Formula 4) Anti-glare sheet.
- At least one surface of the transparent substrate has an antiglare layer containing a translucent resin and diffusing particles, and the antiglare layer has irregularities on the surface opposite to the transparent substrate,
- the unevenness is an antiglare sheet formed by convex portions based on the diffusion particles having an impregnation layer impregnated mainly with all or part of the components constituting the translucent resin, and the antiglare sheet
- the luminance in the normal transmission direction when irradiated with visible light vertically from the transparent substrate side is Q
- the luminance in the direction of 30 degrees from normal transmission is Q 30
- the luminance in the direction of +2 degrees from normal transmission and +1 degree from normal transmission The average value of the transmission intensities obtained by extrapolating the straight line connecting the luminance in the direction of normal and the straight line connecting the luminance in the direction of -2 degrees from the normal transmission and the luminance in the direction of -1 degree from the normal transmission to the normal transmission, respectively.
- the present invention has excellent darkness, blackness and black luster in a dark place, has an antiglare property (moving image antiglare property) that is acceptable for moving images, and is suitable for practical use.
- An antiglare sheet for an image display device and a method for producing the same can be provided. Moreover, by using this anti-glare sheet, it is possible to provide a method for improving the blackness of the image display device and the cutout of the image suitable for sharing a moving image and a still image.
- the antiglare sheet of the present invention has an antiglare layer containing a translucent resin and diffusing particles on at least one surface of the transparent substrate, and the antiglare layer is on the surface opposite to the transparent substrate.
- the anti-glare sheet is formed by convex portions based on the diffusion particles having an impregnated layer impregnated mainly with all or part of the components constituting the translucent resin,
- the luminance in the normal transmission direction is Q
- the luminance in the direction from 30 ° from normal transmission is Q 30
- the luminance in the direction from + 2 ° from normal transmission is Transmission obtained by extrapolating the straight line connecting the luminance in the direction of +1 degree from the normal transmission and the straight line connecting the luminance in the direction of -2 degree from the normal transmission and the luminance in the direction of -1 degree from the normal transmission to the normal transmission.
- Antiglare characterized by satisfying the following (Equation 1) and (Equation 2) when the average value of strength is U: It is a sheet. (Formula 1) 10 ⁇ Q / U ⁇ 36 (Formula 2) Log 10 (Q 30 / Q) ⁇ 6
- FIG. 5 illustrating a method for measuring the Q and Q 30.
- transmission intensities at normal transmission ⁇ 2 degrees and normal transmission ⁇ 1 degrees are measured, the intensity is connected by a straight line, and an average of transmission intensity extrapolated to normal transmission (0 degree) is defined as a virtual normal transmission intensity U. Define (see FIG. 4).
- the measurement of diffuse transmission intensity is specifically measured as follows.
- Visible light is irradiated vertically from the back surface of the antiglare sheet (the surface opposite to the viewer side of the antiglare sheet).
- the light flux is incident on the antiglare sheet, and the diffuse transmission intensity is measured by scanning the light receiver at once in the range of ⁇ 85 degrees to +85 degrees with the diffusely transmitted light.
- the apparatus which measures diffuse transmission intensity In this invention, Nippon Denshoku Industries Co., Ltd. product "GC5000L” was used. In this measurement, the range between ⁇ 85 degrees and +85 degrees was measured. However, by performing measurements only at ⁇ 1, ⁇ 2, 0, +1, and +2 degrees, it is possible to easily calculate the virtual forward transmission intensity. Since the normal transmission intensity can be measured, it is easy to automatically adjust within the specified range while changing the manufacturing conditions online.
- the diameter of the light beam of “GC5000L” is about 3 mm, and this diameter is the average light beam diameter of a commonly used goniophotometer.
- the particle diameter of the translucent particles used in the present invention is on the order of microns, and the diameter of the light flux is about 1000 times larger than the diameter of the particles that are internal diffusion elements.
- the diameter of the light beam is sufficiently larger than the particle diameter, and the particles are evenly dispersed. Accurate measurement is possible without any significant difference.
- the Q 30 and Q 20 which is the transmission intensity in the direction of 20 degrees from the normal transmission are the average values of 20 degrees and ⁇ 20 degrees measured by the above measuring method, and the average values of Q 20 , 30 degrees and ⁇ 30 degrees. the value and Q 30.
- the present invention is characterized by controlling the following formula (x) as an index.
- Log 10 (Q 30 / Q) ⁇ 6 (x) By making Log 10 (Q 30 / Q) less than ⁇ 6, an antiglare sheet for a liquid crystal display device excellent in blackness and dark room blackness can be obtained. Furthermore, the anti-glare sheet
- the present invention is also characterized by controlling using the following formula (z) as an index. 10 ⁇ Q / U ⁇ 36 (z)
- Q / U By setting Q / U to be greater than 10, it is possible to obtain an antiglare sheet for a liquid crystal display device that is excellent in blackness and less than 36 by being excellent in moving picture antiglare property.
- Q / U is more than 11.5 and less than 34, since the blackness and the anti-glare property of moving images are further improved.
- the antiglare sheet for a liquid crystal display device of the present invention satisfies the above formulas (x) and (z).
- the antiglare sheet for a liquid crystal display device satisfying the above formulas (x) and (z) is excellent in high darkness, blackness, and black luster in a dark place, and has an antiglare property that is acceptable for use in moving images. It becomes an antiglare sheet for liquid crystal display devices having dazzling properties.
- the antiglare layer is a radiation curable translucent material that includes organic fine particles that are diffusion particles, and a (meth) acrylate monomer that is a translucent resin impregnating the organic fine particles.
- a coating liquid containing a resin preferably further containing a solvent that swells organic fine particles, more preferably a coating liquid having impregnation properties on the transparent substrate, and even more preferably a solvent that further swells the transparent substrate.
- the coating liquid contained is applied onto at least one surface of a transparent substrate, dried to form a coating film, and the coating film is cured.
- the organic fine particles that are diffusing particles have an impregnation layer impregnated with the radiation curable translucent resin that is a translucent resin.
- organic fine particles (A1) the organic fine particles before the impregnation layer is formed
- organic fine particles on which the impregnation layer is formed that is, the organic fine particles in the diffusion layer
- fine particles (A2) the organic fine particles on which the impregnation layer is formed
- the organic fine particles (A2) have extremely excellent adhesion to the cured product of the radiation curable translucent resin (hereinafter also referred to as translucent resin) of the diffusion layer.
- the impregnation layer in the organic fine particles (A2) is formed in a state where the radiation curable translucent resin and the material constituting the organic fine particles (A2) are mixed. Can be suitably prevented from being reflected at the interface between the organic fine particles (A2) (impregnated layer) and the translucent resin.
- the impregnating layer is a layer that is preferably formed by swelling the organic fine particles (A1) with the radiation curable translucent resin and / or the solvent that is a translucent resin
- (A2) is a very flexible fine particle.
- convex portions are formed on the surface of the diffusion layer at positions corresponding to the organic fine particles (A2) in the diffusion layer, but the shape of the convex portions can be made gentle. This point will be described in more detail later.
- the transparent base material has flexibility at the time of curing. By deforming, the convex part on the surface of the diffusion layer can be made smoother.
- the material constituting the organic fine particles (A1) those which are swollen by a radiation curable translucent resin and / or a solvent, which will be described later, are preferable.
- a polyester resin, a styrene resin, an acrylic resin examples thereof include olefin resins, copolymers thereof, and the like.
- a crosslinked acrylic resin and a crosslinked acrylic-styrene copolymer resin are preferably used.
- resin is a concept including resin components such as monomers and oligomers.
- an acrylic-styrene copolymer resin may be used as a material.
- the organic fine particles (A1) are core-shell type fine particles, there are polystyrene fine particles using fine particles made of acrylic resin for the core, and conversely polyacryl fine particles using fine particles made of styrene resin for the core. .
- the distinction between the acrylic fine particles, the styrene fine particles, and the acrylic-styrene copolymer fine particles is determined based on which resin has the closest characteristic (for example, refractive index) to the fine particles. .
- refractive index of the fine particles is less than 1.50, acrylic fine particles are obtained, and if the refractive index of the fine particles is 1.50 or more and less than 1.59, acrylic-styrene copolymer fine particles are obtained, and the refractive index of the fine particles is 1. If it is 59 or more, it can be regarded as styrene fine particles.
- cross-linked acrylic resin examples include acrylic monomers such as acrylic acid and acrylic acid ester, methacrylic acid and methacrylic acid ester, acrylamide and acrylonitrile, a polymerization initiator such as persulfuric acid, and a cross-linking agent such as ethylene glycol dimethacrylate.
- acrylic monomers such as acrylic acid and acrylic acid ester, methacrylic acid and methacrylic acid ester, acrylamide and acrylonitrile
- a polymerization initiator such as persulfuric acid
- a cross-linking agent such as ethylene glycol dimethacrylate.
- a homopolymer or a copolymer obtained by polymerization using a suspension polymerization method or the like is preferable.
- acrylic monomer a cross-linked acrylic resin obtained using methyl methacrylate is particularly suitable.
- the thickness of the impregnation layer can be controlled by adjusting the degree of swelling with the radiation curable translucent resin and / or solvent described later.
- the amount of impregnation of the radiation curable translucent resin It is preferable to change the degree of cross-linking so that is within a preferable range.
- the average particle size of the organic fine particles (A1) is preferably in the range of 0.5 to 10.0 ⁇ m, for example. In particular, the range of 1.0 to 8.0 ⁇ m is more preferable. If the particle size is less than 0.5 ⁇ m, the anti-glare property of the anti-glare film of the present invention may be insufficient. If it exceeds 10.0 ⁇ m, the particles are too large for the coating film. Smooth surface irregularities may not be possible. Further, when the thickness T of the antiglare layer and the radius of the particle which is half the average particle diameter of the organic fine particles are R, 0.25 ⁇ R / T ⁇ 0.45 It is preferable to satisfy.
- the said average particle diameter means the particle diameter of the particle which each particle
- the said particle size can be mainly measured as a weight diameter (volume diameter) by the Coulter counter method. In addition to this method, measurement can also be performed by laser diffraction, electron microscope observation, or optical microscope observation.
- the smaller the variation in the particle size of the translucent particles the less the variation in the diffusion characteristics, and the easier the diffuse transmission intensity distribution design. More specifically, it is preferable that (d75 ⁇ d25) / MV is not more than 0.25, where MV is an average diameter by weight average, d25 is a cumulative 25% diameter, and d75 is a cumulative 75% diameter. More preferably, it is .20 or less.
- the cumulative 25% diameter refers to the particle diameter when counted from a particle having a small particle diameter in the particle size distribution and reaches 25% by weight.
- the cumulative 75% diameter is similarly counted to 75% by weight.
- a method for adjusting the particle size variation for example, it can be carried out by adjusting the conditions of the synthesis reaction, and classification after the synthesis reaction is also an effective means.
- particles having a desired distribution can be obtained by increasing the number of times or increasing the degree. It is preferable to use a method such as an air classification method, a centrifugal classification method, a sedimentation classification method, a filtration classification method, or an electrostatic classification method for classification.
- the translucent particles are organic fine particles, the organic fine particles having an impregnated layer in which the components in the coating liquid penetrate the organic fine particles may be different from the original particle size.
- the particle diameter in the layer having the diffusing element for example, it can be carried out by adjusting the conditions of the synthesis reaction, and classification
- the organic fine particles (A2) in the diffusion layer have an impregnation layer.
- the impregnated layer is a layer formed by impregnating the radiation curable translucent resin from the outer surface of the organic fine particles (A2) in the diffusion layer toward the center thereof.
- the impregnated layer is a layer formed by impregnating a low molecular weight component, that is, mainly a monomer, of the radiation curable translucent resin, and a polymer of the radiation curable translucent resin that is a high molecular component. That is, it is difficult to impregnate a polymer or oligomer.
- the monomers those having a weight average molecular weight of 1000 or less are preferable.
- it is easily impregnated and has a weight average molecular weight of 250 to 600 or less, such as trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate. , And modified products thereof.
- the weight average molecular weight of this invention is calculated
- the impregnated layer can be identified, for example, by observing a cross section of the organic fine particles (A2) in the diffusion layer by observing an electron microscope (preferably a transmission type such as TEM, STEM, etc.), and by impregnating the impregnated layer, May be easier to observe.
- the radiation curable translucent resin impregnated in the impregnation layer may be impregnated with all the constituent components, or may be impregnated with a part of the constituent components.
- the average particle size (B2) in the diffusion layer of the particles (B) is larger than the average particle size of the organic fine particles (A2). Small is preferable. This is because convex portions with high height are formed at positions corresponding to the fine particles (B) on the surface of the diffusion layer, and there is a possibility that white browning cannot be sufficiently suppressed.
- the particle (B) also has an impregnated layer from the viewpoint of more reliably preventing the formation of a high convex portion due to the particle (B).
- the thickness of the impregnated layer of the organic fine particles (A) is P ( ⁇ m) and the radius of the organic fine particles is R ( ⁇ m)
- the following formula is preferably satisfied. 5% ⁇ P / R ⁇ 40% If it is 5% or less, the effect obtained by forming the impregnated layer described above cannot be sufficiently obtained, and if it is 40% or more, the formation of convex portions on the surface of the anti-glare layer becomes insufficient, and moving image anti-glare In addition to the inferior properties, the internal diffusion function of the organic fine particles (A2) is not sufficiently exhibited, and the glare prevention effect cannot be sufficiently obtained.
- the P / R is the average value of the thickness of the impregnated layer in the cross section of the organic fine particles (A) observed in the cross-sectional electron micrograph of the antiglare sheet, and the average radius based on the electron micrograph of the organic fine particles. Means the value divided by the value.
- the cross section of the diffusion layer is 3000 to 50,000 times with an electron microscope (transmission type such as TEM, STEM, etc.), and any 5 particles having an impregnated layer are always present.
- the thickness of the impregnated layer is measured at two points for each fine particle, and the measured value can be obtained as an average value.
- the thickness of the impregnated layer is measured by selecting two points where the boundary between the translucent resin around the fine particles and the fine particles is relatively clear and the maximum impregnation is performed.
- the organic fine particles that are diffusion particles generally have a crosslinked structure, but the degree of swelling by the radiation-curable translucent resin or solvent varies depending on the degree of crosslinking, and the degree of crosslinking is usually low. When it is high, the degree of swelling is low, and when the degree of crosslinking is low, the degree of swelling is high. Therefore, for example, when the material constituting the organic fine particles (A2) is the above-mentioned crosslinked acrylic resin, the thickness of the impregnated layer can be set to a desired range by appropriately adjusting the degree of crosslinking of the crosslinked acrylic resin. Can be controlled.
- an antiglare sheet is prepared in advance with a coating solution using organic fine particles having different crosslinking degrees, and the organic fine particles conform to a preferable degree of impregnation. Can be selected and used.
- Fine particles are immersed in the obtained coating liquid, immediately after that, placed on a slide glass with a dropper, and a cover glass is further placed thereon. This was observed with an optical microscope, and the average particle diameter d 0 (average value of 20 fine particles) was determined. Further similarly that after 24 hours after immersion were observed with an optical microscope to obtain an average particle diameter d 24. Fine particles having a particle size change rate ((d 24 -d 0 ) / d 0 ) of 5% or more are defined as “low cross-linking”, and fine particles having a particle size less than 5% are defined as “high cross-linking”.
- the content of the organic fine particles (A1) in the coating liquid is not particularly limited, but is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the radiation curable translucent resin described later. If the amount is less than 0.5 parts by mass, a sufficient uneven shape cannot be formed on the surface of the diffusion layer, and the antiglare performance of the antiglare sheet of the present invention may be insufficient. On the other hand, when the amount exceeds 30 parts by mass, the organic fine particles (A1) are aggregated in the coating liquid, a large convex portion is formed on the surface of the diffusion layer, and the desired performance cannot be obtained. May occur.
- the minimum with more preferable content of the said organic fine particle (A1) is 1.0 mass part, and a more preferable upper limit is 20 mass parts. By being in this range, the above-mentioned effect can be further ensured.
- the thickness T of the antiglare layer In addition to defining Q / U, Log 10 (Q 30 / Q), and Log 10 (Q 20 / Q), the thickness T of the antiglare layer, the total haze Ha of the antiglare sheet for liquid crystal display devices ( %), Haze Hi (%) generated by internal diffusion, diffusion due to surface unevenness (hereinafter sometimes referred to as external diffusion) and diffusion (Ha-Hi) as the sum of the interaction between the internal diffusion and diffusion (Ha-Hi)
- the performance of the antiglare sheet for a liquid crystal display device used on the surface of the liquid crystal display element can be further improved by selecting the relationship, the combination of the light transmissive resin of the diffusion layer, the transparent base resin, and the like. .
- ⁇ Glitter cannot be resolved if the internal diffusion is small. However, since it is counted as the haze Hi generated by internal diffusion when internal diffusion having a diffusion angle of 2.5 degrees or more exists, it is necessary to have appropriate internal diffusion even if Hi is zero. is there. However, diffusion with a large diffusion angle, that is, if the internal haze Hi counted as haze is too large, the resolution is lowered, and the darkness is reduced due to the generation of stray light components. Getting worse.
- the contrast is lowered, by setting the internal haze to 3.0 or more, the blackening property can be improved by the effect of expanding the angle of view.
- the total haze is not the sum of internal diffusion and surface diffusion as previously considered, but the total haze is not only the internal diffusion and the surface diffusion, but the knowledge that the positional relationship between both diffusion elements affects
- the basic idea is that the total haze is haze due to the interaction between internal haze + external haze + internal diffusion elements and surface irregularities. Therefore, when the haze of the antiglare sheet for liquid crystal display devices is Ha and the haze generated by internal diffusion is Hi, Ha-Hi can be said to be the sum of the haze and the external haze due to the interaction between the internal diffusion elements and the surface irregularities. it can.
- haze (Ha-Hi) tends to be low. Further, when the diffusion angle is less than 2.5 degrees, it is not counted as haze. Therefore, even if haze (Ha-Hi) is 0, which has been regarded as inappropriate, the Q / U value only needs to be in a desired range. More preferably, it is 0% or more and 4% or less, and still more preferably 0% or more and 2% or less.
- the difference in refractive index between the transparent resin constituting the antiglare layer and the diffusing particles is preferably 0.005 to 0.25.
- the difference in refractive index is preferably 0.01 to 0.2, and more preferably 0.015 to 0.15.
- the organic fine particles are organic fine particles having an impregnated layer in which the diffusion particles are organic fine particles and the components in the coating liquid penetrate into the organic fine particles, and the components in the coating liquid are not impregnated at the center of the organic fine particles.
- organic fine particles are used, so that the difference in refractive index at the interface between the organic fine particles and the translucent resin is reduced, so that reflection is suppressed so that stray light components are not easily generated, and the inside of the organic fine particles has a refractive index with the translucent resin. Since the difference is large, internal diffusion is maintained, which is more preferable because it is easy to achieve both prevention of generation of stray light components and prevention of glare.
- the crosslink density of the organic fine particles can be reduced, the impregnating solvent can be shared, the coating solution standing temperature can be increased, etc. It is important to select conditions that provide a preferable impregnation amount.
- P / R is preferably in the range of 5 to 40% from the viewpoint of the above-mentioned surface unevenness control, but from the viewpoint of maintaining the internal diffusion performance, the components in the coating liquid It is preferable that the center part which is not impregnated has a diameter of a visible light wavelength or more, and more preferably a diameter of 1 ⁇ m or more.
- the diameter of the non-impregnated portion of the central portion is specifically 3,000 to 50,000 times the cross section of the diffusion layer with an electron microscope (preferably a transmission type such as TEM, STEM, etc.). After observing and photographing any 5 scenes in which at least one fine particle always exists, measure the diameter of the unimpregnated portion of the central portion and obtain an average of 10 measured values. Can do. Further, the particle diameter and the thickness of the translucent resin existing on the upper part of the particle can also be obtained from an average value by observing and measuring in the same manner as described above by photographing a cross section passing through the vicinity of the particle center.
- the ratio D of the value of the optical comb of 2.0 mm to the optical comb of 0.125 mm in the transmitted image definition of the antiglare sheet based on JIS K7105 is preferably less than 2.
- the value at 0.125 mm of the optical comb represents the size of diffusion in the vicinity of regular transmission (the smaller the value, the larger the diffusion), which causes fine distortion of the image light, that is, glare.
- the value with the 2.0 mm optical comb represents the effect of making the diffusion in a wider range, i.e., the glare less noticeable, and the larger the value, the smaller the effect.
- the D is more preferably less than 1.9, and even more preferably less than 1.4.
- the refractive index of the translucent particles was measured by measuring the turbidity by dispersing an equal amount of the translucent particles in the solvent in which the refractive index was changed by changing the mixing ratio of two types of solvents having different refractive indexes.
- the refractive index of the solvent when the turbidity is minimized with an Abbe refractometer it is measured by a method such as using a Cargill reagent.
- these refractive indexes can be measured by actually removing particles or fragments of particles from the film after making an antiglare sheet for a liquid crystal display device, or by measuring the cut surface of the antiglare sheet with an ellipsometer. It can also be measured by a method of measuring by, a method of measuring laser interference of an antiglare sheet, or the like.
- the radiation-curable translucent resin that is a translucent resin contains a (meth) acrylate monomer as an essential component.
- a radiation curable translucent resin include those that swell the organic fine particles (A1) described above, and are preferably transparent.
- ionizing radiation curing that is cured by ultraviolet rays or electron beams. Mold resin.
- (meth) acrylate refers to methacrylate and acrylate.
- the monomer since the monomer is ionized radiation cured to form a polymer film, it includes all molecules that can be a structural unit of the basic structure of the polymer film and has an unsaturated bond.
- the oligomer or prepolymer is a basic unit of a cured film, the oligomer or prepolymer is also included.
- the low molecular weight monomer having impregnation property preferably has a weight average molecular weight of 1000 or less, and more preferably 250 to 600.
- the functional groups of the monomer, oligomer and prepolymer those having ionizing radiation polymerization are preferable, and among them, a photopolymerizable functional group is preferable.
- the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group.
- the prepolymer and oligomer include acrylates such as urethane (meth) acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate, unsaturated polyester, and epoxy resin.
- Monomers include styrene monomers such as styrene and ⁇ -methylstyrene; methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, pentaerythritol (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol Tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) Acrylate, glycerin propoxytriacrylate, ditrimethylolpropane tetraacrylate, polyethylene glycol di (meth) acrylate, bis Eno
- a polyfunctional acrylate is preferable, and among them, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate are more preferable. preferable.
- a polymer to the resin composition as a translucent resin.
- the polymer include polymethyl methacrylate (PMMA) and cellulose acetate propionate (CAP).
- the preferred weight average molecular weight of the polymer is 20,000 to 100,000. In order to adjust the viscosity to be less than 20,000, it is necessary to increase the amount of addition, and the hardness of the antiglare layer may be lowered. If it is 100,000 or more, the viscosity is too high and the coating property is lowered. This is because there is a risk that the hardness may be reduced due to cross-linking inhibition during the curing reaction if a compound having an excessively large weight average molecular weight is present in the composition.
- the photopolymerization initiator can be added to the resin composition as necessary.
- the radical photopolymerization initiator acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds and the like are used.
- acetophenones 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxy-dimethylphenylketone, 1-hydroxy-dimethyl-p-isopropylphenylketone, 1-hydroxycyclohexylphenyl Ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 4-phenoxydichloroacetophenone, 4-t-butyl-
- benzoins include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ketal, and benzoin benzenesulfonic acid.
- Benzophenones include benzophenone, hydroxybenzophenone, 4benzoyl-4′-methyldiphenyl sulfide, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone, 4,4′-dimethylaminobenzophenone ( Michler's ketone), 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone and the like can be used.
- Photosensitizers can also be mixed and used, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine and the like.
- the resin along the fine particles at the time of curing.
- the polymerization shrinkage the shape of the fine particles largely reflects on the surface unevenness, and the uneven inclination angle may become large, but the inclination angle of the antiglare layer surface can be reduced by reducing the polymerization shrinkage at that time, the whole Therefore, it is possible to obtain a moderate external diffusivity.
- the internal diffusion can be controlled by adjusting the refractive index of the transparent resin by adding fine particles having a high refractive index or a low refractive index of 100 nm or less to the ionizing radiation curable resin or thermosetting resin. Is possible.
- organosilane when organosilane is contained in the translucent resin, the cohesiveness of the particles changes greatly due to the combination of the resin, solvent system, particle lipophilicity and hydrophilicity in the coating liquid, and the optical properties are stable. Therefore, it is preferable to avoid the use of organosilane. This is because even if one type of particle is used, for example, since composition variation occurs due to the difference in solvent volatility during drying (usually two or more types), it is difficult to control aggregation and dispersion. It is analogized that. This is particularly remarkable when two or more kinds of particles having different lipophilicity and hydrophilicity are used. For this reason, there is a possibility that control of roughness and glare cannot be performed due to the occurrence of steep unevenness.
- a solvent is usually used in the radiation curable resin composition in order to adjust the viscosity and to dissolve or disperse each component.
- a solvent is usually used in the radiation curable resin composition in order to adjust the viscosity and to dissolve or disperse each component.
- the thickness of the impregnated layer of organic fine particles differs depending on the type of solvent used, and that the surface state of the coating film varies depending on the coating and drying processes, so that the transmission intensity distribution due to external diffusion can be adjusted. Therefore, it is preferable to select appropriately. Specifically, it is selected in consideration of saturated vapor pressure, permeability to a transparent substrate, and the like.
- the thickness of the antiglare layer is controlled, and the surface of the substrate is impregnated by impregnating the transparent substrate.
- This technique is particularly effective when the transparent substrate is made of a cellulose resin.
- a solvent having impregnation properties for the particles at least a part of the components of the transparent resin can easily penetrate into the particles, and the above-described impregnation layer can be adjusted, which leads to control of the diffuse transmission strength.
- the radiation curable translucent resin which is a translucent resin, and the solvent may both be selected from those having the property of swelling the organic fine particles (A1), but only one of them may be used. Those having the property of swelling the organic fine particles (A1) may be selected and used.
- the formation of the impregnated layer of the organic fine particles (A1) is performed regardless of the degree of swelling of the radiation curable translucent resin because a solvent having a property of swelling the organic fine particles (A1) is present. Therefore, at least the solvent preferably contains a solvent having a property of swelling the organic fine particles (A1).
- the organic fine particles (A1) are first swelled by the solvent and the organic fine particles (A1) swell, and then the low molecular weight components contained in the radiation curable translucent resin are impregnated. I guess there is.
- the combination of the radiation curable translucent resin and the solvent among them, the radiation curable translucent resin has a small molecular weight and is easily impregnated.
- the solvent it is preferable to use a combination of a strong ketone and ester type which swell the organic fine particles (A1).
- the amount of impregnation of the low molecular weight component contained in the radiation curable translucent resin can be controlled.
- the solvent can be appropriately selected from the above viewpoints. Specifically, aromatic solvents such as toluene and xylene, and ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone are preferable. These may be used alone or in combination of two or more.
- aromatic solvents such as toluene and xylene
- ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone are preferable. These may be used alone or in combination of two or more.
- cellosolves such as methyl cellosolve and ethyl cellosolve and cellosolve acetates
- alcohols such as ethanol, isopropanol, butanol, and cyclohexanol may be mixed.
- additives other than the translucent particles are blended in the translucent resin, that is, the transparent resin, as necessary.
- various inorganic particles can be added to improve physical properties such as hardness, optical properties such as reflectance, and diffusivity.
- inorganic particles include metals such as zirconium, titanium, aluminum, indium, zinc, tin, and antimony, ZrO 2 , TiO 2 , Al 2 O 3 , In 2 O 3 , ZnO, SnO 2 , Sb 2 O 3 , ITO, Examples thereof include metal oxides such as ATO and SiO 2 .
- metals such as zirconium, titanium, aluminum, indium, zinc, tin, and antimony
- ZrO 2 TiO 2 , Al 2 O 3 , In 2 O 3 , ZnO, SnO 2 , Sb 2 O 3 , ITO
- metal oxides such as ATO and SiO 2 .
- carbon, MgF, silicon, BaSO 4 , CaCO 3 , talc, kaolin, smectite and the like are included.
- the particle size of the inorganic particles is preferably as fine as possible in the resin composition when applying the antiglare layer in order to reduce the influence on the diffuse transmission intensity distribution, and the average particle size is 100 nm. The following range is preferable.
- an antiglare sheet for a liquid crystal display device that does not impair transparency can be formed.
- the particle diameter of the inorganic particles can be measured by a light scattering method or an electron micrograph.
- various surfactants can be used to improve the properties such as anti-aggregation effect and anti-settling effect, and other leveling properties.
- the surfactant include silicone oil, a fluorine-based surfactant, and preferably a fluorine-based surfactant containing a perfluoroalkyl group.
- an antifouling agent an antistatic agent, a colorant (pigment, dye), a flame retardant, an ultraviolet absorber, an infrared absorber, an adhesion promoter, a polymerization inhibitor, an antioxidant, a surface modifier, etc.
- a colorant pigment, dye
- a flame retardant an ultraviolet absorber
- an infrared absorber an infrared absorber
- an adhesion promoter an adhesion promoter
- a polymerization inhibitor an antioxidant, a surface modifier, etc.
- seat for liquid crystal display devices of this invention if it is normally used for the anti-glare sheet
- a transparent resin film, a transparent resin board, a transparent resin sheet, and transparent glass there is no particular limitation.
- Transparent resin films include triacetylcellulose film (TAC film), diacetylcellulose film, acetylbutylcellulose film, acetylpropylcellulose film, cyclic polyolefin film, polyethylene terephthalate film, polyethersulfone film, polyacrylic resin film, polyurethane film Resin films, polyester films, polycarbonate films, polysulfone films, polyether films, polymethylpentene films, polyether ketone films, (meth) acrylonitrile films, polynorbornene resin films, and the like can be used.
- TAC film triacetylcellulose film
- diacetylcellulose film diacetylcellulose film
- acetylbutylcellulose film acetylpropylcellulose film
- cyclic polyolefin film polyethylene terephthalate film
- polyethersulfone film polyacrylic resin film
- polyurethane film Resin films polyester films, polycarbonate films, polysulf
- the TAC film is a cyclic polyolefin film because it does not disturb the polarization.
- a polyester film such as a polyethylene terephthalate film is preferable.
- the said transparent base material may be a multilayer, a single layer, and may provide a primer layer on the surface for the purpose of adhesiveness with a coating film.
- a coating solution that impregnates the transparent substrate may be used.
- An interference fringe prevention layer having an intermediate refractive index may be provided between the film layer and unevenness of about 0.3 to 1.5 ⁇ m may be provided as the surface roughness (10-point average roughness Rz). Is possible. Rz is a value measured based on a method based on JIS B0601 1994 with a cutoff value of 2.5 mm and an evaluation speed of 0.5 mm / s.
- the antiglare sheet for a liquid crystal display device can have functions such as hard coat property, antireflection, antireflection property, antistatic property and antifouling property.
- Hard coat properties are usually the maximum load at which scratches are not confirmed when a black tape is applied to the back side of a 10-reciprocal rubbing test while applying a load with pencil hardness (measured according to JIS K5400) or steel wool # 0000. (Steel wool scuff resistance)
- the pencil hardness is preferably H or higher, more preferably 2H or higher.
- the maximum load at which no scratch is confirmed even after 10 reciprocating rubbing tests is preferably 200 g / cm 2 or more, more preferably 500 g / cm 2 or more, and 700 g / cm 2. It is particularly preferable that it is cm 2 or more.
- antistatic performance in terms of preventing static electricity on the surface of the antiglare sheet for liquid crystal display devices.
- a method of applying a conductive coating liquid containing conductive fine particles, a conductive polymer, a quaternary ammonium salt, thiophene and a reactive curable resin, or a transparent film is formed.
- Conventionally known methods such as a method of forming a conductive thin film by vapor deposition or sputtering of metal, metal oxide or the like can be mentioned.
- the antistatic layer can be used as a part of a functional layer such as a hard coat, reflection resistance, and antireflection.
- the surface resistance value is preferably 10 12 ⁇ / ⁇ or less, more preferably 10 11 ⁇ / ⁇ or less, and particularly preferably 10 10 ⁇ / ⁇ or less.
- the so-called saturation band voltage which is the maximum voltage that can be stored in the optical film, is preferably 2 kV or less with an applied voltage of 10 kV.
- an antifouling layer can be provided on the outermost surface of the antiglare sheet for a liquid crystal display device of the present invention.
- the antifouling layer lowers the surface energy and makes it difficult to attach hydrophilic or lipophilic stains.
- the antifouling layer can be imparted by adding an antifouling agent, and examples of the antifouling agent include fluorine compounds, silicon compounds, and mixtures thereof, and compounds having a fluoroalkyl group are particularly preferred.
- stacked on the surface can be provided in the outermost surface of the anti-glare sheet
- the low refractive index layer is a layer having a thickness of about 0.1 ⁇ m, and reduces reflection of external light by interference.
- the low refractive index layer is not limited in any way, but it is preferable to form a coating liquid containing an ultraviolet curable resin to which porous or hollow silica is added by coating and curing. By applying and curing the coating liquid, the fine and sharp irregularities present on the convex portions on the surface of the antiglare layer are smoothed to become smoother, and in addition to the antireflection effect, the blackness can be further improved. Can be planned.
- the antiglare sheet for a liquid crystal display device of the present invention is produced by applying a resin composition constituting an antiglare layer having an uneven shape on the outermost surface to a transparent substrate.
- a resin composition constituting an antiglare layer having an uneven shape on the outermost surface is produced by applying a resin composition constituting an antiglare layer having an uneven shape on the outermost surface to a transparent substrate.
- Various methods can be used as the coating method, such as dip coating, air knife coating, curtain coating, roll coating, wire bar coating, gravure coating, die coating, blade coating, Known methods such as a micro gravure coating method, a spray coating method, a spin coating method, and a reverse coating method are used.
- the transmission diffusion luminance characteristic changes depending on the coating amount
- a roll which can easily stably obtain the sum of the thickness of the layer having the diffusion element therein and the transparent resin layer in the range of 3.0 to 10.0 ⁇ m.
- a coating method, a gravure coating method, a die coating method, and a reverse coating method are preferable.
- the coating liquid is preferably allowed to stand for a predetermined time before forming the diffusion layer.
- the degree of crosslinking of the organic fine particles (A) to be used the degree of crosslinking of the organic fine particles (A) with the radiation-curable translucent resin and / or solvent This is because even when the degree of swelling is appropriately adjusted, a sufficient impregnation layer may not be formed on the organic fine particles (A2) in the diffusion layer.
- the standing time of the coating liquid may be appropriately adjusted depending on the type of organic fine particles (A) used, the degree of crosslinking and the particle size, and the type of radiation curable translucent resin and / or solvent used. For example, it is preferably about 12 to 48 hours.
- a method of adjusting transmission diffusion luminance characteristics by selecting drying conditions is simple and preferable.
- the drying temperature is preferably 30 to 120 ° C.
- the drying wind speed is preferably 0.2 to 50 m / s, and the transmission diffusion luminance characteristic can be adjusted by appropriately adjusting within this range.
- the permeability of the resin and the solvent to the base material can be adjusted by controlling the type of solvent and the drying temperature. That is, when the solvent conditions are the same, the permeability of the resin and the solvent to the base material can be adjusted by controlling the drying temperature, and as described above, the surface unevenness shape is controlled.
- Measurement procedure (1) In order to obtain a clear image without halation, use a wet objective lens in a confocal laser microscope, and place about 2 ml of oil with a refractive index of 1.518 on the optical laminate. did. The use of oil was used to eliminate the air layer between the objective lens and the antiglare layer.
- Total haze Ha (%) measurement method
- the total haze value can be measured according to JIS K-7136.
- a haze meter HM-150 (Murakami Color Research Laboratory) was used as a measuring instrument. The haze is measured with the transparent substrate surface facing the light source.
- the antiglare sheet for liquid crystal display devices should be squeezed beforehand. Hydrophilic treatment is performed by chemical treatment (2 mol / l NaOH (or KOH) solution 55 ° C for 3 minutes, then washed with water, completely removed with Kimwipe etc., then dried in 50 ° C oven for 1 minute) Good.
- the sheet having a flat surface does not have surface irregularities and has no interaction, and therefore has only internal haze.
- the haze of this sheet can be measured as the total haze according to JIS K-7136 and determined as the internal haze.
- Moving image anti-glare property When displaying moving images, it is excellent in anti-reflection (state that the observer and the background of the observer are not concerned) and judged by whether or not the moving image can be seen. .
- the state where the observer and the background reflection of the observer are not concerned is that the observer is present, but only the outline is unclear and blurred, and the presence of objects in the background is also recognized However, the outline and boundary are unclear.
- the white wall in the background it is recognized that there is a white wall, but the white boundary is blurred and the boundary line of the wall is unclear. In this way, only the outline and the like are blurred, and the viewer is not concerned about the reflection.
- This anti-glare property is different from the conventional anti-glare property in which the observer and the background are not completely reflected and completely blurred and unclear.
- Glare Judgment was made based on whether or not glare was acceptable when displaying a still image. ⁇ : More than 10 people answered that glare is acceptable ⁇ : 5-9 people answered that glare is acceptable ⁇ : Less than 4 people answered that glare is not acceptable
- Black luster 45 degree in the state which put the material which bonded the glare-proof sheet for liquid crystal display devices on the black acrylic board using the said transparent adhesive film for optical films on a horizontal surface, and lit the three wavelength ray tube Fifteen test subjects perform visual sensory evaluation on the incident surface from the regular reflection direction and determine whether glossy black can be reproduced. ⁇ : More than 10 people answered good ⁇ : 5-9 people answered good ⁇ : Less than 4 people answered good
- Ratio D of the value of the optical comb 2.0 mm to the optical comb 0.125 mm in the transmitted image definition D Based on JIS K7105, the values of the optical combs 0.125 mm and 2.0 mm at the transmitted image definition of the antiglare sheet are obtained and the ratio is calculated.
- an image clarity measuring instrument ICM-1T Suga Test Instruments
- the antiglare films obtained in the examples and comparative examples were cut in the thickness direction of the diffusion layer, and a cross section containing at least one organic fine particle (A) as diffusion particles was magnified 3000 to Observed with a transmission electron microscope (STEM) at a magnification of 50,000 times, the organic fine particles (A) and the surrounding light-transmitting resins are the portions where the radiation-curable translucent resin is impregnated with the organic fine particles (A).
- the thickness of the two portions where the radiation curable translucent resin is most impregnated in the organic fine particles (A) is measured, and a total of five organic particles are measured.
- the fine particles (A) were measured in the same manner, and the average value of 10 measurement results was calculated.
- Example 1 Triacetyl cellulose (manufactured by Fuji Film Co., Ltd., thickness 80 ⁇ m) was prepared as a transparent substrate. Next, 60 parts by mass of pentaerythritol tetraacrylate (PETTA, product name: M-450, manufactured by Toa Gosei Co., Ltd.), dipentaerythritol hexaacrylate (DPHA) is used as a radiation curable translucent resin that is a translucent resin.
- PETTA pentaerythritol tetraacrylate
- DPHA dipentaerythritol hexaacrylate
- acrylic particles (refractive index: 1.49, average particle size: 5.0 ⁇ m) are 9.0 masses with respect to 100 mass parts of the radiation curable translucent resin.
- 190 parts by mass of a mixture of toluene and methyl isobutyl ketone (mass ratio 7: 3) as a solvent with respect to 100 parts by mass of the radiation-curable translucent resin, and a polymerization initiator Iraki A 184 (manufactured by BASF Japan) and leveling agent polyether-modified silicone (TSF4460, manufactured by Momentive Performance Materials) are each 5 parts by mass and 0.04 parts by mass with respect to 100 parts by mass of the radiation curable translucent resin.
- a coating solution was prepared by blending. The obtained coating liquid was allowed to stand for 24 hours, and then applied to a light-transmitting substrate using a Mayer bar, and dried at 70 ° C.
- the coating film was irradiated with ultraviolet rays (200 mJ / cm 2 under a nitrogen atmosphere) to cure the radiation curable translucent resin, to form a diffusion layer, and to produce an antiglare sheet.
- Examples 2 to 10 An antiglare film was produced in the same manner as in Example 1 except that each component added to the coating liquid and the conditions were as shown in Table 1.
- grains was 30% of the addition amount of particle
- the impregnation percentage of the particles (B) was performed according to the measurement of the particles (A).
- Table 1 shows the results of the antiglare sheets obtained in the examples and comparative examples.
- the antiglare sheet according to the example had excellent optical characteristics because an appropriate impregnation layer was formed on the organic fine particles (A) in the diffusion layer.
- the antiglare sheet for an image display device of the present invention it is possible to obtain an image display device that is excellent in darkness darkness and blackness and excellent in moving image antiglare property. And by using this anti-glare sheet, it is possible to improve the blackness of the image display device suitable for sharing the moving image and the still image and the cutout of the image.
Abstract
Description
これらの防眩性フィルムは、凝集性シリカ等の粒子の凝集によって防眩層の表面に凹凸形状を形成するタイプ、有機フィラーを樹脂中に添加して層表面に凹凸形状を形成するタイプ、あるいは層表面に凹凸をもったフィルムをラミネートして凹凸形状を転写するタイプ等がある。
また、家庭でも、映画等の高度な画質を表示したディスプレイを鑑賞する機会が増えたため、暗室での黒画面の黒さ(以下、暗所黒味という)が求められている。
なお、表面凹凸により発現するヘイズを「表面ヘイズ」、前記表面凹凸を、表面凹凸を形成する樹脂又は該樹脂との屈折率差が少なくとも0.02以内の樹脂を用いて平滑化したときに発現するヘイズを「内部ヘイズ」と定義し、JIS K 7136 に準拠して測定する。
例えば、映画鑑賞等をする機会の増加により、映画館並みの高度な視聴環境で楽しむために、暗室で動画像を高画質で再現することが要求されたり、モバイル用途の増加により、明るい屋外で静止画像及び動画像を映し出すために、物理的な強度を有し且つ明室で動画及び静止画のバランスの取れた画質が要求されている。
すなわち、ディスプレイ端末に要求される画像品質は変化しており、視聴環境に適した性能を有する画像表示装置用の防眩シートの開発が要望されている。
また、明室での動画像と静止画像に対しては映像光の迷光成分を考慮しつつ、これまでは防止することのみが求められていた外光の正反射成分を適度に持たせることが鑑賞に堪えうる画質を得るために重要であることを見出した。
なお、迷光成分は、正面から見た場合には影響が少なく、斜め方向から見た場合にはより強く影響が出やすい。
加えて、照明下で映画観賞をする場合や、モバイル用途では、動画像の鑑賞に際しても動画像の鑑賞に対応した耐映り込み性(防眩性)が求められている。そのような、完全に映り込みが無いわけではなく、動画を観測する観測者の輪郭や背景にある対象物の輪郭や境界線がぼやける程度の微弱な耐映り込み性を動画防眩性と称する。
すなわち、黒彩感と画像の切れに優れた液晶表示装置用防眩シートであるべきとの要望が高くなっている。
黒しまり性は、この画角拡大とコントラストの折り合いを評価するもので、ディスプレイを真正面から電源off時の黒味、電源on時の黒味(黒い画像)を比較し、黒味の強いほど画面のしまり感も強いという官能比較である。
正面では非常に弱く、斜めほど強く認知されやすくなる迷光成分以外に、液晶ディスプレイではそのシステム構成上、黒表示においても液晶表示素子そのものから漏れてくる光(漏れ光)が存在するので、真正面から見た電源on時の黒味とは、前述の漏れ光と外光反射とを合わせた場合の黒さの加減であり、前述の電源off時の黒味とは、映像光は存在しないから、外光反射のみがあるときの黒味である。
換言すれば、黒しまり性とは外光にも漏れ光にも黒味が強いことになり、前述の黒彩感とは異なり、迷光成分は考慮されておらず、また、適度に必要とされる正反射成分が考慮されていないため、喩えコントラストは高くとも画像のテリ及び輝きに劣り、躍動感は生じず、黒彩感は高くならない。ことに、拡散を大きくして画角を拡大することが優先されるので迷光成分が生じやすく、暗所黒味が低下しやすい。
すなわち、その測定法から見ても、動画の評価ではないし、映像光の迷光成分の影響も全く考慮されていない。そのため、喩えテリ及び輝きは高くとも、暗室コントラスト及び立体感は生じず、黒彩感は高くならない。
さらに、静止画と動画の両立を図るには、少なくとも立体感及び躍動感を有する黒彩感に優れていることが必要である。
なお、防眩シートの拡散特性を限定する特許文献8及び9では、コントラストは良好となるものの、実用に不可避な性能である密着性、ハードコート性等の物理性能やギラツキ、動画と静止画の両立等の課題は考慮されておらず、充分な性能を得られていなかった。
すなわち、本発明は、黒彩感、暗所黒味、動画用途で防眩性に優れ、高度な画質の実現に適した画像表示装置用の防眩シートとその製造方法、及び、これを用いた動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れの改善方法を提供することを目的とする。
然るに、本発明者らは液晶テレビを新たなディスプレイと捉えると共に、視聴環境の変化を勘案し、画角が狭く等方性が無いことを欠陥として捉えることなく、正面画質優先の思想のもと、画角と画質のトレードオフの呪縛から開放されるべく、以下の手段を講じた。
ここで、θaの算出定義を説明する。
基準長さL範囲内に存在する凹凸形状において、ひとつの山から次の山へ至るまで、山には、一番高い頂部:凸部があり、かつその両端には、凹部が存在している。凹部の位置は、それぞれ同じ高さにあるとは限らない。
この異なる凹部位置各々から、その三角形の頂部までの高さをh1、h2とする。同じように、基準長さ範囲の全ての山について、凹部から凸までの高さを求め、(ひとつの山は、2つの高さを持つ)高さの和を求め、基準長さLで割った値のアークタンジェントを計算することで求められる角度である。
θa=tan-1[(h1+h2+h3+h4+・・・・・+hn)/L]
すなわち、映像光の迷光成分によるコントラスト低下の大小関係は、外光の反射特性に近似して考慮することが可能である。なお、迷光成分による黒彩感についても同様である。また、防眩層に強度は小さくとも大きな角度の拡散を持たせることでLCDの漏れ光を広く拡散させる従来の画角重視の方法は、前述の迷光成分の発生を促進することとなり、ことに暗室での高度な黒味に欠けるものであった。
対して透過拡散が大きいと迷光成分が発生し、内部映像光の指向性が低くなり、映像が白茶けたように見えるため肌色などの表示に対して活き活きとした表示とならない。
また、動画防眩性については動画鑑賞時に限った微弱な耐映り込み性であることから、画像の切れを満たしていれば、動画防眩性を同時に満たしていることになり、一方、動画鑑賞に限れば、画像の切れを満たさずとも、動画防眩性を満たしていれば良い。
すなわち、(a)透過拡散が小さい(正透過強度が高い)こと、(b)正反射強度成分が小さいこと、(c)正反射近傍の拡散に変換すること、の三要素を満足させることである。
換言すればQ/Uは、表面形状(外部拡散要素)に関しては、正透過となる平坦部と正透過以外の角度となる凹凸部の比率に近似される為、凹凸の傾斜の角度と凹凸の存在確率に関連し、内部拡散に関しては、拡散粒子と透光性樹脂の屈折率差、拡散粒子との衝突確率及び形状に関連し、表面形状と内部拡散の相互作用に関しては、前記相互作用をより弱めあう程度と強めあう程度とに関連することで、黒彩感と切れの良し悪しを決定している。
一般に、屈折率nの層と空気との界面において、層内部から光が角度θで界面に入射するときの界面における反射割合は、p偏光の場合をRp、s偏光の場合をRsとすると、反射の法則およびスネルの法則に則って計算することにより以下の式で表される。
Rp=((cosθ-n×cos(arcsin(n×sinθ)))/(cosθ+n×cos(arcsin(n×sinθ))))2
Rs=((cos(arcsin(n×sinθ))-n×cosθ)/(cos(arcsin(n×sinθ))+n×cosθ))2
また、表面凹凸を有する防眩層において、内部拡散が小さい場合の透過拡散角度ψは、表面凹凸の傾斜角度をθs、透光性樹脂の屈折率をnBとしたとき、スネルの法則に基づいて算出され、
ψ=arcsin(nB×sinθs)-θs
となる。
したがって、迷光成分を発生させないためには、30度以上の透過拡散が存在しないことが好ましく、20度から反射が増大し始めることから透過拡散を20度以下とすることで確実に迷光成分の発生を防止することができる。
すなわち、透光性樹脂は硬化するときに体積が収縮する。一方、拡散粒子は収縮することが無いため、透光性樹脂の収縮に拡散粒子が抵抗することで拡散粒子に対応する位置の表面が凸部となって凹凸が形成されるのであるから、拡散粒子が柔軟性を有していれば透光性樹脂の硬化収縮に対する抵抗力が減じることになり表面凹凸の傾斜角は緩やかになる。
しかしながら、柔軟性のある拡散粒子は、低重合度で低架橋密度の粒子であるため、防眩層用塗液中で膨潤しやすく粘度変化やゲル化がおこり、塗工の安定性がなく実用に供し得ないものであった。
本発明においては、以上のように、Q/Uについて注目することを一つの特徴とするが、さらにLog10(Q30/Q)に着目することで課題の解決を確実にするとともに、さらに優れた効果を得るために、他のパラメータ、すなわち、特許請求の範囲の各請求項において規定するような種々のパラメータとの任意の組み合わせにより、本発明の目的を達成することができる。
なお、含浸層の屈折率は拡散粒子の屈折率に比べ、より透光性樹脂の屈折率に近づくため、40%以上含浸すると、上記効果は得られたとしても、透光性樹脂と拡散粒子の屈折率との差により発現していた内部拡散が減少するので、黒しまり性や、殊にギラツキ防止性を損なう恐れもある。
(1)透明基材の少なくとも一方の面に、透光性樹脂と拡散粒子を含む防眩層を有し、前記防眩層は前記透明基材とは反対側の面に凹凸を有し、前記凹凸は主に前記透光性樹脂を構成する成分の全部又は一部が含浸した含浸層を有する前記拡散粒子に基づく凸部により形成されてなる防眩シートであって、前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過方向の輝度をQ、正透過から30度の方向の輝度をQ30、正透過から+2度の方向の輝度と正透過から+1度の方向の輝度とを結ぶ直線、および、正透過から-2度の方向の輝度と正透過から-1度の方向の輝度とを結ぶ直線を各々正透過に外挿した透過強度の平均値をUとしたとき、下記の(式1)および(式2)を満たすことを特徴とする防眩シート。
(式 1) 10<Q/U<36
(式 2) Log10(Q30/Q)<-6
(2)前記防眩層の厚みをT、前記防眩層中での前記透光性粒子の半径をR、前記含浸層の厚みをPとしたとき、下記の(式3)および(式4)を満たすことを特徴とする防眩シート。
(式 3) 0.25<R/T<0.45
(式 4) 5%<P/R<40%
(3)前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過から20度の方向の輝度をQ20としたとき、下記の(式5)を満たすことを特徴とする防眩シート。
(式 5) Log10(Q20/Q)<-5.5
(4)防眩シートの内部ヘイズ値をHi(%)とし、さらに、防眩シートの全へイズ値をHa(%)としたとき、下記の(式6)を満たすことを特徴とする防眩シート。
(式 6) 0 ≦ Ha-Hi≦4
(5)JIS K7105に基づく防眩シートの透過画像鮮明度での光学櫛0.125mmに対する光学櫛2.0mmの値の比をDとしたとき、下記の(式7)を満たすことを特徴とする防眩シート。
(式 7) D<2
(6)最表層に低屈折率層を形成してなる防眩シート。
(7)上記防眩シートを用いた偏光板。
(8)上記防眩シートまたは上記偏光板を用いた画像表示装置。
(9)透明基材の少なくとも一方の面に、透光性樹脂と拡散粒子を含む防眩層を有し、前記防眩層は前記透明基材とは反対側の面に凹凸を有し、前記凹凸は主に前記透光性樹脂を構成する成分の全部又は一部が含浸した含浸層を有する前記拡散粒子に基づく凸部により形成されてなる防眩シートであって、前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過方向の輝度をQ、正透過から30度の方向の輝度をQ30、正透過から+2度の方向の輝度と正透過から+1度の方向の輝度とを結ぶ直線、および、正透過から-2度の方向の輝度と正透過から-1度の方向の輝度とを結ぶ直線を各々正透過に外挿した透過強度の平均値をUとしたとき、防眩シートの特性が下記の(式1)および(式2)を満たすように制御することを特徴とする防眩シートの製造方法。
(式 1) 10<Q/U< 36
(式 2) Log10(Q30/Q)<-6
また、この防眩シートを用いることにより、動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れの改善方法を提供することができる。
(式 1) 10 <Q/U< 36
(式 2) Log10(Q30/Q)<-6
なお、拡散透過強度の測定は、具体的には以下のように測定する。
防眩シートの裏面から(防眩シートの観察者側と反対側の面)から垂直に可視光線を照射する。光束が防眩シートに入射し、拡散透過した光を-85度~+85度までの範囲で1度ごとに受光器を走査することにより拡散透過強度を測定する。
ここで、「GC5000L」の光束の径は約3mmであって、この径は一般に用いられているゴニオフォトメーターの平均的な光束の径となっている。
Log10(Q30/Q)<-6 (x)
Log10(Q30/Q)が-6未満となるようにすることによって、黒彩感、暗室黒味が優れた液晶表示装置用防眩シートを得ることができる。
さらに、下記式(y)を満たすことにより、より一層暗室での高度な黒味に優れた液晶表示装置用防眩シートを得ることができる。
Log10(Q20/Q)<-5.5 (y)
なお、Q30あるいはQ20が非常に小さくて測定器で検出できない場合は、Log10(Q30/Q)あるいはLog10(Q20/Q)の値を-10.0とする。
10<Q/U< 36 (z)
Q/Uが10超となるようにすることによって、黒彩感に優れるとともに、36未満となるようにすることによって動画防眩性に優れた液晶表示装置用防眩シートを得ることができる。
また、前記透明基材に含浸性を有する塗液および/または、更に膨潤する溶剤を含む塗液では、硬化時に前記透明基材は柔軟性を有するので、前記有機微粒子に接触する部位において凹状に変形することで、拡散層表面の凸部をよりなだらかにすることができる。
また、上記有機微粒子(A1)が、コア-シェルタイプの微粒子では、コアにアクリル樹脂からなる微粒子を用いたポリスチレン微粒子や、逆にコアにスチレン樹脂からなる微粒子を用いたポリアクリル微粒子が存在する。
上記アクリル系モノマーとして、メチルメタクリレートを用いて得られた架橋アクリル樹脂が特に好適である。
また、防眩層の厚さTと前記有機微粒子の前記平均粒径の半分である粒子の半径をRとしたとき
0.25<R/T<0.45
を満たすことが好ましい。0.25超であれば好ましい動画防眩性を得ることが出来、0.45未満であれば、透光性粒子が塗膜層最表面に突出したり、凹凸が急峻なものとはならず、滑らかなものとなり、ゆるやかに埋もれさせることで、好ましいコントラストを得ることが担保できるからである。
また、透光性粒子の粒径のばらつきが少ないほど、拡散特性にばらつきが少なく、拡散透過強度分布設計が容易となる。より具体的には、重量平均による平均径をMV、累積25%径をd25、累積75%径をd75としたとき、(d75-d25)/MVが0.25以下であることが好ましく、0.20以下であることが更に好ましい。
粒径のばらつきの調整方法としては、例えば、合成反応の条件を調整することで行うことができ、また、合成反応後に分級することも有力な手段である。分級では、その回数を上げることやその程度を強くすることで、望ましい分布の粒子を得ることができる。分級には風力分級法、遠心分級法、沈降分級法、濾過分級法、静電分級法等の方法を用いることが好ましい。なお、透光性粒子が有機微粒子である場合、塗液中の成分が有機微粒子に浸透した含浸層を有する有機微粒子では本来の粒子の粒径と異なることがあり得るが、上記粒径とは、拡散要素を有する層中での粒子の径を言う。
上記含浸層は、上記拡散層中の有機微粒子(A2)の外表面からその中心に向かって、上記放射線硬化型透光性樹脂が含浸して形成された層である。なお、上記含浸層は、放射線硬化型透光性樹脂のうち低分子量成分、すなわち、主としてモノマーが含浸して形成された層であり、高分子成分である放射線硬化型透光性樹脂の重合物、すなわち、ポリマーやオリゴマーは含浸し難い。モノマーの中でも、重量平均分子量が1000以下のものが好ましい。より好ましくは、含浸しやすいため、重量平均分子量が小さい250~600以下のモノマー、例えば、トリメチロールプロパントリアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールテトラアクリレート、ジペンタエリスリトールペンタアクリレート、ジペンタエリスリトールヘキサアクリレート、およびその変性品などがよい。
上記含浸層は、例えば、上記拡散層中の有機微粒子(A2)の断面を電子顕微鏡(TEM、STEM等の透過型が好ましい)観察することで判別することができ、染色することでより含浸層の観察が容易となることがある。
なお、上記含浸層に含浸する放射線硬化型透光性樹脂は、構成する全成分が含浸されたものであってもよく、構成する成分の一部が含浸したものであってもよい。
なお、前記粒子(B)による高さの高い凸部が形成されることを防止することをより確実にする意味から、前記粒子(B)も含浸層を有することが好ましい。
5%<P/R<40%
5%以下であると、上述した含浸層を形成することで得られる効果を充分に得られず、40%以上であると、防眩層表面の凸部の形成が不充分となり、動画防眩性が劣ることがあるのみならず、有機微粒子(A2)の内部拡散機能が充分発揮されなくなり、ギラツキの防止効果を充分に得られない。
なお、上記P/Rは、防眩シートの断面電子顕微鏡写真で観察される有機微粒子(A)の断面における含浸層の厚さの平均値を、前記有機微粒子の電子顕微鏡写真に基づく半径の平均値で割った値を意味する。
トルエンとメチルイソブチルケトンの混合物(質量比7:3)を、放射線硬化型透光性樹脂(ペンタエリスリトールテトラアクリレート(PETTA、製品名:M-450、東亜合成(株)製)60質量部、ジペンタエリスリトールヘキサアクリレート(DPHA、日本化薬(株)製)10質量部、及びイソシアヌル酸PO変性トリアクリレート(製品名:M-313、東亜合成(株)製)30質量部の混合物)100質量部に対して、190質量部配合した塗液を調製する。
一方、30質量部を超えると、上記塗液中で有機微粒子(A1)同士の凝集が生じ、拡散層の表面に大きな凸部が形成されて所望の性能が得られず、白茶けやギラツキが発生してしまうことがある。
上記有機微粒子(A1)の含有量のより好ましい下限は1.0質量部、より好ましい上限は20質量部である。この範囲内にあることで、より上述の効果を確実にすることができる。
したがって、液晶表示装置用防眩シートのヘイズをHa、内部拡散により生じるヘイズをHiとすると、Ha-Hiは、内部拡散要素と表面凹凸との相互作用によるヘイズおよび外部ヘイズの和と言うことができる。
前記含浸層を有する有機微粒子においては、前述の表面凹凸制御の観点からは、P/Rが5~40%の範囲が好ましいが、内部拡散性能を維持するとの観点からは、塗液中の成分が含浸していない中心部が可視光波長以上の径を有することが好ましく、1μm以上の径を有することがより好ましい。
また、粒子径や粒子上部に存在する透光性樹脂の厚みについても、粒子中心近傍を通る断面を撮影することにより、上記と同様の方法で観察及び測定し、平均値より求めることが出来る。
これらの屈折率は、材料自身を測定する以外に、実際に液晶表示装置用防眩シートとした後に、粒子または粒子のかけらを膜から取り出して測定したり、防眩シートの切断面をエリプソメーターで測定する方法、防眩シートのレーザー干渉を測定する方法等により測定することもできる。
このような上記放射線硬化型透光性樹脂としては、上述した有機微粒子(A1)を膨潤させるものが好適に挙げられ、透明性のものが好ましく、例えば、紫外線又は電子線により硬化する電離放射線硬化型樹脂が挙げられる。なお、本明細書において「(メタ)アクリレート」とは、メタクリレート及びアクリレートを指すものである。
また、本明細書において、モノマーとは、電離放射線硬化してポリマー膜となるために、このポリマー膜の基本構造の構成単位となりうる分子を全て含み、不飽和結合を有する。
本発明において、含浸性を有する低分子量のモノマーは、重量平均分子量が1000以下であることが好ましく、250~600であることがより好ましい。
光重合性官能基としては、(メタ)アクリロイル基、ビニル基、スチリル基、アリル基等の不飽和の重合性官能基等が挙げられる。
また、プレポリマー及びオリゴマーとしては、ウレタン(メタ)アクリレート、ポリエステル(メタ)アクリレート、エポキシ(メタ)アクリレート等のアクリレート、不飽和ポリエステル、エポキシ樹脂等が挙げられる。
また、ベンゾフェノン類としては、ベンゾフェノン、ヒドロキシベンゾフェノン、4ベンゾイル-4’-メチルジフェニルサルファイド、2,4-ジクロロベンゾフェノン、4,4-ジクロロベンゾフェノンおよびp-クロロベンゾフェノン、4,4’-ジメチルアミノベンゾフェノン(ミヒラーケトン)、3,3’,4,4’-テトラ(t-ブチルパーオキシカルボニル)ベンゾフェノン等が使用可能である。
この原因は、一種類の粒子であっても、例えば、乾燥途上で(通常2種以上入れるので)溶剤の揮発性の差により組成変動が生じるので、凝集と分散とを制御が困難となるためであると類推している。このことは、殊に親油、親水度合いが異なる二種以上の粒子を用いる、場合に顕著である。そのため急峻な凹凸などが生じる点などで、ガサツキやギラツキの制御ができなくなる恐れがある。
具体的には、飽和蒸気圧、透明基材への浸透性等を考慮して選定される。
また、粒子に含浸性を有する溶剤を用いることで、透明樹脂の成分の少なくとも一部が粒子に浸透しやすくなり、前述の含浸層の調整が可能となり拡散透過強度を制御することにつながる。
なお、上記有機微粒子(A1)の含浸層の形成は、該有機微粒子(A1)を膨潤させる性質を持つ溶剤が存在することで、上記放射線硬化型透光性樹脂の膨潤性の程度によらず、より確実に行うことができるので、少なくとも上記溶剤は、上記有機微粒子(A1)を膨潤させる性質を持つ溶剤を含有することがより好ましい。
本発明の防眩性フィルムでは、上記放射線硬化型透光性樹脂及び溶剤の組み合わせとしては、なかでも、放射線硬化型透光性樹脂として、分子量が小さく含浸しやすいことから(メタ)アクリレートモノマーと、溶剤として、上記有機微粒子(A1)を膨潤させる性質の強いケトン、エステル系とを組み合わせて用いることが好ましい。
例えば、硬度などの物理特性、反射率、拡散性などの光学特性などの向上のため、各種無機粒子を添加することができる。
界面活性剤としては、シリコーンオイル、フッ素系界面活性剤、好ましくはパーフルオロアルキル基を含有するフッ素系界面活性剤などが挙げられる。溶剤を含む樹脂組成物を塗工し、乾燥する場合、塗膜内において膜表面と内面とに表面張力差などを生じ、それによって膜内に多数の対流が引き起こされる。この対流はベナードセル構造のゆず肌や塗工欠陥となる。
また、黒彩感や画像のキレなどに悪影響を及ぼす。前述のような界面活性剤を用いると、この対流を防止することができるため、欠陥やムラのない凹凸膜が得られるだけでなく、透過拡散輝度特性の調整も容易となる。
特に、含浸性故に表面凹凸を滑らかにし易いこと以外にも、本発明の液晶表示装置用防眩シートを偏光板とともに用いる場合では、偏光を乱さないことからTACフィルムが、耐候性から環状ポリオレフィンフィルムが、機械的強度と平滑性を重視する場合は、ポリエチレンテレフタレートフィルムなどのポリエステルフィルムが好ましい。
また、前記透明基材は多層であっても単層であってもよいし、塗膜との接着性を目的として表面にプライマー層を設けてもよい。
なお、Rzは、JIS B0601 1994に準拠した方法を元に、カットオフ値を2.5mm、評価速さを0.5mm/sとして測定した値である。
また、耐スチールウール擦り性では、10往復擦り試験をしてもキズが確認されない最大荷重は、200g/cm 2以上であることが好ましく、500g/cm 2以上であることがさらに好ましく、700g/cm 2以上であることが特に好ましい。
帯電防止性能を付与するには、例えば、導電性微粒子、導電性ポリマー、4級アンモニウム塩、チオフェンなどと反応性硬化樹脂を含む導電性塗工液を塗工する方法、或いは透明膜を形成する金属や金属酸化物等を蒸着やスパッタリングして導電性薄膜を形成する方法等の従来公知の方法を挙げることができる。
また、帯電防止層をハードコート、耐映りこみ性、反射防止等の機能層の一部として使用することもできる。
また、該光学フィルムが蓄積できる最大電圧である、いわゆる飽和帯電圧としては、10kVの印加電圧で2kV以下であることが好ましい。
防汚層は防汚剤の添加により付与することができ、防汚剤としては、フッ素系化合物、珪素系化合物、またはこれらの混合物が挙げられ、特にフロロアルキル基を有する化合物が好ましい。
前記低屈折率層は、0.1μm程度の厚みを有する層であって、外光の反射を干渉により低減するものである。前記低屈折率層は、なんら限定されることは無いが、多孔質または中空シリカを添加した紫外線硬化樹脂を含む塗液を塗布及び硬化により形成することが好ましい。前記塗液を塗布及び硬化することにより、防眩層表面の凸部に存在した微小でシャープな凹凸がスムージングされてより滑らかになり、反射防止効果に加えて、より一層黒彩感の向上を図ることができる。
塗布の方法としては、種々の方法を用いることができ、例えば、ディップコート法、エアーナイフコート法、カーテンコート法、ロールコート法、ワイヤーバーコート法、グラビアコート法、ダイコート法、ブレードコート法、マイクログラビアコート法、スプレーコート法、スピンコート法、リバースコート法等の公知の方法が用いられる。
上記塗液を調製して静置することなく防眩層を形成すると、使用する有機微粒子(A)の架橋度や、放射線硬化型透光性樹脂及び/又は溶剤による上記有機微粒子(A)の膨潤の度合いを適宜調整した場合であっても、拡散層中の有機微粒子(A2)に充分な含浸層を形成することができないことがあるからである。
1.膜厚:T(μm)の測定方法
共焦点レーザー顕微鏡(LeicaTCS-NT:ライカ社製:対物レンズ「10~100倍」)にて、防眩シートの断面を観察し、界面の有無を判断し下記の評価基準で判断した。
(1)ハレーションのない鮮明な画像を得るため、共焦点レーザー顕微鏡に、湿式の対物レンズを使用し、かつ、光学積層体の上に屈折率1.518のオイルを約2ml乗せて観察した。オイルの使用は、対物レンズと防眩層との間の空気層を消失させるために用いた。
総ヘイズ値は、JIS K-7136に従って測定することができる。測定機器として、ヘーズメーターHM-150(村上色彩技術研究所)を使用した。なお、ヘイズ、は、透明基材面を光源に向けて測定する。
本発明で使用している内部ヘイズは、以下のように求められる。液晶表示装置用防眩シートの観察者面側最表面にある凹凸上に、表面凹凸を形成する樹脂と屈折率が等しいか少なくとも屈折率差が0.02以下である樹脂、本発明の場合は各実施例・比較例から微粒子を除いたものをワイヤーバーで乾燥膜厚が8μmとなるように塗布し、70℃で1分間乾燥後、100mj/cm2の紫外線を照射して硬化する。
このシートのヘイズを、JIS K-7136に従って総ヘイズと同様な方法で測定し、内部ヘイズとして求めることができる。
各製造例にて作製された液晶表示装置用防眩シートについて、明細書本文中に記載の方法により測定した。
ソニー社製液晶テレビ「KDL-40X2500」の最表面の偏光板を剥離し、表面塗布のない偏光板を貼付した。
次いで、その上に各製造例で作成したサンプルを防眩層側が最表面となるように、光学フィルム用透明粘着フィルム(全光線透過率91%以上、ヘイズ0.3%以下、膜厚20~50μmの製品、例えばMHMシリーズ:日栄加工(株)製など)により貼付した。
該液晶テレビを、照度が約1,000Lxの環境下の室内に設置し、メディアファクトリー社のDVD「オペラ座の怪人」を表示して、液晶テレビから1.5~2.0m程度離れた場所から上下、左右様々な角度から、該映像を被験者15人が鑑賞することで、下記項目に関して3段階評価の感応評価を実施した。評価基準は以下のとおりである。
立体感
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
躍動感
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
黒彩感
○:立体感及び躍動感が全て○以上
△:立体感及び躍動感が○及び△/又はともに△である
×:立体感及び躍動感に一つでも×がある
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
○:ギラツキが許容できると答えた人が10人以上
△:ギラツキが許容できると答えた人が5~9人
×:ギラツキが許容できないと答えた人が4人以下
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
○:良好と答えた人が10人以上
△:良好と答えた人が5~9人
×:良好と答えた人が4人以下
JIS K7105に基づき防眩シートの透過画像鮮明度での光学櫛0.125mmおよび2.0mmの値を求めその比を計算する。測定機器として、写像性測定器ICM-1T(スガ試験機)を使用した。
実施例及び比較例で得られた防眩性フィルムについて、拡散層の厚さ方向に切断し、拡散粒子である有機微粒子(A)を1個以上少なくとも含む断面を倍率3000~5万倍で透過型電子顕微鏡(STEM)にて観察を行い、放射線硬化型透光性樹脂が有機微粒子(A)に含浸している部分で、有機微粒子(A)と周りの透光性樹脂との境界が比較的明瞭であり、かつ、有機微粒子(A)内に放射線硬化型透光性樹脂が最も含浸していると見られる部分2点の厚さを測定し、合計5個の有機微粒子(A)について同様に測定し、10点の測定結果の平均値を算出した。
透明基材としてトリアセチルセルロース(富士フィルム(株)製、厚さ80μm)を用意した。
次に、透光性樹脂である放射線硬化型透光性樹脂として、ペンタエリスリトールテトラアクリレート(PETTA、製品名:M-450、東亜合成(株)製)60質量部、ジペンタエリスリトールヘキサアクリレート(DPHA、日本化薬(株)製)10質量部、及びイソシアヌル酸PO変性トリアクリレート(製品名:M-313、東亜合成(株)製)30質量部の混合物を用い(屈折率1.51)、これに拡散粒子である有機微粒子(A)として、アクリル粒子(屈折率1.49、平均粒径5.0μm)を、上記放射線硬化型透光性樹脂100質量部に対して、9.0質量部、これに溶剤としてトルエンとメチルイソブチルケトンとの混合物(質量比7:3)を、放射線硬化型透光性樹脂100質量部に対して、190質量部、及び重合開始剤イルガキュア184(BASFジャパン製)、レベリング剤ポリエーテル変性シリコーン(TSF4460、モメンティブパフォーマンスマテリアルズ製)を、上記放射線硬化型透光性樹脂100質量部に対して、それぞれ5質量部、0.04質量部配合して塗液を調製した。
得られた塗液を24時間静置した後、マイヤーバーを用いて光透過性基材に塗工し、1.2m/sの流速で70℃の乾燥空気を流通させ、1分間乾燥させた。
その後、塗膜に紫外線を照射して(窒素雰囲気下にて200mJ/cm2)放射線硬化型透光性樹脂を硬化させて拡散層を形成し、防眩シートを作製した。
塗液に添加する各成分、及び、条件を表1に示したようにした以外は、実施例1と同様にして防眩性フィルムを作製した。なお、2種類の粒子を用いる場合の粒子(B)の添加量は粒子(A)の添加量の30%とした。また、粒子(B)の含浸%は粒子(A)の測定に準じて行った。
塗液に添加する各成分、及び、条件を表1に示したようにした以外は、実施例2と同様にして防眩シートを作製した。
A:低架橋アクリル粒子(屈折率1.49、平均粒径5.0μm)
B:高架橋アクリル粒子(屈折率1.49、平均粒径5.0μm)
C:低架橋アクリル粒子(屈折率1.49、平均粒径3.5μm)
(粒子B)
D:高架橋ポリスチレン粒子(屈折率1.59、平均粒径2.5μm)
E:低架橋ポリスチレン粒子(屈折率1.59、平均粒径2.5μm)
(透光性樹脂)
P:ペンタエリスリトールテトラアクリレート(PETTA、製品名:M-450、東亜合成(株)製)60質量部、ジペンタエリスリトールヘキサアクリレート(DPHA、日本化薬(株)製)10質量部、及びイソシアヌル酸PO変性トリアクリレート(製品名:M-313、東亜合成(株)製)30質量部の混合物(屈折率1.51)
Q:ペンタエリスリトールテトラアクリレート(PETTA、製品名:M-450、東亜合成(株)製)(屈折率1.51)
R:酢酸ビニル樹脂(重量平均分子量100,000)55質量部とメタクリル酸メチル樹脂(重量平均分子量75,000)45質量部との混合物(屈折率1.47)
(溶剤)
X:トルエンとメチルエチルケトンの混合物(質量比71:28)
Y:トルエンとメチルイソブチルケトンの混合物(質量比70:30)
Z:トルエンとイソプロピルアルコールの混合物(質量比75:25)
そして、この防眩シートを用いることにより、動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れを改善することができる。
2.8.防眩層
3.拡散粒子
4.透光性樹脂
5.9.11.透明基材
6.12.偏光板
10.偏光層
13.ガラス基板
14.カラーフィルタ
15.透明電極
16.液晶セル
17.バックライト
18.ガラス基板(前面板)
19.表示電極(透明電極+パス電極)
20.透明誘電体層
21.MgO
22.誘電体層
23.ガラス基板(背面板)
24.アドレス電極
25.蛍光体
26.プラズマ表示パネル(PDP)
27.前面フィルタ
28.スペーサー
29.筺体
30.ビス
31.前面(表示面)
Claims (15)
- 透明基材の少なくとも一方の面に、透光性樹脂と拡散粒子を含む防眩層を有し、前記防眩層は前記透明基材とは反対側の面に凹凸を有し、前記凹凸は主に前記透光性樹脂を構成する成分の全部又は一部が含浸した含浸層を有する前記拡散粒子に基づく凸部により形成されてなる防眩シートであって、前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過方向の輝度をQ、正透過から30度の方向の輝度をQ30、正透過から+2度の方向の輝度と正透過から+1度の方向の輝度とを結ぶ直線、および、正透過から-2度の方向の輝度と正透過から-1度の方向の輝度とを結ぶ直線を各々正透過に外挿した透過強度の平均値をUとしたとき、下記の(式1)および(式2)を満たすことを特徴とする防眩シート。
(式 1) 10<Q/U< 36
(式 2) Log10(Q30/Q)<-6 - 前記防眩層の厚みをT、前記防眩層中での前記透光性粒子の半径をR、前記含浸層の厚みをPとしたとき、下記の(式3)および(式4)を満たすことを特徴とする請求項1に記載の防眩シート。
(式 3) 0.25<R/T<0.45
(式 4) 5%<P/R<40% - 前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過から20度の方向の輝度をQ20としたとき、下記の(式5)を満たすことを特徴とする請求項1乃至2のいずれか1項に記載の防眩シート。
(式 5) Log10(Q20/Q)<-5.5 - 防眩シートの内部ヘイズ値をHi(%)とし、さらに、防眩シートの全へイズ値をHa(%)としたとき、下記の(式6)を満たすことを特徴とする請求項1乃至3のいずれか1項に記載の防眩シート。
(式 6) 0 ≦ Ha-Hi≦4 - JIS K7105に基づく防眩シートの透過画像鮮明度での光学櫛0.125mmに対する光学櫛2.0mmの値の比をDとしたとき、下記の(式7)を満たすことを特徴とする請求項1乃至4のいずれか1項に記載の防眩シート。
(式 7) D<2 - 最表層に低屈折率層を形成してなる請求項1乃至5のいずれか1項に記載の防眩シート。
- 請求項1乃至6のいずれか1項に記載の防眩シートを用いた偏光板。
- 請求項1乃至6記載の防眩シートまたは請求項7記載の偏光板を用いた画像表示装置。
- 透明基材の少なくとも一方の面に、透光性樹脂と拡散粒子を含む防眩層を有し、前記防眩層は前記透明基材とは反対側の面に凹凸を有し、前記凹凸は主に前記透光性樹脂を構成する成分の全部又は一部が含浸した含浸層を有する前記拡散粒子に基づく凸部により形成されてなる防眩シートであって、前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過方向の輝度をQ、正透過から30度の方向の輝度をQ30、正透過から+2度の方向の輝度と正透過から+1度の方向の輝度とを結ぶ直線、および、正透過から-2度の方向の輝度と正透過から-1度の方向の輝度とを結ぶ直線を各々正透過に外挿した透過強度の平均値をUとしたとき、防眩シートの特性が下記の(式8)および(式9)を満たすように制御することを特徴とする防眩シートの製造方法。
(式 8) 10 <Q/U<36
(式 9) Log10(Q30/Q)<-6 - 透明基材の少なくとも一方の面に、透光性樹脂と拡散粒子を含む防眩層を有し、前記防眩層は前記透明基材とは反対側の面に凹凸を有し、前記凹凸は主に前記透光性樹脂を構成する成分の全部又は一部が含浸した含浸層を有する前記拡散粒子に基づく凸部により形成されてなる防眩シートを、画像表示装置の視認側に有する、動画像と静止画像との共用に適した画像表示装置において、前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過方向の輝度をQ、正透過から30度の方向の輝度をQ30、正透過から+2度の方向の輝度と正透過から+1度の方向の輝度とを結ぶ直線、および、正透過から-2度の方向の輝度と正透過から-1度の方向の輝度とを結ぶ直線を各々正透過に外挿した透過強度の平均値をUとしたとき、下記の(式10)および(式11)を満たすことを特徴とする、動画像と静止画像との共用に適した画像表示装置の黒彩感及び画像の切れを改善する方法。
(式 10) 10 <Q/U< 36
(式 11) Log10(Q30/Q)<-6 - 前記防眩層の厚みをT、前記防眩層中での前記透光性粒子の半径をR、前記含浸層の厚みをPとしたとき、下記の(式12)および(式13)を満たすことを特徴とする請求項10に記載の画像表示装置の黒彩感及び画像の切れを改善する方法。
(式 12) 0.25<R/T<0.45
(式 13) 5%<P/R<40% - 前記防眩シートに透明基材側から垂直に可視光線を照射した際の正透過から20度の方向の輝度をQ20としたとき、下記の(式14)を満たすことを特徴とする請求項10乃至11のいずれか1項に記載の画像表示装置の黒彩感及び画像の切れを改善する方法。
(式 14) Log10(Q20/Q)<-5.5 - 防眩シートの内部ヘイズ値をHi(%)とし、さらに、防眩シートの全へイズ値をHa(%)としたとき、下記の(式15)を満たすことを特徴とする請求項10乃至12のいずれか1項に記載の画像表示装置の黒彩感及び画像の切れを改善する方法。
(式 15) 0 ≦ Ha-Hi≦4 - JIS K7105に基づく防眩シートの透過画像鮮明度での光学櫛0.125mmに対する光学櫛2.0mmの値の比をDとしたとき、下記の(式16)を満たすことを特徴とする請求項10乃至13のいずれか1項に記載の画像表示装置の黒彩感及び画像の切れを改善する方法。
(式 16) D<2 - 最表層に低屈折率層を形成してなる請求項10乃至14のいずれか1項に記載の画像表示装置の黒彩感及び画像の切れを改善する方法。
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WO2015186613A1 (ja) * | 2014-06-04 | 2015-12-10 | コニカミノルタ株式会社 | マット層を有する積層フィルム |
JP2021513109A (ja) * | 2018-05-11 | 2021-05-20 | エルジー・ケム・リミテッド | 防眩フィルムおよびディスプレイ装置 |
JP7134549B2 (ja) | 2018-05-11 | 2022-09-12 | エルジー・ケム・リミテッド | 防眩フィルムおよびディスプレイ装置 |
Also Published As
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KR101858305B1 (ko) | 2018-06-28 |
US9562994B2 (en) | 2017-02-07 |
JPWO2013035656A1 (ja) | 2015-03-23 |
CN103797385B (zh) | 2017-03-22 |
TWI554777B (zh) | 2016-10-21 |
JP5991322B2 (ja) | 2016-09-14 |
CN103797385A (zh) | 2014-05-14 |
TW201316023A (zh) | 2013-04-16 |
KR20140057240A (ko) | 2014-05-12 |
US20140177060A1 (en) | 2014-06-26 |
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